The portable Model 2750 accurately and reliably measures hydrogen-in-CO2 and air-in-CO2 during maintenance purging of hydrogen-cooled turbine generators. These measurements assure that the purging proceeds quickly, efficiently and effectively. Switch-selectable ranges on the instrument make it easy to choose the measurement required. Plus, the 2750 features a third range that alerts the user to air leaks in the hydrogen cooling gas and thus helps assure optimum efficiency during normal generator operation.
Sensor Description
The sensor structure consists of an integrated heater located on a thin electrical and thermal insulating membrane. Two thin film resistors are used for heating and measuring the temperature of the membrane. Two resistors are integrated on the silicon beside the membrane for the compensation of the ambient temperature changes. Gases that have lower density than air (CH4) decrease on the surface membrane temperature. Gases with densities higher than air (CO2) increase the temperature of the measuring resistor.
Design
The 2750 is a rugged, portable, easy-to-use gas analyzer that monitors purge gases and the cooling gas in hydrogen-cooled turbine generators. Three selectable ranges monitor purge gas composition during maintenance purging and spot-checks hydrogen purity during normal generator operation. The portability of the unit eliminates installation costs and makes it easy to move between generators. There are no moving parts to wear out, no filters to change and no traps to clean; so, the 2750 is virtually maintenance free. A simple periodic calibration is all that is needed to assure years of trouble-free service.