JPS6096300A - Control of dryer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of controlling a dryer for drying clothes and the like with hot air.

Conventional structure and problems Generally, when drying clothes, the drying time varies depending on the amount and type of cloth, so conventional dryers use a timer that allows the user to set the time at a time that the user deems appropriate based on past experience. It was set.

Page 2 However, if you set the timer incorrectly, the fabric could become over-drying, damaging it or leaving it undried. In addition,
It would be uneconomical if it became too dry. There is also a method of detecting dryness by detecting the resistance value of the cloth, but since the resistance value of the surface of the cloth is detected with electrodes, there is a risk that the cloth will not dry properly if the cloth is thick. If the amount was small, the cloth may not touch the electrode, and in this case dryness could not be detected. Furthermore, since the method detects the surface resistance of cloth, it is necessary to detect a very high resistance value, which poses some problems with the circuit.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional problems, and provides a dryer control method that can inexpensively detect a specified drying rate regardless of the type of fabric or the degree of fabric. The dryer control method of the invention stores the time when the rate of change in exhaust gas temperature reaches a specified value, calculates the rate of change in exhaust temperature even after the rate of change reaches the specified value, If the rate of change becomes negative, it is determined that the temperature has increased due to an abnormality such as cloth entanglement, and the rate of change has reached the specified value.
Ignoring the time when the rate of change of the exhaust gas temperature reaches the specified value,
Wait until the rate of change reaches the specified value again. Then, when the rate of change does not become negative after reaching the specified value, the specified drying rate is detected. With this method, malfunctions will not occur even if the temperature rises due to some cause such as entanglement of cloth, and a specified drying rate can be achieved.

DESCRIPTION OF THE EMBODIMENT FIG. 1 shows a block diagram of an embodiment of the present invention. 1 is an exhaust temperature detection device that detects the exhaust temperature of the dryer. 2 is an operating time counting device that counts the operating time of the dryer from the start of operation. 3 is an arithmetic and control device that receives the output of the exhaust gas temperature detection device 1, calculates temporal changes, and calculates the rate of change. Further, this arithmetic and control device 3 receives the output of the operating time counting device 2, calculates the operating time by putting it into a prescribed function, compares the rate of change in the exhaust gas temperature with the calculated value of the operating time, and uses the result to determine whether the dryer The heater 4 or motor 5 is stopped or continues to operate.

FIG. 2 shows how the exhaust temperature changes as drying progresses. During the period t1, the amount of heat applied during the preheating period does not contribute much to drying, and the exhaust gas temperature rises rapidly. During the period t2, the amount of heat given during the constant rate drying period is taken away by the latent heat of vaporization of moisture, and the exhaust temperature becomes constant. This is the most efficient way to dry. Period t3 is a lapse rate drying period, in which the cloth is almost dry and the exhaust temperature increases.

Figure 3 shows the rate of change curve of exhaust gas temperature. P' in Figure 3
The point is the point where the drying rate shifts from the constant rate drying period to the decreasing rate drying period at approximately 90% point. Point P' corresponds to point P in FIG.

This point P' is a function of the operating time t of the dryer determined in the experiment. It is on ΔT/Δt, = −At+B.

At is a change in operating time, and ΔT is a constant, and exhaust temperatures A and B that have changed during the change in operating time Δt are constants.

Page 6 Therefore, if the drying rate is detected when the rate of change in the exhaust gas temperature exceeds the detection line 6 determined by the function of the operating time t -At-)B except during the preheating period t1, the drying rate will be , it becomes approximately 90 inches at the time of transition from the constant rate drying period to the decreasing rate drying period.

It should be noted that even if we experimentally find a constant value C instead of At-1-B based on the operating time and detect the drying rate when the rate of change in exhaust gas temperature reaches the constant value C, the drying rate of the cloth Somewhat 9
Regardless of the type, a drying rate of approximately so% can be obtained. If a drying rate of 90% can be detected, a delay time is determined based on the time it takes for the drying rate to reach 90%, the operation is delayed by a specified time, and a drying rate of 100% can be obtained.

FIG. 4 shows a case where the exhaust temperature changes due to entanglement of the cloth. The convex portion 7 of the exhaust gas temperature T is the exhaust gas temperature change caused by the entanglement of the cloth. The rate of change in exhaust gas temperature in this case is shown in FIG.

P1 is the reference line 8 for determining the magnitude of the rate of change in exhaust temperature ΔT/Δt, that is, the point at which ΔT/Δt=-At+B or more.
', P1' is detected every 6 bags before detecting the true drying rate detection point P2', and a signal indicating 90% detection is generated even though the drying rate is not yet dry.

However, when the exhaust temperature increases due to tangled cloth, the temperature inevitably decreases because the tangled cloth is loosened or the tangled cloth is moved to another location. Therefore, at this time, the rate of change in exhaust gas temperature becomes negative (point 9 in FIG. 6).

When the rate of change in the exhaust gas temperature becomes negative, the point in time when dryness has already been detected is removed and the detection operation is performed again.

That is, 9o% detection was performed at P,', and then the operation moved to 100% detection after driving for a specified time, but since the rate of change became negative at 9 points, P1' was skipped and the detection operation was performed again. P
Detect 2' and detect 90% OP2' After detection, calculate the rate of change in exhaust temperature until the drying rate reaches 10%,
Monitor to see if it becomes negative.

If it is not negative, the operation that was in the drying rate 100% detection after P2' is the first one! , then continue to detect the drying rate of 100%.

If the rate of change becomes negative after P2' is detected, 227 points are ignored and the 90% detection operation is started again.

As shown on page 7 and above, this method calculates a predetermined drying rate from the rate of change in the exhaust temperature of the dryer, which prevents malfunctions caused by clumps of cloth and enables reliable dryness detection at low cost.

Effects of the Invention The dryer control method of the present invention detects dryness by determining the rate of change in the exhaust temperature of the dryer and detecting whether the rate of change in the exhaust temperature becomes negative after the rate of change reaches a specified value. This prevents malfunctions caused by clumps of cloth, and provides reliable dryness detection at low cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a dryer control method showing an embodiment of the present invention, FIG. 2 is a dryer exhaust temperature change characteristic diagram, and FIG.
The figure is an exhaust temperature change rate characteristic diagram calculated from the exhaust temperature change in Figure 2 to the rate of change per unit time. Figure 4 is an exhaust temperature change characteristic diagram during abnormal conditions. Figure 6 is the exhaust temperature change rate in Figure 4. FIG. 4 is an exhaust temperature change rate characteristic diagram in which the change is calculated as a change rate per unit time. 1... Exhaust temperature detection device, 3... Arithmetic control device. Figure 1 'Jz, y teeth 11 straw l i ears

Claims (1)

[Claims] After the rate of change in the exhaust gas temperature of the dryer reaches a specified level, it is detected whether the rate of change in the exhaust temperature becomes negative, and if it becomes negative, the time at which the rate of change in the exhaust temperature reaches the specified level is detected. A dryer control method that ignores the change rate and measures the time it takes for the rate of change in exhaust gas temperature to reach a specified level again, and when it does not become negative, detects the specified drying rate.