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We Offer Donaldson Engine and Hydraulic Aftermarket Filters to replace Baldwin Filters in the UK.

The Filter Guys

We Offer Donaldson Engine and Hydraulic Aftermarket Filters to replace Baldwin Filters in the UK.

At Sterling Filtration Ltd we offer over 3,000 Donaldson equivalent filters to replace your Baldwin filters. They cover a huge range of engine filters (main air, safety air, lubricating oil, fuel, fuel water separators) and hydraulic system filters.

Please check out our range by clicking on the Donaldson Brand Icon below.

If you have any requirements for Baldwin equivalent filters please give us a call today on 01902 491118. We are here to service your filter needs!

Pre-line Fuel Filtration Housing.

The Filter Guys

Today, diesel vehicles are fitted with the latest high performance fuel injection systems. As a result, fuel filtration must meet far more demanding requirements. Pre-Line is a universal and practical pre-filter system, based on the spin-on filter concept, which provides an ideal, cost-saving retrofit solution.

Features and advantages

  • Use with diesel fuel DIN ISO 590 (5% FAME), DIN 51 628 (7% FAME)
  • Up to 600 l/h volume flow rate
  • Use of multigrade high performance media
  • 93% water separation
  • Modular system with excellent flexibility
  • Easy to service
  • Integrated, effective and easy to handle hand pump with 45 degree position to drain off water and for priming during service
  • Integrated water collector
  • Parallel operation possible with a number of systems

These filter housings from Mann Filter are available from Sterling Filtration Ltd.


How Filter Media Functions In a Filtration System

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How Filter Media Functions. The job of the media is to capture particles and allow the fluid to flow through. For fluid to pass through, the media must have holes or channels to direct the fluid flow and allow it to pass. That’s why filter media is a porous mat of fibers that alters the fluid flow stream by causing fluid to twist, turn and accelerate during passage.

The fluid changes direction as it comes into contact with the media fibers, as illustrated above. As the fluid flows through the media, it changes direction continuously as it works its way through the maze of media fibers. As it works its way through the depths of the layers of fibers, the fluid becomes cleaner and cleaner. Generally, the thicker the media, the greater the dirt-holding capacity it has.

Looking at a cross-section view of the fibers:

we can see how the flow stream is accelerated as it flows into the spaces between the fibers.

This is applies to all liquid filters, be they oil, fuel, water of water glycol. For more information on filtration products and replacement elements please contact us for a chat. We’re here to help.

How Filter Media Collects Particles

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How Filter Media Collects Particles. There are four basic ways media captures particles.

The first, called inertia, works on large, heavy particles suspended in the flow stream. These particles are heavier than the fluid surrounding them. As the fluid changes direction to enter the fiber space, the particle continues in a straight line and collides with the media fibers where it is trapped and held.

The second way media can capture particles is by diffusion. Diffusion works on the smallest particles. Small particles are not held in place by the viscous fluid and diffuse within the flow stream. As the particles traverse the flow stream, they collide with the fiber and are collected.

The third method of particle entrapment is call interception. Direct interception works on particles in the mid-range size that are not quite large enough to have inertia and not small enough to diffuse within the flow stream. These mid-sized particles follow the flow stream as it bends through the fiber spaces. Particles are intercepted or captured when they touch a fiber.

The fourth method of capture is called sieving and is the most common mechanism in hydraulic filtration. As shown at right, this is when the particle is too large to fit between the fiber spaces.

Where Contamination Comes From.

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Where Contamination Comes From.

New Hydraulic Fluid

Adding new fluid can be a source; even though it’s fresh from the drum, new hydraulic fluid isn’t clean. (It may look clean, but, remember, the human eye can only see a particle the size of about 40 μm.) Oil out of shipping containers is usually contaminated to a level above what is acceptable for most hydraulic systems: typically, new fluid has a cleanliness level about the same as ISO Code 23/21/19, and water content is typically 200 to 300 ppm. Never assume your oil is clean until it has been filtered. One very effective way of ensuring thorough fluid conditioning is with a dedicated off-line circulation loop, or “kidney” loop filtration.


Built-in contamination, also called primary contamination, is caused during the manufacture, assembly and testing of hydraulic components. Metal filings, small burrs, pieces of Teflon tape, sand and other contaminants are routinely found in initial clean up filtration of newly manufactured systems.


Ingressed or external contamination comes from the environment surrounding the system. Dirt can enter the hydraulic fluid supply through leaking seals, reservoir breather caps, and worn cylinder rod seals. Ingressed moisture, particularly, can cause long-term problems. As a hot system cools at night, cool moisture-laden air can be drawn into the reservoir; as the air condenses, water is released into the reservoir. Water in excess of 0.5% by volume in a hydrocarbon-based fluid accelerates the formation of acids, sludge and oxidation that can attack internal components, cause rust, and adversely affect lubrication properties. The severity of ingression and type of contaminant are dictated by the applications and environment.


Maintenance procedures can introduce contamination into the system. Opening the system allows airborne particles to enter. Leaving the system open during operation provides continuous ambient particle ingression. Keep your system closed as much as possible.


The major source of contamination are the pump and actuators, the hydraulic cylinder, or the hydraulic motor. Wear-generated contaminants are a hazard during normal hydraulic system operation. The circuit actually generates additional particles as the fluid comes into contact with the precision machined surfaces of valves, motors and pumps. Contaminant levels can keep doubling with every new particle generated. The result can be catastrophic if these contaminants are not properly filtered out of the system.

Rubber & Elastomers

Due to temperature, time, and high-velocity fluid streams, rubber compounds and elastomers degrade—thus releasing particulates into the fluid. This may be from hoses, accumulator bladders, seals, or other elastomer products.

High Water Based Fluids

The water in HWBF tends to support biological growth and generate organic contamination and microbes.

Replacement of Failed Components

Failure to thoroughly clean fluid conductor lines after replacing a failed hydraulic pump will cause premature catastrophic failure. Donaldson recommends frequent oil sampling to ensure proper contamination control. Sample test points should be close to hydraulic pumps and at other key locations that provide safe, reliable access to the fluid while under full system pressure.

Spark Arrestors

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The general rule with spark arrestors is if it will fit on the exhaust pipe of an engine, it will also have an acceptable back pressure for that engine. In some cases, a larger size spark arrestor will be required to stay within backpressure limits, and in those cases adapters will have to be used.


The spark arrestor should be inspected and cleaned out every 1,000 operating hours or three times per season. Visually inspect for holes, cracks and metal corrosion. Check the mounting clamp to make sure the spark arrestor is securely mounted. Replace the spark arrestor if your inspection reveals any of the above unsafe conditions.


  • US Forest Service approved
  • Reduced fire hazard – 95% or greater efficiency on incendiary sparks
  • Centrifugal force separates solids from exhaust gas
  • Aluminized steel with stainless steel critical parts
  • Can be installed vertically or horizontally (If possible, the clean out should face away from all fuel tanks, the vehicle operator’s position and the air cleaner inlet.)

All of the above spark arrestors are available from Sterling Filtration Ltd. Give us a call on 01902 491118 for a competitive quote.

Fuel Filter Primary and Secondary for Detroit Diesel Engines – Special Offer.

The Filter Guys

We currently have stock of the primary and secondary fuel filter for Detroit Diesel series of engines.

Parts P550958 (equivalent to FF5036) and P550959 (equivalent to FF5037) are currently available from us at the amazing price of £20.00 net each +VAT for the pair. We are currently holding stock of 33 pairs of these filters and are offering them to you at this amazing one time offer, while stocks last. They are available as individual units too at only £10.50 net each +VAT.

Please call Sterling Filtration Ltd on 01902 491118 to find out more or to place an order.

Changes to Gas Oil Used in Off-Road Equipment.

The Filter Guys

From the 1st of January 2011 all gas oil (red diesel) for use in off road machinery and boats will contain no more than 10mgs of sulphur per kilo of fuel (current level is 1000mgs/kg). The changes are to reduce burned sulphur from entering the atmosphere. The Department of Transport are advising all gas oil users of the following precautions when storing and using red diesel for off road and recreational boat use:

Increased care when storing: The oxidation stability of this fuel will be poorer than that of current gas oil. This can cause solids to form in the gas oil. This will cause increased contamination that will require filtering from the gas oil. Suitable and regular filtration of the fuel will help prevent wear and tear on transfer pumps or off road engines.

Water removal: Water in fuel encourages bacterial growth which can block fuel systems and damage engines. Increased use of bio fuel as an additive to modern gas oils means that there is an increased risk of bacterial growth where water is present. Ensuring that suitable water separators are fitted can help reduce bacterial growth and reduce down time from breakdowns.

Solvent characteristic of the low sulphur fuel: The new sulphur free gas oil has a more solvent characteristic than current gas oil and will potentially remove any deposits within the storage tank. It is advised that fuel tanks are cleaned and equipment filters be replaced after the initial 2-3 tank fills of sulphur free gas oil and then be maintained and serviced regularly. If ever in doubt, change your fuel tank filters.

The cost of regular filter servicing is much lower and cost effective than the cost of even one single pump or engine fuel system replacement.

Further information and advice can be found on the Department for Transport web site by following the following link:


British Antarctic Survey.

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Sterling Filtration Ltd has supplied air filters to the British Antarctic Survey. The British Antarctic Survey (BAS) is the UK’s national Antarctic operation and has an active role in Antarctic Affairs. BAS is part of the Natural Environment Research Council (NERC) and has over 400 staff. It operates five research stations, two ships and five aircraft in and around Antarctic. It’s involved in joint research projects with over 40 UK universities.

National Oceanography Centre.

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Sterling Filtration Ltd has been a supplier of various filters to The National Oceanography (NOCS) in Southampton. The National Oceanography Centre, (formerly Southampton Oceanography Centre), is a collaborative Centre owned by the Natural Environment Research Council (NERC) and the University of Southampton. NOCS is based at a purpose-built waterside campus in Southampton, and is home to some 520 research scientists, lecturing support and seagoing staff as well over 700 undergraduate and postgraduate students.

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