1. Purpose of the Equipment
The inverted umbrella aerator is a crucial piece of equipment in biochemical wastewater treatment.
The machine is primarily used for industrial wastewater treatment in industries such as petroleum, chemical, leather, paper, pesticide, gas, and coal.
It is also suitable for the treatment of municipal domestic sewage.
In aeration tanks utilizing the activated sludge process, it oxygenates and mixes the liquor to propagate aerobic bacteria, thereby achieving rapid and efficient wastewater purification.
2. Core Structure & Features
The aerator features several designs aimed at improving operational efficiency.
- Components: The machine consists of a motor, coupling, reducer, lubrication system, lifting platform, inverted umbrella base, and impeller.
- Inverted Umbrella Impeller: It offers high power efficiency, a wide mixing area, prevents clogging, and can rotate both forwards and backwards.
- Specialized Reducer: It uses a three-stage helical gear reducer characterized by high transmission efficiency, low noise, and a long lifespan.
- Flexible Adjustment: The impeller lifting device allows for the random adjustment of the immersion depth to regulate the oxygenation amount according to process needs.
- Speed Control: The equipment uses a variable-frequency drive (VFD) control cabinet to adjust the motor speed.
3. Working Principle & Oxygenation Mechanism
Submerged under the water surface, the impeller oxygenates and mixes the sludge through the following three actions:
- Surface Renewal: The spraying and suction actions of the impeller cause the wastewater to circulate rapidly up and down, exposing oxygen-deficient wastewater to the air for high-speed oxygen absorption.
- Hydraulic Jump: The impeller throws water outward in a low-trajectory pattern, creating a hydraulic jump that mixes with the air for oxygenation.
- Negative Pressure Suction: As the impeller rotates, a low-pressure zone forms behind the blades, drawing in air for oxygenation.
4. Installation & Adjustment Specifications
Proper installation is the prerequisite for stable equipment operation.
- Foundation Leveling: The initial coarse leveling error of the base plate must not exceed 0.10/1000. After the cement hardens, final calibration is required, and the horizontal error must not exceed 0.05/1000.
- Coupling Adjustment: For the flexible coupling connecting the reducer's drive shaft and the motor, radial displacement must be ≤0.3mm. The shaft tilt must be <1°.
- Rotation Direction: When looking down at the equipment, the impeller should rotate in a clockwise direction.
5. Test Run & Routine Maintenance
Standardized testing and maintenance can effectively extend the life of the equipment.
- No-load and Load Testing: A no-load operation at the rated speed for no less than 2 hours is required first. After normal no-load operation, a load test should be conducted to ensure there is no impact vibration and no oil leaks at any seals.
- Oil Replacement: Two weeks after the new aerator operates under load, the dirty oil must be drained and replaced with fresh oil. Afterward, during long-term operation, the oil should be replaced every 4-6 months.
- Temperature Monitoring: Oil temperature should be observed during daily operation; if the temperature rise is >30°C, the machine must be stopped to find the cause and repaired before further use.
- Dehydration Prevention: If impeller dehydration occurs (indicated by a drop in current and the disappearance of the hydraulic jump), oxygenation drops sharply, and the machine must be stopped immediately for inspection. If a vortex forms due to a small pool diameter, baffle plates that protrude above the water level can be installed to weaken the rotational flow.
