Structural improvement of piston set for use in hydrant

A structural improvement of piston set for use in hydrant, the hydrant mainly including a hydrant main body, two side of the hydrant main body being respectively formed with a water inlet pipe end for being connected to a water supplying pipeline, the front end thereof being extended with a water outlet pipe end for being connected to a water dispensing pipeline, preset locations defined at the two water inlet pipe ends being respectively disposed with a water control bolt for adjusting the water inlet amount, the center of the hydrant main body being upwardly extended with a valve chamber for receiving a water control valve, the water control valve being composed of a valve member, rubber pads at two sides of the valve member, a piston set disposed inside the valve member, a valve rod for operating the piston set, a cover, a valve cap, and a rotary button for locking and operating the valve rod, wherein the piston set being composed of a piston rod and a piston cylinder, the outer side of the piston cylinder being designed to be formed with different outer diameters, and preset portions thereof being formed with a water inlet and a water outlet holes, so that the valve rod being able to be operated for regulating and controlling the piston rod disposed in the interior so as to alter the relative relation, thereby achieving functions of starting/terminating water supply and adjusting the water mixing ratio;

• and characterized in that:
• the piston cylinder being formed through a stainless steel base pipe and a plastic sleeve member covering the exterior thereof, the stainless steel base pipe being formed through directly cutting a stainless steel pipe, and preset portions thereof being formed with a water inlet and a water outlet holes, after the stainless steel base pipe being disposed in a preset mold, the plastic sleeve member is formed through being injected into the mold having preset cavities, thereby enabling the plastic sleeve member to integrally enclose at the exterior of the stainless steel base pipe, and the plastic sleeve member being respectively formed with a hole slot corresponding to the water inlet and the water outlet holes of the stainless steel base pipe, thereby forming the piston cylinder having composite materials.