US1744468A - Apparatus and method for cooling cargo space in ships - Google Patents

Description

Jan. 21, 1930. w. L. GREEN. JR 1,744,468

APPARATUS AND METHOD FOR COOLING CARGO SPACE IN SHIPS Filed March 25. 1926 2 Sheets-Sheet 1 Q If E k g V) v a k N N 3 QQ x w Jan. 21, 1930. w. L. GREEN. JR 3 9 APPARATUS AND METHOD FOR COOLING CARGO SPACE IN SHIPS Filed March 25. 1926 v 2 Sheets-Sheet 2 glwue/ntom chines Patented Jan. 21, 1930 UNITED STATES PATENT OFFICE WALTER LAWRENCE GREEN, JR., OF HOLLIS, NEW YORK, ASSIGNOR TO LUGKENBACH STEAMSHIP COMPANY, ENCORPORATED, OF NEW YORK, N. Y., A. CORPORATION OF DELAWARE APPARATUS AND METHOD FOR COOLING CARGO SPACE IN SHIPS Application filed March 23, 1926. Serial No. 96,774.

The object of my invention is to provide simple, inexpensive and efficient method and apparatus by means of which cargo space on ships may be maintained at a uniform moderate temperature while the ship is in warm latitudes. My invention is particularly applicable to and is of great commercial value in the water 'ransportation of those items of cargo, such as lard substitutes, cocoa but- 10 ter, etc, which require for their preservation the maintenance of a moderate temperature say from 60 to 80 F. While my method may also be applied to the production of tem- U peratures lower than those above named, it

is not primarily adapted to the production of extremely low temperatures in the cargo space.

Heretofore it has been the practice of cooling cargo space to provide, either a simple ventilation of the space by the admission and circulation of fresh atmospheric air therein, or by insulation and refrigeration of the cargo space.

The first of these methods suffers from the 25 disadvantage that the temperature of the cargo space is variable and is dependent upon the temperature of the outside atmosphere.

The prior methods of refrigeration commonly in use suffer, when applied to the creation of the moderate temperatures at which my invention aims, from the objections that they require an insulation of the cargo space and the presence in the cargo space of cooling coils, both of which features are objection- 35 able as lessening the carrying capacity of the space. Thepresenceofcoolingcoilsalsotends to introduce moisture into the cargo space and this often has a deleterious effect upon certain types of cargo. Also the danger of leakage or disruption of the coils resulting in injury to the cargo is ever present in these systems. Further, they usually require the consumption of valuable cargo or engine room space by ice or the ice-making maand their appurtenances, and often require additional crew in their inspection and mangagement. Further these methods, depending as they do entirely upon artificial cooling and circulation, require the well nigh constant operation of the ice-making machines and other apparatus, with a consequent high cost of operation.

My invention comprises a simple, economical and efficient method, embodying for the purposes named, the advantages of the previous methods and in addition other advantages hereinafter to be pointed out.

In general my invention takes the fullest advantage of the conditions and apparatus normally existent upon a steamship, and hence requires a minimum of additional apparatus and expense both of installation and operation. My method is based in part upon the fact that the lower and more submerged portions of the ship are normally cooler by a number of degrees. than the outside atmosphere when the ship is in warm latitudes, and is also cooler than less submerged or upper port-ions of the ship, such cooler condition being the normal result of the submerged condition of such portions. For instance, the shaft alley of a steamship usually constitutes the coolest portion of the after end of such ship, the temperature therein, even in warm latitudes, rarely rises higher than from 75 to 80 F. The temperature of the coolest holds in the same section of the ship is normally from 5 to higher than the shaft alley, and the outside air may often be to above that in the shaft alley.

Generally speaking, my method in its simplest form comprises the passage of fresh air into a deeply submerged portion of the ship such as the shaft alley, thereby reducing the temperature of the air below that in the cargo spaces and then passing this cooler air upward to and through the cargo spaces and back to atmosphere. In the more complete form shown in the attached drawings and hereafter to be particularly described, it comprises, in addition to the normal cooling of the air by its passage through the shaft alley or other submerged portion of the ship, the further cooling and drying of the air by apparatus located within such submerged portion of the ship, and the passage of such additionally cooled and dried air into and through the cargo space.

Referring now to the accompanying drawings wherein I have illustrated the apparatus and arrangement of parts used in employing my method as the same is actually installed upon a steamship now in commercial service between the east and west coasts of the United States:

Figure 1 is a profile of a portion of the after end of the steamship showing the lower hold to be cooled, the propeller shaft alley with the means of admission and circulation of air therein, together with apparatus for further cooling, drying and conducting such air to the cargo space.

Figure 2 is a plan view of the same taken along the line marked Top of shaft alley in Figure 1.

As shown in the drawings the after end of the steamship contains a submerged shaft alley 1, above which is the lower hold 2, separated therefrom by a water-tight partition 3. Passing from above the shelter deck through the ship is a ventilator 4, adapted to admit fresh atmospheric air into the shaft alley 1. At the after end of the lower hold 2 is an air suction duct 5 controlled by a suction fan 6 for withdrawing air from the lower hold. In the shaft alley and distant from the entrance of the ventilator 4 is a motor-driven fan 7 adapted to draw fresh air admitted by the ventilator through the shaft alley and into an enclosed air chamber 8. The enclosed air chamber 8 is suspended from the partition 3 forming the top of the shaft alley and is in communication with the air in the shaft alley through a single opening at its forward end. The after end of the chamber 8 communicates with the cargo space 2 through an opening in the partition controlled by a valve or gate 9. The valve 9 is normally opened, but when closed makes the lower hold 2 water-tight with respect to the shaft alley 1. The valve 9 is provided with an extension rod 12 passing through the shaft alley and into the engine room which permits the valve to be operated from without the shaft alley 1. Vithin the hold 2 and communicating with the opening in the partition 3 is an air duct 13 provided with holes 14 for the distribution of air through the hold 2. The holes 14 may be provided with means not shown) for closing one or more of them. The chamber 8 contains a cooling box provided with coils through which cold brine may be circulated from the brine cooler 11 of the refrigerating apparatus. The refrigerating machinery by means of which cold brine is supplied to the cold box 10 may be of any desired type and is preferably located in the shaft alley. In the drawings it is shown. diagrammatically, as comprises a steam-driven ammonia compressor 18, suitable ammonia condensing coils 15, an ammonia receiver 16 and abrine cooler 11.

The operation, in the practice of my inven- {ion of the parts above described is as folows:

Fresh air from without the ship enters the shaft alley by ventilator 4 and is drawn therethrough by the fan 7 By reason of the submerged position of the shaft alley the temperature of this air is reduced to a point lower than the normal temperature in the hold 2 and may be then passed through the enclosed chamber 8, the cold box 10, valve 9 and duct 13 into the lower portion of the hold 2, whence it is drawn through and over the 1 cargo to be cooled and returned to atmosphere through the air suction duct 5.

Unless the climate be extremely warm the cooling, effected by the passage of the air through the shaft alley and upward into the hold 2, may itself be sui'licient to maintain the temperature of the hold 2 at a suitable moderate temperature, but if conditions require further cooling, or if it be essential to proper care of the cargo that the air be dried before admission into the hold 2, the refrigerating machinery shown may be operated so that the coils in the cold box are charged with cold brine. In this event, the air in its passage through the shaft 8, will pass over and around the coils and will be further cooled thereby. The moisture in the air will be transformed to water of condensation on the brine coils and the air thus additionally cooled and dried, will pass through the valve 9 and duct 13 into the lower hold and be drawn therethrough as previously described.

If it be desired to confine the cooling to a specific part of the hold 2, a portable curtain such as indicated at 17 may be used to separate the portion to be cooled from other portions of the hold and the holes 14 on one side of the duct 13 may be closed, and the cooling air directed in one direction only.

The provisions made by me and illustrated in the attached drawings have the following peculiar advantages among others:

1. Full advantage is taken of the normally lower temperature of the shaft alley to precool the fresh air admitted therein.

2. There is no re-circulation of the air, but a continual passage of fresh atmospheric air through the shaft alley and hold.

3. The refrigerating machinery is located in a portion of the ship not suitable for other uses, and may there conveniently be operated and attended without the employment of ad ditional crew, such attention as may be required being readily given it on regular inspections and oilings of the shaft bearings located in the shaft alley.

4. The location of the cooling, coils in the shaft alley and below the hold 2 has the dual advantage of conserving cargo space and of removing the moisture from the cooling air at a point without and below the hold to be cooled.

5. The absence of insulation of the hold 2 conserves cargo space, and

6. The arrangement as a whole, making as it does, the fullest use of the-normal equipment on the ship reduces the costs of installation and operation to a minimum.

The foregoing detailed description has been given for clearness of understanding and no undue limitations should be deduced therefrom, but the appended claims should be construed as broadly as permissible in view of the prior art.

Having fully described my invention what I claim is 1. Apparatus for cooling cargo space on a ship provided with a propeller shaft alley and a cargo space, comprising means for admitting fresh air to the shaft alley, an enclosed air duct located in said shaft alley means for drawing said air through the shaft alley and into the said enclosed duct, means for cooling and drying said air Within said air duct, a normally open water-tight valve connecting said enclosed duct with the cargo space to be cooled and means operable from a point Without said shaft alley for controlling said valve.

2. The method of cooling cargo space on a ship provided with a propeller shaft alley and a cargo space, comprising the admission of fresh air to the shaft alley, cooling said air by drawing it through said shaft alley passing said air into an enclosed air duct, further cooling and drying the air therein, passing said air through the cargo space to be cooled and thence returning it to atmosphere.

3. Apparatus for cooling cargo space on a ship provided with a propeller shaft alley and a cargo space, comprising means for admitting fresh air to the shaft alley, an enclosed compartment located in said shaft alley, means for passing air through the shaft alley and into said compartment, means for cooling and drying said air in said compartment and means for passing said air through the cargo space and returning it to atmos- Jhere.

l XVALTER LAWRENCE GREEN, JR.

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