Wet-and-Dry Bulb Hygrometer

A wet-and-dry bulb hygrometer uses two identical thermometers. The dry bulb is exposed directly to air. The wet bulb is wrapped with gauze connected to distilled water. Evaporation from the wet gauze removes heat, causing the wet bulb reading to be lower than the dry bulb.

Humidity Principle

The lower the relative humidity, the faster water evaporates from the gauze and the larger the temperature difference between dry and wet bulbs. Once the two temperatures are known, relative humidity can be calculated or found from a prepared table.

TH135 Controller

TH135 measures dry and wet bulb temperatures using high-accuracy Pt100 sensors. It combines the classic psychrometric method with modern electronic control to provide accurate industrial humidity measurement and control.

Typical Uses

TH135 can work with humidifiers and dehumidifiers to form a humidity control system for food processing, pharmaceuticals, environmental monitoring, timber drying and other industrial or civil applications.