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Vane Pumps: No Oil? Not Accompanied By The Exit Pressure?

Almost all causes of failure of the    Vane Pumps    may be caused by the lack of pressure or no pressure at all. The China vane pump manufacturer, supplier & Zhejiang Yongling Hydraulic Machine Co , Ltd . explained:


1. Poor contact between the oil distribution plate and the end surface (fixed surface) of the casing, and there is a large amount of dirt in between, so that part of the pressure oil in the pressure chamber flows into the low-pressure area through the gap between the two, and the output flow is reduced. Disassemble and clean to make them close.



2. The mating end (sliding surface) of the oil distribution plate and the rotor is frayed, causing serious wear, large internal leakage, and insufficient output flow. You can use a thicker (not too thick) sandpaper to polish the high point of the fuzzing, and then use a fine abrasive cloth Remove dents and use after polishing.



3. The inner hole (inner curved surface) of the stator is frayed and worn. The top circle of the blade and the curved surface bracket of the stator hole scratch the groove and leak into the oil absorption area, resulting in insufficient output flow. The stator inner surface can be sanded with metallographic sandpaper.



4. The blade and rear drill assembly (pump core) is installed upside down



5. The pump body has casting defects such as pores, trachoma, shrinkage, etc., and was punctured, so that the high and low pressure chambers were locally connected and could not suck oil. At this time, the vane pump may be changed.



6. The axial gap is too large, that is, the thickness of the vane pump rotor is too different from the thickness of the stator and the depth of the vane pump body hole, or a paper cushion is added during repair to make the axial gap too large, the internal leakage is too large, and the internal leakage Increasing the output flow decreases.



7. The variable mechanism is incorrectly adjusted, or there is something wrong, and it can be handled as appropriate after the cause is identified.



8. The end face of the oil distribution plate is worn or grooved, the internal leakage is large, and the output flow is insufficient. Generally, the end face of the oil distribution plate must be ground.



9, the oil filter is clogged, or the filtration accuracy is too high, no oil or very little oil (depending on the degree of clogging), removable and washable.



10. The viscosity of hydraulic oil is too low, especially for small-capacity vane pumps. When the oil viscosity is too low or the oil temperature rises too high, the oil produced by the vane pump often cannot be loaded to rise to the required pressure. This is because the internal viscosity of the oil is too low and the internal leakage increases due to temperature rise.



11. For the pressure-limiting variable vane pump, when the pressure adjustment screw is not adjusted well, the flow rate will decrease significantly after the pressure limit is exceeded, and the pressure will be difficult to be higher after entering the system.



12. After the parts in the vane pump are worn, although the pressure can be increased at low temperature, but after the equipment is running for a period of time, the oil temperature rises, the internal leakage due to wear is large, and the pressure loss is also large. (Can't reach the highest point). If you want to adjust it hard at this time (tighten the relief valve), the hand will shake violently. At this time, it is certain that the vane pump is seriously worn. If you replace it with a new vane pump, the pressure will rise immediately.



13. The inner surface of the stator is scratched, resulting in poor contact between the top of the blade and the inner curved surface of the stator, large internal leakage, reduced flow and difficult to adjust the pressure. At this time, the curved surface of the stator should be polished or the stator should be replaced.



14. For medium and high pressure vane pumps equipped with a pressure reducing valve, if the output pressure of the pressure reducing valve is adjusted too high, it will cause early wear of the top of the blade and the inner surface of the stator due to excessive contact stress. The leakage in the vane pump is large, the output flow is reduced, and the pressure cannot be increased.



Zhejiang Yongling Hydraulic Machine Co , Ltd  is a large-scale high-performance hydraulic vane pump manufacturer in China. Our products have won a good reputation in China with their stable and reliable quality, and applied to the torch tower of the 2010 Asian Games. Our products occupy most of the domestic market and are exported to Southeast Asia, Russia, Africa and other foreign markets.


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