hydraulic power units
Hydraulic Power Pack comes in all shapes and sizes, flow rates, pressures, colors, and complexity levels. The purpose of these units can also vary, so below we will list the main components you can find, while accepting that some will have all of them and some will have only a few.
Reservoir
Hydraulic reservoirs come in a variety of shapes, sizes, and materials. To keep the fluid clean, they should be sized to allow fluid to settle in the tank, but recirculate enough to maintain a stable temperature. Additionally, they must be sized to handle actuator drain down volumes and work volume changes without becoming too small.
Baffle plate
A reservoir baffle plate separates the return and supply lines, allowing dirt and air to settle before reuse.
Tank access cover
An access cover is required for cleaning and maintaining hydraulic reservoirs. As they are typically located on the side of the reservoir, users cannot leave them open or use them to add fluid.
Air Breather
Air breathers are always required to compensate for changes in fluid volume, such as maintaining a constant pressure above the fluid head. To prevent dirt ingress, air entering the reservoir must pass through a filter that is as fine as or finer than the main system filters. Filling a hydraulic system through the air breather is not recommended, but if this is the only option, new fluid
Suction line
The pump inlet line is a large diameter, short pipe that pulls fluid from the reservoir and feeds it into the pump. Its size is critical for maintaining a low fluid velocity and thus as much positive head at the pump as possible. Flexible pipes are frequently used to isolate pump vibration from the tank.
Suction filter
Suction filters can improve supply conditions, but they can also be dangerous if not checked and maintained on a regular basis, as they can restrict pump supply.
Hydraulic Pump
Supply flow to the circuit from a fixed or variable displacement pump. Depending on budget and performance, gear, vane, or piston designs are typically used. More information can be found in our pumps section. Pumps will almost certainly be mounted on rubber mountings to isolate them from the reservoir and reduce noise radiation.
Case drain line
Some pumps require case drain lines that must be properly sized in order to keep case pressures within the manufacturer's limits. They also enable fluid priming of the pumps prior to
Bell housing and Coupling
To accommodate any misalignment or vibration, a flexible drive coupling is required between the pump and motor. Because most pumps cannot accept side loads and some even move slightly with pressure, rigid location is not allowed.
Electric motor
Electric motors are sized to provide maximum pump input power while also providing a suitable safety margin. To reduce overall energy consumption, modern, energy-efficient designs should be used.
Pressure Hose
Between the pump and the first component in the circuit, a short flexible hose is commonly used. This reduces noise and vibration while allowing the pumps to move on their AV
Pressure test point and gauges
A pressure gauge and/or test points are recommended for safety and maintenance. These allow operators to quickly assess the state of the power unit and are essential during commissioning and maintenance.
Pressure filter
Over 80% of all failures are caused by contamination. A pressure filter reduces the likelihood of contamination reaching circuit components, and if fluid passes through it several times, it should eventually prevent all contamination from reaching the components. Filters frequently include a bypass valve to prevent filter damage during cold start or near the end of their life. A variety of clogging indicators are available to indicate when the filter elements need to be replaced.
Relief valve
Relief valves are required to protect the system from overpressure and potentially dangerous failures. They can also be used to unload the system before starting or stopping the pump.
Isolation ball valve
Isolation valves protect workers during maintenance by preventing fluid from escaping the reservoir when items are changed or removed. These valves are frequently lockable, preventing people from opening them and pressurising the system after the maintenance engineer has closed them for maintenance.
Filling point
To ensure that the fluid is as clean as possible, filling points should be used to pump new fluid into the reservoir and through the return line filter.
Return line filter
Return line filters are used to remove contamination that has entered the system through cylinder rods and other means. Because low-pressure filters are less expensive than high-pressure filters, they are frequently used as the system's main cleaning workhorse with the highest filtration rating. Low-pressure return line filters also include a bypass and a visual or electrical clogging indicator to alert you when elements need to be replaced.
Anti-syphon valve
Anti-syphon valves are used to prevent fluid backflow when circuit valves are removed for maintenance. Without them, simply removing one valve may drain all of the fluid
Sight level gauge
Sight level gauges display the volume of fluid in the reservoir and are useful for detecting problems or leakage early on. Isolator valves are built into some level gauges. Because the glass is a potential failure point, isolating the display ensures that you can continue working even if the glass breaks.
Level switch
Level switches can provide remote, visual, or electrical warnings of low fluid levels, as well as a pump cut-out with extremely low fluid levels or a warning at high fluid levels.
Temperature switch
Temperature warning and cut-off switches can be provided to ensure that the system does not operate beyond its design parameters.
Immersion Heaters
Fluid immersion heaters frequently include thermostats to ensure that the fluid remains above its minimum working temperature. This may be necessary prior to starting the pumps. Details can be found in your operating
Cooler
Return line or offline coolers keep the tank temperature from rising above the system's design limits. These can be as simple as an inline filter located after the return filters or as part of a completely separate fluid conditioning circuit that removes fluid from the reservoir before pumping it back in clean and at the proper temperature.
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