US2106147A - Apparatus for detecting gases - Google Patents

Description

Jan.- 18, 1938. w. K. HULL APPARATUS FOR DETECTING GASES Filed Aug. l2, 1935 2 Sheets-Sheei l HIEI William Kz'ffr Hull.

Jan. 18, 1938. W. K. HULL APPARATUS FOR DETECT'IN G GASES Filed Aug; 12, 1955 2 sheets-Sheet 2 Patented Jan. 18, 1938 UNETED STATES APPARATUS FOR DETECTING GASES William Keffer Hull, Hagerstown, Md., assignor to The Hull Manufacturing Company, Hagerstown, Md., a corporation of Maryland Application August 12, 1935, serial No. Sasse 'l Claims.

This invention relates generally to apparatus for detecting gases and is concerned more particularly with the detection of gases containing halide gases as the refrigerant in refrigerationy and air conditioning units, the problem of de tecting leaks has become of great importance. This problem is complicated because of the fact that these gases are practically odorless, tasteless and colorless and therefore dilcult to detect, especially when mixed with comparatively large quantities of air.

This invention is particularly adapted for use in detecting even traces of gases of the type just mentioned because of leakage from refrigerating units and the like and therefore, for convenience,

`this use of the invention Will be described, but it is to be understood that the invention is not limited to this particular use.

Broadly stated, the general object of the invention is to provide improved apparatus for detecting the presence of gases of the character indicated by means of the characteristic light emitted by suitable reactive material, when heated, in the presence of the gas to be detected.

Stated more specifically, one of the principal objects of the invention is to provide, as a simple, light, compact, portable, inexpensive, troubleproof unit, means for supporting and heating the reactive material under conditions which ensure maximum sensitivity in the detection of the gas to be detected, together with means for automatically creating the maximum amount vof suction for bringing the gas to be detected into proximity to or contact with the reactive material.

Another object of the invention is to provide novel means for collecting the gas to be detected, usually mixed with air.

A further object of the invention is to provide a novel burner which can be easily and conveniently adjustable and controlled and which ensures perfect combustion of the fuel.

Other objects and novel features and advantages of the invention will become apparent from the following description taken in conjunction with the following drawings which illustrate two forms of apparatus embodying the invention, it being understood that the description of these specic embodiments is merely illustrative and 55 not restrictive.

In the drawings: Fig. 1 is a perspective view of one form of apparatusV embodying the invention,

Fig. 2 is a longitudinal sectional view taken through the burner head,

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2,

Fig, 4 is a longitudinal sectional View of the gas collector tube,

Fig. 5 isa perspective View of a modified form of the invention, and

Fig. 6 is a longitudinal sectional view of the modified form.

Referring to the drawings, more particularly Figs. 1-4, I indicates generally a torch or burner, suitable for burning gaseous fuel, such as acetylene, butane, or other similar combustion gases. Burner I comprises a burner head or body 2 and a handle portion or grip 3 fitted with tubes or conduits 4 and 5 by means of which the handle is connected to the burner head 2. One end of tube 5 is connected by screw threads to a threaded socket or aperture 6 in the burner head and the other end is connected either directly or by means of a hose to a valve-controlled tank 1 or other suitable source of acetylene or similar gas under pressure. When the burner is connected directly to a tank, especially of the light portable type, the latter functions as a base or support for the burner to provide a very convenient portable self-contained unit. One end of pipe or tube 4 is connected by screw threads to a threaded socket or aperture 8 in the burnery head 2, the other end of the tube being arranged to receive a flexible hose or gathering tube 9 by means of which air or air mixed with the gases to be detected is supplied to the burner head.

The burner head or casing 2, in the specific structure illustrated by way of example, comprises a casting which is cored or drilled to provide a combined mixing and suction chamber I0 provided at one end with an outlet passage or borev I I and at the other end with an inlet bore or passage indicated generally by I2, and an inlet bore or passage indicated generally by I3. Outlet passage or bore II is provided with screw threads to receive a removable burner tip or nozzle I4. Inlet bore or passage indicated generally by I2 has a portion |20., connected to socket 8 and pipe 4, which is arranged centrally of and in longitudinalalignment with the outlet bore or passage II, portion I2a leading into and terminating in two divergent branch passages or bores |212! and I2c which open into the chamber I0 at the end thereof opposite outlet II.

I3d, the arrangement being such that the injec-v tor nozzle I3d is arranged centrally of the chamber I0 and in longitudinal alignment with the outlet passage or bore II. The portion |317` of the inlet indicated generally-by VI3 is provided with a conical valve seat I3e to receive a needle valve |3| threaded in an extension of the borer |31), the valve, provided with the handle |32, projecting laterally from the burner'head or casting. A gas-tight connection about the stem of the needle valve |3| is provided by means of suitable packing |33 and gland nut |34 which is threaded onto a lateral extension of the casing 2'.

It will be clear from the particular construction and arrangement just described that, when inlet passage I3, comprising the longitudinally extending portion I3a, the laterally extending 30, portion |311, the longitudinally extending portion I3c providedv with the longitudinally extending injector nozzle I3d, is supplied with acetylene or other suitable combustible gas under pressure by the pipe 5, this gas, passing through the injector .nozzle into the chamber I0 at high velocity, will induce or create a high or strong suction and draw air or air mixed with the gas to be detected into said chamber through the inlet passage I2 comprising the portion I 2a and the divergent branch passages I2b and I2C; consequently air or vair mixed with the gas to be detected will be drawn through pipe or tube 4 and the flexible hose 8 connected thereto. Not only Will the injector nozzle |30, create considerable suction in chamber I0, but because of the location and arrangement ofthe parts just described, a thorough mixing of the gases or gases and air will take place to form a perfectly combined combustible mixture and this mixture will be discharged through the outlet passage II and the nozzle or burner tip I4 connected thereto, to be burned. Because of the perfect combustion, a very hot substantially colorless ilame Will be produced. 'I'he fact that the inlet passage I2 extends longitudinally and centrally of the burner head, providing a smooth, substantially unobstructed passage for flow of air or air mixed with gas to be detected, which passage is in substantial alinement with the outlet, and the location of the injector nozzle I3d projecting toward and of considerable convenience in actual use. v

in longitudinal alinement with the outlet and besure through the comparatively small injector,v

nozzle, the expanding gas has a tendency to cool the combined suction and mixing chamber and thus prevent overheating of the burner head.

Mounted on the burner head 2, by means of screw threads or similar fastening means, is a tubular portion or shield I5 provided With air inlet openings I6 and an observation Window or opening I'I. Shield I5 which surrounds the heating or combustion zone of the burner 2 supports the reaction element or member I8 secured by means of a screw, rivet or similar fastening means I 9 to the shield I5. Reaction element I8 may consist of copper, nickel, or any other suitable material which reacts with the gas to be detected to form a substance which emits a characteristic light when heated, and may vary in shape, Within the broad scope of the invention.

Vannular frusto-conical body of copper which is supported so that it is heated by the substantially colorless flame provided by the ignited combustible mixture discharged from the burner tip I4 and is visible through the observation opening I1 in shield I5. This flame is ordinarily produced by a combustible mixture of acetylene or other combustible gas and air, but when even mere traces of the halide gas or gases to be detected are introduced through the burner tip or nozzle I4 into proximity to or contact with the heated copper reaction element I 8, the ame is immediately colored a brilliant green, and thus a very sensitive positive test for gases of the character indicated is provided.

The shield I5 constitutes an important feature of this invention because upon it depends to a considerable extent the accuracy, reliability and sensitivity of the test. In functioning as a shield, element I5 becomes very hot and therefore it is essential that it be made of a material which is free from any substance which would color the flame. In the present instance, therefore, shield I5 is made from a special grey cast iron which is free from nickel and other elements or compounds which might affect the color of the flame. Such material is not only desirable because it will not color the flame, but it produces a dark background or pocket which makes observation of the ame very easy.

The particular construction and arrangement of the reaction element or member I8, in cooperation With the shield I5, has been found in practice to provide a very sensitive, accurate and reliable test for gases of the character described. The slotted construction and the annular frustoconical shape of the member I8 makes it possible toV expose a maximum surface, which lls a large part of the cross-sectional area of the shield, and thus obtain maximum sensitivity without unduly obstructing the flame o1' flow of the products of combustion.

Another important feature of the invention resides in the means, indicated generally by I 9a, for collecting or gathering the gases to be detected, the arrangement being such that not only is a constant uninterrupted supply of air provided for the burner, but a sample or quantity of gas or gas mixed With air can be collected and temporarily held and not released or passed to the burner for a test until convenient to do so. As illustratedin Figs. l and 4, the collecting means I9 comprises a tubular member 20 having an end 2| adapted to receive the inlet end of the flexible tube or hose 9. For convenience, tube 20 is slightly bent intermediate its ends, the end 22 being provided with a removable fitting or nozzle 23 provided With a substantially conical or inclined passage 24 terminating in a. restricted opening 25. Fitting 23, with its inclined passage 24 and restricted opening 25, constitutes a restricted inlet opening to receive the gas to be detected, the particular construction and arrangement making it possible to locate with extreme accuracy the source of a leak. As it is usually desirable to provide the burner with more air than can be drawn through the tting 23, the tube 20 is provided with two longitudinally spaced holes 26 and21. These holes or air inlet openings are selectively controlled by a tubular valve member 28 rotatably mounted on the tube 20. Holes 26 and 21 in tube 20 are arranged at an angle of substantially to each other and sleeve 28 is also provided with holes 29 and 30 at an angle of substantially 90 to each other, the arrangement being such that in one position of the valve sleeve 28, holes 26 and 29 are in register and holes 21 and 30 are out of register, and in the other position of the sleeve, holes 26 and 29 are out of register and holes 21 and 30 are in register. In order to limit rotation of valve sleeve 28, it is provided adjacent one end with a substantially slot 3| which receives a pin or screw 32 carried by tube 20.

t will be obviousv from the foregoing that the air inlet openings 26 and 21, one of which is a1- ways open, provide a constant uninterrupted supply of air to the burner, but as previously noted, these holes also function in another and very important way. In using the device to detect a leak, the valve member 28 is arranged so that the holes 26 and 29 are in register and the end of the tube containing the tting 23 is then placed in close proximity to the suspected leak. Due to the suction of the burner, air is sucked or drawn in through the registering holes 26 and 29 and, if there is a leakage at the point suspected, gas to be detected, usually mixed with air, is drawn in through the opening 25 in fitting 23, the relative sizes ofthe openings being arranged so that there is always the desired amount of suction through each opening. The tube 20 is held at the point of the suspected leak until at least that portion vof the tube between air inlet opening 26 and the gas inlet opening 25 is filled with gas to be detected, usually mixed with air, after which the valve sleeve 28 is moved to close opening 26 and open air inlet opening 21. The air rushing in through this opening rapidly conveys a measured volume or slug of gas to be detected, consisting principally of the contents of the tube between openings 26 and 21, to the burner, with the result that a very positive and sensitive test is provided, the gas, when it reaches the flame or heated reaction element I8, causin a very noticeable flare-up of color.

Another important advantage of the construction just described resides in the fact that itis possible to collect a sample o-r quantity of gas to be tested and hold it for a short interval of time before passing it on to the burner for a test. This is a very desirable feature because it frequently happens that it is impossible or inconvenient for the operator to carry the burner with him or have it where he can readily see it. In such a case, the operator first collects a sample of gas to be detected in the tube 20, with inlets 25 and 26 open, and then moves or turns so that he can see the burner, the gas to be detected or tested being held or trapped in the tube between openings 25 and 26. Valve sleeve 26is then rotated to open air inlet 21 and close inlet 26 and a measured volume or "slug of gas is then rapidly passed to the burner for a test, as previously described.

Figs. 5 and 6 illustrate a modified form of the invention which is broadly similar to that illustrated in Figs. 1 to 4, but in this case the invention is embodied in a burner or blow torch adapted to use liquid fuel. Except for certain distinctions which will be pointed out, the description of Figs. 1 to 4 inclusive applies generally also to Figs. 5 and 6 and therefore the construction illustrated in these latter figures will merely be briefly described.

Referring to Figs. 5 and 6, 5| indicates generally a torch or burner, suitable for burning alcohol or any other liquid fuel capable of producing a substantially colorless flame. Burner or torch 5| comprises a burner head or body 52 provided with a threaded portion 52a by means of which it is secured to a tank 51 provided with a handle 53 and a pump 51a for providing pressure in the tank. Burner head 52 is provided with the usual cup 52h to receive liquid fuel which is burned to heat up the burner when irst starting. Burner head 52 is provided with tubes or pipes 54 and 55, the latter extending down into the liquid fuel to supply the same to the burner and tube 54 is arranged to receive a flexible hose or gathering tube 59 by means-of which air or air mixed with the gases to be detected is supplied to the burner head.

The burner head or casing 52 comprises, in the specific example illustrated, a casting which is cored or drilled to provide a combined mixing and suction chamber 5|0 provided at one end with an outlet passage or bore 5|| and at the other end with an inlet bore or passage indicated generally by 5| 2, and an inlet bore or passage indicated generally by 5|3. One end of inlet bore or passage 5|2 is connected to pipe 54, the other end leading into and terminating in two divergent branch passages or bores 5|2b and 5|2c, only one of Which is shown in Fig. 6, said branch passages opening into the chamber 5|0 at the end thereof opposite outlet 5| The other inlet passage or bore indicated generally by 5|3 comprises a portion 5|3c, which is connected at one end to the pipe 55, the other end having a reduced portion 5132; which terminates in a longitudinally extending portion or bore 5|3c fitted with a threaded removable injector nozzle 5|3d, the arrangement being such that the injector nozzle 5|3d is arranged centrally of the chamber 5|0 and in longitudinal alinement with the outlet passage or bore 5| and between divergent branch passages or bores 5|2b and 5|2c of the other inlet. The portion 5|3c of the inlet indicated generally by 5|3 is provided with a conical valve seat 5|3c to receive a needle valve |35 threaded in bore 5|3c and provided with a handle |36, projecting from the burner head or casing. A gas-tight connection about the stem of the needle valve |35 is provided by means of suitable packing |31 and gland unit |33 which is threaded onto a lateral extension |39 of the casing 52.

It will be clear from the foregoing description that, when inlet passage 5|3 of burner head or casing 52 is provided with liquid fuel under pressure through the pipe 55, the burner head first having been heated in the usual way, the liquid fuel will be vaporized or gasied as it passes through the portion 5|3a, the restricted portion 5|3b and the portion 5|3c and will be discharged under pressure through the injector nozzle 5|3d and will thus induce or create a high ory strong suction which will draw air or air mixed with the gas to be detected into chamber 5I() through the inlet passage 5I2 including the divergent branch passages 5I2b and 5I2c; consequently air or air mixed with the gas to be detected will be drawn through pipe or tube 54 and the exible hose 59 connected thereto. A thorough mixing, of the gasified fuel and air or air mixed with the gas to be detected will also take place, the combustible mixture being discharged through the outlet passage 5I I and burned within the tubular portion or shield 5I5 which is detachably connected to the burner head or' casing 52.

The reaction element or member 5i8 is similar to the reaction element described in connectionwith Figs. 1 to 4, but in this case, this 'element is mounted so that it maybe movedout of the heating zone or -ame of the burner. The means for movably supporting reaction element 5I8 may differ widely withinthe scope of the invention, but in the example illustrated this member is secured to a bell crank lever or member 5 I 9 pivotally connected at 520 to a ring 52| which is clamped by means of screw bolt 522 to the shield 5l5, the member 5I9 being provided'with a handle 523 by means of which the members 5I8 and 5I9 can be moved to shift the member 5I8 into and out of position in the'heating zone of the burner head.

This movable mounting of the Vreaction elementV 5I8 constitutes an important specific feature of the invention because it permits the reaction elementor member 5I8 to be moved to inoperative position when it is desired to test the burner to see Whether there is any substance or material causing coloration of the llame, other than the reaction element itself;

The shield 5I5 is preferably made of a special grey cast iron, free from any substance which v would color the ame, as in the case ofshield I5 described in connection withFigs. 1-4 and the means for collecting the gas or gases to be de-l tected, with or without air, is as explained in connection with said figures. Thev general operation and advantages of the modication illustrated in Figs. 5 and 6 are similar to those set-'out in connection with Figs 1-4.

It will be observed from the foregoing discussion of the invention that both forms provide a compact, simple, portable, inexpensive, troubleproof unit or combination which will provide a quick positive and accurate test for gases of the type indicated and which will clear up quickly after each test. As an indication of the sensitivity and of the superior suction created, tests show that apparatus embodying this invention is sensitive to and will indicate leaks of as low as 0.06 pound of gas per month and that a suction of better than 1/2 inch is attainable. v

Although the burners disclosed are designed for use in connection with the detection of gases, they are capable of general use as brazing torches, blowpipes, etc., merely by removing the reaction element or moving it out of the flame or heating zone and in some cases removing the shield. When used as a blow-torch, the rubber hose is preferably removed. Many different burner tips can be used and an additional valve controlled air inlet 4a is provided in the form illustrated in Figs. 1-4 for use when the device is used asa torch.

It is to be understood that the invention is not limited to the exact arrangements shown and described and that various changes may be made without departing from the spirit and scope of the broad invention as claims.

What is claimed is: 1. Apparatus for detecting gases, comprising a burner, including a tubular ame-shielding portionsurrounding they combustion Zone of said burner and formed from iron free from reactive flame-coloring material, a copper reaction element carried by said tubular portion and supported in the heating Zone of said burner, said element reacting with the gas to be detected to form ia substance which emits a characteristic light when heated, said element comprising a slotted annular frusto-conical body, and means for bringing the gas into contact with said member including a exible conduit, and a tubular member connected thereto and provided at one end with a restricted inlet opening for gas to be detected and provided with at least two relatively large longitudinally spaced air inlet openings and dened in the appended means for opening and closing said air inlet openings. v

`2.; Apparatus for detecting gases comprising, in

combination, a member which reacts with thel gasto be detected to form a substance which emits a characteristic light when heated, means for heating said member including means for creating suction, and means for conveying the gas tosaid-.memben said last-mentioned means including means providing an inlet opening for air mixed with the gas to be detected and a plurality of longitudinally-spaced openings for air between said rst inlet opening and said member and means for controlling said air inlet openings.

3. Apparatus for detecting gases comprising, in

combination, a member which reacts with the gas to be detected to form a substance which emits a characteristic light when heated, means for heating said member including means for creating suction, and means for conveying the gas to said member, said last-mentioned means including means providing a restricted opening for air mixed with the gas to be detected and at least two relatively large longitudinally spaced air inlet openings Y`between said iirst inlet opening and said member, and means operable to simultaneously open one air inlet and close the other and vice versafor controling said air inlet openings.

4. Apparatus for detecting gases comprising, in combination, a member which reacts with the gas to be detected to form a substance which emits alight when heated, means for heating said member including means for creating suctionfand means for conveying the gas to said member including a tube provided at one end with a restricted inlet opening for the gas to be detected, said tube being provided with at least two longitudinally-spaced air inlet openings,`and a rotatable sleeve mounted on said tube and operable to open one of said air inlet openings and close the other.

5. Apparatus for detecting gases, comprising a burner, including a tubular dame-shielding portion surrounding the combustion zone of said burner and formed from a material free from reactive :dame-coloring material, a reaction element carried by said tubular portion and supported in the heating zone of said burner, said element reacting with the gas to be detected to form a substance which emits a characteristic light when heated, and means for bringing the gasto be detected into contact with said member including a tubular member provided at one end with a restricted inlet opening for gas to be detected and provided with at least two relatively large longitudinally spaced air inlet openings and means for opening and closing said air inlet openings.

6. Apparatus for detecting gases, comprising a burner, including a tubular flame-shielding portion surrounding the combustion zone of said burner and formed from material free from reactive name-coloring material, a reaction element carried by said tubular portion and supported in the heating Zone of said burner, said element reacting with the gas to be detected to form a substance which emits a characteristic light when heated, said burner having a combined mixing and suction chamber, an outlet at one end of said chamber and a plurality of inlets at the other end of said chamber, one of said inlets being arranged to provide a passage terminating in diverging branch passages opening into said chamber and the other inlet being provided with an injector nozzle mounted adjacent the divergent branch passages of the rst inlet and arranged to deliver combustible gas under pressure to said chamber and draw air through said rst inlet into said chamber and deliver a combustible mixture through said outlet, and means to deliver air mixed with gas to be detected to said rst inlet, said means including a tubular member provided at one end with a restricted inlet opening for gas to be detected and provided with at least two relatively large longitudinally spaced air inlet openings and means for opening and closing said air inlet openings.

'7.y Apparatus for detecting gases comprising, in combination, a member which reacts with the gas to be detected to form a substance which emits a characteristic light when heated, a burner for heating said member, said burner having a combined mixing and suction chamber, an outlet at one end of said chamber and a plurality of inlets at the other end of said chamber, one of said inlets being arranged to provide a passage terminating in diverging branch passages opening into said chamber and the other inlet being provided with an injector nozzle mounted adjacent the divergent branch passages of the first inlet and arranged to deliver combustible gas under pressure to said chamber and draw air through said rst inlet into said chamber and deliver a combustible mixture through said outlet, and means to deliver air mixed with gas to be detected to said rst inlet, said last-mentioned means including means providing an inlet opening for air mixed with the gas to be detected and a plurality of longitudinally spaced openings for air between said rst inlet opening and said member and means for controlling said air inlet openings.

WILLIAM KEIFFER. HULL.

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