What are the differences between diaphragms and membrane in diaphragm – seal pressure transmitters?

1.Introduction

In diaphragm-seal pressure transmitters, the diaphragm and membrane are two critical but functionally distinct components. Below is a clear comparison of their differences:

2.Core Differences at a Glance

3.Detailed Functional Analysis

3.1Diaphragm

3.1.1Role

Acts as a “safety barrier” for media isolation.

3.1.2Working Principle

Media pressure → Diaphragm deformation → Transmits pressure via fill fluid (e.g., silicone oil) to the internal membrane.

3.1.3Design Features

Smooth surface, anti-adhesion (e.g., PTFE coating against crystallization).

Corrugated structure enhances sensitivity (e.g., flat diaphragms for high-pressure resistance in oil/gas).

3.2Membrane

3.2.1Role

Serves as the “nerve center” for pressure sensing.

3.2.2Working Principle

Fill fluid pressure → Membrane micro-deformation → Piezoresistive/capacitive change → Electrical signal output.

3.2.3Design Features

Ultra-thin (e.g., 20µm silicon membrane) for high sensitivity.

Integrated Wheatstone bridge or capacitive plates (e.g., MEMS technology).

4.Collaborative Workflow

[Media] → Diaphragm deformation → Fill fluid transfers pressure → Membrane micro-deformation → Sensor signal output

4.1Diaphragm

Protects the membrane from corrosion, clogging, or overpressure.

4.2Membrane

Ensures high-precision signal conversion.

5.Key Selection Criteria

6.Application-Specific Requirements

7.FAQ

Q: Does diaphragm damage affect the membrane?

A: Yes. A ruptured diaphragm may cause fill fluid leakage, exposing the membrane to corrosive media (requires immediate shutdown).

Q: Can the diaphragm be omitted, using only the membrane?

A: No. Membranes are typically not media-resistant; diaphragms are essential for long-term stability.

8.Summary

The diaphragm is the “shield,” isolating media and transferring pressure.

The membrane is the “heart,” converting pressure to electrical signals.

BCST Group, as a leading manufacturer of pressure measurement solutions, specializes in producing high-quality diaphragm-seal pressure transmitters with robust diaphragm and membrane designs for harsh industrial applications.

Both components are indispensable. BCST’s expertise ensures optimal material selection and structural design based on media properties and pressure range, delivering reliable performance in critical processes.

8.1BCST Value Proposition

✔ Customized diaphragm materials (Hastelloy, Tantalum, etc.)  

✔ Advanced MEMS membrane technology for precision  

✔ Global certifications (ATEX, IECEx, SIL)  

✔ 24/7 technical support for industrial applications  

For tailored solutions, contact BCST Group’s engineering team.