Structure Design And Performance Analysis Of Double-Face Chemical PΜMP Seal Certain Car

Chemical pumps are widely used in industries with special requirements such as petroleum,chemical,pharmaceutical,and food.They work in high-temperature,high-pressure,and highly corrosive environments for a long time,and are prone to leakage during operation,seriously affecting product quality and machine service life.Mechanical seals,with the advantages of good sealing performance,simple structure,and low manufacturing cost,are commonly used for sealing chemical pumps to reduce pollution and improve product quality.As a type of mechanical seal,double end face seal has better sealing performance due to the injection of isolation liquid in its isolation chamber,making it the preferred seal for chemical pumps carrying toxic and volatile media.The dual face chemical pump sealing system consists of two sets of sealing pairs composed of dynamic and static rings,an isolation chamber between the two sets of sealing pairs,and a sealing ring between the sealing pair and the end cover.Due to harsh working conditions and relatively complex structures,the sealing of double face chemical pumps is prone to failure,leading to safety accidents.Due to the differences in the carrying media of chemical pumps,there are different requirements for the performance indicators of double face seals.Structural design and optimization are the key to achieving the performance indicators of double face seals.The ZTJGB-100S double end chemical pump with lime slurry as the bearing medium often experiences seal failure due to improper structural design and frequent damage to the dynamic ring and seal ring deformation during operation.This article focuses on the optimization design and performance analysis of the structure of the sealing system of this model.The main work carried out is as follows:（1）Analyze the causes of common failure in the sealing system of ZTJGB-100S double end chemical pump.In a double face mechanical seal system,due to the large pressure difference between the inside and outside of the sealing medium,the sealing auxiliary ring and sealing ring near the end cover side in the system are prone to damage,resulting in practical results.Optimize the structure of components that are easy to implement in the dual face sealing system to improve the sealing performance of the system.（2）The finite element method is used to optimize the design of the dynamic ring structure of the sealing pair near the end cover side in the double end face sealing system.Analyze the influence of the slope angle of the sealing auxiliary ring on stress,deformation,and service life.The results show that when the slope angle of the sealing dynamic ring is 7°,the maximum stress and deformation of the dynamic ring increase from4.70MPa and 4.61,respectivelyμM has decreased to 4.68MPa and 4.52μm.The service life has increased from 1.3x10¹² to 2.1x10¹² times.The optimization of slope angle is beneficial for reducing internal stress,reducing overall deformation,and extending its service life of the sealing dynamic ring.（3）Establish a finite element structural model of the end cover side sealing pair,and study the magnitude and distribution of stress on the contact surface caused by changes in the inner and outer diameter of the moving ring in the sealing pair contact surface.The results show that keeping the original outer diameter of the moving ring at 69mm and reducing the inner diameter by 0.1mm can increase the contact surface of the sealing pair by 8.5mm2,increase the stress near the outer diameter,and relatively lower the stress near the inner diameter,resulting in a larger overall stress value.Therefore,appropriately reducing the inner diameter of the contact surface of the moving ring and increasing the contact area can effectively improve the sealing effect.（4）On the basis of analyzing the failure reasons of the original O-ring close to the end cover,a finite element model of the O-ring is established to compare and analyze the influence of different cross-sectional diameters of the O-ring on key technical indicators such as deformation,compression,compression rate,and shear stress.The results show that the O-ring with a cross-sectional diameter of 4.6mm experiences severe deformation due to its large relative size to the sealing gap and the excessive compressive stress it bears;The O-ring with a cross-sectional diameter of 3.5mm is relatively small in size and can easily form gaps when compressed;The O-ring with a cross-sectional diameter of 3.7mm has smaller deformation,compression rate,and shear stress.Therefore,in practical use,priority should be given to selecting an O-ring with a cross-sectional diameter of3.7mm to improve sealing effectiveness and reduce production costs.（5）In order to further verify the structural optimization effect of the double end chemical pump sealing system,dynamic and static test benches were used to compare and analyze the leakage amount of the system before and after optimization using the single factor method.The results show that under a load of 8kg,with a linear speed of 25m/s and a testing time of 4h,the dynamic leakage can be reduced from 5m L/h to 4m L/h.The optimized design of the sealing structure of the double end chemical pump can effectively improve its sealing effect.