1, Fittings used for connecting pipes are: flange, loose joint, pipe hoop, clamp, sleeve, throat hoop, etc2, Fittings change the direction of the pipe: elbow, bend pipe3, Fittings change the diameter of the pipe: reducing diameter (reducing pipe), reducing elbow, branch pipe, reinforcing pipe4, Fittings increase the pipe branch: tee, crossing5. Fittings for pipe sealing: gasket, raw material belt, thread hemp, flange blind plate, pipe plug, blind plate, head, welding plug6. Fittings for pipe fixing: clamp ring, tow hook, hanging ring, bracket, bracket, pipe clamp, etc