| 摘要 |
<p>An apparatus for measuring the level of groundwater surrounding an access chamber of similar underground installation, comprises a pipe having a first open end, sealed fluid communication means between said open end and the environment outside the access chamber, a second, normally closed end disposed within the chamber above the level of the first end, and means for temporarily opening said second end to allow measurement of the ground water level in the pipe section intermediate said two ends. The first and second ends preferably both have sealed bulk head fittings, with the second end being additionally fitted with an on/off valve, preferably manually operated, located above the bulk head fitting, whereby the second end is normally closed and is only opened when the test is being conducted, returned to the closed position when the operator releases the lever operating the valve. The valve is normally closed in case of internal spillage within the chamber which might rise to a level such that it might enter the second end of the pipe and hence drain into the pipe, escaping into the surrounding ground and giving rise to a contamination problem.</p> |
