| 摘要 |
<p>The use of a second filter circuit ensures that no pressure differential is established. The tanker for use on a towed trailer includes a first circuit for establishing contact between the space inside the tanker and the ambient air. This circuit includes a dust and bacteria prevention filter. A second such circuit is also provided. If the first filter becomes blocked, a pressure reduction can occur within the tank and a detector senses this event. In such circumstances the second circuit is opened, enabling the passage of air to relieve the pressure difference. In addition to opening the second circuit, the detector is also able to initiate an alarm signal indicating that this has occurred. This draws attention to the blockage of the first filter. A manual control may also be provided enabling operation of the second filter circuit.</p> |
