Duplex Strainer

Updated: 2026-08-03

Overview

A dual basket strainer is a specialized industrial filtration device designed for continuous operation in pipelines. It consists of two parallel mesh baskets housed in a single body, allowing one basket to be cleaned or replaced while the other remains in service. This design eliminates the need for system shutdown during maintenance, making it ideal for critical processes in oil and gas, chemical processing, and water treatment plants. The strainer operates by diverting fluid flow through one basket at a time, trapping solid particles while allowing clean fluid to pass. When the active basket becomes clogged, a switching mechanism redirects flow to the clean basket, and the dirty one can be serviced. This redundancy ensures uninterrupted operation and protects sensitive downstream equipment like pumps, meters, and control valves.

Structure and Working Principle

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The dual basket strainer comprises a pressure vessel with inlet and outlet connections, two filter baskets with precision mesh screens, and a diverter valve mechanism. The body is typically constructed from durable materials like stainless steel (304 or 316) for corrosive environments or carbon steel for high-pressure applications. Each basket features a mesh screen with openings ranging from 10 to 200 microns, depending on the required filtration level. Fluid enters the strainer and is directed to one basket by the diverter valve. As the fluid passes through the mesh, particles are trapped while clean fluid exits through the outlet. A pressure differential gauge monitors the pressure drop across the active basket, indicating when cleaning is needed. When the pressure drop reaches a predetermined level (typically 5-10 psi), the diverter valve switches flow to the clean basket automatically or manually.

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进口滤网选购指南

本文解析进口滤网的核心价值与应用场景，对比不同材质特性，并提供维护建议，帮助工业用户优化过滤系统效能。

Key Features

The primary advantage of dual basket strainers is their continuous operation capability, which is crucial for processes that cannot tolerate shutdowns. The parallel basket design provides 100% standby capacity, ensuring no loss of filtration during maintenance. Modern versions often include sight glasses for visual inspection and blow-down valves for easy debris removal. These strainers are designed for high dirt-holding capacity, with some models handling several pounds of debris before requiring cleaning. They typically feature robust construction with ASME-rated pressure vessels, suitable for working pressures up to 1,500 psi in some configurations. Special versions are available for high-temperature applications (up to 750°F) or for handling viscous fluids like heavy oils.

Application Areas

Dual basket strainers are widely used in the oil and gas industry for protecting equipment in crude oil pipelines, refineries, and offshore platforms. They're essential for removing scale, welding slag, and other particulates that could damage pumps or clog control valves. In chemical processing plants, they safeguard reactors and heat exchangers from catalyst particles or polymer fines. The water treatment industry employs these strainers for intake screening at desalination plants and for protecting reverse osmosis membranes. Power plants use them in fuel oil lines and cooling water systems. Other applications include food processing (edible oil filtration), pharmaceutical manufacturing, and pulp/paper production where uninterrupted operation is critical.

Maintenance and Precautions

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Regular maintenance is essential for optimal strainer performance. The mesh baskets should be inspected and cleaned whenever the differential pressure increases by 5-10 psi over the clean pressure drop. Cleaning typically involves backflushing with clean fluid or manual brushing, depending on the design. The diverter valve mechanism requires periodic lubrication and testing to ensure proper switching. Installation precautions include proper orientation (most models are designed for horizontal mounting), adequate support to prevent pipe strain, and ensuring the upstream pipe is thoroughly cleaned before commissioning. Strainers should always be installed with isolation valves on both sides to facilitate maintenance. For critical applications, consider installing a bypass line with a coarse strainer to protect the system during basket replacement.

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滤网加工方法大全

本文详细介绍滤网的常见加工方法，包括编织法、冲压法、激光切割法等，分析各种方法的优缺点及适用场景，帮助读者全面了解滤网制造工艺。

B2B Procurement Guide

When procuring dual basket strainers, specify the required flow rate (in GPM or m³/h), operating pressure and temperature, and the filtration level (mesh size in microns). Material selection should match the fluid characteristics - stainless steel for corrosive media, carbon steel for high-pressure hydrocarbon service. Consider optional features like pneumatic actuators for automatic switching, differential pressure indicators, or Hastelloy components for extreme conditions. Lead times for custom-designed strainers can range from 8-12 weeks, while standard models may be available from stock. For reference, a 4" 150# stainless steel dual basket strainer for oil filtration typically costs $2,000-$3,500. Always request certified material test reports and hydrostatic test certificates. For large projects, consider factory acceptance testing to verify performance before shipment.