Driving method of pump

Abstract

A mixing pump (1) performs a correction process for displacing a displacement member (17) in the direction of decreasing the internal volume of a pump chamber (2) when transition is made from a suction process to a delivery process, and performs a correction process for displacing the displacement member (17) in the direction of increasing the internal volume of the pump chamber (2) when transition is made from a delivery process to a suction process. During a correction process, the internal volume of the pump chamber (2) under an enclosed state is increased or decreased by closing the suction ports (30a, 30b) and the delivery ports (40a, 40b) of the pump chamber (2) thereby displacing the displacement member (17). Instability due to backlash of the drive system of the displacement member (17) can be eliminated, and pressure difference between the inside of the pump chamber (2) and the fluid suction side or delivery side can be eliminated. Consequently, variation in fluid suction quantity or delivery quantity can be eliminated or suppressed when transition is made between a suction process and a delivery process.

Description

technical field [0001] The present invention relates to a driving method of a pump device, which sucks fluid from a suction port and discharges the sucked fluid from a discharge port by displacing a displacement member such as a diaphragm forming a part of a pump chamber, such as a diaphragm pump. Background technique [0002] As a mixing pump device that mixes a plurality of fluids in a predetermined ratio and discharges them, there is known one that sucks a plurality of fluids into a single pump chamber, mixes them in the pump chamber to form a mixed fluid, and discharges the mixed fluid from the pump chamber. fluid. Patent Document 1 discloses a mixing pump device that sucks and mixes a plurality of solvents by a plunger pump in a high-speed liquid chromatography analyzer, and discharges the resulting mixed fluid to a column. [0003] In the mixing pump device disclosed here, the rotation of the stepping motor is transmitted to the plunger through the cam mechanism to in...

AI Technical Summary

Problems solved by technology

[0006] In addition, in the case of a diaphragm pump, when the diaphragm begins to deform, there is a dead zone in which the volume of the pump chamber does not change even though it deforms.

Therefore, in the mixing pump device using the diaphragm pump, when switching from the discharge process to the suction process, or from the suction process to the discharge process, the change in the internal volume of the pump chamber lags behind, and the amount of fluid sucked into the pump chamber, or Error in fluid discharge from pump chamber

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