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AD Series Iris Valve: A Choke Valve for Powder and Bulk Solids Handling

Created on 08.29
The XNFM AD series iris valve — also known as a choke valve — gives a compact, dust-tight shut-off for dry powders and granular materials in big bag discharge, bins, hoppers and chutes.
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What Is an Iris Valve / Choke Valve?

An iris valve, commonly called a choke valve, controls the flow of dry bulk solids by opening or closing a flexible fabric diaphragm. Unlike traditional gate or butterfly valves, the iris valve constricts the passageway from the center outward, allowing material to discharge evenly while forming a reliable dust seal.
The XNFM AD series iris valve is built with a stainless steel control ring, a metal handle with trigger lock, and a smooth actuator. The fitted fabric sleeve acts as both a product barrier and a dust seal, preventing powder from leaking into the atmosphere. This makes it especially popular in pneumatic conveying, big bag discharge stations and gravity-fed material handling systems.

How Does the XNFM AD Iris Valve Work?

The AD iris valve uses a dual-diaphragm arrangement for in-line applications. When the handle or actuator is turned, the control ring draws the diaphragm inward, reducing the bore from full open to fully closed. Because the closure starts at the center and moves outward, the material is discharged smoothly and uniformly — ideal for free-flowing powders that must not flood or hang up.
The rugged construction handles materials with densities up to 1600 kg/m³, making it suitable for medium to heavy duty bulk solids applications.
Figure 2. XNFM AD series iris valve — stainless steel control ring, fabric diaphragm, quick-release handle.
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AD Series Iris Valve Specifications

Item
Specification
Model
AD
Brand
XNFM
Nominal diameter
DN80 / 100 / 150 / 200 / 250 / 300 / 350 / 400 / 450 mm (3" ~ 18")
Body material
AISI 304 / AISI 316 / Aluminum alloy
Control ring / handle
Stainless steel with trigger lock
Diaphragm material
Nylon, Anti-static Nylon, Terylene, TPU, Cotton
Installation
Quick release clamp / flange
Packing
Wooden cases
Bulk density limit
Up to 1600 kg/m³
Operation
Manual handle, pneumatic or electric actuator (optional)
Origin
Zhejiang Wenzhou, China
Customization
Available on request

Diaphragm Material Selection

Choosing the right diaphragm material extends service life and maintains product quality. XNFM AD iris valves offer several fabric options to match your powder properties:
  • Nylon
  • Anti-static Nylon
  • Terylene
  • TPU
  • Cotton

Advantages of the XNFM AD Iris Valve

  • Cost-effective:
  • Compact and light:
  • Explosion-safe handling:
  • Unencumbered opening:
  • Center-closing action:
  • Field-adjustable diaphragm:
  • Dust-tight seal:

Application Limits

While the AD iris valve is versatile, it is not the right choice for every duty. Avoid using it where:
  • Very high throughputs or extremely frequent cycling are required.
  • The material is heavy, highly abrasive, or has large, sharp particles.
  • The system has excessive material flow velocity that would accelerate diaphragm wear.
  • The valve must support or lift other heavy downstream equipment.

Where the AD Iris Valve Is Used

The XNFM AD series iris valve is specifically designed for dry solids handling in:
  • Big bag / FIBC discharge stations
  • Gravity discharge from bins, hoppers and chutes
  • Intermediate bulk container (IBC) outlets
  • Feed control for pneumatic conveying lines
  • Dosing and batching stations
Main industries served include food, pharmaceuticals, minerals, petrochemicals, plastics and textiles — anywhere a clean, controlled discharge of dry powder or granules matters.

Product Video

AD380.mp4 1.65MB
Video 1. XNFM AD series iris valve operation and size overview.
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