Working characteristics of two kinds of air-driven boosters

To obtain high-pressure gas, air-driven boosters are widely used. The most common booster is called input pressure reduced booster (IPR booster). The IPR booster's output pressure is set by reducing the input pressure of the driving chambers. In this paper, a new kind of booster, expansion energy used booster (EEU booster), is proposed, which makes use of the expansion power of the compressed air in the driving chambers. Through analysis of the boosters, a mathematical model of the working processes is set up. Using the software MATLAB/Simulink for simulation, the motion characteristics of the piston, the variations of the pressure of the boosting chambers and the driving chambers, the characteristics of the output flow of the boosters were obtained. Moreover, a new energy consumption evaluation criterion of pneumatic system, air power, is briefly introduced. Simulation and experimental results of the boosters were conducted and the output air power and efficiency characteristics of the boosters were obtained. Results show that, first of all, the simulation results have a good consistency with the experimental results. Secondly, when the air source pressure and the output pressure are set at 0.6 MPa and 0.8 MPa respectively and the terminal pressure of the driving chamber is increased, the output flow of both the IPR and the EEU boosters increase stably. When the terminal pressure exceeds 200 L/min, the output flow of the EEU booster remains almost constant. Thirdly, with the same terminal pressure, the air power efficiencies of the two kinds of boosters remain the same. Lastly, if the output pressure is set at 0.8 MPa, under the optimum work state of the EEU booster, the output air power of the two kinds of boosters both decline with an increase in the boosting ratio. However, the output air power of the EEU booster is higher than that of the IPR booster by approximately 2.5 kW, which is about 1.4-4 times of that of IPR booster. When the boosting ratio is 1.6, the output air power of the EEU becomes 4 times of that of the IPR booster. This research can be referred to in the design of the boosters. (C) 2011 Elsevier Ltd. All rights reserved.