Semi-recirculatory System For A Clothes Dryer

Abstract

The invention provides a clothes dryer having a diverter means in the exhaust duct so as to provide a recirculation of the exhaust air back through the wet clothes during the early stages of the drying cycle. After the temperature of the exhaust air has reached a certain upper temperature, the diverter means moves to a non-interfering position permitting the exhaust of air through the exhaust duct of the dryer.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to clothes dryers and, more particularly, relates to a clothes dryer having a recirculating system for the air provided for drying purposes.

2. Description of the Prior Art

In domestic clothes drying units the drying function is achieved by heating the air taken into the clothes dryer and then causing it to pass through a suitable drum where the clothes to be dried are tumbled to thereby intermix them with air and vaporize the moisture within the clothes. This drying has been accomplished by continuously taking fresh air into the dryer cabinet and then heating it and passing it through the clothes holding drum and then exhausting it outside the dryer cabinet or, alternately, by utilizing a clothes drying cycle in which air is passed through the heater, the wet clothes and then through a means which dehumidifies the air so that it may be reheated for recirculation through the damp clothes. The second of these methods is no longer utilized very much since it unduly complicates the apparatus which must be provided within the dryer to provide dryinG for the clothes. Thus, the majority of dryers now on the market utilize a system wherein fresh air is heated and then circulated through the clothes being dried and then exhausted from the cabinet of the unit. Initially, since the heating means within the dryer must not only heat the outside fresh air but also wet clothes and the enclosure in which they are housed, there is a time lag before a great deal of drying is accomplished so that the total drying cycle can be of fairly long duration.

In an attempt to avoid such a long time duration and in an attempt to speed up the total drying operation, dryer systems have been utilized in which the amount of air that is passed through the clothes during initial drying is restricted so that the initial temperature of the air entering the enclosure in which the clothes are housed is somewhat higher to facilitate a quicker heating of the clothes so that a proper drying temperature is more readily reached. U.S. Pat. Nos. 2,569,515 and 2,970,383 show examples of such a drying arrangement. Such an arrangement, however, loses the sensible heat which is present in the air being exhausted from the dryer cabinet, even though the total flow of air being exhausted is considerably lower than previous dryer arrangements.

Accordingly, it would be advantageous to provide a dryer arrangement in which the sensible heat remaining in the air that had been initially utilized to dry and heat the damp clothes was not lost by exhausting it from the dryer cabinet. Such, then, would represent an extremely advantageous arrnagement since it would reduce the total drying time, and the same would have wide utility since it is fairly simple in operation.

SUMMARY OF THE INVENTION

The invention provides a dryer having an additional duct contained within the dryer cabinet which provides recirculation of drying air back to the drum in which the clothes are retained. An exhaust duct includes a damper which diverts air to the recirculating duct during start-up of the drying cycle. Recirculating the heated air back into the drum in which the clothes are contained yields a much quicker temperature rise within the clothes than has heretofore been obtained and, therefore, the temperature needed for the main portion of the drying cycle for the clothes can be reached more quickly. A thermostatic control, disposed in the exhaust system, is provided for the damper so that when the air temperature of the damp clothes reaches approximately 150.degree., the exhaust damper goes to an open position so that the heavily moisture laden air can be exhausted from the dryer cabinet and a continuous flow of fresh air from outside moved inwardly to be heated and then passed through the clothes containing drum to complete the drying cycle. Due to the recirculation of initial intake air, a dryer is provided having a drying cycle which considerably decreases the amount of time heretofore experienced for the drying of clothes.

DRAWING DESCRIPTION

For a better understanding of the invention, reference may be had to the preferred embodiment, exemplary of the invention, shown in the accompanying drawings, in which:

FIG. 1 is a perspective view of a dryer incorporating the principles of my invention, partly in section, and showing the exhaust and recirculating ducts;

FIG. 2 is a cross-sectional view of the exhaust duct and the damper operating arrangement; and

FIG. 3 is a simplified circuit diagram utilized in the practice of my invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring specifically to FIG. 1, a dryer 10 includes a dryer cabinet 11 that can be seen to include an access door 12 and a clothes containing basket or drum 14. The dryer cabinet 11 also includes a heater housing 16 containing a resistance heater element 18 which is circumferentially disposed within the heater housing 16. The resistance heater 18 thereby heats a flow of air which passes through basket or drum 14 so as to dry clothes contained therein.

The perforated inner door 20 at the front of clothes basket 14 provides for the discharge of air from the clothes basket so that it may be lead downwardly through a collector discharge conduit 22. A series of perforations 21 formed in perforated inner door 20 are equidistantly spaced so as to provide for an air flow through the basket that substantially encompasses the full cross-sectional area of the drying basket 14 as air passes from the rear to the front of the basket 14. Entrance air to be supplied to the drying basket 14 enters at the front of the dryer cabinet 11 substantially as indicated by the arrow A and then flows backwardly past the edge of the collector discharge conduit 22 as indicated by the dotted arrow B and then enters circumferentially around the heater housing 16 as indicated by the arrow C so as to be heated by the resistance heater 18 and from thence it moves through a series of perforations 24 formed in the back side of the clothes dryer basket 14. The perforations 24, of course, are spaced entirely over the back area of the clothes drying basket 14 in a substantially equally spaced relationship therebetween so as to provide the uniform flow path for the flow of air moving toward the front of basket 14.

Air that enters the collector discharge conduit 22 is lead downwardly within the dryer cabinet 11 so as to discharge air to a fan means 25 which communicates with an exhaust conduit 26 that extends from near the front of the dryer cabinet to the back thereof. The fan means thereby provides the driving force for the circulation of air within the dryer cabinet 11. Discharge conduit 26 exhausts air outwardly of the cabinet 11 to an exhaust port 28 located at the very rear of the cabinet 11.

Joined to the exhaust duct 26 adjacnt its connection with fan means 25 is recirculating duct 30, with this duct forming substantially a "Y" connection with exhaust duct 26 to provide a fairly streamlined flow path for air which passes into this duct. Recirculating duct 30 is connected at its rear and exhausts to a rectangular, upwardly extending duct 32 which opens into heater housing 16. THe duct 32 extends upwardly at the very rear portion of dryer cavinet 11 so as to easily communicate with the heater housing 16. Thus, any air flow which moves downwardly through collector discharge conduit 22 and then flows into exhaust duct 26 and from thence to recirculating duct 30, will pass upwardly into heater housing 16 and there again be heated by resistance heater 18 so as to pass through perforations 24 and again heat the clothes in dryer basket 14 and evaporate a portion of the moisture contained in them.

In order to recirculate substantially all the air passing downwardly through collector discharge conduit 22, a damper 34 is positioned in the exhaust duct 26 so as to partially close off this duct to air flow, so that substantially all the air discharged downwardly through collector discharge conduit 22 passes into recirculating duct 30. Referring now to FIG. 2, the exhaust duct 26 can be seen in cross-section with the damper 34 in a nonactive position and with the mechanism for movement of this damper more precisely illustrated.

The damper 34 is pivotally mounted within the duct 26 by a shaft 36 journaled in the duct 26 and with the damper 34 fixedly mounted on the shaft so as to rotate with it. The outward extending rightward end of the shaft 26 mounts a crank member 38 so that the crank member 38 serves as a driving member to dirve the shaft 36 during its rotation. A biasing means comprising a spring 40 extends between a fixed bracket 42 mounted on the discharge conduit 26 and a connection 44 mounted on and rotatable with the crank member 38. Spring means 40 thereby resiliently biases damper member 34 in a direction tending to close the damper 34 so as to provide for recirculation of drying air within the dryer cabinet 11. In order to open damper 34 so as to permit the circulating air to pass downwardly through collector discharge conduit 22 and then outwardly through exhaust port 28, the damper mechanism includes a solenoid means 46 attached by a bracket means 48 or the like to the discharge conduit 26 and attached to the crank member 38 by a connection 45, with this connection taking the form, for example, of a pivoted crank means so as to accommodate the rotational movement of the crank member 38.

The solenoid means 46 includes a reciprocating plunger member 50. As illustrated in FIG. 2, the solenoid plunger 50 is in its most extended condition so that it has rotated damper 34 to its closed position. An electromagnetic means 52 of solenoid means 46 when not energized permits the solenoid plunger 50 to be telescopically advanced due to the biasing effect of spring 40 which thereby moves the damper 34 into a closed position within discharge conduit 26. It can be easily seen from the foregoing description that the discharge conduit 26 is substantially nOrmally closed relative to a flow of air therethrough by the damper 34 and that this damper only opens upon electrical actuation of the solenoid means 46 and the concomitant movement of the solenoid plunger 50 telescopically inwardly (towards the left in FIG. 2) to rotate the damper 34 into an open position.

The operation of my invention now can be easily understood with particular reference to FIG. 3 which shows a simple control system for the operation of a dryer having a recirculation of drying air. A three lead power supply line including lines L.sub.1, L.sub.2 and neutral N with 240 volts being present between lines L.sub.1 and L.sub.2 and 120 volts being present between either of these lines and neutral N are provided for attachment to the circuitry which actuates the dryer 10.

A sequence control timer 54, including contacts 56, 58 and 60, is attached to the L.sub.1 side of the source of electrical supply so that engagement of th contacts 58 or 60 with the contact 56 will provide a flow of electrical energy to these two contacts. contact 58 of the sequence control timer is attached to a lead 62 which extends to a door switch 64 that is closed when the access door 12 of the dryer 10 is closed. Door switch 64, in turn, is attached to a lead 66 that extends to a thermal overload protector 68 of a motor 27 that drives fan means 25. Overload protector 68 is electrically connected to a main winding 70 of the motor 27 and also to a start winding 72 thereof, with both of these windings being in parallel and connected through to the neutral side N of the power supply by a lead 74. By this arrangement then, a circuit is completed from the L.sub.1 side of the power supply to the netural N side thereof for energization of the electric motor 27 which drives the fan means 25 and thereby provides a forced flow of air through the dryer basket 14.

Energization of the resistance heater means 18 for the dryer 10 is accomplished by a lead 76 which extends from the L.sub.2 side of the power supply and is connected to the centrifugal switch 78 of the motor which, in turn, is connected to another lead 80 that extends to and is in electrical connection with the resistance heater 18. The opposite side of the resistance heater 18 is connected to the L.sub.1 side of the electrical supply source through a lead 81, a safety thermostat 82 which functions to open at approximately 180.degree. and interrupt the power supply to the heater 18 due to an abnormal overheated condition within the dryer 10 and a normally closed regular heat thermostat 84 that is designed to open at above 160.degree. so as to serve as the normal upper temperature limiting means for the operating temperature of the air which passes out of the dryer basktt 14. The safety thermostat is located on the upper right side of the heater HSG 16. Regular heat thermostat 84 is located (not shown) on the front baffle 29. Safety thermostat 82 is connected on the other side by lead 83 to the regular heat thermostat. Regular heat thermostat 84 is connected at its opposite side to a lead 86 that extends to and is an electrical connection with the contact 60 which, as previously set-out, is in electrical contacting abutment with contact 56 of sequence control timer 54. Heater 18 is thereby connected across the L.sub.1 and L.sub.2 sides of the power supply source so as to provide 240 volts electrical potential thereto for rapid heating of the air which passes into the dryer basket 14.

The diverter solenoid means 46 receives its electrical potential by means of the lead 74 connected to the neutral side N of the power supply and extending to a lead 88 in electrical connection with one side of the electromagnetic means 52 of the diverter solenoid means 46. At its other side, the electromagnetic means 52 is connected to a lead 90. The lead 90, at its rightward end, is connected to one side of a selector switch 92 which serves as the actuating means for the recirculation of air. The selector switch 92, at its opposite side, is connected to an exhaust regulation thermostat 94 through a lead 96. This thermostat is normally open and is set to close at approximately 150.degree. F. and then to open again above a temperature of approximately 100.degree. F. It is physically located in the same area as the thermostat 84. A lead 98 extends from the opposite side of this thermostat to place the thermostat 94 and diverter solenoid means 46 in electrical connection, with the lead 86 extending to the contact 60 of sequence control timer 54. This circuit arrangement places the diverter solenoid means 46 and exhaust regulating thermostat 94 across the power supply between the neutral N and L .sub.1 sides thereof.

A timer motor 100 is also provided across the power supply between the neutral N and L.sub.1 sides thereof by means of a lead 102 attached to and in electrical connection with the neutral N side and a lead 104 extending from the opposite side of the timer motor 100 and in electrical connection with contact 58 of the sequence timer control. Timer motor 100 is actuated when the contacts 56 and 58 are in abutting condition and operates to control the total length of the cycle for drying for the dryer 10 by moving the contacts 58 and 60 out of physical engagement with 56 at a predetermined point in time when it is desired to cease the operation of dryer 10.

The operation of my invention can now be easily described. Initiation of a clothes drying cycle places the contacts 58 and 60 into electrical contact with the contact 56 of sequence control timer 54 so as to place the contacts 58 and 60 at the L.sub.1 potential. With these contacts energized, timer motor 100 is actuated and the main and start windings 70 and 72 of the electric motor 27 start the motor so as to provide a positive flow of air through the fan means 25 which circulates air through the clothes drying basket 14. Centrifugal switch 78 is closed with the motor at operating speed so that the heater 18 is actuated to heat the circulating air.

The solenoid plunger 50 of solenoid means 46 is in its normally outside, telescoped position as urged by spring means 40 so that the majority of the air circulating within the clothes basket 14 is recirculated through recirculating duct 30 with only a small portion thereof passing past the damper 34. This conserves and saves a large portion of the sensible heat which has been added to this air through the heater member 18 and that has not been removed by the wet clothes. Heating and drying of the clothes in clothes dryer basket 14 continues until the temperature of the air being discharged from this basket reaches approximately 150.degree., at which time exhaust regulator thermostat 94 closes energizing the electromagnetic means 52 of the diverter solenoid 46 to move the damper 34 to an open position so that nearly all the air passing through collector discharge conduit 22 is discharged outwardly through exhaust port 28.

The maximum extraction rate is now achieved and maximum discharge of moisture occurs through exhaust port 28. Conditioning of the clothes is now regulated through the cycling of the regular heat thermostat. The temperature of the air through the basket 14 continues to rise until a temperature approximating 160.degree. is reached at which time the regular heat thermostat 84 opens breaking the circuit between the L.sub.1 and L.sub.2 sides of the power supply and deenergizing the resistance heater 18.

The regular heat thermostat 84 may then again cycle a number of times, dependent entirely upon the amount of moisture remaining in the clothes contained in dryer basket 14. This cycling continues until the temperature of the clothes in the dryer basket 14 begins final cooling due to timer motor 100 moving sufficiently forward in its cycle to open the contacts 60 relative to the contact 56 in abutment with contact 58. The contact 58 is, of course, maintained in electrical contact with contact 56 for a period of time of sufficient duration so that the motor 27 may provide a continuous flow of air through the drying basket 14 to provide additional drying and some cooling to the dry clothes contained in dryer basket 14.

It should be obvious to one skilled in the art that the described invention provides all the advantages set forth for it in the beginning portion of the specification and, further, that many modifications might be made in the invention that would still fall within the spirit and scope of the description offered.

Claims

What is claimed is:

1. A clothes dryer comprising means defining a drying chamber, an air flow system for supplying air to and for discharging air from said drying chamber, means for heating the air supplied to said drying chamber, said air flow system including ductwork for receiving air discharged from the drying chamber, said ductwork comprising exhaust duct means for exhausting the discharged air, and recirculating duct means for returning discharged air to said drying chamber, diverter means disposed in said ductwork, said diverter means having a first portion causing the air discharged from the drying chamber to be exhausted through said exhaust duct means and a second position for directing at least a portion of the discharged air into said recirculating duct means, and diverter actuating means operatively connected to said diverter means for positioning said diverter means in either one of said first or second positions, said diverter actuating means being responsive to the temperature of the discharged air to position said diverter means in said second position when said temperature is less than a predetermined value, and to position said diverter means in said first position when said temperature is above a predetermined value.

2. A clothes dryer as claimed in claim 1, wherein said diverter means comprises a damper.

3. A clothes dryer as claimed in claim 2, wherein said damper is disposed in said exhaust duct means, and has an open position corresponding to said first position, and an at least partially closed position corresponding to said second position.

4. A clothes dryer as claimed in claim 2, wherein said diverter actuating means comprises spring means biasing said diverter means to one of said first or second positions, and electromagnetic means, when energized, to position said diverter means, against the bias at the spring means, to the other of said positions.

5. A clothes dryer as claimed in claim 4, wherein said electromagnetic means is a solenoid.

6. A clothes dryer as claimed in claim 5, wherein said diverter actuating means includes a thermostat for sensing the temperature of air discharged from said drying chamber, said thermostat being adapted to maintain said electromagnetic means deenergized while the sensed temperature is below a predetermined value, and to effect energization of said electromagnetic means when the sensed temperature rises above a predetermined value.

7. A clothes dryer as claimed in claim 6, wherein said spring means normally biases said diverter means to said second position and said solenoid when energized moves said diverter means to said first position.