US2280087A

US2280087A - Pumping apparatus

Info

Publication number: US2280087A
Application number: US331344A
Authority: US
Inventors: Hollander Aladar; Vaino A Hoover
Original assignee: Byron Jackson Co
Current assignee: Byron Jackson Co
Priority date: 1940-04-24
Filing date: 1940-04-24
Publication date: 1942-04-21
Anticipated expiration: 1959-04-21

Description

April 21, 1942. A. HOLLANDER ET'AL PUMPING APPARATUS Filed April 24, 1940 4 Sheets-Sheet 1 INVENTORS BY a M ATTORNEYS April 21, 1942.

A. HOLLANDER ET AL PUMPING APPARATUS Filed April 24, 1940 4 Sheets-Sheet 2 44404,? A ozm/mm kw/vo A. 001 5? INVENTORS ATTORNEYS BY o-u/ April 21, 1942.

A. HOLLANDER ET AL 0,087

PUMPING APPARATUS Filed April 24, 1940 4 Sheets-Sheet 3 4.4404? A ozm/vam fi m 0 4. #001457? INVENTOR BY 5M5 ATTORNEYS April 21, 1942.

A. HOLLANDER ET AL 2,280,087

PUMPING APPARATUS Filed April 24, 1940 4 Sheets-Sheet 4 ATTORNEYS Patented Apr. 21, 1942 PUMPING APPARATUS Aladar Hollander and Vaino -A. Hoover, Los Angeles, Calif., assignors to Byron Jackson 00., Huntington Park, Calif., a corporation of Delaware Application April 24, 1940, Serial No. 331,344

11 Claims.

This invention relates generally to pumping apparatus, and particularly to apparatus for pumping liquids which must be handled without leakage because of their volatile,.poisonous, corrosive, obnoxious, or other characteristic which renders it imperative that leakage of the liquid from the pumping apparatus be reduced to a minimum, and preferably that it, be eliminated entirely. I

High pressure pumps for handling ordinary, harmless liquids customarily embody .a pump shaft projecting from the pump casing, preferably at'the suction end thereof, in order to subject the stuifingbox around the shaft to the lowest pressure and thereby minimize leakage of pump liquid from the casing. So far as we are aware, however, no stuflingbox has yet been developed which will maintain-an absolute seal during a sustained period of use, particularly against a pressure of substantial magnitude. Many instances may be cited in which the liquid to be pumped is of such a nature that even very slight leakage creates a hazardous condition, as a consequence of which the conventional-pump ing equipmentheretofore available is not suitable for handling such liquids. For example, liquefled petroleum gases such as butane and propane inevitable leakage of some of the volatile liquid through the stufllngbox. Even-slight leakage of such liquids is highly objectionable because their'volatile and explosive nature.

Another service which is incapable of-boing properly handled by a pump having a stuiilngbox about the pump shaft at the suction end or, the

p 40; of

as in that previously discussed with reference to propane and butane, the liquidenters the pump at relatively high suction pressure, and, so long as stuflingboxes are relied on to seal the shaft openings in the pump casing, some leakage will inevitably occur.

Many industrial, processes involve pumping liquids of a. corrosive, poisonous, or obnoxious nature. under conditions which are such that stufiingboxes cannot be relied on to prevent leakage, even though high pressures are not encountered. For example, many industrial solutions are what are known as fugitive liquids-i. e.,

they cannot be confined by stumngboxes even at low pressure because of their unusually low surface tension or other uncommon physical property.

Various prior attempts have been made to overcome the difflculties enumerated above. Stuflingboxes have been improved somewhat, but

only to the extent of reducing but not eliminat-,

motor in a single housing which is completely filled with pump liquid. Inasmuch as the motor must operate immersed in the pump liquid, successiul operation of such a unit is limited, -however, to those cases in which the liquid being pumped is not only a good lubricant but also has good dielectric properties and is otherwise harmless to the motor. The scope of application of such a unit is thus so limited as to render it of only negligible commercial value.

In a further. attempt to widen the scope of usefulness of a unit such as that discussed in the preceding paragraph, it has also been proposed to fill the motor housing of such a unit with an inert gas or, alternatively, with a dielectric liquid. Gasfllled motors,'however, present pump casing, is that of boosting thawedure of a harmful liquid froman initial high rasure to a still higher pressure.

boosterpumps for handling hydrocarbons acids, etc., in oil refineries, and by booster stations in long pipe lines for transporting crude oil from producing oil fields to refineries or for transporting gasolene or other refinery products from re-' flneries to distribution centers. In this case,

Two common,"

examples of this service are that rendered by additional problems of heat transfer and of bearing lubrication andconsequently are less desirable than oil-filled motors Prior] attempts to avoid the use are stufllngbox by enclosing an oil-filled motor and a pump in a single casing filled with pump/liquid, have beenlimited to those cases where the pumped liquid is not readily miscible with'ithe oil or other dielectric liquid contained in the motor housing. If the two liquids are miscible, a progressive molecular interchange inevitably occurs inthe zone of contact of the two liquids, resulting in contaminaliquid, a portion thereof is necessarily displaced box, the foregoing expedient falls far short of providing an adequate and universally applicable solution of the problem.

This invention has as its principal object the provision of a system and apparatus for pumping liquids, characterized by the elimination of all stuffing boxes and the consequent prevention of any leakage whatsoever of pump liquid from the apparatus.

A further object is to provide a pumping apparatus which is' capable of handling, without leakage, a wide variety of liquids which cannot be handled by conventional pumps equipped yvith stuffingboxes, and which is particularly adapted to handling highly volatile liquids such as gasoline, butane and propane.

- underground shaft or pit and having suction and The invention in its broader aspects contemplates the complete enclosure' of the pump and of an oil-filled, pressure-balanced, submersible electric motor within a fluid-tight casing which is adapted to be substantially filled with the liquid being pumped, either at suction or discharge pressure. The apparatus is rendered universally applicable to the pumping of a wide variety of liquids, irrespective of their miscibility with oil or other dielectric'liquids, by completely isolating 85',

the pumped liquid from the dielectric liquid contained in the motor housing.

A still further object of this invention is to provide pumping apparatus of the type wherein a pump and a direct-connected electric motor are dielectric liquid, the pump-liquid and the dielectric liquid being in turn isolated from each other by a liquid seal surrounding the motor shaft at its juncture with the motor housing.

A still further object of the invention is to provide pumping apparatus of the type set forth in the preceding paragraph, wherein the dielectric within, the motor housing is subjected to the pressure of the pump liquid within the outer vessel, thus eliminating the necessity of a stufling box about the juncture of the motor shaft and 6!? the motor casing.

Provision must also be made in oil-filled, pr essure-balanced submersible motors for enabling the motor to breathe-that is, to provide for the expansion of the dielectric liquid due to rise of temperature during the operation of the motor, and the corresponding contraction of the dielectric liquid as it cools down when the motor is stopped. During expansion of the dielectric from the motor housing, and is returned to the housing upon subsequent contraction. In order to maintain the aforementioned isolation of the pump liquid from the dielectric liquid while at the immiscible with both of the other liquids. In 76 this manner, while open communication is established between the interior of the motor housing and the interior of the outer vessel, the dielectric liquid and the pump liquid are prevented from directly contacting each other by the interposed third liquid.

A still further object of the invent is o p vide pumping apparatus of the type wherein a pump and a motor are encased in a fluid-tight pressure vessel through which the pump liquid flows, and the housing of the motor contains a dielectric liquid, and wherein the dielectric liquid within the motor housing is in pressure transfer relation to the pump liquid at each end of the motor housing but is isolated from the pump liquid by separate bodies of intermediate liquids, one of which surrounds the motor shaft at its juncture with. the motor housing and the other body of intermediate liquid being interposed between quiescent bodies of pump liquid and dielectric liquid.

In a preferred embodiment of the invention the outer vessel is an elongated cylinder adapted to be mounted in an upright position, with the major portion of the vessel disposed within an discharge nozzles for pump liquid adjacent its upper end. The pump and direct-connected motor are mounted within the outer vessel with the pump suspended from a removable cover plate enclosing the upper end ofthe vessel, and the motoris suspended beneath the pump. Under these circumstances the motor is not mounted directly in the path of flow of the pump liquid through the outer vessel, and hence is deprived of the cooling effect of the movingstream of pump liquid. A further object of the invention is to provide means for cooling the motor, preferably by by-passing a small proportion of the pump liquid in heat-exchange relationship .with

the motor housing.

A still further object of the invention is to provide a unit of the aforementioned type wherein the pump and motor and its accessories are as-' sembled'as a unit independently of the outer vessel. In a preferred embodiment, this object is attained by suspending the pump and its motor from the under side of the cover plate of the outer vessel, the power leads for the motor and the auxiliary piping being also attached to the cover plate. In this manner'the outer vessel performs the sole function of a liquid container, and all of the operative parts of the unit may be assembled prior toinsertion into the vessel, and may be removed as a unit for inspection and repair simply by detaching the'cover plate from the outer vessel.

As previously mentioned, one of the principal objects of this invention is the provision of apparatus particularly adapted for pumping butane and propane and other liquids having a vapor pressure greater than atmospheric pressure. For obvious /reasons, the handling of such liquids involves various problems not encountered when handling liquids which remain in the liquid phase at atmospheric pressure. For example, a vessel such as the outer vessel in the instant case, when filled with gaosline, may be vented to the atmosphere and will remain full, whereas if it were filled with butane or propane and vented to the atmosphere it would blow itself empty. If evaporation occurs within the vessel, the cooling effect would be such as to lower the temperature within the vessel to such a low degree as to have a detrimental effect on the'equipment within the container. If an intermediate liquid is employed as mentioned above, there is the possibility that the temperature may be lowered below the freezing point of the intermediate liquid. A still further object of this invention is to provide pumping apparatus of the type discussed above, which is especially adapted to handle liquids having super-atmospheric vapor pressure, and in which provision is made for venting the outer vessel without materially lowering the temperature therein. 7

A still further object is to provide pumping apparatus of the aforementioned type having a novel and improved means for electrically connecting the motor within the outer vessel to an external source of electrical energy. A more specific object aims to provide a construction whereby the electrical conductor cable is divided into two: sectionsan inner section within the pressure vessel and subjected to the pressure of the pump liquid. and an outer section under atmospheric pressure-the two sections being separable from each other while the vessel is maintained under pressure. Such an arrangement renders possible the disconnection and replacement of the outer section of conductor cable without venting the pressure vessel or otherwise isturbing the equipment within the vessel. A still further objectis to provide a connection between the above-mentioned cable sections and the removable cover plate of the outer vessel, which per-' ing and distributing stations for liquefied petroleum gases such as butane and propane are usually equipped with underground storage tanks.

This creates a problem oftransferring the butane or propane from the storage tank to the pumping apparatus while maintaining it under sufllcient pressure to prevent vaporization. Our novel pumping apparatus embodies simple and effective auxiliary pumping means which constitutes an improvement over prior devices for this purpose.

Other objects andadvantages will be apparent from the following detailed description of one embodiment-of the invention, reference being had to the accompanying drawings-wherein:

Fig. l is a vertical sectional view illustrating the application'of our novel pumping apparatus to a loading or distributing station;

Fig. 2 is a top plan view of the'installation il lustrated in Fig. 1;

Fig. 3 is an enlarged view, partly in elevation and partly in vertical section, of the lower portion of the pumping apparatus shown schematically in Fi 1;

Fig. 3" is a view similar to Fig. 3, showing the upper portion of the pumping apparatus;

Fig. 4 is an enlarged" top plan view of the pumping apparatus;

Fig. 5 is a vertical sectional view taken on line 5-5 of Fig. 4;

Referring to Figs. 1 and 2, we have shown our novel pumping apparatus, generally designated A, as installed in a loading or distributing station particularly adapted for handling butane and propane. It will be understood, of course, that this is solely for illustrative purposes and that the pumping apparatus is -adaptable to a wide field of uses. In the. illustrative embodiment, the pumping apparatus is connected by suitable piping to an underground storage tank B, and is adapted to dispense liquid from the tank to containers such as the fuel tanks of motor vehicles, drums or other containers for liquefied petroleum gas for domestic use, etc.

The pumping apparatus comprises generally an outer pressure vessel or barrel l0 having a closed lower ,end and a removable cover plate Hat its upper end, a pump assembly I! suspended from the under side of the cover plate, and anelectric motor I3 suspended from the lower end of the pump assembly and having its rotor operatively connected with the pump impellers. When the cover plate II is attached to the barrel, the latter forms a fluid-tight chamber which is completely sealed except for a suction nozzle I5 and a discharge nozzle l6. In the illustrated embodiment charge llne I8 leading to an ejector mounted in the lower portion of the storage tank B. The ejector forces the liquid from the tank through the suction line 2| andinto'the barrel 10, the latter being thus maintained full of pump liquid at a pressure greater than'the vapor pressure of the pump liquid, and serving as a reservoir in which the suction of the pump is submerged.

'A conductor cable leads from a suitable 'starting' box and control panel. (not shown) to terminals connected to a second pothead section I state that the pump comprises generally an outer casing 3| suspended from the cover plate II by a short section of discharge pipe 32 secured to the cover plate in alignment with the discharge nozzle "Land an axially split inner impeller case r 38 mounted in the outer casing in spaced rela- 'Fig. 6 is a transverse sectional view taken on line 8-6 of Fig. 5;

Fig. 7 is a transverse sectionalview taken on I line 1-1 of Fig. 3;

Fig. 8 is a longitudinal sectional view corresponding to Figs. 3 and3' but showing a modified construction; and

Fig. 9 is a view similar to Fig. 8 a still further modification.

and showing tion to the inner wall of the latter, thus forming an annular discharge spacebetween the casings into which the pump liquidis discharged from the inner case. A plurality of impellers ,34 are rotatably mounted in impeller cavities in the inner case 33. For a detailed description of the construction of the inner case, reference may be had to U. S. Letters Patent No. 1,997,824, to Aladar Hollander, dated April 16, 1935.

A branch fitting is secured to the lower end of the outer casing 3| of the main pump l2. and provides a main discharge passage extending from the auxiliarypump 19 to the suction inlet of the pump l2, and a branch discharge passage 36 communicating with the-nozzle of the ejector 20 through nozzle l1 and pipe I8. It will be observed that. the pump I9 is a single stage deepis approximately 1.4 to 1.

impeller 38, and a suction piece 39. Suspended from the lower extremity of the suction piece is a strainer 49 which establishes communication between the suction inlet of the pump 9 and the interior of the outer barrel It. An adapter H is secured to the lower end of the strainer 49 and has supporting connection at its lower end with the housing 42 of the motor. IS.

The motor I3 is preferably-an oil-filled, pressure-balanced s bmersible motor having a liquid seal, generally d signated '45, sealing the juncture 'of the rotor shaft 46 and the motor housing 42.

The detailed construction of themotor and of the liquid seal may be similarto that disclosed in our Patent No. 2,171,749, dated September 5, 1939, for Submersible motor assembly, although it will be appreciated that considerable variation in the construction of the motor is permissible so long as the essential features of this type of motor are retained. I

As shown most clearly in Fig. 3, the upper end of the rotor shaft is connected in driving relation with the pump shaft 59 by a shaft coupling 5| within the adapter 4!. The pump shaft extends upwardly through the strainer 40; auxiliary pump I9, and impeller case 33 of the double-case pump l2, and has keyed thereto both the impeller 38 of the auxiliary pump and the impellers'34 of the pump l2. The motor l3 thus drives both pumps, and by reason of the branch fitting r the single stage pump l9 performs the dual function of supplying pump liquid to the ejector; 29

in the storage tank 13, and of delivering pump liquid to the first stage of the multistage pump l2 at a positive pressure which is determined by .the back pressure at the ejector nozzle.

The provision ofthe ejector 20- is occasione by the fact that safety regulations require that piping connections between an underground storage tank and an underground dispensing receiver 5 'be connected to the top rather than to the base of the tank and receiver, thusrequiring the pump ,liquid to be elevated a substantial distance while being transferred from the tank to a receiver on the same level as the tank. If the pump'liquid is one having a vapor pressuregreater than atmospheric pressure the tank is maintained closed and the pressure within the tank is normally .the vapor pressure of the liquid. Consequently,'any

in the transfer pipe or due to the higher elevation of the transfer pipe is likely to cause vaporization 60 reduction in pressure resulting from friction loss I of the pump liquid in the transfer pipe. By providing an ejector in the tank, however, the normal pressure of the liquid is increased by an amount at least sufficient to offset the above losses, and

vaporization is avoided.

. It will no doubt occur to those familiar with this art that it would be possible to by-pass a .por-

tion of the discharge from the main pump l2 back to the ejector 20 to accomplish the same Under these condi- I feet.

0n the other hand, if liquid were by-passed seen that a considerable loss of eifi'ciency is entailed by bleeding off a portion of the discharge of a high-pressure pump to operate an ejector when only a relatively low pressure need be developed by the ejector. I

In the instant case, the auxiliary, pump l9 serves a dual purpose- -that of a preliminary stage of the multistage main pump I2, and of supplying actuating liquid to the ejector 20, and hence it must be of greater volume capacity than the main pump. In an actual installation .corresponding to that shown in Figs. 1 to '7 of the accompanying drawings, the loss of head in the ejector discharge pipe 2| is approximately 18 feet, and hence it was necessary to provide an ejector which would develop that pressure while transferring a volume bf pump liquid equal to that delivered by the main pump I2. In order to proximately two and one-half times the pressure.

to be developed by the ejector, or about 45 feet. Under these conditions, with an efficiency of approximately 33%, the volume of actuating liquid delivered by the auxiliary pump [9 to the ejector is approximately 1.4timesthe volume of liquid transferred by the ejector from the-tank to the receiver. In the aforementioned installation the main pump I2 delivered 25 g'allonsperminute against a head of 400 feet, and the auxiliary pump l9 delivered a total volume of 60 gallons per minut e-25 gallons per minute to the suction inlet of the main pump and 35 gallons per minute (25 1.4) to the ejector-against a head of 45 from the discharge of the main pump, at a pres. sure of400 feet, to develop a head of 18 feet in the ejector, the efficiency of the ejector would be of the order 'of 10%, and approximately half the discharge from theomain pump would have to be by-passecl to the ejector. This would require the use of a pump of double the capacity of that in the instant case, and would greatly increase the consumption ofpower since the overseparate pump delivering actuating liquid to the" ejector at-relatively low pressure, material economi es may be effected, both in operating expense and in the size and cost of the equipment. In the instant case, we have provided a simple and effective arrangement whereby the low pressure pump is driven by the same 'shaft that drives the main pump, and also serves as an initial stage of the main pump.

It will be understood that the foregoing figures are cited solely by way of example and to illustrate the manner in which the required capacity and head of the auxiliary pump is ascertained .from a predetermined loss of head in the transfer pipe 2| and a predetermined capacity and head of the main pump.

As stated in the introductory remarks, an important feature of the invention which renders it especially'well adapted to handling butane and 'propane is the complete isolation of. the pump liquid from the dielectric liquid within the motor housing 42. The mercury seal 45 which surrounds the rotor shaft at its juncture with the upper end of the housing effectively separates the two liquids at that point. However, a liquid seal will function in a satisfactory manner only if the pressures on opposite sides of the seal are balanced, thus necessitating a pressure-equalizing liquids.

connection between the two liquids. If the two liquids are immiscible, it has been found that this can be accomplished satisfactorily by the provision of a breather opening in the lower,end of the motor housing establishing communication between the external and internal liquids in a quiescent zone of both liquids. If the pump liquid is miscible with the dielectric, however, it is essential that direct contact between the two liquids be entirely avoided, even in a quiescent zone, in order to prevent intermixing by molecular interchange atthe interface or surface of contact between the two liquids.

In the present instance, the lower end of the motorhousing 42 is in open communication with the outer barrel H], but direct contact between the dielectric liquid in the motor housing and the pump liquid in the barrel is avoided by inter posing a body of a third liquidbetween them. The third liquid maybe any liquid which is immiscible with the pump liquid and the dielectric liquid and which is preferably heavier than both If the pump liquid is a hydrocarbon, such as butane, propane, or gasoline, and the dielectric is a pure crystal oil, as is generally the case, water may be used as the third liquid. If temperatures below the freezing point of water are likely to be encountered, an anti-freeze" solution such as diphenyl glycol may be used instead of water.

Referring to Fig. 3 of the drawings,. the lower portion of the outer barrel l contains water or other suitable intermediate liq gd up to the level indicated at 60. This level is p eferably adjacent point it is connected to a T 63; The leg of the T extends downwardly at 64 and terminates adjacent the lower end of the barrel III in an open A breather or balance tube ii is con- 5 tube is connected at ii to the adapter 4| between the motor housing and the strainer 40,

end of the tube 64 and then upwardly to approximately the level of the T 63. The interior of the.

adapter, which communicates directly. with the outer side of the mercury seal 45 is thus open to the pump liquid in the barrel l0 through a U-tube consisting of piping of the same size and length as the U-tube 6i, 6'4. The frictional resistance to flow of fluid from'the barrel through the U-tube Iii and into the adapter 4| is thus equal to the frictional resistance oflered by the tubes 6!, 64. Consequently, any abrupt change in pressure in the barrel will be communicated through the two U-tubes to the opposite sides of the mercury seal at equal rates. 'If the U-tube 10 were omitted and the interior of the adapter were in direct communication with the pump liquid in the barrel,--any sudden change l-the pressure of the pump liquid would be transmitted to the external side of the mercury seal immediately, while the transmittal of the pressure change to the dielectric liquid in the motor housing and thence to ciently to break the seal.

end immersed in the' body of intermediate liquid.

v the surface of the intermediate liquid at is in direct contact with the pump liquid, the pressure of the latter is communicated directly to the intermediate liquid and through the U-tube to the dielectric liquid. When the motor is idle, the dielectric liquid fills the tube 5| and'the upper portion of the tube 64, the remaining portion of the latter being filled-with intermediate liquid. When the motor is energized its temperature rises causing the dielectric liquid in the motor housing to expand and force intermediate liquid downsult, the seal would be temporarily unbalanced,

possibly resulting in displacing the mercury sufii- Theiprovision of the tube 10, however, avoids the possibility of unbalancing the seal by sudden pressure changes.

In order to establish and maintain the level of'the intermediate liquid at approximately the height indicated at 60, a control line 12 is provided. This line is open at its lower end and extends from a point slightly below the normal level of the intermediate liquid upwardly through the cover plate II to a shut-off valve '13 (Fig. 4). A make-up line may extend from the valve to a source of intermediate liquid (not shown). During operation of the unit, there should be no appreciable change in the level of the intermediate liquid, provided it is immiscible with the pump liquid. However, the level may be checked periodically by opening the valve 13 and allowing the pressure of the pump liquid to force intermediate liquid upwardly through thepipe l2.

' When the level of the intermed ate liquid has been lowered to that of the lower end of the pipe, pump liquid will enter the pipe and may be de'- tected at the point of venting. After having established the level of the intermediate liquid at the ,lower extremity of the pipe T2, a small quantity' of intermediate liquid may be added to raise the level slightly above the end of the pipe, such as to the level indicated at so iii-Fig. 3.

On'oil filler line li is alsoprovided for supplying oil or other dielectric liquid to the interior of the motor housing. This line is preferably connected to the upper end of the motor housing, as at 16. and extends upwardly through the cover plate I I to a shut-off valve 11 (Fig. 4), and thence to a suitable source of dielectric liquid (not shown). q 7

It will be apparent from an inspection of Figs. 3 and 3 that the motor I3 is located in a quiescent body of liquid outside the path of flow of wardly within the tube 64. The expansion of the dielectric liquid occurs at such a slow rate, however, that the pressure balance is not disturbed.

As a further precautionary measure to assure that abrupt changesin the pressure of the pump liquid within the barrel l0, such as may occur when starting or stopping the unit, will not temporarily unbalance the mercury seal, a balance pump liquid through the barrel I0, and hence the main stream of pump liquid cannot be utilized to dissipate the heat generated by the, motor windings. Special means must therefore be provided for cooling the motor. In the present-instance this is accomplished by by-passing asmall amount of pump liquid in heat-exchange relationship with the motor housing. It will be observed that the major portion of the motor hus-' ing is disposed below the level 60 of the intermediate liquid. In order to provide an open system of circulation of pump liquid about the motor housing 'and at the same time avoid intermixing .of the two liquids, a jacket 80 is provided about the motor housing. The lower end of the jacket has fluid-tight engagement with the wall of the housing as by means of packing 8|, and the upper end of the jacket is open and projects a substantial distance above the level 60 of the intermediate liquid, thereby forming an annular channel about the motor housing in open communication with the pump liquid in the outer barrel but sealed off from the intermediate liquid. An annular baffle plate 82 is secured vto the upper extremity of the jacket 80 and bridges the annular space between the motor housing and the inner wall of the outer barrel'lfl at a point a slight distan'ce above the level 60 of the intermediate liquid, to form a barrier against eddy currents in the pump liquid and thereby provide a quiescent zone at the level 60.

Cooling of the motor housing is effected by spraying pump liquid onto the motor housing by its own pressure, and that only a relatively small amount of pump liquid will vaporize within the barrel to maintain the pressure at the vapor pressure of the liquid until it has been blown down to the level of the lower end of the blowoff line. The pump liquid within the annular space between the ballle B2 and the surface 60 of the intermediate liquid may be blown off in its liquid phase by opening the valve I4 and first blowing off intermediate liquid until the level of the latter is reduced to the lower end of the level control line I2, and thereafter pump liquid will be blown from the line I2, If desired, the barrel may be blown down simultaneously through lines I2 and 90 until vapor issued from one line.

Referring now to the electrical connections to the motor I3, it has previously been observed that these connections comprise an outer cable section 25, and inner cable section 28, a pair of outer and over a substantial area thereof from a plurality of perforated pipes 85 suspended from an arcuate header 86 partially surrounding'the motor housing. Pump liquid is supplied to the header through a pipe 81 connected to the pumping unit at any desired point above the single stage pump I9. The branch fitting forms a convenient point from which to by-pass the cooling liquid at one-stage pressure. By this construction a small volume of pump liquid is continually sprayed over in, the pump liquid is maintained at superatmospheric pressure throughout the system not only when the unit is in operation but also while it is idle, and consequently no evaporation of the pump liquid can occur. It may become necessary or desirable, however; to remove the pumping unit from the outer barrel for inspection or repair,

and in such event the pressure within the barrel must obviously be reducedto atmospheric, causing any pump liquid within the barrel to vaporize when the pressure dropsbelow the vapor pressure of the liquid. If the entire volume of pump liquid in the barrel were permitted to vaporize within the barrel, the resulting drop in tempera-- ture would be such as might have a deleterious effect on the equipment, and if water were used as the intermediate liquid it would be frozen.

In the present instance, provision has been made for venting the p mp liquid from the barrel from the lowest level of the pump liquid, thereby enabling the unit to blow itself empty of pump liquid and causing the vaporization of all except a small amount of pump liquid to occur outside the barrel. A blow-off line 90 extends from an external shut-off valve 9| through the cover plate I I and downwardly within the bar-rel and within the cooling jacket 80 and terminates adjacent the bottom of the cooling reservoir formed by-the jacket, as indicated at 92 in Fig. 3.

It will be apparent that upon opening the valve M, the pump liquid will be forced from the barrel

inner pothead sections

26 and 21 interconnecting the two cable sections, and a motor terminal box 29 connecting the inner cable section 28 to the motor housing. As most clearly shown in Figs. 5

and 6, thecover plate I I is provided with a circular opening IOI, which is of sufficient size to permit the insertion of the motor terminal box 29 (Fig. '7) and of the inner pothead section 21 (Fig. 5). Thetwo pothead'sections 26 and 21, which are preferably of'identical construction, are bolted to'opposite sides of a connector plate I02 which in turn is bolted to the outer face of the cover plate I I. In this manner the two cable sections may be secured to their individual pothead sections and the latter may be electrically interconnected and structurally assembled on the connector plate |02 prior to assembly on the cover plate. Thereafter the terminal box 29, inner cable section 28, and inner pothead section 21 may be inserted through the opening IOI in the cover plate and secured in place by bolting the connector plate to the cover plate. The terminalrel, and the foregoing arrangement enables the electrical conductors to be made up as a complete sub-assembly prior to being attached to the pumping unit.

Inasmuch as-the two pothead sections are identical, a detailed description of one will sufllce. As most clearly shown in Fig. 5, the section 26 comprises a hollow cylindrical housing member having a reduced bore I05 at its upper extremity. An adapter sleeve I06 is mounted in the bore I05 with a close sliding fit, and has snug engagement with the cable 25 extending therethrough. By the selection of an adapter sleeve of proper internal diameter, various sizes of cable may be attached to a standard pothead section. The cable is rigidly clamped to the pothead by a clamping member I01 secured to the pothead as by bolts I08 and having formed integral therewith a pair of upstanding arms I09 and a diametrically split clamping sleeve IIO embracing the cable. The two' halves of the sleeve are adapted to be drawn together by bolts, as at III, to thereby grip the cable and secure it firmly to the pothead. A wrapping of soft iron wire H2 is preferably wound about the cable in the region of the clamping sleeve 0, to prevent injury of the outer fabric coating of the cable by the sleeve. Suitable packing H3 is inserted in a packing recess formed by a counterbore in pump liquid. Such a ca screws.

only partially through the connector plate. 'It

- tion of cable under atmospheric pressure.

the upper portion of the pothead, and is compressed by a follower clamping member I01, to seal the joint between the pothead and the adapter sleeve I00. Packing may also be provided between the adapter sleeve and the cable as shown at II5.

The motor I3 in the present instance is of the three-phase inductiontype, and the

cable

25, 28 contains three power conductors I20, I2l, I22, as well as two moto control wire'sJ23, I24 -(Fig. 6). Within the pot ead the individual conductors are separated and each terminates in a socket member I25 adapted Attention is particularly directed to the novel manner in which the terminal plugs are mounted in the pothead. It will be observed that they are cast or molded within a one-piece block I21 of insulating material such' as Bakelite, which is clamped between one of the pothead sections and the connector plate' l02. A sealing ring I28 forms a fluid-tight seal between the insulating block, the pothead section 21, and the connector plate I02. Each of the terminal plugs projects entirely block and terminates at its opposite end in a sleeve Ill formed on the to engage a terminal plug through the insulating plug I26" adapted to engage a socket member I on'the end of each of the conductors of the inner cable section 28, thus electrically connecting the corresponding conductors of the two gable sections.

Inasmuch as the inner cable section 28 is im- -mersed in the pump liquid and subjected to the the outer barrel I0, itis prevailing pressure in desirable that it be pressure-balanced internally and externally. This maybe accomplished by employing a motor terminal box 29 which establishes communication between the interiors of the motor housing and of the cable, thus permitting the dielectric within the motor housing to be forced upwardly within the cable" and exert an internal pressure equal to the pressure of the terminal box is disclosed in detail in applicants aforementioned U. S. Letters Patent No. 2,171,149. I

The manner in which the two pothead.

sections

20 and 21 are secured to opposite sides of the connector plate will be understood by reference to Figs. 4, 5

clearly in Fig. 4, the bolting flange I30 onthe outer pothead section 26 is square in outline,- providing space for four cap screws I3I at the corners thereof engaging tapped holes extending only partially, through the connector plate I02.

and 6. As shownmost 1 Similarly, the inner pothead section is bolted to the under side of the connector plate by four I32 engaging tapped holes extending will be observed from Fig, 6, however, that the with respect to the outer section, whereby the two series of bolt holes are arrangedin staggered relation on the same radius. The two sections are thus secured to the connector plate independently of each other, while at the same time the overall width of the flanges is kept to a minimum and the size of the opening IOI in the cover plate is accordingly small. The connector plate I02 is secured in fluid-tight relation to the coverplate II by capscrews I33.

The pothead assembly described above aflords a simple and effective means terconnecting a section of cable under relatively high internal and external pressure and a secinsulating block I21 forms a fluid-tight partition dividing the interior of the pothead into two separate chambers, and thus enables the removal of the outer pothead section 26 and its connected cable 25 from without venting the interior'of the barrel I0 or otherwise disturbing conditions within the barrel. Furthermore, the cable assembly is secured in fluid-tight relation to the cover plate by only a single joint-that between the connector plate and the cover plate. The possibility of leakage of pump liquid'is thus eliminated.

A pumping unit constructed in accordance with the foregoing description may be aptly termed a "stuihngboxless" pumping unit, inasmuch as an outstandingcharacteristic is the I0 is completely closed, not only during opera-' tion but also while the unit is idle, and is sealed faces, and hence leakage of pump liquid from the barrel is eliminated. The elimination of all seals which are dependent on operation of the unit for their effectiveness ,is of paramount importance when handling highly volatile liquids,

since the pumping unit must be maintained un-- der a pressure at least equal to the vapor pressure of the liquid when the unit is idle.

Of primary importance from an assembly and maintenance standpoint is the fact that the entire pumping unit, including the pump, motor, power cable, and all auxiliary piping is assembled on the cover plate II and is independent of the barrel I0. The latter functions solely as a receiver for alignment between the barrel and. the pumping unit are eliminated. 'To remove the unit from the barrel for inspection or repair, it is merely necessary to remove the bolts from the cover plate II and to. disconnect the flanges on the nozzles I5, then be eration; If it is desired to disconnect the outer section ofv cable 25, this may venting the barrel, by removing the cap screws I6, and I1, and the entire unit may,

I3I securing the outer pothead section 26 to the connector-plate I02.

motor circuit and then open a valve in the discharge line. Inasmuch as the main pump I2 is a centrifugal pump having a definite shut-off head,

. it is not necessary to de-energize the motor before closing the discharge valve. When the motor is shut ofi',. the entire unit remains under pressure, and the barrel I0 remains full of pump liquid .in readiness for subsequent operation.

When the unit is first'installed, the barrel 'I0 is obviously filled with air above the level 00 of the water or other intermediate liquid. Assuming thatthe storage tank B contains a volatile" ,liquid, such as butane or propane, under a pressure greater than the vapor pressure -of the liquid, the valves I40and I in the lines I5 and for electrically in- The.

I1 are first opened to permit pump liquid to flow from the tank B into the barrel I0 and equalize the pressure in the two tanks. The discharge valve (not shown) in the discharge line I0 may then be opened slightly to vent the air from the barrel, and the consequent reduction in pressure in the barrel will cause pump liquid to be forced the connector plate I02 pump liquid, and all problems of raised from the barrel in a single opbe done without into the barrel from the tank and fill the barrel. The unit is then ready for operation.

Although we have shown and described a pumping unit which embodies various control means, it is not to be inferred from this that the unit requires frequent attention. ,On the contraryQthe control lines extending through the cover plate, such as the water level control line 12 and the oil filler line 15 are provided solely as a precautionary measure, in the remote event that the dielectric liquid or the intermediate liquid should require replenishmentdue to loss of one of these liquids through possible faulty construction. If the unit is properly constructed, it is capable of operation for an indefinite period of time without attention.

In the embodiment shown in Figs. 1 to 7, provision has been made for transferring the pump liquid from a storage tank at the same ele-- vation as the pumping unit. In many instances, however, the unit may be connected to an overhead storage vessel, in which case the ejector or other auxiliary transfer means may be dispensed with. In Figs. 8 and 9 we have shown two modifications of the pumping unit previously described, in which the auxiliary transfer pump has been eliminated, and in which the main pump is of a different type from that shown in Fig, 3.

Referring to Fig. 8, it will be observed that the pumping unit shown therein is in most respects substantially-identical with the embodiment previously described, and hence a detailed description thereof is deemed unnecessary. Whereas in Figures 1 to '7 the outer ba'rrel or receiver IO-Yis under the pressure of the pump liquid entering the pump, in Figure 8 the barrel Ill is subjected to the discharge pressure of the pump liquid. The inlet nozzle 15* is connected directly to the balance between the pump liquid and the dielectric liquid within the motor housing, and for enabling the dielectric liquid to expand and contract while maintaining it isolated from the pump liquid, is identical with that shown in Fig. 3, and includes breather tubes 6| and 64 and a U-shaped balance tube |[I connected 'to the adapterhousing 4|. A liquid level control line l2! extends downwardly within the barrel to a point slightly below the level 60 of the intermediate liquid,'and a vent line 90 extends to a point adjacent the base of the cooling jacket 80", and function in the same manner as the corresponding elements in Fig. 3. An oil filler line 15 is connected to the upper portion of the motor housing for replenishing the dielectric liquid if this should become necessary. The electrical connections to the motor are preferably identical with that shown in Figs. 3, 3 and 5, and a description thereof is believed to be unnecessary.

The operation of this unit is similar to that of the previously described embodiment except for the omission of the auxiliary transfer pump, the

suction inlet of the pump I2 and the pump liquid discharges from an outlet I! in the pump casing directly into the barrel Ili from which it is discharged through the discharge nozzle Hi. The pump l2 is, in this case, a single case multistage centrifugal'pump similar to the inner case 33 of the double case pump-l2 of Fig. 3, with the outer casing 3| omitted. In this instance the pump and motor are suspended from .the cover plate II by the suction pipe IS.

The motor I3 of this embodiment may be identical with the motor I3 of Fig. 3, and is provided with acooling jacket 8|) extending downwardly into the water or other intermediate liquid with which the lower portion of the barrel I0 is filled. Suitable perforated cooling pipes 85 are provided for circulating pump liquid over the outer surface of the motor housing, although in this case the direction of flow of cooling liquid will be in a direction opposite to that in Fig. 3. Inasmuch as the pump liquid in the barrel Ill is under discharge pressure, the by-passed cooling liquid iiows downwardly into the jacket 80 and over the surface of the motor casing, and thence mm the perforated pipes 85 through the perforations therein, and thence upwardly through the pipe 81 to, an intermediate stage of. the pump. It is preferable that the pipe 81"- be connected to a pump stage as close as possible to the pump liquid may be drained from theyump through the cooling pipes and into the acket 80 when the unit is vented, and thus avoid vaporizationof any substantial amount of pump pump casing during the venting lower extremity of the pump, in order that the perature conditions, it is advantageous pump liquid in this case being fed to the pump by gravity or by other means independent of the pumping unit. Under some pressure and temgo maintain the outer barrel or receiver under ischarge pressure instead of suction pressure, and in the embodiment shown/in Fig. 8 this is rendered possible "by connecting the suction inlet of the pump directly to the suction nozzle of theouter barrel, and by discharging from the pump into the outer barrel and thence to the discharge nozzle.

. In Figure 9 we have shown a pumping unit embodying the essential features of the two forms previously described, and differing from that shown inJFig. 8 in that the pump liquid enters the outer barrel lO through an inlet nozzle Iii and enters the inlet of the pump li through a strainer 40". A discharge nozzle I6 is connected directly to the discharge of the pump, and it is thus seen that the outer barrel is subjected to the suction pressure ofthe pump liquid as in the embodiment shown in Figs. 1 to 7,

rather than to discharge pressure as in Fig. 8.

The pump shown in Fig. 9 is a multistage centrifugal pump of the deepwell type, comprising a plurality of pump bowls in series. Inasmuch as the motor and'its various auxiliary control devices are identical with that previously described in connection with Figs. 1 to 7, except for the omission of the auxiliary pump for operating the elector, further description thereof is deemed unnecessary.

Although we haveshown and described sevoral-embodiments of the invention, it is to be understood that th invention is not limited to the specific details thereof, and that various modifications may be made therein within the ,spirit of the invention and the scope of the appended claims.

,1. Pumping apparatusparticularly adapted for handling volatile liquids comprising, in combination: a fluid-tight receiver having a pair of pump liquid passages through the wall thereof; pump means mounted in'said receiver and comprising a pump casing having a fluid passage therethrough, one end of which is in communication with one of said pair of passages and the other end of which is in open communication with the interior of said receiver; a pumping element mounted in said pump casing; and a motor a stator, and a housing enclosing the rotor and stator and containing an internal liquid; shafting projecting through a wall of said housing,

andconnecting said rotor in driving relation with said pumping element; a seal for sealing the juncture of said shaiting and said housing; a body ot intermediate liquid in said receiver of greater specific gravity than the pump liquid and said internal liquid and immiscible with both of said liquids, and means for establishing pressure transfer relation between a quiescent zone of saidinternal liquid and saidintermediate liquid, and between a quiescent zone of said pump liquid and said intermediate liquid. LL.

2. Pumping apparatus as set forth in claim 1, in which said means for establishing pressure transfer relation between said intermediate and internal liquids comprises an inverted U-tube.

having oneleg thereof in open communication with 'said intermediate liquid in the lower portion-of the body of intermediate liquid, and having the other leg thereof in open communication 5 with, the interior of said motor housing adjacent the end thereof remote from said projecting shafting. Y

3. Pumpingapparatus as set forth in claim 1, in which said motor housing extends at least partially below the surface of said body of intermediate liquid, and including means for circu- ,lating pump liquid in heat exchange relation with said motor housing below the level of said intermediate liquid, comprising walls extending into said intermediate liquid and defining a chamber about said motor housing, said chamber being isolated from the intermediate liquid and having open communication with the pump liquid, and a by-pass conduit connecting said;

- chamber and the interior of said pump casing.

Q 4. A stuflingboxless pumping apparatus comprising: an elongated fluid-tight vessel having fluid inlet and outlet passages through thefwall thereof adjacent one end thereof a submersible motor pump unit mounted insaid vessel and in cludinga pump and a motor connected thereto; said pump comprising a casing having a fluid passage therethrough, one end of which is in communicationwith one of said fluid passages and the other end of which is in open communication with theiinterior of said vessel whereby pump liquid flows ,through said pump. and through said vessel between the inlet and outlet passages therein, and a pumping element. operable in said casing; said motor comprising a motor housing immersed in the pump liquid in said vessel in a portionthereof removed from the path offlow ofpump liquid through said vessel; stator and rotor elements in said housing, said rotor pumping element; and means for cooling said motor comprising means for circulating cooling fluid in heat exchange'relation with said motor housing at'least in the region of said stator element therein. r

. 5 Pumping apparatus as set fortliin claim 4,

including a jacket surrounding said motor hous-' ing in the region of the stator element therein, said cooling fluid being circulated through said jacket in heat exchange relation with said motor housing. f a e 6. A stufllngboxless pumpingapparatus comprising,,in combination: an elongated fluid-tight i vessel adapted to be mounted in an upright po-v sition and having a closed lower end and inlet and outlet fluid passages formed in the wall thereof adjacent its upper end, a portion of the upper end wall of saidvessel being detachable to afford access to the interior thereof; and a submersible motor-pump unit mounted in said vessel and including a pump and a motor connected thereto; said pump comprising a casing having a fluid passage therethrough, one end of which is in communication with one of said fluid passages and the other end of which is in open communication with the interior 'of said vessel whereby the latter constitutes a receiver for pump liquid; a pumping element operable in said casing; said motor comprising a motor housing immersed in the pump liquid in said vessel and subjected externally to the pressure of thepump liquid, said housing containing an internal liquid different from the pump liquid, motor elements in said housing and including a drivin member extending through a. wall of said housing into driving relation with said pumping element, a seal for sealing the juncture of said driving member and said housing, and means independent of said seal for establishing pressureequalizing relation between'the pump liquid and 1 the internal liquid and thereby balance the pressures on opposite sides of said seal, said lastnamed means being operable in a quiescent zone of both liquids.

'l, A stuflingboxless pumping apparatus comprising a fluid-tight vessel having a pair of fluid passages extending through the wall thereof; and a submersible motor-pump unit mounted within said vessel and including a pump and a motor connected thereto; said pump comprising a pump casing having a fluid passage therethrough, one end of which communicates with one of said fluid passages and the otherend of which is in open communication with the interior of said vessel; apumping element operable in said pump casing; said motor comprising a motor housing immersed in the pump liquid in said vessel and subjected externally to the pressure of the pump liquid and containing a second liquid, motor elements inxsaid housing and including a driving member extending through a, wall of said housing into driving relation with said pumping ele- ,sfor sid flu'd as s; a mtrum unit element connected in driving relation with said a 1 p S age 0 o p p mounted within said vessel and secured to said detachable wall portion" and comprising a pump casing having a fluid passage therethrough, one

end of which is in communication with one of said fluid passages and the other end of which is in open communication with theinterior of said vessel; a pumping element operable in said pump casing; a motor housing connected to said sel and the liquid contained in said motor housing in a quiescent zone; electrical conductor means extending from an external source through said detachable wall portion to said motor; said motor-pump unit and said conductor means being removable from said vessel as a unit with said detachable wall portion.

9. A stufilngboxless pumping apparatus as set forth in claim 8, in which said conductor means comprises an outer conductor cable section extending from an external source to the outer side ner cable section to said motor, and a connector member secured in fluid-tight relation to said detachable wall portion and operatively interconnecting said cable sections, said detachable wall portion having an opening therethrough of a size suflicient to pass said terminal box, whereby said cable sections, terminal box,.\ and connector member may be assembled as a unit prior to securing the unit to said detachable wall portion.

11. A stuffingboxless pumping apparatus as set forth in claim 8, in which said conductor means comprises an outer cable section having an outer pothead section secured to one end thereof, an inner cable section secured at one end to said motor and having an inner pothead section secured to the other end thereof, a connector plate detachably secured in fluid-tight relation to said detachable wall portion, means detachably securing said pothead. sections to opposite sides of said connector plate, and an insulating block clamped between said potheads and having one or more terminal elements extending therethrough and engageable with corresponding conductors in the respective cable sections.

ALADAR HOLLANDER. VAINO A. HOOVER.