Small, but a global leader all the same: Ehrler Prüftechnik Engineering GmbH (EP-E) has crafted a remarkable reputation in the field of high-precision testing and calibration systems. A preferred partner of the company is SICK – whenever possible, the company founder Alois Ehrler integrates the ultrasonic gas flow meter of the FLOWSIC product family into his flow testing equipment.
EP Ehrler Prüftechnik GmbH designs and builds complex testing and calibration rigs for pressure and flow commissioned by high-profile industrial clients and metrological institutes. The national metrological institutes and standards bureaus in Germany (PTB), China, Russia, the Czech Republic, Thailand, and Moldova work with primary standards from EP-E for the representation of volume flow and mass flow measurands for gases.
Since it was founded in 1983, the company has seen constant growth. In 2016, EP-E turned over around 10 million euros, so the capacity of production facilities was ramped up significantly. When asked about the secret to his success, Alois Ehrler is clear: “Big companies are focusing more and more on purely serial products, and we are profiting from this change.” The gap left by this change is filled by Alois Ehrler with specially made products or custom test benches, broadened to include all related services. “In the field of test bench technology we are the only company in Germany which can provide the complete spectrum of services – from design of the devices and technologies to calibration and maintenance.”
The start of a wonderful friendship
Through its shared affiliation with PTB, Ehrler first made contact with SICK AG ten years ago when working on joint development projects. In some ways, it was to be the start of a wonderful friendship. “The technicians at SICK are extremely skilled at what they do – you can’t help but take your hat off to that,” says Alois Ehrler, full of praise. “Another great thing is that SICK has remained a family-run company, which still makes it highly efficient.”
SICK also added a gas flow measurement device to its portfolio in the form of the ultrasound-based FLOWSIC600. Not only are these used for billing purposes in the natural gas industry, but are also highly useful in test benches. As sales director Oliver Hammel puts it, “the FLOWSIC family is perfect for our requirements. The devices are highly precise and cover a wide range for measurement and calibration systems up to 1:100 or 1:160. There is hardly any drift over a long period of time, and they can even put up with light contamination. There is also barely any drop in pressure on the measuring path.” Since then, EP-E recommends and prefers the ultrasonic sensors from SICK for flow measurement test benches whenever the requirements fit the profile and wherever permitted by specifications.
Suction air measurement with FLOWSIC600 DN400 for large engine test bays
Collaboration has paid off in various projects. EP-E has supplied two DN400 measuring paths to a manufacturer of large engines in France for use in suction air measurement in the engine test bays. High-accuracy tests were carried out to ascertain whether the V-engines, with up to 5,000 kW of power, were able to meet strict emissions standards. Two FLOWSIC600 units therefore provide high-precision data at up to 14,000 m³ flow volume. However, engine manufacturers for construction machines and lorries in Switzerland and Nuremberg use mobile calibration benches from EP-E. These contain suction measurement systems that work with FLOWSIC600 DN 200 in a four-meter-long measuring path. Alongside the high accuracy of the device, other key factors were the extremely low standard deviation of max. 0.5 percent and the long-term stability of the ultrasonic system.
Fan test bench
In the new development center of a renowned German fan manufacturer, a fan test bench from EP-E in line with ISO 5801 with integrated FLOWSIC600 DN200 and DN900 has been the core element of quality assurance since 2012.
In order to validate improvements to the fans in terms of performance and efficiency, the measurements must be highly precise. The fan characteristic curves are determined by operating the test specimen at a constant speed and continuously throttling the air flow. This measures the static pressure increase, the speed, and records electrical performance data. The measuring range is between 0 and 3,000 Pa for the static pressure, 0–12 kW for the electrical power, and 40–60,000 m³/h for the volume flow. All measurands meet the requirements of the standard with regard to measurement accuracy. With a measurement accuracy (without prior calibration) of ± 0.5% of the measured value, the FLOWSIC600 performs significantly better than the required standard of ± 2.0%.
There are further calibration opportunities for Ehrler Prüftechnik abroad as well. Alois Ehrler is focusing mainly on the natural-gas industry in emerging markets with pent-up demand in infrastructure. Firms in the oil and petrochemical, gas and water, and energy sectors offer great opportunities for EP-E test benches and the internationally renowned FLOWSIC ultrasonic gas meters – both individually and as a whole.