A pure pneumatic solution for solving the pressure balance of shield tunneling machine bentonite system, which includes:

1. PI pneumatic control instrument/base instrument

The main function of the logic operation unit is to compare the deviation between the actual value and the actual set value through the PI controller, and adjust the output signal based on the size of the deviation value;

2. Pneumatic control valve

A top guided single seat regulating valve has the advantages of simple structure, large flow rate, and reliable performance;

3. Pneumatic Positioner

The pneumatic control element controls the valve position by operating the pneumatic actuator after receiving an air pressure signal of 0.2-1.0 bar;

4. Pneumatic pressure transmitter

Pneumatic measuring element, which measures the air pressure parameters of the process and converts them into standard signals (0.2-1bar) for output;

5. Self operated regulating valve

An energy-saving universal pressure control valve that uses the pressure of the medium itself as the driving force to drive the actuator to adjust the flow rate of the valve core to control stable pressure;

6. Air source processing components

Effectively remove solid impurities, water droplets, and dirty oil droplets from compressed air;

7. Pipeline connection accessories, fixed brackets, etc;

For example, in the bentonite system of shield tunneling machines, the pressure inside the bentonite tank is constantly changing. The pneumatic pressure transmitter measures the pressure inside the tank and converts it into a universal signal, which is transmitted to the PI pneumatic control instrument. After receiving the measurement signal, the PI pneumatic control instrument performs logical calculations and outputs a control signal to the pneumatic positioner to adjust the opening of the pneumatic control valve. By adjusting the opening of the inlet/outlet control valve, the pressure inside the tank is maintained stable.

This plan is also suitable for vegetable preservation, medical oxygen storage, and other conditions that require precise pressure control.

1. High control accuracy;

2. Reliable work;

3. Strong anti-interference ability;

4. Safety explosion-proof;

5. Easy to maintain;