US2197979A - Blowpipe - Google Patents

Description

April 23, 1940. H. w. JONES ET Al.

BLOWPIPE Filed Aug. so, 1958 2 Sheets-Sheet 1 .dmLl

sm www OOO C mJ. .m WWW, -..m N T Imm A M OB HR m April 23, 1940. H. w. JONES ET AL BLOWPIPE Filed Aug. 50,1958 2 sheets-sheer 2 INVENTRS H HOMR WJONES ATTORNEY ERBERT W. COWIN BY Patented Apr. 23; 1940 PATENT. N OFFICE -l BLOWPIPE Homer W. Jones and Herbert W. Cowin, West- Afield, N. J., assig'nors to Oxweld Acetylene Company, a. corporation of West Virginia applicati@ august so, 193s, serial No. 227.412 19 claims. (ci. 15s-21.4)

This invention relates to blowpipes and more particularly to a self-igniting blowpipe adapted to operate with W pressure fuel gas and provided with-means for insuring the maintenance of a I small pilot flame after the main iiame has been extinguished.

With the various types of self-igniting blowpipes heretofore used with low pressure fuel gas, diiiiculty has been experienced in maintaining a l l0 pilot flame at the blowpipe nozzle whenthe main supply of combustible gas mixture has been interrupted. In blowpipes of this type, the relatively high pressure oxygen passes through a mixer and, by an injector action, aspirates the relatively low pressure combustible gas (e. g., acetylene) into the mixer. `The acetylene for Vsupporting the pilot flame is usually by-passed around the main acetylene control valve. If the oxygen valve is closed suddenly,the injector action is abruptly interrupted and not only is the pilot flame extinguishedbut there is also danger of a flashback or burning within the blowpipe itself. This is particularly true of the type of blowpipe in'which a pair of adjustable valves are used to control the proportions of the combustible mixture of acetylene and oxygen, and a second vpair of quick shut-off valves are used for turning on and off the supply of acetylene and oxygen to the blowpipe tips.

80 'Ifo overcome these diiculties, a blowpipe arrangement has been devised in which means are provided for delaying the closing action of the above-mentioned quick shut-olf valves and for insuring that the closing movement of the valve controlling the supply of oxygen fs not completed until after the closing movement of the valve controlling the main supply of acetylene-has been completed. while at the same time a small pilot ame is maintained on the blowpipe tip. The

same time differential means insures that a reduced flow of oxygen to the blowpipe nozzle is initiated before the acetylene is turned on. thus preventing undesirable formation of soot due to too muchfree burning combustible gas.

It is therefore among the objects of this invention to provide a blowpipe for operation with low pressure fuel gas and including means to maintain a small pilot flame 'when the main flame is extinguished; to provide a blowpipe in- '50 cluding means for securing a time differential in the operation of the shut-oil' valves controlling the supplies of combustion supporting gas and' combustible gas, respectively; to provide a blowpipe including means for delaying the closing action of these shut-off valves; and to provide a blowpipe havinggood flashback resistance, and

which is economical to manufacture, simple in construction, and emcientin operation. These and other objects of the invention will in part be obvious and in part become apparent from aconsideration of the following description and the accompanying drawings, in which:

Fig. 1 is a side elevational .view of one form of blowpipe embodying the invention, with parts broken away and other parts in sectionA to il- 10 lustrate certain novel features of the invention:

Fig. 2 is a longitudinal sectional view through the blowpipe illustrated in Fig. 1;

Fig. 3 is a transverse section view on the line 3--3 o f Fig. 2; y 15 Fig. 4 is a transverse sectional view on the line 4-4 of Fig. 2;

Fig. 5 is a view similar to Fig. 1 of another form of blowpipe embodying the principles of the invention; 20

Fig. 6 is a view taken o`n the line 6-6 of Fig. 5 looking in the direction of the arrows;

Fig. 7 is a transverse sectional view on the line 1-1ofFig.5; Fig. 8 is a transverse sectional view on a some- 25 what larger scale taken on 'the line 8--8 of Fig. 5: and

Fig. 9 is a. somewhat enlarged view of a modification of the blowpipe shown in Fig. 5.

For convenience, in the following description, 30 the term acetylene will be used to denote any suitable combustible gas and the term oxygen will be used to denote any suitable combustion supporting gas. y In blowpipes designed for operation with low 35 pressure acetylene (less than about 1 lb. per sq. in.) and highpressure oxygen .(about 30-35 lbs. per sq.. in.) the combustible mixture is obtained by passing the oxygen through the injector of a.

suitable mixer, whereby the resultant vacuum o thus created causes the acetylene to be drawn into the mixer and thoroughly intermixed with the oxygen. Some blowpipes Vare equipped with pilot light arrangements in which a portion of the acetylene is by-passed around the acetylene shut- 4,5 ofi' valve so that a small flame may be maintained at the blowpipe nozzle when the main supply of combustible mixture is interrupted.

In this type of blowpipe. it is necessary to maintain at. least a reduced iiow of oxygen after the main iiow of acetylene has been interrupted in order to clear out any combustible mixture present between the mixer and the blowpipe tip.

It is desirable to prevent the supply of combustible mixture from beingabruptly interrupted .1

and to cause such supply to be reduced gradually to prevent a snapping back of the iiame and to l prevent blowing out of the pilot light by the high pressure oxygen present between the shut-oil! valve and theblowpipe tip or nozzle. It is desirable also to initiate the oxygen supply iirst, in lighting the blowpipe, to prevent the deposition of soot in the mixer, the stem and the tip due to a large volume of free burning acetylene.

For the above reasons, the present invention is directed to th'"provision, in a blowpipe equipped with pilot light means, of separate shut-ofi valves for the oxygen and acetylene, which valves are located between the usual adjustable throttle valves and the blowpipe tip, and to the provision of means for insuring a sequential opening and closing of these shut-oil' valves and for insuring a gradual reduction in the iiow of the combustible mixture when the shut-ofi.' valves are being closed.

Referring particularly to the embodiment of the invention illustrated in Figs. l to 4, inclusive, there is shown a blowpipe comprising a valve body or block V, a tubular handle H, a front body F, a mixer assembly M, a stem assembly S, and a tip or nozzle N secured to the stem assembly by the usual clamping nut C. Oxygen enters the valve block V through a suitable nipple D, passes through the usual adjustable throttle valve A, and thence through a quick acting, lever operated, shut-off valve B into the oxygen tube T, from which it enters the mixer assembly M. Similarly, acetylene passes through inlet nipple D', valves A' and B' and acetylene tube T' to the mixer assembly M where it is mixed with the oxygen. Means are provided to deliver the combustible mixture from mixer assembly M through stem assembly S to the outlet of nozzle N. Other delivery means are provided to by-pass a portion of the acetylene through adjustable throttle or pilot valve P'around shut-oil' valve B' and into tube T' to provide a pilot flame at the blowpipe nozzle.

The quick acting lever operated shut-oil' valves B and B' are provided with controlling mechanism including sequential valve actuating means E and automatically operable retarding means R, to delay the closing movements oi' the valves, which means and mechanism, in combination with the other elements of the blowpipe, vform the novel subject matter of this invention.

Referring now in more detail to'Figs. 1 to 4, inclusive, oxygen under pressure from the pipple D enters through a passage I in valve body V to a valve chamber II in the throttle valve A. A throttle valve I2, actuated by threaded stem I3 having an external knurled head I4 thereon, seats upon the end of chamber II and admits, restricts or shuts oil! the supply of oxygen to a second valve chamber I 5; A duct I8 in` the body V connects chamber I5 to a central oxygen passage I I forming part of the shut-off valve B.

'I'he valve B comprises a exible diaphragm I8, held in sealing engagement with a shoulder I 9 in a bore in the body V by an inverted, cup shape clamping nut 2 I. The diaphragmI8 seats on the end of passage II to control communication between this passage and an annular passage 22. A stem 23 is secured to diaphragm I8 and extends outwardly through nut 2I, where it is formed for engagement with the novel shut-off valve operating mechanism comprising the invention and which will be described more fully later herein. Spring 24, surrounding stem 23 between the inner end surface of nut 2I and a shoulder 25 on the stem normally urges the diaphragm I3 to `a valve closing position.

A duct 25 extends through body V from passage 22 and terminates in a counterbored portion in which is sealed one end of oxygen tube T. The other end of tube T is sealed in a counterbore in the front body F, and a duct 21 extends from tube Tito a chamber 28 in the body F. From the.chamber 28, the oxygen enters the central passage 29 oi' an injector 80 in the mixer assembly M and passes through the passage 29 to the stem assembly S.

Acetylene enters from the nipple D' through a passage 3| to a valve chamber 32 in the valve A' (which is identical to the valve A). A duct 34 in body V connects a second valve chamber 33, to the central passage 35 of the valve B', which is identical to valve B except that the inlet acetylene passage is larger in cross-sectional area than the inlet oxygen passage I1 in valve B. From the annular passage 36 of valve B', the acetylene may pass through a duct 31, acetylene tube T and duct 33 in front body F to a chamber 39 in body F. The rear end of the injector 30 is tightly engaged and countersunk in chamber 28 to form a seal between chambers 28 and 39. Oxygen leaving the forward end oi injector 39, aspiratesacetylene from chamber 39 through annular ducts-40 in the injector and through annular passages 4I between the forward end of the injector and the mixer casing 42 into the stem assembly S. A combustible mixture is thereby delivered through the outlet ofthe nozzle or tip N.

Acetylene for the pilot ilame passes from valve chamber 32 through a duct 43 to inlt chamber 44 in pilot valve P. An oriflced diaphragm member 45, seated against the end of chamber 44, separatesthis chamber from an outlet chamber 46. Communication betweenl the inlet and outlet chambers of valve P is controlled by a slidable stem 41, associated with the orifice in member 45 and secured to a flexible diaphragm 4l which, in turn, is held against a shoulder 49 by a hollow nut 50. A threaded adjusting s'crew 5I, on which is secured a friction plug 52, engages the outer end of stem 41 and is formed with a ker! 53 for engagement by a screw driver, or other suitable means, for adjusting the opening of the pilot valve. Spring 54, seated on member 45 and engaging a shoulder on stem 41 acts to retract the stem from the orifice when screw 5I is loosened. From the outlet chamber 46, a duct leads to the annular outlet passage 38 of acetylene shutoff valve B', thus permitting acetylene to by-pass this valve and supply a small quantity oi' acetylene to the tube T' at all times when the acetylene adjustable throttle valve A' is operi.

`As explained at the beginning of this description, an important feature of the present invention is the novel mechanism for opening and clos ing the shut-off valves B and B in a preselected sequence and for delaying the closing movement of both valves to prevent the deposition of soot du'e to free burning acetylene in the various blowpipe passages and the mixer M and tip or nozzle N, and to prevent extinguishing the pilot flame at the outlet of the nozzle N, One embodiment of such mechanism will now be described.

As best shown in Fig. 1, a bracket 56 is secured to the handle H adjacent a slot 51' in the latter.

Mounted on a pivot 58 on the bracket 55 is an operating member such as a lever 59 comprising an operating arm 60 extending rearwardly from thepivot 5l along the exterior of the handle H and a bell crank arm 6| disposed within the handle. The inner end 62 of the bell ,crank arm 6| is forked and pivotally connected to the piston 63 of adashpot mechanism 64, the' cylinder 65 of which is pivotally connected to a rib 66 on the rear end of the front body F.

. The base of the cylinder is bored radially to form a valve chamber 61, communicating with the atmosphere through a small port 68 and with the interior of the cylinder through a small port 69. An adjustable means such as a metering plug 10, threaded in chamber 61, controls the rate at which fluid escapes from the dashpot, and a filter 1|, of felt or other suitable material, is engaged by the plug adjacent the port 68.

The piston 63 is formed with a recess 12 in which is seated a spring 13. At its forward end,

spring 13 engages a spring guidev 14, comprising a` recessed base 15 apertured as at 16 and engaging the end wall of the cylinder 65, and'a rearwardly extending stem 11. The forward end of piston 63 is reduced to receive suitable packing 18 engaging the internal surface o'f cylinder 65 and held in placeby a packing nut 19.

As best shown in Figs. 4 and 1 the stem 23 of each quick shut-off valve B, B' is formed with a reduced threaded sectionon which is secured an adjustable bearing cap such as a flanged nut 8|. Two similar levers 82 are pivotally mounted at 83 on the forward portion of the valve body V. Each lever has a rearwardly extending angular arm 84 slotted to engage one of the stems 23 beneath the nut 8|. The forward arm 85 of each lever is curved to form a cam surface engaging a roller 86 rotatably mounted at the elbow of the bell crank arm 6| of the lever 59. The cam surface 81 of the oxygen lever is formed with a sharper degree of curvature than the cam surface 88 of the acetylene lever, whereby the roller 86 will rock the oxygen lever before it rocks the acetylene lever, when the operating lever 59 is depressed to open the valves B, B'.

In operation, lever 59 is depressed to open valves B, B', compressing spring 13 of dashpot 64. Valves A, A' are then manipulated to obtain the desired flame adjustment and pilot valve P is adjusted to provide a sufllcient ow of acetylene to maintain a pilot ame at the nozzle N. When lever 59 is depressed, the opening movement of the oxygen valve B is initiated before that of the acetylene valve B', due to the dierence in the cam surfaces 81 and 88, thus initiatingthe flow o f oxygen before the ow of acetylene and preventing the deposition of soot in the blowpipe, as previously explained.

When lever 59 is released, dashpot 64 delays the return movement of the lever to itsv normaly or initial position. In turn, roller 86 on lever 59 delays the release of levers 82. Thus, oxygen continues to enter mixer M to aspirate acetylene and the size of the main flame gradually diminishes, permitting any gas mixture in the blowpipe to pass through nozzle N and be consumed. When the valves B, B' are finally fully closed, a small quantity of acetylene continues to ow through pilot valve P so that a small flame is maintained at the end of nozzle N. It will be noted that the controlling mechanism initiates the interruption in the flow of one gas before initiating the interruption in the flow of the other gas.

By the delaying action of the dashpot, and thev differential closing action of the cam surfaces 81, 68, flashback in the blowpipe is prevented and the flow of oxygen is reduced gradually so that a. the pilot flame will not be blown out. It should be noted thatthe function of preventing the blowing out of the pilot flame is performed bythe retarding mechanism R. Therefore, the sequence of operation. of valves B, B' -may bealtered, or the valves may be designed to operate simultaneously, without affecting the action of mechanism R in maintaining the pilot ame.

Except for changes in the disposition of valves A, A' and B, B', and in the construction of valves B, B', the modified arrangement shown in Figs. 5 to 9, inclusive, is similar to that heretofore described, 'and like reference characters are used to denote like, or corresponding. parts.

In the modified construction, the main throttle valves A and A' although identical in internal construction and operation with those heretofore described are separate from the body V, and are secured in counterbores 89, 90 in the rear of body V. The valves B, B' are mounted in the forward portion of body V (see particularly Figs. 6' and 8). The central inlet passages |1, 35 and the annular outlet passages 22, 36 are drilled in the body V. Each valve member comprises a sleeve diaphragm 9|, moulded around the inner end of the stem 23, and clamped between a sleeve 92, sealed to a shoulder 93 in the annular outlet passage 22 or 36 by suitable means such as solder 94, and a hollow clamping nut 95 threaded on the outer end of the sleeve. A spring 24, surrounding each stem 23 and engaging a suitable shoulder 96 on the stem at one end and an inner sleeve 91 surrounding the stem and engaging thelnut 95 at the other end, normally urges each valve to a closed position.

In this construction, oxygen enters through the valve A,. and passes through duct I6, inlet passage l1, outlet passage 22, and oxygen tube T (which communicates with the 'outlet passage) to the mixer assembly M. Similarly, acetylene passes through valve A', duct 34, passages 35 and 36, and acetylene tube T to the mixer assembly. The gas for the pilot flame enters pilot valve P from duct 34 through duct 43 and passes therefrom through another duct (not shown) to the outlet chamber 36.

A bracket 98, formed on the inner end of valve body V, pivotally supports the operating levers 99 fon the valves B. B'. The forward ends |00 of the levers have identical cam surfaces engaging the roller 86 on lever 59. The rear end |0|, |02, of each lever extends inwardly and is suitably slotted to engage the rounded under surface of the head |03 of an adjusting bolt |04 threaded in a recess in the outer end of each stem 23. The rear end |0| of the oxygen lever makes a smaller angle with the forward end than does the-rear end |02 of the acetylene lever (see Figs. 5 and 6). Accordingly, when lever 59 is depressed, the oxygen valve B will be opened before 'the acetylene valve B', and, when lever 59 is released. oxygen valve B will close last.

In this modification. as in the form of blowpipe shown in Figs. l to 4, the dashpot mechanism delays the closing action of the vshut-off valves and thereby prevents blowing out of the pilot flame. Similarly, the time differential in the operation of the valves B, B' may be varied or reversed without affecting the operation of the retarding mechanism R. This permits wide latitude in the adjustment of the blowpipe for various special conditions without disturbance of the mechanism for maintaining a pilot flame on nozzle or tip N.

Fig. 9 illustrates another manner in which the time differential operation of the valves B, B' may be attained, and which permits ready adiustment of the sequence of operation. As shown in this |00, and adjustment for the sequential opening of the valves is attained through relative adjustment of the bolts |04 in the stems 23.

- As the modifications shown in Figs, 5 vto 9, inclusive, operate in the same manner as that shown in Figs. 1 to 4, inclusive, further description of such operations seems unnecessary.

It should be noted that the rate of oper ation of the dashpot 6l, as controlled through adjustment of metering plug 'l0 with respect to post 68, is critical, as the time delay in the closing of valves B, B must be accurately adjustable to insure maintenance of .the proper size pilot flame without anyundue waste of gas.

While the valves B, B' have been shown as associated'with the valve body V in both-instances, it will be obvious that these valves could be associated equally well .with the front body F.

From the foregoing description, it will be apparent that. the blowpipe of' this invention includes a:novel combination of elementsenhancing the flashback resistance of theblowpipe and insuring the' maintenance of a pilot flame on the blowpipe tip or nozzle. This combination includes the quick shut oi valves B, B', the sequential operating means E and the retarding'mechanism R; By varying the relativecurvature of the forward ends of the levers 82) in the modification shown in Figs. 1 to 4, or of the rear ends of the 1evers'99 in that shown in Figs'. 5 to 8; or by fadjustment of the bolts |04 in the form shown in Fig. 9, either the flow of oxygen or the '-ow of acetylene may be initiated first and terminated last, or both may be turned on and off simultaneously. In any instance, both shut off valves are. controlled by the single operating lever 59 and the retardingmechanism will .functionequally well to insure maintenance of the pilot ame on the tip or nozzle N.

While certain embodiments of the invention .have been illustrated and described in detail, it will be obvious that the invention may be otherwise embodied and the dimensions and interrelation of parts changed so long as the 1objects of the invention are attained.

I0= We claim:

2. A blowpipe as claimed in claim 1, in Awhich said mechanism includesadjustable means controlling the rate of operation of said retarding means.

3. A blowpipe comprising, in combination, a

nozzle; a tubular handle carrying said nozzle;

means for delivering a combustible mixture of fuel gas and combustion-supporting gas through the outlet Aof said nozzle to produce a ame; and mechanism for controlling the ilow of both the fuel gas and the combustion-supporting gas which form saidv mixture, such mechanism comprising means operable to shut off such mixture-forming gases, and means within said handle and operable automatically to retard the action of such shutting-off means.

4. A blowpipe comprising, in combination, a nozzle; means for delivering a combustible mixture of fuel gas and combustion-supporting gas through the outlet ofsaid nozzle to produces. main flame and for delivering fuel gas thro'ugh said. outlet to` provide a pilot flame while the deliveryof such combustible mixture is interrupted, said pilot flame being adapted to reignite such mixture when the delivery of the latter is re-established; and mechanism for controlling the flow of both the combustion-supporting gas and the fuel gas which form said mixture, such mechanism comprising means operable to shut off such mixture-forming gases, and means operable automatically to delay the action of such shutting-oil means, to avoid extinguishing said pilot ame.

5. A blowpipe as claimed in claim 4, inA which such shutting-off means is constructed and arranged to initiate the interruption of the flow of one of such mixture-forming gases before initiating the interruption of the flow of the other mixture-forming gas.

6. A blowpipe as claimed in claim 4, in which said mechanism includes adjustable means for controlling the rate of operation of said delaying means.

7. A blowpipe comprising, in combination, a valve block; a tubular handle; a nozzle having an outlet; means for delivering a combustiblemixture of fuel gas and combustion-supporting gas through said outlet to produce a flame; and mechanism for controlling the delivery of both th'e fuel -gas and the'combustion-supporting gas which form such mixture, such mechanism comprising throttle valves, a shut-off valve interposed between each of said throttle valves and said nozzle, means for actuating said shut-off valves. and means operable automatically to retard the closing of said ,shut-off valves after the latter have been operatedvby said actuating means.

8. In the blowpipe claimed in claim 7, means for maintaining a pilot flame adjacent the nozzle outlet when vsaid shut-oiyalves are closed.

9. The blowpipe claimed in claim 7 in which all of. said valves are mounted on said valve block.

10. The blowpipe claimed in claim 7 in which said shut-oil? valves are mounted on said'valve block and 'within said tubular handle.

11.l Intheblowpipe claimed in claim 7, means, including an adjustable throttle valve mounted on said valve block and interposed between the throttle valve and the shut-off valve controlling the fuel gas, for maintaining a pilot name adjacent the nozzle outlet when the shut-olf valve controlling the fuel gas is closed.

12. In a blowpipe, in combination, a valve block having oxygen and fuel gas passages therein; a nozzle; oxygen and fuel gas tubes communicating with said nozzle; throttle valves controlling the admission of oxygen and fuel gas to said passages; shut-off valves interposed between said tubes and said passages; mechanism for operating said shut-oi valves automatically in a preselected sequence; and means for delaying the closing of said shut-oil valves.

13| A blowpipe as claimed in claim l2, in which said valve block is formed with a duct intersecting said fuel gas passage between the throttle valve and the shut-ol! valve and communicating with the fuel gas tube between the shut-oil valve and the nozzle to maintain a pilot flame adjacent said nozzle when the fuel gas shut-off valve is closed.

14. In a blowpipe, in combination, a valve block having oxygen and fuel gas passages therein; a

pair of throttle valves respectively controlling the admission of oxygen and fuel gas to said oxygen l and said fuel gas passages, respectively; a front body; a tubular handle connecting said front body to said valve block; a nozzle secured to said front body; tubes in said handle for respectively conducting oxygen and acetylene from said passages to said front body; oxygen and acetylene shut-off valves adapted respectively to permit or prevent the flow of oxygen and acetylene from said passage.; to said tubes; a pair of levers pivotally connected to said valve block and each operatively associated with one of said valves, said levers each being formed with a cam surface; an operating member pivotally connected to said handle; and means on said operating member engaging said cam surfaces to initiate the operation of said rst-named levers and said shut-oil valves in a preselected sequence.

15. In the blowpipe claimed in clai'm 14, means for maintaining a pilot 4ame adjacent said nozzle when said shut-off valves are closed; and a dashpot mechanism operatively connected to said front body and said operating member for delaying the operation of said shut-off valves.

16. In the blowpipe claimed in claim 14, means for maintaining a pilot flame adjacent said nozzle when said shut-off valves are closed; a dashpot mechanism operatively connected to said front body and said operating member for delaying the operation of said shut-off valves; and a metering plug operatively associated with said dashpot mechanism.

17. The blowpipe claimed in claim 14, in which said shut-oil valves are each provided with an adjustable bearing cap engaging one of said levers.

18. The blowpipe claimed in claim 14, in which said cam surfaces are identical and said levers are each provided with an end portion bent at different angles to the main body of the lever

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