When installating  the pipeline, you should have to wait until the moment when a momentary pressure is higher than the operating pressure to select the joint. And the flange connected to flexible rubber joints should be  valve flange or flanges in line with the standard of GB / T9115.1 (RF) .

 

When installing flexible rubber joint, the screw bolts should be toward the outer of joint ,the bolts of every flange should be tightened by increasing pressure repeatedly evenly  to prevent flattening.  Screwed fittings should use standard wrench uniform force to tighten , do not use afterburner rod afterburner slide wire to make the union , slippery edge and fracture , and to regularly check , in order to avoid causing loose off the plate or seepage.