1. Factors affecting installation quality

(1) The clamp shall be free of air hole, sand hole, shrinkage crack and other defects.

(2) The material and performance of the sealing ring must meet the requirements. There shall be no bubbles, impurities, cracks, uneven concave convex defects on the sealing surface. Aging rubber ring shall not be used.

(3) Theoretically, the moving distance of the clamp ring in the clamp is half of the expansion amount of the joint, and the actual amount should be measured. If it can not reach the actual amount, it can not meet the expansion amount requirements of the pipeline. In order to improve the sealing effect, the left and right end pipes are matched with the clamp before leaving the factory. In practical engineering, it is not suitable to use ordinary pipe to directly replace the end pipe. Moreover, there are certain requirements for the perpendicularity between the end face of the end pipe and the axis and the flatness of the end face itself. If the size is not standard, the expansion of the joint will be greatly reduced, which can not meet the use requirements（ 4) The dimension of end pipe diameter should be selected with positive deviation, otherwise the compression force of clamp on sealing ring is not enough, which will affect the sealing effect of joint.

2. Precautions during installation

(1) The distance L between the snap ring and the end tube should be controlled. The control of l should be combined with the instruction manual. When the gap between the two pipe ends is the smallest, the snap ring should be just close to the inclined plane.

(2) When the snap ring position is determined, the gap between the two pipe ends should be determined by calculation according to the elongation of the pipe and the ambient temperature during construction. Ensure the deviation of dimension during construction.

(3) Under the premise of a certain moving distance, the larger the weld height and width of the clasp and the end pipe, and the Perpendicularity Error of the clasp plane and the end pipe axis, the smaller the expansion of the joint, and the worse the use effect.

(4) The spatter impurities during the welding of end pipe and snap ring affect the sealing of end pipe. The welding slag on the sealing surface shall be removed before installation to ensure the sealing effect.

In addition, because the grooved pipe fittings are finished products, the operation space required on site is small, which can truly realize the installation against the wall and corner, and the operation difficulty is greatly reduced, so as to save the floor area and beautify the effect of pipeline installation. The original characteristics of the pipeline are not affected by the connection of grooved pipe fittings. Only a groove is extruded on the outer surface of the pipeline to be connected by the grooving machine without damaging the inner wall structure of the pipeline. This is the unique technical advantage of grooved pipe fittings connection. If the traditional welding operation is adopted, many pipes with anti-corrosion coating on the inner wall will be damaged. Therefore, the specification stipulates that galvanized pipe, plastic lined steel pipe, steel plastic composite pipe, etc. shall not use welding and flange connection, otherwise secondary treatment is required.