1, the mechanical impurities in the oil or oxidation precipitated colloid, bitumen, carbon slag and other dirt piled up in the throttle gap. 1, the mechanical impurities in the oil or oxidation precipitated colloid, bitumen, carbon slag and other dirt piled up in the throttle gap.
2, because the oil aging or extrusion after the production of charged polarization molecules, and throttling gap on the metal surface there is a potential difference, so the polarization molecules are adsorbed to the surface of the gap, the formation of a firm boundary adsorption layer, the thickness of the adsorption layer is generally 5~8 micron, thus affecting the size of the throttle gap. When the above accumulation, adsorption growth to a certain thickness, will be washed away by the liquid flow, and then re-attached to the valve mouth.
As a result of this cycle, the flow of the pulse.
3, Valve mouth pressure difference is large, because the valve mouth temperature is high, the degree of liquid compression is enhanced, the metal surface is also more susceptible to friction and the formation of potential difference, so the pressure difference is easy to produce blockage phenomenon.