Edward Clayton 
The presence of foreign contaminants in a hydraulic system can do more than just hamper its performance. Tiny debris particles can also wreak havoc on the machinery itself, ultimately leading to overheating, corrosion, and the risk of catastrophic equipment failure. For this reason, machines that depend on hydraulic systems to operate are outfitted with hydraulic filters, the nature of which can differ based on the machinery type and other factors.
In the following blog post, we’ll discuss the purpose and function of these critical components of hydraulic machinery. We’ll also explain the different types of hydraulic filters, with particular emphasis on which are the most commonly used and what applications they are best suited for.
Hydraulic Filters: The Basics
Hydraulic machinery operates by utilizing pressurized fluid to multiply the force applied to a given area. This allows equipment that utilizes hydraulic components to convey a great deal of power, making them ideal for heavy-duty machinery in the construction, automotive, and aviation industries, among many others.
Problems arise, however, when foreign contaminants are introduced to the hydraulic fluid in the system. There are many potential origins for these contaminants: They may be environmental, such as dirt, sand, or grime, or they may be from the machinery itself. For example, metal bits can flake off the larger equipment and end up in the hydraulic fluid, or debris can be introduced after the deterioration of rubber seals that are intended to prevent leaks from occurring.
Whatever their origin, particulate matter in a hydraulic system can cause serious issues with functionality, reducing its performance capabilities and damaging it over time. To improve efficiency, reduce repair costs, and extend the lifespan of equipment, a hydraulic filtration system must be installed. While there are many different types of hydraulic filters, they all ultimately serve the same purpose: to continuously capture and remove any contaminants before they can enter the machinery itself.
Choosing the Right Filter
Although they all have the same basic task, hydraulic filters are not interchangeable. There are many different types of hydraulic machinery, each with different specifications and, therefore, different needs with regard to filtration. To choose the correct filter for your machinery, a few critical details must be known.
For example, how sensitive is the equipment? Some machinery only requires larger particles to be removed. However, other equipment is highly sensitive to even the tiniest contaminants. For these, you may need a more advanced filtration system.
To get an idea of what type of filtration system your equipment needs, familiarize yourself with the ISO cleanliness codes for hydraulic fluids or speak with a technician. You can then ensure you purchase a filter that is correctly rated for your machinery.
Other details that matter when choosing a filter are the pressure levels of the system and its approximate flow rate. Familiarize yourself with your equipment and the different options to ensure your equipment remains in peak condition.
Suction Filters
Suction filters are among the most widely used types of hydraulic filters, largely due to their versatility and cost-effectiveness. They are usually connected directly to the pump on the hydraulic system, taking advantage of the suction that is generated as the equipment operates. The filter itself may or may not be installed within the fluid reservoir, depending on the type of machinery being used.
Suction filters utilize a mesh strainer to capture contaminant particles. Different strainer sizes are available depending on the required ISO cleanliness rating. Suction filters are effective as long as they do not interfere with the pressure in the hydraulic pump. If the removal of especially fine particles is necessary, different filtration technology may also be required.
Pressure Filters
While the purpose of suction filters is to remove contaminants before they are introduced to the system, pressure filters capture particles that have already been introduced to the system. Rather than being installed directly to the pump, they are usually installed somewhat downstream from it. The pressure of the system itself forces the fluid through the filter, allowing for the removal of unwanted materials.
Generally, pressure filters are better for removing smaller particles because they are at a lower risk of clogging than suction filters. They often utilize fine-grain silica to capture contaminants, making them excellent for systems that must be held to a higher standard of cleanliness.
Return Filters
Another option for filtration is to intercept particles as the fluid returns to the system, hence the name “return filter.” This type of system is preferable for an open-loop system, while pressure filters are best suited to closed-loop systems.
A return filter is usually mounted directly to the fluid tank itself, with a bypass valve installed to relieve pressure if too many contaminants accumulate within the system.
Return filters are excellent for larger-scale equipment, frequently being utilized in the construction industry.
Where to Get the Ideal Hydraulic Filters
The filtration systems listed above are the primary methods for filtering contaminants out of a hydraulic system. Choosing the correct one, however, is only the beginning of maximizing the efficiency and extending the lifespan of your system. Just as it’s critical to choose a filter with the correct ISO cleanliness rating for your needs, it’s also necessary to invest in the best possible equipment. The correct filtration system won’t be especially effective if it’s not well-constructed in the first place.
When shopping for filtration technology, look for industries that specialize in high-end machinery parts, such as Aberdeen Dynamics. Well-made, properly installed filters will be able to stand up to the work that your machinery will subject them to. In turn, they will prevent the accumulation of dirt, grime, and contaminants, allowing your hydraulic systems to continue to operate at their highest level for as long as possible.
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