| 摘要 |
PURPOSE:To dispense with attached equipment such as a riser by measuring a negative pressure acting on a pipe connecting a pump and an underground tank. CONSTITUTION:While a pump 5 is not driven, a hydrostatic head negative pressure Ph acts on a negative pressure detector 6 due to a head (h) from the negative pressure detector 6 to the tank oil surface. The negative pressure Ph is converted into an electrical signal and then, into a digital signal with an interface 13 to be inputted into a CPU12. The difference H-h between the height H from the bottom of a tank 2 to the negative pressure detector 6 and the head (h) is inversely proportional to the depth of liquid in a tank 2, namely, the liquid surface level. Thus, the residual capacity of fuel is determined by the relationship between the hydrostatic head negative pressure Ph stored in a ROM14 and the residual capacity Q and is outputted to be shown on an indicator 15. In addition, the capacity is compared with the preset minimum liquid level and the maximum liquid level and when it is below the minimum liquid level, the replenishing of a fuel oil to the tank is promoted while when it is above the maximum liquid level, a command is given to stop the supply of oil to the tank. |
