Hitachi, Ltd.

Hitachi-High-Technologies Corporation

Hitachi Automotive Engineering Co., Ltd.

Kunihiko Takao

Kenji Hiraku

Isao Hayase

Hironori Kaji

Yukio Takahashi

Masahito Ito

Kenji Tojo

Kenichi Kawashima

Masaru Ito

Atsushi Suginuma

Hiroyuki Yamada

Kenichiro Tokuo

Yozo Nakamura

Masahiro Takebayashi

Tadahiko Nogami

Toshio Sudo

Takashi Yokoyama

Yuzo Kadomukai

Yoshihiro Nagaoka

Hirokatsu Kohsokabe

Atsuo Kishi

Kimihiko Ishii

Hideo Usui

Yasushi Muramoto

Yoshishige Endo

Shigeru Machida

Kisaburo Deguchi

Atsuji Saito

Hiroaki Hata

Yuji Yoshitomi

Masao Mizukami

Daisuke Akieda

Masaru Yamasaki

Kenichi Oshima

Kosaku Sayo

Kazuo Sekigami

Toshikazu Ito

Akira Tezuka

Takashi Degawa

Takeshi Kouno

Tsuneo Kan

Kenji Emi

Kiyosi Yamamoto

Masahiro Moritaka

Shigetaroo Tagawa

It is possible to correctly determine whether a change in the pressure or flow rate is caused by normal opening and closing operations of a check valve and to monitor in real time whether an operation of a check valve is normal or abnormal in a liquid supply device. Light is introduced in the check valve and a change in the quantity of light transmitted through or reflected by the check valve, caused by the opening and closing of the valve is detected, so that the opening and closing operations of the check valve can be directly detected. The check valve is arranged in a pipe in the liquid supply device, and a change in the pressure in the pipe is monitored on the basis of a signal from a pressure sensor and a signal which represents the opening and closing of the check valve.

Liquid supply device using check valve and reactive liquid chromatography system

This liquid feeding system has the first and second pumps each of which is provided with a plunger. Liquid sucked through each of the pump suction ports is discharged out of the discharging port through the first pump and/or second pump. Under the starting operation mode, the second pump is stopped and only the first pump is operated. When the discharging pressure at the discharging port reaches up to a predetermined value, the starting operation mode is changed over to the normal operation mode. Under the normal operation mode, the first pump is stopped and only the second pump is operated.

Liquid chromatograph device

Disclosed herein is a separation column comprising a porous block covered with a coating wherein space-free adhesion is attainable therebetween by low temperature process without releasing octadecylsilyl bases and others from the porous block. A monolith rodis covered with a metal or resin coating. Then, the monolith rodcovered by the coatingis further covered with a rod retainermade of a low melting point metal (melting point 100-200 degrees C.) to form a column body. Since the rod retaineris formed by pressure molding at low temperature (100-200 degrees C.). It is therefore possible to absorb the surface irregularities of the monolith rodby the coatingwhile octadecylsilyl bases and others from are released when the retaineris formed. This allows the potential separation ability of the porous block to be brought out maximally.

Separation column and liquid chromatography apparatus using the same

Provided is a liquid chromatograph pump system which sucks eluent from an eluent reserving container, and which feeds pressurized high pressure eluent into a column, wherein a plunger reciprocating in a cylinder is formed on its outer peripheral surface with a stepped part along the sliding direction of the plunger in the cylinder so as to define a working chamber between the stepper part and the inner wall surface of the cylinder, the flow rate of the liquid chromatograph pump being determined by the volume of the working chamber and the traveling speed of the plunger, thereby it is possible to stably feed a liquid at an extremely low flow rate, and to satisfactorily expel air bubbles upon a start of the liquid chromatograph pump system.

Pump for liquid chromatograph

Liquid feeding system

The invention provides a pump for liquid chromatography excellent in feeding liquid stably at an extremely low flow rate and in discharging bubbles at startup. In a pump for liquid chromatography including a cylinder and a plunger that reciprocates in the cylinder to suck and discharge fluid, the pump further includes a large-flow-rate pump that feeds liquid by the plunger, a small-flow-rate pump that feeds the liquid by the plunger, motion conversion means that converts the rotational motion of a motor to a reciprocating motion, an actuator that directly drives the plunger, and a drive part that drives the actuator, and selectively switches means for driving the plunger.

Pump, pump for liquid chromatography, and liquid chromatography apparatus

In a pump for feeding a liquid for chromatography, first and second plungers form first and second volumes respectively together with first and second chambers, the first plunger is prevented from changing the first volume sufficiently for feeding the liquid between the first and second volumes when the second plunger decreases the second volume to discharge the fluid from the second volume to an outlet path of the pump for the chromatography.

Liquid chromatograph pump with dual cylinders and dual plungers

The invention provides a pump for liquid chromatography excellent in feeding liquid stably at an extremely low flow rate with high accuracy and in discharging bubbles at startup. At startup, a first plunger feeds solvent at a large flow rate to discharge bubbles in a pump and to fill the solvent into the pump in a short time and in a normal operation, the first plunger is stopped and the second plunger is pushed into a second pressure chamber at a low speed to feed the solvent at a low flow rate. When the second plunger reaches full stroke, the second plunger is pulled back at a high speed and at the same time the first plunger is pushed into a first pressure chamber in synchronization with the pullback of the second plunger to control the flow rate passing a discharge passage to a constant value at all times by a controller. Further, while the second plunger feeds the solvent, the first plunger is slightly pushed into the first pressure chamber to keep pressure in the first pressure chamber at pressure equal to or less than pressure in the second pressure chamber.

Pump for liquid chromatography

Liquid chromatograph pump and control method therefor

The unevenness of injection rates of cylinders is reduced in a fuel supply system of a direct injection engine which uses a variable-displacement single plunger pump. The unevenness of injection rates of cylinders can be reduced by effecting a control such that the cam , which drives the high-pressure fuel pump , makes one reciprocation, while the engine makes explosions in two cylinders, and by causing the controller to extend the injection time width of one of two injectors which inject during one discharge of the high-pressure fuel pump and to shorten the injection time width of the other injector.

Fuel supply system

In a fuel supply apparatus disclosed, a variable displacement mechanism is driven once every two or more reciprocating motions of the plunger of a high-pressure fuel pump to control the delivery flow rate, so that the delivery flow rate control can be performed without having to raise the responsiveness of the variable displacement mechanism even when the reciprocating cycle of the plunger is short.

Fuel supply apparatus and method of control thereof

In order to provide a method for high volume and high pressure operation of a variable delivery type single cylinder plunger pump, the displacement of the piezoelectric element is magnified by a hydraulic displacement magnifying mechanism comprising a large-diameter bellows a small diameter bellows and working fluid and an engaging member is displaced to control the time interval of opening and closing the intake valve The large-diameter bellows is used at all times in the state compressed in the direction of displacement transfer, thereby ensuring that the pressure of the working fluid is maintained at a positive value to prevent vapor from being generated. The thermal expansion of a casing is selected in such a way that the total thermal expansion of the piezoelectric element and hydraulic displacement magnifying mechanism in the direction of displacement transfer is approximately the same as the thermal expansion of the casing whereby highly efficient driving is provided.

High pressure fuel pump

A fuel supply system for a direct injection engine which has a variable capacity single cylinder plunger pump and two fuel rails. Offices are disposed at the upstream side inlets of both fuel rails, respectively. At the opposite sides to the inlet sides, the fuel rails are interconnected with each other by a connecting pipe. Using this fuel supply system, it is possible to increase a characterisitic frquency of the fuel columns, and to stabilize, suppress, and smooth out pressure pulsation in the fuel rails, thereby reducing uneven fuel injections into the cylinders. The system may have a cam which drives a plunger of a high pressure fuel pump to reciprocate once for every two combustions in two engine cylinders.

A displacement type fluid machine which is easier to machine and assemble than a scroll type fluid machine and has high performance and low cost. A displacer is revolved in a cylinder having an inside wall formed by a curve such that a planar shape is continuous, whereby a working fluid is discharged through a plurality of discharge ports, there is provided a driving unit in which the orbiting radius of the displacer is variable along the shape of a movement line contact portion of the cylinder and the displacer.

Displacement type fluid machine

The present invention enables a scroll fluid machine to have a maximum design volume ratio without increasing an outside dimension of scrolls and allows the basic spiral curve of the scroll to be configured with simple curves. The basic spiral curve of a scroll wrap comprises a group of concentric semicircles, a group of circular arcs having a center different from that of the group of semicircles, and a group of straight lines or curves connecting the group of semicircles and the group of circular arcs together, and a diameter of the outer-most circumferential semicircle of a fixed scroll member is twice as large as radius of the outer-most circumferential circular arc of an orbiting scroll member. In addition, an outer diameter of an end plate of an orbiting scroll is equal to an outer diameter of the outer-most circumferential wrap of the scroll.

Scroll type fluid machine having wraps formed of circular arcs

Growing community of inventors

Tsuchiura, Japan

Kunihiko Takao