RT series subsurface safety valve is a kind of tubing retrievable safety valve which
is controlled on the surface through hydraulic control line. It directly connects to the
tubing string as part of production workstring. After installation, it is operated by the
pressure in control line. While certain amount of hydraulic pressure is applied
through the control line to the safety valve, the valve will be open; while the
pressure is released, the safety valve will be closed and the tubing string is closed
at the same time.