US2796296A - Nozzle exit valve - Google Patents

Description

3 Sheets-Sheet l Filed April 27, 1953 N9. @.N E @w mw mm t om,

INVENTOR. M//A/ 'f7 cAMPf/ L @Mg WM A 7701EA/ '575.

mm RN June 18, 1957 J. F. CAMPBELL 2,796,296

NozzLE EXIT VALVE Filed April 27, 1953 s sheets-sheet 2 Z s Z f //54 3l I1 l 3l 50 /4 30 :fig #(95 INVENTOR. 10H/v E CAMPBELL.

June 18, 1957 J. F. CAMPBELL NOZZLE EXIT VALVE Filed April 27, 1953 3 Sheets-Shea?l 3 JNVENToR.

/0/-N E CAMPBELL United `States Patent O NOZZLE EXIT VALVE `lohn F. Campbell, Euclid, Ohio Application April 27, 1953, Serial No. 351,287

6 Claims. (Cl. 299-107.6)

This invention relates as indicated to a nozzle exit valve, and more particularly to a particular ty-pe of nozzle valve especially adapted for use in spray nozzles of the type disclosed in my co-pending applications Serial No. 105,975, filed July 21, 1949, now Patent No. 2,656,- 218, and Serial No. 333,569, led January 27, 1953, now Patent 2,749,182, of which this application is a continuation-in-part.

Reference may be had to said co-pending applications for a more detailed explanation of certain of the problems involved in the design of spray nozzles for use in internal combustion engines and especially jet engines, and also for a more detailed explanation of the manner in which uid may be conducted to the exit orifice of the nozzle to obtain the desired effects. p

There are at present several different types of engines employing liquid fuels which require to be injected into the combustion chambers of the same, such engines including the well-known automotive internal combustion engine, diesels, the turbo-jet, prop-jet, and ram-jet engines and the like. While such latter types of engines are at present largely employed in aircraft, it is expected that they will shortly find application in railway locomotives and ships. In certain-of such engines it is necessary to provide for a wide range of fuel ow between selected minimum and maximum limits while at the same time maintaining a low over-al1 pressure drop through the nozzle between the fuel intake manifold and the combustion chamber.

Open orifice type nozzles have been employed in the past in such applications but without any great measure of success, principally because of their limited ow range of approximately l to 1. The ow range which must be obtainable for continuously efficient operation of certain of the more modern jet engines is in some cases as much as 125 to 1. The usual open orifice nozzles are not capable of any such range of performance since in such nozzles when the rate of flow is increased by a stated factor the corresponding line pressure will require to be increased approximately by such factor squared. To attempt to provide for any great range of flow with this latter type of nozzle is therefore wholly impracticable as leading to impossibly high line pressures in the upper range of flow.

With closed and/or variable orifice nozzles I have,

however, found it possible to obtain a wide range of flow without excessive intake pressures being required to achieve high ow rates. A serious diiculty with this latter type of nozzle, however, is encountered in attempting to meet the rigid specifications generally imposed as to maintenance of a designated angle of spray cone at all operating rates of flow. When the rate of flow drops v to conform to a designated predetermined pattern, and this has likewise been found very difficult to achieve.

As explained in my aforesaid co-pending applications, I have developed a novel form of nozzle which has proved to be highly efcient and to afford the desired characteristics over a wide range of ow. v

It is usually desirable to maintain the spray envelope produced by the nozzle at a substantially constant angle over such large ow range. Ifthe valve orifice and the exit valve member cooperating therewith are provided with opposed seat portions to afford a particular Vangle to the spray envelope, it is found that at high rates of flow the fuel envelope discharged from the orifice will assume a rounded or umbrella shape instead of holding to the desired conical form as obtained at low fuel flow. The general result of this effect is equivalent to reducing the angle of the conical fuel envelope, and such change of angle is not tolerated by present-day engine specifications.

It is accordingly a principal object of my invention to provide a novel form of nozzle exit valve and particularly of the exit valve member itself which will automatically produce the desired form of spray pattern or envelope at the various different rates of flow, with the exit valve member being adjusted accordingly axially of the exit orifice.

Other objects will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention `then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

Fig. l is a longitudinal sectional view of one embodiment of my new nozzle as shown and described in'my aforesaid application Serial No. 333,569 and showing the manner of mounting the exit valve member and its relationship to the swirl chamber immediately upstream of the exit orice;

Fig. 2 is an enlarged view in cross-section of the exit end of the nozzle illustrating one contour of my new exit valve member;

Fig. 3 is a View similar to Fig. 2 but showing the exit valve member shifted to a more open position and not sectioned;

Fig. 4 shows a modified form of exit valve member;

Fig. 5 shows such exit valve member shifted for further opening of the valve;

Fig. 6 shows another form of exit valve member;

Fig. 7 illustrates the manner in which an annular or circumferential vent may be provided in my new exit valve member for venting the interior of the nozzle into the spray envelope; and

Figs. 8 and 9 illustrate yet another form of my new exit valve member.

Referring now more particularly to Fig. 1 of the drawing, the embodiment of my invention there illustrated comprises an outer nozzle body 1 of general cylindrical form having an enlarged base portion 2 adapted to bel lar recess 8 opposed to a corresponding annular recess 9 formed in the outer body member 1 and the inner liner member 10 press tted therein. An annular filter 11 ywhichmay be of 'asbestosvfiben forexample held between layers'oftilter cloth 12 and 13 is'interposed between such annular recesses .8 and `9 and firmly clamped between kmembers 1 and 3 so that fuel or other liquid entering recess 8 through passage 7 can reach annular cavity 9 only through such filter.

The other end of the nozzle body is closed except for an axially disposed exit orifice 14. All parts of the vnozzle may desirably be of stainless steel, for example.

As above indicated, the inner liner member is press fitted within cylindrical nozzle body 1, such liner being 'provided with a plurality of longitudinally extending grooves in its outer surface adapted to form channels or 4passages in conjunction with the inner cylindrical wall 15 of nozzle body 1. Liner 10 is likewise of cylindrical shape, its inner periphery 16 defining the axial bore within which valve member 17 is adapted to slide. In the embodiment illustrated, ten equally spaced grooves 18 are provided in the outer periphery of member 10 opening to the end of such member toward exit orifice 14 but closed at their other ends. Five somewhat smaller' Agrooves (not shown) are similarly formed in the outer periphery of liner 10 intermediate every other pair of such grooves 18 but such additional grooves do not extend quite to either end of liner 10. Instead, generally radial passages lead therefrom directly to the inner bore 16 of the liner at a point to the left of the valve member 17 so that such latter passages are always in communication with intakepassage 6.

For convenient manufacture and assembly, a separate .annularfmember 22 is fitted over end liange 23 of liner 1l),

being interposed therebetween and the outer end 24 of the nozzle body. As shown, such member is thereby spaced from the inner cylindrical wall of nozzle body 1 and is formed with a plurality of tangential slots 2S opening into a swirl chamber 26 immediately upstream of nozzle Yexit orifice 14. Accordingly, fiuid admitted to channels 18 by reciprocation of valve member 17 is caused to enter chamber 26 through such diagonal slots .25 in communication therewith, imparting an accelerat- .channels (not shown) which communicate directly with bore 16 and inlet passage 6 to the left of valve member 17 lead to such annular chamber 28 so that even when valve member 17 has not been reciprocated to admit fluid from intake passage 6 to channels 18, iuid may flow through such other channels to annular channel 28 and small helical grooves 29 leading to swirl chamber 26.

vvValve member 17 comprises a cylindrical shell closed toward the fuel inlet end of the nozzle but open toward member 27. Such valve member fits closely within bore 16 of liner 10 for axial reciprocation therewithin.

Exit valve member 3f) extends through exit orifice 14 and is provided with a radially outwardly fiaring flange 31 adapted to engage and seat against the outer edge of such orice. An inner stem 32 fits closely for axial reciprocation within a central bore in member 27 Slide valve member 17 and poppet valve member 36 are interconnected for movement together by means of a rod 33 (a fine spring wire, which in one case had a diameter of .014 inch) which extends through tubular valve stem 32 and is secured as'by brazing at its Aouter end to aplug 34 in the outwardly protruding portion of exit valve member 30. Such tubular stem '32 is open Aatits 4 inner end to the interior of bore 16 of liner 10 and at its outer end communicates with a small chamber within valve member 30 having small exit orifices such as 35 leading to the exterior of the nozzle. The other end of rod 33 is secured to an adjusting screw 36 threaded within the end of valve member 17, the protruding end of screw 36 being engaged and enclosedby a lock nut 37. A cornpression spring 38 is seated at one end against a washer 39 bearing against the end of valve member 17 and at the other end bears against inner plug 27. It will thus be seen that by turning screw 36 valve member 17 may be drawn toward plug 27 with attendant further compression of spring 38 and more forceful seating of poppet valve member 30.

Steel rod 33, although slender, is straight and therefore capable of causing both valve members 17 and 30 to reciprocate in unison. Such rod is, however, flexible to permit a slight degree o'fmisalignment of such two valve members without tending to cause the latter to bind. It is important in nozzles of this type that they be quite sensitive and responsive to changes in fluid pressure. By securing the ends of rod 33 in adjusting screw 36 and the extreme outerendiof valve member 3f) respectively as by low temperature brazing, a relatively long rod may be employed facilitating such slight deflection as may be required of the same. It may be kept invmind that frequently nozzles of the type here under consideration are only an inch or so long, and the various moving parts are accordingly on a very small scale. As well shown in Fig. l, adequate lateral clearance is provided for rod 33 to permit such deflection of the same. Compression spring 38 may desirably be formed from a length of tubing slotted by two helical slots terminating at diametrically opposite points in the annular end portions thereof. A spring thus formed is adapted to transmit pressure directly axially without canting. Any tendency of valve member 17 to'bind on this account is accordingly avoided.

As also shown in Fig. l, lanother longitudinally extending -channel is provided `formed 'by grooves 40 and 41 in the outer periphery of liner 10, groove 40 communicating with annular passage 9 through'constricted relief 42 and communicating with groove 41 through a similar relief 43. Consequently, filtered fluid willbe conducted through. transverse passages 44, 45 and 46 to the sliding fits of valve member 17 and valve stern 32. Contaminated fluid which has not been filtered but enters the nozzle directly through inlet passage 6 is thereby prevented from entering into such 'sliding fits since the filtered fiuid will be at somewhat higher lpressure (there is, of course, a

.considerable pressure drop from passage 6 to annular `particles which may under some circumstances become interposed between the relatively sliding surfaces and which would tend to reduce the sensitivity of the device. Only filtered uid reaches the interior of valve member '17. It will be seen that the operation of this anti-clogging `means is wholly automatic and requires no maintenance other than very occasional cleaning or replacement of filter 11. Since the fluidtiow through such filter is very slow, a long period will elapse before the filter will become clogged. Moreover, thenozzle considered as a Vwhole is now enabled to accommodate itself to contaminated fuels Without any special treatment of the latter passing therethrough and without any consequent reduction in flow.

Further details and modifications of the above-described nozzle construction are set forth more fully in my copending application Serial N0. 333,569 referred to above.

As previously indicated, the `present invention is more particularly concerned with the construction and operation ofthe exit valve memberI30, several embodiments of'which are illustrated 'inFigs' 2-9 of the drawing. Re-

ferring initially to the Figs. 2 and 3 form, it will be Vseen that the shoulder or peripheral ange 31 has a bevelled inner surface 48 adapted to seat and close exit orifice 14 and also, when Valve stem 32 has been only slightly reciprocated to the right as viewed in Fig. 2 to open the poppet valve but slightly, to direct the spray cone S at a rather large' angle, whereas when such valve stem 32 is shifted further to open the valve as shown in Fig. 3 the angle of the spray cone S is now determined by the more acute angle of conical surface 49 which is separated from the more obtusely conical surface 48 by an intervening generally cylindrical land 50. Such land causes the uid to break away from the valve member at the point where such land interrupts the conical surface 49 and the latte'r accordingly controls the angle of the spray cone at higher rates of flow.

Valve stem 32 is necked down at 51 where it extends through swirl lchamber 26, and it has been found that the iluid swirling rapidly around such stem portion 51 tends to adhere thereto as it passes through the exit orifice 14. It is accordingly ordinarily important that a land such as land 50 or a similar interruption be provided to break the fluid away from the surface of the valve member to form the spray cone S. Different jet engine kspecifications call for different spray cone angles at various rates of flow, sometimes smaller at high rates of llow and sometimes vice versa. Control-of the form of spray envelope may be achieved in accordance with my invention by proper selection of the conical surfaces such as 48 and 49.

Figures 4 and 5 illustrate a modification of my invention similar to the Figs. 2 and 3 embodiment but with conical valve surfaces 52 and 53 selected to aiord a spray cone of relatively small angle when the valve is only slightly open as shown in Fig. 4 and a spray cone of considerably larger angle when the valve is relatively widely opened as shown in Fig. 5. In the former instance, the fluid escapes from the exit valve orifice where'the latter is opposed to conical surface 53 whereas in the latter instance it escapes where conical surface 52 is adjacent the valve orifice 14. The cylindrical flat 54 provides a break between such two conical surfaces whereby the swirling uid is caused to break away from the valve member into the spray cone S.

Now referring to Fig. 6 of the drawing, I show a valve member in which the conical surfaces 55 and 56 are of substantially equal angle although separated by the intervening cylindrical at 57. Such flat serves to provide a more constricted annular orifice for the escaping fluid when the valve is only slightly opened as shown in Fig. 6, and when the valve member has been reciprocated considerably further to the right, conical surfaces 55 will then control the angle of the spray cone. -It is thus possible to obtain a spray cone of substantially uniform angle throughout the opening and closing movement of the exit valve member at different rates of flow.

The Fig. 7 embodiment is somewhat similar to the Figs. 2 and 3 embodiment in that the spray cone' is at a somewhat wider angle when the valve is initially opened than later when such valve is widely opened. Instead of providing openings such as 35 (Fig. 1) for escape of vented fluid, however, an annular opening 58 is provided in the inner face of the conical valve surface initially determining the angle of the spray cone. The' vented lluid accordingly is discharged directly into such spray cone for incorporation therein without substantially modifying the characteristics of the same.

It will be seen therefore that the spray cone or sheaf is formed by the outer or primary cone for small amounts of valve opening and by the' inner or secondary cone for large amounts of valve opening. For intermediate degrees of opening, the spray cone angle is formed by fluid blending between the primary and secondary conical surfaces. Such blend point is selective' relative to the amount of valve opening by proper selection of the diameter and length of the intermediate cylindrical portion.

In Figs. 8 and 9' of the drawing it will be noted that the nozzle orifice 14 is provided with an outer beveled valve seat 59 adapted to seat the corresponding beveled surface 60 of exit valve 30. When such valve is only slightly opened as shown in Fig. 8, the swirling uid is discharged through the orifice at an angle determined by such parallel spaced seat portions 59 and 6i). By providing a more obtuse conical contour (i. e. of greater vertex angle) to the inner beveled surface 61, the angle of the spray envelope will be determined by whichever surface 60, 61 is more nearly juxtaposed to seat 59. Consequently, as indicated in Fig. 9, when the valve is relatively widely opened with a large fuel -llow passing through the nozzle orifice, the angle of the conical spray envelope is relatively wide near its apex, thereby counterbalancing the tendency to form a rounded shape and maintaining the desired angle within prescribed limits. A succession of more than two such conical surfaces of increasingvertex angles may be provided, or a continuous curved surface may be utilized to obtain somewhat the same effect. I generally prefer, however, to utilize an intervening cylindrical surface as shown in Figs. 247 inclusive between the two conical surfaces in order to ensure a definite transition from one spray cone angle to another when such is desired. Without such marked interruption in the poppet valve surface opposed to the exit orice 14, the swirling action of the fluid (e. g. jet engine fuel) tends to cause the same to cling to the valve member so that the outer conical surface maintains an undesired influence on the spray cone even when the valve is quite widely opened.

It will, of course, be noted that when the exit valve member is reciprocated from slightly open to fully open position -the two different conical surfaces thereon are sequentially opposed to the outer edge of the exit oriiice 14. Such orifice will ordinarily be of cylindrical conformation and of relatively short longitudinal extent compared to the sum of the two conical surfaces of the valve member and the usual intervening land. Itis the cooperative effect of such on'tlceand the adjacent portion of the valve member which determines the shape of the spray cone or sheaf at different rates of flow. As above indicated, the exit valve member automatically moves further outwardly as the rate of flow increases. The swirling movement of the uid about the constricted valve stem due to the helical inlet passages leading to the swirl chamber immediately upstream of the orifice causes such uid to follow the contour of the valve member as it passes through the annular opening and thereby to assume the desired conical form as well as assisting in the ultimate separation of the fluid into minute droplets.

The cylindrical lands intermediate and spacing the conical surface portions of the tappet exit valve member aiord the desired transition without such a break in the fluid ow as might cause uncontrolled turbulence. The fluid flow enters the swirl chamber 26 through a plurality of angularly arranged inlet passages (helical passages 29 n and tangential inlets 25) and is wrapped around valve stem 51. The portion of the valve member juxtaposed to the outer edge of exit orice 14 substantially determines the form of the spray cone delivered.

The. spray cone angle and desired changes therein at different rates of flow are specified for best results for use in different designs of jet engine burners, for example, and my exit valve construction makes possible the accurate control desired. When conical surfaces 55 and S6 (Fig. 6) are of the same vertex angle it will nevertheless be seen such surfaces are axially offset and the break formed by land 57 helps prevent the swirling liquid in circular swirl chamber 26 from continuing to cling to the surface beyond the end of portion 57 when the valve is widely opened. The Figs. 8 and 9 arrangement is relatively inexpensive and has been found satisfactory for large capacity nozzles. Ordinarily, however, the employment of a step, break, or land intermediate the conical surfaces is much preferred for the reasons indicated.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, Yprovided the features stated in any of the following claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a nozzle having an exit orifice and an axially reciprocable tappet valve member adapted to seat in such orifice, a primary conical portion on said member adapted to seat against the outer edge of such orifice when the valve is closed and to determine ythe initial angle of the spray cone delivered by such nozzle when such valve is opened, and a secondary conical portion on said member upstream of said primary conical portion and having a smaller vertex angle than said primary conical portion, said secondary conicalportion being adapted to be juxta posed to such outer edge of such orifice when the valve is more widely opened and then to determine such spray cone angle, the vertices of both such cones lying upstream of said primary conical portion, and said upstream secondary conical portion being axially spaced from said primary conical portion a sufficient distance to ensure that such spray cone determined thereby will clear said Aprimary conical portion despite the greater vertex angle of the latter.

2. In a nozzle having an exit orifice and an axially reciprocable tappet valve member adapted to seat in Vsuch orifice, a primary conical portion on said member adapted to seat against the outer edge defining such orifice when the valve is closed and to Idetermine the initial angle of the spray cone delivered by such nozzle when such valve is opened, a secondary conical portion on said member upstream or" said primary conical portion adapted Vto be juxtaposed to such outer `edge of such oriiice when the valve is more widely opened and `then to determine `such spray cone angle, the vertices of both such cones lying upstream of said primary conical portion and pointing in the same direction with the projected surface of said secondary conical portion completely clearing the surface of said primary conical portion, and a cylindrical land intermediate said conical portions directly joining the same, with the smaller end surface of said primary conical portion terminating at one margin of said land and the larger end surface of said secondary conical portion'terminating at the other margin of said land.

3. In a nozzle having an exit orifice and an axially reeiprocable tappet valve member adapted to seat in such orifice, a primary conical portion on said member adapted to seat against the outer edge defining Vsuch orifice when the valve is closed and to determine the initial angle of the spray cone :delivered by such nozzle'when such valve is opened, a secondary conical portion on said member upstream of said prima-ry conical portion adapted to be juxtaposed to such outer edge of such orice when the valve is more widely opened and then to determine such spray cone angle, the vertices of both such cones lying upstream of said primary conical portion and pointing in the same direction with the projectedsurface of said secondary conical portion completely clearing thc surface of said primary conical portion, and a land intermediate and spacing said conical portions directly joining the same, with the smaller end surface of said primary conical portion terminating at one'margin of said land and the larger end surface of said secondary conical portion terminating at the other margin of said land.

4. In a nozzle having an exit orifice and an axially reciprocable tappet valve member adapted to seat in such orifice, a primary conical portion on said member adapted to seat against the outer edge of such orifice when the valve is closed and to determine the initial angle of the spray cone delivered by such nozzle when such valve is opened, a secondary conical portion on said member upstream of said primary conical portion adapted to be juxtaposed to such outer edge of such orifice when the valve is more widely opened and then to determine such spray ,cone

angle, the vertices'of both such cones lying Vupstream of vsaid .primary :conical `portion and pointing in the same direction, .the projected surface of said seconda-ry conical vportion .completely clearing the surface of said primary conical portion, a land inteimediate and spacing said conical portions directly joiningthe same, with the smaller end surface of said primary conical portion term-inating at one margin .of saidland and the larger end surface .of said secondary conical portion terminating at the other margin of said land, a swirl chamber immediately upstream of such exit orifice through Which the stem of such tappet valve member passes, and a plurality of angularly disposed fluid inlet passages leading into said swirl chamber adapted to deliver a swirlingiluid llovv about such stem.

5. In a nozzle having a cylindrical exit orifice kand an axially reciprocable tappet valve member adapted to seat in such orifice, `a primary concalzpo-rtion on said member adapted to seat against the outer edge of such orifice when the valve lis closed and to 'determine the initial angle of the spray cone delivered `by such nozzle when such valve is opened, a secondary conical portion` on said member upstream of safd lprimary conical yportion adapted to ybe juxtaposed to such outer edge ,of such orifice when the vvalve is more Widely opened and then to determine such spray cone angle, the vertices `of both such cones lying upstreamof Vsaid primary conical portion and pointinng inthe same direction, the projected surface of said secondary conical portion completely clearing the surface ,of said primary conical portion, a cylindrical land'intermediate said conical portions 'directly joining the same, with the smaller end surface of said primary conical portion terminating 'at-one margin of said land and the larger end surface of said secondary conical portion terminating at -th'e other margin -of said land, a swirl chamber immediatelyfupstreamof lsuch exit orice through which the stem of such tappet valve member passes, and a plurality ofangularlydisposed:iluid inlet passages leading into said kswirlchamber adapted to deliver a Vswirling fluid flow about. such stem.

6, `In a nozzle having an exit oriice and an axially reciprocable tappet valve member adapted to seat in such orifice, twoaxially spaced conical portions on saidmember adapted selectively to ,determine the angle of the spray cone delivered by such nozzle from such orifice, said conical portions being directly connected by a cylindrical land, with the smaller end surface of said` primary conical portion terminating at one margin of said land and the larger end surface of said secondary conical portion terminating atthe other margin of said land, the vertices of .both such cones-pointing upstream witth the projected surface of said secondary conical portion completely clearing .the surface of said primary conical portion, a swirl cham- `ber upstream of :such exit orifice through which the stem of such tappet valve member passes, circumferential tangcntially disposed fluid inlets to said chamber, and separate angularly inclined fluid Ainlets tothe end of said .chamber kopposite Vthe ,end having such exit orifice, to deliver .a swirling fluid flow about such stem travelling out through such orifice.

References Cited in the le of this patent UNITED STATES PATENTS Germany Aug, 27, 19.30

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