DFY-R5000 RAM Filter

In the textile industry, Fiber Bed Mist Eliminators installed at the stack outlets of stenter (ramöz) machines are high-efficiency industrial solutions designed to capture airborne oil mist, blue smoke and sub-micron particulates.

1. Operating Principle

Unlike conventional mechanical filters, fiber bed eliminators rely on Brownian diffusion. As the contaminated gas passes through a dense bed of fine glass or synthetic fibers, three distinct mechanisms take place:

• Capture: Oil droplets as small as 0.1 micron impact and adhere to the fibers.
• Coalescence: Captured droplets merge into larger drops that drain to the bottom of the bed under gravity.
• Self-Cleaning: Because the collected oil is liquid and runs off continuously, the bed does not blind unless solid dust is present.

2. Main Components & Construction

The systems are typically modular and built for long service life:

• Fiber Bed: Engineered-density mat made of fiberglass, polypropylene or polyester.
• Support Cage: Stainless steel or corrosion-resistant alloy support structure.
• Drainage System: Collection sump where the recovered oil is drained off or routed to recovery.

Key Advantages

• Blue Smoke Elimination: Fully removes the visible plume from the stack.
• Fire Safety: Prevents oil build-up in ductwork, minimizing fire risk.
• Low Energy Consumption: Uses significantly less power than electrostatic systems.
• Long Service Life: No moving parts, so the risk of mechanical failure is very low.

3. Comparison Analysis

This document is for information purposes only. Engineering approval is required for application details.

Efficiency & Typical Performance

The DUCON fiber-bed RAM filter uses deep-bed microfiber media for sub-micron aerosol control. It delivers high efficiency in the 0.1–3 µm range, offers low initial ΔP, and provides a long service life. This is a patented design developed by DUCON specifically for RAM machines and differentiated from competitors. While optimized for RAM applications, it also performs successfully across a broad range of processes.

• Efficiency: 95–99.95% (0.1–3 µm)

• Initial ΔP: 150–700 Pa

• Typical outlet: < 5–20 mg/Nm³

Superior Filter Performance

System elements are validated for maximum performance through shop and field testing. With proper cooling and face velocity, stack opacity drops to 5% or below; near-zero opacity is targeted in most processes. The test methodology is defined during design and verified on site with conditioning and acceptance criteria.

Operating Principle

As the gas stream passes through the fiber bed, multiple capture mechanisms act simultaneously. After coalescence, enlarged droplets drain. To extend the life of the final filter, a pre-filter is used, and hot gases are cooled by a high-pressure Venturi scrubber. The pre-Venturi scrubber provides effective pre-separation of particulates as well as gas cooling.

Capture Mechanisms

• Inertial Impaction: ≈ 4 µm and larger particles impact fibers due to inertia and are captured.

• Interception: 1–3 µm particles follow streamlines and are intercepted on fiber surfaces.

• Brownian Diffusion: Sub-micron (< 1 µm) particles reach fibers via random motion; coalesced droplets then drain.

Cooling Methods

• Cyclonic Washer: Reduces exhaust temperature by adiabatic cooling (water evaporation); return water is distributed onto a cyclonic tray to help wash out solids.

• Ambient-Air Dilution Cooling: Dilution with ambient air; regulated via a damper or a temperature controller.

• Air-to-Air Heat Exchangers: Counter-flow heat exchange between clean air and hot process exhaust with proper condensate control.

Easy Maintenance

Emission-control systems that clean exhaust from RAM machine stacks will foul over time and therefore require maintenance. Thanks to DUCON’s careful design, the required maintenance is significantly reduced. When maintenance is needed, accessibility is a key design attribute.

• Access doors: Doors on the upper and lower sections of the unit provide safe, fast entry to the system.

• Steam connections: Steam ports at the top and bottom of the vessel can be used for steam quenching/dewaxing and for cleaning the filters—especially useful when waxy compounds are present.

• Sloped-to-drain floor: The unit base is sloped toward a drain to facilitate removal of solids that may settle in the hopper.

• Pre-filter service: The pre-filter is cleanable and can be removed via the access door for thorough cleaning.

• Replacement filters: Supplied installation-ready (pre-packed); no repacking is required.

• Side service covers: Convenient side covers provide access to the filter elements; no lifting equipment is required for filter maintenance.

Sequence of Operation

The exhaust gas first enters the cooling stage. Cooling is critical because it condenses most organics and promotes coalescence of sub-micron particles.

1. Adiabatic cooling (cyclonic tray washer):Cooling is performed adiabatically on a fixed cyclonic tray using water as the medium. The cyclonic washer uses turbulent air motion to create aggressive air–water contact and also removes a portion of larger particulates from the exhaust stream.

2. Water recirculation and makeup:Cooling water is stored in an integrated tank within the system. To minimize consumption, water is recirculated, and automatic makeup compensates for evaporation losses.

3. Pre-filtration (droplet/particle removal):As the cooled air exits the wash tray, it enters the pre-filter. In addition to contaminants, most water droplets are removed, which lowers the differential pressure across the fiber-bed filters and protects them from sticky surface loading. As the medium loads, ΔP rises; a Photohelic® differen

Why Choose the DUCON® DFY-RF5000 RAM Filter?

The DUCON® DFY-RF5000 RAM Mist Collector Systems deliver state-of-the-art technology aimed at boosting your profitability. Whether you operate a single line or multiple plants, DUCON provides the optimum solution.

The Nature of Textile Emissions

In textile production, process exhaust from RAM (stenter) ovens naturally produces visible “smoke” or blue haze due to the evaporation of light fractions (hydrocarbons). As these vapors condense, they form sub-micron aerosols that are inherently difficult to capture with conventional filters.

Limits of Conventional Approaches

• Dry dust filters: Designed for dry particulate, they do not drain recovered mist well, often causing frequent media changes.

• Electrostatic precipitators (ESPs): Surfaces foul quickly, driving maintenance cost and downtime; under unfavorable conditions they can also pose a potential fire hazard.

• Wet scrubbers alone: When used as a stand-alone solution on RAM exhaust, they may not consistently achieve the required final clarity/opacity control at high mist loads.

DUCON® Solution: DFY-RF5000 Fiber-Bed System

• High efficiency, low ΔP: Excellent collection in the 0.1–3 µm range with low initial pressure drop and long service life.

• Integrated architecture: Cyclonic adiabatic cooling + indexing pre-filter + fiber-bed coalescing stage for effective sub-micron aerosol removal.

• Reduced maintenance: Indexing pre-filter lowers sticky load; fiber-bed drainage minimizes surface loading and extends maintenance intervals.

• Scalability: Modular design for single-line or multi-line plants; straightforward retrofit into existing lines.

• Compliance ready: Headroom to meet increasingly stringent air-quality requirements over the coming years.

Bottom Line

Thanks to the combination of high efficiency and low maintenance cost, DUCON® RAM Mist Collector Systems are the preferred method for controlling textile production emissions. By advancing fiber-bed filtration to a new level, DUCON helps ensure your systems will continue to meet tightening air-quality standards for years to come.