Method of oil product receipt and metering

A method of measuring a liquid medium with low pressure of saturated vapors when pumped out of a tank (1), said method comprising at least one main stage and at least one subsequent stage, wherein each of the at least one main stage is followed by a one of the at least one subsequent stage;

• the main stage comprises using a first line pump (4) to pump out the liquid medium from the tank (1) and in a first instrument line (Fa, Ta, ρa) equipped with a mass meter with a first flow rate range, the subsequent stage is initiated by the first line pump (4) being stopped, whereby the method enters the subsequent stage, during the subsequent stage remnants of the liquid medium are collected from the tank (1) and inner cavities of the first instrument line (Fa, Ta, ρa) into a bottom of a system inner volume (9) by gravity;
• and from a bottom point of the bottom of the system inner volume (9), the liquid medium is supplied by a second pump (12) into a second instrument line (Fb, Tb, ρb) equipped with a mass meter, a mass measuring capacity of the second instrument line (Fb, Tb, ρb) is at least one order of magnitude less than that of the first instrument line (Fa, Ta, ρa), when the number of performed main stages and subsequent stages reaches a predefined value or another condition is met, a measurement result is calculated by summing all medium masses from all main stages and subsequent stages, the method further comprising giving a command to enter the subsequent stage and also to finish the next subsequent stage when currently active mass meter readings correspond to a level of bubbles in the liquid medium above a predefined value.

A method of measuring a liquid medium with low pressure of saturated vapors when pumped out of a tank (1), said method comprising at least one main stage and at least one subsequent stage, wherein each of the at least one main stage is followed by a one of the at least one subsequent stage;

• the main stage comprises using a first line pump (4) to pump out the liquid medium from the tank (1) and in a first instrument line (Fa, Ta, ρa) equipped with a mass meter with a first flow rate range, the subsequent stage is initiated by the first line pump (4) being stopped, whereby the method enters the subsequent stage, during the subsequent stage remnants of the liquid medium are collected from the tank (1) and inner cavities of the first instrument line (Fa, Ta, ρa) into a bottom of a system inner volume (9) by gravity;
• and from a bottom point of the bottom of the system inner volume (9), the liquid medium is supplied by a second pump (12) into a second instrument line (Fb, Tb, ρb) equipped with a mass meter, a mass measuring capacity of the second instrument line (Fb, Tb, ρb) is at least one order of magnitude less than that of the first instrument line (Fa, Ta, ρa), when the number of performed main stages and subsequent stages reaches a predefined value or another condition is met, a measurement result is calculated by summing all medium masses from all main stages and subsequent stages, the method further comprising at least on of the following:
• a) giving a command to enter the subsequent stage and also to finish the next subsequent stage if a diagnostic error occurs in any of the first or second instrument lines or b) determining a command to enter the subsequent stage by a requirement not to exceed a certain value of a current load on an excitation coil of a mass meter sensor of the first instrument line.