US2290137A - Compressor for refrigerating apparatus - Google Patents

Description

J y 1942- A. A. ALDRIDGE 2,290,137

COMPRESSOR FOR REFRIGERATING APPARATUS Filed 001;. 22, 1938 4 Sheets-Sheet l ATTORNEY.

"July 14, 1942 A. A. ALD RIDGE COMPRESSOR FOR REFRIGERATING APPARATUS Filed Oct. 22, 1958 4 Sheets-Shea J y MALDRIDGE 2,290,137

COMPRESSOR FOR REFRIGERATING APPARATUS Filed Oct. 22, 1938 4 Sheet-She'gf s 4 i i 1 I 4Q A i 45 [I] INVENTOR.

(A1 ATTORNEY.

Patented July. 14, 1942 UNIT-ED I STATE nnrmcnnarmc rps Arthur a. Aldridge, Pittsburgh, Pa., assignor of one-third to my G. Dorrance and one-third to Robert D. Quinn, both of Pittsburgh, Pa.

Application October 22; 1938, Serial No. 236,565

13 Claims. This invention relates to refrigerating apparatus and particularly to electrically driven re-' frigerating machines for compressing a refrigerant in its vaporized form, and the method of operating the same.

This invention may be advantageously em-- ployed for use with commercial and domestic refrigerating units. v

The principal object of this invention is the provision of a positive displacement rotary screw type pump circulating a metered amount of liquid for compressing a refrigerant in its vaporized form.

Another object is the provision of a body of liquid for trapping a compressed refrigerant in its vaporized form after it has been discharged from a compressor.

Another object is the provision of a refrigerant compressor of the rotary screw type, the coacting surfaces of which conveya circulating liquid with a refrigerant for compressing the latter by accumulation. v

Anotherobject is the provision of a compressor, of the rotary screw type having coacting surfaces which compress a vaporized refrigerant while being conveyed therethrough in the form of a mixture with a circulating liquid.

Another object is the provision of a positive Fig. 2 is a vertical section taken on the line 2-2 of Fig. l.

Fig. 3 is a vertical section of a refrigerant compressor unit built into the rotor of the driving motor.

. Fig. A is a vertical section of 'a refrigerant .7 compressor unit similar to that shown in Fig. 3.

Referring to Figs. 1 and 2 of the drawings, i0 represents the main housing of the refrigerant compressor, the upper portion of which forms the sump for the liquid reservoir The floor of the reservoir is provided-with the port |2 which displacement screw type refrigerant compressor which circulates aliquid as it conveys the refrigerant to induce a suction and maintain a seal therein.

Another object is the provision of a rotary pump structure which eliminates the use of an external drive shaft with bearings and a seal for the same.

Anotherobiect is the provision of a longitudinally disposed tubular member having helical threads therein which coact with a helical thread on a core member disposed therein to produce progressively traveling pockets from oneend of the tubular member to the other uponrelative rotary movement of .the members and wherein the-axis of the non-rotatable member moves in an orbital path.

Other objects and advantages appear in the following description and are particularly pointed out in the claims. V V

The drawings show practical embodiments illustrating the principles of this invention wherein:

Fig. 1 is a vertical section of a 4 refrigerant compressor unit showing the compressor, the reservoir and the rotary valve as three independent elements. 4

opens into the valve chamber l3. The valve chamber I3 is cylindrical and arranged to receive the horizontally disposed rotary valve Hi. The valve I4 is hollow and is open at the inner end thereof to the compressor intake passageway i5 formed in the housing.

|6 represents the refrigerant inlet port for connecting the valve chamber l3 with the refrigerant accumulating chamber H which in turn is connected by the pipe line I8 to the refrigerating system.

An opening or valve port 19 is formed in the wall of the rotary valve M for connecting the ports i6 and i2 successively with the interior of the valve as the latter rotates. These ports are arranged so that the opening l9 cannot connect them simultaneously with the compressor intake passageway i5. with this valvular arrangement alternate portions of liquid and gaseous refrigerant are supplied to the compressor intake passageway I5. I

One end of the rotary valve is closed and is provided with an axially disposed stub shaft 20,

the outer end of which is journaled in the plate 2| bolted to the housing. The intermediate portion of the shaft 20 has the gear 22 secured thereto which meshes with the pinion 23 on the compressor drive shaft 24 journaled in, the housing below the rotary valve. This shaft is supported by the spaced bearings 25 formedintegral with the housing and the end' thrust is .assumed by the antifrictional bearing 26 assembled between the shoulder 21 on the shaft and the gear enclosing plate 2|. The drive shaft 24 extends out through the plate 2| and the stuffing box 28 where it may be connected to any suitable prime mover., r I

A chamber 29 is hollowed out in the housing between the bearings 25 for receiving oil to lubricate these bearings. vThis chamber is connected through the port 30 to the gear chamber. If oil is employed as the suction inducing medium of the compressor and is stored in the reservoir H the passageway 3| may be provided for connecting the reservoir with these chambers, thereby employing oil under pressure for lubrication of the rotary parts.

The compressor 32 is a simple positive displacement pump of the valveless axial feed screw type having a stator and a rotor in telescopic relation and provided with coacting helical threads and of the character disclosed in Letters Patent No. 1,892,217 and 2,028,407 to Moineau.

, As shown in Fig. 1 the compressor is mounted within the cylindrical casing 33and is made up of two parts, the shell stator 34 and the core or worm rotor 35. The bore of the shell is provided with a plurality of helical threads and the perimetral surface of the core is formed with one helical thread less than its corresponding shell. As shown there are two threads formed in the shell and the core is formed with only one. When these parts are assembled the helical surface of the core contacts the double helical thread in the shell forming a series enclosures or pockets each of which are defined by the double pitch of the threads in the shell and are.dis-

posed longitudinally in the shell. When the core is rotated the contact between these surfaces progresses along the threads carrying the pockets in a helical path along the trough of the threads in the shell from one end to the other. If the direction of rotation of the core is reversed these pockets are progressively carried in the opposite direction.

The surface of the core has a rolling contact with the threads in the shell and the axis thereof travels in a circular orbit as it rotates. Thus the extension 36 of the shaft 24 is ofiset to provide for the eccentric movement of the core 85.

Since the positive displacement is created by a continuous rolling contact between the shell and the core there is no driving energy transmitted between them and in this respect they differ from the gear type puinp and since they have a sealed contact throughout their length and do not form a continuous throat they differ from the ordinary screw type pump. It will be noted that it is unnecessary to provide any sealing means at the ends of the elements owing to the fact that the medium pumped is carried longitudinally thereof and not transversely as in the case of gear type pumps.

The discharge is conveyed to the reservoir ll through the pipe 31. If it is desired to employ the. liquid medium within the reservoir II as a trap for checking the flow of the refrigerant back through the pump it is only necessary to maintain the liquid level above the opening of the discharge pipe 31 when the pump is stationary.

The reservoir is enclosed by the dome 38 which is provided with the passageway 39 for conducting the refrigerant, in its vaporized'form and under pressure, to the refrigerating system. A spiral coil 40 may besecured to the passageway for conducting the refrigerant from the dome of the reservoir. This coil aids in condensing the liquid pumping medium from the refrigerant as it passes out of the dome.

. If the worm core of the compressor is continuously operated it is equivalent to a piston of infinite length and produces a constant discharge. But the action of the valve [4 produces a pulsating discharge by feeding a metered amount of the liquid.from the reservoir down into the intake [5 and through the compressor, thereby producing a relatively high suction in 'frigerant into the intake.

the intake by the time the opening IQ of the valve reaches the refrigerant port Hi. This suction is relieved by drawing the vaporized re- Just after the port It is closed the port I2 is opened and more liquid under pressure is metered through the valve and is drawn into the intake passageway I 5 after the refrigerant and is carried through the compressoryproducing an active suction for sucking in the next load of refrigerant. The refrigerant being discharged into the liquid in the reservoir bubbles to the surface and becomes compressed. The pressure of the refrigerant above the surface of the liquid forces it through the port l2 when the valve opening I9 is opposite thereto and the proper amount of liquid admitted may be determined by the size of the port l2.

The circulation of these alternate metered portions of liquid through the compressor induces a relatively high vacuum, thus permitting the use of a refrigerant which reaches atmospheric or subatmospheric pressure such as carrene and methyl formate.

It should be noted that the elements making up this refrigerating apparatus are mounted on the same housing but are independent from one another and when oil is employed as the circulated liquid and the lubricant for the moving parts its leakage from one part of the structure to another is not deleterious as it is under the ultimat pressure that is being maintained by the compressor.

In Fig. 3 the elements of this refrigerant apparatus are combined wherein the housing 42 encloses the electric motor prime mover 43 which carries the shell 44 of the compressor within its rotor 45. The shell, being in this instance the compressor rotor, is provided with the closed tubular extension 46 forming the intake chamber or vortex of the compressor and having the valve opening 41 which periodically connects the port 48 for admitting a metered portion of liquid from the liquid supply pump 49 to the intake chamber. The chamber 48 is in communication with the reservoir 50 in the bottom of the housing through the vertical pipes 5|.

Owing to the fluid pressure on the liquid in the reservoir the liquid chamber 49 is continuously supplied with liquid through these passages.

The vaporized refrigerant could be metered into the intake chamber through the valve opening 41 which would be similar to .the function of the structure shown in Fig. 2 but it is preferred in this. instance to employ the spring loaded check valve 52 which is biased inits closed position until a predetermined suction is developed in the intake chamber, then it opens and admits the vaporized refrigerant which is drawn from the evaporator in the refrigerating system through the pipe 53. This spring loaded check valve may vary in opening in accordance with any variation that 'may occur in the dedischarge line 54, which conveys the compressed refrigerant back to the refrigerating system.

The core 55 of the compressor is the nonrotary element in this modification and is supported on the universal joint 55 seated on the pedestal 51 formed as an integral part of the base of the housing. This universal joint is made up of two members 58 and 59 each having a depending key 68 and disposed at 90 to each other. The key 50 of the member 58 engages a complementary slot in the pedestal 51 while the key 6! in the member 59 engages a complementary slot in the member 58. These keyways permit the axis of the core to swing in a path concentric to the axis of the shell rotor but prevent the core from rotating. The key 5| may if desired be formed integral with the core 55, thereby' eliminating the member 59 of the universal joint.

It should also be noted that the coacting helical threads of the shell rotor and core member of this modification are spirally formed so that they taper from the discharge to the intake end. With this form of thread the axis of the core is gyrated in a conical path rather than a cylindrical path as when the threads are formed in a straight helix. The spiral or. tapered helical threads necessitate the formation of the spherical engaging surfaces between the elements of the universal joint 55 as illustrated in the drawing. Again the tapered shape of the core member 55 prevents it from moving upwardly.

Thus in Fig. 3 the action of the valves, one

depending upon motor rotation and the other depending upon the suction developed by the compressor due to the rotation, again produce a pulsating discharge of the compressor and the elements have been combined in a simplified compact structure. a

The volume of the pockets formed by the coacting surfaces of the rotor and stator may vary as they progress from one end of the compressor to the other. If these pockets reduce in volume as 'they approach the discharge end the vaporized refrigerant will naturally be compressed as it is being conveyed therethrough. If on the other hand they remain as a fixed volume the refrigerant will merely be conveyed by the pump and compressed by accumulation.

The structure illustrated inFig. 4 is a compact compressor unit wherein 52 represents the lower housing section having the spider 53 cast integral therewith and which is arranged to support the motor rotor 66 and the shell rotor 55 of the compressor. The top of the body of the spider is stepped as indicated at 66 and the The stator of the motor is supported on the seats I5 on the upper perimeter of the housing bottom is provided with a depending cylindrical .sleeve 51 for carrying the rotary sleeve 65 of the compressor.

The lower end of the motor shaft 68 is of reduced diameter and is pressed into a hole in the axial center of the shell as shown at 59. The end 10 of the shaft engages the top of the core member H of the compressor to prevent it from moving upwardly. d

A fianged collar I2 bolted to the top of the body of the spider is arranged to retain collar.

bearing 13 which is also provided with an integral radial flange 14 for carrying the end thrust of the rotary assembly. Thus the weight of the rotary assembly is carried by the step bearing of the spider and the engagement between the end of the shaft 10 and the core II of the compressor retains the latter in position.

52 and is enclosed by the hood 15 which. is provided with the centrally disposed open;r ig TI for discharging the vaporized refrigerant from the compressor to the refrigerating system.

A plurality of ports 18 are provided in the wall of the shell 85 for connecting its vortex 19 with the intake passageway 80 at all times. The other end of the intake passageway is connected through the spring loaded check valve 8| to the refrigerant inlet 82. This check valve permits the flow of the refrigerant from the refrigerating system to the compressor when a suction is created therein but prevents its return when the compressor is not operating.

83 represents an injector centrally disposed within the passageway 80 and having an orifice 84 directed toward the vortex of the compressor. The injector is connected by the pipe 85 to the bottom of the liquid reservoir 85 which is divided by the vertically disposed annular partition 81 extending above and surrounding the lower or discharge end of'the rotary shell 65.

the core H and the surface of these helical threads coact in surface contact to form individual pockets therebetween which are carried from the vortex 18 to the lower end of the shell as these coacting surfaces roll in surface contact when the members are subjected to relative rotary movement.

The rotary movement of the shell creates a suction within the vortex and draws refrigerant thereto which is carried down by. the pockets formed between the helical threads and is discharged into the liquid, the surface of which ispreferably well above the upper edge of the annular partition. Continued operation of the compressor builds up a pressure within the hood I5 and on the surface of the liquid in the reservoir. This pressure is efiective in forcing the liquid up the pipe 85 to the injector 83 where it is discharged out the orific 84 into the passageway 80 to the vortex where it is carried through the compressor with the refrigerant and is discharged into the sump formed by the annular partition 81. The vaporized refrigerant rises up through the liquid to the surface thereof. The orifice 84 of the injector is sufiiclently large to discharge the proper amount of liquid for sealing slip or backwash of the fluid and prevents material wear of the coacting surfaces, which is a material advantage.

The compressor has a tendency to emulsify the small portion of liquid that is circulated with the refrigerant. For this reason the bottom of the reservoir is partitioned by the annular wall 81. The emulsion discharged from the come pressor rises up through the liquid and the vaporized refrigerant passes off. The liquid outside the partition wall 81 is not emulsified and is therefore preferable for use as the circulating medium, which explains the reason for .the position of the pipe 85 leading to the injector. If desired this injector may be provided with a variable orifice for discharging the liquid at different rates, thereby changing the volumetric capacity of the compressor. This may be accomplished in the present structure by the relative position of the pipe 85 which may be raised or lowered with respect to the orifice 84 thereby changing the degree of the opening.

I claim:

1. In a refrigerating apparatus, the combination of an enclosed casing adapted to contain a refrigerant under pressure and providing a sump for a liquid, a pump arranged to discharge into the casing and comprising a tubular mem ber and a gyrating core member in telescopic relation with coacting helical threads, the tubular member having one more thread than the core member and forming a series of pockets longitudinally of the members, means for rotating one of the members relative to the other to cause the pockets to travel axially of the members, means for supplying refrigerant in vaporized form to the pump, and means for admitting a measured quantity of liquid from the sump to the pump at spaced intervals in timed relation with the rotation of the pump, the spaced quantities of liquid in traveling through the pump acting as hydraulic pistons which create suction to draw quantities of the refrigerant from the refrigerant-supply means and force it through the pump into the casing, thereby delivering a progression of liquid quantities spaced apart by quantities of refrigerant.

2. In a refrigerating apparatus, the combination of an enclosed casing adapted to contain a refrigerant under pressure and providing a sump for a liquid, a fluid pump mounted within the casing and comprising a tubular member and a gyrating core member in telescopic relation with coacting helical threads, the tubular member having one more thread than the core member and forming a series of pockets longitudinally of the members, means for rotating one of the members relative to the other to cause the pockets to travel axially of the members and discharge the fluid into the casing, means for supplying refrigerant in vaporized form to the pump, and means for admitting a measured quantity of liquid from the sump to the pump at spaced intervals in timed relation with the rotation of the pump, the spaced quantities of liquid in traveling through the pump acting as hydraulic pistons which create suction to draw quantities of the refrigerant from the refrigerant-supply means and force it through the pump into the casing, thereby delivering a progression of liquid quantities spaced apart by quantities of refrigerant.

3. In a refrigerating apparatus, the combination of an enclosed casing adapted to contain a refrigerant under pressure and providing a sump for a liquid, a pump arranged to discharge into the casing below the level of the liquid in the sump and comprisin a tubular member and a gyrating core member in telescopic relation with coacting helical threads, the tubular member having one more thread than the core member and forming a series of pockets longitudinally of the members, means for rotating one of the members relative to the other to cause the pockets to travel axially of the members, means for supplying refrigerant in vaporized form to the pump, and means for admitting a measured quantity of liquid from the sump to the pump at spaced intervals in timed relation with the rotation of the pump, the spaced quantities of liquid in traveling through the pump acting as hydraulic pistons which create suction to draw quantities of the refrigerant from the refrigerant-supply means and force it through the pump into the casing, thereby delivering a progression of liquid quantities spaced apart by quantities of refrigerant.

members relative to the other to cause the pockets to travel axially of the members, means for supplying refrigerant in vaporized form to the pump, means for admitting a measured quantity of liquid from the sump to the pump in timed relation with the rotation of the pump, the quantity of liquid being less than the volumetric capacity of the pump and when traveling through the pump acting as hydraulic pistons which create suction to draw quantities of the refrigerant from the refrigerant-supply means and force it through the pump into the casing, thereby delivering a progression of liquid quantities-spaced apart by quantities of refrigerant.

5. In a refrigerating apparatus, the combination of an enclosed casing adapted to contain a refrigerant under pressure and providing a sump for a liquid, a pump arranged to discharge into the casing and comprising a tubular member and a gyrating core member in telescopic relation with coacting helical threads, the tubular member having one more thread than the core member and forming a series of pockets longitudinally of the members, means for rotating one of the members relative to the other to cause the pockets to travel axially of the members, means for supplying refrigerant in vaporized form to the pump, means for continuously admitting a measured quantity of liquid from the sump to the pump in timed relation with the rotation of the pump, the quantity of liquid being less than the volumetric capacity of the pump and when traveling through the pump acting as hydraulic pistons which create suction to draw quantities of the refrigerant from the refrigerant-supply means and force it through the pump into the casing, thereby delivering a progression of liquid quantities spaced apart by quantities of refrigerant.

6. In a refrigerating apparatus, the combination' of an enclosed casing adapted to contain a refrigerant under pressure and providing a sump for a liquid, a pump arranged to discharge into the casing and comprising a tubular member and a gyrating core member in telescopic relation with coacting helical threads, the tubular member having one more thread than the core member and forming a series of pockets longitudinally of the members, means for rotating one of the membersv relative to the other to cause the pockets to travel axially of the members, a sup- 4. In a refrigerating apparatus, the combina- V ply of refrigerant in vaporized form, and valvular means for alternately admitting a measured quantity of liquid from the sump to the pump and refrigerant from said supply in timed relation with the rotation of the pump, the alternate quantities of liquid in traveling through the pump acting as hydraulic pistons which create a suction to draw. the refrigerant through the 'valvular means when opened to the refrigerant supply and force it through the pump into the casing, thereby deliveringv a progression of liquid quantities spaced apart by quantities of refrigerant.

7. In a refrigerating apparatus, the combination of an enclosed casing adapted to contain a refrigerant under pressure and providing a sump for a liquid, a pump arranged to dischargeinto the casing and comprising a tubular member and a gyrating core member in telescopic relation with coacting helical threads, the tubular member having one more thread than the core membet and forming a series of pockets longitudinally of the members, means for rotating one' of the members relative to the other to cause the pockets to travel axially of the members, means for supplying refrigerant in vaporized form to the pump, and a rotary valve operated in timed relation with the rotation of the pump for admitting a measured quantity of liquid from the sump to the pump, the spaced quantities of the liquid in traveling through the pump acting as hydraulic pistons which create suction to draw quantities of the refrigerant from the refrigerant-supply means and force it through the pump into the casing, thereby delivering progression of liquid quantities spaced apart by quantities of refrigerant.

8; In a refrigerating apparatus, the combination of an enclosed casing adapted to contain a refrigerant under pressure and providing a sump for a liquid, a fluid pump mounted within the casing and comprising a tubular member and a l 5 the members and discharge the fluid into the casing, a closed extension on said tubular member, a chamber surrounding said extension and having communication with the sump below the liquid level, registering means in the walls of said extension and chamber for admitting a measured quantity of liquid from said chamber to said extension at spaced intervals in timed relation to the rotation of the tubular member, and valvular means for admitting refrigerant in vaporized form to said extension,the spaced quantities of liquid in traveling through the pump acting as hydraulic pistons which create suction to actuate said valvular means and draw quantities of refrigerant therethrough and force it through the pump into thecasing, thereby delivering a progression of liquid quantities spaced apart by quantities of refrigerant. v

10. In refrigerating apparatus, the combination of an enclosed casing adapted to contain a refrigerant under pressure and a sump for liquid, a fluid pump comprising a pump housing having an intake and discharge opening, a sleeve member rotatably mounted in said housing with its ends adjacent the intake and discharge openings, a core member in said sleeve, coacting helical threads on said members, said sleeve having one more thread than said core forming a series of pockets longitudinally of the members, means for holding saidcore within the sleeve against longitudinal and rotary movement and permitting its axes to move in an orbital path, means for rotating said sleeve, means for admitting refrigerant in vaporized form to the intake of said pump, a liquid pumping medium contained within the sump of the reservoir, and valvular means for periodically admitting a predetermined quantity of said liquid to the intake end of said gyrating core member in telescopic relation with I coacting helical threads, the tubular member having. one more thread than the core member and forming a series of pockets longitudinally of the members, means for rotating the tubular member to cause the pockets to travel axially of the members and discharge the fluid into the casing, a closed extension on said tubular member, a chamber surrounding said extension and having communication with the sump below the liquid level, registering means in the walls of said extension and chamber for admitting a measured quantity of liquid from said chamber to said extension at spaced intervals in timed relation to the rotation of the tubular member, and means for supplying refrigerant in vaporized form to said extension, the spaced quantities of liquid in traveling through the pump acting as hydraulic pistons which create suction to draw quantities of the refrigerant from the refrigerant-supply means and force it through the pump into the casing, thereby delivering a progression of liquid quantities spaced apart by quantities of refrigerant.

tion of an enclosed casing adapted to contain arefrigerant under pressure and providing a sump for aliquid, a fluid pump mounted within the casing and comprising a tubular member and a gyrating core member in telescopic relation with coacting helical threads, the tubular member having one more thread than the core member andforming a series of pockets longitudinally of the members, means for rotating the tubular member to cause the pockets to travel axially of pump in timed relation with the movement of the sleeve, the spaced quantities of liquid. in traveling through the pump acting as hydraulic pistons which create suction to draw quantitie of the refrigerant from the refrigerant supply means and force it through the pump into the casing, thereby delivering a progression of liquid quantities spaced apart by quantities of refrigerant.

11. In a fluid pump, the combination of a pump housing having an intake and discharge opening, a sleeve member rotatably mounted in said housing with its ends adjacent the intake and discharge openings, a core member in said sleeve, coacting helical threads on said members, said sleeve having one more thread than said core and forming a series of pockets longitudinally of the members, means for holding said core within the sleeve against longitudinal and rotary movement and permitting its axes to move in an orbital path, and mean for rotating said sleeve.

12. In a pump, the combination of a casing having intake and discharge openings, a, longitudinally disposed tubular member in the casing with its ends adjacent the intake and discharge openings, 9. core member within said tubular member and held against longitudinal movement therewith, coacting helical threads on said members, the tubular member having one more thread than the core member, said threads forming a series of pocket longitudinally of the members,

one of said members being non-rotatable and the other being rotatably supported relative thereto to produce progressive travel of said pockets from one end of the tubular member to the other, and means for confining the movement of the longimembers, the tubular member having one more 10 thread than the core member, said threads forming a series of pockets longitudinally of the members, the tubular member being rotatably supported relative to the core member to produce progressive travel of said pockets, from one end of the tubular member to the other, and means for supporting the core member to oscillate with its longitudinal axis moving in a conical orbital path.

ARTHUR A. ALDRIDGE.

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