An improved hydrant structure with an integral piston set is provided with the hydrant main body having a valve chamber for receiving a water control valve. The water control valve is composed of a valve member, rubber pads, a piston cylinder with an integrally enclosed structure and a piston rod disposed inside the valve member, a valve rod, a cover, a valve cap, and a rotary button; the outer side of the piston cylinder is formed with different outer diameters, and the preset portions thereof are formed with a water inlet and a water outlet holes, such that the piston rod can be adjusted to alter the relative relation, thereby achieving functions of starting/terminating water supply and adjusting water mixing ratio. The piston cylinder with an integrally enclosed structure is formed through a stainless steel base pipe and a plastic sleeve member enclosing the exterior thereof.

A self-draining hydrant comprising a supply line coupled to an outlet and a housing adapted for placement in the ground and for coupling to a water supply. The housing can selectively provide water from the water supply to the supply line and has a reservoir for receiving drained water from the supply line. A piston is movable in a direction of travel from a first position to a second position within the housing for engaging the drained water and expelling it from the reservoir. The piston has a seal for engaging the housing to provide a seal with respect to the drained water. The housing has at least one slot extending in the direction of travel and engageable by the seal for permitting drained water to pass the seal.

A structural improvement of piston set for use in hydrant is provided; a hydrant main body having a valve chamber for receiving a water control valve is mainly provided, the water control valve is composed of a valve member, rubber pads, a piston cylinder and a piston rod disposed inside the valve member, a valve rod, a cover, a valve cap, and a rotary button; the outer side of the piston cylinder is formed with different outer diameters, and preset portions thereof are formed with a water inlet and a water outlet holes, thus the piston rod can be adjusted to alter the relative relation, thereby achieving functions of starting/terminating water supply and adjusting water mixing ratio; and characterized in that: the piston cylinder is formed through a stainless steel base pipe and a plastic sleeve member enclosing the exterior thereof; accordingly, better industrial application valves are provided.

A self-draining hydrant comprising a supply line coupled to an outlet and a housing adapted for placement in the ground and for coupling to a water supply. The housing can selectively provide water from the water supply to the supply line and has a reservoir for receiving drained water from the supply line. A piston is movable in a direction of travel from a first position to a second position within the housing for engaging the drained water and expelling it from the reservoir. The piston has a seal for engaging the housing to provide a seal with respect to the drained water. The housing has at least one slot extending in the direction of travel and engageable by the seal for permitting drained water to pass the seal.