DE3117749A1 - DRUM DRYERS, ESPECIALLY FOR USE IN LAUNDRY - Google Patents

Description

J0rgen Rasmussens Ventilation A / S, Nimbusvej 10, DK-2670 Greve Strand, Denmark

Drum dryers, _in particular_for_use2_in_laundries

The invention relates to a drum dryer, in particular for use in laundries.

Drum dryer with a drum, an air heating system, ducts for air inlet and air outlet, a fan and a filter are already known. The air from the outside flows through an air heating chamber into the chamber of the drum dryer, while the air from the system is released through a special exhaust duct aiU3i3trömL.

Attempts have been made to recycle some of the used air, however, os is difficult to remove the moisture from the air in an economical manner.

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The present invention relates to a drum dryer that is economical is because particular emphasis has been placed on retaining as many calories as possible from the exhaust, for whatever reason a fairly substantial part of the air used, after treatment in the other parts of the plant, is returned to the drum dryer chamber will.

The invention is based on the object of providing a particularly flexible and operationally reliable system for significantly reducing the energy requirement to create in a drum drying process.

This object is achieved according to the invention in that the drum dryer an air return device with mutually through .iutomatic Has control devices positively controlled exhaust air flaps into the open air or into the return duct, the flaps preferably have a mainly constant total flow area in every position.

According to the invention, the control device with one of the drum and the program control unit belonging to the air heating system cooperate. By setting this program control unit, you can let the system run at as high a temperature as the clothing can handle.

This control device can also have a moisture sensor mounted in the distribution chamber, so that the moisture i.qkei t controls the amount of return air in the distribution chamber.

In addition, the control device and the program control unit in the periods when the clothes in the drum are being changed and when the radiator is ineffective, for set up the exhaust air flap to open completely.

According to the invention, the mentioned condition can be achieved at the end of the dry period by starting the cooling of the clothing, before they can be removed from the drum, create.

Behind and following the flaps of the return duct can be Provide a double-suction centrifugal fan, preferably forward curved blades and one outside the return duct having mounted drive motor, wherein the shaft of the fan is arranged in bearings on the outside of the duct walls is. This centrifugal fan is particularly suitable for ensuring an even distribution of the air temperature over the flow cross-section in the following part of the return duct, even if cold fresh air is introduced into the canal.

According to the invention, a can be made directly at the end of the supply line of the fan both in relation to the main direction of the air flow as well as an air supply pipe arranged at an angle in relation to the axial direction of the fan. Due to the special The design and direction of this air supply pipe is an effective mixture of the cold supply air with the return air when they enter the double-suction centrifugal fan.

According to a particular embodiment of the drum dryer according to the invention is nach.dem centrifugal fan but before the air heating system An exchangeable filter, such as a double-layer line filter, is coupled in, with one layer being a coarse-meshed one Supporting net with preferably 20 to 40 meshes, in particular 30 meshes, per centimeter, and the other layer is a fine-meshed one Network with 60 to 100, preferably 80 meshes per centimeter.

Furthermore, according to the invention, one of the bearings of the fan shaft can be arranged in a rigid wall, while the second Storage is arranged on a thin, membrane-like, resilient wall section in the Rüchzuführkanal.

The invention is explained in more detail below with reference to the drawing. It shows

Fig. 1 is a side view of an embodiment of the drum dryer according to the invention,

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Figure 2 is a schematic plan view of the attachment of a centrifugal fan in the return duct and the air inlet pipe,

Figure 3 is a side view of the attachment and air inlet tube according to Fig. 2, but no fan is shown,

4 is a schematic view of an example of the structure Control devices, and

Fig. 5 shows the attachment of the control devices in connection with the Flaps and the attachment and connection of the hygrometer to the control devices.

The drum dryer shown in Fig. 1 has a drum 1 for Batch-wise holding of the laundry and a duct 2 for letting in air for the drum 1 and a duct 3 for letting out the used ones Air on. The used air is sucked out through the duct 3 by means of a fan 4. To channel 2 and the Fan 4 is connected to an air return device 8, Ln that the air taken in via duct 3 can be clocked back to channel 2 can be used again instead of being led away as exhaust gas. The air return device has an exhaust air flap 10 ins Free and one flap 11 in the return duct 14. These flaps are positively controlled by automatic control devices 15 and 16.

The flaps 10 and 11 preferably have a mainly constant total flow area in each position. All of the drag near the T-piece 13 of the air return device is therefore fairly constant.

The control devices 15 and 16 can be equipped with a drum J and to the air heating system 17 of the drum dryer Program control unit 18 cooperate, since the last-mentioned electrical signals to the control devices through a timing control unit 15 and 16 associated electrical, hydraulic or pneumatic parts 21, 22, 23, 24, 25, 26 and 27 can deliver. If the regulating parts are hydraulic or pneumatic, the part 21 can be a four-way valve which is controlled by an electric

Signal from the program control unit 18 is actuated. The control devices According to the invention can also be with moisture buttons 12a. and 12b provided in the distribution chamber 13 are mounted.

A drying process of items of clothing normally proceeds in such a way that the fans 4 and 14a and the air heating system 17 are activated after the wet clothing has been placed in the drum 1, after which the flaps 10 and 11 are activated by the control devices be adjusted so that a relatively small part of the exhaust gas is released into the open and the remainder is air is returned. After a predetermined drying time or after the garments have reached a certain degree of dryness the flap 10 is fully opened while the flap 11 is closed and the fan 14a is switched off. While the Flap 11 is closed, all air entering the drum is fresh air, i.e. air from the air inlet flap (the air inlet pipe) 20. During the intake of fresh air, the dried items of clothing are removed from the drum 1 and new wet items of clothing inserted.

During the intake of fresh air through the pipe 20, cooling takes place of the items of clothing dried in the drum 1 so that they are not exposed to heat damage.

Behind and following the flap 11 of the return channel is a mounted double suction centrifugal fan 14a, which is preferably has forward curved blades. He is made by someone outside of the return duct mounted drive motor 14b by means of a driven by the outer belt pulley. The shaft 14c of the fan is mounted in bearings 14d and 14e on the outside of the duct wall.

The air inlet pipe 20 is at the supply end of the fan 14a mounted in such a way that there is an acute angle with the main direction of the air flow, see the horizontal direction in FIG the axial direction of the fan. The flow conditions at the two suction ends on the centrifugal fan 14a are indicated by the arrows a and b. The flow conditions on the arrow a are such that there is a slight negative pressure at arrow a,

which causes fresh air to be drawn in through the pipe 20.

After the centrifugal fan 14a but before the air heating system A replaceable filter 25 is coupled in. For example, it can be a double-layer line filter, with one layer being a coarse-meshed one Support net with 20 to 40, preferably 30 meshes per centimeter, and the other layer is a fine-meshed net with 60 up to 100, preferably 80 meshes per centimeter. It is important that this filter be cleaned regularly. This also applies to one another double-layer filter 26 in channel 3.

It is important that the fan shaft 14c in its longitudinal direction is renewable. If the one shaft bearing 14e_ on a stiff The channel wall is fixed, the other shaft bearing 14d is mounted on a thin, membrane-like, resilient wall section 28 in the channel.

The invention can be varied in many ways without thereby deviating from the idea of the invention. The air return device can thus be built up from modules that can be put together and on different drum dryers and space conditions have it adjusted.

The module having the centrifugal fan can optionally be used with a cleaning door. This door can be opened by don form the entire module floor.

The control devices 15 and 16 can have pistons and piston rods, see FIG Parts 21 to 27 are driven.

Claims (9)

Patent claims: Drum dryers, especially for use in laundries, and with a drum, an air heating system, ducts for air inlet and air outlet, a fan and a filter, characterized in that it has an air return device with mutually through automatic control means has positively controlled exhaust air flaps into the open air or into the return duct, the flaps preferably in a mainly constant total pass area for each position exhibit. 2. Drum dryer according to claim 1, characterized in that the control device with one of the Drum and the program control unit belonging to the air heating system cooperates. 3. Drum dryer according to claim 1 or 2, characterized in that the SteuoreinrichLunq einon in the prescaler chamber Has mounted moisture sensor. ο Ί 1/749 4. Drum dryer according to claim 1, 2 or 3, characterized in that the control device and the Program control unit in the periods when the clothes in the drum are changed and where the radiator is ineffective, the exhaust air flap can be fully opened. 5. Drum dryer according to one or more of claims 1 to 4, characterized in that the state described in the above claim at the end of the dry period by The garments are created to begin cooling before they can be removed from the drum. 6. Drum dryer according to one or more of claims 1 to 5, characterized in that behind and following the flaps of the return duct, a double suction Centrifugal fan is provided, which preferably has forward curved blades and one outside of the return duct having mounted drive motor, the shaft of the fan in bearings on the outside of the duct walls is arranged. 7. Drum dryer according to one or more of claims 1 to 6, characterized in that immediately at the end of the supply line of the fan both in relation to Main direction of the air flow as well as an air supply pipe arranged at an angle in relation to the axial direction of the fan connected. 8. Drum dryer according to one or more of claims 1 to 7, characterized in that after the centrifugal fan but before the air heating system a replaceable Filter, such as a double-layer network filter, is coupled in, with one layer being a coarse-meshed support network with preferably 20 to 40 meshes, in particular 30 meshes, per centimeter, and the other layer is a fine-meshed one Network with 60 to 100, preferably 80 meshes per centimeter. 9. Drum dryer according to one or more of claims 1 to 8, characterized in that one of the bearings of the fan shaft is arranged in a rigid wall is, while the second bearing on a thin, membrane-like, flexible wall section in the return channel is arranged.