US3640241A

US3640241A - Warning device for cylinders for liquefied gas under pressure

Info

Publication number: US3640241A
Application number: US812260A
Authority: US
Inventors: Marie Francoise Adaglio
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-12-29
Filing date: 1969-04-01
Publication date: 1972-02-08
Anticipated expiration: 1989-02-08
Also published as: NL135197C; BR6905973D0; FR94226E; FR91508E; BE727495R; FR91619E; GB1202918A; FR92334E; ES346929A1; NL6901429A; GB1230025A; FR94171E; NL6715153A; LU54804A1; LU57848A1; FR91809E; DE1904881A1; CH479864A; BE706331A; FR91806E

Abstract

A warning device for a cylinder of liquefied gas under pressure for indicating to the operator when the level of gas in the cylinder is getting low, having a sleeve supported in the interior of the cylinder by a coupling connected to the tap of the cylinder and through which gas flows from the cylinder and which is closed off when the liquid falls below a predetermined level so that the consequent drop in pressure in the chamber sets a valve member into oscillation establishing a warning signal.

Description

United States Patent 1151 3,640,241 Adaglio Feb. 8, 1972 [54] WARNING DEVICE FOR CYLINDERS 424,031 3/1 890 Spencer .....137/213 FOR LI FI D GAS U D 1,723,173 8/1929 Huggins ..73/309 PREsSlgu-J 2,118,311 5/1938 j Kinderman.. .....137/214 2,510,098 6/1950 2 Geisler ..137/202 X [72] Inventor: Marie-Francoise Adaglio, 31 rue des Deux 2,895,504 7/1959 LedFrer 16/70 X poms, Paris 4 mm, prance 3,024,760 3/ 1962 13111100 ..1 16/ 109 3,073,333 1/1963 Cherrington ..137/557 X [22] Filed: Apr. 1, 1969 Primary ExaminerLouis R. Prince [211 App! 812,260 Assistant Examiner-DanielM, Yasich Related u.s. Application Data Attorney-Young & Thompson [63] Continuation-impart of Ser. No. 680,821, Nov. 6, 57 ABSTRACT 6 v A warning device for a cylinder of liquefied gas under pressure for indicating to the operator when the level of gas in the [30] Foreign Apphcaflon Priority Data cylinder is getting low, having a sleeve supported in the interi- Dec. 29, 1966 France ..89,270 or of the cylinder by a coupling connected to the tap of the May 17, 1967 France... ....l06,656 cylinder and through which gas flows from the cylinder and July 7, 1967 France ..1 13,291 w i h i closed off when the liquid falls below a predetermined level so that the consequent drop in pressure in the 52 U.S.Cl ..1l6/l09, 116/70 chamber sets a valve member into Oscillation establishing a 51 1111, C1. ..c01r23/00 Warningsisnal- [58] FieldofSearch ..116/112, 70, 109; 137/213, 1

[56] References Cited UNITED STATES PATENTS 80,328 7/1868 Berryman ..137/213 WARNING DEVICE FOR CYLINDERS FOR LIQUEFIED GAS UNDER PRESSURE This application is a continuation-in-part of my copending application, Ser. No. 680,821 filed Nov. 6, 1967.

The invention relates to a warning device adapted to be installed in a cylinder for liquefied gas under pressure for the purpose of signalling, in the course of the withdrawal of the gas, the moment when the liquid reaches a certain level, which can for instance be that when the cylinder is almost empty.

The invention provides a warning device for use in a cylinder containing liquefied gas under pressure for emitting a warning signal when liquid in the cylinder falls to a predeter' mined level, said device comprising wall means defining a chamber having a gas inlet and ages outlet, means for connecting the outlet to a gas release passage of the cylinder, the inlet being adapted to open when a part of the device is immersed in liquid in the cylinder and to close when the liquid falls to a level at least partially exposing said part of device, and valve means for controlling communication between said cylinder and said chamber after the inlet has closed comprising means in the chamber wall defining a valve seat and a reciprocable valve element responsive to pressure fluctuation in the chamber after the inlet has closed to oscillate bodily into and out of sealing engagement with said seat to emit said signal.

The invention will now be described as applied to various embodiments of the warning device of the invention, and with reference to the accompanying drawings, which are given by way of example only and in no restrictive sense.

FIG. 1 is a view in longitudinal section of the warning device of the invention, with fixed internal chamber.

FIG. 2 is a longitudinal half-section and half-elevation of another embodiment of the warning device of the invention.

FIG. 3 is a cross section through the internal chamber of the device of FIG. 2.

FIG. 4 is a view similar to that of FIG. 2 of a third embodi ment of the invention, with mobile internal chamber.

FIG. 5 is a vertical section along the line V-V of FIG. 4.

FIG. 6 is a longitudinal section of a variation of the coupling of the warning device of FIG. 4.

FIG. 7 is a section along the line VH-VII of FIG. 6.

FIG. 8 is a view in longitudinal section of a modified arrangement of the embodiment shown in FIG. 1.

FIG. 9 is a fragmentary cross-sectional view taken on the line IX--IX of FIG. 8.

FIG. 10 is a vertical section through a device according to still another embodiment of the invention.

FIG. 11 is a vertical section through a device according to a further embodiment'of the invention.

FIG. 12 is a vertical section through a device according to still another embodiment of the invention.

FIG. 13 is a vertical section through a device according to a further embodiment of the invention.

FIG. 14 is a vertical section through a further device according to the invention.

FIG. 15 shows a variation of the device of FIG. 14 in which the sleeve rests on the valve instead of vice versa.

FIG. 16 is a vertical section through yet another device according to the invention. I

FIG. 17 is a vertical section through a further device according to the invention.

FIG. 18 shows a cover for the warning device of FIG. 17 seen from below.

FIG. 19 is an axial section through a flow restricting valve.

FIG. 20 is a vertical section of a still further embodiment of the warning device.

FIG. 21 is a vertical section of another embodiment of a warning device.

The warning device as illustrated in FIG. 1 is installed in the interior of a cylinder 1 by coupling with the upper tap 2 which closes by means of a screw valve 3 and is screwed on the said cylinder by its

mouthpiece

4, 5 is the discharge nozzle.

The device forming the object of the invention has a sleeve 6-which defines a chamber and whose upper portion has a central orifice 8 extended by means of a hollow coupling 9 screwed in the interior of the mouthpiece 4 of the tap 2 and supporting the sleeve 6 in the interior of the cylinder. This sleeve'6 carries at its upper portion an orifice 10 which is adapted to be obturated by a sphere 11 forming a flap valve.

The base of the sleeve 6 has an orifice 12 which can be obturated by a second flap valve 14 which constitutes the waming device whose functioning will be explained below.

The first flap valve 1 l is connected by a rod 15 to a level 16 articulated to a ball-and-socket joint 17 which is mounted on the stem of a screw 18 passing through an opening 19 in the lever 16 and screwed in the upper wall of the sleeve 6.

A weight 21 is attached by means of rod 20 to one end of the said lever, said weight descending to a slight distance from the bottom of the cylinder and normally completely immersed in the liquefied gas.

A counterweight 24 is attached by means of rod 23 to the other end of the lever 16. The said counterweight is arranged to exerton the lever 16 a couple which is greater than that which the weight 21 exerts, in the contrary direction, when the latter iscompletely immersed and is subjected to an upward thrust called Archimedes thrust" equal to the weight of the volume of liquid displaced, but less than that which the said weight exerts in the absence of the Archimedes thrust.

Thelower flap valve 14 has a hemispherical cup 25 which under the influence of the weight of the flap valve rests on the edge of the lower orifice 12 which forms a valve seat. This flap valve 14 is extended by means of a pipe 26 opening out at its upper portion into a central orifice of the bottom of the cup 25, and, at its lower portion, into a bell 28 having lateral openings 30.

It is accordingly possible for the pipe 26 to ensure communication between the interior of the cylinder and the interior of sleeve 6. However, the upper opening of the bell 28 is normally obturated by a valve whose flap 31, here constituted of a sphere, is applied against its seat by a spring 32 supported on the bottom 33 of the bell 28.

The said valve 31 does not play any special role in the functioning of the warning device itself, and is principally intended to permit the filling of the cylinder with liquefied gas through its upper opening, by virtue of the pressure exerted by the entering liquefied gas on the upper surface of the sphere 31. This pressure opens valve 31 against the action of spring 32.

Preferably, the upper face of the bell 28 is spherical, as shown at 28a, and, by sliding upwardly, can apply itself underneath the bottom of the chamber sleeve 6, obturating the orifice'l2. Under these conditions, if, as the result of faulty operating, the noule 5 is put into direct communication with the atmosphere, the face 28a of the bell applies itself on the orifice 12, forming a check valve and preventing the gas under high pressure contained in the cylinder 1 from flowing out. If desired, a groove 28b can be provided in the said upper face 280 to allow a limited flow of gas to take place notwithstandmg.

The functioning of the warning device which has just been described is as follows: when the cylinder is full, eind while it contains sufficient liquefied gas to ensure the at least partial immersion of the weight 21, the counterweight 24 has a predominant action and, by the rocking of the lever 16, effects the opening of the upper flap valve 11. The gas under pressure located above the liquefied gas in the interior of the cylinder escapesby passing through the conduit 10 and the orifice 8 towards the discharge nozzle 5.

When the level of the liquefied gas drops, the weight 21 is progressively exposed, and the latter, subjected to less and less Archimedes thrust, becomes predominant at a certain moment in relation to the action of the counterweight 24, andthis brings about the closing of the flap valve 11. However, the gas under pressure contained in the sleeve 6 continues to escape, so that the pressure in the interior of the latter falls rapidly, and atthe moment when it becomes less than the internal pressure of the cylinder the lower flap valve 14 temporarily raises itself; the pressure equilibrium which results brings about a fresh closing of the flap valve 14.

The phenomenon is repeated at intervals, resulting in clacks of the flap valve 14 on its seat, said clacks constituting the sound warning indicating to the operator that the level of the liquefied gas in the cylinder has fallen.

The value of the counterweight and the length of the rod 20 are regulated in such a way that the sound warning is given for a predetermined level of liquefied gas in the cylinder, the said level being calculated for instance in such a way as to permit the completion of an operation of short duration which is taking place, after which the operator will have to replace the cylinder in use by a full one.

The device illustrated in FIG. 2 has an internal chamber 36 defined by a sleeve 36A which is secured to an annular member 37; the central opening 38 of this member is axially aligned with a hollow coupling 39 which is screwed into the mouthpiece of the tap of the cylinder, as in the preceding case.

This hollow fixing coupling 39 is pierced towards its base by orifices 40 bounded by a circular flange 42 which is separated from the wall 36A of the internal sleeve 36 by means of an annular orifice 44 which constitutes the upper orifice of the internal sleeve 36.

The sleeve 36A has at its base a central orifice 45 whose edges form the seat for a spherical flap valve 46 loaded by a tail 47, or for a flap valve identical to that illustrated at 14 in FIG. 1, or for a flat flap valve. The flap valve can have at its upper portion an axial extension 49 which ensures the guiding of the flap and whose section is preferably a triangle or a square with externally concave faces, in order to reduce the pressure drops. The internal chamber 36 is covered by a cylindrical jacket 48 in the form of a bell, whose base 50 is pierced axially by the coupling 39, along which jacket 48 can slide. The said jacket has lateral openings 51 in its upper portion.

In the interior of the said base 50 a resilient ring 52 is mounted, which forms an upper flap valve by covering the top of the annular orifice 44.

On the cylindrical jacket 48 there is exerted on the one hand the action of a weight, connected to the said jacket by means of rod 54, the said weight immersing in the liquefied gas, and on the other hand the opposing action of a helicoidal spring 55 bearing at its lower portion on a shoulder 56 pro vided on the exterior of the wall of the chamber 36 and, at its upper portion, on the joint 52 provided in the base 50 of the cylindrical jacket 48.

FIG. 3 is a cross section of the lower portion of the lateral wall 36A of the internal sleeve 36.

It can be seen that the said lateral wall has at this place hollows 58 which increase the passage section of the gas, whereas the remaining part of the wall ensures good guiding for the sphere 48 which forms a flap valve.

The functioning of the warning device of FIG. 2 is the same as that of the device of FIG. 1. 7

Normally, when the immersion of the weight (not illustrated) is complete, the opposing spring 55 predominates, and by lifting the cylindrical jacket 48 opens the flap valve 52 which exposes the annular orifice 44 through which the gas escapes towards the tap of the cylinder, passing through the lateral orifices 40.

When the weight is only partially immersed in the liquid, the obturating sphere 46 of the lower flap valve causes warning clacks, in accordance with the process described above.

Moreover, if the nozzle communicates directly with the atmosphere, the sphere 46 applies itself onto the annular diaphragm 37, which preferably has a projecting flange 37a forming a flap valve seat, which arrests the discharge of the gas.

In the embodiment shown in FIGS. 4 and 5 the sleeve 60 is movable.

The said sleeve is supported in the interior of the cylinder by the hollow coupling 61 which is screwed by means of its external screw-threaded portion 61A into the mouthpiece of the tap of the cylinder, by the same method of fixing as that shown in FIG. 1.

However, the said hollow coupling 61 has at its lower portion an enlargement 62 or toric or spherical surface, whose base has a circular channel 63. The lateral wall 64 of the sleeve 60 has at its upper portion an internal flange 65 which forms a flap valve, by resting on the toric surface 62 of the coupling 61, which constitutes the seat of this flap valve.

The lateral wall 64 of the sleeve 60 is closed at its lower portion, for instance by being mounted on an annular plug 67, extended at its lower portion by a pipe 68 whose base is closed by a small plate 69 and whose lateral walls have gaps or orifices 70.

The central orifice 71 of the annular plug 67 can be obturated by a spherical flap valve 72 pressed onto its seat by a helicoidal spring 73 which rests on the small obturating plate 69. This flap valve opens against the action of spring 73 during the filling of the cylinder, in accordance with the process described with reference to the embodiment of FIG. I.

The small plate 69 is pierced at its center by a central orifice in which is imprisoned with play the loop of a supple wire or thread extending towards the bottom of the cylinder with two strands 74, to the end of which strands an oblong weight 75 is attached in horizontal arrangement. For manufacturing reasons, the said weight is preferably of the ribbed type illustrated in cross section in FIG. 5.

The movable sleeve 60 constituted as described above is accordingly subjected to vertical traction from the top downwardly, due to the weight relieved by the Archimedes thrust of the liquid, which normally covers it entirely.

On the other hand, the movable sleeve 60 is subjected to the opposing action of a helicoidal spring 76 housed in the interior of its upper portion and resting on the one hand on the base of the coupling 61 by inserting itself in its circular channel 63, and on the other hand on the base 60A of the sleeve 60.

The functioning of this device will be clear from that of the devices previously described.

When the weight 75 is completely immersed in the liquid and by reason of this fact is relieved by Archimedes thrust, the opposing spring 76 has predominant action and opens the flap valve 65 by raising the movable sleeve 60 which slides on the coupling 61.

The gas escapes through the central orifice of the coupling after passing between the lateral wall 64 of the sleeve and the base of the toric seat 62 of the coupling 61.

With progressively less immersion of the weight 75, its action becomes predominating, and the movable chamber is lowered so that it occupies the position shown in FIG. 4, closing the flap valve 65.

The drop in pressure downstream which then occurs again brings about the raising of the movable sleeve 60, the renewal of the process causing warning clacks to be sounded from the flap valve 65, which then plays alternatively the role of control valve and of warning valve.

In this case also, if the noule 5 is put in direct communication with the atmosphere, the annular plug 67 rises again and its upper face 77 applies itself under the base of the coupling 61, preventing the discharge of gas. Ifdesired, a groove can be provided in this upper face to pemiit a restricted discharge of gas notwithstanding.

A variation of the fixing coupling shown at 81 in FIGS. 6 and 7 has at the base of its screw-threaded portion 82 a shoulder 83 on which rests a small elastic collar 84 in the form of a conical skirt, whose lower edge 85 is tapered.

At the level of the toric seat 86 the coupling has a thin transverse partition 87 whose lower extension 88 extends below the lower level of the base of the coupling 81. The small elastic collar 84 plays a number of roles:

I. As its upper portion is clamped to the mounting between the shoulder 83 and the mouthpiece of the tap of the cylinder, said upper portion forms a sealing joint.

2. The tapered edge 85 of the skirt fonns a screen for the slight annular opening necessitated by the sliding of this chamber on the coupling 81.

The plug 67 has an internal channel 89 and the internal extension 88 of the partition 87 has insufficient length for it to come into contact with the spherical flap valve 72 when the plug 67 is applied against the coupling 61.

When it is desired to empty the cylinder of the liquefied gas which it contains, one turns it upside down in such a way that the coupling 61 is directed downwardly, at an angle of inclination of approximately 45. The extension 88 of the partition 87 then engages in the channel 89 and thus prevents the upper face 77 of the diaphragm 67 from resting on the base of the coupling 61.

This arrangement could be applied to the embodiment of FIG. 1, the channel being provided at the base of the coupling 9 whereas the partition is provided in the cup and projects upwardly in relation to the latter.

FIGS. 8 and 9 show a warning device which is very like that of FIG. 1. Here again, there is the hemispherical cup which rests for instance on the edge of the lower orifice 12 formed at the bottom of the sleeve 6. A calibrating spring 90 is, however, provided, which rests on the base of the hollow coupling 9 and which tends to press the cup onto its seat; this spring has moreover the advantage that it increases stability and accordingly gives improved percussion.

Thecup 25 has moreover a median partition 25a which extends upwardly in a rod 25b. The hollow coupling 9 has at its lowerportion, a shoulder 91 on which the rod 25b abuts when the cylinder is upended at an angle to facilitate emptying. The cup 25 has a shoulder 25c which forms a flow restrictor by coming into abutment against the bottom of the hollow coupling 9.

FIG. 10 shows the calibration spring 90 assembled on a warning flap valve similar to that shown in FIG. 2.

In the embodiment of FIG. 11, the warning device comprises a sleeve 92 having at its bottom an orifice 93 in a shoulder 9a of the coupling 9; this sleeve 92 contains a second sleeve 94 which is sealingly attached to the lower portion of this coupling and similarly has an orifice 95 at its base. The sleeve 92 can have internal centering vanes, which are not shown; these vanes could also be fixed on the external face of the chamber 94. The coupling 9 is pierced by lateral orifices 96 which put it into communication with the interior of the sleeve 92. The two

orifices

93 and 95 are constructed in such a way as to be able to be obturated simultaneously by a spherical flap valve 97 loaded by a spring 98.

At the bottom of the sleeve 92 a support 99, provided with lateral openings 100 and a lower opening 101, is fixed. Through this latter opening the rod 102 of a flap valve 103 passes, said flap valve being urged by a spring 104 towards the opening 93, in order to close it; the rod 102 projects beyond the flap valve 103. The weight 21, which is not shown, is attached to the lower portion of the rod 102.

During filling, the fluid entering through the coupling 9 reaches the sleeve 92 through the orifices 96 and raises the flap valve 97, releasing the opening 93.

When the cylinder still contains a substantial amount of liquefied gas, the action of the spring 104 is predominating, and the rod 102 thrusts the flap valve 97 back, with the result that the latter cannot flap; the spring is disposed in such a way that the flap valve 103 does not then obturate the orifice 93.

When the cylinder is almost empty, the rod 102 is lowered and takes up the position shown in the drawing, with the result that the flap valve 97 begins to flap.

If for some reason the coupling 9 is directly connected to the atmosphere, the flap valve 103 applies itself under the orifree 93, under the influence of the vacuum prevailing in the sleeve 92, and limits the flow. On emptying the cylinder, the

rod 102 is located crosswise, with the result that the flap 103 cannot obturate the orifice 93.

The embodiment of FIG. 12 is a variation of that of FIG. 11, in which the sleeve 94 has been omitted and in which the flap valve 97 has been replaced by a flap valve substantially similar to that shown in FIG. 1, or to FIG. 8, the spring 32 resting on the bottom of a tube 105 which has lateral openings 106 and is attached underneath the cup 25.

The upper end of the rod 102 penetrates into the base of a cavity formed in the bottom of the tube 105, and forms a box 107, the bottom of which rests on a spring 108 abutting against the bottom of the support 99.

When the cylinder still contains a substantial amount of liquefied gas, the box 107 is thrust back by the spring 108 and rests against the tube to keep the cup 25 spaced from its seat.

On the other hand, when the cylinder is almost empty, the cup 25 can rest on its seat and begin to flap.

The embodiment of FIG. 13 is based on the same principle as that of FIG. 4 but the mounting is the reverse, in the sense that the flap valve which serves simultaneously for control and for warning, is located in the low-pressure line instead of in the high-pressure line.

The sleeve 110 is stationary and is located at the lower portion of the coupling 61. A tube 111 is freely mounted in this sleeve, the upper end of this tube carrying externally a flap valve 112 tending to rest on a seat 113 attached to the lower portion of the sleeve 110. A counter spring 114 is interposed between the upper end of the tube 111 and the bottom of the sleeve 110.

A box 115 is screwed to the lower end of the tube 111, said box having an orifice 116 and accommodating a spring 117 which keeps a spherical flap valve 118 applied against the end of the tube 111; this flap valve serves in the filling operation, as described above.

The mobile weight is connected to the lower part of the box 1 15, for instance by one or several flexible wires.

In the embodiment of FIG. 14, two

mobile weights

119 and 120 are fixed to the end of two arms 102 of substantially equal length arranged substantially symmetrically to the vertical. Weight 119 has little mass and considerable volume whereas weight 120 has considerable mass and little volume. The unit as a whole is fixed to a spherical flap valve 121 which can rest on a dropped edge 12 forming the seat of the valve, of a sleeve 123 which is in communication with the screwthreaded coupling. The flap valve 121 has an opening 124 extending throughout its length, on one portion of its periphery.

In normal functioning, i.e., when the

weights

119 and 120 are immersed in the liquid, the unit formed by the flap valve and the mobile weight rocks, as indicated by the arrow 125, with the result that the opening 124 puts the cylinder in communication with the screw-threaded coupling.

On the other hand, when the liquid is at the bottom of the cylinder, the unit takes up the position shown in the drawing, and the opening 124 is located beyond the seat of the valve, with the result that the valve begins to clack.

Of course, the mobile weight could be fixed to the seat 122, the flap valve 121 being stationary, as is shown in FIG. 8.

Instead of being fixed to the flap valve or to its seat, the unit of mobile weights could also control this flap valve or this seat by means of a cam. In a variation as is shown in MG. 21, the arms of the support 109 could be pivotably mounted on an axle 154 which is integral with the sleeve 123, the upper end of these arms forming a loop engaged in a cavity 155 provided at the base of the flap valve 121.

The embodiment of FIG. 16 is based on the same principle as that of FIG. 13, and here again there is the sleeve 110 and the flap valve 112 tending to apply itself against a seat 113 which integral with the sleeve 110. Here, however, the flap valve 112 is spherical and is attached directly to the semirigid rod 23 which carries the weight 24.

The calibrating spring 114 is interposed between the bottom of the sleeve 110 and a cup 126 attached to the rod 23. The fixing coupling 61 is extended, in the interior of the sleeve 110, by a collar 127 in which the flap valve 112 is located.

The wall which closes the bottom of the sleeve 110 is moreover pierced by two

orifices

128 and 129, tending to be obturated by two

flap valves

130 and 131, for instance spherical flapvalves, carried by an annular support 132 which itself rests on a spring 133 held at its base by turned over feet 134 which are integral with the sleeve 110. A flap valve 135 is attached to the rod 23 in the interior of the sleeve 110.

This embodiment functions in the same way as that of FIG. 13. The

flap valves

130 and 131 constitute the filling flap valves and the flap valve 135 a flow restricting flap valve.

In the embodiment of FIGS. 17 and 18, the warning flap valve 136 is hollow, and is extended towards the bottom of the cylinder by a tube 137 filled partially or entirely with a fibrous material 138. The tube 137 passes through the flap valve 136 and has at its upper end a stopper 139, the upper, turned over edge of which forms a cover 140 having a series of gaps 141 for the purpose of giving it great cross elasticity. The fibrous material 138 passes through the orifices 142 provided in the tube 137 so as to fill also the space defined by the cover 140 above the flap valve 136. Externally projecting portions 143 at the base of the cover 140 serve as support for the calibrating spring 90.

The two

sleeves

110 and 127, as has already been described, permit filling and emptying of the cylinder to take place by the lifting of the flap valve 136. When the tube 137 immerses itself in the liquid, the liquid rises by capillary action or wick effect up to the level of the flap valve 136, where it brings about an increase in volume of the fibrous material located under the cover 140; the said cover expands, and its projecting parts 143 come into abutment against the internal wall of the chamber 127. The clacking of the flap valve 136 is accordingly braked, and is eliminated.

On the other hand, when the tube 137 is no longer immersed in the liquid, the remaining liquid still present under the cover 140 tends to rise again and to evaporate, which brings about a decrease in the volume of the fibrous material, and consequently, a tightening of the elastic cover 140, which thus frees the flap valve 136.

FIG. 19 shows an embodiment of the flow rate restricting flap valve applicable to the embodiment of FIG. 17, in which the said annular restricting flap valve 144 rests on a stop 145 attached to the tube 137. The flap valve 136 has a lower extension 146, of such length that its end is at the same level as that of the lower edge of the orifice 147 provided in the sleeve 110 when the flap valve 136' comes into abutment against the fixing cap 61. In flow restricting position, the mobile flap valve 144 leaves its stop 145 and simultaneously applies itself against the extension 146 and the edge of the orifice 147.

In the embodiment of FIG. 20, the warning device comprises a flap valve 148 which normally rests on a seat 149 constituted by an offset edge of a sleeve 150 which is in communication with the screw-threaded coupling 61. This flap valve has an axial bore 151 which can be obturated at its upper portion by a flap valve 152 to which the rod 23 is attached.

A spring 153 tends to keep the flap valve 152 in its open position.

When the cylinder contains liquid, the spring 153 is preponderant, the flap valve 152 is open, and the gas can escape through the bore 151. On the other hand, when the cylinder is almost empty, the weight 24 is preponderant, and the flap valve 152 is applied against its seat; the flap valve 148 begins to clack.

The embodiment of FIG. 21 functions the same way as that of FIG. 14. The

weights

119 and 120 are supported from a support 155 which is attached to the bottom of the flap valve 121 and are twisted around a tie member 154.

Of course the invention should not be considered as being restricted to the embodiments described and illustrated, and it covers all variations within the spirit and scope thereof as defined in the appended clairrs.

The warning device in accordance with the invention has the advantage of simplicity together with the possibility of various embodiments allowing application to the most various cases. Its usefulness is great, since by its use, the operator of liquid fuel cylinders is not longer under the serious disadvantage of encountering a sudden, unexpected and final stoppage of the flow of gas resulting from the using up of the supply of gas in liquid phase.

What I claim is:

1. In a warning device for the level of liquid in containers of liquefied gas under pressure, including a connecting coupling having a passageway therethrough for the escape of gas from the container, the couplin havin a seat thereon within the container on which a mem er res by gravity and which can rise and fall repeatedly upon the seat to give a warning sound when the liquid level in the container is below a predetermined minimum; the improvement in which said member includes a portion that extends downwardly below said seat in the form of a tube at least partially filled with a fibrous material forming a wick, said member including fibrous material within said coupling and that receives liquid from the wick and that when moist expands against an internal wall of the coupling to retard vertical movement of said member.

2. A device as claimed in claim 1, and an annular flowrestricting valve surrounding said downwardly extending por' tion of said member and resting by gravity on a stop on the member and freely vertically movable relative to said stop.

3. In a warning device for the level of liquid in containers of liquefied gas under pressure, including a connecting coupling having a passageway therethrough for the escape of gas from the container, the coupling having a seat thereon within the container on which a member rests by gravity and which can rise and fall repeatedly to give a warning sound when the liquid level in the container is below a predetermined minimum, and weight means supported by said coupling and having a density greater than the density of the liquid in the container and disposed adjacent the bottom of the container, said member being urged by the weight means to close the passageway to the flow of gas therethrough, and means acting on said closing means upwardly against the weight with a force which is greater than the downward force exerted by the weight means when the weight is fully immersed in the liquid in the container but less than the downward force exerted by the weight means when the weight at least partly emerges from the liquid in the container; the improvement in which the weight means comprises two weights that are asymmetric about a vertical plane so that the two weights occupy different horizontally swung positions when fully immersed in liquid and when at least partially emergent from the liquid, said member having an opening therethrough which is exposed during the horizontally swung position of the immersed weight means but not exposed during the horizontally swung position of the at least partially emergent weight means.

4. In a warning device for the level of liquid in containers of liquefied gas under pressure, including a connecting coupling having a passageway therethrough for the escape of gas from the container, a sleeve attached to said coupling and having a chamber therein, said chamber having a seat thereon at a lower portion thereof on which a member rests by gravity and which can rise and fall repeatedly to give a warning sound when the liquid level in the container is below a predetermined minimum, a weight supported by said coupling and having a density greater than the density of the liquid in the container and disposed adjacent the bottom of the container, the improvement comprising a support fixed to the lower part of the coupling, a rod mounted for vertical sliding movement in the support, said weight being carried by the lower part of the rod, and a spring acting upwardly on the rod between the rod and the support with a force sufiicient to engage said rod with said member and raise said member from said seat when the weight is fully immersed in the liquid in the container but insufficient to raise said member from said seat when the weight at least partially emerges from the liquid in the container.

5. A device as claimed in claim 4, and a spring acting between said member and an upper portion of said chamber to urge said member downwardly to close the passageway.

Claims

1. In a warning device for the level of liquid in containers of liquefied gas under pressure, including a connecting coupling having a passageway therethrough for the escape of gas from the container, the coupling having a seat thereon within the container on which a member rests by gravity and which can rise and fall repeatedly upon the seat to give a warning sound when the liquid level in the container is below a predetermined minimum; the improvement in which said member includes a portion that extends downwardly below said seat in the form of a tube at least partially filled with a fibrous material forming a wick, said member including fibrous material within said coupling and that receives liquid from the wick and that when moist expands against an internal wall of the coupling to retard vertical movement of said member.

2. A device as claimed in claim 1, and an annular flow-restricting valve surrounding said downwardly extending portion of said member and resting by gravity on a stop on the member and freely vertically movable relative to said stop.

4. In a warning device for the level of liquid in containers of liquefied gas under pressure, including a connecting coupling having a passageway therethrough for the escape of gas from the container, a sleeve attached to said coupling and having a chamber therein, said chamber having a seat thereon at a lower portion thereof on which a member rests by gravity and which can rise and fall repeatedly to give a warning sound when the liquid level in the container is below a predetermined minimum, a weight supported by said coupling and having a density greater than the density of the liquid in the container and disposed adjacent the bottom of the container; the improvement comprising a support fixed to the lower part of the coupling, a rod mounted for vertical sliding movement in the support, said weight being carried by the lower part of the rod, and a spring acting upwardly on the rod between the rod and the support with a force sufficient to engage said rod with said member and raise said member from said seat when the weight is fully immersed in the liquid in the container but insufficient to raise said member from said seat when the weight at least partially emerges from the liquid in the container.