Membranventil

Abstract

Diaphragm valve, comprising a valve body (12) having at least one flow channel for fluid flow, a valve actuator (14) having a housing, and a diaphragm (32) which can be deflected by the valve actuator (14) to selectively open and close the flow channel, wherein the diaphragm (32) is axially clamped fluid-tight at its edge between the valve body (12) and the valve actuator (14), and the clamping of the diaphragm (32) is effected by a screw-nut connection, wherein the screw and the nut (44) surround the diaphragm (32) at its edge as viewed in the actuation direction of the valve actuator (14), and one of the two parts formed by the screw and nut (44) is not rotatably provided on the valve body (12) or on the valve actuator (14), and wherein the other of the two parts is screwable in or screwable on and rotatably movable, characterized in thatthat the moving part is mounted on the valve actuator (14) or on the valve body (12) by means of a rolling bearing and that the moving part of the two parts has an inner diameter that is smaller than the outer diameter of the housing and can only be mounted from the valve body end of the housing.

Description

[0001] The invention relates to a diaphragm valve according to the preamble of claim 1.

[0002] Such a generic diaphragm valve is known from DE 101 53 362 B4. The housing of the valve actuator is fastened to the valve body by a union nut that engages a lateral flange of the valve body and is rotatable relative to it, and that engages an external thread of a sleeve-like extension protruding from the valve body. The generic diaphragm valves to which the present invention relates do not use multiple screws that penetrate flanges on the valve body and the housing in the actuation direction of the valve actuator, but rather a single screw-nut connection that surrounds the diaphragm circumferentially and externally. As can be seen in DE 101 53 362 B4, the union nut is placed on the end of the valve actuator facing away from the valve body and then screwed on.This presses the valve housing against the diaphragm, axially clamping the diaphragm edge between two annular contact surfaces and creating a tight seal. The actuator itself then engages the diaphragm via a tappet to raise or lower it, thereby opening and closing the flow channel. The valve body has a valve seat for this purpose. Typically, in a tubular valve body, this valve seat is designed as at least one shut-off bar that runs perpendicular to the flow channel and, when the diaphragm rests against it, closes the flow channel.

[0003] To ensure secure sealing and retention of the diaphragm, it is important to clamp it with a relatively tight, predetermined contact pressure. Due, among other things, to the dimensions of the threads and the contact surfaces between the union nut and the housing of the valve actuator, a high frictional force occurs. Due to this high resistance, it is relatively difficult to achieve exactly the desired optimal axial clamping force for the diaphragm during assembly or after repair. Furthermore, it is disadvantageous that the union nut always has to be designed as a large fastening part, because it has to be placed over the valve actuator. This also limits the lateral dimensions of the valve actuator, including the housing, connections, etc. The fact that the screw and the nut clamp the diaphragm at its edge in the actuation direction, more precisely in the edge area (i.e.edge), does not mean that the screw and nut must be at the same height as the membrane when viewed from the side, because what matters here is the view in the direction of actuation.

[0004] The use of union nuts is also known from US 2010 / 0 024 904 A1, which deals with a fuel nozzle. Screw-nut connections are also shown in US 2010 / 0 140 528 A1 and US 7 137 578 B2.

[0005] Furthermore, closable filling openings for rolling elements have become known from US 6 820 630 B2.

[0006] DE 35 32 157 A1 shows a tapping device for pressurised steel pipelines.

[0007] DE 602 13 674 T2 shows a metal diaphragm valve with a body, a hood and a hood nut with an internal thread, which is screwed onto the body and presses the hood hermetically against a stepped section of the body.

[0008] The object of the invention is to avoid the above disadvantages.

[0009] In a diaphragm valve of the type mentioned above, this is achieved by having the movable part, namely the screw or nut, mounted on the valve actuator or valve body by a rolling bearing. The non-movable part is then firmly attached to its counterpart, i.e., the valve body or valve actuator.

[0010] The rolling bearing reduces friction between the moving part and the part to which it is mounted—either the valve actuator or the valve body—so that the torque applied when screwing the screw and nut together is almost entirely converted into the required clamping force, and the clamping force can be precisely predetermined. Friction losses are minimal. Thus, the applied torque is significantly lower, and the tool requires a smaller lever arm. This is very advantageous in confined spaces in systems.

[0011] The non-movable part, i.e. either the screw or the nut, i.e. the one of the two parts which is not turned for screwing, can be designed as a separate part or as an integrally formed extension of the valve body or the valve drive, here in particular the housing.

[0012] The housing of the valve actuator does not have to be made of one piece, it is often made of several parts.

[0013] Furthermore, the invention provides that the membrane is preferably clamped axially directly between the valve drive, in particular the housing, and the valve body, without any parts in between.

[0014] The restriction existing in the prior art that the union nut has an inner diameter that is larger than the largest diameter or cross-section of the valve body is eliminated by the invention, because the movable of the two parts has an inner diameter that is smaller than the outer diameter of the housing and can only be mounted from the end of the housing facing the valve body. The movable of the two parts (screw or nut) is therefore pushed onto the valve body or the valve drive, specifically in the area of ​​the connection to the opposite part, which is made possible by the rolling bearing and in particular by the subsequently introduced rolling elements (although not absolutely necessary for this). Preferably, the valve drive is also fastened to the valve body by means of the screw-nut connection, in particular fastened only by this.

[0015] An axial guide can be provided that forms the housing with the valve body, via which the housing is laterally guided to the valve body, preferably with zero play within the positioning tolerances. Before the screw engages the nut, the valve actuator and valve body are aligned and inserted into each other. This also optimizes the correct position of the diaphragm relative to the sealing surfaces on both sides from the outset.

[0016] A circumferential annular extension can protrude from the front of the housing toward the valve body. This annular extension is guided laterally by a protruding, sleeve-like extension provided on the valve body to provide axial guidance. Additionally or alternatively, the annular extension on the front of the housing can clamp the diaphragm edge, i.e., rest directly against it. In one variant, the annular extension thus fulfills a dual function.

[0017] The valve body can be designed with a closed, circular sealing surface for the edge of the diaphragm, against which the diaphragm is pressed. This sealing surface is surrounded by the sleeve-like extension. This also protects the diaphragm from external influences.

[0018] A variant of the invention provides for a thread, particularly an external thread, to be formed on the sleeve-shaped extension, forming the screw. Separate parts attached to the valve body to form the external thread are therefore not required.

[0019] To prevent excessive compression of the diaphragm, an axially acting stop can be provided. A variant of this provides for the sleeve-shaped extension to have an axial stop for the housing, in particular by providing the sleeve-shaped extension with a shoulder against which a shoulder on the annular extension can abut.

[0020] The external thread can be formed on the valve body, around the diaphragm. Therefore, no part attached to the valve body to form the external thread is necessary.

[0021] In particular, the external thread is formed on the sleeve-shaped extension of the valve body.

[0022] The movable part of the two is optionally the nut, which is designed as a union nut. Because the nut is external, this version is easier to grasp with a tool.

[0023] The rolling elements, i.e. the rolling bearing, can be located between the inside of the nut and the housing.

[0024] In general, the rolling bearing can hold and guide the moving part in the lateral and / or axial directions, in particular without the presence of any further plain bearing in these directions between the moving part and its associated part (valve body or valve actuator).

[0025] If the rolling elements are located between the nut and the housing, bearing grooves for the rolling elements can be provided on the nut and the housing to reduce the number of parts. This eliminates the need for separate bearing shells. However, this is not intended to be limiting.

[0026] For mounting the nut or screw, a closable filling opening for rolling elements can be provided in the valve body or housing. This means that the screw or nut, both designed as ring-shaped parts, are pushed onto their corresponding counterpart (valve body or valve actuator). The rolling elements are then inserted through the filling opening, creating a positive connection via the rolling bearing between the screw or nut and the valve body or valve actuator.

[0027] The rolling bearing is in particular a deep groove ball bearing, advantageously an angular contact ball bearing, so that it can absorb radial as well as axial forces.

[0028] The housing and valve body can be circumferentially fixed to each other via a positive-locking anti-twist device, even when the screw-nut connection is not actuated. This means that the housing and valve body are inserted into each other, the anti-twist device is activated, and when the screw and nut are subsequently screwed together, the housing and valve body cannot rotate. This also prevents circumferential movements and shear forces on the diaphragm.

[0029] It should also be emphasized that in this case a bayonet lock can also be regarded as a screw-nut connection.

[0030] The valve actuator itself can be manual, pneumatic, hydraulic or electric.

[0031] The invention also virtually eliminates wear in the area where the valve drive is attached to the valve body.

[0032] Further features and advantages of the invention will become apparent from the following description and the accompanying drawings, to which reference is made. In the drawings: - Fig. 1 a side view through a possible embodiment of the diaphragm valve according to the invention, - Fig. 2 a longitudinal section through the diaphragm valve according to Fig. 1, - Fig. 3 a perspective sectional view through the diaphragm valve according to Fig. 1 in the area of ​​the fastening of the valve body and actuator, - Fig. 4 an enlarged longitudinal sectional view in the area of ​​the attachment of the valve body and valve actuator, - Fig. 5 a greatly enlarged view of the Fig. 4 section marked X, - Fig. 6 a perspective top view of the valve body in the area of ​​its receiving opening for the valve drive and the underside of the valve drive before plugging into one another, and - Fig. 7 a sectional view corresponding Fig. 4 when the valve actuator is placed on the valve body but the screw-nut connection is not yet closed.

[0033] In Fig. 1 shows a diaphragm valve 10 which has a valve body 12, here in the form of a tube, and a valve drive 14 fastened to the valve body 12.

[0034] The valve body in this embodiment is, as mentioned, tubular and has a flow channel in its interior, from which Fig. 1, the outlet 16 can be seen. The flow channel in the valve body 12 can be selectively interrupted or opened by the valve drive 14 to close or open the valve.

[0035] Preferably, and this is not intended to be limiting, the valve body 12 may be a one-piece part that is formed or produced by casting. Suitable materials include metals or plastics.

[0036] In Fig. In Figure 2, in addition to the outlet 16, the inlet 18 of the flow channel can also be seen. A shut-off bar 20 between the inlet 18 and the outlet 16 extends laterally into the flow channel and divides it into two sections. The upper side 22 of the shut-off bar 20 (see Fig. 6) points outwards laterally to the pipe axis, because in this area the valve body 12 is open and has an opening 24 in which the inlet 18 and outlet 16 are fluidly connected to one another when the diaphragm valve 10 is open.

[0037] The valve body 12 has a sleeve-shaped extension 26 formed in one piece, which completely surrounds the opening 24 and is adjacent on the inside to a substantially flat annular sealing surface 28 formed there. The sealing surface 28 merges into the upper side 22 of the shut-off web 20, as Fig. 6 shows.

[0038] An external thread 30 is formed on the radial outer side of the sleeve-shaped extension 26. Thus, the sleeve-shaped extension 26 forms a hollow screw.

[0039] A diaphragm 32 is clamped between the valve drive 14 and the valve body 12 (see Fig. 2). The diaphragm rests on its outer peripheral edge on one side essentially over its entire surface on the sealing surface 28. The diaphragm 32 is axially clamped between its opposite sides and thus sealed by the valve drive 14 pressing against it on the opposite side. For this purpose, the valve drive 14 has a sealing surface 34 opposite the sealing surface 28 (see Fig. 2 and Fig. 7).

[0040] The part of the valve drive 14 provided with the sealing surface 34 is an attachment housing part 36 of the multi-part outer housing of the valve drive 14. The attachment housing part 36 closes off a pot-shaped main housing 38, which accommodates the drive system, towards the valve body 12.

[0041] In the present case, the attachment housing part 36 has a circumferential annular extension 40 projecting from its end face, the outer dimensions of which are matched to the inner dimensions of the sleeve-shaped extension 26, so that the annular extension 40 and the sleeve-shaped extension 26 serve as an axial guide for the valve drive 14 when the valve drive 14 is attached to the valve body 12. The fits between the sleeve-shaped extension 26 and the annular extension 40 are designed such that there is essentially no radial play.

[0042] The sleeve-shaped extension 26 has a radial shoulder, as does the annular extension, which abut and bear against each other in the assembled state of the diaphragm valve 10 to form an axial stop 42.

[0043] The valve drive 14 is fastened to the valve body 12 via a screw-nut connection, which in the present case is realized with a nut 44 mounted on the valve drive 14 and the external thread 30 on the sleeve-shaped extension 26.

[0044] The nut 44, like the external thread 30, completely surrounds the diaphragm 32 in the axial direction A of the valve drive (direction of movement of the valve drive 14). Consequently, only one central screw-nut connection is required.

[0045] In the present case, it is the nut 44, which is rotatably mounted on the valve drive 14 via a rolling bearing with rolling elements 46.

[0046] The bearing is designed as a ball bearing, more precisely as an angular contact ball bearing, as Fig. 5 shows in more detail.

[0047] The rolling elements 46 run in bearing grooves 48, 50 in the nut 44 or in the housing of the valve drive 14.

[0048] The rolling bearing is designed in such a way that it is responsible for the radial as well as the axial support of the nut 44 on the housing. Fig. Figure 5 shows which part of the bearing grooves 48 and 50 bears when the nut 44 is tightened. Corresponding gaps between the bearing grooves 48, 50 and the rolling element 46 indicate where no force transmission takes place.

[0049] A seal 52 between an end face of the nut 44 and the housing provides additional sealing in this area, as does a further ring seal 54 between the outer peripheral surface of the ring extension 40 and the inside of the sleeve-shaped extension 26.

[0050] The nut 44 has a smallest inner diameter which is significantly smaller than the outer diameter of the housing, so that the nuts cannot be pushed from above, relative to Fig. 2, must be placed and mounted over the housing, as is the case in the state of the art and therefore does not protrude extremely laterally beyond the outer housing.

[0051] In the illustrated embodiment, the nut 44 is already attached to the valve drive 14 and does not need to be handled as a loose part. Rather, the nut 44 is placed on the annular extension 40, onto which the nut is pushed. In this state, the rolling elements 46 are not yet present. The rolling elements 46 are inserted from the inside of the housing via a removable plug 56 (see Fig. 2) is inserted from the inside to fill the annular space between the bearing grooves 48, 50.

[0052] In particular, and this is not to be understood as limiting, this annular space is circumferentially filled to at least 50% with rolling elements, in particular to at least 90% with rolling elements (see Fig. 3). The filling opening has the reference number 58, see Fig. 4.

[0053] The diaphragm valve is installed as described in the Fig. 6 and Fig. 7. First, the valve actuator 14 is inserted into the sleeve-shaped extension 26 with the ring extension 40 facing forward. The two parts are mounted laterally relative to each other.

[0054] A positive locking device against rotation, in this case by at least one axially projecting bead 60 and a complementary recess 62 on the ring extension 40 or on the inside of the sleeve-shaped extension 26, see Fig. 6, ensures that the valve drive 14 is aligned and fixed in the circumferential direction to the valve body 12.

[0055] This anti-twist device also ensures that the valve body and / or housing are not rotated when the nut 44 is tightened.

[0056] Fig. 7 shows the nut 44 when it engages the first thread of the external thread 30.

[0057] Then the nut 44, which has recesses 70 on its outside for better torque absorption, is screwed further onto the external thread 30. During this movement, the nut 44 pulls the valve drive 14 axially against the valve body 12 via the roller bearing. The sealing surface 34 rests on the diaphragm 32 and also presses it downwards until it touches the sealing surface 28 (see Fig. 7) and presses against it. This axial displacement continues until the stop 42 is effective. At this point, the nut 44 also presses against an annular seal 72 located on the sleeve-shaped extension and at the end of the external thread 30, which additionally counteracts loosening of the nut 44. The annular seal 72 also prevents dirt from penetrating the threads and the rolling bearing.

[0058] Of the two parts, screw and nut 44, the nut is movable in this case and is positively and rotatably attached to the valve actuator 14 via a rolling bearing. However, the nut 44 could also be rotatably and positively attached to the valve body via a rolling bearing; in this case, the valve actuator 14 would have an external thread to form the screw.

[0059] Conversely, it does not necessarily have to be the nut 44 that is mounted on the valve body 12 or the valve drive 14 via a rolling bearing. It could also be the screw with the external thread, designed as a rotatable sleeve, which is mounted on either the valve body 12 or the valve drive 14 via a rolling bearing. In this case, the internal thread, i.e., the nut, would preferably be an integral part of the corresponding other part, i.e., the valve drive 14 or the valve body 12, and would be non-rotatably attached to this part.

[0060] The diaphragm 32 is moved axially via a valve stem 74, as is usual with a diaphragm valve, in order to either, as in Fig. 2, to close the diaphragm valve by pressing on the upper side 22 of the shut-off bar 20, or by being spaced from it. The valve stem 74 is secured to the valve body 72 by a suitable fastening device 76 (see Fig.4) preferably positively coupled to the diaphragm 32 in order to transmit the axial movement of the valve stem 74 to the diaphragm 32. At the opposite end of the valve stem 74, the drive mechanism is provided, which according to the exemplary embodiment is designed as a pneumatic drive with several springs that ensure that the valve is acted upon in the closing direction. However, this is not to be understood as limiting. An electric drive can just as well be present in the housing, or the valve stem 74 can protrude upward through the housing so that it can be operated manually. The space 101 above the diaphragm 32 is ventilated via a leakage bore 100, which leads through the annular extension 40 and the sleeve-shaped extension 26. This is necessary in order to detect leaking diaphragms 32.

Claims

[1] Diaphragm valve, comprising a valve body (12) having at least one flow channel for fluid flow, a valve drive (14) having a housing, and a diaphragm (32) which can be deflected by the valve drive (14) in order to selectively open and close the flow channel, wherein the diaphragm (32) is axially clamped at the edge between the valve body (12) and the valve drive (14) in a fluid-tight manner, and the clamping of the diaphragm (32) is effected by a screw-nut connection, wherein the screw and the nut (44) surround the diaphragm (32) at the edge as seen in the actuation direction of the valve drive (14), and one of the two parts formed by the screw and nut (44) is provided non-rotatably on the valve body (12) or on the valve drive (14), and wherein the other of the two parts can be screwed in or unscrewed and is rotatably movable, characterized bythat the movable part is mounted by a rolling bearing on the valve drive (14) or on the valve body (12) and that the movable of the two parts has an inner diameter which is smaller than the outer diameter of the housing and can only be mounted from the valve body-side end of the housing. [2] Diaphragm valve according to claim 1, characterized by that the valve drive (14) is fastened to the valve body (12) by means of the screw-nut connection, in particular only by means of the screw-nut connection. [3] Diaphragm valve according to claim 1 or 2, characterized by that the housing forms an axial guide with the valve body (12), via which the housing is guided laterally to the valve body (12). [4] Diaphragm valve according to claim 3, characterized bythat a circumferential annular extension (40) protrudes from the front side of the housing, which is guided laterally on a protruding sleeve-shaped extension (26) provided on the valve body (12), whereby the axial guide is formed, and / or that the annular extension (40) clamps the diaphragm edge. [5] Diaphragm valve according to claim 4, characterized by that the valve body (12) has an annularly closed circumferential sealing surface (28) for the edge of the membrane (32), against which the membrane (32) is pressed, and in particular that this sealing surface (28) is surrounded by the sleeve-shaped extension (26). [6] Diaphragm valve according to claim 4 or 5, characterized by that a thread, in particular the external thread, is formed on the sleeve-shaped extension (26) to form the screw. [7] Diaphragm valve according to one of claims 4 to 6, characterized bythat the sleeve-shaped extension (26) has an axial stop for the housing, which in particular abuts against a shoulder on the annular extension (40). [8] Diaphragm valve according to one of the preceding claims, characterized by that the external thread (30) is formed on the valve body (12) around the membrane (32). [9] Diaphragm valve according to one of claims 4 to 7 and additionally according to claim 8, characterized by that the external thread (30) is formed on the sleeve-shaped extension (26). [10] Diaphragm valve according to one of the preceding claims, characterized by that the nut (44) is the movable part of the two parts formed by the nut (44) and the screw and is designed as a union nut. [11] Diaphragm valve according to one of the preceding claims, characterized bythat rolling elements (46) are located between the inside of the nut (44) and the housing, and in particular that bearing grooves for the rolling elements (46) are formed on the nut (44) and the housing. [12] Diaphragm valve according to one of the preceding claims, characterized by that a closable filling opening (58) for rolling elements (46) is provided in the valve body (12) or in the housing. [13] Diaphragm valve according to one of the preceding claims, characterized by that the rolling bearing is an angular contact ball bearing. [14] Diaphragm valve according to one of the preceding claims, characterized by that the housing and valve body (12) are circumferentially firmly positioned relative to one another via a positive rotation lock even when the screw-nut connection is not closed.

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