Stainless Steel Duplex Filter

A stainless steel duplex filter removes undissolved salts, suspended solids, and fermentation residues from liquid fertilizer without stopping production. It uses two filter housings connected by a three-way valve, so one housing can be cleaned or serviced while the other continues to supply the line.

LANE Machinery supplies SS304 and SS316L duplex filters for liquid fertilizer, with models from 2 to 10 m3/h, 60 to 400 mesh filter options, polished internal surfaces, quick-open covers, and optional CIP connections. The filter can be supplied as a single unit or integrated into a complete liquid fertilizer production line.

Product Overview

The LANE stainless steel duplex filter is a parallel filtration unit designed for continuous production. It protects storage tanks, filling machines, drip irrigation systems, and spray equipment from particles that cause clogging and quality complaints.

Each unit consists of two independent filter housings, a three-way ball valve, filter bags or baskets, and a support structure. The operator can switch flow from one housing to the other without interrupting the process, then clean the loaded housing and return it to service.

The filter is suitable for water-soluble NPK, liquid NPK, foliar fertilizers, chelated micronutrient solutions, organic liquid fertilizers, and fermentation products. It can be configured for single-stage or multi-stage filtration depending on the product clarity required.

Features and Advantages

Continuous duplex filtration

• Two filter housings operate in parallel or standby mode.
• Product flow continues while one housing is cleaned or serviced.
• Changeover is controlled manually or automatically by the PLC.
• Prevents production stops on filling lines and downstream equipment.

Corrosion-resistant stainless steel construction

• SS304 is standard for housings, covers, and internal parts.
• SS316L is available for chloride, acid, and aggressive fertilizer chemistry.
• Inner and outer surfaces are polished to reduce residue and simplify cleaning.
• Material certificates are available for traceability.

Wide filtration range

• Bag and basket filters cover coarse to fine grades.
• Typical range from 60 to 400 mesh depending on product.
• Multi-stage configuration removes large particles first, then fine particles.
• Filter media can be changed to match different formulations.

Quick-open design for fast maintenance

• Quick-open top covers allow fast bag or basket replacement.
• Three-way ball valve switches flow without draining the system.
• Vent valve removes air during startup.
• Adjustable feet keep the unit stable on uneven floors.

Pressure monitoring and line protection

• Inlet and outlet pressure gauges show filter loading.
• Differential pressure monitoring signals when media needs cleaning.
• Low operating pressure protects pumps and downstream valves.
• Optional automatic backwash reduces manual handling.

CIP and automation options

• CIP connections allow cleaning without full disassembly.
• Sensors and valves can be controlled by the plant PLC.
• Changeover, backwash, and pressure alarms can be automated.
• Can be connected to dissolving tanks, reactors, storage tanks, and filling machines.

Working Principle

The working principle of the stainless steel duplex filter is physical particle separation with continuous flow switching.

1. Liquid fertilizer is pumped from the dissolving tank, reactor, or fermentation tank.
2. The three-way valve directs flow into one filter housing.
3. The liquid passes through the filter bag or basket, which traps particles and suspended solids.
4. Clean liquid exits the housing and continues to storage or filling.
5. As particles collect, the pressure differential across the filter increases.
6. The operator or PLC switches flow to the second housing.
7. The loaded housing is cleaned, the media is replaced if needed, and it returns to service.

For multi-stage systems, the solution passes through a coarse filter first and a fine filter second. This extends media life and gives the final product a more consistent clarity.

Application in a Liquid Fertilizer Production Line

The duplex filter protects the final product and downstream equipment:

Dissolving tank -> High speed disperser -> Reactor or fermentation tank -> Stainless steel duplex filter -> Storage tank -> Filling machine

In this configuration:

• The duplex filter removes undissolved salts and impurities after reaction.
• It prevents particles from clogging filling valves, nozzles, and drip emitters.
• It protects spray and fertigation equipment used by the customer.
• It improves product clarity, stability, and shelf life.

LANE supplies the duplex filter as a single unit or as part of a complete liquid fertilizer production line with dissolving, reaction, storage, filling, and CIP systems.

Application Scope

• Water-soluble NPK fertilizers and mother liquors.
• Liquid NPK and NK fertilizer blends.
• Foliar fertilizers and fertigation concentrates.
• Chelated micronutrient solutions.
• Suspension fertilizers with controlled particle size.
• Organic liquid fertilizers and biofertilizers after fermentation.
• Any liquid fertilizer applied through drip or spray equipment.

Technical Specifications

The table shows standard configurations. LANE confirms capacity, filter precision, housing material, and automation level with the actual product before delivery.

Quality, Standards, and Certification

LANE manufactures stainless steel duplex filters under an ISO 9001 quality management system and can supply CE-certified equipment with material certificates for stainless steel housings and filter components.

For pressure-rated filter housings, the design can follow customer-specified codes including ASME Section VIII, PED, or GB/T 150. Hydrostatic testing and third-party inspection by SGS or BV are available.

For liquid fertilizer products exported to the European Union, the final product must meet Regulation (EU) 2019/1009. The duplex filter supports contaminant control and product consistency, and we recommend independent certification of the final product by the relevant authority.

Why Choose LANE Machinery

Henan Lane Heavy Industry Machinery Technology Co., Ltd. is a fertilizer equipment manufacturer with more than 20 years of engineering experience. LANE has delivered equipment and production lines to clients in more than 50 countries and supplied machines for a 100,000 tons per year national fertilizer project in Africa.

LANE provides one-stop service from filter selection and process design to overseas installation, commissioning, operator training, remote video guidance, and after-sales support. For liquid fertilizer projects, our engineers review the particle size, solids content, viscosity, and flow rate, then recommend the correct filter type, mesh, housing material, and automation level.

Frequently Asked Questions

Why does liquid fertilizer need a duplex filter?

Undissolved salts, suspended solids, and fermentation residues can clog drippers, spray nozzles, filling valves, and pumps. A duplex filter removes these particles and improves product clarity and consistency.

What is the difference between a duplex filter and a single filter?

A single filter must be stopped for cleaning. A duplex filter has two housings and a three-way valve, so production continues while one housing is cleaned or serviced.

What materials can the filter housing use?

SS304 is suitable for many water-soluble fertilizer products. SS316L is recommended for chloride, acid, and aggressive fertilizer chemistry.

How often does the filter need cleaning?

Cleaning frequency depends on the solids content of the product. Pressure gauges and differential pressure monitoring show when the filter is loaded. The duplex design allows cleaning without stopping production.

Can the filter handle suspension fertilizers?

Yes, with the correct filter grade. Suspension products need a filter that removes oversize particles without removing the intended suspended solids. LANE confirms the mesh and product requirement before delivery.

Can filtration be automated?

Yes. Pressure sensors, valves, and changeover can be controlled by the PLC, and optional automatic backwash reduces manual handling.

What is the difference between a duplex filter and a centrifugal separator?

A duplex filter removes particles by physical straining through a bag or basket. A centrifugal separator uses high-speed rotation to remove fine solids from lower-viscosity liquids. Some lines use both: a centrifugal separator first, then a duplex filter for final polishing.

What is the warranty?

LANE provides a five-year warranty, spare parts support, and overseas installation and commissioning services.

Get a Quote for Your Stainless Steel Duplex Filter

Tell LANE your product type, flow rate, particle size, solids content, and line configuration. Our engineering team will recommend the correct filter model, mesh, housing material, and automation level, then provide a technical data sheet and quotation.