Product Core Brief

• Model: A413331
• Brand: Metso / Neles (Valmet Automation)
• Series: Mini low-flow OEM air pretreatment accessory for ND9000 series intelligent valve positioners
• Status: Active production original spare part, new surplus & factory refurbished stock available
• Core Function: Supply clean, stabilized low-volume instrument air to small 0.1–1 dm³ linear/rotary actuators paired with ND9102HX miniature positioners; remove moisture, oil and solid contaminants while maintaining steady output pressure to eliminate small valve hunting and positioning drift
• Product Type: Integrated miniature coalescing filter + precision low-flow pressure regulator combo unit
• Key Specs: 1.4–10 bar input air; adjustable output 0–8 bar; G1/4 internal threads; 5μm stainless coalescing filter; built-in mini pressure gauge; IP65 compact aluminum housing; lower flow than A413139; NAMUR NE107 direct mount; Condition: New Original Surplus / Refurbished

Product Introduction

The Metso is the smallest-size filter regulator in Metso’s OEM air accessory lineup, purpose-built exclusively for tiny low-volume actuators (0.1–1 dm³) used with ND9102HX miniature intrinsically safe positioners. It is widely deployed on small bypass valves, sampling valves and small pulp/paper machine auxiliary control valves with limited air consumption demand.Its compact internal spool design delivers matched low volumetric air throughput, perfectly sized to avoid overshoot on small actuator strokes that would occur with larger A413139/A413337 high-flow models. The integrated 5μm coalescing stainless filter removes compressor oil, condensed water and pipeline scale, protecting the miniature pilot valve inside ND9102HX from clogging and premature wear.This unit supports shared NAMUR bracket mounting alongside ND9102HX without extra pipe adapters, saving installation space on compact valve assemblies. OEM reliability testing records an MTBF of 142,000 operating hours under continuous industrial field ambient.

Key Technical Specifications

Quality Control Process (Engineer’s Perspective)

1. Incoming Verification: Cross serial batch codes against Metso original accessory production manifests to filter counterfeit aftermarket copies. Visually inspect compact aluminum housing casting integrity, mini gauge glass for scratches, port thread condition and drain valve sealing surfaces.
2. Live Functional Test: Supply stable 6 bar clean instrument air to the inlet port, sweep output pressure from 0 to 8 bar full range to validate gauge linearity. Run a 24-hour continuous low-flow soak cycle at standard 4 bar setpoint; record output pressure stability and condensate separation performance hourly.
3. Pneumatic Performance Test: Apply ±2 bar upstream supply fluctuation to test regulator lock stability; output pressure deviation limited to ≤0.05 bar. Verify full particle and moisture capture efficiency with standardized industrial contaminant test media.
4. Mechanical Compatibility Check: Mount to standard NAMUR bracket together with positioner, confirm no piping interference and perfect port alignment; inspect pressure adjustment knob operation for smooth, stick-free rotation.
5. Final QC & Packaging: Fit plastic dust caps to all threaded ports, place unit into original factory packaging. Attach dated QC Pass sticker listing pressure stability test results prior to warehouse storage.

Replacement Pitfall Guide

❗ Flow Model Mismatch Risk: Installing larger A413139/A413337 filter regulators on small 0.1–1 dm³ actuators will create severe valve overshoot and hunting; excessive air volume surges through tiny actuator chambers during small setpoint changes.❗ Incorrect Operating Pressure Setup Risk: Standard recommended setpoint for ND9000 series positioners is 4 bar. Output pressure above 6 bar causes violent small valve stroke overshoot; pressure below 2 bar results in slow movement and large positioning error. Do not exceed 4.8 bar under normal operation.❗ Condensate Drain Neglect Risk: The compact filter bowl accumulates condensed water during operation; weekly draining is mandatory. Overfilled condensate flows downstream into the positioner and corrodes internal miniature pilot valve components.❗ Thread Seal Application Error Risk: Only apply PTFE tape to external pipe threads; avoid introducing sealant debris into internal unit ports. Loose tape fragments block regulator small internal orifices and break pressure stabilization performance.❗ Mounting Orientation Restriction Risk: Install vertically with drain bowl pointing downward. Horizontal mounting disrupts gravity-driven condensate separation and invalidates filter water removal function.Keep these in mind and you’ll cut 90% of rework time.

Compatibility Matrix & Benchmarks

Compatibility Matrix

• miniature low-flow valve positioners → : Direct OEM Replacement — NAMUR shared bracket mount, zero adapter modification required
• Mini-volume Metso linear/rotary actuators 0.1–1 dm³ → : Fully matched low-flow air pretreatment accessory
• A413139 medium-flow filter regulator → : Needs Adaptation — Same mechanical mounting footprint, small actuator stroke tuning must be revalidated after downgrade
• ND9103HX / ND9104HX medium/large positioners (>1 dm³ actuators) → : Incompatible — Insufficient air flow capacity, causes slow valve stroke response and positioning deviation

Benchmarks

• Output pressure deviation under ±2 bar upstream supply swing: ≤ ±0.04 bar
• Dew point condensate separation efficiency: >99% for instrument air dew point above -20 °C
• Pressure loss across filter regulator at nominal 4 bar full flow: <0.10 bar