US2919832A

US2919832A - Automatic multiple loading pump system

Info

Publication number: US2919832A
Authority: US
Inventors: Eugene D Lea
Original assignee: Phillips Petroleum Co
Current assignee: Phillips Petroleum Co
Priority date: 1958-01-09
Filing date: 1958-01-09
Publication date: 1960-01-05
Anticipated expiration: 1977-01-05

Description

, Jan. 5, 1960 E. D. LEA

AUTOMATIC MULTIPLE LOADING PUMP SYSTEM 2 Sheets-Sheet 1 Filed Jan. 9, 1958 INVENTOR.

E D LEA ATTORNEY;

Jan. 5, 1960 Filed Jan 9, 195a AIR RELAY RESTRICTION BALANCING E. D. LEA 2,919,832 AUTOMATIC MULTIPLE LOADING PUMP SYSTEM 2 Sheets-Sheet 2 INVEN'IKOK. E. D. LEA

BY w

ATTORNEYS operations.

United States Patent AUTOMATIC MULTIPLE LOADING PUNIP SYSTEM Eugene D. Lea, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Application January 9, 1958, Serial No. 707,993

18 Claims. (Cl. 222-4) This invention relates to method and/or combination of apparatus for automatically controlling the sequential operation of a plurality of fluid supply units, or pumps, in a fluid distribution system. In accordance with one aspect, this invention relates to an improved method of control and control system for automatically controlling sequentially the operation of a plurality of fluid supply units, or pumps, in a fluid distribution system in response to changes in the fluid flow demand of said system. In accordance with another aspect, this invention relates to an improved method of control and pneumatic control system for automatically controlling sequentially the operation of a plurality of pumps of equal or unequal capacity in a fluid distribut on system handling liquid hydrocarbon, for example, in response to changes in the fluid flow demand of said system. In accordance with another aspect, this invention relates to an improved method of control and pneumatic control system for automatically controlling sequentially the operation of a plurality of pumps of equal or unequal capacity pumping liquid hydrocarbon, for example, hydrocarbon fuels, to a vehicle loading zone in response to changes in the loading zone fluid flow demand which is proportional to the number of vehicles being simultaneously loaded.

Currently employed equipment for the filling of vehicles such as, tank cars, tank trucks, such as used to convey and dispense gasoline, oil, and by-product liquids, etc., involves a loading rack with a plurality of vertical standpipes and overhead connected swing arms, and an elevated platform for the operators and loaders. The tank cars or trucks are normally filledthrough capped openings in the top of the tanks and this requires facilities as described, to enable the workmen to reach such filling openings. it is also known to be more economical in the handling of fluids, for example, loading of hydrocarbon fuels at a tank car or tank truck loading rack, to employ several small pumps rather than one equivalent large capacity pump where several loading spouts are utilized. However, in using a number of smaller pumps, the problem of quickly starting and stopping the pump as required to supply the continuously varying loading demand at the loading rack becomes increasingly difiicult. A number of control systems have been either proposed or used for the operation of multiple pumps, but the prior art control systems are usually limited in their operation for one reason or another. For example, electrical control systems present a fire hazard when employed in loading rack areas to load combusible materials such as hydrocarbon fuels. Other systems are not entirely reliable or accurate. Thus, there is a distinct need in industry for a safe, reliable control system for hydrocarbon loading According to the present invention, method and apparatus are provided eliminating the hazards normally associated with the prior art systems but which still are capable of effectively and accurately performing the loading operation.

. Accordingly, an object of the present invention is to provide'a relatively simple, reliable,,and eficient com- 2,919,832 Patented Jan. 5, 1960 bination of control elements for automatically pneumatically controlling the sequential operation of a plurality of pumps in a vehicle loading system loading hydrocarbons.

Another object of this invention is to provide a novel improved filling system for loading vehicle mounted tanks.

Another object of this invention is to provide an improved method and arrangement of pneumatic control elements in a vehicle hydrocarbon loading area which eliminates the hazards normally present with conventional control systems.

Another object of this invention is to provide a vehicle loading system which is flexible, simple, and safe in operation.

Another object of this invention is to provide a pumping system employing a plurality of pumps wherein the liquid flow is controlled by the demand at the dispensing point.

Other aspects, objects, and advantages of the invention will be apparent to those skilled in the art in view of this disclosure.

Thus, in accordance with a broad concept of the present invention, 1 provide an improved method of control and pneumatic control system for varying the fluid output of a pumping zone supplying fluid through a fluid distribution system to a dispensing zone, said dispensing zone being adapted to continuously dispense variable quantities of fluid comprising, passing a pneumatic signal proportional to fluid flow demand of said dispensing zone from said dispensing zone to a pneumatic pressure balancing zone, said balancing zone being adapted to automatically vary the fluid flow output of said pumping zone in response to changes in said pneumatic signal.

In accordance with a narrower concept of my invention,

I provide an improved method of sequentially operating a fluid distribution system to a liquid dispensing zone comprising, flowing said liquid from a storage zone to said pumping zone to elevate the pressure of said liquid, introducing said liquid of elevated pressure into said distribution system, passing said liquid through said system to said dispensing zone, said dispensing zone adapted to dispense liquid continuously in varying quantities, passing a first pneumatic signal proportional to the liquid flow demand of said dispensing zone from said dispensing zone to a pneumatic pressure balancing zone for energizing and de-energizing said pumps successively, passing a second pneumatic signal proportional to said liquid flow demand from said balancing zone to a pneumatic signal switch zone operable automatically to energize and de-energize said pumps in sequence, and a time control zone for maintaining one of said pumps in operation a predetermined time after said automatic switch zone is operated to de-energize the one said pump, thereby automatically putting said pumps individually into and out of service to vary the liquid output of said pumping zone responsive to the flow demand of said dispensing zone.

In accordance with another concept of my invention, I provide an improved arrangement of apparatus and pneumatic control elements for controlling the operation of a plurality of fluid supply units, or pumps, pumping fluid under pressure through a fluid distribution system to a plurality of dispensing means comprising, in combination; conduit means for conveying said fluid from storage means through said pumps to said dispensing means; a power source for operating each of said fluid supply units;

matic flow control valve means; pneumatic pressure balancing means connected to said control valve means.

operable automatically in response to pneumatic pressure changes which is proportional to the fluid flow demand of said dispensing means supplied by said loading means for energizing and deenergizing said pumps successively; pneumatic signal switch means connected operable automatr cally to energize and de-energize the power source of said pumps in sequence; and time delay means interposed oetween said switch means and one of said pumps for maintaining one said pump in operation a predetermined time after said switch means is operated to de-energize one said pump.

Figure l is a diagrammatic flow sheet illustrating schematicaliy a hydrocarbon fuel vehicle loading system of the present invention.

Figure 2 is a partially cut away sectional elevation of one combination of a pneumatic pressure balancing unit and pneumatic signal sequential switch element which can be employed in the present invention for automatically putting the vehicle loading pumps into and out of service.

Figure 3 is a sectional plan view of the pneumatic pressure balancing unit howing one arrangement of the balancing bellows that can be employed in the present invention.

Figure 4 is a sectional plan view of the lower portion of the pneumatic pressure balancing unit showing one arrangement of the input bellows elements.

Referring now to the drawings, wherein like numerals have been employed to designate like elements of apparatus, the invention will be more fully explained. it is to be understood that said drawings are diagrammatic in nature and may be altered in many respects by those skilled in the art and yet remain within the scope of my invention. Many valves, pressure gages, relays, etc., not necessary for explaining the invention to those skilled in the art, have been omitted so as to simplify said draw ings. Substantially all of the individual elements shown in said drawings are commercially available conventional equipment. The present invention resides primarily in the combination and arrangement of said elements to obtain the improved results as described herein.

In Figure 1, a liquid hydrocarbon material, such as an internal combustion engine fuel, is suppled to bulk storage tank 19 by way of valved conduit 11 from a source of supply, such as a refinery or other hydrocarbon processing area, not shown. It will he understood that tank is only one tank of a group of tanks of ready storage of which only one is shown here. The liquid hydrocarbon material to be loaded is removed from tank It by way of valved conduit 12 and passed into pump suction manifold 13 for introduction into one or more electric motor driven pumps 14, 15, and 16. It will be understood that pumps 14, 15, and 16 can be any type of conventional pump such as centrifugal, reciprocating, and the like. Similarly, the pumps can be driven by any well known conventional drives such as electric motors, steam turbines, and the like; however, as shown in Figure 1, I prefer to employ electric motor driven centrifugal pumps. The liquid hydrocarbon material is discharged from pumps 14, 15, and 16 into header 17 and passed by way of conduit 18 to the vehicle loading area wherein the hydrocarbon is introduced into a loading dock pipe header 19. A plurality of valved loading spouts 20, 21, 22, 23, 24, and 25' are operatively connected to header 19 for passing the liquid material to be loaded to a vehicle, for example. As shown in Figure 1, loading spout 20 is ready for use to load tank car 26; however, tank trucks and other units could also be loaded by the prment system. Valves 27-32 in loading spouts 20-25, respectively, are operatively connected through a shaft (not numbered) to manually operated four-way valves 33-38, respectively, having handles (not numbered) operatively connected thereto. The four-way valves employed can be any conventional well known four-way air switch or valve. One particular desirable 4 valve is the Foxboro multi-way air switch such as described in Foxboro Bulletin DMF-798.

As shown in Figure 1, valves 27-32 are shown as manually operated gate valves, for example, and are connected by a shaft to the handle mechanism operating four-way valves 33-38. It should also be realized that other valve arrangements can be satisfactorily employed. For example, a diaphragm motor valve can be placed in the loading spout conduits, and two four-way valves on a common axis can be connected to the instrument air conduits 44-49. One four-way valve admits air to the diaphragm motor valve on the loading spout and the other four-way valve admits air to the bellows-balancing unit 56.

Instrument air is introduced into instrument air pipe header 42 via conduit 40 and pressure reducing valve 41. A pressure indicator 43 is also provided in conduit 40. The pressure of the instrument air in conduit 40 can be 40-50 p.s.i. air, for example, whereas the pressure in header 42 can be 1-2 p.s.i. air depending upon the number of loading spouts employed. The instrument air in header 42 is passed through conduits 44-49, four-way valves 33-38, conduits 50-55, and introduced into air pressure balancing bellows unit 56, the operation of which is to be described more fully in connection with the discussion of Figures 2-4. As shown in Figure 1, each of the four-way valves is connected at one port to the instrument air conduits, and the port 90 removed on each valve is connected to the conduit leading to bellows-balancing unit 56. The third port of each of the four-way valves is connected to a common bleed. The fourth port of the four-way valves can be conveniently connected to another bellows-balancing unit similar to unit 56, sequential pneumatic signal, switches, motor starters, etc., when a second product is to be used and loaded through the same vehicle loading spouts shown in Figure 1. A second source of instrument air for the system, for example, air under 40-50 p.s.i. pressure, is passed by way of conduit 57, pressure reducing valve 58, pressure indicator 59, restriction 60 such as an orifice or venturi, and a portion of the instrument air of reduced pressure, usually 15-20 p.s.i., is introduced into bellowsbalancing unit 56 via conduit 62, and the remainder is passed to air relay 63- via conduits 61 and 64. Air introduced into relay 63 by conduit 64 passes through a pilot valve within said relay and removed from the air relay by way of conduit 65 and a portion of this air is introduced into bellows unit 56 and the remainder is passed via conduit 67 to a sequential pneumatic signal switch housing 68, there being three sequential pressure switches 88, 89, and actuated by bellows 91, 92 and 93 (Figure 2) within said housing in the present embodiment. The sequential pneumatic signal switches employed can be any well known conventional pneumatic operated type sequential signal switch such as the type sold by the Mason-Neilan Regulator Company shown and described in their bulletin D-7995, pages 1-7.

The sequential switches in housing 68 are operativ'ely connected to a source of electrical power (not shown) and to motor starters 70, 71 and 72 which are connected by electrical leads 73, 74 and 75, respectively, to the motors (not shown) on pumps 14, 15, and 16, respectively. A time delay relay 69 is positioned between motor starter 72 and its assoicated sequential pressure switch 88. Time delay relay 69 is employed to delay the shutting down of pump 16 through starter 72 to insure adequate supply of fluid to loading until the meter is finally shut off by its automatic shutoff device (not shown).

Referring now to Figure 2, instrument air passed by way of conduits 50-55 is divided into two substantially equal streams for each conduit before introduction into pneumatic pressure balancing-bellows unit 56. Thus, for instrument air fiow through each conduit 50-55, there are two streams of air entering bellows unit 56 and each stream has a corresponding input bellows element positioned within unit 56 and operatively connected to the instrument air inlet conduits. As can be seen from Figures 2 and 4, the bellows elements and air inlet conduits are symmetrically arranged within the housing of unit 56, and, further, the pair of bellows elements for each conduit 50-55 is spaced diametrically from each other. Thus, instrument air passed through conduits 50 and 50' is introduced into their corresponding input bellows elements 76 and 76', respectively. Similarly,

conduits

51 and 51, 52 and 52', 53 and 53' 54 and 54 and 55 and 55 pass instrument air to bellows

elements

77 and 77, 78 and 78, 79 and 79', 80 and 80', and 81 and 81', respectively.

Referring now to Figure 2 again, a balancing plate 82 is disposed on top of the input bellows elements. The plate can be any suitable light weight or thin circular plate material large enough to cover all of the input bellows elements. Positioned above plate 82 are larger balancing bellows

elements

83, 84 and 85 which are operatively connected to instrument air conduit 66. A suitable vent, as shown, can be provided in unit 56 so as to bleed instrument air from the bellows housing. Also positioned Within the upper portion of unit 56 is a nozzle element 86 adjustable by screw element 87 that is operatively connected to instrument air conduit 61 and air relay 63. As shown by Figure 2, the bellows elements, nozzle, and balancing plate are all contained within a housing. Referring to Figure 3, it can be seen that bellows

elements

83, 84, and 85 are symmetrically spaced and the nozzle is positioned substantially in the center of unit 56. It should be realized that other geometric arrangements of the bellows elements and other housing shapes can be advantageouslyemployed without departing from the operativeness of the balancing bellows unit employed in the present invention.

Bellows

elements

83, 84, and 85 are connected to instrument air conduit 66, which is connected to air relay 63, and a portion of the instrument air passed through relay 63 is thus passed to

bellows elements

83, 84 and 85 to effect balancing forces on plate 82 within unit 56. The remainder of the air passed through relay 63 is introduced into bellows elements 91, 92, and 93 positioned within switch housing 68 for actuation of switches 88, 89, and 90 sequentially in response to changes in the flow of instrument air through relay 63.

Referring now to Figures 1 and 2 particularly, the operation of the present control system will be described in detail. As shown in Figure 1, only one tank car is positioned at the loading area to be loaded with a liquid hydrocarbon fuel, for example, stored in tank 10. When there are no vehicles being loaded the loading spout valves and four-way valves are all closed. However, when it is desired to load vehicle 26, for example, the operator turns the handle (not numbered) that is directly connected to loading spout valve 27 and four-way valve 33 to open both valves. By opening valve 27, fuel can be subsequently introduced into tank car 26. Likewise, by turning four-way valve 33, instrument air in header 42 and conduit 44 passes through valve 33, conduit 50 and 50' (Figure 2), and then introduced into bellows elements 76 and 76' (Figure 3) positioned within bellows-balancing unit 56. Admission of instrument air into

bellows elements

76 and 76 causes an expansion of the two bellows elements, thereby effecting a lifting of balancing plate 82 toward nozzle 86.

Since instrument air is continuously flowing through conduit 57, pressure reducing valve 58, restriction 60, and a portion of this air passes through conduit 62 and is introduced into balancing unit 56 through nozzle 86, a lifting of balancing plate 82 by bellows elements 76 and 76' narrows the distance between the end of nozzle 86 and plate 82, thereby resulting in a smaller fiow of air into unit 56 through conduit 62, which in turn effects afgreater pressure or the flow of air-through conduit 61 into air relay 63. This increase of air pressure in conduit 61 effects the further opening of a pilot valve (not shown) positioned within air relay 63. Opening of the pilot valve within relay 63 allows additional air to How through the relay introduced by way of conduit 64, and removed by the outlet conduit, and returned to

bellows

83, 84, and within balancing unit 56 by conduit 66. The introduction of air into

bellows elements

83, 84, and 85 effects balancing forces on balancing plate 82, thereby providing a more sensitive and accurate balancing instrument. Similarly, an increase in air flow through relay 63 produces a corresponding increase in air flow through conduit 67 passed to bellows elements 91, 92, and 93 positioned within sequential switch housing 68.

The amount of air flowing through conduit 67 and introduced into bellows elements 91, 92, and 93 is relatively small with only one loading spout operating and, therefore, only switch 88 is closed due to the expansion of bellows element 91. The system is so balanced that with one or two loading spouts simultaneously operating, for example, only switch 88 operated by bellows element 91 is closed. Since the switches in housing 68 are connected to a source of electrical power (not shown), closing of switch 88 passes an electrical signal throughtime delay relay to motor starter 72, which in turn energizes the electrical motor connected to pump 16, thereby starting up pump 16 for transfer of liquid to the loading spouts. As previously pointed out, time delay relay 69 is used to delay shutting down of pump 16 through starter 72 to insure adequate supply of fluid to loading until the meter is finally shut off by its automatic shut oif device, not shown. The time delay device can be set for any desired predetermined time in delaying the shutting down of pump 16.

The above described operation involves only the loading of a single vehicle at one time. When more vehicles are to be loaded, simultaneously, additional loading spout valves and their corresponding four-way valves are likewise opened. Opening of additional four-way valves passes more air to bellows-balancing unit 56, thereby effecting a further lifting of balancing plate 82, which in turn pinches down the flow of air through nozzle 86. Cutting down the air flow through nozzle 86 causes additional air pressure to open up the pilot valve further within air relay 63, thereby allowing a greater flow of air into

conduits

66 and 67. This further increase in air flow in conduit 67 causes further expansion of bellows elements 91, 92, and 93 thereby closing switch 89 and 90, for example, and actuation of pumps 14 and 15 through starters 70 and 71. The present system is so adjusted and balanced that when three or four loading spout valves (2730) and their corresponding four-way valves (3336) are open for loading, the air pressure in conduit 67 is sufiicient to close switch 89 through bellows 92, thereby starting up pump 15 through starter 71. Similarly, with valves 31 and 32, and 37 and 38 also used for loading, i.e., all loading spouts are simul-' taneously being used, the additional air pressure in conduit 67 is suflicient to effect expansion of bellows 93 to close switch 90 and thus start up pump 14 via starter 70.

The shutting down of pumps after loading operates in reverse of the above described system. For example, closing of any two loading spout valves and four-way valves will result in a decrease in air flow to bellows unit 56, a corresponding proportionate decrease in air pressure in conduit 67, and, therefore, less air pressure is exerted on bellows element 93 and switch 90 is opened, which in turn cuts olf the electrical power supply to pump 14 through starter 70, which causes the shutting down of the operation of pump 14 for loading. Similarly, shutting off two more loading spouts will likewise shut down pump 15 in response to a decrease in air flow to units-56 and 68, and closing of all loading spout valves willfinally shut down pump 16.

It should be pointed out that it is not necessary that the loading spout valves be opened in any particular order in the practice of the present invention. As described in connection with Figure l, the loading valves were opened in order from 27-32; however, the reverse order, or random opening of the valves may be employed and the invention will be just as effective. Also, as pointed out previously, the control system of the present invention is so adjusted and balanced that with any one or two loading spouts being utilized for loading, one pump is operating; with any three or four loading spouts in operation, two pumps are operating; and with any five or six loading spouts operating, all three pumps are pumping liquid to the loading spouts.

As previously described, pneumatically operated pressure switches 38, 89, and 90 are preferably arranged to operate at slightly different pneumatic pressures so that they will act progressively. For example, the first switch 88 can operate at 15 p.s.i.g. air pressure, the second switch 39 at 17 p.s.i.g., and the third switch 98 at 19 p.s.i.g. Therefore, as the air pressure in conduit 67 increases the 15 p.s.i.g. switch or switch 88 is first actuated and closed thereby energizing pump 16 through motor starter 72. If the air pressure in conduit 67 increases to 17 p.s.i.g. switch 89 will be closed and pump 15 energized. if the air pressure in conduit 67 increases to 19 p.s.i.g. switch 90' will be closed and pump 14 energized. Obviously this arrangement can be continued to any number of pneumatic actuated switches and pumps, which it will be necessary to employ. If, on the other hand, the air pressure in conduit 67 drops to the point for which the switches are set to open, one after the other will open, thereby de-energizing the pumps in succession and as required to supply liquid to the dispensing means. The air pressure at which an open switch will close or a closed switch will open may be the same pressure or different pressures depending upon the cir cumstances. The air pressures given above are merely exemplary and may be varied to suit the circumstances of the particular installation.

It should be realized that any number of pumps as well as any suitable number of loading spouts may be conveniently employed in the practice of the present invention. For illustrative purposes, i have shown and described the use of six loading spouts, three pumps, and a bellows-balancing unit having twelve input bellows spaced below a balancing plate and three larger counterbalancing bellows spaced above the balancing plate; however, any suitable number of bellows elements, loading spouts, and pumps can be employed, if desired. Also, I have shown and described a loading system loading only one hydrocarbon liquid; however, as previously explained, the present invention can be easily adapted to load several different products through one loading rack by providing one or more additional bellows-balancing units, etc, connected to the four-way valves, and provision of additional storage facilities and pipe manifolding connections to the pumps as previously described.

In one plant operation, three tank cars of 10,000 gallon capacity each are spotted under loading spouts 20, 22 and 25 (as numbered in Figure 1.) With hatches opened and spouts in place, the operator opens valves 27, 29 and 32 in sequence. Upon opening valve 27 first, four way valve 33 is positioned to allow control air to flow by way of

lines

44 and 50 to bellows-balancing unit 56. The action through unit 56, as hereinabove-described, effects expansion of bellows 91 which actuatcs closing of switch 33 (as numbered in Figure 2), which, by way of starter 72, actuates starting of the motor on pump 16 to deliver gasoline from tank by way of line 18 to spout 2t for loading of the tank car thereunder. Pump 16 is capable of pumping gasoline at the maximum rate of 100 gallons per minute. However, spout 20 allows 50 gallons per minute maximum flow. The operator next opens valve 29 which acts to open also four-way valve 35 to admit additional air to unit 56. The additional flow of air via line 67 to the sequential pressure switch 58 is not sufficient to close switch 89, and at this time only pump 16 is operating. The total flow via pump 16 is now the maximum 100 gallons per minute, gallons per minute flowing into each of the tank cars spotted under spouts 20 and 22. The operator then opens valve 32 which acts to open also four-way valve 38 to admit additional air to unit 56. This additional air is suflicient to actuate bellows 92 to close switch 89 which starts the motor on pump 15. Pump 15 increases the total flow from tank 10 at the three cars so that they each may be loaded at the rate of 50 gallons per minute.

When the tank car under spout 20 is finished loading.

(and it is loaded first in this example since it started ;to receive gasoline first), valve 27 is closed. The air signal to unit 56 is simultaneously cut down, and bellows -92 relaxes to open switch 89 effecting the cutting-off of pump 15, which pump is not now needed for loading. When the car under spout 22 is loaded, the operator cuts off valve 29 which effects decreasing the air supply to bellows 91 but not sufiiciently to cause bellows 91 to open switch 88. When the tank car under spout 25 is filled, valve 32 is closed which sutficiently decreases air to bellows 91 to eflect the opening of switch 38 to shut down the operation.

Various other modifications of the invention can be made or followed in view of the above-disclosure, without departing from the spirit or scope of the invention, as will be apparent to those skilled in the art. While I have illustrated and described in detail certain preferred forms of my invention, it is to be understood that changes may be made therein and the invention embodied in other structures. I do not, therefore, desire to limit myself to the specific construction illustrated, but intend to cover my invention broadly in whatever form its prin ciples may be utilized.

I claim:

1. Method of continuously controlling the fluid flow output of a pumping zone adapted to pressure fluid through a fluid distribution system to a dispensing zone comprising a plurality of dispensing units having a variable fluid flow demand comprising, passing a pneumatic signal from each of said units of said dispensing zone proportional to the fluid flow demand at each of said units of said zone to a pneumatic pressure balancing zone, said balancing zone adapted to integrate the signals from each of said units being further adapted to automatically control the fluid flow output of said pumping zone in response to changes in said pneumatic signals.

2. Method of continuously controlling the fluid flow output of a pumping zone comprising a plurality of pumps supplying a fluid through a fluid distribution system to a vehicle fluid loading zone comprising a plurality of dispensing units having a variable loading demand comprising, passing a pneumatic signal from each of said dispensing units of said loading zone proportional to the loading demand of said zone to a pneumatic pressure balancing zone adapted to integrate the signals from each of said units, said balancing zone being further adapted to automatically control the fluid flow output of said pumping zone by putting said pumps individually into and out of service in response to changes in said pneumatic signals.

3. Method of continuously controlling the liquid flow output of a pumping zone comprising a plurality of pumps adapted to pump a liquid under pressure through a fluid distribution system to a liquid dispensing zone comprising a plurality of dispensing units adapted to dispense continuously variable quantities of liquid depending upon the liquid flow demand of said dispensing zone comprising, passing a first pneumatic signal from each of said dispensing units of said dispensing zone proportional to the liquid flow demand at each of said units of said dispensing zone to a pneumatic pressure balance ing zone adapted to integrate the signals from each of said dispensing units, passing a second pneumatic signal proportional to said first signal from said balancing zone to a pneumatic signal pressure control zone, said con trolled zone being adapted to automatically control the liquid flow output of said pumping zone in response to changes in said pneumatic signals.

4. Method of continuously controlling the liquid flow output of a pumping zone comprising a plurality of pumping units adapted to pump a liquid under pressure through a fluid distribution system to a vehicle liquid loading zone comprising a plurality of dispensing units adapted to continuously load variable quantities of liquid depending upon the liquid loading demand of said loading zone comp-rising, passing a first pneumatic signal from each of said dispensing units of said loading zone proportional to the loading demand at each of said units at said loading zone to a pneumatic pressure balancing zone adapted to integrate the signals from each of said units, passing a second pneumatic signal proportional to said first signals from said balancing zone to a pneumatic signal operable switch control zone, said switch control zone being adapted to automatically control the liquid flow output of said pumping zone in response to changes in said pneumatic signals.

5. Method of operating a plurality of pumps pumping a liquid hydrocarbon under pressure through a fluid distribution system comprising the steps of, passing said liquid hydrocarbon to a vehicle loading zone comprising a plurality of dispensing units within said system, passing a pneumatic signal from each of said dispensing units proportional to the liquid hydrocarbon loading demand of each of said units at said loading zone from said zone to a pneumatic pressure balancing zone, said balancing zone being adapted to integrate said signals and automatically putting said pumps individually into and out of service in response to changes in said pneumatic signals.

6. Method of operating a plurality of pumps, each having an individual source of power, pumping a liquid under pressure through a fluid distribution system comprising the steps of, passing said liquid to a vehicle load ing zone comprising a plurality of dispensing units within said system, passing a first pneumatic signal proportional to the liquid loading demand of each of said units at said loading zone from said zone to a pneumatic pressure balancing' zone adapted to integrate the signals from each of said units, passing a second pneumatic signal proportional to said liquid loading demand from said balancing zone to a pneumatically operated sequential signal switch zone, said switch zone being adapted for sequentially interrupting the source of power to said pumps within said switch zone in response to changes in said pneumatic signals, thereby automatically putting said pumps individually into and out of service responsive to said liquid loading demand.

7. Method of operating a plurality of pumps, each having an individual source of power, pumping a liquid under pressure through a fluid distribution system comprising the steps of, passing said liquid from a-source of supply to said pumps, passing said liquid from said pumps to a vehicle loading zone comprising a plurality of dispensing units within said system adapted to load a plurality of vehicles simultaneously, passing a first pneumatic signal from each dispensing unit loading a vehicle at said loading zone to a pneumatic pressure balancing zone adapted'to integrate the signals from each of said units, passing a second pneumatic signal proportional to the number of vehicles being loaded from said balancing Zone to a pneumatically operated sequential signal switch zone, said switch zone being adapted for sequentially interrupting the source of power to said pumps within said switch zone in response to changes in said pneumatic signals, thereby automatically putting said pumps individually into and out of service responsive to the num ber of vehicles being loaded in said'loading zone.

8. Method of operating a plurality of pumps, each having an individual source of power, pumping a liquid hydrocarbon under pressure through a liquid distribution system comprising the steps of passing said hydrocarbon from a storage zone to said pumps, passing said liquid hydrocarbon from said pumps to a vehicle loading zone comprising a plurality of dispensing units adapted to load a plurality of vehicles simulaneously within said system, passing a first pneumatic signal from each dispensing unit proportional to the number of vehicles being loaded with liquid hydrocarbon in said loading zone from said zone to a pneumatic pressure balancing zone adapted to integrate the signals from each of said units, passing a second pneumatic signal proportional to the number of vehicles being loaded simultaneously from said balancing zone to a pneumatically operated sequential signal switch zone, said switch zone being adapted for sequentially interrupting the source of power to said pumps within said switch zone in response to changes in said pneumatic signals thereby automatically putting said pumps individually into and out of service responsive to the amount of liquid hydrocarbon being pumped into said vehicles being loaded.

9. In combination with a fluid distribution system adapted to pass fluid to a place of variable demand; a source of fluid supply; a plurality of fluid supply unitsconnected to said source and to a common distribution line terminating in a plurality of dispensing means at said place of demand; pneumatic pressure balancing means connected to each of said dispensing means to obtain a pneumatic signal proportional to the flow demand for each of said dispensing means at said place, said balancing means being adapted to integrate the signals from each of said units and to individually interrupt the individual operation of said pumps, thereby putting said pumps into and out of service in response to changes in said pneumatic signal.

10. In combination with a fluid distribution system adapted to pass fluid to a place of variable demand; a

source of fluid supply; a plurality of fluid supply units connected to said source and to a common distribution line terminating in a plurality of dispensing means at said place of demand; pneumatic pressure balancing means connected to each of said dispensing means to obtain a first pneumatic signal proportional to the flow demand for each of said dispensing means at said place, said balancing means being adapted to integrate the signals from each of said units and deliver an output signal equivalent to the number of input signals; sequential switch means connected to obtain said output pneumatic signal, said switch means being adapted to sequentially interrupt the operation of said pumps, thereby putting said pumps into and out of service in response to changes in said signals. 11. In combination with a fluid pumping system adapted to pump fluid to a vehicle loading zone; a plurality of pumps connected to pass fluid under pressure into said system; a plurality of dispensing means at said loading zone connected to obtain fluid from said pumps; a plurality of pneumatic control valve means each operatively connected to said dispensing means; pneumatic pressure balancing means connected to each of said control valves and dispensing means to obtain a pneumatic signal from each of said dispensing means proportional to the fluid flow demand of each of said dispensing means, said balancing means being adapted to add said signals and deliver an output signal equivalent to the number of input signals applied; switch means actuated by said output signal, said switch means being adapted to individually -in-- supply; a' plurality of pumps connected to obtainfiuid from said supply; a plurality of dispensing means connected to obtain fluid from said pumps; a plurality of pneumatic flow control valve means each connected to iii].

said dispensing means; pneumatic pressure balancing means connected to obtain a pneumatic signal from each of said dispensing units proportional to the fluid flow demand of each of said dispensing means, said balancing means being adapted to add the input signals and deliver an output signal equivalent to the number of input signals applied; switch means actuated by said output signal, said switch means being adapted to individually interrupt the operation of said pumps, thereby putting said pumps into and out of service in response to changes in said signal.

13. In combination with a liquid pumping system adapted to pump liquid hydrocarbons to a vehicle loading area adapted to load a plurality of vehicles simultaneously; a source of liquid hydrocarbon supply; a plurality of pumps each having independent power means connected to obtain fluid from said supply; a plurality of dispensing means in said loading area connected to no tain liquid hydrocarbon from said pumps; a plurality of pneumatic flow control valve means each connected to said dispensing means; pneumatic pressure balancing means connected to obtain a first pneumatic signal from each of said dispensing means proportional to the amount of liquid hydrocarbon being loaded into said vehicle by each of said dispensing means, said balancing means being adapted to integrate the signals from each of said dispensing means and deliver an output signal equivalent to the number of input signals applied; sequential switch means connected to obtain said output pneumatic signal; said switch means being adapted to sequentially interrupt the operation of said pumps thereby putting said pumps into and out of service in response to changes in said signals.

14. In combination with a liquid hydrocarbon pumping system adapted to pump hydrocarbons to a vehicle loading area adapted to load a plurality of vehicles simultaneously; a source of liquid hydrocarbon supply; a plurality of pumps each having independent power means connected to obtain liquid hydrocarbon from said supply; conduit means connected to obtain fluid from said pumps; a plurality of valve dispensing means connected to obtain fluid from said conduit means; a plurality of pneumatic flow control valve means operatively connected to each of said valve dispensing means; pneumatic pres sure balancing means connected to obtain a first pneumatic signal from each of said dispensing means proportional to the liquid hydrocarbon flow through each of said dispensing means, said balancing means being adapted to integrate the signals from each of said units and deliver an output signal equivalent to the number of input signals applied; sequential pressure switch means connected to obtain said output pneumatic signal, said switch means being adapted to sequentially energizing and de-energizing said power means, thereby putting said pumps into and out of service in response to changes in said pneumatic signals.

15. In combination with a fluid distribution system supplying fluid to vehicle loading area having a plurality of dispensing means adapted to load a plurality of vehicles simultaneously, a series of independently operated pumps to supply fluid under pressure to said dispensing means, pneumatic balancing means connected to obtain a pneumatic signal from each of said dispensing means proportional to the flow of each of said means, said balancing means being adapted to integrate the signals from each of said means and delivering an output signal equivalent to the number of input signals applied and operating automatically in response to changes in a fluid flow demand of said loading means, pneumatic operating switch means operable automatically to energize and de-energize said pumps in said output sequence in response to changes in pneumatic signal from said balancing means, and time delays interposed between said pneumatic switch means and said pumps for maintaining one of said pumps in operation a predetermined time after said pneumatic balancing means has operated to de-energize one of said pumps.

16. In combination with a fluid distribution system supplying liquid to vehicle loading means comprising a plurality of dispensing means adapted to load aplurality of vehicles simultaneously, a series of pumps each having independent power means to supply liquid under pressure to said system from a source of liquid supply, pneumatic pressure balancing means connected to obtain a pneumatic signal from each of said dispensing means proportional to the flow of each of said means, said balancing means being adapted to integrate the signals from each of said means and delivering an output signal equivalent to the number of input signals applied and operating automatically in response to the increase and decrease of liquid flow demand of said loading means, pneumatic pressure operating switch means for energizing and dcenergizing said pumps in sequence for individuallyv interrupting said power means in response to said output pneumatic signal from said balancing means, and time delay means interposed between said switch means and said pumps for maintaining one of said pumps in operation a predetermined time after said balancing means ,has operated to de-energize one of said pumps.

17. A fluid pressure balancing means and fluid pressure operable switch means for successively operating a plurality of liquid supply units in sequence supplying liquid to dispensing means having continuously varying liquid flow demand in response to changes in said demand comprising in combination; conduit means conveying a first fluid pressure proportional to said liquid flow demand from said dispensing means; first fluid pressure expansible means connected to obtain said first pressure; second fluid pressure expansible means connected to obtain a second fluid pressure; partition means disposed between said first and second fluid pressure expansible means; fluid pressure exhaust means facing said partition means and so positioned that movement of said partition means controls the flow of said second fluid through said exhaust means and the pressure of said second fluid; fluid pressure operated switch means for sequentially energizing and de-energizing said liquid supply units in response to changes in the pressure of said second fluid.

18. A fluid pressure balancing means and fluid pressure control means for varying the output of a fluid supply unit of variable capacity supplying fluid to dispensing means having continuously varying flow demand responsive to changes in said demand comprising, in combination; means for conveying a first fluid pressure proportional to said flow demand at said dispensing means; first fluid pressure expansible means connected to obtain said first fluid pressure; second fluid pressure expansible means connected to obtain a second fluid pressure; partition means disposed between said first and second .fluid pressure expansible means; fluid pressure exhaust meansfacing said partition means and so positioned that movement of said partition means controls the flow of said second fluid through said exhaust meansand the pressure of said second fluid; fluid pressure control means actuatedby said second fluid for varying the output of said supply unit responsive to changes in the pressure of said. second fluid.

References Cited in the file of this patent UNITED STATES PATENTS 2,211,476 Nelson Aug. 13, 1940 2,246,940 Hood June 24, 1941 2,390,136 Trexler Dec. 4, 1945 2,707,440 Long et a1. .May 3,1955.