US3023514A - Clothes dryer - Google Patents

Description

G. M. GIBSON CLOTHES DRYER March 6, 1962 l6 Sheets-Sheet 1 Filed July 2, 1956' IN VEN TOR.

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March 6, 1962 INVEIYTOR: Gear 6% GCZDSOfL MEQ/ March 6, 1962 G. M. GIBSON CLOTHES DRYER l6 Shets-Sheet 16 Filed July 2, 1956 fl/ 0% 0 m g x mm m w w y W 0 2 Q 2 6B 6 G r an United States Patent-O 3,023,514 CLOTHES DRYER I George M. Gibson, G. M. Gibson Corporation, Bellevue, Iowa Filed July 2, 1956, Ser. No. 595,226 28 Claims. (Cl. 34-57) This invention relates to a clothes dryer providing a new method for removing moisture from a quantity of wet garments and which provides an apparatus for carrying out the operative functions of the method employed.

Existing clothes dryers are almost all based on a rotating drum or cylinder principle, using cycle control means to vary the drying method according to desires or to various conditions of operation. But all dryers of this character are excessively and objectionably hard on garments specifically due to frictional Wear. Some use wire basket drums, others use perforated drums and similar interrupted or apertured type surface designs for the drums or cylinders which all add to the frictional and abrasive wear, so to speak, of the garments that are subjected to the turning action of the revolving units in carrying out the drying action in devices of this kind.

Other objectionablefeatures of known clothes dryers are the outgrowth of the numerous and complicated control mechanisms employed for cyclic manipulation of the dryers. Furthermore, excessively large heating elements are employed for lessening the drying time. These elements are expensive, power consuming and must be controlled carefully to prevent overheating and at the very best prove to be inetlicient for the results actually obtained.

It must also be considered that all rotary drum and cylinder dryers need large substantial bearings and stout supports plus drives and belting or other means of speed reduction and control.

I One of the objects of the present invention is to provide a simple, inexpensive light weight and comparatively small cabinet clothes dryer that operates on a different clothes drying principle and one that eiiectively removes water from garments over a very short time interval under eflicie-nt heat control operation.

Another object of this invention is to eliminate excess wear on garments with negligible lint removal or accumu lation. Substantially all Well known and popular clothes dryers must make lint disposal provisions, the excessive lint being due primarily to excess wear and abuse to the garments. No lint catching units or drawers are necessary with the dryer of this new construction and operatron.

A further object of the invention is to provide an air jet principle to act upon the clothes with a unidirectional air flow, the air actually floating the clothes, so to speak, with the incorporation of a heating element of fixed capacity that is used, as is, throughout the drying cycle.

Another object of the method of drying clothes is to dispose a load of wash in a given air stream area and to force air through the load in one direction, taking in an air supply from the ambient air and again discharging it into the ambient air after passing through the clothes load. As a variation to this method, the air may be recirculated in part to again act upon the clothes and more than once.

A still further object of this invention is to provide a selective cyclic control to vary the drying action, as for example, over a range from damp dry to fully dry. In this respect, the control is a thermostatic switch arrangement that is temperature responsive to a given selected degree of clothes dryness or wetness as the case may be and wherein the control starts and stops the complete cycle as selected. The shut-off is automatic. This control "ice starts and stops the air jet mechanism and the heating element for the clothes drying air.

Another object of the invention is to provide a vertically arranged clothes receiving chamber with a tempered air source, blower and heating element at the bottom and an exhaust at the top, and to provide a thermostatic circuit control switch at a given height within or in a position of communication with said chamber and wherein the thermostat is directly thermally responsive to the temperature of the air attained in the cabinet at the thermostat location and preferably in a zone near and above the garment or clothes mass in the drying chamber.

The drying action on the wet clothes in the cabinet produces a situation wherein the cabinet walls and clothing remain relatively cool from the start of the drying cycle as air is forced into and through the clothes even with the addition of heat from the heating element. This is due to cooling by evaporation. Experiments have shown that this cooling phenomenon prevails during the portion of the cycle wherein the greater amounts of water are initially removed or extracted from the garments with the moisture removal tapering oil during the cycle of operation. As the drying progresses, the lower portions of the walls of the chamber, and correspondingly the garments in the bottom of the chamber, become gradually warmer and hotter. As the water removal process continues, the clothes and the chamber walls become progressively warmer or heated upwardly in relation to the blower and heater location until all the clothes attain a given generally uniform temperature which is also evidenced by warmer chamber walls surrounding the vertical core of the clothes mass or batch. When the entire garment group becomes so heated or warmed the clothing has reached a given stage of dryness and as determined by the setting or selection of the thermostatic switch operation, the drying cycle circuit is automatically interrupted by this instrument which by its location in the xhaust air stream in the dryer then shuts oil the blower and heater to conclude the water removal interval.

By setting the thermostat at selected shutoff temperatures, it is possible to retain a given minimum amount of moisture in the clothing or else to completely dry the batch all according to the operators desires or as may be governed by subsequent clothes disposal or handling as to whether the clothes are to be ironed or are just to be put away in dry condititon; or in conformance with any other condition of use having a direct bearing on a given moisture content in clothing or other articles sub-' mitted to the dryer.

As another object, the present invention contemplates the incorporation of a clock actuated timer in the control circuit of the clothes dryer to provide for a predetermined on and off period of operation. Under such a time control, the regulation of the drying function period may be accomplished within reasonably accurate limits. The blower creates a constant air supply and the heating element is made to function at full capacity transmission of energy so that no particular variance should normally prevail with these operational units. that may be encountered might prevail in the placement of the individual pieces of clothing and to some extent in the respective moisture absorption of these various garments. Another variable factor may be experienced by a marked change in the temperature of the ambient air that is drawn into the drying cabinet.

On the whole, the last two variables are normally of no great concern since the deviations will generally average out. Furthermore, with a strong constant capacity blower and a concerted constant heat input, the drying etficiency will be predicated primarily on these dominant and important factors which will readily overshadow the The only variance 1.5 comparatively small variations noted. Thus, a good timer will provide fairly consistent repeated results under appropriately selected cyclic periods.

Another object of the invention is to provide a simple method for drying articles in a tunnelled air stream and to provide means to control the behavior of such articles in said air stream to obtain a predominantly efficient drying action under such conditions of operation. This method is supplemented by the addition of a source of heat to induce better moisture absorption and dissipation.

Other objects and advantages inherently residing in the clothes dryer of the present design and invention and in the method of drying articles as herein set forth and defined shall hereinafter become apparent from the following detailed description having reference to the accompanying drawings forming a part of this specification.

In the drawings:

FIG. 1 is a vertical cross sectional view through the cabinet of a clothes dryer embodying the principles of the present invention therein, this section being taken in a transverse plane side to side of the machine and looking rearwardly from the forward interior portion of the machine and with the operating mechanisms there in generally shown in elevation;

FIG. 2 is a transverse plan sectional view through the clothes dryer as taken substantially along the plane of the line 2-2 in FIG. 1 and looking downwardly in the direction of the arrows;

FIG. 3 is another transverse plan sectional view taken through the clothes drying machine substantially along the plane of the line 3-3 in FIG. 1;

FIG. 4 is a further plan sectional view taken through the clothes drying machine along the plane of the line 4-4 in FIG. 1;

FIG. 5 is a fragmentary vertical cross sectional view taken through the lower portion of the machine and on an enlarged scale showing the operating mechanisms in section and as viewed substantially along the plane of the line 5-5 shown in FIG. 2;

FIG. 6 is a detailed vertical cross sectional view of the upper rear wall portion of the machine cabinet including the exhaust vent and the thermo-electric circuit switch mechanism all as viewed substantially along the plane of the line 6-6 in FIG. 1;

FIG. 7 is a sectional view analogous to FIG. 6, but showing a regulatory timing mechanism in the electrical operating circuit in place of the thermo-electric switch;

FIG. 8 is a diagrammatic circuit layout for the clothes dryer using the thermo-electric switch of FIG. 6 therein;

FIG. 9 is a vertical cross sectional view taken through the dryer cabinet and looking rearwardlv thereof to diagrammatically illustrate the method of loading;

FIGS. 10 and 11 are transverse sectional views taken on lines 10-10 and 11-11 respectively in FIG. 9;

FIGS. 12 to 17 inclusive are views showing the manner of handling individual articles of clothing for the machine loading process;

FIG. 18 is a fragmentary vertical sectional view on the order of FIG. 9 illustrating the bottom portion of the machine in operation;

FIG. 19 is a fragmentary vertical sectional and detail view showing a modified arrangement of the clothes dryer mechanisms;

FIG. 20 is a plan view of the impeller unit per se as viewed along the line 20-20 in FIG. 19;

FIG. 21 is a fragmentary vertical sectional view as seen along the plane of the line 21-21 in FIG. 19;

FIG. 22 is a vertical cross sectional view taken along the line 22-22 in FIG. 23 illustrating another modified arrangement of the eatures of the clothes dryer;

FIG. 23 is a horizontal cross sectional view taken along the line 23-23 in FIG. 22;

FIG. 24 is a fragmentary sectional detail view of a swingable rack unit as seen along the line 24-24 in FIG. 22;

FIG. 25 is a plan view of the swingable rack per se;

FIG. 26 is still another vertical cross sectional view of a dryer illustrating certain other modifications in design of the dryer structure including a double walled cabinet;

FIG. 27 is a cross sectional view taken horizontally and in the plane of the line 27-27 in FIG. 26;

FIG. 28 is a fragmentary plan view of the FIG. 26 dryer;

FIG. 29 illustrates the lower portion of one other form of clothes dryer accommodating a high output heating coil and blower-motor arrangement as seen in vertical section;

FIG. 39 is a transverse horizontal cross sectional view taken along the plane of the line 30-30 in FIG. 29; and

FIG. 31 generally illustrates one commercial form of snap action set and thermostatic release electric switch that may be employed for circuit control in the dryers described.

Now, with more particular reference to FIGS. 1 to 8',- the clothes dryer of the present invention consists of an upright machine providing a vertically arranged cabinet I mounted upon suitable casters 2, the cabinet 1 having an open bottom 3 and an open top 4 with a suitable lid or cover 5 hinged at 6 to one cabinet wall 7 to be swung from a vertically determined clothes loading position substantially as shown in broken lines in FIG. 6 to a cabinet closing position as best illustrated in full lines in FIGS. 1 and 6.

Wall 7 is here considered as the rear wall of cabinet 1, with walls 8 and 9 providing the opposite side walls thereof and wall 14 providing the front wall of the machine. As best seen in FIGS. 2, 3 and 4, the cabinet is generally rectangular in cross section and the straight walls 7 to 10 are adjacently joined by the respective vertical curved corner sections 11, 12, 13 and 14 to prevent sharp cabinet corner cavities or formations and at the same time providing a large capacity clothes carrying cabinet for the purposes herein described.

The operative clothes drying or moisture removing mechanisms of the machine are assembled and situated at the bottom of the cabinet and preferably just upwardly of or inwardly of the cabinet open bottom 3. The main operating units of this bottom mechanism assembly 15 consist of a motor 16, an air impeller or fan 17 and a. heating apparatus 18. The divisional cavity arrange-- ment providing a continuous air flow path into and upwardly within the cabinet 1 primarily consists of an annular air inlet chamber 19 receiving ambient air through the opening 3 of the cabinet bottom, a filtered air inlet chamber 20 surrounding and including most of the motor 16 and an upwardly opening annular trough air exhaust chamber 21 that partially houses and surrounds the impeller 17 and also the upper portion of the motor 16.

This entire assembly 15 is carried upon the cabinet as a composite unit by a simple and unique combination of baffle and division wall structures that together form the connected and contiguous air chambers that guide and direct the air flow in a path into the cabinet under the direct creation and control of the revolving impeller 17 when actuated by the motor 16, the air tunnelling through the entire area of the cabinet.

The construction of the assembly 15 includes a base plate 22 welded or otherwise secured to the upper side of a strut or cross brace 23 which is in the form of an inverted channel made with flattened ends 24 and 25 which seat upon the inturned cabinet portions 26 and 27 respectively of the cabinet terminal flange 28 that encircles and outlines the cabinet opening 3. Suitable nut and bolt fastening units 29 secure the strut ends to opposite portions of the cabinet flange 28.

A plurality of resilient mountings 30 including the motor assembly bolts 31, spacing nuts 32, spaced rubber bushings 33 and 34, and securing nuts 35 are employed to attach the motor 16 to the case plate 22. The bolts 31 \d pass through suitable clearance apertures provided in plate 22 so that no supported metal directly touches the plate 22 while the rubber bushings act as the main supporting reactionary feet for the motor 16 and to counteract noise and vibration transmittal to the cabinet structure proper.

The resilient motor mountings 30 include a plurality of brackets 36 that support an annular ring 37 to which the heater mountings 38 are secured. Mountings 38 include the insulating bushings 39 that carry the resistance coil 40 of the heating apparatus 18. This described heating 'coil supporting arrangement disposes the resistance coil 40 annularly about the motor and spaced therefrom, while placing the coil in the air exit or exhaust part of the filtered air inlet chamber 19 and just beneath the impeller or fan 17.

Assembly 15 further provides an annular diaphragm or shroud 41 arranged in vertically spaced relation with respect to the base plate 22. It should be observed that the base plate 22 horizontally occupies the central cabinet area and that the shroud 41 covers or occupies the balance of the horizontal cross sectional area of the cabinet, although both such baffle units are vertically spaced to provide an annular air inlet communication space between the respective air inlet chambers 19 and 20.

The shroud is vertically supported from the base plate 22 by means of a plurality of legs 42 having radially inwardly formed feet 43 welded or otherwise secured to plate 22 and also having radially outwardly formed feet 44 that are welded or otherwise suitably fastened to the bottom of the shroud 41. Shroud 41 is made with a central air intake opening 45 provided in the flat bottom 46 thereon which is contiguous with the upsweep or upcurved peripheral impeller encircling rim 47 that terminates in an upper horizontal shelf or ledge 48 shaped to fit the cabinet interior area as outlined by the cabinet walls. Thus, with base plate 22 rigidly secured and supported upon the bottom cabinet flange 28 by means of the supporting channel strut 23 and by the provision of the supporting and connecting legs 42 carrying the shroud which neatly fits the cabinet, this entire assembly plus the motor and fan or impeller are all oriented and sup ported in well stabilized relation within the cabinet and adjacent the bottom air entry opening 3 in the cabinet 1.

A suitable replaceable air filter 49 of circular form and of a height to reach from the shroud 41 to the base plate 22 is assembled about the plurality of legs 36 and functions to remove dust and airborne foreign matter from the air that is drawn into the cabinet and directed against and through garments or articles of clothing that are in the tunnel area of the cabinet for moisture removal.

The fan or blower impeller 17 of the assembly 15 is carried in horizontal relation partially nested within the annular shroud 41 by means of a hub 50 that is pin connected at 51 with the vertically extended shaft 52 of motor 16. Impeller 17 is a composite sheet metal assembly of an upper disc or web 53 to which are welded or attached a plurality of arcuate vanes 54 that are well shown in FIG. 3. Each vane 54 is a channel piece providing an air impelling vane wall 55 terminating with upper and lower vane attaching flanges 56 and 57 as shown in FIGS. 3 and 5. The impeller vanes 54 are propelled in a clockwise direction by the motor as viewed in FIG. 3, with the larger body portions of the vanes operating in a path disposed radially outwardly of the opening 45 and in the annular shroud 41 with the radially inner ends of the vanes operating in vertical alignment with the outer annular portion of chamber 20 but thereabove.

The impeller is the operating instrumentality that draws in ambinet air through the cabinet bottom 3 into chamber 15 through the filter 49 into chamber 20 where heat is absorbed from both the heating apparatus 18 and from the motor 16 and then through opening 45 into the im- 6, peller shroud 41 for both radial and upward discharge in large volume quantities under the high speed rotation of the motor. A motor speed of approximately 3000 rpm. has been found quite satisfactory under average operating conditions.

The top or uppermost member of the assembly 15 is an apertured clothes or garment supporting unit 58 that is best illustrated in FIGS. 1, 2 and 5. This supporting unit 58 comprises a dome shaped screen 59 having a central inwardly dished screen section 60. The lower part of the dome portion 59 of the supporting unit 58 is surrounded by a shelf or horizontal table section 61 that conforms with the contour of the cabinet as best seen in FIG. 2. The shelf section 61 of the screen terminates with a vertically arranged peripheral supporting flange 62 to space the shelf or table section 61 in a given relation above the shelf or ledge 48 of the shroud.

To reenforce the screen unit 58 and for the support of heavy wet clothing or garments, a band 63 having a lapped edge 64 is supported on a plurality of channel iron stock legs 65 that are welded or otherwise secured to the outer face of the band 63 and radiate therefrom as best shown in FIGS. 2 and 3 into positions to bisect the curved corner portions of the cabinet 1. Each leg 65 has a foot 66 that rests upon the shelf 48 of the shroud 41 and an arcuate upright 67 that follows the contour of the screen crown 59 to meet the band 63. As will be observed, band 63 lies coincident with the circular junction 68 of the crown 5? and the contiguous adjacent periphery of the dished section 60, keeping the support at this point of the screen, which is the highest portion of unit 58.

' A clothes control arrangement in the form of a rack 65 is adjustably supported intermediate the vertical height of the cabinet. This arrangement functions as a garment stabilizing means with more particular reference to its action in cooperation with smaller clothes loads per se or to function in the same capacity for greater clothes loads that are placed or positioned within the cabinet both below and/or above the rack location. The rack provides a maximum rise position for the clothing or garments that are placed and carried upon the apertured unit or screen 58. Not only does the rack determine the maximum rise limit of the cabinet clothing core, but the rack counteracts clothing disarrangement and tilt so that the blower air supply as created by the impeller will, for the greater part, pass into and through the garments for optimum drying efficiency. Greater moisture absorp-- tion results in direct blower air clothes penetration. By keeping the garments in piston fashion in cabinet choking positions and holding them so arranged, the drying cycle is held to a minimum and better results are obtained through a substantial automatic flufling of the garments from good and complete air penetration.

Rack 69 is made from rod or bar stock formed into a rectangular frame having a front bar 70, side bars 71 and 72 and aligned rear bar ends 73 and 74 which terminate in Vertically arranged parallel guide bars 75 and 7 6. A short length of bar 77 is connected with one of the bar ends 73 or 74 and extends across the central gap at the rear of the frame that lies intermediate the guide bars 75 and 76. By having the aligned rear bar ends free to move relatively to each other, spring in the frame will act upon the guide bars 75 and 76 to frictionally act upon the bar receiving frame mounting means 78 to hold the rack in a vertically adjusted position.

The mounting means 78 is constructed as a bracket 79 secured to the cabinet wall 7 by welding, etc., and this bracket provides spaced side wings 80 and 81 which each terminate in reentrant loops 82 and 83 to form Vertical sleeve guide members to slidably receive the guide rod portions of the frame that were above described as the guide bars 75 and 76. Preferably pins 84 and 85 or other stop means are connected with the upper ends of the aosasm guide bars to prevent complete withdrawal of the rack 69 in a downward direction.

As seen in FIG. 2, the rack 69 is made in the form of the rectangular open centered frame and is spaced inwardly and away from the cabinet walls but generally following the surface contour thereof. Additionally, cross rods or links 86 and 87 are provided with eyelet ends and 89 respectively, which eyelet ends are slidably mounted on the frame side bars 71 and 72. When the rack is in its operative position to coact with the clothes, the cross rods are normally located in the positions shown in FIG. 2. When loading or unloading the machine, the cross rods may be moved toward the ends of the rack, either to t1 e front or rear thereof, or both to the front or both to the rear, leaving a clear open centered rack for loading purposes.

The cabinet may further include a shelf such as 9% in FIG. 6 on one or more sides thereof or which can be made to encircle the entire open end 4 of the cabinet to provide, in either case, another clothes rise limiting means at a higher elevation than the rack to prevent excessive upward movement or disarrangernent of the garments under the action of the updraft air current that acts upon the clothes load in the cabinet. Normally, this upper shelf structure is not too critical, but it may be here mentioned that more than one rack such as 79 may also be employed in different elevations in the cabinet if desired. Then also, these racks do not compress or seat upon the clothes carried thereunder. They allow a certain amount of freedom of action of the respective garments of the load within the cabinet with a limited amount of shifting of the garments in each layer which has been found advantageous in obtaining efficient and controlled drying results. However, as explained previously, the racks do keep the garments generally in wall to wall relation and in cabinet choking positions as previously pointed out.

It should also be apparent that the shape of the apertured unit or screen 58 further contributes to the best clothes arrangement by keeping the various pieces of clothing in positions to accept and permit air penetration for the drying function to be carried to a quick and eflicicnt conclusion.

Referring now to MG. 6, the cabinet is provided with one or more exhaust openings or ports 91 located im mediately below the lid or cover 5. A suitable shield 92 protects the openings 91 from becoming covered by small articles such as handkerchiefs or clothing parts. This shield is secured to the cabinet and is formed as shown with open sides for air how out of the cabinet and ports. it has been found that under certain conditions of operation that the lid or cover 5 may also lift under air pressure to let some of the moisture laden air out of the cabinet top opening 4.

The power supply and circuit control mechanisms may best be described with reference to FIGS. 1, 5, 6 and 8. A power service cord it with a conventional plug )4 may be connected with the usual house line circuit through a wall socket or the like to bring the supply current through wire 95 to a thermo-electric switch 5 that is confined within a moisture sealed housing )7. Switch 96 includes a suitable thermal responsive make and/or break contact 98 which may be regulated to operate and open the circuit at different selected temperatures as by means of an adjustment knob Any conventional thermo-electric switch of this character will function when used in the described location as best illustrated in FIGS. 1 and 6. in general, the switch is of the push button set snap action type that closes the circuit with one of the contacts being bimetallic and heat responsive to break the circuit when subjected to a given temperature.

Through switch 96, the supply current is conducted by wire ltltl into and through a conduit fill that leads out of an opening in cabinet wall 7 and through a protective housing 183 attached to the cabinet wall '2'.

(ill

ii Conduit Edi reenters the cabinet through an opening 164 and leads to a grommet arrangement in base plate 22 and into the filtered air inlet chamber 25 Wire tilt is then branched or divided with one lead 166 going to motor and the other lead i going to one end of the resistance coil it) as best shown in FIGS. 3 and 5.

Return circuit wires or leads and 109 come from the motor in and from the other end of the coil 4% (see PEG. 3) and join the wire 38.6 that reenters the conduit 1 1 and leads back upwardly to the power cord 93 as best sh vn in 6. The same general arrangement is also well illustrated more diagrammatically in FIG. 8.

It has been discovered and determined that the drying operation of a batch or load of clothes follows a predetermined pattern of both moisture and heat dissipation. At the start of the drying cycle, the entire cabinet rcnialns fairly cool and as the cycle progresses, the cabinet warms up from the bottom with the warmth travelling upwardly the clothes begin to lose their excess water. This indicates that the moisture removal brings about a cooling by evaporation even with the introduction of heat into the air stream.

This action further revealed the fact that when the entire clothes load become warm that a substantial predetcrrnined dryness had been attained, as for example, a damp dry stage. By continuing the drying cycle the clothes could be entirely dried as they become still warmer.

by taking advantage of this particular phenomenon and locating the illfii'tZlO-ClfiCiliC switch 96 as described in a region above the normal top level of the clothes load, this switch after it is button actuated to On position, will be in a heat responsive state to shut off when a predetermined temperature is attained in the zone surrounding the switch location. By using an adjustable means to vary the actuation of the bimetallic switch contact so as to operate at a given selected temperature, the degree of clothes dryness can also be regulated thereby to suit the desires of the operator.

To make the thermo-electric switch more sensitive to the attainment of a given temperature, the housing 103 on the back wall of the cabinet is made considerably larger than necessary to carry the conduit llll so as to function in the capacity of an air conductor or flue acting as a chimney whereby to bring cabinet warmed air from the lower portion or the cabinet into the housing 97 and to the bimetallic switch part for preheating purposes. This cuts down the lag in the final interval of heat transmission to the housing 97 and to the switch operating parts making the switch react quicker to the cabinet clothes load temperatures.

The warm air circulation into the thermo-clcctric switch housing 97 is preferably kept in motion by suitably located bleed openings 111 formed in the cabinet wall 7 in a position to be covered by the housing 97. An adjustable apertured slide plate 112 can also be employed in cooperation with the bleed openings to provide a regulatory means for suitable variation of the amount of air that may be bled out of the tube or conduit 103 and out of the housing 97.

Referring to FIG. '7, this illustrates the use of a timer in place of the thermoelectric switch arrangement just described. it is understandable that certain clothes loads will dry in this machine to a reasonably determinable amount or" dryness over a given period of machine operation. Repetition of like loads for like periods, should therefore, give fairly consistent results. For this reason, a clock timer 1.2.3 of a conventional type with a time regulating knob 114 may be placed into the same machine circuit for selecting predetermined time cycles for drying operation. The present machine has constant blower airflow and constant heat introduction is, therefore, well suited for a clock timer cycle control.

Some variation in opei tion may occur in the machine loading of the machine by the operator, but with a little

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