EP2671126A2

EP2671126A2 - Gas pressure reducer with disk spring

Info

Publication number: EP2671126A2
Application number: EP12703036.9A
Authority: EP
Inventors: Sascha Pinger; Mario VELTE
Original assignee: Luxembourg Patent Co SA
Current assignee: Luxembourg Patent Co SA
Priority date: 2011-02-04
Filing date: 2012-01-31
Publication date: 2013-12-11
Also published as: LU91787B1; WO2012104274A3; CN103443728A; WO2012104274A2

Abstract

The invention is directed to a two-stage gas pressure reducer 2. It comprises a body 1 with an actuating rod 26 for actuating a shut-off valve, a first chamber 36 crossed by the rod 26 and delimited by a gas tight membrane 42 connected to the rod 26 and to the body 1. A disk spring 12 is placed on the membrane 42 and exerts a biasing force on the rod 26 against the force exerted by the gas on the membrane 42 in the first chamber 36. This constructions of pressure and/or flow reducer or at least controller allows a space reduction, provides a reduction of parts and a simplification of assembly.

Description

GAS PRESSURE REDUCER WITH DISK SPRING

Technical Field

[0001] The invention is directed to a gas pressure and/or flow control device.

More particularly, the invention is directed to a gas pressure reducer with a single stage or with two stages. Even more particularly, the invention is directed to a clip-on or screw-on pressure reducer for mounting on a bottle equipped with a gas shut-off valve.

Background Art

[0002] Patent document GB 869,098 discloses a two-stage fluid pressure reducing valve assembly. This assembly is a clip-on device for mounting on the neck of a bottle equipped with a shut-off valve. It comprises essentially a body, an actuating rod for actuating the shut-off valve of the neck of the bottle, a first chamber directly downstream of the neck shut-off valve and a second chamber downstream of the first chamber. A first membrane is attached to the body and to the rod, forming a border portion between the first and second chambers. A coil spring is arranged to exert a biasing force on the rod, the biasing force being directed to the neck shut-off means so as to open these means. Second shut-off means are arranged between the first chamber and the second chamber. This latter is delimited by a second membrane which actuates the second shut-off means. The bottle neck shut-off valve together with the rod actuated by the fluid pressure in the first chamber via the first membrane constitutes the first stage of the pressure reduction. The second shut-off valve actuated by the second membrane constitutes the second stage of the pressure reduction. This fluid pressure reducing valve assembly is particularly suitable for LPG products for the consumer market and also for industrial applications. The first stage of pressure reduction requires spring acting on the first membrane which has a certain stoke whilst showing a relatively high stiffness compared to the spring acting against the second membrane of the second stage. Indeed, when closing the valve assembly, a cam element at the top of the body is manipulated in order to lift the second membrane and also the rod against the biasing forces of the springs, and this to such an extent that the rod is not more in contact with the shut-off valve of the bottle neck. To that end, the coil spring is held by a spring housing which protrudes in the second chamber.

[0003] This teaching is more than 50 years old and has proven to be effective and reliable. The construction of this teaching requires however a certain space in height which is disadvantageous for various reasons. Indeed, there is a need for providing a fluid pressure reduction valve assembly which is more compact. Additionally, this construction requires a certain complexity due to the number of parts to be assembled in the second chamber.

Summary of invention

Technical Problem

[0004] The invention has for purpose to provide a gas pressure and/or flow control device which solves at least one of the drawbacks mentioned here above. More specifically, the invention has for objective to provide a gas pressure and/or flow control device which is more compact and/or more simple and cheaper to manufacture.

Solution to Problem

[0005] The invention has for object a gas pressure and/or flow control device comprising a body; an actuating rod for actuating first gas shut-off means; sealing means between the body and the rod allowing movement of the rod, the sealing means having a surface delimitating a first chamber with the body, the first chamber being downstream of the first shut-off means; biasing means exerting an elastic force on the actuating rod in a longitudinal direction of the rod opposed to an effort exerted on the rod via the sealing means by the pressure of the gas in the first chamber; wherein the biasing means comprise a disk spring arranged concentrically with the rod.

[0006] According to a preferred embodiment of the invention, the sealing means comprise first gas tight membrane attached to the body and to the rod. [0007] According to another preferred embodiment of the invention, the sealing means comprise a piston preferably sealingly received in the body.

[0008] According to another preferred embodiment of the invention, the disk spring comprises an external ring and a plurality of legs which are preferably oriented inwardly in a radial direction.

[0009] According to still another preferred embodiment of the invention, each leg extends inwardly from the external ring to a distal end so as to leave a free central portion, the free central portion being preferably circular.

[0010] According to a still another preferred embodiment of the invention, the disk spring is generally flat, preferably with an essentially constant thickness.

[0011] According to a still another preferred embodiment of the invention, the disk spring is arranged against the first membrane, the first membrane being preferably circular and concentric with the disk spring.

[0012] According to a still another preferred embodiment of the invention, the rod comprises an annular end in contact with the disk spring.

[0013] According to a still another preferred embodiment of the invention, the annular end of the rod in contact with the disk spring has a generally rounded, preferably half-rounded longitudinal cross-section.

[0014] According to a still another preferred embodiment of the invention, the attachment area of the first membrane to the rod is longitudinally distant from the contact area of the rod with the disk spring.

[0015] According to a still another preferred embodiment of the invention, the first membrane and the disk spring are distinct elements.

[0016] According to a still another preferred embodiment of the invention, the body comprises the first gas shut-off means.

[0017] According to a still another preferred embodiment of the invention, the gas pressure and/or flow control device is a clip-on device for being clipped on the neck of a gas bottle and for cooperating with the first gas shut-off means located in said neck.

[0018] According to a still another preferred embodiment of the invention, the gas pressure and/or flow control device is a two-stage pressure reducer, the body comprising a second chamber downstream of the first chamber, second gas shut-off means arranged fluidly between the first chamber and the second chamber, the second chamber being delimited by the first membrane and a second membrane, the second membrane acting on the second gas shut-off means.

[0019] According to a still another preferred embodiment of the invention, the second gas shut-off means comprise a seat formed in the body and a lever with a first end cooperating with the seat for shutting-off the gas passage between the first and second chambers and a second end mechanically linked to the second membrane.

[0020] According to a still another preferred embodiment of the invention, the gas pressure and/or flow control device comprises device operating means for displacing the rod against the biasing force of the disk spring in order to shut-off the flow of gas.

[0021] According to a still another preferred embodiment of the invention, the device operating means comprise an operating shaft arranged transversally to the rod and with an eccentric portion cooperating with the rod.

Advantageous effect of invention

[0022] The measures of the invention allow a simple and compact construction of a gas pressure and/or flow control device. Indeed, the use of a disk spring acting on an actuating rod of a shut-off valve as biasing means against the force exerted by the expanded gas renders the construction substantially more compact. Additionally, the use of this principle especially in combination with a membrane provides an additional advantage of reduction of parts and of simplicity for assembling.

[0023] The specific features of the disk spring in accordance with the invention provide a particularly efficient and suitable spring for such applications.

Brief description of drawings

[0024] Figure 1 is a top view of the first stage of a gas pressure reducer in accordance with the invention.

[0025] Figure 2 is a top view of the spring of the gas pressure reducer of figure 1.

[0026] Figure 3 is a cross sectional view of the gas pressure reducer of figure 1 along the cut line 3-3. Figure 3 comprises also a blow-up view of the membrane, spring and rod of the pressure reducer. [0027] Figure 4 is a front view and a top view of an alternative spring to the disk spring of figure 2.

[0028] Figure 5 is a top view of a complete two-stage gas pressure reducer in accordance with the invention.

[0029] Figure 6 is a cross sectional view of the gas pressure reducer of figure 5 along the cut line 6-6.

Description of embodiments

[0030] Figure 1 is a top view of the first-stage part of a gas pressure reducer 2 corresponding to an embodiment of the invention. The pressure reducer comprises a body 4 with an operating shaft 8, a gas inlet at a lower part (not visible in figure 1) and a lateral gas outlet 6 fluidly directly connected to a low pressure chamber 10. This chamber 10 is fed with gas from a gas inlet 14. A disk spring 12 is located at the centre of the chamber 10, attached to the body 4.

[0031] The disk spring 12 is illustrated in figure 2 where we can observe that it comprises an external ring portion 16 and a series of legs 18 extending inwardly from the ring portion. The legs 18 are distributed equally along the ring portion 16 so as to leave free spaces 20 between two consecutive or adjacent legs. In this particular case, the spring comprises 6 legs but could comprise less than 6 or also more than 6. Each leg 18 extends from the external ring portion 16 in a radial and generally straight manner. Each leg can however have a varying section or shape along its generally straight longitudinal axis. The distal end of each leg is distant from the center of the spring such as to leave a generally concentric and circular free area.

[0032] The disk spring is manufactured from material usual for this type of spring, like for example imported 50CrV4 steel. The disk spring can also be austempered. Austempering is an isothermal heat treatment that produces a lower Bainite microstructure or ausferrite and is primarily used to improve mechanical properties. Austempering is defined by both the process and the resultant microstructure.

[0033] The construction of the pressure reducer of figure 1 can be better understood by means of figure 3 which is a cross-sectional view along the line 3-3 of figure 1. The lower part of the body 1 comprises a cavity 32 for cooperating with a corresponding neck of a gas bottle or cylinder (not illustrated). The illustrated pressure reducer is a clip-on one in that it is designed to be slipped and clipped onto the bottle neck by a simple movement of downward engagement whilst lifting the outer ring 24 in order to allow the balls 30 to retract outwardly in a radial manner and allow a full engagement of the body 4 with the bottle neck. The release of the outer ring 24 will allow it to be lowered down due to its spring and will urge the balls 30 into a corresponding groove or shoulder portion of the neck, thereby securing the fixation of the body on the neck. Sealing means are provided either on the top portion of the neck or in the bottom part of the cavity 32, or on both, in order to provide a gas tight connection between both.

[0034] The pressure reducer 2 comprises a rod 26 slidably mounted in the body 4 along its longitudinal axis. This rod 26 comprises a lower portion 28 which is designed to come into contact with a corresponding rod of a gas shut-off valve (not illustrated) arranged in the bottle neck. Such a shut-off valve is a reversed seat valve, i.e. a valve that is designed such as to shut-off the gas passage by a movement of an element cooperating with a fixed valve seat which corresponds to a downstream direction of the gas when in service. In other words, the shut-off valve will be opened by a downward movement of the rod 26.

[0035] The body 4 comprises a passage 34 for the gas flowing at a high pressure from the bottle neck. It comprises a first chamber 36 for high pressure gas. This chamber 36 is crossed by the actuating rod 26 and delimited by a first membrane 42. This first membrane is gas tight and generally circular with a central hole. Its outer side is attached to the body and its inner side to the rod 26, both attachments being gas tight.

[0036] The disk spring 12 is placed on the membrane so as to urge the rod downwardly in the sense of opening the shut-off valve of the first stage.

[0037] The body 4 comprises a restricted gas passage 14 connecting the first chamber 38 with the second chamber 10. The first chamber 36 serves as a gas reservoir at an intermediate pressure, i.e. a pressure which is reduced compared to the pressure in the bottle or cylinder but however higher than the output pressure.

[0038] When the pressure reducer is in service, the spring 12 urges the rod downwardly in a position where its end 28 is in thrust contact with an actuation element of the shut-off valve of the bottle neck so as to open it and allow the gas to flow. When the intermediate pressure in the first chamber 36 increases, the resulting effort on the first membrane 42 increases and counteracts the urging force of the spring 12 and thereby lifts the rod 26. This reduces the flow section of the valve, the gas flow and therefore the pressure in the chamber 36. When the pressure in the chamber 36 decreases, the resulting effort on the membrane 42 diminishes and the spring 12 moves downwardly the rod 26 so as to increase the flow section of the valve, the gas flow and therefore the pressure in the chamber. This constitutes the basis of the first stage of pressure reduction of the pressure reducer described here.

[0039] The blow-up illustration of the central part of the pressure reducer shows with more details the arrangement of the spring, the membrane, the rod and the operating shaft 8. The body 4 forms a cylindrical seat for receiving the membrane 42 and the disk spring 12. This latter is placed directly on the membrane 42 in a concentric manner or indirectly with an intermediate protective layer. The membrane 42 is generally flat and circular with a central opening. The spring 12 is generally flat and circular with an approximately same diameter as the membrane, and with a central opening as already explained in relation with figure 2. The membrane is preferably made of elastomeric material. Both the membrane 42 and the spring 12 can be held in place in their seat in the body by a crimping action of body material on the washer 13 placed on the spring. The washer is substantially thicker as the spring in order to be able to support the crimping effort without any damages. The rod 26 is preferably assembled to the membrane prior to mounting the membrane and the spring on the body 4.

[0040] The rod 26 comprises a shoulder portion 45 for supporting the inner portion of the membrane 42. This shoulder portion is preformed with the rod. When the inner opening of membrane 42 is engaged on the rod 26 and on its shoulder portion 45, a washer 46 is then engaged on the rod and put under pressure against the membrane and held in place by a crimping action of the upper or distal end of the rod 26. Indeed, this distal end of the rod 26 is generally cylindrical and can therefore be easily deformed so as to create a collar 44 with a half-rounded longitudinal cross- section. This collar 44 holds the washer 46 against the membrane.

[0041] The membrane 42 can have one or more circular ribs on the contact surfaces with the body 4 or with the shoulder 45 of the rod 26. Similar negative ribs would then be formed on the supporting surfaces of the body or the rod. The purpose of this measure is to prevent any movement of the membrane which would remove it from its seating place in the body and/or on the rod.

[0042] Also, depending on different dimensioning factors, some additional intermediate joint or soft layer(s) or washer(s) may be used between the membrane, the spring and/or the seats in the body and on the rod.

[0043] As can be seen in the blow-up view in figure 3, the legs of the disk spring 12 are in contact on the rounded collar 44 of the rod 26, thus allowing a direct contact with minimum frictional forces.

[0044] The rod 26 comprises also a transversal slot 40 in which an eccentric end 38 of the operating shaft 8 engages. This shaft is rotatably supported by the body 4, so that its manipulation by rotation allows to lift the rod 26 against the urging force of the spring 12 and to thereby shut-off the device. When in the open position, the eccentric portion 38 of the operating shaft 8 is received in the corresponding slot 40 of the rod 26 with a vertical play so as to allow a free movement of the rod and a free functioning of the first stage of pressure reduction.

[0045] The above mentioned design is particularly advantageous with regard to the simplicity and the compactness of construction. Indeed, the space required for the disk spring is minimal whereas its specific design fulfills the requirements for its specific function. Additionally, the number of parts is limited and their assembly is particularly simple. [0046] The second chamber 10 in figure 3 is designed for receiving a cover portion of the pressure reducer in order to provide a second stage of pressure reduction. This second stage is not illustrated in relation with the pressure reducer body of figure 3 but will be explained in details in relation with figures 5 and 6 which illustrate a slight variation of the present pressure reducer.

[0047] Figure 4 illustrates an alternative design for the disk spring of the pressure reducer of the invention. The spring 112 still comprises an external ring 116 with radially extending legs 118. The spring comprises this time 9 legs 118 having each a triangular shape, so as to leave free spaces 120 between the legs with an approximately constant width. The distal ends of the legs 118 at distant from the central point of the disk spring so as to leave an essentially circular free space 122 at the center. Like the spring 12 of the pressure reduced illustrated in figures 1 and 3, the spring 112 is not perfectly flat but rather exhibits a conical form or a conical shell. Compared to a classical disk spring with a continuous surface, the inclusion of slots on either the inner or outer diameter creates a lever which works on the un-slotted portion of the spring. This has for effect to reduce the spring load and increase the deflection capacity. The resulting spring has a softer characteristic with a large deflection and in pro portion to the outside diameter smaller spring loads.

[0048] Figures 5 and 6 illustrate the complete two-stage pressure reducer corresponding to figures 1 and 3 and in accordance with the invention. Figure 6 is a cross-sectional view along the line 6-6 of figure 5. The cover part 52 of the body 4 is illustrated. The second stage of pressure reduction will therefore be briefly explained. Similarly as to what has been explained in connection with figure 3, when the pressure reducer is in service, the first chamber 36 is filled with gas at an intermediate pressure. This latter can escape the first chamber 36 into the second chamber 10 through the restricted passage 14, thereby being allowed to be expanded at a lower pressure. The restricted passage 14 forms a seat in the second chamber. The gas is allowed to flow from the first chamber 36 into the second chamber 10 as long as the articulated lever 48 keeps the sealing element 50 at least partially distant from the seat 14. When the pressure in the second chamber 10 increases, the resulting force on the second membrane 56 urges against the counter force of the spring 58 and lifts the connecting element 54. This latter is connected to the lever 48 so that the upward movement of the connecting element 54 will moves the lever to a closing position which will reduce or stop the flow of gas from the intermediate pressure.

[0049] The same principle applies when the pressure in the second chamber 10 diminishes being understood that the result will be an increase of the flow of gas from the first chamber to compensate the drop of pressure in the second chamber.

[0050] As can be seen in figure 6, the gain of space above the first membrane through the use of a disk spring is very advantageous because it allows to position the lever 48 at a much lower position and thereby to design a substantially more compact device.

[0051] Generally speaking, it is to be understood that the principle of the invention which has been described in relation with very a specific type of pressure reducer is also applicable to many other types of gas pressure and/or flow control devices.

Claims

Gas pressure and/or flow control device comprising

a body (1 );

an actuating rod (26) for actuating first gas shut-off means;

sealing means (42) between the body and the rod allowing movement of the rod, the sealing means having a surface delimitating a first chamber (36) with the body (1 ), the first chamber (36) being downstream of the first shut-off means;

biasing means (12) exerting an elastic force on the actuating rod (26) in a longitudinal direction of the rod opposed to an effort exerted on the rod via the sealing means (42) by the pressure of the gas in the first chamber (36);

characterized in that

the biasing means comprise a disk spring (12) arranged concentrically with the rod (26).

Gas pressure and/or flow control device according to claim 1 , characterized in that the sealing means comprise first gas tight membrane (42) attached to the body (1) and to the rod (26).

Gas pressure and/or flow control device according to claim 1 , characterized in that the sealing means comprise a piston preferably sealingly received in the body (1 ).

Gas pressure and/or flow control device according to any one of claims 1 to 3, characterized in that the disk spring (12; 112) comprises an external ring (16; 1 16) and a plurality of legs (18; 1 18) which are preferably oriented inwardly in a radial direction.

Gas pressure and/or flow control device according to claim 4, characterized in that each leg (18; 1 18) extends inwardly from the external ring (16; 1 16) to a distal end so as to leave a free central portion (22; 122), the free central portion being preferably circular.

6. Gas pressure and/or flow control device according to any one of claims 1 to 5, characterized in that the disk spring (12; 1 12) is generally flat, preferably with an essentially constant thickness.

7. Gas pressure and/or flow control device according to any one of claims 1 to 6, characterized in that the disk spring (12; 1 12) is arranged against the first membrane (42), the first membrane being preferably circular and concentric with the disk spring.

8. Gas pressure and/or flow control device according to any one of claims 1 to 7, characterized in that the rod (26) comprises an annular end (44) in contact with the disk spring (12).

9. Gas pressure and/or flow control device according to claim 8, characterized in that the annular end (44) of the rod (26) in contact with the disk spring has a generally rounded, preferably half-rounded longitudinal cross-section.

10. Gas pressure and/or flow control device according to any one of claims 8 and

9, characterized in that the attachment area of the first membrane (42) to the rod (26) is longitudinally distant from the contact area of the rod (26) with the disk spring (12).

1 1. Gas pressure and/or flow control device according to any one of claims 1 to

10, characterized in that the first membrane (42) and the disk spring (12) are distinct elements.

12. Gas pressure and/or flow control device according to any one of claims 1 to

1 1 , characterized in the body (1) comprises the first gas shut-off means.

13. Gas pressure and/or flow control device according to any one of claims 1 to 1 1 , characterized in that the gas pressure and/or flow control device is a clip- on or screw-on device for being clipped or screwed on the neck of a gas bottle and for cooperating with the first gas shut-off means located in said neck.

14. Gas pressure and/or flow control device according to any one of claims 1 to 13, characterized in that the gas pressure and/or flow control device is a two- stage pressure reducer, the body (1 ) comprising a second chamber (10) downstream of the first chamber (36), second gas shut-off means (14, 48, 50) arranged fluidly between the first chamber (36) and the second chamber (10), the second chamber (10) being delimited by the first membrane (42) and a second membrane (56), the second membrane acting on the second gas shut- off means.

15. Gas pressure and/or flow control device according to claims 14, characterized in that the second gas shut-off means comprise a seat (14) formed in the body (1 ) and a lever (48) with a first end (50) cooperating with the seat for shutting- off the gas passage between the first and second chambers and a second end mechanically linked to the second membrane (56).

16. Gas pressure and/or flow control device according to any one of claims 1 to 15, characterized in that the gas pressure and/or flow control device comprises device operating means (8) for displacing the rod (26) against the biasing force of the disk spring (12) in order to shut-off the flow of gas.

17. Gas pressure and/or flow control device according to claims 16, characterized in that the device operating means comprise an operating shaft (8) arranged transversally to the rod (26) and with an eccentric portion (38) cooperating with the rod (26).