Hitachi High-tech Corporation

Nobuhiro Tsukada

Kenichiro Nishiki

Yusuke Yota

Yuichiro Hashimoto

Sho Iwasa

Shinya Ito

Kazuhiro Noda

Yoshihiro Nagaoka

Jun Maeda

Kenta Imai

Eiichiro Takada

Daisuke Akieda

Ayano Otsubo

Hisao Inami

Tatsuki Takakura

Mitsuhiko Ueda

Mariko Miyazaki

Shoji Tomida

Midori Tobita

Yuka Miyake

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.

A flowpath switch valve is configured for extended service life by spreading the region, of the sliding surfaces of a stator and a rotor, that is subject to wear over the entirety of the sliding surfaces. The stator has fixed stator flowpaths, and the rotor has rotor flowpaths. A flowpath switch valve, depending on the rotor rotation state, realizes connection patterns that include: a first connection pattern wherein a rotor flowpathconnects a fixed stator flowpathand a fixed stator flowpath; a second connection pattern wherein the rotor flowpathconnects the fixed stator flowpathand a fixed stator flowpath; a third connection pattern wherein a rotor flowpathconnects the fixed stator flowpathand the fixed stator flowpath; and a fourth connection pattern wherein the rotor flowpathconnects the fixed stator flowpathand the fixed stator flowpath

Flow passage switching valve, flow passage switching valve system, and liquid chromatograph

A liquid chromatographic apparatus which removes air bubbles during preparatory operation for apparatus startup includes a liquid feeding pump to feed a solvent, an injector to inject a sample into the solvent, a separation column to receive the solvent and the sample through the injector and separate the sample into components, a detector to detect the components supplied from the separation column, a pressure sensor to measure a pressure in a solvent flow channel of the liquid feeding pump, and a controller to control a purge operation for removing air bubbles in the solvent flow channel by the liquid feeding pump, determine whether a pressure change amount in the solvent flow channel measured by the pressure sensor during the purge operation is a specified change amount or larger, and complete the air bubble removal operation when the pressure change amount is the specified change amount or larger.

Liquid chromatographic apparatus and air bubble removal method of liquid chromatographic apparatus

An automatic analysis device including a container filled with a fluid, a pressure source, a probe which separates the fluid within the container, the probe associated with a probe position, a motor which moves the probe, a flow path which connects the probe and the pressure source, the flow path associated with a flow path position, a pressure sensor which measures pressure variations within the flow path corresponding with time series management data, and a sensor which detects a liquid level position within the container. A condition of flow generated within the flow path is estimated based on (i) the time series measurement data and (ii) a reference value of pressure according to fluid pressure based on gravitational acceleration in a position of the pressure sensor calculated based on (a) the probe position or the flow path position and (b) an immersion depth of the probe determined by the sensor.

Automatic analysis device

A liquid chromatograph has a long-life flow passage switching valve with reduced abrasion caused by sliding of flow passage end portions of a stator and flow passage end portions of a rotor seal. The flow passage switching valve includes: a stator; and a rotor seal connected with a rotor configured to rotate and slide on a circumference with respect to the stator. The stator has stator flow passages that open to the rotor seal. The rotor seal has a rotor seal flow passage for coupling two or more of the stator flow passages. A flow passage end portion that is positioned at a tip end in a sliding direction of the rotor seal flow passage is positioned in a direction opposite to the sliding direction of the stator flow passage end portion to be connected to the rotor seal flow passage, at least at the start of sliding.

Flow passage switching valve and liquid chromatograph having the same

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.

Liquid feeding apparatus and liquid feeding method

A liquid feed pump which increases the liquid flow velocity in a stagnation area in the pressure chamber of a plunger pump, thereby improving the liquid replacement speed in the plunger pump. When the liquid in the liquid feed pump is replaced, a first plunger slides back and forth in the space between a lower limit point and an upper limit point, and the second plunger stops at least temporarily at a position near to the upper limit point or slides back and forth for a shorter distance than when the liquid feed pump usually feeds the liquid.

Growing community of inventors

Tokyo, Japan

Nobuhiro Tsukada