US2124110A - Refrigerating mechanism - Google Patents

Description

AVAILABLE CGPY P. C. HALL REFRIGERATING MECHANISM July 19, 1938.

Filed July 20, 1937 2 Sheets-Sheet l h I 11v VENTOR Ferry 6. Hall M9-fM.

A TTORNE Y5.

' P. C. HALL REFRIGERATING MECHANI SM July 19, 1938.

Filed July 20, 193'? 2 Sheets-Sheet 2 INVENTOR Perry C #422:

2 lz wzy f Patented July 19, 1 938 I v AWEIABLE Cigar aarnioaaarmo Maonmsnr Perry 0. Hail, Sidney, Ohio. asaignor to Copeland Refrigeration Corporation, Detroit, Mich a. corporation of Michigan Application July 20, 1937. Serial No. 154,643

4 Claims. (01. 62-126) This invention relates to refrigerating mechand in which like numerals refer to like parts anism and particularly to the evaporating units throughout the several different views, of such mechanism, the principal object being the Figure 1 is a more or less diagrammatic view ilprovision of a refrigerant evaporating unit prolustrating the application of the present invenviding a material amount of heat absorbing holdtion to a chilling slab of the so-called salad chiller 5 over capacity and that is simple in construction, type and illustrating the same connected into a economical to manufacture and eflicient in use. conventional refrigerating circuit;

Further objects of the invention include the Fig. 2 is an enlarged, partially broken, partially provision of a refrigerant evaporating unit includsectioned top plan view of the salad chiller illuslll ing a solid composition of novel characteristics trated in Fig. 1; capable of building up a reserve of heat absorb- Fig. 3 is a partially broken, partially sectioned ing effect whereby to enable the associated revertical sectional view of the salad chiller shown frigerating unit to operate through a relatively in Fig. 2 taken as on the line 3-3 thereof; low number of cycles during a given unit of Fig. 4 is an enlarged vertical, transverse sec-- time; the provision of a refrigerant evaporating tional view taken on the line 4-4 of Fig. 3; 15 unit including refrigerant passages imbedded or Fig. 5 is a perspective view of an evaporator otherwise so associated with a solid material as slab unit formed in accordance with the present to be capable of storing up a material amount of invention and by means of which chilling and/or heat absorbing effect during operative periods cooling devices of various types may be readily of the associated refrigerating unit; the provibuilt up; 20

sion of a novel non-aqueous substance which may Fig. 6 is a broken perspective view of an ice be substituted for the brine conventionally emcream cabinet which has been formed of units ployed in connection with refrigerating systems to of the type illustrated in Fig. 5; store up a heat absorbing effect; and the provi- Fig. 7 is an enlarged fragmentary, vertical secsion of an evaporating unit for refrigerating tional view taken on the line 1-1 of Fig. 6; 25 mechanisms including refrigerant passages and Fig. 8 is a broken perspective view of another a solid non-aqueous heat absorbing material arform of ice cream cabinet constructed in accord- I ranged in heat absorbing relation thereto and ance with the present invention. which material is relatively economical to pro- It wil be understood by those skilled in the art 3o duce, which may be applied at a minimum cost that wherever possible it is desirable to so con- 0 and which is effective and long livedin use. struct and arrange a refrigerating mechanism asv Further objects of the invention include the to reduce the number of cyclic operations of the provision of a refrigerant evaporating unit inmechanism in a given time period to a reasonablecludingaheat conducting refrigerant conduit and extent in order to save wear and tear onth a mass consisting principally of particles of metal mechanism, decrease the amount of service re- 35 suitably bonded together and to said conduit; the quired and other obvious reasons. A liquid brine provision of a refrigerant evaporator unit includsolution is conventionally employed for this puring a refrigerant conduit and a mass of metal pose although eutectic and other solutions have particles bonded together and to said conduit by been proposed and have been employed to a lim- 40 silicate of soda; and the provision of a refrigerant ited extent to increase the hold-over capacity of 40 evaporating unit including a refrigerant conduit an evaporator unit. In many instances it is imof a material having a high coemcient of heat practical to employ a brine or other fluid holdconductivity associated in direct heat exchange over means for the reason that provision must relation with respect to a metal wall and a mass be made for expansion and contraction of the of iron particles arranged in heat conducting rebrine during variations in temperature thereof 45 lationship with respect to said conduit and wall and such solutions are generally ofa more or and bonded together by silicate of soda. less corrosive type rendering their containers par- The above being among the objects of the presticularly open to leakage. "For instance, the use ent invention the same consists in certain novel of brine as a refrigerating effect hold-over me- 5 features of construction and combinations of dium for ice cream cabinet is objectionable for the parts to be hereinafter described with reference reason that it tends to corrode the ice cream contOt e a pa y drawings, and then cl e tainer positioned therein; in some constructions having the above and other objects in view. there is a liability of the brine contaminating the In the accompanying drawings which illustrate ice cream; and the insertion and removal of the suitable embodiments of the present invention .ice cream containers from the cabinet causes 55 casting copper or other metal tubes within the solid mass of metal the cost of the unit is thereby further increased. By the use of the present invention the disadvantages of brine as a holdover capacity for refrigerating effect is eliminated as well as the objectionable features of the use of a solid mass of metal for the same purpose and this is obtained by employing a mass of metal in the form of finely divided particles which as a whole may be readily formed to any shape desired and which are bonded together into heat conducting relationship with one or more associated refrigerant evaporator tubes by means of a suitable binding agent which itself serves as an added capacity for refrigerating effect.

In accordance with the present invention the particles of metal which are employed are pref erably cuttings, shavings, or the like obtained from machine tools employed for turning, planing, milling or otherwise machining metallic parts; metallic filings or the like, all of which may be purchased for the lowest of scrap metal prices. These metal particles may be of any desired metal such as brass, copper or the like but preferably from the standpoint of cost are of iron or steel. Cast iron shavings or cuttings are preferred from the standpoint of usually being of smaller size than corresponding cuttings or shavings obtained in machining other materials. These metal particles are bonded together and formed into a solid mass by the use of silicate of soda, commonly known as water glass, which also serves to provide a hold-over capacity for refrigerating effect although not as efficiently as the particles of metal themselves. In carrying out the invention broadly it is preferable to arrange the refrigerant conducting tube or tubes in their desired relation and to provide a mold about the same to give a final article of the size, shape and contour desired. The metal particles and silicate of soda are then mixed together in suit able proportions preferably to produce a relatively heavy paste-like substance which is poured, cast or otherwise acted upon to fill the mold. -Thereafter.as soon as the silicate of soda has hardened the assembly, if and when required, may be removed from the mold whereupon it is ready for application.

accordance with afurther phase of the present invention to construct at least a portion of the mold from sheet metal and particularly that side thereof which is to be exposed to the medium from which it is desired to extract heat and to solder or otherwise'secure the refrigerant conducting tubes in direct metallic heat conducting relationship with respect to such wall. Such wall In most cases it will be found to advantage in y or mold thereby also serves as a wall-of the finlesser extent and yet permit the advantages of the present invention to be obtained. It has been found,ho\vever, that a.satisfactory mixtureof these two materials consists of fifteen pounds of iron cuttings or shavings to approximately one gallon 5 of silicate of soda, it being understood that foreign or other substances may be present to some extent. These proportions provide a heavy paste-like composition which will set in a reasonable time into a very hard composition particularly desirable for the use intended. The water content of water glass varies considerably in commercial practice so that the amount of water glass mixed with the metal particles may have to be varied from that stated to get a sufficiently heavy paste to render it properly workable. Where iron particles are used, however, and the mixture has fully set and dried out, the resulting composition will consist of approximately three to five parts of iron to one part of silicate of soda, by weight, and preferably about four parts of iron to one of silicate of soda.

One use to which the present invention is particularly applicable is so-called chilling trays or slabs", a common use for which is found in restaurants and the like for the purpose of maintaining exposed food stuffs, such as salads, in suitably chilled condition. They are also found useful where it is desired to bring a material in temporary contact therewith for the purpose of chilling it and such use is found in connection with the sealing of wax paper wrapped around food stuffs such as bread, or the like. The application of the present invention to a chilling slab of the salad type is illustrated in Figs. 1 to 4, inclusive.

Referring now to Fig. 1 a salad chiller is indicated generally at In and as included in a refrigerating circuit including a compressor I2 driven by a motor l4 and delivering compressed gaseous refrigerant to a condenser IS in which it is cooled and liquefied and delivered to a-receiver it from which it flows through an expansion valve indicated diagrammatically at 2|! to the chiller I0 and from which it is returned to the suction side of the compressor l2. As illustrated in Figs. 2, 3 and 4 the salad chiller It comprises an inverted pan-like metal part 22 having a continuous marginal side flange 24 of substantially equal depth throughout. Particularly where the device is to be employed as a salad chiller as assumed in the presentcase it may be preferable to provide one or more of the marginal edge portions of the top surface of the member 22 with anupstanding rib such as 26 pressed upwardly therein, this being 55 particularly provided in a salad chiller for preventing the plates of salad from being pushed beyond the limit of the slab. -'I'he inverted panlike member 22 may be formed of any suitable material capable of readily transmitting heat therethrough and preferably of some metal having a relatively high coefficient of heat conductivity. Copper and stainless steel are found to be particularly desirable as such material.

' To the under-surface of the horizontal wall of 05 the panlike member 22 is soldered or' otherwise intimately secured-preferably indirect metallic heat conducting relation with respect thereto, a refrigerant evaporator tube or conduit 28. As indicated the tube 28 is preferably so formed as to provide a plurality of turns or loopsso as to equally distribute the heat absorbing effects thereof equallyover the entire horizontal wall of the member 22. Where it is desired to provide a thermostatic control for the refrigerating unit 76 controlled by the temperature of the slab l0. one end of the tubing 28 or one loop thereof, preferably at the discharge end of the tubing 28 or near the discharge end thereof, may be extended beyond the limits of the pan-like member 22 as at 30 and be provided with a receptacle such as 32 soldered or otherwise secured in direct metallic contact therewith for the purpose of receiving the usual thermostatic control bulb or feeler leg (not shown). The end portions of the tubing 28 may be led out from the side, back or bottom of the device in any desired relation to best suit the conditions of the installation met with in practice.

As illustrated .ln Figs. 2, 3 and 4 the bulk of the tubing 28 which constitutes that portion thereof which is soldered or otherwise secured in direct metallic contact to the under-face of the horizontal wall of the member 22 is imbedded in a layer 34 of a solid composition formed in accordance with the present invention. In other words the layer 34 comprises a mixture of metallic particles and silicate of soda in hardened form the proportions of which are preferably those already stated. It will be understood that this layer 34 is solid, of hard character, and is non-aqueous. The composition 34 is sealed within the inverted pan-like member 22 by means of a layer 36 of suitable plastic material of any suitable type commonly employed for sealing purposes, such as pitch or the like. The layer 36 is preferably of sufficient thickness as to positively prevent the passage of moisture therethrough to the layer 33 and it is marginally sealed to the marginal flanges 24 of the member 22 so as to prevent the possibility of moisture finding its way to the layer 34 at such point. The layers 34 and 86 are preferably of such thickness in the construction shown as to stop short of the lower edge of the side flanges 25 so as to leave the projecting portions of. such flanges to forrna pocket for reception of at least the upper edges of a layer 38 of suitable heat insulating material which may be of a cork composition or any other suitable heat insulating composition commonly offered on the open market under various trade names. The layer of heat insulating material is preferably adhered in position by the plastic layer 36.

In manufacturing the chilling slab shown in Figs. 1 to 4, inclusive, the pan-like member 22 is first formed as by a pressing, rolling, or other suitable operation, the tubing 28 is then soldered or otherwise suitably secured in direct metallic contact to its inner face. The member 22 with the tubing 28 secured therein is placed in inverted position, that is with its open side facing upwardly, and a mixture of iron or other metal particles and liquid silicate of soda, preferably in the proportions previously stated and forming a preferably heavy paste, is poured into the memher 22 and is worked into an even layer therein as by means of a trowel or the like so as to completely fill the lower portion thereof and intimately surround all of the tubing 28.

This assembly is then allowed to stand for a.

sufiicient length of time to permit the silicate of soda to completely harden and dry out, thereby producing a composition of extreme hardness and predominantly composed of metallic particles. After the mixture of silicate of soda and metal particles has completely set and dried the layer 36 of plastic or the like is then applied while the assembly is still in the inverted position. Preferably the plastic 36 is applied in hot condition so as to insure an intimate bond between it and the layer 34 as well as the inner edge'portions of the insulation 38 and the opposed wall of the flange 24 thereby insuring a complete and water-proof seal along this area. The assembly is then completed and may then be turned over to its normal position indicated. It will be understood that in practice such an assembly is usually set into a complementary opening formed in the upper face of the counter or the like and that when operating a relatively heavy layer of frost will form over the top surface thereof and the articles to be chilled, namely salads or the like, are seated directly upon the frosted surface.

In the past it has been the common practice to form salad chillers of the type described simply by employing an inverted pan-like member such as the member 22 with the coils of tubing 28 soldered thereto and without any material whatever associated therewith for the purpose of providing a hold-over capacity for the refrigerating effect. Consequently the associated refrigerating mechanism was required to operate at intervals of very few minutes to maintain the chiller at the desired low temperature. Furthermore the lower surface thereof being more or less open to direct circulation of air'in many cases fostered the formation of frost upon the lower surfaces with consequent dripping thereof on to objects positioned therebelow. It has been found that by the modification of such salad chillers in accordance with the'present inveni ion and as above described the -cyclic.periods of the refrigerating mechanism may be materially lengthened, in fact several fold, with all the attendant advantages. The resulting structure is solid and rigid and, accordingly, it does not require excessive care in its-support, its character is such as to require no service, it is immune to the effects of moisture, and is such as to apply its heat absorbing effects only in the desired direction. Inasmuch as the metallic particles which are employed are preferably machine cuttings, and the like which may be bought at the lowest scrap prices as previously explained, the

cost of providing this construction as compared to conventional constructions is only slightly/ more and yet a materially greater advantage is trated in Fig. 5 in which a generally rectangular slab is shown as comprising a hollow sheet metal container 44 within which is arranged tubing 46- preferablyin the form of a plurality of turns, soldered or otherwise intimately bonded to one of the side walls of the container 44. That portion of the internal volume of the container 44 not occupied by the tubing 46 is filled with a material iii 48 which may be identical to the material 34. disclosed in connection with Figs. 1 to 4, inclusive. {The sheet metal container I4 is preferably entirely imperforate and completely sealed at all points against the admission of moisture therethrough to the material 40. Where a slab such as that shown in Fig. 5 is to be employed as a chilling plate, as one wall of a chamber to be cooled, or in a similar manner, it will generally be found preferable to cover that face thereof which is not to serve as an active heat absorbing surface with a layer of heat insulating material such as the layer 50, thereby preventing the absorption of a material amount of heat through such face.

In Figs. 6 and 7 an ice cream cabinet is illus-- trated primarily formed by assembling a plurality of units of the type shown in Fig. 5. The ice cream cabinet shown in Fig. 6 comprises front and back walls and 62 respectively, opposite end walls 64 and a central wall 66 separating the interior of the cabinet into two separate chambers. The end wall 6| and intermediate wall 68 are each formed from a single unit such as illustrated in Fig. 5 except that in such case the ends of the tubing 46 are brought directly out from an end edge of the unit. The front wall 60 and rear wall 62 are each formed from a pair of units such as illustrated in Fig. 5 and it will be noted that these units overlap the end edges of the units forming the end and intermediate walls. The ends of the tubing for the front wall section are preferably extended along the outer faces of the and sections as illustrated at 68 in Fig. 6.

The metal coverings of adjacent sections are preferably soldered or otherwise secured and. sealed together along their lines of junction, and a suitable bottom wall isprovided and likewise soldered or otherwise suitably sealed and secured to the side and end wall sections so as to provide a fluid tight structure. The top wall 10 preferably comprises a thick slab of heat insulating material 12 enclosed in a metal sheathing I4. The top wall Hi centrally over each of the chambers is provided .with a circular opening 16 in each of which is received an insulated plug closure 18 in accordance with conventional practice. The outer faces of the outer sections forming the side and end walls of the cabinet shown in Fig. 6 are covered by a relativelythick layer of insulation 80 equivalent to the insulation 50 illustrated in Fig. 5. Although the insulation layer 80 may be applied in any suitable manner it is preferably applied by the use of a layer of .mastic 82 adhered to the outer face of the corresponding evaporator unit and to the inner face of the cooperating layer of insulation 80. Particularly where the exterior surface of the cabinet is to be exposed'the outer face of the insulation material is preferably provided with a metallic covering 84 suitably secured thereto and which may be finished in any desirableor suitable manner.

The ends of the tubing 46 in each of the units including the extended end portion 68 are preferably all extended through the rear face of the cabinet as indicated in Fig. 6 where the inlet ends thereof may be connected with singly or in multiple-to any suitable type of refrigerant supply controlling device and which may be either of refrigerated containers such for instance as a single chamber ice cream cabinet as illustrated in Fig. 8, it is not necessary to employ a plurality of individual sections such as illustrated in Fig. 5 and as explained in connection with Figs. 6 and 7 to form the same, but it may be formed as an integral-structure such as illustrated in Fig. 8. Referring to Fig. 8 a cabinet is shown including side and end walls and a bottom wall. The side and end walls in Fig. 8 are of the same general of having separate tubing in each of the side and end walls of the device a single length of tubing continuously bent around the inner sheathing is preferably employed as illustrated. This construction is suitable for smaller and more easily handled units, whereas if a refrigerating unit is of a large size it is usually preferable to construct it of section such as illustrated in Fig. 5, transported in sections to the place of delivery and there set up and secured together into the desired structure, previously explained. Where a construction as illustrated in Fig. 8 is to be employed as an ice cream cabinet or the like it will, of course, usually be considered necessary to provide its exterior surface with a suitable covering 98 of suitable heat insulating material and a top wall Hill of heat insulating material is provided with the usual central aperture closed by an insulated closure plug such as I02.

It will be understood that the illustrations of the chilling slab and of the ice cream cabinet in the accompanying drawings serve primarily as illustrations of the wide uses to which the present invention may be applied and that wherever applied the evaporator unit provides a construction free of any liquid hold-over agent for the refrigerating effect while still providing such holdover capacity for the'refrigerating effect in a rigid, solid non-leakable structure efllcient in use and relatively economical to produce.

Formal changes may be made in the specific embodiment of the invention described without departing from the spirit or substance of the broad invention, the scope of which is commene surate with the appended claims.

What I claim is:

1. A refrigerant evaporator unit comprising an inverted pan-like member formed from sheet metal, a refrigerant conduit'secured in direct metallic heat conducting relation with respect to the lower face of said pan-like member, a layer of material substantially enclosing said refrigerant conduit and underlying the lower face of said'member, said layer of material terminating above the lower edges of the side walls of said pan-like member, a sealing material sealing the lower face of the first mentioned material and marginally sealed to the inner side walls of said pan-like member. and a layer of heat insulating material disposed below said sealing material and overlapped at least in part by the side walls 0 said pan-like member.

2. A chilling slab for salads and the like comprising an inverted sheet metal pan-like member of relatively great length as compared to its width, a plurality of loops of'metallic refrigerant conduit secured in direct heat conducting relationship with respect to the lower face of said pan-like member, a layer of rigid material providing a heat absorbing capacity for said conduit substantially enclosing said conduit and covering the lower face of said pan-like member, means sealing the lower face of said layer against the penetration of moisture thereinto, and further means insulating the lower face of said material against the transfer of heat thereto.

3. In the manufacture of a refrigerant evaporator unit, the steps of forming a sheet metal pan-like structure, securing a refrigerant conduit in direct metallic contact with the inner surface of the bottom wall of said pan-like member, inverting said structure, applying a mass of finely divided metallic particles and a liquid binder in said pan and working it into a layer of substantially equal thickness over the bottom surface thereof, and then allowing saidbinder to harden.

4. A chilling slab for salads and the like comprising an inverted sheet metal pan-like member of relatively great length as compared to its width, a plurality of loops of metallic refrigerant conduit secured in direct heat conducting relationship with respect to the lower face of said pan-like member, a layer of rigid material surrounding said loops and covering the lower face of said pan-like member including a mixture of metal particles bonded together by sodium silicate, means sealing the lower face of said layer against the penetration of moisture thereinto, and further means insulating the lower face of said material against the transfer of heat there- PERRY C. HALL.

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