EP3851674A1 - Double membrane pump - Google Patents

Abstract

Double diaphragm pump (1) with a mechanical drive mechanism with a pump housing (10) which has at least one suction connection (72) and at least one pressure connection (82) as well as a first diaphragm chamber (40) and a second diaphragm chamber (50), wherein in the first diaphragm chamber (40) a first membrane (42) separates a first delivery space (46) from a drive space (48) and in the second membrane chamber (50) a second membrane (52) separates a second delivery space (56) from an air chamber (58), wherein the first and second delivery spaces (46; 56) are connected to the at least one suction connection (72) on the one hand and the at least one pressure connection (82) on the other hand via valve devices (90; 92). The first membrane (42) and the second membrane (52) can be connected to a coupling rod (68) and at least one of the membranes (42; 52) can be moved by means of the mechanical drive mechanism. The mechanical drive mechanism of the double diaphragm pump (1) comprises a drive piston (120) and a ball joint (112) that can be accommodated therein as well as a receptacle (100) t which can be connected to the ball joint (112) and which is designed to be connected to an output shaft (20 ) to be coupled to a drive unit.

Description

Technical field of the invention

The present invention relates to a double diaphragm pump with a mechanical drive mechanism.

State of the art

Diaphragm pumps are used to convey fluids, especially liquids and gases. In general, a diaphragm pump has a diaphragm which is arranged in a diaphragm chamber and which separates a delivery space or fluid space or product chamber from a drive space, i.e. from a drive mechanism of the pump. Accordingly, the drive elements located in the drive space are not in contact with the at least partially aggressive fluid to be conveyed. The diaphragm is set in motion by a hydraulic, pneumatic, mechanical or electromagnetic drive mechanism. A mechanical diaphragm pump is generally more efficient, has a lower pulsation and can be used universally than, for example, a pneumatic diaphragm pump. Mechanical diaphragm pumps can be driven by an electric motor via an eccentric and a reciprocating piston or connecting rod.

Double diaphragm pumps comprise a pump housing with two parallel line sections which form a first diaphragm chamber and a second diaphragm chamber. In each of the membrane chambers, a membrane is arranged which sealingly separates the respective fluid space from the drive space. The drive mechanism of the double diaphragm pump is set up to move the diaphragms periodically. According to one type of membrane, the membranes can be coupled to a connecting shaft, also referred to as a coupling rod, and move in unison. Independent drive means of the membranes, which can be synchronized by means of a control, are also known.

By moving the membranes, the volumes of the conveying or fluid chamber and the drive chamber change complementarily to one another, so that the fluid chamber is filled with the medium to be conveyed in a suction movement and the fluid chamber is emptied in a pressure movement. The conveying direction is specified by means of arranged valve devices, so that an outlet side is blocked during the suction movement and an inlet side is blocked during a pressure movement. Double diaphragm pumps suck in fluid and push fluid out at the same time.

Diaphragm pumps with a multi-part pump housing are known, the individual housing parts of the pump housing being essentially plate-shaped, arranged along a longitudinal axis, sealed against one another and braced, for example, by means of fastening means. The housing parts are made of metal, for example, so that sealing forces to be applied axially can be applied without distortion and without settling. With certain designs of modular diaphragm pumps or double diaphragm pumps, the suction connection and pressure connection can be arranged in a suitable orientation depending on the requirements. Such diaphragm pumps are expensive to manufacture and can lose their strength or tightness over their lifetime under unfavorable operating conditions.

In general, double diaphragm pumps with diaphragms moved back and forth in unison, i.e. synchronously with one another, in order to alternately fill and evacuate the pumping chamber, have the disadvantage that there are periodically recurring pumping pressure drops on the outlet side. This leads to more or less severe interruptions in delivery and vibrations, which make downstream damping necessary. Furthermore, due to the material properties of the membranes, the delivery pressure shows a sawtooth-shaped curve over time.

It is known to operate diaphragm pumps with compressed air, this requiring the use of expensive compressed air that is only available to a limited extent. Accordingly, a specially coordinated one is required Infrastructure to make compressed air available on site, so that mobile use of the diaphragm pump is problematic.

Electromechanically operated double diaphragm pumps are known, a piston rod being in operative connection with a crank pin which is arranged on a free end of an output shaft of a geared motor. In this way, a rotary movement originating from the drive motor is converted into the linear movement of the piston rod or the diaphragms connected to it, as is the case for example in DE 20109650 U1 is described.

In a diaphragm pump, the diaphragm is subject to mechanical deformation during a pump cycle, so that over the life of the diaphragm pump, wear and tear and mechanical defects in the diaphragm often lead to the failure of the pump. Known membranes are made of a material with a certain elasticity, e.g. elastomers such as NBR (acrylonitrile butadiene rubber). Also known are composite membranes in a sandwich construction with a layer of an elastomer and a further, e.g. extruded, layer, for example PTFE, which is characterized by chemical resistance to aggressive media and is therefore provided on the medium side.

Structural diaphragms are known so that the diaphragm is sufficiently dimensionally stable and sufficiently elastic to be deformed during pump operation by the opposing pressure forces acting on opposite diaphragm sides. These can, for example, have concentric webs or radial ribs on their side facing away from the fluid space, which allow a defined flexing movement of the structural membrane during the pumping operation. Molded and structured diaphragms can have a Teflon coating on their three-dimensional surface facing the medium.

Summary of the invention

The object of the present invention is to further develop a double diaphragm pump with a mechanical drive mechanism. The double diaphragm pump according to the invention can be manufactured inexpensively and has a compact design. The double diaphragm pump can be dismantled and parts subject to wear and tear are easy to replace, with no need for sealants on the product or medium side. Furthermore, the double diaphragm pump according to the invention is also suitable for pumping aggressive chemicals and fluids with a solid content. In addition, the double diaphragm pump is characterized by a high degree of efficiency and almost vibration-free operation, so that the good stability allows universal use.

The objects are achieved according to the invention with a double diaphragm pump with the features of claim 1. Advantageous configurations of the double diaphragm pump result from the features of the independent patent claims.

Although the invention relates to a double diaphragm pump, other diaphragm pumps with a mechanical drive mechanism are also included in principle.

The double diaphragm pump according to the invention with a mechanical drive mechanism comprises a pump housing which has at least one suction connection and at least one pressure connection as well as a first diaphragm chamber and a second diaphragm chamber. In this case, a first membrane in the first membrane chamber separates a first delivery space from a drive space and in the second membrane chamber a second membrane separates a second delivery space from an air chamber. In the event that both membranes can be moved by a mechanical drive mechanism, the second membrane chamber is designed as a mirror image of the first membrane chamber. The delivery spaces are connected to at least one suction connection on the one hand and the pressure connection on the other hand via valve devices. Furthermore, the first membrane and the second membrane can be connected to a coupling rod. By the mechanical Coupling is a transmission of the movement of one of the membranes, generated by the mechanical drive mechanism. A symmetrical design of the pump housing in relation to the suction and pressure connection is particularly advantageous, so that it can optionally be re-assembled for use in a reversed orientation.

The mechanical drive mechanism of the double diaphragm pump comprises a drive piston and a ball joint that can be accommodated therein as well as a receptacle which can be connected to the ball joint and which is designed to be coupled to an output shaft of a drive unit designed as an eccentric shaft.

Accordingly, a diaphragm chamber is formed in the pump housing in two parallel line sections, in which free-swinging diaphragms are arranged so that a product or fluid chamber, referred to as the pumping chamber, and a drive chamber or an air chamber are sealingly separated from one another. The drive space and air chamber of the two membrane chambers can be connected to one another by means of an air duct, preferably with a small diameter. Accordingly, when the diaphragms move in the other air chamber or the drive space, a counterpressure that builds up and decreases is generated. This counter pressure supports the movement of the diaphragms and serves to compensate for thermal effects and pump circulation effects.

The two membranes, also referred to as the first membrane and the second membrane, can be connected to one another by a rigid coupling rod which extends axially along a longitudinal axis through the center of each of the membranes and is releasably attached to the membranes. For this purpose, a fastening element is provided in a central zone on each of the membranes, for example vulcanized, which serves on the one hand for the detachable fastening of the coupling rod to the respective membrane and on the other hand for axially securing one of the membranes against or for releasable fastening with the drive piston of the mechanical drive mechanism. For this purpose, each fastening element can have an internal thread, in which external thread, formed at ends the coupling rod, or vice versa. Furthermore, an internal thread can be provided on a membrane for connection to the mechanical drive mechanism on the fastening element, into which an external thread of the drive piston is screwed or vice versa. Fastening by means of screwing has the advantage that the assembly is easy to handle, inexpensive and can be dismantled, and also enables adjustability in order to set a delivery volume. The fastening element is preferably designed in the form of a disk, the diameter being selected such that it largely covers a central zone of the membrane. In particular, the fastening element is made of metal, as a result of which a dimensionally stable and precise fastening is possible on the one hand for the coupling rod and on the other hand for the drive component of the drive mechanism.

By means of the coupling rod and the mechanical drive mechanism, the membranes are moved back and forth between two movement end points in push-pull. However, it is also conceivable that the membranes are moved by separate drive means, with the movement of the membranes being able to be coordinated by means of an included control. In the course of the movement, one of the conveying spaces is alternately filled with the medium or fluid to be conveyed in a suction movement and emptied in a pressure movement. Valve devices at the suction connection and at the pressure connection specify the conveying direction by blocking the outlet side during the suction movement and the inlet side of the respective membrane chamber during the pressure movement.

To move the membranes, a drive unit, for example a motor, is provided which can be coupled to the mechanical drive mechanism. The drive unit can be detachably connected to the pump housing, for example by means of a correspondingly designed flange connection. A free end of an output shaft of the drive unit protrudes into the pump housing and is provided there with an eccentric. For example, an output shaft designed as an eccentric shaft engages in the receptacle, the eccentric being able to be placed on a roller, ball or nail bearing and an outer ring of the bearing being able to be received in the receptacle. In In one embodiment, the receptacle comprises a threaded hole on a side surface and thus perpendicular to the axis of the output shaft, into which a component of the drive mechanism designed as a ball joint can be screwed and is held in a clamping position. The ball joint can be designed in such a way that it has a ball head and a threaded shaft extending therefrom, at the free end of which a threaded area is formed. The ball joint is designed to transmit the movement emanating from the drive unit and the eccentric to one of the membranes.

In one embodiment, the threaded bore provided in the receptacle is slotted, with a width of the slot being able to be changed by means of screwing means. In a released state, the screw means enable the threaded shaft to be positioned in the threaded bore and thus the ball joint relative to one of the membranes and, in a tensioned state, fix the adjustable or set position.

The ball joint is received in the drive piston, which can be connected to one of the diaphragms and is received displaceably within the pump housing. A seal is in sealing contact with the drive piston and is received in a groove formed on the pump housing. Accordingly, no lubricants are required for the displaceable mounting of the drive piston, but an arrangement with dry lubrication is present.

The ball joint or the ball head is mounted in a bearing block that can be received in the drive piston, so that a rotary movement of the output shaft is transformed into a longitudinal movement of the drive piston and can be transmitted to one of the membranes. The bearing block itself can be constructed in several parts and can be positioned within the drive piston. For example, the bearing block can bear against inserts, for example cylindrical spacers, received in the drive piston. Alternatively, the end faces of the bearing block can be attached appropriately designed stops rest in the interior of the drive piston.

In one embodiment, the drive piston has a through-hole so that the ball joint can be dismantled from the receptacle in the stored position by means of an insertable tool. In this case, a tool holder can be formed on the ball head, in which a tool that can be introduced through the through hole engages and can be connected to the ball joint in a rotationally fixed manner. This through-hole enables the components of the mechanical drive mechanism to be dismantled.

The drive piston can be designed in several parts, with sleeve-shaped components being connectable to one another by a screw connection.

In a preferred embodiment, spring means can be received in the drive piston, between which the ball joint can be stored in a pretensioned manner. The position of the ball joint is accordingly pre-tensioned so that it can always be reset to an initial position. The reset takes place against a spring force of one of the spring means. By arranging the spring means within the drive piston, a compact structure with reduced installation space can be realized. The arrangement of the spring means allows a kind of overload protection which enables the ball joint and thus the drive piston to be automatically reset to an initial position.

The spring means (s) can be designed in the form of spiral springs or disc springs, a free spring length being adaptable to the stroke of the drive piston. Since a limited rotational movement of the ball joint around its longitudinal axis but no movement in the direction of the longitudinal axis is possible, the ball joint provides a power transmission with a stable, centered mounting that avoids tilting or rolling.

In one embodiment of the double diaphragm pump, the valve devices can be arranged in fluid-conducting connections of the delivery spaces on the one hand to the at least one suction connection and on the other hand to the at least one pressure connection. Accordingly, a passive valve device can be arranged on at least one suction opening provided in each delivery chamber, which valve devices open when the associated membrane is sucked. In one embodiment, the insertable valve device is designed as a plate valve made of an elastic plastic. The movable valve plate can be connected to a plug, which can be received on a connecting channel at the respective suction opening. Depending on the position of the plate valve, a fluid-conducting connection between the delivery chamber and the suction connection can be released or closed.

Furthermore, in the fluid-conducting connection of the delivery spaces with the pressure connection, the valve device that can be arranged there is designed as a flap valve made of an elastic plastic. In particular, the flap valve can be inserted in a crossing area between the connecting channels and an outlet channel, so that the flap valve alternately opens or closes one of the pressure openings of the delivery spaces of the first membrane chamber and the second membrane chamber. The flap valve is preferably designed in several parts. In one embodiment, the flap valve has a V-shape, a hinge shaft being held in a clamping manner at the base of the V-shape and being insertable into a hinge element. Accordingly, the flaps or wings of the flap valve can perform a tilting movement.

In one embodiment, the flap valve can be assembled and disassembled through the pressure connection. Here, at least the hinge element is firmly fixed in position and the hinge shaft, held in a clamping manner in the V-shape of the wing, can be pressed into receptacles on the hinge element.

In a further embodiment, the pump housing is constructed in several parts, with a pump cover, a control block, in which the suction connection for sucking in a fluid to be pumped and the Pressure connection are provided for the discharge of the pumped fluid and comprises a drive housing and can be connected to one another in a sealing manner.

The pump cover and control block therefore form a type of pump head which can be connected to the drive housing. The control block itself can be made in one piece or in several pieces. In one embodiment, the pump housing is made of a plastic which is in particular chemically inert and resistant to the medium to be conveyed. Alternatively, however, a design made of metal is also conceivable.

One of the diaphragm chambers, here referred to as the second diaphragm chamber, can be formed by the pump cover and the control block and the other of the diaphragm chambers, the first diaphragm chamber, is formed between the control block and the drive housing. On the parallel outer surface of the control block, circular depressions can be formed, each of which is arched over by one of the membranes. In particular, a circumferential groove is provided concentrically around the circular recess on each of the two outer sides of the control block, in which a peripheral annular bead of the respective membrane can be received. When assembling and connecting the multi-part pump housing, the membranes can be pressed together with their peripheral annular bead in a respective clamping area and held in the groove. The separating surfaces between the pump cover and the control block and between the control block and the drive housing are sealed against one another via the membrane that can be arranged in this separating surface. For example, the several parts of the pump housing can be connected to one another by means of screw connections which are provided in an arrangement which enables a uniform application of force.

In another embodiment, the control block can be constructed in several parts. In the case of the multi-part control block, the individual blocks can be connected to one another in a force-fitting and / or form-fitting sealing manner by pressing or another suitable connection technology.

The control block comprises a suction block with the suction connection and inlet channel and connection channels, a pressure block with the pressure connection and outlet channel and connection channels and a central block, designed to accommodate the coupling rod. In a suction area, the at least one suction connection is accordingly in fluid-conducting connection via an inlet channel and a respective connection channel with a suction opening of the respective delivery space of the first membrane chamber and the second membrane chamber. The fluid is conveyed from the conveying chamber via a pressure area via so-called pressure openings from the conveying chambers via respective connecting channels to an outlet channel and to the pressure connection. The direction of conveyance is determined by the position of the valve devices. The connecting channels can be T-shaped in the suction area and Y-shaped in the pressure area, for example.

The diaphragms that can be used are designed to be sufficiently dimensionally stable so that they are not deformed in a performance-reducing manner during pump operation by the opposing pressure forces acting on opposite diaphragm sides. In particular, each membrane is designed as a structural membrane. In a central zone of the membrane, a membrane core can be provided, which causes a certain stiffening of the central zone. The fastening element for connection to the drive mechanism and the coupling rod can also be used in this.

In addition to the central zone, the membrane can comprise one or more zones, each of which fulfills different functions. Thus, on the outer circumference, the membrane comprises the aforementioned annular bead and thus a clamping zone, by means of which the membrane is clamped between housing parts of the pump housing and is held in a sealing manner on the circumferential side. Centering and / or positioning in relation to the drive mechanism is possible by means of the clamping zone. Due to the sealing effect, the housing parts of the pump housing are sealed against the environment and against the drive mechanism in the area of the medium to be conveyed without additional sealing means.

One or more radial zones of the membrane can connect between the clamping zone and the central zone, which zones are convex and / or concave in the unloaded state of the membrane and, for example, fulfill a support function and / or a compensation function. This enables the diaphragm to be guided as safely and with as little vibration as possible. This also favors quiet operation.

Furthermore, the membranes on the side of the fluid or conveying chamber are made of a material which is largely insensitive to aggressive chemicals in particular. For example, the membrane can be made of a chemical-resistant, but at the same time very tear-resistant and elastic material, such as plastic. Each of the membranes preferably comprises at least two individual membrane layers lying on top of one another and connected to one another. In particular, these are plastic layers made of different materials, for example a PTFE (polytetrafluoroethylene) or a chemically modified PTFE with a certain glass fiber content, which show only a low tendency to deform under load and a low gas permeability. For the product side, plastics with high resistance, including against mineral oils and chemicals, as well as good technological properties such as swelling resistance, elasticity, and compression set resistance are suitable.

Due to the design of the mechanical drive mechanism and its connection to the diaphragms, the double diaphragm pump according to the invention can easily be dismantled into its individual parts. In addition, wearing parts, for example valve devices, can easily be exchanged if necessary without completely dismantling the double diaphragm pump. Using separate access options, membranes and valve devices can be exchanged separately from one another.

Brief description of the drawing

• Figur 1 eine perspektivische Ansicht eines Pumpengehäuses einer Doppelmembranpumpe mit einer darin angeordneten Abtriebswelle einer Antriebseinheit;
• Figur 2 einen Längsschnitt einer Doppelmembranpumpe in Seitenansicht mit einem Antriebsmechanismus gemäss einer ersten Ausführungsform;
• Figur 3 eine Detailansicht der Doppelmembranpumpe gemäss der ersten Ausführungsform in Draufsicht;
• Figur 4 eine teilweise geschnittene perspektivische Ansicht der Doppelmembranpumpe mit teilweise entfernten Ventileinrichtungen;
• Figur 5 eine teilweise geschnittene perspektivische Ansicht der Doppelmembranpumpe gemäss Figur 4 mit eingesetzten Ventileinrichtungen;
• Figur 6 eine perspektivische Detailansicht einer Ventileinrichtung, ausgebildet als Plattenventil;
• Figur 7 eine perspektivische Detailansicht einer Ventileinrichtung, ausgebildet als Klappenventil;
• Figur 8 eine perspektivische Ansicht eines Details des mechanischen Antriebsmechanismus;
• Figur 9 eine Detailansicht einer Doppelmembranpumpe mit einem mechanischen Antriebsmechanismus gemäss einer zweiten Ausführungsform.

Preferred embodiments of the invention are explained in more detail below with reference to the figures shown in the drawing. Show it:

• Figure 1 a perspective view of a pump housing of a double diaphragm pump with an output shaft of a drive unit arranged therein;
• Figure 2 a longitudinal section of a double diaphragm pump in side view with a drive mechanism according to a first embodiment;
• Figure 3 a detailed view of the double diaphragm pump according to the first embodiment in plan view;
• Figure 4 a partially sectioned perspective view of the double diaphragm pump with partially removed valve means;
• Figure 5 a partially cut perspective view of the double diaphragm pump according to Figure 4 with inserted valve devices;
• Figure 6 a perspective detailed view of a valve device, designed as a plate valve;
• Figure 7 a perspective detailed view of a valve device, designed as a flap valve;
• Figure 8 a perspective view of a detail of the mechanical drive mechanism;
• Figure 9 a detailed view of a double diaphragm pump with a mechanical drive mechanism according to a second embodiment.

Detailed description of the embodiments of the invention

Figure 1 shows a perspective view of a pump housing 10 of a double diaphragm pump 1. The pump housing 10 is constructed in several parts in the embodiment shown. It accordingly comprises a pump cover 12, a control block 14 and a drive housing 16. The drive housing 16 can be connected to a drive unit (not shown), for example an electric servomotor, or a conventional drive motor or air motor. An output shaft 20 of the drive unit designed as an eccentric shaft can be supported in the drive housing 16 and is in operative connection with a mechanical drive mechanism to be described below. The rotary movement of the output shaft 20 of the drive unit is thus transformed into a translational movement of the mechanical drive mechanism, ie into a sinusoidal movement. An opening 30, which marks an inlet or an outlet for the fluid to be conveyed, is shown schematically on one of the side surfaces of the pump housing 10. The pump housing 10 or parts thereof can be made from a plastic, for example from polytetrafluoroethylene or another chemically inert material.

Figure 2 shows a longitudinal section through the double diaphragm pump 1. The diaphragm pump shown as a double diaphragm pump 1 is not limited to an embodiment as a double diaphragm pump, but rather its technical principles can be applied to every conceivable embodiment of a diaphragm pump.

As indicated in Figure 2 the drive unit (not shown) can be detachably fastened to the pump housing 10 or the drive housing 16 by means of a flange connection. The output shaft 20 of the drive unit, designed as an eccentric shaft, protrudes into the interior of the drive housing 16 and is supported there. Furthermore, the eccentric formed on the output shaft 20 is in contact with a receptacle 100 or is received in a bearing arranged in the receptacle 100. The output shaft 20 can be coupled to the mechanical drive mechanism to be described in more detail, here on the Figures 3 , 9 and 10 is referred. The mechanical drive mechanism comprises drive components which are designed as a connecting rod or a push rod or drive rod and can be brought into operative connection with the output shaft 20. In particular, a drive piston 120 is provided which can be connected to a membrane in order to move it.

The illustrated double diaphragm pump 1 has a first diaphragm chamber 40 in the multi-part pump housing 10 between the drive housing 16 and the control block 14 and a second diaphragm chamber 50 between the control block 14 and the pump cover 12. In the first diaphragm chamber 40 and in the second diaphragm chamber 50, a membrane 42, 52 is arranged in a freely oscillating manner. The membranes 42, 52 each have a peripheral annular bead 44, 54, which is pressed together between the drive housing 16 and the control block 14 or between the latter and the pump cover 12 in a correspondingly designed clamping area and held there in a sealing manner. The membrane 42 separates a first delivery space 46 from a drive space 48 in the first membrane chamber 40 and the membrane 52 in the second membrane chamber 50 separates a second delivery space 56 from an air chamber 58 with changing volumes.

Like in the Figure 2 the drive space 48 and the air chamber 58 are shown connected to one another via an air duct 18, which is preferably designed with a small diameter. The air channel 18 is set up so that, when the membrane 42 in the first membrane chamber 40, for example, performs a suction movement, air is pressed from the drive space 48 into the air chamber 58 of the second membrane chamber 50. In the process, and due to the small diameter of the air duct 18, a pressure builds up in the diaphragm chamber 50, which supports the pressure movement of the second diaphragm 52 and vice versa.

The materials of the membranes 42, 52 are preferably elastomeric composites, for example NBR (acrylonitrile butadiene rubber), which takes on the function of an elastic base material in the composite. To conveying space 46; 56 towards and thus towards the conveyed medium can be attached to the membranes 42; 52 a chemically inert PTFE film (polytetrafluoroethylene) can be laminated on.

In each of the membranes 42; 52 is a fastener 60 in a central zone of the membranes 42; 52 recordable, e.g. embedded. The fastening element 60 may be formed with a shoulder that passes through one in the central zone of the membranes 42; 52 provided opening is performed. Furthermore, a disk-shaped area can be formed on the fastening element 60, which this opening or the central zone of the membranes 42; 52 covered and rests against this. The attachment of the fastening element 60 is designed as a component of a screw connection, ie has, for example, an internal thread 62 into which an external thread of either a cover element 64 or an external thread of a drive piston 120 comprised by the drive mechanism can be screwed. The latter is used to releasably connect one of the membranes 42; 52 with the drive mechanism.

Furthermore, on a side of the fastening element 60 opposite the shoulder, a second internal thread 66 is formed, into which an external thread of a coupling rod 68 for rigidly connecting the first membrane 42 and the second membrane 52 can be screwed. The arrangements of the threads can also be reversed. By means of the screw connections provided, the parts can be detached and dismantled from one another in a simple manner, so that an exchange of one of the membranes 42; 52 is easy to do. Other ways of connecting the membranes 42; 52 with the coupling rod 68 or the cover element 64 and / or drive piston 120 are conceivable. Thus, the coupling rod 68 with the membranes 42; 52 can be connected by means of a form fit, for example the coupling rod 68 can be connected to at least one of the membranes 42; 52 overmolded.

In the Figure 2 are the membranes 42; 52 in the form of a structural membrane, with several zones having different functions being able to be formed between the central zone and the annular bead 44. For this purpose are in the direction of conveying space 46; 56 concavely and / or convexly arched zones are conceivable, which can be designed as a support zone and / or as a compensation zone.

The membranes 42; 52 can have a membrane core 41 which, as a mold core, stabilizes the central zone in particular. The membrane core 41 can be made of metal, plastic or an elastomer in the membranes 42; 52 be vulcanized or glued in to prevent sagging the membrane 42; 52 above the suction or pressure openings to be described in the conveying spaces 46; 56 is reduced or canceled.

the Figure 3 shows a cross section of part of the double diaphragm pump 1 according to the embodiment of FIG Figure 2 in a top view. The same elements are denoted by the same reference symbols.

In the conveying spaces 46; 56 of the first membrane chamber 40 and the second membrane chamber 50 are at least one suction opening 70 and one pressure opening 80 each. A valve device designed as a plate valve 90, which determines the conveying direction of the fluid or medium to be conveyed, is accommodated at each suction opening 70. The fluid to be conveyed is fed via a suction connection 72 at the inlet, an inlet channel 74 and one of the connecting channels 76 to one of the suction openings 70 in the delivery chamber 46; 56 of the membrane chambers 40; 50 promoted, in which the arranged membrane 42; 52 is in the suction position. With a suction movement of the respective membranes 42; 52, the associated suction opening 70 is released by the corresponding plate valve 90. Details of the plate valve 90 are shown in Figure 7 shown.

The pumped fluid is when the membrane 42; 52, in which the corresponding plate valve 90, the suction opening 70 in the delivery chamber 46; 56 closes, conveyed via the pressure opening 80, the connection channel 76, an open flap valve 92 and an outlet channel 84 to a pressure connection 82. The flap valve 92 is arranged and designed at an intersection area between the connecting channels 76 and the outlet channel 84 that with the pressure movement of the membranes 42; 52 the fluid from one of the conveying spaces 46; 56 is squeezed out. Details of the flap valve 92 are shown in FIG Figure 8 shown. In particular, the flap valve 92 can be inserted or removed from the pump housing 10 via the outlet channel 84.

Out Figure 3 it can also be seen that a seal 122 is provided on an outer circumference of the drive piston 120, which seals the associated drive space 48.

the Figures 4 and 5 each show different phases of the assembly of a double diaphragm pump 1 according to an embodiment. In the Figures 4 and 5 the control block 14 is shown at least partially in section and shows its interior in each case. The respective connection channels 76 are visible, which provide a fluid-conducting connection on the one hand on the side of the suction connection 72 and on the other hand on the side of the pressure connection 82 for conveying fluid into or out of the first conveying chamber 46 of the first diaphragm chamber 40 and the second conveying chamber 56 of the second diaphragm chamber 50 enable. The conveying direction of the fluid to be conveyed or the conveyed fluid is determined by the movement of the membranes 42; 52 (not shown) predetermined position of the valve devices 90, 92. In the suction area in which the suction connection 72 is located, the plate valves 90 can be arranged at the respective suction openings 70. The plate valve 90 can be used in the connecting channel 76, which provides a corresponding recess.

During the suction movement of the associated membrane 42 or 52, the plate valve 90 opens the suction opening 70 and the fluid enters the enlarging delivery chamber 46; 56. Meanwhile, a fluid-conducting connection between the delivery chamber 46 or 56 to be filled and the pressure connection 82 is blocked by the flap valve 92 arranged there in the pressure area. In the event of a reversal of movement of the corresponding membrane 42; 52 in the pressure movement, the plate valve 90 closes the associated suction opening 70. The flap valve 92 moves into a position so that the fluid-conducting connection between the conveying chamber 46 to be emptied; 56 is released.

With reference to Figure 6 which shows a perspective view of a plate valve 90, the plate valve 90 comprises a plate 91a which is preferably made of an elastic material or plastic and is bent in a V-shape. On one side of the V-shaped plate 91a, a bore is provided in which a sleeve 91b is held, which can be inserted into the suction opening 70 or the connecting channel 76.

Out Figure 7 shows a perspective view of the flap valve 92. The flap valve 92 is designed in a V-shape and has two flap wings 93a, 93b. The material of the flap valve 92 is also an elastic plastic with very good mechanical properties, for example high mechanical strength, rigidity and wear resistance, which are suitable for continuous operation of the flap valve 92. PEEK (polyetheretherketone) is suitable, which is recommended for both thermally and mechanically highly stressed parts. At the base of the V-shape of the flap valve 92, a hinge shaft 94 is held and held, which protrudes with free ends over the wings 93a, 93b. The free ends of the hinge shaft 94 are in a hinge element 95 ( Figure 4 ) snap-in, and freely rotatable therein, so that the flap valve 92 can perform a tilting movement. The hinge element 95 is firmly received in a crossing area between the connecting channels 76 and the outlet channel 84, so that when the hinge shaft 94 is engaged, the flap wings 93a, 93b connected to it alternately one of the fluid-conducting connections to the conveying spaces 46; 56 opens or blocks.

In Figure 8 a detail of the mechanical drive mechanism is shown in perspective. Shown is the receptacle 100 in which the output shaft 20 of the drive unit (not shown) is rotatably mounted in a bearing 110 provided for this purpose, here designed as a ball bearing. The receptacle 100 forms a type of connecting rod with a ball joint 112, which is regarded as a component of the mechanical drive mechanism. The receptacle 100 corresponds in a certain way to a connecting rod head and largely has a cuboid shape. A slot 102 is formed on one of the side surfaces of the receptacle 100, which slot extends parallel to a base surface of the receptacle 100 and thus perpendicular to the output shaft 20. The slot 102 intersects a threaded hole 104 formed on the side surface. The width of the slot 102 is adjustable. For this purpose, screw means 106 are provided which change the width of the slot 102 depending on the position. The ball joint 112 comprises at one end a ball head 114, from which a threaded shaft 116 extends, at the end of which a threaded area is formed complementary to the threaded bore 104. In the embodiment shown, the ball joint 112 is formed in one piece, a multi-part design is also conceivable. Accordingly, the ball joint 112 can be screwed into the receptacle 100 and held in position by clamping, the width of the slot 102 being adjusted accordingly.

A tool holder 118 is formed on the ball head 114 in extension of the threaded shaft 116, in which a tool can be received in a rotationally secure manner. Accordingly, the ball joint 112 can be released from the receptacle 100 with the screw means 106 released. A simple adjustment of the tension of the diaphragm 42 which can be connected to the drive mechanism; 52 possible.

the Figure 9 shows a detailed view of the mechanical drive mechanism of the double diaphragm pump 1 in a sectional view. In this illustration, the ball joint 112 is connected to the receptacle 100 via the threaded shaft 116, ie it is screwed into the slotted threaded bore 104. The output shaft 20 designed as an eccentric shaft is received in the bearing 110.

The ball head 114 of the ball joint 112 is received in the drive piston 120. For this purpose, the ball head 114 is rotatably mounted in a multi-part bearing block 130, which is received in the drive piston 120 designed as a hollow piston, for example resting against one or more insertable spacers (not shown). In the embodiment shown, the drive piston 120 is constructed in several parts, the parts being connectable to one another by means of a screw connection 121. The drive piston 120 has a through hole 124 on one end face. A tool can be passed through the through bore 124 from the drive space 48 of the first diaphragm chamber 40 to the tool holder 118 on the ball head 114 in order to release the ball joint 112 from the holder 100.

Instead of or in addition to the spacers that can be received in the drive piston 120, spring means 140 can be arranged, which enable the multi-part bearing block 130 to be held in a pretensioned manner. In particular, the multi-part bearing block 130 is arranged between spring means 140 so that it can always be reset to its starting position. In this way, a type of overload protection is created which enables the mechanical drive mechanism and the first membrane 42 and second membrane 52 connected to it to be reset. Alternatively, the overload protection device can also be designed in the form of an electronic overload protection device. Reference number 1 Double diaphragm pump 92 Flap valve 10 Pump housing 93a, b Flap wing 12th Pump cover 94 Hinge shaft 14th Control block 95 Hinge element 16 Drive housing 18th Air duct 100 admission 20th Output shaft 102 slot 104 Threaded hole 30th opening 106 Screwing means 40 first membrane chamber 110 warehouse 50 second membrane chamber 112 Ball joint 114 Ball head 41 Membrane core 116 Threaded shaft 42 first membrane 118 Tool recording 44 Ring bulge 120 Drive piston 46 first funding room 121 Screw connection 48 Drive room 122 poetry 124 Through hole 52 second membrane 54 Ring bulge 130 Bearing block 56 second delivery room 58 Air chamber 140 Spring means 60 Fastener 62 inner thread 64 Cover element 66 second internal thread 68 Coupling rod 70 Suction opening 72 Suction connection 74 Inlet port 76 Connection channel 80 Pressure opening 82 Pressure connection 84 Exhaust duct 90 Plate valve 91a V-shaped curved plate 91b Sleeve

Claims (15)

Double diaphragm pump (1) with a mechanical drive mechanism with - A pump housing (10) which has at least one suction connection (72) and at least one pressure connection (82) as well as a first diaphragm chamber (40) and a second diaphragm chamber (50), wherein - in the first diaphragm chamber (40) a first diaphragm (42) a first conveying space (46) from a drive chamber (48) and in the second diaphragm chamber (50) a second diaphragm (52) a second conveying space (56) from an air chamber ( 58), the first and second delivery chambers (46; 56) being connected to the at least one suction connection (72) on the one hand and the at least one pressure connection (82) on the other hand via valve devices (90; 92), wherein - The first membrane (42) and the second membrane (52) can be connected to a coupling rod (68), and - At least one of the membranes (42; 52) can be moved by means of the mechanical drive mechanism, characterized in that
the mechanical drive mechanism comprises a drive piston (120) and a ball joint (112) that can be accommodated therein as well as a receptacle (100) which can be connected to the ball joint (112) and which is designed to be coupled to an output shaft (20) of a drive unit designed as an eccentric shaft . Double diaphragm pump (1) according to Claim 1, characterized in that the drive piston (120) can be detachably connected to the first diaphragm (42) by means of a fastening element (60). Double diaphragm pump (1) according to one of Claims 1 and 2, characterized in that the ball joint (112) can be screwed into a threaded bore (104) formed on the receptacle (100) and is held in a clamping manner. Double diaphragm pump (1) according to Claim 3, characterized in that the threaded bore (104) is slotted, a width of the slot (102) being variable by means of screw means (106). Double diaphragm pump (1) according to one of the preceding claims, characterized in that the ball joint (112) has a threaded shaft (116) for detachable connection with the receptacle (100) and a ball head (114) which is in a drive piston designed as a hollow piston (120) mountable bearing block (130) is mounted, so that a rotary movement of the output shaft (20) is transformed into a longitudinal movement of the drive piston (120) and can be transmitted to one of the membranes (42; 52). Double diaphragm pump (1) according to one of the preceding claims, characterized in that the drive piston (120) has a through bore (124) so that the ball joint (112) can be screwed into the receptacle (100) or out of the receptacle ( 100) can be dismantled. Double diaphragm pump (1) according to one of the preceding claims, characterized in that spring means (140) are received in the drive piston (120) designed as a hollow piston in order to mount the ball joint (112) within the drive piston (120) in a prestressed manner. Double diaphragm pump (1) according to one of the preceding claims, characterized in that the valve devices (90), which can be arranged in a fluid-conducting connection between the delivery spaces (46; 56) and the suction connection (72), are designed as plate valves (90) made of an elastic plastic . Double diaphragm pump (1) according to one of the preceding claims, characterized in that the valve device (92), which can be arranged in a fluid-conducting connection between the delivery spaces (46; 56) and the pressure connection (82), is designed as a flap valve (92) made of an elastic plastic . Double diaphragm pump (1) according to claim 9, characterized in that the flap valve (92) has a V-shape with a hinge shaft (94) which is held in a clamping manner at the base of the V-shape and which can be inserted into a hinge element (95) , which is received in the fluid-conducting connection from the pressure connection (82) to the delivery spaces (46; 56). Double diaphragm pump (1) according to Claim 9 or 10, characterized in that the flap valve (92) can be installed and removed through the pressure connection (82). Double diaphragm pump (1) according to one of the preceding claims, characterized in that the pump housing (10) is designed in several parts, a pump cover (12), a control block (14) and a drive housing (16) being designed such that they can be joined together without sealing means are sealingly connectable. Double diaphragm pump (1) according to claim 12, characterized in that a separating surface between the pump cover (12) and the control block (14) and between the control block (14) and the drive housing (16) is sealed against one another via the membrane (42, 52) which can be arranged in this separating surface is. Double diaphragm pump (1) according to Claim 12, characterized in that the control block (14) is constructed in several parts. Double diaphragm pump (1) according to one of the preceding claims, characterized in that the drive space (48) and the air chamber (58) are connected by means of an air duct (18).

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