This technical report aims to present the possible causes and the solutions for the problems in the unloading circuit of the hydraulic system as well as recommendation for the maintenance strategy the system. The problem are oil reservoir is too hot and the curing pressure in the system insufficient. This report consists of two main topics. Firstly, the technical topic, which has covered the possible causes and some recommendations to solve problems in the system. Secondly, the maintenance strategy, in this part of the report there will be two types of maintenance strategies, which are preventative and predictive maintenance strategies. Each type is related to specific piece of equipment required in this hydraulic system. …show more content…
The pressure and flow rate increase or decrease in discharge line depend on the demand of the system in normal process. Therefore, if the pressure filter is semi blocked (not fully blocked), the flow rate decrease at the orifice makes the pressure at pump will be increased and suddenly, the pressure decreases after pass the orifice. Schaschke (2005) stated that a drop in fluid pressure because the increase in the cross-section causes a reduction in velocity and an increase in pressure. The kinetic energy is decreased and the potential energy which is in a form of pressure will increase simultaneously then, they are converted to heat. Kinetic and potential energy can be converted into heat completely (Orr, Baker and Bent 2002). Consideration that the system is working under this situation continuously, there will be insufficient pressure because the pressure drops repeatedly after the area of semi blocked. In addition, the pressure drop will make the temperature gradually rises and at the end of system operation, the hot fluid will return and collect in the reservoir. However, this problem can be solved by replacing the filter, but it cannot be done prior to sure that problem by measure the pressure and flow rate before and after the filter in order to find out if the problem is there or not. If they show the different significant reading, that indicates to the problem, but if they are the same or similar, there is …show more content…
As the Unloading valve is pressure-control devices that are used to dump excess fluid to tank at little or no pressure, Therefore, if this valve does not work it is function probably, it will cause problem. For example, the two position direction valve remained in close position (no fluid flow to the tank) due to many factors such as no PLC signal received, pressure switch is out of order, blockage in the pilot line between the pressure switch and two position direction valve, pressure gauge does not present an accurate and right reading or some human errors in setting them. For the three position directional valve also can cause the problem if it is incapable of unloading due to not being in the central position in some cases such as faulty (broken spring) or worn. However, to sort these problems out periodically maintenance programme should be