Fabric-reinforced Diaphragm

1. What Is a Fabric-Reinforced Diaphragm? Core Functions

1) Definition

A fabric-reinforced diaphragm is a flexible functional component made by embedding one or more layers of woven fabric (such as nylon, polyester, or aramid) into a rubber matrix. It combines:

• Sealing and elasticity from rubber
• Strength, dimensional stability, and fatigue resistance from fabric reinforcement

2) Core Functions

• Sealing: Separates two media (gas / liquid / oil)
• Force and displacement transmission: Converts pressure changes into mechanical motion
• Fatigue-resistant deformation: Withstands long-term reciprocating motion without rupture

The essence of a fabric-reinforced diaphragm is:
“It must move, but not leak; it must be flexible, but not fail in tension.”

2. Working Principle of Fabric-Reinforced Diaphragms

Operating Mechanism

1) One side of the diaphragm is subjected to pneumatic or hydraulic pressure

2) The diaphragm undergoes axial or radial flexural deformation

3) Through the diaphragm center or attached components, it:

Ÿ   Pushes a valve stem

Ÿ   Drives an actuator

Ÿ   Isolates the working medium

Engineering Key Points

1) The diaphragm should bend, not stretch

2) The fabric layer carries the primary tensile stress

3) The rubber layer ensures sealing and protects the fabric

3. Common Structural Types of Fabric-Reinforced Diaphragms

1) Flat Diaphragm

·         Simple structure

·         Short stroke

·         Low cost

·         Used in low-displacement applications

2) Convoluted Diaphragm

·         Multiple convolutions

·         Higher displacement capability

·         More uniform stress distribution

·         Higher tooling and molding requirements

3) Rolling Diaphragm

·         Almost no tensile strain, primarily rolling deformation

·         Longest service life

·         Widely used in pneumatic cylinders and actuators

4. Rubber and Fabric Material Selection

1) Common Rubber Materials

2) Common Fabric Reinforcement Materials

Fabric orientation (warp/weft) and cutting angle directly affect diaphragm service life.

5. Key Performance Indicators of Fabric-Reinforced Diaphragms

1) Fatigue Life (Most Critical)

·         Reciprocating cycles: 10⁵ ~ 10⁷

·         Strongly influenced by:

a.          Structural design

b.          Fabric selection

c.           Rubber formulation

2) Burst Pressure

·         Typically ≥ 3–5 times the working pressure

3) Displacement and Response Sensitivity

·         Affects valve and actuator accuracy

4) Sealing Performance

• Micro-leakage or zero-leakage requirements

6. Typical Applications of Fabric-Reinforced Diaphragms

7. Common Failure Modes and Root Causes