What must be considered when selecting hydraulic fluid?

When selecting hydraulic fluid, one of the most critical considerations is the viscosity and temperature characteristics. Viscosity refers to the fluid's resistance to flow, which influences how well it can transmit power within the hydraulic system. If the viscosity is too low, the fluid may not provide adequate lubrication or may lead to leaks; if it's too high, the fluid may not flow easily through the system, which can cause increased wear and potentially lead to pump failure.

Temperature characteristics are also vital, as hydraulic fluids should maintain their performance over the expected operating temperature range. The fluid needs to remain effective in both cold and hot conditions; otherwise, it may thicken or thin to a point where it no longer performs adequately, affecting the overall efficiency and safety of the hydraulic system.

Other considerations, although they may seem relevant, do not carry the same level of priority. For example, while cost is a factor, it shouldn't be the sole determinant, as savings on the fluid can result in higher maintenance or replacement costs down the line. Similarly, patent protection may be a concern for manufacturers but is less relevant from an operational standpoint for the end-user. The color of the fluid could be indicative of a specific characteristic or type but does not directly impact the functioning of the hydraulic