Composite Diaphragm

Product Features

1. Material Systems
Composite diaphragms are available in a range of elastomer base materials selectable by service condition: NBR (nitrile) for petroleum-based oils and fuels, service temperature -30°C to +90°C; FKM (fluoroelastomer) for high-temperature (up to +200°C) and aggressive chemical environments; EPDM for water, steam, and outdoor weathering, service temperature -57°C to +176°C; CR (chloroprene) offering balanced oil, weather, and refrigerant resistance; VMQ (silicone) for extreme temperature range from -100°C to +300°C with FDA-compliant grades available. Multi-layer construction allows combination of different materials within a single diaphragm.

2. Reinforcement Construction
Fabric reinforcement layers (nylon, polyester, fiberglass, or aramid) are embedded within or between elastomer layers, carrying tensile loads, providing dimensional stability, and preventing crack propagation under pressure pulsations and repeated flexing. Reinforcement enables the diaphragm to withstand higher working pressures while maintaining flexibility in the flex zone. Fabric type and weave pattern are selected based on pressure rating and stroke requirements.

3. Surface Coating
PTFE (Teflon®) coating can be applied to the media-wetted side, forming a continuous chemical barrier with exceptional resistance to aggressive media including acids, alkalis, and solvents. The PTFE layer is bonded to an elastomeric backing that provides flexibility and return force. This construction resolves the inherent limitations of PTFE—poor elasticity and insufficient recovery—while leveraging its chemical inertness.

4. Flex Zone Design
The flex zone (convolution or deformation area) of the diaphragm is specifically engineered to minimize stress concentration. By reducing thickness in this region or optimizing the geometric transition, fatigue accumulation per million cycles is significantly reduced, extending service life under reciprocating motion.

5. Mounting Configurations

Available mounting configurations include:

Peripheral Bead Fixing: The outer bead of the diaphragm is clamped by bolts or flanges. The center region responds to pressure with flexing motion. Suitable for standard actuators and control valves.

Threaded Insert Fixing: A metal threaded insert is embedded at the diaphragm center, providing a threaded connection to the actuating rod for secure, non-loosening attachment. Suitable for high-frequency or long-stroke applications.

Clamped (Unbonded) Fixing: Both the outer periphery and center of the diaphragm are clamped by flanges. Motion is achieved through the diaphragm's own elastic deformation. Suitable for precision control applications with space constraints or special sealing requirements.

6. Dimensions & Tolerances
Standard products range from 5 mm to 1000 mm in diameter, with thickness from 0.4 mm to 3.94 mm. Die-cutting and molding processes support any geometry, with critical dimensional tolerances held to ±0.005 inches (±0.13 mm).

Product Specifications

Application

● Pneumatic & Hydraulic Actuators
Diaphragm-actuated control valves, pressure regulators, and positioners – requiring precise stroke response and low hysteresis.

● Diaphragm Pumps
Chemical metering pumps, air-operated double-diaphragm pumps, and vacuum pumps – demanding chemical resistance and high-cycle flex life.

● Automotive & Engine Systems
Carburetors, fuel pumps, EGR valves, and turbocharger wastegate actuators – requiring oil/fuel resistance and temperature stability.

● Gas Control Equipment
LPG/methane gas actuators, regulators, and flow metering devices – requiring gas impermeability and consistent low-pressure response.

● Pharmaceutical & Bioprocessing
Sterile fluid handling, metering pumps, and hygienic valve applications – requiring FDA/USP Class VI compliance and steam-in-place compatibility.

● Water Treatment & HVAC
Chemical feed pumps, backflow preventers, and control valves – requiring EPDM's water/steam resistance and ozone stability.

● Oil & Gas
Wellhead control valves, pipeline actuators, and chemical injection pumps – requiring FKM/PTFE's resistance to sour gas, hydrocarbons, and high temperatures.

Advantages

1. Multi-Layer Synergy
Chemical barrier, fabric reinforcement, and elastomeric return layers each serve a distinct function, delivering performance that exceeds any single-material solution.

2. Reinforced Durability
Embedded fabric prevents crack propagation and stretch deformation, maintaining dimensional stability under pressure pulsations and high-stroke conditions.

3. Extended Flex Life
Reduced-thickness flex zone design minimizes stress concentration, significantly extending cycle life compared to solid elastomer diaphragms.

4. Broad Chemical Compatibility
PTFE facing resists aggressive media; FKM/EPDM backings provide secondary chemical defense, covering a wider range of service conditions.

5. Precision Control
Low spring rate, zero breakaway friction, and constant effective area ensure consistent force-stroke characteristics for high-accuracy control.

6. Flexible Customization
Diameters from 5 mm to 1000 mm, with multiple fabric/elastomer combinations available. Custom geometries supported without extensive tooling investment.

Manufacturing Standards

FAQ