US2600855A - Governor-controlled compressor and the like - Google Patents

Description

June 17; 1952 5, DALE 2,600,855

GOVERNOR-CbNTROLLED COMPRESSOR AND THE LIKE Filed March 18, 1946 Patented June 17, 1952 UNITED STATES PATENT OFFICE GOVERNOR-CONTROLLED ('JOIVIIRESSOR AND "THE LIKE" Josephs. Dale, nockfordpllle Application March 18, 1946, Serial No."655, 087

e-fllaims. 1

This invention relates to a governor-controlled compressor :and similar structures.- The invention-will be found applicable tomachines driven by prime movers and in which the load upon the prime mover increases to. a maximum then decreases.

In the operation-or compressors and the like, it is the ordinary practice for the prime mover to operatesteadi'ly untilth pressure tank is at the desired pressure, at which time the compressor is cut offi" When the pressure again drops to a predetermined point, the-compressor cuts in again. Th constant cutting on and oil? of the compressor results in a: noisy and inefiicient operation. It-is highly desirable, in operating an'air compressor, to have the prime mover slow down as pressure increases and to go faster as the pressure decreases.

An object oithe present invention is "to provide control mechanism which will slow down the operationof the prime mover as the load thereon increases or as the pressur within the pressure tank 'increases,while, at the same time, allowing a-iaster speed of the prime mover when pressure is low. Aifurth'er object is; to provide meansv w-herebywhen the pressure within the pressure tank has reached its desired maximum and the compressor is in idling operation, the prime mover will nevertheless bemaintained at a relatively low speed. A furtherobjectisto providea governon the present invention; Fig. 2, a side view in elevation and'partlyin section of the governor and associated apparatus embodying my invention; Fig; 3, a--broken-side -view in elevation of combination apparatus embodying my invention; and Fig.4, an enlarged detailed sectional view of the pressure line connection shown in Fig. 3.

In the illustration given, A designates a prime mover; B, a'compressor driven thereby; C, a pressure tank supplied withpressure fluid by compressor B; I D, a governor driven by; the prime mover; andE; link mechanism connecting the 2; overnor-and primermover-to effect apontrol or the prime mover.

The prime mover A may be of any suitable, type or construction. In; the particular illustration, given, it consists of a motor equippedwith-a throttle valve H] which controls the intake of fuel into the manifold] 1. Since the type or character of the primemoverdoes not enter directlythe present invention, a-detailed descriptionds. here unnecessary. Themotor A drives through a flexible coupli I2.' he compressoriB- The compressor Bmay :be of any suitable ty e or construction. Since the specific formw em,-,

ployeddoes-not enter-into th inventionherein The pipes 13 and I4 are connected by a T-fitting: l5. To. the upper end of T-fitting I5 is secured a flexible hose [6. The air valve His a well known structure, employed with practically all air compressors commonly known as an unloads: ingvalves.

The coupling connecting hose I6 to T-fitting;

15 maybe provided with a ball-check valveilfia, as shown; inFig. 4.

The governor D, may be of any suitabletypeon construction. While in the illustration ,giveI.1:.; I

have shown arspecific form of .hvdr ulicgovemorr it will bemnderstood that any type of governor which employs a-speed setting control shaft and;

an actuating-arm:forpontrolling the prime movermaybe employed.

Th general type. of hydraulic governor-illuse trated in the :drawingis well known in the art. The governor is equipped with a'driven shaft I8,

which is connected through shaft .19 to a driven member of 'the motor inprime 'moverA. The governor controls the prime mover A by means of an actuating arm 20 which is in the form of "a plunger, beingdriven inwardly when the feed of fuel, pressure fluid or other motive-fluid to the prim mover-is to bereduced and being pressed outwardly-when the same is to be increased; In" the specificillustrationgiven, the plungerliiis a' partof a fluid driven 'servomotor and-it is connected through the link 2| to a bell crank 22,-th'ebell crank being pivoted at 23upon a-bracket arm I 24 secured to the-bottom of the governor A. The

outerarm of bellcrank 22 is secured, through rod: '25'to asecondbel-l crank 26, pivoted upon the prime mover at 21, as shown best in Fig. 3. The bell crank 26 is connected through rod 28 to a third bell crank 29, pivoted at 30 upon the prime mover. Another connecting rod 3| joins crank 29 to a lever arm 32 fixed to the throttle valve or fuel valve-control shaft In. With the structure described, operation of th servomotor plunger 23 serves to control the throttle valve Ill.

The linkage E, in addition to the connections already described between the plunger 20 and the throttle valve ID, provides means for changing the speed setting control shaft 33 of the governor. The speed setting control shaft 33 is present in practically all governors and provides a means for adjusting the spring or other means of control through which a pre-determined speed setting is obtained. Since the specific form of the speed setting control mechanism is not a part of this invention, a detailed description is believed unnecessary. The specific form of speed setting control in the governor A shown herein is set out in great detail in my copending application for Governor Mechanism, Serial No. 655,086, filed March 18, 1946, now U. S. Patent No. 2,571,842.

In the illustration given, the rotatable speed setting control shaft 33 is fixed to a collar 34 integrally formed with the control arm 35. The control arm 35 is pivotally secured to a rod 36 which is equipped at its inner end with a piston 31. The piston 31 is mounted within a cylinder 38. The opposite end of the cylinder 38 is connected by means of the threaded rod 39 to the upper end of the bell crank 26. A spring 40 is interposed between the piston 31 and the outer end of the cylinder 38. The flexible conduit l communicates with cylinder 38 on the inner side of piston 31, as shown more clearly in Fig. 2.

Operation Assuming that it is desired to operate the prime mover, by way of example at 400 R. P. M. minimum and 1200 R. P. M. maximum, the linkage E is so arranged as to give 400 R. P. M. when the tank pressure is 150 p. s. i. (assumed maximum), and 1200 R. P. M. when the tank pressure is 100 p. s. i. (assumed minimum operating pressure).

Assuming that the pressure is zero p. s. i. in

the pressure tank C, in starting, the governor will operate the prime mover at 1200 R. P. M. (maximum speed setting) until we reach 100 p. s. i. pressure in the tank. At this point, the governor speed adjusting arm 35 is against the high speed stop 42 and spring 40 is compressed. Above 100 p. s. i., the torque required to operate the compressor will load the prime mover and the plunger will move out the swinging bell crank 22, rod 25, crank 26, rod 28, crank 29, rod 3|, and valve lever 32 so as to increase the flow of fuel to the prime mover. At the same time, the outward movement of crank 26 draws rod 36 outwardly and swings arm and the speed setting control shaft 33 in a counter-clockwise direction. This movement of the shaft 33 lowers the speed setting of the governor. This operation will continue until the maximum pressure of 150 p. s. i. in the tank has been reached and the prime mover is running at 400 R. P. M.

When the maximum pressure has been reached, the air valve l1, which is set to operate at 150 p. s. i., will function, as it does in common practice with air compressors, to cause the compressor to cease pumping. The release of pressure in line 13 would thereupon cause the piston 31 to return to its quiescent position against stop 44 but for the action of valve l Ba in holding the air trapped within cylinder 38. Valve Ilia holds the air for a substantial period before it can leak from cylinder 38 and the linkage E is thus able only slowly to extend its length under the urging of spring 40. This results in the prime mover increasing speed very gradually rather than abruptly as in conventional arrangements.

I provide a governor pull back spring 4! as indicated in Fig. 3. In a specific example, the spring had a force of about 24 pounds. The size of piston 31 was such that with the air pressure used, I could obtain about a 12-pound force. The spring 40 in the cylinder 38 operating the piston 31 exerted about 6 pounds force (more force than was necessary to operate the speed adjusting arm 35) I provide a high speed stop 42 which engages the speed adjusting arm 35 in the starting up operation. When the prime mover is initially started, spring 41 overrides spring 40 and compresses it, forcing arm 35 clockwise against stop 42.

As the load increases, the servo 20 comes out and. spring 40 lengthens until at p. s. i., the piston 31 is held against stop 44 formed by a shoulder in the bore of cylinder 38. Above 100 p. s. i., as the servo 20 comes out due to load, the link 35 pulls the arm 35 away from the high speed stop and slows the prime mover down until at maximum p. s. i.) it is running at minimum speed and the arm 35 is against the low speed stop 43. At this time valve [1 functions and the load is removed from the prime mover. Piston 31 is forced in by the compressed air admitted through channel Hi. This holds arm 35 against the low speed stop 43 and the pull back spring 4| forces the servo in. holding the prime mover at idling speed.

When the pressure again drops below 150 p. s. i. (determined by air valve differential), the compressor becomes operative again for supplying pressure fluid to the tank C. In the meantime, linkage E lengthens and the operation of the prime mover again moves the compressor under load.

The new structure eliminates the continual cutting in and out of the air compressor as is now common. Within the range of the compressor, there is a considerable speed change which would handle the various different amounts of air being used.

Upon the operation of the valve device II which lifts the load of the compressor from the prime mover, the prime mover at once starts to ward its maximum R. P. M. of 1200 and would maintain this high speed were it not for the effective control provided through the cylinder 33 which immediately shortens the linkage E and changes the speed setting shaft 33 so that the prime mover will, instead of racing at its maximum speed, operate at 400 R. P. M. (its minimum speed) While in the foregoing description, I have set forth a specific embodiment in considerable detail, it will be understood that such details may be modified widely by those skilled in the art without departing from the spirit of my invention.

I claim:

1. In combination, a prime mover provided with a speed-varying lever, an air compressor driven thereby, a pressure tank, conduit means including an unloading valve coupling the. compressor to the tank, a hydraulic governor coupled to the prime mover and provided with a speed-setting member and a control shaft for regulating the speed of the prime mover, linkage coupling the control shaft to the speed-varying lever of the prime mover, connecting linkage coupling said first-mentioned linkage to the speedsetting member operative to change the speed setting of the governor when the first-mentioned linkage is moved, said connecting linkage being provided with an expansible coupling whereby its over-all length can be varied, and a second conduit means connected to the output of said compressor and operative to vary the length of said connecting linkage responsively to the pressure generated by said compressor.

2. Apparatus according to claim 1 wherein said expansible coupling comprises a cylinder rigidly afiixed to one side of the connecting linkage and a spring-biased piston reciprocable therein, said piston being provided with a piston rod connected to the other side of said connecting linkage.

3. Apparatus according to claim 1 wherein said second conduit means is provided with a check valve tending to hold for a period of time the pressure in said conduit means at the maximum value attained by said compressor 4. Apparatus according to claim 1 wherein said expansible coupling comprises a, cylinder rigidly affixed to one side of the connecting linkage and a spring-biased piston reciprocable therein, said piston being provided with a piston rod connected to the other side of said connecting linkage, and wherein said second conduit means is provided with a check valve tending to hold for a period of time the pressure in said second conduit means at the maximum value attained by said compressor, said pressure being operative to change the effective length of the connecting linkage in a direction tending to slow down the prime mover.

JOSEPH S. DALE,

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

UNITED STATES PATENTS Number Name Date 1,550,875 Carpenter Aug. 25, 1925 1,550,876 Carpenter Aug. 25, 1925 2,137,219 Aikman Nov. 22, 1938 2,171,285 Baker Aug. 29, 1939 2,178,660 Carpenter Nov. 7, 1939 2,212,631 Baker Aug. 27, 1940

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