Correctly understand the oil leakage phenomenon of shock absorber
In order to meet the application requirements of the function of the shock absorber itself, there is a thin oil film on the surface of the piston rod in the design of the shock absorber itself. These oil films will be scraped off by the dust lip on the oil seal of the shock absorber when the shock absorber is tightened. At the same time, a very small amount of oil will accumulate on the upper part of the oil seal. Due to the high permeability of this oil, the oil accumulated on the upper part of the oil seal will start to diffuse from the upper part of the shock absorber to the lower part, forming a thin oil film, which makes people mistake this situation as oil leakage, In practice, this situation does not affect the application.
Oil film: the key factor affecting the durability and smoothness of oil seal, the composition and scraping of oil film
When the piston rod extends, it forms an oil film. When the piston rod is pressed in, the oil film will remain outside the oil seal when it is scraped by the oil seal dust lip. In order to enable the dealer service providers to correctly understand the principle that the shock absorber will naturally form an oil film during normal operation, they can give the user a correct explanation. The oil leakage mechanism of shock absorber is discussed as follows:
Shock absorber oil leakage: because there are microcracks on the surface of the piston rod coating, the microcracks on the piston rod store a certain amount of damping oil to form an oil film, making the friction between the piston rod and the oil seal wet friction, thus improving the shock absorption performance of the pneumatic butterfly valve, and greatly extending the service life of the pneumatic butterfly valve. A small amount of oil leakage is a normal phenomenon. The composition of the oil film is a special design to ensure the function of the shock absorber and extend its service life.
The oil stain of ordinary oil leakage does not exceed the spring disc. The oil stain is limited to the lower spring disc from the oil seal of the pneumatic butterfly valve. It is normal oil leakage and cannot be considered as oil leakage. The design of oil filling volume in the ordinary shock absorber once considered the loss of oil leakage. When the shock absorber was consumed, the oil volume was filled according to the specification. When the normal loss of oil in the use process does not exceed 25ml, the shock absorber will not appear abnormal. The results of the bench durability test on the oil leaking shock absorber show that oil leakage will not constitute oil leakage even after driving 200000 km, After the experiment, the amount of synthetic oil is reduced by 5-20ml. The performance of the shock absorber meets the application requirements. Acoustic wave characteristics and noise reduction methods
A acoustic system is composed of three rings of sound source, transmission path and receiver. Therefore, noise control must be considered from these three aspects, not only to study it separately, but also to consider it comprehensively as a system.
B Suppress noise at the sound source, which is the most basic measure, that is, active disposal. It includes reducing the excitation force, reducing the response of each link of the system to the excitation force, and modifying the operation procedure or technological process.
C In the control of sound transmission, acoustic control is adopted, that is, passive disposal. This is a common technology in noise control, including sound insulation, sound absorption, noise elimination, damping and vibration reduction measures.

What is the content of measurement?
The measurement content of electromagnetic flowmeter can generally be summarized in the following six aspects: measurement unit and unit system: measurement instrument (or measuring instrument), including the realization or realization of measurement benchmark and measurement standard, working measurement instrument of measurement unit: large measurement value, tracking source, including verification, calibration, test, inspection and test: physical constant, Measurement of materials and material properties: measurement uncertainty, data processing, measurement theory and methods: measurement management, including measurement assurance and measurement supervision. The function of electromagnetic flowmeter is to produce uniform DC or AC magnetic field. The DC magnetic circuit is realized by permanent magnet, which has the advantage of simple structure and less interference from AC magnetic field, but it is easy to polarize the electrolyte liquid in the measuring tube, so that the positive electrode is surrounded by negative ions, and the negative electrode is surrounded by positive ions, that is, the polarization phenomenon of the electrode, and causes the internal resistance between the two electrodes to increase, thus seriously affecting the normal operation of the instrument. When the pipe diameter is large, the permanent magnet is also large, bulky and uneconomical. Therefore, the electromagnetic flowmeter generally uses an alternating magnetic field and is excited by a 50HZ power frequency power supply. Vortex flowmeter is characterized by small pressure loss, large range and high accuracy. It is almost unaffected by fluid density, pressure, temperature, viscosity and other parameters when measuring volume flow under working conditions. There are no movable mechanical parts, so the reliability is high and the maintenance is small. The instrument parameters can be stable for a long time. The vortex flowmeter adopts piezoelectric stress sensor, which has high reliability and can work in the operating temperature range of - 20 ℃~+250 ℃. With analog standard signal and digital pulse signal output, it is easy to use with computer and other digital systems. It is an advanced and ideal measuring instrument. The steam flowmeter is mainly used for flow measurement of steam medium fluid in industrial pipelines. The steam flowmeter is characterized by small pressure loss, large range and high accuracy. It is almost unaffected by fluid density, pressure, temperature, viscosity and other parameters when measuring the volume flow under working conditions. There are no movable mechanical parts, so the reliability is high and the maintenance is small. The instrument parameters can be stable for a long time.