US2297185A - Pumping apparatus - Google Patents

Description

. Se t. 29, 1942. AIHOLLANDER ETAL I 2,297,185

PUMPING APPARATUS Filed June 11, 1940 4 Sheets-Sheet 1 INVENTORS BY OM50 ATTORNEYS Sept. 29, 1942. A. HOLLANDER ET AL 2,297,135

PUMPING APPARATUS.

Filed June 11, 1940 4 Sheets-Sheet 3 6 I 11 i z I H; I f 95 I 15 I 14 92 r W I +1! j I. 9/ I 10 444049 #01 LAND/5A ATTORNEYS Sept. 29, 194-2. A HQLLANDER AL 2,297,185

PUMPING APPARATUS Filed June 11, 1940 4 Sheets-Sheet 4 #44042 4041/74 05? Vxmvo 4. Hoary? INVENTORS a fl ATTORNEYS Patented Sept. 29, 1942 UNITED sTATEs PATENT OFFICE rummo APPARATUS Aladar Hollander and Value assignors to geles, CaliL,

A. Hoover, Los An- Byron Jackson 00.,

Huntington Park, Calii'., a corporation of Delaware - Application June 11, 1940, Serial No. 339,896 1 z Claims. (01.103-113) This invention relates generally to pumping apparatus, and particularly to pumping apparatus adapted to handle highly volatile liquids such as butane, propane, and other liquefied petroleum gases.

In ,our ,copendingapplication Serial Number 331,344, filed April 24, 1940, for Pumping apparatus, 'we have disclosed a pumping system for transferring liquids of the aforementioned type from an underground storage tank to a delivery point such as the fuel tank of a motor vehicle or a loading rack for filling bottles or other containers. In accordance with prescribed safety regulations, the tank and the receiver of the pump unit are connected by piping extending through the upper portions of the tank and re ceiver and hence disposed at'a higher elevation than the tank and the major portion of the receiver. If the tank and receiver are in open communication with each other, the pressures in the respective vessels will equalize when the pumping unit is idle, but during operation of the pump the pressure within the receiver will be lower than that within the tank by an amount equal to the loss of head due to friction in the connecting piping. The pressure at the highest point in theconnecting piping will be lower than that in the tank by an amount'equal to the friction los's,up to that point, plus the static head due to superelevation of that point above the level of liquid in the tank.

The pressure normally storage tank containing butane, propane, or other liquid having a vapor pressure greater than atmospheric pressure, is the vapor pressure of the liquid. As liquid is withdrawn from the tank, vaporization occurs within the tank.

to maintain the pressure at the vapor pressure of the liquid. It will be apparent, therefore,

that when the pump in the receiver is operating,

the drop in pressure in the receiver due to triction loss in the connecting piping will cause vaporization of pump liquid unless, means are provided .to offset the pressure drop and main-.

tain the pressure in the receiver at least equal to the vapor pressure of the liquid.

drop in the connecting line and thus avoid vaporization in the receiver.

' ratus at a lower tainer, and connecting inlet is preferably of v the pressure prevailing in a closed a In the above-mentioned copending application this pressure drop is offset by the provision .oi

an ejector in the storage tank. The ejector is pumping apparatus in the receiver, and is ca-;. pable of increasing .the pressure of the liquid preferably return it to the storage tank.

actuated by pump liquidby-passed from the 9 enlarged scale, taken on A principal objectof this invention to m. vide pumping apparatus particularly adapted to handling highly volatile liquidsand embodying more. eflicient and less costly means for ,transierring pump liquid from a storage container to the pumping apparatus. In a preferred embodiment of the invention, this object is attained by disposing the receiver of the pumping'appaelevation than the storage conthe container and receiver by piping forming a siphon tube. The static-head oithe pump liquid in the storage container-due to its elevation above the pump sufllcient magnitude to offset the friction loss in the siphon tube, thereby maintaining a pressure at the pump inlet at least equal to the vapor pressure of the liquid, and preventing evaporation of the liquid at that point. In the upper portion of the siphon tube prevailing in the storage tank, and, if the pressure inthe storage tank is the vapor pressure of the liquid at the prevailing temperature 'in the tank, some evaporation will take placein the upper portion of the siphon tube. In order to prevent accumulation of vapor, we propose to evacuate the vapor from the siphon tube and In the-preferred embodiment of the invention the evacuation of thevapor is effected by an ejector actuated by pump liquid. The energy required to condense the vapor formed in the siphon tube, and to return it to the storage tank at a slightly increased pressure, is. materially less than that required toactuate a liquid ejector mounted in the storage tank, as described in the aforementioned copending application.

Other objects and one embodiment and a modification thereof, reference being had to the accompanying drawings wherein:

ing our novel pumping apparatus; I v I Figs. 2 and 29 are longitudinal'sectional views of the lower and upper portions, respectively,

of the pump unit shown in Fig.1; V Fig. 3 is atop plan view of thepump unit;

Fig. 4 is-a transverse sectional view takenon line 4-4 of Fig, 29;

Fig. 5 is a longitudinal sectional view, on an line 5-5 of'Fig; 4;;

will be slightly lower than that advantages will be appa- I rent from the ,foregoing' detailed'description of y Fig. 6 is a transverse sectional view taken on line 6-6 of Fig. 2;

Fig. 7 is a longitudinal sectional view of a modification of the pump unit; and

Fig. 8 is a top plan view of the pump unit of Fig. 7.

Referring to Fig. 1 of the drawings, the loading and transfer station depicted therein is of the underground type in which a large capacity storage tank A is buried beneath a pit B, and a pump unit C is disposed in a well D sunk below a pit E. The pits B and E are preferably lined with concrete and are covered by usual steel grating, and house the piping connections between the tank and pump as well as various auxiliary pipes and valves, the latter being accessible through hand holes in the grating. Thus the only equipment projecting above the ground or floor level are the starting and stopping controls and the inlet and outlet pipes.

The pump unit C is of the type described in detail in our aforementioned copending application, and comprises generally an outer barrel or receiver ||l having a permanently closed lower 1 end and a removable cover plate II at its upper end, and a motor-pump unit comprising a multistage pump 2 and a submersible electric motor |3 suspended within the barrel' from the under side of the cover plate by means of a'discharge column I4. An inlet nozzle |5.is formed in the barrel adjacent its upper end, and a discharge nozzle I6 is secured to the cover plate II in alignment with the discharge column l4. An electric cable l8 extends from an external source of current through .suitable control switches and relays (not shown) to a pothead l9 secured to the outer side of the cover plate, and is connected, through a second pothead 20 on the inner side'of the cover plate, with an inner cable section 2| extending to the motor l3. The potheads l9 and 20 may be of the construction illustrated and described in detail in our aforementioned application, and hence a detailed description thereof is deem unnecessary.

unit C are connected by a conduit 25 extending from a pair of risers 26, 21 in the tank to the inlet nozzle |5-'of'.the receiver. In this connection it will be observed that the conduit 25 is located above the tank, in accordance with prescribed safety regulations. If it were permissible, it would be preferable from an operating standpoint to connect the tank and pump by a pipe extending from the lower portion of the tank. This is not permissible, however, because of the danger of underground leakage from connections which are inaccessible for inspection and repair. While we have shown two riser pipes 26 and 21 in the tank, it will beunderstood'that a single pipe may be used if desired. By the use of a plurality of pipes, however, a plurality of relatively small and light weight check valves 28 and 29 may be used at the lower ends of the pipes, thus reducing the pressure drop across the valves.

A discharge line 32 extends from the outlet nozzle l6 to a manually operated shut-oi! valve 33 in the pit B, and thence to a solenoid-operated valve 34,. the purpose of which will be described hereinafter. From the valve 34 the discharge line extends to a liquid meter 35 and thence to a flexible dispensing hose 36 equipped with a manually-operated valve 31 at: itsiouter end. For purpose of illustration, the hose 36 is shown attached to the fuel tank of a motor vehicle indicated at 38. A by-pass line 46 extends provided in .from the discharge line 32 to the tank A, and is hose 46 is connected to the pipe 25 beyond the valve 45, and is adapted to be connected to the outlet of a tank truck, indicated at 41, or to any other source of liquid supply. A pressure equalizing line 48 is connected at one end to the tank A and is adaptedto be connected to a suitable fitting on the tank truck 41, and is provided with a shut-off valve 49. Valves 50 and 5| are also the riser pipes 26 and 21, respectively.

Mounted on the panel 55 adjacent the solenoid valve 34 are a pair of push-button switches 56 and 51. The switch 51 controls the circuit of the submersible motor l3, and the switch 56 controls the solenoid valve 34.

In order to operate the pump unit to dispense liquid from the tank A to a container such as the fuel tank of the vehicle 38, the valves 33, 50 and trifugal pump having a shut-ofi head well below the safe pressure capacity of the system, the

solenoid valve 34 may be closed when the meter 35 registers the desired quantity, and the motor may thereafter be de-energized. It i considered preferable, although not necessary, that the solenoid switch 56 be of the type which must be held closed by the operator in order to maintain the valve 34 open, and which opens automatically and closes the valve when the operator releases the switch.

It is possible to dispense liquid into several containers in succession without de-energizing the motor and without. causing the pump to operate against the full shut-oil head while changing the connections at the dispensing hose 36. This is accomplished by opening the valve 4| and allowing the pump to discharge back into the tank A through the by-pass line 46 while changing the hose connection.

The tank A may be filled from the tank truck or other source by pumping from the tank truck to the tank A with the pump unit C. In this case the valves 50 and 5| are'closed and the valve 45 is opened to establish a connection from the tank truck to the receiver ID of the pump unit, the valve 43 is opened tolequalize the pressures in the tank truck and the tank A, and the valve 33 is closed and valve 4| opened to connect the tank A'with the discharge side of the pump. Upon closing the switch 51, the pump forces liquid from the receiver l6 into the tank A, the receiver being maintained full by gravity flow from the tank truck through the lines 44 and 25.

the' pump isopen to the receiver in through a a strainer 63,- to the lower end of which is secured an adapter 64 and the housing 65 of the motor The motor I3 is preferably of the type described and claimed in our Patent No. 2,171,749, dated Sept. 5, 1939, for Submersible motor assembly, and the auxiliary devices for maintaining a pressure balance between the pump liquid in the receiver and the dielectric liquid in the motor housing while isolating-these two liquids from each other by an intermediate liquid, and for cooling the motor, maintaining the proper level of the intermediate liquid, and for venting the receiver, are preferably in all essential respects similar to the means provided for these purposes in our aforementioned co-pending application Serial No. 331,344, filed April 24, 1940. Therefore a brief description of these devices will suflice, reference being had to the above-mentioned application for a detailed description.

An inverted U-tube composed of pipes 10 and TI is connected at one end to the lower portion of the motor, housing, and is in open communication at its opposite end with the lower portion of a body of intermediate liquid filling the lower portion of the receiver 10, as indicated at I2.

This liquid may be any liquid which has a greater specific gravity than both the pump liquid and the dielectric liquid in the motor housing, and which is immiscible with both of these liquids. The intermediate liquid extends upwardly around the motor housing to a level indicated at '53, which is a sufficient distance below the strainer 63 to provide a stagnant body of pump liquid above the intermediate liquid, and thus avoid any intermixing at the surface of contact of the two liquids. A line I3 extends from the upper end of the U-tube Ill, II to the cover plate II. A second U-tube 14 has one end in open communication with the pump liquid and the opposite end connected to the adapter housing, to provide a conduit ofiering the same frictional resistance, and hence the samepressure drop, between the pump liquid and the outer side of the mercury seal in the motor, as is offered by the U-tube 10, ll between the intermediate liquid and the inner side of the mercury seal. By this arrangement, sudden changes in pressure will not unbalance the mercury seal.

A cooling jacket 15 surrounds the motor housing and extends downwardly into the intermediate liquid, the lower end of the jacket being closed to exclude intermediate liquid therefrom and the upper endthereof being opento admit pump liquid. Perforated. cooling pipes 18 extend from an intermediate stage of the pump l2 down-v the receiver without causing evaporation within the receiver of any substantial amount of the pump liquid.

Referring now to our novel means for trans- I ferring pump liquid from the tank A to the receiver I, it will be observed from Fig. 1 that the strainer 63, forming the inlet from the receiver to the pump, is located a. very substantial distance below the bottom of the tank A, whereby the riser pipes 26 and 21, the connecting pipe 25, and the receiver constitute in effect a siphon in which .the effective head is that'produced by the column of liquid between the strainer 63 and the level of the liquid in the tank. So long as this head is equal to or greater than the loss of head due to friction in'the riser pipes 26 and '21 and thetransfer pipe 25, the pressure of the liquid at the strainer will be at least as great as that in the tank. The liquid in the tank is always under a pressure at least equal to the vapor pressure of the liquid, and hence vaporization at the pump inlet and consequent loss of suction by the pump cannot occur.

In-the upper portion of the siphon, above the level of the liquid in the tank, there will occur a slight pressure drop due to the loss of head resulting from the higher elevation, and evaporation of some of the pump liquid will take place. The amount of vapor formed depends upon the pressure drop and the'amount' of vaporization required to lower the temperature of the liquid 7 to that at which the liquidhas a vapor pressure equal to the-lower pressure at that point. It will be understood that vaporization begins in 'the riser pipes just above the liquid level in the tank.

Another factor is thus introduced, which afiectsthe conditionjof dynamic equilibrium which is eventually established. This factor is the lifting effect of the expanding gas in'the riser pipes, resulting in reducing the pressure drop due to the elevation of the liquid above the liquid level in the tank.

Once the flow of liquid from the tank into the receiver is started, the velocity of the stream will carry a substantial proportion of the vapor into the lower portion of the receiver, where it is recondensed because of the higher pressure pre-' vailing there. For this reason it is very desirable, if not essential, that the pump'inlet at the strainer 63 be located a substantial distance below the level of the liquid in the tank, in order to provide a reservoir of suflicient capacity to supply-the pump while the flow through the wardly alongside'the motor housing, for clrculating a small amount of pump liquid in heat exchange relationship to the motor to dissipate the heat generated by the motor windings. Abafile plate 11 extends outwardly from the upper extremity of the jacket. 15 to protect the liquid contact surface I3 from-currents within the pump liquid.

A liquid levelcontrol line extends from the cover plate H to a point slightly below the level transfer'pipe is being established.

In order to prevent accumulation of vapor in the ripper portion of the siphon, and to maintain the system filled with liquid both during operation and while idle, we prefer to evacuate any vapor formed in the upper portion of the receiver. In the preferred form of the invention "the evacuation of the vapor is eifected by a va- 13 of the intermediate liquid, .and may be vented if it is desired to ascertain whether a change in the level 13 has occurred. An oil filler line 8| extends from the cover plate to the upper end of the motor housing to enable the dielectric liquid to be replenished if this should become necessary. A blow-off line 82 extends from the cover plate to a point close to the lower end of the cooling chamber within the jacket 15, to en-' able the volatile pump liquid to be blown from por ejector 90 actuated by pump liquid at discharge pressure. As most clearly shown in Fig. 5, the ejector is of a conventional type and comprises a body 9| having a diverging discharge nozzle 92, a converging jet nozzle 93 connected to the pump discharge pipe l4, and a vapor inlet pipe 94 communicating with the interior of the receiver III. A vapor discharge pipe extends from the nozzle 92 through the cover plate and, as shown in Fig. 1, is connected to a vapor return line 96 leading back to-the tank A.

In this manner a small amount of pump liquid is by-passed from the discharge pipe I! back to the tank to re-compress and condense any vapor which accumulatesin the upper portion of the receiver. The amount of by-pas sed liquid is very small, however, since the energy required to raise the pressure of the vapor in the receiver to the pressure in the tank is very slight, and hence the decrease in the discharge from the pump unit is negligible.

As shown in'Fig. 1, a vent line 91 extends upwardly from the vapor return line 96 and is open to the atmosphere at an elevated point. Suitable shut- oif valves 98 and 99 are provided in the vent line 91 and the vapor return line 95, respectively, whereby the upper portion of the receiver may be selectively vented to the atmosphere (to vent air therefrom when filling the system initially) or connected to the tank A to return vapor thereto.

In Figs. 7 and 8 we have shown a slightly modified construction of the pumping unit C of Fig. 1. In this form of the invention a different type of pump is employed, and the receiver Iii is subjected to the discharge pressure instead of to suction pressure as in the previously described form. The two pumping units are in all other essential respects substantially identical.

The pump I 2 of Fig. 7 is preferably the inner unit of a double-case multistage centrifugal pump such as that disclosed in U. S. Letters Patout No. 1,997,824 to Aladar Hollander, dated April 16, 1935. The inner impeller casing of such a unit is of the axially split type and is adapted to be subjected externally to the final discharge pressure of the pump. The suction inlet of the pump is connected to a relatively long, large diameter suction pipe suspended from the cover plate II of the receiver and connected to an inlet nozzle l, which is adapted to be connected to the transfer pipe 25 of Fig. 1. pump discharges through an outlet l1 directly into the receiver l0, and a discharge nozzle I 6 extends through the cover plate and is adapted to be connected to the discharge line 32 of Fig. 1.

The motor I! and its auxiliary equipment are shown as substantially identical with that -of Fig. 3, and hence a description thereof is deemed unnecessary.

In this form of the invention, the suction pipe I 4 forms the discharge leg of the siphon between the tank A and the pumping unit, the

other leg being formed by the riser pipes 26 and 21 in the tank. The pipe I4 is of unusually large diameter in order to provide a suction reservoir for the pump, of sumcient capacity to supply the pump while the flow is being established through the transfer pipe 25. The pipe I! is also preferably of suflicient length ,to dispose th inlet of the pump a substantial distance below the bottom of the tank, as in the form previously described, in order to insure that vaporization does not occur at the pump inlet.

In this form of the invention, any vaporization of pump liquid resulting from a pressure difference between the tank A and the suction pipe ll will occur in the suction nozzle l5", which in this case is the highest point in the siphon tube. The vapor ejector 80, therefore, is arranged to evacuate the vapor from the nozzle i5 through a vapor inlet pipe 94 connected to the ejector and extending upwardly to adjacent the upper end of the inlet nozzle. Pump liquid at pump discharge pressure is admitted to the jet nozzle from the interior of the receiver through an inlet 93' at the lower extremity of the ejector body,

The-

tainer to a. receiver for a pump in such a way as to maintain the inlet of the pump submerged at all times. The inlet conduit to the pump is "maintained filled with pump liquid in the liquid phase, both during operation of the pump and while the latter is idle, and the system is operable to automatically establish and maintain a predetermined pressure difference between the container and the receiver during operation of the pump, and thus induce flow to the pump inlet at the required rate. The loss of overall efiiciency, resulting from the by-passing of pump liquid back to the tank, is reduced to a minimum and discharges along with the re-condensed vapor through the vapor return line 96' corresponding because of the negligible amount of energyrequired to recondense any vapor formed in the receiver. It will be appreciated that many factors are involved in the establishment of a condition of dynamic equilibrium during the pumping operation, several of which factors have been mentioned previously, such as the cooling effect of evaporation and the consequent reduction in the vapor pressure of the liquid, and the gas-lift effect of the expanding vapor in the rising column of liquid. These and other less apparent factors contribute to the ultimate result, namely-the continuous vaporization of a small percentage of the pump liquid at a pressure slightly below that of the storage tank, and requiring the absorption of only a negligible portion of the energy output of the pump in order to recompress and condense the vapor.

Although we have illustrated and described in detail a-preferred embodiment of the invention and a modification thereof, it is to be understood that the invention is not limited to the precise details shown and described herein, but is of the full scope of the appended claims.

We claim:

1. Pumping apparatus for volatile liquids comprising in combination: a closed storage container; a discharge line; a'pump for delivering liquid from said container to said discharge line; said pump having an outlet connected to said discharge line and having an inlet positioned below the level of liquid in said container; conduit means connecting said container with said pump inlet, a portion of said conduit means being disposed at a higher level than the liquid level in said container; and auxiliary pumping means connected between said conduit means and said container for transferring vaporized pump liquid fromsaid conduit means back to-said storage container.

2. Apparatus as described in claim 1, in which said auxiliary pump means comprises ejector means having an eduction inlet communicating with said conduit means, having a discharge outlet communicating with said container, and having an actuating-liquid inlet connected to said pump outlet, whereby said ejector is operable during operation of said pump to transfer vaporized pump liquid from said conduit means back to said storage container.

3. Pumping apparatus for volatile liquids comprising in combination: a closed storage container; a closed receiver; a pump mounted in the prising,

receiver and having an inlet and an outlet, the "1 inlet being disposed a substantial distance below the liquid level in said container; transfer conduit means connecting said. container with said pumpinlet, a portion of said transfer conduit means being disposed at a higher elevation than the liquid level in said container; a liquid-actuated ejector having an actuating-liquid inlet and. pump-discharge conduit .means connecting it with said pump outlet whereby the ejector is adapted to receive pump liquid from said pump,

having an eduction inlet communicating with said transfer conduit means, and having a discharge outlet communicating with said container, said ejector being operable during operation of said pump to transfer vaporized pump liquid from said transfer conduit means back to said ceiver inlet passage and a discharge outlet in open communication with the interior of said receiver; driving means for said pump; a transfer conduit extending from said storage container to said receiver inlet passage and having at least a portion thereof disposed at a higher-elevation than the level of. the liquidin said container; and

means for withdrawing vapor formed in the elevated portion of said conduit and returning it to said container, said means comprising a liquidactuated ejector having an actuating-liquid inlet adapted and arranged to admit pump'liquid disstorage container; and a discharge line in open communication with said pump-discharge conduit means; said receiver constituting a portion of one of said conduit means.

4. Pumping apparatus for volatile liquids comprising in combination: a closed storage container; a closed receiver; a discharge line; a pump mounted in the receiver and having an inlet and an outlet, the inlet'being disposed a substantial distance below the liquid level in said container, and the outlet being connected to said discharge line; transfer conduit means connecting said container with said pump inlet, a ,por-

tion of said transfer conduit means being disposed at a higher elevation than the liquid level in said container; a liquid-actuated ejector having an actuating-liquid inlet and conduit means connecting it with said pump outlet, having an eduction inlet communicating with said transfer conduit means, and having a discharge outlet communicating with said container, whereby said ejector is operable during operation of said pump to transfer vaporized pump liquid from said transfer conduit means back to said storage con- .charged by said pump,

an eductioninlet adapted and arranged to admit vapor formed in said conduit, and a discharge outlet communicating with said storage container.

7. Pumping apparatus as set forth in claim 4, in which said ejector is. mounted within said receiver, and in which said eduction inlet is in open communication with the interior of said receiver adjacent its upper end.

8. Pumping apparatus as set forth in claim 6, in which said ejector is mounted within said receiver, and in which said actuating-liquid inlet is in open communication with the interior of said receiver.

9. Pumping apparatus as set forth in claim 6, in which said ejector is-mounted within said receiver, and in which said actuating-liquid inlet is in-open communication with the interior of said receiver, and said eduction inlet is in comtainer; and the interior of said receiver being in direct communication with said pump inlet and constituting a portion of said transfer conduit means.

5. Pumping apparatus for volatile liquids comprising in combination: a closedstorage container; a closed receiver; .a discharge line connected to said receiver; a pump mounted in the receiver and having an inlet and an outlet, the inlet being disposed a substantial distance below the liquid level in said container; transfer conduit means connecting said container with said pump inlet, a portion of said conduit means being disposed ata higher elevation than the liquid level in said container; a liquid-actuated ejector having an actuating liquid inlet and pump-dis: charge conduit means connecting it with said pump outlet, having an eduction inlet communicating withsaid transfer conduit means, and having a discharge outlet communicating with said container, whereby said ejector is operable during operation'of said pump to transfer vaporized pump liquid from said transfer conduit means back to said storagecontainer; the interior of said receiver being in direct communication with said pump outlet and said discharge line, and constituting a portion of the said conduit means that connects the actuating-liquid inlet of said ejector with said pump outlet.

6. Pumping apparatus for volatile liquids comin combination: a closed storage container; a closed receiver having fluid inlet and outlet passages; a

and having a suction inlet connected to said remunication with the elevated portion of said transfer conduit.

10. Pumping apparatus for volatile liquids comprising, in'combination: a close'dstorage container; a closed receiver having a portion thereof extending a substantial distance below the I level of the liquid in said container and having fluid inlet and outlet passages through the wall thereof, the interior of said receiver being sealed off from mounted in said receiver and comprising a pump casing having inlet and outlet openings, one of which is in communication with one of said fluid passages and the other of which is in open communication with the interior of said receiver, said inlet opening being disposed a substantial distance below the liquid level in said container; transfer conduit means forming a siphon connection between said storage container. and said. pump inlet, the upper portion of said siphon connection being disposed at a higher elevation than the liquid level in said storage container,

and the discharge leg of said siphon connection being of relatively large capacity and forming a storage chamber of sufilcient'capacity to maintain said pump inlet submerged in pump liquid while-siphonic flow is being established during initial operation of said pump.

11. Pumping apparatus for volatile liquids comprising, in combination: a closed storage con- -tainer; a closed receiver having fluid inlet and outlet passages extending through the wall there- 7 of and having the interior thereofsealed off from i passage,

pump mounted in said receiver pump; a transfer conduitgnnecting the conthe surrounding medium, said receiver having a portion thereof extending a substantial distance below the level of theliquid in said container; a

pump mounted in said receiver and having a suctioninlet in open communication with the interior of said receiver and having a discharge outlet communicating with the receiver outlet said suction inlet being disposed a substantial distance below the level of the liquid in said storage containers driving means for said the surrounding medium; a pump tainer and the receiver inlet passage .and fo ing with the receiver a siphon connection between the container and the pump inlet; the portion 'of said receiver'above the pump inlet forming a pump priming chamber of suflicient ca-' pacity to maintain said pump inlet submerged in pump liquid while siphonic flow is being estabwith the interior of said receiver; driving means for said pump; a transfer conduit extending from said storage container through the wall of said receiver and into direct communication with said lished through said transfer conduit during initial operation of said pump.

12 Pumping apparatus comprising, in combination: a storage container; a closed receiver having a fluid outlet passage extending through the wall thereof, said receiver having a portion thereof extending a substantial distance below the level of the liquid in said container; a pumpmounted in said receiver and having a suction inlet disposed a substantial distance below the level of the liquid in said storage container and having a discharge outlet in open communication ALADAR HOLLANDER. VAINO A. HOOVER.

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