Daily Maintenance Of Optical Emission Spectrometer

1. Cleaning Of Condenser Lens:
 
The concentrating lens is the only channel through which the sample is excited to enter the spectrometer, and the mirror must be kept clean. However, long-term use of the concentrating mirror will be polluted, and a layer of brownish brown matter will adhere to the outer surface. The longer the time, the thicker the deposit. The metal powder generated by the excitation also adheres to the outer surface of the lens, reducing the transmittance of light, and lowering the absolute light intensity of all elements, especially the far ultraviolet elements C, P, and S are more obvious. The slope of the working curve of the element can be lowered, the sensitivity of the analysis is also lowered, and the analysis error is increased. Therefore, it is necessary to clean up the system on a regular basis, and how much time to clean up. It depends on how many tasks are analyzed. It is best to clean up once in 180 days. The specific cleaning methods are as follows:
First prepare a mixture of ether and ethanol (1:1), absorbent cotton and lens paper, then open the outer casing of the instrument, then slowly pull out the lens plate outwards, then remove the lens fixing plate and expose the condenser. The surface of the concentrating mirror is exposed with absorbent cotton, and a mixture of diethyl ether and ethanol is applied to the outside of the concentrating mirror. If the pollution is serious, rub it a few times, until the dirt is wiped off and then wipe the watermark with a dry cotton ball.
Note: The lens is a heated component, be careful!
In particular, the concentrating mirror is made of quartz. You can't use a hard object (you must never use a metal clip to clamp the cotton) to avoid scratching the lens surface. In particular, some instruments for the analysis of nitrogen, the lens material is MgF, the texture is soft, and it is extremely deliquescent, and must be wiped with solvent acetone.
Clean the lens, do not touch it with your fingers, so as to avoid fingerprints and affect the light transmittance.
 
 
2. Cleaning Of Excitation Table:
 
The sample produces a large amount of metal vapor during the excitation process. A portion of the metal vapor exits the instrument with argon, and the remaining portion adheres to the inner wall of the spark chamber, causing serious contamination. A metal compound is also attached to the reverse side of the metal and ceramic gasket, and a large amount of powder is deposited on the bottom. This serious pollution reduces the insulation performance between the two electrodes and affects the excitation effect. In particular, when an alloy containing a low melting point element is excited, a low melting point metal volatile is sprayed on the surface of the shaft of the spark chamber porcelain insulating sleeve. In severe cases, the two poles can be directly short-circuited, and the high-voltage insulation part of the electrode holder is burned out, causing the instrument to be inoperable and affecting production.
There are two cleaning methods, one is to use the excitation gap. When it is found that there is a large amount of powder in the inner wall of the spark, the steel brush is directly cleaned. At this time, it is not necessary to remove the cover plate, and the electrode is directly cleaned by a steel brush, and the metal powder is washed and blown at a large flow rate after cleaning. If the indoor wall of the spark is seriously polluted, thoroughly clean it. Remove the electrode cover, remove the tungsten electrode, and wash it with a mixture of alcohol and ether. Generally, the low-melting-point metal adhesion layer is not easily rubbed off, and it is necessary to add cerium oxide or iron oxide polishing powder, which can be wiped off after polishing. After cleaning, put on the good pole cover, install the cleaned electrode, set the distance of the analysis gap, use the distance gauge, rinse for several minutes, and ignite the sample several times until the excitation spot is agglomerated.
 
 
3. Electrode Cleaning:
 
The electrode used in the full-spectrum optical emission spectral analysis process uses a tungsten electrode as the excitation electrode depending on the material to be analyzed. After the analysis is excited once, the metal powder on the tip of the electrode is generally gently brushed with a tubular tungsten wire brush. During use for a period of time, the attachment of the electrode tip increases, affecting the change in the analysis gap distance, and it is necessary to clean the tungsten electrode. The tungsten electrode is generally hard, and the surface layer is lightly polished with a metallographic abrasive paper of about 700. After cleaning, measure the distance of the gap.
The cleaning of the electrode holder and the electrode is generally cleaned once when the excitation is performed 1000 times. It is preferable to carry out simultaneously with the collecting lens.
 
 
4. Argon System Before Factory Debugging
 
The argon system has been adjusted before leaving the factory. Generally, the fault is not easy to occur, but the use of the gas circuit control element will be blocked by the regular use. The aging of the sealing element will also cause the pipeline to leak. Therefore, it needs to be inspected once a year or so.
 
5. Exhaust emission system
 
In order to keep the filter bottle clean, clean the filter bottle approximately every two weeks and replace it with clean water. In addition, the clean tube of the filter bottle is cleaned once a week and kept clean.
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