US2125041A - Pump - Google Patents

Description

y 1933- I A. A. AlDRlDGE 2,125,041

, PUMP Filed May 20, 1937 t s Sheets-Shefl W ATTORNEY.

July 26, 1938. v A. A. ALDRID GE I 2,125,041

I PUMP I Filed May 20, 1957 3 Sheets-Sheet 2 7/444 ATTORNEY.

A. AQA

' PUMP s sheets-sheet 5 Filed May 1957 M NVENT BY M4 ATTQRNEY.

CV4 1 w N Patented July 26, 1938 PATENT OFFIGE PUMP Arthur A. Aldridge, Pittsburgh, Pa., assignor of one-half to Roy G. Dorrance, Pittsburgh, Pa.

Application May 20, 1937, Serial No. 143,720

17 Claims.

This invention may be advantageously applied to apparatus for evacuating or compressing a gas or apparatus for performing both functions, such as may be applied in the art of refrigeration.

The majority of pumps in the refrigerator art of today are either rotary orreci-procating pumps of the displacement type. A pump of this character is provided with slidable engaging parts which create friction and cause Wearing of the vital sealing parts and tend to limit the extent of their usefulness.

Again pumps of this character are difficult to start under load. One method of overcoming this difiiculty is to provide the pump with fluid by-pass channels which permit the pump to take on the load gradually until it assumes the full pumping load. Full load starting windings for electric motors have also been employed to permit the pump to instantly assume the full pumping load. However installations of such character are intricate and require the use of additional energy which decreases the over-all efiiciency and are therefore undesirable.

The principal object of this invention is the provision of a fluid pump that may be started under full load when impelled by the simplest type of prime mover without undue loading of the same and without the requirement of a regulator for by-passing a portion of the .pumping load.

Another object of this invention is the provision of a fluid pump that is not capable of overloading its propelling means.

Another object is the provision of a fluidpump having a limited capacity for developing a given pressure and the output of said pump becoming less effective as the system approaches said pressure, the output being nil when {the pressure is 7 reached, thus producing a state of static bal- In the drawings practical embodiments are shown to illustrate the principles of this invention.

Fig. 1 is a vertical section of the pump comprising this invention together with a motor for 5 operating the same.

' Fig. 2 is a horizontal section of the pump rotor taken on the line 2-2 of Fig. 1.

Fig. 3 is a side elevation of the pump rotor. shown in Fig. 1.

Fig. 4 is a vertical section showing the application of the pump rotor within the motor rotor.

Fig. 5 is a horizontal section of the pump rotor taken on the line 55 of Fig. 4.

Fig. 6 is a vertical section showing a modified form of the relative position of the parts in the pump comprising this invention.

Referring to Figs. 1, 2 and 3 of the drawings, It] represents the pump housing casting which comprises the cylindrical wall II, the bottom wall I 2, and the base 13 which may be flanged as! shown and provided with holes for resiliently mounting the device by any suitable fastening means. Interiorly of the housing the pump i4 is preferably concentrically positioned with the wall II and held in spaced relation thereto by means of the webs I5. The pump stator l4 and the webs l5 may comprise separate parts of the apparatus or they may form an integral casting with the housing ID as indicated on the drawings. The space I6 surrounding the pump stator I4 provides a well or reservoir wherein the oil or other suitable gas impeller liquid is stored.

The bottom of the pump stator I4 is shown integral with the base 12 of the housing In and is 3 provided with the impeller liquid passageway [1 which connects the reservoir 16 with the valve chamber l8. I9 represents a port adjacent the valve chamber l8 which may be circumferentially extended to determine the timing of the rotary valve 20. 21 represents the gas inlet passageway which in this instance is disposed diametrically opposite the passageway 11. However, this passageway may be angularly disposed in a horizontal plane with respect to the passageway l1 to facilitate the timing of the admission of gas with respect to the admission of liquid. The port 22 on the inner end of the passageway 2| may also be circumferentially extended-in the same manner as the port l9.

The valve 20 is cylindrical in shape and arranged to rotate within the valve chamber l8. The wall of the valve is provided with the valve opening 23 which is disposed in the same plane as the ports l9 and 22. The extent of the circumferential valve opening is limited to prevent both ports 19 and 22 from being open at the same time.

An internal gear 24 is cut in the surface of the lower part of the inner circumferential surface of the cylindrical valve. This gear is arranged to mesh with the planet gears 25 supported on the stud bolts 26 which are screwed in the bottom l2 of the housing It. 21 represents the sun gear which is cut in the surface of the lower end of the rotor shaft 28. Thus the ratio of these gears determine the relative speed of the rotary valve 20 with respect to the shaft 28 and the pump rotor secured thereto. The end of the shaft 28 may be supported by the antifrictional thrust bearing 29 which is set in a well in the bottom H2.

The lower edge of the valve 20 may be supported by the antifrictional thrust bearing 38, the lower race of which is embedded in the bottom l2 of the housing. The upper edge of the valve 20 may also be provided with the thrust bearing 3! for assisting in rotatably supporting the pump rotor 32. The rotary valve Zil is thus held from longitudinal movement between the pump rotor and the housing.

The pump stator M is provided with a smooth interior wall and the bottom is provided with a circumferential well 33 which opens to the main reservoir as indicated on the drawings. Thus the liquid in the well 33 is exposed to the bottom of the rotor 32 andthe gas pressure developed by the pump is exposed to the upper surface of the rotor as well as to the upper surface of the liquid in the reservoir IS. The pressure of the gas thus effective on the surface of the liquid is transmitted therethrough to the liquid within the well 33, thereby producing an upward pressure against the bottom of the rotor which pressure is equalized by the same pressure effective over an equivalent area on the top of the rotor.

The pump rotor 32 is constructed to combine two principles in the art of pumping, namely,

. race of the thrust'bearing 3|.

s the valve chamber the centrifugal and the screw.

"The bottom of the pump rotor 32 is f'rustoconical in shape as indicated at 34, the lower end of which is stepped to receive the upper The base of the frusto-conical section terminates in the face of the radial flange 35, which extends to the inner wall of the pump stator l4 and in effect closes the circumferential lubricant well 33. The outer perimetral surface of the flange 35 is provided with the labyrinth groove 36 which aids in sea]- ing the fluid pumped from the well 33. The mating surfaces between the rotary and stationary parts, which may be defined by the rotary valve, the conical and radial undersurface f the pump rotor and the pump stator, act as a pump causing the liquid to flow to the well 33 which is below the surface of the liquid in the reservoir. ."If the resulting pressure in the well 33 is greater than the pressure produced by the centrifugal stage of the pump rotor the liquid will flow past the labyrinth groove. However the pressure on the liquid entrapped therebetween provides a buoyant effect on the pump rotor.

The centrifugal pump section of the pump rotor is formed'in the'lower portionthereof wherein 31 represents the vortex chamber of the pump rotor which is open to the central portion of It. 38 represents radially disposed passageways extending from the vortex chamber to the perimetral surface of the pump rotor just above the flange 35. These passageways are shownto extend tangentially from the center of the vortex space between the shaft and the outer periphery of the vortex chamber and may be formed to have a decreasing cross sectional area from the vortex chamber to the periphery of the pump rotor. These passageways may be straight and extend radially from the axis of the shaft or they may be arcuately formed as taught by the centrifugal pump art, some forms of which are illustrated on the drawings.

The rotary screw section of the pump rotor is positioned just above the peripheral openings of the centrifugal passageways 38 on the peripheral surface 39 of the pump rotor wherein it represents a spiral screw thread which is preferably of the helical type and which may increase in width as it winds up around the increasing diameter of the perimetral surface of the pump rotor. The peripheral surface of the screw thread 48 is in close proximity with the inner wall of the pump stator i4.

Since the interior wall of the pump stator 14 is cylindrical and the peripheral surface 39 of the pump rotor is conical, and since the screw thread 4!] widens as it extends upwardly to the top of the pump rotor, the spiral space or thread trough M bounded by these elements gradually becomes smaller as it approaches the top of the pump rotor, where it opens to the upper part of the reservoir l6. When alternate slugs of liquid and gas are propelled through these passageways which are constantly decreasing in cross sectional area the gas slugs are compressed and the continuous movement of the oil slugs create a vacuum in the vortex chamber.

The pump rotor 32 is keyed to the shaft 28, as indicated at 42, and locked in place by the nuts 43 which force the tapered shaft bore of the pump rotor on the tapered section of the shaft 28.

44 represents the housing cap which forms a closure member for the housing i8 and carries the spaced aligned shaft bearings 45'and 46 within the bearing chamber and also supports the prime mover which in this instance is represented by the simple squirrel cage induction motor 41.

The cap 44 is provided with the pump outlet passageway 48} which permits the exhaust of the gas compressed by the pump from within the space 49 above the reservoir I6.

50 represents a rotary seal which rides on the seat and is resiliently held thereagainst by the spiral seal spring 52 surrounding the shaft 28 and abutting against the under side of the bearing retainer 53 which carries the upper bearing 46. 54 represents a felt oil retainer which rests on the top of the bearing 46 and is held in place by the cap 55.

56 represents the motor rotor which is secured to the upper end of the shaft 28. The motor stator 51 is arranged to be supported on the seat-5B adjacent the top of the upstanding wall 59 of the cap 44. Shims 53 may be provided on the seat 58 to permit vertical adjustment of the motor stator 51 for properly aligning the same with the magnetic field that it creates with the motor rotor 56, thereby preventing the rotor from shifting longitudinally of the axis of the shaft when the motor is energized.

6| represents a check valve which is made up as a separate unit and is secured to the mouth of the intake opening '2-l. This check valve permits the flow of the gas being pumped into the passage 2| when a suction is created therein but prevents the return of the gas when the vacuum is low or pressure is present in the intake passageway 21.

In the structure illustrated in Figs. 4 and 5 the pump rotor and stator are built into one unit and form an integral part of the motor rotor. The motor stator is within the reservoir which holds the gas impeller liquid and the com-' pressed gas.

The motor rotor 58 is made up of a shell member 62 comprising the base portion 63 and the cylindrical wall portion '64. The pump rotor 32 is secured within the shell member and the perimetral surface of the screws 4|] engage the interior surface wall '64. Thus the shell member 62 and the pump rotor 32 are fixed relative to one another and rotate as a .unit. 65 represents a cap plate which forms a closure for the pump rotor and which is provided with a plurality of arcuate slots 66 permitting the discharge from the top of the screw pumping threads '40. The base 83 and the plate 65 extend radially beyond the cylindrical wall 64 and provide flanges between which the laminations of the motor rotor are clamped.

The rotary valve 20 may be secured to the lower end of the shaft 28 with a left hand thread. In this design the valve 20 is arranged to rotate with the shaft and the rotor.

Thus the direction of rotation of the motor, which is counterclockwise in Fig. 5, tends to maintain the valve member on the shaft and holds it tightly against the tapered surface of the shaft 28 above the threaded end. Again the upper end of the valve 20 may be welded or otherwise secured to the shell 62, thereby eliminating a seal and providing one integral rotary unit as indicated at 62'.

The valve 20 is made conical in shape to permit the fluid pumped to have access to the vortex chamber as near to the center as practical. The conical valve also provides a mating engaging surface that is conducive to sealing.

The surface of the valve members 28 opposite the port 23 may be provided with spiral grooves 15 for the purpose of lubricating the engaging parts and the lower thrust bearing which supports the shaft 28.

The passageways 38 as shown in Fig. 5 extend radially from the vortex chamber 31 in an armate path and are reduced in cross sectional area as they approach the periphery of the pump rotor.

51 represents a deflector plate which is bowlshaped and is arranged to receive the fluid discharged from the opposite sides of the pump rotor and throw the liquid to the wall H of the casing, thereby separating the liquid and the gas from the emulsion formed by the pump. The outwardly and downwardly extending perimetral lip 68 of the deflector plate 61 is formed to pre vent any liquid that may be lodged thereon at low motor speeds from descending into the interior of the bowl but permits it to drop onto the motor rotor or stator from whence it may seek its way between the windings of the motor stator to the outer part thereof, where it may flow through the Vertical passes in the stator laminations as indicated at 89.

The ordinary non-ferrous coil bars are used as clamping bolts for holding the disk laminations of the squirrel cage motor rotor. These bars. must beinclined as illustrated in Fig. 1 and are exposed 'to the magnetic air gap between the rotor and the stator. Thus the peripheral surface of the rotor is provided with a'series of slots. By placing the'leading edge of these slots on the upper side of this vertically disposed rotor the laminations therebetween act as vanes creating a circulation of the gas impelling liquid down through the air gap. Thus any gas impelling liquid that collects on top of the rotor is drawn down through the air gap to the lower part of the reservoir .16 at the bottom of the housing.

10 represents annular cooling fins on. the outer surface of the housing wall ll.

"1| "represents the cap or closure member for the housing 18 which is arranged to carry the upper bearing 12 for the rotor shaft 28. 13 represents the pump outlet which is connected to the gas chamber 49 by means of the passageway 14.

The structure illustrated in Fig. 6 is provided with features that are found in both Figs. land 4. The valve structure 20 is conical in shape and is secured to the shaft 28 and thereby operates with the speed of the motor rotor.

The pump rotor 32 is threadably secured to the sleeve 16 which is rotatably supported from one end by the antifriction bearing 11 resting on the upper surface of the flange 18 which is secured to the shaft 28. Owing to the relative movement between the pump rotor 32 and the flange 18 the surface of the latter is provided with 'the groove '19 whichpicks up the pumping liquid and lubricates the engaging surfaces therebetween together with the bearing 11 and the sleeve Hi.

The upper end of the sleeve 16 is provided with the sun gear 80 which is constantly in mesh with the planet'gears 8| 'secured'by the bolts 82 to the spider 83, the outer flanges 83' of which are arranged to be bolted between the outer flanges of the lower and upper casing members II and 59.

84 represents an internal circle gear arranged to mesh with the planet gears 8| and which is secured to theshaft 28 by means of the key 85. Thus the internal gear 84 rotates at the same speed as the shaft 28 and the planet gears 8| rotate the sun gear 80 and the pump rotor at a higher speed than the shaft 28. Thus by changing the gearing ratio different relative speeds may be obtained between the operation of the valve 20 and the pump rotor 32. This structure differs from that disclosed in Fig. 1 wherein the pump rotor is operated at motor speed and the valve speed was reduced by driving from the sun gear.

88 represents a volute within the wall M of the pump stator or casing. This volute is arranged to produce an equal velocity of the flow of the fluid being pumped before it ispicked up by the rotary screw 48: This structure also has the effect of reducing the velocity of the fiuid and thereby transforming the energy into pressure and thus aid in compressing the gas being pumped.

As the fluid is discharged into the upper portion of the reservoir Hi the gas under compression separates from the impelling liquid and flows up through the'chamber 49 past the gear 8| and into the motor compartment past the winding of the statorand is exhausted out the opening 81 in the top of the lid 88. This circulation of thegas carries a suflicient amount of the impelling fluid to lubricate the rotary elements Within the casing and aids in cooling the motor.

- 'In operation the-pump rotors of these pumps liquid, which in most instances would be oil, such as light mineral oil. As the rotor revolves this liquid is forced through the centrifugal passageways 38 where it is picked up by the inclined screw and discharged at the top thereof. A suction is thereby created in the vortex chamber 31. When the rotary valve opens the gas port 22 the suction acts upon the check valve 6| to admit gas into the vortex chamber from whence it is drawn behind the oil through the centrifugal passages. When the valve 20 closes the gas port 22 'the'generation of the suction continues until the valve 20 opens'the port IE! to admit oil to'the vortex chamber. The slug of oil thus admitted traps thegas ahead of it in the centrifugal and spiral passes compressing the same and a suction is again created behind the slug of oil just admitted to the pump rotor after the valve 20 closes the port l9. The suction developed by the alternate slugs of oil finally exhaust the vortex chamber and the gas passageway 2| and thereby draw the alternate slugs of gas into the vortex chamber.

The "continuously restricted ventrifugal passages which contain alternate slugs of oil and gas together with the centrifugal'force applied to the oil compress the gas slugs before they are permitted to escape to the gas pressure chamber. In the instance of a refrigerating system this chamber is initially charged with the refrigerant gas or liquid, as the case may be, before the system is sealed.

When the motor is stopped after supplying the required operation in circulating the refrigerant the oil will adjust itself within the pump rotor to equalize the pressure conditions regardless of whether the port I9 is open or closed. Since the oil in the reservoir is exposed to the pressure within the gas chamber the pressure becomes equalized within the casing. During operation the flow of the oil into the vortex chamber through the port I9 is aided by the pressure of the gas within the chamber as well as the suction created in the vortex chamber. In view of these conditions the advantage of changing the radial position and the extent of the opening of the port 22, as stated above, for effecting the desired valve operating time for different types of refrigerants is quite apparent.

These pumps are designed primarily to produce a Vacuum for operating in refrigerating systems. Thus the low pressure refrigerants such as carrene (CHzClz) methyl formate and others may advantageously be employed. These pumps may also be advantageously employed to operate the medium and higher pressure refrigerants such as sulphur dioxide (S02), dichloridifluoromethane (CClzFz) known as freon, F-12, kenetic No. 12 which is non-toxic, noncorrosive and non-inflammable and its thermodynamic properties are ideal. Ammonia (NH3) which requires the highest pressure of these refrigerants may also be used.

These vacuum pumps exhaust the evaporator of the refrigerator, thereby reducing the boiling point of the carrene to allow the heat of the box to vaporize the carrene. The vaporization of the carrene absorbs heat from the evaporator and the vacuum developed by the pump carries it in that form to the vortex chamber where it is compressed, which action increases the temperature thereof. The compressed carrene vapor then will be partially filled with the gas impeller" passes to a condenser where it is cooled and thereby liquefied. The liquid is then forced into a receiver by the pressure of the vapor developed by the pump. The carrene liquid within the receiver increases the pressure therein. However the increased pressure is below atmospheric but it is sufiicient to force the carrene through a metering device to the evaporator which is maintained under vacuum by the pump. The circuit just described represents the operating cycle of the refrigerant.

The vacuum pump illustrated in Fig. l is designed to operate at moderate squirrel cage induction motor speeds. The valve rotates at a slower speed than the pump rotor. The pump shown in Fig. 4 is designed to operate at a slower speed than the device of Fig. 1. This motor is larger in diameter and has slower R. P. M. characteristics which permit the operation of the valve at the same speed as the pump rotor. In the pump shown in Fig. 6 the pump rotor is operated at a higher speed than the motor and the valve is operated at motor speed. A pump of this character is better suited to operate refrigerants that require higher initial pressure. Thus by changing the relative speed of the valve and the pump rotor the characteristics of the pump may be suited for different refrigerants.

.Again the structure of the pump rotor comprising this invention is adapted for assembly Within the rotor motor, which greatly simplifies the motivating unit of a refrigerating system.

I claim:

1. In a gas pump, the combination of a rotary impeller provided with a spiral thread of progressively diminishing capacity, a centrifugal pump arranged to deliver gas and liquid to the impeller, and a rotary valve connected to the pump and arranged to deliver alternate slugs of gas and liquid thereto.

2. In a gas pump, the combination of a rotary impeller provided with a spiral thread of progressively diminishing capacity, a centrifugal pump arranged to deliver gas and liquid to the impeller, a valve casing having spaced gas and liquid inlets, and a rotary valve in said casing arranged to deliver alternate slugs of gas and liquid to the pump.

3. In a gas pump, the combination of a rotary impeller provided with a spiral thread of progressively diminishing capacity, a centrifugal pump arranged to deliver gas and liquid to the impeller, a rotary valve connected to the pump and arranged to supply alternate slugs of gas and air thereto, means for supplying gas to said valve, and a return for said liquid from the discharge of said impeller to the valve.

4. In a gas pump, the combination of a rotary impeller provided with a spiral thread of progressively diminishing capacity, a centrifugal pump arranged to deliver gas and liquid to the impeller, a rotary valve connected to the pump and arranged to supply alternate slugs of gas and liquid thereto, means for supplying gas to the valve, and means for returning liquid from the discharge end of the impeller to the valve under discharge pressure.

5. In a gas pump, the combination of a rotary impeller having a spiral screw pump thereon, a centrifugal pump in said impeller arranged to deliver a gas and a liquid to the screw pump, and a rotary valve on said impeller for delivering alternate slugs of a liquid and a gas to said centrifugal pump.

6. In a gas pump, the combination of a rotary impeller having a spiral screw pump thereon, a

centrifugal pump in said impeller arranged to deliver a gas and a liquid to said screw pump, and a rotary valve for delivering alternate slugs of a liquid and a gas to said centrifugal pump, said valve being operated in timed relation with said impeller but at a diiferent relative speed.

-7. In a gas pump, the combination of a pump stator, a rotary impeller arranged to rotate within said stator and having a spiral screw thereon, a centrifugal pump arranged to deliver gas and liquid to said screw, and a rotary valve connected to the centrifugal pump and arranged to deliver alternate slugs of gas and liquid thereto.

8. In a gas pump, the combination of a pump stator, a volute in said stator, a rotary impeller arranged to rotate within said stator and having a spiral screw thereon arranged to receive gas and liquid from said volute, a centrifugal pump arranged to deliver gas and liquid to said volute, and a rotary valve connected. to the centrifugal pump and arranged to deliver alternate slugs of gas and liquid thereto.

9. In a gas pump, the combination of a rotary casing, a screw impeller in the casing forming a continuous spiral conduit, and a centrifugal iin peller in said casing arranged to deliver gas and liquid to said screw impeller, said impellers being structurally united with said casing to form a unitary rotary body.

10. In a gas pump, the combination of a rotary casing, a screw impeller in the casing forming a continuous spiral conduit, a centrifugal impeller in said casing arranged to deliver gas and liquid. to said screw impeller, said impellers being structurally united with said casing to form a unitary rotary body, and a rotary valve connected to the centrifugal impeller to deliver alternate slugs of gas and liquid thereto.

11. In a gas pump, the combination of a motor rotor, a casing within said motor rotor, a screw impeller in said casing forming a continuous spiral conduit, and a centrifugal impeller in said casing arranged to deliver gas and liquid to said screw impeller, and a rotary valve on said casing arranged to admit alternate slugs of gas and liquid to the centrifugal impeller, said casing, impellers and valve being structurally united with said motor rotor.

12. In a gas pump, the combination of a rotary impeller, a spiral thread pump thereon, a centrifugal pump arranged to deliver gas and liquid to the spiral pump, a rotary valve to deliver alternate slugs of gas and liquid to the centrifugal pump, and operative connections between the impeller and the rotary valve to operate the latter.

13. In a gas pump, the combination of a rotary impeller, a spiralthread pump thereon, a centrifugal pump arranged to deliver gas and liquid to the spiral pump, a rotary valve to deliver alternate slugs of gas and liquid to the centrifugal pump, and operative connection between the impeller and the centrifugal pump to operate the latter.

14. In a gas pump, the combination of a rotary impeller, a spiral screw pump thereon, a centrifugal pump in said impeller arranged to deliver a gas and a liquid to the screw pump, a rotary valve driven by said impeller for delivering alternate slugs of a liquid and a gas to said centrifugal pump, and means for equalizing the fluid pressure effective against the opposite ends of said impeller.

15. In a gas pump, the combination of a ing provided with means for the ingress and egress of gas, a rotary impeller mounted in the housing, a spiral screw pump thereon, a centrifugal pump in said impeller and arranged to deliver housa .gas and a liquid to the screw pump, a rotary valve driven by said impeller for delivering a1ternate slugs of a liquid and a gas to the centrifugal pump, a reservoir in the housing to receive the 9 rotary valve driven by said impeller for delivering alternate slugs of a liquid and a gas to the centrifugal pump, a reservoir in the housing to receive the liquid from the screw pump, and means for supplying liquid from said reservoir to the rotary valve under pressure developed by the pumps.

17. In a gas pump, the combination of a housing provided with means for the ingress and egress of gas, a rotary impeller mounted in the housing, a spiral screw pump thereon, a centrifugal pump in said impeller and arranged to deliver a .gas and a liquid to the screw pump, a rotary valve driven by said impeller for delivering alternate slugs of a liquid and a gas to the centrifugal pump, a reservoir in the housing to receive the liquid from the screw pump, and means whereby the pressure developed by the pumps is imposed against the opposite ends of the impeller.

ARTHUR A. ALDRIDGE.

Images