US2438120A - Apparatus for dehumidifying air - Google Patents

Description

March 23, 1948.

APP

w. H. FREYGANG 2,438,120

ARATUS FOR DEHUMIDIFYING AIR Filed Jan. 27, 1944 9. mw @W Gttomeg Patented Mar. 23, 1948l UNITED STATES PATENT oFFlcE 2.438.120 APPARATUS FOR DEHUMIDIFYING AIR Walter H. Freyung. Essex Fells, N. J., assigner to Kidde Manufacturing Co., Inc., a corporation of Delaware Application January 27, 1944, Serial No. 519.840

8Claims.

lower than the temperature of the outside air.

for instance, during warm periods such as the summer months. It is also well known that during the aforementioned warm periods temperature and relative humidity are important factors in obtaining body comfort, for the reason that the human body is, to an appreciable extent, influenced by the temperature of the surrounding air, which serves to evaporate the perspiration from the body, the rate at which the perspiration is evaporated from the body into the air being influenced by the relative humidity of the air. Generally, in order to produce a sense of comfort to the average person at rest. a temperature from 68 to 70 F., and a relative humidity of 50 per cent (about 4 grains of water vapor per cubic foot of air) is considered to be a very satisfactory condition of the air. If the temperature is lower than '70 F., the relative humidity should be higher than 50 per cent, or, if the temperature is higher, the relative humidity should be lower, so that the same eifect of comfort to the person is provided.

In the majority of instances, in rooms or enclosures having a temperature of '10 F., the relative humidity has been discovered to be considerably less than 50 per cent and, in some instances, as low as 28 per cent. This very low relative humidity has the effect of imparting to the person a feeling of chilliness even though the temperature may be subsequently increased from '70 to 78 or 80 F. This chilly or cooling eiect is the result of the rapid evaporation of moisture from the skin, the rapid evaporation being due to the low vapor pressure of the atmosphere. Conversely, where extremely high relative humidity exists, a temperature of 70 F., might feel oppressively hot to the person.

From the foregoing, it will be apparent that, in buildings wherein the rooms or enclosures are heated by the atmosphere during warm periods when high temperatures and high relative humidities are prevalent, it is desirable to provide means for controlling or dehydrating the air in a manner whereby an optimum satisfactory relation of humidity to temperature may be established under prevailing temperature conditions in order to protect the room structures and contents against the accumulation of moisture thereon and/or to gain the most in the way of body comfort. This desire is fulfilled by the present invention.

An object of the invention is to provide means constituting a dehumidifying unit or system so constructed or arranged as to automatically effect dehumidication of air within a room or enclosure and in a manner to establish an optimum satisfactory relation of humidity to temperature within the room or enclosure.

Another object of the invention is to provide a unit of the foregoing described character which is simple in construction, durable in use, eilicient in operation, economical in manufacture, and which lends itself to ready movability.

With the above and other objects in view, as will hereinafter appear, the invention consists in the combination, and arrangement of parts hereinafter set forth and illustrated in the accompanying drawing, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

The single gure of the drawing is a schematic view, partly in section, illustrating an embodiment of the present invention.

The dehumidifying unit or system, illustrated in (the sectional view of) the drawing, is adapted to be utilized within a room or other enclosure for dehumidifying the air therein, and comprises a base 8 and an air tunnel or cabinet 9 mounted on the base, having an open front end section I0 and top, bottom, side and rear walls II, I2, I3

y and I4, respectively.

Acabinet is provided with an evaporator I6 of a refrigerating unit, the evaporator being spaced from the rear wall to provide an air passage I1 between the wall I4 and the evaporator.

The evaporator I6 is provided with the usual evaporator coil I8, or thelike, having one end connected to a compressor I8 of the refrigerating unit by means of a pipe 28 and having the opposite end connected, by means of a pipe 2 I, to one end of a coil 22, or the like, of a condenser 23 of the unit, the condenser being disposed within the front end section I of the cabinet. The opposite end of the condenser coil 22 is connected, by means oi' a pipe 26, to the compressor I8, the latter being driven by a motor 26 mounted on the base 8 below the cabinet 9.

An expansion valve 24 is provided in the pipe 2| between the compressor and the evaporator and has a connection 21 connected to a temperature responsive device (not shown) disposed with- In the pipe 2U, thereby to operate .the expansion valve in accordance with temperature variations of the refrigerant issuing from the coil I3.

The'cabinet has mounted therein, between the evaporator and the condenser, air propelling means 28, for instance, a motor 29 equipped with a fan 30 to eilect circulation of air through the cabinet from the inlet opening I to and through the front end section Ill from which the air is discharged into the room for circulation therein. I'he air thus circulated through the cabinet ilows between the coils of the evaporator and condenser and establishes, within the cabinet, an air stream having a relatively cold zone between the evaporator and condenser and a relatively warm zone in front of the condenser due to the air stream being subiected to the cooling and heating inuences of the evaporator and condenser, respectively.

'Ihe circulation of air through the cabinet is controlled by means of a shutter 3| in the cabinet between the evaporator I6 and air propelling means 28, the shutter 3i being provided with adjustable slats or vanes 32 connected to a thermostatically operated control means 33, disposed outside of the cabinet, by means of linkage 34, whereby the slats are adapted to be positioned for controlling the passage of air through the shutter 3i.

The top wall I I of the cabinet is provided with an inlet conduit 35 through which unconditioned or room air may enter the cabinet for a purpose hereinafter described. The passage of air into the cabinet, through the conduit 35, is also controlled by a shutter 36 extending across the conduit 3T and provided with adjustable slats or vanes 31. A thermostatically responsive control device 33 is mounted in the front end section III of the cabinet and in front of the condenser 22, whereby air discharged through the condenser influences the operation of the device 38, the latter beine connected to the slats 31 by linkage 38 for eii'ecting adjustment of the slats to control the passage of air through the conduit 35.

Below the evaporator I6. the cabinet is formed with a sump 40 for receiving water from the coil I8 occasioned by condensation of moisture thereon. the sump having a drain pipe 4I connected thereto whereby the Water may be drained from the sump for convenient disposal.

If desired` the front section of tbe cabinet may be equipped with a glass-wool air iilter 42 to remove dust and impurities from the air discharged therethrough.

A thermostat 45, operated by temperature variation of the air stream, is mounted within the cabinet, adjacent the upper front Seiion Q f conductor 41, while the other terminal of saidl switch is connected to one terminal of the compressor motor 26 by a conductor 48. The other terminal of the compressor motor 26 is 'connected to the other input conductor 48 of the power source by a conductor 60. Both conductors 46 and 48 of the power source are connected to the fan motor 28 by conductors 6| and 62, respectively. Outside of the cabinet, adjacent the opening I6, there is mounted a humidity 'control device, for instance, a hygrostat 63 of the type provided with an electrical switch (not shown), the latter being operated by the hygrostat for making and breaking an electric circuit upon operation of the hygrostat. The terminals of the hygrostat switch are connected in circuit with the conductor 43 of the power source and between the latter and the conductors 41 and 5I as diagrammatically illustrated in the drawing.

In operation, assuming the switches of the thermostat 46 and hygrostat 63 are closed, refrigerant is pumped from the compressor into the condenser 23 and from the latter into the evaporator I6 through the expansion valve 24. From the evaporator I6, the refrigerant is returned to the 'compressor I8 thus completing the cycle of circulation. During the circulation, the refrigerant serves to heat the condenser coil 22 and cool the evaporator coil I8 in the usual manner. Coincident with the circulation of the refrigerant, air is propelled through the cabinet by means of the fan 30 and subjected to the cooling and heating influences of the evaporator and condenser coils as it passes therethrough whereby said air is dehydrated in accordance to a predetermined value, as will hereinafter become apparent.

As the warm or unconditioned room air passes through the evaporator coil I 8. ice will form on the lower portion of the coil and will pre-cool and deflect the air outwardly within the passage I1 where it passes through theupper portion of the coil, moisture condensing on the coil being discharged to the sump for drainage therefrom.

In order to guard against both the upper and lower portions of the evaporator coil becoming blocked by ice and precluding the flow of air through both portions, the thermostat 46, adjacent the upper portion oi' the coil is set to operate at a, predetermined temperature, for instance 35 F. When the temperature of the air, passing through the upper portion of the coil, is lowered to the aforementioned value, the thermostat 46 operates its switch to break the circuit through the conductors 41 and 48 with the result that the compressor is shut down, thus, stopping circulation of refrigerant through the evaporator coil I8 and permitting the temperature of the coil to be raised, by the room air passing therethrough, to a sumcient degree to preclude any appreciable amount of ice from collecting on the upper portion and blocking the same, thereby permitting air to pass through the upper portion of the coil at all times during the circulation oi the air through the cabinet.

In order to cool and dry the air to obtain a humidity value comparable with the temperature of the room and under certain conditions hereinafter made apparent, the rate of now or the.

air through the evaporator is controlled by the thermostatic control means Il, the latter being operatively connected to the shutter 3|. The slats 32 of the shutter 3| are pre-adjusted with respect to the thermostatic control means ll and in a manner whereby operation of the control means n serves to position the slats I2 for controlling the rate of ilow of the air through the evaporator Il. For example, at a room temperature of 80 F.,.the slats of the shutter are adjusted with respect to the thermostatically operated control means 3l until the air passing through the evaporator and shutter reaches a definite rate of flow and with the air having a desirable relative humidity, for instance, fifty per cent, and a desirable temperature, for instance 40 F., it being understood that the rate of ilow of the air with a temperature of 40 F., is sufllcient to meet the cooling requirements of the condenser.

Assuming that the foregoing factors are the optimum operating requirements of the unit and that the same is controlled by the room temperature and the rate of flow of the air through the evaporator and condenser, it will be apparent that should the room temperature vary, for example, rise to 100 F., it would be necessary to compensate for this differential in temperature in a manner to fulfill the optimum operating requirements in order to maintain the efciency of the unit. The invention, in order to compensate for this differential, comprehends the use of a compressor of sufllcient capacity to meet the additional cooling load thus presented to the evaporator and at the same time permit the same rate of flow of the air through the condenser to be maintained and with the temperature of 40 F. When the evaporator is loaded, the expansion valve 24 operates, through the medium of the connection 21, to increase the circulation of refrigerant through the coil I8 to meet the increased cooling demand of the coil.

Separately from or conjointly with the foregoing, the invention also comprehends decreasing the rate of flow of the air through the evaporator in order to maintain the evaporator at optimum temperature to cool the air to the desired 40 F. This decrease in the rate of the ilow of the air through the evaporator is accomplished through the operation of the control means 33, in response to the rise in room temperature, which positions the slats 32 in a manner to reduce the rate of flow of air through and from the evaporator I6.

When the rate of flow of air through the evaporator is reduced and maintained at a temperature of 40 F., it may not meet the optimum cooling requirements of the condenser due to the reduced rate of flow of the air passing therethrough. When this condition prevails, the air passing through the condenser will be heated to such an extent as to cause operation of the thermostatically operated device 38, the latter being set for operation at the highest temperature conducive to proper cooling of the condenser coil. Upon operation of the device 38, the slats 31 will be adjusted in a manner to permit sufilcient room air to enter the cabinet through the conduit 35 and mix with the dehumidifled air in the cabinet and thereby provide sufcient volume of air with a low enough temperature to meet the cooling demands of the condenser coil.

As the air passes through the relatively hot to at least its original temperature and serves as assenso 6 a cooling medium for the condenser coil. in this respect. the unit diiiers from an air cooler for the reason that it functions as its own condensercooler. thereby eliminating the use of cold outside air or water as a condenser-cooler. When the room air, passing through the opening Il, reaches a predetermined relative humidity, the humidity control device or hygrostat I3 operates to open its switch and thus break the circuit through the conductor Il resulting in the stopping of both the compressor and fanmotors 2l and 20, respectively. A predetermined change in the relative humidity serves to operate the hygrostat to close its switch whereby the unit is operated as heretofore described.

.In view of the foregoing description, it will be seen that the present invention provides an improved unit for dehumidifying the air in rooms or other closed spaces. The unit is constructed of a minimum number of parts and is compact in assembly to facilitate movability. The unit is rugged in construction and can readily withstand any rough usage to which it may be subjected.

As various changes may be made in the form,-

construction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.

It is also to be understood that the following claims are intended to cover all the generic and speciiic features of the inventionA herein described, and all statements of the sc-ope of the invention which, as a matter of language, might be said to fall therebetween.

I claim:

1. In a dehumidifier, a housing having oppositely disposed inlet and outlet openings to permit air to be dehumidiiied to be circulated through said housing, a refrigerating unit associated with said housing and having an evaporator and a condenser disposed in said housing adjacent said inlet and outlet openings, respectively, air propelling means for propelling air through said evaporator and said condenser, a shutter mounted in said housing between said condenser and said evaporator for controlling the rate of flow of the air through said evaporator, a thermostat mounted outside of said housing and connected to said shutter for operating the latter, said housing being provided with an inlet conduit between said shutter and said condenser for admitting air into said housing to increase the rate of iiow of the air through said condenser, means for controlling the admission of air into said housing through said conduit and including a thermostat operated by the temperature of the air passing through said condenser, and dual control .means responsive to the temperatures of the air outside and inside of said housing for controlling the operation of said refrigerating unit.

2. In a dehumidifier, a housing having oppositely disposed inlet and outlet openings to permit air to be dehumidifled to be circulated through said housing, a refrigerating unit associated with said housing and having an evaporator and a, condenser disposed in said housing adjacent said inlet and outlet openings, respectively, air propelling means mounted in said housing between said evaporator and said condenser for propelling air through said evaporator and said condenser, a shutter mounted in said housing between said airpropelling means and said evaporator for controlling-the rate of flow of 7 the air vthrough said-evaporator. a therm mounted outside of said housing-and connected to said shutter for operating the latter, said housing being provided with an inlet conduit between said shutter and said condenser for admitting air into said housingto increase the rate of ilow of the air through said condenser, means for controlling the admission ot air into said housing through said conduit and including a thermostat operated by the temperature of the air passing through said condenser, a thermostat mountedin said housing adjacent said evaporator for controlling the operation of said refrigerating unit, and hygrostatlc means mounted outside of said housing adjacent said inlet opening for con.- trollinggthe operation of said refrigerating unit and said 'air propelling means.

3. A dehumidifying unit comprising a compressor, a tunnel having an end inlet, an end outlet and an intermediate inlet, an evaporator in the tunnel between said inlets, means for controlling the ilow ci' air through said end inlet, means for controlling the flow of air through said intermediate inlet, a condenser in the tunnel between said intermediate inlet and said outlet, means in the tunnel between said condenser and said intermediate inlet for drawing air through said inlets, means completing a reirigerating system including means connecting said evaporator and condenser through said compressor, means for controlling the operation of said compressor in accordance with the temperature of air adjacent to said evaporator, means responsive to predetermined temperature conditions in a space to be affected by the unit for actuatingsaid end inlet ilow control means, means operative in accordance with a temperature condition of said condenser for actuating said Aintermediate inlet iiow control means, and means responsive to humidity effects of air in the space for controlling the operation of said compressor and said air drawing means.

4. A dehumidifying unit comprising a compressor, a tunnel having an end inlet, an end outlet and an intermediate inlet, an evaporator in the tunnel between said inlets, means in the tunnel between said evaporator and said intermediate inlet for controlling the ilow of air through the tunnel, means in the tunnel for controlling the air entering said intermediate inlet, a condenser in the tunnel between said intermediate inlet and said outlet, means in the tunnel for drawing air into the tunnel as controlled by said end and intermediate inlet flow controlling means and directing the drawn air against said condenser and through said outlet, means completing a refrigerating system including means connecting said evaporator and condenser through said compressor, means for controlling the operation of said compressor in accordance with the temperature of air adjacent to said evaporator, means responsive to predetermined temperature conditions in a space to be aiIected by the unit for actuating said end inlet flow control means, means responsive to temperature change in the air-adjacent to said condenser for actuating said intermediate inlet flow control means, and means responsive to humidity eiects of air in the space for controlling the operation of said compressor and said air drawing and directing means.

5. A dehumidifying unit comprising a compressor, a tunnel having an end inlet, an intermediate inlet and an end outlet, an evaporator in the tunnel between said inlets, means between said evaporator and said intermediate inlet for controlling assenso thetlowoi'air fromsaidendinlet.meansiorcon trolling the'air from said intermediate inlet.' a condenserinthe tunnel between said intermediate inlet and said outlet, means in the tunnel for drawing air through said inlets, means completing a refrigeratlng system including means connecting said evaporator 'and said condenser through the compressor, said completing means also including an expansion valve connected across the evaporator for operation in accordance with temperature variation 'of the refrigerant from the evaporator, means for controlling the operation of the compressor in accordance with the temperature of air'adiagent to said evaporator, means responsive to predetermined temperature conditions in a space to be aii'ected by the unit for actuating said end inlet iiow control means, means responsive to temperature change in air adjacent to the condenser for actuating said intermediate inlet iiow control means, and means responsive to humidity efrects of air in the space for controlling the operation of said coinpressor and said air drawing means.

6. A dehumidifying unit comprising a compressor, a tunnel embodying an end outlet, an intermediate inlet and an opposite end wall having a low inlet opening, an evaporator in the tunnel next to said end wall having an under portion opposite said low inlet opening and an upper portion opposite the upper portion of said end wall, a condenser in the tunnel next to said outlet, means for forcing air through said intermediate inlet and said low inlet opening to said outlet, means for controlling the air entering said low inlet opening, means for controlling air entering said intermediate inlet, means completing a, refrlgerating system including means connecting said evaporator and said condenser through the compressor, means responsive to room temperature for actuating said low inlet air controlling means, means responsive to temperature at the condenser for actuating said intermediate inlet air controlling means, means responsive to temperature at the upper part of the evaporator for controlling operation of thev compressor, and means responsive to room humidity for controlling operation of the compressor and of said air forcing means.

7. In a dehumidiiying unit adapted to be placed in a room, the air of which is to -be dehumidified, the combination of a refrigerating system including compressor means, evaporator means, expansion valve means and condenser means; air ow conduit means having inlet means adapted to receive air from the room and outlet means adapted for delivering the air to the room, said conduit means containing said evaporator and said condenser means with said evaporator means in upstream air flow cooperation with said condenser means; air draft generator means for effecting said flow; means automatically operative during the operation of the unit for controlling the ilow of refrigerant: means responsive to room temperature for controlling the room dehumidifying effects of said evaporator means; and means for maintaining the temperature of said evaporator means at substantially a predetermined value.

8. In a portable humidifying unit adapted to be placed in a room, the air of which is to be dehumidiiled, the combination of a cabinet, a refrigerating system in said cabinet including an evaporator and a condenser, a tunnel extending through said cabinet having inlet and outlet means in communication with the room, said evaporator being positioned in the tunnel next to condenser.

WALTER H. FREYGANG.

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

Number UNITED STATES PATENTS Name Dato Newton Oct. 1, 1941 McGrath Sept. 22, 1942 Shipley Dec. 22, 1931 Parcaro Sept. 12, 1939 Number Ramsey June 8, 1943 FOREIGN PATENTS Country Date France Nov. 23, 1933 France Jan. 24, 1918

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