US2505041A - Drying apparatus having operation sequence control - Google Patents

Description

Apnl 25, 1950 H. F. GORSUCH 2,505,041

DRYING APPARATUS HAVING OPERATION SEQUENCE CONTROL Filed Dec. 29, 1945 2 Sheets-Sheet 1 INVENTOR HAROLD F. GORSUCH.

WIT QESSEYS: 8 Fla. 3. 7 BY ATTORNEY April 25, 1950 H. F-. GORSUCH 2,505,041

DRYING APPARATUS mvmc OPERATION szqmaucs coN'noL Filed Dec. 29, 1945 2 Sheets-Sheet 2 I INVENTOR- HAROLD F. GORSUCH.

&. I I @QQW ATTORNEY WITNESSES:

Patented Apr. 25, 1950 DRYING APPARATUS HAVING OPERATION SEQUENCE CONTROL Harold F. Gorsuch, Mansfield, Ohio, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application December 29, 1945, Serial No. 638,353

7 Claims. 1

My invention relates to drying apparatus, more particularly to apparatus for drying fabrics or the like, and has for an object to provide improved apparatus of this kind.

A further object of the invention is to utilize the heat remaining in the drying chamber of a -quence of drying steps automatically, at the conclusion of which the drier is rendered inactive.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

Fig. 1 is a vertical section taken along the line I-I of Fig. 2 and showing a form of clothesdrier controlled in accordance with my invention;

Fig. 2 is a sectional view taken along the line 11-11 Of Fig. 1;

Fig. 3 is a diagram of the electrical connections of the control apparatus used to control the drier shown in Figs. 1 and 2;

Fig. 4 is a view similar to Fig. 1 and showing a second embodiment of the invention; and

Fig. 5 is a diagram of the electrical connections for the drier shown in Fig. 4.

Reference will now be had to Figs. 1 to 3, inclusive, wherein I have elected to show my invention applied to a clothes drier of the domestic type and provided with a housing structure ID, the front wall H of which is provided with an access opening I2 and a suitable hinged door l3 for. closing the opening. The housing II] also includes a back wall It for suitably supporting a bearing l5 in which a shaft 16 is ournaled. The latter supports a basket H for containing the clothes to be dried, which basket l'l includes a perforate side wall 18, a number of the perforations being shown at l9. The basket I1 is provided with a plurality of inwardly-extending vanes 2| which function to tumble the clothes during rotation of the basket. The front end of the basket I1 is provided with an access opening 22 which registers with the access opening I2 of the housing.

Agenerally cylindrical baille 23 is disposed 2 within the housing l0 and encloses a drying chamber 24 within which the basket rotates. An upper portion of the baille 23 is recessed to provide a cove 25 for housing an electric heating element, of any well-understood construction and indicated at 26. An air inlet opening 21 is formed in the baille 23 and a relatively large throat 28 is provided at the bottom of the baffle for the discharge of the heated, humid air from the chamber 24. A plurality of openings 29 may be provided in the recessed portion of the baffle 23 for the ingress of air to the cove 25 and the heating chamber 24. Admission of air from the ambient atmosphere to the housing I0 is afforded by a plurality of louvred openings 3! arranged in one of the walls of the housing It, such as, for example, the front wall H.

The basket I! and its shaft iii are rotated at a speed of, for example, 50 R. P. M. by means of a sheave 32 fixed to the shaft i6 and belted, as shown at 33, to a pulley 34 driven by an electric motor 35. The motor 35 also drives a blower 36 having a discharge port 31 extending through the housing w for the delivery of humid air to the ambient atmosphere. The inlet eye of the blower 36 is shown at 38 and communicates with a chamber 39 formed in the bottom of' the housing Ill and communicating with the throat 28. Preferably a lint trap 4| formed, for example, of a fiat sheet of screen cloth, is disposed between the throat 28 and chamber 39 for the gathering of lint which may accumulateduring the tumbling of fabrics in the basket. Preferably the lint trap 4| is removable, by means of a handle 42, through a suitable opening in the front wall ll of the casing for the periodic cleaning of the lint trap.

As described hereinafter, the operation of the heater 26 and the motor 35 is controlled by a timer, generally indicated at 44 and carried by an upper portion of the housing Ill; the timer 44 having a manually-operated knob for initiating operation of the timer and accessible at the front of the cabinet. The timer 44 will be described more in detail hereinafter. Energization of the heater 26 also controlled by a thermostatic switch, generally indicated at 40 and carried by the baflle 23 in a position where it will reflect the temperature of the atmosphere within the drying chamber 24.

According to my invention, the timer 44 conditions the heater 26 for energization accompanied by operation of the motor 35 for a predetermined period of operation of the timer, at the conclusion of which period the heater26 is rendered inactive. The motor 35, however, continues to operate for a second predetermined period of operation of the timer to continue the tumbling of the fabrics and the circulation of air through the chamber 24. It is during the continued operation of the motor 35 that the heat remaining in the chamber 24 subsequent to the deenergization of the heaters 26 is utilized to complete the drying operation, and a concomitant of this operation is that the clothes are cooled to a temperature at which they may be comfortably handled as they are removed from the basket. 7

Reference will now be had particularly to Fig. 3 for a diagrammatic representation of the timer and the electrical circuits between the various electrical translating devices, referred to heretofore. The timer 44 includes three switches 46, 41 and 48, all of which are biased to their open position and actuated to their closed position by respective cams 49, 50 and 5|. The cams 49 to 5|, inclusive, are fixed to a shaft 52 which is rotated at a relatively slow speed by means of a speed-reducing mechanism 53 driven by a timing motor 54. The latter may be of the synchronous type usually employed for driving clocks. The shaft 52 is provided with a knob 55 which may be manually actuated to advance the cams 49 to 5|, inclusive, when initiating operation of the timer. A slip clutch 56 is employed to permit rotation of the shaft 52 relative the speed-reducing mechanism 53 during a manual adjustment of the cams, and which also functions to drive the shaft 52 during operation of the timer motor 54. Regardless of whether the shaft 52 is manually actuated or driven by the motor 54, rotation is clockwise as shown by the arrow on the knob 55.

The source of power for the apparatus is defined by line conductors L1 and L2 and a conductor N. These three conductors are usually connected to a three-wire, single phase Edison distribution system wherein the potential across the line conductors L1 and L2 approximates 230 volts, while the potential from either of the line conductors L1 and L2 to the neutral conductor N is approximately 115 volts. As shown, the conductors L1 and L2 are respectively connected to one side of each of the switches 46 and 41, and the conductor L1 is also connected to one side of the switch 48 by means of a conductor 58. The opposite side of the switch 46 is connected, by means of a conductor 59, to one terminal of the heater 26 through a pair of contacts 6| forming a part of the structure of the thermostat 46.

The thermostat 46, which may be of any wellunderstood construction, includes a heat-actuated member, such as a bimetal disc 62, which, when the temperatureof the atmosphere within the heating chamber 24 is below a predetermined value, bridges the contacts 6| for energizing the heater 26. Conversely, when the temperature of the air within the chamber 24 is above a predetermined value, the bimetallic element 62 snaps to the position shown in dotted lines in Fig. 3, for opening the heater circuit at the contacts 6|. In the latter position of the thermostatic element 62, a pair of contacts 63 are bridged for energizing the timer motor 54, further reference to which will be made hereinafter. The opposite terminal 41. From this connection, it will be apparent that the motor 35 operates during the period of time that the switch 41 is closed. It will also be apparent that the main heater 26 is conditioned for energization under control of the thermostat during periods when the switch 46 is closed. From the shape of the cams 49 and 5|], it will be seen that the switch 41 is closed simultaneously with the closing of the switch 46 and that the switch 41 remains closed for a period of time after the switch 46 is opened.

During the heating steps in the drying program, the timer motor is energized during peri ods when the thermostat 46 is satisfied, or, in other words, when the temperature in the chamber 24 is above the value at which the thermostatic disc 62 snaps to its dotted line position. Conversely, when the thermostat 40 is calling for heat, the timer motor 54 is deenergized. As shown, one terminal of the timer motor 54 is connected by a conductor 66 to one contact 63 of the thermostat 46, the opposite contact 63 being connected to the conductor 59. The opposite terminal of the timer motor 54 is connected by means of a conductor 61 to the neutral conductor N. A switch 68 may be interposed in the conductor 61 for manually rendering the timer motor 54 inactive, the purpose of which will be referred to hereinafter. The conductor 66 is also electrically connected by means of a conductor 69 to the movable contact of the cam-operated switch 48. From this connection, it will be apparent that, when the switch 48 is closed towards the conclusion of the heating step in the cycle. the timer motor 54 will be continuously energized regardless of the position of the thermostat 40.

In operating the drier described heretofore, the operator deposits the wet fabrics in the basket l1 and closes the door l3, after which the timer knob 55 and the cams 49 to 5| are moved angularly from the off" position of the timer to the 011" position thereof, which movement is sufficient to close the switches 46 and 41. Accordingly, the heater 26 is energized since the thermostat disc 62 is relatively cool and is, therefore, in the position shown wherein the contacts 6| are bridged. The circuit for energizing the heater 26 includes the line conductor L1, the switch 46, conductor 59, the bridged contacts 6|, heater 26, conductor 64, switch 41 and line conductor L2. The main motor 35 is also energized for tumbling the fabrics and for the circulation of air therethrough by means of a circuit extending from the line conductor L2 and including the switch 41, conductors 64 and 65, main motor 35 and a neutral conductor N. Since the contacts 63 and the switch 48 are open, the timer motor 54 is inactive.

The heat generated by the heater 26 at this time progressively increases the temperature of the drier structure and the fabrics contained therein. During theearly stages of this heating step, the rise in temperature within the chamber 24 is relatively slow as a substantial portion of the energy dissipated by the heater 26 is converted to latent heat of vaporization and a relatively small percentage of the energy dissipated by the heater is converted to sensible heat. As the drying progresses, more energy is converted to sensible heat and less to latent heat so that the of the heater 26 is connected by a conductor 64 7o temperature rise is increased. When the temperato the movable contact of the switch 41.

One terminal of the main motor 35 is directly connected to the neutral conductor N, while the opposite terminal is connected by means of a ture of the chamber 24 is increased to a predetermined high value of, for example, 180 F., the thermostat 46 opens the contacts 6| and closes the contacts 63. Accordingly, the heater 26 is conductor 65 and the conductor 64 to the switch deenergized and operation of the timer is initiated since the timer motor 54 is now energized by means of a circuit including line conductor L1, closed switch 48, conductor 89, the bridged contacts G3, conductor 56, timer motor 54, conductor 61 and the neutral conductor N.

The cams 49 to ii are now rotated clockwise at a relatively low speed. During this operation of the timer, the temperature within the chamber 24 may drop to a predetermined value for example, 160 F., so that the contacts 6| are again bridged for energizing the heater 26. and the contacts 63 are opened, whereupon operation of the timer motor ceases. The heater 26 will be energized and deenergized under control of the thermostat 40 until the timer cams have been advanced suificiently to open the switch 46 whereupon the heater 26 is deenergized for the remainder of the cycle. At this time, the clothes are substantially dry. I Shortly before the opening of the switch 46, the switch 48 is closed to establish a shunt circuit around the contacts 63 for the continuous energization of the timer motor 54. This shunt circuit includes the conductors Ll, 58 and 69. It will be understood that the main motor 35 continues operation after the opening of the switch 48 as its circuit is maintained by the closed switch 41.

During the latter part of the drying cycle or after the heater 26 has been deenergized by the openingof the switch. the continued circulation of air through the chamber 24 completes the drying operation. The stored heat is, utilized for this purpose, and since there is a continuous flow of relatively cool air from the ambient atmosphere, the drier structure is cooled as the fabrics are being dried. After a predetermined period of continuous operation of the timer 8d, the switch 47 is opened by the cam 50. whereupon the main motor 35 is deenergized. Shortly thereafter, the cam opens the switch 48 for de-energizing the timer motor 5%. The apparatus is now in the ofi position, as shown, and the dried fabrics may be removed from the basket.

The steps in the drying cycle recited heretofore obtain whether the load to be dried is heavy or light. However, the total duration of the drying cycle willbe longer with a heavy load, inasmuch as longer periods of energization of the heater are necessary to vaporize the moisture. Conversely, with a light load the periods of en-- ergization of the heater 26 are shorter and the duration of the entire cycle will be relatively short. The wattage of the heater 2d, the amount of air translated through the drying chamber 2d and the speed at which the timer motor 5% ad vances the cams are correlated so that the ma heavy, and when such conditions prevail, it is 8 degree or dampness in the fabrics at the conclusion of the cycle.

Occasionally extremely heavy drying loads are encountered such as, for example. when a pinrality of heavy throw rugs are to be dried or when the amount of molsturein any load is the timer motor. when the load is dried, the

jority of the loads usually dried in apparatus of this kind will require but a single setting of the controlknob 55. If the knob 55 is adjusted to its "on position, as indicated, without any addi tional angular movement of the knob, the fabrics will be thoroughly dried when removed from the drier. The operator may, however, in initiating operation of the apparatus, advance the knob 55 beyond its on position in order to shorten the time that the switch $6 is closed during the heating cycle. Accordingly, when the cycle is terminated thefahrics are damp in order to provide for immediate ironing. The amount of dampness remaining in the fabrics may be selected by the operator when initiating the cycle by advancing the control knob more or less. In this connection. indicia may be provided on the knob 55 to guide the operator in. selecting the operator moves the timer to the "01? position or may advance the timer to the position wherein air circulation only is eflected and then close the switch 68. Accordingly, the load will be cooled during the operation of the timer to its oil position. The switch 68 is so constructed that it is retained in its "011 or o position after having been moved to either one of these positions.

' The drier which I have indicated in Fig. 4 and constituting a second embodiment of the invention is constructed generally along the lines described heretofore, and parts which are common to both are indicated by similar reference numerals. This drier is provided with thermostat, indicated at l l for controlling energization of the heater 2G and constitutes a safety thermostat which prevents overheating of the air in the chamber 2E. The second thermostat i2 reflects the temperature of the discharged air and is preferably located in the chamber 39. As shown in Fig. 5, the thermostat I2 is constructed generally along the lines of the thermostat so, in that it includes a bimetal element 73 which moves from the position shown in the drawing to its dotted line position, in response to a predetermined temperature of, for example, 180 F. This thermostat i2 is, however, of the high differential type and is adapted to move from its dotted line position to the position shown in the drawing, when the temperature of the air has been depressed to a temperature of, for example, F. The thermostat?! may be arranged to open its contacts at a temperature of 185 F. and functions as a safety device which in normal operation remains closed.

As shown in Fig. 5, the thermostatic element 73 bridges contacts M, which'indicates that its temperature is below F. When the temperature or the air in the discharge duct attains 180 F., the element 13 moves to its dotted line position, wherein it bridges contacts 75. The element 73 remains in this dotted line position until the temperature has been depressed to 130 F.

The timer structure associated with Fig. 4 is indicated generally by the numeral id and includes a pairof cams W and it? which are rotated with the shaft 52 by the timer motor 5d through the reduction gearing b3. As in the first embodiment, the shaft 52 may be moved angularly manually by the knob 55 from an ad position to an on position.

The cam E1 in the on position closes a pair of switches 8i and 82 and the cam it closes the switch 83. One terminal of the switch BI is connected to the line conductor Li and the other contact of the switch 85 is connected to a ter- 7 mine! of the heater 26 through the thermostat II. The other switch 82 has one of its contacts connected directly to the line conductor In and its second contact connected to the opposite terminal of the heater 26 through the contacts 16. One terminal of the timing motor 58 and one terminal of the main motor 35 are electrically connected by a conductor 84 to the stationary contact of the cam-operated switch 83, the movable contact of which is directly connected to the neutral conductor N. The opposite terminal of the timer motor 54 is connected by means of a conductor 85 to the line conductor Li through the contacts of the thermostat I2. The opposite terminal of the main motor 85 is connected by means of a conductor 86 to the line conductor Lo.

In initiating operation of the drier shown in Figs. 4 and 5, the timer is advanced to its on" position after the damp clothes have been deposited in the basket l'l. Accordingly, the switches 8|, 82 and 83 are closed. Closure of the switches 8| and 82 energizes the heater 26, it being understood at this time that the therm stat 12 is relatively cool or at room temperature. The closure of the switch 83 energizes the main motor which operates, as described heretofore, to tumble the fabrics in the basket and to circulate air through the drying chamber 24. Operation of the heater 28 increases the temperature within the chamber 24, the increase being relatively slow at the beginning of the heating cycle because 01 the large amount of water to be evaporated. As the drying progresses, the temperature increases rapidly as described heretofore. During this drying operation, the. timer motor 54 is inactive. When the temperature of the air in the discharge duct attains 180 F., indicating the fabrics are substantially dry, the thermostatic element I3 moves to its dotted line position for deenergizing the heater 26 and for energizing the timer motor 54. The latter thendrives the cams l1 and 18.

When drying a heavy load, the heater 26 will be energized for a relatively long period of time, during which a relatively large amount of heat is stored in the fabrics and the drier structure. Accordingly, the thermostat I2 being of the wide difierential type, a relatively long period of time elapses between the opening of the thermostat contacts 24 and the reclosing thereof. With a light load, the heating of the fabrics is more rapid and less heat is stored in the drier structure that when the load is heavy. Accordingly, the cooling of the thermostat is more rapid and it recloses its contacts I4 in a shorter period of time than when the load is heavy.

During operation with a heavy load, the timer operates to open the switches 8|, 82 and 83 prior to the reclosing of the contacts 14 by the thermostatic element 13 because, as pointed out heretofore, the large amount of heat stored in the drier structure prevents early reclosing of the thermostatic switch 12. Accordingly, the heater 26 may be energized only once during the drying cycle.

From the foregoing description, it will be apparent that I have provided improved drying apparatus wherein the material being treated is dried and then cooled for handling, a substantial portion of the heat remaining in the material and the drier structure subsequent to terminating operation of the heater being utilized to complete the drying operation. The various steps in the drying cycle are automatically efiected by a master control or timer which may be adjusted to vary the degree of drying, the desired degree being obtained regardless of the weight of the load being dried. This operation is obtained automatically by varying the duration of the period of time that the heating means is conditioned for-operation in response to the load on the drying apparatus. The cooling step in the cycle is carried out during a fixed period of time.

What I claim is:

1. In drying apparatus, the combination of means defining a drying chamber for the material to be dried, means for circulating air through said chamber, means for heating the air, control means for the air heating and air circulating means adjustable from an inactive position to an active position for initiating operation of the air circulating means and the heating means, a timer for actuating the control means to its inactive position, said control means being effective to terminate operation of the heating means after a predetermined period of operation of the timer and to terminate operation of the air circulating means after a second longer period of operation of the timer, means responsi've to a predetermined low temperature of the heated air for energizing the heating means and responsive to a predetermined high temperature a of the heated air for deenergizing the heating means during periods of operation of the latter, and means responsive to predetermined low and high temperatures of the heated air for, respectively, terminating and initiating operation of the timer.

2. The combination as claimed in claim 1, meluding means rendered eifective after a precontrolling energization of said 'air circulating means and said air heating means, respectiveLv, means for closing said first and second switches when initiating a drying cycle, thermostatic means controlling energization of said heating means, said thermostatic means eifectirig the energization of the heating means in response to a predetermined low temperature of said air and deenergization of the heating means in response to a predetermined high temperature of said air, motor-driven timing means for actuating said second switch to its open position after a predetermined period of operation of the timing means and actuating the first switch to its open position after a predetermined, longer period of operation of the timing means, means actuated by said thermostatic means for energizing the 9 timing means during periods when the heatin means is deenergized and for deenergizing the timing means during periods when the heating means is energized, and switch means for energizing the timing means independently of the thermostatic means after a predetermined period of operation of the timing means, said switch means being eilective to deenergize the timing means at the conclusion of the drying cycle.

5. The combination as claimed in claim 4, including a manually-actuated switch controlling energization of the timing means and movable, at will, to an open position for terminating operation of the timing means.

6. In drying apparatus, the combination of means, defining a drying chamber for the material to be dried, means for circulating air through said chamber, means for heating the air, first and second switching means respectively controlling operation of the air circulating and the air heating means, motor driven timing means actuating the first and second switching means for cycling the air heating and air circulating means in a predetermined program, a thermostat movable to first and second positions in response, respectively, to predetermined high and low temperatures of the circulated air, a switch actuated HAROLD F. GORSUCH.

nnrnnnncns crrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,675,160 Carroll June 26, 1928 2,161,847 Blodgett June 13, 1939 2,351,326 Ergbuth June 13, 1944 2,363,467 Strobridge Nov. 21, 1944 2,398,880 'Broglie Apr. 23, 1946

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