Metal Tube Rotameter

Metal Tube Rotameter is a Variable Area Flow Meter used for measuring fluid and gas flow in industrial pipelines where glass tube rotameters cannot be used.

This meter has a tough construction of metallic tubes, having a float inside the tube, which changes position depending on the flow rate and creates balance between the buoyant force and weight of the float.

Rotameters have a magnetic coupling device, which conveys the motion of the float to the indicator outside of the meter.

Due to the durable stainless steel body of this meter, it can be used for process applications under high pressure and temperature conditions.

• Suitable for high-pressure and high-temperature applications.
• Linear flow reading with output signal options.
• All stainless steel construction for strength and durability.
• Compact design with short stroke.
• Minimum pressure drop across the meter.
• Magnetic coupling mechanism ensures smooth and stable indication.
• Optional thermal insulation or steam tracing jacket.
• Suitable for liquid and gas flow measurement across process industries.

• Fluid: Liquids & Gases
• Specific Gravity: Up to 2.95
• Viscosity: Up to 200 cP
• Design Temperature: Up to 350°C
• Design Pressure: Up to 100 Kg/cm²
• Measuring Range: 10 to 60000 LPH (Liquids), 3.3 to 1400 Nm³/hr (Air/Gas)

Fluid Entry into the Rotameter Vertically

Metal Tube Rotameter is mounted vertically and allows the process fluid to enter the rotameter from the lower end and then flows upwards in the measuring tube that is conical in shape.

Movement of the Float and Balancing Forces

When the process fluid enters the tube, it acts upon the float and creates an upward force on it. The float rises and stops at a certain point when the upward force created by the fluid flow equals the weight of the float.

Variable Area Flow Meter

This float travels up and down the tapered metal tube having increasing cross-sectional areas with increasing flow rate in the meter. It is a variable area flow meter because the position of the float varies according to the flow rate.

Magnetic Coupling for Readings

As the metal tube does not permit direct visualization of the float movement, the float movement is transferred magnetically to the external pointer through a magnetic coupling mechanism.

Size Configurations

• Line Sizing Range: ½“ up to 4″ NB

Material Options

• Body Construction Metals: Stainless Steel 304, Stainless Steel 316, Stainless Steel 316L
• Corrosive Liner Integration: PTFE lined on SS for aggressive process chemicals

End Connections

• Flanged Options: Built to match ASA, BS, or DIN standard dimensions
• Sanitary Option: Standard Triclover clamp interface
• Screwed Options: Male or Female (M/F) BSP or NPT threaded interfaces

Operating Parameters & Range Limits

• Liquid Capacity Span: 10 to 60,000 LPH of Liquid
• Air/Gas Capacity Span: 3.3 to 1400 Nm³/hr of Air/Gas at NTP
• Maximum Design Temperature: Up to 350°C
• Maximum Design Pressure: Up to 100 Kg/cm²
• Fluid Viscosity Barrier: Up to 200 centipoise
• Fluid Specific Gravity Threshold: Up to 2.95
• System Measurement Accuracy: ±2% of FSD (Full Scale Deflection)

Enclosure & Tracking Features

• Protection Class: Weatherproof housing design
• Physical Accessories: Available with thermal insulation or tracing steam jacket arrangement
• Flow Trajectory Designs: Vertical upward flow or horizontal right-to-left / left-to-right process streams

Fluid Entry Vertically: The fluid entry of the Metal Tube Rotameter happens vertically, where the flow is directed from the bottom inlet into the measuring tube that rises upwards. Vertical orientation enables the float to travel up and down depending on the fluid conditions.

Float Motion: With the upward fluid motion, an upward force is applied on the float present in the tube by the fluid, and hence, it is lifted due to this motion against the gravitational force. The float will move according to the rate of the flow, hence making it a variable area flow meter.

Balance of Forces: The float moves up until the upward forces of flow and buoyancy are balanced by the gravitational force. This is the point where the float becomes static and stays at one point in the tapered measuring tube.

Magnetic Coupling for Flow Measurement: Due to the opaque nature of the metal tube, there is no way you can see the float movement. Therefore, a magnet is used for transferring float movement to the external indicator via the magnetic coupling method.