Improved pressure adjusting device for controlling the liquid gas flow rate

Abstract: The present invention relates to an improved pressure adjusting device for controlling the flow rate of liquid gases, which comprises a body (1) consisting of a top half shell (3) and a bottom half shell (2), coupled to one another through the interposition of a resilient membrane (4) which defines a gas pressure control chamber (6) and a gas pressure reducing and delivery chamber (5), communicating with a gas de­ livery outlet. The bottom half shell (2) defines a cylindrical end piece (7) which can be coupled to the valve (8) of the gas pressure vessel (9). The main feature of the invention is that there are provided quick coupling means (10), opera­ ting between the end piece (7) and the valve (8), which are adapted to operatively engage with the operating knob (13) of the valve means of the adjust­ ing device for preventing the adjusting device from improperly engaging with or disengaging from the gas pressure vessel (9) as the mentioned valve means are in their opening position.

Description: BACKGROUND OF THE INVENTION The present invention relates to an improved pressure adjusting device for controlling the flow rate of liquid gases. As is known,on liquid petroleum gas pressure vessels or bottles there are usually mounted pressure adjusting devices adapted to control or adjust the pressure of the gas outflow. Conventional gas flow rate adjusting devices comprise a resilient membrane which divides the inside of the pressure adjusting device into a pressure reducing and delivery chamber and a control chamber, which communicates with the atmosphere pressure and therein there are housed resilient means. Depending on the outlet gas flow rate,said resilient membrane is deformed in both directions so as to adjust the gas outflow. The presently known pressure adjusting devices, however,are affected by the drawback that the gas outflow can be hardly shut off in the case of a leak caused,for example,by a breakage of the resilient membrane or outer gas delivery hose,or of a leak through the pressure adjusting device or in the gas supplying system downstream of said pressure adjusting device. Another drawback of known gas pressure adjusting devices is that they may be erroneously coupled to the gas bottles by the user,with consequent gas leaks. The document FR-A-2 050 851 discloses a pressure adjusting device having substantially the features of the pre-characterizing portion of the main claim. SUMMARY OF THE INVENTION Accordingly, the main object of the present invention is to overcome the above mentioned drawbacks, by providing an improved pressure adjusting device which can be properly coupled to the gas bottle, exclusively as the gas flow shut off means of said bottle are safely closed. Another object of the present invention is to provide such a pressure adjusting device which is adapted to accurately control the gas flow rate, while automatically shutting off the gas flow in a case of an excessive flow rate. Another object of the present invention is to provide a pressure adjusting device adapted to automatically shut off the gas flow as gas leaks occur through the pressure adjusting device or in the downstream gas system. Still another object of the present invention is to provide a pressure adjusting device which is very reliable and safe in operation. Still another object of the present invention is to provide a pressure adjusting device which can be easily constructed starting from easily available materials and components and which,moreover,is very competitive from a mere economic standpoint. According to one aspect of the present invention,the above mentioned objects,as well as yet other objects, which will become more apparent hereinafter, are achieved by an improved pressure adjusting device having the features of the characterizing portion of the main claim. for controlling the flow rate of liquid gases, The automatic shut off of the gas flow being performed by means of a suitable lever arranged in the gas delivery chamber and adapted to lock at a closing position a gas flow adjusting piston member. BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics and advantages of the present invention will become more apparent hereinafter from the following detailed description of a preferred, though not exclusive, embodiment of a pressure adjusting device according to the invention,which is illustrated, by way of an indicative but not limitative example, in the figures of the accompanying drawings in which: figure 1 is a cross-sectional view illustrating the pressure adjusting device according to the invention, the valve means being shown in their open condition; figure 2 illustrates the pressure adjusting device of figure 1 with the valve means shown in their closed condition, and figure 3 is a cross-sectional view of the device taken sustantially along the line III-III of figure 1. DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the figures of the accompanying drawings, the improved pressure adjusting device for controlling the flow rate of liquid gas according to the present invention,comprises a body,indicated overally at the reference number 1,which substantially consists of a bottom half shell 2 thereto there is coupled a top half shell 3,with the interposition of a resilient membrane 4;this membrane 4 defines a gas delivery chamber 5 at the bottom half shell 2,and a gas control chamber 6 communicating with the atmosphere and formed inside said top half shell 3. At the lower portion of the bottom half shell 2 there is defined a cylindrical end piece 7 which can be coupled to the valve 8,which valve is usually provided on a pressure vessel or bottle,indicated overally at 9 and holding the liquid gas. A main feature of the present invention is that between the end piece 7 and valve 8,in the inside of which there is provided a gate member 8a, there are provided quick-coupling means consisting of a slider 10,counterbiassed by a spring 11,which transversely extends of the axis of the valve 8 and engages in a groove 12 formed on the valve. As is shown in fig.3, the slider 10 is provided with different size holes or openings 100, 101 on the fork member 10a,and a spring 11 is provided for holding said slider 10 engaged in the groove 12.As it should be apparent,by pressing on said slider 10 against the force of said spring 11 as indicated by the arrow, the greater diameter hole or opening 100 will be brought at said groove so as to afford disengaging. In order to prevent the pressure adjusting device from being improperly coupled,or engaged with/disengaged from the pressure vessel or bottle 9 as the valve means of the pressure adjusting device are in their open condition,the knob 13 for driving said valve means is provided with a lug 14. As shown in figure 1, this lug,in an opening condition, will be arranged on the path of the slider 10 so as to prevent this slider from sliding;in this way the pressure adjusting device can not be coupled to or detached from the gas holding pressure vessel or bottle. With the knob 13 in its closing condition, as schematically shown in figure 2,the slider will be able of freely sliding and,accordingly,the pressure adjusting device can be removed. In this connection,it should be apparent that,in a case of a not perfect coupling,the knob 13 can not be rotated from the closing position to the opening position,since,during such an operation,the lug 14 will abut against the slider 10 which has not yet reached its proper engaging position. Inside the bottom half shell 2 there is formed a gas inlet chamber 15 thereinto liquid gas is supplied in a filtered condition by passing through the gap existing between the sliding hole and the stem or shaft 16 axially arranged inside the end coupling piece 7. In said chamber 15 there is arranged a driving cam member 17 which is coupled to the knob 13 and is provided with a cam surface 18. This cam surface 18 cooperates with the top end of said stem 16 in order to cause said stem to be displaced against resilient biassing members 19 acting on said stem 16 which projects at the bottom so as to engage with the gate member 8a. At the output of the chamber 15 there is provided a nozzle 21,which communicates with the outlet 22 of the gas delivery chamber and is controlled by a sealing gasket 23 supported by a small axially sliding piston 24 which is able of axially sliding with respect to the outlet 22. The piston 24 is slidingly supported by a support 25,which is housed in an extension of the gas delivery chamber 15. On said piston 24 two levers 30 and 31 operate,which levers are articulated to the support 25 at symmetrical positions with respect to said piston and are respectively provided for adjusting and controlling the gas excess flow. More specifically,said levers 30 and 31 are coupled to the middle portion of the membrane 4, by means of a bracket 35 to the lower portion of which there is coupled the pin member 36 supporting the respective legs or arms of the levers. As is shown,the bracket 35 bears,at its opposite end,on the middle portion of the membrane 4 so as to form therewith a single body which is pressed by an adjusting spring 37 operating on a plate member 38 provided with a vertically extending arm,indicated at 39. This vertical arm projects through the window 40 which is defined through the top half shell 3. The lever 30 is provided for slidingly driving the piston 24 depending on the raising of the membrane 4,so as to adjust or control the gas flow coming from the pressure vessel. The second lever 31,in turn,operates in the reverse way by driving the piston as the membrane is arranged in its lowered position,for example because of a gas take up greater than the rated flow rate of the pressure adjusting device,such as in the case of a breakage or disengaging of the gas supply hose,or of the membrane,during the liquid gas supplying period,or in the case of small gas leaks. As is shown,in the cavity defined by the chamber 15 there is housed a small ball 32 which, as the gas flow rate is greater than the rated flow rate of the pressure adjusting device,will be entrained by the gas flow against the nozzle 21, so as to generate a greater flow loss and cause the membrane to be depressed and operate the second lever 31 so as to shut off the gas delivery by means of the piston 24. As shown an axially movable slider member 41 abuts on the adjusting spring 37 which slider member is adapted to upwardly and downwardly move, without rotating,under the control of a rotating handwheel 42 screw engaged therewith. More specifically the top end of stroke position of said slider 41 will set the minimum desired output gas pressure,the maximum gas pressure being controlled by the bottom end of stroke position of said slider as said handwheel is idly rotated. In this connection it should be pointed out that the device according to the invention will be always held in a safe condition,and it can be reset to a proper operation condition by simply manually operating the vertically extending arm 39. In fact,as said vertical arm 39 is operated, the plate member 38 will be raised so as to disengage the membrane 4 from the pressure of the spring 37, thereby raising the lever 31 and opening the nozzle 21 to allow for the liquid gas to normally flow. The manual operation for opening and closing the pressure adjusting device,and hence the gas supply,is performed by rotating the knob or handle 13,which is rigid with the eccentric shaft 17 driving said stem 16 thereon there is rigidly mounted an O-ring sealing gasket 46,which,as it is vertically displaced will open and shut off the gas passage port from the chamber 47 to the chamber 15. From the above disclosure it should be apparent that the invention fully achieves the intended objects. In particular the fact should be pointed out that the pressure adjusting device according to the invention can not be engaged to or disengaged from the pressure vessel as the valve means are in their open position,and moreover the gas supplying operation can not be started unless the device has been properly engaged. Moreover this device has a very safe operation,since the levers 30 and 31 will operate automatically for controlling the outflow of the gas or shut off it,in a case of any malfunctions.

Claims: An improved pressure adjusting device for controlling the flow rate of liquid gases, comprising a body (1) consisting of a bottom half shell (2) and a top half shell (3), which are coupled to one another through the interposition of a resilient membrane (4), said resilient membrane defining a gas pressure control chamber (6) and a gas pressure reducing and delivery chamber (5), communicating with a delivery outlet, said bottom half shell (2) defining with the gas valve (8) of the gas pressure vessel (9) a coupling end piece (7), said pressure adjusting device further comprising quick coupling means (10) operating between said coupling end piece (7) and gas valve (8), adapted to operatively engage with a knob (13) for operating valve means of the pressure adjusting device so as to prevent said pressure adjusting device from improperly engaging with and/or disengaging from said gas pressure vessel (9) as said valve means are in their open position, characterized in that said quick coupling means comprise a resilient biassed slide member (10) transversely movable of said coupling end piece (7), said slide member (10) being provided with different size openings the edges of which are adapted to be removably engaged in an annular groove (12) formed on said coupling end piece (7) so as to be arranged at an engagement position and at a disengagement position, one end of said slide member being adapted to abut against a lug (14) of said operating knob (13) as said operating knob is in its open position. A pressure adjusting device according to claim 1, characterized in that it comprises, in said delivery chamber, a first and second lever (30, 31) pivoted to a support member (25) for guiding a piston member (24) controlling a gas delivery nozzle (21), said levers including each a long arm engaging with a bracket (35) rigid with the middle portion of said resilient membrane (4) and a plate (38) provided with a side driving arm (39) projecting from said chamber, said first and second levers (30, 31) causing said piston member (24) to slide in opposite directions with respect to said resilient membrane (4). A pressure adjusting device according to claims 1 and 2, characterized in that it comprises an adjusting spring (37) acting on the middle portion of said plate (38), said adjusting spring (37) being calibrated by a slider (41) able of axially sliding so as to engage with a hand-wheel (42) rotatably supported by said top half shell (3), a top limit switch being provided for setting the minimum output pressure, and a bottom limit switch being provided for setting the maximum pressure. A pressure adjusting device according to one or more of the preceding claims, characterized in that one (30) of said levers (30, 31) is adapted to operate as a flow rate adjusting member, by driving said piston (24) as said resilient membrane (4) is raised, the other lever (31) being adapted to operate as a member for adjusting the excess flow by driving said piston as said resilient membrane (4) is lowered. A pressure adjusting device according to one or more of the preceding claims, characterized in that the pivot support (25) of said levers (30, 31) is adapted to operate as a guide member for said sliding piston (24) which is adapted to shut off said delivery nozzle (21). A pressure adjusting device according to one or more of the preceding claims, characterized in that it comprises a ball (32) arranged in the gas outflow chamber (15) and adapted to operate as a restraining member which, by generating an increase of the gas flow charge loss, causes the excess flow lever to efficiently operate so as to shut off the gas delivery as the gas flow rate is greater than the rated flow rate of said pressure adjusting device. A pressure adjusting device according to one or more of the preceding claims, characterized in that it comprises a lever for adjusting the gas excess flow said lever being also adapted to operate as a member for signalling the gas path thightness conditions downstream of said pressure adjusting device. A pressure adjusting device according to one or more of the preceding claims, characterized in that it comprises an O-ring gasket (46) mounted on a vertical stem (16) for opening and closing said valve means and adapted to operate as a gas flow shut off member even in the case of a malfunction of the valve mounted on said pressure vessel.

Inventors: LIMIROLI MARIO C O LIQUIPIBIGA, LIMIROLI, MARIO C/O LIQUIPIBIGAS S.P.A.
Applicants: LIQUIPIBIGAS S P A, LIQUIPIBIGAS S.P.A.
Application year: 1988
Main classification: F17C13
IPC codes: F16L37, F17C13