US2737120A - Pump and motor combinations - Google Patents

Description

March 6, 1956 A. IVANOFF ET AL 2,737,120

PUMP AND MOTOR COMBINATIONS Fil ed Feb. 12, 1952 5 Sheets-Sheet l March 6, 1956 A. IVANOFF ETAL PUMP AND MOTOR COMBINATIONS 5 Sheets-Sheet 2 Filed Feb. 12, 1952 March 6, 1956 A. lVANOFF ET AL 2,737,120

PUMP AND MOTOR COMBINATIONS Filed Feb. 12, 1952 5 Sheets-Sheet 5 Mm ch 6, 1956 A. IVANOFF ET AL 2,737,120

PUMP AND MOTOR COMBINATIONS Filed Feb. 12, 1952 5 Sheets-Sheet 4 l l b Q ZSO March 6, 1956 A. lVANOFF ET AL 2,737,120

PUMP AND MOTOR COMBINATION-S Filed Feb. 12, 1952 5 Sheets-Sheet 5 eys United States Patent PUMP AND Moron colt innuarloNs Alexander Ivanofi, Victor Ivanoif, and Ralph Edward King, Luton, England, assignors t0 Hayward Tyler and Company Limited, Litton, England, a British company Application February 12, 1952, Serial No. 271,148

13 Claims. ((1103-87) This invention relates to pump and motor combinations and has particular reference to pump and motor combinations in which the pump and motor are enclosed in what is in effect a common casing, and the fluid being pumped has access to the portion of said casing which contains the motor, and the bearings are all within said casing, so that, when the fluid being pumped is of high pressure independently of the action of the pump, the bearings do not have to withstand the high pressure.

One object of the invention is the provision of an improved pump and motor combination of the above character, in which the assembly of the parts is rendered more easy than 1 eretofore.

Another object is the provision of a construction which enables the common casing to be massive and capable of resisting high internal pressures, whereas the parts of the pump and motor which need to be assembled with precision are relatively light, and are not called on to resist high pressures.

Another ob ect is the provision of improved means for maintaining the portion of the fluid which surrounds the motor relatively cool, although the fluid which is passing through the pump is hot.

Another object is the provision of improved means for maintaining clean and free from foreign bodies the portion of the fluid which surrounds the motor, despite the existence of foreign matter in the portion of the fiuid which passes through the pump.

Another object is the provision of improved means whereby, in the case in which subsidiary circulation i-s effected through an outside cooling device and the portion of the common casing which contains the motor, the common casing can at all times be maintained full of the iiuid without danger of unduly hot fluid contacting with the motor.

Other objects and advantages will appear hereinafter.

in order that the invention may be the more clearly understood certain embodiments thereof will now be described, reference being made to the accompanying drawings w ierein:

Figure l is an outside elevation of a pump and motor combination according to the invention.

Figures 2a and 2b together constitute a sectional elevation of said pump and motor combination.

Figure 3 is a fragmentary View to a larger scale of alterna 've to a portion of Figure 2b.

Figure 4 is a similar view to Figure 3 illustrating another alternative.

Figure 5 is a fragmentary view or" a portion of Figure 257.

Figure 6 is a sectional elevation of a part which may be substituted for a part shown in Figure 5.

Figure 7 is a somewhat diagran'nnutic view of an arrangement including the said pump and motor combination and a boiler th ough which the pump is adapted to circulate water.

Figure 8 is .a view to a larger scale of a portion of Figure 7.

Figure 9 is a similar View modification.

Figure 10 is a section on line XX of Figure -9.

Referring first to Figures 1, 2a and 2b the rotor 1a of the motor (see Fig. 2a) and the rotor 2a of the pump (see Fig. 223) are mounted on a common shaft, 3a, 3b and the motor casing A and pump casing C are united, by means or" a reduced neck portion B between them, into what is essentially a single casing, the said common shaft 3a, 3]) running through this reduced neck portion. The liquid which is being pumped, and which flows through the pump casing C, is able to pass through said reduced neck portion B into the motor casing A, and thus the motor, which is a submersible motor, runs in liquid whose pressure is of the same order as that being pumped by the pump. As the pump is used for boiler circulation this pressure may be very high.

in the present arrangement the aforesaid single casing is made in three integral parts, viz. a middle part 4 and tow end parts 5 and 6. The middle part 4 includes the reduced neck portion B together with a relatively small portion of the motor casing A at one end and a relatively small portion of the pump casing C at the other end. One (5) of the end parts, hereinafter called the motorend part, forms the remainder of the motor casing A and the other and part 6, hereinafter called the pump-end part, forms the remainder of the pump casing C. It will be seen that the middle part 4 is in the form of a tubular neck with outwardly flared ends and that the two end parts '5 and 6 are in the form of elongated domes or cup-liite members of any suitable form. These end parts 5 and 6 are bolted by means of bolts 7 and 3 to the outwardly flared ends of the middle part 4 to complete the motor and pump casings. The tubular neck of the middle part is formed externally with annular fins 9 for heat dissipation, since the liquid being pumped may be very hot and it is desirable to keep the motor cool.

The pump inlet 10 and the pump outlet 11 pass through the walls of the pump-end part s, but the pump stator 2b is not mounted directly on said pump-end part 6 but is mounted on the adjacent end of the middle part Said pump stator 2b thus comprises whatis essentially an inner pump casing 12 in which are mounted the stator elements of the pump and in which the rotor elements rotate. This inner pump casing 12 which does not have to support a large pressure difference on the two sides of its walls can be of light construction.

in like manner the motor stator lb is not mounted directly on the motor-end part 5 but is mounted on the adjacent end of the middle part 4. Said motor stator comprises a relatively light shell 13 which encases the stator windings 14, and it is this shell which is mounted on the end of the middle part 4. Liquid flows freely into this shell and also 5. ws freely into the clearance between the outside of said .shell and the inside of the main outer casing, and thus said shell 13, like the inner to Figure 8 showing a pump casing 12, does not withstand pressure difference and can be of light construction.

It will thus be seen that the massive pump-end part 6 and motor-end part 5' merely serve as pressure-resisting covers and can be removed and replaced without interfering with the motor and pump stators or with the common rotating assembly. Thus the necessity for accurate relative positioning of the middle part 4, the pump-end part 6 and the motor-end part 5 is obviated, and, as a result, much of the internal machining is avoided. Also the fitting of the motor and pump is enabled to take place under conditions of easy access, with the motor-end part 5 and the purnp-end part 6 out of the way.

More particularly the middle part 4, at its end which .is bolted to the pump-end part 6, is formed (see Fig. 2b) withan annular ,sleeve like projection 15 which projects into the pump-end part 6 just inside the inner periphery thereof. Near the extremity of said sleeve-like projection 15, so-called piston rings 16 are provided between the outer periphery of said sleeve-like projection and the inner periphery of the pump-end part 6. An alternative possibility would be to use self sealing packing of the kind expanded by the liquid pressure. in either case a liquid-tight seal is constituted. The inner pump casing 12, which is of generally cylindrical form, is formed with an annular flange 17 running circumferentially round its outer periphery about mid way of its length, and this is bolted flush against the extremity of said sleeve-like projection 15. The end of the inner pump casing 12 which extends into said sleeve-like projection 15 is also bolted against an annular shoulder 18 formed in the inner periphery of the middle part 4. This end of said inner pump casing is closed except for a plurality of small holes 19, and thus it permits of a slow flow of liquid from the pump casing through the reduced neck portion to the motor casing as before stated.

It will be seen that the annular flange 17 around the inner pump casing 12, together with the piston rings 16 round the sleeve-like projection 15, separates into two parts the space surrounding said inner pump casing 12.

The inlet 2% to the inner pump casing is at the extremity thereof remote from the middle part 4, and is therefore on one side of said annular flange 17. The outlet 21 from said inner pump casing 12 is near the other end thereof and is therefore on the other side of said annular flange 17. The inlet 16 and outlet 11 to and from the pump-end part pass as before stated through the wall of said pump-end part 6, the inlet 10 being on said one side of the flange 17 and piston rings 16, and the outlet port 11 being on said other side of said flange 17 and piston rings 16. Thus the liquid flows first into said pump-end part by way of said inlet 10, then into the inlet 20 of the inner pump casing, then out of the outlet 21 of said inner pump casing and finally through a port 22 in said sleeve-like projection 15 out of the pump-end part by way of said outlet 11.

The shell 13 of the motor stator (see Fig. 2a) is of generally cylindrical form and has a flange 23 round one end which is bolted to an annular shoulder 24 formed in the inner periphery of said middle part 4. Both ends of said cylindrical shell 13 are sufficiently open to permit liquid to flow through them.

The electrical leads 25 by which the stator windings of the motor are supplied pass through and are anchored in said middle part 4. Owing to the fact that the openings in the wall of said middle part through which said leads are inserted from inside is covered by the motor in its assembled position the conductors 26 leading from the motor to said leads 25 are made relatively long. During assembly the stator 1b is suspended some distance above said middle part 4 (which is located vertically) and the U leads 25 are placed in position in their openings and are fastened, and then the stator 1b is lowered slowly, being at the same time rotated so as to arrange the conductors 26 in a spiral manner within the flared end of said middle part 4 beneath the aforesaid shoulder 24 to which the stator shell 13 is bolted.

Within the neck portion B'of the casing there is pro vided (see Figs. 2b and 5) a sleeve 27 through which the common shaft 3a, 3b passes. This sleeve 27, which is formed with a number of annular vanes 28 to check heat transfer through the liquid from the pump to the motor is loose around the shaft 3a, 3b. At its end nearest the pump it is rigidly secured to the middle part 4. Said sleeve 27 will be more particularly described hereinafter. The shaft 30, 3b runs in two bearings 31 and 32 one of which (31) is mounted in the upper end of the sleeve 27 and the other of which (32) is mounted within the shell 13 of the motor stator at the end remote from the middle parts 4 of the casing (see Fig. 2a). These bearings 31 and 32 are of the tilting pad type and are more particularly described in the specification of co-pending application Serial No. 271,147, filed of even date herewith now Patent No. 2,702,730.

In view of the fact that the pump 2a, 2b and the common casing 4, 5, 6 on the one hand may be manufactured from materials having a different electrochemical potential form the materials used in the construction of the motor 1a, 1b on the other hand, it is desirable to provide electrical insulation between the motor and the remainder of the assembly. Accordingly insulating material 33 (Fig. 2a) is interposed between the aforesaid flange 23 of the shell 13 of the motor stator and the annular shoulder 24 of the middle part 4 of the casing. Insulation 34 must, of course, also be provided round the fastening studs or set screws 35 by which the bolting of said flange 23 to said shoulder 24 is effected.

For the same reason the common shaft 3a, 3b is made in two pieces 3a and 3b (see Fig. 2b), one for the motor and one for the pump, and said two pieces are united by an insulating connection. This connection is a spigot and socket connection, the ends of both shaft pieces being reduced to form spigots 36, 37, and said spigots being inserted into the two ends of a socket sleeve 38 to which they are both fixed. Thus the spigot 37 of one shaft piece (say the pump shaft piece) has an insulating washer 39 slipped over it so as to abut against the shoulder formed at the root end thereof, and an insulating tube 40 is mounted on said spigot so as to abut at one end against said washer, said tube having an interference fit with said spigot. The insulation is then machined on the outside so as to make it concentric with the shaft and to give it the exact dimensions required. The spigot has, at its extremity, a still further reduced and screw threaded portion 41 which projects beyond the insulating tube 40. The socket sleeve 38 is machined with an internal annular flange 42 about mid way of its length projecting inwardly from its inner periphery.

This socket sleeve is heated and slipped over the insulation covered spigot 37 until its end abuts against the said insulating washer 39. This brings the internal annular flange 42 past the extremity of the screw threaded reduced portion 41 of the spigot, and fairly close to, but short of, the shoulder at the root end of said screw threaded reduced portion.

A second insulating washer 43 is now slipped over said screw threadedreduced portion, and a slotted nut 44 is then screwed onto said screw threaded reduced portion and screwed up tight, thereby forcing the socket sleeve hard up against the insulating washer 39. After the nut is screwed up tight, it is fixed to the screw threaded reduced portion by welding at 45.

A diametrical hole is now bored jointly through the socket sleeve 38, the insulating tube 40 and the spigot 37, and a small insulating tube or bush 46 is pressed into this hole. A pin 47 is then pressed through said tube or bush, and the end of said pin is Welded to the socket sleeve 38. Finally the spigot 36 of the motor shaft piece 3:: is inserted into said socket sleeve 38 and is fixed to said socket sleeve by welding at 48. It will be seen that the two shaft pieces are now rigidly secured together but are electrically insulated from each other.

It will be seen that the spigot 37 of the pump shaft piece 3b is not actually integral with said pump shaft piece but is formed on a separate part of specially hardened steel welded at 49 to said pump shaft piece 3b.

Alternatively as in Figure 3 the end of the motor shaft piece 3a could be bored and the corresponding end of the socket sleeve 38 reduced to form a spigot 59, and the end of said motor shaft fitted outside said spigot 50, the two parts being welded together at 51. This has the advantage that the end of the motor shaft could be easily heated and shrunk on the reduced end of the socket sleeve. The lower portion of Figure 3 shows more clearly than Figure 2 the connection of the sleeve 38 to the spigot 37.

In an alternative construction reliance is placed on interference fit between the two portions of the shaft as illustrated in Figure 4. For this purpose an insulating sleeve 52 is first pressed on the motor shaft spigot 36 and reduced by grinding to a small thickness. The pump shaft piece 3b has a hollow socket 53 whose internal diameter is somewhat smaller than the final external diameter of the insulating sleeve 52. The hollow socket 53 is expanded by heating and shrunk on the insulating sleeve 52. An insulating disc may first be placed inside the socket to prevent contact between the end of spigot and the socket. An insulation washer 54 may also be provided between the end of the spigot 36 and the bottom of the socket 53.

It will be appreciated that no electrical connection is established from the motor to the sleeve 27 through the bearing 31, since the tilting pads of said bearing engage with a synthetic resin sleeve on said shaft as described in the aforesaid copending application Serial No. 271,147.

.It may be mentioned that the electrical insulation interposed between the two shaft pieces 3a and 312 also serves to reduce the flow of heat along the shaft from the pump to the hearing within the aforesaid loosely fitting sleeve 27 (which is on the side of the insulation remote from the pump) and to the motor.

The end thrust of the common shaft 3a, 3b is taken by an end thrust bearing 55 (Fig. 2a) of the tilting pad type mounted just above the journal bearing 32, and just above said end thrust bearing 55 is a small impeller 56. By means of this impeller a the liquid in the motor casing A is kept in a continuous state of circulation through an external cooling device, and thus the motor is kept relatively cool. The liquid thus circulated flows from an external cooling device into the top of the motor casing by way of a conduit 57 and then flows through the impeller 56 and down through the stator of the motor into the reduced neck portion B (Figs. 2b and 5) and thence by way of pipe 53 to the external cooling device.

Describing now certain constructional details, the shell 13 of the motor stator (Fig. 2a) has its lower end covered by means of a plate 59 and its upper end covered by means of a plate 6 5. A light inner tube 61 surrounding the common shaft extends between said plates 59 and 69, and thus the shell 13, the plates 59 and 60 and inner tube 61 form an enclosure for the stator windings 14. The plate 59 has holes 62 through it which afford liquid communication to this enclosure and the plate 60 has holes 63 which also afford liquid communication to said enclosure.

The housing of the bearing 32 is mounted in the plate 60 as clearly shown, said housing being formed with a flange 64- which overlies said plate 60.

Mounted on said flange 64 is a disc ring 65 and mounted on said disc ring are the tilting pads 66 of the tilting pad bearing 55. These tilting pads es are located by means of screw pegs-d7 screwed into said disc ring 65.

The rotating element of the tilting pad bearing is constituted by a disc 68 mounted fast on the shaft and having secured on its under surface a layer 69 of synthetic resin material whose under surface makes sliding contact with the tilting pads. This material 69 is made fast by pegs 79. It may be a material of the phenol formaldehyde type.

Mounted on the plate 50 is an annular upright wall 71 surrounding the tilting pad bearing 55, and mounted on the top of this wall is a horizontal plate 72 having a central opening through which passes a nut 73 screwed on the top of the shaft and serving to secure the disc 68 in place. A clearance 74- remains between the nut 73 and the edge of the hole in the plate 72.

The vanes of the impeller 56 are constituted by raised ridges 75 formed on the upper surface of the disc 68, the upper surfaces of which ridges are very closely adjacent the under surface of the plate 72. When the shaft isrotating liquid is drawn from the top of the-casing down through the clearance 74 and is thrown out radially by the vanes 75 into the space within the wall 71 from which it passes down through the holes 63 to the stator windings.

Reverting to the sleeve 27 (Figs. 2b and 5) it is pointed out that if no provision were made to the contrary the rotating shaft passing through said reduced neck portion 3 would set up a considerable agitation of the surrounding water, and this would tend to increase the heat interchange between the hot pump casing C and the cool motor enclosure A. This agitation would be greater when the clearance between the shaft and the surrounding wall of the reduced neck portion B is considerable, and, for structural reasons, it is usually not desirable to reduce this clearance by reducing the inner diameter of said neck portion. The loosely fitting stationary sleeve 27 reduces this heat interchange. As the thickness of the liquid film between said shaft and sleeve is small the centrifugal forces in the liquid film are also small, so that the differential pressures causing circulation are kept at a small value. In addition the amount of liquid involved in the rotation is small which fact also reduces the heat transfer.

The arrangement is such that a slow passage of liquid between the pump and motor casings C and A is possible over the outside of the loosely fitting sleeve 27, but means are provided to impede the circulation in the space surrounding said sleeve and thereby again reduce heat transference.

More particularly the loosely fitting sleeve 27 is formed, at the end which is towards the pump, with a flange 31, and is mounted in place by said flange being bolted by bolts 29 to an annular shoulder formed at the lower end of the reduced neck portion C. At its upper end which is towards the motor, said sleeve 27 is slightly enlarged for reception of the bearing 31 and is formed With longitudinal ribs or flutes 3a) which engage the inner periphery of the reduced neck portion and accurately centre aid sleeve. Throughout the major portion of its length said sleeve is formed with the aforesaid spaced annular vanes 2% in radial planes, the circumferential edges of which are very close to the inner periphery of the reduced neck portion. Small holes 8i are formed through said sleeve close to the aforesaid flange 81.

The reference 82 designates the outlet from the pump rotor. The upper end wall 33 of the pump stator 12 is bolted, by means of bolts 84, to a shoulder formed inside the middle part 4.

Between the top wall 33 of the pump stator and the lower end of the sleeve 27 is a space in which are provided a plurality of spaced disc-shaped baffles 76 mounted on a sleeve 77 which surrounds the shaft with a clearance in between and is welded at its lower end, at 85, to the top of the pump stator. Spacing elements 73 on the sleeve 77 serve to locate the bafiles 76 and the sleeve 77, together with the uppermost spacing element projects into a countersunk space surrounding the shaft in the lower end of the sleeve 27. in this space above the sleeve 77 is a sludge gland 79. The baffies 76 are in accordanc with prior application Serial N 0. 273,147 aforesaid. sludge gland 79 consists of a porous baffle wiicn fits snugly, but not tightly in the countersunk space in the lower end of the sleeve 27. It may consist of woven asbestos or other fibrous material capable of resisting the action of the hot liquid. Tlfi bafile 79 may be kept in place by means of a ring or washer 13% of metal or other solid material, said ring or washer being in turn kept in place by the sleeve 77 together with the uppermost spacing element 78.

The path by which the liquid being pumped is free to flow slowly to the motor may be traced from the outlet 82 of the pump rotor (Fig. 5), through a space 8-6 between the pump rotor and the top wall 83 of the pump stator, then through the clearance space between the shaft and the sleeve 77 to the sludge gland 79, and through said sludge gland to the clearance space between said 7 shaft and the sleeve 27. The path of communication here divides into two, one branch passing up the said clearance space between the shaft and the sleeve 27, through the bearing 31 and into the motor casing A (Fig. 2a), and the other passing through the holes 89 (Fig. 5) into the bottom of the space surrounding the sleeve 27 over the.

circumferential edges of the vanes 28, and between the longitudinal ribs or flutes 30, the openings between which may be restricted at their ends towards the motor, into the motor casing A (Fig. 2a). Owing to the vanes 28 the liquid is divided into substantially stagnant portions between which circulation is impeded.

It will be observed that all the liquid passing from the pump to the motor casing A whether straight through the clearance between the loosely fitting sleeve 27 and the shaft, or through the holes 89 in the sleeve 27 and thence over the outside of said sleeve must pass through the sludge gland 7?. Thus the bearing 31 and the other bearings within the motor casing A are protected from solid foreign matter which may be suspended in the liquid which is being pumped by the pump.

Communication is also effected by way of holes 37 in the top wall of the pump stator to the aforesaid space occupied by the bafiles 76. The bafiles divide the body of liquid in this space into separate compartments and thus heat transfer from the pump towards the motor is reduced.

Within the motor casing (Fig. 2a) the liquid has access through the holes 62 into the enclosure of the stator windings and through the holes 63 and the clearance 74 to the outside of the shell 13. The liquid also clearly has access to the space inside the inner tube 61.

The circulation path through the external cooling device may be traced from said cooling device through the conduit 57 to the top of the motor casing (Fig. 2a), then rough the impeller 56 as before described to the enclosure of the stator windings 14, then through the holes 62 to the outside of the sleeve 27 (Fig. 5) and through the conduit 58 to the cooling device.

Referring to Figure 6, this illustrates an alternative form of loosely fitting sleeve 27. In this alternative some at least of the annular vanes 23 are omitted and the space between the loosely fitting sleeve 27 and the neck portion 13 of the casing is filled completely or in part by a bush 83 made of a material which is a poor conductor of heat as, for instance a heat resisting synthetic resin or carbon or ceramic material. The annular vanes 28 are shown as being employed on the portion of the sleeve 27 towards the hot pump casing and the poor conducting bush 8% round the remaining portion up to the enlarged portion.

Turning now to Figures 7 and 8 the boiler through which the water is pumped comprises a water drum 89 and water tubes 9%. The water flows from the drum 39 by way of a pipe 91 to the inlet to the pump casing and from the outlet of said pump casing it flows through a pipe 92 to and through the tubes 96 back to the drum 39.

The Water being pumped is of course hot, and in order to maintain the Water in the motor casing A relatively cool, the aforesaid subsidiary circulation is effected from the reduced neck portion B by way of pipe 58 to and through a coiled cooling tube 93, and back by way of pipes $4 and 57 to the end of the motor casing A remote from said reduced neck portion. Said coiled cooling tube 93 is shown immersed in a container 595 which is maintained full of cold liquid which continuously flows in by way of a pipe 96 and out by way of a pipe 97. This subsidiary circulation is effected by means of the aforesaid small auxiliary impeller 56 mounted Within the motor casing.

in the present arrangement the pump and motor combination is arranged vertically with the motor end uppermost. In operation the whole of the common casing A, B, C is filled with the water before use, and an air outlet 98 controlled by a cock 99 is provided, either at the highest point of the external cooling circuit or at the top of the motor casing, through which air may be vented during the preliminary filling and also from time to time during operation as will hereinafter more particularly appear.

The level 100 of the water in the drum S9 is above the level 101 of the air outlet 98 by an amount h, and, in the present arrangement the head developed by the auxiliary impeller 56 is sutficiently low to ensure that even when the boiler is cold and therefore not generating pressure there is a pressure above atmospheric at the point of air release 93 even if the pump and motor are running.

in other words, there is a pressure above atomspheric at the point of air release 98, whether the boiler is cold and the motor and pump are not running or whether the boiler is hot and the motor and pump are running, or whether the boiler is cold and the motor and pump are running or whether the boiler is hot and the motor and pump are not running. Thus, in all circumstances, when it is wished to fill the common casing A, B, C with water, either when it is empty or when there is only a little air collected at the top, all that is necessary is to open the air vent by means of the cock 99, whereupon water will run up from the pump casing C to the motor casing A, being replaced in the pump casing by water flowing down from the boiler drum 89. When water commences to flow through the air vent 98, the cock 99 is closed and the motor enclosure is now full.

The head developed by the auxiliary impeller 56 provides that, when air is vented at the air vent 98 during boiler operation, the hot water flowing from the pump casing C to the motor casing A to take its place does not fiow directly to the motor casing, but passes first through the cooling coil 93 and thus cannot damage the motor windings.

Should the rate of air release be accidentally made excessive it may occur that in spite of the above provisions some hot water may enter the motor casing A, without passing first through the cooling coil 93. To guard against carelessness in operating the air release cock 99 a restriction can be placed in the air outlet path, this preferably taking the form of a length of fine bore tubing 102 as best shown in Figure 8. A filter 103 (Fig. 8) which take the form of a porous metal plug can be placed at the inlet to the fine bore tubing 1492 to prevent foreign matter entering it.

As before described, the auxiliary impeller 56 is mounted at the highest point of the motor casing A. Owing to this fact, when air collects in the top of said motor casing the cooling circulation stops.

As a result of that, the temperature of the water in the motor casing commences to rise and there ceases to be a temperature difference between the inlet and the outlet of the cooling coil 93. Either of these effects can be utilised to actuate a warming device. In Figure 7 a thermometer 164 is shown which responds to the temperature in the pipe '58 and may be arranged to actuate an audible device when the temperature rises beyond a given limit.

Figures 9 and 10 illustrate another arrangement for guarding against too rapid a rate of air release from the motor casing A. According to this arrangement, the air release takes place through two air valves 99:: and 99b in series with a length of piping between them, which is of oval or flattened cross section and is resilient and therefore expansible.

The method of operating the air release is to open first the valve 99a nearest the motor casing, allowing some liquid or air to enter the piping 165 between the two valves and thereby expand said piping. The valve 99a is then closed and the other valve 9% is opened Whereupon the piping 1G5 contracts and the air or water is ejected through said valve 9% to the point of release 98. This ensures that the rate of release of air or liquid from the system cannot become excessive.

The procedure is repeated until no further air is released.

In a simplified version of this arrangement ordinary non-expansible piping may be employed in place of the piping m5, the two air release valves 99a and 99b in series being however still used.

An alternative way to achieve the advantage that water will flow into the motor casing 89 under all circumstances upon opening of the air vent is to reverse the direction of flow through the cooling circuit so that the flow leaves the motor at the upper end of the motor casing 89 and re-enters at the reduced neck portion B. This has all the advantages of the arrangement first described except that the hot water flowing from the pump casing C to the motor casing A is not diverted through the cooling circuit 93 but flows direct into the motor casing A. Greater care in operation of the air vent is therefore required.

We claim:

1. A pump and motor combination comprising a massive composite casing including three separate parts, respectively in the form of a motor-end part and a pumpend part, each in the general form of a cup, and a middle part connected between said two end parts to complete said casing, a rotatable shaft within said casing extending through said middle part and into each of said end parts, bearings for said shaft within said casing, a motor within said motor-end part, said motor having a rotor mounted on said shaft and a stator mounted on said casing, a perforated sleeve extending integrally from said middle part into said pump-end part, a pump within said pumpend part and surrounded by said perforated sleeve, said pump having a rotor mounted on said shaft and an inner pump casing for said rotor mounted in sealed relation on the end of said perforated sleeve, means forming an annular seal between the outer end of said perforated sleeve and the inner periphery of said pump end part, pump inlet and pump outlet openings for said inner pump casing, pump inlet and pump outlet ports in the wall of said pump-end part, each for connection to a high pressure external pipe line, said pump inlet opening and said pump inlet port being both on one side of said annular seal, and said pump outlet opening and said pump outlet port being on the other side of said annular seal, and means for directing the fluid being pumped to the whole of said casing.

2. A pump and motor combination comprising a massive casing, a rotatable shaft within said casing, 21 motor within said casing, said motor having a rotor mounted on said shaft and a stator mounted on said casing, a pump Within said casing, said pump having a rotor mounted on said shaft and a relatively light pump casing mounted on said casing, bearings for said shaft including one bearing mounted on said motor stator and another bearing supported from said casing, said shaft consisting of a motor shaft portion and a pump shaft portion, rigidly connected together at a point between said two bearings, insulation isolating said two shaft portions from each other, insulation isolating said motor stator from said casing, pump inlet and pump outlet ports in the wall of said casing each for connection to an external high pressure pipeline, and means for directing the fluid being pumped to the whole of said casing, the pump and easing on the one hand and the motor on the other hand being made from materials having diiferent electro chemical potentials.

3. A pump and motor combination comprising a massive casing consisting of two end portions joined by a reduced neck, a rotatable shaft within said casing extending through said reduced neck and into each of said end portions, bearings for said shaft within said casing, 21 motor within one of said end portions, said motor having a rotor mounted on said shaft and a stator mounted on said casing, a pump within the other end portion, said pump having a rotor mounted on said shaft and a stator rigid with said casing, pump inlet and pump outlet ports in the wall of said last named end portion,

each for connection to an external pipe line of high p'essure, and a sleeve within said reduced neck loosely surrounding said shaft and ri idly mounted on said casing, said shaft and said sleeve defining an annular clearance t-herebetween through which the lluid pumped is free to how from one end portion to the other, and the film of fluid in said annular clearance being of small thickness and relatively free from agitation, whereby the heat transferred through said film from one end portion to the other is small.

A pump and motor combination comprising a massive casing consisting of two end portions joined by a reduced neck, a rotatable shaft within said casing extending through said reduced neck and into each of said end portions, bearings for said shaft within said casing, a motor within one of said end portions, said motor having a rotor mounted on said shaft and a stator mounted on said casing, a pump within the other end portion, said pump having a rotor mounted on said shaft and a stator rigid with said casing, pump inlet and pump outlet ports in the wall of said last named end portion, each for connection to an external pipe line of high pressure, a sleeve within said reduced necl; loosely surrounding said shaft and rigidly mounted on said casing, a plurality of annular vanes mounted in spaced relation on said sleeve and extending around the outside of said sleeve with their edges close to the inner periphery of said reduced neck, said shaft and sleeve defining an annular clearance therebetween through which the fluid pumped is free to flow from one end portion to the other, and the film of fluid in said annular clearance being of small thickness and relatively free from agitation, whereby the heat transferred through said film from one end portion to the other is small, and means admitting fluid being pumped to the outside of said sleeve whereby such fluid is divided by said vanes into a series of relatively stagnant portions.

5. A pump and motor combination comprising a massive casing consisting of two end portions joined by a reduced neck, a rotatable shaft within said casing extending through said reduced neck. and into each of said end portions, bearings for said shaft within said casing, a motor within one of said end portions, said motor having a rotor mounted on said shaft and a stator mounted on said casing, a pump within the other end portion, said pump having a rotor mounted on said shaft and a stator rigid with said casing, a pump inlet and pump outlet ports in the wall of said last named end portion, each for connection to an external pipe line of high pressure, a sleeve within said reduced neck loosely surrounding said shaft and rigidly mounted on sai casing, and a bushing mounted on said sleeve around the outer periph ery thereof with its periphery close to the inner periphery of the reduced neck, said bushing being made of a material which is a poor conductor of heat, said shaft and sleeve defining an annular clearance therebetween through which the fluid pumped is free to tlow from one end portion to the other, and the h m of fluid in said annular clearance being of small thickness and relatively free from agitation, whereby the heat transferred through said film from one end portion to he other is small.

6. A pump and motor combination comprising a massive casing consisting of two end portions joined by a reduced neck, a rotatable shaft within said casing extending through said reduced neck and into each of said end portions, bearings for said shaft within casing, a motor within one of said end portions, said motor having a rotor mounted on said shaft and a stator mounted on said casing, a pump within the other end portion, said pump having a rotor mounted on said shaft arm a stator rigid with said casing, pump inlet and pump outlet ports in the wall of said last named end portion, each for connection to an external pipe line of high pressure, a sleeve within said reduced neck surrounding said shaft in spaced relation thereto and rigidly mounted on said casing, a plurality of annular vanes mounted in spaced relation on said sleeve and extending around the outside of said sleeve with their edges close to the inner periphery of said reduced neck, said shaft and sleeve defining therebetween an annular clearance having inlet and outlet openings through which the fluid pumped is free to flow from one end portion to the other, and the film of fluid in said annular clearance being of small thickness and relatively free from agitation, whereby the heat transferred through said film from one end portion to the other is small, said sleeve being spaced from said casing for a substantial part of its length and defining with said casing a fluid passage having inlet and outlet openings through which the fluid pumped is also free to flow from one end portion to the other, said last-named fiuid being divided by said vanes into a series of relatively stagnant portions.

7. A pump and motor combination comprising a massive casing consisting of two end portions joined by a reduced neck, a rotatable shaft within said casing extending through said reduced neck and into each of said end portions, bearings for said shaft wtihin said casing, a motor within one of said end portions, said motor having a rotor mounted on said shaft and a stator mounted on said casing, a pump Within the other end portion, said pump having a rotor mounted on said shaft and a stator rigid with said casing, a pump inlet and pump outlet ports in the wall of said last named end portion, each for connection to an external pipe line of high pressure, a sleeve within said reduced neck surrounding said shaft in spaced relation to said casing and to said shaft and rigidly mounted on said casing, and a bushing mounted on said sleeve around the outer periphery thereof with its periphery close to the inner periphery of the reduced neck, said bushing being made of a material which is a poor conductor of heat, said shaft and sleeve defining therebetween an annular clearance having inlet and outlet openings through which the fluid pumped is free to flow from one end portion to the other, and the film of fluid in said annular clearance being of small thickness and relatively free from agitation, whereby the heat transferred through said film from one end portion to the other is small, and said sleeve and casing defining therebetween a passage having inlet and outlet openings, and the bushing aforesaid being slightly spaced from said casing and defining therebetween a small clearance so that the fluid pumpe is also free to flow over the outside of said sleeve and said bushing from one end portion to the other.

8. A pump and motor combination comprising a massive casing consisting of two end portions joined by a reduced neck, a rotatable shaft within said casing extending through said reduced neck and into each of said end portions, a motor Within one of said end portions, said motor having a rotor mounted on said shaft and a stator mounted on said casing, a pump within the other end portion, said pump having a rotor mounted on said shaft and a stator rigid with said casing, pump inlet and pump outlet ports in the wall of said last-named end portion, each for connection to an external pipe line of high pressure, a sleeve within said reduced neck loosely surrounding said shaft and defining an annular clearance therebetween, an annular flange formed at the end of said sleeve nearest the pump, means rigidly securing said flange to the casing, projections on the outside of said sleeve at the end nearest said motor engaging the inner periphery of said neck for centering said sleeve, the end of said sleeve nearest said motor being enlarged, and bearings for said shaft within said casing and slightly spaced therefrom, one of said bearings being mounted in the enlarged end of sleeve, the fluid pumped being free to flow through the annular clearance between said shaft and said sleeve and through said hearing from one end portion to the other, and the film of fluid in said annular clearance being of small thickness and relatively free from agitation, "whereby the heat transferred through said film from one end portion to the other is small.

9. A pump and motor combination comprising a massive casing, a rotatable shaft within said casing, a motor within said casing, said motor having a rotor mounted on said shaft and a stator mounted on said casing, a pump Within said casing, said pump having a rotor mounted on said shaft and a stator rigid With said casing, a partition dividing said casing between said pump and said motor, said partition having a hole through which said shaft passes, pump inlet and pump outlet ports in the wall of said casing on the pump side of said partition, each for connection to an external pipe line, bearings for said shaft within said casing on the motor side of said partition, said partition having a recess formed therein around said hole, and filter means in said recess and in communication with the pump rotor outlet, the pumped fluid being adapted to flow from the pump rotor outlet, through said filter means, to the motor side of said partition and having no other path to the motor side of said partition save through said filter means, so that the bearings are protected from any solid foreign matter which may be in said pumped fluid.

10. A pump and motor combination comprising a massive casing, a rotatable shaft within said casing, a motor within said casing, said motor having a rotor mounted on said shaft and a stator mounted on said casing, a pump within said casing, said pump having a rotor rigid with said shaft and a stator mounted on said casing, a partition dividing said casing between said pump and said motor, said partition having a hole through which said shaft passes, pump inlet and pump outlet ports in the wall of said casing on the pump side of said partition, each for connection to an external pipe line, bearings for said shaft within said casing on the motor side of said partition, said partition having a recess formed therein around said hole, and filter means of woven asbestos in said recess and in communication with the pump rotor outlet, the pumped fluid being adapted to flow from the pump rotor outlet, through said filter means, to the motor side of said partition and having no other path to the motor side of said partition save through said filter means, so that the bearings are protected from any solid foreign matter which may be in said pumped fluid.

11. A pump and motor combination comprising a casing consisting of two end portions joined by a reduced neck, a rotatable shaft within said casing extending through said reduced neck and into each of said end portions, a motor within one of said end portions, said motor having a rotor mounted on said shaft and a stator mounted on said casing, a pump within the other end portion, said pump having a rotor mounted on said shaft and a stator rigid with said casing, pump inlet and pump outlet ports in the wall of said last-named end portion each for connection to an external pipe line of high pressure, a sleeve within said reduced neck loosely surrounding said shaft and defining an annular clearance therebetween, an annular flange formed at the end of said sleeve nearest the pump, means rigidly securing said flange to the casing, projections on the outside of said sleeve at the end nearest said motor engaging the inner periphery of said neck for centering said sleeve, the end of said sleeve nearest said motor being enlarged, bearings for said shaft within said casing and slightly spaced therefrom, one of said bearings being mounted in the enlarged end of said sleeve and the other being in the end portion which contains the motor, a counter-sunk recess being formed in the end of the sleeve towards the pump around the bore of said sleeve, and filter means in said counter-sunk recess, the pumped fluid being adapted to flow from the pump rotor outlet, through said filter means, and along the annular clearance between the shaft and the sleeve and through said one bearing into the end portion containing the motor, and having no other path from the pump to said end portion containing the motor, so that said bearings are protected from any solid 13 matter which may be in the pumped fluid, and the film of fluid in said annular clearance being of small thickness and relatively free from agitation, whereby the heat transferred through said film from one end portion to the other is small.

12. A pump and motor combination comprising a massive casing, a rotatable shaft within said casing, a motor within said casing, said motor having a rotor mounted on said shaft and a stator mounted in said casing, a pump within said casing, said pump having a rotor mounted on said shaft and a stator rigid with said casing, bearing means for said shaft within said casing, pump inlet and pump outlet ports in the wall of said casing adapted to admit and discharge a high pressure liquid, means for directing the liquid passing through said pump throughout the whole of said casing, said pump and motor combination being positioned with said shaft upright, an air outlet at the upper end of said casing, means for opening and closing said air outlet, whereby, by opening said air outlet any air in the casing will escape and liquid will flow into said casing and fill said casing up to the level of said air outlet, said air outlet comprising a fine bore tube through which the escaping air from the casing passes, a filter located between said casing and the inlet end of said fine bore tube, and a cock located between said casing and said filter whereby under control of said cock said air is permitted to flow at will through said cock, said filter and said fine bore tube in series.

13. A pump and motor combination comprising a massive casing, a rotatable shaft within said casing, a motor within said casing, said motor having a rotor mounted on said shaft and a stator mounted in said casing, a pump within said casing, said pump having a rotor mounted on said shaft and a stator rigid with said casing, bearing means for said shaft within said casing, pump inlet and pump outlet ports in the wall of said casing adapted to admit and discharge a high pressure liquid, means for directing the liquid passing through said pump throughout the whole of said casing, said pump and motor combination being positioned with said shaft upright, an air outlet at the upper end of said casing, means for opening and closing said air outlet, whereby, by opening said air outlet any air in the casing will escape and liquid will fiow into said casing and fill said casing up to the level of said air outlet, said air outlet comprising a conduit leading from said casing to atmosphere, and two cocks at spaced intervals along said conduit for controlling flow of air therethrough, a portion of said conduit between said cocks being resiliently expansible.

eferences Cited in the file of this patent UNITED STATES PATENTS 2,241,966 Smith May 13, 1941 2,301,063 McConaghy Nov. 3, 1942 2,461,821 Howard et a1 Feb. 15, 1949 2,514,865 Hornschuck July 11, 1950 2,593,547 Ivanofi May 27, 1952 FOREIGN PATENTS 544,930 Great Britain May 4, 1942 623,874 Great Britain May 24, 1949

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