Oxygen and Hydrogen Analyzers Common Faults and Handling Methods

Oxygen and Hydrogen Analyzer Common Faults and Handling Methods 1. The lower electrode of the pulse furnace section 1.1 can't lift properly 1.1.1 Lower electrode There are two gas inlets and outlets under the upper and lower gas cylinders. The gas inlet of the lower gas inlet, the piston of the gas cylinder rises, and the upper gas outlet exhausts, otherwise the cylinder The piston drops. If the PTFE pipe connected to the upper and lower air inlets breaks and leaks due to aging [1], the cylinder piston cannot work normally. The instrument is normal after replacing the PTFE pipe. If the non-PTFE tube is broken, the lift switch does not respond. After the inspection, it is found that the lift switch does not touch the position. After the switch is replaced, the lift is normal.

1.1.2 When the lifting switch is pressed, the lower electrode vibrates and drops. Carefully apply a small amount of vacuum grease to the rubber ring of the lower electrode. Note that the lower electrode should not stick to vacuum grease during operation.

1.2 When the upper and lower electrodes burn severely, the graphite electrode holder and the upper and lower electrodes will wear out because the furnace is often in a high temperature environment. The graphite electrode holder must be replaced in time. If this is not the case, the first possibility is that there is a gap between the crucible and the upper electrode, or even no contact, so that no current flows and the instrument does not work. The second phenomenon will surely occur. The graphite electrode holder and the lower electrode have voids and poor contact. The electrode holder will burn badly for a long time until it is scrapped. In order to avoid the above phenomenon and extend the service life of the upper and lower electrodes, we generally perform the inspection after 200 to 300 times of analysis and must replace the graphite electrode holder.

1.3 There is no current in the current analysis process during the analysis. The problem is certainly that the electrodes are in poor contact in the furnace. However, the specific issue of which part needs the operator to carefully observe the troubleshooting. First, see if there is porosity between the plastic gaskets between the upper and lower parts of the furnace, and then clean the upper electrode and the lower electrode dust. Electrode dust accumulates, affecting conduction, even without current. How much dust in the oven depends on the power setting. The general analysis should be cleaned once after 20 times. If there is more dust, the cleaning interval should be shortened. Burning of components in 1.2 will also have no current during the analysis.

2. During the analysis of the measurement section 2.1, the curves appear double peaks. The result is abnormal due to the sample in the heated molten graphite crucible, in which the release of H and O is incomplete (Fig. 1). By properly increasing the melt release current or prolonging the melting time, the O and H can be completely released to meet the measurement requirements. After each analysis, the sample in the crucible is observed and the molten state is good (no bubbling or spitting).

2.2 analysis process, the curve down, the result is low This is due to incomplete degassing process instrument (Figure 2). The degassing process is a process in which the O, H combined inside the graphite crucible and the air entering the furnace chamber are discharged from the body by a high-pressure carrier gas (nitrogen gas). This process is the basis for ensuring the accuracy of the measurement result, and there are three parameters for controlling the process. One: Degassing/analyzing gas flow, degassing current and degassing time. Appropriate atmospheric flow, degassing current, or extended degassing time can be more thoroughly degassed. However, the increase in gas consumption caused by the increase in atmospheric flow rate increases the cost of analysis, and the high temperature caused by excessive degassing current or degassing over time will reduce the service life of the electrode in the furnace. Both must be taken into account and constantly adjusted. Analytical instruments have been used for more than five years. Before each sample was analyzed, an empty firing (without opening the electrode) was performed and degassing was completed.

2.3 Oxygen tailing during the analysis of severe oxygen set the minimum analysis time is 45 seconds, the maximum analysis time is 120 seconds, and sometimes the oxygen analysis time will exceed 120 seconds, or even does not terminate, then check the high before connecting the oxygen detector Magnesium chlorate water absorbent found agglomeration, replacement of magnesium perchlorate reagent tubes and quartz wool, tailing disappeared. It is impossible to re-bake the magnesium perchlorate. If the magnesium perchlorate particles in the reagent tube are not loose, the magnesium perchlorate will saturate. The reagent is saturated before it is completely agglomerated and the properties have changed. As a rule, generally after 100-200 analyses, inspections are performed and must be replaced.

2.4 The analysis process shows that there is no water flow or the path temperature is too high If the analyzer confirms that there is no water flow during the analysis, the following message is displayed: There is no water flow! This is because the analysis system has no current and should stop the analysis. There is a flow indicator on the back of the analyzer. If there is no flow, see if the tube is broken. If you cannot see the flow, the analyzer cannot be confirmed. Since the water is very dirty at this time, the cooling water must be replaced. If the furnace is too hot during the analysis, the following message will appear: The temperature is too high! The furnace temperature should be guaranteed below 70°C. In this case, the second stage cooling system is tap water. If the temperature is higher than 70°C, The electrode will be damaged. When we routinely maintain the instrument, we often pay attention to the position of 5# in Figure 4 (tap water inlet) to prevent filter clogging.

2.5 After the completion of the analysis, the sampler does not stop rotating. This is due to the incorrect sequence of operation of the instrument after the analysis is completed. In the work gap, if the work is interrupted temporarily because of lunch, the main power switch can be in the 2 position. If the work is finished after a day, or when it is not working for a long time, the main power switch should be set to position 1. So that the analyzer can maintain a long-term constant temperature, the next time you turn on it does not need to wait for constant temperature, during the constant temperature period (main power switch is at 1), the loss of power consumption is negligible. After the main power switch reaches the 2 position, wait 10-15 minutes for the analysis to work. When the analyzer is not working for 7 days or a week. The main power switch should be turned off and the analyzer designed for long-term operation. therefore. Long-term work will not be damaged. Before turning the main power switch from position 2 to position 1, the instrument software is now exited; otherwise, the instrument rotation will not stop during the default operation of the instrument.