JPH0453560B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a temperature control device for controlling the drying temperature of a clothes dryer.

<Conventional structure and its problems> A thermostat is generally used for this type of temperature control in conventional clothes dryers, and when the temperature inside the drying drum exceeds a certain temperature, the thermostat is activated. A control system is used in which the heater is turned off and the heater is turned off. In terms of the drying process, the temperature at which this thermostat works is set at the point when the temperature rises to a certain extent with heating, after passing through the constant rate drying period when heat exchange is balanced and entering the lapse rate drying period. is common.

However, this control method lacks reliability because the drying temperature is easily influenced by outside air temperature. In other words, when the outside air temperature is high or the load is low, the temperature will rise rapidly after the constant rate drying period, causing deformation and alteration of synthetic fibers due to heat, and wrinkles. This is a contributing factor. Furthermore, this temperature setting has the disadvantage that it tends to become over-dry, resulting in unnecessary energy consumption.

<Purpose of the Invention> The present invention provides a method for controlling a heater in a clothes dryer so that the internal temperature of the drum does not always rise above the constant rate drying temperature or drop below it, regardless of the outside temperature. by doing,
It is an object of the present invention to provide a temperature control device that can reduce the adverse effects of heat on clothing and also save energy.

<Configuration of the Invention> In order to achieve the above object, the present invention includes a room temperature sensor that detects the room temperature in which the dryer is installed, an exhaust temperature sensor that detects the temperature of the exhaust gas exhausted from the rotating drum, and a constant rate dryer. a reference setting circuit that defines a maximum temperature rise in the vicinity of the temperature; a comparison circuit that compares the difference ΔT between the temperature sensed by the room temperature sensor and the temperature sensed by the exhaust temperature sensor with the maximum temperature rise Δt of the reference setting circuit; The comparison circuit stops the operation of the heater when the temperature difference ΔT of each sensor is greater than the maximum temperature rise Δt, and activates the heater when the temperature difference ΔT of each sensor is less than the maximum temperature rise Δt. This configuration is equipped with a controller that keeps the temperature almost constant. With this configuration, the drying temperature inside the rotating drum is not affected by room temperature and does not always rise above the constant rate drying temperature. This makes it possible to reliably control the temperature so that it does not drop significantly.

<Description of Embodiment> An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a clothes dryer incorporating the present invention. In FIG. 1, 10 is the body of the clothes dryer, and 12 is a rotating drum in which clothes to be dried are stored. A motor 14 installed at the bottom of the body 10 is connected to a belt 16 and
8 respectively drive a rotating drum 12 and an exhaust fan 20. Reference numeral 22 denotes a clothing inlet for throwing clothes into the rotating drum 12, and 24 denotes a door that can be opened and closed for the clothing inlet 22. 28 indicates clothing.

The arrows in FIG. 1 indicate the flow of clothes drying air due to the rotation of the exhaust fan 20. Air sucked in from an intake port 30 provided on the back side of the body 10 is sent to the front side of the body 10 below the rotating drum 12, and flows into the inside of the rotating drum 12 from the lower part of the clothes input port 22. Opening 3 at the bottom of the clothing input port 22
2 is provided with a heater 34, where the intake air is converted into warm air or hot air. Rotating drum 12
As the fan 20 rotates, the air that has dried the clothes 28 is discharged to the outside of the rotary drum 12 through the gap at the center of rotation of the rotary drum 12 and the filter 36, and is then discharged to the outside through the exhaust air cylinder 38. be done.

In the clothes dryer illustrated in FIG.
It is indicated by the reference numeral 40 in the figure. Of course, the room temperature sensor may be one that senses the entire outside temperature. When hot air is sent into the dryer body 10 without using the heater 34 for heating the drying air, the room temperature sensor 40 may be provided at any other suitable location where the room temperature can be detected. Further, the exhaust gas temperature sensor may be installed at an appropriate location within the exhaust wind cylinder 38, and is indicated by reference numeral 42 in FIG. however,
Since the exhaust temperature sensor is for controlling the temperature inside the rotating drum 12, the exhaust temperature sensor is designed to reflect the temperature inside the rotating drum 12 as much as possible.
It goes without saying that it is desirable to install it in a location close to 2.

FIG. 2 is a block diagram of a temperature control device according to the present invention. The output of the room temperature sensor 40 and the output of the exhaust gas temperature sensor 42 are applied to the input of a comparison circuit 48 via amplifiers 44 and 46, respectively, if necessary. The comparison circuit 48 outputs a signal ΔT indicating the temperature difference between the room temperature measured by the room temperature sensor 40 and the exhaust temperature measured by the exhaust temperature sensor 42. The output of the comparison circuit 48 is connected to one input of another comparison circuit 50, and the other input of the comparison circuit 50 is connected to the output of the comparison circuit 50. Output Δt of the reference setting circuit 52 that defines the maximum temperature rise
connects. Output of comparison circuit 52 (ΔT−Δt)
is applied to the heater controller 54, which stops the operation of the heater 34 when ΔT≧Δt (cuts off power supply in the case of an electric heater), and stops the operation of the heater 34 when ΔT<Δt.
Activate 4. The output of the exhaust temperature sensor 42 changes according to the activation and deactivation of the heater 34,
The internal temperature of the clothes drying temperature in the rotating drum is maintained at a constant value.

Although a configuration has been described in which the heater 34 itself as a heating source is used to stabilize the temperature during the lapse rate drying period, two types of heaters may be provided and used selectively: one for the constant temperature drying period and one for maintaining a constant temperature during the lapse rate drying period. Alternatively, a method may be adopted in which the applied current is changed depending on the purpose using the same heater.

Next, the operation will be explained. With the above configuration, as the heater 34 is energized, the temperature inside the rotating drum 12 increases and the clothes begin to dry. When drying the clothes enters constant rate drying, the moisture in the clothes evaporates and heat exchange takes place, so the exhaust temperature becomes constant and the difference between the exhaust temperature and the room temperature becomes constant. As the fabric dries, the moisture content decreases and the heat exchange balance is disrupted, causing the clothing to gradually begin to heat up. At this time,
The difference between the exhaust gas temperature and the room temperature gradually begins to increase. In other words, ΔT starts to increase. Comparison circuit 5
0 is the reference temperature Δt set by the reference setting circuit 52
T=(ΔT−Δt) is calculated from the value of and ΔT. At this stage, generally T<0, that is, the temperature change inside the drum is low, and the heater controller 54
The heater 34 is continued to be energized. When the lapse rate drying period begins and the temperature rise becomes larger than the reference setting value, T≧0, and the heater controller 54 cuts off the electricity to the heater 34 and stops the operation of the heater 34. By repeating this intermittently, the temperature inside the drum can be kept constant at or slightly higher than the constant rate drying temperature.

FIG. 3 is a graph showing the drying rate and drum temperature when drying clothes in both a dryer that uses conventional thermostat temperature control and a dryer that uses the temperature control device according to the present invention. . The dashed line shows the conventional example, and the solid line shows the example of the present invention. Note that the room temperature was 20°C. Curve A shows the drying rate curve, and curve B shows the drum internal temperature curve. Curve B becomes horizontal at approximately 50°C, which is the constant rate drying period. At point e, in the case of a conventional dryer, the temperature enters the lapse rate drying period as shown by the dashed line f, but in the dryer adopting the temperature control device according to the present invention, the temperature rises as shown by the solid line g. As shown, the heater is intermittently activated from point e onwards.
Even after turning on and off repeatedly, the temperature remains constant. On the other hand, at point e, the drying rate is already
At around 90%, it is almost dry, so
After this, even if the drying time becomes somewhat longer by keeping the temperature constant, the drying efficiency will not decrease. Furthermore, according to the present invention, since the temperature is kept constant, the problem of wrinkles, which is thought to occur in conventional devices when the temperature rises from point e, can be solved.

<Effects of the Invention> As described above, according to the present invention, the constant rate drying temperature is always kept constant regardless of the outside air temperature, so wrinkles that occur as the temperature increases during the decreasing rate drying period can be prevented, Helps save energy. In addition, since the heater is activated and stopped based on the temperature difference between the room temperature sensor and the exhaust temperature sensor, the drying temperature inside the rotating drum does not exceed the constant rate drying temperature even when the room temperature is high, which prevents clothes from getting damaged. Furthermore, even when the room temperature is low, the drying temperature inside the rotating drum does not drop significantly below the constant rate drying temperature, so it does not take a long time to complete the drying.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of a clothes dryer to which an embodiment of the present invention is applied, FIG. 2 is a block diagram of a temperature control device according to the present invention, and FIG. 3 shows a drying curve and a drum internal temperature curve for drying using the temperature control device of the invention. 10...Body of clothes dryer, 12...Rotating drum, 14...Motor, 16, 18...Belt,
20...Exhaust fan, 22...Clothing slot, 24
...Door, 28...Clothing, 30...Intake port, 32...
...Opening, 34...Heater, 36...Filter, 3
8... Exhaust wind cylinder, 40... Room temperature sensor, 42...
Exhaust temperature sensor, 44, 46...Amplifier, 48, 5
0... Comparison circuit, 52... Reference setting circuit, 54...
...Heater controller.

Claims (1)

[Claims] 1. In a clothes dryer equipped with a rotating drum for storing clothes and a heater for generating a breeze to be supplied to the rotating drum, a room temperature sensor detects the air temperature before heating by the heater, and a an exhaust temperature sensor that detects the temperature of the exhaust gas, a reference setting circuit that specifies the maximum temperature increase around the constant rate drying temperature, and a A comparison circuit compares the maximum temperature rise Δt of the reference setting circuit, and a comparison circuit stops the operation of the heater when the temperature difference ΔT of each sensor is greater than the maximum temperature rise Δt, and the temperature difference ΔT of each sensor is determined as the maximum temperature rise. A temperature control device for a clothes dryer equipped with a controller that operates a heater when the temperature is less than Δt to keep the temperature after constant rate drying almost constant.