How Temperature Affects Hydraulic Cylinders: Protecting Hydraulic Systems from Extreme Temperatures

Extreme temperatures drastically reduce the lifespan of hydraulic systems and impede their effective functioning. To protect hydraulic cylinders and other system components from damage, it is essential to be mindful of the effect of temperature on the viscosity of the hydraulic fluid.

Temperature extremes may cause decreasing or total lack of cylinder capability, malfunctioning components, and ultimately damage the system, resulting in unavoidable hydraulic repairs.

This article outlines the potential risks of hydraulic oil temperature extremes and offers advice on safeguarding against such damage.

How Low Temperatures Affect Hydraulic Fluid & Cylinders

Low temperatures produce several adverse effects on hydraulic cylinders:

• Increased viscosity of hydraulic fluid: When hydraulic fluid viscosity increases, it reduces the fluid’s flow speed, placing strain on the pumps. Increased exertion causes cavitation – when air bubbles form and collapse – leading to a loss of lubrication, corrosion, metal debris, and system failure. Low-temp hydraulic fluid can also cause the system to become unpredictable, accelerating the wear and tear of other components;
• Reduced seal performance: Low temperatures make seals brittle and less pliable, which induces cracking or shrinking and compromises the seal’s leak-proof abilities. If compromised seals are not repaired or replaced, moisture, grime, and air can enter the hydraulic fluid, leading to a system failure;
• Intensified condensation: Too much condensation causes corrosion inside the cylinder, build-up of moisture in the system, and blockage of the valves, all of which can reduce the system’s effectiveness;
• Induced brittleness: At low temperatures, the metal components in hydraulic cylinders become more brittle and prone to cracking or breaking. The more rigid the parts become, the more quickly they’re damaged. Continuous expansion and contraction also cause fatigue in metal materials such as aluminum, steel, and hydraulic hoses, which may lead to system failure.

The Effects of High Temperatures on Hydraulic Cylinders

Hydraulic pumps naturally generate heat when running. However, the temperature should never exceed 180 °F.

Extremely high temperatures have several detrimental effects on hydraulic systems:

• Seal failure: Seals, like hydraulic cylinders, work optimally between 110 to 130° F. Several properties, such as the durometer, abrasion, tear resistance, and lubricity, may change when heated above their specifications. These scenarios can lead to seal failure, resulting in oil leaking past the seals, system contamination, and metal-to-metal contact that can permanently damage cylinder components;
• Increased oxidation: At high temperatures, the oxidation of hydraulic fluid can produce undesirable byproducts. Accumulation of these byproducts, such as sludge and varnish, clogs hydraulic lines and valves, causing a decline in efficiency and performance and, in extreme cases, premature system failure. The chemical reaction rate increases twofold for every 10-degree increase in hydraulic fluid temperature. Therefore, the higher the hydraulic oil temperature, the faster the oxidation rate;
• Lubrication loss: A high-temperature hydraulic cylinder reduces oil viscosity. After a certain point, it’s no longer effective in protecting reciprocating cylinder parts. When oil is too hot, it accelerates mechanical wear, necessitating increased pump and cylinder replacements.

Pinpointing & Mitigating Heat Build-up in Hydraulic Systems

Reasons for Hydraulic System Overheating

Quickly identifying the cause of your hydraulic cylinder getting hot can prevent irreversible system damage.

A few of the most common reasons for hydraulic pump overheating include the following:

• Contaminated hydraulic fluid: If debris and dirt are inside the liquid, contaminated particles can accumulate and clog system filters. If this occurs, the pump has to use more energy to force the fluid through the filters, resulting in overheating;
• Aeration: Air leaks in your hydraulic system’s seal and connections can let air in, producing bubbles in the fluid. When these bubbles are compressed, they generate heat, raising the temperature;
• Low reservoir fluid: A low reservoir fluid level in a hydraulic system results in an inability to effectively dissipate heat, leading to rapid overheating and pressure instability;
• Blocked or damaged heat exchanger: This component is crucial to your hydraulic pump’s cooling system. If blocked or damaged, it cannot help correctly remove heat from your pump;
• Broken flow regulators: If the flow regulators are not operating correctly, insufficient amounts of fluid will travel through the system, causing a lack of lubrication and cooling, resulting in system overheating;
• Low-pressure levels: When the system pressure is too low, it can’t move heat away from working components.

How to Prevent Hydraulic System Temperature Extremes

You can prevent hydraulic cylinder equipment from failing by doing the following:

• Use the correct hydraulic fluids: Only use fluid designed for your specific hydraulic system;
• Keep the fluid clean and contaminant-free: Change the fluid regularly according to the manufacturer’s recommendations;
• Use a heat exchanger: A heat exchanger can help to dissipate heat from the hydraulic fluid and prevent it from getting too hot;
• Inspect the system regularly for leaks: Check it regularly and repair leaks immediately;
• Don’t overload the system: Always operate it within its design limits;
• Use a cooling system: If your hydraulic system works in a hot environment, you may need a cooling system to help dissipate excessive heat.

Professional Hydraulic System Repair and Maintenance Services

While controlling external environmental temperatures is impossible, regular inspections and maintenance keep your hydraulic systems in good working order.

Using the correct fluid and investing in a cooling system is also helpful. By taking the steps needed to manage temperature extremes, your hydraulic cylinder will remain in optimal condition and require fewer repairs.

However, Cylinders, Inc. is always ready to help if you need urgent repairs or troubleshooting. Call us for all your hydraulic cylinder servicing needs!