FR2512514A1 - NON-RETURN VALVE - Google Patents

Abstract

The invention relates to a non-return valve comprising a body 10 which forms a flow channel 98 exhibiting a shrinkage 12, a mobile valve 16 solicited by a spring 29, and a star support 23 disposed in the body inside OF THE FLOW CHANNEL 98, THE SPRING 29 BEARING ON THE STAR SUPPORT 23. THE WALL OF THE BODY 10 IS MONOBLOC. THE STAR SUPPORT 23 IS FIXED BY A SNAPPING ASSEMBLY 15, 28 AT THE DOWNSTREAM END OF THE BODY 10, ITS REAR FRONT FACE BEING FREE.

Description

NON-RETURN VALVE

  The subject of the invention is a non-return valve

  comprising a body which forms a flow channel present

  both a narrowing, a valve axially movable in said body, biased by a spring against the narrowing-

  mentioned above with which it then forms a watertight filling

  che, finally a star support mounted on said body, which extends inside said flow channel and on which said spring rests, the wall of the valve body being in one piece and having no separation in the direction axial. Such non-return valves are used in the pipelines conveying liquids in order to ensure that the fluid can circulate in the pipeline only in one direction, the opposite direction being closed. Thus, for example, there are non-return valves on the

  water meters or other points in a supply network

  tion of water, to prevent polluted or non-potable water

  to flow back to drinking water pipes.

  Known non-return valves include a spring which urges a valve, against the passage of the

  fluid, towards a shoulder of narrowing of the drainage channel

  Lement This spring is supported inside the body by an annular shoulder (British patent 954 908) To achieve mounting the valve and the spring inside the valve body, the latter is in two parts Both valve body halves, which are one against

  the other in the longitudinal direction, are assembled by screw-

  wise Now, the corresponding thread constitutes a path of

  leakage of the contained liquid, which requires sealing

  additional tee closing this path, otherwise the valve

  pe would no longer be waterproof due to the existence of

  leakage rants, the liquid then being able to flow back in the prohibited direction The use of a valve body in several parts assembled by screwing and of additional sealing members involves a high cost price Another disadvantage resides in that, both

  parts of a body being screwed one on the other, the tension

  initial tension of the spring which acts on the piston varies according to the degree of tightening of the screwed assembly Thus, the stop characteristic of the non-return valve varies according to the tightening by screwing of the two parts of the body

valve.

  In another known check valve, (U.S. Patent 3,346,009), the valve body

  has the shape of a double trunk of cne, the spring being sup-

  carried by one of the cones and urging the valve towards the other rod Here again, the body consists of two parts arranged one against the other and assembled by screwing or welding In the case where the two parts are axially assembled to each other by screwing, the aforementioned drawbacks occur In the case of welding, the apparatus

  thus constituted no longer allows any subsequent intervention

  re in the valve body In addition, the support of a spring

  on a conical wall is uncertain and subject to failure

  these. Finally, a non-return valve is known (German patent application DEAS No. 10 44 537), the body of which consists of two parts assembled by axial screwing. Between the two parts of the body is clamped a star support, said support comprising a valve guide member In addition, the support supports the spring intended to stress

  the valve to its closed position Such a construction

  tion presents, as a result of its two-part design, the disadvantages already mentioned with regard to leaks

  or tightness The opening pressure of the anti-

  back depends to a large extent on the degree of tightness of

  the screw connection between the two parts of the body.

  We finally know a check valve with body

  monobloc in which a star support is screwed immediately-

  downstream of the narrowing A sealing ring

  is arranged between the support and the valve body.

  The object of the invention is to create a check valve.

  return of the type indicated above, consisting of a small number of parts easy to manufacture and having a

  low hydrodynamic resistance on passage of the fluid.

  To solve this problem, it is provided, according to the invention, to fix the star support at the downstream end of the valve body by means of a snap, its

  rear face remaining free.

  Thanks to the use of a monobloc body, the side wall of the body is closed over its entire length, which makes it impossible to leak along this wall The star support is at the downstream end (relative to the direction liquid flow) from the valve body; there is

  is fixed after the installation of the valve and its spring.

  When the device is mounted in a trans-

  carrying liquids, the body is normally fixed axially at the end of a tube The transition between said tube and the

  valve is sealed using a compression washer

  ble, which prevents any flow of liquid along the valve body As for the assembly between the star support and the enveloping wall of the body, it requires no sealing member In the closed position of the device, in assuming that the valve does not allow any parcel of liquid to pass, there can be no leaks, since the body has an axially continuous wall,

without any screwed part.

  According to an advantageous embodiment of the inventio 4, a circular shoulder is provided at the downstream end of the valve body, the star support having a peripheral ring whose internal face is substantially in the extension of the internal wall of the body This peripheral ring fills the part of the body located downstream of the shoulder, so that, in this zone, the interior wall of said ring forms the extension of the wall which defines the flow channel. Thus, the peripheral ring does not hardly disturbs the liquid flow conditions The peripheral ring does not, moreover, require any sealing member with respect to the internal face

of the body wall.

  To obtain a solid and well-defined foundation

  star support inside the body, the ring

  rique cooperates with the enlarged part of the wall of the body by a snap connection, formed by a groove and a bulge The axial position of the star support, on which the valve spring is supported, is thus

  precisely fixed, which makes it possible to determine exact-

  the pressure exerted by the valve against the constriction

  ment of the body, without the spring force being able to vary later.

  The valve according to the invention can be made

  easily born with a small number of parts, which are mainly made of plastic According to a preferred embodiment, the valve body has a wall of substantially constant thickness at all its points; he has a form

  presenting a symmetry of revolution and its cross section

  axial axial varies according to a hydrodynamic Laval curve Since the said body is in one piece, there are no connecting edges in the flow channel and

  the device can therefore present, in the direction of flow-

  very low hydrodynamic resistance.

  The invention is explained below in more detail using an example execution without character

  limiting, shown in the accompanying drawing.

  In this drawing: FIG. 1 is a view in axial section of a

  non-return valve according to the invention mounted in a pipe

  Figure 2 is a view of said valve

  along arrow II of Figure 1.

  The non-return valve comprises a body 10 with symmetry of revolution which forms, at its upstream end, a flange 11 whose inner edge is connected, by a constriction 12, to a cylindrical section 13 A

  the downstream end of the body 10 is a zone of enlargement

  annular ring 14 preceded by a shoulder On the face

  inside this zone 14 is an annular groove 15.

  The valve 16 of the valve carries a plate 17,

  which can slide axially inside the flow channel

  Lement 98 On its rear face, this plate 17 carries a

  sealing washer 18 which slightly exceeds it in diameter

  meter and which is clamped against the rear face of the plate

  sheet 17 by a support disc 19 The latter is fixed on a rod 20 which extends downstream along the axis

body 10.

  The rear face of the valve 16 is biased by a helical spring 29 which coaxially surrounds the rod 20 The latter enters an annular housing 22 of the star support 23, where it is guided and in which it bears axially The inner wall 24 of the annular housing 22 surrounds an orifice intended for the passage of the rod 20, while the outer wall 25 has a

  frustoconical shape which tapers towards its downstream end.

  In the fully open position of the valve, the downstream edge of the valve 16 at the end of travel closes the upstream opening

of the annular housing 22.

  The annular housing 22 is an integral part

  te of the star support 23, which has three flat arms

  dials 26, connecting the outer wall 25 to a peri-ring

  spherical 27 The arms 26 cross radially the flow channel The inner wall of the peripheral ring

  27 is substantially in the extension of the inner wall

  of the cylindrical section 13 of the body 10 On its outer wall, said ring 27 has an annular bulge 28, which corresponds to the groove 15 in which it comes to engage elastically when said ring 27 is forced into the zone d annular enlargement 14 of the body When the star support 23 is thus blocked in the body 10, its rear face is substantially in

  the extension of the downstream end of the body 10.

  A sealing ring 32, tightened against the end

  downstream of the body 10, ensures its tightness with respect to the adjacent tube of the pipe The whole of the body 10 is inserted into a tubular pipe 30 which has, at the end, an annular widening 31 where the

  enlargement zone 14 of said body Thus, the anti-valve

  return is blocked in an indecalable way in the axial direction inside the pipe 30 The important point is that the liquid, once it has penetrated inside the body 10, oe can leave it only by crossing the star support 23, since the wall of said body 10 extends, without discontinuity, over the entire length of the device and does not

  has no openings, no interruptions, no connecting devices

dement.

Claims (4)

  1 non-return valve comprising a body which forms a flow channel having a narrowing, a valve axially movable in said body, biased by a spring against the aforementioned narrowing with which it forms a sealed closure, finally a star support, mounted on said valve body, which extends inside   of said flow channel and on which said res-   comes out, the wall of the valve body being in one piece and   with no axial separation, characteristic   sée by the fact that the star support (23) is fixed, by a snap connection (15, 28), to the downstream end   of the body (10), its rear front face being free.   2 check valve according to claim 1, characterized in that at the downstream end of the body (10) is formed an annular enlargement zone (14), the star support (23) comprising a peripheral ring   (27), the inner face of which is substantially in the pro-   along the inner wall of the body (10).   3 check valve according to claim 2,   characterized by the fact that the peripheral ring (27) -   cooperates with the annular enlargement zone (14) by means of a snap-on assembly comprising   a groove (15) and a bulge (28).   4 Non-return valve according to one of the claims   1 to 3, characterized in that the body (10)   has, at all points, a wall of appreciable thickness   clearly constant and a symmetry of revolution, its cross section   axial having a profile which corresponds to a flow curve also from Laval.