US2590269A - Apparatus for water ice refrigeration - Google Patents

Description

IN V EN TOR.

March 25, 1952 R. D. PIKE:

APPARATUS FOR WATER ICE REFRIGERATION 2 SHEETS-SHEET l Filed NOV. 16, 1948 Arme/vars Patented Mar. 25, 1952v APARArUs Fon WATER ICE REFRIGERATION Robert D. Pike, Greenwich, Conn.

Application November 16, 1948, Serial No. 60,263

1 Claim.

\ The present invention relates to a refrigerating apparatus and method of refrigerating particularly suitable for railroad cars wherein ice and salt or other melting point depressant are used to maintain below freezing temperatures.

It isvoften desirable to maintain the termperature in a railroad refrigerator car at or thereabout for the shipment of frozen foodstuffs, but with the usual refrigeration cars employing water ice and a melting point depressant such as common salt, for example, it has been impossible to obtain refrigeration much below 12 F. in summer weather. Although it is the practice to mix salt in the ice loaded into the refrigerator car bunkers in sufficient quantities to produce a eutectic solution having a melting point of -6 F., yet in practice this temperature cannot be -produced over a sufficient area of the ice to effectively refrigerate the air passing through the ice. In loading the ice and salt mixture the unmelted salt lies in layers and is ineffective until the salt contiguous to the ice surfaces dissolves and flows away. The resultant salt solution flows into contact with other ice surfaces where it becomes more diluted and the melting point is considerably above -Gf F. Also, with present ice bunkers, the ice and salt tend to pack and form an impervious bed so that the circulation of air into contact with the ice is choked off, thereby reducing the effective heat exchange area.

An object of the present invention is to greatly increase the refrigerating efficiency of a bed of water ice by causing the bed to remain pervious to the passage of air therethrough and to maintain a substantially eutectic solution on the surfaces of the ice forming the walls of the air pasages so that the temperature of the ice surfaces is at approximately 6 F.

Another object of the invention is to provide a method and apparatus for refrigerating a space by water ice mixed with salt or other melting point depressant in which the entire salt charge is effectively utilized to lower the melting point of the entire charge of ice.

Other objects and advantages of the invention will be apparent from the following description of a preferred form of the invention, reference being made to the accompanying drawings wherein:

Fig. 1 is a longitudinal view in section of one end of a refrigerated railway car; and

Fig. 2 4is a View in section taken on line '2 2 of Fig. 1, certain parts being shown broken away to reveal certain other parts.

(Cl. (i2- 133) In general, my invention consists in packing ice and salt, or other melting point depressant, into an ice bunker through which air from the refrigerated compartment may be circulated, preferably from bottom to top although the reverse direction of air fiow may be used, and then collecting the brine solution issuing from the bunker and discharging the brine into the ice bed at the top thereof so that the salt will be dissolved and be carried down through the bed in a nearly saturated solution. This practice enables all of the salt to be utilized more readily than otherwise, thereby increasing the efficiency of the ice as a refrigerant by promoting its melting. The brine fiowing from top to bottom of the ice bed maintains numerous open channels for the passage of air over the surfaces bathed by eutectic solution, or one nearly so.

Although my invention is susceptible of use in refrigerating apparatus for many purposes, I have shown the invention in its preferred form applied to a railroad refrigerator car. The car may be similarto that disclosed in the application of Kenneth V, Plummer and Robert D. Pike, Serial No. 21,976, filed April 19, 1948, now Patent No. 2,501,141, granted March 21, 1950, in which Dry Ice and Water ice are utilized to provide temperatures of near 0 F. in the lading compartment. By utilizing my invention in the system disclosed in said application the quantityof Dry Ice may be proportionately decreased. In the drawings I have shown the apparatus located in one end of a refrigerator car and it is to be understood that a similar apparatus is preferably located at the opposite end which, to avoid repetition, is not shown. The refrigerator car itself may be of conventional design having the standard bottom Wall ID, end wall II, side Walls l2, and roof I3, all of which may be insulated in the usual manner. Preferably, a perforated, false floor I5 is provided upon which the goods to be transported are loaded, and this floor, together with the sides and bottom of the car, form an air chamber I6 intermediate the floor I5 and the bottom wall I0. Side wall ilues, not shown, are

adjacent the end of the car which forces it into the end of the car as indicated by the arrows in Fig. 1. The fan |1 is indicated in a general `way since fans of this type are well known to the art and it may be driven either by a motor or by a belt from the car axle and neither of which are shown.

As has been pointed out above, the refrigerat- 1 ing apparatus is located at each end of the car and in each instance the apparatus comprises a water ice bunker located in a compartment formed by the end wall of the car, the side walls I2 and a vertical partition 2|. The partition 2| extends upwardly from the floor I5 and terminates short of the ceiling of the car to provide an air passageway 22 into the top portion of the car from the bunker. 23 are mounted at the opening 22 for directing air from the bunker laterally into the car. The ice is contained in a wire basket 25 which is supported by plywood wall members 26 with the open top of the basket engaging the ceiling of the car and in alignment with loading latches 2'! in the carroof. The lower portion of the walls 26 and basket 25 slope inwardly and the bottom of the basket consists of two hinged doors 28 which may be swung upwardly when the bunker is empty for access to the structure below the basket. By this arrangement, air blown into the lower portion of the bunker will be directed through the ice in the basket 25 and between the wire mesh sides of the basket; and Walls 26 but preferably mostly through the ice.

A brine tank 30 is mounted directly below the basket 25 and this tank, which has an open top, is coextensive in width with the basket and the width of the tank is such that it will receive all of the liquid discharging from the bottom of the basket. The tank 30 is preferably suspended above the bottom of the car and spaced from the side and end walls of the car and the partition 2| so that air blown from or withdrawn through the chamber I6 may freely circulate about the sides, ends and bottom of the tank. It is desirable to provide for heat exchange between the walls of the brine tank and the air and for this purpose iins 32 are attached to the outer Walls of the tank to increase the available heat exchange surface.

Baleplates 35 and 36 are mounted in the tank 30 and extend lengthwise of the latter and these plates are preferably hinged at the top as at 3'! so that they may be lowered for cleaning. The lower ends of the baflies 35 and 36 rest on vertical baille plates 39 and 40, respectively, which baille plates extend the length of the tank and are spaced from the bottom thereof. The latter bale plates suppress surging of the brine in the tank due to sudden acceleration or deceleration of the car and thereby obviate spillage of brine from the tank. These plates may be removably mounted to permit cleaning of the tank. The plates 35 and 36 are normally in the position shown in Fig.

1 and they lie within the projected perimeter of the opening in the basket 25 so that they will collect any undissolved salt coming through the basket, the purpose of which will be apparent hereinafter.

An overilow pipe 4| extends into the tank 30 adjacent the top thereof to prevent excessive ill-V ing of the tank. A clean out pipe 42 is connected to the bottom of tank 30 and extends through the bottom of thelcar so that the tank 30 may beV flushed anddrained, and a valve 43 is providedfor controlling the drainagel Preferably, louvers The brine in the tank 30 is adapted to be pumped to the top part of the bunker 20 and discharged in the form of streams over the ice and salt mixture in the basket, and for this purpose I have provided a centrifugal pump 45 attached to the bottom of the car and which is driven by a suitable belt and pulley arrangement from the axle45 of the car, the belts and pulleys being indicated generally at 47. It will be noted that pump 45 is the type which will operate when running in either direction, as the car will be drawn in either direction. The pump 45 is provided with an intake pipe 5|) which extends upwardly into the lower portion of tank 30 with the opening thereof somewhat above the bottom of the tank and within the area between bales 39 and 40. The outlet of the pump 45 discharges into a pipe 5| which is connected by a T fitting to a pipe 52 which extends to front and rear of the bunker and the opposite ends of which are connected to header pipes 53 and 54, respectively. Vertically extending pipes 55 and 55 are connected to the pipe 53 at opposite ends thereof and the upper ends thereof are connected to a distributor pipe 58 which V extends the width of the bunker and adjacent one side thereof. Two pipes similar to pipes 55 and 56 but only one, 60, of which appears in the drawings, extend upwardly from opposite ends of pipe 54 and are connected to a distributor pipe 52 which is similar to pipe 58 and located at'the opposite side of the basket. Distribution pipe 52 may be omitted, if desired, and reliance placed solely upon 58. The distributor pipes consist of pipes having relatively small outlet openings therealcng for discharging the brine over the top of the ice in the bunker in the form of streams.

To attain a temperature of approximately 0 F., the bunker 26 is filled with water ice and rock salt in the proportion of by weight of ice and 30% salt. When the ice is melted this proportion will provide a eutectic salt solution, and during operation of the system, a substantially eutectic solution will be formed on the ice surface having a melting point of 6 F. In lling the bunker approximately one half of the total ice charge is placed in the basket 25, the ice being in pieces preferably ranging from 4 to 12 inches in diameter and then approximately 25% cf the total salt charge is spread over this ice in a layer. The bunker is then filled with alternate layers of ice and salt, the ice layers each consisting of one-sixth of the total ice charge and the salt layers each consisting of 25% of the salt charge. At the point of Contact between the ice and salt a brine solution is formed which lowers the melting point of the ice to approximately -6 and this brine will trickle downwardly through the bed of ice, becoming more dilute, and thence it will drain into the tank 35. As the car moves air is drawn from the bottom'of the lading compartment and forced into the end bunkers where it passes around the bottom and sides of the brine tank. The walls of the tank, chilled by the brine, cools the air which is then forced upwardly mainly through the interstices in the bed of ice where it is further chilled and is then discharged through the opening 22 back into the lading compartment 01, as stated above, the direction of the air may be reversed. When suiiicient brine has collected to enter the pump intake it is then pumped to the distributor pipes from whence it is distributed in streams throughout the top of the ice bed. This liquid, of course, descends through the bed including the salt layers, where it becomes saturated with salt. The saturated solution then bathes the surfaces of the ice causing the latter to melt, forming a substantially eutectic solution so that the bathed ice surfaces will be at approximately -6 F. As the brine descends it will become somewhat diluted, but upon recircuface although it may be largely melted. It will f be noted that as none of the salt is lost, the brine solution will approach saturation as the ice diminishes so that the extremely low temperatures of the ice surfaces will prevail at all times during the melting of the ice charge. It will be noted that should undissolved salt drop from the bed of ice, it will collect on the baies 35 and 36 and be dissolved as the brine descends onto the baffles. tion of the entire salt charge.

By increasing the efficiency of heat exchange between the air the amount of ice necessary to be maintained in the bunkers can be greatly 1\.- duced over the usual practices. For example, in the ordinary bunkers it is necessary to maintain the bunkers at least 74 full whereas in my refrigerator car the bunkers can operate as low as one-quarter full. Thus, the car can arrive at its destination with an appreciable less charge of ice than was heretofore possible and the ice wastage at destination can thereby be materially reduced.

Thus, the bed of ice willv This arrangement assures utiliza- I For sake of brevity, I have used the term salt to include various compounds which may be utilized to lower the melting point of ice.

Although I have described but one form of r'the invention, it is to be understood that other -forms might be adopted, all falling within the directly beneath the bunker vand arranged to receive brine from the bunker; a sloping baffle at the top of the tank for collecting solids drop- "ping from the bunker; a pump and liquid distributing system for pumpingbrine from the tank and discharging the same into the upper part of the bunker; and air impelling means for forcing a circulation of air vertically through the bunker.

ROBERT D. PIKE.

REFERENCES CITED The following references are of record in the 'Sie of this patent:

Switzerland s Sept. 6, 1907

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