Chiller introduction part 3

1. Control principle The control system is a closed-loop negative feedback system: the temperature measurement element (thermocouple or thermal resistance) transmits the detected temperature signal (mV) to the intelligent PID temperature controller; the temperature controller accounts for a fixed period of time. Empty ratio, output DC15V, 20mA high level, drive zero-crossing non-contact controller to control the output power of the oil heater.

2. The control system constitutes a centralized control electric control cabinet: the control cabinet panel is equipped with display, adjustment, operation, alarm indication and other devices; internally equipped with power supply, protection, drive, signal conversion and other devices.

3. Protection device: a. Over-temperature alarm, when the oil temperature at the outlet of the oil heater exceeds the set temperature value of the temperature regulator (generally set above the process temperature and below the allowable use temperature of the heat transfer oil), it will be issued on the electric control cabinet Sound and light alarm signal, and the system automatically stops heating. Notice! The circulating oil pump cannot be stopped at this time. b. Expansion tank low liquid level alarm: When the system requires low liquid level alarm protection function, install a float level controller on the expansion tank. When the heat transfer oil in the expansion tank is lower than the lower limit liquid level, the level gauge will send out Control signal, sound and light alarm message will be sent out on the electric control cabinet. After the alarm, the expansion tank should be filled with heat transfer oil immediately to make it reach the normal liquid level. c. Regularly check the outlet pressure gauge of the circulating oil pump: this pressure gauge is one of the indispensable safety accessories in the system. Use this meter to measure the working pressure of the circulatory system, monitor and control the operation of the system. If the system requires an overpressure alarm protection function, an electric contact pressure gauge should be used. When the pointer of the pressure gauge coincides with the upper and lower limit positions, an alarm signal will be issued. Notice! During the use of the heater, the system pressure must be monitored frequently; the pressure gauge must be replaced in time if it fails or is damaged.

4. The electrical control adjusts the main power supply of the heating body of the heating part. The solid state relay is used to trigger the switch circuit at zero crossing, which is suitable for frequent switching and has no interference to the power supply network.

5. Accurate temperature control The temperature control instrument adopts PID self-tuning intelligent temperature control instrument, which can control the operating temperature within the range of ± 2°C relative to the set value.