GB2248285A - Valve system for a fluid injector - Google Patents

Abstract

A valve system for a fluid injector of the type disclosed in GB 2140551 A comprises first and second flow paths 17, 36 each containing a rotary ball valve 9, 8 respectively and connected by a by-pass duct 60. The valve 9 of Figure 6A blocks flow along the duct 60 when the flow path 17 is open and opens the duct 60 when the flow path 17 is closed. In the valve system of Figure 7A, flow along the duct 60 is controlled by pressure responsive valves 104 arranged one in each flow path 17, 36. In Figure 8A (not shown) a valve in the duct 60 is operated via a cam by the drive of the valves 9, 8. In Figure 9A (not shown) a pressure responsive valve, which may be spring biassed, is arranged in the duct 60 so as to permit or prevent throughflow. <IMAGE>

Description

VALVE SYSTEMS The invention relates to valve systems and, in particular, a valve system suitable for a fluid injector and to a fluid injector incorporating such a valve system.

In UK-B-2140551 there is disclosed a tip shut-off fluid injector for an oil burner for a boiler which has its injection device inset to a fixed female interlocking terminal when in the firing position with which a change-over valve is connected by pipes or is made integral. The terminal includes two fluid isolating ball valves and a by-pass valve. A gearbox connects between the three ball valves and a handwheel.

Rotation of the handwheel inserts or retracts the injection device to or from the firing position and also, via the gearbox, rotates the three ball valves between open and closed positions. Before the injection device can be retracted, the handwheel must be initially rotated to rotate the two fluid isolating ball valves to closed positions to isolate the fluid supply from the injection device and to open the by- pass ball valve to allow fluid to circulate from the supply through the female interlocking terminal back to return.

Conversely, it is not until the injection device is inserted that the two fluid isolating ball valves can be rotated by the handwheel to open positions to communicate the fluid supply with the injection device and close the by-pass ball valve. The change-over valve may include a direct flow path interconnecting the fluid supply and return when the injection device is retracted.

Whilst the fluid injector is perfectly satisfactory in use, ball valves are inherently tight in their seats with the result that the operating torque which the operator must apply to the handwheel to rotate the three ball valves between their open and closed position is not inconsiderable.

We have now developed alternative valve systems fulfilling the same function of the two fluid isolating ball valves and the by-pass ball valve system but employing only two ball valves instead of three. By so doing, the advantage is obtained that the operating torque on the handwheel is reduced together with a possible cost saving arising from the elimination of one ball valve.

In order that the invention may be well understood there will now be described some preferred embodiments thereof, given by way of example, with reference to the accompanying drawings, in which: Figures 1A, 1B and 1C are a part-sectioned plan view, side elevation and end elevation, respectively, of a tip shut-off fluid injector as disclosed in UK-B-2140551, secured in the operating position and conditioned for fluid discharge, the injector incorporating a positive mechanical interlock; Figures 2A, 2B and 2C are a part-sectioned plan view, side elevation and end elevation, respectively, of the same fluid injector secured in the operating position but conditioned for non-fluid discharge; Figures 3A, 3B and 3C are a part-sectioned plan view, side elevation and end elevation, respectively, of the same fluid injector with its fluid injection device retracted from the operating position;; Figures 4A and 4B are a fragmentary partsectioned side elevation and end elevation, respectively, of the same fluid injector showing the gearbox and interlocking drive for the positive mechanical interlock thereof, with the gearbox positioned to select the fluid terminal isolating valves to isolate the fluid injection device from the fluid delivery and return circuits; Figures 4C and 4D are views similar to Figures 4A and 4B, respectively, but with the gearbox positioned to select the fluid terminal isolating valves to connect the fluid injection device to the fluid delivery and return circuits; Figures 4E, 4F and 4G illustrate details of the same interlocking drive with the interlocking key thereof in different positions;; Figures 5A, 5B and 5C are a part-sectioned plan view, side elevation and end elevation, respectively of a multi-fluid injector also as disclosed in UK-B-2140551, incorporating a positive mechanical interlock; Figure 5D is a section along line V-V of Figure 5B; Figures 6A, 6B and 6C are sectioned end views of a first valve system embodying the present invention showing the fluid flow paths and the ball valve operating attitudes when used to modify either of the fluid injectors of the preceding figures with the injector secured in the operating position and conditioned for non-fluid discharge, secured in the operating position but conditioned for fluid discharge, and with its fluid injection device retracted from the operating position and in the by- pass mode, respectively;; Figures 7A, 7B and 7C are sectioned end views of a second valve system embodying the present invention showing the fluid flow paths and the valve operating attitudes when used to modify either of the fluid injectors of Figures 1 to 5, with the injector in the modes corresponding to those of Figures 6A, 6B and 6C, respectively; Figures 8A, 8B and 8C are sectioned end views of a third valve system embodying the present invention showing the fluid flow paths and the valve operating attitudes when used to modify either of the fluid injectors of Figures 1 to 5, again with the injector in the modes corresponding to those of Figures 6A, 6B and 6C, respectively; and Figures 9A, 9B and 9C are sectioned end views of a fourth valve system embodying the present invention showing the fluid flow paths and the valve operating attitudes when used to modify either of the fluid injectors of Figures 1 to 5, again with the injector in the modes corresponding to those of Figures 6A, 6B and 6C, respectively.

In the various figures, like references indicate like parts.

Each of the fluid injectors to be described is primarily intended for incorporation in an oil fuel burner suitable for use in a water boiler. Such burners are arranged in the furnace walls of the boiler for firing the boiler's fuel. Oil fuel is used as the prime fuel for firing boilers or as a secondary fuel for igniting coal when that is the primary fuel, or in combination with gas as an alternative primary fuel.

The boiler would generate steam, and have land, marine or other industrial applications.

The tip shut-off fluid injector F of UK-B2140551 shown in Figures 1 to 4 has a considerable degree of similarity to that illustrated in Figures 1 to 7 of UK-B-2080703 but is improved thereover in that it incorporates a positive mechanical interlock the principal features of which are highlighted in UK-B-2140551. Further, the multi-fluid injector F2 of present Figure 5 is similar to that of Figures 9 to 11 of UK-B-2080703 apart from the improvement comprising the positive mechanical interlock.Whilst the present disclosure is believed adequately to disclose the invention now made, attention is directed to UK-B-2080703 for a full and complete disclosure when read in conjunction with UK 1231631, UK 1233317 and UK 1497271 (which are addressed more specifically to the construction and operation of the tip shut-off valve, the change-over valve and a second fluid injector to regulate discharge) the subject matter thereof being incorporated herein by reference.

Referring first to Figures 1 and 2 a fluid injector F of the tip shut-off type has its injection device 1 inset to a female interlocking terminal 2 which is fixed via flanges 3 to an oil burner carrier tube T carrying at its forward end a flame stabiliser S. The carrier tube T is attached to the boiler wall W such that when the injection device 1 is inset to the female terminal 2 the injection device is positioned so as to facilitate discharging fluid into the boiler furnace where it is combusted. This position of the injection device 1 is commonly known as the firing position.

Contrary to UK-B-2080703, a change-over valve 4 of the fluid injector F is not made integral with the female terminal 2 (although it could be if wished), but, rather, two pipes P connect the female terminal with the housing of the changeover valve which, in turn, is connected to fluid delivery 5 and fluid return 6 circuits. The changeover valve 4 is provided to condition the fluid injector F for discharge or nondischarge of fluid.

A terminal valve block 7 houses two fluid terminal isolating valves 8 and 9 and a by-pass valve 10, and is integral with the female terminal 2 to isolate the valves 8 and 9 and to provide automatic circulation of fluid through the fluid injector F from the fluid delivery circuit 5 back to the fluid return circuit 6 when the injection device 1 is retracted from the firing position.

A handwheel 11 is used to insert or retract the injection device 1 to or from the firing position.

The handwheel 11 is keyed to a gearbox 12 which is integral with the valve block 7 and which connects from the handwheel to operate the fluid terminals isolating valves 8 and 9 as well as the by-pass valve 10. Thus operation of the handwheel 11 to position the injection device 1 also selects the fluid terminals isolating valves 8 and 9 for "on" or "off" to facilitate the connection or termination respectively of the fluid supply before the injection device 1 is inserted or retracted. To retract the injection device 1, the gearbox 12 operates so that at the same time as the fluid supply terminates then the by-pass valve 10 opens to allow automatic circulation of the fluid through the terminal valve block 7.

The means employed to key the fluid injector handwheel 11 into the gearbox 12 are arranged in two steps so that operation of the handwheel inserts the injection device 1 to the firing position before opening the fluid terminal isolating valves 8 and 9 to connect the fluid injector to the fluid delivery and return circuits 5 and 6, respectively. Conversely, before the injection device 1 may be retracted from the firing position, the fluid terminal isolating valves 8 and 9 must first be closed. Selection of the fluid terminal isolating valves 8 and 9 to "on" or "off" acts through the gearbox 12 and automatically closes or opens the bypass valve 10.

Two spring operated self closing valves 13 and 14 may be provided in the female interlocking terminal 2 and arranged to close when the injection device 1 is withdrawn thus double isolating the fluid delivery and return circuits 5 and 6.

In Figure 1 the fluid injector F is shown to be in the firing position and conditioned for fluid discharge. Fluid from the fluid delivery circuit 5 enters the changeover valve 4 at a port 5A. The changeover valve 4 is shown selected to the position which conditions the fluid injector F for fluid discharge. With the changeover valve 4 selected to condition the fluid injector F for fluid discharge, the fluid is directed from the port 5 out of the changeover valve through a port 15 and enters the terminal valve block 7 through a port 16. From the port 16, the fluid passes along a duct 17 and through the fluid terminal isolating valve 9 into the female interlocking terminal 2, to the spring operated valve 14 therein. From the valve 14, fluid enters a duct 18 formed in a male interlocking terminal 41 forming part of the injection device 1.The fluid then flows into an annular duct 19 formed between a central tube 20 and an outer tube 21 of the injection device 1. The terminal 41 is made integral with the outer tube 21. From the annulus duct 19, the fluid passes through a tip valve assembly 22 via holes 23 and ducts 24 in a swirl plate 25 into a chamber 26 formed between the swirl plate an an orifice plate 27. Fluid is discharged from the chamber 26 through a hole 28 in the orifice plate 27 to form a finely atomised spray in a region forward of the fluid injector F.

With the fluid injector F so conditioned for fluid discharge, some of the fluid entering the chamber 26 may be returned to the fluid return circuit 6 via a hole 29 in the swirl plate 25 which connects to a chamber 30 next passing via a fluid pressure differential operated tip sealing valve 39 through holes 31, 32 and 33 therein into a chamber 34. From the chamber 34, the fluid flows into the central tube 20 returning via a duct 35 in the male terminal 41 through the spring operated valve 13 and the fluid terminal isolating valve 8 into a duct 36 in the valve block 7 to exit through a port 37 and enter the changeover valve 4 at a port 38. From the port 38, fluid is directed through a passageway P1 in the spool S1 of the changeover valve 4 to discharge into the return circuit 6.

In Figure 2 the fluid injector F is shown to be in the firing position but conditioned for fluid nondischarge. The means to select the fluid injector for fluid non-discharge is provided by the changeover valve 4. It will be seen that the changeover valve spool S1 has been moved rearwardly so that fluid from the fluid delivery circuit 5 enters the changeover valve at the port 5A to be directed out of the changeover valve through the port 38 to enter the terminal valve block 7 through the port 37. From the port 37, the fluid passes along the duct 36 and through the fluid terminal isolating valve 8 to the spring operated valve 13.From the valve 13, the fluid enters the duct 35 and flows into the central tube 20 to act on the rear face of the tip valve 39 which slides as a piston in a cylinder 40 and moves forwardly to close the orifice 28 by making a seal between the forward face of said piston 39 and the rearward face of the orifice plate 27. Some fluid is allowed to flow through the piston 39 via the holes 33, 32 and 31 into the chamber 30 thence to flow through the hole 29 into the chamber 26. From the chamber 26, fluid may return to the fluid return circuit 6 via the ducts 24 in the swirl plate 25 and the holes 23 into the annular duct 19. From the annular duct 19, the fluid flows through the duct 18 and the spring operated valve 14 to the fluid terminal isolating valve 9, and into the duct 17 to leave the terminal valve block 7 through the port 16 and re-enter the changeover valve 4 at the port 15.From the port 15, the fluid is directed through the said changeover valve to discharge therefrom at a port 6A into the return circuit 6.

As will be realised, when the fluid injector F is in the firing position but conditioned for nondischarge, fluid will continuously circulate through it up to the tip valve 39 thereby to cool the forward region of the injection device 1 and obviate the need for it to be retracted away from the boiler interior.

Because of such continuous circulation, fuel cracking and blockage in the injector is obviated, and there is no necessity for cleaning between discharge operations.

By reference to Figure 3, it will be seen that the changeover valve 4 has been selected to condition the fluid injector F for fluid non-discharge and the injection device 1 has been retracted from the firing position.

The injection device 1, as aforesaid, comprises the tip valve assembly 22 and two tubes, a central tube 20 and an outer tube 21, which connect the tip valve assembly to the male interlocking terminal block 41. The central tube 20 is disposed coaxially inside the outer tube 21 to form the annular duct 19 between the two tubes. The handwheel 11 is keyed in permanent rigid connection to a handwheel shaft 42 journalled for rotation in and projecting through the male terminal block 41 and being held captive in said block by the handwheel. The handwheel shaft 42 includes an interlocking key 43 in the form of a drive pin which rotates upon rotation of the handwheel 11. The drive pin 43 extends through and projects radially from the shaft 42 in diametrically opposite directions.The male terminal block 41 includes two guide rods 44 and two male terminals 45 and 46 which connect, respectively, to the ducts 35 and 18. These terminals may contain spring operated self closing valves similar to those provided in the female interlocking terminal 2.

To insert the injection device 1 to the firing position, it is manually lifted by grasping the handwheel 11 to engage the guide rods 44 slidably in matching holes in the female interlocking terminal 2.

The guide rods 44 take the weight of the male terminal block 41 which may then be pushed forward into the female interlocking terminal 2 by disposing the handwheel 11 to permit the interlocking key 43 to enter the female interlocking terminal by insertion in keyways therein defined by two diametrically opposite slots 47 extending from a bore in that terminal which receives the entered handwheel shaft 42. As the injection device 1 moves forward the male terminals 45 and 46 engage slidably mating receiving bores 45a and 45b in the female interlocking terminal 2 and at the position at which they engage the female spring operated self closing valves 13 and 14 the interlocking key 43 passes through the interlocking terminal to enter a slot 48 formed between a land 49 on an integral part of the rearward face of the terminal 2 and between an interlocking shaft 50.The handwheel 11 and the interlocking key 43 are thus engaged in the female interlocking terminal 2 so as to rotate therein.

Figure 4A shows in greater detail the gearbox 12. From this figure it will be seen that to insert the injection device 1 into the female interlocking terminal 2 it is first necessary to engage the interlocking key 43 therein so that it may be rotated. Rotation of the handwheel 11 in a clockwise (facing the handwheel) direction causes the interlocking key 43 to bear on the fixed land 49 which is rising so that as the handwheel rotates the land causes the interlocking key to move from the figure 4E position forwardly along the axis of the female interlocking terminal 2 to insert the injection device 1 to the firing position.As the interlocking key 43 moves forwards it slides into the slot 48 formed between the rising land 49 and the interlocking shaft 50 until as the injection device 1 attains the firing position the interlocking key engages an extension of the slot 48 which is developed into the interlocking shaft to form a drive keyway 51 as shown in Figure 4F. Thus, the injection device 1 is inserted to the female interlocking terminal 2 and located in the firing position and the interlocking key 43 is engaged in the interlocking shaft 50 and bearing on the drive keyway 51 so that further rotation of the handwheel 11 will cause the interlocking key 43 to rotate the interlocking shaft in a clockwise direction as shown in Figure 4G.

The interlocking shaft 50 incorporates a square key 52 at its forward end which is in permanent engagement with a gearwheel 53 which in turn is in permanent engagement with gearwheels 54, 55 and 56 as shown in Figures 4A to 4D. The interlocking shaft 50 is held captive between the female interlocking terminal 2 and the gearbox 12, and the gearwheels 53 to 56 are held captive in the gearbox and arranged in a manner commonly known as a sun and planets arrangement. The gearwheel 53 is the sun gear and the gearwheels 54, 55 and 56 are the planet gears. The planet gears 54, 56 and 55 in turn are respectively in permanent rigid engagement with the fluid terminal isolating valves 8 and 9 and the bypass valve 10 acting through drive members 57, 59 and 58.The gearbox 12 is arranged to connect the planet gear 54 through the drive member 57 to the isolating valve 8, the planet gear 55 connects through the drive member 58 to the by-pass valve 10, and the planet gear 56b connects through the drive member 59 to the isolating valve 9.

Thus, further operation of the handwheel 11...

through an additional 45 degrees ... will rotate the interlocking shaft 50 in a clockwise direction at the same time turning the sun gear 53 which in turn rotates the planet gears 54,55 and 56 to select the fuel terminal isolating valves 8 and 9 to the "on" position thereby connecting the fuel supply and return circuits to the injection device 1 and simultaneously selecting the by-pass valve 10 to the "off" position to close off the automatic circulation through a cross connecting duct 60. Further clockwise rotation of the handwheel 11 is prevented by a fixed pin 61 which projects into a slot 62 cut in the sun gear 53.The fixed pin 61 is fixed to the gearbox 12 and disposed to project into the slot 62 so that rotation of the sun gear 53 is restricted to prevent further rotation of the sun gear when the fuel terminal isolating valves 8 and 9 have been selected for the "on" position. The sun gear 53 is in permanent engagement with the interlocking shaft 50, and the interlocking key 43 is engaged to the interlocking shaft and held in place by the raised part of land 49 on the rearward face of the terminal 2 preventing further clockwise rotation of the handwheel 11, or axial slidable movement of the handwheel. The injection device 1 is thereby inserted to the firing position and locked in place, and by operation of the changeover valve 4 the fluid injector F may be safely selected for fluid discharge or fluid non-discharge.

To retract the injection device 1 from the female interlocking terminal 2, the handwheel 11 is operated to rotate in an anti-clockwise direction.

Turning the handwheel 11 causes the interlocking key 43 to bear on the drive keyway 51 which in turn rotates the interlocking shaft 50 in an anti-clockwise direction.

The interlocking shaft 50 rotates the sun gear 53 which, in turn, rotates its planet gears 54, 55 and 56 to select the fluid terminal isolating valves 8 and 9 to the "off" position and simultaneously selecting the bypass valve 10 to the "on" position thereby automatically causing the fluid to cross-connect from the fluid delivery circuit 5 to the fluid return circuit 6 via the duct 60. Further rotation of the sun gear 53 and interlocking shaft 50 is prevented by the fixed pin 61 bearing on the sun gear through the slot 62. The resistance to the rotation of the sun gear 53 does not prevent the continuing anti-clockwise rotation of the handwheel 11 through a further 45 degrees. The sun gear 53, as previously explained, is in permanent engagement with the interlocking shaft 50, and the pin 61 therefore prevents the interlocking shaft from rotating and at this point the interlocking key 43 disengages from the interlocking shaft. Thus, continued rotation of the handwheel 11 is permitted, and the interlocking key enters the slot 48 formed between the land 49 and the interlocking shaft 50. In anti-clockwise rotation the land 49 is falling and the interlocking key 43 bears on a land 63 which is part of the interlocking shaft 50 causing the injection device 1 to move in a rearward direction along the axis of the female interlocking terminal 2. Further anti-clockwise rotation of the interlocking key 43 is prevented when it is deflected from the slot 48 into the keyways defined by the two slots 47 in the female terminal 2.The injection device 1 may next be retracted or completely removed by grasping the handwheel 11 and pulling the injection device in a rearward direction.

It is important to take the point that before the injection device 1 can be retracted or completely removed from the female interlocking terminal 2, the interlocking shaft 50 must complete its travel as defined by the fixed pin 61 acting in the slot 62 before the interlocking key 43 is deflected from the slot 48 into the keyways defined by the two slots 47 in the female interlocking terminal 2 and which permit the retraction of the injection device because it is this rotation that closes the fluid terminal isolating valves 8 and 9 and these valves must therefore be fully closed before the injection device can be withdrawn.Thus, if a foreign body interposes to prevent the isolating valves 8 and 9 closing then, because the handwheel 11 is in rigid connection to the valve drive members 57 and 59 through the interlocking key 43 and the interlocking shaft 50 and the interlocking key has not completed its rotation, the interlocking key is unable to enter the keyways 47 so that it is not possible to withdraw the injection device 1 from the firing position.

It should also be noted here that the only means available to open the fluid terminal isolating valves 8 and 9 is the interlocking shaft 50, and this can only be operated by the interlocking key 43 which is an integral part of the injection device 1. Thus, the fluid terminal isolating valves 8 and 9 can only be opened with the injection device 1 inset to the firing position and engaged in the female interlocking terminal 2. It is considered that the interlock could only be defeated by special tools requiring special knowledge and skills, and this invention is therefore a significant contribution to operator safety and plant security.

It will now be seen that a positive mechanical interlock has been provided in the fluid injector having the aforementioned features. The fluid injector also has the facility of "automatic circulation": both through the change-over valve spool to allow fuel oil continuously to circulate through the fluid injector from the fuel delivery back to the return circuit and also through the valve block of the female terminal assembly, thereby obviating lengthy dead legs of oil which otherwise could exist to the detriment of the injector on start-up.

Reference to Figures 5A to 5D shows a fluid injector F2 of the multi-fluid kind also with the previously described mechanical interlock. The second fluid, which could be steam, is supplied to the fluid atomiser assembly 22b of the injector device 1b along an annular duct 64 defined between the outer tube 21 and an encompassing tube 65 made fast with the male terminal block. The duct 64 is connected via passages 66, 67 through the male and female terminal assemblies to a steam supply hose 68, and suitable means would be provided, such as a self-sealing valve assembly V, to isolate the steam supply so that it cannot escape from the female terminal when the injection device 1b is withdrawn therefrom.

Whilst, as previously explained the fluid injectors of Figures 1 to 5 are perfectly satisfactory in use, since each embodies the fluid terminal isolating ball valves 8 and 9 and the by-pass ball valve 10, and since inherently ball valves make a tight seal in their seats, an operator must apply a not inconsiderable torque to the handwheel 11 to rotate all three ball valves via the gearbox 12.

The valve systems of Figures 6 to 9 all eliminate one such ball valve and hence not only reduce the operating load on the handwheel 11 but also, in simplifying the gearbox 12, result in a cost saving.

Referring now to Figure 6, the valve system shown therein eliminates the by-pass ball valve 10 whose function is carried out by a modified fluid terminal isolating ball valve 9. Thus, the terminal valve block 7 houses, as before, that ball valve 9 as well as the fluid terminal isolating ball valve 8. The ball valves 8 and 9 rotate in their seats or seals 8a and 9a, respectively, between an open position as shown in Figures 6A and 6B to allow fluid to flow through the ducts 36 and 17, respectively, in the arrowed directions corresponding to the flows shown in Figures 2C and 1C, respectively, that is to say with the fluid injector secured in the operating position and in the recirculating mode, i.e. conditioned for non-fluid discharge, and the firing mode, i.e. conditioned for fluid discharge, respectively, and a closed position as shown in Figure 6C.

The by-pass duct 60 interconnects the ducts 36 and 17. However, when the fluid injector is in either the recirculating or the firing mode, when mounted in the firing position, the ball valve 9, which is also mounted in a valve seat 9c, blocks access from the bypass cct 60, through a port 9d in that seat 9c, to the duct 17.

When the injection device 1 is removed from the female interlocking terminal 2, the ball valves 8 and 9, as explained with reference to Figures 1 to 5, will first have been rotated to their closed position to isolate the fluid supply from the injection device. As will be seen from Figure 6C, when the ball valve 9 is rotated to that closed position, a port 9b in its wall is brought into registry with that part of the duct 17 communicating with the change-over valve, so that fluid may cross-connect from the fluid delivery circuit 5 to the fluid return circuit 6 via the duct 36, duct 60, port 9d, ball valve 9, port 9b and duct 17.

Accordingly, the ball valve 9 serves the dual function of a fluid isolating valve and a by-pass valve.

The mechanism for rotating the ball valves 8 and 9 is as before, i.e. the planet gears 54 and 56, but since the ball valve 10 is eliminated then so is the planet gear 55 thereby simplifying the gearbox 12.

If wished, a restrictor (not shown) may be mounted in the by-pass duct 60 of the valve system of Figure 6.

Referring now to the second valve system shown in Figure 7, each embodies fluid isolating ball valves 8 and 9 as in the fluid injectors of Figures 1 to 5 controlling flow through the ducts 36 and 17, respectively, in the terminal valve block 7 and operated through the gearbox 12. Again, the by-pass ball valve 10 with its attendant planet gear 55 is eliminated.

Instead of the by-pass ball valve 10, a pair of identical Kinghorn type by-pass valves 100 and 101 are provided mounted in counterbored areas 102 of the ducts 36 and 17 in the terminal valve block 7, the bypass duct 60 interconnecting the counterbores 102.

Each Kinghorn type by-pass valve 100, 101 comprises a terminal 103 and a valve cup 104 whose head includes a fluid passage 105, a coil compression spring 106 being mounted between the terminal and the valve cup to bias them apart from one another.

In the firing mode of the fuel injector shown in Figure 7A, the supply flow of fluid through the duct 17 via the open ball valve 9 will urge the valve cup 104 of the by-pass valve 101 away from its terminal 103 (in conjunction with the spring bias) until the valve cup seats in the inner end of the counterbore 102. At the same time, the return flow of fluid into the duct 36 will close the valve cup of the by-pass valve 100 against its terminal 103. In so doing, the peripheral wall of the valve cup 104 will close off communication between the by-pass duct 60 and the counterbored section of the duct 36.In the recirculating mode of the fluid injector shown in Figure 7B, the opposite will occur, that is to say the valve cup 104 of the by-pass valve 101 will close against its terminal 103, thereby to block off communication between the by-pass duct 60 and the counterbored section of the duct 17, under the pressure of the return flow of fluid, whilst the valve cup 104 of the by-pass valve 100 is opened with respect to its terminal 103. In either case, a by-pass flow of fluid through the terminal block 7 is prevented.

When the ball valves 8 and 9 are rotated to their closed position as shown in Figure 7C preparatory to retraction of the injection device 1, since the supply pressure applied through the duct 36 is isolated from the injection device 1 by the closed ball valve 8, the fluid supply flow in the duct 36 will cease and the bias of the spring 106 will urge the valve cup 104 of the by-pass valve 100 away from its terminal 103 to intercommunicate the counterbored section of the duct 36 with the by-pass duct 60. Supply pressure will then flow via the by-pass duct 60 into the counterbored section of the duct 17, the Kinghorn type by-pass valve 101 having opened under the influence of its biasing spring 106.Thus, a fluid cross-connection from the fluid delivery circuit 5 to the fluid return circuit 6 will occur automatically upon rotational closure of the two fluid isolating ball valves 8 and 9 under the control of the Kinghorn type by-pass valves 100, 101.

Again, a restrictor 107 may be incorporated in the bypass duct 60.

In the third valve system depicted in Figure 8, yet again there is provided a pair of fluid isolating ball valves 8 and 9 serving the same function and operated by the same means as in the fluid injectors of Figures 1 to 5. This time, instead of the provision of a third by-pass ball valve to control recirculation through the terminal valve block 7, there is provided a mechanically operated by-pass valve 108.

The valve 108 comprises a terminal 109 screwed into the valve block 7 as far as, but not beyond the bypass duct 60 interconnecting the ducts 36 and 17 through which fluid flow is controlled, as before, by the rotational position of the ball valves 8 and 9 in conjunction with the change-over valve. The by-pass valve 108 also includes a cup shaped valve member 110 with a coil compression spring 111 mounted between the terminal 109 and that valve member.

The gearbox shaft 50 incorporates an integral cam 112 which, when the injection device 1 is inset to the interlocking terminal and with the fuel injector in the firing mode as shown in Figure 8A or the recirculating mode as shown in Figure 8B will engage the valve member 110 to urge it against the bias of the spring 111 against the terminal 109 by which the peripheral wall 113 of the valve member, which is guided in an extension of a counterbore 114 in which the terminal is mounted, will block off communication between those areas of the by-pass duct 60 running into the counterbore 114. Thereby, recirculation through the valve block 7 at that time is prevented.

When the injection device 1 is retracted, the ball valves 8 and 9, as before, have their rotational closed position relative to their ducts 36 and 17, respectively, as shown in Figure 8C, and the gearbox shaft 50 has been rotated to clear the cam 112 from the extension 115 of the valve member 110 against which it previously engaged to close that valve member as described, whereupon the spring 111 will bias the valve member away from the terminal 109 so that its peripheral wall 113 clears the junctions of the by-pass duct 60 with the counterbore 114 so allowing a by-pass fluid flow through the valve block 7. Again, a restrictor 107 may be provided in the by-pass duct 60.

Finally, the fourth valve system depicted in Figure 9 again incorporates a pair of fluid isolating ball valves 8 and 9 controlling flow through the ducts 36 and 17, respectively, as described in relation to the fluid injector of Figures 1 to 5 and under the control of the same gearbox mechanism as featured therein.

However, instead of a third by-pass ball valve, there is provided a hydraulically operated by-pass shuttle valve 116.

As shown in Figure 9A, when the injection device 1 is inset and the fluid injector is in the firing mode, the shuttle valve 116 will be urged by the supply pressure exerted through the duct 17 and the associated region of the by-pass duct 60 against the pressure restrictor 107 to seal off the by-pass duct and so prevent a by-pass flow therethrough from the duct 17 to the duct 36.

When the injection device l is inset and the fluid injector is in the recirculating mode as shown in Figure 9B, the supply pressure exerted through the duct 36 and the pressure restrictor 107 will urge the shuttle valve 116 away from that restrictor until it engages a shoulder 117 in the duct 60. Accordingly, unlike the previous valve systems described herein, a by-pass flow will occur through the duct 60 from the duct 36 to the duct 17 via channels in the arrowhead 118 of the shuttle valve 116. Alternatively, a coil compression spring (not shown) could be located between the shoulder 117 and the shuttle valve 116 to urge the shuttle valve against the pressure restrictor 107 to block off a bypass flow at that time.

Removal of the injection device and with the fluid injector in the by-pass mode as shown in Figure 9C will result again in the supply pressure applied through the duct 36 and restrictor 107 urging the shuttle valve 116 to the right as before thereby again promoting a recirculating flow through the valve block 7. The supply pressure would be sufficient to overcome the bias of the coil compression spring if incorporated between the shoulder 117 and the shuttle valve 116.

Whilst the various first, second, third and fourth valve systems have been described in the environment of a fluid injector, those skilled in the art will appreciate that uses thereof in other environments are possible.

An oil burner incorporating any of the fluid injectors as described would also have an air register to provide the combustion air, valves to regulate and shut off the air and fuel supplies and an igniter to initiate combustion.

Claims (31)

1. A fluid injector comprising an injection device; fluid connection means fluidly connecting said injection device to a fluid delivery line external to said fluid injector; said injection device being removably mounted relative to said fluid connection means; valve means for controlling fluid communication between said fluid connection means and said injection device; actuator means, first initial rotary movement of which selectively rotates said valve means to an isolate position so as to fluidly isolate said fluid connection means from said injection device, first continued rotary movement of which in the same rotary direction effects removal of said injection device from said fluid connection means, said first continued rotary movement to effect said removal of said injection device being possible only after completion of said first initial rotary movement to rotate said valve means to said isolate position, second initial rotary movement of which in the opposite rotary direction effects insertion of said injection device relative to said fluid connection means to an operating position, second continued rotary movement of which in said opposite rotary direction rotates said valve means to a position at which said valve means fluidly communicates said fluid connection means with said injection device, said second continued rotary movement to rotate said valve means to its said position at which to fluidly communicate said fluid connection means and said injection device being possible only after completion of said second initial rotary movement to effect said insertion of said injection device to its said operating position; said fluid connection means comprising a flow control valve having a fluid inlet port adapted for connection to said fluid delivery line and a fluid return port adapted for connection to a fluid return line, said flow control valve permitting selective discharge of fluid from said injection device when said injection device is in said operating position; said injection device including a discharge passage and a tip valve for controlling discharge through said discharge passage, said flow control valve being movable into one position to condition said tip valve to permit fluid discharge through said discharge passage and into another position to condition said tip valve to close said discharge passage at which time said injection device will accept a continuous circulation of fluid through itself, said flow control valve in being moved between its said positions changing within said fluid injector the direction of flow of fluid supplied thereto from said inlet port, said conditioning of said tip valve being directly brought about by a reversible fluid pressure differential within said injection device the mode of which is determined by the direction of the fluid flow as controlled by said flow control valve; a fluid coupling device comprising a pair of terminals, one of which constitutes a stationary member of said fluid connection means and the other of which is fast with said injection device, said other terminal rotatably supporting said actuator means, said one terminal supporting said valve means, said other terminal including first flow path means communicating with said injection device, said one terminal including second flow path means for fluid connection with said fluid connection means, said valve means being interposed in said second flow path means to seal off or open same when in said isolate or communicate positions, respectively, said first and second flow path means communicating with each other when said injection device is in said operating position; said first flow path means comprising first and second flow paths communicating with first and second ducts, respectively, in said injection device, said second flow path means comprising further first and second flow paths, said first and second flow paths of said other terminal being matched with said first and second flow paths of said one terminal, said flow control valve in one of its said positions causing fluid to flow from said inlet port through said matched first flow paths into said first duct towards said discharge passage, said flow control valve in the other of its said positions causing fluid to flow from said inlet port through said matched second flow paths into said second duct to return via said first duct and said matched first flow paths into said return port; said valve means comprising a pair of ball valves each interposed in one of said first and second flow paths in said one terminal to seal off or open same when in said isolate or communicate positions, respectively; and a by-pass valve system comprising a duct interconnecting said first and second flow paths in said one terminal and by-pass valve means controlling flow between said first and second flow paths in said one terminal through said duct, said by-pass valve means comprising: (a) one of said ball valves which when said ball valves are in said communicate position blocks fluid access through said duct between said first and second flow paths in said one terminal and which when said ball valves are in said isolate position permits a by-pass flow of fluid through said duct between said first and second flow paths in said one terminal; or (b) a pair of valve members each interposed in one of said first and second flow paths in said one terminal, one of said valve members when said ball valves are in said communicate position and said flow control valve is in its said one position permitting fluid communication between its respective flow path and said duct but the other of said valve members at that time blocking fluid communication between its respective flow path and said duct so preventing a by-pass flow of fluid through said duct, said other valve member when said ball valves are in said communicate position and said flow control valve is in its said other position permitting fluid communication between its respective flow pcth and said duct but said one valve member at that time blocking fluid communication between its respective flow path and said duct so again preventing a by-pass flow of fluid through said duct, and both said valve members when said ball valves are in said isolate position permitting fluid communication between their respective flow paths and said duct so permitting a bypass flow of fluid through said duct; or (c) a valve member having a path of movement laterally across said duct, which is spring biased clear of said duct to allow a by-pass flow of fluid therethrough between said first and second flow paths in said one terminal when said ball valves are in said isolate position, and which is urged against that spring bias into said duct to block the by-pass flow of fluid therethrough when said ball valves are in said communicate position by rotatable cam means whose rotary movement is controlled by said rotary movement of said actuator means; or (d) a valve member having a path of movement longitudinally along said duct, which is urged by fluid pressure in said duct when said ball valves are in said communicate position and when said flow control valve is in said one position into sealing engagement with a valve seat to block a by-pass flow of fluid through said duct between said first and second flow paths in said one terminal, and which is urged in the opposite direction by fluid pressure in said duct when said ball valves are in said isolate position away from said valve seat to permit a by-pass flow of fluid through said duct between said first and second flow paths in said one terminal.

2. A fluid injector as claimed in claim 1, wherein said one ball valve is the ball valve interposed in the first flow path in said one terminal, said ball valves having through passages therein to permit flow through their respective flow paths when in said communicate position, said one ball valve having a port therein which when that ball valve is in its said communicate position is sealed against a valve seat but which when said one ball valve is rotated to its said isolate position communicates one end of the by-pass duct via the through passage in said one ball valve with said first flow path, the other end of said by-pass passage being in permanent communication with said second flow path in said one terminal.

3. A fluid injector as claimed in claim 1, wherein each valve member of the pair of valve members is spring biased in its respective flow path to a position in which to permit fluid communication between that flow path and said by-pass duct and are both held in that open position when said ball valves are in said isolate position, the valve member in the first flow path in said one terminal opening to permit fluid communication between one end of said by-pass passage and that first flow path when said ball valves are in said communicate position and said flow control valve is in said one position, the valve member in the second flow path in said one terminal at the same time being urged by return fluid in that flow path against the spring bias to block off fluid communication between that second flow path and the by-pass duct, and vice versa when said flow control valve is in said other position with the ball valves in said communicate position.

4. A fluid injector as claimed in claim 1 or claim 3, wherein the pair of valve members are Kinghorn type valves.

5. A fluid injector as claimed in claim 1, wherein said valve member of (c) is urged by said cam means against its spring bias into its interrupting position across said by-pass duct both when said flow control valve is in its said one and said another positions with said ball valves in said communicate positions.

6. A fluid injector as claimed in claim 1, wherein said valve member of (d) is urged by said fluid pressure in said by-pass duct into said sealing engagement with its seat to block a by-pass flow of fluid through said by-pass duct when said ball valves are in said communicate position with said flow control valve in its said one position but not when said ball valves are in said communicate position with said flow control valve in its said other position thereby permitting a by-pass flow of fluid at that time between the first and second flow paths in said one terminal.

7. A fluid injector as claimed in any of the preceding claims, including a gear train between said valve means and said actuator means, said gear train being rotatable in response to said first-mentioned initial and second continued movements of said actuator means to rotate said valve means to its isolate and communicate positions, respectively.

8. A fluid injector as claimed in claim 7, including cam track and associated cam follower means which are caused to make relative movement in response to said first-mentioned continued and said second initial movements of said actuator means to effect said removal and insertion, respectively, of said injection device from and to its said operating position.

9. A fluid injector as claimed in claim 8, wherein said cam follower means is fast with a shaft which is rotatable by said actuator means which comprises a handwheel, said shaft being axially fast with said injection device, and wherein said cam track means is fashioned on said stationary member and is so configured that rotation of said handwheel causes said cam follower means as it rotates to move axially thereby inserting said injection device to, or removing said injection device from, said operating position in dependence on the sense of rotation of said handwheel.

10. A fluid injector as claimed in claim 9, wherein said cam track means leads into a slot formed in a second shaft and into which said cam follower means slides as said handwheel completes its second initial rotary movement to effect insertion of said injection device to its operating position, said second shaft being in driving engagement with said gear train, said second continued rotary movement of said handwheel engaging said cam follower means with said slot to rotate said second shaft and hence said gear train in the sense to rotate said valve means to its communicate position, said first-mentioned initial rotary movement of said handwheel engaging said cam follower means with said slot to rotate said second shaft and hence said gear train in the opposite sense to rotate said valve means to its isolate position, said cam follower means sliding from said slot as said handwheel completes its said first-mentioned initial rotary movement to be engaged with said cam track means to effect removal of said injection device from its operating position as said handwheel executes its said first-mentioned continued rotary movement.

11. A fluid injector as claimed in claim 10, wherein said cam follower means is a drive pin projecting radially from said first-mentioned shaft in diametrically opposite directions, each radial projection of said drive pin being engageable with an associated said cam track means and slot.

12. A fluid injector as claimed in claim 11, wherein said stationary member has diametrically opposed keyways therein extending from a bore receiving said handwheel shaft and for receiving and guiding said drive pin to and from said cam track means as said injection device is removably mounted relative to said fluid connection means.

13. A fluid injector as claimed in any of claims 9 to 12, wherein said other terminal rotatably supports said handwheel shaft, and wherein said one terminal supports said gear train means and said second shaft.

14. A fluid injector as claimed in any of claims 7 to 13, wherein said ball valves are interconnected by said gear train with said actuator means.

15. A fluid injector as claimed in claim 14, wherein said gear train comprises a sun gear drivingly connected with said second shaft and planet gears each drivingly connected with one said ball valve.

16. A fluid injector as claimed in claim 15, including means for restricting rotation of said sun gear beyond extreme positions at which in one sense of rotation said ball valves are in said isolate position and in the opposite sense of rotation said ball valves are in said communicate position.

17. A fluid injector as claimed in any of the preceding claims, wherein said one terminal includes valve means self-actuated to closure to seal off said second flow path means when said terminals are disconnected from each other upon removal of said injection device from said operating position, said self-actuated to closure valve means being urged open when said terminals are interconnected upon insertion of said injection device to said operating position to open said second flow path means.

18. A fluid injector as claimed in claim 17, wherein said other terminal includes second valve means self-actuated to closure to seal off said first flow path means when said terminals are disconnected from each other upon removal of said injection device from said operating position, said first-mentioned and said second self-actuated to closure valve means urging each other open when said terminals are interconnected upon insertion of said injection device to said operating position to communicate said first and second flow path means with each other.

19. A fluid injector as claimed in any of the preceding claims, wherein said flow control valve provides a direct flow path through itself intercommunicating said inlet and return ports when said injection device is removed from said operating position by which fluid delivered through said inlet port may circulate through said direct flow path to return into said return port.

20. A fluid injector as claimed in any of the preceding claims, wherein said flow control valve is connected by pipe means with said one terminal.

21. A fluid injector as claimed in any of claims 1 to 19, wherein said flow control valve is made integral with said one terminal.

22. A fluid injector as claimed in any of claims 19 to 21, wherein said flow control valve comprises a housing having said inlet and return ports and a valve spool linearly movable in said housing to control the direction of fluid within said fluid injector, said direct flow path comprising a passage in said valve spool.

23. A fluid injector as claimed in any of the preceding claims, wherein said one terminal is adapted for connection to a second external fluid delivery line to enable the use of a second fluid to regulate discharge through said discharge passage, said terminals including cooperating valves for communicating the second fluid delivery line with said injection device when said terminals are interconnected and for isolating the second fluid delivery line from said injection device when said terminals are disconnected.

24. A valve system comprising first and second flow paths, a pair of ball valves each interposed in one of said flow paths and each rotatable between isolate and communicate positions respectively to seal off and open the respective flow path, a duct interconnecting said first and second flow paths, and by-pass valve means for controlling flow between said first and second flow paths through said duct; said by-pass valve means comprising: (a) one of said ball valves which when said ball valves are in said communicate position blocks fluid access through said duct between said first and second flow paths and which when said ball valves are in said isolate position permits a by-pass flow of fluid through said duct between said first and second flow paths; or (b) a pair of valve members each interposed in one of said first and second flow paths, one of said valve members when said ball valves are in said communicate position and when fluid flows in a first direction through said flow paths permitting fluid communication between its respective flow path and said duct but the other of said valve members at that time blocking fluid communication between its respective flow path and said duct so preventing a by-pass flow of fluid through said duct, said other valve member when said ball valves are in said communicate position and when fluid flows in the opposite direction through said flow paths permitting fluid communication between its respective flow path and said duct but said one valve member at that time blocking fluid communication between its respective flow path and said duct so again preventing a by-pass flow of fluid through said duct, and both said valve members when said ball valves are in said isolate position permitting fluid communication between their respective flow paths and said duct so permitting a by-pass flow of fluid through said duct; or (c) a valve member having a path of movement laterally across said duct, which is spring biased clear of said duct to allow a by-pass flow of fluid therethrough between said first and second flow paths when said ball valves are in said isolate position, and which is urged against that spring bias into said duct to block the by-pass flow of fluid therethrough when said ball valves are in said communicate position by rotatable cam means; or (d) a valve member having a path of movement longitudinally along said duct, which is urged by fluid pressure in said duct when said ball valves are in said communicate position and when fluid flows in one direction through said flow paths into sealing engagement with a valve seat to block a by-pass flow of fluid through said duct between said first and second flow paths, and which is urged in the opposite direction by fluid pressure in said duct when said ball valves are in said isolate position away from said valve seat to permit a by-pass flow of fluid through said duct between said first and second flow paths.

25. A valve system as claimed in claim 24,wherein said one ball valve is the ball valve interposed in the first flow path, said ball valves having through passages therein to permit flow through their respective flow paths when in said communicate position, said one ball valve having a port therein which when that ball valve is in its said communicate position is sealed against a valve seat but which when said one ball valve is rotated to its said isolate position communicates one end of the by-pass duct via the through passage in said one ball valve with said first flow path, the other end of said by-pass passage being in permanent communication with said second flow path.

26. A valve system as claimed in claim 24, wherein each valve member of the pair of valve members is spring biased in its respective flow path to a position in which to permit fluid communication between that flow path and said by-pass duct and are both held in that open position when said ball valves are in said isolate position, the valve member in the first flow path opening to permit fluid communication between one end of said by-pass passage and that first flow path when said ball valves are in said communicate position and fluid flows in a first direction through said flow paths, the valve member in the second flow path at the same time being urged by return fluid in that flow path against the spring bias to block off fluid communication between that second flow path and the by-pass duct, and vice versa when fluid flows in the opposite direction through said flow paths with the ball valves in said communicate position.

27. A valve system as claimed in claim 24 or claim 26, wherein the pair of valve members are Kinghorn type valves.

28. A valve system as claimed in claim 24, wherein said valve member of (c) is urged by said cam means against its spring bias into its interrupting position across said by-pass duct both when fluid flows in said one and in the opposite direction through said flow paths with said ball valves in said communicate position.

29. A valve system as claimed in claim 24, wherein said valve member of (d) is urged by said fluid pressure in said by-pass duct into said sealing engagement with its seat to block a by-pass flow of fluid through said by-pass duct when said ball valves are in said communicate position with fluid flow occurring in a first direction through said flow paths but not when said ball valves are in said communicate position with fluid flow in the opposite direction through said flow paths thereby permitting a by-pass flow of fluid at that time between the first and second flow paths.

30. A fluid injector substantially as herein described with reference to Figures 1 to 4, or Figure 5 of the accompanying drawings and incorporating a valve system substantially as herein described with reference to Figure 6, or Figure 7, or Figure 8, or Figure 9 of the accompanying drawings.

31. A valve system substantially as herein described with reference to Figure 6, or Figure 7, or Figure 8, or Figure 9 of the accompanying drawings.