US2598547A - Pumping of fluids under high pressures - Google Patents

Description

May 27, 1952 A. IVANOFF 2,593,547

PUMPING 0F FLUIDS UNDER HIGH PRESSURES Filed Dec. 16, 1947 2 SHEETSSHEET 1 May 27, 1952 [VANQFF 2,598,547

PUMPING OF FLUIDS UNDER HIGH PRESSURES Filed Dec. 16, 1947 2 SHEETS--SHEET 2 Inventor.

Patented May 27, 1952 UNITED STATES PATENT OFFICE.

PUMPING F FLUIDS UNDER; HIGH PRESSURES Application December 16, 1947, Serial No. 79230? In'Great' Britain Novemb'erll, 1940' Section l Public Law 690,, August 8,, 1946 Patent expires November 11,, 1960 (C1. lim -87) Claims.- 1'

This invention relates to systems comprising a pump driven by an electric m'otorandin which the fluid being pumped is, independently of the action of th pump, of high pressure relative to the ambient pressure surrounding the pumpca'sing. In such systems, Whether thefluid' is a liquid, vapour or gas, much trouble is experienced with the stumng boxes or the like for the transmission between the motor and the pump, owing both to thesaid high-pressureand, in some cases, to the high speed of rotation.

The present invention has for its object the provision of means for obviating these difficulties and in accordanc with the invention the electric motor which drives the pump is itself immersedin fluid contained in what is in effect a part of extension of the pump casing and whose pressure is the same, or is of the same order, as the pressure of said fluid being pumped, so that the" transmission between said motor and said pump does not require any bearing, stuffing box or the like, capable of withstandinghighdifferential pressure on its two'sides.

In order that the invention may "be the more clearly understood an arrangement in accordance therewith willnow he described, reference being made to the accompanying drawings, in which:

Figure: l is a sectional elevation of said arrangem'ent',

Figure 2 is a fragment oi' 'Figure I shown on a larger scale,

Fig. 3 is a diagrammatic view illustrating the application of the arrangement to the circulation of steam, irra Loefiler boiler.

Referringto these drawings, the rotor" la of" an electric motor of the wet type-and the impeller 2301* a; centrifugal pump-are mounted on a common. vertical shaft; 3 and, together with said shaftand': the-stator Irb of'said motor; are-enclosed within.-. a common casing 4', the saidimpeller being mounted atthe lower extremity of said shaft an'cl'v being adapted to draw the: fluid-in radially through an inlet'conduit' 5 at the lower end or:- the. casing: and deliver it radially through anioutlet .6 in theplane ofsaid impeller. Said shaft Isis mounted in two. journal livearings' T and 8,. the journali bearing 1 beingi between the im pelletv and the motor and the journal 'bearingfl heingiatlthe-opposite side of 'saidmoto'r". A's-shown the journal hearing 1" ms closeiy'ina. reduced neck: 4a: of the casing 4- so that free fluid conimunicationbetween the impeller' and the motor is prevented,. though seepage Of the fluid .2 special bush 9', fitting lose on the shaft, may also be mounted in the reduced neck 4a of the casing between the bearing 1 and the impeller 2. As the casing-4 is full of fluid, which will be of the :same pressure as thatof the pump inlet, there will be no great tendency'for the fluid to pass through this bush 9 and "bearing 1, and usually it will be of no consequence if a certain amount does so.

The invention may be used in connection with the circulation of Water in forced circulation boilers-,"su'ch for instance as the La Mont type. In this case the pump is inserted inthe circuit formed by the boiler tubes, so that both the inlet and the outlet are under full boiler pressure, which may range from four hundred to one thousand-Tom hundred lbs. per square inch, while the differential pressure given by the pump is about thirty-five lbs. per square inch. The pressure on both sides ofthe'red'uced neck 4a of the casing- 4 will be: equal and oi the same order as the iul l'b-oiler pressure.

The-invention could also be used connection with Loeffler' boilers where steam iscirculated instead of' water. In this case the device would preferably" he arranged the opposite way to that with the motor at the lower end, and the casing E would he filled water to a level say miuway up the bush 9 Such a schemei's illustrated Figure 8 in which the reference designatesthe boiler drum of the Loefiier boiler. and the reference 36 the steam: superheaters. The boiler drum 35 is connected by a pipe 3T-to the-"pump inlet 5, and the pump outlet 6 is conheated by a pipe- 38 to the inlet of the super heaters 38. The outlet of the superheatersis connected by pipes and v 40 to the inlet of the boiler-drum 35, The main pipe line 4'1 to the point of use extends from the junctionof pipes 39 and 4t; Thus, in the Wei-known way, steam is; circulated from the boiler drum 35 through the superheatersefi an d back tov said boiler drum (where itevaporates more water), a proportion or the superheated-steam flowing to the point of use. The broken=line fl-42 designates the water level in the casing t. V

Again the: device could be used for pumping such productsas hot oil in oil refmer-ies where high pressures are also frequently employed, or it'm'ay" be used for pumping liquefied gas where a pressure musthe maintained to keep the product liquid.

The journal hearing 1 is constituted by'a metal sleeve- Ta fitting" within the reduced neck 411; of

the casing, "said-"sleeve acme: mtecenyrecessed for the reception of a filling of white metal lb forming the actual bearing surface which bears on the surface of a metal tube 3a rigid on the shaft. In the arrangement shown the additional sleeve 9 is constituted as an extension of the sleeve Ia, this additional sleeve making a very narrow clearance with the metal tube 3a.

In the arrangement shown the motor is of the type employing a squirrel cage rotor Ia and having the individual Wires of the winding of the stator lb covered with insulation impervious to the fluid within the casing 4. In the arrangement shown the stator is mounted within a sleeve member I I fitting within the casing 4.

The journal bearing 8 is constituted by a metal sleeve 8a interiorly recessed for the reception of a filling of white metal 8b forming the bearing surface which bears on the surface of a metal tube 31: rigid on the shaft. Said sleeve 8a is formed by a downward extension of a disc shaped part 80 mounted on the upper end of the body portion of the casing 4 as shown. The head 34 of the casing 4 is mounted on the top of said body portion above said part 80 as shown.

To prevent undue temperature rise owing either to flow of heat from the pump or to heat generated by the motor, means are provided for cooling the fluid within the casing. In the arrangement illustrated, this is done by circulating the fluid in the casing from the upper end of said casing through a coil I2 immersed in a cooling tank and back to the lower end of said casing. Thus a small centrifugal impeller I3 is mounted on the shaft 3 in a recess I4 in the head 34 of the casing 4, which recess constitutes the impeller housing, and said impeller delivers the fluid from said recess l4, through a conduit IS in the head of the casing 4, and thence through the coil [2 to a conduit l6 through the wall of the reduced neck 4a of the casing. From this conduit IS the fluid flows through a narrow annular clearance I! formed as shown between the major portion of the inner surface of said neck 4a and the outer surface of the sleeve 1a, 9, and from this clearance it flows through-a ring of holes 18 through said sleeve, between the parts la and 9, to the surface of the tube 3a. It then flows upwards between the bearing surfaces 3a, lb to the upper end of the bearing 1, and from there it flows from the lower to the upper end of the motor, in part between the rotor la and the stator lb, and in part through holes [9 in the sleeve member II to an annular clearance 20 formed between the major portion of the outer surface of said sleeve member and the inner surface of the casing 4, and from the upper end of this annular clearance through vertical slots 2| in said sleeve member. From the space at the upper end of the motor the fluid flows through holes 22 in the disc-shaped part 80 and thence between posts 23 integral with said disc shaped part, and through a ring 24 integral with and supported by said posts, back to the impeller I3. As shown, flow round the outer periphery of the ring 24 is substantially prevented by a surrounding part of the head. of the casing.

It will be seen that, by circulating the fluid in this way, not only is the motor cooled but also the bearings I and B. Adequate lubrication of the bearing 1 by the circulating fluid is also ensured. The bearing 8 will also be sufliciently lubricated by the fluid in the casing.

It will be appreciated, furthermore, that the flow of heat from the pump to the motor is also kept down by the provision of the reduced neck 4a. The heat has to pass by conduction along this reduced neck and the bearing elements within it, and, as said neck is exposedto atmospheric air, much of the heat is dissipated.

In the construction shown, it will be seen that the whole rotating unit comprising the shaft, rotor and impeller is supported by the engagement of a bearing flange 25, which is rigid with the upper end of the shaft, on a ring of suitable bearing material 25 mounted in a recess in the upper surface of the head of the casing 4. A cover member 21 mounted on the head 34 of the casing, is provided for enclosing these bearing parts and the upper end of the shaft.

This cover member 21 has a central port 28 through it which is normally closed by means of a valve 29. This port and valve are to enable air to escape when the casing 4 is being filled with fluid from below, which is usually done by simply introducing high pressure liquid to the pump which will seep up rapidly between the bearing surfaces and through the paths heretofore traced in connection with the circulation of liquid for cooling purposes. To enable the escaping air to reach the port 28 holes may be provided through the bearing flange 25 or the ring 26. The casing is filled up completely to a level above the bearing flange 25 and thus this bearing is lubricated by the fluid in the casing.

Owing to the high working pressure of the fluid within the casing 4 some difficulty has been experienced, in introducing into said casing, the conductors to the stator windings. In the present arrangement this has been overcome by providing each conductor, at the region where it passes to the outside of the casing, with an enlarged flange 30 which is pressed, by the pressure within said casing, against a shoulder 3| formed in the outlet passage through which the conductor passes, thereby forming a seal. In practice this enlarged flange 30 is formed on a separate length of metal which is connected at its two ends to the conductor ends inside and outside the casing. The whole of course is covered by the insulation, which actually provides the sealing surface. The said outlet passage is formed in a bush 32 screwed into the wall of the casing 4. The part 33 is simply a locating bush for the conductor, and is screwed into the larger or inner end of the outlet passage through the bush 32.

All other constructional details are deemed clear from the drawing.

I claim:

1. A liquid pumping system comprising a rotary pump impeller, a pump casing for said impeller, an electric motor having a rotor, a motor casing for said motor, said pump casing and motor casing forming parts of a common casing and having means for establishing liquid communication between said pump casing and said motor casing, a shaft for said impeller and said motor and on which said impeller and motor rotor are mounted, whereby said motor drives said impeller, a bearing for said shaft between said pump and said motor, said impeller impelling liquid through said pump casing and said motor being immersed in liquid in said motor casing whose pressure, owing to the liquid communication within said common casing is of the same order as that of said liquid being impelled, a cooling device externally of said common casing and operatively connected at one end with the motor casing and at its opposite end with the common casing in the regionof said bearing, and means for circulating liquid from said motor casing through said cooling device, for cooling said liquid, and back into said common casing at the region of said bearing, and thereby cooling said motor and said bearing.

2. A liquid pumping system, comprising a rotary pump impeller, a pump casing for said impeller, an electric motor having a rotor, a motor casing for said motor, a reduced neck joining said pump casing and said motor casing and constituting, together with said pump casing and said motor casing a common casing, means within said common casing for establishing liquid communication between said pump casing and said motor casing, a shaft for said impeller and said motor and on which said impeller and motor rotor are mounted, whereby said motor drives said impeller, a bearing for said shaft within said reduced neck, said impeller impelling liquid through said pump casing, and said motor being immersed in liquid in said motor casing whose pressure, owing to the liquid communication within said common casing, is of the same order as that of said liquid being impelled, a cooling device externally of said common casing and operatively connected at one end with the motor casing and at its op posite end with the reduced neck aforesaid, and means for circulating liquid from said motor casing through said cooling device, for cooling said liquid, and back into said reduced neck, and thereby cooling said motor and said bearing.

3. A liquid pumping system as defined in claim 2, wherein said reduced neck is exposed to air for cooling.

4. A liquid pumping system, comprising a rotary pump impeller, a pump casing for said impeller, an electric motor having a rotor, a motor casing for said motor, a reduced neck and constituting, together with said pump casing and said motor casing a common casing and having means for establishing within the same liquid communication between said pump casing and said motor casing, a shaft for said impeller and said motor and on which said impeller and motor rotor are mounted, whereby said motor drives said impeller, a bearing for said shaft Within said reduced neck, said impeller impelling liquid through said pump casing, and said motor being immersed in liquid in said motor casing whose pressure, owing to the liquid communication within said common casing, is of the same order as that of said liquid being impelled, a cooling device externally of said common casing, a conduit connecting said motor casing to said cooling device, another conduit connecting said reduced neck to said cooling device, and means for circulating liquid from the common casing through one of said conduits to said cooling device and back through the other conduit to said common casing, whereby both said motor and said hearing are cooled.

5. A liquid pumping system comprising a rotary pump impeller, a pump casing for said impeller, an electric motor having a rotor, a motor casing for said motor, said pump casing and motor casing forming parts of a common casing and having means for establishing within the same liquid communication between said pump casing and said motor casing, a shaft for said impeller and said motor and on which said impeller and motor rotor are mounted, whereby said motor drives said impeller, a bearing for said shaft between said pump and said motor, said impeller impelling liquid through said pump casing, and said motor being immersed in liquid in said motor casing whose pressure, owing to the liquid communication within said common casing is of the same order as that of said liquid being impelled, a cooling device externally of said common casing and operatively connected at its opposite ends to the common casing, and means for circulating liquid from said motor casing through said cooling device and back into said motor casing.

ALEXANDER IVANOFF.

REFERENCES CITED The following references are of record in the joining said pump casing and said motor casing file of this patent:

UNITED STATES PATENTS Number Name Date 1,347,732 Cooper July 27, 1920 1,377,326 Durnford May 10, 1921 1,736,002 Frickey et al. Nov. 19, 1929 1,897,784 Apple Feb. 14, 1933 1,974,183 Gunderson Sept. 18, 1934 1,974,678 Lafont Sept. 25, 1934 2,243,208 Hawley, Jr. May 27, 1941 2,283,117 Arutonofl May 12, 1942 2,520,880 Harlamoff Aug. 29, 1950

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