| 摘要 |
<p>A ball cock has a sealing internal lining to the casing where it is in contact both with the ball and with the shaft this lining comprises a coating of plastics, esp. of the fluorinated hydrocarbons group, such as PTFE, fluoropropylene etc. The surface of the casing which seats the gland may also have a coating of the same or similar material. Where the casing has flanges at both sides, this coating may also be continued over these flange faces. The valve is esp. suitable for liqs. contg. substances which can polymerise, crystallise or otherwise ppte in solid form and cause jamming. By using a lining of the type described, dead spaces where such pptn. can occur are eliminated.</p> |
