Service Clinic 2

“Role of filters and replacement frequencies”

The Filters are particularly important to have the correctly selected oil and fuel develop their intended performances. The filters installed on construction machines are somewhat equivalent to the liver, kidneys, and lungs of a human being. They remove foreign matter that would otherwise adversely affect the machines. While new cells naturally replace the old cells in the organs of a human being to maintain their functions, this unfortunately does not apply to the filters of the machines. The filters need proper maintenance such as cleaning and replacement. Here are some tips for maintaining the filters.


For engine oil filters

Q: Unlike the travel distance for passenger cars, construction machines have to change the engine oil filters every 500 hours of operation. This means that if a machine is operating on a busy site, engine oil would have to be changed once a month. Is it possible to extend the engine oil filter change frequency?

A: For proper lubrication, the engine oil deals with harsh conditions of high temperatures, high speed rotation, and high bearing pressure. There are a lot of causes that lead to engine oil contamination by foreign matter. For instance, the high temperature deteriorates the engine oil (by generating sludge and carbon matter), the sliding motion at high speed and high bearing pressure generates wear particles, and the fine dust and moisture in the atmosphere enters the engine oil. The amount of contaminants increases with time.

The engine oil filters remove these contaminants which, if otherwise re-circulated into the engine, could cause machine failure. Because of the finite capacity of a filter, when a filter has captured contaminants to its capacity, it may let excess contaminants pass through the filter paper. Note also that the high temperature and high pressure oil makes the filter paper that is generally available deteriorate with time.

That is why we specify that the engine oil filters be replaced at the same time as changing the engine oil.


Fuel filter

Q: We refuel the machine with clean fuel from a gas station. Do we still need to replace the fuel filters?

A: There are a lot of opportunities for impurities such as dust to enter the fuel tank. Some instances are as follows.

1. Dust in the air enters the fuel tank through the filler port.

2. When fuel is consumed, the air volume in the fuel tank increases. Changes in temperature cause the moisture in this air volume to precipitate, eventually entering the fuel.

3. The moisture entering the fuel oil as described in 2 (above) causes the inner surfaces of the fuel tank to corrode, which eventually becomes foreign matter.

4. Air coming in and out brings dust into the fuel tank.

Recent engines complying with the mandatory exhaust emission regulations are extremely sensitive to moisture and foreign matter because they use the fuel to lubricate the ultra-high pressure fuel injection systems. This makes changing the fuel filter just as important as changing engine oil filters. The filtering paper of the fuel filter also uses filter paper in general, which deteriorates with time. Thus, use clean fuel and replace the fuel filters according to the specified frequency.


For air filters (air cleaners)

Q: How do you replace the filter element in general? Do you still need to replace the element if the machine operates on a site with clean air?

A: Let’s look at the most common type of dry-type paper filter element. When the element gets clogged in an environment with ordinary dust, the suction resistance of air into the engine increases and prompts the clog indicator to generate a warning. If a warning is issued, remove the element and use low pressure compressed air to blow off the dust from inside to outside the element to clean it. Do not use very high pressure compressed air or impact the element. The filter paper in the element will break or expand its mesh to let unwelcome dust pass through the filter. Even if the machine operates in a seemingly clean environment, fine dust that is not visible to the naked eye exists. You need to maintain the filter element because even such fine dust entering the engine could cause the engine to fail. In this case, since the element may not be excessively clogged, the indicator may take longer before generating a warning. However, the fluctuation of engine suction pressure and deterioration over time makes the filter paper mesh coarse and easy to break. Be sure to replace the filter element once every year.

Filters are important parts corresponding to the liver, kidneys, and lungs of a human being. Let them stay healthy and the machine will work well for you.

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