| 摘要 |
<p>PURPOSE:To enable to change the range of setting flow rate with ease, by providing by-pass passages having variable by-pass ports independent of a main valve port designed to be variable in a conventional manner. CONSTITUTION:In case of controlling a flow rate by use of the value of constant flow rate determined by a main valve port 4, all of by-pass passages 13 are closed by use of a blind control plate 17 formed with no holes. In this state, by- pass valve ports 12 are all rendered inoperative, so that constant-flow control is made by the main valve port 4. On the other hand, in case of increasing the range of constant-flow rate, the flow rate can be changed with ease by replacing the control plate 17 by one having one or more holes capable of communicating such a number of by-pass passages 13 as to correspond to the increment of flow rate.</p> |
