US2797846A - Pump control system - Google Patents

Description

July 2, 1957 E. E. REED PUMP CONTROL SYSTEM 2 Sheets-Sheet l Filed Aug. v2:3, 1953 v July 2, 1957 E. E. REED PUMP coN'rRorLafsYsTEn/I 2 sheets-sheet 2 Filed Aug. 28, 1953 Reed ATTORNEYS;

TUMP CoNTRoL" SYSTEM QEdwinl Reed,l Bartlesvillekla., Vassigner to" Phillips V'Petroleum Company, a corporation of Delaware Application August 28, 1953, Serial'No. 377,170

- '10 Claims '2(Cl. 222-6S) This 'invention 4relates to' pump` control systemsf in which 'thenumber 'of pumps being employed is varied 't `with the load.y In oneaspect it rel'atestto a'pump control fsystem having a pluralityV of '-pumps 1in'l whichthere is means to' select the order 2in' Awhich the pumps willf'be cal-lede upon for service as the load'onthe system increases. f Inanother aspect it relates to a fluid dispensing service -stati'on'system for dispensing lluids fron-rawstorage-- tank to anuinber-'of-dispensing stations.

`One object .of'tthis invention is to provide a pumping systemy withy a plurality of uid pumpsy 'with' means responsive-to the` flow of .they combined discharge-ofthe pumps toregulate the number of pumps being employed. t Another object is to` provide 'a process of pinnpingby a pluralityy of pumps comprising selecting the :order in which the pumps are to be'employed and employing more pumps `when Vincrease in flow indicates ithis'fis desirable.

-Another object isto provide a simplebuteective control for a stand-by pump' in service station'operat tions.

-A further-object isto provide a completely integrated uid'- dspensingfservice station system suitable 4for use :in large service stations-having aplurality oflfluiddispensing lines-connected to each storagetank, especially such large gasoline service stations asare becoming common on turnpikes, such'asthe turnpikes in Pennsylvania, New Iersey,'New York, Oklahoma and other states.

Numerous -other objectsand advantageslwill be apparent to those skilled in the-artupon reading'the accompanying specifications, claims and drawings.

In the drawings: Figure l is an elevational View, with -parts in section land the electrical wiring system shown in conventional symbols, of a uidfdispensing system embodying'thepresent invention suitable for use in dispensing liquid'wgasoline or other fluid fuels to motor vehicles.

Figure 2 is a similar view-of a modified systerniof the same general typefas Figure 1.

Figure 3 is anielevational cross-sectional `viewwoia -third modification of adilterential pressure" responsive means which may bev substituted for either ofthezlcorrespondinglmeans inF-igures 1 or 2.

Figure 4 is a modified Wiring diagram fortuse'f'in VFigure l.

-In Figure l is shown a uid dispensing service'st'ation system, although obviously the'system is useful in other applications. However, for the purpose of illustrating this invention, a liquid fuel dispensing system suitable for dispensing such fuel to automobiles is shown in Figure 1.

In Figure l, a storage tank 6 is shown containing liquid fuel 7 which has vapor (or air) 8 in the upperpartof the tank. The storage tank 6 is buried in the earth 9 and a portion of theearth is preferably-covered with a concrete slab (or slabs) 11 so that automobiles being serviced will not mire down in themud when it rains.

' Tank 6 is provided with aiiilling line 12 .having a-suitable pivot 13 for connection of a pivot cover ,cap14.

United States PatenttliFice 2,797,846 -Patented July 2, 1957 3 1-The'\c'ap\14 is pivoted counter-clockwise about pivot-"13 Ywhen the gasoline tankf truck' Iilling hose (nctshown) is insertedin'pipe 12 to'll tank 6 with gasoline,or other f liquids For convenience, the upper portion ofthe lling line"12-is Vlocfat'edin a recess 16 in slab 11 which may Hbe closed by a'-ush trap door 17 pivoted at 18 to door frame 19. While-not absolutely essential, it is preferable to-alsovhave avent `4line 21v to vent the vapor phase 8 I to theatmosphere and this vent line 21 maybe as long asldesiredf tofcarry" the vapors to a safev place, and the open endoffvent line 21 may be covered by a suitable rain cap 22.

A plurality of pumps 23 and 24 are provided, and

"lthese'lmay-'be centrifugal pumps as shown in Figure 1,

-oriothe'r types of pumps such as positive piston lpumps or t '-gearflpumpsas indicated in Figure 2. Each pump has an inlet'line-26fand"27 respectively, and theseinlet lines "'e'xtendfdown near the bottom of tank 6, although it is customary' to, have them stop short of the bottom of tank 6'inorder toy provide a suitable space for the collection 1 of"water,1foreign material and sediment; withoutl the same 'being drawninto the inlet'lines v26 and "27. Each pump *has a motori `V28- or` 29 respectively driving 'the #same throughfany suitable drive connectionindicated by v dottedlines31 and 32.` respectively, and while obviously other motors, gas, steam or compressedy air turbines, Ien- Aginesyor other prime-movers (not'shown) could be emt ployed,y itl is'ip'referredlfto 'provide electrical motors `2S and 29as-rshown. When 'pumps'23 and -24 are centrifugal pumps, asy shown, it is necessaryl tohave Icheck `valves `tltin` lines"26 and 27 to'prevent return ow to the tank through an idle pump whenthe other pump is pumping. "With some positive `Ipumps 143, 144 and-146, no checkyalve is necessary, or the'check -valve (not shown) is part of the pumpfPumps 23 and 24 discharge through outlet yconduits Y33 and 34.respectivelytinto a common manifold-36 whichiin` turn discharges into a discharge line 37 to which are connected dispensing lines 38, `39 and 41. Said'dischargeline 37 is provided with a flow restrictor 42 of any type, such as thediaphragm orifice -Y plate shown, 'and this restrictor need not cause anysubstantial restriction' ofi'lowaslong as there is enough lrestriction Ato produce a sutlicientditferent pressure-at f point-43`above:that atV point44 to operate a differential pressurerespon'sive electrical connecting means generally designated. as '46.

measuring means which can be used, `as any such` suit- Aable means may be employed as shown by corresponding v A simpler differentialpressure responsive electrical connecting means is shown at 46 in Figure 1, and this means is, operative and useful in the operationof this invention. However, it-is-notthe only type-of differential pressure parts 156 in Figure 2 and 196 in Figure 3, vwhich also are suitable for use inFigure l. Furthermore, it is sometimes desirable to use more complicated devices which may operate between closer limits, and one such device suitable for use` as said means is the model 211 Mercoid differencein'pressure at points `43 and 44 in discharge line37.on;opposite side of said llow restrictor 42. Means i6-consists offan `M shaped `piece of pipe 47 at least a portion148 of'fwhich isx-made of electrically non-com '3 ducting material for the purpose of insulating electrode 49 from the remainder of the pipe, a portion of which is electrically connected to electric wire 51. While the system will work electrically with wire '1 connected to pipe 46 in such a manner that it is also grounded through pipe 37, it is preferable not to ground any electrical equipment through fuel pipes, and therefore a section of insulating pipe 50, of corresponding structure to pipe 48, is preferably provided in order to electrically isolate 51 from ground. In the central U shaped portion 52 of pipe 47 there is located an electrically conductive liquid 53, which may be mercury, for the purpose of completing the circuit between wires 49 and 51 through the walls of pipe 52, and mercury 53 when the mercury extends into non-conductive portion 43 far enough to contact wire 49.

A number of valves are shown merely because they are useful in emergencies, although they are not opened or closed during the normal operation of this system. During normal operation valve 54 remains closed as does valve 56 and valves 57, 58, 59, 61 and 62 remain open. The chief reason for valves 54 and 56 is that they can be used to establish communication with additional pipes (not shown) in order to connect with additional pumps (not shown) similar to pumps 23 Vand 24 and to additional dispensing lines (not shown) respectively similar to lines 38, 39 and'41, in case it is desired to enlarge the system, and of course valves 54 and S6 are useful if it is desired to clean out manifold 36 and pipe 37. Ordinary pipe caps (not shown) could be used in place of valves 54 and 56. Valves 57 and 58 have similar utility as in case of the complete breakdown of its respective pump one of these valves rnay be closed until the pump is repaired without causing a complete shut-down of the system. The chief utility of valves 59 and 61 is to permit the removal or repair of means 46 without completely shutting down the system. Valve 62 has no utility during the operation of the system, as obviously closing valve 62 would result in a complete shut-down of the system, so it remains open at all times, and is only useful to separate the system into parts when shut-down, for example so line 37 can be cleaned out without involving parts to the left of valve 62.

Each dispensing line 38, 39 and 41 leads to a separate dispensing station generally designated as 63, 64 and 65 separated from the other dispensing stations preferably by a distance greater than the length of the average automobile if one lane of automobiles is being serviced, or greater than one-half the length of one automobile if vehicles are being serviced in lanes on each side of the dispensing station, and obviously the dispensing stations can be arranged in several rows, or other groups to provide the most eicient arrangement. While only three stations, 63, 64 and 65 are shown, it is obvious that many more could be attached to discharge line 37, and the discharge line could branch after leaving point 44 in order to accommodate several rows of such dispensing stations. With more stations each station (not shown) would have a switch across wires 102 and 91 in parallel with switches 97 in stations 63, 64 and 65.

It will be noted that the dispensing stations selected for illustration in Figure l are objects which the public generally calls gas pumps but they are called dispensing stations herein because the actual pumps 23 and 24 are not located at the dispensing station. Each dispensing station, such as 63, may comprise a decorative housing 70 on the exterior of which may be placed advertising material 66 (such as the trademark of the iluid being dispensed).

The dispensing line 38 has a meter 67 disposed therein which is conventionally housed in housing 70 of the respective dispensing station 63 adapted to measure the amount of iluid passing through the same. The amount can be measured Vby volume, or by weight, by any suitable meter from the prior art which will meet the requirements of the law in the particular jurisdiction involved. Meter 67 drives indicator 68 as indicated by dotted line 69 and indicator 68 indicates the amount of uid passing through the respective dispensing line 38. This indication is preferable both in terms of amount on odometertype numbered disks 71 and as to price on similar disks 72, and while not necessary to the operation of the invention, it is commercially preferable to have means 75 to set disks 71 and 72 back to zero for each new customer along with another set of odometer disks which cannot be reset and read the total amount from the time the system was installed. Odometer disks 80 may be `concealed, or revealed to the customer as shown.

A portion 73 of the downstream end of each dispensing line is preferably made flexible, such as a ilexible hose made of any suitable material. At a point adjacent the open downstream end 74 of each dispensing line is a dispensing shut-olf valve 76 which may be opened and closed by a suitable trigger mechanism 77. A source of power for each motor is provided by means of power wires 78 and 79 which may supply direct current of opposite polarity, or alternating current of different phase, depending on which is readily available. It is customary and preferable to install circuit breakers 81 and 82, or other suitable current limiting means, such as fuses, (not shown), in the present system, although this is not necessary to the invention if it is desired to take the risk of burning things up if something abnormal occurs.

Tracing the wiring circuit starting with line 78 and circuit breaker 81, the line splits into two lines 83 and 84, line 84 then splitting into two lines 86 and 87 attached to one pole of motors 28 and 29 respectively. The other line 83 runs through the solenoid of a relay 88 to wire 51, pipe 52, mercury 53, and if mercury 53 and wire 49 are in contact, through wire 49 to junction 89 where it splits into wires 91 and 92.

Wire 91 has a series of connections 93, 94 and 96 which each lead to one electrode of a tilting mercury switch 97 comprising an electrically non-conducting curved chamber containing some mercury 99. When this chamber is glass, or clear plastic, there is the added advantage that one may check the position of the mercury by looking through it. When mercury 99 contacts both wires 93 and 101 in one of switches 97, the circuit is completed to let electrical power which reached wire 91 in the preceding paragraph pass from 91 through 93, 94 or 96 and its respective switch 97 to the respective return wires 101, 103 or 104 and then to wire 102 through circuit breaker 82 back to the opposite side 79 of the power source 78 and 79.

Thus switch 97 in unit 63 and the corresponding switches in dispensing units 64 and 65 provide a plurality of rst connecting means each located adjacent one of said dispensing switches, any one of which said rst connecting means connects the power source to a rst one of said motors 28 or 29 as will be described later.

Wire 92 splits into two branches 106 and 107. Branch 106 goes to the pivot of one blade 108 of a double blade double throw reversing switch generally designated as 109.

When blade 108 is thrown to the left into contact with contact 111, it then connects to one pole of motor 29 by wire 112, and blade 113 (which is forced to move with the blade 108 by rigid insulated connection 114) contacts at 116 to connect one pole of motcr 28 through wires 117 and 118 with wire 107, provided relay 88 closes switch 119 to connect to wire 107. Obviously, when the reversing switch 108 is moved to the right to engage the other set of contacts pole 112 of motor 29 is then connected to wire 118, and pole 117 of motor 28 is then connected to wire 106.

Each of said rst connecting means comprises said tiltable mercury switch 97 mounted on a movable member 121 pivoted to housing 70 at 122 having an open bifur- S cated end 123 to receive the shut-on? valve housing 76 on the end of hose 73. `Movable member 121- is biased upwardly against gravity by compression spring 124 p when valve housing '76 is removed until thev top`of`member 121 contacts the top Vof slot 126, tilting switch"97 so that mercury 99 contacts both 93`and 101, but when the weight of the hose 73 is added' to end 123 of member 121 by placing valve 76 thereon,"member 121 moves down'into the position shownl in Figure 1 contacting me bottom of slot 126V and tilting switch597 so that mercury `99 fails to contact both 93 and 101, which breaks the circuit between them.

lFigure 2"sh`ows a" modified" system," similar in many ways to Figure l, which system illustrates 'chiey how the system of Figure 1 can be expandedto add more pumps,

V and how the uid being dispensed can be a fluid having a equipped to burn the same,or liquid 128 and gas 129 may be replaced by a continuous gaseous phase, because the present invention applies justas well to the handling of Vgases as liquids. ABecause of the'high vapor pressure of gas 129, it is necessary to providepressurevent line 131 with a pressure relief valve 132`set so it only relieves pressure through outlet 133 when the pressure'in space 129 is approaching a dangerously high pressure. Filling 1ine134 is the same as correspondingl'part 12 of Figure 1 in function, but valve 136 and threaded connection 137 prevent loss of vapor during and after iilling.

A single dip tube 138 is provided for withdrawinglliquid (or gas if there is no liquid phase)from tank-127 and splitting the same to inlets 139; 141: and klv'142 of pumps '143,144 and 146 respectively. The output of these pumps is combined in manifold 1471 and if the' pressure therein is above a predetermined maximum pressure set by relief valve 148, the pressure is reduced bypassing some of the iluid throughbypass line 149 and relief valve 148 back to line 138. The fluid from manifold 147 normally passes through discharge line 37, yand ow restrictor 42, which are given these numbers because they are the same as in Figure l, and said discharge line runs to a series of dispensinglines (not shown) similar to lines 38, 39 and 41 leading to dispensing stations-similar to 63, 64 and 65 of Figure l, each one of which isprovided with means for operating switches 97, 151, 152, 153 and 154 respectively which are like switches 497 in Figure 1. Dilerential pressure responsive electrical switching means 156 is similar to means`46 of Figure l except that there are two electrode wires'157 and 158 inplace of the one wire 49, the second wire 157 obviously completing its circuit responsive to a higher predetermined minimum pressure than wire 158, vwire 157 connecting a third motor to a power source. For each additional motor another wire can be added above wire 157. As pointed out above, some types o-f positive pumps 143, 144 and 146, such as gear pumps, may need no check Valves, however, if they do, check valves like 30 of Figure l can be inserted in their individual inlet or outlet lines.

In Figure 2 starting with power source 78, the same as in Figure 1,'the current passes through circuit break- Aer 81 into wire 159 which runs to one pole of each of motors 161, 162 and 163. Wire 159 has three branching wires 164, 165 and 166 connected thereon running through relay solenoids 167, 200 and 168 respectively to wires 158, 190 and 157 respectively.

The opposite poles of motors 161, 162 and 163 are connected to wires 169, 171 and 172 respectively. There are' vprovided three three-contact' single blade switches 'gangedtogetlier by'an operating member and generally designated'as`184. The'wire`1`69 runs to 4the four oclock contact173 of one switch, the` eight oclock contact 174 of the second'and the twelve oclock contact 176 ofthe third', while wire 171 runs tothe eight oclock contact 177,"the twelve oclock' contact 178,` and the' four oclock contact 179, and'wire 172 runs tothe twelve oclock contact 181,' the' four oclck Contact 182, andthe eight oclock contact`183. Any/"three of these contacts which are atthesame position on 'each off the three dials will be picked up by'the blades of'said gang'switch184 'and thus connected to "wires 186, A187, and 188 respectively.

For each additional motor, one more dial and one more contact on each dial should be added V(not shown). When anyoneof switches I97,"'151,'152, 153 or 154 is closed l by the attendant pickingV up the respective one of nozzles 176011 ofhook 123, current passes from 78 through 81, 159,'165, 200, 190," the respective switch 97, 151, 152,

`153 or 154, parts 1:02,' and 82 to 79, and coil 200 closes relay switch'185 V'starting themotor connected to wire 186 by completing the circuit'186, 185, "195, 194, 193,102. and 82 to 79. A 4

1'The motor whose'pole is"connected to wire 187 remains inoperative until the "pressure difference in '156 isf sucient to drive mercury 53 into contact with wire f 158, whereuponfcurrent travelsfrom source 78 through 81,-159-,1164, relay"coil-167, wire 158, mercury 53, wire 189, wire-190,-` the closed one of lswitches 97 and 151 to 154; wire-102,iancl part-'82 to source 79. This energizes solenoid V-167 pulling switch 191 shut against the force t oflspring'l192 completing the `circuitbetween Wires 193 vand-187. The -motor fwhlose'pole is connected to 187` is thenenergized by-cur'rentfstarting from 78 and passing through I81, 159,thelrespective-motor connected to line 187, switchf191, line-:193, line5102,- and circuit breaker `82 to'source'79.

In a similar manner when the'diierential pressure in Vv156 becomes great enough so that the mercury climbs to cal switch generally designated as 196 which can be substituted for the ones shown in Figures 1 and 2 by connectlng pipes 197 and 198 -to pipe 37 of Figures 1 or 2 at points 43 and'44 respectively. One advantage of the modification shown in Figure 3 is that it is readily adjustable, as by screwing cap 199 in'or out on body 201 it is easy to vary the compression of compression spring 202. This will make the glass switch 210 containing mercury 99 close-the circuit first between wires 203 and 204,and then between wires 203, and 206, at'diferent predetermined pressures, as the pressure in bellows 207 and 208 varies, and lever 209 rotates around the pivot at `211, tilting the glass switch'195.

In Figure 1, pumps 23 and 24 were centrifugal pumps, which reach a certain pressure and then allow liquid to slip,` so that they never exceed a certain pressure. In Figure 2, however, the pumps may also be positive displace-pumps, -such as piston pumps, or gear pumps, and therefore it isjessential that there be a relief valve bypass 148 to discharge any excess pump capacity.

In operation, when one or more of the dispensing nozzles 76 is placed in operation, one pump will start and will continue to supply the dispensing nozzles until the combined flow through all the open nozzles exceeds a predetermined rate which will be near, but below the discharge capacity of said first pump. This increased ow through orice 42 will cause an increased pressure drop across this orice above a predetermined minimum which will closediiferential pressure switch 46 of Figure l, 156 of Figure 2, or 196 of Figure 3 as to wires 49, 158

v and 204 respectively, which will operate relay 88 of Figure 1, or 167 of Figure 2, as the case may be, starting a second pump. This second pump will continue to operate until the combined dispensing flow rate falls below the predetermined rate allowing the differential pressure switch to open. In Figure 2 where there is a third motor and a third contact 157 an even greater pressure differential will start the third motor and drive a third pump, and the devices of Figure 3 can be substituted for 156 of Figure 2 by connecting wires 203, 204 and 296 in place of wires 189, 158 and 157 respectively and connecting pipe 197 in place of 43 and 198 in place of 44 respectively to pipe 37 upstream and downstream of oriice 42 respectively.

It will be noted in Figure l that the current for both motors 28 and 29 returns through wire 91, switch 97 and wire 191 to wire 102. This is quite all right when small motors are involved, and actual service station installations like this have been made and are successful. With larger motors, however, it is not desirable to have all the motor current going out to the dispensing points 70 'and going through switch 97. Figure 2 shows that this can be avoided by the use of relay switches 179, 135 and 191 on separate return lines of the motors which bypass switches 97, 151, 152, 153 and 154 through wires 195, 194, 193 and 102, the current in line 190 being much smaller than the motor current in line 193 because of the high resistance of coils 167, 168 and 290 designed for this purpose.

Figure 4 shows how the wiring of parts 49, 51, 83, 88, 89, 91, 93, 97, 101, 102, 106, 118 and 119 of Figure l can be rearranged to keep the motor current out of switch 97 in the same manner as in Figure 3. A relay consisting of a coil 211 and a switch 212 biased open by spring 213 is added and the connections made as shown. Motor current goes through switches 119 and 212 only, while the ohmic resistance in coils 88 and 211 limit the current across switch 97.

While an illustrative embodiment of the invention has been shown for purposes of illustration the invention obviously is not limited thereto.

Having described my invention, I claim:

l. A pumping system comprising in combination a plurality of iiuid pumps each having an outlet, a discharge line, a manifold connecting said outlets and said discharge line, a iiow restrictor diaphragm orifice plate in said discharge line, a motor connected to drive each pump, a source of power for each motor, a differential pressure responsive means responsive to the difference in pressure in said discharge line on opposite sides of said flow restrictor diaphragm oriiice plate, rst connecting means connecting said source of power to one of said motors, and second connecting means responsive to said difference in pressure when above a predetermined minimum to connect a second one of said motors to said power source.

2. A iluid dispensing system, comprising in combination a storage tank, a plurality of pumps, a motor driving each pump, said pumps each having an inlet conduit connected to said tank and an outlet conduit manifolded into a discharge line, a How restrictor diaphragm orifice plate in said discharge line, a dilerential pressure responsive means connected and disposed to be responsive to the difference in pressure in said discharge line on opposite sides of said ow restrictor diaphragm oriiice plate, a plurality of dispensing lines connected to said discharge line, a dispensing shut-oit valve adjacent the downstream end in each dispensing line, a source of power for each motor, a plurality of rst connecting means, any one of said first connecting means connecting said power source to a iirst one of said motors and a further connecting means responsive to said difference in pressure when above a predetermined minimum to connect said second Yone of said motors to said power source and to disconnect said second one of said motors from said power source when said difference in pressure falls below said minimum.

3. A fluid dispensing system, comprising in combination a storage tank, a plurality of pumps, a motor driving each pump, said pumps each having an inlet conduit connected to said tank and an outlet conduit manifolded into a discharge line, a ow restrictor diaphragm on'- iice plate in said discharge line, a dilerential pressure responsive means connected and disposed to the difierence in pressure in said discharge line on opposite sides of said flow restrictor diaphragm orifice plate, a plurality of dispensing lines connected to said discharge line, a dispensing shut-off valve adjacent the downstream end in each dispensing line, a source of power for each motor, a plurality of iirst connecting means, any one of said rst connecting means connecting said power source to a iirst one of said motors, a second selective connecting means for selecting said first one of said motors to be connected by said iirst connecting means and a second one of said motors to be connected by said second connecting means, and a further connecting means responsive to said difference lin pressure when above 'a predetermined minimum to connect said second one of said motors to said power source.

4. A fluid dispensing system, comprising in combination a storage tank, a plurality of pumps, a motor driving each pump, said pumps each having an inlet conduit connected to said tank and an outlet conduit manifolded into a discharge line, a ilow restrictor diaphragm orifice plate in said discharge line, a differential pressure responsive means connected and disposed to be responsive to the difference in pressure in said discharge line on opposite sides of said flow restrictor diaphragm orice plate, a plurality of dispensing lines connected to said discharge line, a dispensing shut-oit valve adjacent the downstream end in each dispensing line, a source of power for each motor, a plurality of first connecting means, any one of said rst connecting means connecting said power source to a rst one of said motors, said rst connecting means connecting said power source to said second connecting means, and a further connecting means responsive to said dierence in pressure when above a predetermined minimum to connect said second one of said motors to said power source.

5. A fluid dispensing system, comprising in combination a storage tank, a plurality of pumps, `a motor driving each pump, said pumps each having an inlet conduit connected to said tank and an outlet conduit manifolded into a discharge line, a flow restrictor diaphragm oriice plate in said discharge line, a differential pressure responsive means connected and disposed to be responsive to the difference in pressure in said discharge line on opposite sides of said iiow restrictor diaphragm orice plate, a plurality of dispensing lines connected to said discharge line, a dispensing shut-oli valve adjacent the downstream end in each dispensing line, a source of power for each motor, a plurality of rst connecting means, any one of said rst connecting means connecting said power source to a first one of said motors, and a further connecting means responsive to said diiierence in pressure when above a predetermined minimum to connect said second one of said motors to said power source.

6. A liquid dispensing system comprising in combination a supply tank for said liquid, a plurality of pumps, each pump including a liquid inlet connected to said supply tank and an outlet, a single discharge line, a manifold connecting all said pump outlets to said discharge line, an electric motor connected to drive each pump, a source of electrical power for said motors, a irst electrical switch responsive to a predetermined rate of low of the discharge of said pump at a point in said discharge line, a plurality of dispensing lines connected to said discharge line downstream of said point, a dispensing valve in each dispensing line, a second manual electrical switch adjacent each dispensing line, said second switches being connected in parallel so that upon manual actuation any one will connect said electrical power to a first of said electrical motors to drive a rst of said pumps, and said first electrical switch automatically connecting said power to a second of said electrical motors to drive a second of said pumps whenever the rate of flow in said discharge line exceeds said predetermined amount.

7. A pumping system comprising in combination a plurality of uid pumps each having an outlet, a discharge line, a manifold connecting said outlets and said discharge line, an electric motor connected to drive each pump, a source of electrical power for each motor, a rst electrical switch responsive to a predetermined rate of flow of the discharge of said pumps at a point in said discharge line, a plurality of dispensing lines connected to said discharge line downstream of said point, a dispensing valve in each dispensing line, a second manual electrical switch adjacent each dispensing line, said Second switches being connected in parallel so that upon manual actuation any one will connect said electrical power to a rst of said electrical motors to drive a rst of said pumps, and said rst electrical switch automatically connecting said power to a second of said elec trical motors to drive a second of said pumps whenever the rate of ow in said discharge line exceeds said predetermined amount.

8. The combination of claim 7 in which said rst electrical switch is responsive to a plurality of different ow rates and controls a plurality of electrical motors, turning more of said motors on as greater predetermined ow rates are exceeded, and turning said motors off when said ow rates are no longer exceeded.

9. The combination of claim 7 in which a master switching means is provided to manually select which motor is to be actuated by said first switch and which motor is to be actuated by said second switch.

10. The combination of claim 7 in which a portion of each of said dispensing lines is exible, in combination with a base, a member movably mounted on said base disposed to support said exible portion when not in use, and means disposed and connected to bias said movable member away from said base and to thereupon automatically close the adjacent one of said second manual electrical switches when said flexible portion is removed from said movable member.

References Cited in the le of this patent UNITED STATES PATENTS 1,566,591 Goldsmith et al Dec. 22, 1925 1,633,483 Graham June 21, 1927 2,029,085 Sussin Jan. 28, 1936 FOREIGN PATENTS 430,701 France Aug. 19, 1911 UNITED STATES PATENT OFFICE Patent No. 2,797,846 July 2, 1957 Edwin E.. Reed It is hereby certified that error appears .in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 8, line 9, after "disposed" insert to be responsive Signed and sealed this 19th day of November 1957.

(SEAL) Attest:

KARL H AXIINE ROBERT c. wA'rsoN Curmissioner of Patents Attesting Officer

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