US3587970A

US3587970A - Fluid injectors

Info

Publication number: US3587970A
Application number: US811916A
Authority: US
Inventors: David Tindall; Arthur Michael Needham
Original assignee: J AND T ENGINEERS ASCOT Ltd
Current assignee: Spectus Energy Ltd; J AND T ENGINEERS ASCOT Ltd
Priority date: 1968-04-02
Filing date: 1969-04-01
Publication date: 1971-06-28
Anticipated expiration: 1988-06-28
Also published as: DE1915569C3; GB1231631A; DE1915569B2; FR2010457A1; DE1915569A1

Abstract

THE INVENTION COMPRISES A FLUID INJECTOR INCLUDING A CHANGEOVER VALVE SELECTIVELY MOVABLE INTO ONE POSITION IN WHICH TO CONDITION THE INJECTOR FOR FLUID DISCHARGE AND INTO ANOTHER POSITION IN WHICH THE INJECTOR IS CONNECTED FOR NONDISCHARGE BUT CONDITIONED TO ACCEPT A CONTINUOUS CIRCULATION OF FLUID THROUGH ITSELF WHEN IN SAID NONDISCHARGE CONDITION.

Description

United States Patent David Tindall Southampton;

Arthur Michael Needham, Backwell, Bristol, England Apr. 1, 1969 June 28, 1971 J & T Engineers (Ascot) Limited Apr. 2, 1968 Great Britain Inventors Appl. No. Filed Patented Assignee Priority FLUID INJECTORS 27 Claims, 6 Drawing Figs.

US. Cl 239/126,

239/125, 239/464 Int. Cl 1105b 9/00 Field of Search 239/124,

[56] References Cited UNITED STATES PATENTS 2,549,092 4/1951 Huber 239/125 2,579,004 12/1951 239/125 2,609,237 9/1952 239/125 2,613,997 10/1952 239/125 2,697,636 12/1954 239/125 2,743,137 4/1956 239/125 2,991,941 7/1961 239/125(X) 3,395,863 8/1968 Johnson 239/125 Primary ExaminerM. Henson Wood, Jr. Assistant Examiner-John J. Love Att0rney Lawrence E. Laubscher ABSTRACT: The invention comprises a fluid injector including a changeover valve selectively movable into one position in which to condition the injector for fluid discharge and into another position in which the injector is conditioned for nondischarge but conditioned to accept a continuous circulation of fluid through itself when in said nondischarge condition.

PATEN'T'EU JUN28 r911 SHEET 2 [IF 3 & vat a nut m5 Q 7 A Q A v a f /X mm m z. A M Q R mm N F Q M in H m R R Q m 0 MM. Wm YW 1 Q r 8 E: .5 Iv wv Reva my Q w DAVID T'INDQLL,

AQTHUL M. NQ'DIM INVENTORS ATTORNEY FLUID rmacrons This invention concerns improvements in or relating to fluid injectors.

According to one aspect of the invention there is provided a fluid injector including a changeover valve selectively movable into one position in which to condition the injector for fluid discharge and into another position in which the injector is conditioned for nondischarge but conditioned to accept a continuous circulation of fluid through itself when in said nondischarge condition.

In order that the invention will be well understood there will now be described one embodiment thereof, given by way of example only, reference being had to the accompanying drawings, in which:

FIG. I is a schematic sectional side elevation ofa fluid injector when shut off;

FIG. 2 is a similar view of the same injector when shut off, which shows the introduction of additional fluid circulating within the injector;

FIG. 3 is a similar view of the same injector when operative to discharge fluid;

FIG. 4 is a similar scrap view showing the injector in the discharge condition, but with the changeover valve thereof in a different position, so as to regulate the quantity of discharged fluid; I

FIG. 5 is a scrap section to a larger scale showing the forward end of the injector ofthe preceding FIGS.; and

FIG. 6 is a scrap section to a larger scale showing in constructional fonn the rear end of the same injector coupled to a means for adjusting the position of the changeover valve.

The fluid injector is primarily intended for incorporation in an oil fuel burner suitable for use in an oil fired boiler. Such burners are arranged in the furnace walls of the boiler for firing the boilers fuel. Oil fuel is used as the prime fuel for firing burners, or as a secondary fuel for igniting coal when that is the primary fuel. The boiler would generate steam, and have land, marine or other industrial applications.

The fluid injector includes a multipart barrel 1 supporting at its forward end an atomizer assembly 2. The barrel would be suitably mounted in the wall of the boiler with its forward end inset from the boiler interior. The atomizer assembly 2 com prises an orifice plate 3, a swirl plate 4 and a distributor plate 5.

The distributor plate abuts a cylindrical body 6 which is secured at its rear end to a multipart central tube 7. A tip sealing valve 8 is slidably mounted within the body 6, and is biased forwardly by a spring 9. When there is no fluid supply to the injector, the bias of the spring 9 is sufficient to urge the valve tip 10 into a discharge orifice 11 in the orifice plate 3 and so close that orifice. Normally, fluid is continuously supplied to the injector, and the position of the tip sealing valve 8 is controlled by the differential as between the supply and return pressure ofthat fluid, as will appear.

The barrel 1 includes fixed oil fuel inlet and return pipes 12 and 13 respectively. Those pipes would be coupled into a suitable oil fuel delivery and return circuit, the details of which may be conventional and form no part of the present invention. A changeover valve 14 is axially slidable within the central tube 7, and a control sleeve 36, and is movable between positions in which to effect oil flows within the injector as indicated by the arrows in the various FIGS.

In the position of the valve 14 shown in FIG. 1, the oil is supplied through the central tube 7, and passes via the atomizer assembly 2 to return through an annular duct 15 defined between the barrel 1 and the cylindrical body 6 and central tube 7. Such oil flow effects a differential pressure operating to close the valve tip 10 against the discharge orifice 11. Thus, no oil will be discharged from the injector. Even so, during that time there is a continuous circulation of oil within the injector. The quantity of fluid which circulates within the injector can be regulated, as will be later described.

In the position of the valve 14 shown in FIG. 3, the reverse oil flow occurs through the injector. In this case, the differential pressure acting on the valve 8 retracts the tip 10 thereof, against the bias of the spring 9, to open the discharge orifice. Oil will, accordingly, be discharged through that orifice. A proportion of the oil supplied to the injector will not be discharged but will return through the central tube 7. That proportion, and hence the quantity of oil which is discharged, can be regulated, as will be later described.

Describing now the forward end of the injector (which is best seen in FIG. 5) in more detaiLports 16 in the wall of the cylindrical body 6 provide communication as between the duct 15 and a chamber 17 located forwardly ofa shoulder 18 on the tip sealing valve 8. Distributor apertures 19 are provided in the distributor plate 5, and swirl passages 20 in the swirl plate. A swirl chamber 21 is located radially inwardly of that plate and between it and the discharge orifice ll. A central passage 22 lies behind the swirl chamber, and passages 23 are provided through another shoulder 24 on the valve 8;,.that shoulder lying rearwardly of the valve tip 10.

Thus, when the fluid flow is as shown in FIG. 1, owing to velocity head losses there will be a pressure drop across the passages 23 and across the distributor apertures 19 and swirl passages 20. The incoming fluid operative on the tip sealing valve 8 is, as a consequence, at a higher pressure than the outgoing fluid flowing through the duct 15 and thus operative on the valve 8 within the chamber 17. That fluid pressure differential, in conjunction with the relative areas of the valve 8 exposed to the fluid, is effective, as stated, to firmly close the valve with its tip 10 seating in the orifice 11 to prevent discharge therethrough. More particularly, the effective area of the valve 8 exposed to the greater supply pressure is that of diameter D including shoulder 25 thereof, whilst the effective areas exposed to the lower return pressures in the chambers 21 and 17 are those defined by the diameters d and (Dd) respectively.

When the fluid flow within the injector is reversed, then there will be a pressure drop across the atomizer assembly 2 and passages 23 as before but in the opposite direction, so that the fluid pressure in the chambers 17 and 21 are sufficiently greater than the pressure in the center tube 7 acting on the area of the valve defined by diameter D including shoulder 25 thereof, to urge the valve 8 away from the orifice plate 3, and so open the orifice therein to permit discharge therethrough.

As mentioned, the reversal of fluid flow within theinjector is controlled by the changeover valve 14.

The position of that valve 14 in relation to

ports

27, 28, also controls the relative proportions of fluid discharge through the discharge orifice 11, and fluid spill return flow through the central tube 7 when the tip valve 8 is open, and of fluid continuously circulated within the injector when the tip valve 8 is closed.

The valve 14 comprises a spool having a land 29 in sliding engagement with the central tube 7, and

lands

30, 31 in sliding engagement with the control sleeve 36. The

lands

29, 30, 31, define

therebetween chambers

32, 33. The chamber 32 is maintained in communication with the duct 15 by an aperture 35 provided between the control sleeve 36 and the central tube 7. Another chamber 34 is defined between the land 31 and a closure member 37 serving to close the rear end of the injector and make a liquid seal with a plunger 38 of the valve 14. That plunger would be operative manually or be connected to any suitable power means such as an electrical solenoid or air cylinder so as to be reciprocally movable under selective control. The

ports

27, 28 are provided in the wall of the control sleeve 36, and ports 26 are provided in the wall of the central tube 7.

When the changeover valve 14 is in the position shown in FIG. 1, the land 29 is positioned behind the ports 26 having direct communication with the fluid supply pipe 12 so that fluid will flow from that pipe via the ports 26 and into the central tube 7 to pass therealong towards the atomizer assembly 2. A return path from the duct 15 to the return pipe 13 is provided by way ofthe aperture 35 and the ports 27, such that the fluid will return from the duct 15 via the aperture 35 into the chamber 32 and pass therefrom via the ports 27 into the return pipe 13.

With the injector maintained in the shutoff condition as shown in FIG. 2, additional circulating flow may be introduced by connecting a central bypass passage 39 in the valve 14 via the chamber 33 to the ports 28 so that the fluid will pass therefrom into the return pipe 13. Care must be taken to ensure that the fluid flow returning from the duct into the return pipe 13 is not reduced, when the valve 14 is moved inwardly to introduce additional circulation within the injector.

To effect a discharge condition, the changeover valve 14 is moved inwardly to the position shown in FIG. 3 in which the land 29 lies forwardly of the supply pipe 12 and the ports 26 to interrupt communication between those ports 26 and the forward region of the central tube 7. Instead, the ports 26 com municate with the chamber 32 with the result that flow will occur into that chamber 32 and exit therefrom via the aper ture 35 into the duct 15. Return from the atomizer assembly 2 takes place via the central tube 7 to the land 29, and then through the central passage 39 in the valve 14 and ports 40 therefrom into the chamber 33, to exit via the ports 27 into the directly registering return pipe 13.

With the injector in the discharge condition the fluid spill return flow into the return pipe 13 can be regulated to obtain a corresponding variation in the discharge flow. A lesser fluid spill return flow and hence a greater discharge flow is obtained by moving the changeover valve 14 inwardly, so that the land 31 is caused to interfere with the fluid spill return flow from the chamber 33 via the port 27 into the return pipe 13. This fluid spill return flow can be shut off entirely by continuing to move the changeover valve 14 inwardly until it is in the position shown in FIG. 4. At this position the discharge flow will be a maximum for a particular size of discharge orifice 11, and a particular supply pressure.

Care must be taken to ensure that the tip sealing valve 8 can move to the discharge position shown in FIG. 3, before the fluid spill return flow is shut off entirely. Otherwise a hydraulic lock will be caused in the central tube 7, which will render the tip sealing valve inoperative.

The distribution of fluid flow as between discharge and return for a particular size of atomizer is also determined by the diameter a of the central passage 22 and the size and number of passages 23 in the tip sealing valve 8.

There is an annular gap 41 between the rear end of the control sleeve and the associated end 42 of the barrel. In the absence of that gap, there would tend to be a hydraulic lock when the changeover valve is retracted caused by fluid being trapped in the chamber 34. With the annular gap, such fluid will be displaced from the chamber and into the return pipe 13.

An external adjustment mechanism permits independent regulation of both the quantities of discharged fluid when the tip sealing valve is open, and fluid continuously circulated within the injector when the tip sealing valve is closed. The mechanism is so arranged that either adjustment can be made without interfering with the other setting.

From FIG. 6 it can be seen that an adjustment spindle 43 is in rigid connection with the plunger 38 of the changeover valve 14 at a power operative drive sleeve 44-. The spindle 43 slides in an adjustment sleeve 45 which is part of the power operator support frame 46. The spindle 43 is enclosed by a barrel 47 which is screwed in engagement with the sleeve 45. The barrel 47 abuts adjustment nuts 48 which are also in screwed engagement with the sleeve 45. Adjustment nuts 49 are in screwed engagement with the spindle 43 and form a land 50 which abuts a land 51 formed on the end of the sleeve 45. A land 52 is formed on the end of the spindle 43, and a land 53 is formed inside the barrel 47.

To adjust the circulating fluid within the fluid injector, as in FIG. 2, the nuts 48 are screwed inwardly so that the barrel 47 which abuts them can be moved in. Thus, the travel of the spindle 43 is restricted because the land 52 abuts the land 53, causing the valve 14 to move inwardly.

The fluid spill return flow is regulated, as shown in FIGS. 3 and 4, by the nuts 49 which abut the land 51, and they can be unscrewed allowing the spindle 43 a controlled inward movement.

An oil burner incorporating the fluid injector as described would also have an air register to provide the combustion air, a flame stabilizer to maintain the flame at the point where the fuel isinjected, valves to regulate and shutoff the air and fuel supplies, and an ignitor to initiate combustion.

The described fluid injector is advantageous in that during shutoff, fluid is continuously circulated through it to cool the injector and obviate the need for the injector to be retracted away from the interior of the boiler. Again, because of that continuous circulation, fuel cracking and blockage in the injector are obviated and there is no necessity for cleaning between discharge operations. The tip sealing and changeover valves are self-contained units, which permits their easy removal for service or replacing; the ingress of dust into the valve system is prevented because the changeover valve is enclosed in the center tube as an integral part of the injector. The fuel flow for a particular pressure can be maintained at constant volume when the injector is operated by presetting the circulating flow when the injector is in the shutoff condition; this feature is of importance in automatic boiler control since it permits taking-off and putting-on burners without disturbing the total fuel flow. By providing for a regulated degree of fluid spill return flow during discharge, a wider range of operation is obtained without reducing the quality of fuel atomization. The construction of the injector also allows the use of second fluids to further increase the range of opera tion, for a single atomizer. The components of the injector are so sized that the injector may be housed in standard carrier tubes.

We claim: 1. Fluid injector means, comprising: an injector body (1) containing a chamber (15) and including means defining inlet (26) and outlet (27) ports for connecting said chamber with fluid supply (12) and return (13) conduits, respectively;

fluid atomizer means (2) connected with an opening contained in said body, said atomizer means defining a discharge passage (11) communicating at one end with said chamber;

tip sealing valve means (8) for controlling the discharge of fluid through said discharge passage; and

changeover valve means (14) connected between said inlet and outlet ports for establishing first and second flow paths for operating said tip sealing valve means between closed and open positions, respectively, relative to said discharge passage;

said changeover valve means being further-operable, when said tip sealing valve means is in the open position, between a range of fluid discharge positions to vary the flow of fluid between said inlet and outlet ports and thereby produce a variable discharge flow through said discharge passage for a given fluid supply pressure applied to said fluid atomizer means.

2. Apparatus as defined in claim 1, wherein each of said first and second flow paths include at least portions of said chamber, and further wherein the direction of fluid flow through said chamber in said injector body is reversed when said changeover valve means is displaced between the positions effecting shutoff and opening, respectively, of said tip valve sealing means.

3. A fluid injector according to claim 1, wherein said changeover valve means is selectively movable into a fluid discharge position in which it shuts off said outlet port and hence provides for a maximum discharge flow through said discharge passage for a particular fluid supply pressure applied to said fluid atomizer means.

4. Fluid injector means, comprising:

an injector body containing a chamber and including means defining inlet and outlet ports for connecting said chamber with fluid supply and return conduits, respectively;

fluid atomizer means connected with an opening contained in said body, said atomizer means defining a discharge passage that communicates at one end with said chamber;

tip sealing valve means for controlling the discharge of fluid through said discharge passage;

changeover valve means connected between said inlet and outlet ports for operating said tip sealing valve means between closed and open positions, respectively, relative to said discharge passage, said changeover valve means being further operable, when said tip sealing valve means is in the open position, between a range of fluid discharge positions to vary the flow of fluid between said inlet and outlet ports and thereby produce a variable discharge flow through said discharge passage for a given fluid supply pressure applied to said fluid atomizer means; and bypass means operable when said changeover valve means is in a position effecting closure of said tip sealing valve means to define a bypass passage affording limited flow of fluid directly from said inlet port to said outlet port, whereby a portion of the fluid bypasses said body chamber to provide continuous circulation of fluid through the injector means when in the nondischarge condition.

5. Fluid injector apparatus, comprising:

injector body means containing a chamber and defining at one end a discharge passage (11);

tip sealing valve means (8) controlling the discharge of fluid through said passage;

means for applying first and second pressure differentials upon said tip sealing valve means to position said valve means in closed and open positions relative to said discharge passage, respectively, said pressure differential means including a first fluid flow path to one side of said tip sealing means, a second fluid flow path to the other side of said tip sealing valve means, and first passage means (23) extending through said tip sealing valve means to afford communication between said two flow paths, said tip sealing valve means being responsive to a fluid differential between said two flow paths to close said discharge passage when fluid flow occurs through said first (7) to said second fluid flow path, and to permit fluid discharge through said discharge passage when fluid flow occurs through said second to said first fluid flow path, said first passage means being dimensioned to effect a pressure drop in fluid flowing therethrough from one fluid flow path to the other, said second fluid flow path containing second passage means (19) so dimensioned as to effect a pressure drop thereacross in the fluid flowing through said second path; said injector body means con taining in concentrically spaced relation therein a tubular internal body portion (6, 7) having a forward end adjacent said discharge passage and a rearward end remote therefrom, said tip sealing valve means being slidably mounted entirely within said forward end of said internal body portion, said first fluid flow path extending from said valve means rearwardly within said internal body portion, said second fluid flow path extending from said valve means, in succession, forwardly and externally of said internal body portion, rearwardly through said second passage means, and rearwardly of and concentri cally about the outer surface of said internal body portion, said injector body means further containing inlet (12) and outlet (13) port means; and

changeover valve means (14) slidably mounted for linear movement within the rearward end of said internal body portion for movement between a first position in which said inlet and outlet ports are connected with said :first and second fluid flow paths, respectively, and a second position in which said inlet and outlet port means are connected with said second and first fluid flow paths, respec' tively.

6. A fluid injector according to claim 5, including orifice,

swirl and distributor plates arranged adjacent each other, said discharge passage being contained in said orifice plate, said further passage means comprising swirl passages contained in said swirl plate and distributor apertures contained in said distributor plate.

7. A fluid injector according to claim 5, wherein said tip sealing valve means has a large diameter section D and a smaller diameter section d interconnected by a shoulder, a chamber being defined to one side of said shoulder, said chamber being interconnected with said second flow path defined externally of said body to expose said shoulder to the pressure of fluid in said second flow path.

8. A fluid injector according to claim 7, wherein, when fluid flow occurs from said first to said second flow path, the fluid pressure acting on the large diameter section D exposed to said first flow path produces a fluid force on said valve greater than that produced thereon by fluid pressure acting on the shoulder of said valve defined between said sections D and d=in conjunction with fluid pressure acting on the smaller diameter section d exposed to said part of said second flow path.

9. A fluid injector according to claim 6, and so constructed that fluid is able to flow through'said injector when said tip sealing valve closes said discharge passage.

10. A fluid injector according to claim 9, wherein said swirl passages provide communication between the two parts of said second path when said tip sealing valve means is in the closure position to provide a fluid flow path through the injector at that time.

11. A fluid injector according to claim 1, including first and second fluid flow passages in communication respectively with the opposite sides of said tip sealing valve, inlet connection port means in permanent communication with said inlet port, and return connection port means in permanent connection with said return port, said changeover valve being operable in a discharge position to connect said inlet connection port means with said first fluid flow passage and, selectively, said second fluid flow passage via said return connection port means with said return port by which to provide a discharge flow path for fluid and, selectively, a return flow path, said changeover valve being operable in a nondischarge position to connect said inlet connection port means with said second fluid flow passage and connect said first fluid flow passage via said return connection port means with said return port by which to provide a flow path through the injector along which fluid can circulate when the injector is in a nondischarge condition.

12. A fluid injector according to claim 11, including a fluid flow passage in the changeover valve which, in a particular nondischarge position of said changeover valve, provides another fluid return flow path direct from said inlet port to said return port.

13. A fluid injector according to claim 12, including second return connection port means in permanent connection with said return port, said second return connection port means having a smaller cross-sectional flow area than said first-mentioned return connection port means, said fluid flow passage in the changeover valve communicating with said return port to provide said direct fluid return path via said second return connection port means.

14. A fluid injector according to claim 13, wherein said fluid flow passage in the changeover valve, in a discharge position of said changeover valve, selectively communicates said second fluid flow passage with said first-mentioned return connection port means to complete said return flow path 15. A fluid injector according to claim 14, wherein said fluid flow passage in the changeover valve, in a particular discharge position of said changeover valve, is out of communication with said first-mentioned return connection port means, at which time the injector is conditioned for a maximum discharge flow through said discharge passage.

16. A fluid injector according to claim 15, wherein said changeover valve is reciprocally slidable into its discharge and nondischarge positions, said changeover valve having a first land operable to connect said inlet connection port means either with said first or second fluid flow passage in depenl dence on the operative position of said changeover valve, said changeover valve having spaced-apart second and third lands defining therebetween a chamber in permanent communication with the fluid flow passage in the changeover valve and selectively communicable with said first-mentioned return connection port means to complete said return flow path or with said second return connection port means to provide said direct fluid return path.

17. A fluid injector according to claim 16, wherein said third land is operable to interfere with said first-mentioned return connection port means to provide a varying restriction to return flow through that port means and hence a variable discharge flow through said discharge passage for a particular supply pressure applied to said inlet port, said third land, in the maximum discharge flow position of said changeover valve, shutting off said first-mentioned return connection port means entirely from said second fluid flow passage to prevent return flow and hence promote said maximum discharge flow.

18. A fluid injector according to claim 16, wherein said second land is positioned between said first and third lands and is operable in a nondischarge position of said changeover valve, when said inlet and return ports are not directly interconnected, to permit communication of said first fluid flow passage with both said first-mentioned and second return con nection port means.

19. A fluid injector according to claim 18, wherein said second land is operable, in the nondischarge position of said changeover valve in which the inlet and return ports are directly interconnected, to permit communication of said first fluid flow passage with said return port via said first-mentioned return connection port means only.

20. A fluid injector according to claim 16, wherein said second land is operable, in a discharge position of said changeover valve, to interrupt communication between said first fluid flow passage and said return port.

21. A fluid injector according to claim 16, wherein said first land is slidably mounted in a tube means defining at least in part said second fluid flow passage, said inlet connection port means being provided in the wall of said tube means.

22. A fluid injector according to claim 21, wherein said first fluid flow passage is defined at least in part by a duct surrounding said tube means and bounded by a barrel of said injector.

23. A fluid injector according to claim 21, wherein said second and third lands are slidably mounted in a second tube means coaxially aligned with said first-mentioned tube means, said first-mentioned and second return connection port means being provided in the wall of said second tube means.

24. A fluid injector according to claim 23, wherein said changeover valve moves forwardly towards said discharge passage in moving from its nondischarge to its discharge position, and vice versa, and a permanent flow path is provided from the rearward side of said third land to said return port to enable, during rearward movement of said changeover valve, any fluid trapped at the rearward side of said third land to pass to said return port.

25. A fluid injector according to claim 24, wherein said permanent path is defined by an annular gap between said second tube means and a rearward barrel section of said injector,

26. A fluid injector according to claim 1, including a power means connected to said changeover valve for selectively mounting said changeover valve into its discharge and nondischarge positions,

27. A fluid injector according to claim 26, including adjustment means for regulating the degree of operative movement available to said power means thereby to regulate the operative positions of said changeover valve.