This real-time simulation of a hydraulic power unit lets you enter your own operating conditions and then observe how the temperature can be stabilised by the introduction of off-line cooling. Calculations of power in, power out, cooling power and radiated heat loss are included.
The module also includes a clear demonstration of how contamination is continuously generated in any hydraulic circuit and how it can be removed with off-line filtration.
1 This is a real time simulation of a hydraulic power unit.
2 Click on the directional valve's solenoid to operate the valve.
3 Change the relief valve slider to adjust the pressure relief valve setting.
4 You can also enter new pressure and flow values directly into the edit boxes.
5 The power unit's temperature is shown on the temperature gauge.
6 The cooler thermostat switches automatically and the cooler circuit flow can be adjusted by the slide bar.
7 The input power is shown in the calculation on the right-hand side.
8 Operate the directional valves and change the cylinder load to observe its effect on the input power.
11 Work is only done by the system when the cylinder is moving upwards.
12 Adjust the cylinder size and mass and observe the effects on the output power.
13 The difference between the input and output power will be lost as heat, vibration or sound etc.
21 Increase the off-line circuit flow to increase the rate of cooling.
22 The cooler will only operate when the thermostat is activated and then allows water into the cooler.
23 Enter large flow values into the edit boxes to experience over-heating or over-cooling.
31 The volume of oil in the reservoir will affect the temperature rise and temperature drop rates.
32 The reservoir and pipework will radiate heat from their surface areas.
33 Change the reservoir size and surface area in the edit boxes to observe the effect.
41 All of the previous parameters work together to determine the total system heat balance.
42 Enter the data for your own system design to evaluate the heat performance.
43 Please note that these calculations are intended only as a guide and may not be suitable for all system designs.
51 When using a variable displacement pump the relief valve only provides a fixed maximum pressure.
52 The variable displacement pump reduces its displacement when no flow is required and therefore greatly reduces the energy usage.
53 Compare the heat balance of this system design with that of the previous fixed displacement pump system.
61 Over 90 percent of problems in hydraulic systems are caused by contamination.
62 Even new oil is not clean.
63 Contamination will continuously enter the system through air contact, actuator seals, and abrasion of any moving parts.
64 All systems must be suitably flushed prior to commissioning.
65 Operate the off-line circuit to remove the contamination with the filter.
66 The level of contamination ingress will depend on the hydraulic system's environment and duty.
67 Filter flow rates and element rating will affect the contamination removal efficiency.