D643HThe pneumatic flange hard seal butterfly valve pn6 ~ PN25 has low fluid resistance. When the medium and large diameter pneumatic flange butterfly valve is fully open, the effective flow area is large, and the opening and closing is quick and labor-saving. The disc plate can be opened and closed by 90 angle rotation. Because the medium force on both sides of the rotating shaft is nearly equal, the torque direction is opposite, so the opening and closing torque is small, and good sealing can be achieved under low pressure. Pneumatic flange butterfly valve is widely used in metallurgy, electric power, petroleum, chemical industry, air, gas, combustible gas and water supply and drainage pipeline.

D643HMain performance indexes of pneumatic flange hard seal butterfly valve pn6 ～ PN25

Return difference	Less than 2% of full belt travel
Basic error	With positioner: less than full stroke±2%
Amount of leakagel/h	Comply with ANSI b16.104 class IV standard
Adjustable rangeR	50：1

Design standard: GB / t12238-1989;
Flange connection size: GB / t9113.1-2000; GB / t9113.2-2000; GB / t9115.1-2000; GB / t9115.2-2000;
Structural length: GB / t12221-1989;
Pressure test: GB / t13927-1992; JB / t9092-1999;

1. Before installation, check whether the specification, pressure, temperature and corrosion resistance of butterfly valve meet the use requirements. Check whether the parts are damaged or loose.
2. The butterfly valve can be installed on the pipeline at any angle and should be closed; when welding the pipe flange, the valve sealing port should be blocked with a plate to prevent particles and sundries from damaging the sealing surface. After welding, take down the valve, clean the valve sealing surface and pipe cavity, and then install the fixed valve.
3. Please pay attention to the pressure bearing direction when the valve is closed.
4. Before installation, the sealing surface (sealing surface at both ends, sealing surface of butterfly plate and sealing surface of valve seat) shall be thoroughly cleaned to remove dust and dirt.
5. Before installation, the butterfly valve should be air tested, and the opening and closing position should be flexible, and the opening and closing position should be consistent with the position indicated by the pointer.
6. Manual operation, clockwise is off, counter clockwise is on, pointer indication is in place, it is not allowed to open and close the valve with additional force.
7. During the pressure test of the valve, it is not allowed to use single flange for installation and pressure test, but double flange installation and pressure test must be adopted. The test pressure shall comply with GB / T13927-92.
8. The bolts shall be tightened symmetrically and alternately instead of separately.
9. The limit screw has been adjusted before delivery, so it is not allowed to adjust it easily. Please refer to the manual for electric drive device.
10. When the electric butterfly valve leaves the factory, the opening and closing stroke of the control mechanism has been adjusted. In order to prevent the wrong direction when the power supply is connected, the user should first manually open it to the half open position before connecting the power for the first time, and then press the inching switch to check that the direction of the indicator wheel is consistent with the opening direction of the valve.
11. If the valve is found to be open and closed abnormally, the cause shall be found out for repair and elimination, so as to prevent the valve from being damaged due to opening and closing by means of applying force.