US2514248A - Device for automatically adjusting a variable jet nozzle for a jet propulsion unit with variations in the temperature prevailing in the jet pipe - Google Patents

Description

July 4, 1950 A. A. LOMBARD ET AL 2,514,243

DEVICE FOR AUTOMATICALLY ADJUSTING A VARIABLE JET NOZZLE FOR A JET PROPULSION UNIT WITH VARIATIONS IN THE TEMPERATURE PREVAILING IN THE JET PIPE Filed April 3, 1947 2 Sheets-Sheet 1 INVENTORS A. A. LOMBARD M.V. GOU KLAY 4' 6. SKIPWIT July 4, 1950 A. A. LOMBARD ET AL 2,514,243

DEVICE FOR AUTOMATICALLY ADJUSTING A VARIABLE JET NOZZLE FOR A JET PROPULSION UNIT WITH VARIATIONS IN THE TEMPERATURE PREVAILING IN THE JET PIPE Filed April 3, 1947 2 Sheets-Sheet 2 al a/5? Zomlard (M V gouff Patented July 4, 1950 DEVICE FOR AUTOMATICALLY ADJUSTING A VARIABLE JET NOZZLE FOR A JET PRO- PULSION UNIT WITH VARIATIONS IN THE TEMPERATURE PIPE PREVAILING IN THE JET Adrian Albert Lombard, Clitheroe, England, and Gordon Kenneth Luker Gourlay, deceased, late of Skipton, Yorkshire, England, by'Margaret Virginia Grimwood, .Cranleigh, and Grey Skipwith, Mortimer, England, administrators, assignors to Rolls-Royce Limited, Derby, England, a company of Great Britain Application April 3, 1947, Serial No. 139,184 In Great Britain March 9, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires March 9, 1965 3 Claims. (Cl. 60-455) This invention relates to variable jet nozzles for jet propulsion units and has for its object to provide an improved construction of automatic control means whereby the area of the nozzle may be controlled in accordance with the temperature of the gas in the jet-pipe.

According to this invention the parts which are movable to adjust the area of the nozzle are operated by a hydraulic ram which is itself controlled by a. temperature-sensitive device in the Jet-pipe.

Preferably the supply of pressure fluid to the hydraulic ram is controlled by a valve and there is provided a follow-up device actuated by the ram to cut oil the supply of said pressure fluid.

Specific embodiments of the present invention will now be described by way of example with reference to the accompanying drawing whereof,

Figure 1 is a diagrammatic view of an automatic control means for a variable jet nozzle in accordance with the present invention.

Figure la is a fragmentary longitudinal section of the tail end oi the jet pipe showing the details of the nozzle and the temperature responsive device, and

Figure 2 is a diagrammatic view of a modified construction of such control means.

Referring to Figure l, the jet-pipe is generally indicated by the reference numeral 5, the rear end of said pipe being provided with a pair of sector members i which are adjustable about a common pivot point 1 so as to vary the discharge area of the nozzle. The sector members I are connected by a linkage 8 with a hydraulic ram generally indicated at 9 the arrangement being that when pressure fluid is admitted to one end of the ram the sector members will be adjusted in one sense and when pressure fluid is admitted to the other end of the ram the sector members will be adjusted in the opposite sense. Such a general arrangement of power control has been described in the specification to patent agflication Serial No. 693,444, flled August 28, 1 8.

Pressure fluid is supplied to the hydraulic ram 9 by a pump It the suction side of which is connected with a reservoir II to which the fluid exhausted from the system is returned by a pipe II. The supply of fluid under pressure to, and the drain of fluid from, the ram 9 to effect its operation is controlled by a valve means indisure fluid to be delivered from the pump It to the ram 9 to adjust the sector members 6. The movement of the ram 9 is imparted thereby to the follow-up sleeve ll so that the latter cuts of! the supply of pressure fluid to the ram and at the same time closes the drain from the opposite end of the ram piston to the reservoir H by pipe l2. It will be appreciated that the end of the hydraulic ram 9 which is supplied with pressure fluid or drained of fluid is governed by the direction of movement of the piston I from its closed position such movement being determined by the temperature-sensitive device It in the jet pipe.

In use, if it is assumed that the piston I4 is moved by the temperature-sensitive device It to the right, pressure fluid passes from pump III by pipe ill to the left hand side of the hydraulic ram and simultaneously pipe 29 which connects with the right hand side of the ram is connected to drain by means of pipe 2|. The passage of fluid from pump Hi to pipe I9 and from pipe 29 to pipe 2| i stopped when the sleeve ll, which is moved to the right by the ram piston, closes the ports associated with said pipes. Similarly when the piston is moved to the left pressure fluid passes from pump ill to the right hand side of the hydraulic ram 9 by way of pipe 20 and the drain from the hydraulic ram is eflected by pipe l9 which i placed in communication with pipe ii. The movement of the rampiston will continue until the sleeve I! has been moved to close the ports associated with said pipes.

It will be observed from the flgure that a spring .22 is disposed between one end of the piston ll andthe adjacent end of the sleeve ll so as to maintain the piston H in engagement with the lever II.

In the modified construction shown in Figure 2 instead of operating the piston valve ll of the valve means 13 directly through a mechanical linkage by the temperature-sensitive device l6,

it is operated by fluid pressure which is derived from the same source (that is the pump M) as that which supplies the ram 9.

As in the construction described with reference to Figure 1 the piston valve I4 is engaged by a spring 22 so that it is urged in one direction and said piston valve is so mounted in the followup sleeve ll as to constitute a piston therein to which fluid under pressure may be supplied to move the valve towards the right or in which fluid is connected to drain so that the piston I4 is urged by spring 22 towards the left.

The temperature-sensitive device 16 is arranged to operate the piston 23 of a valve 24 which regulates the passage of fluid to, and from, the left hand end of the piston ll. The piston 23 is maintained in contact with the temperature-sensitive device by a. spring 25. With this arrangement if the piston 23 is moved towards the right, pressure fluid from the pump I is delivered to valve 24 by pipe 28 and passes by pipe 2'! to the piston I I. As a consequence pressure fluid is admitted to the left hand side of the ram 9 as described with reference to Figure 1 and such supply is terminated when the piston of hydraulic ram 9 has moved the sleeve I! towards the right to close the ports of valve means I. Similarly if the piston 23 is moved by spring 25 towards the left, the left hand side of piston I4 is connected with the reservoir H by means of pipes 21, 29 and piston II is therefore moved towards the left by spring 22. When this occurs pressure fluid will pass from the pump it to the right hand side of hydraulic ram 9 by pipe 20 such supply being stopped when the sleeve H has been moved to a predetermined extent towards the left.

It will be appreciated therefore that in the two constructions described the adjustment of the nozzle area to maintain constant temperature in the jet-pipe is determined by the temperature-sensitive device It disposed within the jet-pipe.

The particular advantage of the construction described with reference to Figure 2 is that the efiort required to be exerted by the temperaturesensitive device 16 can be made substantially less than that required to operate the piston I4 directly. The advantage of using a follow-up system of control as in the two constructions described is that hunting is avoided in the adjustment of the area of the nozzle.

We claim:

1. An aircraft jet propulsion system comprising in combination a jet pipe having an exit propelling nozzle, parts movable to adjust the area of said nozzle; a hydraulic ram to move said parts; a hydraulic pump to supply pressure liquid to said ram, a temperature sensitive device in said jet pipe, a first valve part actuated by said temperature sensitive device, a second valve part actuated by said ram, said valve parts being arranged in juxtaposition, so that supply of pressure liquid to the ram is initiated by movement of the first part and is cut oil by the resultant movement of the second part in follow-up action, and so that an increase in the temperature sensed by said temperature sensitive device results in movement of the parts to increase the area of said nozzle and vice-versa.

2. An aircraft jet propulsion system comprising in combination a jet pipe having an exit propelling nozzle, parts movable to adjust the area of said nozzle, a hydraulic ram to move said parts, a hydraulic pump to supply pressure liquid to said ram, a temperature sensitive device in said jet pipe, a part associated with said temperature sensitive device and moved in accordance with the sensed temperature, a first valve part, a mechanical connection between said part moved in accordance with sensed temperature and said first valve part, a second valve part actuated by said ram, said valve parts being arranged in juxtaposition so that supply of pressure liquid to the ram is initiated by movement of the first valve part and is cut off by the resultant movement ofthe second valve part in follow-up action, and so that an increase of sensed temperature results in movement of the parts to increase the nozzle area and vice-versa.

3. An aircraft jet propulsion system comprising in combination, a jet pipe having an exit propelling nozzle, parts movable to adjust the area of said nozzle, a hydraulic ram to move said parts, a hydraulic pump to supply pressure liquid to said ram, a temperature sensitive device in said jet pipe, a part associated with said temperature sensitive device and moved in accordance with the sensed temperature, a servo valve part, a mechanical connection between said servo valve part and said part moved in accordance with sensed temperature, a first control valve part actuated by hydraulic pressure controlled by said servo valve, so that said first control valve part follows the movement of the part moved in accordance with sensed temperature, a second control valve part actuated by said ram, said control valve parts being arranged in juxtaposition so that supply of pressure liquid to the ram is initiated by movement of the first control part and is cut off by the resultant movement of the second control valve part in followup action, and so that an increase of sensed temperature results in movement of the parts to increase the nozzle area and vice-versa.

ADRIAN ALBERT LOMBARD. By MARGARET VIRGINIA GRIMWOOD. GREY SKIPWITH, Administrators of the Estate of Gordon Kenneth Luker Gourlay, Deceased.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date.

2,095,991 Lysholm Oct. 19, 1937 2,338,021 Bennett Dec. 28, 1943 2,363,179 Harrington et a1. Nov. 21, 944 2,372,686 Sedille Apr. 3, 1945 2,392,622 Traupel Jan. 8, 1946 2,402,363 Bradbury June 18, 1946 2,411,895 Poole 1 Dec. 3, 1946

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