US2394953A - Mechanical refrigerating system - Google Patents

Description

Feb. 12, 1946. R. w. WATERFILL MECHANICAL REFRIGERATING SYSTEM 2 Sheets-Sheet 1 Original Filed Aug. 3, 1940 n Ei Feb. 12, 1946. R. w- WATERFILL 2,394,953

MECHANICAL REFRI GERATI NG S YS TEM Original Filed Aug. 3, 1940 z'sheets-sheet 2v INVENTOR. /aoerf W. Wafevfw/ BY ferrara/JEVS' numeral Il designates Patented Feb. 12, 194e y UNITED STATES PATENTy OFFICE l i RZATING SYSTEM Robert W.

Waterilll, Buensod-Stacey,

Montclair, N. J., assign Incorporated, New York, N. Y.,

or to' a corporation of Delaware 350,785. 1943, Serial No.

3, 1940, Serial No. application July 24.

1 claims. (ci. cs2-rus Serial No. 350,785, filed August 3, vglih Patent No. 2,341,132 issued operation of mechanical retrigerating equipment. It is another object of the vide a refrigerating system The foregoing and other objects, as well as various features of the invention, will be more consideration of the com-evaporator unit of Fig. l; and

view, on an enlarged scale, ilrst stage of the -rst com- Pig. 3 is a Sectional ot a fragment of the pressor unit of Fig. 1.

In the drawings. and

a casing which is of cylindricalform having legs 'Il adapted to rest upon any appropriate foundation so that the casing may serve as the elective base of the mareferring ilrst to F'ig.y 1,`

preferably 5o are provided with tending iins Il, and are interconnected 'with a water-box' I Il covering the right-hand end of the casing as viewed in Fig. 2. This portion of casing Il accordingly orator of the system in which refrigerant liquid may be vaporized to abstract heat from water or any other desired medium circulated through the tube bank. At this point it will be noted that design and provides both supply and discharge connections be water-box I 4 is of conventional tween the ends of tubes I2 and circulating lines (not shown) for a liquid to be cooled. v

The ilrst compressor unit l5, comprising eomf pressor stages A and B, motor I6 and accessories, lis housed in the leithand end portion of the casing I0 (Fig. 2)- and in direct communication with the evaporator. In the operation of the system, stage A serves to withdraw refrigerant vapor from the evaporator portion of the casing, to compress the vapor to a certain extent, and to discharge it over and through the motor I8 to cool that, element. The second stage, B, withdraws the partially compressed vapor from serves as the compressor housing, further compresses-the vapor, and discharges it into a, manifold I1 which is bolted to the end of the casing.

In the preferred construction, a second casing Il, again of cylindrical form, is mounted atop the combination evaporator-compressor unit, the second casing having legs I9 welded or otherwise secured to its underside and resting upon similar legs 2l amxed to the upper part of casing In. The second compressor unit 2Iof the system, including compressor stages C and D, their common driving motor 22 and accessories, is housed l in an end of casing It immediately above the nrst compressor unit Ilin casing I0; and the end of casing -Il is covered by a manifold 23. When the system is operating, the partially compressed rei'rigerant vapor discharged from stage B o1' the unit passes throughmanifold I1, fitting 24, and manifolds into stage C, is further compressed therein, and is then discharged over and through the motor 22 to cool that element. The last stage, D, withdraws partially compressed, vapor from that part of casing I8 which serves as a housing for the second compressor unit. raises the -pressure o f thevapor to a desired nal value, and discharges it into the remaining portion of casing I8.

The last-mentioned casing portiony is adapted of the condenser of `the and in it is housed a bank of tubes 21 nrst compressor a'large-number of surface exserves as the shell ofthe evape their common driving i that Prt 0f Casing l0 which rerrigerants, such vapor may pass from which carry a large n ber of surface extending ns 2t, and which have their ends interconnected with the water-box 29. Here again the water-box serves its conventional function providing both supply and 'discharge connections between the ends of tubes il and circulating rines (not shown) for condenser cooling Accordingly. thecompressed vapor discharged from stage D passes over the bank of tubes, gives up its heat to water circulating through the and is condensed, the result- Cil ing refrigerant collecting in the baseer the shell (casing it), whence it may evaporator through conduit iii for re-use.

'The reirigerating machine which has been generaliy described above is primarily designed to operate with one ci the so-called low-pressure as trichloro-triuro-ethane or the like. These substances, as is well recognized in the art, are almost ideally suited to centrifugal compression. Accordingly, each of the compresser units i5 and 2i includes two stages of centrifugal compression each comprising an impeller adapted to be driven directly by the motor oi the unit, and a diffuser surrounding the irnpeller, the latter element serving in the wellunderstood manner to convert the velocity pressure of vapor issuing from the impeller into a static head. Ilhese two units arey so nearly identical in basic design that a consideration of one of them will sumce to bring out the features of both and the manner in which they are mounted in their respective casings. 'For this purpose the :first compressor unit l5 and its mounting in the evaporator casing i0 will be described in detail.

In assembling the unit l5, and starting with stage A, the inner half 32 of the diffuser (generally designated S3) is slipped over the shaft 3ft of motor it, and its iiange 35 is bolted at 36 to a flange tl of the motor housing. it will be seen that the flange 35 is formed at the rear end of a spider 3d which comprises an integral part of the diuser element 32, and that this spider has a series of openings te through which some through and over the windings of the motor it to cool those parts. If itk has not already been set in place, the gland i2 (Fig. 3) is slipped over the shaft 3G andI element 32'to provide a labyrinth packing around the shaft at this point.

The impeller M is next fitted and keyed to the shaft, and a Spanner nut t5 is applied to the end of the shaft to hold the impeller in place.

It will be noted (Fig. 3) that this nut has smoothly rounded surfaces which complement those of the impeller,`whereby friction betweenthe refrigerant vapor andthe impeller may be minimized. After the impeller has been mounted, the outer half 66. of the diffuser 33 can be tted in place, and bolted to the inner half 32 at t1. Finally, the inlet guard 48 is boltedor otherwise secured to the diffuser element 116. It will be noted at this point (Fig. 3) that the surface of the inlet guard is smoothly rounded, and is so designed as 'to complement the adjacent surfaces of the inlet of the impeller, all to the end that friction between the refrigerant vapor and the parts of the machine may be kept as low as possible. While the inlet guard must not touch the impeller, the clearance between these parts is small, and the guard is provided with a series of labyrinths 49 which effectively prevent the shortcircuiting of any substantial volume of vapor the outlet lill of the diuser is bolted at 63 to the diusen from the discharge of the impeller d around the inlet guard to its inlet.

The assembly of stage similar to that of stage A. Specifically, and referring to Fig. l, the inlet guard 5l is first applied to the inner half 52 of the diffuser (generally designated t) that inner half is slipped over the motor shaft 34, and its flange '5d is bolted at 55 to the ange et of the motor housing. Here, again, it will be noted that the `flange bd is spaced from the main body of the diiuser by a spider, the spaces between the arms ti of the spider again allowing for the now of vapor through the motor windings and into the second stage impeller, The impeller til is then ntted and keyed to the shaft 315i, and a nut t@ is applied to secure the impeller in place. When this has been done, some adjustment of the inlet guard 5l may be needed to insure that the guard and theimpeller do not touch. Here, again, the outer surface of the guard is smoothly rounded to complement the surface of the impeller inlet; and the guard is provided with labyrinthe to retrict the ow of vapor between that guard and the adjacent surface of the impeller. rThe assembly ci the compressor unit it is completed by the application of the outer half til of the dinuser, this element being bolted at 6l to the inner half 52 (Fig. l).

t is evident that the first compressor stage A must handleva larger volume of refrigerant vapor B, the volumetric difierence being accounted for by the fact that the vapor is partially compressed in the first stage before it is delivered to the second stage. Accordirigly,v and as is shown in Fig.` l, the diffuser et' and the impeller Ml of stage A are somewhat larger than the like parts of stage B.

It will be noted that the two impellers are mounted directly upon the motor shaft and are supported by the bearingsior that shaft (not shown). Eachv of these bearings is provided with an independent lubricating system 62, which may be constructed in accordance with the disclosure of Patent No. 2,266,107, dated December 16, 1941. Reference may be had to that patent for more complete details of the lubricating system and its manner of operation. The prime difference between the system there disclosed and the one here shown lies in the fact that the oil-settling chambers t3 are mounted directly upon the frame of the motor i6, rather than upon the casing of the unit.

The assembled compressor unit i5 is of such size and shape that it may readily be passed through the open end oi casing Il), and be slipped along rails td which serve bothto guide and to support it until the marginal flange 55 of the diffuser element 32 of stage A (Fig. 3) .forces a packing ring 66 into engagement with an annular flange tl formed on the inside of casing lll. The flange 68 of the dii-user element 52 of stage B may then be bolted to the flange 69 of the casing, the bolts 10 serving to force the entire unit endwise into the casing and to squeeze the packing ring 66 between the flanges 65 and 61 whereby to form a leak-tight joint between the compressor unit and that part of casing I0 which serves as the shell of the evaporator of the system. Finally, the manifold l1 may be bolted in place, as indicated at 1I, to cover the end of the casing.

The manhole 12 (Fig. 2) gives access to the inside of the casing I0 after the compressor unit has been inserted for making thenecessary elec- B of the unit is quite I C has a flange 83,

adapted to serve as anexpansion point between' trical'connectionsot the motor il, and for conthe two compressor units, the

nectlngnpipes 18 and 1I leading-from the settling chambers 63 of the ailingl systems to eyes which are mounted on casing Il. bulls-eyes give a visual indication ofthe quantity o1' oil in the lubricating systems. 'I'his oil may be supplied in the nrst instance, or more may be added, through illling cups 16 which are connected-with the bulls-eyes through pipes 11,

and, accordingly, with -the lubricating systems through the above-mentioned pipes 14. When all of the internal connections have been made the cover 18 may be applied to the casing over the manhole 12 to seal the unit at this point.

I'he basic design of the second compressor unit 2| is quite similar to that of the first unit I 5,'

as has already been pointed out. These diilerences, however, should be noted. Stage C of the second unit is assembled in substantially the same manner as stage A of the first unit; and the assembly of stage D follows that of stage B. Here, again, it will be evident that the stagcs are of progressively decreasing volumetric capacity, the impeller 19 and the diiuser 88 of the third stage C being of somewhat lesser diameter than the comparable parts of the second stage B, and the impeller 8| and the fourth stage D being oi' lesser diameter than the comparable parts of the third stage C.

The completely assembled unit 2| the procedure isI much like that followed in mounting the first compressor unit I5 in the evaporator casingft I0. 'I'he diiuser 88 of stage which is comparable in func tion to the flange68 of stage B, wherebyit may be bolted to an end flange 84 of the casing I 8, and the diffuser 82 flange 85 at its edge which is comparable to the flange 65 of diffuser element 32 of stage A. Accordingly, the bolts 86 serve to drive the entire unit into the casing, an`d to cause flange 88 to compress a gasket 81 against an annular internal flange 88 formed on the casing 8 to form a leaktight joint at that point. then be bolted at 80 to the end ofycasing I8.

When the foregoing steps have been completed, the electrical connections may be made to the motor 22, and the oil lines 9| and 82 may be connected to bulls-eyes mounted on the casing I8, these operations being accomplished through a. manhole which may later be covered to seal the unit. Neither these last-mentioned lmllseyes nor the manhole and its cover are shown in the drawings, but these parts may be identical with the comparable ones shown in Fig. 2, and further illustration and description are unnecessary.

'I'he various constructional diiferences between the two compressor units and their individua-.l

stages are -well illustrated in the drawings and need not be further described.

It is the usual practice in assembling a refrigerating machine of this kind to form two casings and to mount the small one I8 atop the large one I8. 'I'he compressor units are then assembled and inserted in their respective casings, after which the manifolds |1 and 23 are bolted in place. The manifolds may then be connected by the fitting 24, which preferably comprises a section of vcopper or brass tiibing having flanges at its ends for connection to the flanges of the caps i1 and 23, and a peripheral fold at some point between its ends. The tting is thus the bull's- Y These may be inserted through the open end of casing |8, and- The manifold 23 may fold collapsing or extending to take up an expansionv or contractiiled parent application, and

tion of the various parts.

'I'he constructional details of the tube banks "I2 and 21 of the evaporator and condenser, 4respectively, are fully disclosed in the above-idenneed not be repeated here. It sumces to say that the completed banks are so constructed and arranged that they may be inserted endwise into the casings I8 and |8. respectively, opposite the compressor units, and may be secured in place Aby the applicationof the water-boxes I4 and 28.

diil'user 82 of the of stage D has a right-angle --i vapor from the struction of the compressor 'Ihe operation of thecompressor units to withdraw vapor from the evaporator portion of the shell I0, and to discharge it at a higher pressure the condenser portion of apparent to those familiar with the art. Further details as to the-operation of the completed refrigerating unit may be had by reference to the aforementioned parent application.

lSince certain changes may be made in the conunits, and the arrangement of their constituent parts in the casings, it is intended that the foregoing shall be construed in a descriptive rather than in a limiting sense.

What I claim is:

, l. A refrigerating system comprising a tubular bank for a liquid to -be cooled, said portion of said casing and said bank being adapted toserve as the evaporator of said system; a compressor and its driving motor housed in said casing, said compressor being adapted to withdraw refrigerant vapor from the evaporator portion and to discharge it` through the other end of said casing; a second tubular casing, a bank of tubes in said second casing with the ends of such tubes disposed adjacent an end of said second casing, a Water-box` closing that end of said second casing and providing connections for circulating a cooling medium through said last-mentioned tube bank, said second-mentioned casing and tube bank being adapted to serve as the condenser of the system;'means for conveying compressed refrigerant vapor from the discharge ofsaid comsaid second casing; and means for returning condensed refrigerantV from said casing, means covering that end of said casing and providing supply and discharge connectionsy to said bank for a liquid to be cooled', said bank and the adjacent portion of said casing being adapted to serve as the evaporator of said system; a first compressor unit including a driving and its outlet arranged to e Partially compressed vapor from the other end of said casing; a second tubular casing, a second commotor housed in rst compressor unit, said second compressor draw vapor through one endof said second casing and discharge it within such second casing; a bank of tubes housed in said second casing with their ends disposed adjacent the other end of such secondcasing, means covering that other end of. said second casing said second tube bank, said second tube bank' and the portion of said second casing in which it is housed being adapted to serve as the condenser of said system; means for conveying partially compressed refrigerant vaporfrom the discharge of said first-mentioned compressor unit to the inlet of said second-mentioned compressor unit; and means for returning the condensed refrigerant from the condenser portion of said second casing to the evaporator portion of said iirst casing.

3. A refrigerating system according to claim 2, wherein each of said compressor y a pair of centrifugal impellers, one mounted upon each end of the shaft of its motor; and a diffuser surrounding each of said impellers, the first of said diffus/ers having its outlet arranged to discharge -partially compressed refrigerant vapor into the portion of the casing in which the unit is mounted and over and through said motor, and the second of said impellers being adapted to withdraw refrigerant vapor passing over and through said motor from the portion of the casing in which said unit is mountedK 4. A refrigerating system according to claim. 2, wherein each compressor unit comprises a pair of centrifugal impellers, one mounted upon each end of the shaft of said motor; and a diifuser secured to said motor and surrounding each of said impellers, each of said units being of such size and shape that it :may be passed endwise into the casing in which it is housed, one of said diffusers being adapted to be secured to an end other of said diffusers of such casing and the being disposed in leak-tight relation with a portion of said casing to prevent a back flow of compressed vapor from the discharge side of such diffuser.

5. A combination refrigerant compressor-heat exchanger unit comprising a tubular casing, a bank of heat exchange tubes adapted to be passed through one end of said casing and to be disposed with open ends of such tubes lying adjacent that end of said casing, a water-box secured to that end of said casing and providing supply and dis; charge connections to said tubes for a liquid medium, said bank and the portion of said casing in which it is housed being adapted to serve as a refrigerant heat-exchanger, and a compressor units comprises and providing connec.-

ioA

being arranged to unit housed insaid casing, said compressor unit comprising an electric motor, a plurality of centrifugal impellers mounted on the shaft of said motor, a diffuser lsurrounding each of said impellers, said compressor unit being adapted to be passed through the other end of said casing, one of said diifusers having means whereby it may be secured to such other end of said casing, and another of. said diffusers having a. peripheral flange; a packing ring adjoining the ange of the last-mentioned diffuser; and means on the inside of said casing also engaging said packing ring to form a leak-tight joint around the lastmentioned diffuser; said compressor unit being adapted to maintain a ow of refrigerant vapor through the heat-exchanger portion of said casing.

6. A compressor unit comprising a tubular casing having a peripheral iiange formed on its' a pellers; said motor, said impellers and said diffusers comprising a unit which is adaptedto be inserted into said casing through one of its ends; one of said diffusers having a peripheral fiange adapted to be secured to an end of said casing; the other of said diffusers having a peripheral flange adapted to oppose the iiange on the inside of said casing; and a packing ring adapted to -be compressed between the ange of the lastmentioned diffuser and the ange on the inside of said casing when said ilrst-mentioned diffuser is secured to said casing.

7. A refrigerant compressor comprising a tubular casing having an upstanding iiange formed on its inner surface between its ends; an electric motor; a plurality of centrifugal impellers mounted on ther shaft of said motor; a plurality of diffusers each surrounding one of said impellers; said motorimpel1ers and diifusers comprising a unit which is adapted to be inserted into. said casing through one of its ends; one of said diffusers having a peripheral flange which is adapted to oppose the ange on the inside of said casing; a packing ring between said iianges; the

' other of said diiusers having a' peripheral flange to form a seal therebetween.'

ROBERT W. WATERFILL.

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