The mixing station is mainly used for concrete construction projects. The main purpose is to mix and mix concrete, also called concrete mixing station. HZS series commercial concrete mixing plant adopts internationally popular modular rapid assembly structure, high-performance imported or domestic mixing main engine, dual-machine dual-control computer control mode, anti-noise, anti-dust pollution, and environmental protection design. It is a new generation of cement concrete mixing equipment.
Table of contents
1 Venue introduction
2 categories
3 specifications
4 International Standards
5 national standards
6 control system
7 main components
8 commercial mixing station
9 Safety Precautions
10 Productivity
11 models
12 Referenced Standards
13 concrete mixing plant
14 Management methods
15 Common Faults
▪ Air supply failure
▪ Cylinder failure
▪ Reversing valve
▪ Auxiliary components
▪ Mechanical failure
16 Import and export
17 Environmental acceptance criteria
Introduction
Pinyin: jiao ban zhan
English: CONCRETE MIXING PLANT
The mixing station is mainly used for concrete engineering, the main purpose is to mix concrete, also called concrete mixing station.
The mixing station is composed of systems and structural components such as feeding, storage, batching, mixing, discharging, and control, and is a complete set of equipment for producing concrete.
Classification
The mixing station can be divided into single-machine station and double-machine station. As the name suggests, a single-machine station means that each mixing station has one mixing mainframe, a double-machine station has two mixing mainframes, a multi-station group means more than two mixing mainframes, and each mixing mainframe corresponds to a discharge port, so the multi-station group and the double-machine mixing station are more than twice the production capacity of the single-machine mixing station. / hour four-unit mixing station.
Specification
The size of the mixing station is named according to its theoretical production per hour. The commonly used specifications in my country are: HZS25, HZS35, HZS45, HZS50, HZS60, HZS75, HZS90, HZS120, HZS150, HZS180, HZS240, etc. For example: HZS25 refers to a mixing station with a production capacity of 25 cubic meters per hour, and the main machine is a twin-shaft forced mixer. If the host uses a single horizontal shaft, the model is HZD25.
International standard
Name: ISO19720-1 "Building Construction Machinery and Equipment Concrete and Mortar Preparation Machinery and Equipment"
Drafting unit: Zoomlion [2]
Content: This international standard regulates the definition and classification of concrete and mortar preparation machinery and equipment (including concrete mixing station, concrete batching station, dry mixing station) and the definition of each main component, and also specifies the commercial specifications of related equipment in detail. This standard is the primary basic part of the international standard system for concrete and mortar preparation machinery and equipment, and it also lays a good and solid foundation for the subsequent standard formulation of such products.
Chinese national standard
Name: GB/T 10171-2016 "Building Construction Machinery and Equipment Concrete Mixing Station (Building)"
Drafting unit: Zhonglian
Main components
1. Aggregate supply system: aggregate hopper, aggregate weighing hopper, flat belt conveyor, inclined belt conveyor.
2. Stirring and mixing system: the main engine is a twin-shaft forced mixer or a vertical planetary reducer.
3. Powder supply system: powder bin, screw conveyor, cement weighing hopper.
4. Automatic water supply system: water tank, water pump, pipeline, water weighing hopper, admixture weighing hopper.
5. Electrical operating system: computer console, electric control cabinet, operating room.
6. Pneumatic control system: air compressor, air pipeline, solenoid valve, cylinder.
Commercial mixing plant
The commercial concrete mixing plant is to send the mixed concrete to the construction unit through a special concrete mixer truck. The models are mostly C20 (concrete for cushions), C30 (concrete for floors or walls), C35 (concrete for ring beams) and C50 (high-grade concrete for overpasses or viaducts). It realizes multiple combinations and feeding methods, can produce dry hard, semi-dry hard, plastic and various proportion concrete, and realizes the stone-wrapped mixing process, which greatly improves the quality of concrete.
Safety precaution
1. During the installation process, it is strictly forbidden to tilt the warehouse body and deform the outriggers.
2. The bottom of the outrigger is firmly welded to the foundation embedded parts.
3. Do a good job of wind and lightning protection.
4. It is strictly forbidden to hit the outriggers and the warehouse body strongly.
5. Regularly check the cement adhesion of the dust collector bag and clean it in time.
6. The foundation must be firm and conform to the architectural design specifications.
7. Once the cloth bag is blocked, the pressure in the warehouse exceeds the safety pressure of the pressure safety valve on the top of the warehouse, and the pressure safety valve can be opened to release the pressure in the warehouse to prevent the explosion accident.
8. When the cement silo (cement tank) is working, it must be erected by a special crane, and then placed on the prefabricated concrete foundation, and the verticality of the cement silo (cement tank) to the horizontal plane after it is erected is checked, and then its bottom is welded firmly with the foundation embedded parts.
Productivity
Under the specified test conditions, the concrete batching plant (floor) produces the amount of concrete per hour (in the volume after tamping). The test conditions refer to: a, the concrete materials are fully supplied, the finished concrete is discharged in time, and the concrete mixing station (building) operates continuously; b, the concrete mix ratio remains unchanged, the aggregate gradation, cement type and label, concrete label, slump and water consumption are all in accordance with the provisions of GB4477; c, the amount of concrete mixed in each cycle should be calculated based on the nominal capacity of the concrete mixing unit; d, no admixtures and additives are added, and no dry mixing is performed.
Model
It consists of the group code of the concrete mixing plant (building), the number of installed units, the type code of the mixer, the main parameters and the variant or update code, etc. Among them, the group code HZ is a concrete mixing station, HL is a concrete mixing building; the number of installed units is standard in Arabic numerals, and a single machine can be omitted; the type code of the mixer is S for double-horizontal shaft type, D for single-horizontal shaft type, T for planetary type, W for whirlpool type, F for conical inclined discharge type, Z for conical reverse discharge type; the main parameter code is productivity, and the unit is m3/h; the change or update code is represented by A, B, C....
Concrete mixing plant
The concrete mixing plant (building) is composed of systems and structural components such as feeding, storage, batching, discharging, and control. Concentrated mixing of cement concrete with concrete mixing plant (floor) has many advantages:
(1) The centralized mixing of cement concrete facilitates strict control of the concrete mix ratio, ensures the quality of the concrete, and fundamentally changes the inaccurate situation of on-site dispersion and mixing ingredients;
(2) The centralized mixing of cement concrete is conducive to the adoption of automation technology, which can greatly improve labor productivity, save labor and reduce costs;
(3) The use of centralized mixing does not require installation of mixing equipment, stacking of sand and gravel, and storage of cement on the construction site, thereby saving space and avoiding waste of raw materials.
Concrete mixer host can be divided into self-falling type and forced type according to the type. The capacity of the self-falling mixing drum can be made very large, which is suitable for mixing large aggregates.
The forced mixer is divided into vertical shaft and horizontal shaft. The concrete quality of the forced mixer is good, suitable for mixing low slump and dry hard concrete.
Management method
The mixing plant is the core of the project. The equipment status, maintenance, personnel composition, division of labor and cooperation of the mixing plant will directly affect the reliability of production efficiency and project quality. Therefore, formulating effective management measures for mixing plants is the key to ensuring project quality, improving work efficiency, and achieving project quality goals.
Common malfunctions
The air circuit system is the executive device for the action of the concrete mixing plant. Its function is to open and close each aggregate bin, mixer discharge door, and cement scale discharge door in time according to the instructions issued by the industrial computer, break the arch of the cement in the cement bin, blow and mix the additives, ensure the accurate measurement of various aggregates, cement, and additives, and complete the loading of finished materials. Only by using and maintaining the system correctly can the high efficiency and good economy of the whole machine production be guaranteed.
The common faults mainly include the following five types:
Air supply failure
Common failures of air sources occur in air compressors, pressure reducing valves, pipelines, compressed air processing components, etc.
(1) The common faults of the air compressor are the damage of the check valve, the serious wear of the piston ring, the damage of the intake valve plate and the clogging of the air filter.
After the air compressor automatically stops for more than ten seconds, turn off the power supply and turn the large tape wheel by hand. If it can be rotated easily for a circle, it means that the check valve is not damaged, otherwise it is damaged; it can also be judged according to the exhaust condition of the exhaust port under the automatic pressure switch. When the pressure of the air compressor rises slowly accompanied by oil leakage, it indicates that the piston ring of the air compressor has been severely worn and should be replaced in time. When the intake valve is damaged or the air filter is blocked, the pressure of the air compressor will rise slowly (but there is no oil blowing). Put your palm on the air inlet of the air filter. If there is hot air pushing out, it means that the air inlet valve is damaged and needs to be replaced; if the suction is weak, it is generally caused by the air filter being dirty, and the filter should be cleaned or replaced.
(2) The pressure reducing valve is faulty. If the pressure is not adjusted high, it is often because the pressure regulating spring is broken or the diaphragm is broken and must be replaced; if the pressure rises slowly, it is usually because the filter is clogged and should be removed for cleaning.
(3) Pipeline failure. When the joint leaks or the hose is broken, the location of the air leak can be judged by the sound. If the condensed water accumulates in the pipeline and it is easy to freeze and block the air path, it should be removed in time.
(4) Compressed air processing component failure. The filter element of the oil-water separator is clogged and damaged, and the moving parts of the blowdown valve are not flexible. Clean the filter element frequently to remove oil and other impurities in the drain valve. The oil mist device does not drip oil, moisture is deposited on the bottom of the oil cup, and the sealing ring of the oil cup mouth is damaged. It should be checked whether the air flow at the air inlet is lower than the fogging flow, whether there is air leakage, whether the oil volume adjustment needle valve is blocked, etc.
Cylinder failure
(1) Internal and external leakage of the cylinder is generally caused by eccentric installation of the piston rod, insufficient supply of lubricating oil, wear or damage of the seal ring and seal ring, impurities in the cylinder and scars on the piston rod. The center position of the piston rod should be readjusted, the reliability of the lubricator should be checked frequently, and the impurities in the cylinder should be removed in time; when there is a scratch on the piston rod, a new one should be replaced.
(2) Insufficient output force of the cylinder and unstable movement are generally caused by the piston or piston rod being stuck, poor lubrication, insufficient air supply, or condensed water and impurities in the cylinder. The center position of the piston rod should be adjusted; check the reliability of the lubricator; whether the gas supply line is blocked, and the condensed water and impurities in the cylinder should be removed in time.
(3) The cushioning effect of the cylinder is poor, generally due to the wear of the buffer seal ring or the damage of the adjustment screw, the seal ring and the adjustment screw should be replaced.
(4) The piston rod and cylinder head are damaged, generally because the piston rod is installed eccentrically or the buffer mechanism does not work. The center position of the piston rod should be adjusted in time, and the buffer seal ring or adjusting screw should be replaced if necessary.
Reversing valve
(1) Cannot change direction or change direction slowly. First check whether the lubricator is working normally; whether the degree of lubricating oil is appropriate. If necessary, replace the lubricating oil, clean the sliding part of the reversing valve or replace the spring and reversing valve.
(2) The sealing ring of the valve core is worn, the valve core and seat are damaged, the gas in the valve leaks, the movement is slow or the direction cannot be changed normally, the sealing ring, valve core and valve seat should be replaced, and a new reversing valve should be replaced if necessary.
(3) The intake and exhaust holes of the pilot solenoid valve are blocked by sludge and other debris, the seal is not tight, the movable valve core is stuck, and circuit failures can cause the reversing valve to fail to reversing normally. Impurities such as oil sludge on the pilot solenoid valve and movable spool should be cleaned in time. Before checking the circuit fault, turn the manual knob of the reversing valve a few times to see if the reversing valve can reversing normally under the rated air pressure. If it can reversing normally, the circuit is faulty. When checking, use a meter to measure the voltage of the electromagnetic coil to see if it has reached the rated voltage. If the voltage is too low, you should further check the power supply in the control circuit and the related travel switch circuit. If the reversing valve cannot be reversing normally under the rated voltage, check whether the connector (plug) of the electromagnetic coil is loose or not in good contact. The method is to unplug the plug and measure the resistance value of the coil (generally it should be between several hundred to several thousand ohms). If the resistance value is too large or too small, it means that the electromagnetic coil is damaged and should be replaced.
Auxiliary components
(1) The adjustment amount of the adjusting needle of the lubricator is too small, the oil circuit is blocked, and the pipeline leaks, etc., which will prevent the liquid oil droplets from being atomized. The blockage and air leakage should be dealt with in time, and the dripping oil volume should be adjusted to about 5 drops/min. During normal use, the oil level in the oil cup should be kept within the upper and lower limits. The moisture deposited at the bottom of the oil cup should be removed in time.
(2) Sometimes the oil and water in the automatic sewage discharger cannot be automatically removed, so it should be removed for inspection and cleaning.
(3) When the muffler installed on the reversing valve is too dirty or blocked, it will also affect the sensitivity of the reversing valve, so the muffler should be cleaned frequently.
mechanical failure
The material door shaft driven by the cylinder is often stuck at the discharge port of the powder metering hopper; the flap disc valve driven by the rack-type cylinder is stuck, making it unable to close or open. Therefore, the powder agglomeration on the inner wall of the flap disc valve should be removed frequently.
Import and export
The concrete version weighbridge software is mainly a measurement management software for concrete mixing station enterprises in the process of raw material procurement, finished concrete sales and asphalt mixture sales. Including: daily accumulation, current month accumulation, fast conversion of tons and square meters, and convenient functions of instant statistics. It can print the incoming weight list, the sales weight list, and two separate serial numbers. The sales can print the concrete weight list with only the square quantity, and can also print the asphalt factory weight list with the tonnage at the same time.
Environmental acceptance criteria
Environmental protection is a matter of great concern in today's economic development. Every item of environmental protection must be checked when the concrete mixing plant is completed and accepted, which is also the basic requirement for building a civilized mixing plant and green concrete production. In our acceptance, the environmental protection standard of the mixing plant is mainly to effectively control dust, waste water, noise, and solid waste. So as to realize the real green production of concrete.
Dust Control:
The places where dust is likely to be generated in the concrete mixing plant are mainly the feeding port of the mixing building, the material yard and the powder tank. The mixing building of the equipment selected to prevent dust from spilling is closed mixing. In order to further eliminate dust during production, a movable color steel plate is added as a dust surface, and a space with a closed dust outlet is used to control the generated dust in a closed space for disposal. Two outer symmetrical water mist injection pipes are added at the cement feeding port to suppress the dust and prevent the dust from spreading from the source. In the stockyard, spraying devices are mainly installed on the top. When the dust in the stockyard is large, the spray can be controlled manually or automatically to suppress the dust. The mouth of the stockyard can also be equipped with an automatic high-pressure water curtain. Prevent dust spillage.
Wastewater treatment:
Drainage ditches are installed in the concrete mixing station, and a three-stage sedimentation tank is installed at the end of the drainage ditch, and a solid-liquid separation device and a filter press device are equipped to separate the waste from the well sewage for reuse. The water after precipitation is recycled, so that the wastewater in the entire production area can be recycled after being fully treated, that is, it can reach the environmental discharge standard. Realize zero discharge of sewage.
Noise Control:
The noise in the concrete mixing plant mainly comes from the mixing main equipment, the air compressor and the vehicles in the station. The noise of the equipment itself can be installed in a closed concrete structure, and the maintenance and overhaul are strengthened during use, which not only prolongs the service life of the equipment, but also reduces noise pollution. For the noise generated by vehicles, if a station is built in a residential area, it is necessary to set up partition walls and partition belts according to the actual situation.
Solid waste disposal:
The solid waste in the concrete mixing plant is mainly solid waste and domestic garbage produced by cleaning and sand separation. The garbage pool built in the station is uniformly stacked, managed and disposed of uniformly. Production waste can be mixed into concrete production according to the actual situation, and domestic waste should be collected and transported by municipal garbage trucks for unified treatment.
