EP3851674B1 - Double membrane pump - Google Patents

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 pump fluids, especially liquids and gases. In general, a diaphragm pump has a diaphragm arranged in a diaphragm chamber, 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 pumped. The membrane is set in motion by a hydraulic, pneumatic, mechanical, or electromagnetic drive mechanism. A mechanical diaphragm pump generally shows higher efficiency, lower pulsation and universal applicability 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 include a pump housing with two parallel line sections, which form a first diaphragm chamber and a second diaphragm chamber. A membrane is arranged in each of the membrane chambers, sealingly separating 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 membrane type, the membranes can be coupled to a connecting shaft, also referred to as a coupling rod, and move synchronously. Also known are independent drive means for the membranes, which can be synchronized by means of a controller.

Movement of the membranes changes the volumes of the conveying or fluid chamber and the drive chamber in a complementary manner 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 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. In 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 requirement. Diaphragm pumps of this type 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 that move back and forth in unison, i.e. synchronously with one another, in order to alternately fill and evacuate the delivery chamber, have the disadvantage that periodically recurring delivery pressure drops occur 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 conveying pressure shows a sawtooth-shaped progression over time.

It is known to operate diaphragm pumps with compressed air, which requires the use of expensive compressed air that is only available in limited quantities. Accordingly, a specially coordinated Infrastructure to make compressed air available at the place of use, so that mobile use of the diaphragm pump is problematic.

Electromechanically operated double diaphragm pumps are known, with a piston rod being operatively connected to a crank pin which is arranged at a free end of an output shaft of a geared motor. In this way, a rotary movement emanating from the drive motor is converted into the linear movement of the piston rod or the membranes 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 lifetime of the diaphragm pump, signs of wear and mechanical defects in the diaphragm often lead to pump failure. Known membranes are made of a material with a certain elasticity, for example elastomers such as NBR (acrylonitrile butadiene rubber). Also known are composite membranes in a sandwich construction with a layer of an elastomer and another 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 simultaneously 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 structured membrane during pumping operation. Molded and structured diaphragms can have a Teflon coating on their three-dimensional surface on the medium side.

Out of AT 34 296 B a multi-chamber diaphragm pump is known. Here, several membrane pumps are arranged one above the other, which are actuated by means of a common rod with a crank drive. The respective conveying chambers are connected via a chamber to a suction line and via a further chamber to a pressure line, with openings being able to be closed via replaceable suction or pressure flaps.

Out of U.S. 3,027,848 A a diaphragm pump is known which can be actuated by means of a piston rod, the piston rod being connectable to a drivable crank pin via a ball joint.

Out of U.S. 2,918,878 A a counter-rotating double diaphragm pump with a manually operable drive mechanism for moving the diaphragms is known.

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 wearing parts are easy to replace, with sealants not being required 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 solids content. In addition, the double membrane pump is characterized by high efficiency and almost vibration-free operation, so that the good stability allows universal use.

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

Although the invention relates to a double membrane pump, other membrane pumps with a mechanical drive mechanism are also fundamentally included.

The double membrane 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 membrane chamber and a second membrane chamber. In the first membrane chamber, a first membrane 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. If both membranes can be moved by a mechanical drive mechanism, the second membrane chamber is a mirror image of the first membrane chamber. The conveying chambers are connected to at least one suction port on the one hand and the pressure port on the other hand via valve devices. Furthermore, the first membrane and the second membrane can be connected to a coupling rod. Through the mechanical
Coupling involves 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 be reassembled for use in a reverse orientation, if necessary.

The mechanical drive mechanism of the double membrane pump comprises a drive piston and a ball joint that can be accommodated therein, as well as a receptacle that can be connected to the ball joint and is designed to be able to be coupled to an output shaft of a drive unit designed as an eccentric shaft. The receptacle is also designed such that the ball joint can be screwed into a threaded bore and is clamped therein.

Accordingly, a membrane chamber is formed in two parallel line sections in the pump housing, in which freely oscillating membranes are arranged, so that a product or fluid chamber, referred to as the conveying 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 membranes move in the other air chamber or the drive chamber, an increasing and decreasing back pressure is generated. This back pressure supports the movement of the membranes and serves to compensate for thermal effects and pumping effects.

The two membranes, also referred to as the first membrane and the second membrane, are connectable 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 secured to the membranes in each case. For this purpose, a fastening element is provided on each of the membranes in a central zone, for example vulcanized, which on the one hand serves to detachably attach the coupling rod to the respective diaphragm and on the other hand to axially secure one of the diaphragms relative to or to detachably attach to the drive piston of the mechanical drive mechanism. For this purpose, each fastening element can have an internal thread into which an external thread is formed at the 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 screws has the advantage that the assembly is easy to handle, is inexpensive and can be dismantled, and also allows adjustability in order to set a delivery volume. The fastening element is preferably designed in the form of a disk, the diameter being selected in such a way that it largely covers a central zone of the membrane. In particular, the fastening element is made of metal, so that a dimensionally stable and precise fastening on the one hand of the coupling rod and on the other hand of the drive component of the drive mechanism is possible.

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

A drive unit, for example a motor, which can be coupled to the mechanical drive mechanism, is provided for moving the membranes. 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, with 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 accommodated in the receptacle. The recording includes on a side surface and thus perpendicular to the axis of Output shaft has a threaded bore into which a component of the drive mechanism designed as a ball joint can be screwed and held in a clamped position. The ball joint can be designed in such a way that it has a ball head and a threaded shank extending therefrom, at the free end of which a threaded area is formed. The ball joint is designed to transfer the movement originating 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 the width of the slot being variable by means of screwing means. In a loosened state, the screwing 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, determine the adjustable or set position.

The ball joint is accommodated in the drive piston, which can be connected to one of the diaphragms and is slidably accommodated 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 there is an arrangement with dry lubrication.

The ball joint or the ball head is mounted in a bearing block that can be accommodated in the drive piston, so that a rotational 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 made in several parts and can be positioned within the drive piston. For example, the bearing block can bear against insert parts, for example cylindrical spacers, accommodated in the drive piston. Alternatively, end faces of the bearing block suitably designed stops 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 using an insertable tool. In this case, a tool holder can be formed on the ball head, into which a tool that can be inserted through the through bore engages and can be connected to the ball joint in a rotationally fixed manner. This through-hole serves to enable the components of the mechanical drive mechanism to be dismantled.

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

In a preferred embodiment, spring means can be accommodated in the drive piston, between which the ball joint can be mounted in a prestressed manner. The position of the ball joint is therefore pretensioned, so it can always be reset to an initial position. The resetting takes place against a spring force of one of the spring means. By arranging the spring means within the drive piston, a compact design with a reduced installation space can be implemented. The arrangement of the spring means allows a type of overload protection, which enables the automatic return of the ball joint and thus the drive piston to a starting position.

The spring means or means can be designed in the form of spiral springs or cup springs, with a free spring length being adjustable to the stroke of the drive piston. Since limited rotational movement of the ball joint about its longitudinal axis but no movement in the direction of the longitudinal axis is possible, the ball joint provides power transmission with a stable, centered bearing, which prevents tilting or snaking.

In one embodiment of the double diaphragm pump, the valve devices can be arranged in fluid-conducting connections of the pumping chambers to the at least one suction port on the one hand and to the at least one pressure port on the other. Accordingly, a passive valve device can be arranged on at least one suction opening provided in each conveying space, which valve devices open when the associated membrane is suction-moved. In one embodiment, the valve device that can be used is designed as a plate valve made of an elastic plastic. The movable valve plate can be connected to a plug, which can be accommodated in a connecting channel at the respective suction opening. Depending on the position of the plate valve, a fluid-conducting connection between the pumping chamber and the suction port can be opened or closed.

Furthermore, in the fluid-conducting connection of the conveying chambers to 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 used 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 conveying chambers 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, with a hinge shaft being clamped 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 flapper valve can be installed and removed through the pressure connection. Here, at least the hinge element is firmly fixed in position and the hinge shaft, held clamped in the V-shape of the wings, can be pressed into receptacles on the hinge element.

In a further embodiment, the pump housing is designed in several parts, with a pump cover, a control block, in which the suction port for sucking in a fluid to be pumped and the Pressure connection are provided for the exit of the pumped fluid and includes a drive housing and are sealingly connected to each other.

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 that is chemically inert and resistant to the medium to be pumped. Alternatively, however, a design made of metal is also conceivable.

One of the membrane chambers, referred to here as the second membrane chamber, can be formed by the pump cover and the control block, and the other of the membrane chambers, the first membrane chamber, is formed between the control block and the drive housing. Circular depressions can be formed on the parallel outer surface of the control block, each of which is arched over by one of the membranes. In particular, a circumferential groove is provided concentrically around the circular depression on each of the two outer sides of the control block, in which groove a peripheral annular bead of the respective membrane can be accommodated. 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 from one another by 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 an even application of force.

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

The control block comprises a suction block with the suction port and inlet channel and connecting channels, a pressure block with the pressure port and outlet channel and connecting channels and a central block designed to accommodate the coupling rod. In a suction area, the at least one suction connection is in fluid-conducting connection via an inlet channel and a respective connecting 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 conveying direction is determined by the position of the valve devices. For example, the connecting channels can be T-shaped in the suction area and V-shaped in the pressure area.

The membranes that can be used are designed to be sufficiently dimensionally stable so that they are not deformed during pump operation by the opposing compressive forces acting on opposite sides of the membrane, thereby reducing performance. In particular, each membrane is designed as a structured membrane. A membrane core can be provided in a central zone of the membrane, which brings about 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 include one or more zones, each of which fulfills a different function. Thus, the membrane on the outer circumference comprises the annular bead mentioned and thus a clamping zone, via 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 off from the environment and from the drive mechanism in the area of the medium to be pumped without additional sealing means.

One or more radial zones of the membrane can adjoin between the clamping zone and the central zone, which are convex and/or concave in shape when the membrane is not under load and, for example, fulfill a support function and/or a balancing function. This enables the membrane to be guided as safely and with as little vibration as possible. This also promotes low-noise operation.

Furthermore, the membranes on the side of the fluid or conveying space are made of a material that is largely insensitive to aggressive chemicals in particular. Thus, 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 low gas permeability. For the product side, plastics with a high level of resistance, including resistance to mineral oils and chemicals, as well as good technological properties such as swelling resistance, elasticity and resistance to compression deformation are suitable.

Due to the design of the mechanical drive mechanism and its connection to the membranes, the double membrane pump according to the invention can be easily dismantled into its individual parts. In addition, wearing parts, such as valve devices, can be easily replaced if necessary without having to completely dismantle the double diaphragm pump. Diaphragms and valve devices can be exchanged separately from one another by means of separate access options.

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 according to a partially sectioned perspective view of the double diaphragm pump 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 designed in several parts in the illustrated embodiment. It therefore 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 servo motor, or a conventional drive motor or air motor. An output shaft 20 of the drive unit, designed as an eccentric shaft, can be held in bearings in the drive housing 16 and is operatively connected to a mechanical drive mechanism that is still to be described. The rotational movement of the output shaft 20 of the drive unit is thus transformed into a translatory movement of the mechanical drive mechanism, ie into a sinusoidal movement. On one of the side surfaces of the pump housing 10, an opening 30 is shown schematically, which marks an inlet or an outlet for the fluid to be pumped. The pump housing 10 or parts thereof can be made of a plastic, for example polytetrafluoroethylene or another chemically inert material.

figure 2 shows a longitudinal section through the double membrane pump 1. The membrane pump shown as a double membrane pump 1 is not limited to an embodiment as a double membrane pump, rather its technical principles can be transferred to any conceivable embodiment of a membrane pump.

As indicated in figure 2 the drive unit (not shown) can be releasably attached 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 mounted there. Furthermore, the eccentric formed on the output shaft 20 is in contact with a receptacle 100 or is accommodated 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 below Figures 3 , 9 and 10 is referenced. The mechanical drive mechanism includes drive components, which are designed as a connecting rod or a push 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 double diaphragm pump 1 shown 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 membrane chamber 40 and in the second membrane chamber 50, a membrane 42, 52 are arranged in a freely swinging manner. The membranes 42, 52 each have a peripheral annular bead 44, 54 which is compressed between the drive housing 16 and the control block 14 or between this and the pump cover 12 in a correspondingly designed clamping area and is held there in a sealing manner. In the first membrane chamber 40, the membrane 42 separates a first delivery space 46 from a drive space 48 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 duct 18 is set up such that during a suction movement, for example of the membrane 42 in the first membrane chamber 40 , air is pressed out of the drive space 48 into the air chamber 58 of the second membrane chamber 50 . In this way and due to the small diameter of the air channel 18, a pressure builds up in the membrane chamber 50, which supports the pressure movement of the second membrane 52 and vice versa.

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

In each of the membranes 42; 52 is a fastener 60 in a central zone of the membranes 42; 52 recordable, eg embedded. The fastener 60 may be formed with a lug through one in the central zone of the membranes 42; 52 provided opening is performed. Furthermore, a disc-shaped area can be formed on the fastening element 60, which this opening or the central zone of the membranes 42; 52 covered and applied to this. The attachment of the fastening element 60 is designed as a component of a screw connection, ie it has 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 serves to detachably 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 the rigid connection of the first membrane 42 and the second membrane 52 can be screwed. The arrangements of the threads can also be reversed. The parts can be detached and disassembled from one another in a simple manner by means of the screw connections provided, so that an exchange of one of the membranes 42; 52 is easy to carry out. Other types of connection of 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 positive fit, for example the coupling rod 68 can be connected to at least one of the membranes 42; 52 be overmoulded.

In the figure 2 are the membranes 42; 52 is designed as a structural membrane, with several zones being able to be formed between the central zone and the annular bead 44, which zones have different functions. For this purpose, in the direction of conveying space 46; 56 concave and/or convex 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 to prevent sagging the diaphragm 42; 52 via the suction or pressure openings in the conveying chambers 46; 56 is reduced or abolished.

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

In the conveyor rooms 46; 56 of the first membrane chamber 40 and the second membrane chamber 50, at least one suction opening 70 and one pressure opening 80 is formed. A valve device designed as a plate valve 90 is accommodated at each suction opening 70 and determines the conveying direction of the fluid or medium to be conveyed. 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 into the conveying chamber 46; 56 of the diaphragm 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 given in figure 7 shown.

The pumped fluid is in a pressure movement of the membrane 42; 52, in which the corresponding plate valve 90 has the suction opening 70 in the delivery chamber 46; 56 closes, conveyed via the pressure opening 80, the connecting 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 a crossing 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 delivery chambers 46; 56 is squeezed out. Details of the flapper valve 92 are 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 of figure 3 also shows that a seal 122 is provided on an outer circumference of the drive piston 120, which seals the associated drive chamber 48.

The Figures 4 and 5 each show different phases of the assembly of a double diaphragm pump 1 according to one embodiment. In the Figures 4 and 5 the control block 14 is shown at least partially in section and shows its interior. The respective connection channels 76 are visible, which establish 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 pumping fluid into or out of the first pumping space 46 of the first membrane chamber 40 and the second pumping space 56 of the second membrane chamber allow 50. The conveying direction of the fluid to be conveyed or conveyed is determined by the movement of the membranes 42; 52 (not shown) conditional position of the valve devices 90, 92 specified. The plate valves 90 can be arranged at the respective suction openings 70 in the suction region in which the suction connection 72 is located. The plate valve 90 can be inserted in the connection 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 pumping chamber 46; 56. Meanwhile, in the pressure area, a fluid-conducting connection between the pumping chamber 46 or 56 to be filled and the pressure connection 82 is blocked by the flap valve 92 arranged there. With 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 pumping 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 bent in a V shape and preferably made of an elastic material or plastic. A bore is provided on one side of the V-shaped plate 91a, in which a sleeve 91b is held, which can be inserted into the suction opening 70 or the connecting channel 76.

Out of figure 7 1 shows a perspective view of the flapper valve 92. The flapper valve 92 is designed in a V-shape and has two flapper blades 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 parts that are subject to high thermal and mechanical loads. At the base of the V-shape of the flapper valve 92 is supportingly received a hinge shaft 94 which projects with free ends beyond the vanes 93a, 93b. The free ends of the hinge shaft 94 are connected to a hinge element 95 ( figure 4 ) lockable, and freely rotatable therein, so that the flapper valve 92 can perform a tilting movement. The hinge element 95 is held firmly 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 establish one of the fluid-conducting connections to the conveying chambers 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, designed here as a ball bearing. The receptacle 100 forms a kind of connecting rod with a ball joint 112, which is regarded as a component of the mechanical drive mechanism. The receptacle 100 corresponds to a certain extent to a connecting rod head and is largely cuboid in shape. A slot 102 is formed on one of the side surfaces of the receptacle 100 and runs parallel to a base surface of the receptacle 100 and thus perpendicularly 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. Screw means 106 are provided for this purpose, which change the width of the slot 102 depending on the position. The ball joint 112 comprises a ball head 114 at one end, from which a threaded shank 116 extends, at the end of which a threaded area complementary to the threaded bore 104 is formed. In the illustrated embodiment, the ball joint 112 is formed in one piece, a multi-part design is also conceivable. Thus, the ball joint 112 can be threaded into the socket 100 and clamped in place with the width of the slot 102 adjusted accordingly.

On the ball head 114 as an extension of the threaded shaft 116, a tool holder 118 is formed, in which a tool can be accommodated in a twist-proof manner. Accordingly, the ball joint 112 can be detached from the receptacle 100 when the screw means 106 are loosened. Thus, a simple adjustment of the tension of the membrane 42 connectable 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 shank 116 , ie screwed into the slotted threaded bore 104 . The output shaft 20 designed as an eccentric shaft is accommodated in the bearing 110 .

The ball head 114 of the ball joint 112 is accommodated in the drive piston 120 . For this purpose, the ball head 114 is rotatably mounted in a multi-part bearing block 130, which is accommodated in the drive piston 120 designed as a hollow piston, for example adjacent to one or more insertable spacers (not shown). In the embodiment shown, the drive piston 120 has a multi-part design, with the parts being able to be connected to one another by means of a screw connection 121 . The drive piston 120 has a through hole 124 on an end face. A tool can be passed through the through hole 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 accommodated in the drive piston 120, spring means 140 can be arranged, which enable the multi-part bearing block 130 to be held in a prestressed manner. In particular, the multi-part bearing block 130 is arranged between spring means 140 so that it can always be returned to its initial position. In this way, a type of overload protection is created, which allows the mechanical drive mechanism and the first membrane 42 and second membrane 52 connected thereto to be reset. Alternatively, the overload protection can also be designed in the form of an electronic overload protection. Reference sign 1 double diaphragm pump 92 flap valve 10 pump housing 93a,b damper wings 12 pump cover 94 hinge shaft 14 control block 95 hinge element 16 drive housing 18 air duct 100 Recording 20 output shaft 102 slot 104 threaded hole 30 opening 106 screw means 40 first membrane chamber 110 camp 50 second membrane chamber 112 ball joint 114 ball head 41 membrane core 116 threaded shank 42 first membrane 118 tool holder 44 ring bead 120 drive piston 46 first promotion room 121 screw connection 48 drive room 122 poetry 124 through hole 52 second membrane 54 ring bead 130 storage block 56 second conveyor room 58 air chamber 140 spring means 60 fastener 62 inner thread 64 cover element 66 second internal thread 68 coupling rod 70 suction port 72 suction port 74 inlet channel 76 connecting channel 80 pressure port 82 pressure connection 84 exhaust port 90 plate valve 91a V-shaped curved plate 91b sleeve

Claims (14)

1. Double membrane pump (1) with a mechanical drive mechanism with

   - a pump housing (10) which has at least one suction port (72) and at least one pressure port (82) as well as a first diaphragm chamber (40) and a second diaphragm chamber (50), whereby

   - in the first diaphragm chamber (40) a first membrane (42) separates a first conveying chamber (46), able to be loaded with fluid to be conveyed, from a drive chamber (48), in which a drive mechanism is able to be arranged, and in the second diaphragm chamber (50) a second membrane (52) separates a second conveying chamber (56), able to be loaded with fluid to be conveyed from an air chamber (58), able to be pressurized with air, whereby

   - the first membrane (42) and the second membrane (52) are connectible with a coupling rod (68), and

   - at least one of the membranes (42; 52) is movable by means of the mechanical drive mechanism,

   whereby
   the first conveying chamber (46) and the second conveying chamber (56) are alternately connectible to the at least one suction port (72) via a valve device (90) and to the at least one pressure port (82) via a valve device (92), respectively,
   characterized in that
   the mechanical drive mechanism comprises a drive piston (120) and a ball joint (112) able to be accommodated therein, as well as a receptacle (100) connectible to the ball joint (112), which receptacle is designed to be able to be coupled to a drive shaft (20), designed as eccentric shaft, of a drive unit and whereby the ball joint (112) is screwable into a threaded bore (104) of the receptacle (100) and is held therein in a clamped way.
2. Double membrane pump (1) according to claim 1, characterized in that the drive shaft (120) is connectible in a releasable way to the first membrane (42) by means of a fixing element (60).
3. Double membrane pump (1) according to claim 1 or 2, characterized in that the threaded bore (104) is designed slotted, whereby a width of the slot (102) is variable by means of screwing means (106).
4. Double membrane pump (1) according to one of the preceding claims, characterized in that the ball joint (112) has a threaded shaft (116) for releasable connection to the receptacle (100) and a ball head (114), which is borne in a bearing block (130) that is able to be received in the drive piston (120) designed as hollow piston, so that a rotary movement of the drive shaft (20) is transformed into a longitudinal movement of the drive piston (120) and is able to be transmitted to one of the membranes (42; 52).
5. Double membrane pump (1) according to one of the preceding claims, characterized in that the drive piston (120) has a through hole (124), so that, using an insertable tool, the ball joint (112) is able to be screwed into the receptacle (100) or respectively disassembled from the receptacle (100).
6. Double membrane pump (1) according to one of the preceding claims, characterized in that spring means (140) are accommodated in the drive piston (120) designed as hollow piston, in order to bear the ball joint (112) in a pretensioned way inside of the drive piston (120).
7. Double membrane pump (1) according to one of the preceding claims, characterized in that the valve devices (90), arrangeable in a fluid-conducting connection of the conveying chambers (46; 56) with the suction port (72), are formed as plate valves (90) made of an elastic plastic material.
8. Double membrane pump (1) according to one of the preceding claims, characterized in that the valve device (92), arrangeable in a fluid-conducting connection of the conveying chambers (46; 56) with the suction port (82), is formed as flap valve (92) made of an elastic plastic material.
9. Double membrane pump (1) according to claim 8, characterized in that the flap valve (92) has a V shape, with a hinge shaft (94) which is held in a clamped way at the base of the V-shape and which is insertable into a hinge element (95) which is received in the fluid-conducting connection from the pressure port (82) to the conveying chambers (46; 56).
10. Double membrane pump (1) according to claim 8 or 9, characterized in that the flap valve (92) is able to be mounted and dismounted by means of the pressure port (82).
11. Double membrane pump (1) according to one of the preceding claims, characterized in that the pump housing (10) is designed in multiple parts, whereby a pump cover (12), a control block (14) and a drive housing (16) are designed in such a way that they are able to be connected to one another in a sealing manner without sealing means.
12. Double membrane pump (1) according to claim 11, 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 off from one another by means of the membrane (42, 52) which can be arranged in this separating surface in each case.
13. Double membrane pump (1) according to claim 11, characterized in that the control block (14) is designed in multiple parts.
14. Double membrane pump (1) according to one of the preceding claims, characterized in that the drive chamber (48) and the air chamber (58) are connected by means of an air duct (18).

Images