When testing a well, surface shut off is ususally provided by a flow control head or flowhead hat functions as a temporary Christmas tree. The flowhead is located on top of the well and is the first piece of equipment at the surface that fluid flows through.

The flowhead consists of four gate valves: A mster valve, two wing Valves and a swab valve. The outlet wing valve is opened and closed Using an hydraulic actuator. Above the swab valve is a lifting Subassembly with a threaded connection. The threaded connection Is often called a quick union.

The quick union is used to connect Auxiliary pressure equipment which is needed if tools are to be Run downhole. Some flowhead have a protection frme bolted to The main block to prevent damage to the valves during handling.