Abstract: A downhole tool includes a housing; a first piston arranged within the housing such that it can move axially under the action of fluid flowing through the tool; and an indexer configured to control axial movement of the first piston between a first, second and third axial position. The indexer is configured such that the first piston can be selectively moved into the third position in accordance with a variation of a flow of fluid through the tool. A second piston is movable between a closed position in which fluid flowing through the tool is restricted from communicating with an activation chamber and an open position in which fluid flowing through the tool is permitted to communicate with the activation chamber; wherein the second piston is configured to move between the closed position and the open position in response to the first piston moving to the third axial position.

Abstract: The invention relates to post-transfusional non-A non-B hepatitis viral polypeptide, DNA sequences encoding such viral polypeptide, expression vectors containing such DNA sequences, and hosts transformed by such expression vectors. The invention also relates to the use of such polypeptides in diagnostic assays and vaccine formulations.

Abstract: In a gas turbine engine having gaseous oxidant delivered to a turbine from a source such as a pressurized bottle via a conduit or duct, a compact annular combustor is provided which offers enhanced performance through incorporation of means for uniformly distributing portions of the oxidant utilized as a diluent, and for convective cooling of engine components.

Abstract: An analgesic anaesthetic composition comprising up to 50% v.backslash.v nitrous oxide, the balance being oxygen and another respirable gas; characterized by the addition of an analgesically effective amount of an ether-based analgesic anaesthetic disposed in a single container above its pseudo-critical temperature at a pressure of up to 2000 psi, thereby to form and maintain a homogenous analgesic composition.

Abstract: Difficulties in starting a turbine engine, particularly ones having a small volume combustor (83) with a low dome height, may be avoided by a method including the steps of a) forming the turbine engine compressor (48) of a low density, high temperature resistant ceramic material, b) directing pyrotechnic gases at a temperature of at least about 3,000.degree. F. against the blades (48) of the compressor, c) continuing the step of directing until the turbine rotor (44) is rotating at at least about 60 percent of rated speed and d) combusting fuel in the combustor (83) of the turbine engine to maintain the rotor (44) rotating at at least about 60 percent of rated speed.

Abstract: Surge protection is achieved in a turbine engine intended to provide varying quantities of bleed air and having two compressor stages (48, 36) by providing the inlet (56) of the first stage (48) with variable inlet guide vanes (58, 60). The first stage compressor (48) is a high specific speed, single stage centrifugal compressor whose stable operating characteristics are highly sensitive to inlet guide vane geometry, thereby allowing variations in such geometry to be employed to prevent compressor surge.

Abstract: Difficulties in starting a turbine engine, particularly ones having a small volume combustor (83) with a low dome height, may be avoided by a method including the steps of a) forming the turbine engine compressor (48) of a low density, high temperature resistant ceramic material, b) directing pyrotechnic gases at a temperature of at least about 3,000.degree. F. against the blades (48) of the compressor, c) continuing the step of directing until the turbine rotor (44) is rotating at at least about 60 percent of rated speed and d) combusting fuel in the combustor (83) of the turbine engine to maintain the rotor (44) rotating at at least about 60 percent of rated speed.

Abstract: Inefficiencies in the operation of auxiliary power units producing electric and hydraulic power along with bleed air resulting from independence in the demand for power may be minimized in a system including at least one bleed air consuming system (84, 86), an electrical generator (92), a hydraulic pump (90), and a turbine wheel (10, 20) for driving the generator (92) and the pump (90). Also included is a combustor (32) for receiving fuel and compressed air and producing gases of combustion to drive the turbine wheel (10, 20). A rotary compressor (10, 14) is coupled to the turbine wheel to be driven thereby. The compressor (10, 14) is a radial discharge compressor with an impeller having blades (14) extending from an inlet end (40) to a discharge end (42) and a shroud (18) to the blades (14). Two axially spaced annular ports (44, 46; 44, 50) are adjacent the discharge end (42).

Abstract: The diameter of a gas turbine engine may be reduced through the use of a construction including a monorotor (44) journaled for rotation and mounting compressor blades (48) at one end (46) and turbine blades (56) at an opposite end (54). An axial diffuser (96) receives the discharge from the compressor blades (84) and is contained in a plenum (98). A reverse flow, annular combustor (83) is disposed about the rotor (44) and has a dome (100) whose height is a minor fraction of the axial length of the combustor (83) and which discharges to an annular turbine nozzle (77) having axial turbine nozzle blades (76).

Abstract: In order to establish a larger dome height to thereby increase combustion volume within the same turbine engine envelope, the inner wall region of an annular combustor is formed to define a thrust nozzle which in turn provides an enhanced combustion zone. The turbine engine will include a rotary compressor and a turbine wheel coupled to the rotary compressor for driven movement thereof along with an annular nozzle proximate the turbine wheel for directing gases of combustion thereat. The annular combustor will be disposed about the turbine wheel and defined by a radially extending wall region connecting the inner wall region to an outer wall region such that the annular combustor has a combustion zone upstream of the annular nozzle and a dilution air zone intermediate the annular nozzle and the combustion zone.

Abstract: In order to establish a larger dome height to thereby increase combustion volume within the same turbine engine envelope, the inner wall region of an annular combustor is formed to define a thrust nozzle which in turn provides an enhanced combustion zone. The turbine engine will include a rotary compressor and a turbine wheel coupled to the rotary compressor for driven movement thereof along with an annular nozzle proximate the turbine wheel for directing gases of combustion thereat. The annular combustor will be disposed about the turbine wheel and defined by a radially extending wall region connecting the inner wall region to an outer wall region such that the annular combustor has a combustion zone upstream of the annular nozzle and a dilution air zone intermediate the annular nozzle and the combustion zone.

Abstract: A method of starting a gas turbine engine eliminating the need for oversizing a starter motor or the like to attain a proper transition through the "pinch point" includes the steps of applying a torque from an external source to the gas turbine engine (10) to accelerate the same toward a self sustaining speed, igniting fuel in the engine (10) at a pre-determined speed less than the self-sustaining speed, and at or about the time of fuel ignition, momentarily increasing the torque applied to accelerate the engine (10). The acceleration torque and momentary increase can be achieved by applying torque from a gas turbine containing auxiliary power unit (20) to an engine (10) either mechanically or pneumatically and then overspeeding and/or increasing the turbine inlet temperature of the gas turbine within the APU (20) to achieve a momentary burst of torque.

Abstract: Unstable operation of a gas turbine engine subject to variable shaft loading and bleed air loading may be avoided in a gas turbine (12, 22, 40) having first and second stage compressors (12, 22) on a common shaft (10) with a turbine wheel (40) and by providing the inlet (14) to the first stage compressor (12) with variable inlet guide vanes (16). Bleed air flow is controlled by a bleed air valve (60) connected to the interface (24) of the first stage compressor outlet (18) and the second stage compressor inlet (20). A controller (66) is operative to control the position of the inlet guide vane (16) in response to bleed air flow sensed by a sensor (58).

Abstract: In order to provide an expansive central recirculating gas zone (40) in a combustor (10), and in a manner wherein the combustion chamber (20) is of compact volume, a stored energy combustor (10) comprises a vessel (12) having narrow, spaced-apart inlet and outlet ends (14, 16) interconnected by a wall (18) defining a relatively wise combustion chamber (20). The combustion chamber (20) is generally annular and a wall (18) defining the combustion chamber (20) includes an upstream wall region (18a) and a downstream wall region (18c) interconnected by a generally annular side wall region (18b). The inlet end (14) and outlet end (16) are generally tubular extensions of the vessel (12) leading to and from the combustion chamber (20) and oxidant is swirled in the tubular extension (14) leading to the combustion chamber (20) and directed in a swirling annulus into the combustion chamber (20) outwardly of a fuel injector (28).

Abstract: The high cost of the fuel injection system in a gas turbine engine can be reduced by utilizing a low cost jet or nozzle (70) to spray fuel into the inlet (24) of a compressor (18). The resulting air-fuel mixture flows as a semi-discrete sector to a combustor (58) to be swirled therein and combusted to drive a turbine wheel (50).

Abstract: Time lost in recharging compressed gas storage bottles on board aircraft is minimized with a fast recharge compressor (20) for rapidly providing compressed gas (30) having a housing (24) with a gas inlet (26), a shaft (46) within the housing (24) on which is mounted a turbine (34) and a multi-stage compressor (36). The turbine (34) is designed to run the shaft (46) and thereby the multi-stage compressor (36). Entering gas is divided into two streams and one stream (28) is directed through the turbine (34) while the other stream (30) is directed through the compressor stages (38,40,44). Heat is exchanged between the two streams by heat exchangers (52,54,56,57,60) after the expansion stream (28) has passed through the turbine (34) so as to cool the compression stream (30).

Abstract: A power augmented gas turbine starter system which has a starter including a casing rotatably mounting a turbine wheel therewithin. A low pressure air supply communicates with the casing. A combustor is associated with the low pressure air supply for receiving air therefrom and supplying a flow of hot gas to the starter for augmenting the power of the starter. The air supply may be a bleed air conduit from an auxiliary power unit or from a main propulsion engine, and the combustor may be removably mounted directly in-line within the air supply conduit. The invention contemplates the use of a single auxiliary power unit and a single combustor for supplying a flow of hot gas to two or more gas turbine starters associated with their respective main propulsion engines. A cross-bleed circuit may be provided so that cross-bleed from one main engine can be used to start another main engine by providing bleed air for the other engine's gas turbine starter.

Abstract: Surge protection is achieved in a turbine engine intended to provide varying quantities of bleed air and having two compressor stages 48, 36 by providing the inlet 56 of the first stage 48 with variable inlet guide vanes 58, 60. The first stage compressor 48 is a high specific speed, single stage centrifugal compressor whose stable operating characteristics are highly sensitive to inlet guide vane geometry, thereby allowing variations in such geometry to be employed to prevent compressor surge.

Abstract: A narrow efficient operating island for a centrifugal compressor may be increased in a construction including a compressor section 18 mounting blades 22 surrounded by an annular shroud 38 by placing bleed passages 88 in the shroud 38 and angling them in the direction of flow, both axially (FIG. 1) and radially (FIG. 3).

Abstract: The combustion dynamics and efficiency of gas turbine having an annular combustor 26 provided with fuel injection nozzles 50 that inject fuel generally tangentially is improved by providing the walls 32, 34, 39 of the combustion 26 with cooling air film injectors 70, 86; 72, 88; 74, 90 at substantially equally angularly spaced locations about each such wall and which are oriented to generally tangentially inject a film-like air stream on the associated wall 32, 34, 39.