Flat gate valve applicable to natural gas, oil, chemical, environmental protection and urban pipeline, gas pipelines, etc, conveying pipeline, vent system and steam storage device, used for on-off equipment. Z43 type with flow guide hole single disc type flat valve used in natural gas purification in the mining and long distance pipeline. Flat valve diameter scope: DN25 ~ 1200 pressure range: 0.6 MPa ~ 45 MPa 150 Lb ~ 3000 Lb have diversion hole flat valve used to need the ball of pipeline pigging, no diversion hole for don't need the ball on the pipeline pigging.