Working principle and application of roots blower
time：2023-02-16
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Generally speaking, the wind pressure of roots blower is 0.1MPa, and the air compressor is 0.6MPa.
There are two types of air compressors, one is volume type, the other is speed type. The volume type is divided into response type and rotation type. The velocity type can be divided into three types: axial flow type, centrifugal type and mixed flow type.
In the capacity type air compressor, the roots blower belongs to the rotary type, which is further divided into the rotor type.
Working principle: Roots blower is a volumetric blower, and the transport air volume is proportional to the rotation speed. Each time the three-blade impeller rotates, two impellers breathe and exhaust three times. The clearance between the impeller on the two shafts of the blower and the inner hole surface of the elliptical casing, the clearance between the impeller end face and the front and rear end covers of the blower, and the clearance between the impeller of the blower are always kept at a fine clearance. Driven by the synchronous gear, the air inlet of the blower is transported to the exhaust side along the inner wall of the casing.
Roots blower has no grease on the inner wall, compact structure, stable operation and stable quality.
Usage: Roots blower is widely used in chemical industry, smelting, wastewater treatment, aquaculture, light industry, mining, plastics, food, electricity, paper making, etc., It can transport gas, petroleum gas, radon gas, carbon monoxide, acetylene, etc. through mechanical seal. The stainless steel impeller is selected to transport corrosive and harmful gases such as water containing hydrogen chloride and hydrogen sulfide. Whether Roots blower can replace the air compressor leached in the process of cyanide gold extraction. This situation is actually complicated. What needs to be considered is the application situation (application load, meteorological factors, etc.) It should be noted that the roots blower itself is a high-pressure blower.
pressure
The pressure of the centrifugal fan refers to the variable pressure (compared with the atmospheric pressure), that is, the rising value of the air pressure in the fan or the difference of the air pressure at the inlet and outlet of the fan. It can be divided into negative pressure, dynamic pressure and total pressure. The performance parameter refers to the total pressure (equivalent to the difference between the total pressure at the fan outlet and the total pressure at the inlet), which is commonly seen in enterprises such as Pa, KPa, mH2O, mmH2O, etc.
flow
According to the gas volume of fan in unit time, it is also called air volume. Common Q shows that the common units are: m3/s, m3/min, m3/h (second, minute, hour). (Sometimes "mass flow" is applied, that is, according to the gas quality of the fan in a unit time. At this time, the close influence of the fan inlet gas density, gas composition, local atmospheric pressure, gas temperature and inlet pressure should be considered, and the customary "gas pressure" can only be obtained after conversion.
speed
Rotating speed of fan rotor. Generally, it indicates that n is the enterprise application r/min (r indicates the rate and min indicates the minute).
power
Power required to drive the fan. Common N means that Kw is applied to enterprises.
Common parameters and technical standards of fan
General ventilation, fan: total pressure P=.... Pa, m3/m3/flow Q=h, height (local atmospheric pressure), transmission mode, transport material (gas can not be written), impeller rotation, inlet and outlet angle of view (from the motor end), operating temperature T= ℃ (not written at normal temperature), motor model, etc.
High temperature fan and other fans:
Total pressure P=... Pa, m3/m3/flow Q=h, Kg/m3 intake density, transmission mode, transport material (gas can not be written), impeller rotation, inlet and outlet angle of view (from the motor end), operating temperature T= ℃, temperature T=... ℃, air inlet density □ Kg/m3, local air pressure (or local sea level), dust concentration, fan regulating valve, motor model, inlet and outlet expansion joint, overall base, hydraulic coupler (or frequency converter, liquid resistance driver), thin oil station, slow turning equipment, actuator, starting cabinet, control box, etc.
How to solve the gap of roots blower:
Because of the long-term use of roots blower, there will be cracks, especially in the case of high-speed operation, cracks on the casing often appear, which is not beautiful. If it is used for a long time, the casing will be damaged and fall off, which will affect the function characteristics of the whole fan.
1. Welding crack; If the crack of the fan casing is light, we don't need to repair it on a large scale, just weld it in the area with the crack. However, attention should be paid to the corresponding technology and temperature during welding to ensure welding.
2. Replace the casing; If the cracks in the casing of Roots blower are too large, the way we repair them is to replace the whole casing, so that we can ensure that the fan will work more stably when it is used again.
When cracks occur on the casing of Roots blower, we can handle them according to the above methods, such as slight cracks and welding. If it is too serious and there is a risk of falling off, we can repair it by replacing the casing, which is a good way to ensure the long-term use of the fan.
The problem of air pressure at the exhaust side of roots blower:
For Roots blower, when the rotor crosses the edge of the air outlet, when v0 space is connected with the exhaust side, because the air pressure at the exhaust side is high, some gases return to v0 space and suddenly increase the air pressure.
When the rotor continues to rotate, the gas leaves the pump. Each concave curved surface part of the rotor and the inner wall of the cylinder generate the working volume. When the gas moves to the vicinity of the air outlet during the rotor rotation, the gas is taken away from the suction port. Because of the high pressure, it is connected with the exhaust port. Once again, the pressure in the working volume suddenly rises, and then the gas is sent to the exhaust channel. The two rotors work in sequence. There is no contact between the two rotors, and the seals are tightly controlled by the clearance between them, so that the exhaust gas will not be contaminated by grease. The energy saving rate is positively correlated with the rate, that is, N%=△ N%. Although different from ordinary fans, the pump has a higher power saving rate, but because of its high power, it can run continuously for 24 hours as long as the furnace wall is not rotten. And it takes a long time to start, and some or soundproofing materials need to be replaced. The air filter screen, inlet valve, outlet valve and bypass pipe should be checked frequently and kept in good condition.
