Infrared carbon analyzer failure analysis and maintenance

Failure l: Sulfur signal pointer does not move. There is also no sulfur analysis on the screen.

Analytical maintenance: This situation occurs after a six-day outage period, so all the reagents in the glass tube (imported magnesium oxysulfate, domestic alkali asbestos) and absorbent cotton in the dust filter should be replaced first. And clean the high frequency combustion furnace. Retest machine, no improvement.

Open the left side cover of the instrument, observe the actual situation of the terminal and analyze the electronic system. There are four ICs and Ic4 integrated blocks, all of which are 2ULN2803A. The Ic and Ic4 two integrated blocks, pins 1–6, do not work on the circuit. In order to prevent some sudden external electrical impulses from passing through these feet and to interfere with the normal operation of the electronic system, these feet can be cut off. In fact, we only removed Ic. 1 - 6 feet, the instrument will return to normal.

Fault 2: The accuracy of the sulfur analysis is poor and the reproducibility is poor.

Analytical maintenance: This phenomenon has occurred several times in five years. Connect the computer to see the sulfur working curve. In the part below the zero point, the part below the zero point is not integrated into the analysis result, and because the difference below the zero point is somewhat different, the accuracy of the analysis result is poor and the reproducibility is also poor, except for sweeping the high-frequency combustion. Furnace, change all the reagents, adjust the zero level of sulfur, it is better to clear the electronic system and re-calibrate the working curve.

The steps to clear the memory of the electronic system are as follows:

(1) Put the main switch in 1st gear;

(2) Open the combustion chamber;

(3) Remove the cover on the left side of the instrument;

(4) Unplug the cable plug connected to the electronic system;

(5) Press and hold the reset button on the bottom panel of the electronic system for at least 30s;

(6) Restore the initial state of the system;

(7) Update the calibration.

After taking the above-mentioned measures, the failure phenomenon disappears, and the instrument recovery positive measurement technology 2001No8 often.

Fault 3: In the analysis process, the high-frequency combustion furnace suddenly buzzed.

Analytical maintenance: This situation is also more than one time. It occurs in the continuous process of making a large number of pig iron samples. Due to the burning of pig iron samples, there are more dust and splashes. When the burner cover is opened, it can be seen that there is a dust spray at the end of the analysis of the sample, and a lot of dust will blow out when the sample is sprayed. At this time, immediately shut down and timely clean the high-frequency combustion furnace, check whether the copper brush in the quartz tube in the furnace and the type 0 rubber gasket used for sealing need to be replaced, and check whether the reagent in the glass tube and the absorbent cotton in the dust filter need to be replaced. These reagents and absorbent cotton for a long time will lead to poor air flow, causing the dust to spray. After these processing failures disappear, the instrument returns to normal.

Fault 4: The pointers of the carbon and sulfur signal tables do not return to zero. No analysis results were found for carbon and sulfur.

Analysis and maintenance: According to maintenance program block diagram 1. Open the left cover, in the case of power-on, first check the infrared tank rectifier, it is cold, and then use a multimeter to measure the two external test points of the three infrared emitters that are chained together, the voltage is 6V (DC), the resistance is * . Normally, the resistance of each infrared emitter is only 10, indicating that at least one of the three infrared emitters is damaged, resulting in an open circuit. Turn off the power of the host computer, disconnect the connection line between the infrared emitters, and measure the resistance one by one. Only the resistance of the two terminals of the infrared transmitter is *, and it is judged that it is damaged. When replacing the new parts, it was discovered that the infrared lamp in the original infrared emitter had one pin and the round ring solder joints were detached and rewelded, and the instrument returned to normal.

Fault 5: At the beginning of the analysis, the tubular fuse in the main unit is blown.

Analysis and maintenance: As viewed from the back of the instrument, there are two tubular fuses in the lower right corner of the back of the instrument. The fuse holder is not the same as the domestic and external screw-type holders. It requires a tool to unscrew the fuse holder cover and remove two fuses. A 15A fuse was blown.

There are four causes for the fuse to blow:

(1) triac breakdown;

(2) Damage to high voltage transformers;

(3) Damage to high voltage rectifiers;