GB2026147A

GB2026147A - Laundry drier

Info

Publication number: GB2026147A
Application number: GB7924316A
Authority: GB
Original assignee: Licentia Patent Verwaltungs GmbH; Licentia Oy
Current assignee: Licentia Patent Verwaltungs GmbH; Licentia Oy
Priority date: 1978-07-20
Filing date: 1979-07-12
Publication date: 1980-01-30
Also published as: NL7905127A; DE2831932A1

Abstract

A laundry treatment machine comprises a drum (7) journalled in a housing (6), and an electrical heater (12) arranged between the housing (6) and the drum (7). A condensing device (5) effective during the drying of the laundry has surfaces (13) which are blackened or provided with a dark coating. <IMAGE>

Description

SPECIFICATION Laundry treatment machine The present invention relates to a laundry treatment machine.

In a drum drier or in a drum washing machine with drying equipment with a radiant heater arranged opposite the drum, a drum blackened on its outside is provided (DE-AS 2635 584). Through this measure, a higher proportion of the supplied heat reaches the laundry and contributes to the evaporation of the liquid in the laundry in order that the drying air attains a higher relative humidity.

According to the present invention there is provided a laundry treatment machine comprising a housing, a drum journalled in the housing, an electrical heater located between the housing and the drum and a condensing device effective during the drying of the laundry and having its surface blackened or provided with a dark coating.

Through the blackened surfaces of the condensing device, the heat exchange between the moist drying air to be condensed and the cooling medium is improved appreciably, since the dark surfaces on the one hand better absorb the heat of the drying air and the dark surfaces facing the cooling medium deliver the absorbed heat more effectively to the cooling medium.The reason for this consists in that the factor

influencing the heat resistance of the condensing device depends on the convection and radiation conditions, wherein Ckonstant = 560 degree-cm2 per watt for horizontal position and 475 degree-cm2 per watt for vertical position of a heat exchange area, which consists of sheet metal and for which the heat resistance K is to be calculated; a' is a normalized Stefan-Boltzmann constant a' = 1.25 milli-watts per degree per cm2, a is the absorption co-efficient which can have the following values: well blackened sheet metal a = 0.9 roughened copper a = 0.76 polished copper a = 0.17 polished aluminium a = 0.04 An embodiment of the present invention will now be more particularly described by way of example and with reference to the drawing, the single figure of which shows a schematic illustration of a laundry treatment machine embodying the invention in the form of a condensing laundry drier with air cooling Referring now to the drawing a laundry drier comprises an outer housing 2 closable by a door 1, with an inlet opening 3 in the rear wall and an outlet opening 4 in the front wall for a cooling air current K, which flows through a condensing device 5 constructed as heat exchanger. A drum 7, loadable through the door opening of the outer housing 2, is arranged in an interior housing 6 and journalled about an axle 8.A drying air current T, guided in a closed circuit past an electrical heater 9, is circulated by means of a blower 10, enters the drum at a perforated rear wall thereof, flows through the drum and absorbs moisture. The moist drying air is guided through the heat exchanger 5, and the condensate drains into a collecting vessel 11 and can be emptied from this. For more effective drying of the laundry, a radiant heater 12 can be provided between the drum 7 and the internal housing 6. For an effective heat exchange between the drying current T and the cooling air current K in the condensing device 5, the heat exchange areas 14 thereof are blackened or provided with a dark coating at both sides. Furthermore, the drum 7 displays blackened, preferably matt black, outer surface and inner surface at least in the region of the drum shell for an effective heat transfer from the radiating heater 12 and from the drying air current entering the drum to the laundry to be dried, while the inside surface, facing the drum shell, of the interior housing 6 is polished or carries a reflector facing the radiant heater 12.

1. A laundry treatment machine comprising a housing, a drum journalled in the housing, an electrical heater located between the housing and the drum and a condensing device effective during the drying of the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Laundry treatment machine The present invention relates to a laundry treatment machine. In a drum drier or in a drum washing machine with drying equipment with a radiant heater arranged opposite the drum, a drum blackened on its outside is provided (DE-AS 2635 584). Through this measure, a higher proportion of the supplied heat reaches the laundry and contributes to the evaporation of the liquid in the laundry in order that the drying air attains a higher relative humidity. According to the present invention there is provided a laundry treatment machine comprising a housing, a drum journalled in the housing, an electrical heater located between the housing and the drum and a condensing device effective during the drying of the laundry and having its surface blackened or provided with a dark coating. Through the blackened surfaces of the condensing device, the heat exchange between the moist drying air to be condensed and the cooling medium is improved appreciably, since the dark surfaces on the one hand better absorb the heat of the drying air and the dark surfaces facing the cooling medium deliver the absorbed heat more effectively to the cooling medium.The reason for this consists in that the factor influencing the heat resistance of the condensing device depends on the convection and radiation conditions, wherein Ckonstant = 560 degree-cm2 per watt for horizontal position and 475 degree-cm2 per watt for vertical position of a heat exchange area, which consists of sheet metal and for which the heat resistance K is to be calculated; a' is a normalized Stefan-Boltzmann constant a' = 1.25 milli-watts per degree per cm2, a is the absorption co-efficient which can have the following values: well blackened sheet metal a = 0.9 roughened copper a = 0.76 polished copper a = 0.17 polished aluminium a = 0.04 An embodiment of the present invention will now be more particularly described by way of example and with reference to the drawing, the single figure of which shows a schematic illustration of a laundry treatment machine embodying the invention in the form of a condensing laundry drier with air cooling Referring now to the drawing a laundry drier comprises an outer housing 2 closable by a door 1, with an inlet opening 3 in the rear wall and an outlet opening 4 in the front wall for a cooling air current K, which flows through a condensing device 5 constructed as heat exchanger. A drum 7, loadable through the door opening of the outer housing 2, is arranged in an interior housing 6 and journalled about an axle 8.A drying air current T, guided in a closed circuit past an electrical heater 9, is circulated by means of a blower 10, enters the drum at a perforated rear wall thereof, flows through the drum and absorbs moisture. The moist drying air is guided through the heat exchanger 5, and the condensate drains into a collecting vessel 11 and can be emptied from this. For more effective drying of the laundry, a radiant heater 12 can be provided between the drum 7 and the internal housing 6. For an effective heat exchange between the drying current T and the cooling air current K in the condensing device 5, the heat exchange areas 14 thereof are blackened or provided with a dark coating at both sides.Furthermore, the drum 7 displays blackened, preferably matt black, outer surface and inner surface at least in the region of the drum shell for an effective heat transfer from the radiating heater 12 and from the drying air current entering the drum to the laundry to be dried, while the inside surface, facing the drum shell, of the interior housing 6 is polished or carries a reflector facing the radiant heater 12. CLAIMS

1. A laundry treatment machine comprising a housing, a drum journalled in the housing, an electrical heater located between the housing and the drum and a condensing device effective during the drying of the laundry and having its surface blackened or provided with a dark coating.

2. A laundry treatment machine as claimed in claim 1, wherein the condensing device comprises a liquor container having matt black surfaces and acted on by cooling water, the drum being received within the condensing device.

3. A laundry treatment machine as claimed in claim 1, wherein the condensing device comprises a plurality of closely spaced layers held together in a frame to form heat exchange areas between a cooling medium and a current of drying air, the frame being provided with respective inlets and outlets for the drying air and the cooling medium.

4. A laundry treatment machine as claimed in claim 3, wherein the heat exchange areas have matt black surfaces.

5. A laundry treatment machine as claimed in any one of the preceding claims, wherein the drum has blackened inner and outer surfaces.

6. A laundry treatment machine as claimed in any one of the preceding claims, wherein the surfaces of the condensing device are roughened.

7. A laundry treatment maching substantially as hereinbefore described with reference to the accompanying drawing.