| 摘要 |
<p>A bleed valve comprises a valve body (10) and a bleed screw (12) that can be screwed into and out of the body, a primary valve (20,22) between the bleed screw and the body which is closed when the bleed screw is fully screwed into the body (10), and a secondary valve (30,34) between the bleed screw (12) and the body (10) which is closed when the bleed screw (12) is unscrewed to restrict the flow of liquid through the valve. <IMAGE></p> |
