US 3270436 A
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Description (OCR text may contain errors)
p 1966 D. F. FAIRGRIEVE 3,270,435
CLOTHES DRIER Filed Aug. 26, 1965 5 Sheets-Sheet 1 INVENTOR.
DONALD E FA/RGR/EVE FIG. 7 p w N Attorney p 1966 D. F. FAIRGRIEVE 3,270,435
CLOTHES DRIER Filed Aug. 26, 1965 5 Sheets-Sheet 2 INVENTOR. DONALD E FAIRGR/EVE Attornev Sept. 6, 1966 D. F. FAIRGRIEVE CLOTHES DRIER 3 Sheets-Sheet 3 Filed Aug. 26, 1963 FIG. 4
INVENTOR. DONALD F FA/RGR/EVE Attorney United States Patent 3,270,436 CLOTHES DRIER Donald F. Fairgrieve, Toronto, Ontario, Canada, assignor to Fairgrieve & Son, Limited Filed Aug. 26, 1963, Ser. No. 304,591 2 Claims. (Cl. 34-131) This invention relates to improvements in a clothes drier of the type in which drying is accomplished by tumbling clothes in a horizontally rotating drum in the presence of a controlled flow of heated air.
More particularly, the invention is directed to a drier having a drum provided with spaced peripheral baffles secured to the inner surface, the wall of the drum being perforated adjacent to its forward end. The ends of the drum are provided with central openings, the forward opening giving access to the drum for insertion and removal of the clothes and the rear opening communicating with a heating unit; means are provided to trap the lint which is removed from the clothes during the drying operation.
To be eflicient in operation a drier of this type requires uniform distribution of the air in the drum but a high throughput or flow rate of air is also desirable because with the same distribution the speed of drying will increase with the throughput, the other factor determining the drying speed, namely air temperature, being limited by the need to avoid damage to the clothes.
A high flow rate is also advantageous because it provides a sweeping action which prevents the accumulation around the insulators attached to the heating elements of particles of lint drawn in from the atmosphere; such accumulation frequently arises with slow rates of air flow and may develop to the extent of creating a fire hazard.
However, while high flow rates are desirable, the problem of ensuring uniform distribution of the air is increased because of the tendency of the air to channel in the drum. Again the advantages of increased air flow are only attained if the air temperature is maintained at the highest permissible level but for this condition to be achieved the faster flowing air must pass over the heating elements for a longer time; the obvious way of ensuring this condition is to increase the length of the elements but this affects the size of the heating unit and thus the compactness of the drier.
The invention is directed to a clothes drier having an open-ended rotatable drum operating with a high throughput of air with an arrangement for heating the air which is in a compact form.
Another object of the invention is to provide an arrangement for ensuring that the high velocity air flow is distributed uniformly in the drum to provide thorough drying of the clothes.
The operative advantages of the invention will be more fully understood from the following specification taken in conjunction with the drawings, in which:
FIGURE 1 is a cross-sectional view of a clothes drier embodying one form of the invention;
FIGURE 2 is a view in perspective of the arrangement of the drum, the heating enclosure and the exhaust duct at the base of which a fan is located;
FIGURE 3 is a View in perspective of the heating enclosure showing the disposition of the element and the convolute channel;
FIGURE 4 is a section of the drier taken along the lines 44 in FIGURE 1.
Referring more particularly to the drawings, the reference is employed to generally designate a cabinet embodying the invention. This cabinet 10 is a conventional structure of sheet metal and comprises a front wall 11, a rear wall 12 and a pair of side walls 13. A
3,270,436 Patented Sept. 6, 1966 top wall 14 closes the upper end of the cabinet 10 and a plate 15 is superimposed on the top wall 14 but separated therefrom by rubber spacers 16 to provide an air ,space for the purpose of keeping the plate 15 cool when the drier is in use.
The front wall 11 is cut away to provide a centrally disposed circular opening giving access to the interior of the cabinet 10. The upper part of the front wall 11 is covered by a plate 17 having inwardly directed flanges 18; the plate 17 is secured to the front wall 11 by means of a downwardly directed flange 19, and also to the cover plate 15 by means of pins 20 secured to the upper flange 18. The plate 17 extends the whole width of the front wall 11 and its lower inwardly directed flange 18 is positioned somewhat above the uppermost level of the opening in the front wall 11.
Another plate 21, having inwardly directed flanges 22 is secured to the lower part of the front wall 11 by means of vertical flanges 23. The plate 21 extends the whole width of the front Wall 11, its uppermost flange 22 terminating in a plane somewhat below the lowermost point of the opening in the front wall 11; the lowermost flange 22 is positioned somewhat above the floor level of the cabinet 10 to provide the usual toe space in conjunction with the front Wall 11.
A rectangular door 24 is carried by suitable hinges 25 and it consists of a vertical panel defined by marginal inturned flanges 26 which project into the rectangular recessed area framed by the upper plate 17 and the lower plate 21.
Secured to the front wall 11 of its inner side is a ring-shaped member 27 having a centrally disposed opening similar in dimension to that provided in the front wall 11. The ring-shaped member 27 and the front wall 11 are separated in conventional manner at their edges to provide a cavity, not shown, to hold an edge of a circular gasket 28, the body of which provides a seal over the inner face of the door 24. A circular U-shaped bracket 29 is secured to the inner ring-member 27 adjacent to the opening; the bracket 29 is provided with spaced apertures, each holding a bearing pin 30 composed of polytetrafluroethylene. The ring-shaped member 27 terminates in an inwardly directed marginal flange or rib 31 to which is attached a circular felt gasket 32. A drier drum generally denoted by the numeral 33 has a front face 34 which bears against the spaced bearing pins 30. The front face 34 of the drum 33 terminates in an outwardly directed flange 35 which frames an opening coaxial with the opening in the front wall 11; the outer face of the flange 35 bears against a large diameter circular plate bearing 36 also of polytetrafluroethylene which is supported by the face of the bracket 29 adjacent to the opening.
The front face 34 extends outwards of the longitudinal axis of the drum 33 in a rearwardly directed shoulder 37 to connect with another drum face 38 which has a series of perforations; the drum 33 then turns inwardly from the face 38 to a short peripheral wall 39 followed by a stepped inwardly directed horizontally disposed flange 40, the outer face of which bears against the felt 32. The shoulder 37, the perforated face 38 and the short peripheral wall 39 provide a circular cavity 41 in conjunction with the inner ring member 27 and its marginal ring 31; it will be appreciated that the circular cavity 41 provides an exit for the circulating air. The flange 40 then extends to a short flange 42 after which it turns outwardly to another short horizontal flange 43, thus providing a channel for locating the felt 32.
The flange 43 is secured to the main peripheral wall 44 of the drum 33; suitable tumbling vanes 45 secured to the peripheral wall 44 are mounted in the drum 33. The main peripheral wall 44 ends in a back wall 46- which slopes rearwardly towards the axis of the drum 33 to terminate in a marginal ring or flange 47 which defines a centrally disposed opening 48.
An electrical air heating enclosure 49 is positioned between the back wall 46 of the drum 33 and the rear wall 12 of the cabinet the cylindrical enclosure 49 is supported by members 50 secured to the side walls 13 of the cabinet 10. One end wall 51 of the cylindrical enclosure 49 has an opening 52 axially disposed with respect to the opening 48 framed by the flange 47. The cylindrical enclosure 49 is also provided with another opening 53 positioned in its peripheral wall 54-; the opening 53 permits access of the air into the enclosure 49 after which it will exit through the opening 52 and then into the drum 33 through the opening 48.
As shown more particularly in FIGURE 3, an electrical heating element 55 is contained in the cylindrical enclosure 49. and provided with suitable terminals 56 in the peripheral wall 54; the heating element 55 extends transversely in arcuate configuration around the inside of the peripheral wall 54 from one edge of the opening 53 to the other. With the object of making the drier as compact as possible, it is desirable to minimise the length of the enclosure 49 and to achieve this purpose, thus providing the longest possible travel for incoming air having a high flow rate, one end of a baflie plate 57 is secured to the inside of the peripheral wall 54 to bridge the end wall 51 and the opposed end wall 58 of the enclosure 49; the baflle plate 57 exetnds inwards past the opening 53 and also the electrical element 55 to adopt a convolute form terminating at the edge of the opening 52.
The cylindrical enclosure 49 offers a means for supporting the rear end of the rotatable drum 33; for this purpose a circular U-shaped bracket 59 is secured to the end wall 51 to frame the opening 52. In the manner explained previously with reference to the U-shaped bracket 29, spaced apertures are provided in the U-shaped bracket 59 each holding a bearing pin 60 composed of polytetrafluroethylene; these pins 60 bear against the outer surface of the back wall 46 of the drum 33. Also in a manner similar to that described with respect to the circular plate bearing 30 at the front end of the drum 33, the flange 47 at the rear of the drum 33 bears against a circular plate bearing 61 supported by the inner face of the U-shaped bracket 59.
To distribute the air evenly amongst the clothes, a frusto-conical member 62 having an axially disposed opening 63 is positioned as shown in FIGURE 1 in the rear of the drum compartment 33. The opening 63 is axially disposed with respect to the opening 52 but is somewhat less in diameter whilst the wall of the conical member 62 is spaced from the flange 47 and extends into the drum 33 being preferably concave with respect to the axis of the conical member 62. The wall of the conical member 62 in the drum 33 eventually merges into a vertical plane by flaring outwards towards the main peripheral Wall 44 but terminating considerably short thereof. This form facilitates the attachment of the Wall of the conical member 62 by suitable means, e.-g. bolts to three vertical ribs 64 disposed at 120 with respect to each other and secured normally to the inside of the back wall 46 of the drum 33, the vertical ribs 64 spacing the wall of the conical member 62 away from the back wall 46. Since the upper diameter of the opening 63 in the frusto-coni-cal member 62 is somewhat smaller than the diameter of the opening 52 in the cylindrical enclosure 49, it will be appreciated that part of the heated air emanating from the latter will be divided into two portions by the wall of the frusto-conical member 62; one portion will enter the drum 33 through the opening 63 Whereas the other portion will be directed to the outer area of the drum 33 due to the flare of the wall of the conical member 62, such air passing into the drum 33 through the apertures between the ribs 64, which will also provide a swirling action on rotation. With this arrangement the requisite uniform distribution of the air will be achieved to give the proper efliciency together with the high speed of drying due to the use of high velocity air.
As shown in FIGURE 1, a fan 65 is contained in a sealed enclosure 66 which is conveniently supported by the members 50. The sealed enclosure 66 communicates with a horizontal cylindrical enclosure 67 disposed below the drier drum 33; the other end of the cylindrical enclosure 67 connects with the circular aperture. The cylindrical enclosure 67 offers an alternative position for a lint trap, not shown, in the event that the drier is positioned at table level. In order that such a trap may be easily removed, the cylindrical enclosure 67 is closed at its front end by means of a snap-on cover plate 68.
The sealed enclosure 66 containing the fan 65 exits into a duct 69 disposed at the rear of the drum 33 in the cabinet 10, the duct 69 extending vertically at one side of the enclosure 49 containing the electrical heating element 55. As shown in FIGURE 2, the duct 69 at its upper end is conveniently flared towards the rear wall 12 of the cabinet 10 to accommodate a lint trap 70. The duct 69 is closed at its top by a hinged cover plate 71 and the rear wall 12 is provided with suitable openings 72 to allow the air to escape after it has travelled through the lint trap 70.
The fan motor shaft 73 mounts a pulley 74 and a belt 75 connects this pulley 74 with another pulley 76 attached to a suitably mounted drive shaft 77; the other end of the shaft 77 has a pulley 78 carrying a belt 79 which surrounds the drum 33 to provide its means of rotation.
The operation of the drier should be clear from the above description but it may be pointed out that the clothes to be dried are inserted into the drum 33 through the circular opening cut away in the front wall 11. When the door 24 is closed against the gasket 28, the fan 65 is switched on and the drum 33 rotates; then air introduced through suitable apertures in the rear wall 12 enters the opening 53 after which it travels around the bafile plate 57 where it is heated to the required temperature. The air then exits through the openings 52 and 48 and, as explained above, it is conveniently distributed to the outer portions of the drum 33 due to the arrangement of the hollow frusto-conical member 62 and the ribs 64; the remaining portion of the air passes through the hollow frusto-conioal member 62 thus providing even distribution of the air in the drum 33. The air then exits through the perforations in the face 38 of the drum 33 into the circular cavity 41 after which it travels along the horiz ontal cylindrical enclosure 67 into the duct 69, through the lint trap 70 and then out through openings 72 in the rear wall 12.
It will be understood and appreciated that although applicant has shown and described his invention in connection with one particular type of clothes drier, variations in the general drier structure may be made and are contemplated as being within the spirit and scope of the invention insofar as such variations are encompassed by the annexed claims.
What I claim is:
1. In a clothes drier having a cabinet, a substantially cylindrical drum in said cabinet mounted for rotation about a horizontal axis and having co-axial openings in the ends thereof, the forward end of said drum being perforated to communicate with said cabinet, a door in one wall of the cabinet closing the front opening in said drum, a fixed air heating enclosure positioned at the rear of said drum and embracing a first opening therein coaxial with said rear opening in said drum, said enclosure having a second opening to permit entrance of air and communicating with said first opening, a housing enclosed exhaust fan positioned in said cabinet outside said drum, said housing having openings connecting said cabinet with an exhaust duct and means positioned in said drum adjacent its rear opening for directing a portion of the incoming air towards the peripheral walls of said drum, said means comprising an open-ended frusto-conical member axially disposed of said first opening with its wall spaced from said drum but flaring towards its peripher-y terminating short thereof and a plurality of spacing members in said drum attached thereto and secured to said wall of said frusto-conical member.
2. In a clothes drier having a cabinet, 21 substantially cylindrical drum in said cabinet mounted for rotation about a horizontal axis and having co-axial openings in the ends thereof, the forward end of said drum being perforated to communicate with said cabinet, at door in one wall of the cabinet closing the front opening in said drum, a fixed air heating enclosure positioned at the rear of said drum and embracing a first opening therein co-axial with said rear opening in said drum, said enclosure having a second opening to permit entrance of air and communicating with said first opening, a housing enclosed exhaust fan positioned in said cabinet outside said drum, said housing having openings connecting said cabinet with an exhaust duct and means positioned in said drum for directing a portion of the incoming air towards the peripheral walls of said drum, said means comprising an open ended frusto-conical member axially disposed of the rear opening of said drum, with its Walls spaced therefrom, but flaring towards its periphery terminating short thereof, the opening at the upper end of said frusto-conical member being adjacent to but less in diameter than said first opening and a plurality of spacing members in said drum attached thereto and secured to said wall of said frusto-conical member.
References Cited by the Examiner UNITED sTATEs PATENTS 2,675,460 4/1954 Winner 219-374 X 3,035,146 5/1962 Pryor 219--369 x 3,066,422 12/1962 Douglas 34-133 X 3,085,349 4/1963 Barbee 34-s2 x