Valve device capable of fast switching and fine adjustment of flow

A valve device capable of fast switching and fine adjustment of flow, comprising:

• a valve seat unit, having a chamber therein, an outer surface of the valve seat unit being formed with an input hole, an output hole, a first axial hole and a second axial hole to communicate with the chamber, wherein the first axial hole and the second axial hole are disposed at two opposing sides of the valve seat unit, and the second axial hole and the first axial hole have central axes which are disposed concentrically;
• a switch unit, having a switch member disposed in the chamber, one end of the switch member being provided with a rotary shaft, the rotary shaft being inserted through the first axial hole for driving the switch member to turn relative to the valve seat unit with the center axis of the first axial hole as its axis, another end of the switch member being formed with a through hole corresponding to the second axial hole, a circumferential side of the switch member being formed with a first opening corresponding to the input hole and a second opening corresponding to the output hole, the first opening, the second opening and the through hole being communicated with one another;
• a fine adjustment unit, disposed in the second axial hole and movable along the central axis of the second axial hole to selectively penetrate the through hole and block the first opening and the second opening;
• wherein the valve seat unit has a seat, the seat has an upper surface, an opposing lower surface, and a circumferential side surface connected between the upper surface and the lower surface, the upper surface of the seat is recessed with the chamber, the seat is provided with a first cover outside the chamber, the first cover has the first axial hole, the lower surface of the seat has the second axial hole, and the circumferential side surface of the seat is formed with the input hole and the output hole opposite to the input hole;
• a leak-proof bushing, the leak-proof bushing being disposed between an inner wall of the chamber and an outer surface of the switch member, the leak-proof bushing having openings respectively corresponding to the first axial hole, the second axial hole, the input hole, and the output hole;
• and
• wherein an opening of the chamber is further enlarged with a pressing groove, the first cover has a pressing block corresponding to the pressing groove, the pressing block is engaged with the pressing groove, an outer peripheral side of the leak-proof bushing is provided with a pressing portion corresponding to the pressing groove, and the pressing portion is located between the pressing groove and the pressing block.