Brand: Georg Fischer

GF Signet 3-2551 Magmeter Insertion Electromagnetic Flow Sensor

Name: GF Signet 3-2551 Magmeter Flow Sensor – Datasheet & Quote
Brand: Georg Fischer

Description

Overview

GF Signet 3-2551 Magmeter is an insertion-style electromagnetic flow sensor built with no moving parts, engineered for long-term reliability with minimal maintenance in chemical, water, and industrial process applications. Manufactured in wetted material combinations of polypropylene with 316L stainless steel, PVDF with Hastelloy-C, or PVDF with Titanium, the 3-2551 installs quickly into GF’s comprehensive line of flow fittings and delivers accurate, repeatable flow measurement across an exceptionally wide pipe size range of DN15 to DN900 (½ inch to 36 inches).

With engineering support in Muscat, Seven Star LLC supplies the GF Signet 3-2551 Magmeter and the complete GF Signet instrumentation range to water treatment plants, chemical processors, and industrial facilities across Oman and the wider GCC. Engineers and procurement teams in Muscat, Sohar, and Salalah rely on Seven Star LLC for genuine GF Signet flow sensors backed by manufacturer documentation, calibration support, and local technical guidance for fitting and range selection.

Measurement Principle

The GF Signet 3-2551 operates on Faraday’s law of electromagnetic induction: as conductive liquid flows past the sensor’s electrodes, a magnetic field generated within the sensor body induces a voltage proportional to the fluid’s velocity. This voltage signal is processed by the sensor electronics into a flow-rate output, requiring only that the process fluid meet a minimum conductivity of 20 µS/cm and that the pipe run full at the point of measurement. Because the electromagnetic method does not depend on differential pressure or a rotating element, the 3-2551 measures flow with a linearity of ±1% of reading plus 0.01 m/s and repeatability of ±0.5% of reading at 25°C across a velocity range of 0.05 to 10 m/s.

With no moving parts in the flow stream, the sensor is immune to wear from abrasive or fibrous media and avoids the fouling and mechanical failure modes common to paddlewheel and turbine sensors. The practical consequences are significant for plant operators: there is no pressure drop across the measurement point, no rotor to jam or wear out, and no recalibration drift from bearing degradation. The 3-2551 also includes empty pipe detection, which forces a zero-flow output whenever the electrodes are not fully wetted, preventing false readings during pipe draining or air-entrainment events.

Engineering Design of the GF Signet 3-2551

The GF Signet 3-2551 sensor body is available in three sensor types matched to pipe size: -X0 for ½ to 4 inch (DN15 to DN100), -X1 for 5 to 8 inch (DN125 to DN200), and -X2 for 10 to 36 inch (DN250 to DN900) pipe, each engineered for automatic alignment and insertion depth when installed with a GF Signet installation fitting. The enclosure carries a NEMA 4X / IP65 protection rating with a PBT case and polyamide display window, suitable for outdoor and washdown environments, and the sensor terminates in a 4-terminal connector accepting 16 to 22 AWG conductors for power and signal wiring.

Electrical output is selectable between a traditional 2-wire 4-20 mA passive loop (2551-XX-12, requiring 24 VDC ±10% external loop power), or a frequency/digital (S3L) output (2551-XX-11) compatible with GF Signet’s 8900, 9900, 9900-1BC, and 9950 flow instruments. A directional arrow on the sensor body must point downstream for correct operation, and the yellow housing can be reversed to orient the cable ports for the installation geometry, with a supplied liquid-tight connector sealing the cable entry against moisture ingress. The optional display version adds a 2×16 character LCD with permanent and resettable totalizers and up to three relay outputs for local alarm or control functions.

Key Features

Specifying the GF Signet 3-2551 for a project means choosing a Magmeter that combines a proven electromagnetic sensing principle with corrosion-resistant construction suited to demanding chemical and water applications:

No moving parts in the wetted flow path, eliminating mechanical wear, jamming, and the recalibration drift typical of paddlewheel and turbine flow sensors.
Wide pipe size coverage from DN15 to DN900 (½ inch to 36 inches) using a single sensor family across three body sizes.
Corrosion-resistant wetted materials in polypropylene/316L stainless steel, PVDF/Hastelloy-C, or PVDF/Titanium for compatibility with aggressive chemical and saline media.
Empty pipe detection that automatically forces a zero-flow output when the electrodes are not fully wetted, preventing false readings.
Bi-directional flow measurement with selectable 4-20 mA, frequency, or digital (S3L) output for direct integration into PLC, SCADA, or GF Signet flow instrumentation.
NEMA 4X / IP65-rated enclosure suitable for outdoor and washdown industrial environments without additional protective housings.
Linearity of ±1% of reading and repeatability of ±0.5% of reading at 25°C, providing dependable accuracy for billing, dosing, and process control applications.
Optional multi-language LCD display with permanent and resettable totalizers, supporting English, Spanish, German, French, Italian, and Portuguese menus.

Industrial Applications

The GF Signet 3-2551 Magmeter is widely deployed across chemical processing, water and wastewater treatment, desalination pretreatment, HVAC chilled water loops, and industrial water distribution networks where accurate, low-maintenance flow measurement is essential to plant operation. The GF Signet 3-2551’s corrosion-resistant wetted materials also make it a preferred choice for chemical dosing skids, scrubber control systems, neutralization processes, and commercial pool and aquarium filtration monitoring, where debris and aggressive cleaning chemicals would quickly foul a mechanical flow sensor.

Backed by manufacturer datasheet documentation, Seven Star LLC distributes the 3-2551 Magmeter to municipal utilities, industrial water treatment operators, and process plants throughout the Sultanate of Oman and the broader GCC, including the growing industrial and desalination infrastructure around Sohar and Salalah. Local technical support for fitting selection, K-factor configuration, and calibration data, combined with genuine GF Signet documentation, makes Seven Star LLC the practical regional source for plant engineers specifying reliable electromagnetic flow measurement.

Technical Specifications

Engineers comparing the GF Signet 3-2551 against other insertion sensors can reference the table below, which summarizes the key technical parameters of the GF Signet 3-2551 Magmeter insertion flow sensor:

Parameter	Specification
Model	GF Signet 3-2551 Magmeter
Sensor type	Insertion-style electromagnetic flow sensor
Pipe size range	DN15 to DN900 (½ in. to 36 in.)
Flow velocity range	0.05 to 10 m/s (0.15 to 33 ft/s)
Linearity	±1% of reading plus 0.01 m/s
Repeatability	±0.5% of reading @ 25°C (77°F)
Minimum conductivity	20 µS/cm
Wetted materials	PP/316L SS, PVDF/Titanium, or PVDF/Hastelloy-C
Output options	4-20 mA loop, Frequency, or Digital (S3L)
Power requirements (4-20 mA)	21.6 to 26.4 VDC, 22.1 mA max.
Enclosure rating	NEMA 4X / IP65 (with cap installed)
Operating temperature (media)	0°C to 85°C (32°F to 185°F)
Maximum operating pressure	10.3 bar @ 25°C (150 psi @ 77°F)
Approvals	CE, FCC, UL/CUL, NSF (PP versions), RoHS compliant

Request a Quote for GF Signet 3-2551 Magmeter Insertion Electromagnetic Flow Sensor

Plant engineers and procurement teams across Oman and the GCC can request a formal quotation for the GF Signet 3-2551 Magmeter directly from Seven Star LLC, with fitting selection support, technical datasheets, and calibration data provided alongside every order. Working closely with plant engineers in the region, Seven Star LLC supplies on request and supports custom sensor body, output, and display configurations for water and process flow measurement projects. Contact the Seven Star LLC instrumentation division today to discuss your electromagnetic flow measurement requirements and receive a competitive, locally supported quotation.

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About brand

Georg Fischer (GF) is a Swiss industrial group founded in 1802, when Johann Conrad Fischer bought a mill near Schaffhausen and turned it into a foundry. In 1864 his grandson Georg Fischer began making malleable iron fittings, introducing the GF fish trademark, and piping is one of the company's oldest businesses. GF Piping Systems makes plastic and metal piping systems, valves and Signet flow and water quality instruments.

Seven Star LLC, an independent supplier in Oman, lists the GF Signet 3-2551 Magmeter insertion electromagnetic flow sensor and the GF Signet 8550-1 flow transmitter.

Georg Fischer company profile

Founded	1802, Schaffhausen, Switzerland
Founder	Johann Conrad Fischer
Headquarters	Schaffhausen, Switzerland
Piping business	Fittings since 1864
Product families	Type 546 ball valves, Type 567 butterfly valves, Signet flow sensors and transmitters, thermoplastic pipes and fittings

Milestones

1802: Johann Conrad Fischer founds the company.
1864: GF begins making malleable iron fittings.

GF Signet instruments listed here

The 3-2551 Magmeter is an insertion flow sensor: it is mounted through a fitting in the pipe wall, has no moving parts and needs a liquid with some electrical conductivity. The 8550-1 is a flow transmitter that takes the signal from a Signet flow sensor and provides a display and outputs for the control system. Sensor, pipe fitting and transmitter are chosen together, because the fitting sets the insertion depth for a given pipe size and material.

Georg Fischer products we list

Family	Examples
Flowmeters	GF Signet 3-2551 Magmeter Insertion Elec…, GF Signet 8550-1 Flow Transmitter
Ball Valves	GF Type 546 Pro Linear Thermoplastic Bal…
Butterfly Valves	GF Type 567 Wafer Thermoplastic Butterfl…

Ordering GF Signet parts: what we need

Copy the manufacturer part number from the label, which normally starts with 3- followed by the model and option digits. Add pipe size, pipe material, the fitting you have, the fluid and its conductivity, sensor body material, output required and cable length. Water treatment, desalination and chemical dosing sites in the GCC often have older Signet transmitters; if a model is no longer produced we ask for the manufacturer's current replacement, which for the 8550 is listed by distributors as the Signet 9900.

Facts checked against the Historical Dictionary of Switzerland and GF histories, October 2026.

Browse Georg Fischer products by category: Flowmeters.

Frequently Asked Questions

What is the main advantage of the GF Signet 3-2551 over paddlewheel flow sensors?

The 3-2551 has no moving parts in the flow stream, so it avoids the wear, jamming, and fouling that paddlewheel and turbine sensors experience with debris-laden or chemically aggressive fluids, resulting in lower maintenance and longer service life.

Does installing the 3-2551 require significant downtime or pipe modification?

No. The sensor installs quickly into GF Signet insertion fittings such as tees, saddles, and weldolets, and can typically be inserted into a pressurized system using a hot-tap fitting, minimizing process downtime compared to inline flowmeter replacement.

What pipe sizes and wetted materials are available?

The 3-2551 covers pipe sizes from DN15 to DN900 (½ inch to 36 inches) using three sensor body sizes, with wetted material options of polypropylene/316L stainless steel, PVDF/Titanium, or PVDF/Hastelloy-C to match the chemical compatibility of the process fluid.

Can the 3-2551 be integrated with existing SCADA or PLC systems?

Yes, the sensor offers a 4-20 mA loop output compatible with any PLC, SCADA, or chart recorder, as well as a frequency or digital (S3L) output for direct connection to GF Signet 8900, 9900, and 9950 flow instruments.

Is Seven Star LLC an experienced supply partner for Georg Fischer products?

Yes, Seven Star LLC is an experienced supplier of Georg Fischer and GF Signet instrumentation in Oman and the GCC, supplying genuine products with technical support and calibration documentation.

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