Stable cold material gradation and cold feed ratio can ensure the hot material gradation stable after secondary screening. In the mixing process, must not duo to the hot aggregate bin overflow or waiting to manually forced feeding hot aggregate bin, otherwise it will have larger error on mixture gradation. Under the premise to ensure the stability of raw materials, timely and accurately adjusting the feeding speed and feed rate of hot aggregate bin, to strengthen the inspection and cleaning for the sieve congestion, try to avoid overflow and waiting.
Because asphalt mixing plants adopt automatic weighting system, the key is accurate measurement that can ensure the quality of mix aggregate and the ratio mixture. It also is a key that regularly calibrated metering systems and laboratory extraction screening tracking check to control the mixture quality.
During the construction process, the aggregate gradation could not keep exactly and completely stable. Screen clogging is often the key factor influencing the mixture gradation. Among the production ratios that draw according to the target ratio designs and sieve mesh, the proportion of each heat silo should be set no less than 8%. Because each hot bin doors from open to close in the shortest time already discharge around 100g, so the right mesh should be make sure, the size range of hot bin should be expanded, cold material supply to achieve the ideal state.
Generally speaking, in order to ensure aggregate gradation stability in hot bin of the final layer, the last layer sieve should use a smaller screen size, such as commonly used 3mm x 3mm or 3mm x 4mm size, but with the contradiction that the screen size is too small prone to clogging, thus affecting the mix gradation, resulting in overflow. Under the premise of aggregate needle flake content, it is recommended to use 3mm x 5mm or 3mm x 10mm mesh. On the one hand through the “3” to ensure the fine aggregate gradation, particle size that is greater than 3mm can’t through the screen mesh. On the other hand, “5” or “10” can reduce the degree of congestion.
When asphalt concrete mixing, to control the temperature, whetstone and graded materials.
Oil-stone ratio control is the use of electronic weighing machine for a variety of materials weighting respectively.
The construction site laboratory should check the oil stone ratio at any time, as long as normal, the good equipment is not allowed to change the setting of various data. In the mixing process, the common is inaccurate asphalt concrete mixture ratio, Volatile oil content, fluctuated temperature, sometimes individual particle size deviation gradation curveted, etc. in a word, the failure of the mixture can not be played, only for waste disposal.
Feeding Belt Deviation Phenomenon Occurs, How to Correct It?
Below each silo with a set feeding belt conveyor, which is responsible for the silo in the aggregate to the aggregate belt. Its speed can be adjusted through the inverter, depending graded asphalt mixture may be needed. When the belt deviation phenomenon occurs, it can be corrected by adjusting the screw.
Such as when the corrugated sidewall belts deviation to the outside when the adjusting screw should pass through the outer bearing to the right will move until the belt is no longer wandering so far. And vice versa. But pay attention to the naughty tape process to grasp the principle, the belt tension should not be too small, too small belt slipping; too tight, it will cause abnormal stress roller bearings serious wear and power consumption, easy to premature failure of the belt..
The drying drum of asphalt batching mix plants
The structure of asphalt plant of different brands is different, main performance in the size of drying drum, internal partition, leaf blade layout form, etc.
The size of drying drum: in the drying drum, the aggregate complete heat exchange by means of continuous rolling forward in the material curtain. Therefore, under certain conditions, the length of drying drums can affect the transfer time of aggregate and heat in the drum and the diameter of the drum can affect the area and speed of the shade away. In this sense, the size of the drum is proportional to its drying capacity, namely the large enough size of drum is one of necessary factor to guarantee equipment production.
Internal partition and layout blade: blade of drying drum within special arrangement, points four areas (import area, shade area, radiation zone, discharge zone). The blades are not disposed in each region. The special protective blades, which are installed in the flame area, may be formed between the flame and the drum, reducing heat outward scattering.
The mixing methods of Continuous asphalt double drum recycling plant
The most important part of asphalt plant is “double drum”. As the name the drum has two layers, the outer cylinder fixed at work, the inner cylinder rotate. The internal structure of the inner cylinder is similar to the drying drum of asphalt batch mix equipment, and also the function of heating the aggregate letters. The difference is the inner cylinder and outer wall with large numbers of small impeller, which can completed the mixing function at the same time.
The Main Structure of asphalt batch mixing plant
Main Structure of asphalt batch mixing plant:
1.Cold Aggregate Supply System
Bin volume and number is customizable, Separated structure design significantly reduces dimensions for shipping and ensures a high capacity.
Two independent cold feeders and modular design, transport expediently.
Seamless ring belt, high reliability and long life.
Frequency convertor controlled SIEMENS motor, infinite variable speed adjustment, more accurate and energy saving.
2.Drying Drum
SIEMENS motors, hard-teeth reduction gear, friction driving, drum rotating stably.
Optimized lift blade design, make sure heating equably and high energy using ratio.
With 50mm insulating layer and stainless steel skin, avoid heat be lost.
3.Burner
Italy EBICO oil burner imported with original packing, high burning efficiency, diesel, diesel/heavy oil dual purpose or gas as fuel is optional.
With automatic flame failure protection devices for emergency.
4.Dust Collection System
Two level dust collection system (volute casing collector + bag house collector), with high and low temperature protection device for the system security.
Bag house collector using USA Dupont NEMEX bags, heat resisting and long life.
5.Mixing Tower
Both aggregate and filler elevators are equipped with a double ring chain bucket, which is more reliable and convenient for maintenance.
Twin shaft compulsory asphalt concrete mixer (the mixing arm is cross arranged with changeable gridded mixing blade), high mixing efficiency and long life.
SIEMENS motors with hard-teeth reduction gear, most stably and high performance.
Bitumen is sprayed into mixer through a special designed spray bar with high pressure to reduce feeding time and increase mixing uniformity.
Totally enclosed type circular vibration screen, modular design, vibration motor driving, low maintenance and long life.
Double layer much bigger hot aggregate storage hopper can effectively guarantee the continuity of the supply of hot aggregate; with 50mm insulating layer to avoid heat be lost.
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