The Hydro-Mix is a rugged, flush mounted microwave moisture measurement sensor for mixers and conveyors in process control environments. Designed by Hydronix to be installed in the turbulent environment of a mixer, the Hydro-Mix features integral signal processing and is easily connected to any control system. The sensor measures at 25 times per second which enables rapid response to any changes in moisture content, including the determination of homogeneity.

The Hydro-Mix sensor offers a choice of measurement modes for optimising the sensor performance for sand, aggregates, concrete and other similar materials. The sensor is designed to be fitted flush within a mixer, screw conveyor or in a chute. For conveyor belt applications, the Hydro-Mix sensor is installed using the Hydro-Skid pantograph arm enabling the sensor to ride over the surface of the flowing material.

Quick Overview

The Hydro-Mix digital microwave moisture sensor is designed for use with all types of mixers. Either it is a pan type, planetary or a twin shaft mixer, the sensor is flush mounted in the base or the walls of it, not impeding the progress of the material as it moves through processing.

Moisture measuring inside the mixer of a concrete production plant for cementitious and precast products is completely mandatory, given that controlling and checking the moisture levels of the final product is perhaps the most important factor as far as quality assurance and raw materials saving is concerned. The fact is that every mixing in the precast industry is not eligible for any additional treatment after leaving the mixer. It goes directly to the molds of the products and if the amount of water is not correct then, in the best case scenario, this results in to defective products.

Hydro-Mix can be used in order to automatically control the moisture in each batch mixed inside a mixer with a possible error of ± 0,1%.


  • The sensor’s body is made of stainless steel, its protection ring is made of hardened steel and its faceplate is made of ceramic.
  • The sensor incorporates all electronical circuits without the need of any outer device apart from the power supply.
  • Two analogue outputs and digital RS485 communications and configurable digital inputs / output make the sensor simple to integrate into a control system.


  • Steady production quality that does not depend on the operator’s skills
  • Reduced cement consumption
  • Reduced waste and cost due to rejecting products as a result of a mistaken moisture value, consistency or homogenization.
  • Increased productivity due to being able to calculate the ideal mixing time


Although designed to measure moisture in concrete mixing, the Hydro-Mix is also used successfully in other industries such as grain processing and animal feed, where it can be installed in a mixer, screw conveyor or auger, or in a chute. The Hydro-Mix moisture sensor is fitted so that it is flush with the floor of a planetary mixer or the side of twin-shaft mixers and screw conveyors.

The sensor takes measurements as the material flows over the ceramic faceplate during the mixing or transportation with a measurement depth of up to 10cm. There is a special mounting device designed to enable a Hydro-Mix moisture sensor to ride over the surface of flowing material on a belt conveyor called the Hydro-Skid. Using this device, measurements are then taken by the sensor as the material passes underneath.

Below are listed certain installation examples of the Hydro-Mix:

hydro mix egkatastasi


  • The ceramic faceplate and steel protection ring are the only parts exposed to wear when installed. Under normal use and regular maintenance, the sensor will last for many years.
  • Because the ceramic faceplate is easily replaceable on site or by an approved technician, it is a fast and cost effective solution to minimize downtime and the inconvenience of a returning to base repair.

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Protem Group S.A.

3, 35th Str., 133 41 Industrial Park
Ano Liossia / Athens, Greece
Τ. +30 210 5716500
F. +30 210 5710008
GCR No: 7633901000