1.Material:
Body: Casting AL alloy
Breathing valve: AL alloy
Handle: steel
Safety locker: SS
Seal: NBR
2.Feature:
All types manhole cover has the breathing valve
Breathing valve's different pressure set can fit different operation requirement
Breathing valve has the automatically seal's function,can avoid leakage under emergency
Fit EN13317:2002 standard
3.Parameter:
| Size | 20" |
| Breathing valve | 10" |
| Pressure resistance | 0.254MPA |
| Open pressure | 21KPA-32KPA |
| Max air flow rate | 7000m³ /H |
| Connect way | Flange |
| Temperature | -20 to 70 ℃ |