GB2261932A - Seal - Google Patents

Abstract

An abutment seal comprises a length of channel section 1 from which protrudes a resiliently mounted seal member 8. The seal member has a top hat cross-section the nose, or crown, of which protrudes through the elongate opening of the channel. The lower margins of the seal member are bent outwardly to retain it within the channel housing. Adjacent lengths of seal assembly may be interconnected by spring loaded plungers 12 fitted inside adjacent ends to join them together and to prevent a leakage path. The spring loading is provided by leaf springs integral with the plunger. The seal member, channel section and springs are all preferably of metal. The seal may be used on a butterfly or gate valve in a vectored thrust gas turbine engine. <IMAGE>

Description

SEAL This invention relates to fluid sealing assemblies and in particular to fluid sealing assemblies of the kind used to prevent the leakage of fluid past a displaceable closure member in a fluid flow duct.

In fluid flow ducts wherein the fluid is at a relatively high temperature such as is to be found in the so-called vectored thrust arrangements of vertical--short take-off and landing aircraft where a proportion of the exhaust gases from a gas turbine engine may be diverted from the engine exhaust pipe into swivellable nozzles for conversion from forward thrust into vertical lift, the ducting carrying the hot gases is subject to high temperature as well as vibration and flexure and sealing arrangements for valves in ducting of this kind is required to be capable of withstanding such adverse conditions.

According to one aspect of the present invention a seal assembly comprises a substantially hollow housing member having an elongated opening through a wall of the housing, an elongated sealing member housing a body portion for locating within the housing and a nose portion for projecting through the elongated opening, and resilient means whereby the nose portion of the sealing member is urged outwardly through the elongated opening of the housing member.

Preferably the housing member is of rectangular bo section having an elongated slot extending from end-to-end of one side wall, and the sealing member is of top-hat section the rim of which together with the side walls of the elongated slot prevent the sealing member from being ejected from the housing member by the resilient means. The resilient means may comprise a plunger of an elastic material or may comprise metal plunger from which extend leaf springs which may be integral with the plunger. Or the resilient means may comprise a metal plunger provided with a recess in its underside to receive a compression spring.

According to another aspect of the invention a seal assembly comprises a substantially hollow box-like housing member having an elongated opening in one wall at least two elongated sealing members each having a body portion and a nose portion, and resilient means whereby when the sealing members are located in end-to-end relationship within the housing member the nose portions of the sealing members are maintained extended outwardly through the elongated opening in the housing member.

Preferably the resilient means includes a plurality of plungers each closely fitting within a recess in the sealing members and extending across the junction of two adjacent sealing members, and springs to urge the plungers into the recess. Both the plungers and the springs may be of metal.

In one arrangement according to the invention the plungers are provided with leaf springs extending from and integral with the plungers. In another arrangement the plungers may be provided with a recess to receive compression springs.

In certain circumstances such as when seal assemblies according to the present invention are employed in the fluid ducting of gas turbine engines a source of high pressure gas may be tapped and the gas directed to the interior of the sealing members so as to assist the resilient means.

According to a further aspect of the invention a sealing arrangement is provided for a valve wherein a seal assembly of the present invention is arranged to act between a fixed seat of the valve and a member displaceable relative to that seat.

According to a still further aspect of the invention there is provided a sealing arrangement for a valve controlling the distribution of fluid flow in a gas turbine engine wherein a seal assembly of the kind described herein is arranged to act between a fixed seat of the valve and a member displaceable relative to that seat, the valve being located in a fluid flow duct.

Such valves are to be found in certain aircraft of the vertical/short take-off and landing type where fluid is directed as required from a main fluid flow duct into one or more ducts supplying swivellable lift nozzles.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows, in perspective, a seal assembly with the housing member, sealing strip member and spring means in working arrangement, Figure 2 shows a longitudinal section through the seal assembly shown in Figure 1, Figure 3 shows a cross-section on the line A-A through the seal assembly shown in Figures 1 and 2, Figure 4 illustrates partly in section the seal assembly shown in Figures 1, 2 and 3 as applied to one embodiment of the invention employing a rotary valve, Figure 5 shows the seal assembly shown in Figures 1, 2 and 3 as applied to a second embodiment of the invention employing a slide valve, the valve being shown in its open position, and Figure 6 shows the seal assembly shown in Figure 5 with the valve shown in its closed position.

Referring to the drawings the seal assembly shown in Figures 1 to 3 includes a metal channel-section housing member 1 having a base 2 whereby the housing member may be secured to a surface as by rivets (not shown). The housing member 1 also has a pair of side walls 3,4 upstanding from the base and the upper margins 5,6 of which turn towards each other to define an elongate opening 7.

A sealing strip 8 of metal sheet formed into a top hat section is retained within the channel section. It ha a nose portion 9 which projects through opening 7. The edges of the strips are bent outwardly at 10,11 to comprise flanges which retain the strip within the housing member 1. The sealing strip 8 is formed in a number of lengths separated by a small gap 12 to allow expansion of the individual strips 8, when subjected to high temperature. Each gap is bridged by a plunger 13 shaped to the inside contour of the sealing strip 8 and which formed parts of a spring member 14. Curved arms 15,16 extend from the plunger 13 and act to push the plunger upwardly into the interior of adjacent sealing strips -8 thereby bridging the gap 12 and closing it to the passage of fluid between the sealing strips.

It will be seen that any expansion of the sealing strips 8 due to high temperature is not impeded by the plunger 13 of the spring member 14, and any out-of-alignment of a surface 17 against which the noses 9 of the sealing strips abut may be accommodated by flexure of the arms 15,16 of the spring member.

The seal assembly shown in Figures 1 to 3 is shown in use in Figure 4 where a circular butterfly closure member 20 is mounted for rotation about an axis 21 in a fluid duct 22. Duct 22 is coupled to a larger duct 23 carving the main fluid flow and it can be seen that when the butterfly closure member 20 is in the closed position shown by the full line, there is no flow communication between the two ducts. The closure member 20 is shown in the open position the broken line 24. In the mouth of the duct 22 is secured a pair of seal assemblies 25,26 each being of semi-circular plan form and each comprising a housing member 1, several sealing strips 8 which have been slid into the housing member 1 through an open end of that member together with the appropriate number of spring members 1.

Any misalignments that may occur between the sealing strips 8 and the surfaces 27,27 of the butterfly closure member 20 against which the strips abut are compensated for by the actIon of the spring members 14.

In certain circumstances the interior of the sealing strips 8 may be connected to a source cf fluid pressure so that the force exerted by the spring members 14 holding the sealing strips s against the abutted sealing surface may be augmented.

It can also be seen that manufacturing tolerances of the various members of the seal assembly need not be extreme as the assembly is able to accommodate very wide tolerances; thus manufacturinq costs can be kept to a minimum.

The invention has particular utility in so-called vectoring arrangements employed in vertical-short take off and landing type aircraft where a gas stream produced by a gas turbine engine is tapped and diverted from the main exhaust gas flow duct by one or more butterfly members into secondary ducts supplying remote lift nozzles. In such use seal assemblies of the kind described above would be used at the junctions of the main exhaust gas flow duct and each of the secondary ducts, angular positions of the butterfly members determining the proportion of exhaust gas used for such purpose. With the butterfly members in the closed position all of the engine exhaust gas stream would then be available for forward flight.

Although the seal assembly has been described as being applied to the sealing of a rotatable butterfly type valve it will be understood that it is equally applicable to the sealing of valves which have a slidable closure member. One such arrangement is shown in Figures 5 and 6 in which the closure member comprises an annular sleeve 30 having flanged peripheral edges 31,32. The seal assembly is in two parts 33,35. The part 33 is secured to edge 31 by a nuts-and-bolts fixing 34 and the part 35 being secured to an extension of the edge 32 by a similar fixing. A bracket 36 is secured to the edge 32. Drag links 37 connect the bracket 36 to the nut 38 of a recirculating ball nut mechanism, the threaded spindle 39 of which is mounted in bearings 40 for rotation by means of an electric motor (not shown).

Upon rotation of the spindle 39 the nut 38 is driven along the spindle until the seal assemblies 33,35 engage sealing surfaces 41,42 around the mouth of a duct 43 which is coupled to a main fluid flow duct 44.

Claims (20)

1 A seal assembly comprising a substantially hollow housing member having an elongated opening through a wall of the housing, an elongated sealing member having a body portion for locating within the housing and a nose portion for projecting through the elongated opening, and resilient means whereby the nose portion of the sealing member is urged outwardly through the elongated opening.

2 A seal assembly as claimed in claim 1 wherein the housing member is of rectangular channel section.

3 A seal assembly as claimed in claim 2 wherein the housing member is provided with securing means whereby the housing member may be secured to a surface.

4 A seal assembly as claimed in claims 1, 2 or 3 wherein the sealing member is of top hat section.

5 A seal assembly as claimed in claims 2, 3 or 4 wherein the housing member and the sealing member are of metal construction.

6 A seal assembly as claimed in an preceding claim wherein the resilient means includes a plunger capable of engagement within a sealing member.

7 A seal assembly as claimed in claim 6 wherein leaf springs extend from the plunger.

8 A seal assembly as claimed in claim 7 wherein the plunger and leaf springs are of metal and form an integral construction.

9 A seal assembly comprising a substantially hollow housing member having an elongate opening through a wall of the housing, at least two elongated sealing members each having a body portion for location within the housing and a nose portion for projection through the elongated opening, and resilient means whereby the nose portions of the sealing members are urged outwardly through the elongated opening.

10 A seal assembly as claimed in claim 9 wherein the end of adjacent sealing members are engaged by a resilient means.

11 A seal assembly as claimed in claim 10 wherein the resilient means includes a plunger engaging within a recess formed by the ends of adjacent sealing members.

12 A seal assembly as claimed in claim 11 wherein the plunger is provided with leaf springs extending from and integral with the plunger.

13 A sealing arrangement for a valve wherein there is provided a seal assembly as claimed in any preceding claim, the sealing arrangement comprising a fixed seat and a closure member displaceable relative to the seat, the seal assembly acting between the seat and the displaceable closure member.

14 A sealing arrangement as claimed in claim 13 wherein the closure member is mounted for rotary displacement relative to the seat.

15 A sealing arrangement as claimed in claim 13 wherein the closure member is mounted for liner a displacement relative to the seat.

16 A sealing arrangement as claimed in claims 13, 14 or 15 wherein the valve is provided in the gasecus fluid distribution ducting of a gas turbine engine driven lift system.

17 A sealing arrangement as claimed in claim 16 wherein the lift system is provided in a vertical-short-take-off and landing aircraft.

18 A seal assembly substantially as described herein with reference to Figures 1 to 3 of the accompanying drawings.

- A sealing arrangement substantially as described herein with reference to Figure 4 of the accompanying drawings.

20 A sealing arrangement substantially as described herein with reference to Figures 5 and 6 of the accompanying drawings.