Maintenance and maintenance of laboratory equipment is an important part of the laboratory management work, improve the maintenance and maintenance of the instrument, the relationship between the instrument's rate of completion, the utilization rate and the rate of experimental teaching, the relationship between the experimental success rate. Therefore, as a laboratory teacher should know the general knowledge of teaching instrument maintenance and maintenance, master maintenance and maintenance of basic skills.
The instrument once adsorbed dust, dirt, not only affect the performance of the instrument, shorten the service life, directly affect the experimental effect, but also affect the aesthetics and the physical and mental health of the experimenter. Instruments in use or storage will be stained with dust and dirt, to achieve dust and dirt mainly, often dust cleaning is an important part of good maintenance and maintenance of the instrument.
(a) in addition to the dust
Dust is mostly with trace electrostatic particles of dust, often floating in the air, with the air flow and move, when the object will be attached to it, almost pervasive. Dust attached to the model specimens will affect the color, moving parts on the dust will increase wear and tear, electrical appliances on the dust, serious short-circuit, leakage, valuable precision instruments on the dust, serious instruments will be scrapped.
Remove the dust in many ways, mainly depending on the dust attached to the surface of the situation and the degree of dust attached. In the dry air, if the dust is less or dust has not been dampened into a block spot, can be used to wipe a dry cloth, towel duster brush, soft bristles brush, etc., to remove the dust on the general instrument; on the internal dust of the instrument can be used PiKi, earball pump blowing dust, vacuum cleaner vacuum cleaner can also be used; on the corners, seams in the dust can be a combination of the above methods in addition to the dust. However, for valuable precision instruments, such as optical instruments, instrumentation meter head, etc., with the above methods of dust will also damage the instrument, this time should be used in special dusting tools dust, such as lens paper wipes, dipped in alcohol cotton ball wiping and so on.
In the humid air, dust has formed a block of dirt, dust should be used to wipe a wet cloth, the corner, the seam in the dirt can be used to sharpen the soft large strip to remove, and then wipe with a wet cloth, but the color of the surface, electrical appliances should not be wiped with a wet cloth. If the gray dirt is not easy to wipe clean, can be dipped in alcohol cotton balls for wiping, or cleaning.
(B) cleaning
Instruments in use will be stained with grease, glue, sweat stains and other dirt, in the storage and custody of inadvertent rust, mold, these dirt on the life of the instrument, the performance will have an extremely negative impact. The purpose of cleaning is to remove the dirt on the instrument. Usually there are two types of instrument cleaning methods, one is the mechanical cleaning methods, that is, with a shovel, scraping, brushing and other methods of cleaning; the second is the chemical cleaning methods, that is, with a variety of chemical decontamination solvent cleaning. The specific cleaning method depends on the condition of the dirt attached to the surface and the nature of the dirt to decide. The following describes several common instruments and different materials parts of the cleaning method.
1. glassware cleaning
Attached to the glassware on the dirt there are two categories, one is water can be cleaned, the other is the need to use detergents or special detergents can be cleaned. In the experiment, no matter attached to the glassware on the dirt belongs to which category, used utensils should be cleaned immediately.
Sugar, salt, starch, mud, alcohol and other substances in the glassware, water can be rinsed to achieve the purpose of cleaning. It should be noted that, if the attached dirt has dried hard, can be soaked in water for a period of time, and then use the brush side of the brush, until clean.
Glassware stained with oil or plant and animal oil, available laundry detergent, detergent powder, detergent and other detergents formulated for cleaning. Cleaning should be brushed with a brush, with this detergent can also be cleaned with oil glassware. Glassware with detergent cleaning, should also be rinsed with water.
For glassware with tar, asphalt or other polymer organic matter, organic solvents should be used, such as gasoline, benzene and other cleaning. If it is still difficult to wash, you can put the glassware into the alkaline detergent soak for a period of time, and then with a concentration of more than 5% of sodium carbonate, sodium bicarbonate, sodium hydroxide or sodium phosphate solution, and even can be heated to clean.
In the chemical reaction, often the glassware wall with metal, oxide, acid, alkali and other dirt. Cleaning, should be based on the characteristics of the dirt, with strong acid, strong alkali cleaning or move to neutralize the chemical reaction method of descaling, and then rinse with water. The use of acid and alkali cleaning, should pay special attention to safety, the operator should bring rubber gloves protective goggles; operation to use tweezers, clamps and other tools, can not use the hand to take and put the utensils.
In addition, wash the glassware, the last application of the towel will be attached to the water dry.
2. Optical glass cleaning
Optical glass is used for instrument lenses, lenses, prisms, slides, etc., in the manufacture and use of oil, water wet dirt, fingerprints, etc., affecting the imaging and light transmission. Cleaning optical glass, should be based on the characteristics of the dirt, different structures, the use of different cleaning agents, the use of different cleaning tools, the choice of different cleaning methods.
Cleaning the lens coated with a transmittance enhancement film, such as cameras, slide projectors, microscopes, the lens, available about 20% of the alcohol formulated cleaning agent for cleaning. Cleaning should be soft brush or cotton ball with a small amount of cleaning agent, from the center of the lens outward as a circular motion. Do not soak such lenses in the cleaning agent cleaning; cleaning lens shall not be wiped hard, otherwise it will scratch the permeability enhancement film, damage to the lens.
The method of cleaning prisms and flat mirrors can be carried out in accordance with the method of cleaning the lens.
Optical glass surface mold, is a common phenomenon. When the optical glass moldy, light scattering on its surface, so that the imaging fuzzy, serious cases will make the instrument scrap. Optical glass mold is mostly due to its surface with microbial spores, in the temperature, humidity, and there is a need for ″nutrients″, it will grow rapidly, the formation of mold. It is particularly important to do a good job on the optical glass mold and dirt, once the mold should be cleaned immediately.
Eliminate mold spots, cleaning mold can be used 0.1 ~ 0.5% of the ethyl-hydroxydichlorosilane and anhydrous alcohol formulated cleaning agent cleaning, or propylene oxide, dilute ammonia and other cleaning.
The use of the above cleaning agents can also be cleaned on the optical glass grease fog, water wet fog and mixed oil and water fog, the cleaning method is similar to the method of cleaning the lens.
3. Rubber parts cleaning
The experimental instruments made of rubber parts, rubber as a polymer organic, greasy or organic solvents will be stained after aging, so that the parts produce deformation, softening viscous; made of rubber drive belt, if stained with oil will make the coefficient of friction decreases, resulting in slipping phenomenon.
Cleaning rubber parts on the oil, available alcohol, carbon tetrachloride, etc. as a cleaning agent, and can not use organic solvents as cleaning agents. Cleaning, the first cotton ball or silk cloth dipped in cleaning agent wipe, to be cleaned after the natural volatilization of cleaning agent can be. It should be noted that carbon tetrachloride has a toxic, harmful to the human body, cleaning should be carried out under better ventilation conditions, pay attention to safety.
4. Plastic parts of the cleaning
There are many types of plastic, polystyrene, PVC, nylon, plexiglass and so on. Plastic parts are generally very sensitive to organic solvents, cleaning dirt, such as gasoline, toluene, acetone and other organic solvents can not be used as a cleaning agent. Cleaning plastic parts with water, soap and water or washing powder formulated detergent scrubbing is appropriate.
5. Steel parts rust
Iron and steel parts are very easy to rust, in order to prevent corrosion, teaching instruments in the product of steel parts are often coated with oil, paint and other protective layers, but even so, rust still often occurs. Remove rust and corrosion of steel parts, should be based on the degree of rust and corrosion, as well as the characteristics of the parts using different methods.
On the larger size, precision is not high or mechanical methods to remove rust is not easy to remove the net steel parts, chemical methods can be used to remove rust, such as the concentration of 2 ~ 25% of the phosphoric acid soak parts to remove rust, soak the temperature to 40 ~ 80 ℃ is appropriate, to be removed from the corrosion of the net, the surface of the formation of a layer of protective film, and then take out the parts to be immersed in the concentration of 0.5 ~ 2% phosphoric acid solution for about an hour, and finally remove the drying can be. hours, and finally remove the drying can be.
In the laboratory to use this type of chemical method of rust removal if the operation is slightly improper, the reverse will damage the parts, especially precision parts. Therefore, in the laboratory, in addition to rust should not be more chemical methods, and should be used to remove rust mechanically, that is, the first shovel, ticking, scraping and other ways to remove the rust on the parts of the layer block, and then sandpaper sanding, polishing, and finally coated with a protective layer.
For non-ferrous metals and their alloy materials constitute the parts, the rust removal method can refer to the rust removal method of steel parts. But should pay attention to two points, one, the use of chemical methods to remove rust, should be based on the chemical properties of parts and components of the preparation and use of different chemical descaling agent; and second, to remove non-ferrous metals and their alloys constitute the parts of the corrosion, the general use of mechanical descaling method is appropriate.