421 Flow Cup

Overview

The Model 421 Flow Cup is a viscometer conforming to JIS K 5600-2-2 and ISO 2431, used to measure the viscosity of paints, varnishes, lacquers, and similar coating materials. The Flow Cup consists of a stainless-steel container whose interior surface is finished to a roughness of 0.5 μm or less, together with an orifice embedded in the bottom of the container. The time taken for the sample filling the container to flow out through the orifice is measured, and the kinematic viscosity in mm²/s is then read from a graph relating kinematic viscosity to flow (efflux) time. The cup is supplied in No.3 and No.4 orifice sizes to cover different viscosity ranges.

Construction

The Flow Cup is machined from stainless steel with an interior surface finished to a roughness of 0.5 μm or less to ensure a controlled, repeatable flow of sample. An orifice of defined dimensions is embedded in the bottom of the container to meter the outflow of the sample.

Test Method and Standards

The container is filled with sample and the time for it to drain through the bottom orifice is measured with a stopwatch. This flow time is converted to a kinematic viscosity value in mm²/s using the reference graph specified in JIS K 5600-2-2 and ISO 2431, allowing results to be reported in standard viscosity units rather than as a simple comparative time.

Common Specifications

Model Comparison