The Riels Instruments LFE series is a digital electromagnetic flow switch/sensor designed for accurate and reliable flow measurement of water and non-corrosive conductive liquids. Unlike mechanical flow switches, the LFE series operates on Faraday's law of electromagnetic induction, featuring no moving parts or obstructions in the flow path. This results in an exceptionally low pressure drop (max 0.02 MPa) and minimal viscosity constraints, saving pumping energy and ensuring long-term reliability even in demanding industrial environments.

Principle of Operation

According to Faraday's law, when a conductive fluid passes through a magnetic field, an electromotive force (EMF) is induced. This EMF is directly proportional to the fluid velocity. The LFE sensor applies this principle by generating a magnetic field across the flow tube and measuring the induced voltage. This voltage is then converted into a volumetric flow rate signal, which can be output as a 4-20mA analog signal or a scaled pulse. The flow direction can be detected, and the output can be configured for forward or reverse flow monitoring.

Key Features

• No Moving Parts: Ensures maintenance-free operation and long service life, ideal for continuous duty in industrial processes.
• Low Pressure Drop: The unobstructed oval flow passage minimizes pressure loss, reducing pumping costs and improving system efficiency.
• Compact and Robust: Available in a compact remote version (without display) with C37 brass (standard) or 304 stainless steel wetted materials. IP65 rated for use in harsh environments.
• Flexible Installation: Can be installed in any orientation. The flow direction can be changed after installation without recalibration.
• Versatile Outputs: Provides a standard 4-20mA analog output and a pulse output for totalization. Options include 1-5V output.

Technical Specifications

• Media Compatibility: Water and non-corrosive conductive liquids (minimum conductivity required). Not suitable for deionized (distilled) water or oil.
• Flow Ranges: 0.5-20 L/min, 2.5-100 L/min, 5-200 L/min.
• Accuracy & Repeatability: ±4% of full scale (F.S.) accuracy, ±2% F.S. repeatability.
• Pressure Rating: Maximum operating pressure 10 bar (1 MPa).
• Temperature Rating: 0°C to 85°C (media).
• Port Sizes: 3/8", 1/2", 3/4", 1" Rc, NPT, or G threads.
• Output Options: 4-20mA analog output, pulse output.
• Power Supply: 12-24 VDC.
• Electrical Connection: M12 connector (remote version).
• Certifications: CE, RoHS compliant.

Applications

The LFE series is ideal for flow control and monitoring in a wide range of industrial applications, including:

• Cooling water monitoring for welding guns, metal molds, and industrial machinery.
• Flow control for water-soluble coolants in machining processes.
• Water treatment systems, pump protection, and leak detection.
• Industrial automation processes requiring precise flow monitoring without pressure loss.