Abstract:
The invention relates to a device for regulating the flow rate and/or pressure of a fluid, such as valve for a pressure gas cylinder, comprising a reducing valve including a first plug designed to be moved in the normal flow direction of the fluid during closure. The reducing valve also comprises a plunger to which the plug is coupled. The face of the plunger that is oriented towards the first plug defines a regulation chamber together with the body. The aforementioned face also comprises a seal that engages with a corresponding surface of the body such as to form a second plug for maintaining residual pressure. The regulation device also comprises a means for preloading and releasing a spring acting on the opposite face of the plunger.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present invention is the US national stage under 35 U.S.C. §371 of International Application No. PCT/EP2013/064274, which was filed on Jul. 5, 2013, and which claims the priority of application LU 92040 filed on Jul. 9, 2012 the content of which (text, drawings and claims) are incorporated here by reference in its entirety. 
     FIELD 
     The invention relates to a flow and/or pressure control device for a fluid such as a pressurized gas. More particularly, the invention relates to a pressure-reducing valve for pressurized gas. 
     BACKGROUND 
     In the field of pressurized gas storage, particularly for storing in bottles or cylinders of some gases used in the medical field such as oxygen, it is common to provide a residual pressure function on the valves disposed on the bottles. It is basically a check-valve type device with a valve or shutter subjected to a closure elastic force and configured to open when the pressure in the bottle exceeds a rather low given value of the order of few bars. The purpose of this device is to prevent from putting the bottle in direct connection with air when empty. Indeed, in the absence of such a device, when the bottle is empty and the valve is left open, the ambient air of the bottle can come into contact with the inside of the bottle and thus potentially contaminate it. In addition, by connecting the valve outlet to a source of pressurized gas, it may also be possible to at least partially refill the bottle with a potentially contaminating gas. The above mentioned device allows a connection between the inside and the outside of the bottle only when in the presence of a service flow rate, which in practice prevents contamination against the service flow. It also prevents unauthorized forced refilling. 
     The patent document GB 2349200 A discloses a pressure-reducing valve for a bottle of pressurized gas, with a residual pressure function. The valve essentially comprises a body with a connector to be screwed on a bottle neck, an outlet and a passage connecting the inlet to the outlet. The valve also includes a refilling adapter with a check-valve in connection with the passage. It also includes a shut-off valve in the passage downstream of the branch with the refilling connection, and a pressure reducer disposed downstream of the shut-off valve. It also includes a flow rate selector in the form of a disk with calibrated holes, rotatably driven by a hand-wheel distinct from the hand-wheel of the closing valve. The residual pressure function is integrated in the pressure reducer. This latter includes a shutter mechanically connected to a mobile piston defining with the body a control chamber. The gas under pressure upstream of the shutter flows through a restricted passage and is expanded when passing the shutter in an intermediate position. It then flows through the piston to fill the control chamber defined by the upper face of the piston. If the gas pressure is too high, the resultant force on the piston will move it downwards so as to reduce the flow section of the shutter and vice versa. The upper face of the piston also comprises a concentric ring passage for the gas, this seal being intended to sealingly cooperate with a seat on a portion of the body opposite to the piston. The latter is subjected to an elastic force of a spring which tends to bring the seal in question closer to the seat and to open the shutter. In state of rest, the shutter is opened, which allows the passage of gas through the regulator to the seal in sealing contact with the seat. The hydraulic surface of the piston at the level of the seal in question is slightly greater than the opposite hydraulic surface on the side of the shutter. These two surfaces being subjected to the same pressure, the positive difference of surface between the upper face and the lower face of the piston generates a force directed downwards by lowering the piston and opening the passage between the seal and the seat. These thus form an integrated residual pressure valve in the regulator. The valve of this teaching is therefore particularly interesting from the standpoint of integration of the residual pressure function. However, it is a quite complex and bulky structure particularly because of the presence of the side closure valve. 
     Patent document U.S. Pat. No. 7,814,931 B2 discloses a flow control device for a fluid, particularly liquid, in particular for sprayers. This device is working at much lower pressures than in the above discussed teachings. The device comprises a body with a first element movable in translation and connected to the body via a sealed membrane. The first movable element is subjected to an elastic force tending to move towards a first seat formed in the body. The membrane is specifically designed to work with this seat. In the rest position, the spring holds the membrane in contact with the circular seat. The fluid passage through the first seat and is sealed by the membrane. The device further comprises a second movable member mechanically connected to the first one and cooperating with a second seat upstream of the first seat. The second movable member has the effect of modulating the fluid passage section upstream of the first seat and the first movable member. When it is decided to open the device, part of the elastic force tending to press the first movable member towards his seat is released. The fluid pressure at the inlet of the device applied to the membrane may move the first member and open the passage. If the pressure and therefore the flow weaken, the passage will be reduced in order to maintain pressure. If the pressure is weakening too much, the passage will automatically close, preventing from having a flow with a low flow rate. This teaching shows an interesting principle that a mobile element flow regulator can provide, namely the closure of the passage at a too low flow rate. However, it does not provide a secure closure of the passage as a significant input pressure is likely to move the first element and open the passage. 
     SUMMARY 
     The invention aims to provide a flow and/or pressure control device for a fluid able to achieve, in addition, a shut-off function and a residual pressure function in a simple and reliable fashion. 
     The invention is directed to a control device of the flow and/or pressure of a fluid, comprising:
         a body with an inlet, an outlet and a passage connecting the inlet to the outlet;   a first shutter of the passageway;   a movable element mechanically connected to the first shutter with a face defining with the body a control chamber downstream of the first shutter and comprising a portion adapted to come into contact in a fluid tight manner with the body to form a second shutter of the passageway;   first resilient means acting on the movable member, e.g., a pistion, in the opening direction of the first shutter and closing direction of the second shutter; wherein       

     the first shutter is configured to close the passage by a movement substantially in the normal direction of flow of the fluid; and the first resilient means can be rendered inactive so as to allow closing of the first shutter and opening the second shutter. 
     According to various embodiments, the device comprises a second resilient means acting on the movable member in a direction of closing the first shutter and opening the second shutter. 
     According to various embodiments, the portion of the movable member forming the second shutter forms a closed perimeter with an average diameter that is lower, for example, by less than 50%, e.g., by less than 40%, e.g., by less than 30%, than that of the surface of the face of the movable member delimiting the control chamber. 
     According to various embodiments, the portion of the movable member forming the second shutter has a conical profile and the portion of body cooperating with the portion of the movable member has a corresponding conical profile. 
     According to various embodiments, the device comprises a circular seal housed in a groove formed in the conical portion of the movable member and/or of the body. 
     According to various embodiments, the device comprises a means for preloading and releasing the first resilient means, the first shutter closing and the second shutter opening under the force of the second resilient means when the first resilient means is released. 
     In various embodiments the preloading means comprises a rotatable control wheel, a slider acting on the first resilient means and a means for converting the rotational movement of the control wheel into translational motion of the slider. The slider can be arranged on the side of the first resilient means, opposite to the movable member. 
     In various embodiments the preloading means is configured not to present a stable position between two positions, one being the release of the first resilient means and the other being a preload of the resilient means. 
     According to various embodiments, the second resilient means comprises a spring disposed in the control chamber and bearing on the body. 
     According to various embodiments, the face of the movable member delimiting the control chamber and comprising the portion forming the second shutter is directed towards the first shutter. 
     According to various embodiments, the body comprises a portion projecting into the control chamber, the portion housing at least partially the first shutter and cooperating with the portion of the face of the movable member forming the second shutter. 
     According to various embodiments, the spring of the second resilient means is at least partially disposed around the body portion projecting into the control chamber. 
     According to various embodiments, the first shutter is adapted to sealingly cooperate with a seat in the passage and extends through the seat until upstream thereof. 
     According to various embodiments, the device comprises a third shutter disposed upstream of the first shutter and configured to close the passageway by movement essentially in the normal direction of flow of the fluid, the first and third shutters being configured to mutually cooperate so that the third shutter closes before the first one. 
     According to various embodiments, the third shutter is adapted to sealingly cooperate with a specific seat in the passage and extends through the seat from an upstream position to a downstream position of the seat so that the first shutter can come into contact with the third shutter. 
     According to various embodiments, the device is dimensioned so that in a service configuration the second shutter closes when the pressure at the inlet is less to 20 bar, for example, 10 bar, e.g., 5 bar. 
     According to various embodiments, the device is a valve for gas cylinder, capable to work at pressures above 50 bar, for example 100 bar, e.g., 150 bar. 
     The measures of the invention enable to provide a control device such as a regulator with integrated shut-off function and integrated residual pressure function. Indeed, the configuration of the first shutter such that it naturally closes with the pressure at the inlet of the apparatus ensures a reliable shut-off function. This function can be made safer by adding an additional shutter. The provision of the residual pressure valve on the movable element, in practice the piston, of the pressure regulator, and that on the face of the movable element facing the first shutter, reduces to a minimum the separation distance of the passage for the gas between the shutter of the pressure reducer and the shutter of the residual pressure. Reducing the length and thus the volume of this passage increases the protection that the residual pressure function is designed to provide to the internal volume of the bottle. Indeed, upon actuation of the means for preloading and releasing the first spring acting on the movable part of the pressure reducer, the passage between the position where the first shutter is closed and the second shutter is open to the opposite position, that is to say where the first shutter is opened and the second shutter is closed, causes during a fraction of a second a passage between the interior of the bottle and the external atmosphere. It is therefore important to minimize the volume between the two shutters. 
    
    
     
       DRAWINGS 
         FIG. 1  is a longitudinal sectional view of a flow and/or pressure control device for a fluid, according to various embodiments of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a flow and/or pressure control device  2  of a fluid. This is a longitudinal sectional view showing the main elements of the device  2  relating to the invention, some of these elements that are not directly related to the invention are not illustrated. 
     In various embodiments, the device  2  illustrated in  FIG. 1  can be a gas pressure reducing device for a pressurized gas that is, among others, stored in a bottle. In various implementations the device  2  can comprise a connector (not shown) with a male portion to be screwed to the neck of a bottle of pressurized gas. 
     In various embodiments, the device  2  comprises a body  4  in which is formed a passage connecting a gas inlet  6  with a gas outlet  8 . The concept of entry is associated with the device shown here, except that it can include other features not visible in  FIG. 1  due to the cutaway view. These other functions can then be such as to “move” the inlet  6  of the device  2  to a further upstream portion, in particular to a male part intended to be screwed on the neck of a bottle of pressurized gas and discussed above. The gas outlet  8  is illustrated in an incomplete fashion. In the specific case of  FIG. 1 , the gas outlet  8  includes a flow selector in the form of a rotating disc with calibrated orifices, known per se to the skilled person. However, it is understood that other forms of outlet  8  can be considered, such as including a single outlet without flow selector. 
     In various embodiments, the device  2  comprises a shut-off device of the passage consisting of a first shutter  18  and an additional shutter  12 , cooperating, each, with a seat  20  and  14 , respectively. These two shutters  12  and  18  are of the inverted seat type, i.e. where the direction of movement of the shutter towards closing of the passage corresponds to that of the fluid flow during normal service. The shutters will be described in detail later. 
     In various embodiments, the control device  2  also includes a piston  22  sealingly (via a seal  30 ) movable in translation in a cylindrical housing formed in the body  4 . The lower face of the piston  22  defines with the body  4  a control chamber  26 . The first shutter  18  is mechanically and rigidly connected to the piston  22 . The latter also includes a seal  28  disposed on a conical portion concentric with the longitudinal axis of the piston  22  and the shutter  18 . This seal  28  is housed in a groove formed in the conical portion and is intended to sealingly cooperate with a corresponding conical portion of the body into the control chamber  26 . The seal  28  and the corresponding tapered portion serving as a seat form a second shutter providing a residual pressure function. 
     The piston  22  is subject on its upper side to a resilient force of the first resilient means, precisely a first spring  32 , tending to open the first shutter  18  and to close the second shutter  24 ,  28  of residual pressure. The piston  22  is also subject to its underside to an elastic force of second resilient means, precisely the second spring  24 , opposite to the first resilient means and thus tending to close the first shutter  18  and to open the second shutter  24 ,  28  of residual pressure. 
     The elastic force of the first spring  32  can be controlled by the control wheel  36  disposed at the top of the control device. In effect, the wheel  36  comprises two vertical grooves  34  formed on in its inner surface. Each of these grooves  34  cooperates with a pin  38  passing through an inclined groove formed in the sleeve  40  (the inclination of these grooves is not visible in the FIGURE). Each of the pins  38  is received or embedded in a slider  44  comprising in its center an adjustable pressure screw  50  on which a cup is supported via a ball  52 . The latter is intended to enable a compression force transmission according to the longitudinal axis of the device  2  while minimizing the torque transmission of rotational force when the slider  44  moves in a combined movement of translation and rotation. Indeed, when the wheel  36  is rotated, the vertical grooves  34  transmit the rotation force to the pins  38  and the slider  44 . The forced movement of the pins  38  along the inclined grooves formed in the sleeve  40  then imposes this combined movement of translation and rotation of the pins and thus also the slider  44 . The cup supports the upper end of the first spring  32 . The rotation of the wheel  36  can change the load of the spring  32  in question. 
     Although this is not visible in  FIG. 1 , the inclined grooves formed in the sleeve  40  each include a lower end with a stop notch. These stop notches are designed to allow a steady stop of the slider  44  in the down position, that is to say, a position of preload of the spring  32 . In various implementations, the upper ends of the grooves can comprise no notches. Indeed, the control device comprises a third spring  42  housed in the sleeve and acting on the slider  44 . When the wheel  36  is manipulated to disengage the pins  38  of the notches of the grooves, the combined elastic force of the springs  32  and  42  moves back the slider  44  upwardly while rotating the wheel  36 . Once the first spring  32  is released, the third spring  42  is sized to exert a permanent elastic force on the slider  44  so as to maintain a mechanical clearance between it and the first spring  32 . This makes it possible to ensure full relaxation of any elastic force on the piston  22  directed in the opening direction of the first shutter  18 . 
     The sleeve  40  can be formed by two moulded plastic or composite parts, in the form of half shells. They can be symmetrical and comprise a flat surface at their lower groove cooperating with a rim of the body  4 , so as to secure the sleeve  40  against rotation. During assembly, after assembly of the two half-shells, the wheel  36  is slid onto the outer cylindrical surface of the sleeve  40  and is held in place by a snap clip  46 . This latter also stabilizes the assembly of the two half shells. A cover  48  can be disposed on the wheel  36 . The pressure screw  50  can be adjusted via a tool cooperating in rotation with its upper end and by releasing the lock nut. This setting can be achieved in service when the first spring  32  is in the preloaded state. 
     As shown in  FIG. 1 , the control device  2  is in the closed state; that is to say that the compression force of the first spring  32  is completely released. The third spring  42  maintains the slider  44  in the upper position. The second spring  24  keeps the piston  22  in the upper position and the shutter in the closed position. More specifically, the first shutter  18 , which is coupled to the piston  22 , is pressed against its seat  20  under the force of the spring  24 . The second shutter  24 ,  28  of residual pressure is open. The additional shutter  12  constituting a third shutter is also in the closed position under the action of the spring  10  and the absence of force opposed by the first shutter  18 . The shutter device is doubly shut-off and thus provides a level of high security. 
     When it is desired to put the device  2  into operation in order to output gas, the wheel  36  is manipulated to set the slider  44  in the lower position. With reference to what has been mentioned previously, this lower position is a stable and predefined position. The spring  32  is preloaded and then exerts a force on the piston  22  which is directed downwardly. The closure device opens, more precisely the first shutter  18  opens and comes into contact with the rod  16  of the third shutter  12 . The downward movement of the first shutter  18  after contacting the third shutter has for effect to open the third shutter. The pressurized gas can then flow along the passage through the respective seats  14  and  20  of the third and the first shutter  12  and  18 . Pressure can then be established in the control chamber  26  before the second shutter  24 ,  28  can close. This pressure prevents the descent of the piston  22  to a closing of the shutter  24 ,  28  provided that a minimum pressure is present upstream of the device, that is to say in the bottle. Indeed, the pressure in the control chamber  26  acts on a large area generating a force capable of overcoming the resultant force of the spring  32  acting on the opposite face of the piston  22 . In case of pressure drop upstream of the regulator, to such an extent that it becomes smaller than the range of operating pressure of the control chamber  26 , the pressure therein will then no longer balance the force of the spring  32  and the piston  22  will move down until the shutter  24  and  28  of residual pressure closes. The first and third shutters  18  and  12  are then wide open. The gas can no longer pass and the inside the bottle to which the control device  2  is connected remains isolated from the external atmosphere. 
     Before refilling, the wheel  36  is normally manipulated to release the preload of the spring  32  and to allow the upward movement of the piston  22  under the force of the spring  24  and thereby closing the shutter device  18 ,  12 . 
     For refilling the bottle, a specific connector connected to the inlet  6  of the control device  2  via a suitable valve can be used. Such a valve is partially visible in the lower left of  FIG. 1 . It is well known per se to the skilled person and will not be further detailed. Since the gas must not pass through the shutters  18 ,  12  and  24 / 28 , they should not be manipulated and the passage remains closed. 
     In case the operation of releasing the preload of the spring  32  would not have taken place before refilling of the bottle, only the shutter  24 ,  28  for residual pressure is closed, the other two  18  and  12  being open. When the pressure in the bottle increases as it is refilled, the force resulting from the pressure on the piston surface  22  bounded by the seal  28  is not sufficient to move the piston  22 . Indeed, the diameter of the torus or ring formed by the seal  28  is substantially lower than that of the piston  22  itself. The surface on which the hydraulic pressure is applied resulting in a force opposite to the spring  32  is then particularly lower than the surface of the hydraulic piston  22  since these surfaces are proportional to the square of the diameter (or radius). 
     It is then necessary to manipulate the wheel  36  to release the preload of the spring  32  and allow the return movement of the piston  22 . The residual pressure valve will then open and, at the same time, the shutters  18  and  12  will close. 
     When one wishes to activate the control device, it is sufficient to operate the wheel to preload the spring  32 . The shutters  18  and  12  will then be opened and the gas can flow into the control chamber  26 . As previously mentioned, it is only when the pressure upstream of the device  2 , that is to say, the pressure in the bottle to which the control device  2  is connected falls below a predetermined pressure that the shutter  24 ,  28  for residual pressure closes. This pressure essentially corresponds to the working pressure range in the control chamber  26 . 
     In the description of the various embodiments of the invention which has just been made, the shut-off device of the pressure regulator is of the double shutters type. However, it is understood that the invention is also applicable to a control device provided with another shutter, in particular as a simple shutter. 
     Also in the description of the various embodiments of the invention which has just been made, the movable element of the pressure reducer is a piston of a particular geometry. However, it is understood that it can take other forms. The movable element of the regulator can further comprise a metal bellows sealing with the body for delimiting the control chamber. 
     Also in the description of the various embodiments of the invention which has just been made, the connection between the piston and the shutter is a rigid mechanical connection. However, it can present some degree of freedom as a mechanical connection allowing limited relative movement between the two.