Quetschventil

Abstract

Pinch valve with a dimensionally stable valve housing (3) penetrated by a working recess (12) extending along an axis of extension (2), and with a valve hose (15) received in the working recess (12), made of a rubber-elastic material and penetrated by a fluid channel (48), extending between an inlet port (8) and an outlet port (9) of the working recess (12) and defining a fluid-tight, pressurizable, and variable-size working chamber together with the working recess (12), which is designed for pressure-dependent adjustment of a cross-section (45, 46, 47) of the fluid channel (48) between an open position and a closed position, wherein the valve hose (15) in a neutral position has at least a sectionwise oval cross-section (45, 46) in a cross-sectional plane (52) oriented transversely to the axis of extension (2), characterized in thatthat the fluid channel (48) has constant cross-sectional areas along the axis of extension (2) in the neutral position, wherein the valve hose (15) has a mounting flange (42, 43) extending section by section along the axis of extension (2) and extending from the inlet port (8) and from the outlet port (9), and wherein the valve hose (15) has a deformation section (51) between the two mounting flanges (42, 43), the outer surface of which forms a step (60, 61) at its end with an outer surface of the respective adjacent mounting flange (42, 43), and wherein the valve hose (15) has elliptical cross-sections at least section by section in cross-sectional planes (52) oriented transversely to the axis of extension (2), wherein the elliptical cross-sections in the cross-sectional plane (52) are each defined by a principal axis (45) and a minor axis (46) be determinedwherein for at least one elliptical cross-section an extreme value for a length ratio of the secondary axis (46) relative to the main axis (45) in the neutral position of the valve hose lies in an interval of 0.4 to 0.8.

Description

[0001] The invention relates to a pinch valve with a dimensionally stable valve housing which is penetrated by a working recess which extends along an extension axis, and with a valve hose which is received in the working recess, is made of a rubber-elastic material and has a fluid channel through it, which extends between an inlet connection and an outlet connection of the working recess and which, together with the working recess, delimits a fluid-tight, pressurizable and size-variable working space which is designed for the pressure-dependent adjustment of a cross-section of the fluid channel between an open position and a closed position, wherein the valve hose, in a neutral position, in particular in the open position, has at least in sections an oval cross-section in a cross-sectional plane oriented transversely to the extension axis.

[0002] From EP 2 047 151 A1 a pinch valve is known in the valve housing of which a cartridge-like structural unit is detachably inserted, which has a tubular valve member and a support tube arranged around it, wherein the support tube consists of several shell elements arranged one after the other in the circumferential direction of the valve member and are attached to the outside of the valve member in the radial direction.

[0003] WO 2018 / 007 990 A1 discloses a sleeve valve with a hollow cylindrical base body provided on the inside with a longitudinal axial opening that defines a substantially elliptical profile in a transverse plane by the union of two circumferential arcs, wherein the central section of each of the circumferential arcs has a substantially radial rib. At least one constriction region is formed on the base body by the arrangement of two tapered segments.

[0004] From US 1 683 322 A a valve of simplified construction is known which is designed to avoid contact of the liquid contained with metal parts when opening and closing the valve. For this purpose, the valve is provided with a rubber lining, which may have a simple shape, which extends over the entire extent of both the fixed and the moving parts of the valve.

[0005] DE 10 2004 043 922 A1 discloses a pinch valve with a hose cuff with vulcanized or glued-on end connection parts, wherein a housing is pushed onto this structural unit and firmly connected to the two connection parts 1.

[0006] From EP 0 690 254 B1, it is known to insert a sleeve into the passage of a valve housing. This sleeve is attached to the valve housing via a bayonet joint on the one hand and a support assembly on the other. A fastening sleeve embedded in the sleeve body has protruding tabs that can be moved through grooves during assembly of the sleeve into the valve housing. The retaining sleeve has a collar that comes into contact with the support surface of the valve housing when the sleeve is inserted. When the sleeve is subsequently rotated, the tabs engage behind the retaining surface of the valve housing.

[0007] The object of the invention is to provide a pinch valve with improved service life.

[0008] This object is achieved for a pinch valve of the type mentioned above with the features of claim 1. It is provided that the fluid channel in the neutral position, in particular in the open position, has constant cross-sectional areas along the extension axis.

[0009] When the fluid channel is subdivided into individual fluid channel sections with a length approaching zero (infinitesimal), each fluid channel section has an associated cross-section whose surface area is at least nearly identical to the surface areas of all other cross-sections of the fluid channel sections of the valve tube. This design of the valve tube prevents the pinch valve from causing a wear-promoting throttling effect on a fluid flow through the fluid channel even in a neutral position, which the valve tube assumes, especially in an unused, new state, without the influence of external forces, especially in the open position, which can be considered the preferred neutral position.Rather, the fluid flow can flow through the fluid channel with minimal fluid friction, which is determined solely by an interaction of the flowing fluid with the inner surface of the fluid channel, but not by throttling effects such as those that occur in the pinch valve known from the prior art due to the change in the cross-sectional areas provided there.

[0010] Accordingly, the valve tube is subject to significantly less wear, at least in the neutral position, especially in the open position, than is the case with a conventional pinch valve. Even if the free cross-section of the fluid channel is reduced by pressurizing the working recess and the resulting compression of the valve tube, which is accompanied by an increase in the working space, less throttling occurs within the fluid channel than is the case with the conventional pinch valve.

[0011] It is preferably provided that the fluid channel in the closed position along the extension axis has at least in sections a vanishing cross-section, so that a fluid flow through the valve hose can be at least almost completely prevented.

[0012] The improvement in the service life of the valve hose due to the design with a constant cross-sectional area along the extension axis is particularly interesting when the fluid flow flowing through the fluid channel contains, for example, solid particles, especially abrasive solid particles. As an example, a pinch valve is used to influence the fluid flow of a mass flow of solid particles, such as grain or sand, fluidized with compressed air or a liquid such as water.

[0013] Advantageous further developments of the invention are the subject of the subclaims.

[0014] It is expedient for the valve hose to be adapted to the working recess in such a way that it is at least almost, and in particular completely, free of stress in the neutral position, in particular in the open position. This measure also contributes to improving the service life of the valve hose and the pinch valve equipped with it, since in practice it can be assumed that the valve hose normally assumes the open position and that at least almost no, and in particular no, stress is present in the valve hose. The stresses occurring in the valve hose include, on the one hand, radial stresses, which should be regarded as internal stresses in the valve hose whose force directions are aligned in cross-sectional planes transverse to the extension axis.Furthermore, it can be provided that the valve hose is installed in the working recess of the valve housing with an axial preload during assembly to ensure a defined opening position, which is also attributable to the stresses in the valve hose. Depending on the geometric design of the valve hose, these axial stresses can also result in radial stress components, which, however, are considerably smaller than the radial stress components that occur in the respective cross-sectional planes when the valve hose is transferred from the open position to the closed position.

[0015] Preferably, the valve hose has a circular cross-section in the region of the inlet connection and / or in the region of the outlet connection in a cross-sectional plane oriented transversely to the axis of extension. This ensures advantageous adaptation of an inlet cross-section and / or an outlet cross-section of the valve hose to an upstream or downstream fluid line, which is in particular circular sleeve-shaped. Furthermore, it can be provided that a continuous cross-sectional change is provided for the fluid channel between the circular inlet cross-section and the at least partially oval cross-section, which is present in particular in a central region of the valve hose. This continuous cross-sectional change can prevent undesirable and wear-promoting turbulence in the fluid flowing through the pinch valve.

[0016] In an advantageous development of the invention, it is provided that the valve hose, starting from the inlet connection and starting from the outlet connection, each has a circular fastening flange extending in sections along the extension axis. Between the two fastening flanges, the valve hose has a deformation section which, at its end, forms a stepped shoulder with the adjacent fastening flanges, the outer surface of which forms a step with an outer surface of the adjacent fastening flange. The fastening flanges formed at each end of the valve hose serve to secure the valve hose in the working recess of the valve housing in a force-fitting and / or form-fitting manner.For this purpose, the mounting flanges, unlike the deformation section, are designed in such a way that they do not experience any significant elastic or plastic deformation during intended use of the pinch valve. Rather, the mounting flanges serve exclusively to transmit force between the valve hose and the valve housing, in particular to transmit axial forces from the valve hose to the valve housing. The task of the deformation section, on the other hand, is to ensure a purely elastic deformation of this area of ​​the valve hose, depending on the pressure ratio that exists between the fluid channel and the working chamber. This deformation can be used to achieve the desired adjustment of the free cross-section of the fluid channel between the open and closed positions.

[0017] In order to ensure an advantageous force flow and an advantageous deformation capacity for the deformation section, it is provided that a step is formed at a transition area between the deformation section and the respective fastening flange, with the aid of which the desired permanent coupling between the elastically deformable deformation section and the fastening flange, which is dimensionally stable within the scope of the intended use, can be achieved over a short distance along the extension axis.The step is realized in particular in the form of an outer diameter jump, which can be shown, for example, by means of a first circular envelope around the fastening flange in a cross-sectional plane oriented transversely to the extension axis and a second circular envelope around the deformation section in a cross-sectional plane oriented transversely to the extension axis, wherein the first envelope has a significantly larger diameter than the second envelope.

[0018] In an advantageous development of the invention, the valve tube, in the neutral position, particularly in the open position, has, at least in sections, elliptical cross-sections in cross-sectional planes oriented transversely to the extension axis. This ensures a favorable distribution of radial stresses within the valve tube for each deformation state between the open and closed positions of the valve tube.

[0019] This applies in particular when the elliptical cross sections in the respective cross-sectional plane are each determined by a main axis and a secondary axis, wherein for at least one elliptical cross section an extreme value for a length ratio of the secondary axis relative to the main axis in the neutral position, in particular in the open position, of the valve tube lies in an interval of 0.4 to 0.8.

[0020] It is preferably provided that the deformation section in a first cross-sectional plane, which includes the extension axis and the main axis, adjacent to the fastening flange has a wall thickness which is 2 times, preferably 3 times, in particular 3.5 times a wall thickness of a central section of the deformation section in the first cross-sectional plane and / or that the deformation section in a second cross-sectional plane, which includes the extension axis and the minor axis, adjacent to the fastening flange has a wall thickness which is 3 times, preferably 4 times, in particular 5 times a wall thickness of a central section of the deformation section in the second cross-sectional plane.

[0021] These measures ensure that deformation of the deformation section occurs primarily in a central section of the valve hose, while in those sections located closer to the mounting flanges, deformation occurs, particularly gradually. This prevents sudden changes in the internal stresses occurring during the deformation of the deformation section within the valve hose, thus preventing undesirable stress concentrations that would otherwise lead to increased susceptibility to wear of the valve hose.

[0022] It is expedient for the valve housing to have a circular cross-section in each cross-sectional plane oriented transversely to the extension axis. The valve housing is preferably designed as a circular-cylindrical sleeve, which can, for example, be provided at each end with a screw ring whose external thread engages an internal thread in the working recess and can be used to axially secure the valve tube.

[0023] In an advantageous development of the invention, at least one spacer arranged between an inner surface of the valve housing and an outer surface of the valve tube is assigned to the working recess, which spacer rests flatly in certain areas against the inner surface of the valve housing and against the outer surface of the valve tube in order to ensure support of the valve tube in the open position. For example, the spacer is made of two half-shells that surround the valve tube in sections and only partially fill the working space, for example in the manner of a lattice structure, in order not to impair the pressure effect of a pressurized fluid, which is introduced into the working space to influence the free cross-section of the fluid channel, on the outer surface of the valve tube.Preferably, the spacer serves to axially support the valve hose so that it always remains reliably contained in the valve housing, regardless of its open or closed state. Additionally, the spacer serves to transmit force between the valve hose and the valve housing in the event that a pressurized fluid flows in the fluid channel and there is no corresponding counterpressure in the working chamber due to pressurization of the working recess. In such a case, the spacer is intended to prevent undesirable radial expansion of the deformation section of the valve hose, which could lead to damage to the valve hose.

[0024] In an alternative development of the invention, the valve housing has oval cross-sections at least in some regions in cross-sectional planes oriented transversely to the extension axis. Preferably, the valve housing is designed such that an inner surface of the working recess partially abuts an outer surface of the valve tube, without impairing the inflow or outflow of pressurized fluid, in particular compressed air, into or out of the working chamber, or the pressure effect of this working fluid on the valve tube.

[0025] An advantageous embodiment of the invention is illustrated in the drawing. Fig. 1 a perspective overview of a pinch valve with a circular cylindrical valve housing, which is provided at each end with screw rings which serve to secure a valve hose and which comprises a fluid connection on an outer surface for providing a control fluid flow, Fig. 2 an exploded view of the pinch valve according to the Fig. 1, Fig. 3 an exploded view of the valve hose with separately shown support rings designed to be accommodated in the valve hose and designed to be dimensionally stable, Fig. 4 a front view of the pinch valve according to the Fig. 1, Fig. 5 a sectional view of the pinch valve in a first cross-sectional plane starting from the representation of the Fig. 4, Fig. 6 one opposite the Fig. 4 Side view of the pinch valve rotated by 90 degrees and cut, and Fig. 7 a sectional view of the pinch valve in a second cross-sectional plane starting from the representation of the Fig. 6.

[0026] One in the Fig. The pinch valve 1 shown in perspective in FIG. 1 is designed to influence a fluid flow (not shown in detail) that can flow through the pinch valve 1 along an extension axis 2. The fluid flow can be, in particular, a liquid, a gas, fluidized solid particles, or mixtures thereof.

[0027] For example, the pinch valve 1 can be used for dosing a free-flowing substrate such as sand or grain. For example, the pinch valve 1 is mounted at the lower end of a storage container filled with the substrate in order to selectively enable or prevent a targeted downward flow of the substrate in a vertical direction.

[0028] By way of example, the pinch valve 1 comprises a tubular valve housing 3 with a circular cross-section, which is provided at each end with a first screw ring 4 and a second screw ring 5. Each of the two screw rings 4 and 5 is, as shown in the Fig. 2 each penetrated by a circular cylindrical recess 6 or 7, which defines an inlet cross-section 8 serving as an inlet connection and an outlet cross-section 9 serving as an outlet connection for the pinch valve 1. Preferably, the screw rings 4 and 5 are each designed identically, so that the inlet cross-section 8 and the outlet cross-section 9 are also identical to one another.

[0029] A fluid coupling 11 is attached to an outer surface 10 of the valve housing 3 and is designed to supply and discharge a pressurized fluid into and from a working recess 12 of the valve housing 3.

[0030] As the representation of the Fig. 2 can also be removed, in the working recess 12 of the valve housing 3, in addition to a valve hose 15, two spacer parts 16, 17, each designed as half-shells, are arranged, each having an at least substantially closed inner wall 18, 19 and a lattice structure 20, 21 projecting at least substantially radially outwards from the inner wall 18, 19. The individual struts of the lattice structures 20, 21, not designated in more detail, are designed such that they partially bear against an inner surface 22 of the working recess 12 with their radially outwardly lying end faces. Furthermore, it is provided that areas between the inner surface 23 and the respective lattice structures 20, 21 are always exposed, through which a pressurized fluid, which is provided into the working recess 12 via the fluid coupling 11, can flow into all areas of the lattice structures 20, 21.

[0031] The inner walls 18, 19 of the spacer parts 16, 17 are each provided with supply bores 23, through which an inflow and outflow of the pressurized fluid can be ensured in a space not shown in detail between the respective spacer part 16 or 17 and an outer surface 24 of the valve hose 15.

[0032] By way of example, it is provided that the spacer parts 16, 17 each have externally arranged and mutually corresponding locking means 25, 26, which are designed for reliable positioning of the spacer parts 16 and 17 relative to one another. Furthermore, adjacent to the respective locking means 25, 26 on the spacer parts 16 and 17, guide profiles 27 extending in the axial direction are formed, which are intended to be received in profile recesses 28 of the valve tube 15. This ensures a positive coupling between the respective spacer part 16 or 17 and the valve tube 15, at least in the axial direction along the extension axis 2.In this case, it can be provided in particular that an axial extension 29 of the spacer parts 16 and 17 is selected to be slightly greater than a distance 30 between oppositely arranged end faces of the profile recess 28, so that when the spacer parts 16, 17 are mounted on the valve hose 15, a slight elastic deformation of the valve hose 15 is already caused in the axial direction along the extension axis 2.

[0033] The valve hose 15, together with the spacer parts 16 and 17 mounted thereon, can be inserted into the working recess 12 of the valve housing 3 and then secured in the valve housing by screwing in the two screw rings 4, 5. For this purpose, the two screw rings 4, 5 can each be screwed into a corresponding internal thread 34 of the valve housing 3 with an external thread 32, 33. Preferably, the screw rings 4, 5 rest flatly against circular end faces 38, 39 of the valve hose 15 with their mutually facing end faces 34, 35 in order to ensure a sealing effect between the respective screw rings 4, 5 and the valve hose 15.In order to ensure a radial sealing effect between the two fastening flanges 42, 43 and the valve housing 3, it is provided purely by way of example that each of the fastening flanges 42, 43 is provided with an integrally formed, circumferential annular collar 53, 54, which ensures the sealing contact of the valve hose 15 on the valve housing 3 in the manner of a sealing ring.

[0034] Purely exemplary, according to the representations of the Fig. 3 to 7, it is provided that dimensionally stable support rings 40 and 41, respectively, made in particular of a metal material, are incorporated into the valve hose 15 in the axial direction inwardly at a short distance behind the respective end faces 38, 39, which are intended to ensure stabilization of the valve hose 15 against both axial forces and radial forces. The support rings 40 and 41 are each received in circular-cylindrical mounting flanges 42, 43 of the valve hose 15. By way of example, it is provided that the support rings 40 and 41 are incorporated in a combined injection molding and vulcanization process.

[0035] As the representations of the Fig. 4 to 7, the valve tube 15 has a circular cross-section in the region of the end faces 38, 39, while the valve tube 15 is formed with an elliptical cross-section in a central region 44, in particular in a centrally arranged cross-sectional plane 52. A major axis 45 of the elliptical cross-section has, purely by way of example, a length that is approximately 1.8 times the length of a minor axis 46.

[0036] Furthermore, it is provided that a diameter 47 of the valve hose 15 in the region of the end faces 38 and 39 is selected such that a cross section for a fluid channel 48 determined by the valve hose 15 along the extension axis 2 is at least substantially constant.

[0037] As can be seen from the representations of the Fig. 5 and Fig. 7, the fluid channel 48 in the open position has both in a first cross-sectional plane 49, which includes the extension axis 2 and the main axis 45 (wherein the associated cross-section in the Fig. 5), as well as in a second cross-sectional plane 50, which includes the extension axis 2 and the minor axis 46 (wherein the associated cross-section is shown in the Fig. 7) exhibit a continuous cross-sectional change. Due to the absence of cross-sectional jumps, turbulence in a fluid flowing through the fluid channel 48 is largely avoided, thus ensuring minimal wear on the valve hose 15.

[0038] As can be seen from the presentation of the Fig. 3, a geometrically offset deformation section 51 extends between the two fastening flanges 42 and 43, which, according to the illustrations of the Fig. 5 and Fig.7 in the central region 44 in the respective cross-sectional planes 49 and 50 has a minimum wall thickness 55 and 56, respectively, while the deformation section 51 adjacent to the respective fastening flanges 42 and 43 in the cross-sectional planes 49 and 50 has maximum wall thicknesses 57 and 58, respectively.

[0039] By way of example, it is provided that the deformation section 51 with the axially adjacent fastening flanges 42 and 43 each forms a concave or convex step geometry 60, 61 which is rounded to avoid internal stress peaks in order to ensure a transition from the dimensionally stable fastening flange 42 or 43 to the deformation section 51 which is elastically deformable during normal use on a relatively short section of the extension axis 2.

Claims

[1] Pinch valve with a dimensionally stable valve housing (3) through which a working recess (12) extends, which extends along an extension axis (2), and with a valve hose (15) received in the working recess (12), made of a rubber-elastic material and through which a fluid channel (48) passes, which extends between an inlet connection (8) and an outlet connection (9) of the working recess (12) and which, together with the working recess (12), delimits a fluid-tight, pressurizable and size-variable working space, which is designed for the pressure-dependent adjustment of a cross-section (45, 46, 47) of the fluid channel (48) between an open position and a closed position, wherein the valve hose (15) in a neutral position has at least in sections an oval cross-section (45, 46) in a cross-sectional plane (52) oriented transversely to the extension axis (2), characterized bythat the fluid channel (48) in the neutral position has constant cross-sectional areas along the extension axis (2), wherein the valve hose (15) starting from the inlet connection (8) and starting from the outlet connection (9) each has a fastening flange (42, 43) which extends in sections along the extension axis (2) and is of an annular shape, and wherein the valve hose (15) between the two fastening flanges (42, 43) has a deformation section (51), the outer surface of which forms a step (60, 61) at the end with an outer surface of the respectively adjacent fastening flange (42, 43), and wherein the valve hose (15) in the neutral position has, at least in sections, in each case elliptical cross-sections in cross-sectional planes (52) aligned transversely to the extension axis (2), wherein the elliptical cross-sections in the cross-sectional plane (52) each derive from a main axis (45) and a minor axis (46),wherein for at least one elliptical cross-section, an extreme value for a length ratio of the minor axis (46) relative to the major axis (45) in the neutral position of the valve tube lies in an interval of 0.4 to 0.8., [2] Pinch valve according to claim 1, characterized by that the valve hose (15) is free of tension in the neutral position. [3] Pinch valve according to claim 1 or 2, characterized by that the valve hose (15) has a circular cross-section in the region of the inlet connection (8) and / or in the region of the outlet connection (9) in a cross-sectional plane oriented transversely to the extension axis (2). [4] Pinch valve according to claim 1, characterized byin that the deformation section (51) has, in a first cross-sectional plane (49) comprising the extension axis (2) and the main axis (45), adjacent to the fastening flange (42, 43), a wall thickness (57) which is twice a wall thickness (55) of a central section (44) of the deformation section (51) in the first cross-sectional plane (49) and / or in that the deformation section (51) has, in a second cross-sectional plane (50) comprising the extension axis (2) and the minor axis (46), adjacent to the fastening flange (42, 43), a wall thickness (58) which is three times a wall thickness (56) of a central section (44) of the deformation section (51) in the second cross-sectional plane (50). [5] Pinch valve according to one of the preceding claims, characterized by that the valve housing (3) has a circular cross-section in cross-sectional planes aligned transversely to the extension axis (2). [6] Pinch valve according to claim 5, characterized by that the working recess (12) is assigned at least one spacer (16, 17) arranged between an inner surface (22) of the valve housing (3) and an outer surface (24) of the valve hose (15), which spacer rests in regions flat against the inner surface (22) of the valve housing (3) and against the outer surface (24) of the valve hose (15) in order to ensure support of the valve hose (15) in the neutral position. [7] Pinch valve according to one of claims 1 to 6, characterized by that the valve housing (3) has at least partially oval cross-sections in cross-sectional planes aligned transversely to the extension axis (2).

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