US2628672A - Hydraulically operated speed governor for jet engines with electrically operated safety device - Google Patents

Description

Feb. 17, 1953 G. SILVESTER HYDRAULICALLY OPERATED SPEED GOVERNOR FOR JET ENG WITH ELECTRICALLY OPERATED SAFETY DEVICE Filed June 30, 1950 INES INVENTOR. fiUSW/V 61 57A VfSTEE Patented Feb. 17, 1953 f HYDRAULICALLY OPERATED SPEED GOVER- NOR FOR JET ENGINES V/ITH ELECTRI- CALLY OPERATED SAFETY DEVICE Austin G. Silvester, Schenectady, N. Y., assignor to the United States of America as represented by the Secretary of the Air Force Application June 39, 1950, Seriai No. 171,422

2 K'Jlaims.

This invention is an improvement of the device shown in my prior Patent No. 2,411,065 of November 12, 1946, and relates to speed governing mechanism for gas turbines and jet engines.

The governing mechanism shown in the above patent is generally employed for the purpose specified and generally operates satisfactorily so lon as there is no dirt in the fuel system, yet has been known to become inoperative for the purpose intended when even a small chip of dirt in the fuel lodged in the pilot valve of the relay system in the governor, thereby causing the pilot valve to stick and in consequence rendering the governor inoperative to control the speed. If this should happen in a position where closed bypass valve was indicated, the engine would shut down, which if it happened during take-off would have fatal results.

The present invention consists of an addition to the conventional governor and is designed to obviate the above fault in the conventional governor and provide a mechanism which will in effect eliminate the governor from the fuel system in the event it should fail to function normally as for instance if it should operate to shut the engine down.

An object of the invention is to provide a simply constructed and inexpensive mechanism which will obviate the faults above enumerated.

I attain this and other objects in the device hereinafter described, reference being had to the drawing wherein the single figure of the drawing is a schematic perspective view of the conventional jet governor with the safety attachment which is the subject of thi invention, applied thereto.

' Like reference characters refer to like parts throughout the drawing.

For a proper understanding of the operation of the mechanism which is the subject of this invention, that portion of the specification of Patent No. 2,411,065, supra, from column 2, lines 35 through 55, through column 3, lines 1 through 31, should preferably be understood.

Referring now to the drawing, a fuel pump it takes fuel from a tank I2 through pipe 14 and discharges it for the greater part through pipes l6 and I8 into the space 29 between the cartridge 22 and casing 24 of the filter 26. A pipe 28 conveys fuel from the inside of the cartridge 22 to the burner 30 of a jet engine 32.

A flyweight governor 34 is rotated by the engine 32 through any suitable power transmitting means such as the belt 36. The shaft 38 of the governor 34 is bored to slidably receive the axially sliding spindle 40. The flyweight governor 34 is adapted, upon outward movement of its weights, to slide the spindle axially toward the left in the drawing, and upon inward movement of the weights to slide the spindle axially toward the right.

Secured to one end of a shaft 42 is the hub of a lever arm 44. The arm 44 extends downwardly and is provided near the lower end with a tapped hub 46. An adjusting screw 48 in the tapped hub 45 extends through the lever from left to right. An electric switch 4| is insulatedly supported on the arm 44, and when its contacts 43 and 45 are closed as they are during normal operation, fills the space between the end of the adjusting screw 48 and the end of the sliding spindle 4t. A spring 47 normally holds the end of the adjusting screw 48 against the governor operated switch assembly 4| and the switch as sembly 45 against the end of the sliding spindle 4d. The switch 4| is biased to separate its contacts t3 and 45 when they are not held together by the spring 41 as shown.

Secured to the other end of the shaft 42 is a horizontally disposed lever arm which is hinged at its swingable end to a vertically disposed link 52,

The lower end of the vertically disposed link 52 is hinged to one end of a long horizontal lever 54, the other end of the long lever 54 being hinged to the upper end of the stem 56 of the pilot valve 53, The long lever 54 is fulcrumedon a shaft 60 which is eccentrically supported on the endof a shaft 6| for reasons hereinafter described.

A valve operating cylinder 62 has a piston 64, the spaces above and below the piston being sup plied with pressurized fuel from the inside of the filter cartridge 22 through pipes 66, 68 and m, the stem 56 of the pilot valve 58 being so constructed that when the stem 56 is in the medial position shown, no pressurized fuel will flow into the cylinder 52. If, however, the stem 55 is moved to the upper position; fuel will flow through the pipes 65 and 65 into the space above the piston and the piston will move downward, while if the stem 56 is moved to the lower position, fuel will flow through the pipes 66 and 10 into the space below the piston and the piston will move up ward.

The piston rod 12 is joined by a link 14 to the swingable end of a lever arm 16 which is fast on a shaft 6|, supra, the rotatable member of a bypass valve 82 being fast on the other end of the shaft, whereby underspeeding of the engine 32 and its governor 34 will retract the governor spindle 40 toward the right, which will allow the extension spring 41 to rock the shaft 42 anticlockwise, raise the link 52, rock the lever 54 anticlockwise about its fulcrum 60, move the pilot valve stem 56 to its lower position, allowing pressurized fuel into the. cylinder 62 to raise the piston 64, thereby rocking the shaft 61 clockwise and closing the governor valve 82. Moving the valve 82. to closed position by rotation of the shaft 6| causes the eccentric shaft 60 to return the stem 56 of the pilot valve 58 to the medial position.

As long as the main governor valve 82 was partly open, a portion of the pressurized fuel flowed from the discharge side of the pump through pipe l6 and governor valve 82, through pipe 84, through a normally open solenoid valve 88 and through pipe 86 to the. suction side of the pump I whereby the more nearly the governor valve 82 is closed the more fuel must flowthrough pipe 18, filter 2B and pipe 28, and therefore the greater will be'the pressure build up and amount of fuel flow atthe point where the pipe 28 feeds fuel into the burner 30.

' Thus far the'device has been described as-being operated hydraulically. It has happened, however, that coincidentally with underspeeding of theengine 32 a chip or other foreign matter would get into the pilot valve 58 and stick its stem- 56 whereby the hydraulic mechanism failed tofunction, governor valve '62 remained open the engine being thereby shut down. The result of this happening. ontakeoif is well known and it is to' forestall such an occurrencethat the electrical components shownhave been added. These com ponents comprise a battery 90 or equivalent sourceof electric power, the normally closed relay 92-, the normallyopen solenoid valve 88, the governor operated electric switch 4l' hereinbefore described and a master switch 94.

When the device is not in operation and the master switch 94 is open as shown, there is no currentin the: electric system and the spring 96 of the relay 92 will hold the relay closed. As soon as the master switch is closed current will flow from the battery terminal through the relay coil 98 and; the switch 4| and the relay will open. If thereafter the combination. of an underspeeding engine 32 and a stuck pilot valve 58- occur' simultaneously, the governor operated switch. 4! will open which: will break the circuit through the relay coil.!!& and the relay spring 96 willclose the relay 92 whereby a circuit is established. through the coil Hit of the solenoid valve 88, whereby-the plunger H32 of the solenoid valve will bemovedendwise and the solenoid valve will be closed whereby less fuel will be recirculated through pipe [6, valve 32, pipe 84, valve 88' and pipe 86 and more fuel will be directed to the burner 30 throughpipes I8 and 28 and the engine speed willtherebyagain be brought up to normal.

According to the foregoing. description, when the. speed of the engine 32 rises above a prede terminedv value, the sliding. spindle 413 is moved leftward whereby the: governor valve 82' is opened hydraulically whereby a suficient portion of the fuel being pumped. is returned to'the pump inlet to thereby lower the volumeof fuel going to the engine, whereby the engine speed is reduced.

Also when the speed of the engine 32 falls below a. predetermined value, the sliding spindle 40 ismoved rightward whereby the governor valve 82 is closed hydraulically, whereby all of the fuel 4 being pumped is directed to the engine whereby its speed is raised to normal.

It is only in the case of engine underspeeding where the sliding spindle moves rightward, that, due to some foreign matter getting into the mechanism, the spring. 41 cannot swing the lever e4 to close the valve 82 hydraulically as described, that the normally open solenoid valve 88 is closed to perform the function of the inoperative valve 32.

Having thus described an embodiment of my invention, I claim:

1. In a control device for a combustion engine, a governor adapted to be connected to an engine to be driven thereby at a rate proportion-a1 to the engine speed, a pump for supplying fuel under pressure to theengine, a fuel supply means connected to the pump, fuel delivery means connected to the pump and adapted to be connected to the engine, a first adjustable normally open bypass means interposed between the fuel supply means and the fuel delivery means and operatively as sociated therewith, adjusting means operatively interconnecting the governor and the adjustable bypass means, a second adjustable normally open bypass means interposed between the fuel delivery means. and the fuel supply means and means operatively interconnecting the adjusting means and. the second adjustable bypass means, said means operatively interconnecting the adjusting means being normally held inoperative by said adjusting means but operable to open upon failure. of said adjusting means.

2. In a control device for a'combustion engine, a governor adapted to be connected to an engine to be driven thereby at a rate proportional to the enginev speed, a pump for supplying fuel under pressure to the engine, a fuel supply means connected to. the. pump, fuel delivery means connected to the pump and adapted to be connected to the engine, a first normally open bypass means interposed between the fuel supply means and the fuel delivery means and operatively associated therewith, control means operatively interconnecting the governor and the first bypass means including a spindle slidingly operable by the governor, adjustable means axially aligned with the spindle, spring biased electrical contact means, interposed between the spindle and the adjustable means and normally held in closed position therebetween but operable to open upon failure of said adjustable. means, a second' normally open bypass means interposed between the fuel delivery means and the fuel supply means, and means opeiatively interconnecting the. electrical contact means and the second normally open. bypass means whereby on. failure of the first bypass means to function, the second bypass means will close to insure proper fuel delivery.

AUSTIN G. SILVESTER.

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

UNITED STATES PATENTS Number Name Date 2,316,445 Marshall Apr. 13, 1943 2,411,065 Silvester Nov. 12, 1946 2,469,271 Logan May 3, 1949

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