Hydronix is the world`s leading manufacturer of digital microwave moisture measurement sensors. Established since 1982 we have installed over 85,000 sensors across a wide range of industries in over 80 countries worldwide. Our moisture sensors are used successfully in applications which include concrete, aggregates and asphalt as well as organic materials such as animal feed, grain, nuts, oils and biomass products.
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- Industry Type:
- Monitoring and Testing
- Market Focus:
- Globally (various continents)
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Hydronix sensors are installed in a batch or continuous process where there is a requirement to measure moisture in real time. The sensors use a contact measurement technique which compared with other methods of moisture measurement is least affected by impurities, colour, particle size or temperature.
Our applications experience and expertise not only includes the harsh environments of a concrete mixer or aggregate bin but also other drying, wetting, monitoring or control processes where the material is free flowing.
Hydronix pioneered the use of microwave energy to measure moisture and we continue to develop solutions and new products using the latest technology. We are committed to ensuring that our products and services add value to our customers’ processes while reducing costs and the amount of wasted materials. As a global company we operate through a network of Hydronix trained and experienced resellers which enables us to provide a local solution in your own language.
Hydronix was the first company to develop microwave moisture sensors specifically for use in the concrete industry and we are now recognised as the world leader in our field. With a focus on continued research and development and over 30 years experience, Hydronix has successfully introduced digital microwave moisture measurement into a broad range of other industries, both mineral and organic. Below are just a few of the key reasons why end users and system integrators should choose Hydronix as a partner.
- Unique digital microwave measurement technique for ultimate precision
- Unique sensor features such as the choice of digital measurement modes
- Identical sensor measurement characteristics
- Rugged design, built to last
- Commitment to excellence through continued research and development
- Global support in your local language
- Outstanding warranty, support, service and repair
Hydronix Digital Measurement Technology
Since the development of the original Hydro-Probe microwave moisture sensor over 30 years ago, Hydronix has led the world in the field of moisture measurement. Unique to Hydronix, our digital microwave moisture sensors not only have a digital measurement technique which provides a very precise level of accuracy but also a choice of measurement modes that enable the user to select the mode best suited to their material. Combined with Digital Signal Processing filters for improved performance and a variable frequency technique which is designed to operate in a bespoke range as opposed to an off-the-shelf frequency such as 433MHz or 2.4GHz, Hydronix sensors provide the user with the most accurate microwave moisture measurement available. Further details on our digital technology can be found on the Hydronix technology page.
Identical Sensor Characteristics
During manufacture each sensor is factory calibrated to a standard Air and Water datum in a temperature and humidity controlled environment. This ensures that each sensor has identical measurement characteristics and allows material calibration data to be copied between sensors.
Hydronix Moisture Sensors - Built to Last
Hydronix digital microwave moisture sensors are built to last, and with many years experience designing sensors for the harshest of environments reliability, temperature stability and wear resistance is assured. Manufactured of stainless steel and with a ceramic faceplate, each sensor undergoes a series of rigorous tests before being sold. Many sensors have been in the field for upwards of 10 years without requiring a return-to-base service, meaning that they are extremely cost effective when compared with equivalent equipment.
Continual Research and Development Programme
It was Hydronix that introduced the first microwave moisture sensors into the concrete industry over 30 years ago and our continual product development has ensured that we have consistently remained at the forefront of technology. Our dedicated Research and Development team of experienced engineers based in our UK Head Office are committed to maintaining our market leading position through technological advancements ensuring that Hydronix sensors are not only extremely accurate but also easy to use.
Hydronix is committed to delivering an excellent service to all of our customers. We achieve this by operating through a global distribution network of fully trained resellers. This ensures that both system integrators and end-users can purchase products locally and receive training, service, support and advice in their own language. Our sales team and experienced engineers and support staff work closely with our resellers and end-users to ensure that every customer is 100% satisfied with their investment in Hydronix equipment and we welcome feedback from our customers.
Outstanding After Sales Service
Hydronix understands the cost implications of plant downtime and the requirement to act quickly in the event of failure. Our products are covered by a choice of warranty options providing our customers with up to 4 years warranty and an immediate replacement service in the unlikely event of unit failure. Further details can be found on our Warranty page.
Digital microwave moisture measurement is recognised today as one of the most important methods for online measurement of bulk materials. Hydronix has a range of sensors that utilise digital techniques for measuring the change in a microwave resonator frequency with changes of moisture in the material. This type of sensor has very significant benefits over existing analogue techniques. Possibly the most important factor is that this technique provides a greater accuracy of measurement over a far wider range of moisture contents, and is suitable for working with a far wider range of materials.
Digital Measurement Technique
Hydronix microwave moisture sensors use our own unique digital measurement technique which measures multiple material parameters. These parameters are then precisely combined using a variety of advanced algorithms to deliver the optimum performance for a given application. This technology enables the sensors to be easily configured for peak performance in any material giving a linear response to changes in moisture.
Digital Signal Processing Filters
Digital microwave sensors have on-board electronics that allow measurements to be immediately processed and have noise reduction filtering applied to generate a stable output reflecting the moisture content of the material to plant operators or automated controls. Normally, filtering has the side effect of reducing the responsiveness of the sensor output to changes in the moisture content. However, Hydronix technology allows for the use of advanced Digital Signal Processing (DSP) filters for faster response times to changes in moisture content whilst retaining the same level of noise reduction.
Choice of Measurement Modes
Hydronix sensors have the ability to use different measurement modes to achieve the best signal response to different materials. In the concrete industry for example, different aggregates have their own distinct dielectric property behaviour and will therefore respond differently to each of the underlying measurement modes. These response differences between the modes are also applicable to variables in the application itself. The best mode may now be selected for the material and the application to best account for the temperature range, precision required and bulk density changes over time.
Variable Frequency Technique
Hydronix sensor design starts and finishes with performance as the key design objective. The variable frequency technique is designed to operate in a bespoke range as opposed to an off-the-shelf frequency such as 433MHz or 2.4GHz. This ensures that the sensor is continually focused on detecting changes in the number of water molecules in the material with no interference from temperature changes and variations in the ionic content of the material (commonly salt content).
Although microwave moisture measurement has been proven to be superior to a resistive or capacitive method, the analogue measurement technique has a number of limitations when compared to a Hydronix sensor which uses digital measurement technology.
An analogue microwave sensor measures moisture through a combination of frequency shift 'f'' (the left to right movement of the response) and amplitude attenuation 'A' (the change in the height of the response) of the resonator. This combination is measured as a single analogue response and therefore frequency shift and attenuation cannot be separated. In the 1980’s Hydronix introduced an innovative digital microwave sensor that enabled the frequency shift component to be accurately measured using precise digital techniques. This development resulted in an improvement in accuracy and also a very significant extension of the moisture range for which the sensor would give a true linear response as moisture levels increased.
Less advanced sensors simply measure a change in amplitude at a fixed frequency. Measuring across a custom frequency range gives more accurate results than those sensors that work within the confines of a single frequency using an open band such as those used by Burglar Alarm Systems (433MHz) or Wi-Fi ( 2.4GHz). The components required to manufacture a sensor that measures a frequency shift as opposed to a change in amplitude at a fixed frequency are more complex but provide a superior result.
The difference between a digital multi-frequency measurement and an analogue measurement at a fixed frequency (f1) measuring just the change in amplitude can be seen in the diagram on the right. As the moisture increases the frequency shifts from f1 to f2, f3 and then f4. The frequency shift between each is similar in magnitude. A sensor with a digital measurement technique will continually scan the frequency response and will track the equal changes in frequency as the material becomes wetter.
For the same moisture changes, a single frequency sensor simply measuring the change in the amplitude at frequency f1 will measure the changes from A1 to A2, A3 and then A4. It can be seen that the sensor progressively loses the ability to register a change in reading as the material becomes wetter. Typically, a good analogue sensor will lose the ability to register additional changes in moisture from about 12% onwards. This not only affects the sensors ability to register changes in moisture above this level but it also means that the entire moisture curve lacks linearity as shown below.
Sensors that use a non-linear measurement technique require the reading to undergo significant mathematical manipulation in order to output what appears to be a linear response to changes in moisture. This highlights a key difference between an analogue sensor that claims to be digital because it can process the signal and output a seemingly linear measurement and a sensor (such as those manufactured by Hydronix) that uses a digital microwave measurement technique that is inherently linear.
Why do we want to measure moisture in materials? A large percentage of industrial processes are very similar in the respect that they blend and mix a variety of raw materials together to produce an end product. The raw materials will contain a variable amount of moisture and during the process water may be added or removed by means of a drying process to produce a product with specified final moisture content.
Installing Hydronix digital microwave sensors into a new or existing system is simple and for minimal cost the benefits are extensive, often providing payback on the capital outlay in a few months. The benefits of maintaining optimum control of moisture may be briefly summarised as follows:
- Reduce costs by reducing the amount of spoiled material.
- Save energy costs by only heating driers / burners to temperature required.
- Save energy costs by reducing the amount of mixing time required.
- Reduce additive costs by knowing the moisture levels of your raw materials.
Increase Production Levels
- Automation usually increases production rates.
- Reduce the amount of time needed to rework.
- Improve quality – all batches / outputs are consistent.
- Easy adjustment to changes in moisture in materials to ensure consistency of final product.
There are several methods of measuring moisture in online process control apart from the microwave method, these include resistive, capacitive, infra-red and nuclear techniques. Each of these have specific problems and therefore do not provide an ideal solution for the plant controller.
- This technique is prone to error because water does not act as a consistent conductor. For example distilled water is a non-conductor of electricity, whereas salt water will conduct electricity. This technique therefore is severely affected by any contaminants in the water.
- This is a more common method of moisture measurement but it is still affected by contaminants in the water. It also has a limited effective working moisture range.
- This is a very common method of measuring moisture but as this is a reflective technique, it will only provide a surface measurement which will not be representative of the total moisture in the product. The technique is expensive and requires specially calibrated equipment and a dust or moisture free environment.
- The Nuclear moisture measurement technique offers an accurate method of moisture control. However it is not suitable for many industries, can be extremely expensive and it also requires a large volume of material to operate successfully.
Compared with these other methods of moisture measurement, the Hydronix microwave method is the least affected by impurities, colour, particle size or temperature and is totally safe.
The Microwave Method of Moisture Measurement
To accurately measure moisture, it is necessary to determine the number of water molecules present in the material. To enable this, the material to be measured is passed across the ceramic faceplate or head of the microwave moisture sensor which radiates an extremely low powered electromagnetic field. Due to the dipolar effect of a water molecule, the resonant frequency of a microwave resonator changes with variations in moisture content. It is these variations that are detected by the sensor electronics. They are then measured in terms of 'unscaled units' which are scaled by a process of calibration to provide a precise readout of the moisture present. The resulting signal is sent via an analogue (0-20mA [0-10v] or 4-20mA) or RS485 digital communications link back to the plant control system, allowing adjustments to the water addition process to be made automatically.
Established in 1982, Hydronix specialises in the research, development and manufacture of digital microwave moisture measurement systems. Our products are used to reduce manufacturing costs and to improve the quality of the finished product and with over 65,000 sensors installed worldwide Hydronix is the recognised world leader in microwave moisture measurement.
Hydronix has been involved in many prominent projects where controlling moisture has been critical and some of these are listed below. Our applications page lists a number of other successful applications using Hydronix equipment.
- Great Man-Made River, Libya (1990)
- The new Hong Kong Airport, Hong Kong, (1998)
- Malmö Tunnel and Bridge, Denmark, (1995-1999)
- Rion-AntiRion bridge in Greece (1999)
- Olkiluoto nuclear power plant, Finland (2005)
- Longtan Dam, China, (2005)
- Freedom Towers, New York, USA (2006-2012)
- Heathrow Terminal 5 (2008)
- Flamanville – Nuclear power generation plant 3rd generation in France (2007)
- World Cup Stadium, South Africa (2010).
- Panama Canal extension, Panama (2012)
- Olympic Cross City Railway, England, (2012)
Hydronix remains a family company and we take great pride in ensuring that we offer personal and responsive customer support. We do this directly and also through a network of resellers across the world. All of our resellers are very experienced and fully trained in all aspects of our equipment, including installation, training and support. This enables Hydronix to provide advice and support to all of our OEM and end user customers in their own language. In addition we have translated our documentation and software as well as our supporting sales literature into many languages to ensure that we offer a truly global service.
Hydronix places great emphasis on working closely as a team both within our organisation and also with our partners and customers. Each member of our team plays an important role in making sure that Hydronix continues to provide a world class service in every aspect of our business. All of our staff have been chosen because of their experience in their individual fields, whether this is in specific applications, product development, administration, sales or technical support. The most important value at Hydronix is the ability to work together as a team and this extends from senior management through to all staff, both inside and outside the office.