At the beginning of this month, I received a call from an old customer in Foshan, Guangdong. It reported that a sewage suction truck purchased from me had malfunctioned and I did not know how to deal with it.
This customer's cleaning and suction truck was purchased from us in October 2019, using Dongfeng Tianjin chassis, Cummins 210 horsepower, and a total volume of about 13 cubic meters meters. Water distribution ring pump and attached engine.
After communicating with the customer through telephone and video to understand the situation, the fault phenomenon is that the vacuum pump shakes seriously when the vacuum pump is working, and the bearing bracket is broken. There are several possible reasons for the failure of the cleaning and suction truck:
1. The engine idling speed is too low and there is jitter, which drives the vacuum pump to jitter.
2. The working platform attached to the engine and the water ring pump is deformed, which causes the drive shaft of the attached engine and the vacuum pump to be out of concentricity and jitter during operation.
3. The drive shafts of the attached engine and the vacuum pump are not aligned before leaving the factory, and the drive shafts of the attached engine and vacuum pump are not concentric, causing jitter during operation.
First of all, the third reason can be ruled out, because the United Dredging Vehicle inspected the vehicle with the customer before leaving the factory, and no abnormal vibration or sound was found.
Second, check whether the working platform with engine and vacuum pump is deformed. Observed by the naked eye first, no obvious deformation was found. Using infrared detection, no deformation was found. The cause can be ruled out.
Excluding these two possibilities, the most likely cause of failure is that the engine idling speed is too low, causing jitter and driving the vacuum pump to jitter. Communicating with the customer on the phone again, the customer said that in order to reduce the fuel consumption of the attached engine, the idling speed of the attached engine was lowered by oneself. After the engine idling speed was lowered, the engine and the vacuum pump were shaking slowly.
The customer’s cleaning and suction truck is still within the warranty period, so a new bearing bracket was delivered to the customer free of charge to replace the old bracket that was broken, and the customer was asked to increase the idle speed of the attached engine. At this point, the fault is resolved, the sound is stable when cleaning the sewage suction truck, and the attached engine and water ring pump have no shaking.