| 摘要 |
<p>The water circulation device includes a valve which has four inner conduits each operatively linking the respective tubes to the dental handpiece. Furthermore, a bypass channel is formed in the valve, between the valve member water conduit and discharge conduit. A piston is movable in the bypass channel, between a first unobstructive position in which the water is free to flow from the water conduit into the discharge conduit, and a second obstructive position in which the piston blocks in a fluid-tight fashion the bypass channel, to prevent the water from flowing into the discharge conduit. A spring continuously forces the piston towards its first unobstructive position. Thus, in the handpiece inoperative condition, when no high-pressure air flow runs through the high-pressure air conduit, the water is free to flow in the valve from the water conduit into the discharge channel, thus not reaching the handpiece and continuously flowing to prevent the water from stagnating.</p> |
