JPS60235216A - Temperature control method of heating device - Google Patents

Abstract

PURPOSE:To eliminate the overheat state to prevent control defects due to reduction of the flow rate of a fluid by stopping the supply of a supply heat source if the output of a flow rate detector which detects the flow rate of the fluid flowed into a heater is lower than a set value. CONSTITUTION:This system concists of an electric heatig device 1 using an electric heater, a temperature controller 2 which detects the exit temperature of the fluid and controls this temperature by an electric heater power switch, an overheat preventing detector 3, and a flow rate detector 4. The temperature rise of the temperature detector 3 and the reduction of the flow rate of the flow rate detector 4 are added to start conditions of a main power switch, and the main power switch of the air heating device 1 is broken to prevent accidents of the local overheat due to a drift of air if the flow rate of the fluid to be heated such as air is reduced. The temperature controller 2 prevents control defects which are caused if an accurate temperature is not detected when the fluid is not flowed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to temperature control of a heating device that heats a fluid such as gas.

[Background of the invention]

The technique of comparing the output of a temperature detector that detects the temperature of a heated fluid with a target value and adjusting the temperature control means of a heating device so as to eliminate the deviation detected by this comparison is well known. . This is disclosed, for example, in "Electrical Engineering Handbook" published by the Institute of Electrical Engineers of Japan (April 10, 1970), page 1570.

Now, in a heating device for fluid such as gas, specifically air, if the flow rate of the fluid flowing into the heating device decreases, an overheating state will occur in a localized area, and it is necessary to install a temperature sensor. Depending on the location, there may be situations where control is not possible.

[Purpose of the invention]

An object of the present invention is to prevent poor control due to a decrease in fluid flow rate.

[Summary of the invention]

The present invention provides a supply heat source (power supply) to the heating device when the output of a flow rate detector that detects the flow rate of fluid flowing into the heating device becomes less than or equal to a set flow rate.

The feature is that the supply of steam, etc.) is stopped.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIG.

1 is an electric heating device using an electric heater, 2 is a temperature controller that detects the flow outlet temperature and controls the fluid outlet temperature by opening and closing the electric heater power switch, and 3 is a temperature for preventing overheating of the electric heating device 1. It is a detector. Furthermore, a flow rate detector for detecting the flow rate of air, which is the fluid to be heated in the electric heating device 1, is provided in the fluid inlet piping as shown in the figure.

By setting the conditions for the increase in humidity in the temperature detector 3 and the decrease in the flow rate in the flow rate detector 4 to be included in the activation conditions for the main power switch, when the flow rate of the fluid to be heated such as air decreases, the main By shutting off the power switch, it is possible to prevent accidents caused by extreme overripe due to air drift. Also,
The temperature adjustment unit 2 has the effect of preventing control failures due to inaccurate temperature detection when fluid is not flowing.

FIG. 2 shows another embodiment, in which 5 is a steam heating device using steam, and the fluid outlet temperature is determined by a temperature controller 2.
By opening and closing the automatic control valve 6, the amount of steam is adjusted and controlled to be constant. By putting the flow rate reduction condition of the flow rate detector 4 into the opening condition of the automatic control valve 6, and by putting it into the effective condition for preventing control failures, there is an effect of preventing control failures.

〔Effect of the invention〕

As explained above, according to the present invention, since the supply of the heat source is stopped when the flow rate falls below a set value, overheating does not occur, and control failures can be prevented.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the invention, and FIG. 2 is a diagram showing another embodiment of the invention. l... Electric heating device, 2... Temperature controller, 3... Temperature detector for overheat protection 111, 4... Flow rate detector, 5... Steam heating device, 6・・・・・・To Akio Takahashi, patent attorney and agent for automatic control valves, Mr.

Claims (1)

[Claims] 1. Temperature control of the heating device, which calculates a manipulated variable based on the comparison result between the output of a temperature detector that detects the temperature of the heated fluid and a target value, and adjusts the temperature adjustment means of the heating device using the manipulated variable. In the method, the temperature of the heating device is characterized in that the supply of the heat source to the heating device is stopped when the output of a flow rate detector that detects the flow rate of the fluid flowing into the heating device becomes equal to or less than a set flow rate. Control method.