Fixed Auxiliary Filtration Systems

Fixed Auxiliary Filtration Systems purpose-built to protect your most critical assets—24/7. Guardian’s fixed filtration systems deliver continuous kidney-loop protection for industrial power units, gearboxes, heat exchangers, diesel fuel tanks, and more.

Unlike factory-installed pressure and return filters—often low-capacity, expensive, and only active when the equipment is running—our permanently installed systems operate independently via offline pumps, filtering contaminants even when your equipment is offline.

Each system is custom-engineered for seamless integration and equipped with high-capacity depth media filters capable of capturing microscopic particles and free water, with holding capacities up to 8 lbs, depending on the application. This allows for dramatically extended filter life, fewer changeouts, and lower overall maintenance costs.

Contaminants as small as 1 micron—70 times smaller than a human hair—are responsible for the majority of system wear, varnish formation, and premature failures. Our offline filtration systems quietly eliminate those risks, enabling longer oil drain intervals, improved thermal stability, and consistently clean fluid—all without interfering with equipment performance or violating OEM warranties. From the hydraulic reservoir to the gearcase, nothing runs cleaner. Nothing lasts longer.

Only Guardian delivers industrial-grade, permanent kidney-loop filtration—engineered for maximum uptime and long-term reliability.

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The Guardian Systems

Reliability Through Continuous Fluid Conditioning

Hydraulic Power Units (HPUs) are the central nervous system of industrial motion—responsible for controlling mission-critical operations in manufacturing, material handling, forestry, and process plants. Yet despite their rugged design, HPUs are highly vulnerable to the silent killer of hydraulic systems: fluid contamination. Studies from the National Fluid Power Association (NFPA) and industry leaders confirm that up to 82% of all hydraulic failures can be traced back to contamination—whether from particulate, moisture, oxidation byproducts, or varnish precursors.

As modern HPUs operate at higher pressures, tighter tolerances, and elevated temperatures, the impact of even microscopic contaminants is magnified. Elevated ISO cleanliness codes are directly linked to erratic valve behavior, actuator stalling, premature pump wear, and the breakdown of elastomeric seals. Compounding the issue, scheduled preventive maintenance (PM) intervals often fail to account for rapidly accelerating fluid degradation caused by thermal stress, leading to PM fade and unexpected downtime.

Traditional onboard return-line or pressure-line filters are not equipped to capture ultra-fine particles, nor do they remove water or oxidation residues effectively. These systems protect against catastrophic debris, but allow fine contaminants to circulate continuously—undermining system performance and shortening equipment life.

The Guardian Fixed Auxiliary Filtration System is purpose-built to address these shortcomings. Installed as a permanent, dedicated offline (kidney-loop) filtration circuit, it operates independently of the main hydraulic flow—ensuring continuous fluid conditioning even when the system is idle. Using high-capacity, depth-type filter elements, Guardian systems remove sub-micron particles, dissolved varnish precursors, and free or emulsified water from the fluid reservoir—delivering dramatic reductions in ISO codes and ensuring the hydraulic fluid meets or exceeds OEM cleanliness standards.

Each system is designed for 24/7 operation with robust pumps and motors rated for industrial duty cycles. Filter elements hold between 2–8 lbs of particulate, depending on system size, and deliver long service life between changeouts. Some models are equipped with moisture-absorbing media, while others include varnish-removal chemistries to combat oxidation at its root.

Benefits of a Fixed Guardian Auxiliary System include:

  • Extended Component Life – Clean fluid reduces wear on pumps, valves, actuators, and seals.
  • Lower Maintenance Costs – Reduce unplanned downtime and extend PM intervals.
  • Improved Thermal Performance – Reduced varnish allows for better heat transfer and more stable fluid temperatures.
  • Extended Fluid Life – Many users achieve 2x to 4x longer drain intervals.
  • Environmentally Friendly – Fewer fluid changes mean less waste oil and lower disposal costs.
  • Warranty Safe – Guardian systems do not alter OEM fluid dynamics and are fully compliant with warranty terms.

Whether retrofitting an older hydraulic system or designing a new HPU from the ground up, Guardian Fixed Auxiliary Filtration Systems deliver proven reliability gains and measurable ROI. With plug-and-play electrical packages, multiple filter housing sizes, and optional remote diagnostics, they can be seamlessly integrated into virtually any industrial hydraulic application.

The result? Stable ISO codes, reduced lifecycle costs, and optimized HPU performance—regardless of load, temperature, or duty cycle.

From gearboxes and turbines to heat exchangers, diesel generators, and rotating equipment—industrial machines depend on clean, stable lubricants to deliver consistent performance and long-term reliability. Yet across all sectors, lubrication-related failures remain one of the leading causes of unplanned downtime, lost production, and premature component wear.

According to industry data from Noria and Machinery Lubrication, up to 70% of mechanical failures are caused by oil contamination—including solid particulates, water, oxidation byproducts, and sludge. These contaminants degrade lubricants over time, forming deposits that reduce heat transfer, cause varnish accumulation, plug orifices, increase operating temperatures, and erode mechanical surfaces. Unfortunately, standard sump filters or strainers provide limited protection, capturing only large debris while allowing damaging micro-contaminants to circulate unchecked.

The Guardian Fixed Auxiliary Filtration System is engineered to combat these risks across a wide range of industrial oil systems. Installed as a dedicated kidney-loop filtration circuit, the system continuously processes lubricant from the reservoir—independent of the equipment’s duty cycle. This means the system is filtering and conditioning fluid 24/7, whether the asset is running, cycling, or idle.

By incorporating multi-stage depth filtration, water-absorbing elements, and varnish-control technologies, Guardian systems remove ultra-fine particulate, emulsified water, and oxidative degradation products that traditional filters simply miss. With filter element capacities ranging from 2–8 lbs of contaminant, depending on system size, Guardian units are built for long service life in harsh environments.

Ideal for:

  • Gearboxes & Speed Reducers (wind turbines, conveyors, mixers)
  • Heat Exchanger Circuits & Cooling Loops
  • Diesel & Gas Generators
  • Steam & Gas Turbines
  • Centrifuges, Pumps, and Motors
  • Hydraulic Reservoirs or Compressor Lubrication Circuits

System Benefits:

  • Extend Gear & Bearing Life – Clean oil drastically reduces abrasive and fatigue wear.
  • Prevent Varnish Formation – Reduce thermal degradation and oxidative residue buildup.
  • Lower Fluid Temperatures – Clean oil improves thermal transfer and cooling efficiency.
  • Maximize Equipment Uptime – Reduce filter plugging, stuck valves, and thermal alarms.
  • Increase Oil Drain Intervals – Many applications see 2x–5x extension in service life.
  • Protect New Equipment – Ensure startup cleanliness and maintain OEM warranty standards.

Each Guardian unit is constructed with industrial-grade motors and positive displacement pumps, ensuring reliable performance in high-viscosity or high-contaminant environments. Optional upgrades include real-time ISO particle monitoring, moisture sensors, and remote alert integration—delivering condition-based insights for smarter maintenance decisions.

Whether retrofitting aging gearboxes or designing filtration into new assets, Guardian Fixed Auxiliary Filtration Systems deliver measurable reductions in contamination, operating cost, and risk.

Clean Fuel Starts at the Source

Every fuel-related issue begins in the bulk tank—the origin point of most contamination in modern diesel systems. Whether it’s microbial growth from standing water, solids from tank corrosion, or particulate picked up during fuel transport, your fuel is already compromised before it ever reaches a filter, pump, or injector. Today’s diesel engines demand cleaner fuel than ever before.

With high-pressure common-rail injection systems operating at over 30,000 PSI and OEM cleanliness requirements as strict as ISO 12/9/6, even trace contaminants can lead to:

  • Injector scoring and premature failure
  • Plugged fuel filters
  • Poor fuel atomization and combustion efficiency
  • Aftertreatment failures (DPF, SCR, EGR)
  • Derating events and lost productivity

The Guardian High-Efficiency Diesel System

Guardian’s fixed auxiliary diesel filtration systems are purpose-built to continuously condition stored diesel fuel. Installed in a dedicated kidney-loop configuration on bulk or day tanks, the system recirculates and polishes fuel 24/7—removing particulate, water, microbial byproducts, and oxidation residues. Unlike standard in-line filters that only protect components during fuel transfer, Guardian’s system ensures the fuel in your tank always remains clean—providing total fluid assurance.

Key Benefits:

  • Protects OEM filters, injectors, and pumps from premature wear and fouling
  • Reduces water content and microbial activity that lead to sludge and corrosion
  • Improves combustion efficiency and fuel economy
  • Prevents costly aftertreatment failures and excessive regeneration cycles

Why It Matters:

  • 90% of diesel engine failures are caused by poor fuel quality
  • Microbial growth can begin with just 0.5% water content in stored fuel
  • Plugged filters are a top 5 cause of generator failure during critical load events

Fuel is not just a consumable—it’s a reliability factor. With a Guardian Diesel System in place, your bulk storage becomes your first line of defense—not your greatest vulnerability.

Case study

A southern Oregon sawmill was experiencing two servo valve failures per month. Each failure represented a $10,000 repair, plus additional costs from lost revenue due to downtime, costing the sawmill upwards of $240,000 annually.​

Guardian Reliability Services (GRS) suggested system modifications and cleanliness monitoring. Under our recommendation, they implemented proactive filtration systems tailored to their hydraulic power units. GRS also provided regular analysis of hydraulic cleanliness levels​, and filtration services were dispatched as needed based on monitored data​.

A $40,000 investment in GRS preventative services eliminated valve failures, resulting in a proven ROI of over $200,000 annually in direct savings.

The failure rate was reduced from two failures per month to 0 failures in 12 months, providing them with operational assurance that their equipment would perform reliably, with minimal downtime.​​

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