US3373501A - Process of drying fabrics in a rotatable receptacle - Google Patents

Description

March 19, 1968 J. c. WORST 3,373,501

PROCESS OF DRYING FABRICS IN A ROTATABLE RECEPTACLE Filed Dec. 215, 1966 2 Sheets-Sheet l INVENTOR. TQSEPH C. W0 RST ms ATTORNEY March 19, 1968 J. c. WORST 3,373,501

' PROCESS OF DRYING FABRICS IN A ROTATABLE'RECEPTACLE Filed Dec. 23-, 1966 '2 Sheets-Sheet 2 59 46 ea 9 O 88 a2 E as 25 55 7 F'lG.3

ACCELERATE TO PLASTER SPEED ROTATE AT PLASTER SPEED AND HEAT REDUCE TO TUMBLE SPEED ROTATE AT TUMBLE SPEED DRUM TWO SPEED CLUTCH I F G 4 INVENTOR. :rosEPH c. WORST MW HEATER H s ATTORNEY SPEED CONTROL United States Patent ()fiiee 3,373,501 PROCESS OF DRYING FABRICS IN A RQTATABLE RECEPTACLE Joseph C. Worst, Louisville, Ky., assignor to General Electric Company, a corporation of New York Continuation-impart of application Ser'. No. 418,239,

Dec. 14, 1964. This application Dec. 23, 1966, Ser. No.

6 Claims. (Cl. 34-8) ABSTRACT OF THE DISCLOSURE A process of drying fabrics in a rotatable receptacle wherein the receptacle is rotated at plaster speed while heat is supplied until the moisture remaining in the fab rics is reduced to approximately the critical moisture content of the fabrics. Thereafter the speed of the receptacle may be reduced to tumble speed for the remainder of the drying process. Also, thereafter, the speed of the receptacle may be alternated between plaster speed and tumble speed for the remainder of the drying process.

This application is a continuation-in-part of my earlier filed application, Ser. No. 418,239, filed Dec. 14, 1964, now abandoned, and assigned to the same :assignee as the present invention.

This invention relates to an improved process of drying fabrics.

Domestic clothes dryers have greatly improved the life of housewives by eliminating much of the drudgery of wash day. However, they have not been of as great a benefit as possible because not all fabrics can be dried satisfactorily in presently available dryers.

Present day dryers utilize a method of drying in which the fabrics to be dried are tumbled in a drum-like container while hot air is forced through the fabrics to evaporate the moisture. Such a method is generally very satisfactory; however, certain fabrics cannot be successfully dried in this manner. For example animal fibers having surface scales, such as wool, cashmere, mohair and camel hair (among others) will shrink and have balls of fuzz formed on their surface (felting) when dried by this method. I have found that the shrinkage and felting is caused by the various portions of the fabrics being flexed and rubbed against other fabric portions when the fabrics are very wet.

It is an object of this invention to provide an improved process of drying fabrics.

It is another object of this invention to provide an improved process of drying fabrics which prevents shrinkage and felting.

In carrying out my invention in one form thereof, I provide a process of drying fabrics in which the fabrics are placed in a rotatable receptacle or drum, the receptacle is accelerated to a speed sufiicient to plaster or just hold the fabrics against the receptacle wall, the receptacle is then rotated at this plaster speed while heat is supplied to the receptacle to evaporate most of the moisture from the fabrics, then the speed is reduced and the receptacle is rotated at a speed to cause the fabrics to tumble within the receptacle for the remainder of the drying process.

My invention may be better understood by reference to the following description taken in conjunction with the accompanying drawings.

In the drawings:

FIGURE 1 is a side elevational view of a clothes dryer for performing my improved process, the view being partly broken away and partly sectionalized to illustrate details;

3,373,5tll

Patented Mar. 19, 1968 FIGURE 2 is a schematic illustration of a control gircuit appropriate for use in the machine of FIGURE 1 to effect my improved process, and

FIGURE 3 is a schematic diagram of the steps involved in one embodiment of my improved process.

FIGURE 4 is a partial schematic illustration of a clothes dryer adapted to perform another embodiment of my invention.

Referring now to FIGURE 1 the machine indicated by the numeral 1 is a domestic clothes dryer adapted to carry out my improved process. Dryer 1 is provided in the usual way with a cabinet 2 having a front door 3 to provide access to the interior of the cabinet for loading or unloading clothes. Provided on the top wall 4 of the cabinet 2 is a control panel 5 which may, in the conventional way, include a suitable pushbutton control system mounted in the panel 5. By manual depression of button 6, the machine may be caused to start, and automatically proceed through a cycle of operation. Within cabinet 2, there is provided a clothes tumbling receptable or drum 8 mounted for rotation on a substantially horizontal axis. Drum 8 is substantially cylindrical in shape, having a first cylinderieal wall portion 9, second and third outer wall portions 10 and 11 located respectively adjacent the front and back of the drum, a front wall 12, and a back wall 13. Outer wall portions 9, 10 and 11 are imperfor ate over their entire length so that the outer shell of the basket is imperforate. On the interior surface of the central portion 9 there may be provided a plurality of clothes tumbling ribs 14 so that clothes may be lifted up when the drum rotates, and then tumbled back down to the bottom of the drum.

The front of drum 8 may be rotatably supported within outer casing 2 by suitable idler wheels, one of which is indicated by the numeral 15. These wheels arerotatably secured to the top of a member 16 which extends up from the base 17 of the machine. Wheels 15 are disposed beneath the drum in contact with portion 10 thereof so as to support that portion.

The rear end of the drum 8 receives its support by means of a stub shaft 18 extending from the center of wall 13. Shaft 18 is secured within a bearing 19 formed in a baffle 20 which in turn is rigidly secured to the back wall 21 of cabinet 2 by any suitable means such as, for instance, welding at a number of points 22. With the arrangement shown the basket may rotate on a horizontal axis, with rollers 15 providing the front support and stub shaft 18 within bearing 19 providing the rear support. In order to provide for the flow of a stream of drying air through the clothes drum, the drum is provided with a central aperture 23 in its front Wall 12 and with an opening in the form of a plurality of perforations 24 in its rear wall 13.

As has been stated, baffle member 20 is rigidly secured to rear wall 21 of cabinet 2. Battle member 20 also serves to support heating means 25 which include two electrical resistance heating elements 25a and 25b appropriately insulated from the baffle member. Elements 25a and 25b may be annular in shape so as to be generally coextensive with perforations 24 in drum 8. Bafile member 26 is rigidly secured to the back wall 13 of the drum outside the ring of perforations 24 and within the stationary baffie 20, so that an annular air inlet 27 is in effect formed by bafiles 20 and 26. In this manner a passage is formed for air to enter annular inlet opening 27 between the baffies, pass over the heater 25, and then pass through openings 28 formed in baflle 26 to the interior of drum 8.

The front opening 23 of the drum is substantially closed by means of a stationary bulkhead generally indicated by the numeral 29. Bulkhead 29 is. made up of a number of adjacent members including the inner surface of access door 3, a stationary frame 31 for the door formed as a flange of front wall 32 of the cabinet, the inner surface member 33 of an exhaust duct which is formed by the cooperation of member 33 with the front wall 32 of the cabinet, and an annular flange 34 mounted on frame 31 and on the duct Wall. It will be noted that a suitable clearance is provided between the inner edge of the drum opening 23 and the edge of bulkhead 29 so that there is no rubbing between the drum and bulkhead during rotation of the drum. In order to prevent any substantial air leakage through opening 23 between the interior and exterior of the drum, a suitable ring seal 35, preferably formed of felt-like material is secured to flange 34 in sealing relationship with the exterior surface of drum wall 12.

Front opening 23, in addition to serving as part of the air flow path through the drum, also serves as a means whereby clothes may be loaded into and unloaded from the drum. Door 3, whose inner surface forms part of the bulkhead closing the opening, is mounted on cabinet 2 so that, when the door is Open, clothes may be inserted into or removed from the drum through the door frame. It will be noted that the door includes an outer flat imperforate section 36 and an inwardly extending hollow section 37 mounted on the fiat outer section. Hollow section 37 extends into the door frame 31 when the door is closed. The door surface 30, which comprises part of the combination bulkhead 29, is actually the inner wall of the hollow section.

The air outlet from the drum is provided by a perforated opening 38 formed in the inner wall 30 of hollow door section 37. The bottom wall section of door 3 and the adjacent wall of door frame 31 are provided with aligned openings 39 and 40, opening 40 providing the entrance to the duct 41 formed by the cooperation of member 33 with front wall 32. As shown, a lint trap 42, which may comprise a fine mesh bag, is preferably positioned in the exhaust duct 41 and opening 40, the bag being supported by the door frame 31. Duct 41 leads downwardly to an opening 43 formed in the member 16 which supports wheels 15. Opening 43 constitutes the inlet to a blower member 44 contained within a housing 45 and directly driven by an electric motor 46. The blower draws ambient air in over the heater 25, then through the basket, then through the door 3 and duct 41, and then into the blower. From the blower the air passes through a duct (not shown) out of cabinet 2 so as to be exhausted from the machine.

In addition to driving blower 44, motor 46 constitutes the means for effecting rotation of drum 8. The motor 46 is provided with a shaft 47 which is connected to one side of a governor clutch 48. A belt 49 extends entirely around the cylindrical wall section 9 of drum 8 and around a pulley 50 formed on the side of governor 48 remote from shaft 47. The clutch 48 is of a conventional governor type so that, each time the motor 46 is energized to rotate the drum, the governor is ineffective and the drum rotates at a speed which is determined by the speed of the motor 46. If the governor 48 is subsequently activated it will, in a conventional manner, cause the speed of the drum 8 to be reduced so that the drum will rotate at some predetermined sub-speed. Once the governor has been activated it will continue to cause the drum to rotate at the sub-speed, even though it is sub sequently deactivated, until such time as rotation of motor 46 is halted. Thereafter, when the motor is once again started, it will begin to rotate the drum at full speed.

Activation of clutch 48 is selectively provided by means of a tab 51 which projects from the circumference of the clutch. A cooperating tab 52 is provided on one end of a pivoted arm 53 so that when arm 53 is pivoted about its fulcrum 53a, tab 52 will be moved upwardly so as to engage tab 51 and activate clutch 48. In order to control arm 53, a coil or solenoid 55 is mounted adjacent the end 54 of the arm opposite the tab 52 and the arm 53 is constructed of a magnetic material. Thus, when an electric current flows through solenoid 55, end 54 will be attracted to the solenoid and tab 52 will be moved upward so as to engage tab 51.

Operation of dryer 1 may be controlled by the control system shown in the circuit diagram of FIGURE 2. As shown therein, the entire control system of the machine may be energized across a three-wire power supply system which includes supply conductors 56, 57, and a neutral conductor 58. For domestic use, conductors 56 and 57 will normally be connected across a 220 volt power supply, with 110 volts appearing between the neutral line 58 and each of the conductors, and with the neutral line being at ground voltage. Motor 46, connected between conductors 56 and 58, is a single phase induction type motor having a main winding 59 and a start winding 60, both connected at a common end to a conductor 61. Through a conventional door switch 62 (which is closed when the door 3 is closed and is opened when the door is opened) conductor 61 is connected to conductor 58. Start winding is connected in parallel with main winding 59 under control of a speed responsive device such as that shown at 63, which is schematically shown as being connected to rotor 64 of the motor. The speed responsive device 63 controls a switch 65 which is engageable with either a contact 66 or a contact 67. Switch 65 is engaged with contact 66 when the machine is at rest, and moves into engagement with contact 67 as the motor comes up to speed. It can readily be seen that engagement with contact 66 connects the start winding in parallel with main winding 59, while movement of switch 65 away from this position opens the start winding. Thus, as rotor 64 comes up to speed the start winding becomes de-energized and the motor then continues to run on the main winding 59 alone.

The starting of the motor is provided by a manually operable switch 68 which may, for instance, in the structure of FIGURE 1 be moved to its closed position by depressing the pushbutton 6. Switch 68 connects the motor to supply conductor 56, and is normally biased to the open position. When member 6 is depressed (and assuming the contacts 63 and of switch 71 are closed) energization of the motor is provided, and, within less than a second under normal circumstances, the motor comes up to speed so that switch 65 engages the contact 67. As a result of this movement of the centrifugally operated switch 65, the main winding 59 of motor 46 continues to be energized by a bypass around switch 68 when member 6 is released and switch 68 opens.

Switch 68 and contact switch 67 connect the motor to conductor 56 through contacts 69 and 70 of a switch 71 which also includes a contact 72. A conventional timer motor assembly 73 may be provided in order to control a cam 74 which in turn controls the switch 71; the timer motor, cam and switch provide together a conventional sequence control mechanism. Cam 74 is also movable by rotation of member 6 in the usual way, so that when operation of the machine is desired member 6 may be rotated until cam 74 causes switch 71 to close all three of its contacts. The machine operation is terminated, as will be seen herebelow, when cam 74 has rotated sufficiently to open the contacts of switch 71.

An energizing circuit is completed for heater 25 through the following circuit. Starting at conductor 56, the circuit proceeds through contacts 70 and 72 of switch 71, then through a conductor 75 to a conventional temperature-responsive thermostat 76, a contact 77 and a conductor 78. The other side of heater 25 is connected through a conductor 79 and a switch 80 to conductor 57. It will be noted that switch 80 is controlled by speed responsive member 63. Thus, heater 25 will not be energized unless motor 46 has come up to speed, thus insuring that fabrics in the dryer will not be heated unless the dryer drum is being rotated and air is being forced through the drum.

Another circuit from conductor 56 to heater 25 is completed in the following manner. Starting at conductor 56 the circuit proceeds through contacts 70 and 69 of switch 71, a conductor 81, timer motor 73, a conductor 82 and a dropping resistor 83 to conductor 78.

An energizing circuit for the governor clutch control coil or solenoid 55 is completed in the following manner. Beginning with conductor 56 the circuit proceeds through contacts 70 and 72, conductor 75, switch 76, a contact 84, a conductor 85, a contact 86, and a switch 87 to coil 55. The other side of coil 55 is connected to conductor 58 by a conductor 88. Another energizing circuit for coil 55 is completed from conductor 56 through contacts 70 and 69, conductor 81, a conductor 89, a contact 90, and switch 87 to coil 55. When it is desired to utilize the dryer of FIGURES l and 2 to perform my improved process of drying, the fabrics that it is desired to dry are placed into the drum 8 through door 3 and door 3 is closed, thus closing switch 62. Switch 6 is rotated to cause cam 74 to close contacts 69, 7t? and 72 of switch 71 and to move switch 87 into engagement with contact 86. Then pushbutton 68 is depressed, causing rotor 64 of motor 46 to rotate and, as the motor comes up to speed, switch 65 is moved from engagement with contacts 66 to engagement with contacts 67 and switch 80 is closed.

Since coil 55 is de-energized drum 8 is accelerated by motor 46 to full speed. By choosing a proper relationship between motor 46, drum 8 and pulley 50 the full-speed rotation of drum is caused to be suflicient to plaster or just hold the fabrics against drum wall portions 9, 10 and 11. Thus, the fabrics are not tumbled, which would cause them to be flexed and rubbed against each other. The initial acceleration of the motor and drum causes the fabrics to be evenly distributed throughout the drum.

Temperature responsive switch 76 is of the type such that below a predetermined temperature it is in position to engage contact 77 and above that temperature it moves to engage contact 84, thus at the beginning of dryer operation switch 76 is in engagement with contact 77 so that timer motor 73 is effectively bypassed and heater 25 is energized across supply conduit 56 and 57. At the beginning of the dryer operation most of the energy supplied to the dryer from heater 25 is use-d to evaporate moisture from the fabrics and there is very little rise in the temperature of the air flowing from the dryer. However, as the moisture content of the fabrics drops the temperature of the outlet air rises and temperature-responsive switch 76 is placed so as to sense the temperature of the air flowing out of the drum (as indicated in FIGURE 1). When suflicient moisture has been evaporated from the fabrics in the drum the temperature of the air flowing through the drum will rise to a predetermined level and switch 76 moves away from contact 77 into engagement with contact 84. This causes coil 55 to be energized between conductor 56 and conductor 58 so that arm 53 is pivoted and tab 52 engages tab 51 to activate the governor clutch 48 so that the speed of the drum is reduced. The governor clutch is constructed so as to cause the speed of the drum to be reduced to a level at which the fabrics within the drum will cease to be plastered against the portions 9, 10 and 11 and will be caused to be tumbled by members 14.

At this time heater 25 is connected to conductor 56 through contacts 69 and 70 of switch 71, timer motor 73 and dropping resistor 83. Since the resistance of dropping resistor 83 and motor 73 is much greater than the resistance of the heater 25 substantially all the voltage drop is across the timer motor and dropping resistor, and heater 25 is effectively turned off.

Motor 46 continues to rotate and air is drawn through the drum by blower 44 so that the temperature of the air being withdrawn from the drum drops and temperature responsive switch 76 moves out of engagement with contact 84 and into engagement with contact 77. This again shunts out timer motor 73 so that the timer motor ceases to turn cam 74 and heater 25 is again energized to provide heat to the drum. Switch 76 also causes coil 55 to be de-energized; however, as explained above, governor clutch 48 is of the type that, once activated, it will continue to cause drum 8 to be rotated at the lower speed so long as motor 46 continues to operate. The operation of the dryer will continue with alternate heating and timer motor running until the timer motor has run long enough to turn cam 74 to such a position that it opens contacts 6%, 76 and 72 of switch 71 to completely de-energize the dryer.

For a typical domestic clothes dryer, such as that shown in FIGURE 1, a suitable plaster speed at which the fabrics are plastered or just held against the drum wall would be at a drum speed of about 60 to 70 revolutions per minute, depending on the drum diameter and size of the fabric load in the machine. Such machines normally tumble fabrics by causing the drum to rotate at about 45 to 50 revolutions. A machine will be operating at plaster speed when the speed of the drum is suflicient to just hold the fabrics therein in an annulus against the drum periphery. This results when the centrifugal force exerted on the fabrics is sufficient to overcome the force of gravity and will vary with the drum size. However, the speed in revolutions per minute (r.p.m.) at which the centrifugal force at the surface of the drum equals the force of gravity is expressed by the formula Drum radius in feet and this formula represents about the minimum speed which should be used as the plaster speed in carrying out my invention.

Obviously as fabrics are dried in larger loads some of them will be located closer to the axis of the drum and the speed will have to be increased in order to hold all the fabrics in the annulus. About the largest fabric load a domestic clothes dryer will satisfactorily dry is one in which the volume of fabrics being dried is about 75% of the volume of the drum when the fabrics are dry. When such a load is rotated in the drum in a plastered state, it will occupy about one-half the diameter of the drum. Thus about the maximum plaster speed required for use in carrying out my invention is expressed by the formula Drum radius in feet The particular speed, within the plaster speed range defined by the above given formulae, which is chosen would be determined by the maximum anticipated load. Rotating the drum significantly above the maximum required plaster speed has at least two deleterious effects. As the speed is increased, the centrifugal force exerted on the wet fabrics increases and tends to set wrinkles in the fabrics, which are hard to remove. This centrifugal force also tends to cause the moisture in the fabrics to migrate toward the outer portion of the fabric annulus, particularly at the beginning of the drying operation when the fabrics are quite wet. Since most modern day dryers usually cause the drying air to enter through the rear of the drum rather than around the periphery, the drying time is minimized by causing as little migration as possible.

It will be obvious to those skilled in the art that the plaster speed for just holding fabrics against the drum wall is substantially below centrifugal extraction speed as usually used in the art. Admittedly, if very wet fabrics were rotated in a perforate container in the speed range set forth herein, some small amount of fluid would be extracted; however, such speeds would not produce real centrifugal extraction of an appreciable amount of fluid. For instance a commercially available dryer similar to that shown in FIGURE 1 has a drum radius of about 7 1.055 feet. The plaster speed, as set forth in the above indicated formulae would be between about 52 r.p.m. and about 75 rpm. Commercially known combination washer-dryers having drum sizes in the same order of magnitude generally perform their centrifugal extraction at speeds between about 195 r.p.rn. and about 450 rpm, depending on the unbalance compensation system used. Vertical axis washing machines have a much smaller unbalance problem and, therefore, centrifugally extract at speeds up to about 600 rpm.

Temperature responsive switch 76 may be set to respond to any temperature level desired. 1 have found that shrinkage and felting of fabrics is the result of the fabrics being flexed and rubbed together when the fabrics are saturated with an amount of water which is above what may be termed the critical moisture content. The critical moisture content is that amount of water which will saturate the substance of the fibers without there being any free water on their surface. On the other hand tumbling the fabrics as they approach dryness enhances their fiuffiness and insures more even drying. Thus, it is highly desirable that governor clutch 48 be operated to reduce the speed of rotation of drum 8 from a plaster speed to a tumble speed at the point when the moisture con tent of the fabrics is approximately the critical moisture content. The critical moisture content varies from one fabric to another. However, I have found that the mois ture content most suitable for giving uniformly good results with my improved process is a moisture content of about 30 to 35%. Thus, temperature-responsive switch 76 should be calibrated to move from contact 77 to contact 84 at a temperature which reflects approximately 30 to 35 moisture retention by the fabrics within the dryer. It will of course be understood that, should it be desired to have a dryer perform my improved drying process for optimum results with a particular fabric the temperature responsive switch 76 might well be set for another moisture retention percentage either above or below the optimum 30 to 35% range and my invention includes changeover from plaster speed to tumble speed at such percentages. The 30 -to 35% range is set forth merely as an optimum range to obtain uniformly good results for drying a board spectrum of fabrics.

Thus the mechanism shown in FIGURES l and 2 will perform my new and improved drying process, the steps of one form of which are set forth in FIGURE 3. When the fabrics have been placed in the drum, the door closed and the machine started, the drum will accelerate to plaster speed. The drum will then rotate at plaster speed while heat is supplied to reduce the moisture content of the fabrics below the critical moisture content. Thereafter the speed of the drum is reduced and it is rotated at tumble speed.

The dryer of FIGURES 1 and 2. may be utilized to perform the more common drying process wherein the fabrics within the dryer are tumbled continuously during the drying cycle. If such a drying cycle is desired member 6 is rotated so that switch 87 is moved from engagement with contact 86 into engagement with contact 90. With such a circuit arrangement coil 55 will be immediately energized and governor clutch 48 will be activated to cause the dryer to rotate at the lower speed during the entire drying process.

It will be understood that a number of other mechanisms and control circuits are known by which many different terminal portions for the drying cycle could be provided. For instance, by using a common two-speed clutch in place of the governor clutch 48 the machine 1 may be caused to cycle between plaster speed and tumble speed as switch 76 cycles between contact 84- and contact 77. This would result in a drying cycle in which the drum rotates at plaster speed when the heater is activated and at tumble speed when the heater is deactivated. FIG- URE 4 schematically illustrates such a machine. It shows a dryer drum connected to a drive motor through a conventional two speed clutch, with an associated speed control.

From the standpoint of shrinking and felting the best results with this alternative mode of operation will be obtained when the first period of operation at plaster speed continues until the moisture content of the fabrics has been reduced to about the level of the critical moisture content.

With large loads, where the fabric annulus is thick, the exhaust temperature may indicate the moisture is approaching the critical level when, in fact, only the radially inner portion of the fabric annulus is at this level. The alternative plaster speed and tumble speed mode of operation can be used to give a faster, more uniform drying with acceptable shrinking and felting. In such an embodiment the drum would accelerate to plaster speed and rotate at that speed for a predetermined period of time, for instance until the outlet temperature rose to a predetermined level. The drum would then be decelerated for a brief period of tumble operation to redistribute the fabrics. Then the drum again would be accelerated and operated in the plaster speed range. This process would be repeated a number of times to insure uniform drying.

Drying cycles having other terminal portions come within the spirit and scope of my invention.

While in accordance with the patent statutes I have described what at present is considered to be the preferred embodiment of my invention and it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the invention.

What I claim as new and desire to secure bv Letters Patent of the United States is:

1. The process of drying fabrics of rotatable receptacle wherein said receptacle is rotated at plaster speed in the range (in revolutions per minute) between about 2933.9 Drum radius in feet as a minimum and about 2933.9 \I V Drum radius in feet as a maximum while heat is supplied to said receptacle to evaporate the moisture from the fabrics until the percentage of moisture remaining in the fabrics is approximately the critical moisture content of the fabrics.

2. The process of drying fabrics in a rotatable receptacle comprising the steps of accelerating said receptacle to a plaster speed in the range (in revolutions per minute) between about Drum radius in feet as a minimum and about y. Drum radius in feet Drum radius in feet as a minimum and about Drum radius in feet as a maximum, rotating said receptacie at said plaster speed while supplying heat to said receptacle to evaporate moisture from the fabrics until the percentage of moisture remaining in the fabrics is approximately the critical moisture content of the fabrics, then reducing the speed of said receptacle and rotating said receptacle at a speed below said plaster speed range to cause the fabrics to tumble Within said receptacle for the remainder of the drying process.

4. The process of drying fabrics in a receptacle rotatable about a non-vertical axis comprising the steps of accelerating said receptacle to a plaster speed in the range (in revolutions per minute) between about Drum radius in feet as a minimum and about Drum radius in feet as a maximum, rotating said receptacle at said plaster speed while supplying heat to said receptacle to evaporate moisture from the fabrics until the fabrics retain about 30-35% moisture, then reducing the speed of said receptacle and rotating said receptacle at a speed below said plaster speed range to cause the fabrics to tumble within said receptacle for the remainder of the drying process.

5. The process of drying fabrics in a receptacle rotatable about a non-vertical axis comprising the steps of accelerating said receptacle to a plaster speed in the range (in revolutions per minute) between about 2933.9 Drum radius in feet as a minimum and about 2933.9 W }6 Drum radius in feet References Cited UNITED STATES PATENTS 8/ 1943 Breckenridge 34-45 X 11/1960 Worst 68-19 X CHARLES I. MYHRE, Primary Examiner. FREDERICK C. MATTESON, ]R., Examiner. J. J. CAMBY, Assistant Examiner.

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