National standards for marine expansion joints:

     1. The material of body, gland, A flange and short pipe of expansion joint is QT20-10, the material of bushing and packing seat is ZQAI 9-2, the material of type B short pipe is seamless steel pipe 10, and the sealing ring is oil-resistant rubber .

     2. There should be no pores or cracks on the surface of the sealing ring.

     3. Flange connection size according to GB 569

     4. After the common installation of expansion joints, a hydraulic test must be carried out. The test pressure Ps is 1.5min, and there should be no leakage.

     5. The products are accepted by the technical inspection part of the factory, and the orderer can conduct random inspections. The size of the batch and the number of random inspections in each batch are determined by both parties through negotiation.

     6. After the oil pipe expansion joint is installed in the workshop, the hydraulic test must be carried out. The test pressure is Ps=15kG/cm² for 5 minutes. If there is no leakage, it is qualified.

     7. Before packaging, the machined surface of metal parts should be coated with industrial vaseline, and other surfaces should be painted with paint.

     markup example

     Split expansion joints of DN 100 are marked as: expansion joint A100 CB*694-77

     The stuffing box expansion joint of DN300 is marked as: expansion joint B300 CB*694-77