US3553850A

US3553850A - Dryer

Info

Publication number: US3553850A
Application number: US757899A
Authority: US
Inventors: Fredrik Adolf Schuurink
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-09-08
Filing date: 1968-09-06
Publication date: 1971-01-12
Anticipated expiration: 1988-01-12
Also published as: SE368454B; FR1579344A; NL6712370A; GB1221208A; DE1785263A1

Abstract

A DRYER FOR LAUNDRIES AND THE LIKE HAVING A DRUM ROTATABLE ABOUT AN AXIS IN A STATIONARY CASING. DRYING AIR IS SUPPLIED THROUGH AN ENCLOSURE AT THE CENTRAL PORTION OF THE REAR WALL AND IS BLOWN BY A FAN. THE DRUM IS PROVIDED WITH A PLURALITY OF APERTURES IN THE FRONT WALL TO DISCHARGE THE DRYING AIR. THE CASING IS CONSTRUCTED IN SUCH A WAY THAT THE DRYING AIR IS RETURNED FROM THE FRONT TO THE REAR OF THE DRUM WHERE PART OF THE AIR IS FED TO THE ENCLOSURE CONTAINING THE FAN THROUGH A NARROW OPENING AT THE REAR END OF THE ENCLOSURE AND THE REST OF THE AIR IS EXHAUSTED INTO THE ATMOSPHERE.

Description

United States Patent US. Cl. 34-133 3 Claims ABSTRACT OF THE DISCLOSURE A dryer for laundries and the like having a drum rotatable about an axis in a stationary casing. Drying air is supplied through an enclosure at the central portion of the rear wall and is blown by a fan. The drum is provided with a plurality of apertures in the front wall to discharge the drying air. The casing is constructed in such a way that the drying air is returned from the front to the rear of the drum where part of the air is fed to the enclosure containing the fan through a narrow opening at the rear end of the enclosure and the rest of the air is exhausted into the atmosphere.

The invention relates to a dryer and more particularly to a dryer for laundry, suitable for use in the home and of the type with a drum rotatable about an axis in a stationary casing, in which the drying air is supplied through an enclosure of the fan through the central portion of the rear wall and the drum is provided with apertures to discharge the drying air.

Such a dryer is known from the Dutch Pat. 109,682. In this known dryer the drying air is discharged right away through the discharge apertures to the atmosphere and so that only dry heated fresh air is blown into the drum.

The general object of the invention is to provide a novel dryer of the type mentioned in the first paragraph having a better efiiciency than the dryer known from said Dutch patent. To this end the dryer of the invention is characterised in that the casing is constructed in such a way that the drying air is brought back from said discharge openings into the enclosure of the fan through a narrowed opening at the rear end of the enclosure debouching into a wide duct communicating with the atmosphere, and that a discharge opening to the atmosphere is provided in the path along which the air is brought back through the casing.

By means of these measures only a part of the air passing through the drum is discharged and fresh air is only supplied to replace the discharged air. The amount of discharged air might be enlarged or reduced at a constant diameter of the discharge opening by reducing or enlarging the narrowed opening, it being possible in this way to have an optimum efliciency at a determined heating capacity. From tests it appeared that with the dryer according to the invention a substantial improvement of the efficiency can be reached.

Also according to the invention the narrowed opening is an annular slit between the rear end of the enclosure of the fan and a wall of the casing, said wall leaving an opening substantially corresponding to the inlet opening for the drying air of the enclosure.

In this way a simple device is obtained with a great cross-section area for the supply of fresh air.

With a dryer having a drum with its axis horizontal and the front wall of the drum being provided with a closable opening to insert or withdraw the laundry, and with the rear wall of the drum being tapered towards the front wall, according to the invention preferably the discharge openings are only provided in the portion of the front wall beside the closable opening, the casing being provided with walls forming together with said portion of the front wall of the drum, the cylindrical part of the drum and said rear wall of the drum the path to bring back the drying air.

In this embodiment the drying air is completely passed round the laundry, said rear wall having not only the known advantage of leading the laundry along the opening through which the drying air is blown into the drum, but also the advantage of a greater space for the circulating air before entering the narrowed opening, in this way no throttling can take place in said space.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings.

A drum 1 of the dryer rotatable about its horizontal axis has in its front wall 2 a filling opening 3, the rear wall 4 being formed as a frustum of a cone.

In the space formed by the conical rear wall 4 of the drum is provided a pressure fan 5 with an enclosure 6, said fan 5 bearing in said rear wall 4 and air being blown with a certain overpressure through said enclosure into the drum 1.

The air is discharged from the drum 1 through apertures 7 in the front wall 2 aside the filling opening 3 and is then passed through the spaces between the portion of the front wall 2 of the drum 1 provided with apertures 7 and the wall 8 of the stationary casing, between the cylindrical wall 9 of the drum 1 and the wall 10 of the casing, and between the rear wall 4 of the drum and the wall 11 of the casing to an annular slit 12 between the rear end of the enclosure 6 and the inner edge 13 of the wall 11 of the casing. From there the air passes again through the enclosure 6 into the drying space.

In the wall 11 of the casing there is provided an opening 14 communicating the space between the rear wall 4 of the drum 1 and the wall 11 of the casing with the atmosphere, through which a portion of the drying air is driven to the atmosphere.

The opening formed by the inner edge 13 in the wall 11 communicates with the atmosphere. Near said opening is provided an electrical heating device 16 serving to heat the fresh air drawn in by means of the flow of the air passing through the slit 12.

The path of the air passing through the device is indicated with arrows.

It appeared from tests that with the same consumption of energy the device according to the invention evaporates about 25% more water than a device according to the Dutch Pat. 109,682. In said tests the temperature of the atmosphere was 18-20 C. at a relative humidity of the air of 50 to 60%. It appeared that the best results were obtained with an overpressure of the fan of about 8 millimeters, a relative humidity of the discharged air of about and a discharged amount of 6- 4 of the total amount of air circulating through the device.

It is noted that the invention is not restricted to the shown and described embodiment. It is e.g. also possible to provide a device with a drum having its axis vertical with a recirculation system of the drying air. It is also possible to obtain the function as an injector by passing said air through an annular space with an axis coaxial with the driving shaft.

The embodiment according to the drawings, however, is preferred because of the already known advantage of the rear wall of the dryer with its shape of a frustum of a cone and because of the advantage that the slit can be provided in a more simple way than the annular space.

What I claim is:

1. A dryer for laundries and the like comprising a stationary casing, a drum rotatably mounted within said casing and forming an annular space therebetween, means to rotate said drum, a fan enclosure substantially centrally mounted in one end of said drum, an air inlet opening in said casing adjacent said enclosure, one end of said enclosure being open to atmosphere through said opening, a fan mounted in said enclosure, apertures formed at the end of said drum remote from said enclosure, said fan drawing air in through said enclosure from the atmosphere and passing it through said drum and said apertures to return via said annular space formed between said casing and said drum, and passage means for ejecting part of said return air to atmosphere and feeding the remainder to said enclosure wherein it is mixed with ambient air and recirculated through said dryer.

2. A dryer according to claim 1 wherein said passage means comprises a radial slit formed between the open end of the fan enclosure and a Wall of said casing, said inlet opening in said casing being of substantially the same size as said open end of the enclosure and slightly spaced 4 therefrom, said slit providing a ath for the recirculating air.

3. A dryer according to claim 1 in which said drum has a horizontal axis and is provided with front and rear end walls, a filling opening in said front wall, means to close said filling opening, said apertures being provided in that portion of the front end wall adjacent the filling opening, said rear end wall having a frusto-conical shape directed towards said front end wall, said enclosure being mounted in said rear end wall.

References Cited UNITED STATES PATENTS 3,060,593 10/1962 Flora et a1. 34-133 3,333,346 8/1967 Brucken 34-l33X 3,402,477 9/1968 Hubbard 34-133X 3,419,969 1/1969 Freze 34-133X 2,996,809 8/1961 Shahter 34133 3,483,632 12/1969 Triplett 34--133X MARTIN P. SCHWADRON, Primary Examiner T. W. STREULE, Assistant Examiner