US3057518A - Liquid dispensing apparatus - Google Patents

Description

Oct. 9, 1962 A. L. JAPP LIQUID DIsPENsING APPARATUS Filed Nov. 25, 1959 IN V EN TOR. ,IMBERT L JPP Y ATTORNEY GOG@ United States atent 3,057,518 LHQUID DHSPENSIN G APPARATUS Albert L. Kapp, Amityville, N.Y., assignor to Gulf Oil Corporation, Pittsburgh, Pa., a corporation of Penn- Sylvania Filed Nov. 25, 1959, Ser. No. 355,318 4 Claims. (Cl. 222-459) This invention relates to a liquid dispensing apparatus and more particularly to a liquid dispensing apparatus that is adapted to deliver an accurately metered liquid at a relatively high velocity and volume per unit of time.

Liquid dispensing systems of the type designed to deliver liquids such as distillate fuel oils, that is, domestic furnace heating oils or the like, have heretofore involved withdrawing liquid from a storage tank by means of a pump, subsequent passage through an air eliminator, meter, and then through a delivery hose of relatively large cross-sectional area, at a relatively low velocity and volume ow per unit of time. Such systems have not proved entirely satisfactory because of the relatively large lamount of time consumed in effecting delivery of a given quantity of liquid, and because of the difficulty of handling the delivery hose and the liquid contained therein.

The use of lightweight, small-diameter delivery hose has been proposed but rejected for the reason that such use, under the same conditions, would increase the amount of time consumed in effecting a liquid delivery. It also has been proposed to reduce liquid delivery time by use of either the small or large-diameter delivery hose by passage of the liquid through the delivery hose at a relatively higher velocity and volume per unit of time. This has been found impractical, among other reasons, because of the high surge pressures-sucient to damage the meter-that develop when liquid ow is started or stopped. Increasing the liquid velocities and volumes in conventional delivery systems is also objectionable for the reason that relatively greater negative pressures are developed on the suction side of the pump during such operation. It is necessary to hold the negative pressure in the system to a minimum on the suction side of the pump as compared With the outside atmospheric pressure, to prevent more air being induced into the suction side of the pump and system than can be expelled by conventional air eliminators in a given interval of time when liquid is pumped through it at a relatively high velocity. This limitation on the negative pressure in the suction side of the pump and system also is necessary to prevent the possibility of metering entrained air as liquid.

It has now been found that deliveries of a liquid can be .effected at relatively high velocity and volume per unit of time with accurate metering of the liquid, even when them delivery hose is substantially smaller than the smallest cross-sectional area of any of the preceding portions of the path of liquid flow, by means of a dispensing system involving a liquid source, an air eliminator, a meter, a receiver tank, and a pump having an inlet and an outlet Iand adapted to `discharge said liquid from said outlet at a relatively high volume and at a relatively high discharge pressure, all of said elements being connected in series in the order mentioned, where the cross-sectional area of the receiver tank is substantially greater than that of the pump inlet and the uid capacity of said receiver tank is substantially greater than that of the pump, and where the meter and receiver tank are positioned at an elevation lower than the liquid source, the dimensions of the path of flow between said liquid source and said receiver tank being such that the total friction pressure loss at said relatively high volume is less than the pressure resulting from the difference in elevation between said liquid source and said receiver tank, so as to provide low velocity flow 3,057,518 Patented Oct. 9, 1962 ICC by gravity from the liquid source to the meter and receiver tank.

The receiver tank preferably is also equipped with an air venting device and is of suicient cubic capacity effectively to act as a uid baie in preventing pump cavitation with its attendant noise and vibration. Also, the meter is preferably isolated from the relatively high surge or shock pressures that develop when the liquid delivery flow is shut off by means of a reverse flow check valve positioned at the outlet side of the receiver tank.

In an especially advantageous embodiment, the pump, as well as the meter and receiver tank, is positioned at a lower elevation than the liquid source, and at the same or lower elevation than the level of the liquid in the receiver tank.

The relative capacities of all components of the dispensing system are such that the gravity ilow of accurately metered liquid to the receiver tank will be at a lower velocity and substantially higher volume per unit of time than that withdrawn by the pump from the receiver tank in an equal unit of time. When the components and system are so designed, this relationship or potential difference in volume iiowing into and out of the receiver tank will be of a magnitude that will substantially offset the effect of pump suction turbulance, thereby maintaining the receiver tank full of liquid. Hence, the meter will only measure the volume of liquid withdrawn and delivered by the pump. n

By arranging all the components having the design characteristics indicated in the sequence and at the elevations indicated, the high pressures that develop in pumping the liquid at a relatively high volume rate per unit of time through a small-diameter delivery hose will be confined to the downstream side of the receiver tank and pump, thus permitting a relatively low-velocity, high-volume flow per unit of time through the system upstream of the meter, whereby sufficient time is provided for the separation of any entrained air from the liquid prior to metering of the latter.

Referring now briefly to the drawing, the FIGURE is a schematic representation of a complete liquid dispensing system involving the principles of the present invention.

Taking up the drawing in greater detail, numerals Z, 4, 6, and 8 designate Iseparate compartments of tank 10 that is adapted to be mounted on a bed of a truck, trailer or the like, not shown. Tank 10, together with manifold chamber 20, and connecting conduits 12, 14, 16, and 18, comprise the liquid source referred to herein.

To minimize the possibility of a relatively high volume of air becoming entrained in the liquid as -the source tanks or compartments thereof become empty, or approach empty, an air eliminator and liquid 'level controller y85 is provided inthe upper portion of manifold 20. When the liquid reaches a predetermined limit or level in the manifold, float controller automatically shuts down the pump, as hereinafter described, until the ow of liquid into the manifold 20 from the source is again re-established, and the manifold 20 is lled with liquid. Any air that may have entered the manifold during this transition is evacuated by the air eliminator 85, through vent 25, thereby minimizing any excess of entrained air which would be measured as liquid as it passed through the meter because of the limitation of available devices for expelling air entrained in the liquid.

Numeral 24 designates an air eliminator or battle chamber, provided with a float controlled vent line 2'5 and connected to the outlet of manifold 20. Air eliminator 24 is adapted to facilitate removal of air or vapor from the liquid passed therethrough through float-controlled vent line 25so that the liquid may be more accurately measured by meter 26, positioned immediately downstream of air eliminator 24 and connected thereto. Numeral 30 refers to a receiver tank which is connected at its inlet to the meter 26 and its outlet to pump 36. As indicated, the cubic liquid capacity or content of receiver tank 30 is suiciently great to substantially eliminate turbulence with attendant possible cavitation at the inlet of pump 36. The receiver tank 30 also is equipped with a oatcontrolled vent line 31 to expel the air initially therein -and to prevent the accumulation of air and vapor iu the receiver tank, whereby the receiver tank will be kept full of liquid. By such means, pump cavitation, with its attendant noise and hydraulic hammer, is prevented.

In order to avoid development of relatively high Huid velocities through the air eliminator 24 and meter 26, with attendant loss of meter accuracy, the potential difference in flow of liquid by gravity through the air eliminator 24 and meter 26 should be substantially lower in velocity and greater in volume per unit of time than that being withdrawn from the receiver tank 30 in an equal interval of time and delivered by pump 36 to etlect satisfactory metering accuracy.

As illustrated by the drawing, all portions of metering and pumping sections of the system, including the air eliminator 24, meter 26, receiver tank 30, and pump 36 are positioned at an elevation lower than the lowest permissible level of the liquid supply source.

Numeral 42 refers to a conduit connecting the outlet side of pump 36 with hose reel 78 and with a suitable, small-diameter delivery hose 44. For greatest convenience, the delivery hose 44 should be substantially smaller in cross-sectional area than the smallest portion of the path of liquid flow upstream thereof. Numeral 46 indicates a delivery nozzle having7 associated therewith a manually controlled valve. Numerals 22, 28, 32, and 42 refer to conduits connecting respectively, the manifold 20 and air eliminator 24, meter 26, and receiver vessel 30 and pump 36, and hose reel 78. Numeral 34 denotes a checkvalve to prevent high shock pressures that develop when flow of liquid is shut off by nozzle 46 being transmitted to meter 26 and also prevents back flow of liquid when pump 36 is not in operation.

In operating the system, power take-off handle 50 is moved to the on position, engaging the power take-off 52 that drives the hydraulic pump 54 from the transmission of a vehicle such as a truck, not shown, on which tank may be mounted. Power take-off handle 50 also closes an electrical switch 58 for circuits 60, 62, and 64, and opens a cam-operated valve 66 which applies the brakes to the wheels ofthe aforesaid vehicle, thereby preventing any movement of the vehicle until the power takeott' is disengaged.

The hydraulic pump 54 supplies hydraulic fluid under pressure from a vented reservoir 56 through control valve 68 to hydraulic motor 70, which, in turn, drives the pump 36 by means of a direct coupling, belt or chain drive 40. Hydraulic pump 54 also supplies hydraulic power through needle valve 72 and control valve 74 to hose reel motor 76, which drives the hose reel 78.

Circuit 62, which is interlocked through relay 8G, energizes an electropneumatic cylinder 82 when switch 84 is closed, thereby moving the vehicle engine throttle, and increasing the engine speed to that required to deliver the liquid at the desired rate.

Circuit 60 is interlocked through a float-controlled switch 86 that energizes electropneumatic cylinder 38. Should a compartment of tank 10 run dry, float-controlled switch 86 will close, energizing electropneumatic cylinder 88, admitting air to the cylinder, moving control valve 68 to the ott position, and shutting down the system. No further liquid delivery can be made until another tank compartment valve is opened and the ow of liquid `from the source expels the air in manifold through vent 2S and the liquid level in the system and manifold returns to normal.

Circuit 64 is interlocked through a pressure safety control switch v that closes when pressure in the system reaches a predetermined maximum, as, for example, when the valve in nozzle 46 is closed. Closure of switch 90 energizes relay 80, causing switch 81 to close, whereby electropneumatic cylinder 88 is energized, closing valve 68 and shutting down hydraulic motor 70, and de-energizing speed controller 82, thereby reducing the engine speed to idle. When the delivery nozzle 46 is next opened, the pressure in line 42 will drop, permitting pressure control switch 90 to open, de-energizing relay 80 and energizing throttle controller 82, moving it to a high speed position for again delivering lthe liquid at the desired rate of flow.

In a specic embodiment, delivery hose 44 has an inner diameter of one inch, as opposed to conventional fuel oil delivery hose, which has an inner diameter of one and one-fourth to one and one-half inches. The weight of the smaller hose, including the liquid therein, is substantially less than that of the conventional hose. Hence the effort expended in hauling the hose out to make a delivery is, in comparison with a conventional, one and one-quarter inch I.D. hose reduced by more than 50 percent. In this embodiment, liquid is delivered through hose 44 at a rate of 75 gallons-per-minute and at a pressure of pounds per square inch, the rate of delivery of the pump in this instance, as opposed to 45 gallonsper-minute, the conventional rate through a one and onequarter inch diameter hose. ln this embodiment, a meter having an accurate flow capacity of 125 gallons-per-minute is employed. Since liquid is displaced from the system through hose 44 only at `the rate of 75 gallons-perminute, and since the potential flow rate of delivery through the meter is well above this limit, the velocity of the liquid flowing through the air eliminator is low enough to permit it to expel any entrained air in the liquid and thereby effect a high degree of metering accuracy.

It will be understood that the invention is not limited to the specific details of the pressure release system, hydraulic control system, or electrical system of the embodiment shown in the drawing. For example, instead of the pressure release valve 90, there can be employed a recirculating by-pass around pump 36, said by-pass being controlled by a spring-controlled pressure release valve.

Also, a pneumatic or electrical control system can be substituted for the hydraulic control system shown in the drawing.

Many additional variations and modifications of the invention as described and illustrated herein will occur to those skilled in the `art and such variations and modifications can be resorted to without departing from the spirit or scope of the invention. Accordingly, the invention is not to be limited by the embodiments described herein but only by the scope of the claims appended hereto.

Iclaim:

l. A liquid dispensing system comprising a liquid source, a meter, a receiver vessel, and a pump provided with an inlet and an outlet and adapted to discharge said liquid from said outlet at a relatively high volume and at a relatively high discharge pressure, said elements being connected in the order named and adapted to permit liquid flow therethrough, air eliminating means positoned upstream of said meter to remove gaseous material from the liquid prior to passage thereof into said meter, said meter and said receiver vessel being positioned at a lower elevation than said liquid source, the dimensions of the path of flow between said liquid source and said receiver vessel being such that the total friction pressure loss at said relatively high volume is less than the pressure resulting from the difference in elevation between said liquid source and said receiver vessel, so as to permit low velocity, gravity ow through said meter, said receiver vessel being provided with controlled, venting means adapted to vent the receiver vessel to the atmosphere when the liquid level in said vessel falls below a predetermined level, said receiver vessel also having a cross-sectional area and liquid capacity substantially greater than that of the pump inlet and the pump, respectively.

2. The apparatus of claim 1, wherein the pump also is at a lower elevation than the liquid source.

3. The apparatus of claim 1, where a check-Valve adapted to prevent reverse flow of liquid is positioned intermediately of the pump and the meter.

4. The apparatus of claim 1, where the liquid source is provided with a manifold chamber, and where said manifold chamber is provided with a liquid level control means adapted to stop `and starrt said pump when a minimum and maximum liquid level is established in said manifold chamber so as to prevent gaseous materials 6 entering said meter when liquid source Vessel approaches exhaustion, and where said liquid source is provided with a vent means adapted to permit escape of gaseous materials when the maximum liquid level is being reestablished and before said pump again withdraws liquid from said receiver vessel.

References Cited in the file of this patent UNITED STATES PATENTS 2,075,126 Marden Mar. 30, 1937 2,090,734 Piqurez Aug 24, 1937 2,292,007 Morgan Aug. 4, 1942 2,506,911 Teigler May 9, 1950 2,690,712 Foote Oct. 5, 1954 2,884,964 Tye May 5, 1959 2,916,880 Hahn Dec. 15, 1959

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