Design And Research Of Mechanical Seal With External Driving Middle Rotating Ring

With the rapid development of industry, contacting and non-contacting mechanical seals are widely used in different fields. When at high speed, high temperature and high pressure, mechanical seal of pumps, compressors and reactors have many problems, such as overheating, excessive leakage, exacerbated friction and wear, etc. While at very low speed, there is not enough opening force for non-contacting mechanical seal to open the two sealing rings, namely rotator and stator. In order to solve the above mentioned problems, a mechanical seal with external driving middle rotating ring is designed based on TRIZ, then research on the new mechanical seal is carried out by theoretical calculations and experimental analysis, details are as follows:(1) The introduction of the basic working principles and structure of the mechanical seal. It puts emphasis on the basic structure and performance parameters of spiral groove mechanical seals. Mathematical model for performance parameters, such as the fluid film stiffness, leakage and other performance parameters are derived from the Navier-Stokes equations.(2) Innovative design of mechanical seal by TRIZ theory. Firstly, analyze the difficulties; determine that it is the relative speed of seal face that is to be improved. Then, according to table of contradictions and solution models, try to find out related techniques to deal with the difficulties. After that, a method to change the relative speed of stator and rotator in the spindle is put forward, which adopts a inventive external driving middle rotating ring to get rid of the influence of spindle speed. Finally, a mechanical seal with middle rotating ring of belt driving is designed.(3) Solve the mathematical model in Matlab, and analyze the calculating results. The results show that: while the external driving mechanical seal gets a higher value of seal leakage rate and friction torque than ordinary non-contacting mechanical seal, it enables better and stronger opening force and stiffness than ordinary non-contacting mechanical seal when at work.(4) Experimental study of mechanical seal with middle rotating ring. Adjust the external pressure, the middle rotating ring speed and main motor speed at seal leakage test bench. Leakage test is carried out for the mechanical seal with the middle rotating ring. Comparison and analysis between experimental results and calculation results show that: while the value of testing leakage rate is greater than the theoretical calculation, the testing value of leakage rate is within the allowed range. Therefore, it verifies the feasibility and reliability of the external driving mechanical seal.Combined with the basic theory of mechanical seal and TRIZ theory, mechanical seal with the middle rotating ring is proposed in the paper. When leakage is not exceeding the certain limits, it can adjust and control the relative speed of the end face, so as to get rid of the influence of the shaft in the seal. Thus it can significantly enhance the stability of the seal at work, and has high practical value.