HOT GAS DIVERTER VALVE

Abstract: A hot gas diverter valve has a delivery duct (17) for directing a hot gas flow along a first axis (X-X), a diverter duct (28) with an inlet (29) for accepting hot gas flow and directing it to either side of the axis (X-X) two receiver ducts (19, 20) angularly situated one on each side of the axis (X-X) to receive flow proportionally or selectively from the diverter duct (28), the diverter duct (28) being pivoted about a second axis (Y-Y) which lies both normal to the first axis (X-X) and coincident with the inlet (29).

Description: - 1 - Title: Hot Gas Diverter Valve. This invention relates to valves for the diversion of a hot gas flow from a single duct selectively and/or proportionally to a plurality of ducts. Such valves may typically be used in a flight vehicle where hot gas from a source (for example the burning propellant of a propulsion engine) is used to power an actuator (for example in the vehicle control system) . In such and similar embodiments the valves are liable to become clogged or damaged by the deposition of contaminents that occur in the hot gas, they are liable to be damaged by the high temperatures involved; and they are liable to sealing problems. The present invention has for an objective a valve in which the incidence of problems due to these liabilities is at least reduced. According to the present invention a hot gas diverter valve includes a delivery duct with an outlet for directing a hot gas flow along a first axis, a diverter duct with an inlet for accepting hot gas flow from the outlet of the delivery duct and an outlet for directing flow either along the first axis or to either side thereof, a plurality of receiver ducts having inlets positioned to receive flow from the outlet of the diverter duct, and pivot means positioned to allow pivoting of the diverter -BUREAU OMPI - - W1P0 ,Λ>, duct about a second axis transverse to the first axis i the region of the inlet to the diverter duct. Preferably the second axis is normal to the first axis and is coincident with or just upstream of said in Preferably the diverter duct is pivoted and carri by motor driven drive shaft means. A preferred embodiment of a valve according to th invention is described with reference to the accompanyi drawings in which:- ' Figure 1 is a diagram of a known diverter valve installatio , Figure 2 is a side view of a preferred valve bein partly sectioned upon line II-II of figure 3, Figure 3 is a plan view of the preferred valve be partly sectioned upon line III-III of Figure 2 , and, Figure 4 is an end view. Referring initially to Figure 1 fluid is ducted f a source (not shown) , along a delivery duct 1. This delivery duct is in flow communication with diverter du having an outlet 3. The outlet 3 is shifted laterally either side of a central axis X-X by means of a motor 4 a region of the diverter duct 2 being flexible to allow such shifting. The outlet 3 discharges into twin inlets 5 and 6, receiver ducts 7 and 8, respectively, angularly situate on each side of the axis X-X. Naturally, when the outl of the diverter duct lies on the X-X axis the fluid flow is shared between the ducts 7 and 8 and when shifted under the action of the motor 4 is progressively proportional until the situation is such that the full flow is directed selectively to the duct 7 or the duct 8. The ducts 7 and 8 are in flow communication with piston/cylinder arrangements 9 and 10, respectively, the pistons of which are coupled to a pivoting beam 11. Differential movement of the pistons under the action of the fluid flow effects rotation of the beam 11 and hence actuation of control apparatus, not shown. The flexible region of the diverter duct can be replaced with a knuckle joint. It has been found that both the flexible region and the knuckle joint arrangements have disadvantages in practice when the fluid is a hot gas, for example that derived from the solid propellant charge of a rocket motor. Since the gas flow is at high temperature a truly flexible region is liable to melt, whilst, if made of a heat resistant material it is found to be insufficiently flexible to give accurate and rapid flexing under the action of the motor. Similarly, a knuckle joint arrange¬ ment which requires seals between the moving portions of knuckle is found to be susceptible to seal failure. Referring now to Figures 2, 3 and 4, a diverter valve according to the invention is illustrated as an assembly including a piston/cylinder arrangement in the jUREA T O PI - 4 - form of a double acting piston rather than the twin piston arrangement of Figure 1; it accordingly does not include the beam 11. The piston/cylinder arrangement do not form part of the invention. In the Figures the valve itself has a body portion with a cylindrical bore 13 formed along an axis referenc X-X. Inserted into this bore from the right hand end, drawn, is a delivery duct member 14, and from the left h end, as drawn, is a receiver duct member 15. Both memb are electron beam welded into position leaving a chamber in between. The delivery duct member 14 has a delivery duct 17 formed through it with an outlet 18 lying in a plane nor to the axis X-X. Both the duct 17 and the outlet 18 lie upon the axis X-X. The duct 17 accepts hot gas from a source, not shown. The receiver duct member 15 has receiver ducts 19 and 20 which are symmetrically disposed in a lateral pla with respect to the axis X-X and are angled from it. Th ducts respectively have inlets 21 and 22 which abut on th axis X-X and lie in a common plane normal to that axis. The ducts 19 and 20 are in flow connection with opposed sides of a piston 23, shown in broken outline in Figures 3 and 4, housed in a cylinder block 24 carried up a protruding portion of the receiver duct member 15. The piston is carried upon an actuator rod 23a. Between the member 14 and the member 15 lies a diverter duct member 25. This is carried upon a shaft 26 which is rotatable about an axis Y-Y lying normal to and coincident with the axis X-X. The shaft 26 is carried and driven by a motor 27 which is itself carried upon the body portion 12. That part of the diverter duct member 25 lying between the outlet 18 and the inlets 21 and 22 (that is to say, in the chamber 16) is of cylindrical form with the major axis of the cylinder lying parallel to the Y-Y axis, that is to say offset from it in a generally downstream direction. Extending through this cylindrical portion and concentric with the axis X-X when in an undisturbed state is a diverter duct 28 which has an inlet 29 arranged to receive gas flow from the outlet 18 and an outlet 30 arranged to deliver gas flow to the inlets 21. and 22. The radius of the cylindrical portion is chosen so as to position the inlet 29 substantially in the region of the Y-Y axis. Preferably, as drawn, it lies on the Y-Y axis and the outlet 18 is slightly spaced upstream from the surface of the cylinder. Similarly, the inlets 21 and 22 are slightly spaced downstream from the surface of the cylinder. As shown, the outlet 18 is of similar diameter to the inlet 29 and the outlet 28 is of similar diameter to the inlet 29 but is smaller than the diameters of the inlets 21 and 22. Exhaust gas flow is through the chamber 16 and an exhaust duct 31. - uREvT } OMPI The described arrangement has advantage in that the diverter duct member 25 can be rotated without the frictio associated with closely contacting components, there is found to be only small gas flow loss due to clearances sinc the inlet 29 always remains close to the outlet 18, and gas through flow and contaminent deposition tolerance is aided by use of induced flow from the exhaust gas in the chamber 16; it is found that the cylindrical shape of the diverter duct member 25 helps in this latter respect. To reduce ablation those surfaces in contact with the hot gases may be treated with, for example, a borided alloy of titanium, zirconium, and molybdenum. OMP

Claims: - 7 - What we claim is : - 1. A hot gas diverter valve including a delivery duct with an outlet for ' delivering a hot gas flow along a first axis, a diverter duct with an inlet for accepting hot gas flow from .the outlet of the delivery duct and an outlet for directing flow either along the first axis or to either side thereof, a plurality of receiver ducts having inlets positioned to receive flow from the outlet of the diverter duct, and pivot means positioned to allow pivoting of the diverter duct about a second axis transverse to the first axis in the region of the inlet to the diverter duct. 2. A hot gas diverter valve according to claim 1 wherein the second axis is normal to the first axis and lies coincident with the. inlet to the diverter duct. 3. A hot gas diverter valve according to claim 1 or claim 2 wherein the diverter duct is pivoted and carried by motor driven drive shaft means. 4. A hot gas diverter valve according to any one of the previous claims wherein the diverter duct is formed in a cylindrical diverter duct member the major axis of the cylinder lying parallel to and downstream of the second axis. 5. A hot gas diverter valve according to claim 4 wherein the second axis is coincident with the cylindrical surface of the diverter duct member. 6. A hot gas diverter valve according to claims 4 or 5 wherein the outlet of the delivery duct and the inlets of the receiver ducts are close to but do not touch the cylindrical - OR A L OIΛPϊ < » surface of the diverter duct member. 7. A hot gas diverter valve according to any one of the previous claims wherein the outlet of the delivery duct, the inlet and the outlet of the diverter duct are of similar diameter, but the inlets of the receiver ducts are of a larger diameter. 8. A hot gas diverter valve substantially as described with reference to Figures 2, 3 and 4 of the accompanying Figures. _ O

Inventors: HALL R, HEATH M, MONK B
Applicants: BRITISH AEROSPACE
Application year: 1979
Main classification: F16K11
IPC codes: F15C3