Apparatus and method for insuring and controlling turbulent flow for cleaning ducts

摘要

This invention concerns a system for insuring and accurately controlling the turbulent flow of a pressurized mixture of a gas and a cleaning fluid for purging and cleaning ducts. The pressures of cleaning fluid and the gas are continuously sensed and transduced into electrical signals for controlling valves for the pressurized gas to maintain and insure its pressure at a predetermined amount relative to the pressure of said cleaning fluid, so that when the gas and fluid are mixed in a turbulator, turbulent flow is insured. The improvements of this circuit include a pressure sensor transducer for sensing the pressure of the input of the air to the turbulator and feeding it back to the main air pressure transducer for accurately maintaining a predetermined ratio between the gas and cleaning fluid pressures within less than about 1 psi in at least pressures of 150 psi. A pressure warning signal indicates when the gas and/or cleaning fluid pressure is too low to produce effective turbulent flow. Furthermore, since the circuitry is so sensitive, a low pass filter is connected to the output of the cleaning fluid transducer to prevent unnecessary operation of the valves that control the gas pressure to the turbulator when the circuit is in its standby mode, thereby increasing the life of these gas control valves. An enrichment circuit for the cleaning fluid pressure sensors may vary the differences in pressure between the cleaning fluid and gas, not only for different cleaning fluids, but also during turbulation. Furthermore, the accurate control of the relative pressures of gas and cleaning fluid in the turbulator enables the turbulent flow mixture not only to clean the ducts, but also to simultaneously purge them.