The FK-LZ-B Metal Tube Rotameter is a variable area flow measurement instrument widely used in industrial automation and process control systems. It is characterized by compact structure, wide measuring range, easy installation and operation.
This flow meter is suitable for measuring the flow rate of liquids, gases and steam, especially for low flow rates and small pipe diameters. Due to its excellent reliability and cost-performance ratio, it has been widely used in petrochemical, power, metallurgy, food, pharmaceutical and water treatment industries for many years.
The instrument consists of a sensor and an indicator, supporting local display and electrical signal output for industrial control integration.
Suitable for Small Diameter & Low Flow Applications
Ideal for low velocity media and small pipeline flow measurement.
Wide Range Ratio (10:1)
Provides stable measurement across a broad operating range.
All-Metal Construction
Designed for high temperature, high pressure and corrosive media.
Non-Contact Magnetic Coupling Transmission
Ensures reliable signal transfer without mechanical wear.
Dual-Line LCD Display with Backlight
Displays instantaneous flow rate and cumulative flow simultaneously.
4–20mA Remote Transmission Output
Supports integration with PLC, DCS and industrial control systems.
Upper & Lower Limit Relay Alarm (Two-Wire System)
Enables process alarm and safety control functions.
Multiple Power Supply Options
DC, AC or battery-powered versions available.
Data Recovery & Backup Function
Includes power loss protection and data retention capability.
Low Maintenance & Long Service Life
No complex internal moving mechanisms; reliable long-term operation.
Low Straight Pipe Requirement
Minimal installation constraints compared to other flow measurement devices.
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Why Choose This Metal Tube Rotameter
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Proven variable area flow measurement technology
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Suitable for harsh industrial environments
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Excellent performance-price ratio
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Easy installation and low maintenance
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Reliable solution for low flow measurement
The FK-LZ-B operates based on the variable area flow measurement principle.
Inside a vertical conical measuring tube, a movable float is installed. When fluid flows upward through the tapered tube:
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The float rises due to fluid force.
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The float position increases with increasing flow rate.
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The annular area between the float and cone tube changes accordingly.
When the flow rate reaches a constant value (Q), the float remains in dynamic equilibrium at a certain height (h). At this point:
reach equilibrium.
According to Bernoulli’s equation, force balance principles, and fluid continuity laws, the instantaneous flow rate can be calculated from the annular area between the float and the cone tube.
Inside the float, a high-performance permanent magnet is embedded. The magnetic field allows the float position to be transmitted to the external indicator through non-contact magnetic coupling.
The indicator converts the float displacement into:
The FK-LZ-B Metal Tube Rotameter is widely used in industrial process flow measurement, including:
Petrochemical Industry
Power & Energy Industry
Metallurgy & Steel Industry
Food & Beverage Industry
Pharmaceutical Industry
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Process liquid control
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Gas supply systems
Water Treatment
Its ability to measure liquid, gas and steam makes it a versatile solution for industrial automation systems.
