RK1650 Series is a completely renewed model of existing KOFLOC RK1600R with sophisticated design to fit sophisticated laboratory or plant equipment.

Variable area flow meters operate at a constant delta pressure (Δp) and the area changes with the flowrate. The area will increase as the flowrate through the meter increases to preserve a constant Delta Pressure (Δp).

The most common design of variable area meter is the cone-and-float type, which is also known as a rotameter. The basic design of a variable area meter is a tapered tube (usually glass) containing a self-centring float that is pushed up by the flow and pulled down by gravity.

At higher flow rates the float rises to increase the area between the tube and the float and maintain a constant Δp.

Features RK1650 Series

A compact flowmeter with variations of total length of 84 mm, 104 mm, 124 mm and 154 mm for choice according to the user’s needs
・Low pressure loss
Pressure loss minimized to allow applications for low supply pressure
・Choice of needle valve to suit the user’s needs
Four types of needle valve available for your choice according to the requirement of supply pressure
・Superior stability
All tubes are precision-formed to provide the float with outstanding repeatability and stability.
A flowmeter at quite affordable price achieved through our all-out effort at streamlined design


・For environmental instrumentation systems
・For general instruments for analysis
・For purge systems
・For semiconductor manufacturing equipment

Standard Specifications

Fluids Air, N2, O2, H2, He, Ar, and CO2 (Calibration by actual gas)
For other gases, consultation is necessary regarding whether
conversion conditions or calibration by actual gas is to be used.
Flow range (Full scale) 1L, 2L, 3L, 5L, 10L, 15L, 20L/MIN
Accuracy FS±5% (Measurement point)
Proof pressure 0.8 MPa for 5 L/MIN or less
0.5 MPa for 10 L/MIN or more
Available scale 10:1
Materials S BS
Body block and some
other components
SUS304, SUS303 Brass
Tapered tube Pyrex®, glass
Packing FKM NBR
Float Pyrex, SUS316, glass
Protective cover Acrylic resin
(Temperature resistance) MAX60℃
Connection Rc1/8 (Standard); Rc1/4 (Optional)