Concrete pump was first invented by Europe. It was introduced into China in the 80s of the previous world. Therefore, the development of concrete pump in China has only been more than 30 years. Although the development history is not long, the development speed of concrete pump in China is The world is eye-catching. Below I introduce the basic situation of China's concrete pump:
First, the classification of concrete pump:
1. Classification method of concrete pump: There are piston type and extrusion type according to the driving method of concrete pump. Most of them are hydraulic piston type. The hydraulic piston pump presses the piston different media, but can be divided into pneumatic and hydraulic type, most of the hydraulic type. According to whether or not the pump can be moved, there are fixed concrete pump, towed concrete pump, and truck-mounted concrete pump. Among them, there are many applications of towed concrete pump and truck-mounted concrete pump. Divided by the form of reversing valve: There are disc valve, gate valve, S valve, C valve T valve, etc. Currently used more double-cylinder work S valve and valve gate valve.
2. The difference between the gate valve and the S-shaped pipe valve: The main advantage of the concrete valve of the gate valve is that the requirements for the aggregate are not strict, and 2-4 aggregates are used; the suction is good, and the requirements for the concrete are not like the S-shape. The tube-valve concrete pump is as high as it can pump low slump concrete. However, the sealing of the gate valve is limited by the structure, the sealing pressure is low, the outlet pressure is low, generally only 8mpa or less, and it is not suitable for long-distance pumping. When using a gate valve to vertically transport concrete, it is also required to install a horizontal duct in front of the vertical duct, which is 1/2 the length of the vertical duct. Because the gate is very sensitive to the gravity generated by the concrete in the vertical direction, it will reduce the suction of the pump. This resistance will also reduce the height of the concrete.
S-shaped pipe valve's main advantages: its good sealing performance, high outlet pressure, generally more than 13mpa, the highest can reach 40 mpa, so the S valve pump than the same size of the gate valve pump delivery height, distance is more far. The hopper is designed with hydrodynamic principles to minimize the flow resistance of the concrete. The S valve is currently the most widely used concrete distribution valve. Its main features are simple structure, smooth flow channel, small concrete flow resistance, good sealing performance, high pumping pressure, and is widely used in various engineering constructions.
Second, the characteristics of concrete pump:
1. The concrete pump has the following characteristics: 1Conveying and pouring of concrete is continuous, construction efficiency is high, project progress is fast; 2 high degree of mechanization, reducing labor; 3 pumping process on the concrete quality requirements are more stringent, also It can be said that the pumping is a test of the concrete quality, and because the pumping is continuous, the concrete is not easy to separate in the pumping process, the concrete slump loss is not large, so it is easy to ensure the quality of the project; 4 on the construction surface With adaptability and wide operation range, the concrete conveying pipeline can be laid to other hard-to-reach places, and the concrete can be filled and poured into place under certain pressure. The pump can also be used in series to increase the conveying distance and height, satisfying Various construction requirements; 5 Under normal pumping conditions, concrete transport in pipelines will not pollute the environment and comply with environmental protection requirements.
III. 1. Theoretical Displacement of Concrete Transport: Theoretical Value of Pumped Concrete Volume per Hour for Concrete Pumps (m3/h)
Theoretical displacement Q=V×n×t
V--theoretical volume of each stroke of concrete pump (m3/times)
n--The number of rated working strokes per hour of the concrete pump (times/h)
T—the number of commutations per minute, usually about 20 times
2. The actual displacement of the concrete pump. The actual volume of concrete (m3/h) delivered by concrete pump per hour.
Actual delivery Qs=Q×Kv
Volumetric efficiency Kv=0.7-0.9
3. Concrete pump outlet pressure: concrete pump pressure is the concrete pressure (MPa) at the outlet of the pump. At present, there are 8mpa, 13mpa, 16mpa, 18mpa, 21mpa, etc. .
Fourth, the basic structure of the concrete pump The concrete pump is mainly composed of pumping system, hydraulic system, electronic control system, lubrication system and cooling system.
1. Pumping system: This system is the executing mechanism of the concrete pump. It consists of five systems: hopper, S valve, conveying cylinder, and main tank of the tank. It is commonly called five pieces and is used to continuously convey the concrete mixture to the pouring site. The transmission pump pumping conditions are generally divided into high pressure low displacement and low pressure large displacement two pressure modes. The user can reasonably select the concrete transportation height (or distance) and displacement requirements according to the project. The high and low pressure switching methods include: replacing the hose, valve block position rotation and manual reversing valve, automatic high and low pressure switching technology; some of the new technology also uses the automatic retraction piston technology, the concrete piston can be returned to the water tank by itself. Check the concrete seal for wear, clean and maintain it, and extend the service life of the piston.
2. Hydraulic system: separate and closed type hydraulic system. Open type system has the advantages of low hydraulic oil temperature and high cleanliness. Closed system has the advantage of compact structure. Most of domestic products adopt open system. At present, there are two kinds of hydraulic control methods on the market, namely, full hydraulic commutation and electro-hydraulic commutation. The 31 is full hydraulic commutation, and Zhonglian uses electrohydraulic commutation.
3. Electronic control system: The main circuit generally adopts star-delta step-down start-up and soft-start, and the secondary circuit is generally controlled by PLC. Some products are equipped with text display and touch buttons, and have a good man-machine interface. Easy to diagnose and repair. The electronic control system controls the on-off of the solenoid valve through the programmable logic controller PLC, thereby realizing the alternating reciprocating motion of the concrete transfer pump.
4. The lubrication system cap consists of a grease pump and a distributor that lubricates various frictional parts. Lithium base grease No. 00 is used in summer, and lithium base grease No. 000 is used in winter.
5. The cooling system is divided into water cooling and air cooling. The water cooling method is used to string a water cooler in the oil return pipeline of the hydraulic system. When the concrete pump is working, it needs to be cooled by tap water and consume water; the air cooling method is in the hydraulic system. A wind radiator in the return line is more commonly used.
First, the classification of concrete pump:
1. Classification method of concrete pump: There are piston type and extrusion type according to the driving method of concrete pump. Most of them are hydraulic piston type. The hydraulic piston pump presses the piston different media, but can be divided into pneumatic and hydraulic type, most of the hydraulic type. According to whether or not the pump can be moved, there are fixed concrete pump, towed concrete pump, and truck-mounted concrete pump. Among them, there are many applications of towed concrete pump and truck-mounted concrete pump. Divided by the form of reversing valve: There are disc valve, gate valve, S valve, C valve T valve, etc. Currently used more double-cylinder work S valve and valve gate valve.
2. The difference between the gate valve and the S-shaped pipe valve: The main advantage of the concrete valve of the gate valve is that the requirements for the aggregate are not strict, and 2-4 aggregates are used; the suction is good, and the requirements for the concrete are not like the S-shape. The tube-valve concrete pump is as high as it can pump low slump concrete. However, the sealing of the gate valve is limited by the structure, the sealing pressure is low, the outlet pressure is low, generally only 8mpa or less, and it is not suitable for long-distance pumping. When using a gate valve to vertically transport concrete, it is also required to install a horizontal duct in front of the vertical duct, which is 1/2 the length of the vertical duct. Because the gate is very sensitive to the gravity generated by the concrete in the vertical direction, it will reduce the suction of the pump. This resistance will also reduce the height of the concrete.
S-shaped pipe valve's main advantages: its good sealing performance, high outlet pressure, generally more than 13mpa, the highest can reach 40 mpa, so the S valve pump than the same size of the gate valve pump delivery height, distance is more far. The hopper is designed with hydrodynamic principles to minimize the flow resistance of the concrete. The S valve is currently the most widely used concrete distribution valve. Its main features are simple structure, smooth flow channel, small concrete flow resistance, good sealing performance, high pumping pressure, and is widely used in various engineering constructions.
Second, the characteristics of concrete pump:
1. The concrete pump has the following characteristics: 1Conveying and pouring of concrete is continuous, construction efficiency is high, project progress is fast; 2 high degree of mechanization, reducing labor; 3 pumping process on the concrete quality requirements are more stringent, also It can be said that the pumping is a test of the concrete quality, and because the pumping is continuous, the concrete is not easy to separate in the pumping process, the concrete slump loss is not large, so it is easy to ensure the quality of the project; 4 on the construction surface With adaptability and wide operation range, the concrete conveying pipeline can be laid to other hard-to-reach places, and the concrete can be filled and poured into place under certain pressure. The pump can also be used in series to increase the conveying distance and height, satisfying Various construction requirements; 5 Under normal pumping conditions, concrete transport in pipelines will not pollute the environment and comply with environmental protection requirements.
III. 1. Theoretical Displacement of Concrete Transport: Theoretical Value of Pumped Concrete Volume per Hour for Concrete Pumps (m3/h)
Theoretical displacement Q=V×n×t
V--theoretical volume of each stroke of concrete pump (m3/times)
n--The number of rated working strokes per hour of the concrete pump (times/h)
T—the number of commutations per minute, usually about 20 times
2. The actual displacement of the concrete pump. The actual volume of concrete (m3/h) delivered by concrete pump per hour.
Actual delivery Qs=Q×Kv
Volumetric efficiency Kv=0.7-0.9
3. Concrete pump outlet pressure: concrete pump pressure is the concrete pressure (MPa) at the outlet of the pump. At present, there are 8mpa, 13mpa, 16mpa, 18mpa, 21mpa, etc. .
Fourth, the basic structure of the concrete pump The concrete pump is mainly composed of pumping system, hydraulic system, electronic control system, lubrication system and cooling system.
1. Pumping system: This system is the executing mechanism of the concrete pump. It consists of five systems: hopper, S valve, conveying cylinder, and main tank of the tank. It is commonly called five pieces and is used to continuously convey the concrete mixture to the pouring site. The transmission pump pumping conditions are generally divided into high pressure low displacement and low pressure large displacement two pressure modes. The user can reasonably select the concrete transportation height (or distance) and displacement requirements according to the project. The high and low pressure switching methods include: replacing the hose, valve block position rotation and manual reversing valve, automatic high and low pressure switching technology; some of the new technology also uses the automatic retraction piston technology, the concrete piston can be returned to the water tank by itself. Check the concrete seal for wear, clean and maintain it, and extend the service life of the piston.
2. Hydraulic system: separate and closed type hydraulic system. Open type system has the advantages of low hydraulic oil temperature and high cleanliness. Closed system has the advantage of compact structure. Most of domestic products adopt open system. At present, there are two kinds of hydraulic control methods on the market, namely, full hydraulic commutation and electro-hydraulic commutation. The 31 is full hydraulic commutation, and Zhonglian uses electrohydraulic commutation.
3. Electronic control system: The main circuit generally adopts star-delta step-down start-up and soft-start, and the secondary circuit is generally controlled by PLC. Some products are equipped with text display and touch buttons, and have a good man-machine interface. Easy to diagnose and repair. The electronic control system controls the on-off of the solenoid valve through the programmable logic controller PLC, thereby realizing the alternating reciprocating motion of the concrete transfer pump.
4. The lubrication system cap consists of a grease pump and a distributor that lubricates various frictional parts. Lithium base grease No. 00 is used in summer, and lithium base grease No. 000 is used in winter.
5. The cooling system is divided into water cooling and air cooling. The water cooling method is used to string a water cooler in the oil return pipeline of the hydraulic system. When the concrete pump is working, it needs to be cooled by tap water and consume water; the air cooling method is in the hydraulic system. A wind radiator in the return line is more commonly used.
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