■ CDS.921, All st. steel Flush Diaphragm Seal

• All stainless steel body & diaphragm
• Flush diaphragm seal (direct / capillary type)
• Nominal pressure up to 400 bar
• Various filling liquids (Glycerin / Silicon / Vegetable oil, etc available)
• Cooling device & capillary connection [option]

 

■ Product Overview

The CDS.921 series is a flush diaphragm seal designed to protect pressure measuring instruments by isolating them from process media.
All wetted parts are made of stainless steel 316L, providing excellent corrosion resistance and making it suitable for hygienic applications such as food & beverage, pharmaceutical, and biotechnology industries, as well as aggressive chemical environments.
It can be assembled with pressure gauges (MAX, MBX series) or pressure transmitters (EDA.370, EDA.371), effectively preventing direct contact between process media and measuring instruments, thereby extending service life and ensuring stable performance.
With various system filling options and capillary connection configurations, CDS.921 can be optimized for high temperature, vacuum, viscous, and corrosive applications.

 

■ Measuring Principle

The CDS.921 diaphragm seal uses a thin metallic flush diaphragm to transmit pressure from the process media to the measuring instrument.
The process pressure deflects the diaphragm, and this movement is transmitted through the internal filling liquid to the pressure gauge or transmitter, either directly or via a capillary.
This design ensures accurate pressure transmission while protecting the measuring device from harsh process conditions such as high temperature, corrosion, or contamination.

 

■ Materials of wetted parts

All wetted parts are made of stainless steel 316L, ensuring high resistance to corrosion in most industrial applications.
Optional materials such as Teflon coating or special alloys are available for highly aggressive or specialized environments.

 

■ Accuracy class

CDS.921 does not define accuracy by itself, as it is a diaphragm seal. The overall accuracy depends on the connected measuring instrument.

▶ Pressure Gauge

• MAX series: Class 1.0 / 1.6 (EN 837-1)
• MBX series: Class 1.0 / 1.6 (EN 837-1)

▶ Pressure Transmitter

• EDA.370 / EDA.371: Class 1.0 F.S

 

 

■ Configuration & Options

▶ Direct mounting
▶ Capillary connection
▶ Cooling device (200℃ / 300℃)
▶ Various filling liquids (Glycerin, Silicon, Vegetable oil, etc.)
▶ Teflon coated diaphragm [option]
▶ Oil-free (Oxygen service) [option]

 

■ Application Industries

The CDS.921 diaphragm seal is widely used to protect pressure measuring devices in various industrial environments:
▶ Food & Beverage industry
▶ Pharmaceutical & Biotechnology industry
▶ Chemical & Petrochemical industry
▶ Semiconductor & Electronics industry
▶ Vacuum & negative pressure applications
▶ Oxygen service (oil & grease free)
▶ Water & wastewater treatment

 

■ Key Features

▶Complete isolation of measuring instrument from process media

▶Suitable for high temperature, corrosive, and viscous fluids

▶Compatible with various pressure gauges and transmitters

▶Ideal for hygienic and clean process applications

▶Reliable pressure transmission with enhanced equipment protection

 

■  General Technical Specifications

Pressure ranges Nominal pressure	-1…0 to 400 bar PN 400
Temperature resistance	Max. +250℃ (with cooling device option up to 300℃)
Process connection	Screw-in thread (DIN 3852) Diaphragm type Flush diaphragm (stainless steel 316L)
Filling liquid	Glycerin / Silicon / Vegetable oil / High temp oil
Mounting type	Direct / Capillary / Cooling device