The dome valve 's spool is a spherical dome .During its opening and closing,there is a clearance of about 2mm maintained betwwen its pool and rubber gasket ring so that the both can move in a non-contact way for purpose of no friction between the both and reduction of abrasion.

Dome valve Main technical parameters:
Nominal pressure:1.0Mpa 
Medium temperature: Less than 200 degree C
Strength test :1.5Mpa
Seat test:1.1Mpa

Dome valve applicable medium:Uniform fine grain sustances like pulverized fuel ash.The rubber of gasket 's inflation pressure shall be guaranteed to be within 0.30-0.60Mpa and higher than the delivery pressure 0.15Mpa , and the working gas pressure shall be within 0.45-0.65Mpa while it is nessary to use clean , dry and uncompressed air.