KROHNE H250 M40 Variable Area Flowmeter
Overview
KROHNE H250 M40 is an all-metal variable area flowmeter engineered as a cost-effective, highly flexible all-rounder for liquid and gas flow measurement across the process and OEM industries. Building on a purely mechanical float measuring principle that KROHNE has refined since 1921, the KROHNE H250 M40 combines simple, auxiliary-power-free measurement with a modular indicator system that scales from basic local display up to full 4-20 mA HART and fieldbus integration, all without interrupting the running process to add or change modules.
With fast quotation turnaround and technical support, Seven Star LLC proudly supplies the KROHNE H250 M40 variable area flowmeter to industrial, OEM, and utility customers across Oman and the wider GCC. Every unit supplied through Seven Star LLC comes with manufacturer documentation and access to local technical support – helping facility engineers and procurement teams in Muscat, Sohar, and Salalah receive a correctly specified KROHNE H250 M40 instrument.
Measurement Principle
The KROHNE H250 M40 measures flow using the variable area (float) principle. Process fluid enters the bottom of a precision-machined metal measuring cone and lifts a float upward until the buoyancy force, the fluid’s form resistance, and the float’s weight reach equilibrium at a height on the cone proportional to flow rate. The float’s position is transmitted to the external indicator through a magnetic coupling, entirely isolating the electronics from the wetted process, and eliminating the need for any electrical penetration into the flow path itself.
This purely mechanical principle gives the KROHNE H250 M40 several practical advantages that matter in the field. Because measurement and local display are possible without any auxiliary power supply, the flowmeter provides a fail-safe, always-on visual indication in areas without instrument power, and because the sensing element has no electronics in the wetted path, it tolerates extreme pressure, temperature, and aggressive media that would compromise conventional electronic flow sensors. The float principle also naturally supports a wide measuring range span, standard 10:1 and extendable to a market-leading 100:1 turndown.
Engineering Design of the KROHNE H250 M40
The KROHNE H250 M40 uses a rugged, all-metal measuring cone available in a range of corrosion-resistant materials, rated to withstand demanding pressure, temperature, and product conditions. The modular M40 indicator can be configured with limit switches, a 2-wire 4-20 mA output, a totalizer with LCD and pulse output, or fieldbus interfaces such as HART, PROFIBUS PA, or FOUNDATION Fieldbus – and additional modules can be added or replaced in the field at any time without shutting down the process. NE 107-compliant device and application diagnostics, including Continuous Float Monitoring (CFM), flag issues such as a blocked or pulsating float before they become process problems.
The KROHNE H250 M40 is available in vertical, horizontal, and fall-pipe installation orientations to match the application layout, and is offered in a hygienic H250F variant built to FDA, EC1935, and GB4806 requirements for food and pharmaceutical service. SIL 2-certified variants are available for both the 4-20 mA output type and the limit switch type, supporting functional safety loops without a separate certified transmitter.
Key Features
The KROHNE H250 M40 delivers a rare combination of mechanical simplicity, modular electronics, and rugged construction, and it is precisely this combination that has made the KROHNE H250 M40 a standard reference across the variable area flowmeter market.
- Purely mechanical float measurement allows local flow indication without any auxiliary power supply.
- The modular M40 indicator supports limit switches, 4-20 mA output, totalizer with LCD, and HART, PROFIBUS PA, or FOUNDATION Fieldbus communication.
- Additional electronic modules can be added or replaced in the field at any time without interrupting the process.
- A standard 10:1 measuring range span is extendable to a market-leading 100:1 turndown, reducing the need for separate low-flow instrumentation.
- NE 107 diagnostics with Continuous Float Monitoring (CFM) detect blocked or pulsating float conditions before they affect process control.
- SIL 2-certified versions are available for both 4-20 mA (type B) and limit switch (type A) configurations.
- A hygienic H250F variant meets FDA, EC1935, and GB4806 requirements for food and pharmaceutical applications.
- The all-metal cone construction provides high resistance to pressure, temperature, and aggressive process media.
Industrial Applications
The KROHNE H250 M40 is deployed across general process industries, OEM equipment packages, food and pharmaceutical production, and utility applications wherever a reliable, low-maintenance flowmeter for clean gases, vapours, or liquids is required. Its wide material and configuration range makes it equally suited to compressed air monitoring, hydraulics flow, cooling water circuits, and demanding chemical or high-temperature process duties.
With engineering support in Muscat, Seven Star LLC distributes the KROHNE H250 M40 to industrial facilities, OEM panel builders, and utility operators throughout Oman and the GCC. The flowmeter is a strong fit for the process industries of Sohar and Salalah, as well as for food, pharmaceutical, and general manufacturing plants across Muscat that require dependable, auxiliary-power-free flow indication alongside optional digital integration.
Technical Specifications
The table below summarizes the core specifications of the KROHNE H250 M40 variable area flowmeter as supplied by Seven Star LLC.
| Parameter | Specification |
|---|---|
| Model | KROHNE H250 M40 |
| Measuring Principle | Variable area (float, magnetic coupling) |
| Measuring Range Span | 10:1 standard, 100:1 optional turndown |
| Process Temperature (Standard) | Up to +100°C / +212°F |
| Process Temperature (HT Variant) | -200°C to +400°C (-328°F to +752°F) |
| Process Pressure (Standard) | Up to 10 barg / 145 psig |
| Indicator Options | Limit switches, 4-20 mA (2-wire), totalizer with LCD, fieldbus |
| Communication | HART, PROFIBUS PA, FOUNDATION Fieldbus |
| Diagnostics | NE 107 device/application diagnostics with CFM (Continuous Float Monitoring) |
| Safety Certification | SIL 2 (type A limit switch, type B 4-20 mA) |
| Hygienic Variant | H250F – FDA, EC1935, GB4806 compliant |
| Typical Applications | General process, OEM, food & pharmaceutical, utilities |
Request a Quote for KROHNE H250 M40 Variable Area Flowmeter
Seven Star LLC supports the full procurement cycle for the KROHNE H250 M40 variable area flowmeter, from formal RFQ submission to availability and lead-time confirmation, technical datasheet delivery, and direct consultation with our instrumentation division on cone sizing, indicator configuration, and material selection for your application. We supply every KROHNE H250 M40 flowmeter on request with manufacturer documentation and dependable local technical support. Contact Seven Star LLC today to request a quotation or discuss your flow measurement project.
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- Datasheet KROHNE H250 M40 Variable Area Flowmeter Datasheet Download
KROHNE product families on this page
KROHNE names its instruments by measuring principle, which makes a tag list easy to read:- OPTIFLUX and WATERFLUX: electromagnetic flowmeters, such as OPTIFLUX 2300, OPTIFLUX 4300 and WATERFLUX 3070 for water networks
- OPTISONIC and ALTOSONIC: ultrasonic flowmeters, including the inline OPTISONIC 3400, the clamp-on OPTISONIC 6300, the OPTISONIC 7300 for gas and the ALTOSONIC V12 for custody transfer of gas
- OPTIMASS: Coriolis mass flowmeters such as OPTIMASS 1400 and 6400
- H250 M40 and DK800: variable area flowmeters
- OPTIWAVE and OPTIFLEX: radar and guided radar level transmitters
Where KROHNE flowmeters and level transmitters are used
Typical duties in the GCC are produced water and injection water metering, potable water and wastewater networks, fuel gas and sales gas measurement, chemical dosing, and tank level in terminals and process units. Coriolis meters cover mass flow and density on hydrocarbons, while electromagnetic meters need a conductive liquid.Ordering KROHNE instruments: what we need
Send the full type code and serial number from the nameplate, or a clear photo of it. For a new KROHNE flow meter we need line size and flange rating, liner and electrode material for electromagnetic types, fluid, flow range, pressure and temperature, power supply, output and protocol, and the hazardous area approval required. We check the code against KROHNE documentation before quoting and provide the manufacturer's datasheet and certificates on request.Browse KROHNE products by category: Flowmeters, Level Transmitter, Flow Computers.
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