| 摘要 |
<p>The device to prevent leakages from a liquid tank, particularly a tank for heating oil, consists of a vacuum pump or other source of low pressure and an intermediate tank via which the oil tank pressure is reduced. The intermediate tank is included in the system of pipes taking and returning oil from the tank. There is a valve isolating the vacuum pump from the intermediate tank, the valve being operated by and responding to the pressure in the system. The vacuum pump is similarly controlled. The intermediate tank has high and low level switches operating and controlling the system. The pipework can enter the intermediate tank from above, and this tank can be above the level of the pump, and easily accessible.</p> |
