The issue of abnormal temperature is one of the most common and concealed failures in the hydraulic system. It affects the service time, production efficiency and maintain cost of devices directly. This article will explain how temperature affects hydraulic systems and what we can do to prevent these issues.
Sensitive Components to Temperature
Temperature variations have a significant impact on some certain components within hydraulic systems. Some metal components, seals, O-rings, pipes, and other parts may be varying degrees of hardening, brittle or expansion under extreme low or high temperature conditions. This will impact the normal operation of hydraulic systems.
Fluids viscosity changes caused by temperature can also affect the operation of hydraulic pumps and motors. Low temperatures increase the viscosity of fluids, while high temperatures decrease it. The change of fluid also indirectly affects other components. For example, hydraulic valves may become clogged or corroded due to fluid viscosity, leading to leakage issues.
Effects of Cold on Hydraulic Systems
Delayed Startup
The issue of low temperature may be not obvious, but it can cause a serious malfunction during the startup and early operation of devices. The hydraulic system requires a long time to pre-heat in low temperature conditions, and cylinders, valves, or other components respond slowly. When the device starts, it takes a long time to idle running to reach the normal work condition.
Fluid
Low temperature is easy to make the fluid solidify, which can significantly increase the viscosity of fluid and impact the fluidity of the fluid. Too high viscosity fluid will bring excessive loads to the motors, and make them work slowly or cannot start, then increasing pressure of the system. Hydraulic pumps and valves may also be contaminated by the fluid, leading to wear or damage.
Brittleness
Low temperature can significantly affect the seals, especially the thermal elastomers or the seals that are made of rubber. With the temperature decreasing, the seals are more brittle and lose their performance, leading to fluid leakage. Due to the low temperature shock or pressure fluctuating, seals are easy to fracture. Broken seal fragments entering the fluid may cause a secondary solution, damaging other components.
Intensified Condensation
Condensation is a common phenomenon in low temperature environment, but it is harmful for hydraulic system. The moisture bring a serious corrosion to cylinders, and clog the valves. This significantly decreases the effectiveness of hydraulic systems.
Pressure Fluctuations
In the low temperature condition, insufficient flow ability of fluids makes uneven pressure distribution in hydraulic systems. If hydraulic control valves are stock due to low temperature and cannot adjust pressure and flow in time, the system will come about sudden pressure fluctuations or stock. This process may be a potential threat for equipment safety.
Effects of High Temperature on Hydraulic Systems
Viscosity Reduction
When the temperature is too high, the fluid will become excessively thin and it is difficult to form a stable oil film between hydraulic valves, pumps and cylinders. This phenomenon leads to decrease the lubrication of metal components, and make them contact directly, which can accelerate wear. Too thin fluids can also cause leakage or impact pressure stability, reducing system efficiency.
Oxidation Acceleration
Hydraulic fluids are easy to oxidize in high temperature environments. This not only shortens service life of fluids, but also produces sludge and deposits within the system, which may clog valve spools and filter elements. The replacement period of fluids in high temperature condition is usually reduced significantly, it will increase your operational costs.
Seal Degradation
Hydraulic seals are often made by rubber or other polymer materials, so heating can accelerate their aging process. In a high temperature environment, the seals are easy to harden or expand, leading to fluid leakage and increased losses.
System Instability
High temperatures directly impact the control precision and pressure stability of the hydraulic system. If the viscosity of fluids is too low or the valve spools are stock, the pressure may be unstable and increase fluid leak. Unstable pressure will trigger system shocks, make the control valves fail to respond correctly, cause equipment damage and personal injury.
Increased Energy Consumption
High temperatures reduce the overall efficiency of the hydraulic system. It means the devices have to consume more energy to keep normal operation. The high load state may accelerate components wear and fatigue, increasing the load of hydraulic pumps and motors, which significantly improve power consumption. If the lifespan of these components is shortened, your maintenance cost will increase.
Signs of Temperature Issues in the Hydraulic System
Issues caused by temperature are not easy to find, but there are some signs to remind you. The followings for your reference:
When the temperature has some effects on hydraulic systems, you can possibly notice that the response time of hydraulic systems becomes slower. For example, the startup time is prolonged, working efficiency is slow or the performances are weakened. Sometimes there is abnormal noise on the system.
Components wearing is also an important sign. Harden or cracked seals, hydraulic pumps or valves damage, and other failures all remind you that your hydraulic system may have issues. If severe, it will cause leakage problems.
High temperature issues mainly reflect in fluids. If the fluid has a too dark color or a burning smell, it means the hydraulic system is overheating. This can indirectly cause system malfunctions, leading to frequent shutdown. Excessively high temperatures can also accelerate oxidation of the fluid, producing contaminants.
How to Prevent Temperature Issues
Install Cooling Systems
Installing a cooling system can adjust temperatures when the system overheats, decreasing the effects of high temperature. Devices such as heat exchangers or cooling fans can be used for your hydraulic system. The cooling system can ensure a stable temperature, and help the fluid maintain a proper viscosity to increase the operating efficiency of the system.
Proper Hydraulic Fluids
When choosing hydraulic fluid types, you should consider their viscosity, performances and other factors. It is better to use compatible fluids with the hydraulic system. Some fluids may add VI(viscosity index) improvers or other active ingredients, it can extend the service life of components and decrease temperature impacts.
Protective Enclosures
If your hydraulic system has to work in extreme conditions, installing a protective enclosure will keep the system safe, and minimize impact with the environment. Constructing protective shells for some sensitive components such as seals, cylinders, hoses and valves can protect them effectively, and extend their service time.
Regular Monitoring and Maintenance
Routine monitoring and maintenance is also an important method to keep the hydraulic system running safely. You can install temperature sensors, pressure gauges, or other devices in your hydraulic system to periodically check if the numbers are normal. Keeping proper viscosity and cleanliness of fluids, and repairing or replacing the worn components in time.
Conclusion
The impact of temperature changes on hydraulic systems cannot be overlooked. In severe cases, it can cause the entire system failure. So, you should take preventive and maintenance measures. If you want to learn more about the hydraulic system, please feel free to contact us for professional solutions and recommendations.
FAQ
1. What are the reasons for the hydraulic system overheating?
If the hydraulic system works near a heat source or in a poor ventilation area, it may be overheating. But the hydraulic system overheating is not only caused by environments, the internal system failure is also a factor. If lubrication of the hydraulic system components is not sufficient, it will generate significant friction, which can lead to excessive internal temperatures. The condition of seals, fluid viscosity, flow velocity, and flow rate also affect the internal temperature of the system.
2. How does the temperature affect fluid viscosity?
High temperature will decrease the viscosity of fluids, causing leakage or components damage. While cold temperatures can increase the viscosity. Low temperatures are possible to meet the condensation point of the fluid, make the fluid tend to be solidified, and increase the friction. But it can also cause a slow response of the hydraulic system, increasing energy consumption. When the temperature increases by 9℃, the fluid viscosity will reduce by half. Conversely, if the temperature drops by 9°C, the viscosity doubles.
