US2807890A

US2807890A - Laundry machine having improved temperature sensing means

Info

Publication number: US2807890A
Application number: US538893A
Authority: US
Inventors: Aidan M Stone
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1955-10-06
Filing date: 1955-10-06
Publication date: 1957-10-01
Anticipated expiration: 1974-10-01
Also published as: FR70861E; US2880521A; FR1165420A

Description

/ Oct. 1, 1957 LAUNDRY MACHINE HAVING IMPROVED TEMPERATURE SENSING MEANS Filed 001:. 6, 1955 3 Sheets-Sheet 1 FIG. I

5| I I 1/ a a O m 1 I I I J 23 l 7 4e 25 20 INVENTOR.

AIDAN M. STONE HIS ATTORNEY Oct. 1, 1957 A. M. STONE LAUNDRY MACHINE HAVING IMPROVED TEMPERATURE SENSING MEANS Filed Oct. a, 1955 s Sheets-Sheet 2 'INVENTOR. AIDAN M. STONE f. M}; HISATTORNEY Oct. 1, 1957 A, STONE 2,807,890

LAUNDRY MACHINE HAVING IMPROVED TEMPERATURE SENSING MEANS Filed Oct 6, 1955 5 Sheets-Sheet a INVENTOR.

AIDAN M. STONE HIS ATTOQNEY United States Patent LAUNDRY MACHINE HAVING MPROVED TEMPERATURE. SENSING MEANS Aidan M. Stone, Louisville, Ky., assignor to General Elem tric Company, a corporation of New York Application October 6, 1955, Serial No. 538,893

Claims. (Cl. 34-48) My invention relates to laundry machines having a clothes basket rotatable about a non-vertical axi and more particularly it relates to such machines including heaters and thermostatic means for controlling the heaters.

Heaters are customarily provided in domestic clothes drying machines to aid in the extraction of moisture from clothes being dried. Heaters are also provided in combination washer-dryers for heating the wash water during the washing cycle and for extracting moisture from the clothes during the drying cycle. In both types of machines the heater circuit ordinarily includes a thermostat for controlling the heaters during the drying cycle to maintain suitable temperatures within the machine. Due to its accuracy it is preferred in some instances that a thermostat of the hydraulic type be used for the heater control. However, it has been found that when this type of thermostat is used, its accuracy is seriously affected by the accumulation of lint on the temperature sensing element if the element or bulb is exposed within the tub, casing, or other chamber enclosing the rotating clothes basket. In certain machines though in which the clothes basket is closed by an imperforate tub, the sensing element must almost of necessity bepositioned within the tub. These machines do not include any air circulating means and the moisture extracted fromthe clothes by the heaters is condensed out of the air within the tub by means of a cold wall condenser or a spray condenser. Since there isno air flow into and out of the tub, the temperature inside the tub itself must therefore be sensed to obtain accurate temperature control. It is in this type of machine particularly that a problem has been created by the accumulation of lint on the temperature sensing element.

Accordingly it is a primary object of my invention to provide a new and improved arrangement for mounting a temperature sensing element within the tub of a laundry machine, whereby the element is effective to sense machine temperature accurately but yet is not subject to lint accumulation. V

A more specific object of my invention is a temperaturesensing element arranged within the tub of a laundry machine, whereby only a minimum horizontal surface is presented by the element for the deposit of lint and also whereby thenair and water circulation set up by the rotating basket of the machine tends to remove any lint which is deposited.

In carrying out my invention I provide a laundry machine having a'clothes basket rotatable about a nonvertical axis, and an imperforate tub enclosing the basket. The machine further includes a heater for heating the clothes being tumbled in the basket and a thermostat for controlling the energization of the heater. A temperature sensing element is provided for actuating the thermostat, and by my invention I position the element so that. it accurately senses the. temperature within the tub" but yet is' not subject to" lint accumulation. The temperature sensing element comprises a hydraulic tube, and

ice

it is mounted between the outer cylindrical wall of the basket and the adjacent wall of the tub. In this position it is effective to sense accurately the temperature of the basket and the clothes therein. To avoid lint accumulation the tube is arranged so it extends generally circumferentially with respect to the cylindrical wall of the basket. As a result of this circumferential arrangement only a small surface is presented for the deposit of lint, and further the fluid circulation set up within the tub by the basket tends to remove any lint which may be deposited. The sensing element or tube is thereby kept substantially lint free.

The features of my invention which I believe to be novel are set forth with particularity in the appended claims. My invention itself, howevenmay be understood by reference to the following description taken in conjunction with the accompanying drawings in which:

Fig. l is a rear elevational view of a combination clothes washing and drying machine embodying my invention in one preferred form thereof, the view being partially broken away and partially in section in order to illustrate details of my invention; 1

Fig. 2 is a side elevational view of the machine of Fig. 1 with the side panel removed; 7

Fig. 3 is a side elevational view of the machine with certain surfaces broken away and with certain surfaces in section to illustrate details; and

Fig. 4 is a fragmentary sectional view showing the manner in which the temperature sensing element is arranged within the machine.

Referring now to the drawings I have shown therein a domestic laundry machine 1 comprising a combination washer and dryer. The machine 1 is of the horizontal axis type, that is it includes a clothes basket 2 which is rotatable about a generally horizontal axis. The basket 2 includes front and

rear walls

3 and 4 and a connecting side or outer wall 5 (see Fig. 3). The outer wall 5 is cylindrical in shape and is provided with a plurality of perforation or holes as shown. The rear Wall 4 is reinforced by a suitable plate 6.

The cylindrical basket 2 is mounted within an imperforate tub structure 7 which encloses it on all sides. The tub 7 includes a front wall 8, a rear wall 9 and a connecting side or outer wall 10. In my preferred embodiment the outer wall 10 is generally cylindrical in shape and has the same center as the cylindrical Wall 5 of the basket 2. The basket is rotatably supported from the tub structure by a horizontally extending shaft 11 which is mounted in an elongated bearing 12 hung from the rear wall 9 of the tub structure (see Fig. 3). The shaft 11 as well as supporting the basket also serves as the means for turning it during the operation of the machine. The basket is mounted on the shaft'by an internally-tapered hub 13 secured centrally of the basket rear wall and the reinforcing plate 6. The tub and the basket are provided respectively with

openings

14 and 15 in the front walls thereof which are aligned with a door opening 16 in the frontwall of the appearance cabinet 17 which surrounds the tub. A hinged door 18 mounted on the appearance cabinet seals against a gasket 19 around the tub opening 14 to close off the tub during operation of the machine. n

The tub structure 7 and the appearance cabinet 17 are both mounted on a suitable base structure 20 at the base of the machine. The tub specifically is supported therefrom by means of a plurality of brackets or arms 21 which are mounted on upstanding plates 22 fixedly attached to the base. The appearance cabinet may be welded to the base or otherwise suitably attached thereto. In addition to the tub and the appearance cabinet the base 20 alsomounts the basket drive means. The drive means comprise a motor 23 and a rnulti-speed transmission assembly 24 (see Fig. 1). The motor 23 drives the transmission assembly 24 by means of a belt 25 and the transmission assembly in turn drives the basket through a belt 26. The belt 26 specifically turns a basket drive pulley 27 which is mounted on the outer end of the basket drive shaft 11. The transmission assembly 24 is shiftable between two different gear ratios so that the basket 2 may be driven at one speed for tumbling clothes and at a second or higher speed for centrifugally extracting water from the clothes. The means whereby the transmission is shifted between the lower and higher speeds preferably comprises a solenoid operated plunger (not shown).

As mentioned above the machine 1 comprises a combination washer and dryer. That is it proceeds through a cycle of operation first washing, rinsing and damp drying the clothes and then, if desired, completely drying the clothes. The clothes basket is driven at its lower speed both for washing the clothes and for tumbling them during the drying operation. It is driven at its higher speed for extracting both wash and rinse water from them by centrifugal extraction. The machine during its sequence of operations is under the control of a suitable timer operated sequence control which energizes and de-energizes the various electrical components of the machine in a predetermined sequence. Since the sequence control forms no part of the present invention it will not be described herein. However, a sequence control and circuit suitable for the use in the illustrated machine are described and claimed in the copending application of Walter B. Gray, S. N. 512,612, filed June 2, 1955, and assigned to the same assignee as the present invention.

The machine 1 is provided with suitable water supply means whereby either hot water or a mixture of hot and cold water may be admitted to the tub 7 for washing and rinsing, purposes. The water supply means includes connections 28 and 29 (Fig. 1) through which. hot and cold water are supplied respectively. A valve controlled by a solenoid 30 admits hot water to the machine and a valve controlled by an opposed solenoid 31 admits cold water to the machine. The hot and cold water valves under the control of

solenoids

30 and 31 discharge through a common outlet conduit 32. From the conduit 32 the water passes through a suitable air gap into a funnel 33. The funnel 33 discharges into a line 34 which leads to a sump 35 which is mounted at the bottom of the tub structure 7 and communicates with the interior thereof (see Fig. 2). The break or air gap provided by funnel 33 makes it impossible for water to be siphoned from the machine to contaminate the incoming water supply line. In the illustrated machine a pressure actuated hydrostatic sensing device 36 (Fig. 1) controls both the

water solenoids

30 and 31 to produce the proper water level in the machine during the washing operation. This sensing device is connected to the interior of tub 6 by a suitable tube 37. It will be understood of course that the sensing device controls the water valve solenoids only when suitable circuits are closed by the timer operated sequence control. The water level in the tub during the washing operation is such that the lower portion of the basket is covered whereby the basket dips continuously into the water as it rotates.

The illustrated machine is of the type which uses a cold wall condenser during the drying cycle for condensing the moisture extracted from the wet clothes. The wall of the tub 7 comprises this condenser and it is cooled by flowing cold water over it. The condenser water is admitted to the machine through an additional solenoid actuated valve controlled by a solenoid 38. The solenoid 38 is energized by the sequence control during the drying operation so that the valve controlled by it passes water at a slow rate sufficient to cool the tub wall and condense the moisture extracted from the clothes. As shown in Fig. l, the condenser Water valve discharges through a separate conduit 39 into a funnel 40. An air gap between conduit 39 and funnel 4t) prevents supply line contaminzn tion.

From the funnel 40 the condenser Water flows through a line 41 into a trap element 42 which connects the interior of the tub 6 to a vent hose 43 (see Fig. 2). The condenser water flows through the trap element 42 into the tub and in doing so forms a liquid seal therein whereby air cannot escape from the tub through the vent hose 43 during the drying cycle. The arrangement of the trap 42 and in fact the venting system as a Whole are not my invention but rather are described and claimed in the copending application of Walter J. Raczynski, S. N. 538,891, filed concurrently herewith and assigned to the same assignee as the present invention.

The condenser water flowing slowly into the tub through the trap is spread over the side of the tub by an inverted V-shaped bead 44 formed on the tub wall directly below the trap. The condenser water being so spread out cools a substantial portion of the area of the tub wall whereby there is provided a large cool surface for condensing the moisture extracted from the clothes. Incidentally it will be noted that during the washing portion of the machine cycle there is no condenser water flow whereby no seal is formed in the trap 42 and the machine is continuously vented through the tube 43.

The wash and rinse water used during the washing portion of the operation and the condenser water and the moisture extracted from the clothes during the drying operation are discharged from the machine through the sump 35. A discharge hose 45 leads from the sump to a pump 46 which is connected to the household drain by a flexible conduit 47 (see Fig. 1). The pump 46 is energized at suitable times to drain the dirty wash and rinse water i from the machine and is continuously energized during the drying operation.

To warm the wash water during the washing portion of the cycle and also in order to heat the clothes during the drying portion of the cycle, there is provided in the machine a heater assembly including two

heaters

48 and 49. These heaters are mounted within the upper portion of the tub 7 so that when energized they heat the basket 2. The heating units are preferably of the sheathed type in which a resistance wire is maintained in spaced relationship within an outer sheath by a highly compressed, granulated, heat conducting, electrically insulating compound such as magnesium oxide. Such heating elements are sold under the trademark of Calrod and are available commercially. When the heaters are energized during the washing cycle, they heat the water by first heating the basket. Then as the basket dips into the wash water at the bottom of the tub, it in turn heats the water. In other words, the rotating basket serves as an effective heat transfer means between the heating elements and the water or other washing liquids. When the heaters are energized during the drying cycle, the heat transferred to the basket is then passed on to the clothes to cause vapor migration out of the clothes. Since the outer cylindrical shell 5 of the basket is perforated, some of the heat from the heating elements passes directly to the clothes by radiation, and some also passes thereto by diffusion.

During the drying cycle the

heaters

48 and 49 are under the control of a hydraulic-type thermostat 50 which is mounted in the backsplasher 51 of the appearance cabinet 17. Preferably the thermostat 50 not only controls the energization of the heaters so as to prevent the machine temperature from rising above that suitable for drying clothes, but is also so connected to the sequence control that it is effective to control the duration of the drying cycle itself. A suitable circuit for accomplishing such control is shown in the aforesaid Gray application S. N. 512,612.

The thermostat 50 may be of any suitable hydraulic type but preferably is of the expansible bellows type.

As shown it includes a manually adjustable control knob 52 whereby its response, i. e. its actuating temperature, may be varied. The thermostat 50 is actuated by means of a temperature sensing element 53 which is positioned within the tub 7 adjacent the basket 2 (see Fig. 1). It is important that the sensing element be positioned within the tub and adjacent the basket in order that it will sense accurately the basket and clothes temperature. The sensing element as shown is connected to the thermostat by means of a suitable hydraulic line or capillary tube 54.

In order that the sensing element 53 will respond properly to basket temperatures, it is necessary that no appreciable amount of lint collect thereon. During the drying operation there is of course a considerable amount of lint circulating around within the machine. By my invention the sensing element 53 is so constructed and arranged that lint collection thereon is substantially avoided. As is more clearly shown in Fig. 4 the sensing element 53 comprises a U-shaped hydraulic tube. The two legs of the element are positioned very closely together and are supported from the tub by the same mounting

elements

55 and 56. These mounting

elements

55 and 56 are formed of heat insulating material, as for example rubber, so as to insulate the sensing element thermally from the tub.

So that lint will not collect on the sensing element 53 I have arranged the sensing element so that it extends generally circumferentially with respect to the cylindrical side walls 5 and of the basket and the tub. In other words the sensing element is arranged so that it extends generally around the basket and the tub rather than across them. In my preferred embodiment the sensing element is curved as shown in Fig. l with the center line of the basket comprising the approximate center of the curve.

When the thermostat sensing element 53 is arranged in this circumferential manner very little or no horizontal surface is presented for the deposit of lint. Thus lint collection is minimized since lint does not deposit readily on more or less vertical surfaces. Also, the flow of air and/or water in the tub moving with the basket tends to remove any lint deposited on the elements. During the washing cycle of the machine the rotation of the basket sets up a flow of water and air moving along with it and during the drying cycle it sets up a flow of air alone. Both these flows moving with the basket tend to remove any lint happening to fall on the element or bulb 53. The flow of air and water set up during the washing cycle is particularly effective in keeping the element 53 free of lint. However if the element is not oriented in the generally circumferential manner of my invention, this fluid circulation set up by the basket is not effective to remove the lint. Rather strings of lint become wrapped around the element and the response and accuracy of the thermostat is seriously eifected. Thus my improved arrangement of the temperature sensing element takes advantage of the fluid circulation set up in the tub by the rotating basket, whereas those thermostatic arrangements heretofore available do not. It will be noted that in my preferred embodiment the temperature sensing element 53 is disposed within a recess 57 in the cylindrical wall 10 of the tub. This recess 57 provides suflicient clearance between the rotating basket and the element 53 for safe operation. Also, the positioning of the sensing bulb within the recess 57 has the additional advantage that it prevents lint build up at the point where the hydraulic or capillary tube enters the tub. The basket 2 rotates in the direction indicated by the arrow in Fig. l and the upper wall 58 of the recess guides or deflects lint flowing with the basket outwardly from the top of the tube 53 so that it does not deposit thereon. In other words the wall 58 acts as a shield preventing lint from falling directly onto the bulb.

Although by my invention the sensing element 53 extends generally circumferentially with respect to the basket and the tub, it need not extend exactly circumferentially thereto. Rather as shown in Fig. 4 it can be slanted slightly with respect to a true circle around the center line of the basket. The advantage of slanting the sensing element slightly is that it then senses the basket temperature across a portion of the width thereof. In other words it senses the temperature of what in elfect is a'band'extending'around the basket. It is advantageous to sense the average temperature over such a width since it is possible that a hot spot may occur in either of the

heating elements

48 and 49 resulting in a narrow strip around the basket being heated to a higher temperature than any other portion of the basket. The slanting of the sensing element 53 avoids the possibility of its sensing only the temperature of such a hot strip and thus giving a false result. The slight slanting of the sensing element from the true circumferential direction does not result in any appreciable amount of lint collection. So long as the element extends generally circumferentially with respect to the basket, very little lint will be deposited, and the fluid circulation set up by the basket will be elfective to remove this lint from the element.

From the above it will be seen that by my invention I have provided a new and improved arrangement of a temperature sensing element within a laundry machine, whereby the sensing element is disposed within the tub of the machine but 'yet is not subject to lint collection. Due to my generally circumferential mounting of the temperature sensing element substantially no horizontal surface is presented for the collection of lint, and also the fluid circulation set up within the tub by the basket 'is effective to remove any lint which may be temporarily deposited thereon. The mounting of the generally circumferentially directed thermostat within a recess in the tub wall so that the top wall of the recess acts as a lint deflector has been found to be particularly advantageous.

Incidentally it will be noted that in the illustrated machine a safety thermostat 59 provides overtemperature protection during both the washing and drying cycles.

While in accordance with the patents statutes I have described what at present is considered to be the preferred embodiment of my invention it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and I, therefore, aim in the appended claims to cover all such equivalent variations that fall within the true spirit and scope of my invention.

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

1. In a laundry machine, a clothes basket rotatable about a non-vertical axis, said basket having a cylindrical outer wall, a tub enclosing said basket, means for rotating said basket, a heater for heating the clothes being tumbled in said basket, and means for controlling the energization of said heater, said means including a thermostat and a temperature sensing element for actuating said thermostat, said sensing element comprising a curved hydraulic tube positioned between said cylindrical Wall of said basket and the side wall of said tub and extending generally circumferentially with respect to said cylindrical Wall of said basket, thereby to present substantially no horizontal surface for lint collection and to provide for the removal of lint therefrom by the fluid circulation set up by said basket, and said tube extending slantwise across a portion of said basket thereby to sense the basket temperature across a relatively wide band broader than the diameter of said tube.

2. In a laundry machine, a clothes basket rotatable about a horizontal axis, said basket having a cylindrical outer wall, a tub enclosing said basket, said tub having a generally cylindrical side wall provided with a circumferentially extending recess, means for rotating said basket, a heater for heating the clothes being tumbled in said basket, and means for controlling the energization of said heater, said means including a thermostat and a temperature sensing element for actuating said thermostat, said sensing element comprising a curved hydraulic tube disposed inside of said tub within said recess, said tube extending generally circumferentially with respect to said cylindrical walls of said basket and said tub whereby lint collection on said tub is substantially avoided, and said tube extending slantwise across said recess thereby to sense the basket temperature across a relatively wide band broader then the diameter of said tube, and said recess having a top wall protruding outwardly into the air gap between said tub and said basket to deflect lint away from said tube.

3. In a laundry machine, a clothes basket rotatable about a horizontal axis, said clothes basket having a cylindrical outer wall, a tub enclosing said basket, said tub having a generally cylindrical side wall, means for rotating said basket, electrical heating means for heating the clothes being tumbled in said basket, and means for controlling the energization of said heating means, said means including a thermostat and a temperature sensing element for actuating said thermostat, said sensing element comprising a curved hydraulic tube disposed between said cylindrical Walls of said basket and said tub, said tube being U-shaped with its legs extending generally circumferentially with respect to said cylindrical walls of said tub and said basket, whereby lint collection there on is substantially avoided, and said tube extending slantwise across a portion of said basket thereby to sense the basket temperature across a relatively wide band broader than the combined width of said legs of said tube.

4. The combination of claim 3 wherein said cylindrical wall of said tub includes a circumferentially extending recess in the inner surface thereof and said U-shaped tube is disposed within said recess, with said recess having a top wall protruding outwardly into the air gap between said tub and said basket to deflect lint away from said tube.

5. In a combined clothes washing and drying machine, a clothes basket rotatable about a horizontal axis, said cloth es basket having a cylindrical outer wall, a tub enclosing said basket, means for rotating said basket, water inlet connections for introducing water into said tub, drain means for discharging said water from said tub, heating means mounted within said tub, and means for controlling the energization of said heating means, said means including a thermostat and a temperature sensing element for actuating said thermostat, said sensing element comprising a curved hydraulic tube positioned between the cylindrical wall of said basket and said tub on one side of said basket and vertically centered with respect to said basket, thereby to present a minimum horizontal surface, said tube extending generally circumferentially with respect to said cylindrical wall of said basket, whereby the flow of air and water in said tub moving with said basket tends to remove any lint deposited on said element, and said tube extending slantwise across a portion of said basket thereby to sense the basket temperature across a relatively wide band broader than the diameter of said tube.

References Cited in the file of this patent UNITED STATES PATENTS 2,336,092 Grooms Dec. 7, 1943 2,398,880 Broglie Apr. 23, 1946 2,656,695 Miller Oct. 27, 1953 2,717,457 Smith Sept. 13, 1955 2,736,970 Engel Mar. 6, 1956