| 摘要 |
<p>PNEUMATICALLY PROPELLED DUCT MOTOR A duct motor for carrying drawing ropes and the like through cable ducts consists of two inflatable gripper bags and a telescopic section. The duct motor is driven by compressed air, and operates by one gripper bag inflating, telescopic section extending, the other gripper bag inflating and the one gripper bag deflating, telescopic section contracting and the cycle being repeated. Compressed air is distributed within the duct motor by means of a distribution valve and a pair of inflation and deflation values associated with each gripper bag. One distribution valve is not located between the gripper bags and this valve has a valve stem which is hollow, and is used for conveying compressed air from an input orifice to the remote end of the duct motor i.e. the other gripper bag.</p> |
