| 摘要 |
The invention is a needle valve comprising at least one hollow needle and a seat. The hollow needle is comprised of a smooth surfaced hollow shaft and a port adapted to allow fluid communication between the interior and the exterior of said needle located in the side of the shaft at the distal end close to the tip of said needle. The seat comprises at least one bore adapted to accommodate one of the at least one needles through it. The needle and the bore can move one relatively to the other and the bore is provided in, or is fitted with, resilient material such that the outer diameter of the needle is greater than the inner diameter of at least part of the bore. As a result the passage of the shaft of the needle in the bore creates a closely -matched shaft and sheath, which blocks the passage of fluid through the port. |
