Cause Analysis of Pneumatic Lift Pump

1, Roots blower failure 1.1, Roots blower outlet relief valve pressure set value is small Early trial production, with the increase of mill feed volume, appear to enhance the pump blocking material. Roots blower current value of about 65%, is a normal range, but Roots blower outlet safety valve exhaust. On-site pipeline barometer readings did not reach the safety valve emptying pressure 80kPa. Re-adjust the safety valve pressure screw, such blocking material can be ruled out. 1.2, Roots blower triangle belt loss or burn-in V-belt wear aging or tensioning of the new triangle is not suitable, easy to make the triangle belt off or burning. For example, the central control room screen shows a Roots blower current value dropped from about 70% of normal to no-load current 40%, while the other two Roots blower current from about 70% to 80%. In the control room did not pay attention to this alarm, switching standby Roots blower is not timely, leading to the pneumatic lift pump blocking material. The on-site inspection revealed that the safety valves on the outlet pipes of the three Roots blowers were all exhausted outward. The triangle of the first Roots blower was dropped off or burnt out, causing the motor to run idle, resulting in an increase in the current of the other two blowers. Switching to a backup Roots blower solves the problem. 1.3, Roots blower outlet check valve spool off, wear and tear of the valve cut-off valve Roots blower outlet check valve role is to prevent the pressure air flow back to the rotor cavity after the shutdown. Globe valve pneumatic control, open before the fan motor operation, shut down after the motor shutdown, cut off the anti-channeling pressure air flow. Due to the cut-off valve wear and tear of the valve plate, resulting in pressure flow from the gap anti-channeling, impact check valve spool, a long time, resulting in spool off. The blocking phenomenon caused by such causes is as follows: The central control room screen shows that the current value of three Roots blowers drops from about 70% of the normal value to about 40% of the no-load current instantaneously. On-site inspection of gas lift pump blocking material, but 3 Roots blower safety valve does not exhaust. Air flows from the failed Roots blower through the exhaust pipe, rotor chamber to the suction line. Stop the Roots blower, the shut-off valve is closed, the other two Roots blower current value instantly increased from 40% to 80%, safety valve exhaust. 2, pneumatic lift pump canvas layer damage, air chamber material due to damaged canvas layer, the feed pump to enhance the raw material is not very good gasification, so that the ability to reduce pump delivery, when the feed volume exceeds the pump Of the transmission capacity, the occurrence of blocking material. 3 Roots blower fan current values ​​are about 80%, safety valve deflated. Approach: no need to stop immediately replaced, usually wait until the downtime and then replace the canvas. On-site treatment may not need to open the pump body manhole door to discharge material, just open the big raw material warehouse top bag dust removal exhaust fan inlet valve, and at the same time chooses to open 3 Roots blowers to pump the material in the body to the air. 3, the incoming wet agglomeration due to material factors lead to the airlift pump plugging material is mainly caused by moisture, especially after humidification tower wet end blocking material, clear down the wet material into the pneumatic lift pump by the screw conveyor, Can not be vaporized away. The control room showed 3 Roots blower current values ​​are about 40% of the no-load current, the safety valve does not deflate, but the feed chute is diffuse material, percussion pump body, sound dull. Approach: Stop raw mill system, open the pump manhole, manual shoveling, clear canvas layer and then reboot.