Relative Humidity / Temperature Transmitters
ABLE offer a range of electrical (capacitance) based relative humidity and temperature transmitters. Put simply, relative humidity (RH) is a measure of the water vapour content of air. More explicitly, it is the amount of water vapour present in air expressed as a percentage (%RH) of the amount needed to achieve saturation at the same temperature.
High humidity is a big problem for products with extreme sensitivity to moisture, such as certain pharmaceuticals. This is because it can alter the characteristics of the product until it becomes useless, which is why products like medical pills and dry powders and foodstuffs such as chocolate are stored in controlled conditions at precise humidity and temperature levels.
For standard HVAC/BMS applications concerned with environmental control and maintenance of the comfort zone in facilities such as offices, shops, museums, galleries and hotels, ABLE supply a range of high-quality room/wall and duct mounting relative humidity and temperature transmitters. Humans generally feel comfortable at temperatures between 22 °C to 27 °C and a relative humidity of 40% to 60%, therefore, these devices are designed to deliver optimum performance at these ranges and to be able to provide a 4-20mA or 0-10v output to match the requirements of different BMS manufacturers.
If the temperature rises, the relative humidity decreases, so any BMS must be able to detect the change and respond accordingly to rebalance the environment. This may be affected by an injection of water vapour and/or the use of a chiller unit to move heat from one location and transport it to another place to chill.
When considering applications with more demanding and aggressive atmospheres such as those found in industrial (chemical, petrochemical, pharmaceutical, power, utilities) and offshore platform environments, ABLE recommends the Rotork-Schischek range of rugged, contemporary, reliable and explosion proof HVAC products. Housing choices are die cast aluminium or 316L stainless steel. Schischek’s products are certified for use in ATEX Zone 1 and 2 (gas) and 21, 22 (dust) hazardous areas with no intrinsically safe wiring requirement. Available options include safe area variants, stainless steel (AISI 316) housings and offshore/marine seawater resistant coatings.