CA1166073A - Two-component metering pump - Google Patents

Abstract

Abstract of the Disclosure A porportioning pump with tandem diaphragm pumps each having a pumpage chamber connected with a source of supply and a mixer and dispensing nozzle, a piston pump for operating each of the diaphragm pumps, a common eccentric drive for the pistons of the piston pumps, the piston pumps having cylinder wall sleeves extending into the hydraulic fluid reservoir, the sleeves having refill ports therethrough communicating between the pump chamber and the reservoir, one of the sleeves being longitudinally adjustable, a double threaded rotary control for the longitudinal adjustable cylinder wall sleeve, bypass pressure relief valves and passages for the hydraulic fluid from the pump chambers returning fluid to the reservoir in the event of excessive pressure, and the pump motor having a variable speed drive for widely varying the speed of the pump.

Description

~J ~073 ThlS invent.ion relates to variable diaphragm type meter~ng pumps, ahd more particularly, to an adjusta~le pump which is well adapted or accurately and adjustably supplying metered quant.ities of a two-component product.

ackyround of the Invention One comrnon usage oE metering pumps is in the measuring o~ components of multl-component products, such as paints, resins, and floor coverings, and also in adding small quantities of concentrate to water as in fertilizi.ng and sprayin~ herbic.ides onto crop fields.
It i.s readily apparent that with such widely different usages, numerous ~equirements ar~ encoulltered as to maJce very suhstantial demands upon the capability of the pump.
Al~hough a two-componen~. metering pump has been known previously, inherent construction features clearly limit the usefulness in certain situations. Metering capability has been provi.ded by mechani.cal.l.y limiting the return st.roke of the piston. See UOS. Patent 3 7 612,727O
In limitin~ the rekurn s~rolce o the pi.s~on, the piston encounte.rs a mechani.ccll stop which sudd~nly absoxbs the inertia o~ the piston, any assemblies connec~ed w.ith it, and the diaphragm-operatin~ hydraul.ic fluid or oil.
The revolviny cam will ini~ially lif~ o~f the stopped piston and then imp~ct the piston again to suddenly start it into motion. Vepending upon the shape of the cam and the time in each cycle at which the cam reengages the piStvn, the repeated impact of the cam ayainst the piston and the repeated impact of the pis~.on ayains~ the .~ stop can create subs-tantial vihration in the pump~
Other single component ~iaphragm type metering ~umps have usea other types of mechanisms ~ox varying~the pumping rate. For instance, one pump has a poxt .in the ,~.

piston for suddenly releasing pressure in the cylinder at the end of the pressure stroke, as the piston port passes by the end of a stationary and adjustable rod, see U.S. Patent 3,285,182. Another pump varies the length of stroke of the piston by varying the eccentricity of the driver for the piston, see U.S. Patent 3,374,750. Such varying of eccentricity involves complicated mechanisms; and relying upon relief of developed pressure at the end of the pressure stroke requires a rather complicated mechanism and the developing of vacuum pressures on the return stroke which cause related complicating problems.

Still other diaphragm type pumps show the basic separation between the hydraulic fluid pumped by the reciprocating piston and the other liquid pumped by the diaphragm. Excess pressure under certain circumstances is relieved in various ways in these pumps and of course refilling of the cylinder after such relief is necessary.
See U.S. Patents 2,578,746; 3,075,468; 3,254,845; and 3,680,981.

Brief Summary of the Invention .

An object of the invention is to provide an improved two-component diaphragm pump to simply and effectively vary, over a wide range, the quantities of `components pumped.

The variable diaphragm pump has as an adjustmen~
control and proportion-varying apparatus facilitatiny extremely accurate adjustments of the quantities pumped, these adjustments being accurately repeatable.

In a preferred embod.iment of the invention the two-component proportioning diaphragm pump provides for relief of the pressure of the pumping hydraulic fluid when flow of the pumpage is suddenly stopped, and prevents relief of any of the pressure of the hydraulic fluid during normal operation and flow of the pumpage to the dispensing nozzle.

In another preferred embodiment of the present invention the two-component proportioning pump has tandem diaphragm pumps each operated by a separate piston pump with a common drive and an adjustable sleeve forming the cylindrical wall of one of the piston pumps in order to obtain the desired proportioning at the diaphragm pumps.

In another preferred embodiment o~ th~ invention the two-component proportioning pump utilizes tandem diaphragm pumps and piston pumps to operate the diaphragm `` pumps, one of the pistons operating in an adjustable sleeve with a refill port therein communicating directly with the common reservoir of pumping oil, the sleeve extending well into the reservoir with its exterior exposed to the reservoir while ~he piston extends into the interior ' thereof.

Another feature of a preferred embodiment of the present invention is the provision of a variable speed ,~
s`-~ characteristic in the two-component proportioning pump for 1 ~6B073 controlling the quantity of pumping by both of the diaphragm pumps and with control apparatus for changlng the relative pumping capabilities of the two diaphragm pumps to obtain correct proportioning of the pumped liquid.

Another embodiment of the invention has a double thread adjusting arrangement on an adjustable sleeve forming the cylinder of a piston pump operating the diaphragm pump.

In the two-component proportioning pump embodiment of this invention utilizing tandem diaphragm pumps, the diaphragms are of a sandwich construction of Buna-N rubber C at the oil side of the diaphragm and Teflon at the pumping side of the diaphragm to resist deteriorating effects of liquids being pumped and the sandwiched diaphragm has annular inner and outer sealing beads confined in grooves in the housing and the piston-operated stem attachment. The diaphragm pumps, can be driven by either a rotary eccentric or by another fast acting reclprocating drive/ such as a piston type pneumatic motor.

A principal advantage obtained by the present invention is the accurate metering of a quantity of liquid being pumped and permitting the quantity of liquid to be varied considerably and without allowing any undesired vibrations to be set up in the pumping assembly, regardless of the pressure and speed involved.

I

3a ~`T~ k . i ~ ~6B07 3 Brief Description of Drawings Figure 1 is a diagrammatic plan view illustrating khe invention.
Figure 2 is a longitudinal section view taken on an up-right plane as indicated approximately at ~-2 in Figure 3.
Figure 3 is a longitudinal section view taken approxi-- mately at 3-3 in Figure 2.
Figure 4, which appears on the first sheet of drawings, is an enlarged detail section view taken approximately at 4-4 in Figure 3.
Figure 5, which appears on the first sheet of drawings, is a diagrammatic plan view showing a modified Eorm of the invention.
Figure 6 is an elevation view, partly in section, of a modified form of proportioning pump.

Detailed Specification The varia}:)lc two-component pump i5 indicated in ~eneral by numeral 10 an~ i6 illus~ra~ecl in Figure 1 to be ' typicL~lly used to supply thc pumpacJe to a mixer 11 from - 20 which the mixed,components are conveyed by a long hose 1 - , to an airless sprayer 13. It should be recognized that supplemental equipment may be employed be~ween the pump 10 and ~he mixer 11, for accomplishing such functions as heating and filteLing the pumpage. In one typical usage, resin is supplied f'rom one source 14, and ca~alyst ls supplied from ano-ther source t.allk 15.
.~ rotor 16 provides a rotary source of power for the pUIilp 10 and is connecte-l through a variable speed pull~y 17, bclt 1.3, ar!d pull~y 19 to th~ input shaft 20 of ~he pump.

J
'~,S~ .

In the form of pump lll.ustrated in E'igures 2 and 3, ~he pump l0 has` a hcusing 21 which defines a central chamber 22 de~i.nincJ a reservoi.r for hyclraulic ~luido The shaft 20 is mountecl on bearings 23 and 24, and clefines an eccentri.c 25 whi.ch includes an eccentric portlon 26 or' the shaft 2U which .is embrace~ by a ball beari.ng 27, the outer annular periphera~ surface 27a o~ which gyrates as an eccentric around the ro~ation ax~.s of the shaft 20.
The pump 10 includes a pair of diaphragm pumps ,~8 and 29, and a pair of piston pumps 40 and 4].
The two cliaphragm pumps ~8 and 29 are essentially identical to each other r and iclentic,al reerenc,e numerals are used for bothO The housing 21 has recesses 21.1 and 21~2 receiving the frame blocks 30 of the di.aphragm pumps.
End covers 31 a~e affixed to the housing ~.l as by cap screws Eox capturing and clampiny the frame blocks 30 in stationary position~
The diaphracJm pumps ~8 ~ncl 29 have pum~age chambers 32 ancl hydrauli,c ~luid pumping chambers 33 on opposite 20 sides o:E diaphra~ms 34.
di.ap~lragm s~em 35 is attached b~ clampincJ -to the c,e~:er OI the alnu:lar ~llaphrclgm 34, and ext~nds irli'~O the SUppl'i' duct 36 ;.Il fralnc-, blo~.k 30 which col~nuni~ates w~ h t:he hydraulic flu:i.d c~hclmber 33. A comE)ressio~l spring 3'~
, 25 has one end b~arincJ a~ainst a shoulder in the frame blocls 30, and the other end bearing against a washer 38 an~hored to the free end of ~he diaphragm stem 35 as by a refaining screw~ The diaphragm stem 35 is guided by a statioIIary bearing sleeve 35.1 in the supply duct 36 and spaced from the ~rame block 30 by a spider-like moullting.
The cliaphragms 34 are of annular and laminar construction, with a lamina 34.1 o~ neoprene rubber~
faclng the hydraulic fluid chamber 33~ ancl a lamina 34.2 of a substantially inert plastic such as a pla.stic known 3~ by it.s ~rademaxk M~LAR, or oE another plas~ known by its ~ ~66~73 trademark T~FI,ON, mo:re spe~c:i~i.cally polyfluorotetra-e~hylene~
The cliaphragms 34 have annl1lar bead; 34.3 at their inller peripheries~ and annular beads 3~.~ at their outer periphexies.
The outer beads 3~.~ o the dilpllrac~ms fit into annular grooves 3().1 in thc? frame hlocks 30; and the inner beacls ~4~3 f;t :i.nt.o a;~IIular grooves 35.2 .formed in the clc~mping head 35.~ Oll the e~ncl of the cliaphragm st:em 35O
The inner ~e~r:~phery of the diapll:ra~m 34 i5 ClalTlped aCtail~st the head .~3 by a clampi.ll~ d~ c 3~ ret~lined onto the end of ~he di.aphragm s~em by a screw 3'3.1.
'l'h~ pumpage chambers 32 of the ciia.phragm purnps 28 and 29 are connected throug}l ~i-tti.ngs ~2 ~nd 43 which are ~5 respectively prov.ided wi.t.h inf'low and outf 10~7 check valves 44 and 45 thxou~h ~hich the~ pumpa~e is directed into and out of the pumpaqe chambers 32. The fitti.ncts 42 are connected to supply flow l.ines 46 and ~7 from the two sources of mat.erials to be mixed; and the discharge fi-ttings 43 are connected to the discharge hoses ~8 and ; 49 which suppl~ the components -to the mixer 11.
~he diaphractrn purnps 28 ancl 29 are re.spectively operated by hyclrauli.c Eluid pumped from the pi.slon pumps 40 and ~1. The piston pumps ~0 ancl 41 have reciprocatin~
pistons 50 and 51 which h;lve hearing heads 50.1 and 51.1 which bear arJainst the peripheral surface 27a of the eccentric. Coil springs 52 and 53 bear a~ one end agai.nst a shoulder o~ the hou~.;in~ 21',and bear against the heads 50.1 and 51~1r respectively, of pistons 50 and 51 to continually urge the ~istons against the peripheral surface of the eccelltric.
The cylinders 54 and 55 in ~lich the pi.stons 50 and 51 reciprocate are de:Eined by cyllnder wall sleeves 56 and 57, respectively. Cyl.inder wa:Ll 57 is stationa.ry in the houslng 21'and is c~alnped ~y -the ad~acent frame 1 1~6~73 block 30 so that a shoulder 57.1 abuts agaillst an adjoining shoulder .in the housing 2:Li. A sic3nlfi.cant lerltJth o: the inne~r encl of the cYylinder wall sleeve 57 ex-tends into the hydraulic fluid reservoi.r 22 whicll su:rrounds tile outer per.iphery 57~2 of the inner portion of the cylinder wall sleeve 57. ~ pai.r of ports 57~3 e~xtr~-3nd throut3h -the cylinder wall sleeve 57 and communicate at their inner ends with the pump chc~mbc3r or cylinder 55, and at tlleir outer ends with the reservoir 22.
.It will be no-ted tha-t l~he spring 53 closely embraces the outer peripht-3ry of the cylinder wall sleeve 57.
The inner encl 56.1 o~ the cylinder wall sleeve 56 also extt-~nds a sign.licant distance into ~he reservoir 22, and ports 56.~ through the cyli.nder wall sleeve 56 provide communication between the pu~ in~ chambex or cylinder 54 and the reservoir 22 at the outer periphery of the ~lee~e ; 56. Sieeve 56 is snu~ly mounted in a bore 21.1 of -the housing and is long:itllc1ian]..ly slidable -therein. The sle~ve 56 has a closed head portioII 5G.3 which has a longituclinal ];e~way or groGv~.3 56.~ ~herein. ~`kt3yin-J pin 5~ is thr~.3aclc3d in the housing 21 and e.~.-kent~ls into the keyt~7a~ 56.~ for gllid.i.ntJ the cylinder wall 56 in its longitudinal movement withoul.: perlnltt:i.n(3 any rotation of the sleeve.
The cylinder wall sleeve 56 is provided with a stem 56.5 hâvi.ng threads 56.6 on its outer periphery.
The stem 56~5 is ~hreaded into a ro~ary control in the .Eo~n oE a ~leeve 59 having a knurled head 60 a:Efixed ~hereon. ~he rotary control 59 has a threaded exterior surace 59.1 which is threaded into a boss 61 formed integrally o the housin~ 21~
The threads at both the inner peripherv and the outer periphery of the annulax rotary control 59 are both righthand threads, but they have a different pi.tch.

lL~6~;~73 --1.0--At the oute.r pexiphery of the rotary control 59, the threads by which ~he rotary control 59 .is connected to the boss 61 of the housing has an 1~ pi-~ch in the forrn illustrated. The threacls at the inner periphery o~ the rotary control and on the stem 56.5 have a 24 pitcho Accordi.n~l~, turniny the rotary control 59 and 60 th~ough . a significar2t arc of rotat.ion, will produce only a ver~
l.imited endwise movement of the stem 56 5 and of the cylinder wall sleeve 56.
he cylindex wall sleeve 56 has a plurality of larcJe flow ports 62 thereth.rough for open con~unication with ~he duc~ 36 which communicates w.lth the h~vd.raullc fluid chamber 33 of the adjacent diaplhragm pump 28~
Pressure relief or bypass pas~ages 63 and 64 are provided in the housing 21 to allow hydraulic ~luid to ` r.etllrn from the pump chambers 54 and 55 to the reservoir 3-~' ~ under certain condit.ions, such as when the spray nozzle 13 is suddenly closecl so as to prevent any pumpage from moving out of the pumpage chambers 32 of the diaphragm pumps. Pressure rel.ief valves 65 are provided in the bypass passages 63 and 6~ ancl are substantiall~
identical with each other~ Each of the p.res~ure relie~
valves has ~ valve elemen-t 66 urged by a spriny 67 against the valve seat 68 .so as to keep the pressure rellef valve 65 closecl un~il pressure i,n the acljacent pump chamber exceeds a predeterrninecl minimum. The tenslon on the spring 67 is main~ained and adjus~,ed by an anchor 68 threaded into a mounki.ng pluy 69 which is ~hreadably connected to the boss 70 of ~che housing 21.
Comrnunication is provicled from t~le pump chamber 54 into the pressure relief valve fi5 in the passage 63 through an annular manifold groove 71 in housing 21 and extending entirely around the outer periphery of cylinder wall sleeve 56 adjacent the ports 62. The manifold groove 71 also communicates with the d~ct 36 through which .

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hydxaulic i.`luid is suppliec.1 to t.he hydratllic ~luid chamber 33 oE tlle diaph~agm pump 2~.
: Th~ cylindel wal.l sleeve 57 has similar ports 62.1 which provide flow communica-t.ion i.nto an annular man:ifold groove 71.1 to allow the hyclraulic Elui.d to enter the b~pass passage and pass by the relief ~al.ve 6S in the event of eY~cessive pressures.
In operatioll, the motor 16 is operated ancl the variable speed pulley 17 ls adjusted as to produce rotation o.[ the shaft 20 at a speed withln the rancJe oE approxi mately 200 to 1200 rpm. The quantity of pumpage from the two diaphragm pumps 28 and 29 may be ~aried over a w.ide range by changing the speed of the drive shaft 20.
Changing the speed will chan~e the pumping rate of -the two diaphragm pumps in substantially direct relati.on to the speed of the drive shaft. In add:ition, the pumping rate of the diaphra~m pump 28 may ~e changed by adjusting the hand control 60 as ~o procluce longi.tudi.nal reIocation of the cyllnder wall s.1.eeve 56 and o~ the port 56.2~
~s ~he shaft~ 20 revo].ves, -the eccentric produces reciprocation o~ -the pistons 5Q and 51. The pistons are almost entirely confi.ned i.n the cantiliver end porti.olls of the cyl.inder wal:L s:Leeves 56 ~nd 57 whi.ch project into : the reservoir 22.
~s the p;.ston 50 proyresses frGm the position illustrated in Fi.cJures 2 and 3 in an outward directiorl along the cylinder wa:Ll sleeve 56, the leading face of the piston 50 will initlal:Ly move across and then close the ports 56.2 in sleeve 56. Until the ports 56.2 are entirely closed, the pumping stroke of the~ piston pump 40 does not commence. At the instant the piston 5q closes the ports 56.2, pumpln~ act.ion commences, and the hydraulic fluid commences to ~low through the ports 62 and duct 36 ~; into the hydraulic fluid chamber 33 of diaphragm pump 28.
As the hydraulic fluid in chamber 33 moves the diaphragm ` ~ ~166~73 34~ pumping of the l.iqu:id in the pumpage chambe.r 32 commences~ and continues until the eccentric completes the outward movement of the piston 50. As the piston 50 stops and ~hen starts returning inwardly under the influence of spriny 52~ the spring 37 of diaphragm pump ~8 draws ~he diaphra~m -toward its rest position; and simultaneously, the pumpaye chamber 32 i5 again refilled with the licluid from -the source 15~
Simultaneously as the eccentric is dr.iving the 10 piston 50 outwarclly, and subsec~uently as the spring 52 returns khe piston 50 to the position sho~n in Fiyures 2 ancl 3, the other piston 51 i.s also being moved. InitialLy, from the position illustrated in Figures 2 and 3~ -the piston is moved under the influence of spr.ing 53 in an inward cl.irection as the eccen-tric revo].ves to allow such inward movement. The movement of piston 51 permits the spriny 37 to draw the diaphragrn 34 toward the hydraulic fluid chamber 33, and simultaneously the p~page chamber 32 is b~ing enlarged ~o draw liquld from the source 1.4 for the nex~ pumping stroke~ During the normal operation of the pump wllile the nozzle~ 33 is open so tha~ botll of the diaphragm pumps 28 and 29 are ~ull~ ope:ratiIIg~ there will be no ~low whAteve~: throuyh the bypass passayes ~3 and 64, and the valves 65 remai.n entire:Ly closed.
In -this circumstance, there is essentially no flow through the ports 57.3 of cylinder wall sleeve 57 and ports 56.2 of cyl.inder wall slee~Je 56~ because there has been no ~oss of hydraulic fluid from the pump chamhers 54, 55 duriny the normal operation of the piston pumps. If ~here i5 some srnall loss of hydraulic fluid due to seepage along the piston or otllerwise, the hydraulic fluid in the pump _~ chambers S4, 55 will be replenished duriny each stroke of the pistons ,hrough the poLts 56.2 and 5~l.30 The advantagesof extendiny the cylinder wall ~5 sleeves 56 and 57 well into the reservoir 22 are numerous.

~16~073 -:L3-The refill passac3es or po:rts 56.2 and 57.3 axe extremely shor-t, equaling tlle thickness oE the cylinder wall sleeves 56 and 57. Therc is no neecl for purposes of the refill to ut.ilize long and complic2ted passayes in the housing 21. Construction of tne pi5ton pumps 40 and 41 is simple by virtue of the remo~able cylinde~- wall slee~es so that in the event any mai.ntenance or adjustment as to cylinder and piston size is desired, the cylinder wall sleeves can be readily repl.aced. The proportions of the 1~ materials b~ing pumped may be very accura~ely con..rolled by adju.s~ing the rotary control 59, 60O The slightly di.fferent pitch on the threads at 56.6 and 59~1 allows the rotary control. 6~ ~o be revolved -thro-lgh a significant.
arc for a small amount of lonc~itudinal mo~ement of the sleeve. Because of the careful control of the longitudlnal movement of sleeve 56~ the :rol:ary control 59, 60 can allow the setti.n~ o:E the sl~eve to be repeated duriny sequential pumplng oper:ations. As illustrate~ in Figure 2, a scale may be provicled arollncl the peri.phery of the hand wheel 60 and on -the boss 61 to produce a ve.~nier scale.
Somc mate.r:i.als be.i.llg pumpe~ may vary from bat~h to batch or with the temperature cc~rld:ition.s and tlle adjustment o:E cylincler wall sleeve 56 can minutely aEtect the quantit~ of malexial pumped by the diaphragm pump 28.
.~t.i.mply chany.incJ the ].ongitudinal posit.ion of the cylinder wal.l s].eeve 56 causes the ports 56.2 to assume a new position 50 as to cau~e the piston 50 to change the phasing o~ closincJ of ~he port 56.2~ whereupon to actually change the amount of hydraulic fluid moved in and out of the hydraulic ~luid chamber 33 of ~he d.i.aphragm pump.
In the event that the dispensing nozzle 13 i5 suddenly closed to stop the flow of ~he pumpage ~roM ~he two diaphragm pumps 28 and 29~ the hydraulic ~luid from pump chamber~ 54 and 55 is no longer capable of moving the diaphracJms 34, and accordlngly~ ~xcessi~e pre.ssures 1 1~6~73 .4-are immec1iate1y created in the pump chalnbers ~4 ancl 55.
The exce~sive pr~ssllxe.s i~nedi.clte1y cause the relief valve~
65 to open to allow tlle hydraulic fluicl to f1.ow through the bypa.ss p.~s~ages 63 an~l 6~ and return to th~ reservoi.r 22. The ecce~-tric wil:1. collti.nue to reciprocate t-he pistons 50 and 51., anc~ a lclrrJe proporti.on of the hycl:Lau1ic flu.icl in -the pump ch~mhers 54 and 55 will ~e eY~pel1ed through the ~ypass passa~es.
As SOO~I ac~ the dispensiny nozz1e 13 is ar~ain r~opened, ~low is permittecl :Erom the pumpage chamber~ 32 of the diaphragm pl~nps and h~rlraul.ic fluid wil:i be dra~n into the purnp c,ha~ er~ 5~ ancl 55 throucJh the recill ports 56.2 ancl 57.3 so as to bring the pi~l:on pumps 40 and 4l bac]c to fully operating condition wi.thin a few strokes.
Similarly~ the cliaphragm pumps 28 ancl 29 will be operatinq at ~u11 capaci~y withi.n a E~w strokes aEter the r~openin~3 of the valved dispensi.n~ no~zle :L3.
In order to acco~nodate wide variance i.n the quantity of p~npincJ cles:irecl ancl the proper proportioni.n~
of ~he components, the variabl.e speed pulley 17 Oll the motor ~ha~t may be acljusl~ecl tv chancJe the speecl of the sha~t 20 ancl ctf the eccentri.c a3ld o~ the pis~:on pl.llllp5.
Durin~ operation of the di.aphrac3m pumps, the :inne~
and ollter perip}leri~s of ~.he c11aphragms 34 are clan~pecl and retainecl aCJclin~t unde,~.;ire~d Inoverllerlt throurJII the ef:~ec!ive operation of the beads 34.3 and 34.4. The beacls provide for extremely e:EEective sealing to prevent any migration of puMpage ox hydraulic fluid past the diaphragm.
The chemically re~.istant laMina 3~o2 of each o the diaph.rayn1s perrnits pumplng of an e~tremely wide range of materia1s wi-~h this proportioning pump. The lamina 34,2 is relatively thi.n compared to the neoprene ruhber lamina 34~l, but ls efficient to resist the effec~ of the pumpage liquids.

1 lB6073 Alt}loll(3h, in tl~e orrn .illustrélted, the eccentric provides a cal~lning periphe:~el1. surface 27a to transmit -the reciprocatirlc3 mot.ion to t-he piS-tOllS 50 a~d 51 which are al:igned ~:ith e~lCh othe.r. i:n t1.- e cylinder wall sl.eeves 56 and 57 whi.ch are also alicJned with ~ach other, it is readl:l.y under!>-..andable -that e,ach o-~ Ihe piston.s may be, in an alternate form, connected by a piston roc1 directly to the eccent:ric of the drive shaEt.
Fur~hermore~ it should be reco~nlzed t}lat although the ~orm of the inve~n-tion illustrated in Fi.~Jures 1. 4 has only one acljustable piston pump 40, wherei.n l.he sylinder wa11 sleeve 56 is longi.tudinally adjustable, in F.igure 5, the pump lOol incorporates two separate variable piston pumps 40.1 an~ ~0.?., both o~ which are identical with the lS plston pump 40 illustrated in Figures 1 - 3. Each of the variabl~ pi.ston pumps 40.1 and 40.2 operates a cor.responding diaphrac3m p~lp 28.1 a.~d 2Y,~2, ea~h oE whi.ch i.5 identical -to -the diapllr~Jtrl pump 28 ill.ustrated in Fiyures :L - 4 for pumping the culllporlents of the mixtur. In Fi.cj~re 5 the motor lG.l al50 ilaS ~ v,.lr.iable speed pul.:ley L7.:l. for varying the operat:illcJ speed o~ the pumps. ~ccordingly, a :ide variclti.on :in t;he~ proporti.orlin~ o:E ma.ter.ials beirll.3 p~?d c~clrJ 1~ O~te~ 'l t.:hrc~ Jl~ v~l.ryill{J ~ operal i.ol'l 0:~' the piston pWTIpS throucJIl their controls Ç0.1 anc1 60.2 in the manner previously described in collnectio~l with -the piston pump L1 O o~ Fi.~ures 1 - 4.
11l F.igure 6 the proportioni.ng pump 10 . 2 incorpo.r:ates ~h~ two pis~on pumps 40.1 and 40O2 o~ Fic3ure 5, and the diaphragm pun~ps 28.1 and 2R.2 thereof. In this Eorm, the sQurce o.~ reciprocatinc3 po~ler is provided by a double acting piston type air motor 75. It should be obvious that the alr motor 75 could also be used with the piston pumps 2~ and 2g OI ~iyure 1 and the correspondiny diaphragrn pumps 28 ancl 29.

~' 1 16~073 .l. ~;--T'.-le heads 50.1' o~ t~ns 50' of the pist~n pumps ~0.1 anc'l ao.2 are contlnuously urcJecl aqains-t the adjacerlt encls o~ the piston rod 76 by springs 52'. Piston 77 on rod 76 reciprocates in c,yli.nder 78, into which air under pxessure i.s supplied alld e.Y~h.lusted througll ports 79 ancl 80 in the cylincler wallr Ai.r .is supplled -~o and exhausted E~om th~ ports by a f'our-way valve 81 havincJ pilo-t operato~s 82 ~,nd 83 for shiftillcJ the ~alve~ Piston poS:ition sensing valves U4, 85 contro.l application o:E pressurized air to the pilot operators ~2, 83 so as to synchronlze the operati.on of' the four way valve 81. with the reciprocation of pist.on 77 and rod 76.
Air moto.r 75 may be operated to reciprocclte pistons 50' at the same rate ~nd with the s,~le effect as in the other forms of the invention.
Hyclraulic flui.d reservoirs 22.1 are provided in -the air ~otor housincJ ~la so as -to irnmerse -the pistolls 50 7 ~
spri.ngs 52' ancl the cylinder slee~es :f-'or supp].ying hydraulic Eluid int-o the pump chambers as herein described in connection wi-th Fi.gures 1 ~ ~. The reservoirs may be in-~,erconnected with I~assacJeways or conc1u.its if desi.red.
In certain ins~.ances, it may be desi.rable to reduce the capacity of one of the pis~.on pumps by ut:i.lizi.ng a piston of smaller diamet0r, and a cylinder slee~e of corresp~nd,i.ng sizeO In order to compensate or the varyinc3 loadin~ at the al.r rno-tor, the ai:r p:iston and the cyli.nder wall th~refor may both be stepped so as to have effectively different piston surface areas against which the pressuri~ed air acts.
In another form of the inven-tion, the pressure relief valves 65 may be entirely confined in a removable cartridge ox cap~,ule r SO aS to facilitate effectively eliminat~ J the pressure relief valve from the h~dra.ulic circui-t durincJ prlmi.ng, and wi.thout los:ing a pre-established settin~ of the relief valve~

~ ~66~3 -17~-It w.ill be seen tll~t: tile inverlt3.0n provides a two-component prOpOrtiOninCJ an~ t.andem di.apilracJm pul~p wherein the cylinder wall of one of the piston pumps ma~
he lon~i.tudinally adjusted to chancJe the pumpin~ stroke o -~he piston pump and there~y va.ry the qualltity oE
p~npage Erom the associated diaphrac~n pump~ The pump may be operated as a single pump without requiring the use of the t~o components, but ;.n mo.s~ instances two components will bP consistently pumped at the desired relative rates lQ to each other.

Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXLCUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A diaphragm type hydraulic pump, comprising a housing defining a reservoir for hydraulic fluid, a diaphragm pump having a pumpage chamber and a hydraulic fluid chamber separated by a diaphragm, the housing having supply duct means connected with the hydraulic fluid chamber, the housing also having cylinder means defining a hydraulic fluid pumping chamber in communication with the supply duct means, a piston in the pumping chamber, means cyclically reciprocating the piston in the pumping chamber, the cylinder means including cylinder wall means having an inner side facing into the pumping chamber and an outer side facing into the reservoir, the wall means having an open fluid port therethrough interconnecting the adjoining reservoir and pumping chamber and alternately transferring fluid to and from the reservoir, the cylinder wall means being adjustably movable in the direction of piston movement for relocating the port therein, a control connected with a threaded stem on the cylinder wall means and threaded into the housing and extending to the exterior of the housing for moving the cylinder wall means in the housing, and the threads between the housing and the control having a smaller pitch than the threads between the stem and the control.

2. The pump according to claim 1 and a second cylinder means with a second pumping chamber and a second piston, the second cylinder means also including a second wall means with an inner side facing into the pumping chamber and an outer side facing into the reservoir, the second wall means also having a fluid transfer port communicating between the pumping chamber and the reservoir.

3. The pump according to claim 2 and said second wall means being stationary with respect to the housing.

4. The pump according to claim 1 and the diaphragm having multiple laminations and including a neoprene rubber lamination adjacent the hydraulic fluid chamber, and a lamina of substantially chemically inert plastic facing the pumpage chamber.

5. The pump according to claim 1 and a rotary eccentric operating said means cyclically reciprocating the piston.

6. The pump according to claim 1 and a reciprocating air motor operating said means cyclically reciprocating the piston.