Abstract: 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.

Abstract: A gradient liquid feed pump system capable of liquid feed in a correct mixing ratio even in the case of liquid feed in which the mixing ratio varies. Specifically, it comprises a first plunger pump for sucking and delivering an eluate, a second the first and second plunger pumps through a cam, a first pressure sensor for measuring the pressure in the flow path of the second plunger pump, a second pressure sensor for measuring the pressure in the fist plunger pump, a cam position detecting sensor for detecting the cam position, wherein when the cam position is in a delivery interval, the rotary speed of the motor is increased, and the period for decreasing the rotary speed is determined on the basis of the difference between the pressure values obtained from the first and second pressure sensors, respectively. Thereby, liquid feed can be smoothly effected with correct mixing ratio while avoiding pressure interference between pumps.

Abstract: The invention provides a mixer capable of mixing two kinds of liquids with each other while varying a mixing ratio in a wide range of the flow rates thereof by causing the two liquids in trace amounts to come into contact with each other, or a mixer capable of mixing in short time. The mixer comprises a mixing chamber very low in profile for effecting mixing reaction, and micro-nozzles, provided at a high density in the upper face and lower face thereof, respectively. The mixer is a mixer wherein micro-nozzles are provided in the inner walls of a mixing chamber, respectively, so as to oppose each other, and two liquids are spurted from the micro-nozzles, respectively, thereby implementing mixing by taking advantage of a diffusion phenomenon. Since the two liquids in trace amounts are ejected from the micro-nozzles, respectively, in such a way as to oppose each other, the two liquids in trace amounts come into contact with each other, thereby enabling diffusion mixing in short time.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A gradient liquid feed pump system capable of liquid feed in a correct mixing ratio even in the case of liquid feed in which the mixing ratio varies. Specifically, it comprises a first plunger pump for sucking and delivering an eluate, a second the first and second plunger pumps through a cam, a first pressure sensor for measuring the pressure in the flow path of the second plunger pump, a second pressure sensor for measuring the pressure in the fist plunger pump, a cam position detecting sensor for detecting the cam position, wherein when the cam position is in a delivery interval, the rotary speed of the motor is increased, and the period for decreasing the rotary speed is determined on the basis of the difference between the pressure values obtained from the first and second pressure sensors, respectively. Thereby, liquid feed can be smoothly effected with correct mixing ratio while avoiding pressure interference between pumps.

Abstract: The invention provides a mixer capable of mixing two kinds of liquids with each other while varying a mixing ratio in a wide range of the flow rates thereof by causing the two liquids in trace amounts to come into contact with each other, or a mixer capable of mixing in short time. The mixer comprises a mixing chamber very low in profile for effecting mixing reaction, and micro-nozzles, provided at a high density in the upper face and lower face thereof, respectively. The mixer is a mixer wherein micro-nozzles are provided in the inner walls of a mixing chamber, respectively, so as to oppose each other, and two liquids are spurted from the micro-nozzles, respectively, thereby implementing mixing by taking advantage of a diffusion phenomenon. Since the two liquids in trace amounts are ejected from the micro-nozzles, respectively, in such a way as to oppose each other, the two liquids in trace amounts come into contact with each other, thereby enabling diffusion mixing in short time.

Abstract: 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.

Abstract: 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.

Abstract: 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 diretion 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.

Abstract: A flow cell is provided with a cell body having an inlet flow passage, a detection flow passage, an outlet flow passage, and windows fixed to the cell body on both sides of the detection flow passage. The inlet flow passage is formed by inserting in and closely contacting a tube in and to a hole formed in the cell body, respectively.

Abstract: In a low pressure gradient liquid chromatograph, two eluting liquids are transferred while they are being mixed with each other, whereby the mixing ratio thereof is changed with time. The mixing is performed by alternately opening and closing check valves provided in the liquid passages of the eluting liquids during a time period corresponding to the actual suction stroke of a plunger pump. The mixing ratio is determined by the time periods during which the check valves are opened, respectively. A detector is provided for detecting the pressure of the mixed liquid and the timing for opening and closing the check valves is changed in accordance with the detected pressure.

Abstract: In a pump in which dual plunger is reciprocated with cams attached to the rotating shaft of a motor, the delivery pressure of liquid is measured during a certain period in each cycle of the pump. By setting the pressure during the certain period as a standard pressure value, the motor is controlled so that the delivery pressure during the remaining period in each cycle approaches to the standard pressure value. In this pump, rotating-speed-priority control and pressure-priority control are alternatingly performed to decrease pulsation during delivering liquid.

Abstract: A casing structure for chromatograph having a plurality of casings respectively installing at least a separating column, a sample inducing portion and/or a detector portion of the chromatograph and the casings are vertically stacked one on another or horizontally juxtaposed one to another. The casing structure further comprises a passage for installing reagent feed pipes therein, and the passage is respectively provided in respective side portions of the casing for communicating with that of another casing when in the stacked state or in the juxtaposed state, and has an inner hole at an inner side thereof for connecting the reagent feed pipes to a pipe connecting portion arranged in the casings, and the passage has a cover at an outer side thereof for being opened outside of the casing.

Abstract: The volume of the sample added to the sample retainer and the capacity of the sample retainer are compared, and the less one is stored as volume of the sample injected to a sample separating column. If the volume of the sample added to the sample retainer is more than the capacity of the sample retainer, accordingly, the capacity of the sample retainer is stored.