Fluid preheating

Abstract

A heating system for preheating a fluid. The heating system comprises a heating unit with a heating flow path; wherein the heating unit is adapted to be operated at a first temperature and to provide a heat transfer between the heating unit and the fluid passing through the heating flow path, with the heat transfer not being sufficient for heating up the fluid passing through the heating flow path to the first temperature.

Description

BACKGROUND ART [0001] 1. Field of the Invention [0002] The present invention relates to fluid preheating. [0003] 2. Discussion of the Background Art [0004] U.S. Pat. No. 5,238,557 describes an apparatus for controlling the temperature of a mobile phase in a fluid chromatographic system which comprises both an ingoing capillary connected to an inlet of a column and an outgoing capillary connected to an outlet of the column. A portion of the ingoing capillary and a portion of the outgoing capillary are arranged in thermal contact with each other to form a contact region wherein heat exchange can occur. In preferred embodiments, liquid leaving the column at an elevated temperature loses a portion of its heat, thus avoiding or at least substantially reducing the transfer of heat to the detector. At the same time, liquid flowing to the column is pre-heated by the liquid leaving the column so that the heating power required for bringing the mobile phase to the desired temperature is reduc...

AI Technical Summary

Benefits of technology

[0010] In a preferred embodiment of the invention, the heating system is used for preheating a fluid before the fluid is supplied to a separation system adapted for separating compounds of a fluid sample. The separation system might e.g. be used for acquiring a peak pattern indicating the composition of the fluid sample, with each of the peaks being related to a certain compound of the fluid sample. By utilizing a heating system according to an embodiment of the present invention, the precision of the separation process is improved. It has been verified experimentally that insufficient heating of the fluid supplied to a separation system leads to an improved quality of the acquired peak pattern. In particular, it has been found that the peak's heights are increased and the peak's half widths are reduced when employing a heating system according to an embodiment of the present invention. Insufficient heating improves the sensitivity of sample analysis. Even tiny amounts of a certain sample compound may be detected.

[0012] A heating system according to an embodiment of the present invention may e.g. be realized by reducing the heating power of the heating unit. Additionally or alternatively, the length of the heating flow path may be reduced until the heat transfer from the heating unit to the fluid becomes sufficiently small. In order to further reduce the heat exchange between the heating unit and the fluid, the number of turns of the heating flow path may be reduced. Another possibility for reducing the heat transfer is to increase the velocity of the fluid passing through the heating unit.

[0017] By implementing a two-stage heating process, the advantages of a heating unit according to embodiments of the present invention may be utilized while providing for reliable overall heating. By utilizing a two-stage heating process, the quality of peak patterns acquired in a separation process may be improved. In particular, the heights of the peaks may be increased and / or the peaks' half widths may be reduced.

[0019] In a preferred embodiment, the heating system comprises a sample injection unit located between the main heating unit and the auxiliary heating unit, with the sample injection unit being adapted for injecting a fluid sample into the fluid passing through the heating system. In this embodiment, the fluid sample is not conveyed through the main heating unit. The fluid sample only has to pass through the auxiliary heating unit. As a consequence, the dispersion of a sample plug is kept small, the half width of the acquired peaks is reduced, and a peak pattern of improved resolution is obtained.

Problems solved by technology

The heating unit is adapted to be operated at a first temperature and to provide a heat transfer between the heating unit and the fluid passing through the heating flow path, with the heat transfer not being sufficient for heating up the fluid passing through the heating flow path to the first temperature.

The heating unit is purposely designed such that the a mount of heat transferred from the heating unit to the fluid does not suffice for bringing the fluid to the temperature of the heating unit.

It has never been considered to purposely design a heating unit with insufficient heating capabilities.

However, it has been found that, when preheating a fluid, insufficient heating might yield superior results.

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