With the rapid development of society, the design and selection of concrete batch plant dust collectors are very important. It can improve the dust removal efficiency of the plant and make the application of concrete batch plants more effective. In this article, we analyze the application of dust removal design and equipment selection in a concrete mixing plant and propose the corresponding optimization measures.
A dust collection system is an air quality improvement system used in industrial, commercial, and home production shops. In the process of concrete mixing, a holistic dust removal design is usually required. However, in the overall application process, the various design methods will change accordingly. Therefore, in order to improve the overall dust removal efficiency, it is necessary to combine the various mixing methods of the mixing plant for a comprehensive dust removal design, so as to achieve a good dust removal effect.
Sources of dust in concrete plants
Aggregate feeding
In the process of concrete mixing, it is necessary to pay more attention to the work of aggregate feeding. Generally, in the process of transferring sand and gravel from the aggregate bin to the weighing hopper, attention should be paid to the distance between the belt conveyor and the corresponding dust collection material.
Under normal circumstances, there will be a certain drop between the two. Then this time, during the process of transmission, it is very easy to produce a certain amount of dust, thus causing a certain degree of loss. Therefore, from the point of view of cost, the equipment should be configured in such a way that it shares a set of dust removal equipment with other weighing hoppers, instead of being set up separately.
Weighing hopper loading
The process of loading the weighing hopper also generates a large amount of dust, such as cement, fly ash, swelling powder, etc. This is also the time when some consideration needs to be given to its cost. Certain measures are taken to save costs and to further improve the efficiency of the work.
Mixing material feed to the host
During the process of mixing and loading, a large amount of dust is also generated. In this case, the dust particles produced not only reduce the utilization rate of raw materials but also cause some pollution to the working environment to a certain extent.
Storage silo
For the use of the storage bin, in addition to taking into account the dust generated during the beating because of the drop up and down, it is also necessary to take into account the pressure generated by the inner bin during the beating process. Therefore, in the actual work process, we should consider and analyze the two aspects of dust removal and pressure release in the silo, and put forward the corresponding solution measures.
Selection of concrete batch plant dust collectors
Selection of cartridge materials and structural forms
In the selection of dust removal equipment, it must be strictly selected according to the actual work requirements. This has very high requirements on the cartridge, both for the material and the structure of the cartridge. In the process of filter element selection, first of all, we must ensure a certain selection of materials on the basis of a good filtration effect and high filtration efficiency, so as to ensure that the filter element can have a relatively long service life.
In the filtration of dust, the effect of filtration is inextricably linked with the material step, quality, size of the particles, and speed of its work.
Selection of dust collector type
In addition to the high requirements for cartridge selection, the choice of dust collector is also important when configuring the equipment. At present, the pulse blowback dust collector is the most widely used. This type of dust collector can be used in a relatively high-pressure environment to blow the dust in high-pressure air in the form of pulses inside the cartridge, and blow off the adhering cartridge surface.
From the actual use, the dust removal rate of this type of dust collector is very high and has a very good dust removal effect. The life of the equipment can be extended to a large extent and the maintenance cycle of the equipment can be further extended. In addition, there is another dust removal method that is also very widely used. It is mainly through mechanical vibration that the dust on the surface of the cartridge is shaken off. However, in terms of dust removal rate, its effect is far less than the former.
Selection of dust removal area of storage silo
According to the formula can measure the safety factor K generally takes the value of 1.2 ~ 1.4. When the larger the area of the silo, the stronger the ability to relieve pressure, it will obtain a smaller value. The air volume can be measured in the following example, the air volume of the bulk powder tanker can be used as the basis of calculation, in general, the rate of 600~1300m3/h per hour. for example, if the cement bin of the silo is 200t, the area of the dust collector with vibration type is 24m2.
According to the actual processing experience, when the cement truck carries out a long time to beat the material, in every interval of 1.5 to 2 hours, it is necessary to pause and carry out vibration cleaning of the silo roof, and then carry out the work of beating material again, so that the dust collector can have sufficient ventilation. When the dust collector area of the silo needs to be increased, a pressure release device needs to be installed at the top of the silo in order to ensure the safety of silo.
The application of concrete batch plant dust collectors
For a mixing plant, it is necessary to choose a dust collector with the right area. Installing a dust collector in a mixing plant will make the weighing hopper produce a certain negative pressure, which will eventually affect the accuracy of the powder weighing and the dust removal effect will become worse.
About the application of negative pressure generated by the weighing hopper
After conducting tests and technical analysis in the field, the most fundamental reason for some problems is that: in the two closed space mixing host and weighing hopper, when the extractor fan is working without air, the air inside the extractor fan will be pumped out in one direction, which will generate a certain negative pressure.
When the selected extractor fan is small, the above problem can be solved by adding a make-up air hole. When the induced draft fan is working, clean air can come in from the make-up air hole, and the dusty air in the weighing hopper can be sucked into the dust chamber and discharged after filtering operation by the induced draft fan, making a convection situation between the air. The specific operation is as follows.
A small hole is made in the steel plate of the weighing hopper, and a small skeleton filter bag can be attached with bolts after welding a short section of steel pipe, which can be the product to clean the confined space. As there is no source of air, when the extractor fan works, its internal air can only be pumped out in one direction, thus generating negative pressure. If you choose a smaller extractor fan, the specific size should be measured in the field.
For the choice of filter bag material, you need to choose easy-to-clean ash, with good permeability of the material. This will ensure that the filter bag has a long service life. The other method is through a tube that can be connected to the mixing host and weighing hopper between the channel so that the dust-containing air in the weighing hopper can be introduced into the host. By means of an induced air duct in the main machine, the dust collecting hopper in the dust collector can be directed into the flange on the side. This extends the working distance and at the same time minimizes the impact of the induced draft fan on the weighing hopper.
About the application of positive pressure generated by the weighing hopper
A small hole needs to be opened in the main unit, then a short section of pipe needs to be welded, then a pipe with an elbow needs to be connected, and the clamp needs to be fixed down with the head. The air-fill hole should be located away from the dusty air outlet. In the process of using the weighing hopper, it is necessary to combine it with the mixing form of the mixing plant and adopt various ways to keep the overall air pressure in a balanced state. The final result is a good mixing effect.
The solution to the problem of weakening dust removal effect
Connecting the lead air pipe of the mixing host to the bottom of the dust collector hopper is to be able to facilitate users and saves cost as much as possible. Under the suction of the fan, the dust blown down by the pulse is not able to settle to the bottom, so the cartridge is always surrounded by dust. When the dust does not settle, the efficiency of the dust collector will be greatly reduced. According to the actual operation, for dust collection, a pneumatic butterfly valve should be installed which can be controlled automatically by the system. It can be opened regularly to discharge the dust into the mixing machine, which greatly reduces the labor intensity.
Comprehensive above, for the correct design and reasonable selection of dust removal equipment, while avoiding atmospheric pollution, it can improve the overall performance of the mixing plant.
In the process of dust removal design, it is usually necessary to use a variety of design methods to improve its integrity. At the same time, the science and rationality of the de-dusting design should be strengthened. The selection of dust removal equipment should be discussed comprehensively and combined with the specific conditions of the mixing plant so that the design of dust removal is well-targeted to achieve the desired design effect.
Read more3 types of concrete batch plant layout
Talking About 4 Influences of Water-Binder Ratio on Concrete