WIKA 432.50 Stainless Steel Diaphragm Pressure Gauge

Overview

The WIKA 432.50 is a diaphragm pressure gauge for the process industry, manufactured to EN 837-3 with a stainless steel case and stainless steel wetted parts. A large, circular corrugated diaphragm clamped between two flanges gives the instrument a big working surface, so it reads low pressures from 0–16 mbar reliably and tolerates overpressure far better than a Bourdon tube gauge. WIKA positions the WIKA 432.50 for the chemical, petrochemical, oil and gas and power industries, as well as water and wastewater and general plant construction.

Seven Star LLC supplies the WIKA 432.50, its liquid-filled version 433.50 and the safety-pattern models 432.30 and 433.30 to customers in the Sultanate of Oman and the wider GCC, with engineering support in Muscat. Our team helps match the diaphragm material, lining and flange to the medium so that one gauge replaces a separate seal and Bourdon gauge in many low-pressure applications.

Measuring Principle

In the WIKA 432.50 the process pressure acts on one side of the diaphragm element inside the media chamber. The diaphragm deflects, and a link transmits the movement to the stainless steel movement and pointer. Because the element is clamped around its circumference and has a relatively large actuating force, WIKA notes that diaphragm systems are less sensitive to vibration than Bourdon tubes, which is a useful property on blowers, fans and pumps.

Overload protection comes from load take-up points: when pressure exceeds the range, the diaphragm comes up against the upper measuring flange and supports itself. As standard the WIKA 432.50 withstands 5 times full scale, and an optional version withstands 10 times full scale, in both cases up to a maximum of 40 bar. WIKA gives the example of a 0–4 bar gauge with 10-fold protection, which can see a short-term 40 bar overpressure without affecting accuracy. An open connecting flange avoids blocked pressure ports with viscous or crystallising media, and an extra flushing bore lets the chamber be cleaned.

Engineering Design of the WIKA 432.50

The case is stainless steel 1.4301 (304) or 1.4571 (316Ti) in nominal size 100 or 160 mm, with laminated safety glass or polycarbonate windows. The WIKA 432.50 and 433.50 meet safety level S1 per EN 837-1 with a blow-out device, while the 432.30 and 433.30 versions meet S3 with a solid baffle wall and blow-out back. The 433 variants are filled with glycerine-water mixture or silicone oil M50 and include a compensating valve, giving IP65; standard ingress protection is IP54, with a hermetically sealed IP66 option.

The diaphragm is 316L for spans up to 0.25 bar and NiCr alloy (Inconel) for spans from 0.4 bar, with the lower measuring flange in 316L. For extremely corrosive media the diaphragm alone, or the diaphragm and lower flange together, can be coated or lined with PTFE, Hastelloy, Monel, tantalum or gold (gold for the diaphragm only), sealed with FPM/FKM or PTFE; lined versions are class 2.5. Connections include G ½ B and M20 x 1.5 per EN 837, ½ NPT, and open connecting flanges such as 1 inch or 2 inch class 150 RF, 1 inch class 300 RF, or DN 25 and DN 50 PN 40.

Key Features

These datasheet points explain where the WIKA 432.50 outperforms a Bourdon gauge.

• Low scale ranges start at 0–16 mbar, making the gauge suitable for tank blanketing, vent headers and low-pressure gas.
• Standard 5-fold overload safety, optionally 10-fold, up to 40 bar protects the instrument from pressure spikes and test pressures.
• Stainless steel case and wetted parts resist aggressive media and corrosive outdoor environments.
• Open connecting flanges with optional flushing bore handle viscous, contaminated and crystallising media without blockage.
• A wide choice of linings, including PTFE, Hastelloy, Monel and tantalum, extends use to strong acids and chlorides.
• Accuracy class 1.6 as standard, with class 1.0 possible after a feasibility test, and a temperature error of 0.8% per 10 °C.
• Vacuum-resistant versions to −1 bar and compound ranges such as −1 to +1.5 bar are available.
• A QR code on the dial links to serial number, order number and certificates for each instrument.

Industrial Applications

Typical WIKA 432.50 duties in Oman include nitrogen blanketing on storage tanks at terminals in Mina Al Fahal and Sohar, flare and vent header monitoring, low-pressure fuel gas to burners, chemical dosing and chlorination skids at desalination plants, and slurry or sludge lines in wastewater treatment. The diaphragm design also suits polymer, resin and caustic service in petrochemical units where a Bourdon tube would clog or corrode.

When pressure ranges are higher and media are clean, a Bourdon gauge such as the WIKA 232.50 Stainless Steel Bourdon Tube Pressure Gauge remains the economical option, and for high working pressures with a separate seal the WIKA 990.27 Diaphragm Seal can be combined with a standard gauge. For low differential pressure across filters, the WIKA 732.51 Stainless Steel Differential Pressure Gauge uses a related diaphragm principle. Seven Star LLC supplies the WIKA 432.50 with engineering support, and our engineers in Muscat can review media compatibility before ordering for any site in Oman or the GCC.

Technical Specifications

The WIKA 432.50 data below is summarised from WIKA data sheet PM 04.03.

Related Versions

WIKA also builds the same diaphragm system with switch contacts as models PGS43.100 and PGS43.160, and with an electrical output signal as models PGT43.100 and PGT43.160, plus an Ex h version for hazardous areas. If your project needs local indication plus an alarm or a 4–20 mA signal from the same tapping, ask us about these variants of the WIKA 432.50 family.

How to Order

Send Seven Star LLC the range, overload requirement, nominal size, connection or flange rating, diaphragm material or lining and filling, and we will quote the WIKA 432.50 from our Muscat office. The WIKA data sheet PM 04.03 can be downloaded from this page, and our instrumentation engineers support projects across Oman and the GCC.