Choosing Hydraulic Tanks

How To Choose Hydraulic Tanks

Sometimes referred to as reservoirs, hydraulic tanks play an important role in supplying the hydraulic system with fluid.

From dissipating heat through the walls of the tank to conditioning the hydraulic fluid to help settle contaminants for improved fluid quality, the reservoirs perform several important functions.

To promote efficiency and high levels of performance, you need a suitable reservoir.

hydraulic tank

The reservoir can also foster a longer lifespan for various system components.

For instance, a certain amount of stored fluid could provide an effective way to settle water, sludge, and various other contaminants whilst enhancing the fluid’s suitability to perform its intended functions. They also particularly useful in removing air trapped or absorbed by the fluid itself.

Choosing the Right Size of Hydraulic Tank

You can choose from a wide selection of hydraulic tanks to meet your reservoir needs.

However, you need to understand your system requirements and specifications.

A specialist or technician could help you pick the perfect model for your system.

When considering the size of a hydraulic reservoir, the belief is that the bigger the size the better. This is mostly because the larger the volume of the tank the longer the oil dwell time, which ideally refers to the time the oil has to drop contaminants such as air, water, and particles. Indeed, size does matter.

When it comes to reservoir size, the rules of thumb differ for both closed and open circuits.

Open circuit conventional reservoirs should have a tank capacity of about 3-5 times pump flow-rate per minute, including a ten percent air cushion.

While these ideals are generally easy to attain when using a stationary hydraulic machine, particularly within an industrial setting, this is much harder to achieve in a mobile application because of weight and space restrictions. Therefore, 1.5-2 times the rate of pump flow tends to be a more logical setting for mobile applications.

While the reservoir sizing described above applies to open circuit systems, closed circuits require different sizing specifications. A tank volume of 3-5 times the pump flow rate would be considered as overkill for a closed circuit system, as that is not the actual flow rate passing through the tank, but ideally circulating in the loop (from transmission pump to motor and eventually back to pump).

A hydrostatic transmission features an open circuit charge pump.

Therefore, a charge pump flow rate of 3-5 times per minute can be ideal. For instance, a transmission pump of 100 gallons/ minute flow rate may require that the charge pump has a flow rate of 20 percent (at least 20 gallons a minute).

Following the 3-5 times rule, this would translate to a 60 to 100-gallon tank volume. In a mobile setting, however, a 1-2 charge pump flow rate a minute would perhaps be more realistic.

In the modern world, the non-conventional reservoir designs allow stored oil volumes that are smaller, thereby allowing shorter dwell times whilst ensuring that the release of air from the hydraulic oil is not compromised.

In contrast, when handling conventional reservoirs, cutting back on the amount of stored oil might cause reliability issues.

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