(1) Principles of pipe and groove selection
The selection of slurry pipelines and tank lines should generally consider the following principles:
(1) does not occupy or occupy less farmland;
(2) Avoid crossing urban and residential areas;
(3) Try to use self-flow or shorten the length of the line;
(4) Avoid passing through unfavorable geological locations or flooded areas;
(5) To facilitate construction and maintenance.
(2) Requirements for laying pipes and tanks
A. There are three main forms of laying, embedding and concealing. Among them, the most widely used ones are the ones that are used in the Ming Dynasty. The main advantage is that it is easy to inspect and repair, but it is vulnerable to temperature changes and external damage. At present, foreign long-distance slurry pipeline transportation is often used for burying. The advantage is that it can avoid the influence of temperature, external damage and land competition with agriculture, but it is necessary to have a self-checking device for maintenance troubles. It is concealed that the pipes and troughs are laid in the trenches or tunnels, and are generally used in areas with frequent traffic or restricted by terrain.
B Requirements for laying (1) At present, domestic slurry pressure conveying pipes are used in many equipments. Self-flow pipes and tanks are not used for equipment, but special protection measures are taken in areas with heavy traffic or severe wear and tear;
(2) The maximum laying slope of the pressure conveying pipeline should be determined according to the test. When there is no test data, it should be considered according to the factors such as pipe diameter, slurry characteristics and temperature, but the minimum slope should not be less than 2‰, and should be added in the cold area. Big;
(3) The turning angle of the self-flow pipe and the groove should be minimized, and the maximum corner should not be greater than 45°. If the curve is used, the radius of curvature should not be less than 5 times the groove width;
(4) Self-flow pipes and troughs with excessive elevation differences in terrain should consider segmental water fall;
(5) The elevation of the subgrade of the pipe and trough line should be 0.5 m above the highest flood level with a frequency of 2 to 5%. The net width between the pipes (tanks) should meet the needs of maintenance, the minimum should not be less than 0.4 meters, and the distance from the outer wall of the pipe (slot) to the side of the embankment should not be less than 0.3 meters. When there is a walkway outside the pipe (slot), it should be widened to 0.5 m;
(6) the tube, the cross should comply with the provisions of the relevant slot and the rail, road, river, etc. appear.
(3) Pipes, tank materials and ancillary facilities
A Material selection Pressure pipelines The most commonly used pipes in China are steel pipes and cast iron pipes. Polyethylene plastic pipes (PVC), which have been widely used abroad, are rarely used in China. Although the cast iron pipe is cheaper than the steel pipe, it can only be used for slurry transfer with a working pressure of less than 0.74 MPa (7.5 kg/cm 3 ), and the repair is also more troublesome than the steel pipe, and the wear resistance is also poor.
Self-flow pipes are made of steel, cast iron, reinforced concrete, etc., and individual mines use wood pipes. Most of the self-flowing troughs are masonry, concrete, reinforced concrete, etc., but individual or elevated troughs are made of wooden or steel troughs. [next]
B wear-resistant lining materials Although there are many varieties of wear-resistant pipes in the world, so far the domestic wear-resistant pipes are mainly cast stone products, cast stone products (including cast stone pipes, cast stone plates, cast stone pipe fittings) The wear resistance is generally 5 to 50 times higher than that of ordinary carbon steel. Moreover, it has corrosion resistance to acids and alkalis. However, due to its poor impact strength, it is not suitable for cast stone pipe pressure tube used, if you want to make use of the pressure tube, cast metal pipe must have for the outer tube. Due to the long-term failure to obtain recognized reliable data for some design parameters (such as head loss, compressive strength, etc.) of cast stone pipe, and the construction method is also complicated, it is difficult to guarantee the construction quality, so in the slurry conveying pipeline, especially far There are not many examples of conveyor pipes that are lined with cast stone. In recent years, some major domestic cast stone products manufacturers have done a lot of testing and research work in order to change this state. For example, the recently developed “pressure-resistant cast stone sandwich casing†greatly simplifies the construction procedure and ensures the installation quality. However, in general, there are still many problems in the cast stone pipe, such as short pipe section, heavy weight, complicated and complicated joints, incomplete design parameters, etc., which are urgent problems to be solved.
C slurry valve The slurry valve currently used in China can be divided into three types: cast iron valve and rubber-lined valve (including rubber valve, granular mud valve, etc.). The main driving power is manual, electric, hydraulic, and compressed air. Four kinds of power. Due to the poor wear resistance of cast iron valves, most of them have been replaced by other slurry valves. The appearance of rubber-lined valves (including hose valves) is only 20 years old, and its working life is generally several times to several tens of times higher than that of ordinary cast iron valves, so its price is high, and it is also popular with a large number of users. However, since the rubber-lined valve is not suitable for conveying slurry containing coarse, sharp, and hard-body particles, it cannot completely replace the function of the metal valve.
The particle mud valve was originally a new type of metal mud valve successfully developed by Shenyang Oil Pump Factory with the introduction of foreign technology. In May 1982, it began mass production through identification. In the past two years, other valve manufacturers in China have also come out with similar products. The main feature of the structure is that the steel gate plate with the same size as the pipe diameter is inserted into the valve body which can be automatically sealed on both sides. When the ram is fully open, the slurry flow resistance is only the frictional resistance of the pipe. In addition, there is no additional resistance due to the ram. Since the shutter is thin and the switching resistance is small, it is easy to switch. The gate seal consists of a seal and a water seal. The water seal layer keeps the seal from direct contact with the slurry, so the drive part of the upper part of the gate valve is not subject to any wear of the slurry. This type of valve is currently used by many factories and mines, but no more consistent opinions have been seen by users.
D Exhaust device and discharge valve are generally equipped with an exhaust device at the highest point of the upwardly bent pipe section of the low-concentration slurry pressure transmission line to exclude the air mixed in the pipeline during the pipeline transportation to ensure the normal operation of the pump and the pipeline. In the past, automatic exhaust valves and exhaust branch pipes were installed on the slurry pipes. However, the practice proved that the use effect was not good. Nowadays, ordinary gate valves are used instead, which has proved to be feasible.
Low-concentration slurry pressure pipes also need to consider the ore-mining measures in the event of an accident. When an accident occurs in the pipeline, it is necessary to discharge the slurry or flushing water of the low-concave pipe section. Generally, it is considered to install a discharge valve near the lowest point of the lower bend of the pipeline, but the selection of the position of the discharge valve should be related to the accidental ore deposit temporary pile. The location of the venue is considered.
The selection of slurry pipelines and tank lines should generally consider the following principles:
(1) does not occupy or occupy less farmland;
(2) Avoid crossing urban and residential areas;
(3) Try to use self-flow or shorten the length of the line;
(4) Avoid passing through unfavorable geological locations or flooded areas;
(5) To facilitate construction and maintenance.
(2) Requirements for laying pipes and tanks
A. There are three main forms of laying, embedding and concealing. Among them, the most widely used ones are the ones that are used in the Ming Dynasty. The main advantage is that it is easy to inspect and repair, but it is vulnerable to temperature changes and external damage. At present, foreign long-distance slurry pipeline transportation is often used for burying. The advantage is that it can avoid the influence of temperature, external damage and land competition with agriculture, but it is necessary to have a self-checking device for maintenance troubles. It is concealed that the pipes and troughs are laid in the trenches or tunnels, and are generally used in areas with frequent traffic or restricted by terrain.
B Requirements for laying (1) At present, domestic slurry pressure conveying pipes are used in many equipments. Self-flow pipes and tanks are not used for equipment, but special protection measures are taken in areas with heavy traffic or severe wear and tear;
(2) The maximum laying slope of the pressure conveying pipeline should be determined according to the test. When there is no test data, it should be considered according to the factors such as pipe diameter, slurry characteristics and temperature, but the minimum slope should not be less than 2‰, and should be added in the cold area. Big;
(3) The turning angle of the self-flow pipe and the groove should be minimized, and the maximum corner should not be greater than 45°. If the curve is used, the radius of curvature should not be less than 5 times the groove width;
(4) Self-flow pipes and troughs with excessive elevation differences in terrain should consider segmental water fall;
(5) The elevation of the subgrade of the pipe and trough line should be 0.5 m above the highest flood level with a frequency of 2 to 5%. The net width between the pipes (tanks) should meet the needs of maintenance, the minimum should not be less than 0.4 meters, and the distance from the outer wall of the pipe (slot) to the side of the embankment should not be less than 0.3 meters. When there is a walkway outside the pipe (slot), it should be widened to 0.5 m;
(6) the tube, the cross should comply with the provisions of the relevant slot and the rail, road, river, etc. appear.
(3) Pipes, tank materials and ancillary facilities
A Material selection Pressure pipelines The most commonly used pipes in China are steel pipes and cast iron pipes. Polyethylene plastic pipes (PVC), which have been widely used abroad, are rarely used in China. Although the cast iron pipe is cheaper than the steel pipe, it can only be used for slurry transfer with a working pressure of less than 0.74 MPa (7.5 kg/cm 3 ), and the repair is also more troublesome than the steel pipe, and the wear resistance is also poor.
Self-flow pipes are made of steel, cast iron, reinforced concrete, etc., and individual mines use wood pipes. Most of the self-flowing troughs are masonry, concrete, reinforced concrete, etc., but individual or elevated troughs are made of wooden or steel troughs. [next]
B wear-resistant lining materials Although there are many varieties of wear-resistant pipes in the world, so far the domestic wear-resistant pipes are mainly cast stone products, cast stone products (including cast stone pipes, cast stone plates, cast stone pipe fittings) The wear resistance is generally 5 to 50 times higher than that of ordinary carbon steel. Moreover, it has corrosion resistance to acids and alkalis. However, due to its poor impact strength, it is not suitable for cast stone pipe pressure tube used, if you want to make use of the pressure tube, cast metal pipe must have for the outer tube. Due to the long-term failure to obtain recognized reliable data for some design parameters (such as head loss, compressive strength, etc.) of cast stone pipe, and the construction method is also complicated, it is difficult to guarantee the construction quality, so in the slurry conveying pipeline, especially far There are not many examples of conveyor pipes that are lined with cast stone. In recent years, some major domestic cast stone products manufacturers have done a lot of testing and research work in order to change this state. For example, the recently developed “pressure-resistant cast stone sandwich casing†greatly simplifies the construction procedure and ensures the installation quality. However, in general, there are still many problems in the cast stone pipe, such as short pipe section, heavy weight, complicated and complicated joints, incomplete design parameters, etc., which are urgent problems to be solved.
C slurry valve The slurry valve currently used in China can be divided into three types: cast iron valve and rubber-lined valve (including rubber valve, granular mud valve, etc.). The main driving power is manual, electric, hydraulic, and compressed air. Four kinds of power. Due to the poor wear resistance of cast iron valves, most of them have been replaced by other slurry valves. The appearance of rubber-lined valves (including hose valves) is only 20 years old, and its working life is generally several times to several tens of times higher than that of ordinary cast iron valves, so its price is high, and it is also popular with a large number of users. However, since the rubber-lined valve is not suitable for conveying slurry containing coarse, sharp, and hard-body particles, it cannot completely replace the function of the metal valve.
The particle mud valve was originally a new type of metal mud valve successfully developed by Shenyang Oil Pump Factory with the introduction of foreign technology. In May 1982, it began mass production through identification. In the past two years, other valve manufacturers in China have also come out with similar products. The main feature of the structure is that the steel gate plate with the same size as the pipe diameter is inserted into the valve body which can be automatically sealed on both sides. When the ram is fully open, the slurry flow resistance is only the frictional resistance of the pipe. In addition, there is no additional resistance due to the ram. Since the shutter is thin and the switching resistance is small, it is easy to switch. The gate seal consists of a seal and a water seal. The water seal layer keeps the seal from direct contact with the slurry, so the drive part of the upper part of the gate valve is not subject to any wear of the slurry. This type of valve is currently used by many factories and mines, but no more consistent opinions have been seen by users.
D Exhaust device and discharge valve are generally equipped with an exhaust device at the highest point of the upwardly bent pipe section of the low-concentration slurry pressure transmission line to exclude the air mixed in the pipeline during the pipeline transportation to ensure the normal operation of the pump and the pipeline. In the past, automatic exhaust valves and exhaust branch pipes were installed on the slurry pipes. However, the practice proved that the use effect was not good. Nowadays, ordinary gate valves are used instead, which has proved to be feasible.
Low-concentration slurry pressure pipes also need to consider the ore-mining measures in the event of an accident. When an accident occurs in the pipeline, it is necessary to discharge the slurry or flushing water of the low-concave pipe section. Generally, it is considered to install a discharge valve near the lowest point of the lower bend of the pipeline, but the selection of the position of the discharge valve should be related to the accidental ore deposit temporary pile. The location of the venue is considered.
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