SZS series screens are used for the removal of fine impurities during the tertiary treatment stage at municipal wastewater treatment plants and are designed to protect natural water bodies (receiving waters) from small debris.
Design and Operating Principle
The SZS screen consists of a frame with an internally mounted filter media, a drive system, a stripper, and rakes. The filter media is composed of filter cassettes with a fixed opening (gap). The screen opening determines the size of the particles removed from the wastewater. Debris particles exceeding the opening size are retained on the filter media, while the clarified liquid passes through it and is directed for further treatment.
A gear motor powers the drive shaft equipped with sprockets, which transmit motion to the drive chain. The chain slides along polymer guides. Rakes attached to the chains capture debris from the wastewater flow and move it along the filter media to the stripper, which directs the waste into a receiving hopper or a conveyor system.
To prevent failure due to excessive loads, the screen is equipped with both electrical and mechanical protection systems.
Specifications
| № | Parameter | Value |
|---|---|---|
| 1 | Channel Width, mm | 600...3000 |
| 2 | Channel Depth, mm | 600...7000 |
| 3 | Aperture Size, mm | 0,05...3 |
| 4 | Installation Angle, deg | 60 |
| 5 | Motor Power, kW | 0,37...1,5 |
| 6 | Frequency, Hz | 50 |
| 7 | Voltage, V | 380 |
| 8 | IP Rating | IP68 |
| 9 | Material | Structural Steel or Stainless Steel Grades AISI 304, AISI 321, AISI 316 |
Automation & Equipment Protection
Depending on the specific technical requirements, the screen can be configured with several automation modes:
- Timer-based control. The screen operates in a pre-configured cyclic mode based on set time parameters, adjusted for peak and minimum load periods.
- Differential level control. By default, the screen is in standby mode. Sensors installed in the channel upstream and downstream of the screen detect when the water level reaches a setpoint and trigger the operating cycle. As the debris load decreases and the liquid level in the channel drops, the screen automatically shuts down.
- Custom programming. The screen can be integrated into any non-standard algorithm or operate under the control of any existing PCS (Process Control System) as per the Customer’s requirements.
The screen is equipped with an automatic drive interlock. In the event of an emergency, the drive is deactivated, audible and visual alarms are triggered, and a fault message is displayed on the operator's interface.
Equipping the screen with a VFD-controlled (Variable Frequency Drive) electric motor allows for adjusting the rake speed. It also enables the integration of the equipment suite into a unified system with a centralized control hub and connection to a remote monitoring (telemetry) system. Screen operation can be managed both remotely and via a local control panel.
Features
- Ultrafine Liquid Flow Screening. Designed for superior removal of microscopic particles from the effluent.
- Precision Opening Size. Filtration gap starting from 0.05 mm.
- Dual-Stage Protection. Features two layers of safety: electrical protection via a Variable Frequency Drive (VFD) and mechanical protection through a torque-limiting coupling.
- Wide-Range Rake Speed Control. Allows for precise adjustment of rake travel speeds across a broad operating range.
- Mechanical Resilience. High resistance to physical impact and mechanical damage.
- High Maintainability. Engineered for ease of service, ensuring high equipment availability and simplified repair procedures.