US3508340A - Laundry apparatus with dryer heat control - Google Patents

Description

April 28, 1970 R. J. KOMBOL 3,508,340

LAUNDRY APPARATUS WITH DRYER HEAT CONTROL Filed April l2, 1958 3 Sheets-Sheet 1 f Mx; im 0 R0 7 /V 0l 7 '-7 msn TEM. memes I Dv\ aff Y MMSE /HDT VARIA REG Am nFF snAK/ it b sum WARM caw usm I [my my: STAR FULL 10 START s To fw a Ua J fr/6.5

| i INVENTOR. RA l PH //O/f//OL Aprll 28, v197() R. J. KOMBOL 3,508,340

, LAUNDRY APPARATUS WITH DRYER HEAT CONTROL I Filed April 12, 1968 5 Sheets-Sheet `2 BY F76. 4. U

April 28, 1970 R. J. KoMBoL. 3,508,349

LAUNDRY APPARATUS WITH DRYER HEAT CONTROL lFiled April 12, 1968 A 5 sheets-sheet a United States Patent O 3,508,340 LAUNDRY APPARATUS WITH DRYER HEAT CONTROL Ralph J., Kombol, Connersville, Ind., assignor to Philco- Ford Corporation, Philadelphia, Pa., a corporation of Delaware Filed Apr. 12, 1968, Ser. No. 720,787 Int. Cl. F26b 1'9/00 U.S. Cl. 34-48 7 Claims ABSTRACT OF THE DISCLOSURE An automatic clothes dryer providing a drying cycle for permanent press clothing. The dryer includes control circuitry providing an initial high heat input rate for a period of time terminated in response to attainment by a clothes temperature sensor of a temperature indicative of a dry-clothes condition. If the sensed temperature indicates that drying is not complete, the sensor is operable again to energize the heater, but at a lower heat input rate to preclude adverse eilects of high temperatures on the clothing as it approaches a dry condition. Either program of heating is followed by a cool-down period, during which there is no input of heat.

BACKGROUND OF THE INVENTION This invention relates to laundry apparatus, and more particularly to improved apparatus for drying fabrics.

One known type of such apparatus includes a perforate clothes container mounted within an enclosure, and means for heating air and for circulating it through the container to dry the clothes. In order to maintain the temperature of air in the container within predetermined limits safe for the clothes being dried, suitable thermostatic control means are provided in combination with the means for heating. In general, for the initial stages of drying when the moisture content of the clothes is relatively high, substantially elevated drying temperatures can be maintained safely due to the temperature stabilization effect derived from absorption of heat by excess moisture in the clothes at latent heat of vaporization. For the linal stages of drying, when much of the moisture has been driven out, the rate of heat input is reduced to prevent the clothes from exceeding a safe temperature, preferably about 170 F. Advantageously, temperatures of permanent press fabrics can be closely controlled by this principle to prevent temperature extremes that might discolor or set stains in the fabrics. The initial high moisture content in such fabrics permits them to withstand the above described rapid heating at the beginning of a drying cycle.

The present invention recognizes that frequently, due to the relatively light thermal loading afforded by most articles of clothing and the like made from permanent press fabrics, such initial rapid heating as described above may be sufficient completely to dry the articles, without need for resorting to further heating at a lower input rate.

It is therefore a general objective of this invention to provide control circuit means for testing the dryness of such articles after an initial period of high heat input to determine whether additional heating at a lower temperature is necessary.

SUMMARY OF THE INVENTION In achievement of the foregoing, as well as other general objectives, the invention contemplates provision, in an automatic clothes dryer, of means for achieving a drying cycle for clothing of the permanent press type. Such means includes control circuitry aifording an initial high rate of heat input for a period of time followed by a period of heating at a lower heat input rate. Either period of heat- "ice ing is terminated in response to operation of a clothes temperature sensor. The invention recognizes that heating at the higher rate may be sufficient to complete the drying cycle for a particularly light clothes load. However, if drying is not complete, the clothes temperature sensor is operable again to energize the heater at its lower rate of heat input, to preclude adverse effects of high temperatures as the clothes approach a dry condition. The control circuitry provides a time-controlled cool-down period after drying is completed either as a result of heating at the high input rate, or as a result of heating at the combined higher and lower rates.

Preferred means for achieving the objectives and advantages of the invention are set out in the following description, taken in light of the accompanying drawing.

BRIEF DEECRIPTION OF THE DRAWING FIGURE l is a perspective showing of laundry apparatus embodyingthe invention;

FIGURE 2 is an elevational showing on a larger scale, and with parts broken away, of the apparatus illustrated in FIGURE 1;

FIGURE 3 is a larger scale showing of control panel structure seen on the apparatus illustrated in FIGURE l;

FIGURE 4 is a wiring diagram illustrating electrical control circuitry associated with the control panel illustrated in FIGURE 3, and eilective to achieve the drying operation contemplated by the invention;

FIGURE 5 shows the sequence chart for the timer used in practice of this invention, and illustrated in FIGURES 3 and 4;

FIGURE 6 is a selector-switch chart showing the mechanical connections made through operation of the push buttons shown in FIGURES 3 and 4; and

FIGURE 7 is a graphic representation of some performance characteristics of apparatus embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With more detailed reference to the drawing, and first to FIGURES 1, 2 and 3, the invention is embodied in laundry apparatus that' includes both a washing machine and a dryer in a single unit. It will be understood of course that the invention also is adapted for use in separately contained dryer units. The apparatus comprises cabinet structure 10 having mounted thereon a control panel 11 and a door 12 (FIGURE l) that provides access to an opening 13 (FIGURE 2) communicating with the interior of a clothes drying chamber mounted within the cabinet structure. The clothes drying chamber comprises a horizontally extending perforate drum or cylindrical basket 14 which is mounted for rotating movement about a horizontally extending stub shaft 15 mounted in a bearing plate portion 22 of a tub 23 within which basket 14 is housed. A bearing plate construction particularly adapted for use in apparatus embodying the present invention is disclosed in U.S. Patent No. 3,038,324 assigned to the assignee of the present invention. Drive means for rotating drum 13 l includes a motor 16 provided with a pulley (not shown) arranged to drive a belt 17, the latter engaging a pulley 21 mounted on shaft 15.

For washing and rinsing operations, water at the desired temperatures is introduced into tub 23 through a hose 18 fed by conventional, solenoid controlled valve means 18a. Spent wash water is withdrawn from the tub by means of an impeller-type drain pump 19 connected to theA shaft of motor 16. This pump communicates with a sump 20, provided in a lower part of tub 23, by means of a flexible hose 19a. Drainage of the water from the tub and basket is controlled by means of a solenoid actuated valve 19b associated with the drain pump.

As is well known in the art, in either the Washing or the drying operation, basket 14 is rotated in order to tumble the clothes, and particularly during the drying operation uniformly to expose the fabrics or clothes being dried to circulating heated air, thereby facilitating the drving operation. While the ends of basket 14 are preferably imperforte, with the exception of the loading opening 13, the cylindrical surface of the basket has perforations that permit passage of heated circulating air through the basket to dry clothes disposed therein.

Tub 23 is spaced from and encloses the basket 14, and an electrical resistance heater 24 is disposed within an air duct 25 communicating with the tub in the region of its access opening. Means for cooling the circulated heated air includes a water vapor condenser 26 disposed within a wall of the tub and defined by a water distributing manifold that causes water to flow down inner surface portions of the tub. Preferably condensing water flows throughout the drying cycle, under the control of a solenoid valve 28. Circulation of the air for drying is effected by a blower 27 that withdraws air from basket 14, through perforations thereof into tub 23, over the condensing water, and outwardly of the tub through rear bearing plate 22 and duct 29. The blower redirects the dehumidified and cooled drying air through duct 38 that communicates with heater duct 25, for fiow back over heater 24 and into the tub and basket by way of their aligned access openings. Blower 27 preferably is of the rotary impeller type, and is driven by motor 16 through a pulley and belt arrangement 30. The blower is driven only during the drying cycle, such selective drive `being afforded by a clutch arrangement (not shown) associated with motor 16, and under the Control of a blower solenoid 27a (FIGURE 4). Under such arrangement energization of solenoid 27a causes the blower to be driven, and deenergization of solenoid 27a causes the blower to be stopped.

Means for sensing temperatures representative of heat conditions within the clothes drying chamber of basket 14 includes thermostats 31, 32, 33 and 34 positioned as shown in FIGURE 2, and each in heat exchange relation with various zones of the circulating air. More specifically, thermostats 31 and 34 are associated with duct 25, in the region of heater 24 for subjection to the basket inlet air, and thermostats 32 and 33 are associated with the rear bearing plate for subjection to the basket exhaust air. Preferably, each thermostat is of the type having a bimetal disc which serves as a combined sensing element and circuit modifier in a manner to be hereinafter described.

With reference also to FIGURES 4, and 6, the various phases of the washing and drying cycles of the total laundering operation are sequentially controlled by a master timer control 35. The control circuitry associated with timer 35 is illustrated in detail in FIGURE 4, and is conditioned for multi-cycle operation by means of pushbutton control switch means 36 forming part of the control panel 11 on the front of the machine. The connections made by operation of the various push buttons are graphically shown in FIGURE 6. Since the present invention is not concerned with the wash cycle, which is conventional, only those details of this cycle which are necessary to understanding of the invention are described. It will be understood that both mechanical and circuit means for achieving any one of the Washing or drying operations, including the permanent press cycle to which the invention is particularly directed, can be traced using the timer sequence chart (FIGURE 5) in conjunction with the Wiring diagram (FIGURE 4). The timer actuated switch contacts and the function or component that each such contact controls (e.g., Heat cycle 9B or Drivemotor-dry 4T) are listed across the top of the timer chart of which FIGURE 5 is comprised. The phases of the complete cycles are listed down the left hand side of the timerchart, and the timer increments are listed or numbered down the right and left hand sides of the chart. The solid vertical bars in the timer chart denote closed positions of the various timer switch contacts for each of the several cycles.

In order to trace the circuitry of FIGURE 4 using the timer sequence chart of FIGURE 5, one first locates the particular phase or step of the cycle on the sequence chart. From the chart it is determined which timer switch contacts are closed during the particular step or phase of the cycle, by noting positions of the solid vertical bars for that step. To aid in tracing the closed contacts, it is convenient to fill in the gaps of the respective closed contacts of FIGURE 4 with a dark pencil or the like. Similarly, it can be determined from FIGURE `6` which push-button switch contacts are closed. The circuitry for such particular step or phase of a cycle may then be readily traced on the wiring diagram.

Important to the invention is the fact that fabrics having substantial quantities of retained moisture at the start of the drying cycle can withstand substantial quantities of heat, since most of the initial drying energy is converted into latent heat of vaporization of the retained moisture. It is therefore possible, and desirable, to introduce a large quantity of heat during the initial stages of drying to remove this moisture as quickly as possible, to reduce the overall drying time. However, once this moisture is removed in substantial part, it becomes necessary to reduce the heat input to prevent the clothing from exceeding F.

The above described principles are particularly useful in achievement of a drying cycle for so-called permanentpress clothing. According to the present invention, the permanent-press drying cycle is accomplished by a twostage or two phase, heat input system. As is illustrated diagrammatically in FIGURE 7, the first phase of heating is at high heat input (e.g., 4400 watts) and the second phase of heating is carried out at low heat input (e.g., 1100 watts). Either phase of heating is followed by a cool-down period. Inasmuch as the illustrated dryer unit has a characteristically slow, condenser type drying system, the high heat input is used at the beginning of the drying cycle to cause rapid heating of the mass of the machine and the contained clothes to speed the drying cycle. The drying chamber inlet temperature during this first stage of heat input may reach temperatures as high as about 250 F. However, since the clothes are wet, the latent heat of vaporization of the large quantities of moisture in the clothes can maintain their temperature below about 170 F., the danger point for certain permanently pressed articles.

When the mass of the machine and clothes are heated sufiiciently, but While the clothes are still damp, the high heat input is turned off. A cool-down period of about 7 minutes duration follows. The low heat input is then initiated, and continues until such time as the exhaust temperature indicates that the clothes are dry. The low input heat is then discontinued followed by a cool-down period of about 12 minutes. During the last 7 minutes of the cool-down period an end-of-cycle signal 37 sounds, and the permanent press cycle is complete.

The permanent press cycle will now be described in more detail in terms of the operating circuitry for providing such cycle, and as illustrated further in FIG- URES 4, 5, 6- and 7.

Assuming that the permanent press drying cycle is desired, push button 36a (FIGURE 3) is depressed, thereby closing switch contacts D, F, H and K as indicated in FIGURE 6. Circuitry associated with these contacts is illustrated in FIGURE 4. With push button 36a thus depressed, timer knob 35a is advanced automatically or manually to the Dryer Start position illustrated in FIGURE 3 (corresponding to the 37th increment in FIGURE 5 closing timer actuatedswitch contacts A, 6T, 5T, 4T and 1T. Closing of these contacts completes a circuit from a 120 v. power source to the condenser water supply solenoid 28, blower solenoid 27a, heater relay 24a, drain solenoid 19b, drive motor 16, and timer motor 35. Energization of heater relay 24a connects the heater 24 to a 240 v. power source.

The timer motor circuit is completed through a circuit includingthe illustrated normally closed 1-3 position of--the cut-off thermostat 31 and timer switch -contact 1T. The timer then advances to its 38th increment, closing timer switch contact 9B, vcompleting an alternate circuit for heater relay 24a. through the heater cycling thermostat 32. Heater 24 receives its energy from the 2 40 v. power source. In the event that normally closed cycling thermostat 32 should cycle or open before completion" of the high heat input period, direct heat will continue through timer switch contact 6T. The purpose of direct heat through switch contact 6T is to insure that normally closed cut-off thermostat 31 will open before the heat is turned off. At the 39th increment timer switch contact 1T opens and contact 1B closes breaking the circuit to timer motor 35. However, cut-olf thermostat 31 is still in its normally closed 1-3 position, whereby the timer is suspended in its 39th increment. The length of time that the timer remains suspended from operation varies with the clothes-load size, i.e., large, medium, or small. Timer 35 will remain suspended until normally closed contacts 1-3 of cut-olf thermostat 31 open at about 170 F., thereby closing its contacts 1-2 to complete a circuit to the timer motor. Timer 35 then advances to the 40th increment, thereby opening switch contact 6T and breaking one of the two possible current paths to heater relay 24a; the path through switch contact 9B and the normally closed cycling thermostat 32 remain closed. Timer switch contacts 1T and 6B close at this time and 1B opens. A bypass circuit is created through timer switch contact S and closed push-button switch contact F, thereby enabling drive motor 16 to continue to run through the regular cycle olf perioid when the permanent-press drying cycle is selected. It is to be noted that both the regular and the permanent-press dry cycles share the same timer increments up to this point. Since the pushbutton switch contacts K are closed, timer 35 4will continue to advance. The timer motor energizing circuit is completed through push-button switch contacts K, timer switch contacts 6B, 4T, push-button switch contacts D, timer switch contacts 4B and 5B, to the other side of the 120 v. source. Timer 35 then advances to the 41st increment and opens switch contact 9B. Timer 35 continues through to the 47th increment to open switch contacts 6B and 1T and to close 7T and 2B. The closing of 2B applies 120 volts across air heater 24 to lower its outputs to 1100 watts.

However, and in special accordance with the invention, it is at this stage of the permanent-press drying cycle that the normally open permanent-press thermostat 33 senses the dryness of the clothes indirectly to determine whether or not it is necessary to proceed with the second stage of drying at the low heat input rate of 1100 watts. Should the clothes be dry after the rst stage of drying at the high heat input rate of 4400 watts, the temperature in the vicinity of the permanentpress thermostat 33 will not have been lowered suficiently to cause its switch contacts to open. Since thermostat 33 and the contact 7T are closed, timer 35 has a circuit to drive it directly into cool down.

If, on the other hand, switch contacts of permanentpress thermostat 33 are open, indicating the need for further drying, timer 35 will remain supended in its 47th increment until permanent-press thermostat 33 reaches about 140 F. and closes, completing the timer motor circuit through switch contact 7T and advancing the timer to the 48th increment. Timer switch contact 2B opens at this time, and the 1100 watt heater circuit is broken. This is accompanied by the closing of CII switch contact 16B, completing the timer motor circuit which then remains closed for the rest of the cool-down period. In the 53rd increment of timer operation, switch contact 3T closes completing the circuit to the end-ofcycle signal, characterized by the sounding of a bell every 6 to 7 seconds for the last 7 minutes of the cooldown period. The permanent-press cycle is then completed.

It will be appreciated that the invention provides improved apparatus for drying clothes and other articles of the permanent press type. Moreover there is provided an improved clothes dryer of the non-vented, condenser type in which the time required for drying permanentpress clothing is materially reduced through a novel twostage heating arrangement.

I claim:

1. In laundry apparatus: means'dening an enclosure for fabrics to be dried; means for moving air through said enclosure to dry such fabrics; means for heating said air sequentially at a higher heat input rate' and at a lower heat input rate; means for sensing the degree of dryness of said fabrics at the termination of said higher heat input rate; and means operable in response to the sensed degree of dryness either to initiate heating at said lower heat input rate, if the fabrics are not substantially dry, or to terminate heating, if the fabrics are substantially dry.

2. In laundry apparatus: means deiining an enclosure for fabrics to be dried; means for moving air through said enclosure to dry such fabrics; means for heating said air sequentially at a higher heat input rate and at a lower heat input rate, including a heater of the electrical resistance type selectively energizable at either a higher or a lower energy output rate; a higher voltage source and a lower voltage source; and control means operable to establish a period of operation of said heater by said higher voltage source in achievement of the recited higher heat input rate, and to sense the degree of dryness of said fabrics upon termination of said higher heat input rate, said control means being further operable in accordance with the sensed degree of dryness either to establish a period of operation of said heater by said lower voltage source in achievement of the recited lower heat Output rate, or to terminate heating.

3. In laundry apparatus: means defining an enclosure for fabrics to be dried; means for moving air through said enclosure to dry such fabrics; means for heating said air sequentially at a higher heat input rate and at a lower heat input rate, including a heater of the electrical resistance type selectively energizable at either a higher or a lower energy output rate; a higher voltage source and a lower voltage source; and control means operable to establish a period of operation of said heater by said higher voltage source in achievement of the recited higher heat input rate, and to sense the degree of dryness of said fabrics upon termination of said higher heat input rate, said control means being further operable in accordance with the sensed degree of dryness either to establish a period of operation of said heater by said lower voltage source in achievement of the recited lower heat output rate, or to terminate heating, said control means also ibeing operable to provide a cool-down period following heating of said fabrics to dry the same.

4. In laundry apparatus: means defining an enclosure for fabrics to be dried; means for moving air through said enclosure to dry such fabrics, including an air impeller and conduit means arranged to provide a closed, recirculating air ilow path; water vapor condensing means in said air ow path; means for heating said air sequentially at a higher heat input rate and at a lower heat input rate; and control means for sensing the degree of dryness of said fabrics at the termination of said higher heat input rate, said control means being operable in accordance with the sensed degree of dryness either to initiate heating at said lower heat input rate or to terminate heating.

5. Apparatus according to claim 4, and further characterized in that said means for heating air is operable 7 continuously in provision of its higher and lower heat input rates.

l6. Apparatus according to claim 5 and further characterized in that said control means is operable to provide a cool-down period following either period of heating.

7. In laundry apparatus of the type having means for tumbling clothes in an enclosure and moving heated air through said enclosure to dry fabrics contained therein, control means adapting such apparatus for use in drying so-called permanently pressed clothing, said control means comprising: means for tumbling the clothes and for establishing a low of air over such permanently pressed clothes while the latter are in a relatively wet state and with the air heated to a temperature substantially above the temperature acceptable for contact with such clothes when they are in a drier state; means for terminating heating 0f the air while continuing tumbling of the clothes to establish a cool-down period during which the clothes continue drying; means for sensing the degree of dryness References Cited UNITED STATES PATENTS 3,122,358 2/1964 Cobb et al 34-48 X 3,401,464 9/1968 Fogt et al 34-48 X 3,409,994 11/1968 Meuk 34-48 X JOHN J. CAMBY, Primary Examiner U.S. Cl. X.R.

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