| 摘要 |
The invention provides a hot and cold water mixing and flow control faucet of the hydraulically unbalanced piston type. A control stem of the piston passes through a seal of a self-energizing nature for connection to an actuating member operative to rotate and reciprocate the piston. The piston is substantially pressure balanced in the closed position by virtue that shut-off of the faucet is effected at the inlet ports, and is biased axially in the open position by virtue that the opposed pressure-effective areas of the piston are unequal. These opposed areas of the piston differ by an amount corresponding to the cross sectional area of the control stem, and the diameter of the stem is limited to a maximum of 6 mms. to correspondingly limit the force biasing the piston axially. Thus, the combined frictional drag required to prevent the piston shifting axially under the influence of line pressure can be of an order which is compatible with operation of the faucet by a conventional push-pull and rotatable knob, that is an actuating member having no mechanical advantage, as well as by an actuating member which provides a mechanical advantage, e.g. a lever. The arrangement also facilitates the placing of an outlet port or ports in the valve chamber in a variety of alternative positions, which assists in simplifying the construction of a range of faucets according to the invention, e.g. bath faucets, kitchen faucets, and the like.
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