At present, the mechanical excavation of tunnels mainly includes two types of shield technology: earth pressure balance and mud-water balance. The greater risk of shield construction in soft soil is that the pressure on the face of the tunnel is not Stable and mutation. Maintaining the stability of the tunnel face through the compressed air automatic adjustment and holding pressure control system (shield machine air automatic holding pressure system) is currently one of the commonly used methods in shield equipment. During construction, air control technology is used to control the tunneling surface The pressure is automatically adjusted and controlled so that it is always in a balanced state to ensure the stability of the excavation surface during shield tunneling, thereby ensuring safe and efficient shield construction. The air automatic pressure maintaining system of the shield machine is a single parameter fixed value closed-loop automatic control system with the soil bin or mud bin as the controlled object and the pressure in the bin as the controlled parameter.

The proportional integral (PI) regulation law is realized through pure pneumatics. The proportional action can speed up the control process and reduce the dynamic deviation; and the integral action can eliminate the residual error. The PI parameter adjustment range is large, the accuracy is high, and the adjustment is convenient. The adjustment control accuracy is up to ±1%.
Based on the force balance working principle, with feedback design concept, because of the small displacement, small friction loss, the adjustment instrument response is sensitive, high precision, compact structure, not easily affected by environmental temperature, and strong anti-interference ability.
The output signals of the pneumatic regulating instrument are all amplified by the power amplifier in two stages of pressure and flow, which can be transmitted over a long distance.
The pressure holding system comes with a given pressure, actual pressure indicating instrument, and a control instrument output signal indicating instrument, realizing real-time monitoring and facilitating on-site adjustments.
It has a "hand/auto" non-disturbance switching function for on-site debugging and emergency treatment.
The pneumatic adjustment instrument has a full metal shell with high protection level and is suitable for harsh on-site working conditions.
Using dedicated calibration and testing equipment, accurate calibration according to customer requirements.
Customized design and development can be carried out according to the special needs of customers and working conditions and environmental requirements.

Professional and directional engaged in the design and development of shield pressure holding system;
Customized design can be made according to shield machine construction and supporting needs, such as: mobile shield pressure holding system;
Provide 24-hour technical consultation, model selection and quotation services;
Original maintenance, testing, and calibration test equipment to ensure service and product quality;
Hundreds of sets of pressure-holding system adjustment and maintenance project experience, we design products, and are familiar with the site at the same time.