EP2093322A1 - Dryer with cooled motor - Google Patents

Abstract

The dryer has a heater (10) i.e. electrical resistance heater, provided in a processing air channel (2) for heating process air, and a blower (6) provided in the air channel. A motor (7) drives a drying chamber (3), and a cooling air section (8) is provided on the channel or in a cooling air channel (22). The section is provided between an input (17) for cooling air and a heat exchanger (5). A motor cooling channel (23) is diverged out from the cooling air section, and the motor is loaded with the cooled air by the motor cooling channel. Another blower (25) is provided in the channel (23).

Description

The invention relates to a dryer with a cooled engine.

A dryer in the form of a tumble dryer is executed and used in principle as an exhaust air dryer or circulating air dryer. In any case, moist laundry items are dried by first heating dry air as so-called process air and then passing it over the wet laundry items located in a drum. The moisture contained in the items of laundry evaporates and is led out of the drum in the form of moist, warm process air. In a recirculating air dryer, the moist, warm process air is cooled by precipitation of the moisture (condensation dryer), first in a heat exchanger and then returned to the drying chamber after renewed heating. By contrast, in the case of an exhaust air dryer, the air laden with moisture after passing through the laundry drum is generally conducted out of the exhaust air dryer. Here, too, the process air can be cooled by deposition of the moisture contained in it, whereby a heat recovery can take place.

A conventional dryer has a housing and a drying chamber for objects to be dried, a process air duct in which a heater for heating the process air and a first blower, a motor for driving the drying chamber, a heat exchanger and a cold air section in the process air duct or in a Cooling air duct on. Herein, the cold air section is generally referred to the part which is located between a cold air inlet and a heat exchanger. As cold air is usually used air at a temperature which is substantially equal to the room temperature, i. the temperature of the installation room, is.

The heating of the motor used to drive the dryer determines its dimensioning and other design. In the conditions prevailing in a dryer, especially those in the housing Internal temperature of up to 60 ° C, the heat dissipation is difficult to the surrounding air around the engine. With an increase in the internal temperature, the heat dissipation from the engine deteriorates because the engine is generally air-cooled.

The object of the invention was therefore to provide a dryer that allows improved operation of the engine. Preferably, the reliability and life of the engine and thus of the dryer should be improved.

The solution of this object is achieved according to this invention by a dryer with the features of the independent claim. Preferred embodiments of the dryer according to the invention are listed in corresponding dependent claims.

The invention thus relates to a dryer with a housing and a drying chamber for objects to be dried, a process air duct in which there is a heater for heating the process air and a first fan, a motor for driving the drying chamber, a heat exchanger and a cold air section in Process air duct or in a cooling air duct, wherein an engine cooling duct branches off from the cold air section, through which the engine with cold air can be acted upon.

In a preferred embodiment of the dryer according to the invention, the cold air section is located in the process air channel. Such a dryer is designed as an exhaust air dryer, in which the process air is divided into supply air before the drying chamber and exhaust air after leaving the drying chamber.

In an alternative preferred embodiment of the dryer according to the invention, the cold air section is located in the cooling air duct. Such a dryer is designed as a circulating air dryer.

The proportion of air flowing from the cold air portion into the engine cooling passage may vary within a wide range. Preferably, a partial air flow is in Engine cooling channel up to 30%, more preferably up to 20%, of a total flow in the cold air section.

In the engine cooling passage is preferably a second fan. The engine can then be cooled particularly efficiently. Here, it is preferable that the first blower and the second blower are driven by the same engine.

Most preferably, in this embodiment of the invention, the first blower and the second blower are disposed on opposite sides of the engine. In an alternative preferred embodiment of the dryer according to the invention, the first blower and the second blower form a double-flow blower.

Most preferably, the engine in these embodiments is the engine that is also used to drive the drying chamber.

In a further preferred embodiment of the invention is located in the cooling air duct, a third fan.

The heating for heating the process air may be, for example, an electrical resistance heater and / or a second heat exchanger. Preferably, both an electrical resistance heater and a second heat exchanger are used. The second heat exchanger may be an air-to-air heat exchanger in which warm air from the drying chamber or engine compartment is used to heat the process air, or the condenser of a heat pump.

In a dryer equipped with a heat pump, the cooling of the warm, moisture-laden process air essentially takes place in the evaporator of the heat pump, where the heat transferred is used to evaporate a refrigerant used in the heat pump cycle. That's because of Heating evaporated refrigerant of the heat pump is supplied via a compressor to the condenser of the heat pump, where due to the condensation of the gaseous refrigerant heat is released, which is used to heat the supply air before entering the drying chamber (drum).

Since, as the degree of drying of the objects to be dried in the exhaust air dryer decreases, the energy required for drying decreases, the heating is appropriately regulated, that is to say in accordance with the invention. As the degree of drying progresses, its heat output is reduced.

The dryer according to the invention has the advantage that the improved cooling of the motor of the dryer can be operated at a lower temperature compared to a conventional dryer. The risk of a motor stall due to heating is reduced and thus the likelihood of the engine failing altogether. Finally, even if less material is used (reduced package length), the engine temperature can be maintained at the same level. Because of the active cooling of the motor, it can be made smaller with regard to the laminated core and winding, so that a cost advantage can be achieved without loss of function.

Further details of the invention will become apparent with reference to the FIGS. 1 and 2 from the following description of non-limiting embodiments for the dryer according to the invention and the method for its operation.

FIG. 1 shows a vertical section through a dryer which is designed as a vented dryer.

FIG. 2 shows a vertical section through a dryer, which is designed as a circulating air dryer.

In the FIGS. 1 and 2 the arrows indicate the flow direction of the process air.

The in FIG. 1 The dryer shown has, in a housing 1, a drum rotatable about a horizontal axis as a drying chamber 3, within which drivers 4 are fastened for moving laundry during a drum rotation. Supply air is guided in the process air duct 2 by means of a first blower 6 from the supply air inlet 13 via an air-air heat exchanger 5 and an electric heater 10 through the drum 3. Here, the cold air section 8 designates the part of the process air duct 2 from the inlet air inlet 13 to the air-air heat exchanger 5. From the cold air section 8, an engine cooling duct 23 branches off to the engine 7 in order to cool it by supplying cold air.

After exiting the drum 3, the process air laden with moisture is conducted in a part of the process air duct 2 designated here as an exhaust duct 9 via the air-air heat exchanger 5 to an exhaust air outlet 12. In this case, heated air from the rear of the electric heater 10, i. from the opposite side of the door 14 of the drum 3, passed through the perforated bottom in the drum 3, comes there with the laundry to be dried in contact and flows through the filling opening of the drum 3 to a lint filter 15 within a closing the filling opening door 14th Subsequently, the air flow is deflected in the door 14 down and passed in the exhaust duct 9 on to the air-to-air heat exchanger 5. As a result of cooling, the moisture absorbed by the process air from the items of laundry condenses there and is collected in a condensate tray (not shown here). The cooled and dehumidified process air leaves the exhaust air duct 9 at the exhaust air outlet 12 as exhaust air.

In the engine cooling passage 23, a second blower 25 is located in this embodiment.

The drum 3 is in the in Fig. 1 shown embodiment at the rear bottom by means of a pivot bearing and front mounted by means of a bearing plate 16, the drum 3 rests with a brim on a sliding strip 17 on the bearing plate 16 and is held at the front end. The control of the exhaust air dryer takes place via a control device 18, which can be controlled by the user via an operating unit 19.

At the in FIG. 1 In the embodiment shown, the first blower 6, the second blower 25 and the drum 3 are driven by the same motor 7, the first blower 6 and the second blower 25 being on opposite sides of the engine 7.

FIG. 2 shows a vertical section through a dryer, which is designed as a circulating air dryer. In this embodiment therefore accounts for a supply air inlet and an exhaust duct. In contrast to the embodiment of FIG. 1 the cooling of the warm, moisture-laden process air from the drying chamber 3 in the air-air heat exchanger 5 by heat exchange with cooling air in a cooling air duct 22. In this embodiment of the invention, the cold air section 8 is located in the cooling air passage 22. The cold air section 8 extends in particular from a cooling air inlet 20 to the heat exchanger 5. From the cold air section 8 branches off an engine cooling channel 23 to the motor 7 to cool it by supplying cold air. In the cooling air channel 22 is a third fan 24, which conveys cooling air from a cooling air inlet 20 through the air-air heat exchanger 5 to the cooling air outlet 21.

At the in Fig. 2 In the embodiment shown in which the dryer is a recirculating air dryer, the cold air for cooling the engine 6 comes from a separate cooling air duct. In this embodiment, therefore, as in Fig. 2 shown the additional use of a third blower 24 in the cooling air duct be useful. The for Fig. 2 not separately explained parts of the dryer correspond to those for Fig. 1 described parts and their functions.

Claims (7)

Dryer with a housing (1) and a drying chamber (3) for objects to be dried, a process air channel (2), in which a heater (10) for heating the process air and a first blower (6), a motor (7) for driving the drying chamber (3), a heat exchanger (5) and a cold air section (8) in the process air duct (2) or in a cooling air duct (22),
characterized in that the cold air section (8) branches off an engine cooling channel (23), through which the motor (7) can be acted upon with cold air. Dryer according to claim 1, characterized in that the cold air section (8) is located in the process air channel (2). Dryer according to claim 1, characterized in that the cold air section (8) is located in the cooling air channel (22). Dryer according to one of claims 1 to 3, characterized in that a partial air flow in the engine cooling passage (23) amounts to 30% of a total flow in the cold air section (8). Dryer according to one of claims 1 to 4, characterized in that in the engine cooling passage (23) is a second blower (25). Dryer according to claim 5, characterized in that the first blower
(6) and the second blower (25) form a double-flow blower (6, 25). Dryer according to claim 3, characterized in that in the cooling air duct (22) is a third blower (24).

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