Wellhead device is a device installed at the wellhead, which is used to control the pressure and direction of gas and liquid fluid, hang casing and tubing, and seal the annular space of tubing, casing and each layer of casing.
Wellhead equipment consists of casing head, casing suspension, casing head spool, tubing head, tubing suspension, etc.
Christmas tree is a wellhead device composed of gate valve, throttle valve and three (four) way. It is used for oil and gas testing after well completion, wellhead control of flowing well and mechanized production well, control the pressure of production wellhead and regulate the flow of oil (gas) wellhead
According to the output of the wellhead, it can be designed as a single wing or double wing structure.
Main control valve（Gate valve）In the design state of fully open or fully closed, it can be divided into expansion gate valve and flat gate valve (open / concealed)
Expansion valve: in the process of opening and closing, the thickness of the valve plate is the smallest, reducing the wear of the sealing surface of the valve plate and the valve seat, reducing the torque of opening and closing. The valve plate expands when it is fully open or fully closed, and the sealing is safe and reliable.
Flat Gate valve (concealed / open stem), no rising stem structure (concealed stem), open stem structure, with balance tail rod, floating between valve seat and valve plate - favorable for sealing between valve seat and valve plate sealing surface, floating between valve stem and valve plate - favorable for operating torque, upper sealing design - pressure replacement, bearing design - reducing operating torque.