US2322568A - Scavenging pump - Google Patents

Description

' June 22, 1943. DE ANCEY 2,322,568

SCAVENGING PUMP Original Filed July 24, 1940 2 Sheets-Sheet l INVENTOR MRHLWH 222,122) BY 1 &w

. June 22, 1943.

w. H. DE LANCEY SQAVENGING PUMP Original Filed'July 24, 1940 2 Sheets-Sheet 2 INVENTOR Mum/52m ATTOR EYS Patented June 22, 1943 Search Room SCAVENGING PUMP Warren H. De Lancey, Springfield, Mass, assignor to Gilbert & Barker Manufacturing Company,

West Springfield, Mass,

Massachusetts a corporation of Original application July 24, 1940, Serial No. 347,288. Divided and this application February 24, 1941, Serial No. 380,151

1 Claim.

This invention relates to an improved scavenging pump for eliminating gases from the vent of a gas and liquid separator.

The invention, while capable of general application, has been worked out for and is particu larly suitable for use in connection with apparatus for dispensing and measuring gasoline and the like. One illustrative example of an apparatus, with which the separating means of this invention may advantageously be used, is disclosed and claimed in my application Serial No. 347,288, for United States Letters Patent, filed July 24, 1940. The present application is a division of the application just identified.

This invention has for its object the provision of a variable-capacity, positively-acting pump for drawing gases from the vent of an air separator, and means responsive to the pressure in the outlet of the pump for varying the capacity of the pump inversely to the rise of pressure,

characterized in that the outlet of the pump has a portion of restricted area therein sufiicient to pass all the air or other gases that the pump can pump when working at maximum capacity but insufficient to pass all the liquid that the pump can pump when working at said rate, whereby after the scavenged gases have been expelled and liquid enters the restricted portion, a rise of pressure occurs and the capacity of the pump is diminished.

The invention will be disclosed with reference to the accompanying drawings, in which:

Fig. 1 is a diagrammatical view of a gasoline dispensing apparatus embodying the improved scavenging pump;

Fig. 2 is a sectional elevational view, drawn to a larger scale, of a portion of the apparatus shown in Fig. 1; and

Figs. 3, 4 and are cross-sectional views taken on the lines 3-3, 44, and 55, respectively, of Fig. 2.

In these drawings, the invention is shown for illustrative purposes in connection with the gasolihe dispensingapparatus of the above-named application. Such apparatus is shown diagrammatically in Fig. 1 and will be briefly described. Liquid, such as gasoline, is drawn up from a low level storage tank l3 through a suction pipe [4 into a separator H. The tank has the usual vent l5 and pipe l4 has the usual foot valve 16. As 5 indicated in Fig. 2, liquid passes upwardly in back of a dam-like partition 18, flows over the upper edge of the latter into the separating chamber and passes downwardly to and through a fine screen I9 into a passage which leads to the intake of a metering pump 2|. Pump 2| is driven by an electric motor 22 (Fig. 1) through a belt connection 23 to a shaft 24, which through a hydraulic transmission 25-26 (Fig. 2) drives a shaft 21 that is connected to the driving shaft 28 of the pump. This driving shaft 28 also operates registering mechanism 29 of any suitable kind for indicating the quantity and/or cost of the liquid dispensed. The pump 2| discharges the liquid through a delivery conduit, herein shown as including a fixed pipe 30 and a flexible hose 3| with an optionally-interposed visible discharge indicator 32 of any suitable type. The delivery conduit terminates with a valved hose nozzle 33 of usual form, the valve of which tends to close automatically but may be opened manually by hand lever 34.

The separator includes an upper casing ll in constant communication with the lower portion ll through registering ports 35 and 35 formed respectively in casings l1 and H. In the casing I1 (Fig. 2) are the hydraulic transmission 2526 and a variable-capacity, positively-acting displacement pump 36. Pump 36 is driven continuously during each dispensing operation from shaft 24 and serves to scavenge the separator of air and the suction pipe also if necessary, whenever required. The air or mixed air and liquid or liquid removed by pump 36 is delivered through a passage 3'! into a chamber 38. This chamber (Fig. 3) has a continuously open vent passage 39 which will freely pass all the air that pump 36 can pump. However, the restricted vent offers more resistance to the outflow of liquid. Accordingly, as liquidifills chamber 38, pressure builds up therein. This pressure is made to lift a piston 40 which functions to vary the capacity of pump 36 in a manner to be later described. The discharge through vent 39 is conducted by a pipe 4| to a secondary separator 42 (Fig. 1). Separator 42 has a constantly open vent 43 to pass ofi the separated air to the atmosphere. In the base of separator 42 is an outlet connected by a pipe 45 to the suction pipe I4 for passing separated liquid back to the primary separator 11. The outlet is controlled by a valve 46 connected to a float 41 so as to open the valve when the liquid accumulates in separator 42 above a predetermined level and return liquid to the primary separator and so as to close the valve when the liquid falls below said level.

Referring now to Figs. 2 and 4, the primary separator includes two chambers 48 and 49 which are formed within the casing l1 and are disposed side by side therein. The dam l8 separates these chambers and is stopped ofi short of the top wall of casing l1 to provide the only means of communication between these chambers. The chamber 48 functions as a part of the inlet passage, constituting an extension of pipe l4 for delivering liquid into separator chamber 49 at a level substantially above the bottom thereof and at substantially reduced velocity. There is no other inlet to the separator. A wall 50 in casing l1 partitions off a part of chamber 49 to form the outlet conduit 20 which leads from the lower part of the chamber upwardly and thence outwardly at right angles to communicate with a registering inlet passage 5| in the meter-pump. Conduit is the only outlet for substantially air-free liquid. The screen I9 is preferably of very fine mesh and designed to restrain the passage of air bubbles therethrough. This screen at one end is fixed to a nut 52 which threads into an opening in a side wall of the casing 11. The screen extends transversely across chamber 49 near the lower part thereof and its other end fits into a socket formed in wall 58. Liquid from chamber 49 passes radially through this screen and thence axially thereof into passage 20, through which it rises and passes into meterpump 2|. The liquid, on entering chamber 48, is lowered in velocity to facilitate release of any air or gases entrapped therein. Such air and gases are liberated to a considerable extent as the liquid passes over the dam l8 but any air which may be carried downwardly with the liquid in chamber 49 is restrained by screen l9 from passing into the meter pump. Separation of air and liquid occurs on the suction side of the pumps 2| and 36 and thus at sub-atmospheric pressure, the better to release any air and gases that may be entrapped in the liquid. The casing I1 is liquid tight and the only openings leading into or out of it are outlet passage 28, the port 35, and the port connected to pipe l4.

The separator also includes an upper chamber 53, formed within the casing l1 which is superposed on casing l1 and suitably secured thereto as by cap screws 54. Conveniently, one end wall 55 of casing I1 is made removable to enable assembly of the parts in chamber 53, and this wall is suitably secured as by cap screws 56 to casing 11. Chamber 53 is also made liquid tightits only inlet being the registering ports and 35' and its only outlet the passage 31 which leads to control chamber 38. The inlet afforded by said ports is preferably relatively large in area as compared to the other ports in casing 11 for the purpose of getting the air into and the liquid out of the chamber 53 as rapidly as possible. For example, in case of a sudden inrush of air into chamber 48, as by exhaustion of the supply of liquid in tank l3, it is desired to get this air into chamber 53 through the registering ports 35 and 35' and at the same time allow the liquid in chamber 53 to drain back through these same ports into the underlying chamber. The more quickly that a change from liquid to air or from air to liquid in chamber 53 can be effected, the more quickly will the elements in this chamber respond and perform their intended functions.

One of such elements is the scavenging pump 36 which is of variable capacity and is intended to work at full capacity on a sudden inrush of air, such as above described, or for quick priming whenever necessary. This pump is of the positively-acting displacement type and is best shown in Fig. 4. It includes a stator body 51 having a cylindrical opening therethrough which opening is closed by end plates 58 suitably secured one to each of the end faces of the body. This stator, at a location below said opening, is fixed to a shaft 59 which is mounted to turn in a bearing 68 formed in one end wall of casing [1. Stud 59 is drilled to form the described outlet passage 31 for pump 36, such passage communicating at one end with the lower part of the space within the stator and at the other end with the chamber 38. Shaft 59 has an enlarged part 6| which abuts one end of bearing 60, the other end of which is engaged by the body 51. Mounted within the cylindrical opening in the body 51 is a cylindrical rotor 62 extending between the end plates 58. This rotor, which is suitably fixed to shaft 24, is radially slotted at angularly-spaced intervals to slidably receive a series, as six, of blades 63. Each end face of the rotor is recessed to receive an annular ring 64. These rings hold the outer edges of the blades 63 in engagement with the wall of the cylindrical opening. The end plates 58 have openings therein through which shaft 24 passes and such openings are large enough to enable the stator to be shifted, by turning shaft 59 within the necessary limits to secure the desired range of capacities. The capacity of pump 36 is varied by moving the axis of the cylindrical opening in the stator toward or away from the axis of rotor 62 and this decreases or increases, respectively, the capacity, For example, the pump 36 may have a maximum capacity of 20 gallons per minute and a minimum capacity of say 2 gallons per minute. The pump inlet 65 constantly communicates with the upper portion of chamber 53.

Referring now to Fig. 3, it will be noted that the described piston 40 has a short and depending piston rod 66, the lower end of which is pivotally connected to one end of an arm 61. The other end of this arm is fixed to the enlarged part 6| of shaft 59. The piston is mounted in a vertical cylinder 68, the upper end of which is fixed to a cap 59, suitably secured to and closing a cylindrical opening in the top wall of chamber 38. A spring 18 inside cylinder 68 acts between cap 69 and piston 48 to urge the latter downwardly and cause pump 36 to be moved into the position of maximum capacity. When chamber 38 fills with liquid, a pressure is built up therein sufficient to lift the piston and move the stator of pump 36 into its position of minimum capacity. The vent 39 is of substantially less cross-sectional area than passage 31. Hence the pressure will rise in chamber 38 whenever it fills with liquid. A passage 14 formed in the walls of chamber 38 interconnects the upper end of cylinder 68 and vent 39. The chamber 38 has a removable end wall 12 held in place as by cap screws 13, to enable access to the interior of the chamber for the assembly of the parts therein.

The drive shaft 24 for pump 36 is supported in a pair of spaced bearings 14 mounted one in plate 12 and one in the opposite wall of chamber 38. Seal rings 15 mounted on shaft 24 are pressed apart by a spring 16 to engage one with each of said bearings to prevent leakage from chamber 38 along the shaft. At its outer end shaft 24 has fixed thereto a pulley 11 to receive the driving belt 23 of motor 22.

The hydraulic clutch between shafts 24 and 21 has the function of driving the meter-pump Searcn KOOm when and only when there is liquid in the chamber 53. This chamber need not necessarily be filled with liquid but some liquid must be present and when only air. is present the shaft 21 and thus the meter pump 2| cannot be operated from shaft 24 and motor 22. This clutch is best shown in Figs. 2 and 5. The driving member 25, which is fixed to shaft 24, is constructed like the impeller of a centrifugal pump, having a series of passages 18 extending outwardly from the center to the periphery of the member and curving backwardly with respect to the direction of rotation as shown, Liquid entering at the center of member 25 enters all said passages and is thrown outwardly therefrom at high velocity. The driven member 26 which is fixed to the inner end of shaft 21, has a circular series of buckets 19 positioned to receive the liquid discharged through passages 18. The member 25 telescopes in the member 26. Liquid from chamber 53 enters through ports 80 in the circular, plate-like portion of member 26 and enters the central or eye portion of member 25 to be discharged through passages 18 into the surrounding buckets 19, whereby to turn member 26 from member 25. Cooperating with each port is a valve 8|, pivoted on a stud 82, fixed to member 26. These valves have arms 83, one on each, which extend toward one another and which are interconnected by the pin and slot connection 84, whereby to move in unison. A spring 95 interconnects the free ends of valves 8| and tends to hold them positioned as shown to provide minimum openings of ports 80. These valves respond to the speed of member 26 and move outwardly by centrifugal force to uncover the ports and admit more liquid to the impeller member 25.

The shafts 21 and 28 are interconnected in any desired way to secure the desired speed ratio. As shown, a worm 86 is fixed on shaft 21 and drives a worm gear 81 fixed on shaft 28, so that shaft 28 moves at one-tenth the speed of shaft 21. This worm and gear are enclosed in a housing 88 formed as an integral part of end wall 55.

The operation of the apparatus will next be described. Assuming that the apparatus has just been set up and the various pipes, the separator and the metering pump 2| are filled with air, the apparatus will become primed by simply starting themotor .22. The scavenging pump 36 will be immediately operated but the metering pump 2| will not start because of the absence of liquid from the upper chamber 53 of the separator. No torque can be developed between the clutch elements by air alone. The scavenging pump commences work at its maximum rate-say 20 gallons per minute-and very quickly exhausts all air from suction pipe I4, and the inlet passage 48 of the separator. Liqu d rises in said pipe and passage and eventually flows over dam l8 into separating chamber 49. Continued operation of pump 36 will remove the air from chamber 49 and then from the ports 35 and 35' and finally the chamber 53 so that liquid will rise into said chamber. As soon as liquid reaches one of the ports 80 of the hydraulic clutch, such liquid will enter the eye of the driving member 25 and be thrown out by the latter into the buckets 19 of the driven member 26. The metering pump 2| will then begin to operate provided, of course, that the valve of hose nozzle 33 is open as is necessary to initially prime the system. Operation of the metering pump will suck out all air from its inlet passages and eventually draw in liquid and subsequently expel it into the delivery conduit 3|l-3| to drive out all air therefrom. When liquid is delivered from the nozzle 33 its valve may be closed. The hydraulic clutch will then s1ip--allowing continued operation of motor 22 without the load of the metering pump which stops on closure of the nozzle valve. Slipping of the clutch occurs without causing wear of the parts and without the generation of such heat and without requiring much power from the motor.

The motor would normally be stopped as soon as priming is completed. However, before the motor is stopped liquid will have risen far enough in chamber 53 to enter the inlet of pump and be expelled through outlet conduit 31 into the enlarged portion thereof-the chamber 38. The restricted outlet 39 from this chamber readily passes all the air that pump 36 can deliver. However, it offers greater resistance to liquid. Accordingly, as liquid fills the chamber up to the level of vent 39, there will be a rise in pressure which will raise piston 40 against spring 18 and turn arm 61, shifting the stator of pump 36 in such a manner as to decrease its capacity. Such a shift immediately results in a decrease in pressure in chamber 38 because liquid is delivered thereto at a lower rate and the piston will move downward somewhat, causing an increase in the rate of pumping and an increase of pressure in chamber 38, thus raising the piston to increase the capacity of pump 36. Eventually a balance is established between the pressure of the liquid in chamber 38 and the pressure of the spring, and the pump 36 then operates steadily at a low rate, say 2 gallons per minute, unless and until conditions change. The pump 36, while operating continuously during each dispensing operation, will not consume much power because it is operating at a low rate and doesn't have to build up heavy pressures. All that is required is pressure enough to hold piston 40 raised and to lift the liquid a short distance to the separator 42, which is continuously open to the atmosphere. In separator 42, air and liquid separate by gravity action and the air passes off to the atmosphere through vent 43. The liquid accumulates in the lower part of separator 42 and is delivered from time to time whenever required, under the control of float operated valve 46. back to the separator H,

In normal periods when the apparatus is idle. the delivery conduit. the metering pump 2| and all its passages and the separator chamber 49 at least to the level of the top of dam I8) will be filled with liquid. And the upper separator chamber 53 and chamber 38 may likewise be filled with liquid. However, the piston 40 will be in its lowermost position and pump 36 wll be in readiness to operate at its maximum rate when the motor 22 is again started. When motor 22 is started, a quick evacuation of any accumulated air is effected by pump 36 which,

- as herein disclosed. has a capacity greater than pump 2|. If the chambers 53 and 38 are already filled with liquid, the stator of pump 36 will be immediately shifted to cut down its pumping rate to the minimum and pump 2| will be quantities of liquid.

Assuming that, due to a leaky foot valve I6 operated without delay to dispense measured or to vaporization in the suction pipe I4, the level of liquid has fallen so that chamber 53 and pipe M are empty. Then on starting up of motor 22, the metering pump 2| will not operate but pump 36 will operate at a high rate and quickly exhaust pipe l4, its extension 48 and the chamber 53. Re-priming of the system will be effected more quickly than it can be with the dispensing apparatus now commonly used and the metering pump will be started up with only a short delay.

In case the suction pipe is filled with gasoline vapor, these vapors will be recovered to a substantial extent because in passing through pump 36 and chamber 38 they are put under pressure in the presence of gasoline and that is the best Way to insure condensing of such vapors. It will be noted that chamber 38 cannot drain back into chamber 53 and that once this chamber is primed, there is always liquid present in the chamber to assist in the Work of condensing the fuel vapors.

Thus, the invention provides apparatus for improved air elimination always proportioned to the need. Rapid scavenging for initial priming or the clearing of a gas-filled suction line is always available and yet when there is no such need, the scavenging pump works at a low rate, using little power.

What I claim is:

A scavenging pump for eliminating gases from the vent of a gas and liquid separator, comprising, casing means affording a pump chamber with an inlet thereto and an outlet therefrom, positively-acting pumping means in said chamber, said means being shiftable to vary the rate of pumping of said means from a minimum to a maximum, said inlet adapted for connection to said vent, said outlet having a portion of restricted area sufiicient to pass all the air that said means can pump when working at its maximum rate but insuflicient to pass all the liquid that said means can pump when Working at such rate, whereby after the scavenged gases have been expelled and liquid enters the outlet 21 rise of pressure occurs in the outlet, and means responsive to said rise in pressure to shift said means to decrease its pumping rate and responsive to a decrease in pressure in said outlet to increase the pumping rate,

WARREN H. DE LANCEY.

- CERTIFICATE OF CORRECTION.

Patent No. 2,522, 568. June 22, 19h;

WARREN H. DE LANCEY.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, second column, line 11, for such read much--; line 72, strike out the words "operated without delay to dispense measured" and insert the same.

in line 70, before the word "quantities"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 27th day of July, A. D. 19%.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

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