GC TCD detector troubleshooting - gas chromatograph
1, the bridge current fault The TCD carrier gas through the premise, open the bridge current switch, current control knob for adjusting the bridge. Bridge current should be transferred the predetermined value stable. If the adjustment is not incorporated into current tune up, particularly the thermal conductivity cell at high temperature, the current adjustment less than the rating of the bridge, the bridge can looked into to be less than current book value of transferred fault.
Such malfunctions are the following: thermal conductivity unit not connected to the connection; thermal conductivity of your pool open hot wire disconnected or lead; bridge Power Supply Faulty; bridge configuration circuit disconnect or current meter is faulty.
2, the baseline zero fault Bridge current transfer good and stable, respectively, zero adjustment of the thermal conductivity of the knob, so that the baseline on the recorder instructions back to zero. If you adjust the knob, issue how how, no change or adjust the baseline are less than zero is considered to have zero thermal conductivity of failure.
Zero thermal conductivity fails to fault the following causes are several: hot wire resistance, or lead an incorrect asymmetry; hot wire create wall, or serious pollution; zero potentiometer lead open circuit; Recorder Open or no response; Double Air Road traffic by a lot.
Thermal conductivity can not rule out zero failure, according into the following steps:
(1) attenuation block test: the discovery of set up a baseline shift compared to zero, it really is going decay with all the small into the largest block adjustment to see whether the gradual lowering of deviation at a baseline.
(2) the role of zero knob check: each spin of brute force, in small knob, observe perhaps baseline feedback.
(3) two-way flow check: In the gas line leak testing based along the use of soap film gas flow meters were tested two-way flow of value, see if that much difference.
(4) between the hot wire resistance error check: on top of the hot wire thermal conductivity cell levels socket for terminal resistance Measure. In general, the resistance group the distinction between the hot wire mustn't be
0.2 ~ 0.5 , as beyond this value, shall be (6) proper care.
(5) hot wire right wall or smear: hot wire hot wire proper into a wall and also by measuring the insulation resistance between the cell body to be confirmed. Hot wire for the serious stain on the thermal conductivity cell by cell body
Cleaning and removing or part of the elimination for this specific steps to surf the cleaning of a detector.
(6) hot wire or lead an inaccurate asymmetry: Gas is required occurs your market repair of thermal conductivity cell circuit, the experience of such situations need to carefully check link between the hot wire pinout. Correct
The hot wire connected in several form a bridge, and bridge 2 arms belonging to the heat on just the same air journey.
(7) two-way traffic by very much or pneumatic leak treatment: two-way flow of difference is too big can be controlled by adjusting the pneumatic valve to be resolved, but this time there should be two vent gas line
Leakage. (8) open-zero routine. (9) recorder open or no solution.
3, the baseline noise and drift
Cause instability in the baseline thermal conductivity detector are many reasons, some dozens of species common are:
(1) power voltage is just too low, or fluctuations in the power strain on the same phase change too much;
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