US2046716A - Method and apparatus for conditioning air - Google Patents

Description

AFFAHAI Us. 1 1 5.

Filed July 15, 1931 APFAHA! US.

Patented July 7, 1936 UNITED STATES PATENT OFFICE BIE'I'HOD AND APPARATUS FOR CONDITIONING AIR Application July 13, 1931, Serial No. 550,383

'lClaims.

The present invention relates to methods and apparatus for conditioning air.

The object of the present invention is to provide a simple and positive method and apparatus for conditioning air and for controlling the condition of the air.

With this object in view, the present invention contemplates passing an integral stream of air through a conditioning chamber having a plurality of conditioning devices, passing a portion of the air therethrough without conditioning, and controllably conditioning another portion of the stream by relatively varying the operation of such devices to control the condition of the stream as a whole, without varying the proportions of the different portions. In the preferred form of the invention, the conditioned portion of the air is directed in several sections through a plurality of water sprays and the operation of the several sprays is controlled in accordance with the degree of conditioning desired to be l obtained. The invention provides for an accurate control of conditioning without the necessity of complicated or expensive by-pass ducts as are employed in some prior constructions.

' In the accompanying drawing illustrating what is now considered the preferred form of the invention, Fig. 1 is a diagram of the complete air conditioning system and Fig. 2 is a sectional elevation of the preferred form of air washer.

The invention is herein illustrated and described as embodied in a system for supplying cooled or rehumidified air to an enclosure such as a room, an auditorium, or a railway vehicle.

In the illustrated embodiment of the invention, the air to be conditioned comprises a mixture of fresh air with air recirculated from air closure I. The system comprises a delivery 1. 2 leading to the enclosure I, an exit duct 3 leading from the enclosure, a fresh air duct 4 connecting with the exit duct, and a conditioning chamber 6 connected with the delivery duct and containing a plurality of water washing or spray devices 8, of the construction shown in Fig. 2. In Fig. 1, three of these devices are shown, arranged transversely across the duct. A space 9 is left above the uppermost spray device, forming a bypass. of constant cross-section, preferably about equal to the cross-sectional area of one of the spray devices.

Each device is preferably of the type disclosed in my copending application Serial No. 395,402, filed September 26, 1929, now Patent 1,936,243 issued Nov. 21, 1933, having screens or filters ll on the inlet and outlet sides thereof and a plurality of spray nozzles I! for spraying water into the air current in a direction opposite to the movement thereof. A filter 14 may be placed in the space 9, if desired. Water is admitted to the nozzles of the spray devices by pipes indicated respectively at-IO, l8 and 20. The water for all of the devices is collected in a drain tank 22. The water is circulated by a pump 24 from the tank 22' through a pipe 26 to a cooler 28, which cools the water in any suitable manner, as by contact with ice or by surface cooling with a refrigerant circulated through the cooler by pipes 30. From the cooler, the water is pumped through a pipe 32 which connects with the feed pipes for the spray devices.

In operation, the air to be conditioned passes through the conditioning chamber in two portions, of substantially uniform proportions. One portion passes through the space 9, and the other portion passes through the washer. The latter portion of the air is conditioned by the sprays and is then mixed with the first or unconditioned portion. In the use of the apparatus for dehumidiiying, the air passed through the washer units is cooled by contact with the water. For maximum conditioning, the air passed through the washer units is carried to a dew point determined by the temperature of the water, and the wet and dry bulb temperatures of the entire stream are determined by the mixture of the two portions. For less than maximum conditioning, the portion passed through the washer units is subjected to contact with a diminished quantity of water, without substantially altering the relative proportions of the air passed through the washer units and that passed through the space 9.

To control the degree of conditioning, the first and second spray devices are variably operated, either by varying the amount of water handled by each or by cutting them into or out of service in accordance with the degree of conditioning necessary. The bottom spray device is operated continuously.

The control of the sprays is eflected in the following manner: in each of the pipes l8 and I8 is included an automatic diaphragm valve, the valves being indicated at 36 and 38 respectively. The valves are controlled by a compressed air line Ill leading to a recording and. controlling thermostat 42, the operation of which is controlled in the usual manner by a dry bulb thermostat 44 in the exit duct 3 and sensitive to the dry bulb temperature of the enclosure.

Compressed air is supplied to the controller 42 by a line 50. The operation of the valves 36 and 38 is such that water is supplied to the sprays at a pressure up to a maximum of about 30 pounds. At about 20 pounds water pressure in a device of the construction shown, the spray collapses, and the degree of conditioning is considerably reduced, although some conditioning action is maintained even at very low water pressures. quence, that is, the pressure is first reduced by the valve 36, from the maximum pressure down to a pressure at which the spray collapses; then the valve 38, which has been maintained ,wide

open, is similarly throttled...This action'occurs automatically upon a reduction of the tempera-- ture; on an increase in temperature, the reverse procedure takes place. may be set to operate in unison, but inasmuch as it is desirable to guard against collapsing of both sprays simultaneously, 'the above operation is preferred.

The relative humidity of the air in the enclosure may be regulated by varying the tem-.

perature of the circulated water in any accepted manner, such as by a wet bulb control in the air stream or in the enclosure. However, wet bulb controls usually require considerable attention. The invention, in its preferred form; regu-' lates the humidity of the air, without the necessity of using a wet bulb control, by maintaining a substantially constant temperature of the air emerging from the lowermost washer unit, which.

is operated continuously. This is accomplished by a thermostat 5| placed on the outlet side of the unit and controlling through a line 52 athree-way valve 53 placed at the junction of the waterline 32 and a by-pass 54 connected around the cooler 28. Since the air is saturated in passing through the lowermost washer unit, the wet and dry bulb temperatures are the same. By by-passing a variable amount of water around the cooler, the temperature of the water is varied to maintain the air emerging from the lowermost washer section at a constant temperature. This control, in combination with the dry bulb temperature control 44, serves to maintain nearly constant temperature conditions in the enclosure. For example, assuming that after the desired conditions have been established, if the dry bulb temperature rises, the thermostat 44 calls for more water to be sprayed through the washer units, thereby acting to restore the temperature to its initial value. If the. wet bulb temperature rises, the thermostat -5| calls'for a reduced water temperature, thus acting to restore the wet bulb temperature of the air to substantially its initial value; Ordinarily, a change of one of the factors causes a; momentary change in the other, but both controls operate automatically to bring about a restoration of the desired conditions. Usually, -a change in dry bulb temperature is accompanied by a similar change in the wet bulb temperature, so that both the quantity and temperature of the water are varied under the action of the two controls. By the use of two simple thermostat controls, the air may be maintained substantially at a uniform condition.

When only a small degree of conditioning is required, it may be found that the .first and second washer units do not operate with full sprays for a sufiicient time to maintain their filters wet. The collapsed sprays providefor some wetting of the filters, but ifit is desired to The valves are set to operate in se- If desired, the valves' maintain the best filtering action, each valve 36 and 38 is provided with a time operated mechanism, indicated generally at 56, to open the valves intermittently for a short period, sufflcient to wet the filters, regardless of the pressure in the compressed air line. Alternatively, the filters may be wet with oil from a tank 58 controlled by a hand valve. This procedure permits wetting of the filter H in the space 8.

.The air leaving the conditioning chamber is thoroughly mixed in the duct 2 before passing to the enclosure. The circulation and delivery of the air are maintained by any suitable fan, indicated diagrammatically by a fan 60 in the duct 2.

It will be seen that the invention provides for ,close and accurate control of the conditioning of the air. The invention operates on an integral stream or current of air, one portion of which is controllably conditioned, the other portion being subjected to no conditioning action. The'conditioning of the former portion is preferably controlled by varying the conditioning of different sections thereof, without altering the proportions of conditioned and unconditioned air. In passing through the filters, there is necessarily some turbulence of flow and consequent mixing of the different portions. The proportions of air in the two portions are substantially constant, although a slight variation may be introduced by the changes in resistance due to variations in the sprays.

Although the illustrated embodiment of the invention employs a fresh air duct 4 for mixing some-fresh air with the recirculated air, in ordinary applications, this is unnecessary. In theaters and auditoriums, a sufllcient change of air is afforded by persons passing through doorways. In railway vehicles, the occasional opening of the doors admits enough fresh air under the draft caused by the motion of the vehicle.

' Although the feature of variably conditioning'portions of an integral stream may be applied to the treatment of any air, it is preferred, in most instances, to condition a mixture of fresh and returned air as a whole, in accordance with the system shown generally in the drawing. In this system, substantially the entire stream is brought efliciently to its desired condition, without the necessity of providing complicated by-pass control mechanisms for varying proportions of conditioned and unconditioned air, as have been employed in some prior constructionsl Having thus described the invention, what is claimed is:

1. Air conditioning apparatus having, in combination, a chamber, a plurality of spray units extending partially across said chamber, means for supplying water to the spray units, each spray unit having a filter, individual valves for the spray units, means controlled by the condition of the air for operating the valves to vary the water supplied to the spray devices, and independent means for intermittently supplying water to the spray units to wet the filter thereof.

2. Air conditioning apparatus having, in combination, a chamber, a spray device in the chamber for conditioning the air passing therethrough, a filter, means for throwing the spray device into and out of operation to control the conditioning of the air, and mechanism for intermittently throwing the spray device into operation momentarily to wet the filter while said device isinoperative to condition the air.

3. Air conditioning apparatus having, in combination, a chamber, a plurality of spray units extending partially across the chamber, means for supplying water to the spray units, means controlled by the dry bulb temperature for controlling the supply of water to certain of the spray units, and means controlled by the temperature of the air passed through one or the units to vary the temperature of the water.

4. A method of conditioning air which consists in delivering an integral stream of air, variably conditioning different sections of the stream with water, spraying one of said sections with suflicient water to substantially completely saturate the air in said section, and varying the water temperature to maintain substantially constant the air temperature of said saturated air.

5. A method of conditioning air supplied to a room comprising withdrawing air from the room in an integral stream, variably conditioning diflerent sections of the stream with water sprays, including spraying sumcient water in one of said sections so substantially completely saturate the air in said section, varying the amount of water supplied to the other sections to maintain substantially constant the temperature of the air in the room, and varying the temperature of the water supplied to all of the sprays to maintain substantially constant the temperature of the air in the section in which the air is saturatedtomaintainthehumldltyolthcwhole stream substantially constant.

6. The method of conditioning air supplied to a room comprising withdrawing air from the room, variably conditioning at least a portion of 5 the air by spraying the air with water, spraying sumcient water in a section of the stream to completely saturate the air in such section, measuring the temperature of the air withdrawn from the room and the temperature or the saturated air in such section, controlling the amount of water supplied in accordance with one of said temperatures, and controlling the temperature of the water in accordance with the other of said temperatures.

7. Air conditioning apparatus comprising means for spraying a stream of air with water including means for spraying sufllcient water in a section of the stream to completely saturate the air in such section, means for varying the temperature oi the sprayed water, means for mixing and supplying all of the air to a room, a control device operating in accordance with the temperature of the mixed air, a control device operating in accordance with the temperature or the completely saturated air, means for varying the amount of water sprayed in accordance with one of said temperature, and means for controlling the temperature or the water sprayed in accordance with the other of said temperatures.

SAMUEL M. ANDERSON.

am ,1; i 1? CERTIFICATE or CORRECTION.

Patent No. 2,046, 716. July 7, 1936.

SAMUEL M. ANDERSON.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, first column, line 54, for "rehumidified" read dehumidified; page 3, first column, line 24, claim 5; for "so" read to; and second column, line 28, claim '7, for "temperature" read temperatures; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of September, A. D. 1956.

Henry Van Arsdale (Seal) Acting Commissioner of Patents.

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