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Thermal Oil Pump-Common Ways to Remove Breakdowns

Currently, CB-B type gear pumps are widely used in the dump truck and construction machinery, now Honghai Pumps explains the common faults and exclusion methods as below, for reference only.

1. Reasons of vibration and noise, and exclusion methods.

(1) Intake air

①As for CB-B type gear pump, the pump body and both sides cover is hard seal direct contact, if the flatness of the contact surfaces do not meet requirements, the pump easily inhaled air at work; Similarly, between the pump cover and the cap, which is also direct contact, the air is easily penetrated; if the lid is plastic, due to its damage or deformation due to temperature changes, the air is easy penetrated caused by leaky seal. 

To exclude this failure, the method is: when the flatness between the pump body and pump cover doesn’t meet the requirements specified, you can use emery to grind the plate back and forth by shape route, otherwise use grinding surface grinder to make flatness not more than 5 μm; for leakage between the cover and lid, it’s suggested to use an epoxy resin or other adhesive for sealing.

② Skeleton type sealing is generally used for the shaft seal. If the spring off, or the oil seal backward, or lips were strained, aging, all the above situations will make the rear end seal often in negative state , thus to intake air, a new seal should be replaced and the problem solved.

③ Not enough fuel in the tank, or the suction nozzle is not plugged in to the oil below the surface, the pump will draw air into the fuel tank and you should replenish oil to the oil marking; if the return pipe mouth exposed oil, sometimes due to the negative pressure within the system instantly leaving air anti-irrigation into the system, so the return line ports generally should be inserted into the oil below the surface.

④ Pump mounting position from the oil is too high, especially when the pump speed is reduced, because they can not ensure the pump suction cavity caused by lack of the necessary degree of vacuum suction and thus intake air. You should adjust the relative height of the pump and the oil so that it meets the requirements.

⑤ Oil filter is clogged dirt or capacity is too small, resulting in an increase in the intake air suction resistance; in addition, into the larger diameter oil port may also be brought into air. At this point, washable filter, or select a larger capacity, and the export path appropriate filter. In this way, it not only can prevent the inhalation of air, but also prevent the generation of noise.

There are other reasons like mechanism reason, heating or output flow problem, we will explain in our coming article.