ZG-L Series Automatic Backwash Filter

Description

The ZG-L Series Automatic Backwash Filter is manufactured with advanced technology and precision engineering. Its core component—the multi-column filter element assembly, delivers performance comparable to leading international products. This automatic filter reliably removes mechanical impurities from industrial circulating water and other liquid streams, ensuring stable system operation and reducing maintenance costs.

Structure & Operating Principle

The filter comprises a pressure vessel, filter elements(columns), a backwash mechanism, control system, drive unit, motorized valves, and differential pressure monitoring devices. A horizontal partition plate inside the vessel divides it into a dirty-water chamber and a clean-water chamber, with multiple filter columns mounted on the plate.

The feed liquid first enters the dirty-water chamber, passes through openings in the partition plate, and flows into the filter columns. Particles larger than the filtration gaps are retained on the filter medium, while the clarified liquid exits through the clean-water chamber outlet.

As retained solids accumulate on the filter elements, the pressure differential between the dirty and clean chambers increases. When the preset differential pressure is reached, the backwash cycle is triggered automatically via the differential pressure controller. The backwash can also be initiated manually as needed to discharge the collected solids.

Installation Methods

The automatic backwashing filter offers flexible piping configurations, with inlet and outlet available on the same side or on opposite sides. The motor can be selected as vertical or horizontal. Production and customization are available according to specific requirements.

Key Advantages

• Self-cleaning Function: The filter cleans each column using its own filtered liquid, so no column removal or auxiliary cleaning system is needed, and maintenance is simplified and does not require external cleaning equipment.
• Continuous Water Supply Function: Multiple columns operate in parallel; each is backwashed sequentially while others continue filtering, allowing online cleaning and uninterrupted discharge of contaminants, which maintains system productivity.
• Automatic Backwashing Function: A differential pressure controller monitors the ΔP between dirty and clean chambers; when the preset value is reached, it triggers backwash, and a timer also provides scheduled control, ensuring timely removal of accumulated solids.
• High-Precision, Reliable Filtration: The medium uses trapezoidal stainless steel wire on a multi-edged frame, offering high strength, scouring resistance, and corrosion resistance. V-shaped gaps trap particles, increase dirt-holding capacity, and ease release during backwashing.
• Large Filtration Area: Multiple columns provide an effective area over three times the inlet, minimizing screen and overall operating resistance, thereby reducing backwash frequency and allowing a compact vessel size and improving overall efficiency.
• Advanced backwash mechanism: The suction head makes elastic contact with the filter element, minimizing mechanical wear and ensuring reliable, durable backwash operation and effective drainage and preventing clogging.
• Sludge accumulation area: A dedicated bottom settling zone with a manual drain valve allows periodic removal of settled large particulates without interrupting normal filtration and maintaining flow stability.
• Filter Element Material: Standard elements are made of stainless steel （SS, e. g. 304 or 316） ; for highly corrosive liquid, duplex stainless steel (DSS, e. g. 2205 ) or super duplex stainless steel (SDSS, e. g. 2507 / UNS S32750), or TA2 are available.

Applications

• Water Supply Filtration – Surface water (rivers, reservoirs, lakes), groundwater, swimming pool water, and similar sources.
• Industrial Circulating Water – Cooling towers, chillers, heat exchangers, and other closed-loop recirculating systems.
• Process Water – Steelmaking, chemical processing, power generation, automotive manufacturing, pulp & paper, and other industrial applications.
• Wastewater Treatment – Pre-filtration ahead of multi-stage treatment trains to reduce downstream processing costs.
• Corrosive Liquids – Seawater, brackish water, acids, alkalis, and other aggressive fluids.

Technical Specifications:

For Vessel Diameter≤DN600 For Vessel Diameter＞DN600

Model & Specification

Notes:

① The above are the parameters of the standard product. Customization is available.

② Model description: ZG□1□2 -L.□3□4
□1: Inlet/Outlet Dimensions
□2: Vertical
□3: Capacity per Unit
□4: Filter Type