What is EHC fluid?
Hydraulic oils used in steam turbine electro-hydraulic control systems (EHC) are required to be fire resistant. These fluids may also be considered as Fill-for-Life fluids, meaning that they have the potential to last the life your steam turbine. Understanding how these fluids fail is critical.
What is the color identification of phosphate ester based fluid?
Skydrol is made of a fire-resistant phosphate ester base stock, with a number of oil additives dissolved into it to inhibit corrosion and prevent erosion damage to servo valves. It also includes a purple or green dye to ease identification.
How do you test hydraulic oil contamination?
Hold a small flame under the foil/spoon/container containing the fluid. If moisture is present then the fluid will crackle and pop as soon as it is heated up. On-site analysis using the above methods will not determine the actual content of water, only if water is present.
What are the 3 types of hydraulic fluid and their color?
Basic hydraulic fluid is amber. Brake fluids can be dyed red (common) or green (less common). Most US military fluid (23699, I believe) is red, but Skydrol (fire resistant aero hydraulic fluid) is purple. Generally, I believe the fluid is dyed so it isn’t mistaken for the wrong fluid.
What are the three types of hydraulic fluid?
Three common varieties of hydraulic fluids found on the market today are petroleum-based, water-based and synthetics.
- Petroleum-based or mineral-based fluids are the most widely used fluids today.
- Water-based fluids are used for fire-resistance due to their high-water content.
How do you read a hydraulic oil analysis?
Check with your lab to see what it offers for ferrous density. In general, iron in a hydraulic system is likely coming from the pump or cylinders. The precise source and cause must be identified.
What are the two general contaminants in a hydraulic fluid?
Contamination in hydraulic systems can be classified into particle contaminants (Metal particles from wear, dirt ingression) or chemical contaminants (water, air, heat, etc).
What is the unit of viscosity?
The unit of viscosity is newton-second per square metre, which is usually expressed as pascal-second in SI units.
Why is hydraulic oil Green?
A color change in hydraulic oil is a good reason to be alert but not a good reason to go running for the oil skid to replace it right away. The two most common causes of oil darkening are thermal stress and oxidation, neither of which will necessarily require that the oil be replaced.
What is the viscosity of hydraulic fluid?
between 10 and 100 mm²/sec
The viscosity of a hydraulic fluid is a critical element in the transfer of hydraulic power. The ideal viscosity range for a fluid—and thus its highest efficiency—is usually between 10 and 100 mm²/sec, depending on the application.
How do you test the quality of EHC fluid?
Regular fluid sampling and analysis is the best way to make sure the EHC fluid is within acceptable limits for particulate count, water content and acidity. The limits for particulate count will be dictated by the components used in the system, typically the servo valves, pumps and other valves.
What are phosphate ester electro-hydraulic control (EHC) fluids?
What are phosphate ester electro-hydraulic control (EHC) Fluids? Phosphate ester fire-resistant fluids have been in use in the control systems of steam turbines for over 50 years. There were needed because of fires with mineral oils, the growing use of higher pressure systems, and the need for fewer fires with nuclear stations.
Why is pH important in an EHC system?
The pH (acidity) of the fluid is also a critical parameter, if the pH is not within specification this can lead to advanced degradation of the fluid and EHC system components. Regular fluid sampling and analysis is the best way to make sure the EHC fluid is within acceptable limits for particulate count, water content and acidity.
What is the engine health charge (EHC)?
The EHC is the levy charged by first sellers and Original Equipment Manufacturers (OEM) on all oil fluid, oil containers and oil filters either sold to customers or used in initial fills of new equipment. This applies across all seven provincial associations.