Comparison of Hydraulic and Industrial Filtration Systems

 

Filtration equipment designed for hydraulic systems are sometimes used for industrial liquid filtration applications and likewise there are overlaps in applications for industrial filtration equipment within hydraulic systems. Both types of filters remove contaminants from liquids, however they are designed with different priorities and considerations based on the specific needs of hydraulic systems and industrial processes.

Typical examples of hydraulic systems which require the specialized hydraulic filter designs include:

 

1.  Hydraulically actuated machinery (presses, molding machines, and robotics)

2. Lubrication systems (gearboxes, turbines, rotating machinery, and hydraulic systems)

3. Cooling systems (circulation of a heat transfer liquid through heat exchangers)

 

In all cases the purpose is to protect equipment from contaminants fouling, damaging or impeding the performance of downstream processes.

Industrial filtration equipment generally has a broader application base, having configurations adaptable to different viscosities, temperatures and much higher flow rates than applicable to hydraulic systems. The area of overlap, where industrial filtration utilized for hydraulic liquids are typically for preconditioning or waste filtration. Initial filling of hydraulic systems, including transfer from tankers and into/out of barrels, often involve a coarse level of filtration to remove particulates that are accidently introduced into the liquid.

When the hydraulic liquid is worn out or replaced, it is often recovered and filtered for recycling or disposal, which could entail using industrial filter bag equipment for fine filtration and perhaps incorporating rare earth magnets to efficiently recover metal fines.

 

Particle Size and Contaminant Type: Hydraulic filters are designed to remove smaller particles and contaminants, such as dirt, debris, and metal shavings which damage hydraulic components like pumps, valves, and actuators. Industrial liquid filters focus on removing a broader particle range from 1 to 800 microns for sediments and impurities that can affect water quality or the performance of industrial processes.

 

Pressure Ratings: Hydraulic systems typically operate under high pressures, 145 to over 20,000 PSIG, requiring filters that can withstand these pressures without failure. Hydraulic filters are engineered to maintain their integrity and filtration efficiency under these high-pressure conditions. Industrial water and fluid filters may not need to withstand such high pressures and may be designed for lower pressure environments. (typically, 30 to 150 PSIG)

Fluid Compatibility: Hydraulic filters are designed specifically for hydraulic liquids, which often include additives and properties tailored to lubricate and protect hydraulic system components. These filters need to be compatible with various hydraulic liquids, including mineral oils, synthetic liquids, and water-based liquids. Industrial water and liquid filters may need to handle a broader range of fluids, including water, chemicals, oils, and solvents, necessitating different materials and construction methods.

 

Filtration Efficiency and Micron Ratings: Hydraulic filters typically have higher filtration efficiency and lower micron ratings (3 to 130 microns) compared to filters used for industrial water and liquids. This is because hydraulic systems require cleaner liquid to ensure the proper functioning and longevity of hydraulic components. Some hydraulic systems are so sensitive to contamination that monitoring equipment is installed to accurately determine the solid contamination, particle size distribution, water saturation, and temperature of hydraulic liquids in real-time.

 

 

 

While there are industrial filter bags, cartridges and screens for ≥ ½ micron retentions, they are often limited to differential pressures <30 PSI and are “oversized”, meaning they are inherently designed for higher flow rates then typical of a hydraulic system.

System Integration and Maintenance: Hydraulic filters are often integrated into hydraulic systems in a way that facilitates easy access for maintenance and replacement. They may be designed to withstand vibration, shock, and other conditions commonly encountered in heavy equipment and construction environments. Industrial water and liquid filters are often integrated into different types of systems, such as water treatment plants or manufacturing processes, where they are independently supported or supported by the pipeline and not specifically designed for vibration and shock associated with mobile equipment.

Industrial Applications for Hydraulic Filters
There are some industrial applications which benefit from fine filtration of particles under high pressure for which a hydraulic filter could be utilized, such as machining systems which use high pressure water for cutting or high-pressure coolant for lubrication, cooling and material ejection.
Water jet cutting systems use high-pressure water to cut through metal, stone and composite materials. The sapphire orifices used to apply the water are very fine and as such they are susceptible to wear and clogging from contaminates in the water supply. Filters designed for hydraulic systems are used for such applications due to their high-pressure ratings and fine filtration efficiency.

 

 

High pressure machine tool coolant applications refer to using an oil or water-based liquid for lubrication, cooling and ejection of cut material drilling, milling and lathing applications. The used coolant is filtered prior to reuse to extend the wear-life of pumps, rotary unions and tooling; it also has an added benefit of improving surface finish and supports faster operation of the machinery. Such systems often utilize industrial style bag filtration systems to retain large quantities of solids >50 microns on the suction side of the high-pressure pump system and a finer hydraulic filter to “polish” or remove particle <50 microns to protect downstream components. Depending upon the process, some machining applications rely solely on filtration on the high pressure (discharge) side of the pump system although most perform the filtration on the (lower pressure) inlet side of the pump system.

 

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