Selecting the correct hydraulic oil for your hydraulic system can be a little challenging, since there are a variety of options available. Most hydraulic systems can use several different oils, so it’s a matter of choosing the best one for your particular system.
If you do use the wrong oil, chances are you won’t notice immediately. It won’t cause an explosion or anything too obvious, but it will shorten the lifespan of your system’s parts. Anything that requires lubricant will not work as efficiently with the incorrect lubricant. There will be more wear and tear when the lubricant is too thin and the entire system will need to work harder if the lubricant is too thick.
You may also notice that the hydraulic system puts out more heat than normal when it has the incorrect lubricant and there will be more sludge and corrosion within the system, as well.
To avoid this problem and ensure that your components stay in great condition for as long as possible, you’ll need to select the best hydraulic oil.
Hydraulic System Oils: What You Need to Know
With so many different factors to consider, you should be sure you understand what the various oils include.
The main factor when choosing an oil is the viscosity or how thick the oil is in specific conditions. If you select the wrong viscosity grade for your system, you’ll find that your hydraulic system doesn’t work very efficiently.
Ideally, you want to match the viscosity grade to the operating temperature of your system. The right viscosity will help the system dissipate heat, release air, and aids in mechanical and volumetric efficiency.
In general, the higher the operating temperature, the lower the viscosity of the hydraulic oil, as it heats up and becomes thinner. This is why it’s important to select an oil that is meant for the operating temperature of the system, so it will provide the perfect level of lubrication.
You should also consider the additives in the oil. There are a number of things that can be added, which will make it more or less useful depending on the hydraulic equipment. There are two main types that are added to give the oil anti-wear properties. These create a very thin layer on the metal surfaces to prevent them from touching each other.
ZDDP or Zn based additives are the most often used additives. However, there are Zn free additives that are much better for the environment, as well as useful in situations where there are corrosion issues that will be made worse with Zn based additives.
You may also add a rust inhibitor, which will coat the metal and prevent corrosion from water.
Oil mixes with O2 and can create by-products that are fairly acidic. These will create oxidation, so you want to look for oil that will stay fairly stable even at high temperatures. The oxidation will be affected by water and wear metals, as well as the temperature.
The oil needs to have the ability to release any air that is captured. Since it is being forced into a small space, air bubbles are likely to form and this needs to be dealt with. As the hydraulic system works, the air should be released. Any air in the system will cause cavitation and poor efficiency.
The oil will also need to release water, which may be added to the oil via humidity in the air. Since this can affect the entire system and cause rust and corrosion, you should be aware of this potential issue. Select an oil known for releasing water. If water is an issue, you should also consider adding a rust inhibitor.
Can the oil be sent through a filter to reduce particles and contaminants? It’s nearly inevitable that some contaminants will get in, but if you’re working in the field with a rubbish lorry or an excavator, where dirt is just part of the job, it’s even more likely. Filtering will help the oil stay usable for longer.
It’s also important to select hydraulic oil that will not deteriorate the seals or other plastic or rubber materials. Be careful to choose one that is not only rated for your system’s thermal output, but for the parts that your system uses. You’ll want to avoid any further damage, once you’ve selected the right oil.
It may sound a little complicated to choose hydraulic oil, but it’s mostly common sense. Your machinery should come with a suggestion for lubricants and you can also talk to a qualified hydraulic service to find out just what to expect and which would be the best option for your particular system. They can make a suggestion, based on extensive knowledge, to keep your machinery running properly.
Hydraulic Cylinders and Equipment
Hydraulic systems are more common than you might realise. They’re used for industrial uses above all, but can also be found in a variety of other areas. If there is linear motion involved, then hydraulic systems can often be used.
They are used in many industrial settings, as well as factories and large machinery.
The Hydraulic Cylinder
The most important part of a hydraulic system is the cylinder. This is essentially a metal tube that had a cap at either end. On one end, a rod stick out of the cap and this connects to the piston inside the cylinder.
To make it work, fluid is pushed into either side of the cylinder, causing the piston to push further into the cylinder, or to be pushed out, extending or retracting.
The cylinder is connected to whatever part of the machine needs to move, such as an excavator arm, and is used to control this movement. When it comes to industrial uses, the cylinders are usually either tie rod cylinders or welded body cylinders.
Tie rod cylinders are extremely sturdy and can handle some heavy usage. You’ll find these most often in factories. They use tie rods, or very strong steel rods that are threaded through the two end caps to hold the caps to the cylinder. In small cylinders, you’ll only have four tie rods, but the larger options require up to 20 tie rods to hold everything in place.
Welded body cylinders simply weld the caps to the cylinder, with the rod gland bolted in for easy removal. These types of cylinders tend to be more streamlined than tie rod cylinders and are easier to customise, as needed. These are most commonly found in construction equipment and cranes, or other heavy industry applications.
If you have used the wrong hydraulic oil in the past, you’ll find that your equipment needs repair more often than usual. As parts wear out from the lack of lubrication, you’ll need to replace them. However, if you can use the correct oil in the future, you’ll find that the parts you replace will last much longer and should stay in better condition than the other parts, since it will be properly maintained.
In order to repair the hydraulic system, you’ll need to take the entire thing apart in most cases. The systems are relatively simple, compared to electronic options and if there is a problem, it can usually be found during disassembly. If you’re doing this yourself, be sure to do it on a clear, open space, so you won’t lose your parts.
The hydraulic fluid will need to be drained, then the pieces can be taken apart and it should be easy to see any damage to the system. You may find that a hydraulic cylinder is bent or there may be scratches inside the system. It’s also important to look at the seals and ensure they are all secure. Often, the seals will be replaced simply as a precaution. You can also replace any damaged parts and ensure that they are properly positioned, so as to avoid any potential issues.
To reassemble the hydraulic system, everything should be carefully dried, new seals applied and put it all back together. The piston will be the final part placed.
You can learn to do your own hydraulic repair, but it’s usually simplest to call in an expert. It’s also important to get an expert to handle the repairs if there are multiple parts that need to be replaced. It can get complicated if you are trying to replace or repair too many pieces and you could end up doing more damage to the system in the long run.
If you have someone who can come in and quickly repair or replace the part, you’ll find it is a more efficient method of getting things done. You’ll be up and running again in record time.
If you’re looking for a little help with your hydraulic system maintenance, contact HP Hydraulics for a quote.