PRM-I250 Compact-Series is proud to present the in-Line Process Refractometer High Resulution model. This inline refractometer is perfect for all applications where a measuring needs to be as precise as Chemical, Petrochemical, Chemical fibre. The IPRM-G series is unrivaled in accuracy.



Product model


Measurement item

Refractive Index (nD), Brix, ,temperature.

Measuring range

0.0 – 25.0% Brix


0.1 Brix

Measurement accuracy

± 0.20 Brix

Brix range

Temperature corrected 5-50°C

Process temperature

5°C up to +50°C



Wetted parts

Stainless Steel SUS 316L;pp-gf30

Power supply

24 V DC


1 output 4 – 20 mA,1 serial output RS485

International Protection class

IP65 Water resistant

Process pressure

Max. 0.2 MPa, 2 bar

Dimensions and weight

Length400 x diam.112mm; approx. 700g

Cleaning components Options


Special scale

It is widely used in the online automatic detection of the concentration of metal working fluids such as cutting fluid, emulsion, quenching fluid, and wire drawing fluid. Mainly used for processing liquid tanks, tank installations, etc.


Measurement Principles
The refraction of light is a phenomenon wherein the direction that light is traveling changes as it passes through different mediums.
Through this phenomenon, we can observe as light’s direction changes and the “bent” appearance of substances even in the seemingly familiar, ordinary places in our day to day lives.
For example, imagine the lens of a pair of glasses and a pool.
When looking through the lens, an object appears larger or smaller than it is in reality.
When standing inside a pool, as you peer downward from the water’s surface, your legs will look shorter than they actually are.
As light moves from medium A (in this case, air) to medium B (lens and the pool’s water), it refracts.
Furthermore, it is known that light’s refraction changes depending on the concentration of a liquid.
The refractive index, which is a value that expresses the degree of refraction, is proportional to the density (mixture ratio) of a component.
Therefore, if there is 10g of sugar contained in 100ml of an aqueous solution and 20g of sugar contained in 100ml of an aqueous solution, the latter will have a higher refractive index value.
This difference in refractive index due to concentration variance has also been confirmed in solutions other than sucrose.
The properties of both the phenomenon known as the refraction of light and differing refractive index depending on concentration, are used as the principles of refractometers.
In addition to measuring the refractive index of a liquid, refractometers also display the concentration, converted from the refractive index.

Application highlights
Chemical, petrochemical, chemical fibre
Semiconductor, electronics industry
Mechanical processing, mining industry
Pharmaceutical industry
Food and beverage industry
Sugar, starch, sweeteners
Biofuels and fermentation industry
Electricity, energy industry

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