Safely monitor hazardous and explosive environments with the Vaisala HMT370EX

Fuel depot case for Vaisala’s intrinsically safe HMT370EX is ideal for hazardous areas up to zone 0 and 20.
Product Manager Juhani Lehto from Vaisala
Juhani Lehto
Product Manager for high-end products
Industrial Manufacturing and Processes
Industrial Measurements

When operating in hazardous environments it is essential that your equipment is ‘intrinsically safe’, a designation that certifies that equipment and wiring cannot release sufficient electrical or thermal energy to cause ignition. For decades those operating in hazardous environments have trusted the Vaisala HMT360 to measure humidity and temperature safely and reliably, even in zone 0 areas. Now the intrinsically safe Vaisala HMT370EX can provide the same safe and reliable measurement data, with several key new benefits. 

Improvements on a trusted design

Unlike the HMT360, the HMT370EX has a graphical display with data and trend viewing functions, making it much easier to monitor temperature and relative humidity over time. It also has a new anodized finish that offers better corrosion resistance – a particular benefit for offshore applications. For applications involving dust, the housing of the HMT370EX has been designed not to require a protective dust cover. Laser markings have replaced adhesive labels, providing a critical safety improvement as it means safety and identification information can’t become illegible. The HMT370EX is also compatible with the free Vaisala Insight PC software, making it easy to configure and calibrate. The HMT370EX features the latest materials and components throughout, including the state-of-the-art HUMICAP® R2 sensor for long-term stable measurement and corrosion tolerance. It also offers improved humidity measurement performance. The robust and rugged design has been extensively tested to ensure a long product lifetime. 

Ensuring a safe and high-quality finish

The entire HMT370EX transmitter can be installed in any hazardous or explosive area including zone 0. One such environment is paint booths in the automotive industry. Here it is essential to measure both relative humidity and temperature to ensure an even and consistent paint finish, but the solvents used in automotive paint are easily flammable. The HMT370EX is Ex-approved to be intrinsically safe in this environment, ensuring relative humidity and temperature remain at levels that ensure a high-quality finish. 

Flour dustAnother typical application for the HMT370EX is the tablet coating process in pharmaceutical manufacturing. In this process, a fine powder is sprayed to coat tablets with an even surface finish. This kind of fine powder can be explosive, so an intrinsically safe device is essential. The HMT370EX monitors the humidity and temperature to ensure that there is no clumping of the powder and the coating is applied smoothly. It also ensures that the quality of the medicine or its shelf life is not compromised by the powder being too moist. Bakeries and flour mills also need humidity and temperature measurements to ensure the quality of their final products, as well as protection from the flammability of flour dust. Similar issues with flammable fine grinding dust can be found in many other industries too, such as furniture making.


From hydrogen cooling to oil and gas applications

Hydrogen-cooled generators need to keep the hydrogen very dry to avoid corrosion, so constant reliable measurement of the relative humidity and temperature is essential, as is Ex-approved equipment because of the risk of explosion. Oil and gas drilling platforms also often require intrinsically safe equipment, either for specific hazardous areas or to simplify specification offshore. For example, HMT370EX is ideal for monitoring flight conditions in offshore helideck operations. For fuel tanks and chemical storage, the HMT370EX offers a dedicated sensor for measuring moisture in oil to avoid loss and maintain product quality.

To find out more about the HMT370EX and whether it’s right for your application, see the HMT370EX product page or contact us.



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