US2882698A

US2882698A - Refrigerating system

Info

Publication number: US2882698A
Application number: US485134A
Authority: US
Inventors: John R Boyle
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-01-31
Filing date: 1955-01-31
Publication date: 1959-04-21
Anticipated expiration: 1976-04-21

Description

April 1959 J. R. BOYLE REFRIGERATING SYSTEM 4 Sheets-Sheet 1 Filed Jan. 31, 1955 INVENTOR. Joizrzji fioyle, 1

BY hm April 21, 1959 J, R. BOYLE REFRIGERATING SYSZFEM 4 Sheets-Sheet 2 Filed Jan. 31, 1955 A ril 21, 1959 J. R. BOYLE 'REFRIGERATING SYSTEM INVENTOR. Jo/zzzEBqgZe,

4 Sheets-Sheet 3 Flled Jan. 31, 1955 April 1959 J. R. BOYLE 2,882,698

REFRIGERATING SYSTEM Filed Jan. 31, 1955 4 Sheets-Sheet 4 United REFRIGERATIN G SYSTEM John R. Boyle, Chicago, Ill.

Application January 31, 1955, Serial No. 485,134

Claims. (Cl. 62-220) The present invention relates to liquid pumping or distributing apparatus, and particularly to an improved rotary type of pumping or distributing apparatus wherein the liquid is acted upon centrifugally within a vertically extending spinner which is revolved at a relatively high speed for lifting or distributing the liquid within the spinner.

One of the particular utilities of this type of pumping or distributing apparatus is the ability to handle liquids that are substantially at the vaporizing or flash point, but without having the pump cause vaporization or flashing of the liquid in the pumping operation. One typical situation is the pumping of liquid refrigerants in refrigerating systems. Another situation is the pumping of volatile liquids such as gasoline, alcohol, etc. Still another situation is the pumping of high temperature feed water to a boiler or the like, where the feed water is substantially at the boiling or flashing temperature. My improved pumping apparatus can be used advantageously in each of these situations for performing a pumping operation without the objectionable vaporizing or flashing which usually occurs at the inlet phase of the ordinary pumping cycle because of pressure reduction.

Referring to the first of these situations, one of the objects of the present invention is to provide an imj proved form of pumping or distributing apparatus which will avoid flashing of the liquid refrigerant in pumping operations performed in refrigeration systems. This is accomplished by an improved construction in which substantially no pressure reduction occurs in the liquid refrigerant on the intake side of the pumping apparatus. It is well known that if a substantial degree of flashing occurs in the pumping or distributing operation the apparatus is not practical. Heretofore, it has been necessary to maintain a gravity head of the liquid refrigerant on the inlet side of the pumping apparatus in avoiding or minimizing flashing, and such arrangements have involved structural complications or have been otherwise objectionable. In my improved apparatus the liquid refrigerant can be lifted from a substantially constant liquid level within a receiver, surge drum or the like, and then pumped or distributed to evaporator coils or the like, all without flashing. Such lifting of the liquid refrigerant from the supply level of the refrigerant to the pumping or distribution level is accomplished centrifugally so that no pressure reduction occurs in this lifting of the refrigerant.

One typical utility of my invention is illustrated in flooded evaporator systems for supplying the liquid refrigerant to the flooded evaporators. These flooded evaporators can be operated more efiiciently if the refrigerant can be circulated therethrough in a plurality of short parallel paths, rather than in one long series path; as, for example, through a plurality of short parallel coils or tubes, rather than through one long series coil or tube. One of the more specific objects of the invention is to provide improved apparatus for performing this type of operation more efliciently.

2,882,698 Patented Apr. 21, 1959 Another typical utility of my invention arises in ex-' pansion valve systems where, under certain operating conditions, overfeeding through the expansion valve causes slugs of liquid refrigerant to pass into the evaporator, and which liquid refrigerant must be separated out so that they will not pass to the compressor. One of the objects of the present invention is to provide improved apparatus for pumping this liquid refrigerant back to the high pressure side of the expansion valve.

Another object of the invention is to provide improved apparatus for separating entrained oil from the liquid refrigerant by a unique centrifugal separating operation.-

Another object of the invention is to provide an improved volatile liquid pump for pumping volatile liq-, uids, such as gasoline, alcohol, etc.

Another object of the invention is to provide an improved feed water pump for pumping feed Water to boilers substantially at the vaporizing point without flashing.

Other objects, features and advantages of the invention will appear from the following detailed description of certain preferred embodiments thereof. In the accompanying drawings illustrating such embodiments:

Figure 1 is a schematic diagram wherein my improved pumping or distributing apparatus pumps the liquid refrigerant to the coils of a flooded evaporator system;

Figure 2 is a vertical sectional view through one em-v bodiment of my improved pumping apparatus;

Figure 3 is a horizontal sectional view taken approximately on the plane of the line 33 of Figure 2;

Figure 4 is a horizontal sectional view taken approximately on the plane of the line 44 of Figure 2, showing the apparatus for effecting oil separation from the liquid refrigerant;

Figure 5 is a horizontal sectional view through the low er end of a modified form of spinner;

Figure 6 is a schematic diagram of an expansion valve system showing one typical arrangement wherein my improved refrigerant pump receives separated liquid refrigerant from the low side of the evaporator and returns it into the high pressure line leading to the expansion valve;

Figure 7 illustrates a modified construction in which the liquid refrigerant is distributed at different levels;

Figure 8 is a vertical sectional view of a further embodiment of my improved pump, this figure corresponding to a section taken on the line 8-8 of Figure 9;

Figure 9 is a horizontal sectional view through the pump housing, taken on the plane of the line 9-9 of Figure 8;

Figure 10 is a vertical sectional view of another embodiment of my improved pump;

Figure 11 is a horizontal sectional view through the pump housing, taken on the plane of the line 11-11 of Figure 10;

Figure 12 is a horizontal sectional view on an enlarged scale, taken on the plane of the line 1212 of Figure 10;

Figure 13 is a fragmentary vertical sectional view of another form of liquid lifting tube;

Figure 14 is a similar view showing a modified form of stationary admission means;

Figure 15 is a horizontal sectional view taken on the plane of the line 1515 of Figure 14;

Figure 16 is a fragmentary vertical sectional view of another embodiment of stationary admission means;

Figure 17 is a horizontal sectional view taken on the plane of the line 1717 of Figure 16;

Figure 18 is a vertical sectional view of still another embodiment of liquid lifting tube, and

Figure 19 is a vertical sectional view of an embodiment which combines the spinner tube having the separating jets of Figure 2 with the pump impeller arrangement of Figure 8.

Referring first to the refrigerating system diagramman-earl shown in Figure 1, this comprises any suitable compressor .11 discharging into a condenser 12, which t! turn discharges the condensed refrigerant into a receiver 13. The liquid refrigerant accumulating in this receiver Bisconducted through line 14- to a low pressure receiver 15 provided with a float controlled inlet valve 16 for maintaining the liquid refrigerant in the receiver 15 at a substantially constant level, indicated at 17'. A suction line 19 leading from the upper portion of the receiver 15 conducts the vapor back to the inlet port of the com pressor 11. The evaporator 20 is of the flooded type, having a plurality of short parallel coils, represented by the three flooded

coils

21, 22 and23. Each of these evaporator coils connects to a common .return line 24 leading back to the upper .partof .the low pressure receiver 1 5.

My improved refrigerant pump ordistributor is desi nated '25 in its entirety, and extends upwardly from the low pressure receiver 15 for :'drawing refrigerant therefrom I-andpumping it to :the

coils

21, 22 and 23. :For clarity "of illustration, the pump 251is illustrated in ;Fig ure 1 in considerably larger scale than the other apparatus. The pump comprises an upwardly extending ey lindrical housing 27 having a supporting flangelit which is bolted to a mounting flange 29 surrounding an opening 31 in the top of the low pressure receiver or surge drum 15. Revolving axially within the housing .27 is a cylindrical tubular spinner 35 which serves to lift the liquid refrigerant centrifugallyfrom the receiver to the pumping or distributing elements revolving with the spinner 35. The spinner is adapted to be driven by an electric motor 36 mounted vertically above the upper end of the spinner and connected thereto through a drive shaft 37. Bearing support for the upper endof the spinner'35 is established by the motorbearings or by a hearing for the short drive shaft 37, and bearing support for v the lower portion of the spinner is established by a bearing sleeve 39 mounted on the outer side of the. spinner and rotating within a bearing spider 411 secured. to the cylindrical housing 27.

Mounted on the upper end of the rotary spinnerfifi is an impeller or runner 45, which is shown as having a series of discharging jets 45 preferably of elliptical cross section, as shown in Figure 2. However, this impeller-may be of any preferred type or any conventional typelsiniilar to that used in a centrifugal pump. This impeller revolves within a centrifugal pump housing 46 from which radiate a plurality of discharge ports, exemplified by

the'three ports

47, 48 and 49. As shown in Figure 3, the upper end of the rotary spinner 35 opens into the central area 51 of the impeller for feeding the refrigerant directly to the impeller jets 45'. The plurality ofangularlyspaced discharge

ports

47, 43, and 49 are connected to distribute the liquid refrigerant to the plurality of flooded evaporator coils 21, 22 and '23, which may be'connected to have a top feed or a bottom feed, as desired. For example, the coil 22 is shownas having a bottom feed, Where the refrigerant is fed to the bottom end of the coil for anwascending flow; upwardlytherethrough. The pressure discharge of the refrigerant from the centrifugal runner 45 makes the bottom feed of the coils practicable. The pump housing 46 may have its upper portion closed with a packing-seal around the shaft'37, or the housing may be extended to establish a hermetically sealed motor 36 enclosed in a shell 54.

The lower end of the tubular spinner is preferably constricted by a constricting and liquid supporting ring 55 having a reduced inlet diameter D. Liquid spinning freely inside a rotating verticalcylinder which is restricted or confined at the bottom end will form aparabola ofequalization extending upwardly along the inner wall of--.the cylinder. For a given speed of rotation, the height that this parabolic liquid annulus, indicated at 56, will climb in the cylinder will depend upon the-ratio 1 sequent-starting operations.

of the diameter D of the opening in the ring 55 to the inside diameter T) of the cylinder 35, ie the radial proportionality existing between the inlet diameter D and the centrifuging diameter D. The greater the diiference between these two diameters the higher will the liquid climb in arriving at the parabola of equalization. The ring 55 may be regarded as supporting the centrifugal liquid annulus 56. In some situations it may be desired to prevent or minimize vortex spinning of the liquid surrounding the lower end of the rotary spinner, and this may be accomplished by providing stationary anti-vortex blades 57 extending inwardly from the lower end of the housing 27 just below the bottom of the rotating spinner.

The lower end of the tubular spinner is normally submerged a substantial distance below the liquid level 17 in the receiver 15, but the device is operative with only a relatively shallow submergence. The liquid refrigerant entering the lower end of the spinnerpieks up the rotary motion thereof and immediately has a centrifugal force developed in the liquid for causing itto move vertically up along the inner surface of the spinner. Aspreviously stated, the liquid moves upwardly in the form of a centrifugal annulus, indicated in dotted lines at 56, assuming a parabolic curvature at progressively higher points along the inner wall of the spinner. The centrifugal forces inherent in this centrifugal annulus of liquid 56 tend to press the liquid outwardly against the inner wall of the spinner, so that there is no pressure reduction in the liquid at any point from the time that the liquid picks up the rotary motion of the spinner until it has reached the top of the spinner and been discharged centrifugally into the impeller blades. There being no pressure reduc tion at any point in this pumping operation,'it follows that there will be no flashing of the liquid refrigerant.

In Figure 5 I have illustrated a modified arrangement at the lower end of the rotary spinner 35. The ring 55 is provided with liquid lifting vanes 58 extending inwardly into the restricted opening D, these vanes, having a helical skew or pitch for augmenting the lift of the liquid through the restricted opening D. Ineach of the embodiments illustrated in Figures 2 and 5, the lower end of the spinner need only be submerged a ,very short distance below the liquid level ,17. Typical operating speeds of the spinner range from approximately 1100 r.p.rn.- to 1750, r.p.rn., depending upon spinner diameters,,.height of lift, etc. Typicalspinner diameters (inside diameter D) of devices which I have successfully operated have ranged from -5 inches to 8 inches. or larger, and in these devices operated at. speedsoffrom 1150 rpm. to l7.50 r.p.m. Ihaveobtained heightsof liquid lift. extending up to 4 or-S feet or more,.- depending upon ;the D,to D ratios, etc. The devicewill function satisfactorily with, a depth ofsubmergence below the liquid level 17 of only. a fraction of aninch.

Where the spinning cylinder opens into aclosed top impeller chamber pump housing or the like, itmay be advisable to, vent the -upperend of. the assembly ,to avoid the entrapment of alarge gas or air bubble there in, which may impair: the normally inherent self-priming characteristic. The presence of this bubble may ,make the preliminary starting operation diflicult, butsubstantially no difficulty is ,encounteredon immediately sub- Such a .vent for dissipating the bubble may consist of a vent duct or pipe .59 opening into the ,motor space, where themotor is, not hermetically sealed, or opening outwardly. of the motor and'housing where the motor is hermeticallysealed.

Another featurewhich I may embody in myirnproved refrigerant-pumping apparatus is thefeature. of. separating entrained oil from the refrigerant by a centrifugal separating principle. This is effected by providing the spinner with one or more oil separating jets 61, which extend radiallyfrom the spinner cylinder and have thflilgillflfilgfildS diSEOSdi at a,radius, which is substantially equal to the depth of the annulus 56 of liquid refrigerant at that height in the spinner. The oil, being of lighter density than the refrigerant, will be centrifugally separated therefrom and will form a film or thin layer on the inner surface of the refrigerant annulus 56 at the level of the intake ends of the separating jets 61. Hence, this oil will be discharged centrifugally out through the jets 61. The outer ends of the jets discharge into an oil collecting pocket which is shown in the form of an annular chamber 62 formed in the wall of the cylindrical housing 27. The oil collecting in this annular chamber can be returned to the compressor 11 if desired, but in the illustrated arrangement I have shown the annular chamber 62 discharging the separated oil through pipe 63 into a trap 64 having free drainage or discharge, either to the compressor suction line 19 or to an oil reservoir. Thus, a continuous oil separation occurs throughout the entire time that the refrigerant pump is operating.

Referring now to the modified system shown in Figure 6, in this system the receiver 13 supplies liquid refrigerant through the pressure line 67 to an expansion valve 68 which discharges into any suitable form of evaporator 69. This evaporator in turn discharges into the upper portion of a surge drum 71 from which a suction line 72 extends back to the compressor. In this type of installation the expansion valve 68 may have a tendency to overfeed under certain operating conditions, with the result that slugs of liquid refrigerant are passed into and through the evaporator 69. The purpose of the surge drum 71 is to catch these slugs of liquid refrigerant and prevent their passing to the compressor 11, but the reintroduction of this liquid refrigerant back to the liquid side of the expansion valve 68 usually introduces pumping problems because of relatively high pressure differentials, flashing, etc. My improved non-flashing centrifugal pump 25 affords a satisfactory solution to these problems, and is preferably connected into the system as shown in Figure 6. Here again, for clarity of illustration, I have shown the pump 25 in considerably larger scale than the remainder of the apparatus. Leading from the bottom of the surge drum 71 is a liquid discharge pipe 76 which discharges accumulated liquid refrigerant into a sump or constant level chamber 77. The non-flashing centrifugal pump is indicated at 25, and has the previously described tubular spinner 35 for lifting the refrigerant from the chamber 77 to the pump impeller without flashing. In this embodiment, it is necessary that the pump have a relatively high discharge pressure, adequate to pump its liquid refrigerant into the high pressure liquid line 67 extending from the receiver 13 to the expansion valve 68. This relatively high pressure, which may run as high as 150 or 200 pounds, is obtained by a relatively high speed at the periphery of the impeller 45, resulting from a large impeller diameter, or a high driving speed, or both. In this type of installation the centrifugal pump housing 46 need have only one outlet port, which connects through conduit 78 with the high pressure side of the expansion valve 68. Interposed in conduit or pipe 78 is a valve 79 which may either have a conventional check valve or an electrically opened valve energized over circuit connections 79 concurrently with the motor of the centrifugal pump 25, this valve preventing the refrigerant in high pressure line 67 from backing up into the centrifugal pump when the latter is not operating. The pumping operation is preferably made automatic by providing a float responsive switch 80 in the surge drum 71, which starts the pump motor 36 when a substantial amount of liquid refrigerant has accumulated in the surge drum, and cuts off the pump motor when this accumulation has been pumped back into the high side of the system. This embodiment may also include the oil separating feature for separating oil from the liquid refriger- 6? ant and discharging it back to the compressor 11 through oi'l return pipe 63.

In Figure 7 I have illustrated another modified embodiment in which the liquid refrigerant is distributed at different levels for distribution to different evaporators or different evaporator coils. In this embodiment the spinner 35a lifts an annulus 56 of liquid refrigerant from the liquid level chamber, as before described, but projects this liquid at a plurality of different levels by vertically spaced sets of

jets

81, 82, 83, etc. projecting radially from the spinner. The spinner may also be arranged to discharge liquid refrigerant over the top edge of the cylinder. At each level of discharge, circular troughs 87 are fixedly mounted in the stationary outer housing 27 and these discharge selectively through separate conduits 88 to different evaporators or different evaporator coils. The latter preferably have connection with a common liquid return for returning the unvaporized refrigerant to the liquid level chamber 89. The jets, 81, 82, 83, etc. may have calibrated apertures therein proportioned for securing any desired proportions of flow to the different evaporator coils. However, such calibrated apertures may plug up from dirt, and accordingly in situations where flow proportioning is desired, I prefer to attain it by varying the degree of intrusion of the jets into the spinner cylinder, i.e. proportioning the distance that each ring of jets projects inwardly into the liquid annulus 58 so as to have different pressure heads of the liquid annulus eifec-- tive on the inlet port ends of the jets. In the illustrated arrangement, these inlet ends follow the parabolic curvature of the liquid annulus for obtaining a substantially uniform degree of immersion in the liquid annulus and asubstantially uniform discharge from all of the jets.

My improved centrifugal pump is also adapted to numerous other uses. Because of its non-flashing characteristic it functions admirably for the pumping of practically all volatile liquids, such as gasoline, alcohol, hot water, etc. Also, because of its non-flashing characteristic it can be advantageously employed as a feed water pump for pumping high temperature boiler feed water into a boiler. In such situations the feed water may be almost at a flashing temperature, and the non-flashing characteristic of the pump enables it to handle this high temperature feed water without flashing. My improved pump is also self-priming so that it can be started and stopped automatically or manually without requiring any priming attention. Furthermore, it cannot be injured by freezing where it is pumping water or is otherwise employed in a situation susceptible to freezing. For example, my improved pump can be employed very advantageously for projecting Water in outdoor spray pond installations which are extensively used for cooling condenser water, etc.

In Figures 8 and 9, I have illustrated a further embodiment of my volatile fluid pump. The spinner or liquid lifting tube 35b is attached concentrically to a horizontally disposed pump impeller 95, being attached directly to the inlet port or eye 96 of the impeller. This impeller is of conventional form, comprising impelling vanes 98 which act centrifugally on the liquid for discharging it from the volute-shaped housing 100 through discharge outlet 102. The lifting tube 35b and impeller are driven by a vertically disposed electric motor 104 which is mounted on the top of the pump housing and which has its rotor shaft 106 secured to the impeller 95. If desired, the motor 104 may be enclosed within a separate housing 108 secured to the upper side of the pump housing 100. The rotor shaft 106 enters the pump housing 100 through a sealed bearing 109 in the top wall of the pump housing.

Extending down from the bottom side of the pump housing 100 is a sealing neck 110 which closely encircles the spinner or lifting tube 35b. A flange 112 on the lower end of this sealing neck 110 is secured by bolts or screws 7 114 to the top wall of a tank or liquid receiver 116 which] sesame 6 houses the lifting tube 355. A liquid. seal, preferably in' the form start ring'117fis interposed between the sealing neck 110 and the lifting tube 3515, this 0 ring sealing the pump housing 100 from the tank or receiver 116, and also affording some measure of lateral bearing support for the lifting tube 351;. When a relatively short lifting tube is employed, such as shown in Figure 8, no lower bearing is required for the tube. The lower end of the tube is constricted by the liquid supporting ring 55b. A vortex eliminator 118 is stationarily secured to a bottom wall of the tank 116, this eliminator preferably comprising a plurality of vanes radiating outwardly from the center line of the inlet ring 55b, as hereinafter shown in connection with Figures 12 to 18. The liquid which is tobe pumped enters the tank 116 through inlet 120, and is sucked up by the lifting tube 35b as a parabolic annulus'of liquid 56. It thus enterstherunner of the pumpwithout reduction of pressure of the liquid, from the time that it enters through inlet 120 until it has been discharged centrifugally by the impeller blades 98.

In Figures to 12 I have shown still another embodiment of my improved pump. In this embodiment, the centrifugal pump and the liquid lifting tube 350 are housed in the same housing 122. A partition or diaphragm wall 123 is welded at its edges to the vertical wall of the housing 122, and divides this housing into an upper pump compartment 124 and a lower tank or receiver 125. The lifting tube c passes down through an opening 126 in this partition wall 123, which o ening is provided with a downwardly extending flange 127 in which is confined an O ring 128 having bearing engagement against the lifting tube 350. The upper end of the lifting tube opens into the center of the pump runner 130, which has centrifugal vanes 131 for discharging the liquid out throu h the outlet port 132. The top of the pump compartment 124 is closed by a cover plate 134, which is secured by bolts 135 to an outwardly pro ecting flange 136 provided at the upper edge of the housing 122. The interior of the pump compartment 124 is given a volute configuration by a light sheet metal wall 137 which has its unoer edge welded to the under side of the cover plate 134 in the desired spiral curvature. Bolts 138 pass through the diaphragm wall 123 and through the cover plate 134 at spaced points outside the curvature of the volute wall 137. The diaphra m wall 123 and the cover plate 134 have sufiicient resilience so that tightening of the bolts 138 forces the lower ed e of the volute wall 137 into rigid binding engagement with the dia hragm wall 123. The shaft 139 of electric motor 140 passes through a rotary shal 141 in cover plate 134 and has its lower end secured to the pump runner 130. If it is desired that the motor 140 be enclosed, this can be provided for by employing a motor housing 144 which extends upwardly from the cover plate 134, and which is in turn provided with a removable cover plate 145 of its own.

The inlet construction at the lower end of the lifting tube 35c is in the form of a conical lip 55c. This lip is shown as being formed with deflecting scoops 148 which are punched out of the lower edge of the lip and face in the direction of rotation of the lifting tube. These scoops forcibly deflect the adjacent liquid inwardly into the interior of the conical lip 550, where the liquid takes up the rotation of the lifting tube and rises in the tube under centrifugal force to the pump runner 130. A vortex eliminator is secured to the bottom wall 122' of the housing 122 in close proximity to the inlet end of the lifting tube 35c, this vortex eliminator compris ing

vanes

151 and 152 secured at right angles to each other and intersecting substantially at the center line of the lifting tube.

In Figure 13, I have shown a modified lifting tube 35dhaving a conical lip 55d, but without having the deflecting scoops 148 formed therein. This conical end ss'fq'ui s down below what wg orm ll be the b9?- tempt the vortex in the liquid, as indicated by the dotted lines.

Figures 14 and 15 illustrate a modified form of inlet admission means for the inlet end of the lifting tube 35a. The lower end of the tube is formed with a restricting lip 55c, and extending upwardly into the annular opening defined by this lip is a stationary open ended tube or cup 155. The lower end of this stationary inner tube or cup 155 is spaced from the bottom wall 122' of the liquid container, and is fixedly secured to this bottom wall by outwardly radiating spider arms 156 having attaching ears 157 which are riveted or welded to the bottom wall 122'. A substantial part of the liquid entering the lifting tube 35e flows along the bottom wall of theconta iuer and moves upwardly into the lifting tube through the open ended admission tube 155. This arrangement of stationary admission tube and supporting spider arms minimizes vortex action at the lower end of the lifting tube 35a.

Figures 16 and 17 illustrate another embodiment of admission control means for the inlet end of the lifting tube 351. The lower end of this lifting tube is provided with an inwardly extending constricting lip 55f, and extending upwardly into the central opening defined by this lip are a plurality of fixed curved vanes 161. The ver tically extending curved portions of these vanes are formed at their lower end with horizontally extending curved arm portions 161' which have stationary attachment below the lower end of the lifting tube 35 It will be seen from Figure 17, that each vane 161 and its supporting arm portion 161' is curved in a direction counter to the direction of rotation of the lifting tube 35], so as to function as a stationary scoop for deflecting the surrounding mass of rotating liquid inwardly and upwardly into the constricted lower end of the lifting tube 35]. The horizontal arm portions 161 of these vanes may be secured to the bottom wall 122' of the liquid container; or they may be welded or otherwise secured in the lower end of a stationary outer tube 27 which extends down below the lower end of the lifting tube, comparable to the arrangement illustrated in Figure 2.

Figure 18 illustrates another embodiment of lifting tube 35g having inwardly extending constricting lip 55g. Within the opening defined by this lip are arranged a plurality of propeller-like vanes 165 which are pitched or deflected in a direction to induce an upward flow of liquid into the lifting tube 35g. An arrangement of vortex

eliminatin g vanes

151, 152 is preferably arranged on the bottom wall 122 in relatively close proximity to the'propeller vanes 16 5.

Figure 19 illustrates an embodiment which takes the spinner tube 35 of Figure 2 with its separating jets 61, and combines this spinner tube with the pump impeller 95 of Figures 8 and 9 having the curved impeller vanes 98 discharging through the tangential discharge outlet 102. This embodiment can be used advantageously to effect the non-flashing pumping of liquids having entrained oil or other lighter liquids which it is desired to separate out from the liquid being pumped.

While I have illustrated and described what I regard to be the preferred embodiments of the present invention, nevertheless it will be understood that such are merely exemplary and that numerous modifications and rearrangements may be made therein without departing from the scope of the invention.

I claim:

1. In a refrigerating system comprising a compressor, condenser and evaporator, the combination therewith of a liquid level chamber for receiving the liquified refrigerant from the condenser, a centrifugal pump for pumping the refrigerant to said evaporator, and a revolving tubular spinner lifting the liquiiied refrigerant centrifue lr om Said ui el chamber and sup n it t a rav tate? 12am?- 2. In a refrigerating system of the class described comprising a compressor, condenser and evaporator, the combination therewith of a liquid level chamber for receiving the liquified refrigerant from said condenser, a revolving tubular spinner lifting the liquid refrigerant centrifugally from said liquid level chamber, a centrifugal impeller mounted on said tubular spinner and receiving the refrigerant which is centrifugally lifted in this spinner, said impeller projecting said refrigerant centrifugally under pressure, a housing surrounding said impeller, and means for conducting the refrigerant from said housing to said evaporator.

3. In a refrigerating system comprising a compressor and condenser for compressing and condensing a refrigerant and an evaporator for evaporating the same, the combination therewith of a liquid level chamber for receiving the liquified refrigerant from the condenser, 21 substantially vertical tubular spinner mounted for axial rotation with its lower end immersed in the liquid in said chamber, said spinner being operative to lift the refrigerant from said chamber in the form of a centrifugal liquid annulus rising within said spinner, and to discharge said liquid centrifugally from said spinner, means for conducting the refrigerant therefrom to said evaporator, and oil separating means operative to centrifugally separate oil from the refrigerant while it is rising within said spinner.

4. In a system of the class described, the combination of a liquid level chamber holding liquid refrigerant at a substantially constant level therein, a revolving tubular spinner lifting the liquified refrigerant from said chamber in the form of a centrifugal liquid annulus rising within said spinner, jet means carried by said spinner having its inner end opening substantially at the level of the inner surface of said refrigerant annulus whereby to discharge from this surface any oil which has been separated centrifugally from the refrigerant, and means cooperating with said jet means for conducting the separated oil away from the outer surface of said tubular spinner.

5. In a refrigerating system comprising a compressor, condenser and evaporator, the combination therewith of a surge drum connected between the outlet of said evaporator and said compressor for intercepting liquid refrigerant carried over from said evaporator, and a refrigerant pump arranged for pumping such intercepted liquid refrigerant back to the pressure side of the evaporator, said pump comprising a centrifugal impeller, and a rotary spinner for feeding the intercepted liquid to said impeller without flashing.

6. In a refrigerating system comprising a compressor and condenser for compressing and condensing a refrigerant, and an expansion valve and evaporator for expanding and evaporating said refrigerant, the combination therewith of a surge drum connected between the outlet of said evaporator and said compressor for intercepting liquid refrigerant carried over from said evaporator, a substantially constant level chamber receiving said liquid refrigerant from said surge drum, constant level control means controlling the flow from said surge drum to said chamber for maintaining a substantially constant level of liquid refrigerant in the latter, and a refrigerant pump connected for pumping liquid refrigerant from said constant level chamber back to the inlet side of said expansion valve, said pump comprising a centrifugal impeller, and a rotary spinner arranged to lift liquid refrigerant from said constant level chamber and feed it to said centrifugal impeller.

7. In a refrigerating system comprising a compressor and condenser for compressing and condensing a refrigerant, and an expansion valve and evaporator for expanding and evaporating said refrigerant, the combination therewith of a surge drum connected between the outlet of said evaporator and said compressor for intercepting liquid refrigerant carried over from said evaporator, a substantially constant level chamber receiving said liquid refrigerant from said surge drum, constant level control means controlling the flow from said surge drum to said chamber for maintaining a substantially constant level of liquid refrigerant in the latter, and a refrigerant pump connected for pumping the liquid refrigerant from said constant level chamber back to the inlet side of said expansion valve, said refrigerant pump comprising an electric motor, a centrifugal impeller driven thereby and a rotary spinner revolving with said impeller, said rotary spinner having its lower end submerged in the liquid refrigerant in said constant level chamber and serving to lift the refrigerant centrifugally to said impeller, said impeller being connected to discharge the liquid refrigerant under pressure back to the inlet side of said expansion valve, and a flow control switch responsive to the refrigerant level in said surge drum for controlling the operation of said electric motor.

8. In a refrigerating system comprising a compressor, condenser and evaporator, the combination therewith of a liquid chamber for receiving liquified refrigerant, a revolving tubular spinner lifting the liquified refrigerant centrifugally from said liquid chamber, a centrifugal impeller mounted on said tubular spinner and receiving the refrigerant which is centrifugally lifted in this spinner, said impeller projecting said refrigerant centrifugally under pressure, a housing surrounding said impeller, means for conducting the refrigerant from said housing to said evaporator, oil separating means operative to centrifugally separate oil from the refrigerant while it is rising within said spinner, and means for conducting the separated oil to said compressor.

9. In a refrigerating system comprising a compressor, condenser and evaporator, the combination therewith of a liquid chamber for receiving liquified refrigerant, a revolving tubular spinner lifting the liquified refrigerant centrifugally from said liquid chamber, a centrifugal impeller mounted on said tubular spinner and receiving the refrigerant which is centrifugally lifted in this spinner, said impeller projecting said refrigerant centrifugally under pressure, a housing surrounding said impeller, and means for conducting the refrigerant from said housing to said evaporator.

10. In a refrigerating system comprising a compressor, condenser and evaporator, the combination therewith of a liquid refrigerant chamber, means connecting the outlet end of said evaporator with said liquid refrigerant chamber, a revolving tubular spinner lifting the liquified refrigerant centrifugally from said chamber, a centrifugal impeller mounted on said tubular spinner and receiving the refrigerant which is centrifugally lifted in said spinner, said impeller projecting said refrigerant centrifugally under pressure, a housing surrounding said impeller, and means for conducting the refrigerant from said housing to the inlet end of said evaporator.

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