First, we must pay attention to the management and use of instruments and equipment
The high load use of instruments and equipment, often prone to unexpected failures, especially if the optical instrument due to improper maintenance and use of fog, it can not play the normal role of the instrument, and bring work obstacles. Therefore, efficient maintenance and management of instruments and equipment has become an effective means for enterprises and institutions to effectively reduce costs and improve labor productivity. At present, the equipment maintenance and management of domestic enterprises generally stay in the passive repair mode, that is, when the equipment fails and can not continue to use, the maintenance personnel will remove the fault in the shortest time, and when there is no fault, the maintenance personnel are only idle, so this management mode is not efficient, therefore, the management of equipment should also be well planned Similarly, the equipment maintenance management also needs to transform the unplanned work into the planned work. If we regularly check and maintain to reduce the occurrence of faults, especially do a good job in the "Three Prevention" work of the instrument, avoid rush repair work, and ensure that the instrument can be put into normal operation at any time, this is an active way.
Second, pay attention to the anti fog of Surveying and mapping instruments
In the use and storage of Surveying and mapping instruments, in addition to mildew, there is often fog of optical parts, which affects the normal use of the instrument. Therefore, preventive measures can be taken against the main factors of fog of optical signal.
A. Anti fog measures in design and use
A1. Pay attention to anti fog when designing the instrument. The sealing performance of the instrument structure should be strengthened to ensure that the sealing performance of the instrument will not be reduced at high or low temperature, so as to prevent water-based fog caused by air leakage. Designers should pay full attention to the selection of optical glass and materials with good chemical stability, so as to lay a good foundation for anti fog.
A2. In the process of manufacturing and maintenance, attention should be paid to clean production. The workshop for assembly and maintenance should be clean, and the operating procedures should be strictly observed. The optical parts should be carefully wiped. It is strictly forbidden to touch and take the optical parts directly by hand. The tools holding the optical parts should be degreased, and the auxiliary parts used for wiping the optical parts, such as cotton, cloth, ethanol, Yi ether, iodine and the parts contacting with the optical parts The organic gasket must be degreased strictly, the grease content must be controlled, and the utensils containing optical parts and bottles containing ethanol and Yi ether must be cleaned frequently to keep clean. All these are important ways to reduce oil mist.
A3. Reduce the water vapor inside the instrument to prevent the condensation of water vapor on the glass surface. Assemble the instrument under dry conditions or dry the assembled instrument, such as filling dry nitrogen or air and placing desiccant. In the use and inventory of the instrument, the relative humidity of the use environment and the warehouse should be controlled at about 6%. For the field instrument, if it is not good to control the humidity in use, it should be placed in a ventilated, sunny and dry place after use. The desiccant should be put in the instrument box, and attention should be paid to sealing and changing the drying silica gel desiccant in time. In the humid environment, the use of indoor instruments, such as corrector and repeater For the removable lens and precision optical components, take them down in time after use, protect them in the drying cylinder, and keep the instrument clean frequently to reduce fogging.
A4. Reasonable selection and use of grease. All kinds of dust-proof grease and lubricating grease used on optical instruments must be materials with extremely low volatility and good chemical stability. When applying grease on metal parts of optical instruments, first clean the parts, and then apply grease after gasoline volatilization, and apply evenly but not too much. Lubricating oil is prohibited within 10-15mm from optical parts Grease and dustproof grease to prevent oil mist caused by grease diffusion.
A5. To improve the chemical stability of optical glass surface, a layer of hydrophobic film is plated on the glass surface by chemical coating or vacuum coating method, so as to improve the chemical stability of glass, enhance the anti-corrosion ability of glass, and reduce fog. In order to reduce the influence of water-based fog on observation, hydrophilic material can also be used, and a transparent pseudo hydrophilic film with certain physical properties can be plated on the glass surface, so as to improve the chemical stability of glass When the atmosphere is dry, the water in the film will naturally volatilize to the atmosphere.
A6. Remove mildew and mist
Once the optical instrument is mouldy and foggy, it will cause adverse effects, and bring a lot of trouble to the repair work. Therefore, we should focus on prevention, pay attention to the prevention of mildew and fogging from the beginning of instrument design and manufacture, and strengthen the maintenance in the inventory and use of the instrument, which is an important guarantee for the prevention of mildew and fogging. If the instrument has been moulded and fogged, it should be handled in time to avoid greater losses. If the frost fog is only at the initial stage, i.e. after the instrument gets mouldy and foggy, it can be wiped off with mixed solution only in a short period of time when the surface layer of the glass is covered and does not corrode the glass or damage the film. The instrument should be treated in time after fogging, otherwise the surface of optical parts and coating will be corroded, even the glass will be corroded after a long time. It should be scrubbed with general mixed solution or ethyl hydrogen containing dichlorosilane solution in time. This solution can prevent fogging and has a certain effect of demisting and mould removal. Most of the green filters of the multiplexer are phosphate glass, which is easy to fog and hard to clean. You can wash them with dilute ammonia water, then wash them with water, and then wipe the filter surface with mixed solution in time. However, this kind of glass is very unstable. If it is not used, wipe it and put it in a drying dish, or fog it in time, otherwise it will get moldy and fog. Try to avoid wiping silicate glass with alkaline materials, because alkali has corrosive effect on silicate. If the optical parts are seriously mouldy and foggy, and the glass has been corroded, only replace the glass or polish the optical parts again. In a word, the optical instrument should focus on prevention, and the mildew fog should be removed in time. After removing the mildew fog, the anti fog and anti mildew measures should be taken in time to protect the instrument and make it play a greater role.
B. Causes and hazards of fog in optical instruments
Fog refers to the polished surface of optical parts, showing a "dew" like substance, some of these substances are composed of oily dots, known as oily fog, some are formed by water droplets or water and glass chemical reaction accumulation, known as water-based fog: some optical parts, there are two kinds of fog, called water oil mixture fog, generally exist in the glass as "dew" or dry accumulation On the surface of glass. Oil mist is usually distributed at the edge of the optical element and extends to the center, while some are distributed along the wiping traces. The formation of oil mist is mainly caused by the grease polluting the glass surface, or by the diffusion of grease, volatilization and condensation on the glass surface. For example, the auxiliary material used to wipe the optical element has high grease content, or the tool used has grease, which can be taken directly by fingers And touching optical parts will cause oil mist, or the chemical stability of the grease used on the optical instrument is not good, resulting in diffusion or improper use, too much oil will spread to the optical parts and cause oil mist, or the volatility of the grease is very high, oil vapor will be generated and oil mist will be formed, and there is no oil mist when cleaning the metal parts with gasoline Have to let the gasoline fully play clean on the oiled assembly. In some cases, gasoline is used to dilute the dust release grease and apply it to the mirror body. With the increase of time and the change of temperature, these gasoline and other components will gradually volatilize to the optical parts and form oil mist.
The water-based fog is formed by the humid air under the temperature change, which is mainly distributed in the whole area of the parts. The main reason is caused by the humid gas, but it is related to the sealing performance of the instrument, the chemical stability of the optical glass, and the cleanliness of the glass surface. Under the high relative humidity, the mold is easy to grow, and some mold will grow around the mycelium when it grows large Secretions, some of which are liquid, form water mist around the liquid secretions. No matter what the cause of the fog, because the droplets are distributed on the surface of the optical parts with a very small radius of curvature, the incident light is scattered, which not only reduces the effective transmittance of the instrument, but also makes the image quality poor and affects the observation. Due to long-term fogging of some optical parts, a lot of micropores are formed on the corroded glass surface, which will make the glass parts scrapped seriously. Fogging of optical instruments not only exists seriously in the southeast of China, but also in the dry areas. Due to the change of temperature difference, fogging also occurs, which is more difficult to prevent than mildew of optical instruments.
B1. Use antifogging materials to prevent the instrument from fogging
The antifogging material of optical instrument is required to have good antifogging effect without affecting the optical performance of glass. The following hydrophobic film material can play a good antifogging role.
B2. Use antifogging agent
Using ethyl hydrogen containing dichlorosilane to treat the optical glass parts with and without electroless double transparent film can form a relatively firm film, which has hydrophobic property, good waterproof fog property, and easy to form a film. At the same time, coating on the surface of optical parts can improve the mechanical properties of the glass, protect the glass surface from scratch to a certain extent, and improve the chemical stability of the optical glass surface Use it to clean glass, decontamination ability is strong, it is easy to remove fingerprints, saliva ring, improve work efficiency, this is a good antifogging agent. When used, ethyl hydrogen containing dichlorosilane is prepared with anhydrous Yi ether, the concentration of which is 0.25% - 1% (weight%) by weight. The film is formed and cured quickly at room temperature. Gas phase method, dip method, immersion method and cleaning method can be used. It is easy to use and does not need additional equipment. However, it should be noted that due to its pungent smell, the ethyl hydrogen containing dichlorosilane should not touch the skin and clothes when it is prepared. When it is used, it should be dipped with cotton ball or sponge, and not touch the metal. If it is used for optical parts without coating and marking, its concentration can be increased to 4%. As the ethyl hydrogen containing dichlorosilane is corrosive to water or moisture, it should be sealed and stored to prevent damage to the glass For corrosion with metal, the solution should be prepared and used immediately. Phosphate glass should not be treated in this way. P-nitrophenoxyethyl hydrochlorosilane, a kind of brown liquid, can also be used as antifungal and antifogging agent. It is easy to be hydrolyzed. The drug can be prepared into 5% concentration solution with Yi ether, and the film can be formed by centrifugation, soaking and wiping. In addition, the ethyl hydrogen silicone oil and dodecyltrimethoxysilane antifogging agent can effectively play the role of antifogging.
B3. Vacuum coating method is used to coat poly (perfluoroethylene propylene), which is an inert fluoroplastic with high chemical stability, heat resistance, cold resistance and corrosion resistance. It has strong binding force with glass and metal, and has good anti mildew and anti fogging performance. It can not only form a protective film on the surface of ordinary glass, but also form a protective film on the surface of phosphate glass. The chemical stability of phosphate glass is very poor, and it is easy to get moldy and foggy. Moreover, it can not form a solid protective film by coating silane, silicone oil, silicon fluoride materials, etc. with the general chemical coating method. The vacuum coating method is to coat phosphate glass first Magnesium fluoride, and then plated with poly gold fluoroethylene propylene, has a good anti mildew and anti fogging effect on phosphate glass. Most of the green filters of multiplexer are phosphate glass. The filter treated by this method has a good anti mildew and anti fogging effect.
B4. Use non vulcanized silicone rubber sealing putty to prevent fog
The non vulcanized silicone rubber is a kind of non vulcanized ether silicone rubber, which is composed of fillers, colorants and structure control agents. Its high and low temperature sealing performance is significantly better than that of the original sealing wax, and other indicators are not lower than that of the sealing wax.
Third, the conclusion
Due to the rapid development of science and technology and the needs of world economic development, new scientific and technological achievements are constantly applied to instruments and equipment, the modernization level of equipment is constantly improving, and modern equipment is developing towards high speed, precision and automation. Therefore, we should actively introduce foreign modern instrument and equipment management theories and methods, and explore ways to catch up with the international advanced level, Make the management of optical instruments and equipment into a healthy modern management stage.
