Gas chromatograph
AssigneeShimadzu Corporation
InventorsKazuya Nakagawa, Toyoaki Fukushima
Life of this patent
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Abstract
A target pressure is calculated by a fluid dynamic theory using a length of the column, an inner diameter of the column and the temperature of the column so that the linear velocity of the gas flowing through the column is at a preset pre-determined value at which the HETP (height equivalent to a theoretical plate) value, as calculated from chemical kinematic theory, is the minimum and the resolution of the column is the highest. Then the pressure of the gas at the entrance of the column of a chromatograph is maintained at the calculated target pressure while the temperature of the column is raised to reduce the analyzing time.
Claims12
A gas chromatograph comprising:
- a pressure regulator under variable control via electrical input signals for regulating a pressure of a gas at an entrance of a column of the gas chromatograph;
- a pressure sensor for detecting a pressure of the gas at the entrance of the column;
- calculating means for calculating a target pressure of the gas at the entrance of the column from a length of the column, an inner diameter of the column and a temperature of the column, the target pressure being such a pressure that a linear velocity of the gas flowing, through the column is at a preset pre-determined value;
- and
- a controller with electrical output signals for controlling the pressure regulator so that the pressure detected by the pressure sensor is maintained at the target pressure.
A method of performing an analysis using a chromatograph including a column, the method comprising the steps of:
- calculating a target pressure of a gas at an entrance of the column from a length of the column, an inner diameter of the column and a temperature of the column, the target pressure being such a pressure that a linear velocity of the gas flowing through the column is at a preset pre-determined value;
- and
- controlling the pressure at the entrance of the column to be maintained at the target pressure.
Dependencies are inferred from the claim text.