Y-type cylinder-controlled valve assembly

A Y-type cylinder-controlled valve assembly comprising:

• a valve body having a through passage for fluid flow, a sleeve inclinedly extending outward from said passage, and an opening formed at an end of said inclined sleeve for communicating said sleeve with said passage;
• a cylinder connected to said inclined sleeve by means of a coupling sleeve and consisting of an inner piston, a main shaft extending from a bottom side of said piston toward and above said opening in said valve body, a lower cylinder seat having a port for sending high-pressure gas into said cylinder to actuate said piston, and a spring bearing against said piston to provide recovery force for said piston to return to an original position thereof;
• and
• a valve provided at a free end of said main shaft such that said valve is moved by said piston to open or close said opening is said valve body;
• wherein
• said cylinder has a reduced upper portion of which the inner diameter is smaller than the outer diameter of said piston, and a lower portion in which said piston reciprocates;
• said reduced upper portion of said cylinder serving as a means to stop said piston and thereby defining a maximum travel of said piston to minimize the force directly applied to said valve when said value is completely moved away from said opening toward said cylinder;
• and wherein
• said cylinder is coupled at an inside end thereof distal said valve to an indicator, said indicator extending out of a top end of said cylinder and being covered by a transparent hollow dust cap which seals said top of said cylinder.