In need of new fuel or air filters? Our team at Sigma are here to help…

For other spare parts such as engines and hydraulic spares please contact us for more information.

Air Filter – 

Air Filters are an important part of your machines. Diesel engines have a reputation for being bulletproof. Today’s models are no less durable than before, but due to changes in exhaust emissions technology, they also require extremely clean fuel and air to function properly. Fail to provide either and you could be looking at expensive repair bills.
Hot and dusty conditions prevail on many earthmoving jobsites. This means close vigilance is needed when it comes to airborne dust on the jobsite, but also maintaining a best-practices regime when it comes to your equipment’s air filtration. If the water truck breaks down or fails to show, your machines may be facing a huge increase in the amount of dust they must filter out of the intake air.
Dust contains silica, which if it gets into your engine, acts like a lapping compound. It is highly abrasive and when stirred into your lube oil, blown turbochargers or a dusted engine are likely results.

Cleaning air filters unwiselyair filter
Years ago it was common practice for operators to remove their air filters and clean them. Some used compressed air, some used a wash system; and as a field expedient technique some would just bang the filter on the side of the machine to knock the dirt out. Today this is not recommended for two reasons. “First, you reduce the effective future life of that filter by 20 to 40 percent every time you clean it,” “Second, you increase the likelihood that you’re going to open up holes in the media and that’s going to give dust a direct line to the engine or the safety filter. It’s putting a major piece of equipment at risk.
Once your filter reaches maximum restriction, you may not notice a performance change at first, but most modern engines will eventually start to deteriorate. At the next stage, the engine could force you to limp the vehicle back home. The engine does this to protect itself from further damage.
Know how your air filters work and how to change them to avoid big repair bills!
Air filters are especially necessary with modern electronic engines, which have much higher injection pressures and less tolerance to impurities. Any CAT, Wirtgen, Komatsu, Volvo or Dynapac equipment with electronic injectors will require high performance fuel filters to help prevent damage to the injectors. Alternative manufacturers to the main engine brands are Donaldson, Baldwin and Mann Hummel filters. Please ask us for a competitive quote for the filters you want to buy.


Engine Filters – 

Engine oil filters are changed as standard on most machinery engines every 250-500 hours. Engine oil passes through the engine block to lubricate it and provide cooling, toEngine Filter maintain a constant operating temperature. It is then recirculated into the oil sump, which acts as the central store of oil for the engine.
Engine oil routinely picks up contaminants, such as metal worn from the engine block, dust and dirt. This then collects as sludge and increases the wear in the engine.
Effective engine oil filters collect this mixture of contaminants, and ensure a lower wear rate in the engine, and longer engine life.
All diesel engines have engine oil filters, so whether your equipment is fitted with a CAT, Cummins, Perkins, Deutz, Komatsu or Volvo engine, you will need to replace the oil filters regularly.

In addition, changing the oil is also a requirement to maintain a healthy lubrication system, and maximise the life of your engine. For service intervals recommended for your machine, please enquire for a Maintenance and Service Manual for your machine. Sigma regularly supply these for our machines, and we would be happy to quote you for these.
Sigma can support you with your engine oil filter requirements, so please ask us for a comparative quote for the filters you need. We can price for Donaldson filters, Parker filters, Mann & Hummel filters, Parker Hydraulics filters and Baldwin filters, please let us know your requirements.

Fuel Filter – 

Fuel filters need to be replaced regularly. If water is not removed from a machine’s fuel system, the water will rust and corrode engine parts. Fuel-water separators pull the water out of the system. Just because a product claims to remove 100 percent of the water, doesn’t quite tell the complete story. There are two types of water, one is referred to as “whole water,” and the other is “emulsified water”.Filters
Hard-to-remove emulsified water usually starts out as whole water. As a piece of equipment bumps, bounces and jars its way across a work site, the fuel sloshes around. The more it is stirred, the finer the water particles become. As a result, they are dispersed throughout the fuel and eventually end up in an emulsion, which is difficult to separate.
Free water is visible. If you put it in a jar, you can see the water sitting on top of the fuel. That’s very easy to remove because it’s basically already separated. Emulsified water, on the other hand, has been mixed so well into the fuel that it is composed of very, very small bubbles that are almost attached to the fuel.
Fuel-water separators should be considered from two standpoints: the efficiency of the unit to remove particles and its efficiency in removing both types of water. The job of a fuel-water separator system is to protect the engine.
Given the high injection pressures of Tier 2 and Tier 3 engines, fuel cleanliness is a must. To make sure that the fuel is exceptionally clean when it reaches the injection pump, providers are switching to two-stage, low-micron filtration. The purer the fuel, the more efficient and long-lasting the engine and the machine. You can either use filters which are branded the same as the engine, eg Cummins, Caterpillar, Volvo, Wirtgen. These are called ‘OE’ which stands for Original Equipment, and generally charge a price premium for the peace of mind. These filters will usually be branded as CAT filters, Wirtgen filters, or Dynapac filters. Often warranties on engines are dependent on OE or Genuine filters being used. An alternative to OE equipment is OEM filters, or ‘Original Equipment Manufacturer’.

This is where suppliers who supply filters for machinery manufacturers like CAT also sell filters under their own brand. These are generally cheaper, and still excellent quality filters. The third option is to buy Aftermarket filters, where filter suppliers who have no relationship with the machine manufacturer produce replica filters which they sell as compatible to a make and model of engine. With aftermarket, you must be careful that the quality is good enough – some manufacturers in China produce filters which leak or do not filter to the required performance, which is simply buying yourself trouble.


Hydraulic filters –

Hydraulic systems on mobile plant, such as excavators, wheel loaders, bulldozers, crushers and screens, work on exceptionally high pressures and require very fine tolerances in order to maintain optimum working performance. If contaminants enter the hydraulic system, they can cause accelerated wear on both the pump, which provides the pressure to the system, and the valve block and hydraulic rams.Hydraulic Filter

In order to remove the impurities and contaminates in the hydraulic system, high-pressure, in-line hydraulic oil filters are usually used. These filters remove impurities and extend the life of the hydraulic pump, valves and other components.

All mobile plant which uses hydraulic power, for instance Caterpillar equipment, Volvo machines, Bomag road making equipment and Terex Finlay/Pegson/Powerscreen crushers and screeners, will all require hydraulic oil filters. You need to change these regularly, with either OE filters or OEM filters. Please enquire for a competitive quote for your filter requirements.


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