Ultrasonic Flow Sensors for the Heating Industry: From Developer Startup to Mass Market OEM

July 1, 2017, 10 minute read

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The ultrasonic principle in flow sensors has also been used in the heating industry for several decades. Due to the high unit price of the sensors, the technology was not interesting for use in mass market products in the heating industry for a long time. A highly specialized startup has now changed that.

Allengra GmbH stands as a pivot to innovation in the field of precision instrumentation. Since its inception in 2005 by engineer Dipl.-Ing Raul Junker, the company has been the leader of ultrasonic flow sensor technology. Operating from its headquarters in Ravenstein, close to the economic hub of Heilbronn, Allengra GmbH has carved out a niche in producing high-quality, reliable ultrasonic flow sensors. These sensors are integral to a multitude of industries, ranging from pharmaceuticals to petrochemicals, ensuring that Allengra's expertise contributes significantly to the operational efficiency and success of its diverse clientele.

High precision and long service life

When Raul Junker contacted a sensor chip manufacturer from Karlsruhe-Stutensee for a well-known German water meter manufacturer in 2000, it was clear to everyone involved in which direction the water meter market must develop in the long term. Although mechanical water flow measurement is still one of the most commonly used meter types, ultrasonic flow measurement is offering more and more convincing advantages. As a non-invasive method, it is particularly suitable for use in heating systems and in industry, for example to determine consumed volumes or with the help of control technology to optimize entire processes.

Ultrasonic sensors do not use mechanical counters. As a result, there is no wear of individual parts and the precision of the measurement is retained until the end of a very long service life. However, around the turn of the millennium, the pure production costs of mechanical meters could not be achieved with an ultrasonic sensor.

First sketch on a napkin

In 2005, Junker started to set up the Allengra company with the aim of developing a low-cost alternative to the mechanical meter. He already has a clear idea of the hydraulics and draws a sketch on a napkin during a meeting with the chip manufacturer. Their then managing director Andreas Larsch was so convinced of the idea that he had mobilized all his company's resources to complete a working prototype together within a few weeks.

The breakthrough from developer to manufacturer

At the same time, the global company Viessmann was interested in a suitable volume flow sensor for use in its premium wall-mounted gas appliances. The motivation for Viessmann was to work with Allengra for the clear metrological advantages of ultrasonic technology and also, for the compact design of the volume flow sensor.

The high-precision time-to-digital chip that would form the processing heart of the sensor was ideally suited for this application and, with the support of the chip manufacturer, Allengra was able to complete the design and electronics within a short period of time. The development work began in the summer of 2010 and just one year later Allengra delivered the finished series volume flow sensor to Viessmann.

Pressure measurement in addition to flow measurement

Based on the new generations of sensor chips and inspired by Viessmann's success, Allengra soon after this first project consistently expanded the functionality of the sensors and thus, the possible applications. When another customer from the heating industry considered a combination of pressure measurement with ultrasonic flow measurement in 2013, Allengra started a new OEM development and has been supplying sensors for integration in compact hydraulics as a module since 2016.
Additionally to flow and pressure measurement, this sensor also combines temperature and differential temperatureflow/return in one module.

The advantages of this solution are:

  • Single Electronic Unit: The system utilizes just one electronic unit, simplifying the design and reducing complexity.
  • Efficient Communication: Through a single bus interface, multiple pieces of information are transmitted to the heater controller simultaneously.
  • Integrated Sensors: Manufacturers receive all necessary sensors from a single source, streamlining production.
  • No Separate Sensor Housing: Integration with the device hydraulics eliminates the need for a separate sensor housing.

Energy savings of up to 15% through hydraulic balancing

The use of the ultrasonic flow sensor is also ideal for another important application in the heating industry: hydraulic balancing
Allengra flow sensors have been used successfully in Viessmann "Vitoflow" for several years in radiator heating systems.

Either the ultrasonic flow sensor integrated in the boiler or a sensor built into a measuring kit is used to determine the flow resistance of the entire radiator heating circuit and finally to calculate the pre-settings of the radiator valves and send them to the installer. The integration of ultrasonic flow sensors in the heating circuit distributor enables the measurement to be extended to surface heating circuits, for example in underfloor heating. In this way, permanent hydraulic balancing can be carried out in combination with a control valve.

All surface heating circuits in a system can thus be permanently coordinated with one another. This makes it easy to react to the effects of a heating circuit with a temporarily higher or lower heating requirement on the other heating circuits. If the heating circuit pump is included in the control, it can be operated at the lowest possible speed to save energy.

Since the implementation of a hydraulic balance for new systems as well as for extensions and changes to existing systems is now mandatory, Allengra already makes an important contribution with the achieved energy savings of up to 15%.

Ultra-compact flow measurement also for industrial and dosing systems

Integrated interfaces and extended functionality now enable new features in ultrasonic flow measurement; the main advantage of this one-chip solution lies in the significant increase in robustness and accuracy of the measurement. In 2015, Allengra developed a very compact and cost-effective sensor variant based on this new chip for various applications such as heating installations, industrial plants and dosing systems, being suitable for all liquid, water-like media with or without additives.

Through experience and observation to the Smart Valve

With the different test benches that Allengra set up during its many projects, certain basic elements in the equipment crystallized for the flow sensors, which were used again and again; a sensor for the pipe pressure, one for the differential pressure, combined with a sensor for the static pressure, a temperature sensor and a sensor for the flow and volume of the medium, as well as an actuator and a valve for flow control. This set of requirements also gave rise to the idea for the “Smart Valve”.

Allengra started in 2015 with the design of a simple and compact sensor with a well-evaluated and tested actuator, combined with a ceramic valve control system. Some of Allengra's existing customers participate in the development of the highly integrated valve, and over the years that follow, more companies are showing interest in the OEM product to upgrade and upgrade their heating and dosing applications. After three years of intensive testing and evaluation, Allengra has achieved full integration of the Smart Valve and presented it at the ISH 2017 in Frankfurt. The result fully meets the expectations of Allengra founder Raul Junker and his team:

The Smart Valve offers several important advantages. It contains just one board on which you can find all the important interfaces, plus a connection cable and it consists of just one housing that brings all five sensors together in a small space without the OEM having to manage additional sealing points.

Own prototype production line for ceramic technology

For the smart valve, Allengra also invested in a prototype production line for ceramic technology, which offers the advantage of low torque requirements and high density. The actuators were developed, evaluated and optimized in cooperation with an experienced gearbox designer. In order to meet all the requirements for mechanical design and production, Allengra also invested in a new milling machine with a direct CAD/CAM connection and expanded its machine park with several plastic injection molding machines.

Control valve planned for gas and air as well

The ultrasonic control valve can handle a temperature range of 5-100 °C and a pressure between 0-6 bar with communication that can work via UART, PWM, via a pulse output and other ways. A lithium battery that will last for several years, the Smart Valve consists almost entirely of plastic (brass if required). With no mechanical moving parts in the sensors, small floating particles, dirt or sand do not affect the long-term stability or the accuracy of the measurement.

The control valve is very well suited for use in the food industry, since the hygienic requirements can easily be met due to the avoidance of dead spaces. Allengra plans to develop another control valve in the coming years that can also be used for gas and air on the same principle.

"Just a few years ago, this application was nothing more than a dream"
-says Raul Junker.

The synergies between our innovative customers, partners and our excellent team made the realization possible.
With the inauguration of our new production building in 2017, we can also guarantee that the Smart Valve is ready for series production.

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