US2134686A

US2134686A - Pumping apparatus

Info

Publication number: US2134686A
Application number: US59254A
Authority: US
Inventors: Lancey Warren H De
Original assignee: Gilbert and Barker Manufacturing Co Inc
Current assignee: Gilbarco Inc
Priority date: 1936-01-15
Filing date: 1936-01-15
Publication date: 1938-11-01
Anticipated expiration: 1955-11-01

Description

Nov. 1, 1938. w. H. DE LANCEY PUMPING APPARATUS Fi'led Jan. 15, 1956 5 Sheets-Sheet 1 V! M M f 6 I 1 a J J m f. z J m%. W J 7 f 6 4 6 v f 3 3 3 6 N 0 g s EJW l l l l l l l l lflfl lfl r V N l l ll ln l ll l ll l ll J Nov. 1, 1938. w. H. DE LANCEY 2,134,686

PUMPING APPARATUS Filed Jan. 15, 1936 5 Sheets-Sheet 2 TTORNEYS Nov. 1, 1938. w. H. DE LANCEY 2,134,686

PUMPING APPARATUS Filed Jan. 15, 1936 5 Sheets-Sheet 3 INVENTOR W V 7144/, ATTORNEYS 8- w. H. DE LANCEY 2,134,636

v PUMPING APPARATUS Filed Jan. 15, 1936 5 Sheets-Sheet 4 lzpa 0 0 INVENTOR Mm 1K0: ZA/mrr *yzdl ATTORNEYS Nov.

l, 1938. w. H. DE LANCE Y PUMPING" APPARATUS Filed Jan. 15, 1936 mo 94 9f 64 5 Sheets-Sheet 5 Patented Nov. 1, 1938 PUMPING APPARATUS Warren H. De Lancey, West Springfield, Mara, asaignor to Gilbert 8a Barker Manufacturing Company, West Springfield, Maaa, a corporation of Massachusetts Application January 15, 1936, Serial No. 59,254 1 Claims. (01. 108-113) This invention relates to improvements in apparatus for pumping relatively volatile liquids, such for example as gasoline. The pumping apparatus has been particularly designed to meet the special conditions which are encountered in dispensing accurately measured units of gasoline and, while capable of other adaptations, is especially suitable for the particular use described.

The invention seeks to utilize in dispensing apparatus of this class, the well-recognized advantages which the centrifugal type pump has over the displacement type pump which at present is the type most widely used in such dispensing apparatus. The centrifugal pump is smoother and more quiet in operation; will deliver the required quantity of liquid in a minimum of time; consumes less power; enables substantial savings in manufacturing costs; and is less likely to require servicing. In addition, this type of pump can readily be utilized to secure through the centrifugal action of the pump itself, a very eflicient separation of air from the pumped liquid and a small displacement pump, necessary for priming the centrifugal pump, can be made to perform the additional function of scavenging the separated air.

This invention has for one object to provide in a pumping apparatus for gasoline or the like, having a centrifugal pump designed to pump the liquid and also cause, through its centrifugal action, a separation of air from the liquid and a displacement pump for priming the centrifugal pump and scavenging the separated air, an effective means to insure that the air-free liquid discharged from the centrifugal pump maintains its air-free appearance when delivered to the customer.

With the forms of centrifugal pumps heretofore proposed for use in gasoline dispensers, it can and does happen at certain times and under certain conditions, that the gasoline will become partially vaporized in the discharge chamber or passages of the centrifugal pump and, when this occurs, the liquid discharged has a foamyappearance due to the presence of innumerable small bubbles of gasoline vapor. The air-free liquid does not actually appear so and the customer naturally objects. It is not enough to free the gasoline from air but it must also be delivered to the customer in clear condition with an air-free appearance and this is efiected by my invention.

The invention also has for an object to provide, in an apparatus of the class described, an

improved structural combination for pumping' gasoline or the like and for effecting the separation of air from the liquid and the scavenging of the separated air.

The invention has many other objects, relating to improvements in the structure and in the arrangement of parts in a motor-driven pumping unit of the class described, and these will best appear as the detailed description proceeds.

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

Fig. 1 is a. small scale elevational view of a gasoline dispensing apparatus embodying the invention, certain parts of the casing of the apparatus being broken away to reveal interior mechanism;

Fig. 2 is a fragmentary elevational view taken at right angles to Fig. 1;

Fig. 3 is a sectional elevational view showing in full detail the liquid recovery device used in connection with the air separating means of the apparatus;

Fig. 4 is an elevational view of the motordriven pumping unit, drawn to a larger scale,- the lower and pump portion of the unit being shown in section;

Figs. 5, 6,7, 8 and 9 are sectional plan views taken respectively on the lines 5-5, 6-4, 1--'|, 8-8 and 9-9 of Fig. 4;

Fig. 10 is a fragmentary cross sectional view taken on the line Ill-40 of Fig. 9;

Fig. 11 is a sectional plan view showing a modification in the shape of the inlet port of the displacement pump;

Fig. 12 is a fragmentary sectional view, taken similarly to Fig. 4 and showing a detail of the centrifugal pump;

Fig. 13 is a fragmentary sectional elevational view, taken similarly to Fig. 4, and showing a modification in the centrifugal pump construction; and

Fig. 14 is a sectional plan view taken on the line l4-l4 of Fig. 13.

Referring to these drawings; the invention is shown in Fig. 1 embodied in a gasoline dispensing apparatus of the so-called meter type. The apparatus, therein illustrated in more or less conventional form, is intended to show the usual environment in which the invention is used, and will serve as an illustrative example of one of many types of such apparatus with which the invention may be used.

As shown in Fig. 1, the apparatus is for the most part contained within a casing l5, having upstanding column-like corner portions it from which most of the parts are supported. This casing is closed at the top by a cap l1 which usually carries an ornamental globe it. The pumping unit, shown separately in Fig. 4, is mounted near the lower part of the casing, resting on a plate is which is secured to the portions II. The unit is fixed to said plate by bolts 20. This unit includes an electric motor II, on the upper end plate 22 of which is formed a box 23. This box houses the usual control switch which has an operating lever 24. The switch may be operated by a lever 26, located outside casing II and flxed to a shaft 26 which extends inside the casing and carries an arm 21, connected by a link 20 to lever 24. The part2! is a fltting for connection to a conduit through which the electric wires are led to the motor. This part 22' is connected to the casing 22 by a screw 2} on which the part 22' may swivel.

The motor-driven pumping unit draws gasoline up from an underground supply tank (not shown) through a suction pipe shown in part at 29, and in the suction pipe is theusual check valve which prevents downward or return flow. Gasoline is discharged from the pumping unit through a pipe 30 which is connected to the inlet of a meter ii. The meter may be of any suitable type and has associated therewith any suitable form of registering means, herein conventionally indicated at II, which are driven from the meter by a shaft 33. The gasoline leaves the meter by way of a pipe 34 which'extends through the casing I 6 for connection to a flexible hose I6, having at its delivery end a hose nozzle 36, equipped with a normally closed valve which can be manually opened by a lever 31. This nozzle is of the same general type as is shown in U. 8. Patent No. 1,870,918, granted August 9, 1932, on an invention of Joseph A. Logan and may, and preferably does, have the outwardly opening check valve shown in said patent. Usually and as shown herein, there is interposed between pipe 34 and hose 36, a visible discharge indicator 38 of any suitable form. When the apparatus is not in use, the nozzle 36 is hung up on a support 39 (see also Fig. 2) flxed to and projecting outwardly from casing I and when thus hung up, movement of the switch lever 26 in the direction necessary to start motor II is prevented by abutment with the nozzle, as i will be clear from Fig. 2. When the nozzle is removed from its support, lever 25 may be swung in a clockwise direction into vertical position to start the motor.

The pumping unit has provisions for separating from the gasoline any air that may be passed up pipe 29 and such air, and usually some gasoline with it, is expelled through a pipe 40 which leads upwardly to a tank-like device 4|. This device, as shown in Fig. 3, affords within it a chamber 44 into the upper part of which the air and gasoline is delivered. In this chamber the gasoline and air are gravitationally separated and the air passes out to the atmosphere. In detail, the air leaves through ports 45 formed in the upper wall of chamber 44, passing into an overlying float chamber 46, from which the air escapes through an outlet 41 in the top wall of such chamber. A cap 49 covers outlet 41 and contains a screen 46 through which the air must pass to reach the outlet 49' of cap 49. The outlet 41 can be closed by a valve 60 fixed to a float ii in chamber 46, if and when necessary because of some unusual and abnormal condition, to prevent gasoline from passing out wardly and is -The pipes 29, 30'

arsao'so' through the outlet. The gasoline accumulating in chamber 44, eventually raises a float 52 which is mounted to slide on a guide rod 63 fixed to the lower wall of chamber 44. The rising float 52 operates through a lever 64, pivoted at 55 to raise a valve 66 and allow gasoline to enter a pipe 61 which, as shown in Fig. 1, extends downconnected to suction pipe 29. Valve 66 opens from time to time as necessary to prevent undue accumulation of gasoline in chamber 44 and closes before all the gasoline in the chamber is exhausted so that air cannot pass back through pipe 51 to the suction pipe 29.

The apparatus, thus far described, will serve as one illustrative example of the general class with which the invention may be used. The invention is more particularly concerned with the pumping unit, wherefore it follows that the details of the apparatus described are not essential and that the invention is not limited thereto.

The pumping unit is best shown in Fig. 4. This unit, as already described, is driven by an electric motor 2i, having the end plate 22 and another and specially-formed end plate 58,-such plates being suitably held together as by a series of tie rods 69. These rods are threaded into lugs on the upper end plate and slldably fit and pass through corresponding lugs 60 on the lower end plate. Nuts 6i, threaded on the lower ends of rods it, serve to clamp the head 58 in place and also enable its convenient removal from the rest of the motor whenever necessary or desired.

This end plate 58 is hollow cylindrical in form, closed at its lower end by a wall 62, from which upstands in concentrical relation a hub-like portion 63 of stepped cylindrical formation. This portion 63 is connected to the cylindrical wall by a series of radial ribs 64 (Fig. 9) arranged in angularly spaced relation. The plate 58 at its lower end has an annular flange 65, resting upon a corresponding flange 66 formed on a lower casing member 61. It also has a cylindrical flange 66 fitted into a corresponding recess in the lower casing 61. A gasket 69 is interposed between

flanges

65 and 66 and a gasket is interposed between the end face of flange 68 and the lower wall of the recess into which it fits. The two

flanges

65 and 66 are clamped together, with the gaskets between them to seal the joints, by a series of angularly spaced bolts 1i (Fig. 9). The flange 66 has a series (four as shown in Fig. 5) of lugs 12 projecting outwardly beyond the overlying flange 66 to receive the bolts 20', heretofore described as securing the pumping unit to its supporting means I 9. It will thus be seen that the lower casing 61 only is bolted to such supporting means IS. The bolts 1i may be removed to enable removal of the lower head 56 and other parts later to be described, without removing the bolts 20, thereby leaving the lower casing tightly bolted in place.

and 40, being all the pipe connections to the pumping unit, connect with the lower casing. Thus, the pumping unit, including the motor and all parts driven therefrom and all parts housed in end plate 58, may be removed without breaking any pipe connections.

The lower casing 61 is formed to provide a central boss 13, into which the suction pipe 29 is threaded and in which is a cylindrical passage 14, the upper end of which converges into an opening of smaller diameter, forming the inlet eye of the centrifugal pump. Casing 61 is also formed to provide a discharge chamber 16 of annular form, encompassing the boss 13 and connected the motor including arseoee,

thereto by a circular top wall 11 which extends part way across the upper end of chamber 18 in overhanging relation and through which the opening I extends. The casing 81 is also formed with an outlet I8 (Fig. 10) for chamber 19 and into this outlet pipe 38 isthreaded. The lower wall 82 of end plate, 58 and the top wall ll of the lower casing together form the housing of a centrifugal pump and are suitably recessed as shown, to form a pump-chamber 19. This chamber diminishes in height from a maximum near the central opening to a minimum at its outer peripheral partwhere it converges to a very narrow outlet slot 88. This slot, which forms a diffuser, extends entirely around the chamber and communicates with the underlying outlet chamber I8 by a downwardly curving slot M which diverges in the direction of liquid flow. In the chamber 19 is located the impel1er82 of a centrifugal pump. The construction of this impeller is such that it may be, and preferably is formed by die casting. As shown, the impeller is of the open type. It has a central hub 83 keyed to the lower end of the armature shaft 88 of motor 2| and clamped against a shoulder 85 on said shaft by a nut 86. Integral with the hub 83 is a disc 81 having a fiat upper face and a lower face of frusto-conical form. Depending from this lower face are a series of angularly-spaced impeller vanes 88 the inner ends of which are spaced from hub 83. Formed in disc 81 between the inner ends of vanes 88 and hub 83 are a series of vertical holes 89. These holes enable fluids, including all the air and gases in or with the volatile liquid and normally also some of the liquid itself, to passvertically upward to an overlying displacement pump. These holes 89 open into a central area above the impeller, which area is partitioned off from the remaining area by an upstanding annular flange or collar 89' formed on the impeller.

The displacement pump is desirably located immediately above the centrifugal pump in a cylindrical chamber 98 formed in the lower portion of hub 83 and opening into the aforesaid central area of the chamber I9 of the centrifugal pump. While various forms of displacement pumps may be used for the purpose, it is preferred to use the particular form of pump shown in Fig. 7. Such pump comprises a pinion gear 9|, keyed to the shaft 88 of motor 2 I, and an annular gear 92, rotating about an axis 93, eccentric to shaft 88. The annular gear turns in a cylindrical recess formed in a center plate 98 concentric with axis 93. Plate 98 is clamped between two

end plates

95 and 98 through which shaft 88 passes with ample clearance, as indicated. The provision of this clearance is for the purpose of avoiding the wear on the shaft 98 which would otherwise occur if it made contact with these plates which, because of the nature of the pump, have to be hardened and lapped to engage with an exceedingly close fit the end faces of the gears 9| and 92. A series of cap screws 91 pass through the

plates

98, 95 and 96 and thread into hub 63 to fasten the displacement pump in place. In addition, other screws 91' pass through

plates

96 and 98 and thread into plate 95 to clamp the plates together and maintain the parts of the displacement pump in assembled relation when the screws 91 are removed. The plate 95 is formed with an outlet port 98 of the form shown in Figs. 4 and 6 and the plate 96 is formed with an inlet port 99 of the form shown in Figs. 4 and 8. The plate 96 is recessed to rotatably receive the flange 89' (see Fig. 12 where this arrangement has been separately shown to avoid confusion in Fig. 4). The inlet port 89 lies inside this groove and flange and directly communicates with said central area. Particularly, the port 99 directly overlies the impeller 82 of .the centrifugal pump at a radial location which is close enough to the axis thereof to receive all the air and gases collected in the suction pipe as will appear. The outlet port 98 communicates with an overlying recess I88, formed in hub 83 and from which a passage I8I extends radially outward through one of the webs 88 (Figs. 4 and 9) to the periphery of end plate 58,-the outer end of this passage being closed by a plug I82. Communicating at one end with passage IIII is a passage I83 which extends downwardly to and through flange '65 and registers with a passage I88 which extends from the upper surface of flange 86 downwardly to a lateral outlet passage I85, formed in the base member 61 and connnected to the described pipe 88.

The innner rotor 9| of the displacement pump is driven in the direction of the arrow shown in. Fig. 7 by the motor on the shaft 98 of which it is mounted. The rotor 9| in turn rotates the outer and annular rotor about the axis 93. The inner rotor has one less tooth than the outer rotor and the contours of the teeth and the spaces between them are designed so that the teeth of each continuously slide in close contact over the contour of the other. In the priming pump the teeth of one rotor are generated by the teeth of the other rotor. The two rotors present a series of closed pockets I88 which gradually expand in volume as the rotors turn from the full mesh position I81 to the open mesh position I81 and then gradually contract in volume, as the rotors turn from the last named position back to the position I81. I prefer to make this displacement pump according to the principles of rotor construction used in either of the Hill Patents No. 1,682,564 and No. 1,682,565 of Aug. 28, 1928. During part of the time while these pockets are expanding in volume they communicate with the inlet port99 and thus, due to the suction created by the increase in volume of these pockets, fluid is drawn up through the port 99 to fill the pockets. Then each pocket becomes successively cut off from port 99 and shortly after moves into position where it can communicate with outlet port 98. Then as the pockets I86 gradually decrease in volume, the fluid is expressed through the port 98 into the outlet passages above described.

A modification in the shape of the inlet port is shown in Fig. 11 at 99. The boundary walls of this port, instead of being vertical are inclined to v energy of the fluid is to some degree utilized to cause it to enter the inlet port 99' rather than relying solely on the partial vacuum created by the displacement pump.

Above the displacement pump, the hub 83 is bored out to receive an anti-friction bearing. Because of the exceedingly close clearances between the rotors of the displacement pump, it is essential that the motor shaft 88 be held in very close alignment. An ordinary sleeve bearing such as is ordinarily supplied in electric motors would not sumce because the usual clearance of one to two thousandths of an inch would allow too great an eccentricity of movement of the shaft for the closely interfitting rotors. By preference, of the various forms of bearings available, a ball bearing having the inner and outer races I88 and I 89 with intervening balls III, is employed to secure a mounting of the shaft which will hold it with the close degree of accuracy required in the intended alignment. For similar reasons, the displacement pump is located as closely as possible to the bearing and the impeller of the centrifugal pump is located as closely as possible to the displacement pump. The overhang of the shaft below the bearing is made as short as is feasible to avoid the possibility of any eccentric movement of the shaft due to whipping or centrifugal action.

Actually, the bearing and the displacement pump are spaced because of the necessity of providing a sealing means to prevent escape of gasoline from the displacement pump around the shaft 84. Such means is mounted in a cylindrical chamber III, formed within a tube II2 which extends between plate I4 and the race I. The sealing means comprises a cup-shaped metallic member III having an opening in itsend face through which shaft 24 passes, and within the cup portion a packing washer II4 tightly fitting the shaft. A spring Ill acting between the race I" and the washer II4, presses the latter against the bottom of the cup and presses the .outer end face. of the cup against the lapped upper face of pump plate I. The cup III is caused to turn with shaft 44 because of the frictional engagement of the washer with both cup and shaft. The spring I ll turns with shaft 24 since it presses at one end against the race IIII which-is fixed on the shaft, and at the other end against washer II4 which also is fixed to the shaft.

The chamber which houses the sealing means is vented by a radial passage II! formed in one of the radial webs 84 and extending from tube 2 outward to the periphery of end plate II for communication with the atmosphere. An annular groove I I1 is formed in the outer periphery of tube H2 and communIcates with passage IItand a plurality of radial holes III are provided in the tube to enable'oommunication between its interior and groove III. This venting means provides an easy path for the escape of inflammable vapors should any such leak from the displacement pump. Except for this means, the vapor might, in the event of leakage, creep along the shaft, entering the casing ofmotor 2I and the housing 22' of the motor switch, and be exploded by an electric are from the switch.

Above the ball bearing described, there is a portion 9 formed on the upper part of hub 63 and such portion appearslike an ordinary sleeve bearing, encompassing the shaft with a fit comparable to that used in a sleeve bearing. This portion II. is provided as a safeguard in the event that an explosion should occur inside the motor casing. The purpose of portion I I! is to prevent flame from penetrating into the displacement pump and causing an explosion there. The portion II 2 thus serves as a fiame arrester and not in any sense as a bearing for shaft 04.

The motor 2I may have both bearings for shaft 04 constructed as described. It is not, however, essential that the upper bearing be so constructed. That is. a small radial play between the shaft and upper bearing of an amount within the usual tolerances of a sleeve bearing will cause no difficulty. The small play in the upper bearing results in a greatly reduced play of the shaft at the point where the rotor OI is attached to it because the length of the shaft between the bearings is several times the length of the shaft between the lower bearing and rotor 2|.

It is not essential that the diffuser for the cen-' are machined to receive the ansasse trifugal pump be of the particular form shown, viz., the two closely spaced annular walls with the narrow slot ll therebetween. Instead of that type of diffuser, I may use any other suitable type such, for example, as that shown in Figs. 13 and 14. The diifuser in this case comprises a circular series of angularly spaced vanes I20, surrounding the impeller and mounted between the upper and lower vertically-spaced parallel walls I M and I22, being fixed to or integral with one of-such walls. These walls, it will be noted, are more widely spaced than the corresponding walls in Fig.4. This enables a substantial reduction in the friction loss to be effected. These vanes I afi'ord between them specially shaped passages I23 which gradually enlarge in the direction of the flow of liquid through them and which function to gradually reduce the velocity of the-liquid leaving the impeller and to efllciently transform the kinetic energy of the liquid into pressure energy. This form of diffuser, like the former, avoids the dissipation ineddies of the kinetic energy of the liquid and avoids cavitation, but .it accomplishes these results with less of a friction loss.

This form of difi'user is, however, not widely used for relatively small centrifugal pumps because it is difiicult and expensive to accurately form and finish the vanes, which due to space limitations have to be very small. These disadvantages, I overcome by forming the vanes by die casting. The vanes are integral parts of a removable plate secured to one or the other of the

castings

58 or 81. While these

castings

58 or 61 do not lend themselves to manufacture by die casting, a small section such as shown in Figs. 13 and 14; may readily be die cast. In this case, I have provided two die cast plates I24 and I2! which line the inner, and confronting faces of the castings 58 and i1 and which are suitably held thereto as by screws I26 and I21, respectively. The plate I24 carries the vanes I20. These plates between them form the walls of the pump chamber It, the walls HI and I22, the diffuser with its vanes I20 and intervening passages I22 and the outlet passage OI. All the surfaces of these elements may be formed with close accuracy by die casting, thus eliminating much expensive machining. The

castings

58 and 61 plates I24 and I25, respectively, but the machining required is simply plain facing and boring. The difficult surfaces to machine, including the curved surfaces and the tapered surfaces, are formed accurately and at low'cost by die casting. As heretofore noted, the impeller also may be formed by die casting. Aside from the saving in cost, which is important, all the surfaces exposed to the liquid are formed with a smooth and polished finish, which results in a material reduction of the' friction loss and a material increase in the efficiency of the pump. To secure polished surfaces formed with close accuracy, with the construction shown in Fig. 4, would require a large amount of time and expert hand labor.

The operation of the apparatus will now be described. The actual dispensing operation is accomplished in the usual way. The operator removes nozzle 28 from support 39, moves lever 25 in a clockwise direction (Fig. l) to close the switch of motor 2I and thus start the pump in operation. He then inserts the nozzle in the tank to be. filled and controls the flow with the nozzle valve, closing it when the register 32 of the meter shows that the desired quantity has drawn up in suction pipe 29 far enough to reach the impeller blades 88.

' its support and moves lever to stop the motor.

When the apparatus is first installed, it will a be necessary to drive all air out of the system and this is accomplished by operation of the pumping unit with 'the valve of nozzle 88 held open. The displacement pump alone first functions in this operation, pumping out air and discharging it through pipe 48 to chamber 44 and then to the atmosphere until liquid has been Then the centrifugal pump becomes active and forces liquid up pipe 88, driving the air ahead of it until the meter 3|, pipe 34, indicator 36 and the hose are entirely filled with liquid. Then the valve of nozzle 88 is closed and the system is ready for the normal operation. I

Once the system is thus filled, this air-elimihating operation will not ordinarily need to be repeated. The foot valve or check valve associated with the suction pipe 29 will, if it closes tightly, maintain the pipe fllled with liquid and the centrifugal pump primed. However, if and when this valve leaks, making priming of the centrifugal pump necessary, the work will be accomplished quickly and automatically by the displacement pump with a minimum of effort. This follows because the system on the discharge side of the centrifugal pump remains completely fllled with liquid. The discharge chamber 18 of the centrifugal pump is below the level of the chamber 19 of that pump and consequently liquid does not drain back from the discharge side of the pump to the suction pipe 29,--the nozzle 38 being closed and there being no other way for'air to enter the discharge line. Thus, when priming of the centrifugal pump is required, it is only necessary to 'exhaust the air from the chamber 19 of that pump and from the suction pipe 29. This is an important feature because it enables the priming, to be quickly accomplished. It would be much slower if air had also to be exhausted from the discharge line because the air expands during the exhausting process and it takes a long time to remove it all. If the system could completely drain, one would be obliged to repeat the operation used when the pump was first installed, and continual adjust- .der to avoid making such adjustments or corrections, to keep the discharge side of the system completely filled with air-free liquid.

In the normal operation, on the closing of the switch of motor 2|, both pumps are simultaneously setin operation and, if the impeller blades 88 are submerged in liquid, the centrifugal pump immediately begins its work. If not, the operation of the displacementpump will soon raise liquid to the elevation necessary for the purpose. The centrifugal pump not only supplies the necessary pressure to force the liquid through the discharge pipe, meter, hose and nozzle, but it also enables a very eflicient separation of air and gases from the liquid to be effected under all conditions, irrespective of the amount of air and the viscosity of the liquid. The air-separating function takes place in the following manner. The impeller blades 88 whirl the liquid at a' very rapid rate (say for, example 3500 R. P. M.) and this whirling of the liquid extends far down into. the suction pipe. This pipe, at least at its inlet to the centrifugal pump,

is directed axially toward the same and in a manner such as to enable the whirling effect of that pump to be carried down into the suction pipe and form a vortex. The liquid, being heavier, is thrown outwardly while the air is .forced radially inward toward the center of the vortex. The displacement pump scavenges this vortex, removing air and gases therefrom, whenever present, and with them some liquid and at other times liquid only, and discharging the same to the liquid recovery chamber 44. Here the air escapes to the atmosphere and the liqfuid is collected and returned from time to time,

by way of pipe 51 to the suction pipe. The holes 89 enable the air and gases which cling as closely as possible to the hub 83 of the impeller, to rise directly into the overlying inlet port 89 of the displacement pump. This path of escape isthus the direct and natural one for air and gases which tend to rise. At'the same time, the annular flange 88' which is preferably employed as described, prevents any possibility of a circulation of liquid around the impeller, as from the tips of blades 88 over the top of the plate 81 to holes 89 and thence downwardly to the inner ends of the blades 88. Such a circulation, involving as it does passage of fluid through holes 89 in a direction opposed to the planned direction of air flow through these holes, would interfere withthe smooth operation of the displacement pump in its work of air removal. As it is, there are two separate and natural paths, one for liquid to the impeller blades of the centrifugal pump and one for air and gases to the rotors of the displacement pump. Since the latter has a capacity great enough to remove all air from suction pipe 29, it will naturally be more than suflicientto; remove all the air and gases that travel up pipe 29 in or with the liquid, in the normal operation of the apparatus. Air and gases will thus be held within the central area of the impeller inside its blades and be kept from reaching ,said blades and passing to the discharge line and meter. Thus air-free liquid only can reach the meter.

Actually, considerable liquid will be discharged by the displacement pump and later returned to the suction pipe. However, little energy is required for this work because the pressure developed by the displacement pump is only that small amount necessary to raise the fluids the small distance to the chamber 44 which is always vented to the atmosphere. Heretofore, where separation has been accomplished in an accessory device, it has been necessary to raise all the liquid which is by-passed through the separator back to the suction line, to a substantial pressure-usually to the operating pressure of the pump (generally at least 15 lbs. per sq. in.) This requires considerable work and represents a substantial waste of energy. In some cases, as much as 15 per cent of the pump liquid, which has been raised to the heavy operating pressure, is by-passed back to the suction line. In the present case, a substantially less volume, say 10 per cent, is thus by-passed but none of this liquid is raised to the operating pressure of the pump nor indeed to any appreciable pressure at all. So the work of the displacement pump does not consume much energy.

The plan of air separation described does not require for its success any back pressure, as does the ordinary air separator used in gasoline dispensing systems as an. accessory. In such systems, a check valve, usually opening only after at least five pounds pressure has been built up at the hose nozzle II, is used. The use of such a valve means that additional pressure must be built up by the pump and more power con- 5 sumed in doing it. Actually, no such valve is required for the air separating function described. It is simply necessary to whirl the liquid by the centrifugal pump and allow the vortex to form as described. However, to prevent draining of the hose when the apparatus is not in use, I use some sort of a valve at the nozzle 36 which valve can only be opened when pressure exists there but the pressure may be much less than that usually employed. And by reducing the back pressure due to this nozzle valve, the operating pressure can be reduced by the same amount and a substantialsaving, around 20 per cent, made in the size of the motor and the power consumed. A smaller and thus cheaper motor may be used than can be in the usual meter-type gasoline dispensing apparatus, assuming equal volume of delivery in a given time in each case.

The centrifugal pump is utilized solely for pumping the liquid to be measured and then dispensed. No part of this liquid, which has to be raised to a substantial pressure, is returned to the suction line, as is usual. Thus, less power is required to operate it. Also, the motor 2| need not have a high starting torque as is necessary where displacement pumps are used. The centrifugal pump builds up pressure gradually although in ample time for the purpose,that is in the interval during which the operator, after having removed nozzle 36 from its support I! and turned on the motor switch, carries the nozzle to the tank to be filled. The particular type of centrifugal pump illustrated has the advantage of maintaining a substantially uniform pressure, irrespective of the rate of liquid delivery, over a considerable range. Unlike other pumps of this general class, the pressure does not fall oi! sharply as the rate of delivery of liquid increases. For example, with the present pump, the pressure remains substantially constant for all rates of delivery up to 16 gallons per minute. Another advantage of the centrifugal pump is that no by-pass valve need be used with it to prevent building up excessive pressures in the discharge line when the pump is operated, as it often is, while the valve of the hose nozzle 36 is closed. At such times, the impeller of the centrifugal pump simply churns the liquid around in the pump chamber 19.

The particular type of centrifugal pump illustrated has a special advantage in a dispensing apparatus for gasoline and other relatively volatile liquids. It is not enough merely to pump the gasoline in the same way that water or other less volatile liquids are pumped bymfugal pumps of ordinary form. For the special use described, the pump must be designed to avoid cavitation and the formation of eddies in the discharge chamber. Without a suitable difiuser cavitation can occur there and the liquid leaving the impeller will whirl around at high veloc- "ity in an area reduced-pressure. Partial vaporization of the gasoline may occur under certain conditions, depending on the vapor pressure 10 of the liquid, its temperature and pressure; and \the liquid delivered, as shown in the sight glass indicator 3|, would have a foamy or milky appearance which is decidedly objectionable in the trade. The customer, seeing bubbles in the 7 liquid, assumes them to be air bubbles and not,

as is the fact, air-free gasoline made foamy in appearance because of bubbles of partially-vaporized gasoline. The diffuser which may be of the form shown in Fig. 4 or the vane type shown in Figs. 13 and 14, prevents the dissipation in eddies of the kinetic energy imparted to the gasoline by the impeller, and prevents cavitation. By the use of the difi'user, the velocity of the liquid discharged by the impeller is reduced gradually and without shock to the velocity of the liquid in the discharge pipe. The necessary conversion of kinetic energy into pressure energy is effected smoothly and efficiently, without the formation of eddies-resulting in a high pumping efilciency. The pressure is maintained more nearly uniform, irrespective of rate of delivery, over a considerable range. While it is important and desirable to secure the efilciency of pumping, the really necessary and critical thing is to so discharge the liquid that it will not have the objectionable milky or foamy appearance and this is secured by the use of a diffuser.

It is to be noted that the action of the centrifugal pump in whirling the liquid, removes any particles of foreign matter which may be carried in suspension in the liquid, out'of the inlet path to the displacement pump. The latter is thus protected against the entry of foreign matter which might, because of the closely fitting parts, interfere with its operation or cause undue wear of the parts. The displacement pump is only required to pump clean liquid and air or gases. The allusion to foreign matter has reference to the very fine particles that are almost always present and are carried in suspension in the liquid and are so fine that they are not removed by the screens or filters usually connected somewhere in the suction line to the pumping unit. There are no substantial quantities of solids entering this unit and the foreign matter, referred to, passes throughthe centrifugal pump and out :he discharge line as in other dispensing sysems.

The motor-driven pumping unit is designed to enable substantial savings to be effected in cost of manufacture over the apparatus heretofore used to do the equivalent work. The two pumps are directly connected to the shaft of the driving motor and are housed in a casing which includes as one element a special end plate for the motor,thus affording a very compact arrangement. Separate mountings for the pumps and driving connections between each pump and the motor are dispensed with and the air separator accessory is no longer necessary since its work is accomplished in the pumping unit. Additional savings in cost can be effected by the use of the die-cast linings for the centrifugal pump shown in Figs. 13 and 14. v

The construction is also such that there are few moving parts and few parts to wear andrequire servicing in the field. However, such servicing is readily accomplished when required. One simply removes the bolts II, after the electrical connections to motor 2| have been broken, after which the motor, displacement pump and the moving part of the centrifugal pump can be removed as one unit. No breaking of pipe connections is required and the work can be performed with only a very short interruption in the use of the apparatus, especially if. as is often the case, a new unit is substituted for the old one and the latter sent to the factory for reconditioning. 'Ihe displacement pump, however, is made as a separate unit and can be readily removed (by simply removing the impeller 81 and cap screws 91) and a new unit substituted. In

case the die-cast construction of Figs. 13 and 14 is used, it will also be necessary to remove screws I26 and plate I24. The centrifugal pump involving only the one moving part which is not subject to wear, should require no servicing. It will be seen that the design is such as to reduce to extreme simplicity the operation of servicing and inspection.

The invention thus affords by the use of the composite pumping unit described, substantial savings in manufacturing cost and in the cost of servicing the'apparatus in the field. It also results in much smoother and quiet operation. Its use in a meter type gasoline dispensing apparatus enables air, and gases to be separated from the liquid under all conditions regardless of the amount of air and the viscosity of the liquid, without the use of any additional apparatus for the purpose, and insures that air-free liquid only will be delivered to and measured by the meter and that the air-free liquid discharged will have a clear appearance and be free from foam.

What I claim is:

1. In apparatus ofnthe class described, an electric motor including its shaft and the end plates in which said shaft is rotatably mounted, a casing secured to one said end plate, such plate and casing forming between them a centrifugal pump chamber, said last named end plate having a recess therein adjacent said chamber, a displacement pump mounted in said recess and having a rotatable member fixed to said shaft, and a centrifugal pump impeller located in said chamher and fixed to said shaft, said casing having therein an inlet for the centrifugal pump and outlets one for each pump, the displacement pump having its inlet in direct communication with said chamber.

2. In apparatus of the class described, an electric motor including its shaft and the end plates in which said shaft is rotatably mounted, a casing secured to 'one said end plate, such plate and casing forming between them a centrifugal pump chamber, said last named end plate having a recess therein adjacent said chamber, a displacement pump mounted in said recess for removal and replacement as one unit and having a rotatable member fixed to said shaft, and a centrifugal pump impeller located in said chamber and fixed to said shaft, said casing having therein an inlet for the centrifugal pump and outlets one for each pump, the displacement pump having its inlet in direct communication with said chain-'- her.

3. In'apparatus of the class described, an electric motor including its shaft and its end plates in which said shaft is mounted, one said end plate having a central recess in its outer face encompassing said shaft, a displacement pump mounted in said, recess and having a rotatable member fixed to said shaft, a casing secured to the last-named end plate and cooperating with it to form a centrifugal .pump chamber, a cenpassage extending to said casing, said casing having a passage forming a continuation of said outlet passage and terminating with a port for connection to an outlet pipe, all constructed and arranged so that the motor with the displacement pump and said impeller may be removed as one unit leaving said casing connected to said several pipes.

4. In apparatus of the class described, an electric motor including its shaft and upper and lower end plates in which said shaft is mounted with its axis vertically disposed, the lower end plate having a centralrecess in its lower face encompassing said shaft, a displacement pump mounted in said recess for removal and replacement as one unit and having a rotatable member fixed to said shaft, a casing secured to the lower end plate and cooperating with it to form a centrifugal pump chamber, a centrifugal pump impeller located insaid chamber and fixed to said shaft, said casing having an inlet passage adapted for connection to an inlet pipe and extending axially to said chamber and a peripheral outlet passage leading from the chamber and adapted for connection to an outlet pipe, the inlet port of the displacement pump overlying and communicating with said chamber, said lower end plate having an outlet passage extending to said casing, said casing having a passage forming a continuation of said outlet passage and terminating with a port for connection to an outlet pipe, and a fixed support for said casing, all constructed and arranged so that the motor with the displacement pump and said impeller may be removed as one unit leaving said casing on its fixed support and connected to said several pipes.

5. In apparatus of the class described, an electric motor including its shaft and the end plates in which said shaft is rotatably mounted, a casing secured to one said end plate, such plate and easing forming between them a centrifugal pump chamber, said last-named end plate having arecess therein adjacent said chamber, a displacement pump mounted in said recess and having a rotatable member fixed to said shaft, 2, centrifugal pump impeller located in said chamber and fixed to said shaft, said last-named end plate having a bearing for said shaft axially spaced from the displacement pump and located on the opposite side thereof from said impeller, said last-named end plate having a chamber between the displacement pump and one side of said bearing, a seal ring mounted on said shaft in said lastnamed chamber and engaging the adjacent face of the displacement pump, said last-named end plate having a vent passage leading from said last-named chamber to the atmosphere for the escape of any inflammable vapors which may pass said seal ring and having also on the opposite side of said bearing a flame arrester encompassing said shaft and preventing the transmission of flame from within the motor along said shaft and through said bearing into said last-named chamber.

6. Pumping apparatus, comprising, a centrifugal pump impeller having a member carrying on one face thereof a plurality of vanes and on the opposite face an axially directed annular collar, first and second casing sections one on each side of the impeller and secured together and forming between them a chamber to enclose the impeller, a drive shaft mounted in the first section and extending through said collar in spaced concentrical relation and being secured to said impeller, said first section having in its inner face a recess opening into said chamber, a displacement pump mounted in said recess and driven from said shalt, a die-cast plate inset into and covering the inner face oi the first section and closing said recess except for a central opening through which said collar extends, said member having air passages through it .close to the axis and inside said collar, the second section having inlet and outlet passages for said pump chamber and cooperating with said die-cast plate to form the pump chamber and a difi'user connecting the pump chamber to the outlet passage.

'7. Pumping apparatus, comprising, a centrifugal pump impeller having a member carrying on one lace thereof a plurality of vanes and on the opposite lace an axially directed annular collar, first and second casing sections one on each. side of the impeller and secured together and forming between them a chamber to enclose the impeller, a. drive shaft mounted in the first 'pum'p chamber and cooperating with said die-cast plate to form the pump chamber'and a diiluser' passage connecting the pump chamber to the outlet passage, said plate having difiuser vanes extending in the difiuser passage and abutting the second named member.

WARREN H. DI LANCIY.