US2337789A - Cooling device - Google Patents

Description

Dec. 28, 1943. R. T. WHITNEY COOLING DEYICE Filed June 7, 1941 ATTORNEY WT H w mm.v 2+6 2 w a 0 a. 2

7, m 3 2 0 a a4 a a Patented Dec. 28, 1943 COOLING DEVICE Ralph T. Whitney, Irwin, Pa.,

assignor to The Westinghouse Air Brake Company, Wilmerding, Pa, a corporation of Pennsylvania Application June 7, 1941, Serial No. 397,047

12 Claims.

This invention relates to cooling systems for compressed air and more particularly to means for removing moisture from the compressed air used in fluid pressure brake systems.

The compressed air used in air brake systems for controlling the brake apparatus on cars of a train is usually drawn from a main or storage reservoir on the locomotive which is charged by the operation of an air compressor.

The compressing of air causes an increase in the temperature of the air. Subsequent cooling then usually results in precipitation of a portion of the moisture in the compressed air. It is desirable that all precipitation occur before the air is passed on to the brake system since moisture in the brake system is liable to cause corrosion and formation of iron oxide or rust scales, which is liable to interfere with or prevent the operation of devices in the system. Further, in cold weather the freezing of moisture is liable to impede or stop the operation of the devices or cause closing or restricting of air flow passages or cavities with possible complete failure of a device.

To prevent precipitation of moisture in the brake devices of a brake system it is therefore necessary after compressing it to cool the air to substantially atmospheric temperature before it is supplied to the brake system. The moisture content will therefore be reduced to saturation and since there will be no further cooling in the brake system there should be no precipitation of moisture therein.

In Patent 2,209,097 issued to V. Villetteon July 23, 1940, there is disclosed an air cooling device for accomplishing this end. This device comprises a plurality of heat radiating pipes which are connected in series between the air compressor and storage reservoir. As compressed air passes through these pipes from the compressor to the storage reservoir it is adapted to give up its heat caused by compression and to enter the reservoir at substantially atmospheric temperature. The cooling of the air as it passes through the cooling pipes will cause a precipitation of a portion of the moisture originally in the air so that by the time it enters the storage reservoir at substantially atmospheric temperature all moisture above the saturation point will have been expelled. As this air is then supplied to the brake system there will be noprecipitation therein, as will be apparent.

As pointed out in the above referred to patent, the capacity of the compressed air cooling evice must be greater for use in hot weather than in cold weather. For instance, a capacity adequate for cold weather would be inadequate for hot weather since it would result in the passing of air to the storage reservoir, at a temperature above that of the atmosphere; so that further cooling would occur in the storage reservoir or even in the brake system, if the air supplied thereto was still above atmospheric temperature. On the other hand, if the cooling device were adequate for hot weather an excessive degree of cooling might result in cold weather with the result that freezing of precipitate might occur in the cooling device, which would be intolerable.

To meet these different conditions the cooling device disclosed in the above referred to patent was therefore provided with a maximum capacity suited to a certain range of temperatures in hot weather. Means including a manually operable cock was provided to open and close a communication between the reservoir and one of the intermediate pipes in the cooling device. This cock was adapted to be closed in hot weather so that the compressed air would have to travel through all of the pipes so as to obtain the required degree of cooling. In cold weather however this cock was adapted to be opened so as to reduce the length of the path which the compressed air had to travel to reach the storage reservoir, thereby, in effect, reducing the capacity of the radiator so as to avoid excessive cooling under the cold weather condition.

A cooling device or radiator of the above type is normally mounted near the front of a locomotive in order to obtain a maximum degree of air circulation for cooling purposes. In order to adjust the radiator to the different weather conditions it is therefore necessary for an engineer to get down out of the locomotive and go to the front thereof. This of course is not particularly objectionable for seasonal weather changes. However, on a certain railroad a train in traveling between two terminals is at one time in an extremely warm climate and a few hours later is in a relatively cold climate. During such a trip it is therefore necessary for the engineer to get out of the locomotive to adjust the cock on the cooling device to suit the particular climate. This of course is objectionable.

Moreover, the cooling device disclosed in the above patent is adapted to provide only two different degrees of cooling and hence requires only one cock. For greatest-efficiency it is apparent that more than two different degrees of cooling is desirable which however would require the addition of one or more cooks for operation by the engineer. This also is objectionable from the engineers standpoint and therefore very likely the cooks would not be adjusted as they should be.

One object of the invention is the provision of an improved cooling device embodying tempera ture responsive means which is operative automatically and with no attention from the engineer to adjust the cooling device to suit ambient temperature conditions.

According to this object the manually operative cock employed in the cooling device disclosed in the above referred to patent is dispensed with and in its place there is provided a valve which is automatically responsive to temperature, so as to open the valve when the temperature is below a certain degree and close the valve when above said degree. Assuming that the temperature controlling this automatic valve is that of the atmosphere it will be apparent that this device will ensure obtaining the intended result at the proper temperature and without any attention or efiort on the part of the engineer, and with no delay in a train schedule resulting from an engineer having to leave the locomotive for manually adjusting a cock.

By the use of this improved temperature controlled valve most efficient cooling of air for all temperatures may be readily obtainedsince any desired number of the valves adjusted to operate at different temperatures may be employed to provide any desired number of different lengths of cooling paths through which the compressed air must flow for dissipating heat. Such efficiency is not practicable with the structure dis-- closed in the above patent, as pointed out'above.

If desired, this improved valve may be arranged to be controlled by the temperature of the compressed air flowing through a certain part of the cooling device. When thus controlled the temperature of the air at that certain part of the cooling device will cause closure of the automatic valve when in excess of a certain degree and opening of the valve when lower than said certain degree and thereby produce substantially the same result as obtained when controlled by the temperature of the atmosphere.

In the above referred topatent, water which is precipitated as the compressed air flows through the parallel arranged cooling pipes has to flow from one pipe ta another and finally into a drain device whichmay operate automatically at intervals to dissipate collectedmoisture to the atmosphere. Since these pipes are horizontal moisture will collect along the bottom of the pipes and may not promptly flow to the drain device. Moreover, in case the pipes are not exactly horizontal, due to installation or due to a locomotive being on a banked curve, the precipitated moisture is liable tocollect in pockets. Air flowing through the pipes would then have to flow through these pockets of water with the attendant possibility of the air picking up some of this already precipitated water and carrying it on to the outlet and thence. to the storage reservoir. Moreover water collections in these pockets might freeze and burst the cooling device in cold weather particularly when the locomotive is idle.

It will therefore be apparent that it is desirable to completely remove the water from a cooling device and. out of the path of air flow as quickly as possible, and another object of the invention is the provision of an improved-cooling device for accomplishing this end.

. Other objects and advantages will be apparent from the following more detailed description of the invention.

In the accompanying drawing; Fig. 1 is a diagrammatic outline View of a fluid pressure cooling system embodying one form of the invention; Fig. 2 is a diagrammatic view, partly in section and partly in outline of a modification of the invention shown in Fig. 1; and Fig. 3 is a diagrammatic outline view of another form of the invention.

In the drawing, the reference numeral l indicates an air compressor which may be of any desired type adapted to draw air from the atmosphere and to compress same into a storage or main reservoir 2, such as used on railway locomotives, and from which fluid under pressure is adapted to be drawn for charging and controlling the brake system of trains.

The reference numeral 3 in Fig, 1 and 3A in Fig. 3 indicate heat radiating devices through which air delivered by the compressor I must flow in traveling to the reservoir 2 for the purpose of becoming cooled and precipitating moisture so that the air obtained in said reservoir will be substantially at atmospheric temperature and with a moisture content not exceeding saturation.

The heat radiating device 3 may be of any desired structure, but for illustrative purposes may comprise any desired number of parallel arranged heat radiating pipes Q to 8 inclusive. One end of pipe 4 is connected to the compressor l and one end of pipe 8 is connected to a vertically extending pipe l3 connected at its upper end to the reservoir 2. The other ends of the pipes 4 and 8 are connected by bends 9 and ID to the adjacent ends of pipes 5 and 1 respectively and the opposite ends of the latter are connected by bends H and I2 to the opposite ends of pipe 6.

It will be apparent that the several pipes 4 to 8 inclusive are connected in series with each other and thereby provide a relatively long path for air travel from the compressor I to the reservoir 2. All of these pipes are therefore adapted capacity or heat indicating surface of said several pipes will insure that the temperature of the air supplied to the reservoir pipe l3 will be substantially equal to that of the atmosphere, for all atmospheric temperatures above a certain low degree.

For atmospheric temperatures below the degree just mentioned the several pipes 4 to 8 would be liable to causeexcessive cooling of the air passing to the reservoir 2. To avoid this a pipe M containing a thermostatic valve I5 is connected between a chosen bend, such as l2, and pipe l3. The thermostatic valve l5 may be controlled by atmospheric temperature, as shown in Fig. l, and be so adjusted, that when the atmospheric temperature is higher than the degree above mentioned the valve IE will close communication through pipe 14 so that all of the pipes to 8 will be efiective as above described. When the atmospheric temperature is at a lower degree however the valve I5 is adapted to open communication through pipe M so thatthe air may flow directly from pipe 6 to pipe l3, i. e., without passing through the pipes 1 and 8. Thus when the atmospheric temperature is below the degree above mentioned a fewer number of pipes and thus only a chosen portion of the heat radiating surface of the cooling device will be connected in direct path of air flow to the reservoir 2 so that the temperature of the air in the cooling device will not become so reduced as to permit freezing of precipitate in the path of air flow. 7

As air is cooled upon passing through the cooling device 3 :a portion of the moisture originally present will be precipitated and tend to fall to the bottom of the pipes along which it will drain or be propelled by the fluid stream to the reservoir pipe l3. When such moisture reaches the pipe it? however it will drop by gravity into an automatic drain valve device l8 which is secured to the lower end of said pipe. The device 58 is preferably of the general type which will periodically operate to discharge collected water therefrom so as to maintain the cooling device substantially free of water. The device i8 may for example be like that disclosed in Patent No. 1,278,118, issued on September 10, 1918, to T. W. Dernarest.

It will be apparent that the thermostatic valve it controlled by atmospheric temperature will open communication through pipe Hi When it is desired to prevent the temperature of the compressed air reducing below that existing in bend i2. Therefore a thermostatic valve controlled by the air temperature within bend i2 will produce substantially the same result as obtained by the thermostatic valve 55. Such a modification is shown in Fig. 2 wherein numeral Iii indicates a con-"o1 valve of the butterfly type in pipe l l controlling communication therethrough. The reference numeral 20 indicates a temperature responsive element of any desired type disposed in the path of air flow through the bend i2. The element is connected by a rod 2%, lever 22 and link 23 to the valve l9. By this arrangement when the temperature of air passing through the bend is above a chosen degree, the expansion of ement 26 will close valve 59 and when below said degree the contraction of element 20 will open said valve, thereby producing the same result as obtained with the thermostatic valve it.

With the pipes l to S of the cooling device 3 arranged horizontally as shown in Fig. 1, all drainage of moisture due to the action of gravity will be sluggish. Further, any precipitate in pipes d to s has to traverse first the one pipe and then the next before it can get out of contact with the stream of air flowing to the reservoir 2. Moreover, in case the pipes are not exactly horizontal moisture is liable to collect at low points and thus be constantly in contact with the air stream. In either case the stream of air will tend to pull this precipitate along with it to the reservoir 2. Further, particularly where water collects in pockets, the freezing of such Water might damage the device.

' From the above remarks it will be apparent that it is highly desirable for precipitate to drain out of the cooling pipes and thus out of contact with the air stream as promptly as possible, and this desirable feature is adapted to be obtained by the improved cooling device 31%. shown diagrammatically in Fig. 3.

The cooling device 3A comprises a plurality of parallel arranged cooling pipes 25 to Ell, inclusive, which are adapted to be inclined to the horizontal to any desired degree, such as to the vertical, shown in the illustration. The pipe 25 is connected at its lower end to a pipe 3| leading to the compressor l-while the lower end of pipe Ell is connected to a pipe 32 leading to the reservoir 2. The upper ends of each adjacent :pair of the several pipes are connected by bends 33 to 35 respectively, while the lower ends of pipes 26 and 21 are connected by a bend 35 and the lower ends of pipes 28 and 2d are connected by a bend 31. In this embodiment, the pipe hi including thermostatic valve I5 is connected between the bends 34 and 55. The operation of this structure as so far described is the same as that shown in Fig. 1 and will therefore not be dealt with.

Disposed below the bends 3B and 31 is a moisture receiving and drainage pipe 33 which is preferably inclined to the horizontal in order to provide prompt drainage of moisture in the direction of the automatic drain valve i8 which is connected by a pipe 12 to the lower end of pipe 38.

The higher end of the drain pipe 38 is connected through a restricted communication 39 to the lower end of pipe 35 while the lowest parts of the bends 55 and 31 are open to the drain pipe 38 through restricted communications as and li, respectively.

By this arrangement any moisture which is precipitated in any of the cooling pipes 25 to 29 will promptly drop or flow by gravity to the bottom of the pipe and then through the restricted communications 35, all or ii into the drain pipe as from which it drains into the drain valve i8. The precipitate thus does not have to pass from one pipe to another before it gets out of contact with the stream of air passing to the reservoir 2; but instead, it is drained away and of contact with said air stream as quickly as possible so as to reduce to a minimum the amount of precipitate which may be carried along with the air stream to reservoir 2. Moreover it will be noted that in this structure there are no pockets for moisture to collect where it will be in contact with the air stream.

The broad concept of this embodiment is the provision of a separate drainage communication for each of a plurality of different sections or units which makes up the radiating device. In the structure used for illustration,-the pipe 25 may comprise one section, the pipes 26 and 21 another section and the pipes 28 and 29 a third section, which sections are open to the drain pipe 38 through the restricted communications 39, iii and 3!, respectively. The pipe 36 may comprise a fourth section, this pipe being open to pipe 33 and the drain valve 18 by way of a pipe 42.

Each of the restricted communications 3%, 5d and M may be so small that there will be no material flow of compressed air therethrough by-passing the cooling pipes 25 to 29, or in other words, these restricted communications will have no material efiect upon the efficiency of the cooling device.

Where the reservoir 2 is connected to the lower end of one of the cooling pipes, as pipe St in the illustration, this pipe is open through a portion of pipe 32 to pipe 42 leading to the drain valve l8 as above described. Thus any precipitate in pipe 38 will drain directly to the drain valve. No restriction is required however in the connection between pipe 39 and the drain valve. With this arrangement there will be a tendency for compressed air to by-pass the cooiing pipes 25 to 30 by flowing through the restricted communications 39, 4t and 6!, but as above mentioned, the flow capacity of these communications will be so small that the flow of compressed air through the cooli pipes, as

desired; will be assured. lhe slight flow of air which will occur through these restricted communications is however desirable in that it will expedite the drainage of moisture into the drain pipe 38 and thus out of the path of air flow through the cooling pi es.

Conclusion By using one or more thermostatic valves controlled by the temperature of either the atmosphere or of the compressed air at chosen locations in the cooling device, it will be apparent that the cooling device wil lbe automatically adjusted to prevailing climatic or temperature conditions with no attention from or inconvenience to the engineer, and particularly, when this improved control is associated with a cooling device of the generaltype shown in Fig. 3, a most efficient removal of precipitate from compressed air supplied to the reservoir 2 will be ob:- tained.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is: v

1. A system for cooling compressed air delivered from a compressor to a reservoir for use in an air brake system comprising in combina tion, heat radiating means interposed between the compressor and reservoir and arranged to cool warm compressed air flowing from the compressor to the reservoir, said heat radiating means having a certain heat radiating surface for contact by the stream of air supplied by said compressor to said reservoir, valve means operative to reduce the amount of said surface in contact with said stream of air, and an element responsive to the temperature of said air at a chosen location in said radiating means for controlling said valve means, said element when said temperature is below a chosen degree conditioning said valve means to reduce the amount of said surface in contact with said stream of air and when higher than said chosen degree conditioning said valve means to render the whole of said surface effective.

2. A system for cooling compressed air dc livered from a compressor to a reservoir for use in an airbrake system comprising in combination, heat radiating means interposed between the compressor and reservoir and arranged to cool warm compressed air flowing from the compressor to the reservoir, said heat radiating means having a certain heat radiating surface for contact by the stream of air supplied by said compressor to said reservoir, valve means con trolling a communication which when] closed renders the whole of said surface effective and which when open provides for the flow of said air over only a portion of said surface, and a temperature responsive element controlled, by the temperature of said air at a chosen location in said radiating means for controlling said valve means, said element being operative upon a change in said temperature from a certain relatively high degree to'a lower degree to actuf a'te said valve means from a position closingsaid communication to a position openingsaid' communication. M I

3. A system for cooling compressed air deliv ered by a compressorto a reservoir for use in an air brake system comprising heat radiating" means in the connection between said compressor and reservoir and having at least two outlets through which air is adapted to iiow to saidreservoir,- said outlets being so' arranged munication for each the horizontal, an

that the air flow from the compressor to the reservoir will be through either a portion or the whole of said heat radiating means, and valve means controlled by the temperature of the compressed air at a chosen location in said heat radiating means controlling one of said outlets and operative to close same when said temperature exceeds a chosen degree and open same upon a reduction in said temperature below said chosen degree.

4. Heat radiating means for cooling com pressed air supplied by an air compressor to a main reservoir for use in an air brake system, said means comprising a plurality of heat radiating sections connected in series between said compressor and reservoir and through which said compressed air is adapted to flow for cooling, a moisture receiver, and a separate drainage communication for each of said sections connecting same to said receiver and providing for drainage of precipitate from said sections to said receiver. I

,5. Heating radiating means for cooling compressed air supplied by an air compressor to a main reservoir for use in an air brake system, said means comprising a plurality of heat radiating sections connected in series between said compressor and reservoir and through which said compressed air is adapted to flow for cooling, a moisture receiver, and a separate drainage comof said sections connecting same to said receiver and providing for drainage of precipitate from said sections to said receiver, said sections being arranged to provide for collecting of precipitate due to the action of gravity, and the drainage communication for each section being open thereto at the point of such collection.

6. Heat radiating means for cooling compressed air supplied by an air compressor to a main reservoir for use in an air brake system, said means comprising a plurality of heat radiating sections connected in series with each other between said compressor and reservoir and through which the compressed air is adapted to flow for cooling, said sections being inclined to the horizontal, amoisture receiver disposed below said sections, and a separate and restricted drainage communication for each of said sections open to the lowermost part thereof and connected to said receiver and providing for drainage of precipitate out of said sections into said receiver, the restriction in each of said communications insuring the how of compressed air through said heat radiating sections in passing from said compressor to said reservoir.

7. Heat radiating means for cooling compressed air supplied by an air compressor to a main reservoir for use in an air brake system, said means comprising a plurality of heat radiating sections connected in series with each other between said compressor and reservoir and through which the compressed air is adapted to flow for coo-ling, said sections being inclined to automatic drain valve adapted to receive moisture and to operate automatically to expel such moisture, a moisture receiver dissections and connected to said so arranged as to provide for drainage of moisture into said drain valve, and a separate and restricted drainage communication for each of said sections connecting the lowermost part thereof to said receiver and provlding for drainage of precipitate from said sections' to'said' receiver; the'restriction in each of said communications insuring the flow of compressed air through said sections in passing from said compressor to said reservoir.

8. Heat radiating means for cooling compressed air supplied by an air compressor to a main reservoir use in an air brake system, said means comprising a plurality of heat radiating sections connected in series with each other between said compressor and reservoir and through which the compressed air is adapted to flow for cooling, said sections being inclined to the horizontal, an automatic drain valve adapted to receive moisture and to operate automatically to expel such moisture, a moisture receiver disposed below said sections and inclined to the horizontal and having its lower end open to said drain valve, and a separate and restricted drainage communication for each of said sections connecting the lowermost part thereof to said receiver and providing for drainage of moisture out of said sections to said receiver, the restriction in each of said communications insuring the flow of compressed air through said sections in passing from said compressor to said reservoir.

9. Heat radiating means for cooling compressed air supplied by an air compressor to a main reservoir for use in an air brake system, said means comprising a plurality of heat radiating sections connected in series between said compressor and reservoir and through which said compressed air is adapted to flow for cooling, a moisture receiver, a separate drainage communication for each of said sections connecting the lowermost part thereof to said receiver and providing for drainage of precipitate out of said sections into said receiver, and an automatic drain valve connected to said receiver for receiving moisture therefrom and operative automatically to expel such moisture.

10. Heat radiating means for cooling compressed air supplied by an air compressor to a main reservoir for use in an air brake system, said means comprising a plurality of parallel and vertically extending pipes connected in series with each other between said compressor and reservoir and providing a path for air flow between said compressor and reservoir, a drain valve adapted to receive collected moisture and automatically expel same, a moisture receiver disposed below said pipes and arranged to provide for drainage of collected moisture into said drain valve, and a plurality of restricted drainage communications open to said receiver, each of said restricted communications being also open to a lowermost portion of said path at a different point in said path.

11. Heat radiating means for cooling compressed air supplied by an air compressor to a main reservoir for use in an air brake system comprising a plurality of parallel pipes inclined to the horizontal and connected by bends to provide a single path for air flow, one end of the path being connected to said compressor and the other end to said reservoir, a moisture receiver disposed below said pipes and having a separate communication with each bend connecting the lower ends of said pipes through which precipitate in the pipes connected to the last named bends will fiow into said receiver, and a restricion in each of said communications for limiting the flow of compressed air from said pipes to said receiver to such a degree as to insure the flow of compressed air through said path from said compressor to said receiver.

12. Heat radiating means for cooling compressed air supplied by an air compressor to a main reservoir for use in an air brake system comprising a plurality of parallel pipes inclined to the horizontal and connected by bends to provide a single path for air flow, one end of the path being connected to said compressor and the other end to said reservoir, said bends being so arranged that the ends of said path are at the lower ends of the two end pipes, a moisture receiver disposed below said pipe and having a separate communication with each of the lowermost parts of said path including the ends thereof, through which precipitate in said pipes is adapted to flow into said receiver, and a restriction in each of said communications, except that open to the end pipe connected with said reservoir, for limiting the flow of compressed air to said receiver to such a degree as to insure the flow of compressed air through said path in traveling from said compressor to said reservoir.

RALPH T. WHITNEY.

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