|Publication number||US2286272 A|
|Publication date||Jun 16, 1942|
|Filing date||Apr 10, 1940|
|Priority date||Apr 10, 1940|
|Publication number||US 2286272 A, US 2286272A, US-A-2286272, US2286272 A, US2286272A|
|Inventors||William W Higham|
|Original Assignee||Universal Cooler Corp|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (22), Classifications (12)|
|External Links: USPTO, USPTO Assignment, Espacenet|
4 Sheets-Sheet 1 ATTORNEYS June 16, 1942.' A w. w. HIGHAM SEALED COMPRESSOR Filed April 10, 1940 4 sheets-sheet 2 W. W. HIGHAM SEALED COMPRESSOR Filed April l0, 1940 June la 1.942.
ATTORNEY a9 June 16, 1942. w, w .GHAM 2,286,272'.
Y SEALED COMPRESSOR Filed Apri; 1o; 1940 4 sheets-sheet ,5
ATTORNPY June 16, 194,2. w. w. HlGl-.IAM 2,286,272 v SEALED COMPRESSOR Filed April 10, 1940 4 sheets-sheet 4- INVENTOR J Patented June 1e, 1942 SEALED COMPRESSOR William W. Higham, Detroit, Mich., assignor to Universal Cooler Corporation, Detroit, Mich., 'a i corporation of Michigan Application April 10, 1940, Serial No. 328,849
This invention relates to a refrigerant compressor, and itis concerned particularly with a compressor of the so-called sealed type wherein the motor and compressing mechanism are located within a sealed housing.
It is the aim of the invention to provide a sealed compressor unit which embodies an improved structure capable of elcient trouble free operation. To this end, there are included among the objects of the invention the provision of a novel lubricating system for lubricating moving parts of the mechanism; the provision of a structure wherein such parts as the motor bearings, reciprocating parts such as pistons and connecting rods, and thrust bearings are located in a single chamber which incorporates no partitioning wall between portions of the chamber. A further object is the provision of an arrangement which, although parts are disposed within a sealed chamber, the valves associated with the pumping mechanism are readily accessible for service operations, and are so arranged that access may be had thereto without disturbing the remaining mechanism -within the sealed unit. Also, an arrangement is provided wherein the lubricating oil is cooled during the operation of the mechanism, together with `an arrangement which prevents lubricating oil from being forced back into the refrigerant line in the event :high pressure is developed within the sealed unit. The arrangement also provides for proper lubrication with a wideA variation of oil level in the unit, with the result that even if there should be a loss of considerable of thelubricating oil, the unit will operate satisfactorily. These and other objects of the invention will be more readily understood and appreciated as the detailed description is considered in conjunction with the accompanying drawings which show devices for carrying out the invention.
Fig. 1 is a vertical section taken through a compressor constructed in accordance with the invention showing some parts in section and some in elevation. i
Fig. 2 is a cross sectional view taken substantially on line 2-2 of Fig. 1 showing the web structure and some refrigerant passageways.
Fig. 3 is a. sectional view taken through the lower portion of the compressor substantially on line 3-3 of Fig. 1.
Fig. 4 is a detailed view showing the pump ar-y rangement forl the lubricating system with the .gasket in location and taken substantially on line 4-4 0f Fig. 1.
Fig. 5 is a view similar to Fig. 4 with the gasket substantially Y of the lubricating pump structure taken substantially on line 8- 8 of Fig. 5.
Fig. 9 is a partial view illustrating the rotor structure and looking in the direction of line 9 9 of Fig. l.
Fig. l0 is a detail viewl showing an inlet valve for the compressor. l
Fig. 11 is a sectional view taken substantially on line Il-Il of Fig. 1 showing other valve structure.
Fig. 12 is a detailed sectional view of the outlet valve of the compressor structure.
Fig. 13 is a side elevational view of the uni with part of the cover dome cut away to show electrical connections and also illustrating a mounting.
Fig. 14 is an enlarged sectional view showing a mounting.
The compressor unit takes the form of a body, which is preferably a casting, as generally illustrated at l and which is open at one end but which is closed by a dome 2, and which may be of suitably fashioned sheet metal. This dome, as shown in Fig. 13, has suitable terminals 3 passing therethrough for the supply of electric current y to the motor. The dome is secured to the casting as by means of bolts 4.
manner of a pump to accentuate ilow of the refrigerant therethrough.
'I'he end of the casting opposite the dome has a closing wall I0 arranged to receive a bearing H for a crank-shaft generally indicated at I2. The shaft has an end portion I3 journaled in the bearing; it has a` throw .|4, and the rotor 'I secitirfsd to the upper end of the shaft as indicated a The body in itsl intermediate portion is formed with an open web I6 having apertures Il therein as indicated, and its central portion is recessed for the reception of a bearing support I8 for a -with a passage 34.
bearing I9 in which anintermediate portion at the shaft is joumaled. This 'support is secured to the web by suitable means such as cap screws as indicated. Connecting` rods 20 are mounted ton rod is' designed to rest upon a free ring or" bushing 23, and the connecting rod is counterbalanced as at 24 to bring its center of gravity within the periphery of the bushing 23 to eliminatev any tipping action of the connecting rod. The result is a self-supporting rod with no side thrust on the piston. 'I'he upper connecting rod is similarly counter-balanced and it rests upon the lower connecting rod with no resulting side thrust on its piston. In this connection it will be understood that the unit is designed to operate in an upright position, as shown in Figs. 1
Before proceeding with the lubricating system, it is thought that it would be well to trace the flow of refrigerant through the unit. The body casting is provided with a recess 25 over which er strip or plate of metal 54 overlies the valve 52 but is spaced from its intermediate portion .and is held against the ends of the valve by a spring 55 which is stronger than the valve plate 52. In normal operation there is suiiicient clearance between the center portion of the valve 52 and the member 54 so that only the valve 52 flexes, but in the event of a heavy charge or slug vof oil the valve 52 and plate 54 may shift bodily away from the plate 43 against the action of the an in let fitting 26 is to be bolted, and which ilti ting includes a shut-off valve which may be closed by the turning of the valve piece 21 normally closed by a cap 28. A gasket is disposed between the inlet fitting and the body, and it is preferably provided with a screen 30. A tube 3| leads from the chamber 25 to a point near the bottom and below the .normal levelof the oilas indicated. The refrigerant gases entering at 3| have free access to the entire interior of the unit and can pass upwardly through the openings I1 in the web I6 and through the openings 8 in the rotor to the top of the unit. From this upper portion of the unit the gases pass to the two cylinders and a descriptin of 'the passageways to one cylinder and through the same will suffice for both cylinders, as they are duplicates and have the same reference characters applied to like parts.
- at 66, connects to an oil outlet tube 61.
A conduit 32 opening in the upper portion'of the t unit communicates with a passage 33, which joins From this point the gases pass into the cylinder 22, are compressed, and then pass from the cylinder in compressed condition into a passageway 35 -which joins with a passage 36 and which extendsto an outlet chamber 31. An outlet valve 38 is bolted to the body casting over the chamber 31 and this valve may be closed if desired' by means of operating the valve piece 40.
'Ihe valve structure-for controlling' the iiow of refrigerant to and from each cylinder is shown in Figs. 10, 11 and 1'2'. A reed valve member 4| is located on the body casting asby means of pins 42 and over this reed is positioned a plate 43, and over the plate is positioned a cap 44 having a dividing partition 45. Passageway 3 4 leads to an aperature 46 in the plate 43 and into chamber 41' of the cap. The plate 43 has an aperture 46 leading from the chamber V4'l to the cylinder.
The reed valve opens the port '46 for the inlet of refrigerant as the piston moves the section stroke and closes the port 46 on the compression stroke.
The plate 43 has an outlet-aperture 4l leading to chamber Il which Joins with the eway 36 stronger spring 55. A seal in the form of a wire 56 may hold the screws from rotating following an initial set at the factory. I
As pointed out above, the unit is designed to operate in an upright position, and accordingly a thrust bearing arrangement is provided at the lower end of the shaft. This thrust bearing arrangement also embodies a rotary pump. As shown in Fig. 6, the bearing II is just a little short of extending entirely through the bottom portion of the casting and a member 60, which may be a bronze disc, is associated with the end of the shaft and it takes the thrust load in that it bears upon the closing tap 6I secured to the body with an intervening gasket 62, as indicated. 'I'his bronze disc is eccentrically located on the bottom of the shaft as by means of two pins 63 and the eccentricity is justgabout the thickness of the bearing. Accordingly, the bronze disc functions within the confining wall of the aperture in the housing. The bottom of the housing is provided with three milled slots, one of which, as indicated at 64, connects to an oil inlet passage 65 in the casting; one of which, as This tube is located in an aperture drilled -in the casting and then its lower end is expanded as at 68 against the screw threadsformed in the aperture to permanently set and locate the tube. The
central milled slot 69 is provided with a follower I0 acted upon by a spring 'II positioned'in part in a recess 12.
The gasket 62 has a laterally extending opening 1,3, which is positioned off the center l'nie as shown, and embraces the inlet slot 64 and the slot 63, but seals oifthe outlet slot 66. Thus oil cannot be trapped back of the follower-`l0, as this space is connected to the inlet. AccordinglyV as Fig. 4 is considered, bearing in mind that the direction of rotation is clockwise, the structure provides a rotary eccentric pump wherein oil is caused to ow into the low side through the slot 64 and is pumped out the high side through the slot 66, with the division maintained by the sealing follower I0 which reciprocates in irlctional engagement with the periphery of the disc 6l.
The bearing is provided with a neuen slm;`
3|) which opens into the high side of the pump arrangement as indicated in Figs. 4 and 5 so that oilis also pumped into this helical slot and upwardly through the bearing II to provide lubrication at this point. 'I'he upper end of the slot 63 opens into a space 8| deflned by the bearing ring 23, and the connecting rod has a passageway 32 leading to outlet ports I3 in its bearing surface. Accordingly, in the operation 'of the device. the eccentric pump causes a positive flow of oil up through the passageway Il. thus lubrithrough a port 6I in the plate 43. The.v outlet 15 leating the bearing [II-and throughthe me- Awhich, in effect, forms a gutter into which the oil collects. The bearing support I8 has al passageway 86 which leads to the lower portion of the bearing I9, and the bearing I9 has a helical groove 81 which causes the oil .tomove upwardly as the shaft rotates to lubricate this location.'
'Ihe pistons and their .pins are also lubricated Afrom this forced feed arrangement. It will be observed (Fig. 2) Athat the-gutter 85 extends laterally on opposite sides, thus providing reservoir extensions 88 into which the oil flows. The ends of these extensions are elevated as at 89, and downwardly extending' oil passages 98 are provided, continuations of which at 9| communicate to the cylinders. Oil thus flows into the refrigerant ows into the unit and is discharged into the oil Vby the tube 3|. This sets up an agi- .tation 'of the oil and it is thereby cooled.' The refrigerant is drawn upwardly through the supportingl web IIiy through the rotor and down through the tubes 32. If any oil collects at the upper level around the stator 8, it may ow through the small apertures 32a and into the refrigerant lineso that it is carried back into the lower part of the chamber. Refrigerant is drawn, as above explained, through the several passageways and is compressed and passesout through the outlet Vpassages 36. The rotary pump positively pumps oil up through the helical groove 88 tolubrlcate the lower bearing and then up into the chamber 82 to lubricate the connecting rods. Oil is also positively pumped through the tube-61 and discharged' into the gutter 85.
cylinders and into the wrist pins which are hol low as shown and which are provided each with an oil passage 92 for lubricating the wrist pin journal. It might be said that the Wrist pins are each held in position by aspring clip 93.
This flows through passageway -86 into the helical gro'ove 81 to lubricate the upper bearing. The
oil is pumped upwardly by the action of the helical groove 81 and the turning of the shaft. The oil which fiowsthrough the outlets 98 moves downwardly and lubricates the piston and the piston wrist pins. The elevated portions 89 permit of collection of extraneous articles inv the lower level of the gutter so that such particles o may not ow through the passage 98'.
The clip engages opposite ends of the `wrist pin and one end is more or less keyed to the Wrist pin and it projects into a recess in the piston as shown at 93a. Thus the wrist pin is held against axial movement and against rotary movement,
and the oil hole 92 is thus held in a proper direction.
For the purpose of lubricating the valve structure, the passage 34 is formed to intersect both the passage 33 for the refrigerant gases and the oil passage 98-9 I. Dividing the oil and refrigerant gases is a plug 98 provided with a small tube The ow of the refrigerant is indicated in Fig. 1, sets up sort of .a Venturi action and. some of the oil vapors are drawn through the tube 91 i'nto the refrigerant. These oil vapors, and
'perhaps some small quantity of oil, is carried through the valve structure and into the compressed refrigerant line. This oil may pass ,through the system but is discharged back into the unit as the refrigerant enters through the pipe 3 I. y o
'I'he compressor may be mounted in a suitable manner and the one shown comprises a flexible or vibration dampening mounting. .iThe body casting may be provided with lugs |88 for the reception of supporting pieces having a plate |8I with a screwthreaded stud positioned in the` lug and a body of rubber or equivalent material |82 having a plate |83 with .a bolt or stud arranged to be secured to supporting brackets |84. The rubber body |82 islbonded to the plates |8I and |83.
'I'he inlet for the refrigerant is also provided with a small aperture 99 connecting theinlet chamber to the interior of the unit. This is a small bleed aperture. The major part of the refrigerant gases enter the unit through the pipe 3|=to-thus cool the oil.
In the event, however, that unduly high pressures develop Within the compressor unit for one reason or another, this pressure may bleed back into the inletline through the bleed aperture 99 and thus will not force oil back into the line through the tube 3|.
All of the working mechanism, including the motor, the bearings, both upper' and lower, the connecting rods and pistons,l are disposed in a single undivided chamber. There is no partition or dividing means within the chamber. Any excess oil which is-pumped into the gutter may merely flow over the same -and back into the sump in the bottom of the body casting. Notwithstanding the fact that a sealed unit is provided, in that all working parts are in a sealed chamber, the valves are accessible for service or removal. 'I'his is done by merely closing thelines by the service valves 211 and yI8 and then by de-V -taching the valve structure which includes cap 44, plate 43 and the valves themselves. After repair or,` replacement, the service valves may be opened and the apparatus is again in condition to operate.
1. In a refrigerant compressor ofthe sealed type, means forming a sealed chamber, a sub,-
stantially vertically disposed crank-shaft in the chamber, a substantially horizontally disposed cylinder wtih a piston therein, a connecting rod substantially horizontally disposed and pivotally connecting the crank and piston, means support-- ing the endof the connecting rod which surrounds the crank for taking the vertical load thereof, and a counter-balancing weight on the connectingv rod opposite the part which extends to the piston for placing the center of gravity of the connecting rod within the confines of the supporting means whereby the connecting rod is gravitationally stable to thereby eliminate gravity A thruston the piston.
In the operation of the compressor expanded 2. In a refrigerant compressor 4of the sealed type, means forming a sealed chamber, asubstantially vertically disposed crank-shaft in the chamber, a substantially horizontally disposed cylinder with a piston therein, a connecting rod substantiallyhorizontally disposed and connect-l ing the crank and piston, a ring positioned around the crank-,shaft and supporting the connecting rod, a counter-balancing weight on the connecting rod substantially opposite its extension to the.
piston arranged to place the center of gravity of the connecting rod substantially within the contour ofthe ring whereby the connecting rod is gravitationally stable on the ring.
3. In a refrigerant compressor of the sealed type, a body member, closure means forming a substantially sealed chamber, mechanism within the chamber including a crank-shaft and a motor for driving the same,
compressingv trically secured to the lower end of the shaft, supporting means under the disc for taking the vertical load of the shaft, means forming a housing for said member, a shiftable vane for said crank-shaft being disposed on a substantially vertical axis, means forming a bearing for the lower end of the crank-shaft, means forming a bearing for an upper portion of the crankshaft, a combined thrust and rotary pump member for the lower end of the crank-shaft for taking the vertical load and non-rotatably and eccentrically connected to the crank-shaft, means forming a housing for the thrust member, a
chamber includinga crank-shaft and a ,motor for driving the same, said crank-shaft being disposed on the substantially vertical axis, means forming a bearing for the lower nd of the crankshaft, means forming a bear' g for an upper portion of the crank-shaft, a combined thrust and rotary pump member for the lower end of the crank-shaft for taking the vertical load and non-rotatably and eccentrically connected to the crank-shaft, means forming a housing for the thrust member, a spring pressed vane having a wiping contact with an edge of the eccentric thrust member whereby a rotary pump is formed,
means for conducting lubricating oil to the inlet side of the vane, and a conduit connected to the other side of the vane and extending upwardly for discharging lubricating oil to the upper bearing, and a helical groovev associated with the lower bearing of the crank-shaft and opening on the outlet side of the vane for the pumping of oil through the lower bearing.v
5. In a refrigerant compressor of the sealed type, a body member, a closure member forming with the body member, a substantially sealed chamber, compressing mechanism within the chamber including a crank-shaft and a motor for driving the same, said crank-shaft being disposed on the substantially vertical axis, the body having an opening therein with a bearing for the lower end of the crank-shaft, the axial length of said bearing being less than that of the opening, means forming a bearing for an upper part of the shaft, a combined thrust and pump member non-rotatably and eccentrically lsecured to the lower end of the shaft and operating in said opening at the end of the bearing whereby the walls of the opening yform a pump housing,a shiftable vane wiping the edge of the thrust member, whereby a rotary pump is provided, an
wiping the edge of the eccentric member, means for introducing oil on one side of the vane, one or' more outlets forv lubricating oil on the opposite side of the vane, and means for conducting the lubricating oil from the outlets 4to parts to be lubricated.
'7. In a refrigerant compressor, means providing a sealed chamber, a body member, an oil sump, formation in the chamber, said body having an opening therein, a bearing in the opening, a shaft journaled in the bearing and disposed lsubstantially on a vertical'axis, said bear ing being axially shorter than the opening, a combined thrust disc and pump member eccentrically secured to the lower end of the shaft and operating in the opening at the end of the bearing, whereby the walls of the opening form v a pump housing, said disc resting upon a portion of the body memberto take the vertical load of the shaft, three slots in the body member and opening into said pump housing, a spring pressed conducting oil from the` outlet `to parts to be lubricated.
8. In a refrigerant compressor of the sealed type, a body member having a bottom enlargement provided with a bearing, a shaft having its lower end journaled in the bearing and arranged to run substantially on a' vertical axis, said shaft having a crank, a ring surrounding the crank and resting upon the enlargement, said crank being positioned above the enlargement to form a space confined by the ring, a passage extending upwardly in the crank, one
or more connecting rods on the crank, another passage extending to the surface of the crank,
and means for pumping lubricating oil upwardly through the bearing into said space confined by the ring and upwardly in the passage in the crank and out through the other passage for lubricating purposes.
9. In a refrigerant compressor of the sealed type, means forming a substantially sealed chamber, a crank-shaft arrangedV to run substantially on a vertical axis, means forming a bearing for the lower end of the crank-shaft, a
leading from the gutter to the lower portion of inlet for lubricating oil on one side of the vane,
anloutl'et for oil on the other side of the vane,
and a conduitextending from the. outlet upwardly and arranged' to discharge oil for the lubrication of the upper bearing.
6. In a refrigerant compressor, a shaft arranged to run substantially on a vertical axis, a
combined thrust bearing and pump member in the form of a disc non-rotatably and eccen-- the upper bearing, and a.- helical groove associated with the upper bearing for the movement of oil upwardly through the bearing for lubri eating purposes.
10. In a refrigerant compressor -of the sealed type, a body member, means forming a. substantially sealed chamber, a horizontally disposed cylinder in the body member, inlet and outlet means for refrigerant, compressing mechanism including a motor and crank-shaft disposed within'the chamber with the motor disposed in the upper part of the chamber and, with the crank-shaft disposed substantially on a vertical axis, means on the body member above the cylinder and below the motor for supporting a bearing for the shaft, said supporting means including a gutter formation, means for pumping lubricating oil from the lower portion of the body upwardly andfor discharging it into the gutter, and a passageway extending downwardly from the gutter and opening into the cylinder for the lubrication of the piston and cylinder.
1l. In a compressor ofthe sealed type, a body member, means forming a substantially closed chamber, a motor and compressing mechanism in the chamber and including a cylinder and piston, an inlet for refrigerant, an outlet for refrigerant, inlet and outlet valves forthe cylinder, a passageway for refrigerant gases leading from the 'interior of the unit to the cylinder, a'. lubricant 'passageway for feeding lubricant to an operating part, and means including a relatively small opening interconnecting the refrigerant passageway, and lubricant passageway, whereby movement `of the refrigerant gases draws oil vapors through said relatively small opening for conveying the same to the cylinder valve mechanism for lubricating the same.
12. In a compressor or the like, a conduit for a fluid such as lubricating oil or the like comprising, a body member formed with an opening having an enlarged part, the walls of the enlarged p'art having roughened surfaces, a tube extending in the opening and having a portion disposed in the llarge part of the opening and.
expanded therein with the roughened formation forming a corresponding and intertting forma.-
tion on the exterior of the expanded part cate and hold the tubel in position.
13. In a refrigerant compressor, means providing a sealed chamber, a body member, an oil sump formation in the chamber, said body member having a wall in which a shaft is journaled, an eccentric pump member on the' end of the shaft, means forming a housing for the pump member including the wall andclosure plate, three milled slots in a housing member and leadto loing into the housing, one side slot being con-
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US2450468 *||Oct 1, 1943||Oct 5, 1948||Cornelius Richard T||Motor-driven compressor|
|US2517367 *||Sep 24, 1946||Aug 1, 1950||Winkler Margenthaler Inc||Gas compressor|
|US2627170 *||Sep 27, 1948||Feb 3, 1953||Tresco Inc||Hermetic refrigeration compressor|
|US2628016 *||Mar 5, 1946||Feb 10, 1953||Tecumseh Products Co||Refrigerating apparatus|
|US2752088 *||May 20, 1952||Jun 26, 1956||Whirlpool Seeger Corp||Hermetically sealed radial compressor assembly|
|US2963216 *||Oct 9, 1958||Dec 6, 1960||Westinghouse Electric Corp||Refrigerating apparatus|
|US4549857 *||Aug 3, 1984||Oct 29, 1985||Carrier Corporation||Hermetic motor compressor having a suction inlet and seal|
|US4780067 *||Sep 28, 1987||Oct 25, 1988||Mitsubishi Denki Kabushiki Kaisha||Multicylinder rotary compressor|
|US4795316 *||Aug 3, 1984||Jan 3, 1989||Carrier Corporation||Compressor suction pulse attenuator|
|US5118263 *||Apr 27, 1990||Jun 2, 1992||Fritchman Jack F||Hermetic refrigeration compressor|
|US5931649 *||Jun 4, 1998||Aug 3, 1999||Copeland Corporation||Scroll-type machine having a bearing assembly for the drive shaft|
|US7566204 *||Dec 6, 2005||Jul 28, 2009||Sanyo Electric Co., Ltd.||Multicylindrical rotary compressor, compression system, and freezing device using the compression system|
|US7985054||Jun 4, 2009||Jul 26, 2011||Sanyo Electric Co., Ltd.||Multicylindrical rotary compressor, compression system, and freezing device using the compression system|
|US20060140802 *||Dec 6, 2005||Jun 29, 2006||Sanyo Electric Co., Ltd.||Multicylindrical rotary compressor, compression system, and freezing device using the compression system|
|US20090160209 *||Dec 21, 2007||Jun 25, 2009||Wilhelm Karmann Gmbh||Convertible top having over center backlight|
|US20090238710 *||Jun 4, 2009||Sep 24, 2009||Sanyo Electric Co., Ltd.|
|DE919593C *||Jul 12, 1952||Oct 28, 1954||Stempel Ag D||Schmiermittelzufuehrung fuer Kaeltemaschinen|
|DE1093629B *||Oct 17, 1958||Nov 24, 1960||Willy Hirche||Zungenfoermiges Ventilverschlussstueck fuer hochtourige Kaelteverdichter|
|DE1277278B *||Jan 28, 1961||Sep 12, 1968||Danfoss As||Motorverdichter fuer Kleinkaeltemaschinen|
|DE4112704A1 *||Apr 18, 1991||Nov 7, 1991||White Consolidated Ind Inc||Luftdichter kaelteverdichter|
|DE102008025321A1 *||May 27, 2008||Dec 3, 2009||Danfoss A/S||Refrigerant compressor, particularly semi-hermetic refrigerant compressor, has multiple star-shaped cylinders arranged around crankshaft, where cylinders are locked by cylinder head in each case|
|DE102008025321B4 *||May 27, 2008||Apr 3, 2014||Danfoss A/S||Kältemittelverdichter|
|U.S. Classification||417/372, 74/589, 92/154, 417/902, 417/419|
|International Classification||F25B31/02, F25B31/00|
|Cooperative Classification||F25B31/002, F25B31/023, Y10S417/902|
|European Classification||F25B31/00B, F25B31/02B|