US3496731A - Dehumidifier control system - Google Patents

Description

Feb. 24, 1970 c. E. SHOLTES 3,496,

DEHUMIDIFIER CONTROL SYSTEM Filed May 8, 1968 CONDENSER-\ 24 26 LE/VAPORATOR L CONDENSATE BUCKET HUMlD|STAT--'- wwwessrzs: \NVENTOR Carl E. Sholtes c i L ATTORNEY United States Patent 3,496,731 DEHUMIDIFIER CONTROL SYSTEM Carl E. Sholtes, Columbus, Ohio, assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed May 8, 1968, Ser. No. 727,406 Int. Cl. F25d 21/14, 29/00 U.S. Cl. 62-173 3 Claims ABSTRACT OF THE DISCLOSURE The titled control system in which a humidistat and a condensate bucket switch are connected in series for controlling energization of the dehumidifier compressor motor and fan motor and in which a signal device for indicating a full condensate bucket is connected in parallel with the bucket switch so that it is energized only when the bucket is full and the humidistat is calling for dehumidification.

BACKGROUND OF THE INVENTION Field of the invention This invention pertains to the art of dehumidifier control systems.

Description of the prior art SUMMARY OF THE INVENTION In accordance with my invention, I provide in a dehumidifier having a conventional refrigeration system and a bucket to receive condensate, a control system which includes a humidity responsive switch and a condensate level responsive bucket switch in series with the driving means for the refrigeration system, and electrical signal means in parallel with the bucket switch and of sufiiciently high resistance that it will be energized only when the bucket switch is open and the humidity responsive switch is closed. Thus the need to empty the condensate bucket is indicated only when the need to dehumidify also exists. This arrangement permits the use of single pole, single throw switches for both the humidistat and the bucket switch.

DRAWING DESCRIPTION The single figure is a partly diagrammatic and partly schematic view of a dehumidifier having a control system according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The dehumidifier illustrated is typically enclosed within a cabinet indicated by the broken-line rectangle and includes, as the components of major interest in connection with this invention, a refrigeration system, and an electric control system.

The refrigeration system is generally conventional and includes the usual hermetic refrigerant compressor 12 containing an electric motor 14. The compressor pumps refrigerant to the fin and tube condenser 16 where it is condensed and passes through the capillary line 18 to the evaporator 20. The evaporator may be in the form of a double, spiral tube arrangement, from which the refrigerant then passes through suction line 22 back to the compressor. Electric motor 24 drives fan 26 and draws air through the evaporator and condenser and then exhausts it back to the room in a dried and warmed condition, the path of the air flow being indicated by the arrows.

The condensate which collects on the evaporator 20 as it passes therethrough drips down onto shelf means 28 from whence it is directed into the condensate bucket 30 which is pivotally mounted at point 32. The oil center pivotal mounting at 32 results in the bucket producing an increasing moment in a clockwise direction as the level of condensate in the bucket increases. This increasing moment is used to actuate the single pole, bucket switch 34 of the electric control system when the level of condensate in the bucket approaches an overflow condition. An adjustable spring (not shown) is provided to oppose the movement exerted by the bucket to permit changing the shut-off level by the user. It will be appreciated of course that the accumulation of condensate may be sensed by float means or other conventional means for operating the bucket switch 34.

The control system means responsive to the level of humidity comprises a humidistat 36 provided with the single pole, single throw, switch 38. The humidistat may be of conventional character in which a humidity responsive element such as a nylon membrane or a human hair element is provided which stretches when the humidity is relatively high and is connected to the electric switch 38 through linkage mechanism not shown to control the switch position in accordance with the humidity level sensed. Thus, as the sensed humidity level rises above, and falls below, a predetermined humidity range to which the humidistat is set, the switch 38 is operated to closed and open positions, respectively.

An electric signal device such as the indicator light 40- is provided to furnish a signal when the level of condensate in the bucket causes bucket switch 34 to open while the need for dehumidifying exists as evidenced by the humidistat switch 38 being closed.

The circuits formed by connecting the various electrical components includes a first circuit which, beginning at one side 42 of the electrical power source includes the fan motor 24 and the compressor motor 14 connected in parallel with each other, line 44 connecting the one side of the humidistat switch 38 to one side of the motors, line 46 connecting the other side of the humidistat switch to one side of the bucket switch 34, and line 48 connecting the other side of switch 34 to the other side of the power source. Thus, the first circuit provides a series connection of the humidistat and the bucket switch to the compressor and fan motors.

The second circuit connects the indicating light 40 in parallel with the bucket switch 34 as shown. In accordance with the preferred embodiment of the invention, the signal light 40 is a neon high brilliance lamp with a resistor, providing approximately 30,000 ohms resistance, such as is available from Jemco Engineering Company. The fan motor 24 and the compressor motor 14 have a comparatively low resistance, such as approximately 25 ohms for the fan motor, and approximately 3 /1 ohms for the compressor motor main windings. Accordingly, when the bucket switch 34 opens in response to a full bucket, and with the humidistat switch closed, the high resistance of the indicating light results in substantially all of the voltage drop occurring across the signal light and the current flow through the motor and fan motor and compressor motor being sufiiciently low that their operation is precluded. It will be appreciated that the signal means 40 may take the form of a buzzer or other electrically energized signal device with the proviso that sufficient resistance be present to prevent the operation of the motors 14 and 24 when the bucket switch 34 is open.

The circuit is illustrated with the existing conditions of a condensate level in the bucket sufficiently low that the bucket switch 34 is closed, and with the sensed humidity level being sufficiently low that the humidistat switch 38 is open so that the motors 14 and 24 are deenergized. Then as the humidity level about the dehumidifier rises, the humidstat switch closes and energizes the motors through the first series circuit noted. The 'humidistat switch will close and open in response to rising and falling relative humidity, respectively, so that the dehumidifier will cycle accordingly until the condensate level in the bucket 30 rises sufiiciently that the moment produced causes the bucket switch 34 to open. Then if the humidistat switch is open, indicating there is no need for dehumidifier operation, the signal light will remain deenergized. However, as a need for dehumidification rises and the humidistat switch closes, the signal light 40 will be energized, indicating to the user that the condensate bucket needs to be emptied for further operation of the dehumidifier.

It will be appreciated that the described arrangement results in a signal only when both the condition of a full condensate bucket, and the need for dehumidification, are concurrently present. The arrangement is also advantageous in that the reliable, less expensive, single pole, single throw switch 34 may be used rather than a single pole, double throw switch. Also, this arrangement permits the manufacturer to readily delete the signal light as an option without any changes in the basic wiring or in the bucket switch being required.

I claim as my invention:

1. In an electric dehumidifier including a refrigeration system having electrical driving means, and a bucket to receive condensate, a control system comprising:

first electrical switch means responsive to sensed humidity above and below a predetermined humidity 4 range to operate to closed and open positions,

respectively; second electrical switch means responsive to a level of condensate in said bucket above and below a predetermined level to operate to open and closed positions, respectively; electrical signals means; first circuit means connecting said driving means, said first switch, and said second switch in series with a source of electrical power; second circuit means connecting said electrical signal means in parallel with said second electrical switch means, so that said electrical signal means is energized only when said first electrical switch means is closed, thereby indicating a need to operate said dehumidifier, and said second electrical switch means is also open; and said electrical signal means has a comparatively high resistance relative to the resistance of said driving means to restrict electrical current through said driving means, when said second switch is open, to a sufficiently low value that operation of said driving means is prevented. 2. In a dehumidifier according to claim 1: both said first and second switches comprise single pole, single throw switches. 3. In a dehumidifier according to claim 1: said electrical signal comprises a light.

References Cited UNITED STATES PATENTS 2,272,099 2/1942 Smith 62-173 2,549,547 4/1951 Trask 62176 2,725,196 11/1955 Trittschuh 62--l76 3,044,272 7/1962 Eisendrath 62-488 WILLIAM J. WYE, Primary Examiner US. Cl. X.R.

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