| 摘要 |
<p>A vapor recovery system monitoring system includes a vacuum monitor and a vent sensor. The vacuum monitor has a signal relay in communication with a vacuum system served by a vacuum source to generate a first signal upon actuation of the vacuum source for recovery of displaced fuel vapor and a second signal when a minimum vacuum level is achieved; a timer measuring elapsed time between first and second signal; a comparator comparing elapsed time with a predetermined standard; and an error display actuated when the predetermined number of instances of elapsed time is exceeded. The vent sensor, mounted to a vent conduit for an underground storage tank, defines an orifice creating a pressure differential when volume flow of vent emission exceeds a predetermined level; a pressure differential switch; a counter receiving a signal from the pressure differential switch for indication of venting frequency over a predetermined time period; a timer receiving a signal from the pressure differential switch for indication of total venting time over a predetermined time period; a comparator comparing total venting time with a predetermined acceptable total venting time; and an error message display actuated when a predetermined acceptable total venting time is exceeded. A method for monitoring a vapor recovery system is also described.</p> |
