Hydraulic Reservoir Overview
Fluid power systems require a consistent supply of cool, uncontaminated fluid for efficient operation.
In a hydraulic system, there is a reserve of fluid in addition to what is found in other components. This reserve compensates for fluctuations in fluid levels due to system operation, as well as losses from cooling and fluid compression under pressure. This additional fluid is stored in a tank commonly referred to as a hydraulic reservoir, although it may also be known as a sump tank, service tank, operating tank, supply tank, or base tank.
Beyond serving as a storage space for reserve fluid, the reservoir functions as a radiator to dissipate heat. It acts as a settling tank where heavier contaminants can settle at the bottom until they are removed through cleaning or flushing. Additionally, the reservoir allows for the separation of entrained air from the fluid.
Typically, reservoirs are equipped with a capped opening for filling, an air vent, an oil level indicator or dipstick, a return line connection, a pump inlet or suction line connection, a drain line connection, and a drain plug. Well-designed reservoirs feature internal baffles that minimize excessive sloshing and create a partition between the fluid return line and the pump suction line. This design compels the returning fluid to travel a longer route around the tank before being drawn back through the pump inlet line, which helps cool the fluid, aids in contaminant settling, and facilitates air separation. Larger reservoirs enhance these benefits further.
There are two main types of Automotive Lift Repair Tampa Florida reservoirs: non-pressurized and pressurized. Propower manufactures both types, with pressurized reservoirs operating up to 5 psi. Most systems are designed for operation at normal atmospheric pressure, suitable for both truck and stationary applications. Typical industrial reservoirs are constructed from hot-rolled steel plates with welded seams and are generally not intended for mobile use. These reservoirs often have a convex bottom and incorporate a drain plug at the lowest point.
Most non-pressurized Automotive Lift Repair Tampa Florida reservoirs are cylindrical and made from durable, corrosion-resistant metal. To maintain fluid cleanliness, filter elements are typically installed within the reservoir or externally to clean the returning fluid. Reservoirs that are filled by pouring liquid directly into them feature a strainer in the filler well to filter out impurities. Fluid levels in the reservoir can be monitored via a direct reading sight gauge, a clear tube, or a float/dial gauge.
First, assuming our new hydraulic fluid is free of particulate contamination (which is not always guaranteed), the reservoir should have a filter on the fill line to prevent any contamination during the filling process. Additionally, an air breather cap is essential for pressure relief as fluid levels fluctuate. This cap should be designed to prevent the introduction of particulate matter and moisture (including condensation) from the air. In essence, we should aim for a sealed system to minimize contamination. Some Automotive Lift Repair Tampa Florida systems are engineered to be completely sealed with a pressurized reservoir; regardless of the design, the objective is to eliminate all potential external contaminants.
Next, we need to address the reduction of internally generated contaminants, primarily wear debris. This is typically achieved with a filter on the suction line from the reservoir to the pump, ensuring protection for the pump and downstream components. The suction line should be strategically located and sized to prevent pump cavitation. Moreover, it should be positioned within the reservoir to minimize exposure to contaminants, turbulence, and hot fluid with entrained air (foam) that can come from the return line. This usually involves placing the suction line several inches above the bottom of the reservoir and away from the return line, often with an inlet filter.
As the Automotive Lift Repair Tampa Florida reservoir’s primary function is to store fluid, it should be equipped with a level gauge. This could be a simple sight glass or a more sophisticated float switch that maintains fluid levels within specified limits. Additionally, an alarm system should be in place to alert users if those limits are exceeded due to a leak or overfilling.
Lastly, the reservoir must include a drain and access port for cleaning and maintenance. Generally, contamination is the leading cause of hydraulic system failure. Thus, a well-designed, properly operated, and maintained reservoir is essential for controlling contamination within the system.
If you have a hydraulic system, you definitely have a reservoir. Even systems marketed as “reservoir-less” still need an expansion tank to accommodate excess fluid. Beyond these unconventional setups, hydraulic reservoirs provide advantages that extend beyond merely storing fluid. Your hydraulic machinery wouldn’t operate at its optimal level without the benefits that a reservoir brings.
When designing a hydraulic reservoir, it’s important to maximize its capabilities, particularly its size. The chosen size of the Automotive Lift Repair Tampa Florida reservoir greatly influences its performance parameters. Instead of focusing solely on the dimensions of the reservoir, think in terms of time. A larger reservoir essentially grants you more time. But time for what?
Manage Heat Generation
In many respects, a hydraulic reservoir acts as a buffer. The fluid returning from hydraulic systems often fails to meet the standards for healthy operation—it tends to be hot, contaminated, and potentially aerated.
Heat generation in Automotive Lift Repair Tampa Florida hydraulic systems is nearly unavoidable. Any energy input that doesn’t translate into useful work simply turns into heat, along with a small amount of noise. If heat is allowed to circulate unchecked within the system, it can lead to damage to pumps, valves, actuators, seals, and even the fluid itself over time.
To mitigate the harmful effects of heat on your Automotive Lift Repair Tampa Florida hydraulic components, a larger reservoir volume offers two clear benefits, plus one that might be less obvious. The greater the volume of fluid in your reservoir, the longer it takes for those heated molecules to re-enter the system and pick up additional heat along the way. This concept is known as dwell time, which is calculated as the reservoir’s volume divided by the pump’s flow rate. For instance, with a pump flow of 10 gallons per minute (gpm) passing through a fifty-gallon reservoir, the fluid’s volume will be exchanged every five minutes.