WIKA 732.51 Stainless Steel Differential Pressure Gauge

Overview

The WIKA 732.51 is a differential pressure gauge for the process industry, made of highly corrosion-resistant stainless steel and fitted with an all-metal, all-welded media chamber. Because there are no elastomer sealing elements between the chambers and the atmosphere, the gauge maintains long-term leak tightness on aggressive gases and liquids. It measures differential pressure spans from 0 to 16 mbar up to 0 to 40 bar, and it withstands high static operating pressure and high overload of up to 40 bar, which makes it a standard choice for filter, pump and level monitoring.

Seven Star LLC supplies the WIKA 732.51 to oil and gas operators, refineries, desalination and water treatment plants, and HVAC contractors across Oman and the GCC, with engineering support in Muscat. A local differential pressure reading tells an operator at a glance when a filter needs changing or a pump has lost head, without opening a control system screen.

Measurement Principle

The plus and minus media chambers of the WIKA 732.51 are separated by a diaphragm element, and metal bellows isolate both chambers from the atmosphere. The difference between the two pressures deflects the diaphragm axially, and a link carries this deflection to the stainless steel movement, which turns it into pointer rotation. Diaphragm elements have a relatively large actuating force and, because of their annular clamping, they are less sensitive to vibration than Bourdon tubes.

Overload protection comes from metallic load take-up points: when one side sees a much higher pressure, the diaphragm rests against a matching metal seat, so the element can tolerate up to 10 times its full scale value, to a maximum of 40 bar. The influence of static pressure on the reading is ±0.04 % per bar for spans above 0.25 bar and ±0.3 % per bar for the smallest spans, and the temperature error is no more than ±0.5 % of full scale per 10 °C.

Engineering Design of the WIKA 732.51

The case is stainless steel 304 or 316Ti with a safety level S1 design to EN 837-1, including a blow-out device, and a laminated safety glass or polycarbonate window. The model is unfilled and has an adjustable pointer for zero setting. Wetted media chambers, process connections, venting and bellows are stainless steel 316Ti; the diaphragm is 316Ti for spans up to 0.25 bar and nickel-chromium alloy (Inconel) for spans of 0.4 bar and above. Spans up to 0.25 bar include venting of the media chambers, which is optional on larger spans.

Process connections are lower mount, as 2 x G 1/4 female, 2 x G 1/2 B male, 2 x 1/4 NPT female or 2 x 1/2 NPT male, with side positions on request. Nominal size is 100 or 160 mm, with single or dual scales and special scales such as square root for flow indication across an orifice. The WIKA 732.51 is built to EN 837-3 and DIN 16003, and further versions include oil- and grease-free, oxygen, hydrogen and silicone-free builds, plus ATEX Ex h approval for hazardous areas.

Key Features

The WIKA 732.51 is engineered for long, leak-tight service on demanding media:

• All-metal, all-welded media chamber without elastomer seals for long-term leak tightness.
• Differential pressure spans from 0-16 mbar to 0-40 bar, plus vacuum and +/- ranges.
• Overload safety and static pressure up to 40 bar, depending on span.
• Diaphragm measuring element with metallic load take-up points, less sensitive to vibration than a Bourdon tube.
• Accuracy class 1.0, 1.6 or 2.5, selected at order.
• Medium temperature options up to +150 °C and ambient -20 to +60 °C.
• Ingress protection IP54, IP65 or IP66.
• QR code on the dial linking to serial number, order number and certificates.

Industrial Applications

In oil and gas production and processing in Oman, the WIKA 732.51 is used across cartridge and coalescer filters, strainers on pump suction lines, and gas filter separators, where a rising differential pressure signals a blocked element. Its high static pressure rating allows it to sit on lines operating at tens of bar while reading only a few hundred millibar of differential. On closed vessels and tanks, it can also indicate liquid level by measuring the hydrostatic head between a bottom and a top connection.

Desalination and water treatment plants along the coast, from Barka to Sur, use differential pressure gauges across multimedia filters, cartridge filters and RO pre-treatment stages. In district cooling plants and large HVAC systems, the WIKA 732.51 shows the pressure drop across strainers, chillers and heat exchangers, helping operators schedule cleaning before flow suffers. Seven Star LLC supplies the gauge with the span, static rating and accessories required, together with the WIKA data sheet.

For single-point pressure readings in the same material, see the WIKA 232.50 stainless steel pressure gauge.

Technical Specifications

Specifications for the WIKA 732.51 are taken from WIKA data sheet PM 07.05 (02/2025):

How to Order

When requesting a WIKA 732.51 quotation from Seven Star LLC, include the differential pressure span, the maximum static line pressure, the medium and its temperature, the connection type and whether a valve manifold is needed. Our Muscat team will confirm the configuration, check delivery options for Oman and the GCC, and send the WIKA data sheet with the offer. If a 4-20 mA signal or a switch output is also needed, compare the WIKA DPGT43 differential pressure gauge with output signal, the Yokogawa EJA110E differential pressure transmitter and the CCS 646DZE differential pressure switch.