CA1053990A - Gas leak detector - Google Patents

Abstract

ABSTRACT
A gas flow detector for use in a combustible gas duct system, which comprises a transparent hollow cylinder or sleeve which is provided with an inlet and an outlet at different levels so that, when the sleeve is partially filled with a liquid, gas can be directed, from the inlet, through the liquid to the outlet without liquid exiting through the outlet. The relative position of the liquid and the inlet port can be varied so that, in one position gas flow from the inlet to the outlet passes through the liquid in the cylinder and, in another position bypasses such liquid.

Description

FIELD OF TH~ INVENTION
This inven-tion relates to a gas leak detector.
More particularly~ this invention relates to a gas detector of the type intended for insertion into a gas duct system leading from a gas source -to a gas consumption place and adap-ted when operated to indicate whe-th~r or not a leak exists in tubular duct pipes, elastic tubes, faucets or stop cocks or ignition control members in a gas duct system ~r ..
apparatus for combustible gases connected to said system. .
: THE PRIOR ART : .
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Gas leak de-tectors of the type in cons;deration comprise a check body having the shape 2f ,' or carrying.a separate, sleeve or hollow cylinder which par-tially is filled with a check fluid and which at two places separa-ted from one another i5 connected to firstly the duct portion of the system - coming from the gas source and secondly to the duct portion . .
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of the sys-tem leading to the gas consumption place. In a detèctor of this type known from the US Patent Specification :, , . . .
3,582,435, a gas leak is indicated by gas bubbles raising in the check liquid which bubbles can be observ~ed through .
a window provided in the wall of the vertically mounted sleeve . adjacent the bottom thereof. When a leak exists in the plumb- !
-~ ing~and appliance system the bubbles are developed as soon j~.
as after closing the~gas tan]c valves and shutting off all gas . appliances a plunger located at th.e upper end o~ the sleeve 1~-. is pressed.downwards and changes -the way for the gas passing~

through -the.slee~e so -that said way is through the fluid.

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This known leak detector has the disadvantage tha-t the plunger must be displaceable, in a gas-tight manner, within the check sleeve which, of necessity, re- :
quires gas-tight seals. However, these seals wear out relatively rapidly with fre~uent use of the detector, and thus in themselves constitute sources ol- possible leaks which are the more dangerous as they do not cause generation of gas bubbles in the check fluid. Another disadvantaye of the known detector is that its check window is so placed that it is difficult or even impossible to read through it in the narrow spaces which are often available for the installation of plumbing and appliances in trailers, boats, campers, summer cottages, etc.
One main object of the invention is to eliminate the disadvantages oE the prior art by providing a gas leak detector which has no moving parts, and thus eliminates the need for gas-tight seals.
Another object of the invention ls to provide a gas leak detector which is also suited for use in high 20. pressure gas systems.
Still another object of the invention is to provide a gas leak detector which can be used in narrow spaces for ~ ready observation oE gas bubbles in the check fluid indicat- :
ing that a leak exists in the gas duct system.
Thus, by one aspect of this invention there is provided a device for checking gas flow through a line, comprising:
a body having a chamber therein;
inlet and outlet means to said chamber for connect-; 30 ing said chamber~ in series, with said line Eor gas flow

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' ~'``' therethrough; said inlet and outlet means having respective ports at different elevational positions, rela~ive to each other, so that when a liquid is present in said chamber, gas enteri.ng through th~
inlet port can be direc-ted through said liquid to the outlet port without liquid flow through said out-let port; and means for varying the relative position of said liquid and said inlet port so that, in one position, gas ~low from the inlet to ~he outlet passes through the liquid in the chamber and, in another position, bypasses such liquid.
SHORT DESCRIPTION OF THE DRAWINGS
Further objects and features as well as the main advantag~s of the invention will become apparent from the following description ~ a prefqrrsd embodi-ment with refçrence . 30 ~'

- 4 -" ~1.<, , to -the accompanying drawirlgs, which form par-t of this specification, and of which:-~ ig. 1 is a longitudinal, par-tially sectional view f a gas leak de-tec-tor cons-tructed according -to -the invention and shown in inactive posi-tion.
Fig. 2 is a sec-tional view of the de-tec-tor according to the line II-II in ~ig. 1.
Fig. 3 is a similar sec-tional view as in Fig. 2 with -the check body forming part of -the detec-tor in reading posi-tion.
Fig. 4 finally shows a sec-tion following -the line IV-IV of Fig. 2.
DETAILED DESCRIPTION OF THE PREFERRE~ EMBODIMENT
Re~erring now -to -the 'drawings, a gas'leak detec-tor generally denoted 1 and embodying the main fea-tures of -the invention comprises a frame or support 2, secured by means - of fixing screws 3 onto a wall 4 of a -trailer, for example.
Fixed by means of screws S on-to -t:he support 2, which suitably has -the'shape of a backing plate~ is a half-cylindrical 2a protective cover 6 whîch encloses a resilient tube part 8 mounted on a bracke-t 7 rigidly attached -to the support ~.
I Said resilient tube part 8 is connec'-table -to a tubular duct por-tion indica-ted by arrow 13 as leading to a gas consump-tion . . . . . . .
'~ place, e.g. a gas burner not shown, by means of nuts 9 a-t the one end wall of the protective oover and a connec-ting I nipple 12 rigidly attached in -tne protec-tive cover ~6 by a ' j clip 10 and screw connection means 11. The opposite end wall of the protec-tive cover 6 lS passed by ano-ther connecting I -tube nipple 15 which is re-tained by nuts 14 so as -to 'be -turnable iD relation -to suppor-t 2 and which -through sui-table .: _ 5 _ .~ , ' ` .

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connec-tion means no-t shown here in more detail is coupled to a tUbular duct por-tion 16 coming from a gas source, e.g.
a L.P. gas bot-tle also not shown in -the drawings.
Mounted onto the other end oE the turnab~Le connecting tube nipple 15 is a check body 17 -til-table upwards from a substantially vertical inactive posi-tion (Figs. 1 and 2) into a substantially horizon-tal reading position (Fig. 3).
Said check body contains a socket 18 which in a gas proof manner is connected with the nipple 15. A check sleeve or hollow cylinder 19 is screwed on-to -the check body. This check sleeve 19 encloses a check tube 21 partially filled wi-th a check fluid 20 and made of glass or some o-ther sui-table transparent material, e.g. plastic of the kind ob-tainable in commerce under -the regis-tered trade denomination "Plexi-glas". The check fluid which is of such na-ture tha-t -the gas not at all or at leas-t no-t substantially is soluble therein, is con-tained in the check tube 21 in such a little quantity that a minor por-tion only of -the volume of the tube~ in -the il1ustra-ted embodiment one -third o:f the volume, is occupied by the fluid. The check -tube 21 is in a gas~ and liquid--tight manner moun-ted in -the check sleeve 19 by means oE upper and lower sealings 22. In order -to permit observation of -the check tube and -the check fluid con-tained therein, inspection windows or openings 23 are :Eormed in the wall of the sleeve 19. In the illustrated embodiment Eour such windows 23 are distri-buted wi-th even spacing over the wall of the sleeve 19. A gas discharge bore 25 formed in the chec]c body 17 extends from -the sleeve 19, more particularly the upper end thereof, through a connecting nipple 26 -to -the resilien-t -tube 8 connec-ted to -the gas discharge duc-t por-tion 13.

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To preven-t check Eluid from escaping ou-t of -the gas leak de-tec-tor prior -to -the moun-ting -thereof a-t -the observa--tion place, removable sealing plugs 27 are provided at -the two ends of -the detector intended for connecting the same to -the associated duct portions of the gas sys-tem.
When the gas duct system is in opera-tive posi-tion, i.e. the valve ~not shown) con-trolling -the outflow from the gas source and also at least one of the valves to the apparatus a-t the consumption place are open, -the gas flow passes through -the gas feed duct 16 and the check socke-t 18 in-to -the leak detec-tor 1 down -to the -tube 21 in -the check sleeve 19. There--upon, the gas con-tinues to flow through the gas discharge bore 25 in the check body 17, the resilien-t duct tube 8 and the connecting nipple 26 in-to the gas discharge duct 13 and ¦
further to the apparatus where the gas is consumed.
In this operative position of -the gas syste~, the check body 17 with -the sleeve 19 and the check -tube 21 take the inoperative position shown in Figs. 1 and 2, i.e. a substan--tially ver-tical posi-tion in which -the check fluid 20 fills only -the lowermos-t portion of the chec}c tube 21, which in -the embodiment is about one -third of the total volume of ~ the tube.
- The gas which streams out from the socket 18 inside -the sleeve 19 never will be in con-tact with the check ~luid 2Q, since -the level 28 thereof is loca-ted below the lowermost `;~ par-t of -the socke-t 18. The sleeve 19 a~d therewi-th also the level of the check fluid, enclosed in the check tube 2~ are always kep-t in this position when the consump~tion apparatus is being used. The resilien-t tube 8 moun-ted between the check ; 30 ~ body 17 and -the sup?or~t 2 is prestressed to such -torque force ' '~
~3 -tha-L -the sleeve 19 is forced agains-t a lower s-top 30 forrned i.n the protec-tive cover 16, see Fig. 2.
When -tes-ting whe-ther or no-t a leak exis-ts in -the gas duc-t system, -the valve from the gas source is kep-t open whereas all valves -to the gas consumption appara~tus are closed.
Now, -the check sleeve 19 of the leak detector is til-ted upwards against the pres-tress torque force existing in the - resilien-t tube part 8 towards an upper stop 29 formed on the protective cover 6. In -this posi-tion the check fluid 20 in -the tube 21 has been displaced so that it, as will be seen from Fig. 3, extends substan-tially along the lower por-~tion of the wall of said -tube. By -the upward -tilting move-men-t of the sleeve 19, the check body 17 has also been turned .
upwards together wi-th the nipple 15 and, as a consequence, -the socke-t 18 ~ixed has participated also in -this turning ..
or -til-ting movement. By -the change of position, the check fluid 20 reaches the upper portion of the check -tube 21 in-to which ~the socke-t 18 projec-ts. In order -to make sure that -the mou-th of said socket is positioned wholly below the fluid level 28, the opening end por-tion of the socket 18 has been given a .
bend direc-ted.downwards in the upwards ~tilted position of ~the sleeve 19 so -tha-t said opening end portion almos-t reaches -the wall of -the check tube 21. By -the tilting movement in upward direction of the sleeve 19, the inspection windows 23 in -the wall of said sleeve have been brought into such posi--tions -tha-t possible gas bubbles can be observed easily -through one of -tlie windows, which means from above, from below or `:
from one or the o-ther side. If bubbles are observed to rise in the check fluld, i-t is established -that a leak exis-ts a-t some place in the gas sys-tem and safety measures must be -taken.
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If no bubbles become visible, -the duc-t sys-tem is gas-tight.
When -the sleeve 19 is released, i-t re-turns a-tuo~a-tical-ly, due to the pres-tressing o:F -the resilien-t tube part 8, into its vertical inoperative posi-tion, ancl the gas sys-tem ~ ~' can be used.
MAIN ADVANTAGES OF THE INVE~TION
¦ Compared wi-th previously known cons-tructions, -the gas leak detector according to -the invention has the Following advantages:
It does not contain any movable units or parts which require gas-tigh-t sealings. For -this reason, -the leak de-tector ¦ -can be used in high pressure systems also. In known leak detectors, where movable par-ts or units are comprised which must be sealed with packings or similar means, leaks can come into existence in the detec-tor itself, which faults can not be detected or indicated by the same. In -the leak detector according to the present invention the check fluid is carried towards the check socket by a rela-tive change of the fluid level. When sealings 22 for the check -tube 21 inside -the sleeve 19 become untigh-t, gas bubbles are developed in the check fluid when the de-tector is opera-ted. Since the leak detec-tor most preferably shall be mounted as near -the gas source as possible and there~ore of-ten is placed in boxes for L.P.G. bo~ttles or other narrow spaces at disposal near the bot-tom~ it is a fur-ther advantaee that the reading can be made from above, or in other cases, when -the gas lea]c de-tec-tor has been placed immediately below a low roof such as in boa-ts, .
from below~ or from one side.

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P~INCIPI OR ANOTHER EMBODIMENr It is easily understood that -the change of -the level of -the check fluid rela-tive -the opening of -the check socket also can be brough-t about inside an immovable ver-tically mounted check sleeve by compressing a resilien-t ball connected in open communication wi-th the check -tube and wholly filled with check fluid, by which compression -the quan-tity of fluid present inside the check tube is increased so much that the level of the fluid is raised over -the opening of the socket '.

projecting into the check ~tube. In this case, the opening por-tion of the socke-t, of course, need not be given any bend towards -the wall of -the check tube.
While one more or less specific embodimen-t of the inven-tion has been shown and described, it is -to be unders-tood that -this is for purpose of illus-tra-tion only, and that -the invention is not to be limited therè~y, but its scope is to be determined by the appended clai.ms.

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Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A device for checking gas flow through a line, comprising:
a body having a chamber therein;
inlet and outlet means to said chamber for connecting said chamber, in series, with said line for gas flow therethrough; said inlet means having one single inlet port and said outlet means having one single outlet port within said chamber, so that, when a liquid is present in said chamber, gas entering through the inlet port can be directed through said liquid to the outlet port without liquid flow through said outlet port;
means for varying the position of said liquid relative to said single inlet port so that, in one position, gas flow from the inlet means to the outlet means passes through the liquid in the chamber and, in another position, bypasses such liquid; and transparent means in said chamber for permitting observation of the conditions prevailing in the liquid with respect to the appearance of the bubbles therein.

2. A device as claimed in claim 1, wherein the chamber is displace-able from a lower position into a higher one in relation to said inlet port.

3. A device as claimed in claim 1, wherein said body is tiltable from a substantially vertical inactive position, in which position the liquid is collected in the bottom portion of said body and at a level out of contact with said inlet means, to a substantially horizontal reading position, in which position the liquid surface extends to a higher level, in relation to the inlet and outlet means, along a lower wall portion of the horizontally tilted body and covers said inlet means.

4. A device as claimed in claim 3, wherein the tiltable body is connectable to the outlet means through a gas discharge bore positioned high in the body and tiltable together with said body and a tube connect-ing nipple, and to the inlet means through another tube connecting nipple and a check socket projecting into the interior of the body and rigidly attached to, and turnable with, the body and having such a length and configuration as in the inactive position of the body to have its free end opening above the level of the fluid in said body, but in the reading position below said level entirely within said fluid.

5. A device as claimed in claim 4, wherein the end opening portion of said check socket is bent towards the wall of the body in such a direction so that, in the reading position of the body, said free end opening is located adjacent the lowest portion of the socket wall.

6. A device as claimed in claim 3, wherein the inlet and outlet means include a resilient tube fixed prestressed to such torsional force that the body is forced into its vertical inactive position against a stationary stop.

7. A device as claimed in claim 3, wherein said means for varying the position of said liquid comprises a hollow compressible body connected, in open communication, to the chamber below said liquid level in said active position of said chamber, in which position said hollow body is adapted to be filled with liquid which, by compression of the body, may be forced into the chamber and thereby cause the surface of the fluid to rise to a level so as to cover the inlet port.