The maintenance and maintenance of experimental instruments is an important part of laboratory management work. Doing a good job of instrument maintenance and maintenance is related to the intact rate of the instrument, the utilization rate and the rate of experiment teaching, and the success rate of the experiment. Therefore, as experimental teachers, they should understand the general knowledge of maintenance and maintenance of teaching instruments, and master the basic skills of maintenance and maintenance. Once the instrument absorbs dust and dirt, it not only affects the performance of the instrument, shortens the service life, directly affects the experimental effect, but also affects the appearance and the physical and mental health of the experimenter. The instrument will be covered with dust and dirt during use or storage, so it is mainly dustproof and antifouling. Frequent dust removal and cleaning is an important part of good instrument maintenance and maintenance. (1) Dust removal The dust is mostly tiny dust particles with a small amount of static electricity. It often floats in the air and moves with the air flow. It will adhere to the object and almost permeate. Dust attached to the model specimen will affect its color, dust on moving parts will increase wear, dust on electrical appliances, severe cases will cause short circuit, leakage, valuable dust on precision instruments, serious cases will make the instrument scrapped. There are many ways to remove dust, mainly depending on the condition of the dust surface and the degree of dust adhesion. In the dry air, if there is less dust or the dust has not been dampened and become a patch, you can use a dry cloth to wipe, towel brush, soft brush brush and other methods to remove the dust on the general instrument; Blowing and dusting of the ear-washing ball pump can also be used to vacuum the dust; the dust in the diagonal and the slit can be combined to remove the dust. However, for expensive precision instruments, such as optical instruments, instrument heads, etc., dust removal by the above method will also damage the instrument. At this time, special dust removal tools should be used for dust removal, such as wiping with lens paper and cotton balls with alcohol. When the air is humid and the dust has formed a scale, the dust should be wiped with a damp cloth. Dirt in the diagonal and the seam can be removed with a sharp, soft strip first, and then wiped with a damp cloth, but for discolored surfaces and electrical appliances Do not wipe with a damp cloth. If the dirt is not easy to clean, you can wipe it with a cotton ball moistened with alcohol or ether, or clean it. The instrument will be stained with greasy, glue, sweat and other dirt, and it will produce rust and mildew stains during careless storage and storage. These dirts will have an extremely bad impact on the life and performance of the instrument. The purpose of cleaning is to remove dirt on the instrument. Generally, there are two types of cleaning methods for instruments. One is mechanical cleaning methods, that is, shoveling, scraping, and brushing. The other is chemical cleaning methods, which is cleaning with various chemical decontamination solvents. The specific cleaning method depends on the condition of the surface to which the dirt adheres and the nature of the dirt. The following describes the cleaning methods of several common instruments and parts of different materials. 1. Glassware cleaning There are roughly two types of dirt attached to 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, no matter what kind of dirt is attached to the glassware, the used utensils should be cleaned immediately. Glassware filled with sugar, salt, starch, muddy sand, alcohol and other substances can be cleaned by washing with water. It should be noted that if the attached dirt has dried hard, the vessel can be soaked in water for a period of time, and then brushed with a bristle brush until washed. Glassware is contaminated with oil or animal and vegetable oil, and can be washed with detergent, detergent, detergent, etc. and formulated detergent. When cleaning, brush with a brush. This detergent can also clean glassware with organic oil. After washing the glassware with detergent, it should also be rinsed with clean water. For glassware attached with tar, asphalt or other high-molecular organic substances, organic solvents such as gasoline and benzene should be used for cleaning. If it is still difficult to wash, you can soak the glassware in alkaline detergent for a period of time, and then wash it with a solution of sodium carbonate, sodium bicarbonate, sodium hydroxide or sodium phosphate with a concentration of more than 5%, or even heat it. . In chemical reactions, metals, oxides, acids, alkalis, etc. are often attached to the walls of glassware. When cleaning, according to the characteristics of the dirt, use strong acid or strong alkali to clean or use the method of neutralizing chemical reaction to remove the scale, and then rinse it with water. When using acid-base cleaning, special attention should be paid to safety. The operator should wear protective gloves with rubber gloves; use tweezers, clips and other tools during operation, and cannot take the utensils by hand. In addition, wash the glassware, and finally apply a towel to wipe off the water attached to it. 2. Optical glass cleaning Optical glass is used in the lens, lens, prism, slide, etc. of the instrument. It is easy to get oil, water-wet dirt, fingerprints, etc. during manufacturing and use, which affects the imaging and light transmittance. When cleaning optical glass, different cleaning agents, different cleaning tools, and different cleaning methods should be selected according to the characteristics of dirt and different structures. Lenses coated with anti-reflection coatings, such as those of cameras, slide projectors, and microscopes, can be cleaned by preparing a cleaning agent with about 20% alcohol and about 80% ether. When cleaning, use a soft brush or cotton ball with a small amount of cleaning agent, and make a circular motion from the center of the lens to the outside. Never immerse this type of lens in a cleaning agent; the lens must not be wiped with force, otherwise it will scratch the AR coating and damage the lens. The method of cleaning the prism and plane mirror can be carried out according to the method of cleaning the lens. Mold on the surface of optical glass is a common phenomenon. When the optical glass grows mildew, the light will scatter on its surface, making the image blurry and unclear. In severe cases, the instrument will be scrapped. The reason for the mildew of optical glass is that the surface is covered with microbial spores. When the temperature and humidity are suitable and there are "nutrients", it will grow quickly and form mildew spots. It is particularly important to prevent mildew and stains on optical glass. Once mildew occurs, it should be cleaned immediately. To eliminate mildew stains, molds can be cleaned with 0.1-0.5% ethyl hydrogen dichlorosilane and anhydrous alcohol. A small amount of ether should be added in wet or damp weather, or propylene oxide, Dilute ammonia and other cleaning. Using the above cleaning agent can also clean the grease mist, water-wet mist and oil-water mixed mist on the optical glass. The cleaning method is similar to the method of cleaning the lens. 3. Cleaning of rubber parts There are many parts made of rubber in the experimental instrument. As a high-molecular organic substance, rubber will aging after being contaminated with greasy or organic solvents, causing parts to deform and become soft and sticky. Oil stains will reduce the friction coefficient and cause slipping. For cleaning oil stains on rubber parts, alcohol, carbon tetrachloride, etc. can be used as cleaning agents, but organic solvents cannot be used as cleaning agents. When cleaning, wipe with a cotton ball or silk cloth dipped in cleaning agent first, after the cleaning agent naturally volatilizes. It should be noted that carbon tetrachloride is toxic and harmful to the human body, and it should be cleaned under good ventilation conditions, and pay attention to safety. 4. Cleaning of plastic parts There are many types of plastics, such as polystyrene, polyvinyl chloride, nylon, and plexiglass. Plastic parts are generally very sensitive to organic solvents. When cleaning dirt, organic solvents such as gasoline, toluene, and acetone cannot be used as cleaning agents. It is suitable to wash plastic parts with detergent prepared with water, soapy water or washing powder. 5. Derusting of steel parts Iron and steel parts are very susceptible to corrosion. To prevent corrosion, steel parts in teaching equipment products are often coated with a protective layer of oil, paint, etc., but even so, corrosion often occurs. To remove the corrosion of steel parts, different methods should be adopted according to the degree of corrosion and the characteristics of the parts. For large size, low precision or mechanical methods of rust removal, it is not easy to remove steel parts. You can use chemical methods to remove rust. For example, use a concentration of 2 to 25% phosphoric acid to soak the parts to be removed. It is suitable to 40 ~ 80 ℃, after the rust is removed, the surface layer will form a protective film, then take out the parts and soak in the concentration of 0.5 ~ 2% phosphoric acid solution for about an hour, and finally take out drying can. If this kind of chemical method is used to remove rust in the laboratory, if the operation is slightly improper, it will damage parts, especially precision parts. Therefore, in the laboratory, chemical methods should not be used for rust removal, but mechanical rust removal methods should be used, that is, the rust layer on the parts should be removed by shoveling, picking, scraping, etc., then sanded and polished with sandpaper, and finally Apply a protective layer. Cosmetic Bag,Makeup Pouch,Travel Makeup Bag,Drawstring Makeup Bag Ningbo Happiness Stationery Industrial & Trading Co Ltd , https://www.cnhappiness.com
(2) Cleaning
For the parts made of non-ferrous metals and their alloy materials, the derusting method can refer to the derusting method of steel parts.
However, two points should be noted. First, when using chemical methods to remove rust, different chemical rust removers should be formulated and used according to the chemical characteristics of the parts materials; second, the corrosion of parts made of non-ferrous metals and their alloys should be removed, Generally, mechanical derusting method is suitable.