Metal sleeve glass high efficiency atomizer inspection procedures and standards
Flame atomic absorption spectrometry
I. Inspection tools:
Air flow meter, pressure gauge, atomic absorption spectrometer, oil-free air compressor, acetylene gas, stopwatch, measuring cylinder (10mL), distilled water (or purified water), Cu standard solution.
2. Inspection procedures and standards:
1. Remove the atomizer and check the appearance: there should be no damage or crack in the glass part, the metal welding part is smooth and there is no trachoma, the steel needle and other bonding parts are firm, the steel needle is not bent and loose, and there is no air leakage on the tail side. . Is the inlet capillary (5 in total) complete?
2. Connect the air supply pipe to the atomizer inlet pipe and tighten the lock nut. There must be no air leakage. Adjust the air compressor output pressure to the pressure specified by the atomic absorption manufacturer's design.
3. Check the air flow: connect the atomizer with the inspection device provided by our company, and adjust the pressure to the atomic absorption manufacturer's set pressure with the lower right switch. At this time, look at the flowmeter and set the value for the atomic absorption manufacturer. The upper and lower access is qualified at 5%. If it is unqualified, please return it to the manufacturer for replacement, and the user cannot adjust it.
4. Open the gas source, insert the sampling tube into the distilled water, hold the atomizer with the hand so that the direction of the air rod is the same as the actual air intake direction on the atomic absorption. Drain the distilled water and see the spray state. For the front spray, the diffused surface should be larger than 8cm, and the mist should be sprayed out from the range of 3400 (about 200 points of the impact ball strut), and the spray amount should be basically the same in all directions. If the spray angle or atomization is not good: the angle of the impact ball can be rotated. It must be held by the base of the impact ball (with a rubber ring). Otherwise, the connection rod can be broken. The impact ball can be arbitrarily within 90 degrees below the connecting rod. Adjust, (guarantee the impact ball struts are below, so that the water drops can be discharged smoothly), and the impact ball is tightly pressed to the atomizer nozzle to see the spray state, until satisfactory.
5. When spraying, the sound of the atomizer should be consistent. There should be no sudden, sudden, sudden or sudden sound. If there is intermittent sound, please check if the injection tube is inserted firmly (plugged into the injection tube to exclude), whether the injection tube is There are leaks (replacement of the sample tube). If it still cannot be ruled out, the atomizer is not leaking tightly, which is a substandard product and is replaced by the manufacturer.
6. Check the lifting amount: Insert the sample tube into the 10mL measuring cylinder, fill the measuring tube with distilled water to the engraved line, measure the lifting amount, and start the spray calculation. Generally, the lifting amount of the atomizer is 4-6mL/min, such as The lifting amount is small, the sampling tube can be replaced, or the sampling tube can be shortened (reducing the injection resistance), and the atomizer should be kept from clogging. If the clogging is eliminated, please see the following troubleshooting and maintenance, if the lifting amount exceeds Indicators, can be replaced with a sample tube or a long injection tube (increased injection resistance).
7. Sensitivity check:
(1) Adjust all the measurement conditions of atomic absorption, adjust the position of the burner, install the qualified atomizer, make the atom absorb the position where the energy can be seen, adjust the energy to reach 100%, and open the air source. Inhalation of distilled water, when the energy of the instrument is reduced (caused by spray light), the energy of the instrument can be reduced to less than 50%, which is a qualified product, the more the better, the better.
(2) Ignition inspection absorbance: After the above inspection is completed, the ignition sensitivity and relative standard deviation (RSD) can be checked. The sensitivity can be checked by absorbance. Generally, 1μg/mL Cu element is used for inspection. The absorbance is above 0.18A for qualified products, (with atom The absorption comprehensive performance is related, and the sensitivity absorbance is also different. The lower limit is not less than 10%.
8. Dynamic stability check (RSD), instrument ignition, inhalation of 2μg/mL Cu element after zero adjustment with distilled water, 11 times by continuous integration method, each measurement time is 3 seconds, then calculate the relative standard deviation RSD, Less than 0.8% is qualified, which is related to the stability of the host, and the host baseline must be stable.
9. The atomization efficiency should be no less than 8%. (according to JJG 694-1990)
3. Troubleshooting and maintenance
1. Constriction of the restriction tube: usually blocked at the inlet, can be removed with your fingers, or blown with compressed air.
2. When the sample solution will be exhausted, a series of bubbles will form in the tube. The resistance will be large to stop the inhalation. Use the finger to bounce the inlet tube to make the bubble suck away. It can be normal, and the bubble can be sucked away by the syringe.
3. The inner tube of the atomizer is blocked: it is often blocked near the nozzle. Remove the impact ball cap and blow off the blockage with compressed air in the opposite direction. If it can't be blown, use a small fire (lighter) to bake the front nozzle, then immediately Blowing, basically solve the blockage problem. Remember to never use wire smash, otherwise it will damage the atomizer, and the company will not be responsible for the warranty.
4. The airflow passage of the nozzle is blocked, and the impact ball is removed and blown in the opposite direction by the compressed air. A slight blockage can be used to block the front spout and allow the airflow in the duct to blow out.
5. The inner tube or air flow channel of the nozzle is blocked by dust or dry salt accumulated by organic matter. The impact ball cap can be removed and inserted into the sulfuric acid-potassium dichromate solution heated to the smoke for a few seconds. After cooling, rinse with water. If it is used for more than half a year or if the air flow is reduced, it should be treated as such.
6. After each measurement, use distilled water (not available tap water) to spray for more than 30 seconds to clean the pipeline to prevent the solution from clogging.
7. The working room temperature should not be lower than 10 degrees, otherwise the cooling effect of the spout can cause icing blockage.
8. If the main engine has a passage for auxiliary gas, the auxiliary combustion gas should be turned off, otherwise the combustion gas that is not involved in the spray can reduce the sensitivity. Excessive flow of gas helps not only consume more gas, but even flames.
9. The impact balls cannot be interchanged between all nebulizers, otherwise the sensitivity is greatly reduced.
10. All nebulizers damaged during mailing are replaced by the manufacturer. Damages in violation of the above methods of use are not included in this column.
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