US1834593A - Compressor controlling mechanism - Google Patents

Description

y Dec. l, 1931. F. D. H'oLDswollR'rH 1,834,593l

COMPRESSOR CONTROLLING HECHANISM original Filed Nov. 24, 192s 2 sheets-sheet 1 [v2/venan' WedDHoZdswmWw ma-WMM.

Dec. l, 1931. F. n; HoLDswoRTH COMPRESSOR CONTROLLING MECHANISM original Filed Nov. 24, 192e 2 Sheets-Sheet 2 b21/WAM Amy.

Patented Dec. 1, 1931 *UNITED STATES PATENT oFFicE" 'I FRED D. HoLDsWoRTH, or cLAmiMoN'r, NEW HAMPSHIRE, ASSIGNOR 'ro SULLIVAN'` I ivIAcHINriaY coivirANY, A CORPORATION or MASSACHUSETTS `co:nrnizssoia coNTRoLLINe MECHANISM Application filed November 24, 1928, SerialfNo. 321,743. Renewed .Tune 4, 1931.

l This invention relates to a mechanism for controlling a prime mover as the load carried by the same varies. In another and more limited aspect, `my invention relates to controlling mechanisms for internal combustion engines employed in the driving of air conipressors and other pumping devices.

In vmodern internal lcombustion, engines, which as a general rule are provided With dem' vices for igiiitiiig the explosive mixture, the

timing'of the ignition is commonly auto'- niatically controlled in accordance with the speed' ofthe load carried by the engine. The e engine is therefore principally controlled by l regulation ofthe feed of the combustible mixtui'e tothe engine; and the'speed of the engine y and the machine driven thereby is maintained, as the load increases, by kfeeding a F greater volume of mixture. Accordingly, one im object of my invention is vto provide improved means for controlling the Supply of explosive mixture to an internal combustion engine as the demand made upon the Same varies. A further and more specific object of my invention is to provide improved means for controlling thesupply of explosive Lmixture to an internal combustion engine which is employed as the prime mover for an air compressor or other pumping device, increasing 39 or decreasing the supply in accordancewith the Idemands made by the compressor. A still further object of my invention is toprovide improved means for varying' the supply of w fuel to the engine which drives an air commechanism in which the illustrative embodi#v ment of the invention has been incorporated. Fig. 21s a sectional view through the intake and discharge valves of one cylinder of the compressor, the figure showing an unpressor in accordance with the loading andk `loading device which cooperates with the inlet valve.

Figf?) is a view in side elevation of the fuel supply control, a portion oftlieconitrolling mechanism being shown in section.v Fig. et is a section on line 4 4 of Fig. 3.

In Fig. 1 of the drawings a portable compressor outfit is illustrated,tlie same Aconi- `prising a motor 7 and a compressor 8 both' mounted on the frame 9 of awheeled truck.: The outfit isprovided with a fuel .taiik=10, and with a receiver 11 to whichthe air ,org other liuid being compressed is delivered by' way 0f the connection 12. rIhe compressor is provided with suitable inlet and discharge, valve mechanism. -In Fig. 2 is Shown apoi-. tion of one of the cylinders of thecompresson, with which cooperates a valve casing 13.with in which is disposed' a dischargevalve 1li and an inlet valve 15. A cylinder 16 iii the;v form of an inwardly projecting member 16*V is formed integral with a cap 17 secured to the end of the valve` casing 13. The cap17, is perforated at 18 to permit the air to enter. the valve casing. A piston 19 is i'eciprocab'le within the cylinder 16; and the cylinder 16v` and the piston 19 cooperate to act as a servo-motor to which fluid under pressure issupplied by way of a pipe connection 20. The piston 19 carries a stud or bolt 21 which supports a pronged member 22. The prongs. of the latter yare adapted to engage -tlieinlet valve as the piston 19 nears the inner .end of` its travel Within the cylinder 16. When the inlet valve 15 is so engaged it is lifted, and held olf its seat so as to unload the come* presser. w

The engine 7 is provided with an lintake supply connection 23withi-n whichis jdis posed a 'butterly'valve 24' (see Fig..3). A fluid pressure responsive device 25 controls:k the Same, being connected thereto byva linkage 26. The device`25 comprises acasiiig having two aliiied boies 27 andk Ap'pipel connection 29 delivers fluid at receiver pres-f.V sure to the bore 27.V Within the latter is reciprocablea piston V305 Within ,they bore 28 is disposed a second piston having a Sleeve-v lilre'portion v31 and alieadJportion 32;` the latter-portionbeing, if desired',secured"toY nection 39. The inner end'of'the '37.

communicates with the bore 28. "he sleeve member 31 acts as a val-veto control the lnassage 3,7, since a groove 40 is formed inthe periphery of the fsleeve member 31- van orifice 41 opens from the interior of the sleeve Imember 31 into thegroove 40. As the ,e sleeve member 31 reciprocates, the groove 40 "1s carried into and out or Communication with the passage 37.

`V'An end member 42 is secured-in any suitable manner ytothe portion of the device 25 inwhich bore`28 is formed.` The endV niember42 is provided withal-chamber 43 which is-alinedwitlrthe hollowinterior of the sleeve member 31. A 'threaded screw projects intotliis chamber,beingprovided with a loci;l

nut4`5. A spring 57 is disposed wimiin `the sleeve member One end of this spring abut-s-the-'end of the bore in the sleeve inem.- ber 31Hand the other end is provided with. anabutment member 58 against which bears e the endloffthescr'ew 44. A second chamber 46 is v'provided in the end 'member 42, into which "leads a passage 4'? which opens at its other'end'into the chamber 43. A continuation v38"'01'? the passage 33 yopens into the chamber 4G. A threaded ,plug 43 is'screwed into the vopen endof the chan ber 46,

valve '49 -has'a-ste'm 50 which is guided in the plugv48', a spring' 51 being adapted to pressthe 4valve 49 against a seatl 52 which formed inthe vmember42 at the :suction oit the passage 47 and the chamber 4G. pipe connection "53 ris tlrreadedly lconnectedtol a passage 53 which opens into the chamber' 43. `/.Xlsfshown in'IFg. 1, the pipe connec- I tion 53 leads to "a pilot lvalve 54 which is connected -by piping 55 to the receiver 11.

T he'connection 29 branches of'of this'saine plpe line 55. The pipe connection 39 leads by Away of piping 55 to the `co-nnections 20 whihleadinto the'motors for the unloading devices. The 'pilotvalve 54 of the type Whichsupplies actuating iiuid to the mechanism "controlled lthereby when the receive@` pressure `exceeds a apredctermined mai-inunn and lvents the mechanismV to .atmosphere when the receiver ,pressure falls a predetermined 'amount below .suol ,c maximum. y

The operation of the-:control device when the motor is being started is as follows. ItV willbe Vassumed that the receiverv 11 is empty.

' valve 54.

inwardly; and therefore the spring 57 has thrown the butterfly valve towards closed position. The 'engine is now started; and as the pressure in the receiver builds up, the pressureV in the bore 271 increases, .gradually- `throwing thelever 35,. and therefore gradually opening the butterfly valve 24, the spring 5T resisting such'movement of the piston 30. 1When the pressure in the receiver 11 has reached rthe -normal working pressure for which the compressor is designed, thebutterfly valve'24'will be in o pen position. The screw 44may be adjusted'to suitably'position the spring for this purpose.

Should the Vdemand for pressure' fluid .fall off, the pressure in Vthe yreceiver 11 may reach such a point as to actuate 'thepilot valve 5,4. lVhen 'this'v action takes 'place the lpilot valve delivers'uidthrough the connection 53 into the chamber 43,"this liuid being 4under 'the same pressure asthe iuid'inthe .bore 27. `lt will be noted that th'el'bore 28 however, is substantially largerthan the 4bore 27; and the sleeveelilre member 31 is 'therefore immediately moved outwardly Vso as lto shift the lever 35 and throttle down the .engine The pressure fluid in`chamber43 also acts against the valve 52, unseating the same so that the fluid may be delivered through passage 33 and connections 39,56, 20 to the motors of the unloading devices. The compressor is therefore unloaded.

lVhen'the pressure in the receiver 11 falls to the predetermined minimum pressure at which the pilot valve r54 is set to effect reloading, a 'vent in the pilot valve 54 willbe opened, andthe pressurev inthe chamber 43 will immediately fall. Thel closing of the check valve 49 has, however, trapped the pressure uidwithin the pipe connections` 39, 56, a-nd20 and within the cylinder 16. Thefluid pressure behind sleeve member 31, however, is vented, since the bore28 is connected to atmosphere by way ofv pilot valve 54. ySince full receiver pressure is 'actin-g withinthe bore 27,1theypiston-30 will move outwardly, pushing sleeve niember31 within the bore 28, thereby opening the butterfly valve 24 and once more speeding' up, the engine. Just before the' sleeve member 31 reaches the position illustrated in Figf3, the pressure fluid wliich'has meanwhile been holding the compressor unloaded isvented through passage 37', groove 40, the opening 41, the` chamber 43, the connection 53, and the vent in the pilot t will therefore benoted that the compressor is not loaded again until. ythe butterfly valve v24 controlling the supplyof fuel to.thegmotorhasfbeen nearly completely.

opened'thereby bringing' the engine and compressor up to speed. 'Y c c It will'be obvious from the above description'that, in accordance With my invention, the control vmechanism supplies fuel to the engine in accordance With the demands made upon the engine. Asthe pressure in the receiver l1 increases, more and more fuel is supplied to the engine, so that itis able to i carryrthe load o f compressing the fluid to receiver tank pressure. It should further be noted that as soon as the compressor is unloaded tlie supply of fuel to the motor is immediately-cut vdown so as to prevent racing of thc'motor. Then the pilot valve, due to a decrease in` receiver pressure,` functions to vent air. from the chamber. 43, the check valve 49 prevents immediate reloading of the compresser.` This provides an opportunity for the motor to come upto speed beforethe load is placed on the motor,'1t.being obviously` advantageous tohave the motor at its Work# ing or ordinary ruiming speedbefore the load is placed thereon. As, however, the engine throttle nearly reachesits full open position, the groove 40 begins to register With passage 37 and reloading of. the compressor takes place.

llVh'ile I have in this application specifically i described one form which the invention may assume in practice, it will be understoodthat this form of the same is shown for purposes of illustration and that the invention may be modiied and embodied i in various other forms Without departing from itsy spirit or the scope ofthe appended claims.

VVhatI claim as new and desireto secure by LettersPatent is: y

l. In a. controlling mechanism for a compressor system comprising a. compressor and a motor i'o-r driving the sam-e, in kcombination, unloading means for the compressor including actuating means adapted to be subjected to pressure to effect unloading ol the compressor, movable `means for controlling the relief of such Apressure tov cause loading of thecompressor, movable means for controlling the speed of said driving motor, and anl expansiblc chamber motor for moving siinuli taneouslysaid lirst and second mentioned movable control means to effect the loading of the compressor and an increase in the speed of said driving motor, the chamber of said cxpansible chamber motor being normally subjectedto the pressure of the discharge of the compressor.

2. ln al controlling mechanism .for a com. pressorisystcni comprising compressor and a motor `lor driving the same, in combination, unloadingmeans orthe compressor including actuating means adapted to befsupplied.

Wit-h medium under pressure to effect unload-v ing-of ,the compressor, means for controlling the Vexhaust of such medium for causing loading ofthe compressorincluding a movable an expansible chamber motor for moving' ksimultaneously said' first and second nientioned movable elements to eifect the loading oi: the compressor and an increase in the speed of said driving motor, the chamber of said expansible chamber noter being normally subjected to the pressure of the discharge of the compressor.

8. ln a controlling mechanism for a compressor system comprising a compressor and a motor for driving the saine, in combination, an unloading device for the compressor, means or supplying actuating medium to said unloading device, means for controlling the supply of such medium to sais unloading device and the venting of the saine Atrom said unloading means including a clieclr valve adapted to maintain the compresso-r unloaded,movable means for controlling the speed or said driving motor, and a servo motor for simultaneously,causing venting ol pressure medium from said unloading device to eHect loading independently oi' said checlr valve and moving said motor speed control means.

l. In a controlling mechanism for a compressor system comprising a compressor and al motor for driving the same, in combination7 movable means for controlling said driving motor, a servo ino-tor for actuating the same, said servo motor comprising a yieldable member having a surface subjected to fluid at the compressor discharge pressure, unloading means for the compressor, and means comprising a pilot valve and an element actuated by said servo motor for controlling said unloadingY means whereby unloading and loading of the compressor are controlled in response to variations in the compressor .discharge `pressure andV in accordance with the position of said motor con trol.

5. ln a controlling mechanism for a compressor system comprising a compressor and an internal combustion engine for driving theV same, in combination, althrottle for said engine, a servo motor for actuating said throttlc', sai( 'vo motorA comprising a yieldable member having a surface subjected to fluid at the compress r discharge pressure acting-in a direction lior opening said throttle, unloading means for the compressor, and con-v trolling means for said unloading means comprising va pilot valve responsive to compressor discharge pressure for delivering pressure tluid for actuating said unloading means and Vfor venting such fluid, saidV unloading controlling means providing a passage, flow Van internal combustion rengine for driving the same, in combination, valthrottle for said the same, said servo motor comprisin yieldable member havinor a surface normallyto speed.

7. In a controlling mechanism for a compressor system comprising a compressor and' a motor for driving the same, in combination, movable means for controlling said driving motor, a servo motor tor actuatin Y the same,

said servo vmotor comprising a yieldable member having a surface normally subjected to fluid at the compressor discharge pressure, unloading mechanism for the compressor,

means comprising controlling mechanism responsive to compressor cischarge pressure for delivering actuating medium to said unloading means, and means controlled by said servo motor for holding said compressor unloaded untilsaid driving motor comes up to speed. Y 8. In a controlling mechanism for a compressor system comprising a compressor and a motor for driving the same, in combination,

a.' means for controlling the speed of said driving motor, a servo motor for actuating the same, said servo niotoi' comprising a yieldable member having a surface normally subjected to fluid at the compressor discharge pressure, unloading means for the compressor having a connection to a source ot actuating medium, controlling means interposed in said connection to control said unloading imeans, said controlling means including a member actuated by said servo motor and a yieldable member independent of said servo motor and having a surface normally subjected to compressor' discharge pressure during unloading.

9. -ln a controlling mechanism for a compressor system comprising a compressor and amotor for driving the same, `in combination, means for controlling the speed of said driving motor, a servo motor for actuating g a subjected to lluid at the compressor discharge pressure, fluid pressure actuated unloading means for the compressor, a pilot valve retil) Zsponsive to compressor discharge pressure for controlling the supply of pressure iluid to .said unloading means, and supplemental means including a valve for controlling return ow of fluid from said unloading means,

saidsupplemental means being actuated by face' normally subjected lio-fluid at'the com` pressor discharge pressure, lluid pressure actuated-unloading means 'for-the-compressor having afconnection to a source-of vpressure iluid, pilot valve interposed in said connection and responsive to compressor discharge Vpressure for controlling said unloading` means, and supplemental means 'including a valve interposed inv said connection for controlling return flow 'of vfluid from said .unloading means, `said supplemental 'means being actuated by said servo motor and operating-to hold said compressor unloaded until the engine comes up to speed.

ll. "in a compressor controlling mechanism for a compressor system comprising a compressor and a `motor for driving the same, in combination, an unloading device for the compressor for unloading the same Vwhen subjected to pressure, means for controlling the supply of actuating medium to said motor, flui pressure responsive means forv actuating said motor controlling ldevice to aposition increasing the supply of actuating medium to said motor Wliensubjected to pressure, fluid pressure responsive means for actuatingsaid motor controlling device'to aposition cutting down the supply ot actuating medium to said motor When subjected to pressure, a pilot valve for controlling simultaneous supply of pressure fluid to sai-d unloading device and said last mentioned fluid pressure responsive means, said pilot valve also controlling eX- liaust'otl pressure fluid from said device and means, and means for preventing exhaust of fluid from' said unloading device until the motor controlling device is moved to substantially open position.

l2. In a controlling mechanism for acompressor system compri-sing a compressor and motor for driving the same, in combination,

an unloading` device for unloading the coinpresser, a throttle valve for controlling the supply oli' actuating medium to said motor. a device 'for automatically controlling said throttle valve, said automatic device having a surface normally subjected to iluid at the compressor discharge pressure acting in a direction for opening said throttle valve and an opposed surface, said automatic device functioningito cut down theY supply of actu-` charge pressure for controlling supply and IOL exhaust of pressure fluid to and from said and means for preventing ,loading of' said" compressor until said throttle *valve` has moved to substantially open position.

13. ln a controlling mechanism for a compressor system comprising a compressor and a motor for driving the same, in combination, an unloading device for unloading the compressor when subjected to pressure, a throttle valve for controlling supply of actuating medium to said motor, means continuously responsive to compressor discharge pressure for controlling said throttle valve, superior control means for said throttle valve comprising a fluid actuated device for taking the control of said throttle valve away from said first mentioned controlling means and moving saidthrottle valve to closed position when subjected to pressure, means for simultaneously supplying pressure fluid to said unloading device and the fluid actuated `device of said superior controlling means when the compressor discharge pressure reaches a predetermined maximum and for ventingsaid superior' motor controlling device wlienthe compressor discharge pressure reaches apredetermined maximum, and means for venting said unloading` device only after a predetermined movement of said fluid actuated device of said superior controlling means.

lil. ln a controlling mechanism for a compressor system comprising a compressor and a motor for driving the same, the combination specified in claim 13 wherein said vent means for said unloading device comprises valve means operated to open position upon movement of 'said fluid actuated device of said superioiI controlling means to a position corresponding to substantial opening of said throttle valve.

15. ln a controlling mechanism for a compressor system comprising` a compressor and an internal combustion engine for driving the same, in combination, a throttle for said engine, a servo motor for actuating said throttle, said servo motor comprising a yieldable member having a surface normally subjected to fluid at the compressor discharge pressure, unloading means for the compressor, and controlling mea-ns loading means comprising means affording a conduit for pressure fluid moving to or from said unloading means, a check valvein said conduit permitting flow of fluid to said unloading ineans and preventing return flow therefrom, means affording a passage bypassing said check valve, a valve controlled by said servo motor controlling flow through said by-pass passage, and apilot valve responsive to compressor,r discharge pressure 'for delivering pressure fluid to said conduit for actuating said unloading means and for venting such fluid by way of said by-pass passage. Y p

for said un- 16. 1n combination-,a compressor, adrivtrol the speed "ofK said compressor, a plunger y'subjected continuously to compressor dis-,A charge-pressure 'direction to increase the compressor speed,

for moving said member ina an aiined oppositelyfacting plunger yieldably Vbiased inthe opposite'direction, `and means for subjecting said last4 mentioned,

plunger to compressor discharge pressure when the latter exceeds a predetermined desired maximum and for venting pressure supplied thereto upon a predetermined drop 1 in pressure below said desired maximum. K `17. In a pumping system, a pump, a driving motor therefor, controlling means for the driving motor movable to vary the speed thereof, a plunger 'constantly sub]ected to ycompressor discharge pressure for movingsaid controlling means in a direction to increase the compressor speed, an oppositely acting combined plunger and valve member, and compressorunloading means including a compressor pilot valve, pressure operated unloading devices, and a one wz y conduit means between said pilot valve and said ing motor therefor,a member movable to conn devices, said second f plunger controlling venting of the unloading discharge i pressure responsive devices and beingv controlled by the pilot valve to slow down the compressor when unloading` is effected.

18. In a motor driven compressor system including an internal combustion engine and a compressor driven thereby, controlling means for the compressor speed including a plunger constantly exposed to compressor discharge pressure, an oppositely acting plunger constantly biased in a direction opposite to the rst mentioned plunger and having associated therewith means for supplying pressure thereto when compressor discharge pressure exceeds a predetermined desired maximum,a throttle for said internal combustion engine, and operating connec- I tions for said throttle disposed between said plungers and actuated in opposite directions thereby.

19. In a controlling mechanism for a compressor system comprising a motor, a compressor and an unloader therefor adapted for fluid pressure control, the combination including motor controlling means, a servo motor for moving said motor controlling means in one direction,

posite direction, said second servo motor having a portion thereof constituting a valve for the control of the fluid pressure for the unloader.

20. In a controlling mechanism for a compressor system comprising a motor, a compressor and an uiiloader therefor adapted for fluid pressure control, the combination including motor controlling means, a servo motor constantly responsive to compressor disand a superior servo motor l 4for moving the controlling means in the opcharge pressure acting in a direction'to 5move the motor` controlling means in a speed increa'sing direction, anda second servo motor Y for actuating the motor controlling means,

I 5 sind second'servo motor having` a pistoncomprising a valve for'the control of the Huid y pressure for said unloader.

211 n a compressor system, a compressor,

fluidn operated unloading means therefor, a

, .0` rivmg motor for said'compressor, a device *15 adapted to heoperated. by fluid pressure, and

,y 20 meansjandthe lattermeans being. constructed 11nd arranged' to control the exhaust from theother oflsald means. l Y v In testimony Whereoflaiix my signature.

25' l FRED D.V HoLDsWoRTHL.

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