CN105422906B

CN105422906B - Diaphragm valve

Info

Publication number: CN105422906B
Application number: CN201510575943.1A
Authority: CN
Inventors: A.格尔布曼
Original assignee: Festo SE and Co KG
Current assignee: Festo SE and Co KG
Priority date: 2014-09-11
Filing date: 2015-09-11
Publication date: 2019-12-10
Anticipated expiration: 2035-09-11
Also published as: DE102014013392A1; CN105422906A

Abstract

The invention relates to a diaphragm valve, comprising: a lower housing portion having a valve body; a housing upper part fixed at the housing lower part; a diaphragm working with the valve body; a spindle connected to the diaphragm and axially adjustable; and a pressure piece for applying pressure to the membrane, wherein the mandrel and the pressure piece are connected to each other in a non-releasable manner.

Description

Diaphragm valve

Technical Field

The invention relates to a diaphragm valve (membranvetentil) having a housing lower part with a valve body, a housing upper part which is fixed to the housing lower part, a diaphragm which works together with the valve body, an axially adjustable spindle (Spindel) which is connected to the diaphragm, and a pressure piece (Druckst ü ck) which exerts a pressure on the diaphragm.

Background

DE 102008045857 a1 discloses a diaphragm, the peripheral edge of which is welded to the valve body, wherein the diaphragm can be latched to an intermediate piece (Zwischenst ü ck) or to a pressure piece, wherein the spindle is screwed into the intermediate piece, so that a pressure and a tensile force can be exerted on the intermediate piece.

DE 3935171 a1 discloses a diaphragm valve in which a diaphragm is welded to a pressure piece part and the edge of the diaphragm is clamped in a valve housing. Such a construction is disadvantageous for the cleanliness required by 3A (hygiene standards, for example in the pharmaceutical and food industry) in the case of leakage, since it has a large number of gaps (Spalt) and undercuts (hinderschneidung). This also corresponds to the case in the assembly according to document EP 2450605 a2, in which the pressure piece is movably connected with the spindle via a transverse pin (querstrift).

Disclosure of Invention

The object of the invention is therefore to provide a diaphragm valve which can be cleaned more easily and has a more uniform force distribution from the pressure piece to the diaphragm.

This object is achieved according to the invention for a diaphragm of the type mentioned at the outset in that the mandrel and the pressure piece are connected to one another in a non-releasable manner.

The diaphragm valve according to the invention has a lower housing part and an upper housing part, between which the diaphragm is arranged (as in the prior art). In order to be able to position the membrane not only easily but also precisely, the lower housing part is provided with a receiving basin (Aufnahmetopf) which partially protrudes from the lower housing part and extends in the direction of the upper housing part. The diaphragm is placed into the receiving basin so that it can rest on the valve flap. The inner diameter of the receiving basin corresponds to the outer diameter of the diaphragm and is prevented from radial movement and/or rotation by a torsion element (Verdrehmittel), for example a nose (Nase), in particular. The upper part of the housing is fixed at the receiving basin, thereby defining its position with respect to the membrane. In the upper part of the housing, there is a retaining element (Halteelement) which engages with its side facing the diaphragm into the receiving pot and is likewise positioned by the receiving pot. The holding element presses the circumferential edge of the membrane forming the tensioning point (einspan) against the lower housing part and clamps it at the valve body. Furthermore, a pressure piece is present above the membrane, which can be moved axially in the direction of the membrane by means of the spindle, so that the membrane can be pressed onto the valve lug and the valve closed. The spindle is supported in its part in the housing upper part in a fluid-tight manner and is guided in an axially displaceable manner. The mandrel and the pressure piece are connected to one another in a non-releasable, in particular material-fit manner (e.g. adhesively bonded or welded) and thus form a rigid component. A uniform force distribution to the membrane and the sealing seat (dichtstitz) or the valve lug is ensured while maintaining the respective component tolerances of the housing and the spindle. Furthermore, the wear of the membrane is uniform, wherein the membrane can be made of rubber or two-part with a cover plate (Schild), for example of a thermoplastic, in particular PTFE. The non-releasable connection of the spindle to the pressure piece results in a non-lost assembly in which the parts are coordinated with each other. Finally, the cleanliness of the diaphragm valve in case of leakage or maintenance can be easily achieved.

The mandrel and the pressure piece can be made of metal and/or plastic, wherein they can have different metals or plastics. The plastic can also be glass-or metal-fiber reinforced.

The connection of the mandrel to the pressure piece can be achieved in different ways in the diaphragm valve according to the invention, for example by means of an ultrasonic welding method, by means of laser welding, by means of hot firing (Heizbacken), by means of spin welding (rotanschwei beta en) or by means of adhesive bonding (klebeverbindeng) or bonding to plastic solvents (L ö sungstetlverklebeng).

In a further development of the invention, it is provided that the pressure piece is provided with an axial bore at its end facing the membrane. A dome (Dom) can be engaged in the hole, the dome being located on the upper side of the membrane and the head of the fixing bolt (befestigungsschaube) being injected into the dome. The fixing screw projects axially in the direction of the pressure piece and can be screwed into the free end of the spindle.

the bore is designed as a blind bore according to the invention and serves to receive a nut. The fastening screw is screwed into the nut, whereby the membrane is fastened to the pressure piece and the spindle.

A particularly preferred embodiment of the invention provides that the nut is retained in the blind hole in a captive manner. When the diaphragm valve is disassembled, in particular when the diaphragm is replaced, there is no need to worry about the loss of components of the structural unit consisting of the pressure piece and the mandrel. This is advantageous in particular in the case of field maintenance.

In a further development of the invention, the blind hole has a radial gap (Verstemmung) or a radially inwardly projecting nose or a radially outwardly pointing groove at a distance from its base. The nut is thereby held in a captive manner and is nevertheless inserted axially displaceably into the spindle.

A simple variant of the invention provides that the pressure piece has a bore, in particular a blind bore, at its side facing the spindle for receiving the free end of the spindle. The nut is inserted into the spindle and then the free end of the spindle is engaged with a precise fit into the bore of the pressure piece before it is connected, for example welded, with the pressure piece. The nut is now held in a captive manner and the force is transmitted rigidly from the spindle to the pressure piece.

In order to be able to connect the pressure piece to the membrane in a simple manner, the bore is designed as a stepped bore (Stufenbohrung) and allows a threaded pin (gewindstift) or a fastening bore (befstigngsbohhrung) to pass through. The threaded pin engages into a nut contained in the spindle. The threaded pin (which has a head, in particular at its free end) is secured in particular in the diaphragm in a loss-proof and rotation-proof manner.

Drawings

Further advantages, features and details of the invention emerge from the figures and the following description, in which an embodiment is described in detail.

Wherein:

Fig. 1 shows a longitudinal section through a first embodiment of a diaphragm valve; and

Fig. 2 shows a longitudinal section through a pressure piece with a mandrel.

Detailed Description

In fig. 1, a diaphragm valve is designated by reference numeral 10, which has an inlet 12 and an outlet 14 and is traversed by a fluid. The inlet 12 and outlet 14 are shown only by way of example. Between the inlet 12 and the outlet 14 there is a valve tab 16, against which a diaphragm 18 can be pressed. The diaphragm 18 is moved axially by a spindle 20 (which is driven in its turn by a pneumatic or electric drive, not shown) between an open and a closed position in which the spindle holds the valve open (as shown) or presses the diaphragm 18 against the valve lug 16, thereby closing the valve.

The diaphragm valve 10 has a lower housing part 22 in which the valve web 16 is located and which is open upward around the valve web 16, so that the valve web 16 can be passed by the fluid from the inlet 12 in the direction of the outlet 14. The valve flap 16 is surrounded by a receiving cup 24, in which the membrane 18 is supported, the surrounding edge 26 of which is located in a receiving groove 28. On the membrane 18, a pressure piece 30 is placed, which is connected to the spindle 20 and can be pressed axially onto the membrane 18 via the spindle, so that the membrane 18 rests sealingly on the valve web 16.

It is also possible to identify that the pressure piece 30 is enclosed and held in place by a holding element 32, which is likewise located in the receiving basin 24 and rests with its lower axial end on the upper side of the circumferential edge 26 of the membrane 18. The circumferential rim 26 of the hammer type engages into the circumferential groove of the holding element 32 and is additionally secured by the groove.

Both the holding element 32 and the pressure piece 30 with the spindle 20 are located in a housing upper part 34, which is connected, for example screwed, in a fluid-tight manner to the receiving pot 24. In the housing upper part 34, the spindle 20 is guided movably in the axial direction and is sealed off from the outside. Furthermore, the housing upper part 34 fixes the holding element 32, thereby securing the circumferential edge 26 of the membrane 18 at the housing lower part 22.

Fig. 2 shows the spindle 20 and the pressure piece 30 in an assembled state. The pressure piece 30 has a stepped bore 36 on its upper side facing away from the diaphragm 18, the lower free end 38 of the spindle 20 being inserted with a precise fit into the larger diameter of the upper part of the stepped bore. The free end 38 is provided with a blind hole 40 which has a radially extending indentation 44 at the periphery, into which a nut 42, for example a hexagonal nut, is axially inserted. The nut 42 is held by the spindle 20 in a rotationally fixed manner, although it is axially displaceable. In this case, the nut 42 is dimensioned such that it cannot leave the stepped bore 36 after the free end 38 of the spindle 20 has been placed on the pressure piece 30 or after insertion into the stepped bore 36, since the smaller diameter of the stepped bore is smaller than the diameter of the nut 42.

In the assembled position shown in fig. 2, the sections of the spindle 20 and the pressure piece 30 inserted into one another are welded to one another and united to form a non-releasable structural unit. In which the nut 42 is retained against loss.

It can also be seen in fig. 1 that the diaphragm 18 has a central dome 46 projecting in the direction of the spindle 20, which is dimensioned such that it can engage in a bore 48 which is provided at the underside of the pressure piece 30, i.e. on the end facing the diaphragm 18. The hole 48 is formed by a lower portion of the stepped hole 36 and has a larger diameter than at an upper side of the stepped hole 36.

The head 50 of the fixing screw 52 which is injected into the membrane 18 is located in the membrane 18. The fastening bolt is held in a rotationally fixed manner in the diaphragm 18 and projects in the direction of the pressure piece 18 and can be screwed via the diaphragm 18 into the free end 38 of the spindle 20, in particular into the nut 42. The membrane 18 is now precisely positioned and fixed at the pressure piece 30.

Claims

1. A diaphragm valve (10) with: a lower housing portion (22) having a valve body; an upper housing portion (34) secured at the lower housing portion (22); a diaphragm (18) working with the valve body; an axially adjustable spindle (20) connected to the membrane (18); and a pressure piece (30) which exerts pressure on the membrane (18), characterized in that the spindle (20) and the pressure piece (30) are connected to one another in a non-releasable manner.

2. The diaphragm valve according to claim 1, wherein the spindle (20) and the pressure piece (30) are connected to one another in a material-fit manner.

3. The diaphragm valve according to claim 1, wherein the spindle (20) and the pressure piece (30) are welded or glued to each other.

4. Diaphragm valve according to any of claims 1-3, characterized in that the spindle (20) and the pressure piece (30) are connected to each other by means of laser welding, by means of an ultrasonic welding method, by means of spin welding, by means of a heat-fired or adhesive connection or solvent bonding.

5. The diaphragm valve according to any of claims 1-3, wherein the spindle (20) is provided with a hole at its end facing the pressure piece (30).

6. The diaphragm valve of claim 5, wherein the hole is configured as a blind hole (40).

7. The diaphragm valve of claim 6, wherein the aperture is adapted to receive a nut (42).

8. The diaphragm valve of claim 7, wherein the nut (42) is retained in the bore against loss.

9. The diaphragm valve according to claim 8, wherein the nut (42) is retained in the blind hole (40) in a loss-proof manner.

10. The diaphragm valve according to any of claims 6 to 9, wherein the blind hole (40) has a radial caulking, a radially inwardly projecting nose or an axial groove provided in the inner wall at a distance from its base.

11. The diaphragm valve according to any one of claims 1 to 3, wherein the pressure piece (30) has a hole (36) at its side facing the spindle (20) for receiving a free end of the spindle (20).

12. The diaphragm valve of claim 11, wherein the hole (36) is a blind hole or a stepped hole.

13. The diaphragm valve of claim 12, wherein the base of the blind hole or the stepped hole allows a threaded pin (52) to pass through.

14. The diaphragm valve according to claim 13, wherein the threaded pin (52) engages into a nut (42) comprised in the spindle (20).

15. The diaphragm valve according to claim 13 or 14, wherein the threaded pin (52) has a head (50) and is fixed in the diaphragm (18).

16. The diaphragm valve of claim 15, wherein the head (50) is at an end of the threaded pin (52) surrounded by the diaphragm (18).

17. The diaphragm valve of claim 15, wherein the threaded pin (52) is held in the diaphragm (18) against rotation.