Wellhead Valve Operating Precautions
The valves must be operated carefully when opening or closing. Some valve types have a shear pin between the handle and stem, which will shear to protect the valve’s internal components, if excessive force is applied. The master valve should not be used to close in a flowing well, except in an emergency. The swab or wing valves are typically used. Each time the gates of the valve shut in a flowing well, the increase in velocity of the well fluids during the closing action can cause wear across the seal faces. It is easier and safer to replace the seats and gates in valves, other than the master valve in the tree. Always count the number of valve turns made when closing. This is a prudent check against jamming the toolstring or wire in the tree, in the event that the tools have been raised fully into the lubricator. source: aqemachinery.com Tubing Hanger The tubing hanger is the device that supports the production tubing within the tubing head. A seal assembly on the body of the tubing