Because the size of pulverized coal is 200 mesh, fine powder, and fluidity, it often leaks many pulverized coal due to improper sealing at the head and axle end of screw conveyor. Asbestos packing, oil-impregnated wool felt, oil-impregnated asbestos rope and flexible graphite ring were used as sealing fillers, but the effect of leak control was not satisfactory. Pulverized coal is leaked around the equipment every day, which not only wastes but also pollutes the environment and affects civilized production.
An experiment was carried out on a screw conveyor, i.e. drilling through holes, tapping and adding oil nozzles on the outer ring of the head packing cover, and processing two oil grooves in the wall of the cover hole to connect with the oil nozzle hole. Butter gun is used to press grease into the oil tank from the oil nozzle and fill the gap between the surface of the rotary shaft and the inner hole of the pressure cap. The original asbestos disk root remains unchanged. This structure makes the pulverized coal sealed many times and achieves good sealing effect. Field test shows that the screw conveyor with an oil nozzle is obviously superior to that without modification. The practice has proved that this method is effective and can prolong the service life of the long spiral shaft of the screw conveyor.