Background: Combustible gases, such as propane, are routinely mixed with air to adjust their calorific value. The conventional instruments used to measure the ratio of the mixture of combustible gas and air are large, heavy, and expensive.

Project: Product Resources engineers developed an entirely new type of instrument to measure the effective ratio of combustible gas to air. This instrument operates on the principle that the velocity of sound is a function of the density of the gas in which it travels. If the velocity of sound in both propane and air is known, then the ratio of a mixture of these two gases can be calculated by measuring the velocity of sound in the mixture. The Product Resources Gas Gravitometer also provides a 4-20 mA output for process control and has alarms for out-of-range measurements.

Technologies: ultrasonics, embedded microprocessor measurement and control, process control feedback loops, intrinsically safe (energy limited) circuit design

Back to Engineering Design Services