The composition of the temperature control system mainly has the following three forms:

The first method: temperature control meter + AC contactor (or SSR) control method. The temperature sensor installed on the heat tracing pipe (or equipment) transmits the detected temperature to the temperature control instrument. The temperature control instrument compares the detected temperature with the set temperature, and then decides whether to start the electric heating cable. This control mode is a switch output mode, which is a discrete control mode. To avoid frequent start and stop, the temperature control instrument parameters need to set a hysteresis, and the temperature of the pipeline is kept within a certain range.

The second method: temperature control instrument + thyristor control mode. The temperature sensor installed on the heat tracing pipe (or equipment) transmits the detected temperature to the temperature control instrument. The temperature control instrument compares the detected temperature with the set temperature, and then outputs a 4-20 mA current signal to the temperature control instrument. The thyristor controls the thyristor output voltage, thereby adjusting the heat tracing temperature of the electric heating cable. This control mode is an analog output mode, which is a continuous control method. The PID closed loop control mode is used to intervene in advance to achieve the purpose of smooth control.

The control accuracy of this control mode is ± 1 °C.

The third method: PLC or SCM control system. The PLC control system is a relatively advanced control system. It can not only implement the control in the above two cases, but also has functions that they cannot achieve, such as timing functions, reviewing historical data functions, and remote communication control functions. The working principle of the PLC system is that the temperature sensor installed on the heat tracing pipe (or equipment) transmits the detected temperature to the PLC analog module, and a specific program is written in the PLC. After analysis, the signal output from the output terminal control the AC Contactor or SSR. This control mode can be switch output mode or analog output mode. The single-chip microcomputer control method is similar to the PLC system, but the single-chip microcomputer control is flexible and the installation space is small.

The electric heat tracing control system can also realize remote control or communication, and the acquisition communication module is added inside the intelligent temperature control distribution box, and it is connected with the remote DCS system through the communication protocol recognized by the two devices. The operating state and real-time temperature of each circuit can be visually displayed on the DSC system through the screen, it also can control the start and stop of the electric heating cable.

Special non-explosion-proof distribution box (cabinet) for electric heat tracing

Special non-explosion-proof distribution box (cabinet) for electric heat tracing

Type number nomenclature:

Function of distribution box:

1) Built-in miniature circuit breaker, protector, contactor, signal indicator and other components, with overload, short circuit leakage protection and other functions.

2) Special requirements can be made, such as adding ammeter, voltmeter and various digital instruments.

3) The distribution box with temperature control system can automatically adjust the temperature, digital display temperature, high temperature alarm, alarm and control by remote signal.

4) The distribution box has its own dehumidification heating function, which can be used outdoors in the cold winter to ensure the normal operation of the electric heating system.

Technical parameter:

1) Rated voltage: AC220V, AC380V, AC660V

2) Rated current: 10A ~ 250A per circuit

3) Control temperature: 0 ~ 800 °C

4) Insulation resistance: ≥ 5MΩ

5) Protection level: IP55/IP65

6) Application environment: ambient temperature -30 ~ +60 °C, relative humidity ≤ 90%.

Characteristics:

1) Non-explosion-proof distribution box is suitable for electric heat tracing products in nonexplosion-proof places;

2) The material is generally made of cold-rolled steel or stainless steel, with wall-mounted or floor-mounted cabinet structure;

3) Built-in leakage short-circuit protector and signal indicator, single-phase/three-phase power supply; molded case circuit breaker, leakage circuit breaker, signal indicator and other electrical components can be built-in according to the requirements, and digital temperature control instruments and Intelligent control also can be set with.

4) When the temperature measurement distance is long, the input signal needs to select the 4-20 mA analog signal to connect with the temperature control instrument to ensure the accuracy of the displayed data.

5) Rain cover shall be required if it is installed outdoor.

Special Explosion-proof Distribution Cabinet for Electric Heat Tracing

Type number nomenclature:

Function of distribution box:

1) Explosion-proof power distribution box is built in miniature circuit breaker, protector, contactor, signal indicator and other components, with overload, short circuit leakage protection and other functions.

2) Special requirements can be made, such as adding ammeter, voltmeter and various digital instruments.

3) Explosion-proof distribution box with temperature control system can automatically adjust temperature, digital display temperature, high temperature alarm, alarm and control by remote signal, button is set outside temperature control instrument for easy operation.

4) Explosion-proof power distribution box has its own heating function, which can be used outdoors in cold winter to ensure the normal operation of the electric heating system.

Technical parameter:

1) Rated voltage: AC220V, AC380V, AC660V

2) Rated current: 6A ~ 100A per way

3) Control temperature: 0 ~ 800 °C

4) Insulation resistance: ≥ 5MΩ

5) Protection level: IP54/IP56/IP65

Application:

1) Suitable for areas of hazardous gas mixtures: division 1, division 2;

2) Suitable for temperature group of explosive gas mixture: T1 ~ T5;

3) Applicable to classification of explosive gas mixture hazard: IIA, IIB, IIC.

4) Suitable for flammable dust hazardous places

Characteristics:

1) Aluminum alloy die-casting shell, surface high-voltage electrostatic spray molded surface;

2) The explosion-proof distribution box is a composite structure, the switch box adopts an explosion-proof structure, the busbar and the outlet box adopt an increased safety structure, and the whole adopts a modular structure, and various circuits can be selected and combined;

3) Widely used in explosion-proof areas such as oil storage areas, chemical plant areas, and gas areas.

Outlook and installation:

Remote control system:

According to the needs of the customer's site, our power distribution system can achieve remote temperature control. Through the remote control system, you can learn the field operation and modify the parameters (such as temperature setting, hysteresis, etc.).

There are variety of ways for remote control systems, such as DCS systems, PLC systems, and more.

Communication interface has RS232, RS485, RJ45 and so on.

Communication protocol TCP/IP, Modbus, etc.