... -to-mental seal is used between bonnet and body, gate and seat, seat and body PFF Series Gate Valve PFF Series Gate Valve• Full bore design eliminates efficiently ... to-mental seal is used between bonnet and body, gate and seat, seat and body.• The surface of gate and seat is welding overlay ... H2S,CO2• Working Temperature: -46°C~121°C(Class LU)• Material Class: AA,BB,CC,DD,EE,FF,HH• Specification level ...