The basic working principle of the hydraulic press is Pascal's law. The steel pipe conveying device is responsible for the in and out of the steel pipe. The water system is responsible for filling the steel pipe with water during the hydrostatic test. The oil system is responsible for controlling the head to achieve the pipe during the hydrostatic test. At the end of oil-water pressure balance, the control system is responsible for the automatic operation control of the entire equipment, the automatic preservation of test data and the management of historical data.

The working principle of the control system is mainly divided into the following parts:

1. The engineer sets the control parameters;

2. According to the process requirements, the operator modifies the transfer process parameters;

3．The operator uses the console to control the steel pipe conveying device through PLC to complete the conveyance of the steel pipe;

4．When the steel pipe reaches the test position, the operator completes the pipe end seal and pre-filled water in the pipe through the man-machine interface, and starts the hydrostatic test of the steel pipe;

5．The water pressure sensor detects the water pressure value in the steel pipe in real time, sends it to the PLC for signal analysis and processing, calculates the oil pressure control signal according to the oil-water balance principle, and outputs it to the power drive unit of the electro-hydraulic proportional valve to control the action of the electro-hydraulic proportional valve. , And then control the oil pressure value of the end of the pipe to achieve oil-water balance, complete the hydrostatic test of the steel pipe. The signals detected by the oil pressure sensor and the water pressure sensor are simultaneously sent to the industrial control machine in real time, and the operator monitors the test process in real time through the monitoring screen.