1. Weld the flange to the pipe and cool it to the ambient temperature before installing the valve on the flange. Otherwise, the high temperature generated by welding will affect the performance of the elastic seat.
2. The edge of the welded flange must be lathed until the surface is smooth to avoid damage to the elastic seat during valve installation. Flange surface must be completely free from damage and deformation, remove all dirt dust and foreign matter, to avoid liquid leakage of valve and flange interface.
3. Clean the flange and the inner cavity of the pipe to thoroughly remove the sputtering, peeling scale and other foreign bodies left by welding.
4. When installing piping between valves, accurate alignment of the center of the upstream and downstream piping is essential for trouble-free operation. The imprecise center points shown in Figure 1 must be avoided.
5. When installing the valve, fix the positioning bolt under the pipe at the same height to provide support. And adjust the distance between flanges until the distance between the two sides of the valve body is about 6-10mm. Remember that valve can only be opened from closed position to 10° position here.
6. Insert the two bolts into the lower guide rod of the valve and install them carefully so that the flange surface does not damage the elastic seat. (See Figure 2)
7. Then place the other two bolts into the guide bar above the valve to ensure accurate center positioning between the pipe and the valve.
8. Open the valve three times to check whether the contact between the valve plate and flange is not smooth.
9. Remove positioning bolts and place all bolts around body for alternating diagonal tightening (see FIG. 3 and FIG. 4) until flange touches body. Please refer to the table below for recommended torque values.
10. Provide a support for valve when installing actuator to avoid twisting of valve neck and reduce friction between valve and pipe.
11. Do not step on valve neck or valve handwheel.
12. Do not install DN350 or larger valves upside down.
13. Do not install butterfly valves directly on check valves or pumps as this may cause damage when touching the valve plate.
14. Do not install valves on the downstream side of the elbow and taper pipe, or calibrate valves when the flow rate changes. In this case, it is recommended to install the valve at a distance of approximately 10 times the nominal diameter of the valve.
15. Valve installation requires consideration of which valve plate will be subjected to flow rate and pressure during liquid transfer.