Some standard content:
National Standard of the People's Republic of China
Technical Code for Dust Control in Foundry
Dust control code for foundryUDC 614.8: 628
GB 895988
This code is specially formulated to prevent dust hazards in foundry workshops, make the labor hygiene conditions of foundry production meet the national industrial hygiene standards, protect the health of employees and protect the environment.
This code is applicable to the design and management of dust control in foundries. Enterprises that produce foundry equipment and provide services for foundries should also refer to it. Measures should be taken in the process and equipment for foundry dust control. Processes and equipment that do not generate or generate less dust pollution should be used. All processes and foundry equipment that generate pollution should be equipped with dust control facilities, and dust removal devices should be installed when the dust concentration in the air discharged to the outside exceeds the national or local emission standards.
In addition to complying with this regulation, the dust prevention work in the foundry workshop shall also comply with the current national GBJ19--87 "Heating, Ventilation and Air Conditioning Design Code", GBJ36-79 "Industrial Enterprise Design Hygiene Standard", GB4-73 "Industrial "Three Wastes" Emission Standard" and other relevant standards and specifications.
1 Dust prevention process measures
1.1 Process layout
1.1.1 The layout of process equipment and production flow should be considered comprehensively based on production program, metal type, process level, factory site and factory conditions, etc. combined with dust prevention technology. It is advisable to make the fixed work station in a well-ventilated and relatively clean place in the workshop. 1.1.2 The molding and core making sections with less pollution should be arranged on the leeward side of the minimum frequency wind direction in the non-heating season in the centralized heating area, and on the leeward side of the minimum frequency wind direction throughout the year in the non-central heating area. 1.1.3 The sand treatment and cleaning sections should be separated from other parts of the workshop by light materials or solid walls. The sand treatment and cleaning sections of large casting workshops can be arranged in separate workshops. 1.1.4 When limestone sand molding technology is used, the pouring area should be arranged in a well-ventilated location in the workshop. 1.1.5 The processes of assembling and removing dust, sand dropping, unpacking, sand cleaning, grinding, cutting, welding and other processes should be fixed at fixed work stations or sites to facilitate the adoption of dust prevention measures.
1.1.6 When the cleaning workbenches of large-scale production lines are arranged in rows, they should be separated from each other. 1.1.7 When arranging process equipment and process flow, necessary conditions should be provided for the reasonable arrangement of dust removal systems (including air duct laying, platform location, dust collector setting, centralized dust transportation and treatment or sludge removal, etc.). 1.2 Process Equipment
1.2.1 For all standard casting equipment that generates dust pollution (such as sand mixers, sand screens, belt conveyors, shot blasting and cleaning equipment, etc.), the manufacturer should be equipped with closed covers, and non-standard equipment should be designed with dust prevention facilities. 1.2.2 Mechanized devices should be used for weighing, feeding and adding materials for furnace charge preparation. 1.2.3 The transportation of bulk dry materials should be closed, pipelined, mechanized and automated to reduce transfer points and shorten the transportation distance. Manual loading and unloading or grabbing should not be used. 1.2.4 Belt conveyors that transport bulk dry materials should be equipped with closed covers. 1.2.4.1 When the belt conveyor is used for inclined transportation, it should not exceed its maximum allowable inclination angle according to different materials and dust prevention requirements. 1.2.4.2 The belt conveyor should be equipped with a head cleaner (when a magnetic separation pulley is used, a magnetic separation cleaner should be attached) and an empty section cleaner.
1.2.4.3 When the discharge height is greater than 1.0m, the inclined chute should be used to discharge to the lower belt conveyor, and a closed material guide trough should be set at the receiving point. Approved by the National Bureau of Standards on April 1, 1988
Implementation on November 1, 1988
GB 8959-88
1.3.5 Sand preparation and sand treatment production should be closed and mechanized. 1.2.6 Large amounts of powdered auxiliary materials should be transported in containers (bags) or tank trucks with good sealing properties. After arriving at the foundry, pneumatic conveying is used to transport to the silo. The packaging of bagged powder should have good sealing and strength. Unpacking and unloading should be carried out on special equipment with ventilation and dust removal measures.
1.2.7 Bulk granular dry material silos should be closed and equipped with material level indicators. 1.2.8 It is not advisable to use a climbing bucket feeder and an external box-type dosing device that generate a lot of dust for sand mixing. It is advisable to use a closed sand mixer with a weighing device.
1.2.9 In batch production, production line operations should be adopted whenever conditions permit. 1.3 Process methods
1.3.1 It is advisable to use a sand process with good disintegration and less harm. When using new processes and new materials, new pollution should be prevented. 1.3.2 It is advisable not to add fluorite to cupola smelting. Low-toxic additives should be used for the smelting of non-ferrous metals. 1.3.3 The structure, fuel and combustion methods of various heating furnaces and kilns should be improved to reduce the amount of smoke and dust emitted. 1.3.4 The recycled hot sand should be cooled and deashed. Different types of coolers are used according to different production rates. 1.3.5 After the dry large casting mold is dropped, the old sand in the sand hopper should be vibrated and magnetically separated, and then sent away by a belt conveyor equipped with a closed exhaust hood.
1.4 Process operation
1.4.1 Furnace materials with less attached impurities should be selected and should be pre-treated. Metal furnace materials should be stored in a place sheltered from rain. Coke should be screened first.
1.4.2 Wet operation should be adopted under the conditions that the process is possible. 1.4.3 When the sand mold is assembled, the method of sucking away the sand particles and floating dust on the surface of the sand mold by connecting the T-type pipe to the compressed air or blowing the sand particles and floating dust on the surface of the sand mold directly with compressed air should not be adopted. If necessary, it should be carried out in a special small room with ventilation. Mobile or centralized vacuum dust collection devices should be adopted. 1.4.4 The exhaust port of the casting should be unobstructed, and carbon monoxide should be ignited during pouring. 1.4.5 When cleaning manually, the temperature of the casting should be below 50℃. 1.4.6 Dry sandblasting should not be used for cleaning the surface of the casting. 1.4.7 In situations where the operating conditions of sand dropping, grinding, cutting, etc. are poor, it is appropriate to use a robot remote control isolation operation. 2 Comprehensive measures for dust prevention
2.1 Building measures
2.1.1 Room location and orientation
2.1.1.1 In central heating areas, foundry buildings should be located on the upwind side of the minimum frequency wind direction in the non-heating season of other buildings. In non-central heating areas, they should be located on the upwind side of the minimum frequency wind direction throughout the year. 2.1.1.2 The main windward side of the room should be perpendicular or nearly perpendicular to the center line of the two quadrants with the highest frequency of wind direction in summer, that is, 60° to 90° with the longitudinal axis of the building.
2.1.1.3 For buildings with L, LJ, or mountain-shaped planes, their openings should face the dominant wind direction in summer and be within the range of 0° to 45°. 2.1.1.4 The main orientation of the building should be north-south. 2.1.2 Plant room spacing and plane form
2.1.2.1 The plane form of the plant should be considered comprehensively in combination with the requirements of architecture, structure and dust prevention while meeting the production and process flow.
When medium and small foundry workshops adopt rectangular plane layout, it should not exceed three spans, and the cleaning section should be separated from other sections. Under the condition of good ventilation and dust prevention measures, the foundry can also adopt multi-span rectangular plant. 2.1.2.2 When the plant plane is LJ or mountain-shaped, the distance between its two wings and other buildings should meet the requirements of natural ventilation. There should be a certain amount of green space around the foundry. 2.1.3 Plant vertical design
2.1.3.1 In addition to designing local ventilation devices, the foundry should also use skylights for exhaust or set up roof ventilators. The skylights of magnesium casting workshops 180
should be rainproof.
The exhaust skylight should be arranged directly above the heat source. GB 8959—88
Storm windows should be installed in the melting and pouring areas; and in the sand falling and cleaning areas. 2.1.3.2 The ends between the windshield and the skylight and between the adjacent skylights of the multi-span workshop as the shelter skylight should be closed, and transverse partitions should be installed every 50 to 60 meters along the length of the skylight. 2.1.3.3 The following skylight forms should not be used: a: high and low span transverse skylights of arched roof trusses; b. The sunken well-type skylights should not be used in the sections where a large amount of smoke and dust is generated, as well as in windy, sandy, cold and snowy areas; c. Ventilated ridges should not be used in the sections where waste heat and smoke are generated. 2.1.3.4 For the side spans with bridge cranes, it is advisable to set window sashes that can be opened and closed at appropriate heights. The cab of the bridge crane located in dusty and high-temperature areas should be closed and insulated, and ventilation and air-conditioning measures should be taken. 2.2 Equipment Sealing
2.2.1 Sealing Principles
2.2.1.1 All crushing, screening, mixing, cleaning and other equipment should be sealed. 2.2.1.2 According to different dust pollution conditions, different sealing methods such as partial sealing, overall sealing and sealed chambers should be adopted. 2.2.1.3 The sealing device should meet the principles of easy operation, disassembly, maintenance, firm structure, light weight, tight fit and safety, and should not lose its tightness due to vibration or impact of material blocks. 2.2.1.4 The sealing cover should adopt a groove structure. 2.2.2 Sealing of moving parts of equipment
2.2.2.1 When two equipments are in dynamic connection, it is advisable to use flexible materials for closed connection. 2.2.2.2. Dust pollution caused by the rotation, vibration or swing of equipment should be sealed by the whole equipment or sealed chamber. 2.2.3 Sealing of other parts
2.2.8.1 Inspection doors should adopt oblique contact. 2.2.3.2 For covers that need to be opened frequently on the horizontal surface, it is advisable to use sand-sealed covers with groove structure. 2.2.3.3 When the drop height of the belt conveyor receiving section at the bottom of the sand falling machine is greater than 2.0m, it is advisable to increase the number of rollers or use support plates instead, and use double-layer sealed exhaust hoods.
2.3 Eliminating the positive pressure of falling materials
2.3.1 To eliminate the positive pressure generated when the material falls, methods such as reducing the drop height, reducing the inclination angle of the chute, adding chute flow isolation devices or corner chute and increasing the volume of the sealed hood should be adopted. 2.3.2 The following measures can be taken to eliminate the positive pressure of the lower receiving belt conveyor a. Connecting pipe - connect the lower positive pressure area and the upper negative pressure area to form a connecting pipe, b. Buffer box - increase the space of the guide trough to form a buffer box, c. Labyrinth baffle - lengthen the guide trough buffer box one by one, and set a labyrinth baffle in it. 2.4 Wet dust prevention and vacuum cleaning
2.4.1 Under the conditions permitted by the process, ground water sprinkling measures should be taken in the dust operation area. Dust pollution in the process of loading, unloading, transportation, crushing, screening, etc. of materials should be dusted by spraying water mist. When using water mist to suppress dust, the following points should be met: a. It is advisable to add a wetting agent to the water;
b. The direction of the water mist sprayed by the nozzle can be parallel to the material flow direction or at a certain angle, c. When arranging the nozzle, care should be taken to prevent water droplets from being sucked into the exhaust system, and should not splash onto the operating parts of the process equipment, d. The distance from the nozzle to the material layer should not be less than 300mm, and the jet width should not be greater than the maximum width of the spatial position where the material is transported.
A rubber curtain should be installed between the exhaust hood and the nozzle. e.
f. The water pressure of the farthest water supply point of the nozzle should be determined according to the nozzle type. 181
GB 8959--88
g. The water valve of the water spray system should be interlocked with the operation of the production equipment. 2.4.2 Steam spray dust suppression is applicable to the dust emission points of the crushing and transportation equipment of coke, coal and old sand. Steam can be saturated steam below 100kPa.
When using steam spray dust suppression, the following points should be noted: a. The steam nozzle can be a circular or rectangular ring pipe, a horseshoe-shaped bifurcated pipe or a straight pipe, and a hole should be drilled on the pipe. b. A valve must be installed on the steam branch pipe, and a pressure gauge must be installed near the nozzle inlet, and a steam trap must be installed at the lowest point at the end of the pipeline; c. Steam valves should be interlocked with process equipment or conveyor control systems. 2.4.3 Vacuum cleaning can be used to remove dust deposited on the ground, walls, equipment, pipelines, building components and trenches. 2.4.4 In the case of large areas and heavy dust accumulation, a centralized vacuum cleaning system should be used. 2.5 Personal protection
2.5.1 The following operations in the casting production process must take necessary personal protection measures in accordance with the relevant regulations of the labor department: a. When operating in front of the steelmaking electric arc furnace using direct furnace exhaust; b. When entering the iron (steel) ladle ingot pit and electric arc furnace for hot repair operations; c. When working in an environment with severe dust pollution. 2.5.2 All types of personal protective equipment used must comply with relevant national standards. 3 Ventilation and dust removal measures
3.1 Furnaces
3.1.1 Electric arc furnaces for steelmaking
3.1.1.1 The exhaust and purification method of electric arc furnaces for steelmaking should be determined by specific analysis and comprehensive consideration of conditions such as smelting process, process layout, furnace type, capacity, plant conditions, water source conditions, labor hygiene, environmental protection, energy-saving requirements and maintenance management level. 3.1.1.2 The following methods should be adopted for exhaust
a. Exhaust outside the furnace:
Upper split umbrella cover -
-less than or equal to 5t electric arc furnace.
Furnace cover exhaust hood - less than or equal to 10t electric arc furnace. Clamp exhaust hood - less than or equal to 10t electric arc furnace. Electrode ring cover - less than or equal to 5t electric arc furnace. Blowing and suction hood - less than or equal to 5t electric arc furnace. The above exhaust methods are applicable to electric arc furnaces without charging holes on the furnace cover, and exhaust hoods should be installed on the furnace doors. Large closed hoods and mobile closed hoods are required to control smoke and dust throughout the smelting process, and the environment requirements are strict. The degree of mechanization and automation is high.
b. Furnace exhaust:
——Electric arc furnaces greater than or equal to 10t.
Disconnected furnace exhaust——
c. Furnace exhaust combined with internal and external exhaust——Electric arc furnaces greater than or equal to 10t. d. Roof exhaust——Electric arc furnaces that require smoke and dust to be controlled throughout the smelting process and have high environmental requirements. It is advisable to combine it with the exhaust methods inside or outside the furnace.
3.1.1.3 The design parameters of the ventilation and dust removal system should be considered according to the maximum flue gas volume during the smelting oxidation period. The exhaust volume should be adjusted according to different smelting periods, and variable air volume measures can be taken to save electricity. 3.1.1.4 For the ventilation and dust removal system with the smoke exhaust method outside the furnace, when the smoke temperature is lower than 135℃, no cooling device may be provided. However, when the furnace cover smoke exhaust hood is used, a water-cooled hood or a heat-resistant steel hood shall be used. 3.1.1.5 For the ventilation and dust removal system with the smoke exhaust method inside the furnace, a cooling device (water-cooled furnace top smoke exhaust pipe, water-cooled air duct, air-cooled air duct or other coolers, etc.) shall be provided. When conditions permit, waste heat utilization may be considered. 3.1.1.6 The smoke purification equipment of the arc furnace should adopt dry high-efficiency dust collectors, such as bag dust collectors and electric dust collectors. Wet dust collectors should not be used.
GB 8959-88
3.1.1.7 Explosion-proof measures shall be taken for the system inside the furnace or the combined system inside and outside the furnace. 3.1.1.8 The ventilation and dust removal system shall have measures to prevent excessively high smoke temperature or hot particles from directly entering the bag dust collector, and preventive measures shall be taken when condensation is possible.
3.1.2 Cupola
3.1.2.1 The exhaust and purification method of the cupola should be determined based on specific analysis and comprehensive consideration of the furnace type, fuel type, charging port opening, water source conditions, labor hygiene, environmental protection and energy-saving requirements, and maintenance management level. 3.1.2.2 The following methods should be adopted for exhaust gas purification: a. Mechanical exhaust gas purification equipment should be adopted:
High-efficiency cyclone dust collector, granular layer dust collector - after the charge is pre-treated (such as waste casting sand removal, coke screening, etc.), it is suitable for areas with dust emission concentration of 200-400mg/m3 (standard state). Bag dust collector, electrostatic precipitator - suitable for areas with dust emission concentration below 200mg/m3 (standard state). Mechanical ventilation dust removal system should be equipped with a low-resistance dry dust removal device in front of the high-efficiency dust collector, such as a settling chamber, general cyclone dust collector, etc. b. Spray dust removal device at the cupola outlet - use natural ventilation and spray device to purify the exhaust gas, suitable for dust Areas with emission concentrations of 400 to 600 mg/m2 (standard conditions). 3.1.2.3 The ventilation and dust removal system of the cupola during the smelting stage should take flue gas cooling measures, such as water-cooled jackets, water-cooled cyclone dust collectors, air-cooled ducts and other coolers. When conditions permit, waste heat utilization can be considered. When environmental requirements are high, the needs of the furnace-building stage should also be considered. 3.1.2.4 The design exhaust volume of the cupola can be considered by multiplying the furnace blast volume by a coefficient of 1.05 to 1.10 plus the air inlet volume of the charging port. The inlet wind speed at the charging port should be 1.0 to 1.2 m/s. 3.1.3 Non-ferrous metal smelting furnaces
3.1.3.1 Various crucible furnaces and induction furnaces for melting copper, zinc, lead, magnesium, and babbitt alloys (Industrial frequency, medium frequency), resistance furnaces, and arc furnaces should all be equipped with ventilation and dust removal systems. Aluminum melting furnaces are only equipped with exhaust devices. 3.1.3.2 The exhaust hoods of non-ferrous metal smelting furnaces should adopt fixed or rotary lifting exhaust hoods, split exhaust hoods, furnace mouth side suction hoods, furnace mouth ring hoods and integrally sealed hoods according to the furnace type, process operation and smoke exhaust requirements. When process conditions permit, the latter three types of hoods should be used. 3.1.3.3 The exhaust volume of various exhaust hoods should be determined according to the type of non-ferrous metals smelted, the furnace type and the hood form. 3.1.3.4 During smelting, if there is dust with recovery value in the flue gas, it should be recovered. When the flue gas contains zinc oxide, a bag dust collector should be used. When it contains zinc chloride or other hygroscopic dust, if a bag dust collector is used, Smooth filter material should be used, and insulation or heating measures should be taken.
3.1.3.5 When fluoride, chloride salt and sulfur are added as covering flux to smelt non-ferrous metals, a large amount of corrosive smoke is generated, and anti-corrosion measures should be taken in the ventilation and purification system.
3.1. Heating furnace and other furnace seals
3.1.4.1 Coal-fired mold drying furnaces, annealing furnaces, etc. should adopt mechanical coal adding and "open flame back burning" and other measures. When the dust emission concentration does not meet the national or local standards, a ventilation and dust removal system should be installed. 3.1.4.2 Flat drying furnaces, vertical drying furnaces, horizontal drum drying furnaces, vibrating boiling sand drying furnaces, etc. used for raw sand drying should be equipped with ventilation and dust removal systems, and measures to prevent condensation and sticky bag blockage should be considered. 3.1.4.3 The loading port of the mold drying furnace should be equipped with an exhaust hood, and the wind speed at the hood port should be 0.5~0.7m/s. The furnace door of the sand core drying furnace should be equipped with an exhaust hood, and the exhaust volume should be calculated based on the wind speed of 0.7m/s at the hood port. 3.1.4.4 The wax melting furnace and roasting furnace for investment casting should be equipped with a fume hood or an exhaust hood at the loading and unloading port, and the wind speed at the hood port should be determined according to the type of wax material. 3.1.4.5 Iron (steel) water-filled drying furnace, plug rod drying furnace, etc. should be equipped with exhaust devices. Asphalt heating furnaces should be equipped with exhaust purification systems. 3.2 Processing and transportation of furnace charges and molding materials 3.2.1 Crushing and grinding equipment
3.2.1.1 The upper part of the crusher: direct feeding, when the height is less than 1m, only a closed hood can be used without exhaust. If the feed is fed by a chute or a grid screen, when the height is greater than or equal to 1m, an exhaust closed hood should be set at the feeding port. The lower part of the jaw crusher discharges to the belt conveyor. When there is exhaust at the upper part and the drop difference at the lower part is less than 1m, the lower part can be equipped with a closed cover without exhaust. Regardless of whether there is exhaust at the upper part or not, when the drop difference at the lower part is greater than or equal to 1m, an exhaust closed cover should be installed at the lower part. 183
GB 8959-88
3.2.1.2 Both the feeding port and the discharge port of the double-roll crusher must be closed for exhaust. When the feeding drop difference is less than 1m, the small roller crusher with tighter sealing can be equipped with exhaust at the lower part without exhaust at the upper part. 3.2.1.3 The feeding port of the irreversible hammer crusher should be more tightly sealed and equipped with an air lock valve. The discharge port should be equipped with an exhaust closed cover, and a natural circulation air duct should be installed on the closed covers of the feeding port and the discharge port. 3.2.1.4 The rotating drum of the ball mill should be installed in a fully closed cover. When feeding the ball mill with a belt conveyor, exhaust is required at the charging port and the ball mill body, of which 2.3 of the air volume is discharged from the body and 1/3 is discharged from the charging port. 3.2.1.5 The wheel mill for preparing coal powder and clay powder needs to be equipped with an exhaust closed enclosure. 3.2.2 Screening equipment
3.2.2.1 The upper part of the flat-bottomed vibrating screen must be closed for exhaust, and the exhaust volume can be calculated based on the opening wind speed of the cover not less than 1m/s. When the upper part cannot be closed, an exhaust hood can be set above the screen and closed with rubber curtains on all sides. At this time, the exhaust volume should be doubled. A closed small room can be used for the flat-bottomed vibrating screen for coke. When the flat-bottomed vibrating screen is used to process hot old sand with water vapor, the exhaust volume should be increased by 40% compared with cold sand. 3.2.2.2 The drum screen and drum crushing screen must be exhausted in an overall closed well, and the exhaust volume should be calculated based on the opening wind speed being at least 50% greater than the circumferential speed of the screen. If the opening area is difficult to calculate, it can also be calculated based on the cross-sectional area of the large end of the sieve of 2300m3/h·m2. 3.2.2.3 The upper part of the electromagnetic vibrating screen should be closed, the main body may not be exhausted, and its feeding port and discharge port should be exhausted. 3.2.3 Old sand cooling equipment
3.2.3.1 The cooling elevator can use a cyclone dust collector. When the outlet concentration exceeds the standard, a second-stage dust collector should be installed. 3.2.3.2 The exhaust volume of the boiling cooler and double-disc stirring cooler can be calculated as 15%~20% larger than its blast volume. When selecting dust removal equipment and arranging dust removal air ducts, condensation and blockage must be avoided. 3.2.4 Sand processing equipment
3.2.4.1 When using a roller or pendulum sand mixer to prepare molding sand and core sand, the quantitative device should be sealed in the main body enclosure and exhausted. 3.2.4.2 The exhaust volume of the closed enclosure of the roller or swing wheel sand mixer should be calculated according to the following conditions: When the airtightness is good, it should be taken according to the wind speed of 0.75~1.0m/s at the opening. a. When mixing the mold back sand with more dust, the exhaust volume should be 30%~40% larger than (above) a. b. For the sand mixer equipped with a cooling blower, the exhaust volume should be 25~30% larger than the blowing volume. c. When the flammable flux vapor is emitted during the mixing process, the minimum exhaust volume of the sand mixer should not be less than the air volume required to dilute the flux vapor to less than 25% of the lower explosion limit. 3.2.4.3 An exhaust hood should be installed at the sand discharge port of the resin sand mixer. The exhaust volume of the thermal resin sand mixer should be 25%~30% larger than the cooling blowing volume.
3.2.4.4 When selecting the dust removal equipment for the sand mixer, the influence of different molding sand processes on the initial dust concentration should be considered. Limestone back sand has high-efficiency two-stage dust removal, dry molding sand has high-efficiency one-stage dust removal, wet molding sand has cyclone dust removal, and wet molding sand for production line has high-efficiency one-stage dust removal.
3.2.4.5 The exhaust vent of the closed enclosure of the sand mixer should make the exhaust air flow direction consistent with the rotation direction of the roller and away from the powder discharge port, otherwise a partition should be installed between the exhaust vent and the discharge port. 3.2.5 Conveying equipment
3.2.5.1 When using mechanized conveying equipment such as belt conveyors, bucket elevators, and screw conveyors to transport foundry sand, a ventilation and dust removal system should be installed. When the weight percentage of water content in the sand is greater than 2.5% and is relatively uniform, exhaust is not necessary. 3.2.5.2 When using belt conveyors to transport granular materials, the following measures should be taken: a. At the transfer point and the terminal unloading point, a local closed hood or volumetric exhaust hood should be installed for exhaust; b. When the situation in 1.2.4.3 is met, the exhaust volume should be increased; c. In the case of scattered transfer points, dust removal units should be used; d. When the plow-type scraper is used to unload into the multi-bucket silo, when the unloading scraper is interlocked with the local closed hood air duct valve, the exhaust volume can be calculated based on the unloading point plus the leakage volume of other points (calculated as 15% to 20% of full opening); when there is no interlock, the exhaust volume can be calculated based on the total of all points fully opened. When the automatic opening and closing side suction hood is used, the exhaust volume can be calculated only based on the unloading point. 184
GB 895988
3.2.5.3 When using bucket elevator to lift new and old sand vertically, the exhaust point should be set according to the following principles: When conveying normal temperature materials (t<50℃), the exhaust should be at the bottom when the lifting height is h<10m; when h>10m, both the upper and lower parts should be exhausted. a.
When conveying hot materials (t=50～150℃), both the upper and lower parts should be exhausted. b.
When conveying high temperature materials (t>150℃), the exhaust should be at the top. c.
d. When the comprehensive working system is in operation, both the upper and lower parts should be exhausted. 3.2.5.4 The closed screw conveyor does not need to be exhausted, and an exhaust hole with filter material (bag) can be opened on the top cover. When the feed drop is large (h>1m), an exhaust hood should be set at the receiving point, and its exhaust volume should be able to eliminate positive pressure. When conveying powder, the wind speed at the exhaust port should not exceed 2m/s. 3.2.6 Silo
3.2.6.1 When using a screw conveyor to feed materials into a closed silo, the following methods can be used for pressure relief and dust removal:. An exhaust hole equipped with filter material (bag) is set on the top cover of the silo. b. When conveying dusty and hot materials, a high-voltage electrostatic dust source control facility can be added to the natural exhaust duct. At this time, the air flow velocity in the duct should be controlled to be less than 3.0m/s.
8.2.6.2 When using pressure feeding to feed materials directly into the silo, the bag dust collector can be directly located on the top cover of the silo. 3.3 Core making and molding
3.3.1 Core making
When using resin sand processes such as shell core, extruded core, hot core box, cold core box, etc. to make cores, an exhaust hood should be installed. 3.3.1.1 The shell core machine should be equipped with an exhaust hood on its upper part, and a rubber curtain should be added to the lower edge of the hood. The exhaust volume can be calculated based on the hood opening wind speed of 1.75m/s. 3.3.1.2 The single-station hot core box core shooting machine can be equipped with a side exhaust hood at the coring location. The two-station hot core box core shooting machine should be equipped with an exhaust hood above the I and II positions (two locations). The exhaust volume can be calculated based on the hood opening wind speed of 1.5m/s. The multi-station hot core box core shooting machine should seal each core box part along the track and exhaust the air. The exhaust volume can be calculated based on the opening wind speed of 0.7~1.0m/s at both ends.
3.3.1.3 The core extruder should be equipped with an exhaust hood above the heating part of the extruded sand core. The exhaust volume can be calculated based on the opening wind speed of 0.7m/s. 3.3.1.4 Cold core box core making should be exhausted during the whole process of sand shooting, air hardening, air cleaning, box opening and core removal. The exhaust volume can be calculated based on the wind speed of 0.75~1.0m/s at the hood opening.
3.3.2 Sand mold and sand core transportation and hot assembly
3.3.2.1 When using oil, synthetic resin binder or resin sand process, when the hot sand mold (core) taken out from the core making machine or sand mold (core) drying furnace is conveyed to the sand mold (core) warehouse or the core distribution box by conveyor, an exhaust hood should be installed on the conveyor. The exhaust volume can be calculated based on the wind speed of 1.0m/s at the openings at both ends of the hood and the loose gap. When conveying hot core box sand cores, an exhaust hood should be added within 10 minutes of the travel of the hanging conveyor.
3.3.2.2 When the sand core is assembled by heat, an exhaust hood should be installed on the assembly roller. The exhaust volume can be calculated based on the opening wind speed of 0.7m/s, or 1250m3/h per meter of roller.
3.3.3 Harmful gas treatment
Harmful gases emitted during core making, molding, drying, transportation and heat assembly should be purified and discharged to the outside when the emission concentration exceeds the standard. Harmful gases can be purified by washing, adsorption and other methods. 3.3.4 Core grinding and spraying
3.3.4.1. A ventilation and dust removal system should be installed for sand core grinding, and coarse particles should be removed by a sedimentation box before purification. The exhaust volume can be calculated at 3 to 6 m3/h per millimeter of grinding wheel diameter.
A hand-push core grinder should be equipped with an exhaust hood that moves with the grinding wheel; a turntable core grinder should be equipped with a side exhaust hood next to the grinding wheel, and a core grinder with a fixed grinding wheel and a moving sand core should be equipped with an exhaust hood next to the grinding wheel of the machine tool. 3.3.4.2 For spraying operations with volatile harmful substances, an exhaust cabinet should be installed for small sand cores, and the exhaust volume can be calculated based on an opening wind speed of 1 m/s. A large sand core should be equipped with an exhaust chamber with a front opening, and the exhaust volume can be calculated based on an opening wind speed of 0.5 to 0.8 m/s. 3.4 Sand dropping and cleaning
3.4.1 Sand dropping
GB 8959—88
3.4.1.1 It is not advisable to adopt on-site sand dropping. When individual extra-large castings need to be unpacked and sand dropped on-site, wet sand dropping by pouring water on the mold and spraying water mist can be adopted to reduce dust, and personal protection should be strengthened.
3.4.1.2 Exhaust hoods should be installed for fixed sand dropping. 3.4.1.3 The exhaust hoods of vibrating sand dropping machines should be of the following types: The sand dropping machines on production lines with a high degree of automation should adopt fixed closed hoods or enclosures, and the exhaust volume can be calculated according to the opening wind speed of 0.6~1m/sa.
b. Sand dropping machines with a capacity of more than 7.5t and a long sand dropping time should use mobile closed hoods. The exhaust volume can be calculated according to 1200~3000m3/h per square meter of lattice plate area. Small sand-falling machines take the larger value, and large sand-falling machines take the smaller value. After the sand-falling is completed, it is advisable to delay opening the mobile hood for 1 to 2 minutes. c. For sand-falling machines less than or equal to 7.5t, semi-enclosed hoods or side suction hoods are suitable. The exhaust volume of semi-enclosed hoods can be calculated based on the opening wind speed of 0.5m/s; the exhaust volume of side suction hoods can be calculated based on the hood opening wind speed of 3.5~5.0m/s. d. For sand-falling machines greater than 7.5t and produced in small batches of single pieces, fixed or top-covered semi-enclosed hoods are suitable. The exhaust volume can be calculated based on the opening wind speed of 0.5~0.8m/s.
e. Medium and small sand-falling machines that require a large degree of freedom in process operation can use blowing and suction ventilation hoods. f. Sand-falling machines with a sand box height of less than 200mm and a casting temperature of less than 200℃ can use bottom exhaust hoods. The exhaust volume can be calculated based on 2000~4500m/h per square meter of lattice plate area. The lower value is used for wet sand with casting temperature below 100℃; the higher value is used for dry sand with higher temperature. 3.4.1.4 The drum sand-falling machine should be equipped with exhaust hoods at the casting outlet and the used sand discharge port. If the height difference at the casting inlet is large, an exhaust hood should also be installed, and the exhaust volume can be determined according to the height difference. 3.4.1.5 The core sand-falling machine should use a mobile closed hood. If the casting temperature is low and the crane is not unhooked, a side suction hood can be used. 3.4.1.6 When the sand-falling machine uses a side suction hood, the lower sand hopper should be exhausted, and the exhaust volume can be calculated as 750m3/h per square meter of the grid plate area. This air volume can be deducted from the exhaust volume of the side suction hood. 3.4.1.7 A ventilation device should be installed in the sand-falling trench. a. When the used sand conveying machinery cannot be exhausted in a closed manner, the trench can be used for comprehensive exhaust. The exhaust volume is calculated based on the wind speed of the trench section of 0.5~0.8m/s.
When the conveying machinery has a closed exhaust, the total exhaust volume can be calculated according to the calculation of a above minus the exhaust volume of the conveying machinery. b.
C. When a slab conveyor is used to transport high-temperature sand castings, the total exhaust volume can be calculated based on the elimination of residual heat. d. Local air supply is recommended at fixed operating stations. 3.4.2 Cleaning
3.4.2.1 The cleaning drum must be well sealed and should be exhausted. For cleaning drums with hollow shafts, the exhaust volume can be calculated based on the wind speed of the hollow shaft hole of 20~23m/s; for non-standard drums without hollow shafts, a fully enclosed exhaust hood should be installed outside the drum. 3.4.2.2 The exhaust volume of the shot peening cleaning room can be calculated based on the cross-sectional wind speed of 0.12~0.5m/s perpendicular to the airflow. The lower value is used for large shot peening rooms and surface cleaning of castings; the higher value is used for small shot peening rooms and for rough cleaning of castings. 3.4.2.3 The exhaust volume of the shot blasting cleaning room can be calculated according to the number of shot blasting heads when the shot blasting volume of each shot blasting head is 140kg/min. The first shot blasting head is 3500m3/h, and each subsequent shot blasting head is 2500m2/h. For continuous shot blasting rooms, when both ends cannot be completely sealed, the exhaust volume calculated according to the number of shot blasting heads can be added with 30% of the leakage volume, and the intermittent shot blasting room can be added with 10~15%. When the shot blasting volume of each shot blasting head is greater than 140kg/min, it can be calculated according to the relevant formula.
3.4.2.4 The exhaust volume of the combined blasting cleaning room can be calculated according to the shot blasting room. 3.4.2.5 The airflow organization of the sand blasting room should adopt upward intake, downward exhaust, or one side intake and opposite side exhaust. The exhaust volume can be calculated according to the cross-sectional wind speed perpendicular to the airflow of 0.3~0.7m/s. Small sand blasting rooms take the higher value, and large sand blasting rooms take the lower value. 3.4.2.6 The shot sand separation system of the shot blasting and shot blasting cleaning room should be separated from the ventilation and dust removal system of the room body. 3.4.3 Casting surface cleaning
3.4.3.1 The exhaust volume of the fixed grinding wheel machine can be calculated as 2.0~2.5m3/h per millimeter of grinding wheel diameter. It is advisable to use a grinding wheel machine with a built-in dust removal device.
3.4.3.2 For the hanging grinding wheel machine located on the batch production line, a dust collection chamber can be used. The air velocity at the opening of the chamber should be greater than or equal to 0.8m/s. 186
GB 8959 - 88
3.4.3.3 The cleaning workbench should be equipped with a side exhaust hood. The exhaust volume can be calculated based on the hood opening air velocity of 1.0~1.3m/s. 3.4.4 Casting cutting and welding repair
3.4.4.1. Plasma cutting must adopt local exhaust and personal protection. 3.4.4.2 When cutting the burrs and pouring risers of steel castings with oxygen or acetylene flames, if the height of the pouring risers of the castings is no more than 1m from the grating plate, the pit can be used for exhaust. The pit should be filled with water, and the wind speed on the plate surface should be 1.0-1.2m/s. The larger value should be used for cutting alloy steel parts, and the smaller value should be used for cutting carbon steel parts. When the pouring riser height of the cut casting exceeds 1m, a mobile exhaust hood should be used. 3.4.4.3 Small castings should be welded on a welding workbench. The lower and upper parts of the workbench should be exhausted, and the wind speed of the hood section can be 0.75m/s. Large castings should be fully ventilated for welding.
4 Setting and maintenance of ventilation and dust removal system
4.1 System design
4.1.1 The system division should be convenient for management, operation and safe production. At the same time, if the work and dust properties are the same, a ventilation and dust removal system can be used together. When working at the same time and the dust properties are different, but different dusts are allowed to be mixed and recycled or the dust has no recycling value, a ventilation and dust removal system can also be used together. When there is a danger of combustion or explosion after mixing different dusts, and when dust-containing gases with different humidity and temperature are mixed and condensation may occur, a ventilation and dust removal system shall not be used together.
4.1.2 When the hood of the sand-falling machine is different from the lower part of the sand hopper of the sand-falling machine, the ventilation and dust removal systems used should be separated. The mobile closed hood and the sand-falling machine should be electrically interlocked.
4.1.3 The layout of the ventilation platform should be relatively concentrated, and the convenience of unloading and transporting ash should be considered. 4.1.4 The design of the dust removal air duct should comply with the following provisions: a. The air duct should be laid openly. When it must be laid underground, the air duct should be placed in the trench. Only when the trench is used to reduce dust, can an additional air duct be omitted, but measures should be taken to clean the accumulated dust. b. The wind speed in the air duct should prevent the transported dust from being deposited. The vertical air duct should be 14-20m/s, and the horizontal air duct should be 16-25m/s.
Heating.
When the humidity of the dusty gas in the air duct is high, it should not be laid outdoors or passed through a room without heating. Otherwise, the air duct should be insulated or the air should be kept warm. To prevent blockage, the diameter of the air duct should not be less than the following values: 100mm for discharging fine dust
100mm for discharging coarse dust,
130mm for discharging coarse particles.
e. The dust removal air duct should be equipped with a cleaning hole.
4.2 Selection of ventilation and dust removal equipment
4.2.1 Fan
4.2.1.1 The dust removal system should use a centrifugal fan. The fan should be installed after the dust collector, but it can also be installed before the dust collector when the dust hardness is small, the concentration is low, and the particle size is fine. The fan before the dust collector should use a dust exhaust fan, and the fan after the dust collector can use an ordinary type. In two-stage dust removal, the fan can be installed after the first-stage dust collector. 4.2.1.2 Noise reduction measures should be taken when the fan noise exceeds the standard. 4.2.2 Dust removal equipment
4.2.2.1 The dust removal equipment should be reasonably selected based on national emission standards, the initial concentration, dispersion, density, operating resistivity, hydrophilicity, viscosity, toxicity, explosiveness, and physical and chemical properties of the gas such as temperature, humidity, and chemical composition, as well as equipment investment, occupied space, operating costs, maintenance and operation installation location, etc. 4.2.2.2 Bag dust collectors should be used for sand falling machines, granular dry material conveying equipment, crushing equipment, vibrating screens, grinding machines, etc. 4.2.2.3 Cyclone dust collectors can be used for grinding machines. Dispersed grinding machines should use bag dust removal units. 4.2.2.4 For equipment where materials can be directly returned to people, such as unpackers, silos, belt conveyor transfer points, sand mixers, etc., it is advisable to use bag dust removal units directly installed on the equipment.
GB 895988
4.2.2.5 For drum screens, multi-angle screens, cooling elevators, cleaning drums, sandblasting rooms, shot blasting rooms, and shot blasting rooms, it is advisable to use two-stage dust removal. However, when cleaning drums or shot blasting rooms, cleaning resin sand castings or castings that have been cleaned by hydraulic or water blasting, one-stage dust removal can be used. 4.2.2.6 When using dry dust collectors, when the gas humidity is high and condensation may occur, it should be insulated or heated, or a wet dust collector should be used. 4.2.2.7 In cold areas, wet dust collectors should not be arranged outdoors, otherwise insulation or heating measures should be taken. For bag dust collectors, when the gas temperature exceeds 130℃, high temperature resistant filter materials should be used. When the gas humidity is high, it is advisable to use 4.2.2.8 Hua
smooth filter materials.
4.3 Prevention and control of secondary pollution
4.3.1 Dry dust collector
4.3.1.1 The ash discharge valve of the dry dust collector should be well sealed, and the ash should be discharged in a closed container. 4.3.1.2 The dry ash discharged from the dust collector should be transported and disposed of in time, and measures such as closed transportation, wetting, granulation, and molding should be taken. The dry ash should be properly disposed of.
4.8.2 Wet dust collector
The wastewater discharged from the wet dust collector into the urban sewer and river should meet the discharge standards. 4.3.2.1
4.3.2.2 The sludge in the wastewater of the wet dust collector should be dehydrated and solidified. Sludge should be properly disposed of and should not be allowed to dry naturally and generate secondary dust.
4.4 Maintenance
4.4.1 Fan
4.4.1.1 The air volume, air pressure and motor input power should be tested at least once a year to check whether they meet the original design requirements. If not, they should be repaired and adjusted.
4.4.1.2 The fan should always be in good working condition, run smoothly, the shell should not be damaged, the impeller should be intact, there should be no dust or water accumulation in the machine, and the motor should work normally. Faults should be eliminated in time. 4.4.2 Dust removal equipment
4.4.2.1 The dust accumulation height in the ash hopper of the dry dust collector should not exceed 2/3 of the height of the ash hopper. 4.4.2.2 The outer shell of the dust collector should not be damaged. 4.4.2.3 The water level of the wet dust collector should be checked frequently and the interior should be cleaned regularly to meet the operating requirements. 4.4.3 Pipeline system
4.4.3.1 The air volume of each section of the pipeline should be measured at least once a year to check whether it meets the original design requirements. If not, it should be repaired and adjusted.
The pipeline should be cleaned 1 to 3 times a year according to the dust accumulation. 4.4.3.2
4.4.3.3 Check the sealing of the pipeline frequently. There should be no damage and the air leakage rate should not exceed 15%. 4.4.4 Exhaust hood
4.4.4.1 The installed exhaust hood should not be dismantled or discarded at will. If it is damaged, it should be repaired in time. 4.4.4.2 When the exhaust hood does not meet the dust prevention requirements, the cause should be checked and the fault should be eliminated in time. If the effect is not good, the hood structure should be modified. 4.4.4.3 In order to prevent the exhaust hood from being damaged, a protective enclosure can be added if necessary. 4.4.5 Establish a maintenance system
4.4.5.1 A practical maintenance system should be formulated according to the factory's organizational structure and personnel situation. 4.4.5.2 A maintenance file should be established for each ventilation and dust removal equipment and each system. 5 Management and supervision of dust prevention work
5.1 Management
5.1.1 Ventilation and dust removal equipment should be listed as fixed assets. 5.1.2 A management and professional maintenance organization should be established according to the number and complexity of ventilation and dust removal system equipment. The number of people can be considered as 2% to 3% of the dust-exposed personnel.
5.1.3 Necessary rules and regulations should be formulated: dust prevention work responsibility system, duty personnel code, operating procedures, operation records, fault reports, 188
GB8959-88
planned pre-repair, establishment of ventilation and dust removal system technical files and dust prevention work reward and punishment system, etc. All dust prevention work should be managed by a dedicated person and implemented conscientiously.
5.1.4 Implement the responsibility system for personnel at all levels of dust prevention equipment. Personnel should be designated to operate the ventilation and dust removal system of production equipment. 5.1.5 A cleaning system for the entire workshop should be established. Workers at each production post or a dedicated person shall be responsible for each piece of equipment and area. 5.1.6 A regular health check system for workers exposed to dust should be established. 5.2 Monitoring and Supervision
5.2.1 Each factory should be equipped with necessary dust testing instruments and corresponding testers. 5.2.2 The dust concentration in the working area of each section and the air volume, air pressure, dust removal efficiency, dust emission concentration, etc. of each ventilation and dust removal system should be measured at least once a year and recorded in the technical files. When it is found that it does not meet the hygiene standards or emission standards, the reasons should be checked and measures should be taken to solve it. 5.2.3 The ventilation and dust removal system should be put into operation at the same time as the production equipment, and its utilization rate should reach more than 90%. 5.2.4 There should be a dedicated person to supervise and inspect the operation, planned pre-repair and spare parts of the ventilation and dust removal equipment, and problems found should be solved according to the responsibility system.
5.3 Personnel training
5.3.1 All personnel exposed to dust and leaders in charge of dust prevention work should receive dust prevention safety education and undergo necessary assessments. 5.3.2 Personnel who operate, maintain, monitor and supervise ventilation and dust removal equipment must receive professional training and obtain qualifications before they can undertake the corresponding work.
GB 8959---88
Name and specification of process equipment
Cupola
Melt rate, t/h
Electric steelmaking furnace
Electric steelmaking furnace
Nominal capacity, t
Electric steelmaking furnace
Nominal capacity, t
Electric steelmaking furnace
Coke screen
Ferroalloy crusher
Charge port size, mm
900×580
2100×800
2500×1000
2600 ×1100
2800×1300
3000×1560
3000×1600
Maximum charge, t
Maximum charge, t
Volume, m3
Foundry workshop process
(reference
Exhaust hood type
Exhaust at the lower part of the feeding port
Upper split umbrella cover
Clamp-type exhaust hood
Furnace cover
Exhaust in the furnace
Enclosed chamber
Local enclosed hood at the loading and unloading port1 The air volume of each section of the pipeline should be measured at least once a year to check whether it meets the original design requirements. If not, it should be repaired and adjusted.
According to the dust accumulation in the pipeline, it should be cleaned 1 to 3 times a year. 4.4.3.2
4.4.3.3 Check the sealing of the pipeline frequently, and there should be no damage. The air leakage rate should not exceed 15%. 4.4.4 Exhaust hood
4.4.4.1 The installed exhaust hood shall not be dismantled or discarded at will. If it is damaged, it should be repaired in time. 4.4.4.2 When the exhaust hood does not meet the dust prevention requirements, the cause should be checked and the fault should be eliminated in time. If the effect is not good, the hood structure should be modified. 4.4.4.3 In order to prevent the exhaust hood from being damaged, a protective enclosure can be added if necessary. 4.4.5 Establish a maintenance system
4.4.5.1 A practical maintenance system should be formulated according to the factory's organizational structure and personnel situation. 4.4.5.2 A maintenance file for each ventilation and dust removal equipment and each system should be established. 5 Management and supervision of dust prevention work
5.1 Management
5.1.1 Ventilation and dust removal equipment should be listed as fixed assets. 5.1.2 A management and professional maintenance organization should be established according to the number and complexity of ventilation and dust removal system equipment, and its number can be considered as 2% to 3% of the dust-exposed personnel.
5.1.3 Necessary rules and regulations should be formulated: dust prevention work responsibility system, duty personnel code, operating procedures, operation records, fault reports, 188
GB8959—88
planned pre-repair, establishment of ventilation and dust removal system technical files and dust prevention work reward and punishment system. All dust prevention work should be managed by a dedicated person and implemented conscientiously.
5.1.4 Implement the responsibility system of personnel at all levels of dust prevention equipment. The ventilation and dust removal system of production equipment should be operated by designated personnel. 5.1.5 A cleaning system for the entire workshop should be established. Workers at each production post or a dedicated person shall be responsible for each piece of equipment and area. 5.1.6 A regular health check-up system for workers exposed to dust should be established. 5.2 Monitoring and Supervision
5.2.1 Each factory should be equipped with necessary dust testing instruments and corresponding testing personnel. 5.2.2 The dust concentration in the working area of each section and the air volume, air pressure, dust removal efficiency, dust emission concentration, etc. of each ventilation and dust removal system should be measured at least once a year and recorded in the technical files. When it is found that the hygiene standards or emission standards are not met, the reasons should be checked and measures should be taken to solve them. 5.2.3 The ventilation and dust removal system should be put into operation at the same time as the production equipment, and its utilization rate should be above 90%. 5.2.4 A dedicated person should supervise and inspect the operation, planned pre-repair and spare parts of the ventilation and dust removal equipment, and any problems found should be solved according to the responsibility system.
5.3 Personnel training
5.3.1 All personnel exposed to dust and leaders in charge of dust prevention work should receive dust prevention safety education and undergo necessary assessments. 5.3.2 Personnel who operate, maintain, monitor and supervise ventilation and dust removal equipment must receive professional training and obtain qualifications before they can undertake the corresponding work.
GB 8959---88
Name and specification of process equipment
Cupola
Melt rate, t/hbzxZ.net
Electric steelmaking furnace
Electric steelmaking furnace
Nominal capacity, t
Electric steelmaking furnace
Nominal capacity, t
Electric steelmaking furnace
Coke screen
Ferroalloy crusher
Charge port size, mm
900×580
2100×800
2500×1000
2600 ×1100
2800×1300
3000×1560
3000×1600
Maximum charge, t
Maximum charge, t
Volume, m3
Foundry workshop process
(reference
Exhaust hood type
Exhaust at the lower part of the feeding port
Upper split umbrella cover
Clamp-type exhaust hood
Furnace cover
Exhaust in the furnace
Enclosed chamber
Local enclosed hood at the loading and unloading port1 The air volume of each section of the pipeline should be measured at least once a year to check whether it meets the original design requirements. If not, it should be repaired and adjusted.
According to the dust accumulation in the pipeline, it should be cleaned 1 to 3 times a year. 4.4.3.2
4.4.3.3 Check the sealing of the pipeline frequently, and there should be no damage. The air leakage rate should not exceed 15%. 4.4.4 Exhaust hood
4.4.4.1 The installed exhaust hood shall not be dismantled or discarded at will. If it is damaged, it should be repaired in time. 4.4.4.2 When the exhaust hood does not meet the dust prevention requirements, the cause should be checked and the fault should be eliminated in time. If the effect is not good, the hood structure should be modified. 4.4.4.3 In order to prevent the exhaust hood from being damaged, a protective enclosure can be added if necessary. 4.4.5 Establish a maintenance system
4.4.5.1 A practical maintenance system should be formulated according to the factory's organizational structure and personnel situation. 4.4.5.2 A maintenance file for each ventilation and dust removal equipment and each system should be established. 5 Management and supervision of dust prevention work
5.1 Management
5.1.1 Ventilation and dust removal equipment should be listed as fixed assets. 5.1.2 A management and professional maintenance organization should be established according to the number and complexity of ventilation and dust removal system equipment, and its number can be considered as 2% to 3% of the dust-exposed personnel.
5.1.3 Necessary rules and regulations should be formulated: dust prevention work responsibility system, duty personnel code, operating procedures, operation records, fault reports, 188
GB8959—88
planned pre-repair, establishment of ventilation and dust removal system technical files and dust prevention work reward and punishment system. All dust prevention work should be managed by a dedicated person and implemented conscientiously.
5.1.4 Implement the responsibility system of personnel at all levels of dust prevention equipment. The ventilation and dust removal system of production equipment should be operated by designated personnel. 5.1.5 A cleaning system for the entire workshop should be established. Workers at each production post or a dedicated person shall be responsible for each piece of equipment and area. 5.1.6 A regular health check-up system for workers exposed to dust should be established. 5.2 Monitoring and Supervision
5.2.1 Each factory should be equipped with necessary dust testing instruments and corresponding testing personnel. 5.2.2 The dust concentration in the working area of each section and the air volume, air pressure, dust removal efficiency, dust emission concentration, etc. of each ventilation and dust removal system should be measured at least once a year and recorded in the technical files. When it is found that the hygiene standards or emission standards are not met, the reasons should be checked and measures should be taken to solve them. 5.2.3 The ventilation and dust removal system should be put into operation at the same time as the production equipment, and its utilization rate should be above 90%. 5.2.4 A dedicated person should supervise and inspect the operation, planned pre-repair and spare parts of the ventilation and dust removal equipment, and any problems found should be solved according to the responsibility system.
5.3 Personnel training
5.3.1 All personnel exposed to dust and leaders in charge of dust prevention work should receive dust prevention safety education and undergo necessary assessments. 5.3.2 Personnel who operate, maintain, monitor and supervise ventilation and dust removal equipment must receive professional training and obtain qualifications before they can undertake the corresponding work.
GB 8959---88
Name and specification of process equipment
Cupola
Melt rate, t/h
Electric steelmaking furnace
Electric steelmaking furnace
Nominal capacity, t
Electric steelmaking furnace
Nominal capacity, t
Electric steelmaking furnace
Coke screen
Ferroalloy crusher
Charge port size, mm
900×580
2100×800
2500×1000
2600 ×1100
2800×1300
3000×1560
3000×1600
Maximum charge, t
Maximum charge, t
Volume, m3
Foundry workshop process
(reference
Exhaust hood type
Exhaust at the lower part of the feeding port
Upper split umbrella cover
Clamp-type exhaust hood
Furnace cover
Exhaust in the furnace
Enclosed chamber
Local enclosed hood at the loading and unloading port
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.