Rotameter Introduction

The rotameter (also known as the float flow meter or rotor flow meter) is an instrument that measures the volume flow of a fluid by moving a float up and down in a vertical tapered tube as the flow changes. It has a simple and intuitive structure and is widely used in industrial process control, laboratories and other fields. According to different materials, it is mainly divided into three types: metal, glass and plastic. The three types are described from different perspectives below.

Metal Tube Rotameter

• Material

Usually made of metal materials such as stainless steel (304/316), Hastelloy, etc., with a strong structure.

• Measuring Medium

Liquid: water, oil, corrosive liquid (corrosion-resistant material is required).

Gas: air, steam, inert gas, etc.

• Temperature Range

-80℃ ~ +400℃ (high temperature requires special design)

• Pressure Range

Excellent high pressure performance, up to 10~16 MPa.

• Others

Vibration and shock resistant, suitable for complex industrial environments.

Can be equipped with remote transmitter to achieve automatic control.

Non-transparent, flow rate display requires magnetic coupling or pointer.

Applications: Petrochemical, high temperature steam, high pressure gas pipelines.

Glass Tube Rotameter

• Material

High borosilicate glass tube, heat-resistant and pressure- resistant, transparent and visible.

• Measuring Medium

Liquids: Water, weak acid/alkaline solutions (chemical compatibility required).

Gas: non-corrosive gases such as air and nitrogen.

Not Applicable: Hydrofluoric acid, strong alkaline liquid (corrosive to glass).

• Temperature Range

-20℃ ~ +120℃ (sudden temperature change may cause cracking)

• Pressure Range

Low pressure, generally ≤1.6 MPa.

• Others

Transparent tube allows direct reading without the need for additional sensors.

Fragile, avoid mechanical shock and severe vibration.

Not suitable for use in environments with strong sunlight or ultraviolet rays (easy to age).

Applications: Laboratory, medicine, low-corrosive fluid monitoring.

Plastic Tube Rotameter

• Material

PP (polypropylene), PVC (polyvinyl chloride), PTFE (polytetrafluoroethylene), etc.

• Measuring Medium

Liquid: strong acid, strong alkali, organic solvent (select according to the material).

Gas: corrosive gases (such as chlorine).

• Temperature Range

-10℃ ~ +80℃ (PTFE up to 150℃)

• Pressure Range

Low pressure, generally ≤1.0 MPa.

• Others

Excellent corrosion resistance, but low mechanical strength and easy to age.

Lightweight and low-cost, suitable for one-time or short-term usage.

Avoid direct sunlight (UV rays accelerate the degradation of plastic).

Applications: Chemical laboratories, environmental water treatment, corrosive media measurement.