Construction and technology of screw pile

　　The screw pile can absorb oxygen and nitrogen in the air together, and its adsorption capacity increases with the increase of pressure, but there is no significant difference between the equilibrium adsorption capacity of oxygen and nitrogen under the same pressure. Therefore, it is very difficult to accomplish the useful separation of oxygen and nitrogen only by the change of pressure. If the speed of adsorption is considered further, the adsorption characteristics of oxygen and nitrogen can be distinguished from the useful areas. The molecular diameter of oxygen is smaller than that of nitrogen, so the dispersion speed is hundreds of times faster than that of nitrogen, so the adsorption speed of carbon molecular sieve is also very fast, and the adsorption capacity of nitrogen is only 5% at the moment, so the adsorption at the moment is generally oxygen, and the rest is nitrogen. In this way, if the adsorption time is controlled within, oxygen and nitrogen can be separated from each other. That is to say, adsorption and desorption are completed by pressure difference. When the pressure of spiral pile increases, adsorption and desorption occur; when the pressure decreases, desorption occurs. The difference between oxygen and nitrogen depends on the difference of adsorption speed. After controlling the adsorption time, the time is controlled very short, oxygen has been fully adsorbed, and the adsorption process is stopped before nitrogen can be adsorbed. Therefore, the pressure of PSA nitrogen production should be changed, and the screw pile should be controlled within lmin at all times.