Abstract: Flat gate valve is critical equipment in the well control device.Due to the unreasonable design structure,residual mud is usually heavy in the currently used flat gate valve.If the flat gate valve is not used or it is spared for a period of time,mud will be deposited in the cage.As a result,the valves cannot be shut down orin the process of use,overexert will wrench or even break the valve rod.To solve these problems,a new type anti-settling sand flat gate valve was designed based on Z23Y-700 series gate valve.The new anti-grit flat gate valve adopts double seat design and cleaning hole design,which makes the valve seat easy to be installed and valve cleaning more convenient.To prevent the slurry into the valve chamber,we also add a new gate and fender to the gate valve.Finally,in order todetect the sealing performance ofthe plate gate valve,the pressure test and the hydrostatic test were carried out at 70 MPa.And the valve body cover was subjected to ultrasonic testing and material chemical analysis.The result shows that the designed flat gate valve is reasonable and meets the actual working conditions.

Key words: flat gate valve, the grit, the valve body, seal