Foreword: the cornerstone of quality
In the precision manufacturing system of DG series horizontal multistage centrifugal pump, the pressure bearing capacity and sealing performance of components are the core indexes to ensure the long-term stable operation of the equipment. In order to ensure the absolute reliability of products under high pressure, we have formulated strict test specifications for pressure seal in suction section. The purpose of this process is to eliminate potential defects through standardized testing methods and ensure that each factory equipment has excellent sealing quality.
The first stage: tooling preparation and pretreatment
Surface treatment and installation: before installing the pressure test boring plate, the external thread of the hose joint must be pretreated and the raw tape should be evenly wound to ensure the tightness of the thread pair.
Precise positioning and fastening: accurately insert the O-ring into the slot of the stuffy plate, and closely fit the flange face of the stuffy plate with the end face of the suction section. Tighten bolts and nuts symmetrically and evenly with torque tools to ensure balanced stress and prevent sealing failure caused by flange surface deformation.
Auxiliary plugging: The remaining screw holes in the suction section that did not participate in the test should be sealed and fastened with plugs wrapped with raw tape to construct a complete closed cavity.
The second stage: pressure test and pressure monitoring
Water injection and exhaust: completely fill the cavity of the suction section with water, and exhaust at a high point to ensure that there is no air residue in the cavity, so as to avoid false pressure keeping or pressure reading deviation caused by air bags.
Connecting and boosting: Connect the pressure pump and hose connector, and start the pressure test pump. The operator should closely monitor the reading of the pressure gauge and steadily raise the system pressure to the test pressure value specified in the suction section of this model.
Strict pressure keeping: After the pressure reaches the set value, enter the pressure keeping stage for 10 minutes. During this period, it is forbidden to drop the pressure,and the pressure gauge pointer should be kept stable.
The third stage: leak detection and determination
Detection means: During the pressure maintaining period, the weld seam, casting body and all connecting flange surfaces of the suction section are visually inspected in all directions with a strong flashlight.
Acceptance criteria: the only criterion for judging qualified is "no trace of leakage". Any tiny drops of water, water mist or signs of wetness are considered unqualified.
Safety warning: Safety operation procedures must be strictly observed during the whole test to prevent high-pressure water jet injury.
Conclusion: closed-loop management
Release: The suction section that has passed the test can be transferred to the next assembly process.
Interception and retest: The unqualified parts will be isolated, and the above-mentioned whole-process test will be re-performed after repair until they fully meet the sealing requirements.
Post time: Jul-09-2026