US2280287A - Liquid dispensing apparatus - Google Patents

Description

April 21, 1942. Y w. H. DE LANcL-:Y 2,280,287

LIQUIDDISPENSING APPARATUS Filed Sep`t. 19,v 1939 4 Sheets-Sheet l H vf f 1H fz l l.

i M l l L z vf ii V l INVENTOR Chia? "ITORNE S April 21, 1942- w. H. DE LANcEY 2,280,287

` LIQUID DISPENSING APPARATUS Filed Sept. 19, 1959 4 Sheets-Sheet 2 INVENTOR A vd April- 21, 1942.

W. H. lDE: LANCEY LIQUID DISPENSING APPARATUS Filed sept. 19, 1959 I 4 Sheets-Sheet 4 lNvENToR MRREN H DEZA/iff y B vPatented Apr. 21, 11942 UNITED sTATEs PATENT. oFFl-CE azsazsz I LIQUID DISPENSING APPARATUS Warren H. De Lancey., Springfield, Mass., assignor to Gilbert a Barker Manufacturing Comv pany, West Springeld, Mass., a corporation of Massachusetts applicati@ september 19,1939, serial No. 295,595 `femm. icl; V1o3'5) This invention relates to an improved apparatus for pumping and dispensing measured quantities of motor fuels, including fox` example gasoline and other highly volatile liquid fuels.

This application is a continuation in parti of power consumption, the use of larger motors be' cause of the heavy starting torque required, and air separation which, while good, was by no means perfect. Attempts have been made in recent years to utilize centrifugal pumps in gasoline dispensers but these require priming and that has presented an obstacle, especially on account of the volatility of the liquid handled. A small, positively-acting displacement pump was provided to prime the centrifugal pump and also to carry olf the air, which was separated by centrifugal action in the centrifugal pump, to a secondary separator. pump, while capable of .carrying off a normal amount of separated air, was not able to quickly exhaust a. suction line which was full of air or vaporized fuel, and prime the pump with the necessary rapidity. One by one these centrifugal pump dispensers have appeared on the market and one by one they have partially or wholly disappeared because none was thoroughly successful for general use under all conditions. One of the big diiculties with them is due to 0perations under high atmospheric temperatures;

another is due to the trend to higher and higher arrangement, which is characterized by increased r efciency, lower power consumption,` low starting torque, smooth, rapid deliveries in non-pulsating flow, and, particularly, a far better and `more nearly perfect separation of air and uncondensed gases from the gasoline. The difficulties due to Here, the small priming,

vaporization and those due to slow priming, as in .prior dispensing apparatus using centrifugal pumps, are suiiiciently overcome in my improved apparatus so as to make it eflicient under conditions which render the prior art devices inefficient.

The invention also has for another object the provision in a dispensing apparatus for liquid fuel of a single separating chamber in which air may be separated from the liquid substantially at atmospheric pressure, such chamber having an inlet conduit for the liquid and any air that may be present therein, and a vent for the escape of the separated air together with an outlet conduit for conducting the 'air-free liquid to and through a v meter to a desired point of discharge, .said apparatus having a positively-acting displacement 4pump interposed .in the inlet conduit close to the level of the separating chamber for delivering the liquid, and any air present therein, into said chamber at substantially atmospheric pressure and a pump interposed in said outlet conduit close to the separator and fed thereby for forcing the air-free liquid to and through the meter.

The invention has for another object to pro- Y vide in a dispensing apparatus for motor fuels, a

single air-separating chamber which is freely vented to the atmosphere, and a feed pump, comprlslng a positively-acting displacement pump of large enough capacity for all the flow desired, for drawing up liquid from a low level tank and delivering it under substantially no pressure into the separator chamber, together with a centrifugal pump, which is fed by gravity from the separator chamber and forces the air-free liquid in a smooth, .non-pulsating ow to the meter and through ,the dispensing hose. the centrifugal pump also acting as an air separating means and forcing back into the separator tank any of the last traces of airv which may be carried along into the centrifugal pump, l

Other features of the invention distinguishing it from the prior art will be found in the combinations as pointed out in some of the annexed claims.

'I'he invention will be disclosed with reference `to the accompanying drawings, in which:

Fig. 1 is a diagrammatical view of a liquid dispensing apparatus embodying the invention;

Fig. 2 is a small scale elevational view, partly in section, showing the apparatus as embodied in a conventional form of casing for use in dispensing motorvfuels at service stations;

Fig. 3 is a sectional elevational view, drawn to a larger scale and showing in detail thedisplaoement pump, the centrifugal pump, the container, and the by-pass and its controlling means; and

Figs. 4, 5, 6, '1, and 8 are sectional plan views taken on the lines 4-4; 5-5; 6-6; 1-1; and 8-8; respectively, of Fig. 3.

Referring to these drawings, the apparatus as a whole is shown in diagrammatical form. in Fig. 1. This view will serve to show the various parts of the apparatus and their relative location. This apparatus, in common with those of the prior art, operates to draw up gasoline or the like from a suitable source of supply, such as an underground storage tank a, through a suction pipe b, and force it through a delivery conduit c, having interposed therein a meter d of any.

suitable type. The delivery conduit usually terminates with a flexible hose section e, having on its delivery end a valve controlled nozzle f. The valve of this nozzle closes automatically in the usual t and well-known way and may be opened manually by means of a hand lever g. An example of one nozzle construction suitable for the purpose is shown in Fig. 4 of De Lancey Patent No. 2,043,035, dated June 2, 1936. Interposed in the delivery conduit c is a valve device w. This device includes a check valve opening in the 'direction of normal flow under small pressure and closing automatically to prevent return flow. Ihe device w also includes a reverselyarranged check valve which opens to permit re- Y turn ow and provide relief for expansion of liquid in the hose, after a substantial pressure, say from to 20 pounds per square inch, has been established. An example of one valve device suitable for the purpose is shown in Fig. 2

of the Willson Patent No. 1,964,616, dated June It is usual also to interpose a sight glass ilow indicator h in the delivery conduit. The suction pipe b has the usual foot valve i, or other non-return valve, and the tank aapart only of which is shown-is vented to the atmosphere in the usua1 or any suitable way.

The apparatus, unlike those of the prior art, includes a positively-acting displacement pump lc, and a centrifugal pump l, closely coupled in a series arrangement at or n ear the same level for simultaneous operation by any suitable means such as an electric motor m. The displacement pump lc,- which has a capacity at least equal to and preferably slightly greater than the centrifugal pump l, feeds the latter through a discharge conduit n, delivering into a container o which is vented to the atmosphere by means of a pipe q. This container serves to hold a supply of fuel for the centrifugal pump and to feed the latter by gravity. The container also functions as a separator for any air or gas delivered to it by the displacement pump and the centrifugal pump also contributes to the ldesired result of allowing air-free liquid only to reach the meter d.

The apparatus is usually mounted in a casing 1 as indicated in Fig. 2, the pumps, motor and meter being suitably supported inside the casing as indicated, and the hose, nozzle and indicator h being exposed outside the casing. A register s, driven by the meter d, is mounted so that its indications are visible from outside the casing. The motor m has a control switch t, -operable from outside the casing by a lever u and suitable connections indicated in part at v.

Referring now to Fig. 3, the two pumps k and l and the container o are connected together by two main casing elements I3 and I4 into the assembly shown. The displacement pump, lo-

vboth pumps.

cated in the casing I3, lies immediately below the centrifugal pump which is located between the casings I3 and I4, and the container ol formed in casing I4, is superposed on. the centrifugal pump. Both pumps are coaxially disposed and are driven by a common shaft I5 which rises vertically through the container o and above the top wall thereof for connection through the fiexible coupling I6 to the armature shaft I1 of the motor m. The latter is suitably supported, as by the bracket I8 from the top wall of container o, as indicated.

The shaft*l I5 has a lower bearing I9, xed in the top wall of casing I3 and located between and closely adjacent to, the moving elements of This shaft also has an upper bearing 20 which is mounted in the top wall of container o for universal movement, thus enabling it to move into exact alignment with the lower bearing I9. The bearing 20 has upper and lower part-spherical surfaces 2|. The lowersurfaces 2| rest on complementary curved parts of a series of iins 22, upstanding from the base of a well 23, formed in the top wall of container o, The upper surfaces 2l are engaged by a complementary curved inner portion of a closure plate 24, secured as indicated to close the top of well 23. The bearing is thus mounted like the ball of a ball and socket joint and is self-aligning with the lower bearing I9. The well 23 contains a packing 25 saturated with lubricant. Below the bearing 20 and located in a recess in the bottom wall of well 23 is a suitable packing ring 26, held in place by and between a pair of metal cups 21, pressed into said recess.

The centrifugal pump Z is mounted at the base of the casing I4. This casing, which has substantially the shape of an inverted cup, has its lower end closed by the centrifugal pump. Such end has a counterbore 28 in which is seated the rim portion of a top plate 29 for pump l. The plate is held in place by several cap screws 30, vas indicated in Figs. 3 and '1. The plate 29 has a partly-conical surface 3| sloping inwardly and slightly upwardly toward acentral recess 32. This plate also has a central opening 33, in constant communication at the base of container o with the contents of said container and forming the inlet eye for the casing of the centrifugal pump. The lower part of vsuch pump casing is formed by the upper wall of casing I3. This wall has a flat annular portion 34 and a central cylindrical depression 35 .in the lower4 wall of which the described bearing I9 is fixed.

The casings I3 and I4 are provided with abutting flanges 36 and 31 which are suitably held together as by a series of cap screws 38. kThe inner and adjacent faces of these flanges 36 and 31 are recessed to form a volute passage 39 and a diffuser passage 40, the latter connecting the volute passage to the chamber 4I formed between y the top wall oi' casing I3 and the plate 29. The impeller of the centrifugal pump is mounted in the chamber 4I. This impeller includes a flat circular plate 42, which is integral with a central hub 43, fixed to shaft I5, and a series of upstanding blades 44 formed as shown in Fig. 4. A top plate 45 rests on top of the several blades and is suitably xed thereto, as by rivets 46, as indicated in Fig. 4. The bottom plate of the impeller has a depending hollow cylindrical hub 41 which fits into the well 35 and prevents circulation of liquid in the chamber 4I beneath the impeller and from the outlet thereof back to the inlet. Several holes 48 through the plate 42 coning a screen 68.

neet the in let of the impeller' to the well 85, thus subjecting opposite sides of the central portion of the impeller to inlet pressure and balancing such portion. The remaining and annular part of the impeller is balanced against liquid pressure as will be obvious from inspection of Fig. 3. To prevent circulation of the liquid in the chamber 4I above the impeller from the outlet ofthe impeller back to the inlet thereof, a flanged tubular part 50 is telescoped into the central inlet opening in the 'top plate 45 of the impeller. The flange 5I' of this part 59 is seated against the top wall of a circular recess, being pressed thereagainst by a plurality of spring fingers 52 (Fig.

6). These iingers may conveniently be formed as radially inward projections from a flat annular ring 53 suitably fixed, as by screws 54 to plate 29. The flange 5I is of less diameter than the recess in which'it is seated and can move ra- ,dially therein to a limited extent if necessary.

-of a down-turned passage 51, see Fig. 8, extending through the lower casing I3 and adapted for connection to the pipe c, preferably as shown in Fig. 2, whereby a trapis formed.

The displacement pump (Figs. 3 and') consists of a cylindrical rotor 58 fixed to and coaxially of shaft I5 and disposed eccentrically .ina cylindrical chamber 59.

This chamber is the container o, is formed in part in the casing 'I3 and in'part in the casing I4. This passage n leads from the discharge port 14 outwardly but in front ofthe inlet chamber 1| so that the initial part of this passage does not show in Fig. 3. It does, however, clearly show in Fig. 5. 'I'he passage n turns at right angles, as shown in Fig. 5, and then extends upwardly in casing I4, opening into the container at the side thereof (see Fig. 3). It will be noted that the crosssectional area of the passage n increases rapidly as it approaches the .container o. The sides of the outlet end of the passage diverge (Fig. 7) and the vertical dimension of such end (see Fig.

3) is much greater than the horizontal dimension of the passage n, at the point where it rises from the bottom of casing I3. As a result of this arrangement, there is a substantial reduction in the velocity of the liquid as it approaches chamcollar 19, in, which is' engaged the forked lower Yend of a lever 89.' The latter extends vertically formed in the central portion ofeasing I3 and extends upwardly from, the lower face thereof,

The blades and rotor'are substantially equal inaxial length to the axial length of chamber 59. The ends of the rotor are counterbored to freely receive rings 63, disposed one in each chamber and coaxially of the chamber 59. The rings 63- "ends on a pin BI. This pin is mounted at its ends 'in suitable slots, as indicated in Fig. 3, formed inthe lower edges of the side walls of that part of the passage n which lies in casing I4. The upper end of lever 89 is slotted to straddle a pin 82, flxed'in the lower and forked end` of an arm 83. of a bellcrank lever. The upper end of lever 80 is receivedqbe'tween the sides of the forked arm 83 and is thereby held against anyv substantial movement inthe direction of the axis of its pivot serve to hold the blades in outwardly-extended position and in contact withthe wall ofA chamber 59. The rotor is slidably keyed to shaft I5 allowing freedom for the impeller of the centrifugal pump to rise if necessary. A washer 64 iixed to the lower end of shaft I5 by a cap screw 65 acts by abutment with the rotor of the displacement pump to limit the extent to which the impeller of the centrifugal pump can rise and to so limit such rise that the impeller cannot 4rub against the top plate 29 of the centrifugal pump. The inlet to the displacement pump is shown in Fig. 5 as a vertical opening 66 formed in casing I3 and adapted for connection to suction pipeb. Such opening intersects a horizontal passage 61 formed in casing -I3 and contain- The latter is fixed in a nut 69 threaded into and closing the outer end of passage 61. The inner end of the screen is seated in a recess in a partition Wall 10 whichdivides the inlet chamber 1I from the outlet passage n. The interior of screen 68 communicates with inlet chamber 1I by way of a hole 12 inwall 10. The wall of the pump chamber 59 has an inlet port 13 and an outlet port 14 therein and communicating, respectively, with the inlet chamber 1I and the outlet passage n.

The passage n which, as first above described, connects the outlet of the displacement pump to 9|, This bellcrank -is pivoted on a pin 84, held in place as-indicated in Fig. 8 by the set screw 85. The bellcrank has a long arm 86, extending substantially horizontally into the container o and terminating with a forked portion (Fig. 8), the arms of which are pivoted, one to each of a `pair of depending lugs 81 on a float 88. When the liquid in the container rises to about the level the' container o falls and approaches theaforesaid level, the float 88 will start to move downwardly and move valve 16 toward its seat to close the passage 11 and close it when said level is reached. e

It' is important that the valve 16 move as easily a's possible so as to he actuated by the oat and provide for a quick-acting and sensitive means of controlling the liquid level in container o. To this end, the valve 16 is balanced. Opposite the valve is a piston 89, fixed to valve stem 18 and reciprocable in a cylinder 90.v The latter is formed within a nut 9| which is threaded into and closes the opening in casing I3 through which access is had for the machining of the seat of valve 16 and for the assembly of the valve and its piston. vThe valve stem 18 has an axial passage 92 therethrough, affording constant communication between the inlet chamber 1I and the outer end of cylinder 90. The inner face of piston 89 is Aequal in area'to the inner face of valve 16.

Thus, the inlet pressure is made to act equally in opposite directions on the valve. In like manner, the outlet pressure, in passage n acts equally in opposite directions on the valve, `the adjacent faces of the piston 88 and valve being of equal area. The valve 16 preferably also has a loose connection with stem 18, which enables the valvel to rock slightly on its st'em and find its own way tightly into engagement with its seat.

Inoperation, the displacement pump andcentrifugal pump work in series relation, the displacement pump lifting liquid from the storage tank and discharging its flow to the inlet of the centrifugal pump and the latter then taking up the load and forcing the liquid through the delivery line and meter to the outlet at the valved hose nozzle. The unit is thus a two-stage pump arrangement by'which the first pump boosts its load to the second pump which then takes it on further but, unlike the usual two-stage pump, the two pump units of 'the disclosed arrangement are of different types, each especially adapted to to prior practice where displacement pumps are used to do all the pumping, to provide a by-pass around the pump which opens only after the liquid `reaches a pressure in excess of the normal pressure needed for the delivery of the desired number of gallons per minute. Thus, the motor, according to prior practice, has to start up under av heavy load and the pump must build up a substantial pressure in the closed delivery line (say for example 18 pounds per square inch) before the by-pass opens. The by-pass here is float-controlled and opens easily. Actually, it will open soon after the liquid arrives at the inlet of the centrifugal pump and with such liquid at the performance of its own particular part of the work desired in the disclosed apparatus. The displacement pump, because it ispositive in action, is arranged herein to draw up air and vapor as well as liquid and will thus prime the centrifugal pump. Also, since the displacement pump has a capacity somewhat in excess of that of the centrifugal pump, the priming action, whenever it is necessary, can be accomplished quickly, as distinguished from the usual priming pumps which work continuously in parallel relation with the centrifugal pump and are of much smaller capacity than the centrifugal pump. In pumping gasoline, it sometimes happens that the gasoline in a long suction line located near the surface of the ground will vaporize to a considerable extent, especially in hot climates and in hot weather in temperate climates. Furthermore, the present commercial tendency to use increasingly higher and higher volatile motor fuel makes the vapor problem increasingly difficult to meet in dispensing apparatus, even at temperatures not ordinarily considered high. When both temperature and liquid are abnormal my improved apparatus will take care of both as it will either abnormal factor alone, and this result is one of the main purposes of my new combination. Under these conditions, or either of them, the small capacity priming pump such as used in prior art arrangements will take a long time to accomplish the priming function, whereas the displacement pump herein disclosed Will, under the same condition, prime the centrifugal pump much more rapidly.

The centrifugal pump is smooth in operation and delivers the liquid free from pulsations. It

` can be started up with the delivery line closed without the usev of much power, since the imtrifugal pump as the nal one in the series com-v bination, such a pump can be used effectively with increased advantages.

In gasoline pumps, it is common to start the motor m while the valve of nozzle f is closed and also to stop the flow by closing thenozzle valve while the motor continues to operate. On account of this practice, it is necessary according atmospheric pressure. The displacement pump discharges against substantially no back pressure and thus does not have to build up any Substantial pressure, as heretofore. Consequently, a small motor with low starting torque can be used for the purpose. For example, in the illustrated case a split-phase motor of one-quarter horse power can be used. On stopping the flow without stopping the motor m, the by-pass valve 'I6 will open immediately and allow the rotor of the displacement pump to circulate the liquid around in pump chamber 59. Very little power is required to start the pump unit or to operate it under the condition of a closed delivery line.

The ydisplacement pump is unloaded automatically, whenever the outlet of the centrifugal pump is closed, as by the closing of the valve of nozzle f. Thev closing of such outlet causes the liquid to rise in container o and raise the float and open the by-pass valve, thus unloading the displacement pump. The nozzle valve thus controls the by-pass valve 16, opening it to various degrees as the nozzle valve is moved toward 4closed position and finally fully opening the by- -pass valve when the nozzle valve is completely closed. The loading and unloading of the displacement pump are in direct proportion to the degree of opening and closing, respectively, of the nozzle valve. When there is no flow through the nozzle, the displacement pump is not under load other than the friction load and that due to the lifting of liquid from the level of the displacement pump to the level of the centrifugal pump. The displacement pump is placed under load only when there is flow through the nozzle and in direct proportion to the amount of such flow. According to prior practice, the displacement pump is loaded prior to the opening of the nozzle valve and remains loaded during the dispensing operation. At the end of the dispensing operationI the prior art displacement pump is actually placed under a still heavier load because the by-pass valve of such pump does not open, following closlng of the nozzle valve, until a pressure in excess of normal pumping pressure, say 18 pounds per square inch. Here, the pump is placed under load only when it is doing useful work. 1

The apparatus accomplishes the work of separat-ing air from the gasoline much more effectively than in any prior apparatus of which I am aware. The separation of air from the liquid occurs in the' container o. Liquid,vcontaining air, is delivered to this chamber under substantially no pressure and its velocity is substantially reduced by increasing the area of the outlet portion of passage n. The object here is to get the liquid into the container o as quietly and smoothly as possible. The plan is to avoid eddies or any disturbance of any kind in the liquid in the container. Thus, the vanes 5B in the base of the container near the inlet of the centrifugal pump, contribute to the same object by avoiding the vortex `or whirlpool, which would otherwise be formed at the inlet of the centrifugal pump. So far as possible, the liquid in the container is kept in a vcalm and quiescent condition which is favorable for air separation. Another condition," l favorable toair separation is that the chamber is under atmospheric pressure only. The vent q is always open to carry off all the air that can be'pumped by the displacement pump and without building up any pressure inthe container o. This container also has a large surface area to secure good air separation. With these three favorable conditions, separation of air from liquid proceeds in a most effective manner under the action of difference in densities. The displacement pump delivers all the air and all the liquid into the chamber o and there the liquid and air separate by gravity action under conditions which are exceptionally favorable. Most of the air is separated in this one chamber under ordinary conditions of operation. The centrifugal pump also contributes to the work of air separation and has for its part of the work the removal of the last traces of the air. The centrifugal pump has been specially designed to venable it to do its share of the separation work effectively. The bottom plate of the impeller is flat and free from any depressions in which air bubbles might lodge and be trapped. The top plate of the impeller slopes inwardly and upwardly from its outlet to its inlet end so that air bubbles, which tend to rise, will work their way inwardly so that they may escape upwardly through the inlet 33 into the overlying container o. Then the outlet of l the centrifugal pump is provided with a trap `an excellent separator. By combining with the l'.

centrifugal pump a trap, the pump even under the extreme `condition when it is entirely filled with air, such asv described, which makes it hard for air to escape from the pump, will nevertheless force such air backwardly into the container o as liquid enters the pump. Also by designing the impeller so as to avoid all traps and assist in the desired free inward movement of the air, a most effective means is provided to separate air from the liquid underthe aforesaid abnormal condition and also under thev normal conditionV for removing such last traces of air as might otherwise escape from the container o. Such f last traces of air, according to my conception, as may be in the form of very small bubbles entrained in the liquid entering the centrifugal pump, are effectively removed by the pump and passed back into container o.

What has been said about'separation` of air from the liquid applies equally well to any noncondensable gas. Such gas will be separated out in the same manner asabove described. How- 3K It has been noted that `the displacement pump is unloaded whenever lt is not needed. Vaporizau on of fuel in the suction pipe b by operation of the displacement pump can occur due to the creation of a vacuum therein. Vaporization fromV `10 this cause is minimized by unloading the pump when it is not doing useful work. And when it is loaded, as I have explained, such pump acts to help condense the vapors before they can escape through the vent.

In the normal operation, the pump unit will be started/up with the valve of nozzle f closed and the chamber o containing a substantial body of liquid so that thel centrifugal pump will be effective, the moment the valve of nozzle f is opened 20 to deliver liquid. If there is leakage Past the foot valve i or othery check valve in the suction line, the chamber'o may be drained partially or even entirely (down to the-level of inlet eye 6l), but even under such a condition the displacement 2.3 pump will be ableto replenish the liquid in chamber o before the operator has inserted the nozzle l in the tank to be served and opened the nozzle valve. Thus, the centrifugal pump will be primed and in readiness to deliver liquid as soon as the 30 nozzle valve is opened. There need be no delays because of the necessity for priming the centrifugal pump. The displacementpump, having a larger capacity than the centrifugal pump insures a substantial reserve of liquid in the chamber o :i3 and, as a matter of fact, the by-pass valve 'l5 will usually be slightly open because of this difference in capacities. This valve opens very easily because it is balanced. This sort of control of the by-pass by liquid level, as distinguished from liqio nid pressure, enables the displacementpump to be started up under an unloaded condition and a much smaller motor can be used than 4.would otherwise be possible. And when'it is loaded the arrangement provides for taking over all the work of lifting the liquid to the level of the centrifugal pump, the latter not sharing in that work at all but being merely loaded to feed the dispensing nozzle from the level of the centrifugal pump.

The pumping apparatus has been designed to :.n meet the most adverse conditions of service. In

, it as liquid fuel into the container o and in a very short time the centrifugal pump will be primed and ready for useful Work. Another bad condition is that Where the operator allows the pumping apparatus to operate after the tank has been m pumped dry. In such a case, the suction pipe b,

the displacement pump, conduit n, container o, and the centrifugal pump become lled'with air. However, when the tank is again filled with fuel, the apriaratus will in a very short time be working (3y, usefully again. The displacement pump exhausts the air from conduit b, forcinglt into container o, from which it escapes by way of the continuously open vent'pipe q which does not permit any substantial back pressure. The discharge pipe c re- ;U mainslled with liquid because ofthe valve w,

75 drawing up liquid and forcing it into container o.

The liquid passes downwardly into the centrifugal pump and the operation of that pump throws the heavy liquid outwardly, and forces the light air inwardly toward the drive shaft, where it rises upwardly to escape pipe q. In a very short time, the centrifugal pump will be primed and container o lled to the normal level and normal working conditionswill lbe reestablished. It can also happen that there is such a large leak in the suction line that the apparatus will not be able to deliver its full capacity of liquid. It will, however, work effectively, even at lowered capacity, and deliver air-free liquid to and through the meter and the dispensing hose and nozzle. vThus, the leak may be so large that the displacement pump will be pumping more air than liquid and thus the container o may be empty and the centrifugal pump partly filled with air. However, the centrifugal pump will still deliver what liquid is supplied to it and force back the air to its inlet as before. But the centrifugal pump cannot pump air through the meter to operate the latter.

In the prior art case of a centrifugal pump having a small displacement pump operating continuously under loads and in parallel with the centrifugal pump for priming and air elimination, much of the work done by the displacement pump is useless work and more power is consumed than would otherwise be necessary. For example, as soon as the centrifugal pump is fully primed, there is no more useful work left for the priming pump to perform. Yet it continues in operation, lifting liquid which is usually returned to the system to be again raised. Thus, the priming pump works against the centrifugal pump, drawing away from it some of the liquid and forcing it in a path which serves no useful purpose and at the expenditure of power which is wasted. And even where a mere priming pump is unloaded after the centrifugal pump is primed the advantages of the operations I have explained for my combination are not attained where the priming pump is working only in a by-pass. Here, in my new mode of operation, each pump has its own function in the delivery operation, one doing one partv of the work and the other the remaining part. vEach and usefully in a two-stage series arrangement which enables easy starting and minimum loss of energy when the pumps are operating while the flow is stopped.

The invention not only affords a liquid dispensing apparatus, having high operating efiiciency and low power consumption, but alsoand this is most important-a much better apparatus for separating air and other non-condensable gases from gasoline or other motor fuel than any. that have been available heretofore, so far as I am aware. The separation takes place under most favorable conditions at atmospheric pressure, kand all the work is done in the one chamber. The liquid therein is spread out over a relatively large area and forms a pump helps the other. They work cooperatively shallow pool through which air can rise easily and rapidly.l The prior art separators used in gasoline dispensers commonly utilize two separating chambers, in the rst of which separation takes place under substantial pressure which retards separation, and in the second of which the final separation takes place at atmospheric pressure so as to return entrained liquid to the ilow system from the air separation by-passes` From the first chamber in the prior art a1'- rangements in general use, liquid as well as air leaves through a restricted vent into the second separator. From the second separator liquid must be returned to the system and pumped up again. In the present case, the air separation is accomplished Without diverting any liquid from the main stream of liquid. There is no secondary stream. No liquid leaves through the vent pipe. The result is an exceptionally thorough separation of air in the container o and this highly efiicient separation is supplemented by the action of the centrifugal pump which removes the last traces' of air, allowing air-free liquid only to pass to the meter and be dispensed.

What I claim is:

Separating apparatus for removing air from liquid motor fuel in dispensing systems, comprising, casing means having a single air separating chamber vented near the upper part thereof to the atmosphere, a'centrifugal pump chamber immediately below the separating chamber and having its inlet extending through the lower wall and opening directly into the base of the separating chamber, and a displacement pump chamber also below but close to the separating chamber and to the first pump chamber; a cen.

trifugal pump impeller mounted in the first pump chamber, a positively-acting displacement pump rotor mounted in the second pump chamber, a common power shaft for driving said impeller and rotor, said casing means having inlet and outlet passages for the displacement pump, said inlet passage adapted for direct connection to a supply tank of said fuel, said outlet passage leading directly into said separating chamber, said casing means having an outlet passage for the centrifugal pump, the displacement pump having a capacity at least as great as the centrifugal pump; said displacement pump sucking up the liquid and/or air and fuel vapor from the supply tank. compressing any vapor to liquefy it and pushing the liquid and/or air into the separating chamber under substantially no pressure', whereby the liquid in the separating chamber is maintained substantially quiescent and at substantially atmospheric pressure to enable effective separation of the air, said centrifugal pump taking liquid directly from said separator chamber under substantially no pressure and forcing such liquid through its outlet, said ccntrifugal pump also preventing the passage of air and forcing it to rise through the liquid in the separating chamber and out through said vent.

WARREN H; DE LANCEY.

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