EP1373731B1 - Oscillating displacement pump - Google Patents

Abstract

An oscillating displacement pump, particularly a diaphragm pump (P) for liquid or gaseous delivery media, having a delivery space which on the one side is delimited by a pump head and on the other side by a delivery element, particularly formed by a diaphragm ( 6 ). The delivery element is drivingly connected to an eccentric drive, and an inlet valve connected to an inlet connection and an outlet valve connected to an outlet connection are connected to the delivery space. The pump has a pulsation damper ( 45 ) on the pressure side, and also an excess pressure limiting device ( 27 ) between the pressure and suction sides, these devices being integrated into the pump head. In use as a liquid pump, an oscillation chamber ( 16 ) is integrated into the suction side of the pump head. Pressure peaks are thereby diminished both on the suction side and the pressure side, and a pressure rise on the pressure side is limited to a predeterminable value.

Description

The invention relates to an oscillating positive displacement pump for liquid or gaseous media, with a delivery chamber, which is bounded on the one hand by a pump head and on the other hand by a conveying element, which is in drive connection with a lifting drive, wherein to the delivery chamber connected to an inlet port inlet valve and an outlet valve connected to an outlet valve are connected, wherein the pump at least on the pressure side a pulsation damper and between the pressure and the suction side has a pressure relief device, in particular a diaphragm pump with a conveyor element formed by a membrane.

Diaphragm pumps, which are used as liquid pumps but also as gas pumps, operate on the principle of oscillating positive displacement pumps. Naturally, this principle causes pulsation on both the suction and the pressure side.

Pulsation on the suction side can cause cavitation, pressure surges and vibrations in diaphragm pumps and especially in high-speed diaphragm pumps.

The harmfulness of cavitation in liquid pumps is known. In addition, it causes noise and leads to unstable delivery.

Pressure surges can damage or affect the function of devices mounted in the suction line. Vibrations cause noise and are transmitted to peripherals or to the entire device.

Pulsation on the pressure side causes pressure surges and vibrations in diaphragm pumps. The effects are the same as on the suction side but even more radical, because on the pressure side - in contrast to the suction side - the pressure peaks can rise much higher.

With the system closed or plugged, membrane fluid pumps compress a fluid until the weakest link in the chain yields. This will damage this item.

From US-A-2 405 466 a pump of the type mentioned is known. This has a suction-side and a pressure-side damper each with a damping chamber with an air filling. Between the damping chamber and the inlet chamber or the outlet chamber is a disc with one or more openings or of porous material, provided. These partially transparent disks between the air filling and the liquid conveying medium in the inlet chamber or the outlet chamber are intended to prevent the damping air cushion being entrained with the liquid flow.

Such a damping device can only work in a position of use of the pump, where the damping chambers are at the top. In addition, the pump is provided only for conveying liquids and finally the damping chambers for a sufficient damping are still relatively bulky.

Object of the present invention is to provide a positive displacement pump, in particular a diaphragm pump for liquid or gaseous media, in which both the suction side and the pressure side pressure peaks are avoided, which also increased safety requirements and still has a compact design.

To solve this problem, it is proposed that a connection block is provided as part of the pump head, in which at least the pulsation damper, the overpressure limiting device and when used as a liquid pump in the suction-side part of the pump head an oscillating chamber are integrated and which has the inlet nozzle and the outlet, that the Pulsation damper has at least one damping chamber, which is divided by means of a separation membrane into a receiving space for damping elements and in a conveying medium leading area, are arranged within the damping chambers damping elements made of elastic material, that the pressure-side Pulsationsdämpfer is connected via an outlet throttle body with an outlet, which in turn is connected to the pressure-side, the outlet port forming line connection and that connected between the pressure and the suction side of the pump pressure relief device with its pressure side connected to the pressure-side line connection.

The integration of all provided for Pulsationsdämpfung and overpressure limitation facilities in the connection block of the pump head results in a particularly compact design. Connecting lines, which would be required in a remote arrangement of facilities are avoided. In addition, such a terminal block also allows for optimal arrangement of the individual devices and it is possible to provide one or the other device only as needed and thus to take into account an adaptation to different applications as well as unused devices disabled, for example by blind cover. Also, the production is simplified.

By the pressure-side pulsation damper with subdivision of the damping chamber (s) by means of a separating membrane in a receiving space for damping elements and in a conveying medium leading area, the damping elements can not come into communication with the fluid, so that the damping elements used can be tailored exclusively to the required damping properties and a resistance to the respective fluid is not required. As a result, even aggressive fluids can be used easily with appropriate choice of material of the separation membrane. In addition, the pump can be operated independently of position by the separation membrane between the receiving space for damping elements and the conveying medium leading area.

The vibration chamber integrated in the suction-side part of the pump head when used as a fluid pump has a vibration diaphragm which divides the vibration chamber into a chamber part connected to the suction side and a chamber part connected to the ambient air via an opening. When pumping a liquid is not abruptly stopped by this suction-side pulsation damping of the liquid flow when closing the inlet valve, but can be held by the then deflecting vibrating diaphragm something "in the flow". A pulsation on the suction side can thereby also effectively reduced and avoid cavitation, pressure surges and vibrations especially in high-speed diaphragm pumps. In addition, noises are damped and an unstable flow rate is avoided.

The pressure relief device provides pressure monitoring or pressure limiting and protects the pump from damage when the pressure rises due to a closed or clogged system.

The overpressure relief, which is located between the pressure and suction sides of the pump head, is used to set the maximum allowable pressure on the discharge side of the pump or to maintain a constant pressure on the discharge side of the pump regardless of the flow rate.

The present invention thus reduces pressure peaks on both the suction and on the pressure side and limited by the overpressure limiting device, the pressure increase on the pressure side to a predetermined value.

By arranging the pressure-side pulsation damper with its outlet throttle body before the pressure-side connection of the pressure-limiting device, it can be adjusted to the already smoothed pressure, so that pressure peaks no longer have to be taken into account. Pressure peaks only reach the overpressure limiting device in a dampened form, so that the overpressure limiting device can be adjusted more sensitively and more accurately and, in particular, the adjustment can be made very close to the operating pressure.

This also results constructive advantages by a smaller possible construction of the pump because a return flow of fluid through the pressure relief device is much lower or not available and thus the full flow is also effectively available.

If, as is the case in the state of the art according to US Pat. No. 2,405,466, the pressure side of the overpressure limiting device would be subjected to practically unattenuated pressure, there would be a comparatively high reflux and thus a reduced effective pumping capacity.

Accordingly, such a pump would have to be designed for a higher delivery rate to produce a desired effective delivery rate, which, however, increases and increases the cost of the pump.

In particular, in applications where the operating pressure may be exceeded only slightly and thus the DruckeinStellung the overpressure limiting device is close to the operating pressure, the occurring pressure peaks cause the overpressure limiting device responds and a portion of the flow from the pressure side leads back to the suction side, so that accordingly sets a lower efficiency with respect to the flow rate.

These disadvantages are avoided in the pump according to the invention.

Furthermore, the arrangement of the pressure-side Pulsationsdämpfers with its outlet throttle body before the pressure-side connection of the overpressure limiting device in the pump according to the invention advantageous that the damping effect by the throttle integrated into the pump exactly predetermined and thus an accurate adjustment of the pressure relief device before delivery of the pump and allows connection to peripheral devices.

It is preferably provided that the pump head has an approximately cuboid pump head housing, with a connection side for an intermediate plate having the valves, opposite to this connection side with the overpressure limiting device, and that on the four other circumferential sides opposite the inlet port and the outlet port and the pressure side Pulsationsdämpfer and optionally the suction-side vibration chamber are mounted. This is the inputs or attachments - pressure relief, pulsation damper, vibration chamber - the pump head independently accessible and thereby, among other things, easy to assemble and disassemble.

One embodiment of the pressure-side pulsation damper provides that it has at least two series-connected damping chambers within the pump head or a damper housing belonging to the pump head, for this purpose a line section connected to an inlet has a connection channel to a first damping chamber and via an inlet throttle element to a second, connected via an outlet throttle body with an outlet damping chamber is connected.

The series connection of several damper stages achieves a high damping, which increases exponentially with the number of damper stages. The throttle bodies in conjunction with the damping chambers form attenuators, which can caching and releasing medium when pressure fluctuations occur. Through the throttle bodies, a dynamic pressure is built up during a pressure surge, by which a pressure charging of the attenuators and a throttled delivery of fluid in the subsequent pressure phase to the pressure drop phase is possible.

• Eine Explosionsdarstellung einer erfindungsgemäßen Membranpumpe.

Additional embodiments of the invention are set forth in the further subclaims. The invention with its essential details with reference to the drawings is explained in more detail below.
The only figure shows:

• An exploded view of a diaphragm pump according to the invention.

A pump P shown in the figure has a pump housing 1, to which a motor 50 is flanged laterally. A crank drive for a pump diaphragm 6 has two crankshaft bearings 2, an eccentric 3 and a connecting rod bearing 4. A connecting rod 5 has a connection point 15, via which it is connectable to the pump diaphragm 6. Upon rotation of the crank drive, the pump diaphragm is placed in a stroke movement.
On the pump housing 1, an intermediate plate 7 is mounted, between which and the pump diaphragm 6, a pumping chamber is formed. The intermediate plate 7 includes an attached valve plate 8, an inlet valve and an exhaust valve. The intermediate plate 7 and an adjoining terminal block 9 essentially form the pump head.
The terminal block 9 as part of the pump head is formed approximately cuboid in the embodiment. One of the six sides forms a connection side for the intermediate plate. 7
On the opposite side, the functional parts of a pressure-limiting device 27 are shown. This is used to set the maximum allowable pressure on the pressure side of the pump and has a flow connection between Pressure side and suction side, which is closed in normal operation by an overflow valve.
In the exemplary embodiment, a pressure control diaphragm 20 engages in an inner cavity of the connection block 9 and is there sealingly on an opening 28 connected to the suction side. The pressure control diaphragm 20 is pressurized by a spring 21, wherein the pressurization by an adjusting screw 23 is adjustable. A lock nut 24 with washer 25 serves to secure the respective setting of the adjusting screw 23rd
In the assembly position, the inner cavity of the terminal block 9 for receiving the pressure regulating diaphragm 20 and the like is closed by a pressure cover 22 which is held by means of screws 26. Within the recess are still connected to the pressure side opening 29 can be seen.

On two of the other four sides of the terminal block 9 are opposite one hand, a line connection 14 (inlet port) and on the other hand, a line connection 12 (outlet).

The other two peripheral sides of the terminal block have, on the one hand, a pulsation damper 45 connected to the pressure side and, on the other side, a vibration chamber 16.
The pulsation damper 45 has a large damping element 40 and a small damping element 41, which are located in separate damper chambers. The damping elements may be different in terms of their mass and / or their volume.
The two associated damping chambers are, which is not shown in detail, connected to each other via a line section. This line section has a pressure side Inlet with a connection channel to the first damping chamber. About an inlet throttle body, the line section is connected to the second damping chamber, which in turn is connected via an outlet throttle body with an outlet, which in turn is connected to the pressure-side line connection 12.
The damping elements located inside the damping chambers are made of resilient material.
The damping chambers of the pressure-side pulsation damper 45 are divided by means of a separating membrane 42 into a receiving space for the damping elements 40, 41 and into a conveying medium leading area.
In the exemplary embodiment, a damper cover 43 is provided as the outer termination of the pulsation damper 45, which may have a part or the total volume of the damping chambers here. On the other hand, there is also the possibility that the damping chambers are completely integrated in the terminal block 9. With the help of screws 44, the damper cover 43 is held on the terminal block 9.

On the opposite side of the pulsation damper 45 is the vibration chamber 16. This vibration chamber has an inner cavity connected to the suction side in the connection block 9. A vibrating diaphragm 10 divides the vibrating chamber into a chamber part connected to the suction side and a chamber part connected to the environment via an opening 17.
To hold the vibrating diaphragm 10 and as the conclusion of the vibration chamber is a cover plate 11 which is held by screws 13 on the terminal block 9.
By the vibration chamber 16, a suction-side pulsation damper is formed. By different choice of the diameter-thickness ratio of the vibrating diaphragm 10 can the vibration damping can also be optimized depending on the respective pumped medium.

Dash-dotted is still indicated that in the pump head or the terminal block 9, a heater can be integrated. This may, as not shown in detail, a hot plate 30 including cable connections, optionally a heat distribution plate 31 and optionally a Einguß mass 31 include. This can be avoided at appropriate pressure and temperature conditions freezing of the pump head or it can be thawed frozen pump head this.

Claims (12)

1. Oscillating displacement pump for liquid or gaseous delivery media, having a delivery chamber which is delimited on one side by a pump head and on the other side by a delivery element that has a driven connection to a lifting drive, said delivery chamber being attached to an inlet valve connected to an inlet connection piece and an outlet valve connected to an outlet connection piece, the pump (P) comprising, at least on the pressure side, a pulsation damper (45) and an excess-pressure limiting device (27) between the pressure side and the suction side, in particular a diaphragm pump having a delivery element formed by a diaphragm, characterised in that a connecting block is provided as part of the pump head, in which at least the pulsation damper (45), the excess-pressure limiting device (27) and, if the pump is used as a liquid pump, in the suction part of the pump head, an oscillating chamber (16) is integrated, and said connecting block comprises the inlet (14) and the outlet (12), the pulsation damper (45) has at least one damping chamber which is divided by a separating diaphragm into a receiving chamber for damping elements (40, 41) and into an area conveying delivery medium, in that damping elements (40, 41) made of springily elastic material are arranged inside the damping chambers, in that the pulsation damper (45) on the pressure side is connected, via an outlet throttle member, to an outlet which is in turn connected to the line connection (12) on the pressure side, forming the outlet connecting piece, and in that the excess-pressure limiting device (27) connected between the pressure and suction sides of the pump is connected on its pressure side to the line connection (12) on the pressure side.
2. Pump according to claim 1, characterised in that the excess-pressure limiting device (27) between the pressure and suction sides of the pump is adjustable in order to achieve the maximum permissible pressure on the pressure side of the pump.
3. Pump according to claim 1 or 2, characterised in that the excess-pressure limiting device (27) has a connection between the pressure side and the suction side of the pump and that an overflow valve (20, 28) which is preferably adjustable in terms of its response pressure is inserted in this connection.
4. Pump according to claim 3, characterised in that the adjustable overflow valve of the excess-pressure limiting device (27) has a spring-biased pressure regulating diaphragm (20), the spring bias acting on which can be varied by means of an adjustment screw (23).
5. Pump according to one of claims 1 to 4, characterised in that the pump head has a substantially cuboid pump head housing (connecting block 9), with a connecting side for an intermediate plate (7) comprising the valves, located opposite this connecting side with the excess pressure limiting device (27), and in that opposite the other four circumferential sides are mounted the inlet connection piece (14) and the outlet connection piece (12) as well as the pulsation damper (45) on the pressure side and optionally the oscillating chamber (16) on the suction side.
6. Pump according to one of claims 1 to 5, characterised in that the pulsation damper (45) on the pressure side comprises at least two damping elements (40, 41) which differ in their mass or materials and/or damping chambers which differ in their volumes.
7. Pump according to one of claims 1 to 6, characterised in that the pulsation damper (45) on the pressure side comprises at least two damping chambers connected in series within the pump head or a damper housing (43) belonging to the pump head, and for this purpose a line section attached to an inlet comprises a connecting channel to a first damping chamber and, through an inlet throttle member, is connected to a second damping chamber which is connected to an outlet via an outlet throttle member.
8. Pump according to one of claims 1 to 7, characterised in that the head cover of the diaphragm pump is constructed as a connecting member such that functional chambers of the components (excess-pressure valve, oscillating chamber) are integrated in this connecting member.
9. Pump according to one of claims 1 to 8, characterised in that the pulsation damping chamber or chambers of the pulsation damper (45) on the pressure side is or are constructed both as a head cover for the pump and as a connecting member to the oscillating chamber and to the overflow valve.
10. Pump according to one of claims 1 to 9, characterised in that the oscillating chamber (16) on the suction side comprises an oscillating diaphragm (10) which divides the oscillating chamber into a chamber portion connected to the suction side and a chamber portion connected through an opening (17) to the atmosphere.
11. Pump according to claim 10, characterised in that the oscillating diaphragm (10) of the oscillating chamber on the suction side is matched, in terms of its diameter to thickness ratio, to the particular delivery medium in order to achieve optimum damping of the oscillations.
12. Pump according to one of claims 1 to 11, characterised in that a heater (30, 31, 32) is integrated in the pump head.

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