US2248731A

US2248731A - Gas mixer

Info

Publication number: US2248731A
Application number: US157321A
Authority: US
Inventors: Lloyd W Young
Original assignee: Oxweld Acetylene Co
Current assignee: Oxweld Acetylene Co
Priority date: 1937-08-04
Filing date: 1937-08-04
Publication date: 1941-07-08
Anticipated expiration: 1958-07-08

Description

July 8, 1941. L w, YOUNG 2,248,731

GAS MIXER Filed Aug. 4, 1937 121111 Il Il A mllllllllllllllrafffv' IN VENT OR.

LLOYD W YOUNG BY ATTORNEY.

Patented July 8, 19,41

GAS MIXER Lloyd W. Young, Scotch i, N. J., assignor to Oxweld Acetylene Company, a corporation of West Virginia Application August d, 1937, Serial No. 157,321

16 Claims.

This invention relates to a gas mixer, and more particularly to a gas mixer includingan injector which may be used for mixing twoI gases by injecting one gas, under pressure, into the other. The invention is especially useful in its application to a gas-air torch, to which use, however, it is not limited.

In the art of applying heat by means of a heating instrumentality such as a blowpipe or a torch, a single blowpipe or torch is ordinarily used with a selected stem, tip, or the like, of a capacity appropriate to the work to be done. A mixing injector of metal is commonly employed to provide the gas mixture which is used by the blow= is applied:

Fig. 2 is a fragmental elevation ofthe torch illustrated in Fig. 1, partly in longitudinal midsection, shown on an enlarged scale;

Fig. 3 is a cross section of the torch taken on the line III---IJIl of Fig. 2;v

Fig. 4 is an enlarged longitudinal mid-section through the mixing injector inustrated in Figs. 1

pipe or torch. Upon undertaking a different kind' l5 of work with such apparatus, it is usually necessary to change the gas pressure, as by a needle valve, and to employ-a stern, tip, or the like, of different capacity, which generally requires, also, the use of a mixer ofl dierent capacity. Furthermore, the dimculty of drilling and centering the small orifices which are required in the smaller sizes of mixing injectors when made of metal, and the dimculty of the alternative process of swedging the injector over a Wire in order to produce the necessary small orifice, makes such metal injectors expensive. Still further, when the pressure of the gas passing through the mixing injector is reduced, the flame no longer remains neutral. Finally, because of the very small orifices which are employed in the smaller mixing injectors, it is necessary to screen the gas lcoming to thesevinjectorsto prevent stoppage of the orii'lces by impurities in the gas.

One object of the invention, therefore, is to provide a gas mixer whereby one gas may be aspirated by another to form a gas mixture of substantially constant proportions over a wide range of pressure of the aspirating gas. Another object is to provide a heating instrumentality including a gas mixer having a mixing injector which can be used with different gas pressures and with a plurality of tips of dierent capacities, to the end that each change of gas pressure-and of; tip will not also require a change of mixing injector. Another object is the provision of a mixing injector in inexpensive form. A further object is the provision of a mixing injector which will tend to produce a neutral flame regardless of the gas pressure. Still a further object is the provision of such an injector in a form which Awill not require screening of Agas coming to it in order to prevent stoppage of its orifice.

The above and other objects and novel features of the invention will be apparent from the followand 2;

Fig. 5 is asimilar enlarged mid-section through adiiferent form of mixing injector; and

Fig. 6 is a fragmental view, similar to Fig. 2, of a torch to which the mixing injector shown in Fig.v 5 is applied.

According to the present invention, an injector' formed of resilient material is employed to pro-v f ject a gas under pressure into another gas under a lesser pressure, or to project ai gas under pressure across atmospheric vents thereby aspirating air along with it, in order to mixthe two gases pressure of gas passing forwardly therethrough and will contract with lower pressure of such gas.

' The sameinjector may, therefore, lbe used with widely different gas pressure and with ldiii'erent Y stems, tips, or the like for doing different kinds of work. vif a xed diameter orifice were used, variation in acetylene pressure would cause variation'of the velocity, but insuiilcient variation in the quantity of acetylene flowing. through'the orifice to give a substantially constant mixture lwith the variable quantity of air aspirated by the different acetylene velocity, and hence the flame characteristics would change with chang ing acetylene pressures. It has been found that the u'se of a substantially soft rubber injector,A preferably of substantially conical form having.

an axial oriilce pierced through its apex, will be y self-acting .and will automatically control the ilow of acetylene in accordance with its pressure. Il'he self-acting resilient orifice of the injectorl of this invention will set up a condition within the gas mixer such that the velocity of the acetylene passing through the injector tends to remain substantially constant irrespective of variations of acetylene pressure. Actually, this acetylene velocity varies in accordance with its pressure,

and by virtue of the expansible and contr'actlble the hand-gripping element.

oriilce, the volume of acetylene owing through the orifice varies. However, the variation in velocity is only suilicient to aspirate the correct amount of air to combine with the variable quantity of acetylene iiowing through the orifice to produce a mixture capable of maintaining the flame characteristics substantially constant, even until the ilame is extinguished. As a result o! such constant llame characteristics. there is but tends forwardly to an inwardly projecting an nular shoulder 2l at the rear end of a chamber 2l formed in the body coaxiaily with the cavity -forward end of passage 26 between the mixer a slight problem of backilres such as occur in M and the main passage of stem T. An axial the ordinary gas-air torch having an orifice of fixed size designed for use over a certain limited range of pressures. In the ordinary torch, `when an attempt is made `to use at a low pressure an injector which is designed for a relatively high pressure. the acetylene enriched mixture produced at the low pressure is very susceptible to the propagation of backres. In the device of the present invention, however, the ratio of gas to air in the combustible mixture is substantially the same at any pressure of the gas because of the variation in the injector orifice size in accordance with the pressure, and the danger of backres is therefore negligible. Finally, should a backfire occur it will -close the oriiice in the injector momentarily, thereby acting to prevent passage of a burning or combustible mixture back of the injector. The injector may be` constructed in different forms, two being illustrated in the drawing by way of example.

-gether in series.

'I'he handle H comprises a hand-gripping element I0, which may be formed of wood, having an axial passage II extending therethrough. terminating in an enlarged cavity I2 at the forward end of the hand-grippingelement. A gas conduit I3 having its rear end formed as a hoseengaging nipple I4 extends through the axial passage II in the hand-gripplng element H, and is connected at its forward end, as by silver soldering, to a socket member I5 which fits snugly into the cavity I2 at the forward end of A locking nut Ii is threaded on the gas conduit I3 and bears against the rear end of the hand-gripping element Il to' hold the gas conduit I3 and the socket member I5 in place. The socket member I5 is formed with an annular ange II on its forward end which contacts the forward end of the handgripping element I0 when the socket member is in place. The socket member has an axial passage I8 therein which extends forwardly from its connection with the gas conduit I3k to an internally threaded socket I9 coaxial with lthe passage I8. Thus, the handle H has an axial gas passage therettuough comprising the passage through the gas conduit I3, the passage Il through the socket member I5, and the internally threaded socket IS `at the forward end of the socket member I5.

The mixing assembly M comprises a body 2l, having its rear end externally threaded, as at 2|, for connection with the internal threads in the socket I9. The forward end of the body l is internally threaded, as at 22, for engagement with the stem or tip T. Part of the periphery o! the body 20 isiormed as a hexagonal nut in order that a wrench may grip the body in making these connections.

An internally .threaded axial cavity 23 is passage of varying diameter .thus extends completely through the body 20 from the handle to the stem or tip.

The body 2l of the mixing assembly M is slightly reduced insection immediately ahead of the. external thread thereon and behind the hexagonal nut section, so that, when the mixing assembly is'scre'wed into the socket member Il, an annular space 2l is provided between the body 2l andthe socket member I5 ahead of the v connecting threads. Furthermore, the body and the socket member are so shaped that this space is open to atmosphere. Radial air holes 2B are formed in the reduced section of the body 20 and extend from the atmosphere into the chamber 2l. It is here noted that the outer ends of these radial air passages lie in the annularF space 21 and are thereby protected `from stoppage.

An injector or injector nozzzle 28 is disposed in the chamber 2l .in a position to project gas coming to the mixing assembly from the handle across the chamber and into the axial passage 26. The injector 28 will thus produce a subatmospheric pressure in the chamber 25, and will aspirato air from the chamber 25 into the passage 20. There the gas which is discharged by the injector will mix with the air, in a'wellknown manner.

The injector 28 is made of elastic resilient material, as soft rubber, and in the embodiment which is illustrated in Figs. 1, 2, and 4, the injector is of hollow conical shape and has an outwardly projecting ilange 30 at its rear end. The injector is inserted into the mixing body 20 through the cavity 23 and is held in place by means of a screw plug 3l, the forward end oi which bears upon the rear end ofthe injector 29 and compresses its annular flange 30 between the forward end of the screw plug and the annular shoulder 24 at the forward end of the cavity 23. The screw plug 3| has an axial passage, as a metering orifice 22, extending therethrough, and also has a kerf in its: rear end by means of which a screw driver or like instrument may be employed to screw theA plugint; the cavity 2l at the rear of the mixing body Since the injector 28 is made of resilient material, as soft rubber, it is inexpensive to manufacture. The oriiice therein may be pierced by a needle after the injector nozzle blank is in piace in :the mixing assembly. The metering oriilce in the screw plug Il serves conveniently as a guide for the piercing needle. After piercing, the resiliency of the material of which the injector is formed closesy the orlilce therein. Gas under pressure coming to the injector, however, expands the latter and opens the orifice -at a predetermined pressure (see dotted lines.

Fig. 4). Accordingly, the greater the pressure of `the gas coming to the injector the vla'rgerwill be the cross-sectional area of the orifice. 'Conversely. the lower the pressure of the gas coming to the injector the smaller will be the cross-secformed in the rear end of :the body 20, and extional area of the orifice. Thus, the volume of accessi Obviously. the sizes of the openings of the radial passages 2! into the chamber 25 are substantial- Y ly independent of the deformation of the aspirator injector nozzle 29 so that an adequate supply oi gas through the passages 28 may be maintained at all 'ressures of the gas discharge from the nozzle 2 It will also be apparent that if impurities clog the orifice, the pressure behind the impurities will build up, and the orice will expand until the impurities pass therethrough.

The stem or tip T which is illustrated in Fig. 1 is a gooseneck stem and tip combined, being externally threaded at its rear end for attachment to the threads 22 at the forward end of the mixing assembly M. Obviously, other types of stems or tips might be substituted for the one which is illustrated.

In the embodiment which is illustrated in Figs. 5 and 6, the injector 20 employed is not conical but is a. disc of deformable resilient material which is' supported adjacent to its edges, the major portion of the front face of the injector being otherwise free of support. Otherwise, the construction is precisely the same as that which has already been described. Clearly, an oric'e may be pierced in the disc injector 28 exactly vas in the conical injector 2l. Furthermore, theresiliency of the material will tend to close the orifice in the disc injector exactly as is the case with the conical injector; and pressure behind the disc will tendvto bow it forwardly and to open the orifice. 'Ihe dotted line in Fig. 5 illustrates the action of pressure upon the disc form of injector.

From the foregoing, it will'be apparent that the passage therethrough and a second passage there in joining the first passage, and an injector formed cf gas-pressure responsive resilient ma terial fixed in the mst-mentioned passage and provided with a self-closing orifice disposed in e. position to discharge across the junction of the mst-mentioned passage with the second.

3. In a gas mixer including a chammr, a first lgas passage, and a second gas passage opening into said chamber: an injector nozzle of elastic material, said nozzle having a self-closing orifice communicating with said Afirst passage and ar ranged to 'discharge gas into said chamber, said nozzle being deformable in response to pressure exerted thereon to open said orifice in response to a predetermined pressure and thereafter to render :the crosssect`ional area of said orice substantially directly proportional to the operat- .ing pressure.

4. In agas mixer including a chamber.- a first gas passage, and a second gas passage opening into said chamber: an injector communicating with said first gas passage and arranged to discharge gas into said chamben said injector comprising a nozzle of soft rubber deformable in response to pressure exerted thereon, said nozzle being provided with an orifice adapted to open'in accordance with increaseof the pressure on said nozzle.

5. In a gas mixer including a chamber, a first gas passage, and a second gas passage opening into said chamber: an injector nozzle communicating with said first passage and-arranged to discharge gas into said chamber, said nozzleA having a normally-closed orifice and being formed of a material resiliently deformable in response to gas pressure exerted thereon to open said orilice an amount inaccordance with thev pressure.

present invention provides a mixing injector which can be used with diiierent gas pressures and with tips of different capacities. Furthermore, the materlalrof which the injectors 'are made is inexpensive and the method of forming vthe orifices in them is easy and cheap. In addition. expansion and contraction of the orifice tends to produce a neutral flame regardless of the gas pressure, and also makes unnecessary screening of the gas, since impurities are easily forced through the expansible orifice.

The embodiments of the invention herein described and shown in the accompanying drawing are presented merely as examples of how the invention may be applied. Other forms. differing in detail but not in principle from those here disclosed, will, of course, suggest themselves to those skilled in the art.

I claimt 1. In a gas mixer including a chamber, a ilrs't gas passage, and a second gas passage opening into said chamber: an injector communicating with said first gas passage and arranged to discharge gas into said chamber, said injector com'- prising a nozzle having an orifice and being formed of an elastic material deformable in response to pressure exerted thereon to vary the cross-'sectional area of said orifice directly in accordance with the pressure.

J'2. A gas mixer comprising a body having a 6. In a gas mixer including a chamber, a'iirst gas passage, and a second gas passage opening into said chamber: an injector communicating with said first passage and arranged to discharge gas into said chamber, said injector comprising a rubber member having a normally-closed orifice, said member being deformable in response to pressure exerted thereon to open and close said orifice in accordance with the pressure of the gas passing therethrough.

7. In a gas mixer including a chamber, a rst,

gas passage, and a second gas passage opening into said chamber: a hollow conical aspirator in jector nozzle communicating with said first passage and arranged to discharge gas into said chamber, said nozzle being perforated at its apex to provide an orifice, said nozzle being formed of resilient material deformable in response to pressure exerted thereon to render the crosssec tional area of said orifice substantially proportional to the pressure, said orifice being normally closed by the natural resiliency of said material.

8. In a gas mixer including a chamber,-a first gas passage, and a. second gaslpassage opening into said chamber:y a substantially disc-shaped' injector communicating with said rst passage and arranged to discharge gas into said chamber, said injector being vformed of resilient deformable material and having an orifice therein, said injector being deformable in response to gas pressure exerted thereon to open. said orifice an amount directly in accordance with the pressure.

9. In a gas mixer `including a chamber, a rst gas passage, and a second gas passage opening' into saidchamber: a substantially disc-shaped injector communicating with said first '-.-.=-.s.. and having an orifice arranged to discharge gas into said chamber, said injector being supported adjacent to its edges, the major portion of the front face of said injector being free of support, and said injector being formed of resilient deformable material whereby pressureapplied behind said injector will bow said injector forwardly, thereby opening said orifice an amount directly in accordance with the pressure.

10. In a heating instrumentality, a gas mixer comprising a body having a first passage therethrough including a chamber, and a second passage opening into the chamber and adapted to communicate with a supply of gas to be aspirated; and an injector nozzle secured in said first passage, said nozzle having an orifice for discharging aspirating gas into said chamber, said nozzle being formed of a material resiliently deformable in response to pressure changes to vary the crosssectional areaof said orifice directly in accorci-I ance with such pressure changes.

11. In a heating instrumentality, a gas mixer comprising a body having a first passage therethrough including a chamber, and a second passage opening into the chamber and adapted to communicate with a supply of gas to be aspirated; and an injector nozzle secured in said first passage, said nozzle having an orifice for discharging aspirating gas into said chamber, said.

nozzle being formed ofa material resiliently deformable in response to pressure changes to vary the cross-sectional area of said orifice directly in accordance with such pressure changes; the size of the opening of said second passage into said chamber being substantially independent of the deformation of said nozzle.

12. In a heating instrumentality, a gas mixer comprising a body having therein chamber, a first gas supply passage and a second gas supply passage terminating in the chamber, and a gas discharge passage leading from the chamber; and an injector nozzle secured in said first passage for discharge into the chamber toward the disinto said chamber, said nozzle being formed of a resiiiently deformable material and having an orifice normally closed by the natural resiliency of said material, said nozzle being deformable to open said orifice in response to a predetermined gas pressure exerted therein and to vary the cross-sectional area of said orice in accordance with variations of the pressure exerted therein; the size of the opening of said second passage into said chamber being substantially independent of the deformation of said nozzle.

14. In a gas-air torch, a mixer body having a longitudinal passage therethrough and substantially radial air ports communicating with thev longitudinal passage, and an injector formed of resilient material having a self-acting gas-pressure responsive orifice fixed in the longitudinal passage through s'aid mixer body in a position to discharge across the openings of the airports, said injector being deformable in response to pressure variations in said orifice to vary the cross-sectional area thereof in accordance with the pressure to maintain a substantially constant velocity of gas discharge therefrom.

15. In a gas-air torch, a mixer body having an internally threaded longitudinal cavity formed in its rear end extending forwardly to an inwardly projecting shoulder at the rear end of a chamber formed in the mixer body coaxially with the cavity, an injector formed of resilient material having a gas discharge orifice the effective open 16. In a gas-air torch, a mixer body having an internally threaded axial cavity formed in its charge passage, said nozzle having an orifice for discharging aspirating gas into said chamber, and said nozzle being formed of a material resiliently deformable in response to pressure changes tovary the cross-sectional area of said orifice directly in accordance with such pressure changes; the size of the opening ci' said second passage into saidI chamber being substantially independent of the deformation of said nozzle.

13. In a heating instrumentality.v a gas mixer .comprising a body having a first passage therethrough including a chamber, and a second passage therein joining the first. passage in the chamber and adapted to communicate with a supply of gas to be aspirated; and an injector nozzle secured in said first passage for discharge sage extending forwardly from the chamber o therein coaxially with the axial passage through said screw plug and a plurality of radial passages extending therethrough from atmosphere to the chamber.

. LLOYD W. YOUNG.