(1) When the intermediate distance is the same and the outer radius is the same, the three-blade Roots blower with arc-shaped blades has a larger exhaust than the double-blade Roots blower. The displacement of the involute Roots blower has nothing to do with the number of rotor heads
(2) The vibration and noise of a three-lobe Roots blower is less than that of a two-lobe Roots blower. The life of the rotor bearing of a three-lobe Roots blower is about 15 longer than that of a two-lobe Roots blower. In addition, three-blade rotors can use twisted-blade rotors to reduce noise and vibration, but due to structural limitations, two-blade rotors cannot use twisted-blade structures.
(3)The mechanical performance of three-blade rotors is better than the double-blade rotors, like the gap between impellers and the gap between impellers and the case of pump.
(4) Three-blade Roots blower, especially twisted-blade Roots blower, has good noise and dynamic balance performance, so it has been more and more used in automobile supercharging.
Thirteen points for attention when installing a three-blade Roots blower
The three-blade Roots blower must be installed after purchase and delivery. This series of operations is not difficult, but you need to understand some of them before continuing. The impeller and shaft system of the three-blade Roots blower are of unidirectional structure, the impeller is not worn, and the performance of the fan is durable and stable for a long time. The three-blade Roots blower is large in size, efficient in use, compact in structure and flexible in installation.
The three-blade Roots blower rotates at high speed during operation, and vibration is caused by the pulsation of the air, which increases the vibration of the three-blade Roots blower. Therefore, when installing a three-blade Roots blower, it is necessary to fix it on the ground with screws and cushion it with impact-resistant feet.
According to the different models and sizes of the three-blade Roots blower, dig a 300mm deep square hole on the ground, 150*150mm wide, fill in the anchor bolts, and then connect the three-blade roots blower with bolts and nuts, using cement Concrete. Fill in the square hole. After the concrete is fixed, tighten the nuts to firmly connect the fan base and the concrete. This reduces the vibration displacement during the operation of the three-blade Roots blower and improves the operation of the equipment.
Notes for installation
1.The three-blade Roots blower should be installed on a firm ground with enough space around it to facilitate inspection, maintenance and maintenance.
2.The three-blade Roots blower should not be installed in a place with flammable, explosive or corrosive gas to prevent fire, poisoning or other accidents.
3.Keep the foundation level under the base of the three-blade Roots blower. In order to ensure the smooth operation and low vibration of the three-blade Roots blower, the four corners of the base must be equipped with damping rubber or cast with bolts.
4.According to the direction of the air inlet and outlet and maintenance needs, it is necessary to leave enough space around the foundation surface and provide a canopy for the outdoor configuration of the three-blade Roots blower.
5.The connecting pipe between the three-blade Roots blower and the system must be sealed and reliable. For small vacuum pumps, metal pipes can be used to connect gaskets and oil-resistant rubber. For small three-blade Roots blowers, vacuum hoses can be used for connection. The caliber requires shorter tubes and fewer elbows. (When welding the pipeline, the welding slag must be removed from the pipeline, and it is strictly forbidden to enter the vacuum pump cavity.)
6.In the connecting pipeline, the user can attach a valve and vacuum gauge above the inlet of the three-blade Roots blower to check the extreme pressure of the three-blade Roots blower at any time.
7.Connect the power supply according to the label of the three-blade Roots blower motor, and install the grounding wire, fuse and thermal relay of the corresponding specification.
8.When the three-blade Roots blower is energized and debugged, the motor belt can be removed to ensure that the rotation direction of the vacuum pump is in the specified direction before the vacuum pump can be used. (Turning to the protective cover to indicate the direction)
9.For the three-blade Roots blower with cooling water, connect cooling water if necessary.
10.If the solenoid valve is connected to the port of the three-blade Roots blower, the valve and the three-blade Roots blower must operate at the same time.
11.If the exhaust gas of the three-blade Roots blower affects the working environment, you can install a pipe at the exhaust port to pull it away or install an oil mist filter.
12.The three-blade Roots blower can be used for a long time at an ambient temperature below 40°C. When the temperature exceeds 40°C, cooling measures such as exhaust fans should be taken to extend the service life of the fans.
13.When the three-blade Roots blower transports air, biogas, natural gas and other media, the dust content should generally not exceed 100mg/m3.
Causes of motor burnout
1.The motor runs under phase loss
This is the main reason of the three-phase asynchronous motor. The three-phase load is a symmetrical load during the normal operation of the motor. Therefore, the three-phase current is basically balanced and equal in magnitude. If the motor is running out of phase (the phenomenon that any phase of the three-phase winding is disconnected is called Phase loss), the vibration of the three-lobe Roots blower will increase, abnormal sound will appear, the speed will decrease, the current will increase, the temperature of the motor will rise sharply, which will cause the motor to burn out, and the average quality of the motor will burn in at most ten minutes.
2.The bearing is damaged
Due to the uninterrupted operation of the three-lobe Roots blower for a long time, the motor body has a high temperature rise, and the bearing is not filled with grease in time, resulting in a lack of oil in the bearing until the bearing is damaged, shaft bending, belt fracture, etc., resulting in stator and rotor Friction (commonly known as sweeping bore) causes the temperature of the core to rise sharply, burns the slot insulation and the inter-turn insulation, and causes a short circuit between the winding turns or “fires” to the ground from the surface. In severe cases, the stator core will be inverted, misaligned, the rotating shaft will be worn, and the end cover will be scrapped.
3.When the air valve is closed, it will cause overload and burn
After the Roots blower is started, the air valve is not opened or the opening amount is not enough. However, the Roots blower is running under this condition, causing the operating temperature of the Roots blower motor body to rise sharply until the air outlet is burned or the air valve is reset, and the Roots blower is not turned off in time, and the Roots blower will also As a result, the operating temperature of the motor body rises sharply until it burns out. If the protection function is normal (appropriate thermal relay is installed), it will generally not happen. However, it should be noted that because the thermal relay cannot be calibrated, and the protection value is not very accurate, the selection is not appropriate, etc., and the manual setting is automatically reset, so when protection is needed, it often does not work, or it may After several protections, the real reason was not found, and the protection value was artificially increased. To invalidate the protection.
4.The motor is affected with damp
Reduced insulation caused by water or moisture in the power distribution cabinet or motor is also a common cause of damage, but there is no way to protect it. Only use caution and regularly shake the insulation. Before the motor explodes, it can be solved by drying and repainting. Especially for motors driven by inverters, you must be careful about this item, otherwise the inverter may be burned together.