| 摘要 |
<p>Servo-operated, piston type, slide valve for closing liquid additive into a continuous flow of water to be treated. The valve block has a side entry for additive to pass into a valve cylinder from which it is drawn into teh flow of water to be treated via the open end of the cylinder, e.g. leading into an ejector pump. The additive side entry can be isolated from the valve outlet by advancing a piston which, nevertheless, does not form a complete seal with the cylinder wall; at all times; there is tiny flow of sealing water to the back face of the piston at a pressure highe rthan that of the additive. The additive entry is pref. fitted with a no(-return valve.</p> |
