Hitachi High-tech Corporation

Yusuke Yota

Daisuke Akieda

Nobuhiro Tsukada

Sho Iwasa

Yuichiro Hashimoto

Jun Maeda

Provided is a technology for reducing the capacity of a liquid feeding pump and enabling liquid feeding with little pulsation. A liquid feeding pump according to the present disclosure is provided with: a first plunger pump having a first plunger; a second plunger pump having a second plunger and connected in series with the first plunger pump; a pressure sensor disposed downstream of the second plunger pump; and a control unit that accepts the input of a liquid discharge pressure measured by the pressure sensor and that controls the driving of the first plunger and the driving of the second plunger. The control unit calculates the rate of change in the pressure of the liquid on the basis of the past compression distances of the plunger for when the liquid was compressed by the first plunger pump and the pressure at the completion of compression, predicts the compression distance of the first plunger on the basis of the rate of change in pressure and the present discharge pressure, and determines the timing at which the compression performed by the first plunger will be completed on the basis of the predicted compression distance.

Liquid feeding pump and liquid feeding method

The present invention provides a technique that enables liquid feeding with small pulsation by reducing the volume of a liquid feeding pump. Disclosed is a liquid feeding pump comprising: a first plunger pump that has a first plunger; a second plunger pump that has a second plunger and is connected to the first plunger pump in series; a pressure sensor that is disposed on the downstream side of the second plunger pump; and a control unit that accepts an input of the discharge pressure of a liquid measured by the pressure sensor to control driving of the first plunger and driving of the second plunger, wherein when the first plunger pump compresses the liquid, the control unit drives the first plunger at a first speed, and then decreases the speed to a second speed slower than the first speed before the compression is completed, and wherein the control unit discharges the liquid from the second plunger pump by driving the second plunger in parallel with the driving of the first plunger.

The present invention relates to a liquid feeding apparatus capable of feeding a liquid with high accuracy. The liquid feeding apparatus includes a liquid feeder having a downstream side, a plunger, and a cylinder that is configured for aspirating and discharging a solvent when a plunger slides. The liquid feeding apparatus further includes a pressure sensor for the solvent to be discharged, a selector valve configured to switch between a plurality of solvents to be aspirated and discharged, and a controller configured to control the liquid feeder and the selector valve. The controller controls the selector valve in synchronization with an aspiration operation of the plunger so that a mixing ratio of the solvents changes, controls the plunger to cause the plunger to operate at first and second accelerations that are different from each other, and suppresses a fluctuation of the solvent to be aspirated by the plunger.

Growing community of inventors

Tokyo, Japan

Yusuke Yota