Dust conveying Roots blower improves environmental efficiency and solves powder suction problems
Dust conveying Roots blower is a gas conveying equipment specifically designed for conveying particulate materials such as dust. Here is a detailed analysis of it:
1、 Definition and Working Principle
1. Definition: The Roots blower for dust transportation is a positive displacement blower that relies on the change in working chamber volume formed by the rotation of two involute "8" shaped rotors to transport gas.
2. Working principle: The working principle of Roots blower is the same as that of gear pump, that is, each rotor is equivalent to a gear with only two teeth. Each concave curved surface on the rotor forms a working volume with the inner wall of the cylinder. During the rotation of the rotor, gas is taken away from the intake port. When it is moved to the vicinity of the exhaust port and connected to the exhaust port, there is a sudden increase in pressure in the working volume due to the reflux of high-pressure gas. Then, the gas is transported to the exhaust channel. The two rotors are not in contact with each other and are sealed by a tightly controlled gap, so the discharged gas is not contaminated by lubricating oil.
2、 Characteristics and advantages
1. Energy saving: Roots blower delivers much higher concentration than centrifugal blower, resulting in lower energy consumption.
2. Long conveying distance: Roots blowers have a longer conveying distance and require less installation space.
3. Small pipeline diameter: Under the same conveying capacity, the diameter of the Roots blower pipeline is much smaller than that of the centrifugal blower pipeline, and the cost of pipeline and support civil engineering is small, with less initial investment.
4. Less equipment investment: Under the same dust conveying capacity, Roots blowers require smaller exhaust dust collectors and require less equipment investment.
5. Low maintenance cost: Roots blower has a simple structure, easy maintenance, and long service life.
3、 System composition and key components
1. Soundproofing room and muffler: The Roots blower produces loud noise, so it is necessary to install the main part of the Roots blower in the soundproof room and install a muffler at the outlet of the Roots blower to reduce its operating noise.
2. Rotary feeder: installed between the dust spiral outlet at the bottom of the bag filter and the acceleration chamber, requiring good sealing and wear resistance.
3. Acceleration chamber: The acceleration chamber is a critical part of the Roots blower dust conveying system, with its upper end connected to the outlet of the rotary feeder and its horizontal ends connected to high-pressure pipelines. The angle of the chute at the discharge port of the acceleration chamber and the cross-sectional area entering the main pipeline are strictly required.
4. Pipe bends and inspection doors: Due to the long distance of high concentration dust transportation, the air ducts are often arranged in a more directional manner, which may occasionally cause pipeline blockage during power outages or other reasons. It is necessary to arrange a number of inspection doors at straight pipes and bends so that blockage can be cleared section by section.
5. Check valve: A fireproof check valve needs to be designed and installed between the end of the air duct and the bag filter. When the Roots blower starts running, the check valve automatically opens. When a fire occurs in the end bag filter, the check valve will automatically close due to its own weight after the Roots blower stops, isolating the end filter from the conveying pipeline.
6. Spark automatic detection and fire extinguishing system: Due to the high concentration and long distance of dust transported by Roots blower, and the fact that dust belongs to flammable and explosive materials, the design and installation of spark automatic detection and fire extinguishing system is particularly important.
4、 Application Fields
Roots blowers are widely used in the field of dust transportation, such as conveying wood dust in particle board factories, conveying flour in grain processing, conveying plastic particles, pigments, catalysts and other powder raw materials and products in the chemical industry, as well as transporting bulk cargo such as coal and ore at ports and terminals.
5、 Usage and maintenance
1. Usage requirements:
The temperature of the intake medium transported shall not exceed 40 ℃.
The particle impurity content in the medium should not exceed 1000mg/m3, and the particle size should be below 0.1mm.
When using boost, the rated boost value specified on the blower nameplate must not be exceeded.
2. Start preparation:
Open the intake control valve, exhaust control valve, and bypass pipe.
Check if the air filter at the inlet is unobstructed and if the inlet of the filter is open.
Check whether the pipes, valves, mufflers, and air filter supports are stable.
Check if the lubricating oil is in good condition, if the model is appropriate, if the depth of the lubricating oil layer should reach 3-5 centimeters above the specified oil line, and if the cooling water system is unobstructed.
Move the coupling and check if the impeller is moving smoothly and if there is any friction or collision.
Check if the connections of each part are good and if there is any looseness.
Surrounding debris, keep there no debris within two meters of the fan.
Check if the electrical components and voltage reducing starting equipment are intact.
Check whether the maintenance tools are complete and whether the fire-fighting equipment is sufficient.
3. Start and Run:
When starting the Roots blower, it should be run empty for 20-30 minutes first, and observe whether there are any abnormal phenomena in the blower. If there is any impact or friction sound, it should be stopped immediately for inspection and troubleshooting.
After the empty machine runs normally, the load can be turned on.
After the fan is running normally, gradually adjust the outlet valve (or gradually close the vent valve) and gradually load it to the rated pressure, but do not overload it.
Do not close the inlet and outlet gate valves when starting up, and do not suddenly stop when fully loaded.
In summary, the Roots blower for dust transportation has many advantages and a wide range of application fields. In the process of use and maintenance, it should be strictly carried out in accordance with the usage requirements and operating specifications to ensure its stable and smooth operation.
