CA1183403A - Two-component metering pump - Google Patents

Abstract

Abstract of the Disclosure A proportioning 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

~~
rrhis application is a divisional of application Serial Number 354,490 EilaA June 20, 1980.
This invention relates to variable diaphragm type me-teriny pumps, and more particularly, to an adjustable pump which is well adaptecl f.or accurately and adjustably supplying metered quantities of a two-component product.

Back~round o.~ t:he Invention One common usa~e of mete;ring pumps is in the measuring o~ componen~s of multi-component products, such as paints, resins, and .Eloor coveringfi, ancl also .in adding small quantities of concantrate to w~ter as i.n .~ertil:izing ancl spraylng herbicides onto crop fields.
Ik is readily apparent that with such w.idely di.fferen~ usages, numexous requirements are encountered as to make very substantial demands upon the capability o~ the pump.
Although a two-component metering pump has been known previously, inherent construction features cl~arly limit the use~ulness in certain situations. Metering 20 capability has been provided by mechanically limiting the return stroke of the pistonO See U.S. Patent 3,612,727 In limiting the return stroke of the piston, the piston encounters a mechanical stop which suddenly absorbs the inertia of the piston, any assemblies connected with it, and the diaphragm-operatin~ hyd.raulic fluid or oil.
The revolving cam will initially lift off the stopped piston and then impact the pis~on again to suddenly start it into motion. Depending upon the shape of the cam and the time in each cy~le at which the cam reengages the piston, the repeated impact of the cam against the pi~ton and the repeated impact of the piston against the stop can create substantial vibration in ~he pump.
Other single component diaphragm type metering pumps have us~d other types of mechanisms ~or varying the pumping rat:e. For ins~ance, one pump has a port in the ~ 3-piston for suddenly releasing pressure in the cyllnder at the end of the pressure stroke, as the pis ton port pa~3e~ by the end of a stationary and adjustable rod, see U.S. Patent 3,285,182. Another pump varie~ the length of stroke o the piston by varying the eccentricity of the driver or the piston, see U~S. Patent 3,3'74,750. Such varyirlg of eccentricity involves compllcat.ed mechanisms; and r~lylng upon rel.ie~ o developed pre~sure at the end o~ the pressur~
stroke requires a rather compll.cated mechanism and the developing of vacuum pressures on the return ~troke which cause related complicatin~ problems.

Still other diaphragm type pumps show the bas.ic separation between the hydraulic fluid pumped by the reciprocating piston and the other liquid pumped by the diaphragm. Excess pressure under certain cir~umstances is rel ieved in various ways in these pumps and o aourse refilling of the cylinder after such relief i3 necessary~
5ee V.~. P~tents 2,578,746; 3,075,468; 3,254,845; and 3,680~9~1.

Brief Summar~of the Invention An object of the invention is to provide an improved two-component diaphragm pump to simply and effectively var~, over a wide range, the quantities of components pumped.

3~3 ~, The variable diaphragm pump has as an adjustment control and proportion-varying apparatus facilitating extremely accurate adjustments of the cluantities pumped, these adjustments be.ing accurat:ely repeatable.

In a preferred embodi.ment of the .invention the two-component proportioning diclphragm pump provides for relie of the pressure oE the pumping hydraulic fluid when flow o the pumpage is suddenly stopped, and prevents relleE
of any oE the pressure oE the hydraulic 1uld during normal operatlon and flow of the pumpage to the dispensing noæzle.

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 adjufitable sleeve Eorming the cylindrical wall of one of the piston pump~ in order to obtain the desired proportioning at the diaphragm pumps.

In another preerred embodiment of the 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 the piston extend~ into the interior thereof.

Another feature of a preferred embodiment of the present invention is the provision of a variable speed characteris~ic in the two-component proportioning pump for ~ 5--controlling the quantity o pumplng by both of the diaphragm pumps and with control apparat:us for changing the relative pumping capabilities of the two diaphragm pumps to ob~a.in correct proportioning of the pumped liquid.

Another embodiment of the invention has a double thread adjusting arrangement 011 an adjustable ~leeve forming the cylinder of a piston pump operating the diaphragm pump.

In the two-component proportioning pump embodlment of this invention utilizing tandem diaphragm pumps, the diaphragms are oE a sandwich construction of 8una-N rubber at the oil side of the diaphragm and Teflor~ at the pumping side of the diaphragm to resist deteriorating e~fects of liquids being pumped and the sandwiched diaphragrn has annular inner and outer æeallng beads confined ln grooves in the housing and the piston~operated ~tem attachment. The diaphragm pumps, can be driven by elther a rotary eccentric or by another fast acting reciprocating drive; such as a 20 piston type pneumatic motor.

A principal advantage obtained ~y th~ present invPntion is the accurate metering of a quantity of liquid being pumped and permitting the quantity o liquid to be varied consi.derably and without allowing any undesired vibrations l:o be set up in the pumping assemblyt regardless o the pressure and speed involve~.

* Trade Mark 3~3 llr~el D~ri~ti~
Figure 1 is a diagrammatic plan view illustrating the invention .
Figure 2 is a longitudina:L section view taken on an up-right plane as indicated approximatel~ at 2-2 .in Figure 3.
Figure 3 is a longitudinal section view taken approxi-mately at 3-3 in Figu~e 2.
Figure ~, which appears on the first sheet o~ drawings/
is a~ enla.rged detail section view taken approximately at 4-4 in Figure 3.
Fiqure 5, which appears on the ~irst sheet of drawi~gs, is a diagrammatic plan view showing a modified form of the invention.
Figure 6 is a~ elevation view, partly in section, of a modified form of proportioning pump.

~e~ai e~_9~ecl~icatio~

The variable two-component pump is indicated in ge~exal by numeral 10 and is illustrated in Figure 1 to ~e : typically u~ed to supply the pumpage to a mixer 11 from which the mixed components are conveyed by a long hose 12 to an airless sprayer 13. It should be recogniz~d that supplemental equipment may be employed between the pump 10 and ~he mixer 11, for accomplishing such functions as heating and filtering the pumpage. In ~ne typical usage, resin ~s supplied from one source 14, and catalyst is supplied from another source tank 15.
A motor 16 provides a rotary source of power for the pump 10 and is connected through a va~iable speed pu].ley 17, belt 18, and pulley 19 o the input shaft ~0 of the pump~

In the form of pump illustrated in Figures 2 and 3, the pump 10 has a housing ~1 which de~ines a c~ntr~l chamber 22 de~ining a xeservoir for hydraulic fluid.
The shaft 20 is mounted on bearinys 23 and 24, ancl d~ii.ne~r, an eccentric 25 which includes an ~ccentric portion 26 of the shaft 20 which is emhxaced by a ball be~riny 27, the outer annular peripheral su:race 27a o~ whJ.ch ~yrates as an eccentric around the rotation axis o~ the ~haf~ 20.
The pump 10 include,~ a pair o diaphragm p~p~ 2 and 29, and a pair of piston pumps 40 and ~1.
The t~o diaphra~m pump~ ~8 and 29 are essentially idenkical to each other, and identical re~er~nce numerals axe used ~or both. The housing 21 has recesses 21.1 and 210 2 receiving the frame blocks 30 of ~he diaphra~n pumps.
End covexs 31 are affixed to the housing 21 as by cap screws for capturing and clamping the rame blocks 30 in ~tationary position.
The diaphragm pumps 28 and 29 have pumpage chambers 32 and hydraulic ~.uid pumping chambers 33 on opposite sides of diaphragms 34.
A diaphragm stem 35 i5 ~ttached by clamping to the center o~ the annular diaphragm 34, and extends into the supply duct 36 in rame ~lock 30 which communicates with the hydraulic fluid chamber 33. A compression spring 37 ~5 has one end hearing against a ~houlder in the rame block 30, and the other end bearing again~t a washer 38 anchored to the free end of the diaphragm stem 35 as by a retaining screw~ The diaphragm stem 35 is guided by a stationary bearing sleeve 35.1 in the ~upply duct 36 and spaced ~rom the frame block 30 by a spider-like mounting.
The diaphxagms 34 are of annular and laminar CQnStruction~ wi~h a lamina 3401 of neoprene rubber~
facing ~h~ hydraulic fluid chamber 33, and a 12~ina 34.~
of a ~ubst:antially inert plastic such as a plastic known by its trademark M~LARf or of anb~her plastic known by its 33~3 trademark TEFLON, more speci.fically polyfluorotetra~
ethylene.
The diaphragms 34 have annular beads 34.3 at their inner peripheries, and annular beads 34.4 at their outer periphexies.
The outer heads 34.~ o~ the diaphragms ~it into annul~r grooves 30.1 in the~ Eram~ blocks 30; ~nd the inner heads 34.3 ~it into annular ~rooves 35.2 ~oxmed in the clamping head 35.3 on the encl o~ the diaphragm ~tem 3.5.
Th~ inner peLiphery of th~ diaphragm 34 ls clamped against the head 35.3 by a clclmping disc 3g retained onto the end oE the diaphra~m stem by a scr~w 39.1.
q'lle pumpage chambers 32 of ~he diaphragm p~nps 28 and 29 are connected through fit~ings 42 and 43 which are respectively provided with inflow and outflow check valv~s 44 and 45 through which the pumpage is directed in~o and out of the pumpage chambers 32. The fittings 42 are connected to supply flow lines 46 and 47 from the two sources of materials to be mixed; and the discharge fittings 43 are connected to the discharse hoses 48 and 49 which ~upply the components to the mixer 11.
The diaphragm pumps 28 and 29 are respectively operated by hydraulic fluid pumped from the piston pumps 40 and 41. The piston pump~ 40 and 41 have reciprocating pistons 50 and 51 which have bearing heads 50.1 and 51.1 which bear against the peripheral surface ~7a of the eccentric. Coil springs 52 and S3 bear at one end against a shoulder of the housing 21',and bear against the heads 50.1 and 51.1, respectively, of pistons 50 and 51 to continually urge the pistons against the peripheral surface of the ecceIItric.
The cylinders 54 and S5 in which the pistons 50 and 51 reci~rocat~ are defined by cylinder wall sleeves 56 and 57~ respectively. Cylinder wall 57 is stationary in the housing 21'and is clamped by the adjacent frame 3~
9~

block 30 so that a shoulder 57.1 abuts agains~ an adjoining ~houlder in the housing 21'. A significant length of the inner end of the cylinder wall sleeve 57 extends i.nto the hydra~lic fluid reservol.r 22 which surround~; ~he outer periphery 57.2 of the inner por~ion oE the cylinder wall sleeve 57. ~ pair of ports 57~3 extend throu~h the cylinder ~all sleeve 57 arld com~unicate at their inner ~nds w.ith the pump ch~mber Ol c~linder 55, and at their outer end3 with the re~ervoir 22.
It wil]. he no-ted tha~ the ~pr.ing 53 closely embraces the outer periphery o~ the cylind~r wall sleeve 57.
The inner end 56.1 of the cylinder wall sleeve 56 also extends a signif.icant distance into the reservoir 22, lS and ports 56.2 through the cylinder wall sleeve 56 provide communication between the pumping chamber or cylinder 54 and the reservoir 22 at the outer periphery of the slee~
56. Sleeve 56 is snu~ly mounted in a bore 21.1 of the housing and is longitudianlly slidable therein. The sleeve 56 has a closed head portion 56.3 which has a lon~itudinal keyway or groove 56.4 therein. A keying pin 58 is threaded in the housing 21 and extend~, into the keyway $6.4 for guiding the cylinder wall 56 in its longitudinal movemen~ without permitting any rotation of the sleeve.
The cylinder wall sleeve 56 is provided with a stem 5~.5 having threads 56.6 on its outer periphery~
The stem 56.5 is threaded into a rotary control in the foxm of a sleeve 59 having a knurled head 60 affixed thereon. The ro~ary control 59 has a ~hreaded exterior surface 59O1 which is threaded into a boss 61 formed integrally o~ the housin~ 21.
The threads at both the inner periphery and the outer periphery of the annular rotary control 5~ are both righthand threads, but they have a diffçrent pitch.

f ~ f~ ~ r#

At the outer periphery of the rotary control 59, the th.reads by which the rotary control S9 is connected ~o ~he boss 61 o the housing has an 18 pitch in the form .illustrated. The threads at the inner p~ri.phery o~ the rotary control and Oll the stem 56~5 have a 24 pitch.
Accordin~ly, turning -the rotary control 59 and 60 throucJh a significant arc of rotation, will produce ~nly a very limited endwise movement of the stem 56~5 and o~ th~
cylinder wall sleeve 56.
The cylinder wall sleeve 56 has a plurality o~
large flow ports 62 there~hrough for open commun~cation with the duct 36 which communicates with the hydraulic ~luid chamber 33 of the adjacent diaphragm pump 28.
Pressure xelie~ or bypass passages 63 and 64 are provided in the housing 21 to allow hydraulic fluld ~o return from the pump chambers 54 and 55 to the reservoir 22 under certain conditions, such as when the spray nozzle 13 is suddenly closed so as to pre~ent any pumpage from moving out of ~he pumpage chambers 32 of the diaphragm pumps. Pressure relie~ valves 6S are provided in the bypass passages 63 and 64 and are subst~ntially identical with each other. Each of the pressur0 relief valves has a valve element 66 urged by a spring 67 agains~ the valve seat 68 so as to keep the pressuxe relie~ valve 65 closed until pressure in the ad~acent pump chamber exceeds a predetermined minimum. The tension on the ~pring 67 is maintained and adjusted by an anchor 6B threaded into a mounking plug 69 which is threadably connect~d to the boss 70 o~ the housing 21.
Communication is provided from the pump chamber 54 in~o the pressure relief valv2 65 in the passage 63 through an annular manifold groove 71 in housing 21 and extending entirely around the outer periphery o~ cyli~der wall sleeve 56 adjacent the ports 62. The manifold groove 71 also co~municates with the duct 36 through which hydraulic fluid is supplied to the hydrawlic fluid chamber 33 of the diaphragm pump 28.
Th~ cylincler wall sleeve 57 has similar ports 62.1 - wh.ich provide Elow conununication into an annular mani~ol.d groove 71.1 to allow the hydrau].it fluid to enter the bypass passage and pa5s by the relie:~ val.ve 6S in the ~vent of ~xcessive pre~sllLe5.
In operatiol-, the mol:or 1~ is operated and the variable ~pc~ pu].le.y 17 .is adju~t~d a5 to produc~ rota~ion 1.0 oE tho sha~ 20 at a speed within the range o~ approxi-mately 200 to 1200 rpm. The ~uantity of pumpage from the two diaphra~m pumps 28 and 29 may be varied ovex a wide rang~ by chan~ing the speed of the drive shaft 20.
Changin~ the speed will change the pumping rate of the two diaphragm pumps in substantially direct relation to the ~peed of the driv~ sha~t. In addition~ the pUmpinCJ rate o~ the diaphragm pump 28 may be changed by adjusting the hand control 60 as to produce longitudinal relocation oE
the cylinder wall sleeve 56 and of the port 55.2~
~s the shaft ~0 revolvest the eccentric produces reciprocation of the pistons 50 and Sl. The pistons are almost entirely confined in the cantiliver end portions of the cylinder wall slceves 56 and 57 which project into the reservoir 22.
~s ~he piston 50 progresses from the position illustrated in Figures ~ and 3 in an outward direction along the cylinder wall sleeve 56~ the leading face of the piston 50 will initially move across and then close the ports 56.2 in sleeve S6~ Until the ports 56.~ are entirely closed, the pumping s~roke of the piston pump 40 does not commence. At ~he instant ~he piston 50 closPs the ports 56.2, pumping action commences, and the hydraulic fluid commences to ~low through the ports 62 and duct 36 into the hydraulic fluid chamber 33 of diaphragm pump 2~.
As the hydraulic fluid in chamber 33 moves the diaphragm 3~3 34, pumping o~ the liquid in the pumpage chamber 32 comm~nces, and continues unt:il tlle eccentric completes the outward movement o~ the piston 50. As the piston 50 stops and then starts return:in~ inwardly under the influence o~ spring 52, the spri.ng 37 of diaphra~m pump 2 draws the diaphragm toward its rest position; and s.imultaneously, the pumpage ch~mber 3~ is again re~illed with the li~u~d from the soUrce 15.
Simultan~ously as the eccentric is dr.iving the piston 50 outwardly, and subæe~u~ntly a~ the ~pring 52 return~ the piston 50 to the pOSitiOII shown in Figures 2 and 3, ~he other piston Sl is also being moved. Xnitially, ~rom the pos.ition illus tra ted in Figures 2 and 3 ~ the piston is moved under the influence of spring 53 in an inward direction as the eccentric revolves to allow such inward movement. The movement of piston 51 permits the spxing 37 to draw the diaphragm 34 ~oward the hydraulic fluid chamber 33; and simultaneously the pumpa~e chamber 32 i8 being enlarged to draw liquid from the source 14 for the next pumping stroke. During the normal operation of the pump while the no~zle 33 is open so that both o~
the diaphragm pumps 28 and 29 are fully operating, there will be no flow whatever through the bypass passages 63 and 64, and the valves 65 remain entirely closed.
25 In this circwmstance, there is es~entially no flow through the ports 57.3 of cylinder wall sleeY~ 57 and ports ~6.2 of cylinder wall sleeve 56, because there has been no loss of hydraulic fluid from the pump chambers 54, 5S during the normal operation of the piston pumps. If there is some small loss of hydraulic fluid due to seepage along the piston or o~herwise, the hydraulic fluid in ~he pump _, chamber~ 54, 55 will be replenished during each stroke of the pistons through the ports 56.2 and 57.3.
Tlle advantagesof extending the cylinder wall 35 sleeves 56 and 57 well into the xeservoir 22 are numerous.

3'.~

The re~ill passages or ports 56.2 and 57.3 are extremely shor-t, equaling the thickness of the cylinder wall sleeves 56 and 57. There is no need for purposes of the refill to utilize long and complicated passages in the housing 21. Construc-tion o~ the piston pumps 40 and 41 ls simple ~)y virtue of ~he removable cylinder wall slee~es so that in -the e~ent any m~intenance or adjustment dS to cylirld~r and piston slze is desired, the cyli.nder wall sleeves can be readily replaced. ~h~ proportions o~ the matexials be.ing pumped may be very accurately controlled by adjustiny the rotary control 59, 60. ~rhe slightly di~erent pitch on the threacls a~ 56~6 and 59.1 allows the rotary control 60 to be revolved through a significant arc for a small amount of longitudinal movement of the sleeve. Because of the care~ul control of the longi~udinal movement of sleeve 56, tha rotary control 59, 60 can allow the setting of the sleeve to be repeated during se~uential pumping operations. As illustrated in Figure 2, a scale may be provided around the periphery o the hand wheel 60 and on the boss 61 to produce a vernier scale~
Some materials being pumped ma~ var~ ~rom batch to batch or with the tempexature condi~ions and the adjustmen~ of cylinder wall sleeve 56 can minutely afect the quantit~ of material pumped by the diaphragm pump 28, Simply changing the longitudinal position of th~
cylinder wall .sleeve 56 causes the ports 56.2 to assume a new position so as to cause the piston 50 to change the phasing of closing of the port 56.2, whereupon to actuall~
change the amount of hydraulic fluid moved in ~nd out o the hydraulic fluid chamber 33 o the diaphragm pump.
In the event ~hat the dispensing nozzle 13 is suddenly closed to stop ~he flow of the pumpage from the two diaphra~m pumps 28 and 29, the hydrau.l.ic fluid from pump chambers 54 and 55 is no longer capable o moving the diaphragms 34, ~nd accordingly, excessive pressures 3~
~ ..
~1'1--are immecl.iately created ln the pump chambers 54 and 55.
The excessive pressures immediately cause the relief valves 65 to open to allow the hyclraulic flu.id to flow through the bypass passages 63 and 64 ancl xeturn to the reservoir 22. The eccentric ~Jill continue to reciprocate the pistons 50 and Sl, ~nd a l.arge proportion of the hydranlic fluid in the pump chambers 54 and 55 will ~e expelled through the bypass passages.
As soon a5 the d.ispensiny no~zle 13 is agairl reopened, flow .is permitted from the pumpage chclmbers 32 o~ the diaphragm pumps ~nd hydraulic fluid will be drawn :into the pump chamber-; 5~ and 55 throu~h the refill ports 56.2 and S7.3 so as to bring the piston pumps 40 and 41 back to fully operatin~ cond.i.tion within a few strokes.
Similarly, the diaphragm pumps 28 and 29 will be operating at full capacity ~ithin a few strokes after the reopening of ~he val~ed dispensing nozzle 13.
In order to accommodate wide variance in the quantity of pumping desired and the proper proportioning of the components, the variable speed pulley 17 on the motor shaft may be adjusted to change the speed of the shaft 20 and of the eccentric and of the plston pump5.
During operation of the diaphragm pumps, the inner and outer peripheries of the diaphragms 34 are clamped and retained against undesired movement through the ef~ective operation of the beads 34.3 and 34.4. The beads provide for extremely e~fective sealing to prevent any migration of pumpage or hydraulic fluid past the diaphragm.
The chemically resistant lamina 34.2 of each of the diaphragms permits pumping of an extremely wide range of materials with this proportioning pump. ~he lamina 34.2 is relatively thin compared to the neoprene rubber lamina 34.1, but is efficient to resist the effect of the pumpage liquids.

3~

Although, i.n the form ilLustrated, the eccentric provi.des a camming peripl~eral surface 27a to transmit the reciprocating moti.on to the piStOIIS 50 and 51 which are aligned w.ith each other in th~ cylinder wall sleeves 56 and 57 whicll are also ali.gned with each other, it is readily understandahle that each oE tlle pistons may be, in an alternate ~o:rm, connected by a piston rod directly to the eccentric of the drive shaft.
Furthermore, it shouJ.cl be .recocJnized that although the ~orm o~ the inven tiOII ill~lst:rated in Figures 1 ~ 4 has ol)ly o~e adjustable piston pump 40, wilerein the cylinc.ler ~all sleeve S6 is longitudinally adjustable, in Figure S, the pump 10.1 incorporates two separate variable piston pumps 40.1 and 40.2, both of which are identical with the piston pump 40 illustrated in Figures 1 - 3. Each of the variable piston pumps 40.1 and 40.2 operates a corresponding diaphra~m pump 28.1 and 28.2, each of which is idelltical to the diaphragm pump 28 illustrated in Figures 1 - 4 fox pumping the components of the mixture. In Figure 5 the motor 16.1 also has a variable speed pulley 17.1 for varying the operating speed of the pumps. Accordingly, a wide variation in the proportioning of materials being pumped can be obtained through varying the operation of the piston pumps through their controls 60.1 and 60.2 in the manner previously described in connection with the piston pump 40 of Figures 1 - 4.
In Fi~ure 6 the proportioning pump 10.2 incorporates the two piston pumps 40.1 and 40.2 of Fiyure 5, and the diaphragm pumps 28.1 and 28.2 thereof. ~n this form, the source o~ reciprocating power is pro~ided by a double acting pis~on ~ype air motor 75. It should be obvious that the air mo~or 75 could also be used with the piston pumps 28 and 29 of Figuxe 1 and the corresponding diaphragm pumps 28 and 29.

3 i~ ~ ~
~:L6 The heads 50.1' o~ p:istons 50' of the piston pumps 40~1 an~ ~0.2 are continuously urged against the adjacent ends of the piston rod 76 ~-y springs 52'. Pi.ston 77 on rod 76 reciprocates i.n cylindcr 78, into which air und~r 5 pressure is supplied ~nd exhausted throucJIl ports 79 and 80 in the cylinder wall. Air is supplied to and exhaustecl ~rom the ports ~y a four-way valve 81 hav.incJ pilot operators 8 and 83 for shiftincJ the va.lve. Piskon pos.ition serlsl.ng va~ves ~, 85 control application of pressurized ai.r to the pilot operators 82, ~3 so a~ to synchronize thc opcra-tion o:~ the eour way v~llve 81 with the reci.procation o piston 77 and rod 76.
Air motor 75 may be ope~ated to reciprocate pistons 50' at the same rate an~ with the same effect as .in the other orms of the invention.
Hydraulic fluid reservoirs 22.1 are provided in the air motor housing 21a so as to immerse the pistons 50', springs 52' and the cylin~er sleeves for supplying hydraulic fluid into the pump chambers as herein descxibed in connection with Figures 1 - 4. The resexvoirs may be interconnected with passac3eways or conduits i~ desired.
In certain instances, it may be desirable ~o reduce tha capacity of one of the p.iston pumps by utilizing a piston of smaller diameter, and a cylinder sleeve o~
corresponding size~ In order to compensate for the varying loading at the air motor, the air piston and the cylinder wall therefor may both be stepped so as to have effectively different piston surface areas against which the pressurized air acts.
In another form of the invention, the pxessure relief valves 65 may be entirely confined iII a removable cartridge or capsule, .so as to facilitate effec~ively eliminatlng the pressure relief valve from the hydraulic circuit durincJ primi.ng, and witl-out losing a pre-established settillg of the relief valve.

~17~

It will be seen khat t:he invention provides a two-component proportioning an~ tandem diaphragm pl~p ~herein the cylinder wall of on~ of the piston pumps may be loncJitudinally adjustec1 to chanJe the pumpi.ng st.rok~
S o.~ the piston pump ancl there~y vary the quanti~y o~
purnpage from the associate~ cli.aphratJm pumE~. The pump may be op~ratecl as a sin~l.e pump without l~e~1u:iring th~ u~3e o~
the two components, but in mo~ instances two cornponents will be co~sic;~ently pumped at the desire~1 lelative rates to each o-ther.

Claims

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

1. In a multiple-pump system for metering multiple components for combined and controlled dispensing thereof of the type having a common pump drive, at least one diaphragm pump including a pumpage chamber and a hydraulic fluid chamber separated by a diaphragm, pump means operating said diaphragm pump and including a cylinder and piston defining a pumping chamber in communication with said hydraulic fluid chamber, said piston being reciprocated within said cylinder by said drive, and a reservoir for hydraulic fluid, the improvement for proportioning said components for dispensing wherein said cylinder comprises cylinder wall sleeve means extending into said reservoir and being selectively movable in the directions of reciprocation of said piston, port means extending through said cylinder wall sleeve means between said pumping chamber and reservoir, the piston reciprocating across the port means to alternately open and close the port means during each pumping cycle, means selectively moving and retaining said cylinder wall sleeve means for altering the pumping stroke of said piston and normally closed pressure relief means interconnecting said reservoir and pumping chamber for opening in response to a pressure increase resulting from discontinued dispensing.