CWD product series

The combustion calorimeters in the CWD series (Calorimetry, Wobbe Index, Specific Gravity) are proven systems for the precise determination of gas quality and all relevant measured variables. These include

• Calorific value and heating value

• Wobbe index

• Specific density

• CARI and air requirement

The CWD DPC (Direct Purge Certified) is a variant specially developed for potentially explosive environments. The device is designed for use in accordance with Class I Division 2, Groups B, C, D, T4 and therefore meets all requirements that apply in industrial plants with potentially explosive gas atmospheres.

The safety-related certification of the CWD DPC was carried out by SGS North America, a NRTL (Nationally Recognized Testing Laboratory). It confirms conformity to the following standards:

• UL 61010-1 (Electrical Safety)

• NFPA 496 (Purge and Pressurization Systems)

• ANSI/ISA 12.12.01 (Nonincendive Electrical Equipment)

The CWD DPC thus offers maximum safety and reliable measurement performance in demanding, sensitive industrial environments.

The system is designed for installation in closed rooms and requires an external power and compressed air supply. Thanks to its robust design, certified safety technology and precise measurement technology, the CWD DPC is the ideal solution for operators who need to carry out gas quality measurements in areas where the highest safety requirements apply – such as refineries, petrochemical plants, gas processing, power generation or industrial production areas with a risk of explosion.

The direct and continuous determination of gas quality using combustion calorimeters has been an established and extremely precise measuring method for over 60 years. With this thermal measuring principle, a defined gas volume is completely combusted so that all gas components are reliably converted. The energy released in the process is proportional to the Wobbe index, while the specific density of the gas is determined in parallel. The calorific value can then be precisely calculated from these two measured variables – regardless of the complexity or variability of the gas composition.

A key advantage of the CWD DPC is its ability to reliably detect even unexpected or unknown gas components. This makes the system particularly suitable for processes with highly fluctuating gas qualities, as is often the case with residual gases from chemical processes, substitute gases in the steel industry or refinery gases. The robust measurement technology enables stable, continuous monitoring even under demanding conditions.

The CWD DPC also meets the highest safety requirements. If the gas supply is interrupted or the process stops, the device ensures a quick, safe shutdown by extinguishing the flame within a maximum of 10 seconds. This ensures maximum operational safety in industrial plants.

Another technical advantage is that the system is not cross-sensitive to changes in the gas composition – for example due to the presence of O₂, H₂ or CO. As a result, the measurement remains stable, reproducible and accurate even with changing gas flows.

The CWD DPC thus combines decades of proven calorimetry, modern safety technology and maximum reliability into a powerful measuring system for critical industrial processes.