WIKA 700.01 Magnetic Piston Differential Pressure Gauge

Overview

The WIKA 700.01 is a compact differential pressure gauge with a magnetic piston, designed to monitor differential pressure even when the line itself runs at high working pressure. WIKA lists filter systems, pump monitoring, cooling circuits and pipeline systems as its main applications, with the gas and air preparation and supply industry as the primary market. The system case is stainless steel, the indicator case is aluminium die-cast, and the standard instrument weighs only about 220 g, so it can hang directly on rigid impulse lines without a heavy support.

Seven Star LLC supplies the WIKA 700.01 and its sister model 700.02 with separating diaphragm to plant operators, OEM skid builders and maintenance contractors in Oman and across the GCC, with engineering support in Muscat. We help customers choose the right differential range, static pressure rating, connection layout and reed contact configuration for each filter or pump.

Measuring Principle

In the WIKA 700.01 the two pressures p1 and p2 act on the plus and minus sides of a measuring chamber that is divided by a pressure-loaded magnetic piston. The difference between the two pressures moves the piston axially against a measuring range spring made of stainless steel 1.4310. An annular magnet fixed to the pointer follows the magnet inside the piston, so every piston position corresponds to a defined pointer position on the dial.

The important consequence, as WIKA explains, is that the measuring system and the indicator are completely separated mechanically, with no shaft passing through the pressure boundary and therefore no leakage path to the outside. In the WIKA 700.01 the small volume flow from the plus side to the minus side is minimised by design and does not interfere with normal processes; for liquids or media with suspended solids WIKA specifies the model 700.02, whose separating diaphragm in NBR prevents any flow between the chambers.

Engineering Design of the WIKA 700.01

The measuring chamber is stainless steel 1.4571 with two G ¼ female connections in-line on the left and right side per EN 837-1, and other female or male threads, lower mount or back mount layouts and a fine filter in the plus connection can be specified. The piston is stainless steel 1.4571 with a hard ferrite magnet. Working pressure ratings of 100, 250 or 400 bar are offered, and overload safety on either side extends to the full maximum working pressure, so a blocked filter or a one-sided pressurisation during start-up will not damage the gauge.

The NS 80 aluminium dial is printed with an outer black bar scale and an inner red psi scale, and a maximum drag pointer is optional. The window is clear non-splintering plastic snapped into the case. Mounting can be by rigid measuring lines, a panel mounting flange (available only on the WIKA 700.01) or an instrument bracket for wall mounting. The system and indicator cases can be exchanged on site, which allows a range change or repair without replacing the complete instrument.

Key Features

The WIKA 700.01 offers the following advantages for differential pressure monitoring.

• Differential pressure ranges from 0–400 mbar to 0–10 bar suit filter, strainer and pump differential monitoring.
• Static pressure ratings of 100, 250 or 400 bar allow installation on high-pressure gas and compressed air lines.
• Overload safety on either side up to the maximum working pressure protects against one-sided pressurisation.
• The magnetic coupling separates measuring system and indication, eliminating leakage to the outside.
• Indication accuracy is ±3% of full scale value with increasing differential pressure.
• Up to two reed contacts, model 851.3 or 851.33, can be retrofitted and adjusted on site between 20 and 80% of full scale.
• Low weight of approximately 220 g and a compact NS 80 case simplify installation on skids.
• Ingress protection IP54, ambient temperature 0 to +60 °C and medium temperature up to +100 °C.

Industrial Applications

In Oman the WIKA 700.01 is well suited to compressed air dryer and filter trains, natural gas filter separators and fuel gas skids, instrument air packages, nitrogen generators and blower intake filters, all of which involve clean gas or air. Power stations and desalination plants use the liquid-rated 700.02 variant on cooling water and other liquid filters, and OEMs in Rusayl and Sohar fit them to packaged compressors where a contact signal for filter change is required.

For very low differential pressures in HVAC and clean rooms, the Dwyer Magnehelic 2000 Differential Pressure Gauge is usually the better instrument, and for larger dials with higher accuracy at high static pressure the WIKA 732.51 Stainless Steel Differential Pressure Gauge is an alternative. Where a 4–20 mA signal is needed alongside local indication, the WIKA DPGT43 Differential Pressure Gauge with Output Signal combines both functions. Seven Star LLC supplies the WIKA 700.01 with engineering support, and our team can supply matching manifolds and impulse fittings for installations across Oman and the GCC.

Technical Specifications

The WIKA 700.01 specifications below are taken from WIKA data sheet PM 07.14.

Installation Guidance

Mount the WIKA 700.01 according to the symbols on the case, with the plus connection to the high-pressure side upstream of the filter and the minus connection downstream. As general practice, fit a three-valve manifold so the gauge can be equalised and isolated during maintenance, and open the equalising valve first during start-up. Choose a range whose full scale is close to the filter change differential recommended by the filter manufacturer, and set any reed contact to that value so the control system receives a timely alarm.

How to Order

To receive a quotation for the WIKA 700.01, tell Seven Star LLC the differential range, static pressure rating, connection layout, mounting method and whether reed contacts or a drag pointer are required. Our Muscat office will check availability and lead time, share the WIKA data sheet PM 07.14 and provide engineering support for your filter and pump monitoring points in Oman and the GCC.