US1718312A

US1718312A - Evaporator

Info

Publication number: US1718312A
Authority: US
Publication date: 1929-06-25
Anticipated expiration: 1946-06-25

Description

June 25, 1929.

T. SHIPLEY EVAPORATO Filed Jan 2l, 1927 3 sheets-sheet 2 F E 7N 2 E a .ll-.lner 1929. I T SHIPLE'Y .A 1,718,312

i EVAPORATOR Filed Jan. 21; 1927 s sheets-sheet 5 @ktm/naga,

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Patented June 25, 1929.

UNITED STATES PATENT oFFicE.

THOMAS SHIPLEY, OF YORK, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO YORK ICE MACHINERY CORPORATION, OF YORK, PENNSYLVANIA, A CORPORA- TION OF DELAWARE.

EVAPORATOR.

Application filed January 21, 19%?. Serial N'o. 162,574.

This invention relates to refrigeration, and particularly to the construction and arrangement of the evaporators. In the past the advantage of operating an evaporator flooded was fully understood, but efforts so to operate them have not proved uniformly successful and the installations have generally been limited to cases Where some type of receiver could be located above the evaporator and then feed it by gravity. A known arrangeinent is to make use of what is termed a suction trap as the reservoir Which feeds the coils, the separation of the vapor and the return of the liquid to the suction trap occurring through. the action of gravity.

The purpose of the present invention iste produce an installation in which a plurality of units may be operated in parallel, may be defrosted individually, may be adi usted individually for refrigerative effect, and in which substantially Hooded operation is insured, at all times.

The invention is particularly adaptable to hardening rooms for ice cream, cold storagzfje, and similaiplants, and may be also einboiflied inbrine tanks for freezing ice in cans, brine coolers and the like.

It has heretofore been proposed to circulate liquid refrigerant through an evaporator by a pump or equivalent means for the purpose of maintaininsij the evaporator substantially flooded, that is to say, tor tue purper-:e of insuring that liquid refrigerant penetrates throughout substantially the entire length oi? the evaporator. In such prior devices the receiver has been mounted above the evaporator, the idea being to keep the evaporator submerged in liquid by the existence of a static head rather than by the action of the pump alone.

The pre-:ent case is directed to a particular ouilmdimcnt of the positivo circulation idea, in which the refrigerant is so circulated 'that it first enters the top of the evaporator, flows thence downwardly through the evaporator and returns from the evaporator with sutilcient velocity to entrain with the liquid refrigerant the vapor formed in passage through the evaporator. The receiver then acts as a suction trap in which the liquid and vapor separate, the vapor passing to the suction line of the compressor and the liquid being recirculated by the pump.

This arrangement has various advantages. By making the circulation sufficiently rapid the liquid flow Will persist to the lower end of the evaporator' and Will be effective to entrain the evolved vapor and sweep it out of the evaporator even though a substantial portionof the cross section of the evaporator be not lled with the liquid but remain clear for the passage of the vapor. Another advantage is that When Athe pump is shut down the evaporator drains, producing a condition favorable to defrosting of the evaporator on occasion.

In order to .insure equal distribution of the refrigerant not only to different evaporators of a group but also to each element, such as the individual coils of each evaporatoi", use is made of overflow distributors, so contrived as to insure ap} 3i'oxiiiiately uniform feeding of all coils With liquid refrigerant. In order to regulate the action of the evaporators, particularlywhere a` plurality of these are connected up in parallel to a single compressor, use is made of a short circuiting lay-pass, by means of which effective circulation produced by t-he pump may be reduced at Will. This avoids any tlirottling of the liquid refrigerant in the circulating flor-J, and is an important feature, leading to smooth operation and close control.

aree practical embodiments of the invention are illustrated in the accompanying drawings, in Which,

Fig. lA is an elevatiA lowing; ncctions for tivo hardenl ic; rooms, fed n'ieans of a single refrigerant cycle. In this view the compressor, condenser and receiver are indicated by conventional diagram, in order to malte clear the pipe connections to 'these elements.

Fig'. 2 is a fragmentary view of one of' the coils of the evaporators illustrated in Fig. l.

3 is a transverse section of a distrib- "ating header on an enlarged scale, showing the eonstructbn of the flow distributors.

Fig. a a diagrammiatie elevation showing; the application of the invention to cold storage rooms.

Fig. 5 a diagrammatic section showing the application of the invention to a brine cooler.

Referring first to Figs. l, Q and 3, 6 represents a liquid cooling trap to Which liquid and its connections;

refrigerant comes by way of the pipe 7 and float valve 8 from a high pressure receiver. The purpose ol the float valve S is to maintain a constant level within the liquidcooling trap 6. The valve 9 is an ordinary stop valve in the liquid line.v The valve 10 controis an oil drain wherever it appears. Pipe 11 a suction connection Ifrom the trap 6 and leads to the interstage connection of a two stage compressor. rlhis coinpressor is indicated by the legend L P. appliedito its lower pressure cylinder, and the legend -H. P. applied to the high pressure cylinder. The condenser is indicated by the letter l and the high pressure receiver by the legend H. P. R. It is to be understood that the compressor is ot" any known variable capacity type. The compressor, condenser and receiver' are diagramniatically illustrated merely to show the evaporator connections clearly. No novelty is claimed broadly for the use oit a variable capacity compressor or for the particular arrangement ol the compressor- Iii 'fact these are subject to considerable cha-nge without depart ing from the inventive principle here involved..

inasmuch as Fig. 1 shows two cooling rooms connected up in parallel, the same Areference numerals will be applied to corresponding elements for each room designates i generally by the legends Room A and Room B.

Pipe 12 leads from the trap 6 byl way of stop valve 13 and float valve 14 to a suction trap 15. The purpose of the tloat valve lil to maintain a. constant levelotl liquid refrigerant in the trap 15. Leading from the bottom ot the trap 15 is a pipe 16 which is controlled by valve 17 and leads to a rotary pump 18 driven in vany desired manner. This pump discharges through valve 19 to a line 2() which leads to a distributing inanil'old 2l. A by-pass between the pipes 20 and 1G is controlled by by-pass valve 22. lior defrosting there is provided a hot gas connection 23 controlled by a stop valve 24C, and since during the detrosting operation the suction trap 15 might receive an excess of liquid refrigerant, a reversed float valve 25 is provided. The reversed float valve 25 controls flow through the pipe connection 26 back to the cooler 6.

Under normal conditions, as will be iinderstood, the trap 15 is at a lower pressure than the trap 6, but, will be later ex- ]gilained, this` pressure relation is reversed during defrosting, and consequently the valve 25 is provided and so arranged that it the level of liquid rises unduly high in the suction trap 15`it will open to permit flow through the pipe 26 back to the cooling trap 6.l This connection is provided with a hand operated stop valve 27` for emergency use, and there is also a direct drain connection from the suction trap 15 to the pipe 2G controlled by stop valve 28, which is normally closed.

The manifold 21 Aissimply a drum into which project distributing pipes 29 having a row oll graduated perforations 30 so designed that as the level of the liquid refrigerant in the maniiold 21 rises, the rate of outflow will be increased to compensate. There are a plurality oic pipes 29 in cach manifold 2l, one for each evaporator in the room. Thus in the manifold of Room A there are two sets of pipes and in Room ll there are three sets of pipes. Each pipe 29 leads to the distriliiuting manifold 31 ot an evaporator, consisting of a plurality of evaporator coils 32 extending` in a sinuous path and discharging` at their lower ends into an oil-take header 33. r1`he manifold 21, the manifold 31 and the header 33 are all in communication with. each other through a pressure equalizing connection 3&1 which enters the manifolds 21 and 31 above the liquid level therein. The headers 33 are connected by an olf-take line 35 with the suction trap 15 above the liquid level Vlihorein. The pipe controlled by a stop valve 37 leads to the suction connection 38. This is connected, of course, to the low pressure stage of the compressor.

Under normal conditions of operation the following valves are open, 9, 13, 17, 19, 27 and .37. .at the same time Vthe following valves are closed, 10, 241- and 28. rThe valve 22 is wholly or partly open according to the rate of circulatory flow desired to maintain the proper temperature in the corresponding coils 32. li" it be desired to delrost the coi of) and o( are closed, and the valve 24: is opeied to admit hot gas from the conii'iressor line to the pipe 20. At this time the pump 18 is,o'f course, out ot operation. The eli'ect is to displace the liquid refrigerant from the coils 32 causing it to flowl bach to the suction trap 15. Inverted iloat ralve 25 guardsagainst the accumulation ol an excess of liquid refrigerant in the trap 15. .Any such excess is returned to the trap G. This occurs be fause under the conditions jiust recited trap l5 is at coinprcssor discharge pressure. Thon defrosting is complete the valve 211 is closed and the

valves

37, 19 and 22 are again reopened and the pump 13 started.

lt will be observed that the coils of either room may be detrosted without interfering with ti e action of' the coils in the other room. and that the circulatory rate ior either room may be adjusted without affecting the circulatory rate for the other room. Concurrent adjustments of the capacity of the4 in eitherroom, corresponding valves 19,l

lOl)

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single stage compression. Consequently there is :no liquid cooling trap and no reversed float 'valve connection. Instead, the liquid line 42 from the receiver leads through a slop valve 43 to a float valve 44 which controls the liquid level in the suction trap 45, essentially identical in function to the suction trap 15. Liquid connection 46 leads through valve 47 and circulating pump 48 from which connection to the discharge line 5() is controlled by valve 49. The capacity of the pump 48 is controlled by by-pass valve 52. Pipe 50 leads to a distributin,r header There are a plurality of perforated distributor pipes 53, each of which acts to control the flow of liquidA refrigerant to a corresponding coil 54, of which only one is indicated in the drawing. These coils dis charge into a manifold from which pipe leads to tra-p 45.

The suction connection is shown at 57 and is cont-rolled by a stop valve 58. 59 is a valve controlling a hot gas connection for de frosting.

In Fig. 5 the application of the device to a brine cooler` for use in brine tanks and elsewhere, is illustrated. In this figure the parts are all substantially similar to those shown :in Fig. 4 and are similarly numbered. It will be observed that hot gas connections for defrosting are not necessary and are omitted. The brine tank is shown at 60.

In all three forms of the device, the flow to the various coils is equalized by an overllow or weir device, and the circulation is intentionally made so rapid that the vapor evolved in the evaporator can not rise through the descending current of liquid rei fri gerard, but is swept downwardly and out with the liquid refrigerant, from which it separates in the suction trap. The operation of the device, therefore7 entails a delinitely maintained circulation which nmy actually be as much' as four or live times the quantity of liquid refrigerant which 'can be evaporated in a single pass through the evaporator. This insures a practically llooded condition of the evaporator at all times so that the entire surface of the eviq'iorator is rendered unusually effcctive.

What is claimed is,m

l. In a refrigeratingr system, the combination of a receiver and an evaporator con nccted to establish a closed circuit, the evaporator offering a plurality of flow paths in 'parallel arrangement; graduated over-flow distril'iutingr means arranged to equalize the flow through said parallel paths; power circulating means for circulatingr liquid refrigerant in said circuit; a connection 'for withdrawingr vaporized refrigerant from the evaporator; and a connection for supplying liquid rcfrig'erz'int to said circuit.

2. In a refrigerating system, the combination of a .suction trap; an evaporator located in a position above the saine; connections establishing a closed circuit from the lower portion of the suction trap to the top of the evaporator thence downward through the emporator and from the bottom of the evaporator to the suction trap; power circulating means :for positively circulating liquid refrign erant in said closed circuit, in a quantity substantially in excess of that evaporaible in the evaporator whereby the vapor evolved in entrained by the olf-'llowing liquid refrigerant; a suction connection leading from Athe upper part of said suction trap; and a connection for supplying liquid refrigerant.

In a refrigerating system, the combination of a receiver' and an evaporator connectu ed to establish a closed circuit, said evaporator including a plurality of units connected in parallel, each unit comprising?Y a plurality of tubes connected in parallel; primary overflow distributing means arranged to equalize `he flow of liquid refrigerant to the various units; secondary over-flow dist-rilnitingl means arranged to equalize the flow to the various tubes of each unit; power circulating means for circulating liquid refrigerant through said circuit, under the control of said distributingr means; a connection for withdrawing vaporized refrigerant from said evaporator; and a connection for supplying liquid refrigerant to said circuit.

4. The combination of a variable capacity compressor; a condenser to which said compressor discharges; a plurality of evaporator' units each including an evaporator and a suction trap connected to form a closed circuit; power means corresliondinp,` to each circuit for circulatingl volatile liquid refrigerant from the suction trap through the evaporator and back to the suction trap; means for adjusting the circulatory rate of each power circulating means independently; vapor suction connections leading from the respective circuits to the suction of said compressor; and means for returning liquid refrigerant from said condenser to said circuits to compensate .for evaporation therein.

5. The combination of a varial'ile capacity compressor; a condenser to which said com-- presser discharges; a plurality of evaporatorunits each including an evaporator and a suction trap connected to form a closed circuit; power means corresponding; to each circuit for circulating volatile yliquid refrigerant from the suction trap through the evaporator and back to the suction trap; an adjustable bypass between the intake and discharge of each circulating means operable to vary the circulatory rate through 'the corresponding evaporator;v vapor suction connections leading' from the respective circuits to the suction of said compressor; and means vculatory rate in one circuit independent of that in another; a vapor suction connection from the various circuits to the compressor; y

and automatic means for delivering liquid refrigerantfrom the condenser to said circuits at rates commensurate with the evaporation of refrigerant in such circuits.

7. The combination of a two-stage variable capacity comliircssor having an inten stage passage; a condenser into which the high pressure stage of said compressor discharges; a primary refrigerant cooler; a feed device for delivering volatile liquid refrigerant from the condenser to said primary cooler; a vapor suction connection from said cooler to the interstage passage of said compressor; an evaporator circuit consistinfr of an evaporator; a suction trap and a power circulating means for circulating volatile liquid refrigerant from the trap through the evaporator and back to the trap; an automatic valve device for supplying liquid refrigerant from said primary;

cooler to said trap at a rate commensurate with the evaporation in the evaporator; a vapor suction connection from the evaporator circuit to the low pressure stage of the compressor; and means for varying the circulatory rate `in said circuit.

8. The combination of a two-stage variable capacity compressor having an interrstage passage; a condenser into which the high pressure stage of said condenser discharges; a primary refrigerant cooler; automatic means for :feeding liquid refrigerant from said condenser to said primary cooler; a vapor suction connection from said.' primary cooler to the intel-stage passage of said compressor; a plurality of indelziendent evaporator circuits 'each consisting or an evaporator, a suction trap; and power operated means for circulating volatile liquid refrigerant from the trap through the corresponding evaporator and back to the trap independent means for varying the circulatory rate of each circulating means; and a vapor suction connection from each evaporator circuit to the suction of the low pressure stage of the compressor,

9. The combination of a compressor; a condenser; a circuit including a suction trap; an evaporator mounted above said trap so as to drain to the trap; and a power actuated circulating means arranged to draw volatile liquid refrigerant from the trap anddis charge it through the evaporator and hack to the trap; a suction connection from the trap to the suction of the compressor; a stop valve controlling said connection; and a valve controlled connection for delivering hot gas from the compressor to said circuit.V

l0. The combination of a two-stage compressor; a .condenser into which said com linessor discharges; a primary cooler; means for delivering refrigerant liquefied in the condenser 'to the primary cooler; a vapor suction connection from the `primary cooler lto the interstage passage of said compressor;

an evaporator circuit consisting of a suction trap; an evaporator arranged to drain by gravity into said trap and power actuated circulating means arranged to draw liquid from the trap and discharge it through the evaporator back to the trap; means for feedliquid refrigerant from the primary cooler to the trap; a back-flow connection from the trap to the primary cooler; liquid level control means for openinff said backflow connection upon the existence of an unduly high level of refrigerant in the trap; a suction connection from the trap to the low pressure stage suction of said compressor; a stop valve controlling said suction connection; and a valve controlled. connection for delivering hot gas from the coin:- pres to said evaporator circuit.

ll. ln a refrigerating device; the combination of a circuit including a reservoir; an evaporator mounted above said reservoir so as to drain thereto, and a power actuated circulating means arranged to d 'aw volatile liquid refrigerant from the reservoir and discharge it downward through the evaporator and back to the reservoir; a suction connection for withdrawing vapor evolved in the evaporator; a stop valve controlling said connection; and a valve-controlled connection for delivering hot gas to said circuit.

l2. An evaporator comprising in combinaand to a point above tl liquid level therein;

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Suid projecting ends being. 'formed willi lateral perforzitions.

14;. An evaporator comprising in combinetion, e manifold adapted to receive liquid refrigerant; and e plurality of tubes extending downward from said manifold,tl1e upper ends of .en

id tubes projectingI through the bottoni of the manifold into the saine and to :i point above the liquid level therein, said projecting ends being formed with lateral 10 perforations graduated in size.

ln testimony whereof I have signed my nume to 'lliie' specification.

THOMAS SHPLEY.