US2260999A - Method of circulating air in refrigerator cars - Google Patents

Description

Oct. 28, 1941. c. w. MANN 1 2,260,999

METHOD OF CIRCULATING AIR I N REFRIGERATOR CARS Filed Jan. 23, 1959 2 Sheets-Sheet l E .WMAN'N Oct. 28, 1941. 2,260,999

METHOD OF CIRCULATING AIR IN-RE-FRIGERATOR CARS c. w. MANN 2 Sheets-Sheet 2 Filed Jan. 25, 1939 gwuwwto'b E .WMAN N Patented Oct. 28, 1941 METHOD OF'CIRCULATING AIR IN REFRIG- ERATOR CARS Charles W. Mann, Pomona, Calif., assignor to Henry A. Wallace, Secretary of Agriculture of the United States of America, and his successors in oflice Application January 23, 1939, Serial No. 252,422

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) 1 Claim.

This application is made under the act of March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described and claimed, if patented, may be manufactured and used by or for the Government of the United States of America for governmental purposes Without the payment to me of any royalty there- My invention relates to methods of circulating air in refrigerator cars, particularly by controlling the direction and passage of air entering and leaving the interior spaces of the car from the outside atmosphere.

My invention is directed to a more eflicient and positive control of circulating air within refrigerator cars. It can be practiced without material change in car structure, and without the use of expensive equipment.

Under ordinary circumstances during transit there are, at present, several Ways of controlling the ingress or egress .of air from the outside atmosphere to the interior sections of the refrigerator car. These are accomplished by varying the number and location of roof hatch openings and also varying the free air passage space of said hatch openings, thereby affording multiple variations of air passage. By opening diagonally situated hatch covers at each end of the car, the air flow can be directed in a cross-wise path in the car. Except for this variation in direction, all other manipulation of the standard refrigerator car appliances control only the volume of air flow, but not direction thereof.

There are a number of objections to the effective use of standard ventilation appliances for refrigerator cars, such as, lack of definite control of the passage of air within the interior of the car after it has entered the roof hatches, and a limited practical use of such standard ventilating devices, in that their lack of definite control of air direction after its entering the car may cause damage to thelading, due to exposure of some parts of said lading to harmful high or low temperatures at certain vulnerable locations in the car.

The annexed drawings and the following description set forth in detail means of carrying out my invention, such, however, illustrating the various ways in which the principle of my inven tion may be accomplished.

Figure I is a longitudinal-sectional diagrammatic view of a standard refrigerator car with hatch covers and plugs open, bunkers empty and typical lading arrangement with a bottom bulkhead closed and arrows illustrating air direction under ventilation service.

' Figure II is a longitudinal-sectional diagrammatic view of a standard refrigerator car with hatch covers and plugs open, bunkers empty and. typical lading arrangement with bottom bulkhead closed at one end and opened at the other, and top bulkhead closed in the opposite end, and arrows illustrating air direction under ventilation service.

Figure III is a cross-sectional View of the bulkhead showing sliding partition within bulkhead at top and bottom, and. opening and closing means.

Similar numerals refer to similar par throughout the several views.

Referring to Figure I, air, as shown by arrows, entering one end of the refrigerator car at hatch frame opening I, is forced downward into bunker 2 and is entirely directed to passage through top bulkhead opening 3, by reason of the fact that bottom bulkhead opening 4 has been completely blocked by closing means 9, thereby causing the air to flow into the free air space 5 over lading I. The air in moving passes over lading I through space 5 and out of top bulkhead opening 3 due to the fact that bottom bulkhead opening 4 is completely blocked by closing means 9, and finally back to the atmosphere through hatch frame opening I at the opposite end of the car from that which it entered.

Referring to Figure II, air, as shown by arrows, enters one end of the refrigerator car at hatch frame opening I, is forced downward into bunker 2 and, there being no other passage of escape, by reason of the fact that bottom bulkhead opening 4 has been completely blocked by closing means 9, and is entirely directed to passage through top bulkhead opening 3 into the free air space 5 over lading I. The air in moving passes over and down through lading I, by reason of the fact that top bulkhead opening 3 is completely blocked by closing means I0, and out through bottom bulkhead opening 4, into bunker 2, thence up through hatch frame opening I to the atmosphere at the end of the car opposite that from which it entered.

It has long been a common practice, since the advent of the present day refrigerator car with solid insulated bulkheads I, to ship various commodities at certain seasons of the year with the hatch covers I2 held open by means of a graduating iron 23, which can be used to vary the size of the opening caused by the propped up hatch cover I2. This service is commonly recommodities, such as danger from freezing, or

danger from too high temperatures. In experimental tests on several standard refrigerator cars under actual transit conditions, wherein some Were operated under standard railroad rules and practices and others were operated by observers accompanying them, it was found that greater benefits could be derived, particularly in attempting to keep the commodities at temperatures nearer cold storage conditions by delaying outgoing end of the car, the bottom bulkhead opening 4 is left open and the top bulkhead opening 3 is closed. By this temporary alteration of the standard refrigerator car interior structure, the incoming air is forced in the top bulkhead opening 3 and over and down through the lading 1, thence out of the bottom bulkhead opening 4 and hatch frame opening I at the opposite end of the car. It can readily be observed, by those familiar with the art of ventilation, that v by its very nature the structure in Figure II offers for some time the closing of ventilators when the outside atmosphere went below the freezing temperature of the fruit. By close observance with remote thermometer equipment, it was found that when it was finally necessary to close the ventilators inthe experimental test cars, that it was necessary only because fruit at the lower extremities at the bottom bulkhead openings was nearing a critical temperature and that the remainder of the lading was far above these critical conditions and if it were possible to protect these vulnerable positions in the car, the v'entilators could have remained open and benefitted the greater bulk of the load in bringing it to a lower temperature. In later experiments with this bottom bulkhead opening closed and the hatch covers left open at temperatures far below the freezing temperature of the fruit, it was found that there was little or no dangerous effect noticed, and the cold air from the outside being forced in the top bulkhead opening, as in Figure I, mixed with the warmer air in space 5 which was heated by the lading I and passed out of the car at the opposite end, through top bulkhead opening 3 and hatch frame opening I. In this method, the air so introduced to the loading space of the car affects the lading uniformly, and no extremities of the lading are I endangered by concentration of the incoming air blast at any one point, as would otherwise be the case if the bottom bulkhead positions were left open, as in standard practice.

It can readily be observed by those familiar with the art of ventilation, that by its nature, the structure in Figure I offers a greater resistance to the air flowing through the car body than the standard method since one of the natural air passage channels has been completely eliminated. Hence, a lesser volume of air passage per unit of time and a proportionate reduction in effectiveness is obtained in either cooling down or warming up of the lading, as the case may be. Furthermore, no extremities of the lading have been exposed, since the air entering the top bulkhead opening 3 at one end of the car mixes with the air over the entire top of the lading 1 before passing out of the opposite top bulkhead opening 3 and finally to'the outside atmosphere through the hatch frame opening I, by reason of the fact that the bottom bulkhead openings 4 are closed in both ends, and no other means of air passage exists, except as described.

Another variation of my method of controlling circulating air in refrigerator cars is shown graphically in Figure II, wherein the bottom bulkhead opening 4 at the end of the car, which is receiving the incoming air, is closed and the top bulkhead opening 3 is left open. At the opposite end or a greater resistance to the air flowing through the car body than the method illustrated by Figure I, hence a lesser volume of air passage per unit of time and a proportionate reduction in effectiveness is obtained in either cooling down or warming up of the lading, as the case may be. Furthermore, no extremities of the lading have been overexposed, since air entering over the top of the lading 1 finds its way down through the lading I into the channel 6 formed by the floor rack 8, thence out of the bottom bulkhead opening 4, and finally out through the hatch frame opening I at the top of the bunker. Though the portion of the lading adjacent to the bottom bulkhead opening at the outlet end of the car may possibly be in the path of a greater volume of air than the rest of the lading, said air has been tempered by the rest of the lading prior to its contact with this portion of the lading.

A further method of ventilation causing a reverse in cycle of air passage as heretofore described and shown in Figure II is possible by closing the top bulkhead opening 3 and leaving the bottom bulkhead opening 4 open at the forward or incoming end of the refrigerator car, and opening the top bulkhead opening 3 and closing the bottom bulkhead opening 4 at the opposite or outlet end of the car.

Figure III however, shows, for example, one of many ways other than illustrated in Figures I and II, of accomplishing the method of directing and regulating the circulation of air in refrigerator cars by the opening and closing of top and bottom bulkhead openings, as hereinbefore described.

Figure III shows a means of closing top bulkhead opening 3 and bottom bulkhead opening 4 by means of sliding partitions l3 and I4 operating in a vertical path in slots l5 and I6, situated within the structure of insulated bulkhead l I. By rotation of gear wheels l1 and I8 on shafts l9 and 23, partitions I3 and I4 can be caused to be raised or lowered, as the case may be, by reason of the fact that gear wheels I! and I8 engage in gear racks 2i and 22,which are attached and integral parts of partitions l3 and I4.

Since the art of causing variations in sizes of apertures from their natural Wide open position to completely closed, is old, as are the varied mechanical means for accomplishing same, I do not restrict myself to any particular mechanical means, whether manual or automatic, inside or outside control, for accomplishing the purposes of my invention.

Although the invention has been described with considerable detail, it will, of course, be understood that it can be modified considerably to meet local conditions or requirements without departing from the spirit of my invention.

My invention is applicable particularly when fresh fruits and vegetables are stacked in refrigerator cars, so that air movement can be obtained Within and throughout the load. The manner of stacking varies, of course, with different products, because of the difierent size and shape of the packages. Nevertheless, the lading should be so arranged that the movement of the air is not unduly obstructed.

ber any heavier than air particles, the while forcing the air through an uppermost unobstructed opening in a wall of said chamber adjacent a loading compartment of the car, the air thence flowing across, downward, through and around lading in said car, and exhausting into a lowermost bulkhead opening at the end opposite that from which it initially entered the car, and thence upward through this empty ice bunker, and exhausting out of its hatch opening, the While sealing an uppermost wall of said ice bunker, thereby cooling, and removing from the loading compartment any gases present therein.

CHARLES W. MANN.

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