US1019360A - Unloader for compound fluid-compressors. - Google Patents

Description

VV. PRELLWITZ.

UNLOADER FOR GOMPOND FLUID GOMPRESSORS APPLICATION FILED MAY 31` 1907.

1 ,O 1 9, 360. Patented Man'. 5, i912.

l W. PRELLWTZ. UNLOADER OR UDMPOUND FLUID GOMPRESSORS,

APPLICATION FILED MAY 31, 1907.

Patented Mar. 5, 1912.

' 5 SHEETS-SHEET 2.

` W. PRELLWITZ.

UNLOADER FOR GOMPGUND FLUID GOMPRESSORS.

APPLICATIGN FILED MAY 31, 1907.

Patentd Mar.5,1912.

SHETTS-SHEET 3.

' @66% @Ven/Z020 mwa' f W. PRELLWITZ.

UNLOADBR FOB. OMPOUND FLUID COMPRESSORS,

APPLICATION FILED MAY 31,1907.

1,019,360. Patented Mar.5,1912

5 SHEETS-SHEET 4 W. PRELLWITZ.

UNLODER 1FOR GOMPUND FLUID MPRESSORS.

APPLICATION HLED 14u31, 1907.

v i Patented Mar. 5, 1912.

' Y 5 SHEETS-SHEET 5.

unirsi) strarns Patriiivr orFicE.

WILLIAM PRELLWITZ, OF EASTON,"IIENIIT.SY-LVANIIA.,l ""ASSYIGNOR .TO INGERSOLL-RND COMPANY, 0F NEWTv YORK; Y., A CORPORATION OFNIE` JERSEY.

UNLOADEB FOB COMPOUND FLUID-COMPBESSORS. l

To all whom it may concern:

Be' it known'that I', WiLLiAM Pnnnmvrrz, a citizen of the United States, and resident ot" Easton, in'the county of Northampton and State otiPennsylvania, have invented a new and useful Improvement in Unloaders for Compound Fluid-Compressors, of which the following- -is a specifica-Lion.

. My invention'relates to means` for unload-` ing compound iuid compressors and 'consists broadly in novel niean's arranged to automatically unload the compressor when the, pressure rises to a predetermined point and-load the coiiipi'essoi-ivlien the pressure falls to a predetermined point, said means comprising an auxiliary receiver, the valve for opening and closing communication between the compressor and auxiliary receiver and a regulating device, such as a fluid pres-- sure governed regulator. -connected to the -back ot the auxiliary receiver valve.

My invention further consists in means' for unloading and loading the compound compressor step b v step as the pressure' rises r plane of and falls to predetermined points, said means comprising` a plurality of auxiliary receivers, valves arranged to open and close communication between 'the compressor and the auxilia ry receivers and a pluralityr of regulating devices, suchas fluid pressure governed regulators, connected to the backs of the auxiliary receiver valves for unloading and loading the valves successively as the pressure -rises and falls.

This present-invention is also directed tol the novel means above set forth applied either- Sto both the-high and low pressure cvlinders'or to the' lon'r pressure cylinder o a compound iiuid compressor.

Practical embodiments of .pressure cylinder, Fi 4 is a central vertical section through tv e fluid pressure gov- .erned regulator which is shown' in comico-- Ation with my unloading meansfFig'. 5" represents a central vertical section of the regulating valve, Fig.l 6 is a view taken in the the line A-A of Fig. 4, looking Specification olf Letters Patent.

.application sieri my 3i, 1907. serial N o. 376,703.

my inventionare represented -m the accompanying drawratented Mar. 5, 1912.

Avin the direction of the arrows, Fig. 7 is a horizontal section taken in the plane of the line B-B'of Fig. 1i, looking in the direction of the arrows, Fig. .is a diagrammatic planview showing means for unloading and loading the low rassure cylinder only of the compoundrfluid compressor, and Fig. 9 is a diagrammatic planview showing a modified arrangement of the unloading means in which two iiuid pressure governed regulators are sliovvn for unloading and loading both the high and low pressure cylinders instead of form.

Proceeding-to describe the form shown in Figs. 1 tov 7 inclusive, thelow pressure 'cylinder-is denoted by 1, theA highpressure' four as shown in the preferredcylinder by 2 and the intercooler by 3. The

pipe leadin from the low pressure cylintlie pipe leading from the intercooler 'to-the der to'the inter'cooleris denoted bye-and pipe which leads from the high .pressure cylinder to thelfinal'reeeiver (not shown), is denoted by The main discharge valves of the low pressure cylinder' are denoted by 7 and the main discharge valves ofthe high pressure cylinder by 8. It is.to be understood that the compressor is driven from any suitable source off-' power,V not shown herein. Auxiliaryrec'eivers 9 are provided for the low pressure cylinder and auxiliary receivers -10 are provided for the high presvsure cyl-inder. Valves 11 are providedl .for opening and -closing communication between 'the low pressure cylinder and the apxiliary receivers 9',.and valv'esidZareprovided for opening and closing communication between the high pressure vcylinder2 and the aux- -iliary receivers 10. Four aiixiliary receiv-A ers 9 and their valves may lie-provided for at each .end thereof. Four- .au iliary receivers 1() and their valvcsmay b provided for the highv pressure cylinder 2, communieatingl with .eachend thereof.- The hacks A the low pressure cylinder 1, communicating.

ico' I of theauxiliary receiver .'va'lvesare. brought into communication vvith regulating devices,"

such" as `Huid pressure governed '.-regulators of the form-I disclosed in= Uniteldfstates Letters Patent No.' 514,839 .dated February 18, `1894, changed to suit a. cox'n'pound compressor'-, a. general-description o the construction, arrangement and operation of which ton heads 15, 1'6 and bridge ports. 14", 14?.

"gbypi-essure upon onej or the other-of its 1F15 .to the valve -box '13 fh fou receiver pressure." The main valve 14 ispro- 60 on the auxiliary receiver valves untilaf rei?y taining the main slide'valve 14e1 having This valveboxzis provided-with ports 17,

' 5 18, leading to atmosphere'l 'and ports 19, for 1,-.' the intercooler, 20 for the' auxiliary receiver .f 'valves of the loiv pressure cylinder -and 21 -for the auxiliary valves ofthe hi h pressure 'f cyliiider. lhe `main valve 11,1 1s operated piston' heads 15,116, Vby Hujdaemiued. at

the rends ofy the -valve box through ports 22,

. .23, under the control ofen-auxiliary slide valve 2 4 in box25 which is always open n gh'4 thefpassages 26,-27. A pipe 28leads from the-receivertothe space between the main'valve iston he'ads v15, 16 so that-'this spaceand e in. terior of the. boliV 'arealways open to vided with ports arrangedto open communication from. the backs of the auxiliary reeeivei1 ,valves on,V the. high and`low pressure cylinders to atmosphere or to the receiver 25 and intercooler respectively, 'according to the position .of the valve.' lVhen-the main valve is in one position the auxiliary valves o' the high pressure cylinder-are loaded by having their backs open to receiver 'pressure 3othrough the port 21,' interior of ,boxrl and pipe 28, and the' auxiliary? 'receiverl valves of the loiv pressure cylinder are loaded having their backs open. to intercooler'pressure, through the ports 20,142 and 19. W'hen the main valve is in its other osition, the .auxiliary receiver 'valves of t e Vhigh ressur'e cylinder are unloaded by -having heir backs 4open to atmosphere through ports 2l, l-l ard 18, and the' auxiliary tje- 4o ceiver valves of the' low pressure cylinder are unloaded by having their backs open toatmosphere through peras 20, 14 and 17.4 '.lbc top of the auxiliary valvebox'25 is provided with a cylinder 25) which iscpen et the bottom to .the interior of theY said box: piston 30 is fitted to slide in the Under' 29, u/,hicii piston is arranged to move the auxiliary vulve 24 under the ini llvea'ce of: receiijfer pressure, This auxiliary 5f: vulve Qi iss-provided with upper, and lower bridge ports 31, 32, and uppetand lovver through ports 33, 34.- The main valve box 13 is pr'ovided with a port- 35- intermediate the ports '22, 23. These several'port-sarel.v so arranged that-tbe movement of the auxil- 'ligh b the-.Huid within inatically reducing "pr'essor to a predetermined extent fixed by -therela'tive capacities 'of the compressor cylinderian'd auxiliary receiver. As the'fluid 125 pressure falls inthe receiver,

lary valve '.rill control the movement of the-y mamw'alve.: T he piston 30 for-'o 'erating the auxiliary valve is weighted to iold the auxiliaryvalve in' position to leep the loa`d= determined high pressure has been-rear:l ed; hv 'means of a Weighted arm 36, the Weights 257 on -whielrnnay-be so re lated that' theI hack o'thb 'auxiliary receiver valves will 'oe-unloaded by the movement of the mainl inder and the valve of an auxill y 10 atv the other end of. the hi iliary receivers Vat theA op 'high pressure cylinder.'

-ceiver valve 'by-opening the valve ,under the'control 'of the movement of the auxili'aryvalve when said predetermined high'pressure' has been reached., In `the form being described, four of these fluid pressure governed regulators are shown, each-regulator bein arranged'to control the unloadingof a 'v a ve of an auxiliary, receiver 9 at one end of the low pressure cylary receiver gh pressure 75. cylinder. In the forni shownin Fig. 9, two fluid pressure overnd regulators only are shown, eac regulator communicating[with the backs ofthe valves of two auxiliary receivers at the opposite ends of the low pressure cylinder' and theV valves of two .aux-l psite ends of the Fig. 8,' a form is shown in' which the low' p only is provided with auxiliary' receivers and r'egu ators for their valves. The several forms shown therein are. illustrating the point'that any number of auxiliary -receivers may be" employed andv any number of regulators to suit different requirements. y The operation of the simplest forni of n'f' invention Wouldbe as. follows.l Anauxil- 5 lary receiver cfu predetermined size is con-- nected to 'the lowjpressurecylinder and'a regulating device, such 'as -a fluid pressure governed regulator, islprovided for the aux-V iliary receiver valve. When `the compre. r starts, the pressure is raised in .the auxiliary receivercorrespondin tothe rise' of p'ressure in thesys'ten. ter the' pressure has been. raised .to its regular Working condir tion, -the'auxiliary receiver valve tends to remain closed because of the ,receiver on the back oft-he valve. When the pressure has been raised to a predetermined 'high point, thel .regulator being controlled by receiver pressure Willautomat-L cally unload .the 'back of the auxiliary re- 110 eeiver valve by opening the snm'e to atmos phere, Ythus allowing the fluid under prssure to be forced from thecylinder into the auxiliary receiver on the forward stroke of the piston and to pass back frein the N auxiliary receiver into lfor the purpose of of the; valve spring, which 4is .made veryv t, is less than the pressure-on the valve .120

the. cylinder; thus auto!1 the power of the com# the regulator auxiliary re- -back ofqthe. same to receiverepressure, thus closing the ,Will` automatic'xallyload"l the 'valve and 'perniilttliiigythe compressor to 13e ressure cylinder 85 the pressure from 1'05 the cylinder on theft-A retu'rn stroke of the piston, the unloaded valve remaining open so long, as -the power,

I lloaded,-A 'the interc'ooler pressure. will fall. in= proportiont the capacity of the aux` rota-,seo Y again' pe'ratev-ndec power. 'In this;

form, ,astlie"low pressurecylinder is un iliary Itccfeivfei- L to reduce the vload on the low ressiiref-cylinder,4 the high. pressure cylin cs .takingftheliuid from the intercooler and'con1pressing it to the final receiver. While thiswould be satisfactory in scmein'st-ances, it would notbe so economical. It' would red'uoethe capacity of the machine and reduce the amount of power reuired' to drive iti the low pressure cyl- 1n er would not do 'its proportionate amount of work and there would not be as much heat abstracted. byvv the intercooler. 1t`is obvious that by varying the size of the auxiliary receiver,'t lie compressor cylinder canbe entirely unloadedY or only partially u-nloaded, dependingupon the size of the aux-.f 'iliary receiver:

o; obtain the ful-l benefit of' extracting as much. heat as possible from the fluid, it.- is preferableto use these unloading devices 1n connection withboth the h igliand lowpressure cylinders, the relative capacities ofthe auxiliary receivers for the high and low pressure cylinders being'such that with -normal pressures, each c 'linder will" have aproportionate amount o clearance, as for instance, ii' the auxiliary' re ceivers for the low pressure cylinder reduce its capacity one-third the auxiliay receivers for the high pressure cylinder will reduce its capacity 'one-third. With this arrangement the intercooler pressure wouid remain-'substantial'ly constant and each cylinder would be compressing the same number of compressions, t-hus producing the most economical results'. If it is desired to unload' the compressor step by step, a plurality of sets of' auxiliar .receivers areprovided for the high and ow pressure cylinders and the regulators for the different auxiliary receiver valves are set by means of varying their weights 37 to successively unload the auxiliary receiver val-ves as the fluid pressure rises-to :predetermined points and load vsure falls and this is a valuablefeature ofmy inventiornas .it eliminates' all shocks' to the machine .asthe load is thrownV on and backward loadsA onv the machine' 4 nearly uniform wouldbe to first ,simultaneously un- -load one auxiliary receiver valve at the of the high pressure cylinder and then sil multaneously unload the auxiliary -receiver compressor, o auxiliary receiverstherefor,

` valves for opening or closing communication valve at the back end of the low pressure cylinder and the auxiliary receiver valveexpanded. lftheunloaded valves' regulating device I wish to include 'an .sively attained' pressures. oi. One way of. accomplishing this result Y 3. The comb'n'ation-vviththe highandflow and at the same time keep the-forward and -or closing. communication between the cylwill beagain given backto1the-machineolii" the return stroke as the volume of fiuidjs close at'the end of the piston strokefaiyay from said valves, due to the reduction-f ff 'im pressure below the power of their sp'ril i'fzjsgf'"f1 they will be opened again assoon as thepisr ton starts toward saidvalves and'will' 'r` ""`8f0 main open until the/pressure in the'auxliai'y working with; the- 'auxiliar-y receiver valves closed,- it will "be seen that-the auxiliary. receivers remain full of fluid atmaximum pressure as the valves l prevent-the iuid from passing back into the,` cylinder. A Attcntionis called tomy co-pending ap'' plication'led of even date herewith, Serial No. 376,702, in .which nnuaire. pendinggf* "if directed-to 'the loading and unloading` flu-id compressors of any typeby a ntnie'l".`-

means while this present application isidi- 95 rected toA the loading and-unloading ofa L compound fluid -compressor of any type' similarfmeans.

It is to be understood that by the term 'T100 mechanical, electrical or' fluid means'whic can be employed for carrying out the ob-' jects of my invention; hen-ce I do not wish1 to limit myself tothe particular regulating del vice hcreinshown and described, but )05 What I claim is: j 1. The combination. with the high and low. pressure cylinders of a compound iiuidcompresser, of auxiliary receivers therefor, and means for opening or closingcoinrrmnication between the cylindersand their auxiliary -receivers at successively-attained ressure's.

. 2. The combination with the igh-.and-lowpressure cylinders off a; ccmpoundiluid'comfpressor,' o auxili ary receivers4 tlu'arefor, and 1.i6 fluid pressure controlled;means:foropening` or closing communication between the cylin-` ders and'theii'. auxiliary receivers atv succes-j 12e pressure cylindersof-za'compoundlluidzcom-- 'I pressor, of auxiliary receivers therefor, a nd, fluid pressure controlled valves for openlng inders and. their auxiliary receivers at suc-v cessively attained pressures.

receivers. is. reduced to a -pointbelow the@` e betiveen the cylindeisand their tained pressures dd 0 :fofthe-valves forl successvel 'means u 'ndependentof' the p uirrping mechanism'for unloading it in sucingit in successive well 9- Illacompound-llmd comprcssonthe,

compressor, o

auxiliary receivers at successivelya unloading devices for the said-valves.

5. The combination' -with' the' highand low pressure 'ylinders of 'a compound {luidceivers at successively attained pressures and.

#fluid pressure controlled unloading devices 'forftlie-said valvesf Joundfiiuid compressor, the.

6 In`a com; combination with I pumping mechanism, fval'ves of the 'L In 'a compound fluid compressor', the

.combination -ivith' 4.pumping mechanism, of fluid .pressure controlled means independent` ofthe valves of the pumping mechanism for unloading it in Asuccessive well defined steps.

8. In a compound fluid compressor, the combination .with pumping mechanism, of

i means, independent of the valves. of the pumping meelxanisnifor loading or unload' defined steps.

combination with4 pumping mechanism-,Tof fluid pressure controlled means independent of the valvesof. .the pumping mechanism for loading en -unloading' 4it iii-successiveiivell defined steps.

10. The combination with the cylinders of a compound iiuid compressor, of unloading devices` indepe ndent of the compressor valves, fitted to operate at different succes'- .,1I, .L. Th e combi ationwitli thevcylindcrs of a compoundiiuid compressor, of fluid pressure ,controlled unloading devices .independent of the compressor valve's, fitted to operat at different successively 12.-l.'l`he combination-with the .low pressure cylinder of a compound fluid compressor, of auxiliary receivers .iherefor, valves for openingnml closing coinii'ninication be ltween the low pressurel cylindcuand the auxiliary receivers and means connected to thc backs ofthe valves for successively unloading t li em as different predetermined high pressures are reached. i r13,; Thejconibination with siirecy-lindei of a compound fluid compres sor, of auxiliary receivers, therefor` .valves for opening andelosing communication between, the lowprcssure cylinder and the auxiliary receivers `and fluid pressure controlled' means connected to vt-lie backs of the valves unloading'them as different predeteriiiiii'cd high pressures are reached.

cylinder of a compound Lfii'ild compres.-

auxiliary receivers therefor,f valves for opening or closing communication between the cylinders and their auxiliary relow pressure'cylinder and the'auiluir 'receivers, andregulators connected t tiling ack werden asdilierentfpredeterinine 'j' high are reachcdxf n 15. The combination .with the low pres-- sure 4'cylinder o a' compound Huid compress'onimof auxiliary receivers,l valves .for :opening and closing communication befw f, .the loiv pressure cylinder and' the aux'ili i; receivers, and Huid pressure goverxiwu latorsconnected to the backs of the -va ves for successivelyunloading them as different predeterminedhigli pressures are reached 16.' .The'combinationwith the lopr pressure; '-80 :cylinder of a compound fluid compissqryoff determined ,ingtlie ,valves as the' pressure falls to prds i .ccivers, and'iuid pressure controlled means fpressure rises to for successively loadingthe valves as `t`lie-.;' Epressure falls to -automatically un compressor step by'step.

'sure .cylinder 4and the auiiilia 'and regulators for. successively unloading 'the valves as ihe'pressure rises to predeter' )attained presmined points',

the -loiv pres;

. auxiliary receivers tlierefor,'valves for`o1ii i`\j ing and closing communication lietweentlie? glow pressure -cylin'derand the auxiliar yre-' '.ceivers," and means for A-sujiqzessivcly un cada' g5 ing the valves as the pressurerises to pre` points and for successively load- =tei-mined points, for automatically unload-.

17. The combination 'ivitlitlie low pressure auxiliary receivers therefor, valves for opening and closing communication between the low pressure cylinder and the auxiliary refor successively unloading the valves as'the i predetermined 'points and predetermined points; for lng oading and yloading thes'f- 18; The combinationwith loiv pl-feiire cylinder of a compound fluid.compresso`r, of auxiliary receivers, valves for ohpening and Iclosmg communication between t mined-points and for successively loading 11o the valves as the pressure -falls to predeterfor automatically unloading. and loading the compressor step by step.

19L The combination with the low pressure cylinder of a-eoinpound fluid compressor, of auxiliary receivers, valves. for opening andclosinglr communication between the low pressure cylinder and the' auxiliary receivers, and fluid pressure governed regulators for successively unloading thevalves Ias the res- "sure rises to predetermined' points fori'.

` successively loading the valves as the ,pressure falls to rcdeterminedfpointsrfor auto` 4 pressor step by step. 20. The combination witli tli'e"higli and low pressurecylinders eta. compound fluidi.

compressor,of .auxiliary receivers therefor? valves'for openin tand closinglcommnca-r :ing and loading the compressorstep by step,

'matically un oading"' and loadi'iiggtli'e contr;

Afor unload ilng the compressor step. by step.

21. The combination with-the` high and low pressure .cylinders of a compound fluid 'compressor, oiauxiliary receivers therefor,

valvesfor opening and closing c o'nnnunieation between the high and low pressure cylinders and their auxiliary receivers and fluid pressure controlled means connected .to the backs of theV valves for successively unload-y ing them as dillferent predetermined *high pressures are reached, for unloading the con'xpressor step by step. A

22. The combination with the high andlor pressure.cylinders of a compound fluid compressor, of auxiliary receivers, valves for opening and closing.communication between the cylinders and their auxiliary receivers and regulators connected .to th'ebacksof the valves forl successively unloading theml as different )rcdetermined high pressures arereached, or unloading the compressor step bystep.

23. The combinationwith the'high and low pressure cylinders of acom'poundiluid compressor, of auxiliary receivers, valves' for opening and closing communication between the cylinders and their. auxiliary receivers,- and fluid pressure governed regulatorsfcon-l nected to the backs of the vvalves or'succesv' sively unloading them as difierentprede' termined high pressurcs'are reached, fofr pnloading the compressor stepby step.-

24. The combination with 'the high and lour pressurecylinders of a compound-fluid compressor, of auxiliary'receivers therefor, valves for opening and. closing communication between the hlgh and loirA pressure cyl-I inders and their auxiliaryrecelversl and means for' `successively unloading-the valves as the pressure rises to predeterminedfpoints- Aand for successively ,loading the'gyalfves as the pressure talls to predetermlned.;points, the

The combination with the high and low pressure cylinders of a. compound fluid compressor, of auxiliary receivers therefor,1 .valves -for opening and closing communica- A tion between the high -and low Hpressurecyl? I inders and their receivers and.

uid pressureA controlled means' ffor' successively unloading the. valves as-tl'ie-'pressure rises to predeter# mined points and for successively loading' the valves the pressure fallstm-predeterf lmined points, -ior automatically unloading' andloading the compressor step by step.

26. The combination with the high and loir pressure cylinders of a compound fluid compr ssor, oit auxiliary receivers, valves for upenn ,f und closing communication' between and 4regulators for successively' unloading the valves as. the pressure rises' to predetermined poin'tsand for successively loading the valves as the pressure falls to predetermined points,y for autr'miatically unloading and loading the compressor step yby step.

27. The combination' with the high and low pressurevcylinders 'of coin-pound zfluid compressor, ofauxiliaryreceivers, valves for cpenin r and-closing communication between t-he cy i.ndcrs.- and' theirauxilia'ry -receivers and fluid, pressure governed' regulators for successively unloading the valves as thepres- .su're'rises 'to predetermined points and for successively loading'the valves as the pres` sure 'falls lo'predeterinined points, for automatically unloading and loading the" com- `pressorstep by step.

28. The'combination with the high and low pressure cylinders of a compound fluid compressor, Qf-a" plurality 'of auxiliary reoeiversfor ea'clr cylinder,y valves for opening and closing communication between the high andV low pressure cylinders-and their auxiliary-receivers' and means connected to the backs of. the valves for successively unloading them-as' diierentv predetermined high pressures'a-e reached, rer unloading the compressor step byste'p, r

' 29."'l`h e combination'\vitl1"tl1e"l1igii and glow; pressure.cylinders of a :com pound ll uid compressor', `olf-a"ilurality of auxiliary receivers for each cy inder, valves fr opening .and closingr communication between the high 'and .-loiv ,pressure cylinders andfthei r auxiliary receivers and fluidr pressure controlled means connectedY to tlie backs. of the valves .for successively unloading them as 'diil'erent predetermined high y pressures are.v reached, Afor unloading the compressor step by step,

. 30.*The. combinationff with vthe high and low pressure cylinders-oi?4 a compound -fluid compressor, of a plurality of :auxiliary rcceivers for each cy inder, val ves Torf'opening and closing communication -betwccn' the cyl'- inders and theirl auxiliary receivers, and regulators connected -to the backsiof "the valves for successivelyunloadingthem as vdilferentpredetermined high pressures. 'are reached, for unloading the compressor step by step.

low pressure cylinders of 'a compound fluid compressor, olf-a -plurality oauxiliaryipcthe cylindersand their auxiliary receivers compressor, of a, plurality4 of auxiliary re- '3.1.' The combination with the high and,

ceivers foreach cylinder, valves for opening i and closing communication between the high and low pressure cylinders and their auxiliary receivers and means for successively unloading the valves as the pressure rises to predetermined points and for successively loading the valves as the pressure falls to redetermined points, for automatically unoading and loading the compressor step by ste 3. The combination with the high and `lovv, pressure cylinders of a compound fluid compressor, of a lurality of auxiliary reoeivers for each cy inder, valves for opening and closing communication bet-Ween the high and low pressure cylinders and their auxiliary receivers and Huid pressure controlled means for successively Vunloading the. valves 'asthe pressure rises to redeterinined points and for successively loa ing the valves as the pressure falls to predetermined points, for automatically unloading and loading the compressor step by step.

B4, The 'combination -With the high and low pressure cylinders of a. compound i'iuid compressor, of a plurality of auxiliary receivers for .each cylinder, valves for .Opening and closiiil communication between the cylinders an their auxiliary receivers, and

-.regulators for successively unloading the valves as the pressure rises to predetermined points and for successively loading the valves as the pressure falls to predetermined points, for automatically unloading and loading the compressor step by step.

35.The combination with the high and low pressure cylin ers of a compound iiuid compressor, of a lurality of auxiliary receivers for each cy inder, valves for o ningv and` closin conimuni'cation'between t e cylinders yan their auxiliary receivers and Huid pressure overned re ilators for suc! cessively unloa ing the va .ves asthe pres- Q' sure rises to predetermined points and for successively loading tlie valves as the presfsure falls to redetermined points,l for-auto'- Amatically u oading and loading the com- .presser s tep by step.

`,'36.'The combination with v lowpressure cylinders of a compound fluid the high ana-- Y `pressure controlled means for openingand closingcommunication between the cylinders' and their auxiliary receivers, the` relative capacities of the auxiliary receivers of the high and, low pressure cylinders being so proportioned that the intercooler, pressure will remain substantially constant.

38. The combination With-the high andlow pressure cylinders o'f a compound fluid compressor, of a plurality of auxiliary receivers for each cylinder the relative capacities of the auxiliary receivers of the high.

and low pressure cylinders-being so proportioned that the intercooler pressure Will .res-v main substantially const-ant and means for simultaneously opening and closing -communication between each'of theeorresponding auxiliary receivers and its cylinder.

.39. The combinationwitli the higi'iand low pressure cylinders of a compound fluid compressor, of a plurality of auxiliary receivers for each cylinder the relative ca acit-ies of the auxiliary receivers of the iigh and low pressure cylinders being so proportioned that the intercooler pressure will remain substantially consta-nt and iuid pressure controlled means for simultaneously opening and closing Acomii'iunication between each-of the corresponding auxiliary-receivers and its cylinder i `fI'n'testimony, that l claim. the foregoing.

as my invention, I 'liave signed my naine in resencelof two witnesses, this 25tlr day ofj Wnliimn: PRELLWITZ.

F. GEORGE BARRY,

HNBY THIEME.

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