Abstract: A method for testing vapor recovery units having phase II capabilities for integrity, blockage, or both is disclosed. The vapor recovery unit is modified for vacuum testing. To test the integrity of the unit, a vacuum is drawn in the unit to a predetermined level whereupon it is monitored for decay over a predetermined period of time to ascertain whether the unit is leaking. To test for blockage, a vacuum is continuously drawn in the unit while the lines associated with the phase II capabilities are disconnected from the dispensing station at the point most proximal to the station. Flow of fluid induced by the vacuum is then measured and compared to the desired rate of flow to ascertain the extent of blockage, if any.

Abstract: An apparatus and method for employing the apparatus in testing underground fluid containing lines for leaks. The apparatus comprises (a) a differential pressure transducer mounted to a reservoir for indicating volumetric change in the reservoir; (b) a temperature transducer mounted in the reservoir for monitoring temperature fluctuation in the reservoir; (c) a gauge pressure transducer mounted in the reservoir; (d) a remote temperature sensor and a data acquisition and processing system. The method for employing the apparatus comprises of connecting the apparatus to the line under test and entering certain parameters of a line under test and product temperature into the test computer. The test system then monitors volumetric change in the reservoir as well as pressure and temperature fluctuations in the line under test at 30 second intervals. At the end of the predetermined test period, the system calculates the leak rate during each five minute interval of the test as well as a cumulative leak rate.

Abstract: A seismic detector assembly is disclosed that includes a housing and a seismic detector or geophone located in the housing. The geophone has a pair of external terminals that are positioned asymmetrical to the longitudinal axis of the geophone. A printed circuit board having conductive strips for connecting the terminals to leader cables is located in the housing above the geophone. The printed circuit board has a pair of asymmetrical openings through which the asymmetrical terminals can extend only when the printed circuit board is oriented in one position relative to the geophone. Marks on the printed circuit board indicate which conductive strip should be connected to which terminal and the proper orientation of the printed circuit board relative to the truck that receives the output of the geophone.

Abstract: A regularly repetitive, almost periodic but non-regularly shaped waveform is amplitude sampled at an interval different from that of the waveform under investigation. For a voltage measurement, the positive samples are averaged for a predetermined count number (one set) and the negative samples are likewise averaged. Zero value samples are ignored. The highest absolute value of the two is taken as a meaningful measurement. Alternatively, one of these values can be selected. For a current measurement, a running average for a predetermined number of sets can also be developed. Finally, frequency can be developed by sensing the transitions and operating a counter on/off at the beginning and ending of a waveform cycle. The count of regular interval counts is then multiplied by the interval time to give the period of the waveform. The reciprocal of the period is a measure of the frequency.