Overview
The rotary screen bar screen cleaner, as the core front-end pretreatment equipment in the water treatment process, realizes the efficient interception of solid impurities in sewage through the continuous rotary movement of the chain screen, and is an indispensable "first line of defense" in municipal sewage and industrial wastewater treatment systems. Its technological core lies in using the mechanical transmission of the rake chain to separate floating objects, fibers, branches and other impurities from the sewage and transport them to the slag hopper, solving the pain points of frequent manual cleaning and low interception efficiency of traditional screens. Compared with traditional equipment such as trash screens and primary sedimentation tanks, this equipment can increase the removal rate of solid impurities to over 90% and can operate continuously for 24 hours. It is especially suitable for the pretreatment of large-flow water bodies and has become a standard configuration in urban sewage treatment plants, food processing plants, textile printing and dyeing plants and other places.
Core Working Principle and Structural Innovation
I. Analysis of the Dynamic Interception Mechanism
1. Rake Chain Transmission System
It is composed of stainless steel rake teeth hinged into an endless chain at a certain spacing. Driven by the driving sprocket, it rotates at a constant speed (linear speed of 0.5 - 1.0m/min). When the rake chain passes through the screen bars, the impurities in the sewage are intercepted in the gaps between the rake teeth, lifted to the top of the equipment along with the chain, and then the impurities are unloaded into the slag hopper by the scraper. This cyclic action of "interception - lifting - unloading" realizes the continuous removal of impurities.
2. Optimization of Screen Bar Spacing
The spacing between the screen bars can be adjusted according to the characteristics of water quality (usually 5 - 50mm). For municipal sewage, a spacing of 10 - 20mm is often selected to intercept large particle impurities such as branches and plastic bags, while for industrial wastewater, it can be refined to less than 5mm to intercept fibers, debris, etc.
II. Structural Design Advantages
1. All-Stainless Steel Anti-Corrosion System
The rake teeth, chains and screen bars are all made of 304/316L stainless steel. The surface is treated by electrolytic polishing, and it can withstand a Cl⁻ concentration of up to 5000ppm in sewage. In corrosive environments such as seawater and chemical wastewater, its service life exceeds 10 years.
2. Intelligent Overload Protection
Equipped with a torque sensor and a frequency conversion control system, when the load caused by impurity blockage exceeds the set value (such as 150N·m), the system will automatically stop and alarm, avoiding failures such as chain breakage. Its response speed to mechanical overload protection is three times faster than that of traditional ones.
3. Underwater Transmission-Free Design
The driving device is placed on the top of the equipment, avoiding the wear of underwater bearings. Combined with the motor with an IP68 protection level, it can operate stably in humid environments, and the maintenance cycle is extended to 6 - 12 months.
Analysis of Typical Application Scenarios
1. Municipal Sewage Treatment
A certain urban sewage treatment plant uses a rotary screen bar screen cleaner (with a treatment flow of 2000m³/h and a screen gap of 15mm) as pretreatment equipment. It intercepts about 3 tons of domestic garbage, branches and other impurities on average every day, reducing the failure rate of subsequent pumps and aeration equipment by 70%. The equipment is equipped with an automatic flushing system (0.8MPa high-pressure water), which cleans the rake chain every 2 hours to prevent sludge adhesion from affecting the interception efficiency.
2. Food Processing Wastewater Treatment
In the wastewater treatment of meat processing enterprises, the rotary screen bar screen cleaner (with a screen gap of 8mm) can effectively intercept impurities such as minced meat, hair and packaging debris. A case study of a slaughterhouse shows that after half a year of equipment operation, the sludge removal cycle of the subsequent sedimentation tank is extended from 1 month to 3 months, and 70% of the intercepted solid waste can be recycled as feed raw materials, achieving the dual benefits of "pollution reduction + resource utilization".
3. Textile Printing and Dyeing Pretreatment
For the impurities such as chemical fiber and sizing agents in printing and dyeing wastewater, a stainless steel rotary screen bar screen cleaner with a screen gap of 5mm is selected. Combined with a backwashing device (assisted by compressed air), it can intercept more than 95% of fiber impurities, avoiding their winding and clogging of subsequent membrane components. After the transformation of a certain printing and dyeing factory, the membrane replacement cycle is extended from 3 months to 1 year, saving 800,000 yuan in annual consumable costs.
4. River Ecological Restoration
In the treatment project of black and odorous water bodies, the mobile rotary screen bar screen cleaner (equipped with a diesel-driven system) can be temporarily deployed at the entrance of the river to intercept floating garbage, water hyacinth and other aquatic plants, creating conditions for ecological restoration. In a certain river treatment project, the equipment treats 5000m³ of water on average every day, reducing the coverage rate of floating objects in the river from 80% to below 5%.
Technical Advantages and Industry Value
1. Automation and Efficiency Breakthroughs
- Unattended Operation: Through PLC programming, the dual-mode control of "timed operation + differential pressure trigger" is realized. At night, it can automatically switch to the energy-saving mode (interval operation), reducing the operation and maintenance costs by 80% compared with manual inspection;
- High Flow Adaptability: The maximum treatment flow of a single piece of equipment can reach 5000m³/h, which is suitable for large sewage treatment plants, reducing the number of equipment and floor space.
2. Convenient Maintenance Design
- Automatic Chain Tension Adjustment: Built-in spring tensioning device can compensate for the slack caused by chain wear without manual adjustment;
- Modular Components: The rake chain can be disassembled and replaced in sections. The maintenance time for a single section is less than 2 hours, shortening the shutdown time by 75% compared with traditional screens.
3. Environmental Protection and Economy
- Low Energy Consumption Operation: The driving power is only 1.5 - 5.5kW, and the energy consumption for treating each ton of water is less than 0.01kW·h, saving 40% energy compared with the grab bucket type screen;
- Solid Waste Reduction: The moisture content of the intercepted impurities is less than 80%, which is convenient for subsequent compaction treatment and reduces the amount of garbage removal by more than 30%.
Selection and Maintenance Guidelines
I. Key Selection Factors
- Flow Matching: Select the equipment specification at 1.2 times the maximum design flow. For example, for a 1000m³/h system, an equipment with a treatment capacity of 1200m³/h should be selected;
- Screen Gap Precision: Select 10 - 20mm for municipal sewage, 5 - 10mm for food wastewater, and 3 - 5mm for textile wastewater;
- Material Adaptability: Select 316L stainless steel for oily wastewater and duplex stainless steel (such as 2205) for seawater environment to ensure corrosion resistance.
II. Maintenance Optimization Strategies
1. Daily Inspection
- Check the running status of the chain every day and remove the entangled fiber impurities;
- Check the oil level of the driving device (gear oil ISO VG 150) every week to ensure good lubrication.
2. In-depth Maintenance
- Conduct ultrasonic cleaning on the rake chain every quarter to remove stubborn sludge;
- Test the elongation of the chain every year. When the elongation exceeds 3%, replace the new chain to avoid tooth jumping failure.
Industry Development Trends
With the promotion of smart water affairs and green manufacturing, the rotary screen bar screen cleaner is developing in the directions of intelligence, modularization and resource utilization:
- Internet of Things Integration: Install vibration sensors and remote monitoring modules to upload the equipment operation data in real time. Through AI algorithms, predict the risk of failure and reduce unplanned shutdowns by 50%;
- Application of New Materials: The wear resistance of graphene-modified stainless steel rake teeth is doubled, and the service life is extended to 15 years in the environment with high-hardness impurities;
- Coordinated Treatment Technology: Integrated with crushers to realize the integration of "interception - crushing", reducing the volume of solid waste by 50% and facilitating subsequent incineration treatment.
Conclusion
The rotary screen bar screen cleaner redefines the standard of water treatment pretreatment with its technical characteristics of "automatic interception, high efficiency and low energy consumption". From urban pipe networks to industrial production lines, its reliable mechanical transmission and intelligent control have solved the efficiency bottleneck of traditional solid waste interception. In the future, with the progress of sensing technology and materials science, this equipment will play a more crucial role in fields such as sponge cities and river basin governance, and become an important support for the intelligent upgrading of water environment governance.
