Spiral pipe hydraulic test principle: 
Spiral hydraulic test machine during pressure test, first by end sealing device to seal both ends of the test pipe and inject low-pressure water, process water discharge in the air through the exhaust valve within the tube, after the low-pressure water filled by pressurization device to inject high-pressure water pipe pressurized until the required test pressure. 

After reaching the prescribed test pressure at the stipulated time packing, spiral if no leakage, deformation phenomena in the pressure test, then be depressurized. Then open end sealing device, low-pressure water discharge will be sent to the test coil visual inspection stations to check for suspicious penetration. According to the standards of the pressure curve of pressure testing process adopts automatic recording system records.