초록 ▼

An automated liquid volume monitoring system and method for determining storage tank leak rate. Volume changes necessary to maintain storage tank liquid level, and volume changes due to temperature changes, are substantially constantly measured and calculations are made to determine actual leak rate

An automated liquid volume monitoring system and method for determining storage tank leak rate. Volume changes necessary to maintain storage tank liquid level, and volume changes due to temperature changes, are substantially constantly measured and calculations are made to determine actual leak rate. Leak rate calculations are made frequently and averaged periodically to provide updated leak rate indications for a system operator.

대표청구항 ▼

An automated liquid volume change monitoring system for a storage tank, said system comprising: level sensor means positioned to detect small changes in liquid level; means for providing a signal from said level sensor means indicative of rise or fall of liquid level; means for computing the volume

An automated liquid volume change monitoring system for a storage tank, said system comprising: level sensor means positioned to detect small changes in liquid level; means for providing a signal from said level sensor means indicative of rise or fall of liquid level; means for computing the volume of liquid change in said tank represented by the signal from said liquid level signal providing means; means for providing a signal representative of liquid volume change due to detected level changes; temperature sensing means comprising: electrically variable resistance means located within said tank at a position representative of temperature of the liquid therein, the resistance of said resistance means changing substantially proportionally to the temperature change of the liquid within said tank; a bridge circuit having said variable resistance means as one of its legs; and means for providing an output signal from said bridge circuit representative of change in temperature detected by said variable resistance means; means responsive to said signal from said bridge circuit to calculate tank liquid volume change due to temperature change; means to provide a signal representing thermal liquid volume change; computation means responsive to said signal representing liquid volume change due to thermal changes and to said signal representing liquid volume change due to detected level changes to provide a signal representing storage tank leak rate; means for providing indication of the leak rate; liquid flow pipe means extending from an external location into the liquid in said tank; level adjusting means connected in said flow pipe means; auxiliary tank means connected to said flow pipe means precision weighing means coupled with said auxiliary tank means to accurately determine liquid weight differences within said auxiliary tank means; means to provide a signal to said volume computing means from said weighing means representing the volume of liquid in said auxiliary tank means; means responsive to said rise and fall indication signal to provide a level adjustment signal; and means connecting said level adjustment signal to said level adjusting means to energize said level adjusting means to transport said liquid between said storage tank and said auxiliary tank to maintain the liquid level in said storage tank substantially constant; said volume computing means being responsive to said weighing means signal to calculate the amount of liquid transported between said storage tank and said auxiliary tank and provide a signal representing liquid volume change; said flow pipe means comprises an inlet pipe and an outlet pipe; said level adjusting means comprises a pump connected in said outlet pipe to transport liquid from said storage tank to said auxiliary tank; said level adjusting means further comprising valve means connected in said inlet pipe to allow liquid to flow from said auxiliary tank to said storage tank under the force of gravity; said level adjustment signal controlling the operation of said pump means and said valve means to maintain substantially constant liquid level in said storage tank.