WIKA 990.27 Diaphragm Seal

Overview

WIKA 990.27 is a diaphragm seal with flange connection engineered to protect pressure measuring instruments from aggressive, adhesive, crystallising, corrosive, highly viscous, or hot process media. Featuring a flange with a flush welded diaphragm, the WIKA 990.27 is mounted in place of a blind flange and is designed to fit all commonly used standard flanges, making it the preferred solution across chemical, petrochemical, and general process industries wherever the process medium itself would otherwise damage a direct-mount pressure gauge or transmitter.

As the official authorized partner and exclusive regional representative for WIKA, Seven Star LLC proudly supplies the WIKA 990.27 diaphragm seal to chemical, petrochemical, and oil and gas customers across Oman and the wider GCC. Every unit shipped through Seven Star LLC is genuine WIKA product with full manufacturer warranty and access to local technical support – ensuring facility engineers and procurement teams in Muscat, Sohar, and Salalah receive an authentic, factory-certified WIKA 990.27 backed by regional service.

Working Principle

The WIKA 990.27 operates by physically isolating the pressure measuring instrument from the process medium. A flush-welded diaphragm, mounted flat against the flange face, contacts the process fluid directly, while the space behind the diaphragm and the connected instrument is filled with a system fill fluid. As process pressure acts on the diaphragm, it flexes slightly and transmits that pressure through the incompressible fill fluid to the pressure gauge, switch, or transmitter mounted on the seal, giving an accurate reading without the wetted internals of the measuring instrument ever contacting the aggressive process fluid.

This isolation principle gives the WIKA 990.27 its defining protective advantage: because the flush diaphragm design has no crevices, pockets, or dead spaces where product can collect, it resists clogging from highly viscous or crystallising media, and the diaphragm and sealing face can be manufactured from corrosion-resistant alloys selected specifically for the process fluid in question. Assembly to the measuring instrument can be made via a direct connection, through a cooling element for high-temperature media, or via a flexible capillary for remote-mounted instrumentation.

Engineering Design of the WIKA 990.27

The WIKA 990.27 is available in a wide variety of dimensions following common industry flange standards and nominal widths, and is suitable for all currently used standard flanges, so it can be installed in place of a blind flange without custom fabrication. The upper body and wetted parts (diaphragm and sealing face) can be manufactured from identical or different materials depending on the application, and the diaphragm and sealing face are also available with special coatings for additional chemical or abrasion resistance where a solid alloy alone is insufficient.

A cell-type design variant is also available for applications requiring a sandwich-flange configuration with a contoured diaphragm bed. System fill fluids are selected to match the process temperature range and the specific pressure instrument connected, and the diaphragm seal system as a whole can be configured for hazardous area installations per the relevant ATEX or IECEx documentation, giving engineers a fully certified, application-matched protective barrier between instrument and process.

Key Features

The WIKA 990.27 combines flexible material selection with a proven flush-diaphragm design that makes it a standard choice for protecting pressure instruments from difficult process media.

• A flange with flush welded diaphragm eliminates dead spaces where crystallising or highly viscous media could otherwise collect.
• Available for all commonly used standard flanges and nominal widths, allowing installation in place of a blind flange.
• The upper body and wetted parts can be manufactured from identical or different materials to match specific chemical compatibility needs.
• Optional diaphragm and sealing face coatings extend chemical and abrasion resistance beyond the base alloy.
• Assembly options include direct connection, cooling element for high-temperature media, or flexible capillary for remote mounting.
• A cell-type sandwich-flange variant with a contoured diaphragm bed is available for specialized installations.
• System fill fluids are selected to match process temperature and the connected pressure instrument.
• Suitable for hazardous area installations per applicable ATEX/IECEx documentation.

Industrial Applications

The WIKA 990.27 is deployed across the chemical process industry, petrochemical industry, and general process and machine building sectors wherever aggressive, highly viscous, crystallising, or hot media would otherwise damage an unprotected pressure gauge or transmitter. Typical duties include reactor and vessel pressure protection, slurry and polymer process lines, and high-temperature process pressure measurement requiring a cooling element.

As the officially authorized partner for WIKA, Seven Star LLC distributes the WIKA 990.27 to refineries, petrochemical complexes, and chemical processing facilities throughout Oman and the GCC. The diaphragm seal is a strong fit for process pressure protection across the Sohar and Salalah petrochemical zones, as well as for chemical and oil and gas facilities across Muscat that require dependable isolation of pressure instruments from harsh process media.

Technical Specifications

The table below summarizes the core specifications of the WIKA 990.27 diaphragm seal as supplied by Seven Star LLC.

Call To Action

Seven Star LLC supports the full procurement cycle for the WIKA 990.27 diaphragm seal, from formal RFQ submission to regional warehouse stock availability, technical datasheet delivery, and direct consultation with our instrumentation division on flange size, material selection, and fill fluid for your process application. As the authorized partner for WIKA in Oman and the GCC, we ensure every WIKA 990.27 diaphragm seal is delivered with full manufacturer warranty and dependable local technical support. Contact Seven Star LLC today to request a quotation or discuss your diaphragm seal requirements.