Check valve

Abstract

The invention relates to a check valve (1) comprising: - a body (10) defining a flow channel (CE) for fluid (F) and internally delimiting a valve seat (11); and - a valve element (20) mounted so as to be able to move in translation in the flow channel between an open position, in which the valve element is set back from the valve seat, and a closed position, in which the valve element is in sealed contact with the valve seat, wherein the valve element comprises a valve head and a rod (22) which projects axially from the valve head and is slidably mounted in a guide tube (14), characterised in that the guide tube comprises a first end and a second end respectively which, together with the rod, respectively define a first damping chamber and a second damping chamber (CH1, CH2), wherein the chambers have variable volumes and are in fluid communication with the flow channel via, respectively, a first fluid channel and a second fluid channel (C1, C2) arranged so as to damp any displacement of the valve element.

Description

[0001] Description

[0002] Title of the invention: Non-return valve

[0003] The present invention relates to valves for circuits through which fluids flow, in particular gaseous fluids, and more particularly concerns non-return or flow control valves.

[0004] BACKGROUND OF THE INVENTION

[0005] As is well known, a non-return valve, also called a "check valve", imposes a direction of flow on the fluids that pass through it and is used to prevent the return of a fluid within a system.

[0006] A non-return valve typically includes:

[0007] - a body defining a fluid flow channel between an inlet port and an outlet port of the body; and

[0008] - a valve mounted movable in translation in a guide arranged inside the body, between an open position in which the valve allows the flow of fluid, and a closed position in which said valve prevents the flow of fluid and towards which the valve is returned by a spring.

[0009] If the pressure in the system exceeds the spring's stiffness, the valve moves from the closed position to the open position until it reaches an operating position, allowing fluid to flow. If the pressure in the system then falls below the spring's stiffness, or if the flow direction changes, the valve automatically returns to the closed position and prevents fluid from passing through.

[0010] The flow rate and pressure of the fluid are generally not perfectly constant and experience slight variations, resulting in slight oscillations of the valve around the operating position during operation.

[0011] However, these oscillations can have such high amplitudes that the valve repeatedly strikes its guide, causing the latter to break. OBJECT OF THE INVENTION

[0012] The invention aims to provide a non-return valve that at least partially overcomes the aforementioned drawbacks.

[0013] SUMMARY OF THE INVENTION

[0014] To this end, a non-return valve is proposed, comprising:

[0015] - a body that defines a fluid flow channel between a first end and a second end of the body and that includes an internal surface delimiting a valve seat; and

[0016] - a valve mounted movable in translation in the flow channel of the body between an open position in which the valve is recessed from the valve seat, and a closed position in which the valve is in tight contact with the valve seat and towards which the valve is returned by an elastic return member.

[0017] The valve comprises a valve head and a stem which extends axially from the valve head and is slidably mounted in a guide tube connected to the body, defining fluid passages.

[0018] According to the invention, the guide tube comprises a first end and, opposite it, a second end, respectively defining with the stem a first damping chamber and a second damping chamber having volumes that vary according to the position of the valve. The first chamber and the second chamber are in fluidic communication with the flow channel via a first fluidic channel and a second fluidic channel respectively, arranged to dampen any displacement of the valve around an operating position arranged between the closed and open positions.

[0019] The first chamber and the second chamber serve to limit the amplitude of the valve's oscillations around its operating position, thus limiting the impacts between the valve and the guide tube. This reduces wear on the stem and the risk of breakage of the guide tube or its connections to the body.

[0020] According to a particular feature, the valve includes an annular skirt extending axially from the valve head and around the first end of the guide tube to delimit the first chamber.

[0021] In particular, the first end of the guide tube and the skirt form the first fluidic channel.

[0022] According to another particular feature, the second end of the guide tube includes a bottom delimiting the second chamber.

[0023] In particular, the bottom of the guide tube includes a hole forming the second fluidic channel.

[0024] According to another particular feature, the guide tube is connected to the body by fins extending radially from said guide tube.

[0025] According to another particular characteristic, the body is generally tubular in shape and extends along the axis of translation of the valve.

[0026] According to another particular feature, the valve head includes an external rim defining an annular groove in which a sealing gasket is received, arranged to ensure a tight seal between the valve head and the valve seat when the valve is in the closed position.

[0027] BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The invention will be better understood in light of the following description, which is purely illustrative and not limiting, and should be read in conjunction with the accompanying figures, among which:

[0029] [Fig.1] Figure 1 is an axial cross-sectional view of a non-return valve according to a particular embodiment of the invention, in which the valve is in the closed position;

[0030] [Fig.2] Figure 2 is an identical view to Figure 1 in which the valve is in the open position.

[0031] DETAILED DESCRIPTION OF THE INVENTION

[0032] With reference to Figure 1, a non-return valve 1, according to a particular embodiment of the invention, comprises:

[0033] - a body 10, generally tubular, which extends along an axis X to define a fluid flow channel CE and which has an internal surface defining a valve seat 11; and

[0034] - a valve 20 mounted movably axially in the body 10 between an open position in which the valve 20 is recessed from the valve seat 11 (figure 2), and a closed position in which the valve 20 is in tight contact with the valve seat 11 (figure 1) and towards which the valve 20 is returned by a helical spring 30.

[0035] The body 10 has a first end 10.1 defining an inlet or intake port for a fluid and, opposite, a second end 10.2 defining an outlet or exhaust port for the fluid.

[0036] For assembly purposes, the body 10 is here made in two parts, namely a first part 10a and a second part 10b. The first part forms a first section of the body 10 and has a free end corresponding to the first end 10.1 of said body 10. The second part 10b forms a second section of the body 10 and has a free end corresponding to the second end 10.2 of said body 10. The first part 10a and the second part 10b of the body 10 are rigidly connected to each other by screws 12. The first part 10a includes an end face having an annular groove in which an O-ring seal 13 is axially received in tight contact with an end face of the second part 10b of the body. The sealing gasket 13 is axially compressed between a bottom of the groove and the end face of the second part 10.2 to ensure a tight contact between the first part 10.1 and the second part 10.2.

[0037] The valve 1 further includes a guide tube 14 for the valve 20. The guide tube 14 extends along the X-axis within the second portion 10b of the body 20 and is connected to said second portion 10b of the body 10 by fins 15 extending radially from a central portion of the guide tube 14. The fins 15 are evenly distributed around the X-axis and, together with an internal surface of the second portion 10b of the body 10, define fluid passages. The guide tube 14 and the fins 15 are integral with the body 10.

[0038] The guide tube 14 includes an internal shoulder 14.3 defining a first bore 14.1 of large diameter and a second bore 14.2 of small diameter. The first bore 14.1 has a free end opening into the first part 10a of the body 10 and receives two sliding bearings 16 arranged, as will be seen later, to allow the valve 20 to slide along the X-axis inside the body 10. The bearings 16 have an internal diameter slightly smaller than the diameter of the second bore 14.2. One of the bearings 16 is in contact with the shoulder 14.3 defining the first bore 14.1 and the second bore 14.2, and the other bearing 16 is slightly recessed from the free end of the first bore 14.1. The second bore 14.2 includes a free end having a bottom 17 on which is formed a hole 18 extending along the X axis and opening into the second part 10b of the body 10.

[0039] The valve 20 extends along the longitudinal X axis of the body 10 and includes a valve head 21 and a stem 22 extending axially from the valve head 21, towards the second end 10.2 of the body 10.

[0040] The valve head 21 is substantially in the shape of a truncated conical disc pointing towards the first end 10.1 of the body 10. This disc includes an outer rim defining an annular groove 21.1 in which is received a sealing gasket 23 arranged to ensure a tight contact between the valve head 21 and the valve seat 11 when the valve 20 is in the closed position (figure 1): an external peripheral portion of the sealing gasket 23 is compressed between a lateral wall of the annular groove 21.1 and the valve seat 11.

[0041] The stem 22 is generally cylindrical in shape and is formed from the same material as the valve head 21. The stem 22 includes a shoulder 22.3 that delimits a first stem portion 22.1 of large diameter and a second stem portion 22.2 of small diameter. The first stem portion 22.1 is directly connected to the valve head 21, and the second stem portion 22.2 includes a free end that forms a free end of the stem 22.

[0042] The stem 22 receives a sleeve 24, which is lightly press-fitted onto an outer circumference of the first stem portion 22.1. The sleeve 24 has a first end in contact with the valve head 21 and, opposite it, a second end that fits around an end portion of the guide tube 14 to define a first annular fluidic channel Ci. The sleeve 24 forms a skirt extending axially from the valve head 21 and includes an internal surface that, together with the shoulder 22.3 of the stem 22, the second stem portion 22.2, and the end portion of the guide tube 14, defines a first variable-volume damping chamber CHi. The first chamber CHi is in fluidic communication with the flow channel CE, which is defined by the body 10, via the first fluidic channel Ci, which is defined by the sleeve 24 and the guide tube 14.

[0043] The second stem portion 22.2 is slidably mounted in the guide tube 14 via the bearings 16. It is understood that the bearings 16 provide translational guidance for the valve 20 along the X-axis. The free end of the stem 22 extends into the second bore 14.2 and, together with said second bore 14.2 and the bottom 17 of said second bore 14.2, defines a second variable-volume damping chamber CH2. The second chamber CH2 is in fluidic communication with the flow channel CE, delimited by the body 10, via a second cylindrical fluidic channel C2, delimited by the hole 18.

[0044] The helical spring 30 has a first end bearing against an external shoulder of the sleeve 24 and, on the opposite side, a second end bearing against an end face of the fins 15, so as to exert, via the sleeve 24, a restoring force on the valve head 21 tending to return the valve 20 to the closed position.

[0045] The operation of valve 1 will now be detailed.

[0046] The first end 10.1 and the second end 10.2 of the body 10 are respectively connected to a pressurized fluid supply conduit F and a flow conduit. The fluid F entering the valve 1 through the first end 10.1 of the body 10 exerts an axial force on the valve head 21 tending to move the valve 20 from the closed position to the open position against the spring 30. The position of the valve 20 is a function of the pressure of the fluid F:

[0047] - when the pressure of the fluid F entering the body 10 is less than or equal to a predetermined pressure, the valve 20 is, under the action of the spring 30, in the closed position in which the valve head 21 opposes the flow of the fluid F through the body 10, the axial force exerted by the fluid F on the valve head 21 being substantially equal to or less than the restoring force exerted by the spring 30 on said valve head 21 via the sleeve 24; and

[0048] - when the pressure of the fluid F entering the body 10 is greater than the predetermined pressure, the valve 20 is or reaches an operating position which is arranged between the closed position and the open position and in which the valve head 21 does not oppose the flow of the fluid F through the body 10, the axial force exerted by the fluid F on the valve head 21 being substantially equal to the restoring force exerted by the spring 30 on said valve head 21 via the bushing 24.

[0049] In service, the valve 20 tends to oscillate axially around the operating position, particularly in response to slight variations in the flow rate of the fluid F entering the body 10.

[0050] The slight movement of the valve 20 from the operating position to the open position causes a slight decrease in the volume of the first chamber CH1 and the volume of the second chamber CH2, and therefore a compression of the fluid contained in the first chamber CH1 and the fluid contained in the chamber CH2 which opposes the movement of the valve 20. The fluid contained in the first chamber CH2 and the fluid contained in the second chamber CH2 then tend to escape respectively through the first fluidic channel Ci delimited by the sleeve 24 and the guide tube 14 and through the second fluidic channel C2 delimited by the hole 18.

[0051] The slight movement of the valve 20 from the operating position to the closed position causes a slight increase in the volume of the first chamber CHi and the volume of the second chamber CH2, and therefore an expansion of the fluid contained in the first chamber CHi and the fluid contained in the second chamber CH2, which opposes the movement of the valve 20. The fluid F contained in the flow channel CE delimited by the body then tends to pass into the first chamber CHi and into the second chamber CH2 via respectively the first fluidic channel Ci delimited by the sleeve 24 and the guide tube 14 and via the second fluidic channel C2 delimited by the hole 18.

[0052] It is understood that the first chamber CH1 and chamber CH2 act as shock absorbers, limiting the amplitude of the oscillations of the valve 20 around its operating position and thus limiting the impacts between the valve 20 and the guide tube 14 (particularly between the shoulder 22.3 of the valve stem 22 and the end portion of the guide tube 14). Wear on the stem 22 and the bearings 16, and the risk of breakage of the fins 15, are thereby reduced.

[0053] As is known, the depreciation rate generated by the first chamber CH1 and that generated by the second chamber CH2 are respectively a function of:

[0054] - the dimensions of said first chamber CHi and those of the first fluidic channel Ci; and

[0055] - the dimensions of said second chamber CH2 and those of the second fluidic channel C2.

[0056] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0057] Spring 30 can be replaced by any elastic return mechanism or device (Belleville washers, wave washers, etc.)

[0058] The sleeve 24 can be replaced by an annular skirt extending axially from the valve head 21 or by a tubular extension extending axially from the guide tube 14, so as to form the first chamber CHi.

[0059] Although here the hole 18 extends axially into the bottom 17 of the guide tube 14, it can also extend radially at one end of said guide tube 14, in the vicinity of said bottom 17.

Claims

DEMANDS 1. Non-return valve (1) comprising: - a body (10) that defines a fluid flow channel (CE) (F) between a first end (10.1) and a second end (10.2) of the body and that includes an internal surface delimiting a valve seat (11); and - a valve (20) mounted to move in translation along an axis (X) in the flow channel of the body between an open position in which the valve is recessed from the valve seat, and a closed position in which the valve is in tight contact with the valve seat and towards which the valve is returned by an elastic return member (30), the valve comprising a valve head and a stem (22) which extends axially from the valve head and which is slidably mounted in a guide tube (14) connected to the body by defining fluid passages, characterized in that the guide tube comprises a first end and, opposite, a second end defining respectively with the stem a first damping chamber (CHi) and a second damping chamber (CHi) having volumes varying according to the position of the valve,the first chamber and the second chamber being in fluidic communication with the flow channel (CE) via respectively a first fluidic channel (Ci) and a second fluidic channel (Ci) arranged to dampen any displacement of the valve around an operating position arranged between the closed position and the open position.

2. Check valve (1) according to claim 1, wherein the valve (20) comprises an annular skirt (24) extending axially outward from the valve head (21) and around the first end of the guide tube (14) to delimit the first chamber (CHi).

3. Non-return valve (1) according to claim 2, in in which the first end of the guide tube (14) and the skirt (24) form the first fluidic channel (Ci).

4. Check valve (1) according to any one of the preceding claims, wherein the second end of the guide tube (14) comprises a bottom (17) delimiting the second chamber (CHi).

5. Non-return valve (1) according to claim 4, wherein the bottom (17) of the guide tube (14) includes a hole (18) forming the second fluidic channel (Ci).

6. Check valve (1) according to any one of the preceding claims, wherein the guide tube (14) is connected to the body (10) by fins (15) extending radially from said guide tube.

7. Check valve (1) according to any one of the preceding claims, wherein the body (10) is generally tubular in shape and extends along the axis (X) of translation of the valve (20).

8. Check valve (1) according to any one of the preceding claims, wherein the valve head (21) comprises an outer contour defining an annular groove (21.1) in which is received a sealing gasket (23) arranged to ensure a tight contact between the valve head and the valve seat (11) when the valve (20) is in the closed position.

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