Analysis of several main causes of diaphragm wear of diaphragm pump

Analysis of diaphragm pump diaphragm wear of the main reasons, under normal circumstances from the following analysis, pneumatic diaphragm pump diaphragm working pressure 6MPa, in the import and export material process, the diaphragm on both sides of the force, the maximum 4800kN, due to continuous alternating force, easy to damage cracking, diaphragm pump diaphragm easy to damage the reasons are as follows:

1. Due to the constant volume of the diaphragm chamber, if the feed is unstable and the pressure is low, the material level of the feed compensator is lower than 12m, and the material level in the pressure stabilizer is abnormal. When the feed is fed, the slurry in the pump is separated to form a gap, resulting in a lack of material, empty pump, hammer or impact or even cavitation, which increases the variable stress under the diaphragm and increases the frequency, resulting in fatigue damage or breakdown of the diaphragm.

Second, the air in the diaphragm chamber is not clean, and the volume of gas changes with the change of the pressure of the propulsion fluid, forming an air hammer, and the local force of the diaphragm increases, breaking the diaphragm.

3. If the feed temperature exceeds the specified temperature, it will accelerate the aging of the diaphragm. If the steam bubble is generated in the slurry, the gas enters the diaphragm chamber or the unloading valve leaks, the pressure of the propulsion fluid will decrease, resulting in uneven stress and fatigue damage of the diaphragm.

Four, the feed contains large granular crystallite, stone or large material or the solid mass percentage of slurry is more than 2%, causing the valve to jam, resulting in pump pressure fluctuation, or due to the valve assembly, the positioning of the valve cone is not correct, causing the stabbing valve, resulting in the diaphragm instantaneous force increase, resulting in rupture.

5. The feeding and discharging of the diaphragm chamber are controlled by the probe to detect the position of the control rod. If the magnetic ring on the control rod is weak, the probe can not detect the signal, and the oil can not be replenated in time, resulting in excessive force on one side of the diaphragm and rupture.

Six, the diaphragm control rod bearing sleeve is seriously worn, so that the control rod eccentric, subsidence, diaphragm stress increase, easy to crack diaphragm.

Seven, the unit pressure difference, causing pneumatic diaphragm pump overpressure, diaphragm withstand instantaneous force increase caused by rupture.

Eight, the crosshead, piston or cylinder lining is loose, crosshead guide rail, crosshead bearing installation is incorrect cause piston hammer, will make the hydraulic imbalance; Pump frequently jump stop, will also make the diaphragm instantaneous force, resulting in diaphragm rupture.

9. Nitrogen package is pre-filled with 2.2MPa nitrogen, which has good damping effect. During operation, the pressure reflected on the pressure gauge is the operating pressure rather than the pressure of the nitrogen package (which can be seen only when the pump is stopped). If the nitrogen package is damaged or the pressure is reduced during operation, the diaphragm pump runs in the undamped state, which will lead to the hydraulic imbalance and the diaphragm is easily damaged by impact.