Maintenance and maintenance of experimental instruments

Understand the maintenance and maintenance of the instrument is a basic skill that users should have, because the maintenance and maintenance of the instrument is related to the integrity of the instrument, the usage rate and the success rate of the experimental teaching. Therefore, the maintenance and maintenance of the instrument can be described as a part of the use of instruments in experiments and production

Once the instrument absorbs dust and dirt, it not only affects the performance of the instrument, shortens the service life, directly affects the experimental results, but also affects the aesthetics and the physical and mental health of the experimenter. Therefore, dust removal and cleaning are the highlights of instrument maintenance.

(1) Dust removal

Most of the dust is tiny dust particles with a small amount of static electricity, which often float in the air, move with the airflow, and the object will adhere to it, almost no holes. Dust attached to the model specimen will affect its color. Dust on the moving parts will increase the wear and tear on the electrical parts. If there is dust on the electrical appliance, it will cause short circuit and electric leakage. The dust on the precious precision instrument will cause the instrument to be scrapped.

There are many ways to remove dust, mainly depending on the condition of the dust-attached surface and the degree of dust adhesion. In the dry air, if the dust is less or the dust has not been wetted into a patch, use a dry cloth wipe, a towel brush, a soft brush, etc. to remove dust from the general instrument;唧, ear-washing air pump blowing dust, dust can also be vacuumed; dust in the diagonal, seam can combine the above several methods to remove dust.

However, for valuable precision instruments, such as optical instruments, instrument heads, etc., dust removal by the above method will also damage the instrument. In this case, special dust removal tools should be used to remove dust, such as wiping with lens paper and wiping cotton balls with alcohol.

When the air is damp and the dust has formed into a scale, the dust should be wiped with a damp cloth. The gray scale in the diagonal and seam can be removed with a sharpened soft strip, then wiped with a damp cloth, but the surface is faded. Do not wipe with a damp cloth. If the dirt is not easily wiped clean, wipe it with a cotton ball dampened with alcohol or ether, or wash it.

(2) Cleaning

The instrument will be stained with greasy, glue, sweat and other dirt during use. It will cause rust and mildew spots when stored and stored inadvertently. These dirt will have extremely bad effects on the life and performance of the instrument. The purpose of cleaning is to remove dirt from the instrument. Generally, there are two types of methods for cleaning the instrument. One is mechanical cleaning, that is, cleaning by shovel, scraping, brushing, etc.; the second is chemical cleaning, that is, cleaning with various chemical decontamination solvents. The specific cleaning method depends on the condition of the dirt adhering surface and the nature of the dirt. The cleaning methods for several common instruments and different material parts are described below.

1, glassware cleaning

Glassware is divided into general glassware and special glassware.

There are two types of dirt on the attached glassware. One type can be cleaned with water, and the other type must be cleaned with a cleaning agent or special detergent. In the experiment, the used utensils should be cleaned immediately, regardless of the type of dirt attached to the glassware.

Glassware filled with sugar, salt, starch, mud, alcohol, etc., can be washed with water to achieve cleaning purposes. It should be noted that if the attached dirt is already dry, the vessel may be soaked in water for a period of time, and then brushed with a brush until it is washed.

Glassware is stained with oil or animal oil, and can be washed with detergent, detergent, detergent, etc. Brush with a brush when cleaning, and use this detergent to clean glassware with organic oil. After the glassware is washed with detergent, it is also rinsed with water.

For glassware with tar, bitumen or other high molecular organics, it should be cleaned with organic solvents such as gasoline and benzene. If it is still difficult to wash, the glassware can be immersed in an alkaline detergent for a period of time, and then washed with a solution of sodium carbonate, sodium hydrogencarbonate, sodium hydroxide or sodium phosphate at a concentration of 5% or more, or even heated. .

In chemical reactions, metals, oxides, acids, alkalis, and the like are often attached to the walls of glassware. When cleaning, it should be cleaned by strong acid, strong alkali or by neutralization chemical reaction according to the characteristics of the dirt, and then rinsed with water. When using acid and alkali cleaning, special attention should be paid to safety. The operator should wear rubber gloves and protective glasses. Use tools such as tweezers and clips when handling.

Mildew on the surface of optical glass is a common phenomenon. When the optical glass is moldy, the light scatters on its surface, making the image unclear. In severe cases, the instrument will be scrapped. Most of the causes of optical glass mold are due to the presence of microbial spores on the surface. When the temperature and humidity are appropriate, and there is a desired "nutrient", it will grow rapidly and form mildew. It is especially important to make mold and stain resistant to optical glass. Once mold spots are generated, it should be cleaned immediately.

To eliminate mildew, clean mold can be cleaned with 0.1~0.5% ethylhydrogen dichlorosilane and anhydrous alcohol. It should be mixed with a small amount of ether in wet weather or cleaned with propylene oxide, dilute ammonia or the like. .

The oily mist, the water-wet mist, the oil-water mixed mist, and the like on the optical glass can also be cleaned by using the above cleaning agent.

2, the cleaning of rubber parts

There are many parts made of rubber in the experimental equipment. As a kind of polymer organic matter, rubber will age after being greasy or organic solvent, causing the parts to be deformed, soft and sticky; the transmission belt made of rubber, if Oil stains will reduce the coefficient of friction and cause slippage.

To clean the oil on the rubber parts, alcohol, carbon tetrachloride or the like can be used as a cleaning agent, and an organic solvent cannot be used as a cleaning agent. When cleaning, first wipe with a cotton ball or silk cloth cleaning agent, after the cleaning agent is naturally evaporated and cleaned. It should be noted that carbon tetrachloride is toxic and harmful to human body. It should be carried out under good ventilation conditions during cleaning. Pay attention to safety.

3. Cleaning of plastic parts

There are many types of plastics, such as polystyrene, polyvinyl chloride, nylon, and plexiglass. Plastic parts are generally sensitive to organic solvents. When cleaning dirt, organic solvents such as gasoline, toluene, acetone, etc. cannot be used as cleaning agents. It is advisable to wash the plastic parts with water, soapy water or washing powder.

4, steel parts rust removal

Steel parts are extremely rust-resistant. To prevent corrosion, steel parts in teaching instruments are often coated with protective layers such as oil layers and paints, but even so, rust often occurs. To remove the corrosion of steel parts, different methods should be used according to the degree of corrosion and the characteristics of the parts.

For large size, low precision or mechanical rust removal, it is not easy to remove steel parts. Chemical methods can be used to remove rust. For example, immersing parts with phosphating with a concentration of 2 to 25% phosphoric acid. It is suitable to 40~80 °C. After the rust is removed, a protective film will be formed on the surface layer, and then the component will be taken out and immersed in a phosphoric acid solution with a concentration of 0.5 to 2% for about one hour, and finally taken out and dried.

In the laboratory using such chemical methods, if the operation is slightly improper, it will damage the parts, especially the precision parts. Therefore, in the laboratory, it is not advisable to use chemical methods for descaling, but mechanical rust removal method, that is, removing the rust layer on the parts by shovel, picking, scraping, etc., then sanding and polishing with sandpaper, and finally Apply a protective layer.

For parts made of non-ferrous metals and their alloy materials, the descaling method can be carried out by referring to the descaling method of steel parts. However, two points should be noted. First, when chemical rust is used, different chemical rust removers should be prepared and used according to the chemical characteristics of the component materials. Second, the rust of parts made of non-ferrous metals and their alloys should be removed. Generally, a mechanical descaling method is preferred.

Finally, the author has to swear that the instrument has a longevity and cannot be used endlessly. In order to effectively extend the life of the instrument, it is not only dependent on cleaning, but also on careful maintenance.