Backwash Strainer

Backwash strainer is a self-cleaning inline filtration device that removes accumulated impurities from filter elements through reverse fluid flushing, eliminating the need to shut down pipelines, disassemble housings or manually take out mesh baskets for cleaning. It serves as an advanced upgrade to conventional Y-type, T-type and basket strainers, perfectly suited for large-flow, long-running industrial pipelines carrying media with high volumes of suspended solids, sediment, rust scale and particulate contaminants. Installed upstream of pumps, heat exchangers, compressors, flow meters and precision control valves, it delivers continuous filtration while automatically restoring screen permeability without interrupting production.

The whole unit consists of a heavy-duty strainer body, multi-layer reinforced stainless steel filter cartridge, backwash drain port, switching valve and differential pressure detection components. Under normal forward filtration mode, medium flows from the inlet and penetrates the fine mesh of the internal cartridge; clean fluid proceeds downstream, while solid pollutants are trapped on the inner or outer surface of the filter screen. As debris accumulates, the pressure gap between the strainer’s inlet and outlet gradually widens. Once the preset differential pressure value is reached, the control system activates the backwash cycle. The internal flow direction reverses instantly, and high-speed reverse fluid impacts the clogged screen surface powerfully. All caked sediment and particles are stripped away and flushed out through the dedicated drain outlet within several seconds. After backwashing finishes, the switching valve resets automatically, and the strainer returns to standard filtration operation. Many models also support timed backwashing as an alternative control logic for stable working conditions with predictable impurity levels.

Unlike basic automatic drain strainers that only discharge partial dirt with forward flow, the reverse flushing design of backwash strainers achieves far more thorough cleaning effect. The counter-flow scouring force dislodges sticky fine particles that ordinary side draining cannot remove, maintaining stable filtration efficiency and low pressure loss over extended operation cycles. The filter cartridge is made of 304 or 316 stainless steel woven mesh or perforated metal plates, with customizable mesh sizes ranging from coarse separation to ultra-fine precision filtration to match water, oil, low-temperature steam and weakly corrosive chemical fluids. Strainer bodies are manufactured from ductile iron, carbon steel or full stainless steel to satisfy different pressure, temperature and corrosion requirements, with standard pressure grades PN16, PN25 and Class 150, and flange, grooved or welded connections covering DN50 up to DN600 for both branch pipes and main trunk lines.

Installation flexibility is a major strength. The strainer can be mounted horizontally or vertically, with the drain port arranged downward to facilitate gravity-assisted waste discharge. Operators can adjust backwash duration, differential pressure trigger threshold and flushing frequency locally via the control cabinet according to actual impurity concentration. The fully enclosed structural design prevents medium splashing during backwashing, improving on-site safety and keeping equipment rooms tidy. Since disassembly is rarely required, wear and tear on sealing gaskets and flange joints is greatly reduced, lowering long-term leakage risks and replacement costs of spare parts.

Traditional manual strainers require regular system shutdown and manual screen cleaning, which leads to production downtime, heavy labor workload and potential pipeline blockage if maintenance is delayed. Backwash strainers completely resolve these pain points by enabling online, non-stop self-cleaning. Their large dirt holding capacity and powerful reverse flushing cut maintenance intervals drastically, making them ideal for unattended pump stations, remote industrial facilities and large-scale circulating water systems.

Core Advantages

Reverse backwash self-cleaning system realizes online maintenance without pipeline shutdown or production interruption

Dual automatic control modes: differential pressure trigger and fixed timing cycle for diverse working conditions

Powerful counter-flow scouring thoroughly removes sticky fine impurities, maintaining stable long-term filtration performance

Reinforced stainless steel filter cartridge features strong abrasion resistance and extended service life

Multiple body materials and connection types adapt to water, oil, steam and mild corrosive industrial media

Minimal manual intervention drastically reduces labor maintenance expenses and inspection frequency

Fully sealed flushing structure avoids liquid splashing and medium leakage during sewage discharge