Патент USA US2405944код для вставки
, Au, , 1946. _E. A. EDMoNDs DIRECT EXPANSION CHILLER Filed Nov‘. 20, 1945 3mm vE zimanzzis' W Patented Aug. 20,‘ 1946 2,405,944 UNITED‘ ‘STATES ‘PATENT’. oFi-ucr. _' DIRECT EXPANSION CHILLER, Eugene A. Edmonds, Louisville, Ky., assignor to Henry Vogt Machine Co. Inc., Louisville, Ky., a corporation of Kentucky Application November 20, 1943, Serial No. 5l1§148 4 Claims. (01. 62-114) . 2 _ This invention relates to a direct expansion chiller and proposes a construction in which the heat exchanging unit comprises a bundle of tubes larged scale through the left end of one of the chiller tubes and sight glass; _ _ Figure 5 is a longitudinal section on an en; generally connected serially, through which the larged scale of the right end of one of the chiller liquid to be cooled flows, and a shell surrounding the tube bundle constituting the evaporator of tubes, illustrating the packing for the scraper a refrigeration system, containing liquid refrig Figure 6 is ‘a'diagram illustrating the constant level liquid refrigerant controlled from a single drive shaft; ' _ ~ erant. ri‘his arrangement avoids the use of stu? ?oat valve; ’ ing glands which seal the ends of the individual Figure '7 is a diagrammatic view illustrating refrigerant jackets in chillers of the double pipe 10 the liquid level control of the refrigerant by in type, and which are subject to leakage of re frigerant. . dependent float valves. ' > Referring now in detail to the several ?gures, One of the objects of the invention is to pro~ the'numerals l and 2 represent direct expansion vide a chiller of the type described, in which the tubes are secured adjacent their ends in tube 15 chiller units, each comprising a tube bundle con sheets which constitute opposite ends of the chiller, the latter being provided with one or more expansible zones capable of contracting or ex panding in the direction of the length of the sisting of a plurality of spaced parallel tubes 3, surrounded by a shell ll having the cylindrical side wall 5 and the end walls 6 and ‘I, said end walls being tube sheets'through which the tubes tubes, thereby avoiding stresses, particularly in 20 3 extend, and to which they are secured in fluid. tight manner, as by welding. For the sake of the joints between the tubes and tube sheets, and eiilciency, the tubes 3 extend beyond the respec between the tube sheets and the surrounding wall tive tube sheets only far enough to be serially of the shell, which would otherwise-be produced interconnected by the transverse connections 8, through differential thermal expansion between the tubes and shell. 25 and to receive the end adjuncts which on the lefthand side of the apparatus, as shown, con~ Another object of the invention is to form the sist of the sight glass mountings 9, and on the expansible Zone as a channel with drainage means opposite side of the apparatus comprise the pack at the lowermost point so that contaminating oil ing box for the scraper shafts. from the refrigerant may collect in the channel One of the tubes 3, the ?rst in the series, is and from time to time be discharged. ' provided. with the inlet coupling ll, while the Still another object of the invention is the last tube of the series is provided with the outlet provision of a direct expansion chiller as de coupling 12. Where two units are serially inter scribed, in which the individual tubes are pro vided with the customary scrapers, driven from connected, as shown, the outlet 12 of the lower one endof the apparatus, in which the tubes 35 unit is coupled to the inlet H of the upper unit. extend beyond the tube sheet at least at the end Since the inner tube system will ordinarily re opposite the scraper drive, in a position exposed ceive a liquid to be cooled while the shell will con for inspection, each being provided with an end tain the refrigerant, there is a considerable tem sight glass through which the end of the scraper perature differential between the tubes and the shaft is visible so that breakage of a shaft can 40 wall of the shell which tends to differentially ex be readily discovered by observing the nonrotat pand or contract these members. In the absence ing condition of the end of the broken shaft of some compensating provision, this would through the sight glass. ordinarily create a strain at the joints between Other objects of the invention will appear as the tubes and tube sheet and along the joint be the following description of a preferred and prac 45 tween the tube sheet and shell. To avoid such tical embodiment thereof proceeds. ‘ strains, the invention provides the cylindrical wall In the drawing which accompanies and forms 5 with an expansion joint l3 having the form of a part of the following speci?cation and through an outwardly extending channeled ?ange of sheet out the several ?gures of which the same refer material capable of freely expanding or con ence characters have been used to. denote iden 50. tracting to compensate for differential elonga tical parts: tion between said surrounding wall and the Figure 1 is a longitudinal vertical section chiller tubes. Said expansion joint is illustrated through a chiller of the direct expansion type as being formed from pressed circumferential embodying the principles of the invention, two units being shown serially connected and in 55 members welded together and to adjacent por ' , tions of the surrounding wall 5 between which’ superposed relation; Figure 2 is an end elevation of the left end of Figure 1; . Figure 3 is an end elevation of the right end of Figure 1; -'-"Figure 4 .is a longitudinal section on an'en itintervenes. There may, of course, be one or more of these expansion joints to each unit. Only one for each unit is shown in the illustrated embodiment of the 60 invention, and to. provide for the compact posi-j 2,405,944 3 4 tioning of the units, one is shown on the left side ' journaled in a plate 43, which is pivoted eccen trically of the axis of said stub shaft at a point and the other at the right. ‘ The tube bundles are intermediately supported within the shell by a suitable plate or bracing M to the support 36 so that the sprocket M can be tilted towards or away from the driving chain members, not shown. 38 which it engages. The plate 43 is provided Each of the tubes 3 is provided in the customary . . with a threaded pin 45 extending through an manner with scrapers l 5, each comprising a shaft l6 with blades ll'supported. thereby and prefer ably inclined to the axis of said shaft, said blades ‘ 'arcuate slot 46 in the support 36 carrying a nut, by means of which the plate 43 can be ?xed in any position of adjustment. The support 33 has engaging the inner wall of the tube with a scrap 10 an arcuate slot 41, providing play for the stub ing action which removes deposits from the liquid , shaft 42. , to be cooled, agitates the liquid to bring all parts In the embodiment of the invention, as shown, in which two chiller units are arranged in super of it into contact with the wall of the tube and increases the e?iciency of the heat exchange by posed relation, the liquid level of the refrigerant in each .unit may be regulated in various ways familiar to those skilled in the art, two of which are illustrated in Figures 6 and 7. In the former, keeping the tube clean. ‘The scraper shaft is__car ried in bearings 48, and by intermediate bearings, not shown. The scraper 3 shaft adjacent the driven end is provided witha ‘lantern gland l9, slidably mounted within a cylindrical’ packing chamber formed in theend closure at. The pack ing chamber has a restricted innervend wall 2i for retaining inner packing rings 22 which sur round the shaft [6 of the scraper. Sufficient of said ‘packing rings are employed to maintain‘ the gland in a de?nite zone of the bushing I9, in which zone said chamber is tapped by a drain 23 for collecting any liquid which may leak past the inner packing rings. Since the packing may be an arrangement is shown in which a single ?oat . valve controls the level liquidrefrigerant in both units. In this form an overflow pipe 4-8 is pro vided, the upper end of which enters the upper shell at a point determining the desired liquid level in said shell, the lower end opening into the lower shell below the normal liquid level therein. Liquid refrigerant from a receiver is supplied by the pipes 49 and 5G to the upper shell, preferably above the liquid level therein, and ?lls the upper shell until it over?ows by way of the pipe 48 into from time to, time compressed to a greater or less ; ; the lower shell, ?lling it to a level determined by degree, the gland is provided with an ‘exterior so the position of the ?oat in the ?oat chamber 5!, channel 24 wider than the diameter of the drain 23, so as to remain in registry with said drain re gardless of longitudinal shift‘ in the position of the lower part of which is in communication with the liquid in the lower shell, while the upper part has a gas equalizing connection with the gas space in the upper shell. The ?oat controls the A follower 25 is bolted to the bushing, having a - ’ feed valve 52. When the warm liquid to be cooled, skirt 26 entering the packing chamber and press or load, evaporates the refrigerant in the upper ing against outer packing rings 22', which inter shell and the liquid level recedes, then the “load” vene between said follower and gland. The bolts will be shifted to the lower shell because the warm have the form of studs 21 screwed into the ?anged oil will come to the lower shell at a higher tem end wall of said packing chamber, and having . perature. This increase of load on the lower nuts which press against said follower and by shell evaporates the liquid refrigerant in the which the compression of the packing may from lower shell. The liquid level ?oat control then time to time be adjusted. functions by admitting liquid refrigerant to the The extended ends of the tubes 3 at the left upper shell until its over?ows and re?lls the lower end of the unit have a ?ange collar 28 integrally < shell to the proper refrigerant level. Since the attached thereto as by welding, and to the collar liquid to be cooled is warmer when it enters the 2. plate 29 is bolted, which contains the bearin ' upper shell 1 than when it enters the lower shell 38 for the adjacent end of the scraper shaft and 2, the rate of ebullition of the refrigerant in the has a central recess receiving the sight glass 3!, 3 upper shell will be greater than that in the lower the latter being retained bysthelbezel 32, which 50 shell, so thatthe level of liquid in the upper 'shell is removably attached, as by the stud bolts 33. would at any time be lower than the liquid level The shaft terminates in a nut 34 which thrusts in the lower shell. This means that the upper against the bearing 38, the sight glass being shell would operate at lower ef?ciency. In order slightly spaced from the nut by a spacer ring 34’. to compensate for this greater rate of ebullition Referring again to the right side of the‘ unit, in the upper shell, a by-pass pipe 53 is provided the shafts l6 extend beyond the follower 25 hav which by-passes liquid refrigerant about the ?oat ing their ends journaled in bearings 35 carried controlled valve 52. The by-pass pipe is con by an upright support 33 mounted upon the ?oor trolled by a valve 56. This valve may be adjust~ or foundation. Between the follower 25 and ed to continuously admit a relatively small flow bearing 35 the shafts [5 are provided with the 60 of refrigerant into the upper shell. The‘ amount sprockets 3'! disposed in the same vertical plane of additional liquid refrigerant thus supplied to and surrounded by a driving chain 38, the" latter the upper‘ shell may be readily controlled, for if being driven by a sprocket 35 on an extended por the valve 54 were opened too far, the result tion of one of the shafts l5, ‘and which in turn is would be an increase in level in the upper shell i the gland due to the compression of the packing. driven through the chain 30 from a motor, not 65 until the level reached the over?ow, whereupon, the level in the lower she'll would be raised‘ by‘ the shown. Since the tubes 3 are connected serially and the liquid therein flows alternately fromone over?ow‘, preventing the ,valve 52 from opening and eventually ?ooding the'apparatus. However, end to the other of the chiller unit, the chain drive is so disposed about the‘ sprockets 3‘! as to . the frequency of operation of the ?oat controlled reverse the direction of drive of the scrapers ‘in 70 valve 52 can readily be determined‘ and the valve adjacently connected tubes whereby the slight 54 be adjusted’ to prevent over?ow from‘ theup propulsive effect of the inclined scraper blades per to the lower shell, due to the continuously accelerates the ‘?ow of liquid» in each tube‘. _ added refrigerant. ' A chain tightener? is provided comprising‘ an In that form the invention shown in Figure 7, idler sprocket 41, mounted on a stub shaft? 42 75 liquid refrigerant is independently fed to both 2,405,944. 6 5 the upper and lower shell by way of the branch pipes 55 and 56 from the main liquid feed pipe 51. Independent float valves 58 and 59 control the amount of refrigerant fed to each shell, the respective ?oat chambers having their lower and upper portions connected to the lower and up per portions of the respective shells. It is to be understood that the invention is com plete in the use of a single unit, also that the ar rangement of units where a plurality are em ployed is a matter of choice, the two arrange ends of said series, a liquid refrigerant inlet com municating with said shell and a gaseous refriger ant outlet at the top of said shell. 2. In a direct expansion chiller, a shell com prising a longitudinal tubular wall and spaced tube sheets to which said wall is secured, form ing end closures of said shell, the latter being the evaporator of a refrigeration system, a plu rality of spaced tubes passing through said tube 10 sheets and secured thereto with integral sealed ments herein disclosed being merely by way of example. joints, said tubes being serially interconnected externally of said tube sheets, having a liquid inlet and outlet respectively at the anterior and posterior ends of said series, a liquid refrigerant Each chiller unit is provided with a gaseous refrigerant outlet 65 at its upper part for con 15 inlet communicating with said ‘shell and a gas ‘eous refrigerant outlet at the top of said shell, necting to the suction or low side of the refrig said tubular wall having an integral expansible eration system. Where a plurality of units are corrugation extending thereabout, concave on the combined, gaseous refrigerant outlets may dis inside of said 'wall and having a drain in its lower charge into a common stack, not shown, for multi-pressure operation. A ba?le 6| is prefer 20 portion. 3. In a direct expansion chiller, a shell com ably mounted within the vshell in the gas space prising a longitudinaI tubular wall and spaced therein, in confronting, spaced relation to the tube sheets to which said wall is secured, form outlet 60 to prevent liquid refrigerant under con ing end closures of said shell, the latter being ditions of ebullition from being drawn oil‘ in the 25 the evaporator of a refrigeration system, a plu current of evacuating gas. rality of straight tubes passing through said shell The construction of a direct expansion chiller and said tube sheets, extending therebeyond, lat with a single refrigerant chamber serving a plu eral connections serially connecting said tubes rality of tubes in which the tubes are integrally joined to the tube sheet through which they pass, ' externally of said shell, scraper shafts journaled and in which the longitudinal shell Wallis formed 80 in bearings in said tubes, terminating within said tubes at one end of said shell beyond said lat with an integral expansion joint, is an improve eral connections and extending beyond said ment both from the standpoints of simpli?cation tubes at the opposite end of said shell, driving and e?iciency, over the conventional double pipe chiller having a refrigerant jacket individual to means on the extended ends of said shafts, clo each tube, in that all packing joints for retaining 35 sures for the ends of said tubes adjacent said the refrigerant are eliminated, and leakage of driving means, each closure having means form refrigerant which is inherent in all packing joints, ing a cylindrical packing chamber through which the drive shaft passes, said packing chamber is avoided. The location of the ends of the tubes, on that having a restricted inner end of wall, a lantern side of the unit remote from the scraper drive, 40 gland through which said shaft passes, interme in an exposed position and the provision of lat diately located in said chamber, packing within eral interconnections between the tubes which said chamber on both sides of said gland, and an leave the ends of the latter unobstructed, to axially adjustable follower extending into the gether with the provision of the individual sight outer end of said chamber in compressive rela glasses forming closures for said ends, permits tion to said packing, a drain communicating lat the operative condition of the scrapers to be as erally with said chamber in the zone of said certained by mere observation so that a broken gland, the latter having an external circumfer» scraper shaft can readily be detected through ential channel wider than the opening of said the fact that the observed end is not rotating. drain whereby said channel remains in registry In the event of a broken scraper shaft, the af with said drain, regardless of longitudinal shift fected scraper mechanism may be readily re in the position of said gland due to compression moved by detaching the sprocket at the drive end, removing the plate 29 which carries the sight glass and adjacent bearing and withdrawing the entire scraper mechanism through the end of the tube thus opened. of the packing. 4. In a direct expansion chiller, a plurality of units vertically tiered, each comprising a shell including a longitudinal tubular wall and spaced tube sheets to which said wall is secured form ing end closures of said shell, the latter being the evaporator of a refrigeration system, a plurality While I have in the above described what I believe to be a preferred and practical embodi~ ment of my invention, it will be understood to of spaced tubes passing substantially horizontally those skilled in the art that the speci?c details 60 through said tube sheets and secured thereto with of construction and arrangement of parts are by integral sealed joints, said tubes of each unit being serially interconnected externally of said way of illustration and not to be construed as limiting the scope of the invention as de?ned in the appended claims. What I claim as my invention is: 1. In a direct expansion chiller, a shell com tube sheets, having a liquid inlet and outlet re 65 spectively at the anterior and posterior ends of prising a longitudinal tubular wall and spaced tube sheets to which said wall is secured, form ing end closures of said shell, the latter being the evaporator of a refrigeration system, a plurality of spaced tubes passing through said tube sheets and secured thereto with integral sealed joints, said tubes being serially interconnected exter~ nally of said tube sheets, having a liquid inlet and outlet respectively at the anterior and posterior 75 said series, a conduit for supplying liquid refrig erant to the uppermost unit, a float valve re~ sponsive to liquid level in the lowermost unit controlling primary admission of liquid refriger ant to said uppermost unit, and an over?ow con duit from a point in the uppermost unit deter mining the normal liquid refrigerant level therein, to the lower unit. EUGENE A. EDMONDS.