EP4202181A1 - Gear wheel pump - Google Patents

Abstract

The invention relates to a gear pump (1) for conveying a fluid stream (F), the direction of flow (Si, S₂) of which can be reversed by switching between a conveying and a flushing mode, with two gear wheels in a gear space (35 ) arranged gears (4.1, 4.2) and an auxiliary space (101) fluidically connected to the gear space (35), wherein the fluid flow (F) consists of a main flow portion (H) flowing through the gear space (35) and a main flow component (H) flowing at least partially through the auxiliary space (101 ) flowing secondary flow component (N) is formed and means (102) are provided for increasing the secondary flow component (N) in the flushing mode. Further objects of the invention are a pump arrangement (100) and a method for conveying a fluid flow (F) with such a gear pump (1).

Description

The invention relates to a gear pump for delivering a fluid flow, the direction of flow of which can be reversed by switching between a delivery mode and a flushing mode, with two gear wheels arranged in a gear wheel space and an auxiliary space fluidically connected to the gear wheel space, the fluid flow being composed of a main flow component flowing through the gear wheel space and a secondary flow portion flowing at least partially through the secondary space. A further object of the invention is a pump arrangement and a method for conveying a fluid flow with such a gear pump.

Gear pumps of this type are used in various areas of technology to convey fluid flows, for example as a feed pump for oil or other lubricants or liquids, in vending machines or other systems in the beverage industry, etc.

A gear pump generally has a gear space that accommodates the gears and has an inlet and an outlet for the fluid flow. One of the gears is usually driven in rotation via a shaft and the other is designed to rotate with it. The drive for the shaft is arranged outside of the gear space and the shaft is guided through a bushing into the gear space. To seal the rotating shaft from the gear space, shaft sealing rings are used, which enable a separation between the gear-side end of the shaft through which fluid flows and the dry, drive-side end of the shaft. For design reasons, these shaft seals cannot be attached directly in or on the gear space. Rather, it is necessary to arrange the shaft sealing ring in an ancillary space which, as a rule, is flow-connected to the gear wheel space via the passage having a certain annular gap and is sufficiently dimensioned to accommodate the shaft seal.

To convey the fluid, a pressure gradient is generated in the gear space via the teeth of the mutually engaging rotating gears, which causes a fluid flow from the inlet to the outlet of the gear space.

In this pumping operation, a certain proportion of the fluid flow also flows through the annular gap of the bushing into the side room. In the case of simply designed gear pumps, the fluid collects or backs up as a result in the adjoining space. While this is usually harmless for oil-conveying gear pumps, for gear pumps in other applications, for example from the point of view of hygiene, undesirable. It has therefore proven useful in practice to provide an additional outflow opening, designed in the manner of ventilation, between the gear wheel space and the adjacent space. The outflow opening is dimensioned larger than the annular gap, so that in particular when the gears are at a standstill after the gear pump has been switched off, the fluid present in the adjacent space can drip off and the adjacent space is also emptied. This avoids accumulations of fluid that are hygienically unsafe and remain in the adjoining room for long periods of time.

During pumping operation, a certain proportion of the fluid flow in such gear pumps flows continuously out of the gear space via the annular gap in the area of the passage into the secondary space and through the outflow opening back into the gear space. As a result, the fluid flow is divided into a main flow component and a generally much smaller secondary flow component. The secondary flow portion, which forms alongside the main flow portion flowing from the inlet to the outlet within the gear space, does not impair the operation of the gear pump, but also ensures a certain flushing of the secondary space during pumping operation.

In order to further improve the hygiene conditions, gear pumps for the food industry, such as those used in coffee machines, usually have a flushing operation in addition to the pumping operation in order to clean the gear pump and other fluid-carrying components at regular intervals clean. In this flushing operation, the direction of the fluid flow is changed, ie it no longer flows from the inlet to the outlet of the gear chamber, but in the opposite direction from its outlet to the inlet. In order to achieve particularly effective and hygienic cleaning, a cleaning agent is often added to the fluid flow during the rinsing operation.

As much as the outflow opening for draining off the fluid when the gear pump is switched off has proven itself from a hygienic point of view in conveying operation, it has proven to be problematic in known gear pumps for flushing operation. Because during flushing operation, part of the fluid flow flows in the opposite direction through the larger outflow opening into the side chamber, from which it cannot completely flow out via the annular gap, which is often much smaller in terms of flow cross section and limits the side flow portion. As a result, the rinsing of the adjacent room is not optimal and fluid containing cleaning agent can also accumulate in the adjacent room after the rinsing process has already ended. It can be particularly disadvantageous if the flushing fluid accumulated in the adjacent room during flushing operation and mixed with cleaning agents only flows back into the gearwheel space through the outflow opening after switching back to conveying operation and mixes with the fluid to be conveyed, i.e. the milk from a fully automatic coffee machine.

Against this background, it is the object of the present invention to specify a gear pump, a pump arrangement and a method which are characterized by improved hygiene properties both in the conveying and in the rinsing mode.

In the case of a gear pump of the type mentioned at the outset, this object is achieved by the features of patent claim 1 . Advantageous developments are specified in the dependent claims.

The means for increasing the proportion of secondary flow in the flushing operation result in different flow portions in the conveying and flushing operation, as a result of which improved flushing of the adjacent space can be achieved in the flushing operation without impairing the conveying capacity in the conveying operation. A damming of flushing fluid in the side room can due to the improved flushing can be avoided. Increasing the proportion of secondary flow in the scavenging operation reduces the risk of scavenging fluid that has accumulated in the secondary chamber during the scavenging operation getting into the gearwheel space and into the conveying flow during the delivery operation.

In this context, an advantageous embodiment provides that the gear wheels are connected to a drive unit via an intermediate shaft. This allows a quick and user-friendly replacement of the drive unit. The intermediate shaft can be detachably or non-detachably connected to a drive shaft of the drive unit. In this context, it has proven to be advantageous if the intermediate shaft is made of a material that is adapted to the fluid to be pumped. In this way, for example, corrosion on the intermediate shaft can be avoided. In addition, the choice of material for the intermediate shaft can be adapted to the hygiene requirements of the fluid or the area of application, which are particularly high in the food sector.

In this context, it is proposed in a structurally advantageous embodiment that one gear wheel can be driven via the intermediate shaft and the other gear wheel is designed to rotate with it.

It is further proposed that components of the drive unit are arranged in a drive space, with the gear space being located in an area through which fluid flows and the drive space being located in a dry area, with a seal for fluid-tight separation of the gear space in front of the drive space being located in the secondary space. There is a reliable separation between the area of the gear pump through which the fluid flows and the area that is dry. A further advantage lies in the fact that the drive unit can be exchanged in a simple and user-friendly manner, since it has no direct connection to the area through which the fluid flows. Furthermore, the seal Easily accessible due to the arrangement in the adjoining room and can be easily replaced in a way that is easy to assemble and maintain.

In this context, it is further proposed that the intermediate shaft extends from the gear wheel space through the auxiliary space into the drive space. The continuous extension of the intermediate shaft enables low-loss power transmission between the drive unit and the driven gear. In addition, sealing the intermediate shaft in the adjacent space leads to a separation of the area of the gear pump through which fluid flows and the area of the gear pump that is dry, which simplifies the sealing.

With regard to the seal of the intermediate shaft, it is proposed that the intermediate shaft be sealed off in the adjacent space by means of a shaft aligning ring. The use of a shaft sealing ring as a standard part for sealing the shaft is not only advantageous from the point of view of costs, but also with regard to a fault-free and simple assembly of the shaft seal. It is particularly preferred if the shaft sealing ring is designed in the manner of a radial shaft sealing ring.

In a structurally advantageous embodiment, a slide bearing for supporting the intermediate shaft is arranged between the gear wheel space and the adjacent space. Such a plain bearing enables angular errors between the driven gear wheel and the intermediate shaft in the direct vicinity of the gear wheel to be compensated for, as a result of which a reduction in friction and wear can be achieved. The plain bearing can be a hydrodynamic plain bearing. The sliding bearing can be arranged in the area where the intermediate shaft passes through.

A further embodiment provides that the secondary flow component flows at least partially through an annular gap formed in the area of the plain bearing. In the area of the plain bearing or the passage there is a small annular gap and thus a small part of the bypass flow.

In this context, it has proven to be structurally advantageous if the gear pump has an outflow opening that fluidly connects the gear wheel space with the secondary space. A discharge opening of this type, designed in the manner of ventilation, enables fluid to flow out of the adjacent space into the gear wheel space in a simple and reliable manner. Furthermore, the outflow opening can allow the adjacent space to be completely emptied. In particular, the outflow opening allows fluid to drip out of the secondary space into the gear space when the gear pump is at a standstill. For this purpose, the gear pump can be arranged accordingly during operation, so that the fluid can drip off under the influence of gravity. In this way, long-lasting accumulations of the fluid in the side room can be avoided, since the side room is emptied after each pumping process. In addition, a continuous flushing of the adjacent space can also take place through the outflow opening during pumping operation. From a structural and manufacturing point of view, it is particularly advantageous if the outflow opening is designed as a through hole between the gear wheel space and the side space.

In this context, it is advantageous if the cross-sectional area of the annular gap is smaller than the cross-sectional area of the outflow opening. Such a configuration ensures that the side space can be thoroughly flushed during pumping operation, since due to the larger cross-sectional area, a larger amount of fluid can always flow out of the side space through the outflow opening than flows in through the smaller annular gap. Furthermore, this design allows the gear pump to stop a complete dripping of fluid from the adjacent space into the gear space.

In this context, it is further proposed that the secondary flow portion flows along a secondary flow path during conveying operation, which leads through the annular gap, the secondary space and the outflow opening. Such a design of the secondary flow path allows a defined flow through the secondary space and allows a reliable and thorough flushing of the secondary space. The risk of fluid accumulating or accumulating in the adjoining room over longer periods of time is reduced.

With regard to the means for increasing the proportion of secondary flow in the scavenging operation, it is proposed that the means have a closable scavenging channel which extends between the gear wheel space and the secondary space. This makes it possible to increase the proportion of secondary flow in a simple manner, since an additional flow connection between the gear wheel space and the secondary space can be generated by the scavenging channel. From a structural point of view, the closable scavenging channel is preferably designed as a through hole between the gear wheel space and the secondary space with a closing means that interacts with the through hole. The scavenging channel can be designed transversely to the gear wheel space and essentially straight. In particular, the scavenging channel can run essentially parallel to the axis of rotation of the gear wheels, which allows simple demoulding when producing the gear wheel space by primary shaping. Due to the closable configuration, it is possible to keep the scavenging channel closed during pumping operation and to open it during scavenging operation. In pumping operation, the pressure losses can be kept low due to the low proportion of bypass flow when the scavenging channel is closed. Such pressure losses do not play a role in flushing operation and, due to the higher A good scavenging effect can be achieved with the scavenging channel open.

From a structural point of view, it has also proven to be advantageous if the flushing channel is arranged in an area of the gear wheel space in which there is an overpressure during pumping operation and/or if the outflow opening is arranged in an area of the gear wheel space in which a negative pressure prevails during pumping operation . In this way, both a sufficient throughflow and rinsing of the secondary space during conveying operation and an increase in the proportion of secondary flow in the rinsing operation of the secondary space can be achieved. In addition, the dripping of fluid from the adjacent space can be ensured when the gear pump is at a standstill. The arrangement of the outflow opening in a region of the gear space in which there is a negative pressure during delivery operation supports the outflow of the fluid from the secondary space into the gear space.

With regard to the position of the scavenging channel and/or the outflow opening, it has proven to be advantageous if the scavenging channel and/or the outflow opening is arranged below one of the gear wheels, in particular below the driven gear wheel. Such an arrangement of the scavenging duct and/or the outflow opening has proven to be sensible in terms of production technology and also enables a particularly good flow through the scavenging duct and/or the outflow opening. Furthermore, the scavenging channel and/or the outflow opening are arranged outside the area through which the main flow component flows, so that disturbances of the main flow component are avoided.

It is further proposed that the means have a closing device for closing the scavenging channel, which is designed and arranged in such a way that flow through the scavenging channel is only possible during scavenging operation. Such a locking device allows targeted adjustment an increased proportion of bypass flow during flushing operation. Furthermore, a closing device allows a simple and user-friendly control or adjustment of the fluid flow within the gear pump. In addition, by means of the closing device, undesired flow paths can be blocked in a simple and reliable manner during conveying operation, but desired flow paths during flushing operation.

With regard to the closing device, it is proposed that the closing device be designed as a non-return valve. This enables a particularly simple and error-free construction. A reliable and easily controllable closing and opening of the scavenging channel can be achieved for a large number of operating states.

From a structural point of view, it has proven to be preferable if the closing device is arranged at the end of the scavenging channel on the gear wheel side. This is advantageous from the point of view of flow technology, as larger areas of congestion in the scavenging channel are avoided. In addition, such an arrangement enables the locking device to be installed in a particularly simple and error-free manner, for example via the gear wheel space. Furthermore, an arrangement of the locking device at the end of the scavenging channel on the gear wheel side is particularly maintenance-friendly, since it enables the locking device to be easily replaced, for example in the event of a defect.

In an advantageous embodiment, the closing device has a movably mounted closing element which is designed and arranged in such a way that the closing device automatically opens or closes the scavenging channel when switching between the conveying mode and the scavenging mode. Such a design enables a particularly reliable design of the gear pump that is simple in terms of control technology. In addition, the pressure of the fluid can be used to automatically operate the closure device. The closing element can in particular be movable Be configured ball or similar component, or alternatively be designed as an articulated element, for example in the form of a flap or hatch. It is also conceivable for the closing element to be force-assisted, for example in the form of a spring preload or some other restoring element to support the opening or closing movements.

A preferred embodiment provides that the closing element rests against one of the gears in an open position of the closing device, in particular against an end face of one of the gears, and/or in a closed position against a closing surface of the scavenging channel. As a result, defined positions for the closing element can be specified in the open position and the closed position of the closing device. If the closing element rests against one of the gear wheels in the manner of a stop in an open position of the closing device, this is associated with low production costs, since no separate stop is required. In a particularly advantageous embodiment, the closing surface of the scavenging channel can be designed as a sealing surface.

In addition, it is proposed that the closing device has a guide for guiding the opening and closing movements of the closing element. Such a guide increases the reliability of the locking device, since failures due to jamming or canting of the locking element can be avoided by the guide.

It has also proven to be advantageous if the fluid stream flows from an inlet to an outlet during conveying operation and from the outlet to the inlet during flushing operation. The flushing operation can be used in particular for flushing the gears, the gear space and other fluid-carrying components of the gear pump. The reversal of the fluid flow between the pumping operation and the flushing operation can be particularly advantageous Way are generated by reversing the direction of rotation of the gears. For this purpose, in particular, the drive unit can be switched from a forward run for the conveying operation to a reverse run for the flushing operation.

In connection with the fluid flow, it has turned out to be advantageous if the main flow component is greater than the secondary flow component. This enables efficient operation of the gear pump with low power losses and the fluid volume that can be pumped can be maximized. In addition, such a ratio between the main flow component and the secondary flow component can reduce the risk of leaks and leaks as well as other damage in the area of the secondary flow.

In terms of construction, it has proven to be advantageous if the gearwheel space has at least one compensation space for compensating for the squished volume of the gearwheels. The compensation space can advantageously serve to equalize pressure in the toothed area of the gear wheels. In particular, pressure peaks which arise in the fluid in the region of the mutually meshing gears can be reduced by such a compensation space. A reduction in pressure peaks leads to a reduction in the mechanical load on the components of the gear pump and in particular on the gears. In addition, the loads acting on the bearings of the gears can also be reduced in this way.

In this context, it is also preferred in terms of manufacturing technology if the compensation space is designed as a channel-like recess in a wall of the gearwheel space. The dimensions of the compensation chamber can be adapted to the squished volume of the gear wheels. It is particularly preferred if the compensation space is designed as a channel-like, rectangular recess is formed in the manner of a crush groove. Such a crushed groove can be manufactured in a particularly simple and quick manner. An arrangement of the compensation chamber on the wall of the gear wheel chamber, on which the outflow opening and the scavenging channel are also arranged, has proven to be particularly advantageous. On the one hand, this enables simple production and, on the other hand, favorable flow conditions within the gear space.

In this context, it has proven to be advantageous if the compensation space is arranged in a region of the gearwheel space in which the teeth of the gearwheels mesh with one another. This enables a direct flow connection between the squished volume of the gears and the compensation chamber. In this way, a reliable pressure equalization between the squeeze volume and the compensation space can be achieved.

From a structural point of view, it is advantageous if the end of the scavenging channel on the gearwheel side is flow-connected to the compensation chamber, in particular opens into it via the closing device. In this way, a flow connection can be formed between the end of the scavenging channel on the gear wheel side and the compensation chamber. This is advantageous in terms of efficient fluid flow. In addition, such a structural design has proven to be favorable in terms of manufacturing technology.

It is also proposed that the scavenging channel and/or the closing device have at least one orifice for flow connection to the compensation space. The orifice opening can have a larger flow cross section than the scavenging channel. Such an orifice advantageously enables a directed flow of the fluid; in particular, this allows the fluid to be introduced or discharged in a targeted manner into or out of the scavenging channel. Also enabled an orifice a flow connection between the gear space and the scavenging channel and/or the closing device even in the event that a tooth of the gear wheel covers the gear-side end of the smaller scavenging channel or the closing device when it is stationary.

In addition, it is proposed that the flow cross section of the scavenging channel is at least as large as the flow cross section of the outflow opening. In an advantageous embodiment, the flow cross section of the scavenging channel is larger than the flow cross section of the outflow opening. Such size ratios of the flow cross sections lead to an increase in the proportion of secondary flow in the flushing operation, as a result of which the flushing in the flushing operation can be improved. This always ensures that the fluid present in the adjacent space can flow through the scavenging channel into the gear space.

In an advantageous embodiment, the secondary flow portion flows in the scavenging operation along a secondary flow path, which leads via the outflow opening into the secondary space and out of the open scavenging channel and the annular gap into the gear space. Such a design of the secondary flow path enables a thorough flushing of the secondary space in the flushing operation due to a higher secondary flow portion of the overall fluid flow. This is particularly useful for applications in the food industry, such as in vending machines, in order to achieve hygienic cleanliness of the area of the gear pump through which the fluid flows.

With regard to a gear pump design that is as easy to assemble as possible, it has proven to be advantageous if it has a delivery unit having the gear wheels and a drive unit driving the gear wheels, which are detachably connected to one another via connecting elements that can be actuated without tools, the connecting elements are designed as locking elements. Such a design enables a particularly simple and assembly-friendly connection of the conveyor unit and the drive unit. Due to the design of the connecting elements as latching elements, the drive unit is connected to the conveyor unit in a simple and error-free manner. In a user-friendly manner, the latching elements allow precise and repeatable assembly with a constant connecting force, even after multiple loosening, which can also be carried out safely by inexperienced assembly personnel. Assembly errors, which could result, for example, from incorrect positioning of the connecting elements or insufficient connecting force, are avoided.

In an advantageous embodiment, it is proposed that connecting elements are arranged on the conveyor unit and connecting elements on the drive unit and are designed to correspond to one another. Such an arrangement enables a particularly simple and user-friendly connection or locking of the drive unit to the conveyor unit. It is particularly advantageous if the same number of connecting elements is formed on the conveyor unit and the drive unit. Furthermore, it is advantageous if the connecting elements on the conveyor unit and on the drive unit are designed to correspond in terms of their respective geometry. In addition, it has proven to be advantageous if the connecting elements are designed to correspond with respect to their respective position on the conveyor unit and the drive unit, which can result in a particularly simple possibility of connecting the drive unit to the conveyor unit. The connecting elements can be arranged directly on the conveyor unit and/or the drive unit. Alternatively, the connecting elements can also be arranged indirectly via an intermediate element on the conveyor unit and/or the drive unit. The intermediate element can be optional also have an adapter function, for example for arranging different drive units on one and the same conveyor unit.

In this context, it has proven to be particularly advantageous if the connecting elements are formed on sides of the conveyor unit and the drive unit that face one another. In this context, it can also be useful for connecting elements to be arranged on several sides of the conveyor and/or drive unit. This increases the flexibility with regard to the connection of the conveyor unit and drive unit with different alignments to one another.

An advantageous embodiment provides that connecting elements are formed on flat fastening areas of the conveyor unit and/or the drive unit. After locking the locking elements, there is a flat contact and thus a reliable connection.

Furthermore, it has turned out to be advantageous if the connecting elements are arranged at equal distances, in particular angular distances, relative to one another. Such an arrangement allows the conveyor unit and the drive unit to be connected to one another in a simple manner and is also advantageous with regard to a uniform transmission of forces between the conveyor unit and the drive unit. As a result, a particularly high-quality and firm connection can be achieved between the conveyor unit and the drive unit. In this context, it is particularly preferred if the connecting elements are arranged at equal distances relative to one another in the circumferential direction, as a result of which a particularly uniform connecting force can be generated.

It is also proposed that the connecting elements are designed in one piece with the conveyor unit and/or the drive unit. Such a Arrangement is particularly advantageous with regard to a simple connection, since the connecting elements are designed captive. Furthermore, such an embodiment is advantageous with regard to the production of the conveyor unit and/or the drive unit, for example by means of injection molding processes, since the connecting elements can be formed directly during the production of the conveyor unit and/or the drive unit.

In an advantageous development of the invention, it is proposed that the conveyor unit and the drive unit can be connected to one another in a number of assembly positions. Such a configuration enables a simple, user-friendly connection of the conveyor unit to the drive unit, since the conveyor unit and the drive unit can be connected to one another not just in one but in a number of assembly positions or orientations. It has also proven to be advantageous if the assembly positions differ with regard to the rotational alignment of the conveyor unit relative to the drive unit.

A further advantageous embodiment provides that the number of possible assembly positions corresponds to the number of corresponding connecting elements. An increased number of assembly positions can offer advantages with regard to the arrangement of the conveyor and drive unit. In particular, the accessibility to certain areas of the delivery unit and/or the drive unit can be improved in certain installation situations. Advantageously, two possible assembly positions can be provided for two pairs of connecting elements. Furthermore, with three pairs of connecting elements, three possible mounting positions can be provided, etc. It is particularly preferred if four mounting positions are provided and selectable with four pairs of connecting elements. Such a design enables the drive unit to be connected to the conveyor unit quickly and in a user-friendly manner, since it can already be determined from the number of pairs of connecting elements how many possible assembly positions there are.

In an advantageous development of the invention, it is proposed that the connecting elements form a bayonet connection. Such a bayonet connection is particularly advantageous with regard to a simple and error-free latching connection of the drive unit to the conveyor unit. Furthermore, a bayonet connection can enable the assembly personnel to have an intuitive, repeatable and non-destructively releasable latching connection of the drive unit to the conveyor unit. Establishing a connection via a bayonet connection can also be carried out easily and error-free for inexperienced assembly personnel.

In this context, it is proposed that the connecting elements are designed as bayonet hooks and/or corresponding recesses. Such an embodiment enables a bayonet connection to be produced in a simple manner. In particular, it is advantageous if the bayonet hooks are designed to engage in the corresponding recesses. In this context, it can be advantageous if the geometric configurations of the bayonet hooks and/or the recesses are adapted to one another or are designed to correspond.

In this context, it is also proposed that the bayonet hooks have an essentially rectangular shape with a base and a latching part that spreads out from the base at right angles. Such an arrangement allows a simple and assembly-friendly connection by means of the bayonet connection. In addition, the latching part that spreads out at right angles from the base can be used in a simple manner to produce a high-quality, form-fitting latching connection. As an alternative to the right-angled spread, you can also Querabspreizungen the locking part may be provided from the base in an angular range of 80 ° to 100 ° to the base.

In this context, it has proven to be structurally advantageous if the latching part points radially outwards or radially inwards.

It has also proven to be structurally advantageous if the recesses have an insertion area for inserting the bayonet hooks and a securing area for latching the bayonet hooks.

In this context, it is also proposed that the securing area for latching be designed to interact with the latching part of the bayonet hook. Such an embodiment enables a user-friendly connection between the drive unit and the delivery unit, which is reliable even if it is released several times, by means of a bayonet connection.

In a structurally advantageous embodiment, the recesses are designed as circular ring segments, with the plug-in areas extending over one half of the circular ring segments and the securing areas being arranged in the other half of the circular ring segments. It is preferred if the geometry of the plug-in areas is designed to correspond to the geometry of the bayonet hooks, and in particular the locking part of the bayonet hooks. Furthermore, such an arrangement can be advantageous with regard to user-friendly assembly of the conveyor unit and drive unit. The production of a bayonet connection can be made possible in an advantageous manner by sequentially inserting the bayonet hooks into the insertion area of the recesses and then rotating the bayonet hooks relative to the recesses. As a result, the locking part of the bayonet hook can be locked in a form-fitting manner with the securing area of the recesses. As an alternative to an extension over half of the circular ring segments, extensions can also be used be provided over a portion between 30% and 70% and in particular 40% and 60% of the width of the circular ring segments. In this context, adapted to the requirements of the connection between the conveyor unit and the drive unit, other geometric relationships, in particular wider or also less wide plug-in areas, are also conceivable.

In this context, it is also proposed that the securing areas extend flat and web-like from the outer radius of the circular ring segments in the radial direction over at least one third of the extent of the circular ring segments. As an alternative to extending over a third of the radial extent, the securing areas can also extend by 10% to 50% and in particular 25% to 45% of the radial extent of the circular ring segments.

In a development of the invention, it is proposed that the securing areas have a compensating ramp for tolerance compensation, which is designed to interact with the latching parts of the respective bayonet hooks. Such an embodiment enables tolerances to be compensated for and a play-free locking connection of the conveyor unit with the drive unit in a simple and advantageous manner. The compensating ramp is preferably designed in such a way that it can be reversibly deformed when tolerances overlap.

In this context, it is also preferred if the compensating ramp is arranged on the securing area as an inclined plane rising in the circumferential direction of the circular ring segment, which extends in particular over at least two thirds of the length of the securing area. Such a configuration of the compensating ramp enables a simple and user-friendly tolerance compensation. Depending on the relative position of the locking part of the bayonet hook to the compensation ramp of the security area, different tolerances can be compensated. The In this case, the inclined plane can have a constant rise angle or a rise angle that varies over the length of the compensating ramp. The individual security areas can have compensating ramps of the same design.

It is further proposed that the drive unit and the conveyor unit are designed to be rotatable relative to one another about an axis of rotation for fixing or releasing the bayonet connection. Advantageously, the drive unit and the conveyor unit can first be plugged into one another in the axial direction along the axis of rotation in the area of the connecting elements and, in a second step, rotated relative to one another about an axis of rotation. This allows a snap-in connection of the drive unit to the conveyor unit that can be established quickly and reliably even by inexperienced operating personnel. Furthermore, such a connection can be broken in a simple manner in a non-destructive manner by reversing the process steps carried out for the connection.

In this context, it is further proposed that the axis of rotation corresponds to the drive axis of the drive unit. This enables an axially symmetrical structure, in which case the drive unit and/or the conveyor unit can be rotated about the drive axis for connection. Advantageously, the connection can be made by turning in one direction of rotation and the connection can be released by turning in the opposite direction of rotation.

In a development of the invention, it is proposed that the conveyor unit has at least two bayonet hooks and the drive unit has at least two corresponding recesses for engaging the bayonet hooks. Such an arrangement is advantageous with regard to a simple connection between the delivery unit and the drive unit which is uniform in terms of the connection force. In this context it can alternatively, it can also be advantageous that the conveyor unit has at least two recesses and the drive unit has at least two corresponding bayonet hooks.

In a development of the invention, it is proposed that the conveyor unit has at least three, four or five bayonet hooks for connection to at least three, four or five corresponding recesses arranged on the drive unit. In this context, it is of particular advantage if the bayonet hooks and the corresponding recesses are arranged in a circle and evenly over the circumference. It is also easily conceivable that the conveyor unit has at least three, four or five recesses and the drive unit has at least three, four or five bayonet hooks for engaging in the recesses. A larger number of corresponding bayonet hooks and recesses has proven to be advantageous with regard to the mechanical strength of the connection.

In a development of the invention, it is also proposed that the bayonet connection has a reverse rotation lock. Such an embodiment is advantageous for securing against unintentional loosening of the connection. Furthermore, a reverse rotation lock can secure the delivery unit and the drive unit against an undesired loosening of the connection as a result of shocks and/or vibrations that can occur during operation of the gear pump. As a connection indicator, the anti-reverse device can also indicate a correct connection between the drive unit and the conveyor unit.

In this context, it has proven to be advantageous if the anti-reverse device has at least one spring-loaded safety hook, which interacts with at least one corresponding safety recess in a form-fitting manner. Such a configuration allows a simple and secure anti-twist device for the connection. It is particularly advantageous in this connection if the securing hook is designed to be resilient in the radial direction. Furthermore, the securing recess can advantageously be adapted to the structural design of the securing hook in terms of its position and geometric shape.

In this context, it is also proposed that the safety hook has a safety lug for engaging in a corresponding safety recess. Such a safety lug allows a simple and effective reverse rotation lock. In particular, it can be advantageous if the geometry of the securing lug is adapted to the geometry of the corresponding securing recess.

In this context, it has proven to be structurally advantageous if the at least one securing hook is arranged on the conveyor unit and the at least one securing recess is arranged on the drive unit. With such an arrangement, the conveyor unit and the drive unit can be secured in a simple and reliable manner against unintentional turning back and thus against unintentional loosening of the connection. It is also conceivable in this connection for the drive unit to have a safety hook, which is designed to interact with at least one safety recess arranged on the conveyor unit to prevent reverse rotation.

In this context, it is also proposed that the anti-reverse device has a safety hook and a plurality of safety recesses, in which the safety hook can engage depending on the mounting position. Such an arrangement enables the conveyor unit and the drive unit to be connected in a number of assembly positions, and these can be secured against unintentional turning back. As it has proven to be advantageous if the drive unit has at least two, preferably four and particularly preferably as many securing recesses around the circumference as there are connecting elements on the drive unit or on the conveyor unit. Furthermore, it is easily conceivable that the conveyor unit can have a plurality of securing recesses distributed over the circumference of the fastening area.

A further advantageous alternative embodiment provides that the connecting elements form a snap hook connection. Such a configuration, like a bayonet connection, enables a simple and user-friendly latching connection of the drive unit to the conveyor unit.

In this context, it is proposed that the connecting elements be designed as resilient latching tongues and/or corresponding recesses. In particular, the latching tongues can be designed in such a way that they can be inserted in a form-fitting manner into the corresponding recesses. With regard to a simple connection, it has proven to be advantageous if the latching tongues are designed to be radially resilient.

In this context, it is also proposed that the latching tongues have a latching area which is designed to interact in a form-fitting manner with a corresponding latching area of the recesses. Such a construction allows a simple and error-free latching connection between the conveyor unit and the drive unit. The latching connection can be created by simply inserting the latching tongues into the corresponding recesses.

In addition, it is proposed that the latching tongues have an insertion bevel for easy insertion into the recesses. This achieves a user-friendly design of the latching tongues. In this case, the insertion bevel can be designed as an inclined plane extending from the tip of the latching tongues in their axial direction. The edge of the recesses can be designed to interact with the insertion bevel and support a deflection of the latching tongues.

It is also proposed that the latching tongues be designed in such a way that when they are inserted, they compress the recesses transversely to their insertion direction and spring out when the connection position is reached, as a result of which the latching areas latch with one another. Such a construction is advantageous with regard to a simple connection of the drive unit to the delivery unit by plugging in in the axial direction. Furthermore, the latching areas latched to one another can also serve as an indicator of a successful connection of the delivery unit to the drive unit. For this purpose, the latching tongues can have markings of a different color, in particular at their tip, as a connection indicator, which are arranged visibly when latched correctly and indicate a successful connection. Assembly errors can be avoided in this way.

In this context, it is also proposed that the latching tongues be designed in such a way that they deflect transversely to the direction of insertion when a releasing force applied counter to the direction of insertion is reached. Such a design enables the connection to be released easily. By applying the releasing force, the locking can be canceled in a simple manner. In a particularly advantageous manner, the releasing force to be applied for releasing is selected in such a way that it cannot easily occur during operation of the gear pump, as a result of which an unintentional release of the snap hook connection during operation can be prevented.

It is further proposed that the conveyor unit has at least two latching tongues and the drive unit has at least two corresponding recesses for engaging the latching tongues. This has proven to be advantageous with regard to a safe, symmetrical and resilient connection between the conveyor unit and the drive unit. In this connection it is also conceivable that the drive unit has at least two locking tongues and the conveying unit has at least two corresponding recesses for engagement of the locking tongues.

It has also proven to be advantageous if the conveyor unit has three, four or five latching tongues for connection to three, four or five corresponding recesses arranged on the drive unit. Such an arrangement is of particular advantage for the mechanical strength of the connection between the conveyor unit and the drive unit. It is particularly advantageous if the three, four or five locking tongues or the three, four or five corresponding recesses are arranged in a circle at a uniform distance from one another on the respective fastening area. It is also easily conceivable that the drive unit can have three, four or five latching tongues for connection to three, four or five corresponding recesses arranged on the conveyor unit.

In a development of the invention, guide elements are proposed for guiding the plug-in movements when connecting and/or releasing the snap hook connection. Such guide elements can simplify the production of the locking connection between the conveying element and the drive element. Furthermore, such guide elements can serve as protection against incorrect assembly. It is particularly advantageous if the guide elements are designed as projections or recesses and have shapes that correspond to one another.

It can also be advantageous if the connecting elements are formed on at least one intermediate element, with the intermediate element being fastened to the conveyor unit and/or the drive unit. When using such an intermediate element, the connecting elements are indirectly connected to the drive unit and/or the conveyor unit via the intermediate element. The intermediate element can be adapted to the requirements of the connection between the conveyor unit and the drive unit in the manner of an adapter. Different drive units and conveyor units can therefore also be connected to one another by using different intermediate elements. This can be an advantage, for example, when replacing a less powerful drive unit with a more powerful one. The intermediate element can be designed in the manner of a disk. In this context, it has proven to be advantageous if connecting elements are arranged in one piece on the conveyor unit and corresponding connecting elements are formed on an intermediate element, which is arranged on the drive unit. It has also proven to be advantageous if the intermediate element is detachably attached to the conveyor unit and/or the drive unit. In particular, a detachable attachment by means of attachment means such as screws or bolts may be preferred. Such an arrangement can enable the intermediate element to be changed easily and quickly. Furthermore, the intermediate element can thus be exchanged in a simple manner. However, the intermediate element can also be non-detachably fastened to the conveyor unit and/or the drive unit if this turns out to be advantageous for the respective application.

It has proven to be advantageous if the intermediate element has a shaft bearing for supporting the intermediate shaft. Such an arrangement enables reliable mounting of the intermediate shaft in a simple manner. The shaft bearing is preferably in the middle and after Kind of a cylindrical collar formed on a substantially disc-shaped intermediate element. Together with the plain bearing arranged in the area of the conveyor unit, a two-point bearing of the intermediate shaft can advantageously result.

In an advantageous embodiment, the intermediate shaft has an actuating contour which can be positively connected to a corresponding actuating contour arranged on at least one of the gearwheels. In this way, the intermediate shaft and the gear wheel can be connected to one another in a simple and user-friendly manner. This gear is the driven gear.

It is also proposed that at least one of the gears has a bearing contour for freely rotatable arrangement on a bearing axle. Such a bearing contour has proven to be advantageous for mounting the gear wheel on the bearing axle. This gear is the co-rotating gear.

In this context, it is further proposed that the actuating contours can be connected to one another in a form-fitting manner. In particular, it is advantageous if the actuating contour of the intermediate shaft is designed to correspond to the actuating contour of at least one of the gearwheels and can be connected to it in a form-fitting manner. Such a configuration enables a simple form-fitting connection of the intermediate shaft to at least one of the gears. It is particularly advantageous if the driven gear wheel of the gear pump has an actuating contour.

In addition, it is proposed that the actuating contour of the intermediate shaft should not be designed so that it can be inserted into the bearing contour. Such a configuration allows the intermediate shaft not to be connected to the non-driven gear wheel, which has the bearing contour can. This also makes it possible to avoid assembly errors, since the intermediate shaft can only be connected to the driven gear provided for this purpose.

It is proposed that the actuating contours be designed in the manner of a polygon, in particular a pentagon. Such a configuration has proven to be advantageous with regard to low-loss power transmission. Furthermore, a polygon can be produced in a simple manner. In particular, a polygon can be designed as the outer contour of a bolt or as the inner contour of a bore.

In this context, it has proven to be advantageous if the bearing contour is designed as a round bore. Such a round bore allows a simple, freely rotatable mounting of the non-driven gear wheel on the bearing axle.

With regard to simple assembly, it is advantageous if the diameter of the round bore and the diameter of the polygon of the actuating contour are selected in such a way that they cannot be plugged into one another. This enables the gear pump to be assembled in a simple and error-free manner. Assembly errors due to incorrect connection of the intermediate shaft and/or the bearing axle to the gears can be prevented.

In addition, it is proposed that the conveyor unit has a sliding bearing for supporting the intermediate shaft of the drive unit. In this context, it has proven to be advantageous if the sliding bearing is arranged in the vicinity of the driven gear. Such a constructive arrangement can reduce friction and wear, since angular errors between the intermediate shaft and the gear can be compensated for by the slide bearing.

It has proven to be structurally advantageous if the gears are arranged in a gear space delimited by a wall of the conveyor unit and the plain bearing is arranged in the wall. In such an embodiment, the plain bearing is in close proximity to the gears. Angular errors are effectively compensated.

It is also proposed that the gear pump has a connection indicator showing the connection between the delivery unit and the drive unit. With correct latching, this connection indicator can be arranged so that it is visible to the assembly personnel and can indicate a successful connection. Assembly errors can be avoided in this way.

In this context, it is structurally proposed that the connection indicator is formed on the anti-reverse lock of the bayonet connection and/or on the latching tongue of the snap hook connection.

In addition, a pump arrangement with a gear pump and at least one valve unit is proposed to solve the task mentioned above, wherein the gear pump is designed according to one or more of the features described above. The same advantages mentioned above in relation to the gear pump result in connection with the pump arrangement. Such a pump arrangement advantageously enables the fluid flow to be controlled.

In a development of the pump arrangement, it is proposed that the delivery unit of the gear pump be connected to a valve unit via connecting elements that can be actuated without tools. Such a design enables a quick and user-friendly connection between the delivery unit and the valve unit.

In this context, it has proven to be advantageous if the connecting elements are designed as latching elements. This results in the same advantages that have already been explained above with regard to the connection between the conveyor unit and the drive unit.

It is particularly preferred if the connecting elements form a bayonet connection. In particular, it is advantageous if the bayonet connection is designed in accordance with the bayonet connection described above.

Alternatively, the connecting elements can also form a snap hook connection. In particular, it is advantageous if the snap hook connection is designed in accordance with the snap hook connection described above.

Furthermore, a method according to patent claim 15 is proposed to solve the above-mentioned problem. In connection with the method, the same advantages arise as previously mentioned in relation to the gear pump and/or pump arrangement. In particular, such a method enables thorough rinsing of the adjoining space during the rinsing operation.

In connection with the method mentioned above, it is proposed that the gear pump and/or the pump arrangement be designed according to one or more of the features described above.

Fig. 1 und 2

perspektivische Ansichten einer erfindungsgemäßen Zahnradpumpe gemäß einer ersten Ausführungsform;

Fig. 3

eine Schnittdarstellung der Zahnradpumpe gemäß der Darstellung in Fig. 2;

Fig. 4

eine perspektivische Explosionsansicht der Zahnradpumpe gemäß Fig. 3;

Fig. 5

einen Querschnitt der Zahnradpumpe im Bereich der Fördereinheit;

Fig. 6a bis 6c

perspektivische Ansichten der Zahnräder sowie einer Zwischenwelle der Zahnradpumpe;

Fig. 7

eine schematische Darstellung der Betätigungs- und Lagerkontur;

Fig. 8a

eine perspektivische, teilweise geschnittene Ansicht einer Zahnradpumpe;

Fig. 8b

eine vergrößerte Ansicht der in Fig. 8a mit VIII b bezeichneten Einzelheit;

Fig. 9a bis 9e

perspektivische Ansichten der Bajonettverbindung einer Zahnradpumpe;

Fig. 10 und 11

perspektivische Ansichten zur Veranschaulichung des Toleranzausgleichs der Bajonettverbindung einer Zahnradpumpe;

Fig. 12a

eine Schnittansicht der Bajonettverbindung gemäß Fig. 10;

Fig. 12b

eine Schnittansicht gemäß der in Fig. 12a mit XII b bezeichneten Einzelheit;

Fig. 13

eine perspektivische Detailansicht der Bajonettverbindung gemäß Fig. 11;

Fig. 14

eine weitere perspektivische Detailansicht der Bajonettverbindung gemäß Fig. 11;

Fig. 15 bis 17

perspektivische Ansichten einer Zahnradpumpe gemäß einer zweiten Ausführungsform;

Fig. 18 bis 20

Detailansichten der Schnapphakenverbindung der Zahnradpumpe gemäß Fig. 15 bis 17;

Fig. 21 bis 23

perspektivische Ansichten verschiedener Pumpanordnungen mit einer Zahnradpumpe und mehreren Ventileinheiten;

Fig. 24a und b

Querschnitte der Zahnradpumpe im Bereich des Zahnradraums mit Richtungspfeilen zur Veranschaulichung der Drehrichtung der Zahnräder sowie der Strömungsrichtung im Förder- sowie Spülbetrieb;

Fig. 25

einen Längsschnitt der Zahnradpumpe im Bereich der Fördereinheit;

Fig. 26

eine teilweise geschnittene Ansicht der Zahnradpumpe im Bereich der Fördereinheit;

Fig. 27

in einem weiteren Längsschnitt durch die Fördereinheit eine vergrößerte Detailansicht;

Fig 28a

eine teilweise geschnittene Ansicht der Fördereinheit im Förderbetrieb;

Fig. 28b

eine vergrößerte Detailansicht der in Fig. 28a mit XXVIII b bezeichneten Einzelheit mit einer stark vereinfachten, schematischen Darstellung der Fluidströmung im Förderbetrieb;

Fig 29a

eine teilweise geschnittene Ansicht der Fördereinheit im Spülbetrieb;

Fig. 29b

eine vergrößerte Detailansicht der in Fig. 29a mit XXIX b bezeichneten Einzelheit mit einer stark vereinfachten, schematischen Darstellung der Fluidströmung im Spülbetrieb;

Fig. 30a und b

perspektivische Ansichten des Zahnradraums der Zahnradpumpe;

Fig. 31a und b

Detailansichten des Zahnradraums gemäß den Darstellungen in Fig. 30a und b; und

Fig. 32

eine teilweise transparente Frontalansicht des Zahnradraums.

Further details and advantages of the invention are explained below with the aid of the accompanying drawings of exemplary embodiments. However, the invention is not limited to these exemplary embodiments. Further exemplary embodiments can be combined with one another by combining the features of one or more of the features described above and/or with one or more features of the exemplary embodiments or claims. In the drawings show:

Figures 1 and 2

perspective views of a gear pump according to the invention according to a first embodiment;

3

a sectional view of the gear pump as shown in FIG 2 ;

4

an exploded perspective view of the gear pump according to FIG 3 ;

figure 5

a cross section of the gear pump in the area of the delivery unit;

Figures 6a to 6c

perspective views of the gears and an intermediate shaft of the gear pump;

7

a schematic representation of the actuation and storage contour;

Figure 8a

a perspective, partially sectioned view of a gear pump;

Figure 8b

an enlarged view of the in Figure 8a item marked VIII b;

Figures 9a to 9e

perspective views of the bayonet connection of a gear pump;

Figures 10 and 11

perspective views to illustrate the tolerance compensation of the bayonet connection of a gear pump;

12a

a sectional view of the bayonet connection according to FIG 10 ;

Figure 12b

a sectional view according to FIG 12a item marked XII b;

13

a detailed perspective view of the bayonet connection according to FIG 11 ;

14

a further detailed perspective view of the bayonet connection according to FIG 11 ;

Figures 15 to 17

perspective views of a gear pump according to a second embodiment;

Figures 18 to 20

Detailed views of the snap hook connection of the gear pump according to Figures 15 to 17 ;

Figures 21 to 23

perspective views of different pump arrangements with a gear pump and several valve units;

Figures 24a and b

Cross-sections of the gear pump in the area of the gear chamber with directional arrows to illustrate the direction of rotation of the gear wheels and the direction of flow in pumping and flushing operation;

25

a longitudinal section of the gear pump in the area of the delivery unit;

26

a partially sectioned view of the gear pump in the area of the delivery unit;

27

in a further longitudinal section through the conveyor unit, an enlarged detail view;

Figure 28a

a partially sectioned view of the conveying unit in conveying operation;

Figure 28b

an enlarged detailed view of the in 28a with XXVIII b designated detail with a greatly simplified, schematic representation of the fluid flow in the pumping operation;

Figure 29a

a partially sectioned view of the conveyor unit in the flushing mode;

Figure 29b

an enlarged detailed view of the in Figure 29a with XXIX b designated detail with a greatly simplified, schematic representation of the fluid flow in the flushing operation;

Figures 30a and b

perspective views of the gear chamber of the gear pump;

Figures 31a and b

Detailed views of the gear space according to the illustrations in Figure 30a and b; and

32

a partially transparent frontal view of the gear room.

The depictions in the 1 and 2 show a gear pump 1 with a delivery unit 2 for delivering a fluid and a drive unit 3 designed as an electric motor. The drive unit 3 is used to operate the delivery unit 2, which, via two connections 26 serving as inlet and outlet, from the fluid to be delivered, in which it e.g. drinking water, milk, coffee or similar. can act, can be flowed through.

As will be explained in detail below, the gear pump 1 is characterized by good hygienic properties both in the conveying and in the rinsing operation and can be assembled in a particularly easy-to-assemble manner.

First, based on the representation in the Figures 1 to 23 especially the assembly of the gear pump 1 will be discussed.

The drive unit 3 is detachably connected to the conveyor unit 2 . For this purpose, several connecting elements 7, 8 are provided. The connecting elements 7, 8 are designed as locking elements and therefore allow a simple and error-free locking connection of the conveyor unit 2 and the drive unit 3.

The latching elements 7, 8 face one another and act together in a latching manner in the manner of a bayonet connection 50, cf. 2 . Details of the bayonet connection 50 are based on the representations in the 9a to 14 be explained in more detail.

The connecting elements 7 are arranged on an end face of the conveyor unit 2 and interact with the connecting elements arranged on the drive unit 3 8 latching together. While the connecting elements 7 are arranged directly on the conveyor unit 2 , the connecting elements 8 are arranged indirectly on the drive unit 3 via a disc-shaped intermediate element 6 . The indirect arrangement of the connecting elements 8 on the drive unit 3 has the advantage that the intermediate element 6 can be used as an adapter for connecting different drive units 3, e.g.

Alternatively, it would also be conceivable for the connection elements 8 on the drive side to be arranged directly on the drive unit 3 . It would also be conceivable for the connecting elements 7 to be formed on an intermediate element, which is not shown in the figures and is connected to the conveyor unit 2 .

While the representation in 1 shows a disconnected state, shows the representation in 2 the mounted gear pump 1, in which the drive unit 3 and the delivery unit 2 are detachably connected to one another via the bayonet connection 50 by mutual latching. In the assembled state, the end faces of the conveyor unit 2 and the intermediate element 6 of the drive unit 3 lie flush and flat against one another and form a connection area 5.

Details of the drive unit 3, the intermediate element 6 and the conveyor unit 2 are described below, in particular with reference to the illustrations in FIGS Figures 3 and 4 explained.

The drive unit 3 of the gear pump 1 has a substantially cylindrical geometry and is designed as an electric motor. The drive unit 3 has electrical connections 3.1. By energizing the drive unit 3, a drive shaft 3.2 is set in rotation, which is used to drive the conveyor unit 3.

In the exemplary embodiment, the drive unit 3 is a commercially available standard electric motor in a wide variety of designs, such as brushless or brushed electric motors of different power classes. In order to transmit the rotational movement of the drive unit 3 generated by the drive unit 3 to the conveyor unit 2 , an intermediate shaft 14 extending between the drive 3 and the conveyor unit 2 is provided. In the exemplary embodiment, the intermediate shaft 14 is designed as a separate component. On one side, the intermediate shaft 14 is connected to a drive shaft 3.2, designed as a short stub axle, of the drive unit 3 and on the other side to the conveyor unit 3. Alternatively, it would also be conceivable for the intermediate shaft 14 to be connected in one piece to the drive shaft 3.2. In this case, however, a standard motor could not be used.

As is shown, for example, in the illustration in 4 becomes clear, the intermediate shaft 14 has a shaft connection 14.2 for connection to the drive unit 3. The shaft connection 14.2 is cylindrical and sleeve-like and is an integral part of the intermediate shaft 14. The shaft connection 14.2 is pressed onto the drive shaft 3.2 for connection to the drive unit 3. The intermediate shaft 14 can in particular be made of stainless steel with a minimum chrome content of 16%, which is approved for use in the food sector or for driving gear pumps 1 for pumping drinking water. The drive shaft 3.2 of the drive unit 3 does not come into contact with the fluid to be pumped due to the intermediate shaft 14 pressed on in the manner of a shaft extension.

On one end face, the drive unit 3 has a disc-shaped intermediate element 6 which is releasably attached to the drive unit 3 by means of fastening means 23 designed as screws and corresponding bores 24 . The intermediate element 6 is essentially round. The intermediate element 6 has the drive-side connecting elements 8 which are recesses 8 . In addition, the intermediate element 6 has a shaft bearing 13 for supporting the intermediate shaft 14 . The shaft bearing 13 is designed in the manner of a cylindrical collar and extends in the center of the intermediate element 6 essentially perpendicularly to its surface.

The conveyor unit 2 is essentially cuboid and has a housing 2.1 and a cover 2.2, which are connected to one another by means of cylindrical plug-in connection elements 22 shaped like dumbbells. The plug-in connection elements 22 are inserted into correspondingly designed recesses 33 for connection and overlap the planar contact area between the housing 2.1 and the cover 2.2 on its underside and upper side, see also FIG 4 and 9a . The cover 2.2 has two tubular connections 26 serving as inlet and outlet, via which the delivery unit 2 can be connected to other, not shown, components of the respective hydraulic system. On the side opposite the connections 26, the delivery unit 2 has a flat fastening area B, on which the connecting elements 7 are formed in one piece. The connecting elements 7 are as shown in 1 designed as a bayonet hook. In the present exemplary embodiment, the bayonet hooks 7 are arranged directly on the fastening area B. Alternatively, however, it is also conceivable for these to be arranged indirectly on the fastening area B via an intermediate element 6 . An inverse arrangement would also be conceivable, ie arranging the bayonet hooks 7 on the drive side and the recesses 8 on the conveying side.

The housing 2.1 and the cover 2.2 of the conveyor unit 2 as well as the intermediate element 6 and all elements arranged on it are preferably made of plastic by means of suitable methods, in particular injection molding methods. All components that come into contact with the fluid to be pumped are suitable for use in the food or drinking water sector and in particular for use in vending machines.

Below is the arrangement of the gears 4.1 and 4.2 in the conveyor unit 2 and their drive based on the illustrations in the Figures 3 to 7 explained in more detail.

A gear space 35 is arranged inside the housing 2.1. The gear space 35 is sealed off from the cover 2.2 by means of a seal 25 designed as an O-ring. In the gear space 35 two gears 4.1 and 4.2 are rotatably arranged. The teeth of the driven gear 4.1 engage in the corresponding gaps in a second co-rotating gear 4.2. The co-rotating gear 4.2 is rotatably mounted parallel to the axis of the driven gear 4.1 on an axle 21 arranged in the housing 2.2. Both gears 4.1, 4.2 are flowed around by the fluid to be pumped. A rotating movement of the driven gear wheel 4.1 causes the co-rotating gear wheel 4.2 to rotate in the opposite direction. This creates a pressure gradient that can be used to convey the fluid, over which the fluid flows from an inlet 31 to an outlet 32 . The connections 26 are connected to the inlet 31 and the outlet 32 and can be guided through the cover 2.2 or arranged on the lateral walls of the housing 2.1.

The driven gear wheel 4.1 is plug-connected to the intermediate shaft 14 for driving the conveyor unit 2. The drive force is transmitted from the intermediate shaft 14 to the driven gear wheel 4.1 via corresponding actuating contours 14.1 and 16.1. In the present embodiment the actuating contour 14.1 is designed as a pentagon, which is arranged as an outer contour on the end of the intermediate shaft 14 opposite the drive unit 3, cf. Figure 6c . The driven gear wheel 4.1 has a corresponding pentagonal contour, designed as an inner contour, as the actuating contour 16.1, cf. Figure 6b . The actuating contour 14.1 is inserted into the actuating contour 16.1 to drive the driven gear wheel 14.1. The design as a pentagon enables the torque to be transmitted effectively.

In order to prevent a possible incorrect assembly of the intermediate shaft 14 on the co-rotating gear wheel 4.2, the co-rotating gear wheel 4.2 has no actuating contour, but rather a bearing contour 16.2 designed as a round bore, cf. Figure 6a . The geometries of the actuating contour 14.1 and the bearing contour 16.2 are selected in such a way that the actuating contour 14.1 of the intermediate shaft 14 cannot be inserted into the bearing contour 16.2 of the co-rotating gear wheel 4.2, cf. 7 . This ensures that the intermediate shaft 14 can only be connected to the driven gear 4.1. The bearing contour 16.2 is designed in such a way that the co-rotating gear wheel 4.2 can only be connected to the corresponding axle 21 provided for this purpose, see also FIG Figure 8b .

A shaft sealing ring 15 is provided to seal the intermediate shaft 14 from the gear chamber 35 through which fluid flows, which is arranged in the housing 2.1 of the delivery unit 2, cf. 4 . In the present exemplary embodiment, the shaft sealing ring 15 is designed as a radial shaft sealing ring. In order to achieve the hardness of the intermediate shaft 14 of at least 45 HRC required for sealing with the shaft sealing ring 15, the intermediate shaft 14 has a corresponding coating in the area of the shaft sealing ring 15 or has been hardened to the corresponding hardness specification by means of Kolsterizing. To reduce the risk of damage to the shaft seal To prevent 15 during assembly, the edges of the operating contour 14.1, which is designed as a pentagon, are rounded.

Based on the illustrations in the Figures 8a and 8b the storage of the gears 4.1 and 4.2 in the conveyor unit 2 is explained below. Figure 8b shows an enlargement of section VIII b according to FIG Figure 8a .

As previously explained, the driven gear wheel 4.1 is slipped onto the actuating contour 14.1 of the intermediate shaft 14. A sliding bearing 17 is arranged in a passage 114 of the housing 2.1 of the conveyor unit 2 in the immediate vicinity of the gear wheel 4.1. The arrangement of the sliding bearing 17 in the wall 2.3 of the conveyor unit 2 in the vicinity of the gear wheel 4.1 enables additional guidance of the intermediate shaft 14 in the manner of a two-point bearing. The slide bearing 17 can be designed as a recess in the wall 2.3, provided the wall is made of a suitable material. Alternatively, the plain bearing 17 can be used as a separate component in the wall 2.3 and be designed, for example, as a plain bearing bush. The possible effects of angular offsets, for example due to angular tolerances of the drive unit 3, which become greater the greater the distance from the plain bearing 17, can be reduced in the area of the gear wheel 4.1. This enables the gear pump 1 to run smoothly, which can also reduce the wear on the gear wheels 4.1 and 4.2. In a similar way, the axis 21 of the co-rotating gear wheel 4.2 is also mounted in the area of this gear wheel 4.2 by means of a plain bearing. The slide bearing of the co-rotating gear 4.2 can also be used in one piece on the gear 4.2 or as a separate slide bearing in this.

The following is based on the representations in the 9a to 14 the configuration of the bayonet connection 50 provided in the first exemplary embodiment is explained.

The representation in Figure 9a shows the fastening area B arranged on one side of the conveyor unit 2. Four bayonet hooks 7 are arranged at a certain radial distance from the center point of the fastening area B. FIG. The bayonet hooks 7 are arranged point-symmetrically to a central round bore of the fastening area B at regular intervals, so that there is an angle of 90° between the bayonet hooks 7 in each case. The bayonet hooks 7 are formed in one piece with the housing 2.1. Based on the representation in 14 it can be seen that the bayonet hooks 7 are essentially L-shaped with a rectangular base and have a base 7.1 and a latching part 7.2. The base 7.1 extends perpendicularly from the surface of the attachment area B. At a certain distance from the surface of the attachment area B, the latching part 7.2 extends transversely to the base 7.1. The lower edge of the latching part 7.2 extends parallel to the surface of the fastening area B. The outer edges of the bayonet hook 7 are beveled or have chamfers, which can facilitate insertion into the corresponding recesses 8.

As explained, the intermediate element 6 fastened to the drive unit 3 in the present exemplary embodiment is designed in the manner of a flat round disk, cf. Figure 9b . The intermediate element 6 has four continuous recesses 8 which are designed in the manner of circular ring segments 34 . The recesses 8 are designed in such a way that they can interact with the bayonet hooks 7 to connect the delivery unit 2 to the drive unit 3 . The recesses 8 are arranged point-symmetrically on a common circular path around a central round bore. The angular spacing of the recesses is accordingly 90°.

The recesses 8 each have a plug-in area 8.1, cf. 10 . This plug-in area 8.1 is adapted to the geometry of the latching part 7.2 of the bayonet hook 7 and enables the bayonet hook to be plugged in 7. The plug-in area 8.1 extends in the circumferential direction over approximately half the circumferential length of the recess 8. In the other half of the circumference of the recess 8 there is a securing area 8.2. This securing area 8.2 is designed to interact with the latching part 7.2 of the bayonet hook 7. It extends flat and web-like from the outer radius of the recess 8 to about one third of its radial length, cf. 10 . The securing area 8.2 is arranged in the lower area of the recess 8; its thickness corresponds to approximately half the thickness of the intermediate element 6, cf. 12a . The recesses 8 have bevels for easy connection to the bayonet hooks 7 .

In order to establish the connection by means of the bayonet connection 50, the conveyor unit 2 and the drive unit 3 are configured such that they can be rotated relative to one another, with the axis of rotation D corresponding to the drive axis A, see also FIG 3 . As a result of the mutual twisting, the securing area 8.2 of the recess 8 and the latching part 7.2 of the bayonet hook 7 come into mutual engagement, cf. 12a . No additional tools are required to produce the bayonet connection 50 . In the connected state according to 11 the four bayonet hooks 7 grip behind the securing areas 8.2 of the recesses 8, as a result of which they are locked in a form-fitting manner.

In order to prevent the connection from being released unintentionally or accidentally, the bayonet connection 50 has a reverse rotation lock 10 for securing against reverse rotation. In particular, the anti-reverse device 10 serves to secure against undesired loosening due to vibrations or shocks during operation of the gear pump 1. For this purpose, the delivery unit 2 has a safety hook 10.1, cf. Figure 9a . The securing hook 10.1 is arranged radially on the outside of the fastening area B and is designed as a spring arm which is articulated on one side and is resilient in the radial direction. Furthermore, the safety hook 10.1 has a projecting safety lug 10.2 on, which extends at the free end of the safety hook 10.1 essentially perpendicular to the surface of the fastening area B. In the correctly assembled state, the securing lug 10.2 engages in a correspondingly designed recess 10.3 of the intermediate element 6, cf. Figures 9d and 9e . To release the bayonet connection 50, the safety hook 10.1 can be manually disengaged from the recess 10.3. Alternatively or additionally, a releasing force sufficient to release the bayonet connection 50 can be generated by mutually rotating the delivery unit 2 relative to the drive unit 3 .

The reverse rotation lock 10 has a dual function. It not only serves to avoid unintentional loosening, but also shows a correctly latched bayonet connection 50 between the conveyor unit 2 and the drive unit 3 as a connection indicator 36 that can be read from the outside. Only when the bayonet connection 50 is correctly engaged are the securing lug 10.2 visible from the outside and the recess 10.3 engaged with one another.

In the exemplary embodiment, the intermediate element 6 has a total of four recesses 10.3, which are arranged at equal distances over the circumference of the intermediate element 6, cf. Fig. 9e . One securing lug 10.2 can engage in any of these recesses 10.3. Thus, the drive unit 3 can be connected to the conveyor unit 2 in any four orientations or assembly positions, which differ in the rotational position of the drive unit 3 about its drive axis A.

Furthermore, the securing areas 8.2 each have a compensation ramp 9 for tolerance compensation. The compensating ramp 9 is designed in such a way that it can interact with the latching part 7.2 of the corresponding bayonet hook 7. The compensating ramp 9 is about two thirds of the length of the Securing area 8.2 arranged in the circumferential direction on this and essentially covers its entire width in the radial direction. The compensating ramp 9 is designed as an inclined plane that rises in the circumferential direction and, in the installed state, extends in the direction of the latching part 7.2 of the bayonet hook 7, see also FIG Figure 12b . Together with the locking part 7.2 of the bayonet hook 7, the compensating ramp 9 can be used to compensate for tolerances and ensure a play-free connection between the conveyor unit 2 and the drive unit 3. For this purpose, the compensating ramp 9 is designed in such a way that it can be reversibly deformed if there is a tolerance overlap.

The depictions in the Figures 15 to 20 show a second embodiment which, in contrast to the first embodiment, does not have a bayonet connection 50, but rather a snap hook connection 60, but which otherwise corresponds to all relevant features of the first embodiment.

The snap hook connection 60 differs from the bayonet connection 50 described above essentially in the structural design of the connecting elements 11, 12.

The representation in 15 1 shows a fastening area B arranged on one side of the conveyor unit 2. Four recesses 12 are arranged at a certain radial distance from the center point of the fastening area B. FIG. The recesses 12 are arranged at equal intervals and tangentially to a central round bore of the fastening area B, so that there is an angle of 90° between the recesses 12 in each case. The recesses 12 are designed as essentially rectangular openings in the attachment area B, cf. 19 . The recesses 12 each have a latching area 12.1, which is arranged in the manner of an edge on the back of the fastening area B, see also FIG 20 . Between the recesses 12 are more, also rectangular openings on the attachment area B arranged. Furthermore, the fastening area B has four guide elements 20, which are arranged as rectangular recesses designed in the manner of notches on the edge of the central round bore. The guide elements 20 are aligned with the recesses 12.

Similar to the first embodiment, four latching tongues 11 of the snap hook connection 60 are formed on an intermediate element 6, cf. 18 . The latching tongues 11 have a tab-like basic shape and extend essentially transversely to the surface of the intermediate element 6 in the same direction as the shaft bearing 13 designed as a cylindrical collar. The latching tongues 11 are designed to be resilient in the radial direction like a resilient cantilever. The four latching tongues 11 are arranged at a uniform distance from one another on the same radius, so that they are aligned with the recesses 12 of the conveyor unit 2 to produce a latching connection, cf. 16 . In the region of their tip, the latching tongues 11 have a latching area 11.1, which is designed like an edge transversely to the tab-like base body of the latching tongue 11. The tip of the latching tongues 11 is provided with an insertion bevel 11.2, by means of which the insertion of the latching tongues 11 into the corresponding recesses 12 of the conveyor unit 2 can be facilitated. Furthermore, the intermediate element 6 has four guide elements 19 which are designed as rectangular, nose-like projections on the cylindrical collar of the shaft bearing 13 . The guide elements 19 are aligned with the latching tongues 11.

To produce the snap hook connection 60, the drive unit 3 is moved in the insertion direction R along the drive axis A toward the conveyor unit 2 and inserted into the recesses 12, cf. Figures 15 and 16 . When plugging in, the tips of the latching tongues 11 abut the edges of the corresponding recesses 12 in the area of the fastening area B.

As a result, the spring-loaded latching tongues 11 deflect in the radial direction. The chamfers 11.2 facilitate insertion. Upon reaching the connection position according to 17 the locking tongues 11 spring out transversely to the lancing direction R, with the locking areas 11.1 of the locking tongues 11 locking with the locking areas 12.1 of the recesses 12, see also FIG 20 . The delivery unit 2 and the drive unit 3 are thus locked together in the axial direction. Since the recesses 12 essentially have the same width as the tab-like latching tongues 11, a relative rotation of the drive unit 3 with respect to the conveyor unit 2 is also blocked. No additional tools are required to produce the snap hook connection 60 .

In the connection position, the correspondingly designed guide elements 19, 20 of the intermediate element 6 and the fastening area B also engage in one another. This enables additional security against relative rotation of the conveyor unit 2 with respect to the drive unit 3.

The tip of the latching tongue 11 can have a suitable colored marking which is visible from the outside in the latched connection position and is designed as a connection indicator 36 . In particular, a marking can be arranged in an area between the insertion bevel 11.2 and the latching area 11.1. It can thus be recognized in a simple manner whether the snap hook connection 60 has been produced correctly. If the latching tongues 11 are not fully latched into the recesses 12, an edge of the recess 12 covers the colored marking, as a result of which the assembly personnel can identify an assembly error.

The depictions in the Figures 21 to 23 show different pump arrangements 100, which are described below.

The pump assemblies 100 each have a delivery unit 2 , a drive unit 3 connected thereto and one or more valve units 18 .

The delivery unit 2 has at least two connecting elements 27 , 28 for the detachable connection of the delivery unit 2 to a valve unit 18 . The connecting elements 27, 28 can be arranged directly on the delivery unit 2 or indirectly via an adapter-like intermediate element 37. In the exemplary embodiment shown, the connecting elements 27, 28 are designed as bayonet hooks and corresponding recesses and are arranged on the side of the delivery unit 2, so that the valve unit 18 can be connected to the drive unit 3 in a direction transverse to the drive unit 3 by means of a bayonet connection 70 . The housing of the drive unit 3 and the valve housing of the valve units 18 can move in the same direction (cf. 21 ) or in the opposite direction (cf. 22 ), or perpendicular to each other (cf. 23 ) extend.

Alternatively, the connecting elements for connecting the delivery unit 2 to the valve unit 18 can also be designed as latching tongues and corresponding recesses for producing a snap hook connection.

The bayonet connection 70 and the snap hook connection can be designed in accordance with the latching connections between the conveyor unit 2 and the drive unit 3 described above.

The valve units 18 can also be connected to one another by means of corresponding connecting elements 29, 30, cf. 23 . In this way, series arrangements of valves can be produced to carry out various switching operations. Alternatively, the valve units 18 can be connected to one another via intermediate elements 37 . The Connecting elements 29, 30 of the valve units 18 are designed as latching elements and can be designed in particular as bayonet hooks and corresponding recesses or as latching tongues and corresponding recesses.

The connecting elements 27, 28, 29, 30 are preferably designed to correspond to the connecting elements 7, 8, 11, 12 of the conveyor unit 2 or the drive unit 3.

A method for the tool-free, detachable connection of the conveyor unit 2 and the drive unit 3 is described below.

First, a method for connecting the conveyor unit 2 and the drive unit 3 via a bayonet connection 50 according to the first embodiment will be described.

For connection, the drive unit 3 is moved axially aligned in the insertion direction R along the drive axis A toward the delivery unit 2 , with the intermediate shaft 14 engaging in a corresponding round bore of the fastening region B. Furthermore, the bayonet hooks 7 engage in the plug-in areas 8.1 of the respective recesses 8, cf. 9c . As soon as the intermediate element 6 and the conveyor unit 2 lie flat against one another, the drive unit 3 and thus the intermediate element 6 are rotated clockwise relative to the conveyor unit 2 . The latching parts 7.2 of the bayonet hooks 7 latch with the securing areas 8.2 of the respective recesses. Furthermore, when the connection position is reached, the safety lug 10.2 of a reverse rotation safety device 10 snaps into a corresponding safety recess 10.3 of the intermediate element 6, cf. Fig. 9e . In addition, tolerances are compensated for when the conveyor unit 2 and the drive unit 3 rotate relative to one another by the compensation ramps 9, which can deform to compensate for tolerances, cf. Figure 12b .

When connecting the delivery unit 2 to the drive unit 3, the actuating contour 14.1 of the intermediate shaft 14 engages with the corresponding actuating contour 16.1 of the driven gear wheel 4.1.

Such a bayonet connection 50 between delivery unit 2 and drive unit 3 is released using the same steps described above in reverse order. Furthermore, the turning and plugging directions are reversed accordingly.

A method for connecting the conveyor unit 2 and the drive unit 3 via a snap hook connection 60 according to the second embodiment is described below.

For connection, the drive unit 3 is moved in the plug-in direction R along the drive axis A towards the conveyor unit 2 , with the intermediate shaft 14 engaging in a corresponding round bore of the fastening area B. Furthermore, the locking tongues 12 engage with their tips in the recesses 11, cf. 17 . With further insertion, the insertion bevels 11.2 of the latching tongues 11 come into contact with the edges of the recesses 12, as a result of which the latching tongues 11 deflect radially inwards with further axial displacement. When the connection position is reached, the latching tongues 11 spring out automatically and the latching area 11.2 of the latching tongues 11 latches with the latching area 12.1 of the respective recess 12, cf. 20 .

When connecting the delivery unit 2 to the drive unit 3, the actuating contour 14.1 of the intermediate shaft 14 engages with the corresponding actuating contour 16.1 of the driven gear.

Such a snap hook connection 60 between conveyor unit 2 and drive unit 3 is released by applying a release force counter to the plug-in direction R. As a result, the latching areas 11.2 of the latching tongues 11 can disengage from the latching areas 12.1 of the recesses 12 and the connection can be released.

As described above, the gear pump 1 and the pump arrangement 100 are characterized by a simple and error-free connection of the drive unit 3 to the delivery unit 2, which can also be carried out safely by inexperienced assembly personnel.

Another significant advantage of the gear pump 1 and the pump arrangement 100 lies in the improved hygiene properties both in the conveying and in the rinsing operation. This is explained in detail below.

The depictions in the Figures 24a and b show further views of the gear pump 1 for pumping a fluid stream F, from which it becomes clear how the fluid stream F flows through the gear pump 1 in the pumping and flushing modes.

As previously explained, a gear space 35 is arranged in the delivery unit 2, which has an inlet 31 and an outlet 32 for the fluid. The inlet 31 and the outlet 32 can be flow-connected outside of the gear space 35 via connections 26 to various components of the fluid circuit or the conveying system and can be arranged as desired. In the exemplary embodiment shown, the connection 26 connected to the inlet 31 is guided, for example, through the cover 2.2 of the delivery unit 2, cf. 26 .

The conveying operation represents the essential operating mode of the gear pump 1, in which, for example, drinking water, milk or coffee is conveyed in a drinks machine for the provision or preparation of drinks. In pumping operation, the fluid in the direction of flow S ₁ conveyed from the inlet 31 to the outlet 32, cf. 24a . The fluid enters the gear wheel space 35 through the inlet 31 and flows into a plurality of pocket-like spaces delimited by the teeth of the gear wheels 4.1, 4.2 and the wall of the gear wheel space 35. By rotating the gears 4.1 and 4.2 in opposite directions, the fluid is mainly conveyed along the outer wall of the gear space 35 to the outlet 32. According to the arrow representation in 24a the driven gear wheel 4.1 rotates clockwise during conveying operation and the co-rotating gear wheel 4.2 correspondingly counterclockwise. A pressure difference between the inlet 31 and the outlet 32 is generated in the gear chamber 35 by the rotation of the gear wheels 4.1, 4.2. During pumping operation, there is a negative pressure in the area of the inlet 31 and an overpressure in the area of the outlet 32, with the actual pressure conditions depending on a wide variety of parameters, such as in particular the operating point of the gear pump 1, the properties of the fluid and the exact point under consideration in the gear space 35 .

In a rinsing operation, which serves to rinse or clean the components and parts through which the fluid flows, the direction of flow S ₂ of the fluid is reversed, cf. Figure 24b . In this operating mode, the fluid flows from the outlet 32 to the inlet 31. The direction of rotation of the gear wheels 4.1, 4.2 is reversed for this purpose. The driven gear wheel 4.1 rotates during flushing operation as shown in Figure 24b counterclockwise and the co-rotating gear 4.2 accordingly clockwise. In the conveying mode, there is a negative pressure in the area of the outlet 32 and an overpressure in the area of the inlet 31 .

The driven gear 4.1 is operatively connected to an intermediate shaft 14 for driving and for generating the rotational movement of the gears 4.1, 4.2. The intermediate shaft 14 extends from the drive unit 3 into the gear wheel space 35 of the conveyor unit 2. This is a media separation of the dry area on the drive side from the area of the gear pump 1 through which fluid flows, on the delivery or gear wheel side, is required, which is explained below with reference to the illustrations in 25 and 26 is explained.

The drive unit 3 is located in the dry area of the gear pump 1 through which fluid does not flow. The drive unit 3 has the intermediate element 6 which is fastened to the end face and has the shaft bearing 13 for supporting the intermediate shaft 14 . The intermediate element 6 is accommodated in a drive space 103 of the housing 2 . 1 of the delivery unit 2 . The drive space 103 is located in the dry area of the conveyor unit 2.

In the housing 2.1, a side chamber 101 adjoins the drive chamber 103 in the axial direction along the axis of rotation D. Viewed in the axial direction of the axis of rotation D, the secondary chamber 101 is located between the drive chamber 103 and the gear chamber 35. In the secondary chamber 101, the shaft sealing ring 15 is arranged, which in the present exemplary embodiment is designed as a radial shaft sealing ring. The shaft sealing ring 15 encloses the intermediate shaft 14 in a fluid-tight manner along its circumference. In this way, the media are separated in the secondary space 101 between the drive-side, dry area and the gear-side, fluid-flowing area of the gear pump 1. According to the illustration in 25 the dry area is thus located along the axis of rotation D to the left of the shaft sealing ring 15 and the area through which fluid flows to the right of it.

The bushing 114 with the previously described slide bearing 17 for supporting the intermediate shaft 14 adjoins the secondary space 101 along the axis of rotation D in the direction of the gearwheel space 35 . Arranged along the axis of rotation D behind the slide bearing 17 is the gear space 35, in which the intermediate shaft 14 engages with the actuating contour 14.1 in the actuating contour 16.1 of the driven gear 14.1. A turning movement of the Intermediate shaft 14 is transmitted to the driven gear wheel 4.1 via the actuating contours 14.1, 16.1.

As is already clear from the above explanations, the secondary space 101 and the gear space 35 are flow-connected. The fluid can flow from the gear space 35 through an annular gap 105 formed in the area of the passage 114 into the secondary space 101 . The annular gap 105 results from the design, since a certain amount of play is provided in the area of the passage 114 or of the plain bearing 17 designed as a hydrodynamic plain bearing and the intermediate shaft 14 .

Since the secondary chamber 101 is flow-connected to the gear chamber 35 via the annular gap 105, fluid flows from the gear chamber 35 through the annular gap 105 into the secondary chamber 101 during operation of the gear pump 1. This fluid can collect and back up in the secondary chamber 101.

Such a stagnation and accumulation of fluid is to be avoided in particular for applications with high hygienic requirements, such as exist when pumping drinking water or other liquids from the foodstuffs sector. For this reason, the gear pump 1 has a further flow connection between the gear chamber 1 and the secondary chamber 101, which is explained below based on the illustration in 26 is explained.

The additional flow connection between the gear space 35 and the side space 101 is designed as a bore-like outflow opening 104, to a certain extent as ventilation. The outflow opening 104 extends from a region of the gear space 35 below the driven gear 4.1 essentially parallel to the axis of rotation D of the intermediate shaft 14 into the auxiliary space 101. The cross-sectional area of the outflow opening 104 is larger than the cross-sectional area of the annular gap 105. In this way ensures that a larger volume of fluid can flow through the outflow opening 104 than through the annular gap 105.

The outflow opening 104 is arranged in a region of the gear wheel space 35 in which there is a negative pressure during delivery operation. In the embodiment according to 26 the outflow opening 104 is formed in the vicinity of the inlet 31 . The arrangement in the negative pressure area of the gear space 35 enables fluid to flow from the secondary space 101 into the gear space 35 and not be conveyed or pressed in the opposite direction from the gear space 35 through the outflow opening 104 into the secondary space 35 . In this way, a flow from the secondary space 101 through the outflow opening 104 into the gear space 35 can be achieved during delivery operation. In addition, the outflow opening 104 is arranged and designed in such a way that when the gear pump 1 is at a standstill, ie when the gears 4.1, 4.2 are not rotating, it allows fluid to drip out of the secondary space 101 into the gear space 35 due to the influence of gravity. In this way, accumulations and congestion of fluid in the adjacent space 101 are avoided.

Based on the above explanations, it is clear that in conveying operation a flow path runs through the annular gap 105, the secondary space 101 and the outflow opening 104 in addition to the main flow. This flow path corresponds to a secondary flow path, with the main flow path running in flow direction S ₁ in gear space 35 from inlet 31 to outlet 32 . The portion of the fluid flow F that flows along the main flow path is referred to below as the main flow portion H, and the portion of the fluid flow F that flows along the secondary flow path is referred to as the secondary flow portion N.

The secondary flow portion N flows partially through the gear space 35, in particular between the inlet 31 and the annular gap 105 and between the outflow opening 104 and the outlet 32. The secondary flow portion N of the total fluid flow F is influenced by various parameters. It depends, for example, on the operating point of the gear pump 1, the achievable pressures, the viscosity of the fluid and the dimensions of the outflow opening 104 and the annular gap 105. As a rule, however, the proportion of secondary flow N is less than 20%, in particular less than 5% and in a preferred embodiment less than 1% of the total fluid flow F. In pumping operation, a larger proportion of secondary flow N ensures better flushing of the secondary chamber 101. A smaller proportion of secondary flow N On the other hand, ensures efficient operation of the gear pump 1, which is why the secondary flow component N is generally kept as low as possible in delivery operation.

The situation is different in the rinsing operation, in which it is not a performance-efficient delivery of the rinsing fluid that is desired, but good rinsing of the adjacent space 101 as well. For this reason, means 102 are provided for increasing the secondary flow proportion N in the flushing operation, the function of which will be discussed in more detail below. First of all, however, it should be explained again what the situation would be like without the corresponding funds 102:
In flushing operation, the fluid flows along the direction of flow S ₂ in the gear space 35 from the outlet 32 to the inlet 31, cf. Figure 24b . Correspondingly, there is now generally an overpressure in the gear space 35 in the vicinity of the inlet 31, where the outflow opening 104 is arranged, in contrast to the conveying operation. In this way, fluid is pushed into the secondary space 101 through the outflow opening 104 . Since the annular gap 105 as a further flow connection to the gear space 35 has a smaller cross-sectional area than the outflow opening 104, only a small amount of fluid can flow back into the gear space 35 via it. Without the means 102, the result would be an accumulation and accumulation of fluid in the adjacent space 101 and poorer rinsing of the side chamber 101. The fluid that has accumulated in the side chamber 101 could flow back through the outflow opening 104 back into the gear wheel chamber 35 only when switching over from rinsing to conveying operation. In order to prevent this, the gear pump 1 has means 102 for increasing the secondary flow component N in the flushing mode.

The basic idea behind the use of the means 102 is the setting of a low secondary flow component N in pumping operation, as a result of which a good pumping capacity and efficiency of the gear pump 1 can be achieved. In the rinsing mode, on the other hand, the means 102 are intended to increase the proportion of secondary flow N in order to achieve better rinsing of the secondary space 101 .

In the following, based in particular on the representation in 26 an exemplary embodiment of such means 102 is explained.

According to the illustration in 26 the means 102 are formed by a flushing channel 106 extending between the gear wheel space 25 and the auxiliary space 101 . This scavenging channel 106 forms an additional flow connection between the gear wheel space 35 and the side space 101, through which flow can only take place during the scavenging operation, but not during the conveying operation.

In the present exemplary embodiment, the scavenging channel 106 is arranged below the driven gear wheel 4.1 in a region of the gear wheel space 35 in which there is generally an overpressure during conveying operation and, correspondingly, a negative pressure in the scavenging operation. Due to this negative pressure in the flushing operation, the fluid that is backed up in the secondary chamber 101 flows through the flushing channel 106 into the gear chamber 35. The secondary flow path in the flushing operation thus runs via the outflow opening 104 and, if necessary, the annular gap 105 in the area of the passage 114 into the secondary chamber 101 and through the flushing channel 106 back into the gear space 35. A gathering and accumulation of flushing fluid in the secondary space 101 is avoided and the secondary space 101 is thoroughly flushed. Furthermore, there is no risk that flushing fluid provided with cleaning agent will flow back into the gear wheel space 35 and contaminate the fluid during delivery operation. Since the flow cross section of the scavenging duct 106 is larger than that of the outflow opening 104 and in the present exemplary embodiment even larger than the sum of the flow cross sections of the outflow opening 104 and the annular gap 105, more fluid can flow through the scavenging duct 106 from the side chamber 101 into the gear wheel space 35 than in flows into the side room 101. In summary, the scavenging channel 106 allows an increase in the bypass flow portion N in scavenging operation.

However, the proportion of secondary flow N in the overall fluid flow F is also lower in flushing mode than the proportion of main flow H. However, the proportion of secondary flow N is increased compared to pumping operation in order to enable thorough flushing of secondary space 101 .

In pumping operation, the increased secondary flow component N is often not desired, since there is less need to flush the secondary chamber 101 and the increased secondary flow component N can negatively influence the delivery capacity of the gear pump 1 . In order to be able to prevent fluid from flowing through the scavenging channel 106 into the secondary chamber 101 in the same way as in the scavenging mode, the means 102 therefore also have a closing device 107 for closing the scavenging channel 106 .

The design of the locking device 107 is described below with reference to the illustrations in 26 and 27 explained.

The closing device 107 is designed and arranged in such a way that flow through the scavenging channel 106 is only possible during scavenging operation. In this way it can be achieved that the increased secondary flow component N only is present in the flushing operation and the conveying operation is not impaired. The closing device 108 is arranged at the end of the scavenging channel 106 on the gearwheel side, but can alternatively also be arranged at the end on the adjacent room side or in other sections of the scavenging channel 106 .

The closing device 107 has a closing element 108 which is movably mounted and is designed in such a way that it can automatically close and open the scavenging channel 106 . Closing and opening can take place under the influence of the pressure of the flowing fluid. In the embodiment according to 26 and 27 the closing element 108 is designed as a ball. The closing element 108 is designed in such a way that it closes the scavenging channel 106 during pumping operation, cf. 27 . The closing element 108 is pressed onto a closing surface 111 by the overpressure prevailing in the gear space 35 in the region of the scavenging channel 106, see also FIG Figure 28b , and prevents the flow through the scavenging channel 106 from the gear space 35.

In the conveying mode, on the other hand, the closing element 108 is automatically lifted off the closing surface 111 and opens the scavenging channel 106, cf Figure 29b . The lifting of the closing element 108 from the closing surface 111 takes place due to the changed pressure conditions in the flushing operation. Because in contrast to the pumping operation, there is now a negative pressure in the gear space 35 in the area of the scavenging channel 106 . In addition, the secondary chamber 101 is fed through the outflow opening 104 and the annular gap 105 with rinsing fluid, which flows out of the rinsing channel 106 into the gear chamber 35 and in the process lifts the closing element 108 . In the open position of the closing device 107, the closing element 108 rests against an end face of the toothed wheel 4.1, cf. 26 and 27 . This achieves a captive configuration. Furthermore, the scavenging channel has a guide 112 for guiding the opening and closing movements of the closing element 108 . The guide 112 has for this purpose guide surfaces, which support the closing element 108 and prevent it from tilting or jamming, cf Figure 31b .

The closing device 107 is designed as a check valve for opening and closing the scavenging channel 106 .

In the following, the functioning of the means 102 for increasing the secondary flow proportion N in the scavenging operation is explained using the illustrations in FIGS Figures 28a and b and 29a and b explained. In the Figures 28a and b the production operation is shown and in Figures 29a and b the rinsing operation. In each case, the fluid flow F and its division into main flow portions H and secondary flow portions N are shown in a highly simplified schematic. Since the flow directions S ₁ , S ₂ of the fluid are locally strongly dependent on various parameters, such as the operating point of the gear pump 1, the properties of the fluid and also the section plane under consideration, only exemplary, simplifying information on the fluid flow F is given below in order to To explain the principle of increasing the bypass flow fraction N in the flushing operation. In real operation of the gear pump 1, the flow directions S ₁ , S ₂ and flow paths can deviate depending on the different influencing factors.

The representation in 28a illustrates an example conveying operation. The driven gear 4.1, which for reasons of clarity in 28a is not shown, is driven in rotation via the intermediate shaft 14 in the clockwise direction. The fluid stream F therefore flows as shown in 28a essentially along the direction of flow S ₁ from left to right, from the inlet 31 (not shown) to the outlet 32 (also not shown), see also 24a . In the overpressure area of the gear chamber 35 near the outlet, a certain proportion of the fluid flows through the annular gap 105 into the secondary chamber 101. The fluid cannot flow through the flushing channel 106 because the closing device 107 is closed. ie the closing element 108 rests against the closing surface 111 and closes the scavenging channel 106. The secondary flow component N flows back through the outflow opening 104 into the gear wheel chamber 35 and combines with the fluid flow F.

In the flushing mode, in which the direction of rotation of the gear wheels 4.1, 4.2 is reversed, cf. Figure 29a , the fluid flow F flows in the opposite direction from the outlet 32 to the inlet 31, cf. Figure 24b . Analogously to the conveying operation, fluid flows in the overpressure area of the gear space 35 through the annular gap 105 into the secondary space 101. In this case, a certain proportion of the fluid flow F also flows through the outflow opening 104, since this is in the overpressure area of the gear space 35 in the flushing operation of the present exemplary embodiment. These two partial streams combine in the side room 101 and flow back through the open scavenging channel 106 from the side room 101 into the gear wheel room 35 . The closing element 108 is at a distance from the closing surface 111, lies on the front side of the gear wheel 4.1 and opens the scavenging channel 106.

The comparison of the greatly simplified, schematic representations of the flow components in the Figures 28b and 29b shows that the secondary flow component N flowing through the secondary chamber 101 in the scavenging operation according to FIG Figure 29b to the funding company Figure 28b is increased.

In the following, based on the illustrations in the Figures 30a to 31b Structural details of the outflow opening 104 and the means 102 for increasing the secondary flow proportion N are explained.

As shown in the illustration Figure 30a can be seen, the outflow opening 104 is arranged in a wall of the gear space 35 . The outflow opening 104 is arranged as a round bore in the vicinity of the inlet 31, where there is usually a negative pressure during pumping operation. Since the outflow opening 104 is arranged below the driven gear wheel 4.1, the outflow opening 104 can be closed by a tooth of the gear wheel 4.1 when the gear wheels 4.1, 4.2 are stationary. Since in this case there would no longer be a flow connection to the secondary chamber 101 and in particular no fluid could flow back from the secondary chamber 101 into the gearwheel chamber 35, the outflow opening 104 has a channel-like orifice 113 whose length is greater than the width of a tooth. Thus, regardless of the position of the gear wheel 4.1, there is always a flow connection between the gear wheel space 35 and the secondary space 101 via the outflow opening 104.

The representations in Figures 31a and b show that the flushing channel 106 is also located below the driven gear 4.1, but in the vicinity of the outlet 32. In this area, there is a negative pressure during flushing operation, so that the closing element 108 is automatically lifted off the closing surface 111 and the flushing channel 106 opens. Figure 31b shows the guide 112 for the closing element 108. In addition, the scavenging channel 106 has two channel-like orifice openings 110 at its gear-side end. These orifices 110 are flow-connected to a compensation chamber 109 .

Below is the function and structural design of the compensation space 109 based on Figure 31b explained.

In the present exemplary embodiment, the gear pump 1 has two compensation chambers 109 which are designed as elongated, channel-like recesses in the wall of the gear chamber 35 . The compensation chambers 109 serve as so-called squeeze grooves or squeeze volumes and are arranged in the area of the gearwheel space 35 in which the teeth of the gearwheels 4.1 and 4.2 are in mutual engagement. In operation of the gear pump 1, both in the delivery and in the flushing operation, a certain proportion of the fluid squeezed between the teeth of the gears 4.1, 4.2. This can suddenly result in high pressure peaks in the fluid, which act on the gears 4.1, 4.2 and their bearings. In order to compensate for these pressure peaks or bring about a pressure equalization, the compensation chambers 109 are provided, into which the fluid can flow when it is squeezed between the teeth. The shape and position of the compensation spaces 109 can be adapted in particular to the size of the squeezed volume of the fluid.

Like this in Figures 31a and b As can be seen, one of the compensation chambers 109 is flow-connected to the end of the scavenging channel 106 on the gear wheel side. As a result, the fluid can flow back and forth between the flushing channel 106 and the compensation space 109 .

The representation in 32 illustrates the position of the inlet 31 and outlet 32, the outflow opening 104, the scavenging channel 106 and the compensation chambers 109 relative to the gears 4.1, 4.2. The outflow opening 104 and the scavenging channel 106 run essentially parallel to the axis of rotation D of the intermediate shaft 14 , which enables simple demolding during the primary molding production of the housing of the delivery unit 2 and in particular of the gear wheel space 35 .

Finally, a method for conveying a fluid flow F with a gear pump 1 is described, in which the secondary flow component N is increased in the flushing mode.

During delivery operation of the gear pump 1, the fluid in the gear chamber 35 flows from an inlet 31 to an outlet 32. A secondary flow component N of the fluid flow F flows back through the annular gap 105 into the secondary chamber 101 and through the outflow opening 104 into the gear chamber 35. The flushing channel 106 is closed by the closing element 108 .

When switching from delivery operation to flushing operation, the direction of rotation of the gears 4.1, 4.2 is reversed, the fluid stream F flows from the outlet 32 to the inlet 31 and the pressure conditions within the gear space 35 change. The bypass flow portion N of the fluid flow F is increased in that the closing element 108 opens the scavenging channel 106 . The secondary flow therefore flows back through the outflow opening 104 and the annular gap 105 into the secondary space 101 and through the scavenging channel 106 into the gear space. The reason why the proportion of secondary flow N is increased in scavenging operation compared to delivery operation is, among other things, because scavenging channel 106 has a larger cross-sectional area than outflow opening 104. Increasing the proportion of secondary flow N in scavenging operation improves the scavenging of secondary chamber 101.

The gear pump 1 described above, the pump arrangement 100 and the method for conveying a fluid flow F with such a gear pump 1 are therefore also characterized by improved hygienic properties both in the conveying and in the flushing mode.

References:

1

gear pump

2

conveyor unit

2.1

Housing

2.2

Lid

2.3

Wall

3

drive unit

3.1

Connection

3.2

drive shaft

4.1

gear

4.2

gear

5

connection area

6

intermediate element

7

fastener; bayonet hook

7.1

base

7.2

locking part

8th

fastener; recess

8.1

mating area

8.2

security area

9

balancing ramp

10

anti-reverse device

10.1

safety hook

10.2

safety nose

10.3

securing recess

11

fastener; locking tongue

11.1

rest area

11.2

lead-in bevel

12

fastener; recess

12.1

rest area

13

shaft bearing

14

intermediate shaft

14.1

actuating contour

14.2

shaft connection

15

shaft seal

16.1

actuating contour

16.2

bearing contour

17

bearings

18

valve unit

19

guide element

20

guide element

21

axis

22

fasteners; connector element

23

fasteners

24

mounting hole

25

poetry

26

Connection

27

fastener; bayonet hook

28

fastener; recess

29

fastener

30

fastener

31

enema

32

outlet

33

recess

34

annulus segment

35

gear room

36

connection indicator

37

intermediate element

50

bayonet connection

60

snap hook connection

70

bayonet connection

100

pump assembly

101

adjoining room

102

Middle

103

drive room

104

outflow opening

105

annular gap

106

flushing channel

107

locking device

108

closing element

109

compensation space

110

muzzle opening

111

closing surface

112

guide

113

muzzle opening

114

execution

A

drive axle

B

mounting area

D

axis of rotation

f

fluid flow

H

mainstream fraction

N

bypass fraction

R

mating direction

S1

flow direction

S2

flow direction

Claims (15)

Gear pump for delivering a fluid flow (F), the direction of flow (S ₁ , S ₂ ) of which can be reversed by switching between delivery and flushing operation, with two gears (4.1, 4.2) arranged in a gear space (35) and one with the gear space (35) flow-connected secondary chamber (101), the fluid flow (F) being formed by a main flow component (H) flowing through the gear chamber (35) and a secondary flow component (N) flowing at least partially through the secondary chamber (101),
marked by
Means (102) for increasing the proportion of secondary flow (N) in the flushing operation. Gear pump according to Claim 1, characterized in that the gears (4.1, 4.2) are operatively connected to a drive unit (3) via an intermediate shaft (14). Gear pump according to Claim 1 or 2, characterized in that components of the drive unit (3) are arranged in a drive chamber (103), the gear chamber (35) being arranged in an area through which fluid flows and the drive chamber (103) being arranged in a dry area, wherein a seal for the fluid-tight separation of the gear wheel space (35) from the drive space (103) is arranged in the secondary space (101). Gear pump according to Claim 2 or 3, characterized in that the intermediate shaft (14) is sealed off in the secondary space (101) via a shaft sealing ring (15). Gear pump according to one of the preceding claims, characterized in that a slide bearing (17) for supporting the intermediate shaft (14) is arranged between the gear wheel space (35) and the auxiliary space (101), the auxiliary flow portion (N) being at least partially controlled by a of the slide bearing (17) formed annular gap (105) flows. Gear pump according to one of the preceding claims, characterized by an outflow opening (104) which fluidly connects the gear space (35) to the auxiliary space (101). Gear pump according to Claim 6, characterized in that the secondary flow portion (N) flows along a secondary flow path during pumping operation, which leads through the annular gap (105), the secondary space (101) and the outflow opening (104). Gear pump according to one of the preceding claims, characterized in that the means (102) have a closable flushing channel (106) which extends between the gear wheel space (35) and the side space (101). Gear pump according to Claim 8, characterized in that the means (102) have a closing device (107) for closing the flushing channel (106), which is designed and arranged in such a way that flow through the flushing channel (106) is only possible in flushing mode. Gear pump according to Claim 9, characterized in that the closing device (107) has a movably mounted closing element (108) which is designed and arranged in such a way that the closing device (107) when switching between the conveying and the flushing operation automatically opens or closes the flushing channel (106). Gear pump according to Claim 10, characterized in that the closing element (108) in an open position of the closing device (107) on one of the gears (4.1, 4.2), in particular on an end face of one of the gears (4.1, 4.2), and/or in a Closed position on a closing surface (111) of the flushing channel (106). Gear pump according to one of the preceding claims, characterized in that the gear space (35) has at least one compensation space (109) for compensating for the squished volume of the gears (4.1, 4.2). Gear pump according to one of the preceding claims, characterized in that the secondary flow portion (N) flows in the flushing operation along a secondary flow path, which via the outflow opening (104) and the annular gap (105) into the secondary space (101) and out of the open flushing channel (106) leads into the gear space (35). Gear pump according to one of the preceding claims, characterized by a delivery unit (2) having the gears (4.1, 4.2) and a drive unit (3) driving the gears (4.1, 4.2) which, via connecting elements (7, 8, 11, 12 ) are detachably connected to one another, the connecting elements (7, 8, 11, 12) being designed as latching elements. Method for pumping a fluid stream (F) with a gear pump (1), wherein the direction of flow (S ₁ , S ₂ ) of the fluid stream (F) can be reversed by switching between a pumping and a flushing mode and wherein the fluid stream (F) is controlled by a through a gear space (35) flowing main flow component (H) and a secondary flow component (N) flowing at least partially through an auxiliary space (101),
characterized,
that the bypass flow proportion (N) is increased in the flushing mode.

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