2,Flange double sphere flexible rubber joint and the flange are connected when install,screw bolts should be toward the flange lateral,to prevent the thread tip scratch joint body when the ball swelling deformation,and each end surface of the flange bolts should be gradually symmetric compression step by step,required the bolt tightness as same as possible, If under harsh conditions,in addition to the flat gasket,also can add spring gasket, to prevent the nut loosening.

3.If the use of arched or high arc rubber joints,(because of the six corners of the bolt is difficult to pass through the flange hole), must use a double headed bolt,and to minimize the ball end of the protruding part,so as to avoid the expansion of the sphere compression was crushed, and the rubber joint early damage.

4.when the rubber joint in the water (oil) pump or under the condition of the frequent conditions,to reduce the rubber joint length of the tensile and compression is too large to the pump and pipe,should increase the limit device at both ends of the flange.

5.the diameter is above dn1000mm,for easy to install and reduce the labor intensity,should in the end of the flange make a short pipe, when rubber joint and the short pipe connected with the other end pipe,then welding the short pipe and the long end of the pipe.

6.To facilitate for short tube welding deformation caused by the radial deviation ， before welding should temporary welding use metal bar or other appropriate strength to both ends of the pipeline,make the rubber joint and the flange formed at the connecting point between the rigid body,after short completion of welding,removed the welding material,in order to make rubber joints in  nature state.

7.When the metal connector and the flange welding,remember to cover the rubber joint welding place with the cover.So as to avoid the welding burned rubber sphere.