Hydraulic filter is a component within the hydraulic system, consist of porous cartridges, which can capture contaminants and avoid damages to the downstream equipment. In order to prevent its clogging, regular replacement and maintenance is very necessary, in this article I will introduce you the time when you should change hydraulic filters.
1. Why It Need Change and Maintain in Time
Hydraulic filters protect your system by trapping contaminants and preventing them from continuing to circulate, however, over a long period of time, contaminants that build up in the filter can form clogs, which can cause the filter to become over-pressurized or even overloaded resulting in a loss of filtration. Therefore, regular inspection and replacement is very important.
Here are two situation may happen when your hydraulic filters have problems. If you have a bypass valve in place, contaminated fluid is likely to participate in the ensuing cycle through it and cause damage to the surfaces of downstream components. While without a bypass valve, the continued increasing pressure from clogging of these fluids can cause the filter to rupture and even contaminate and even damage the entire system.
2. What’s the Condition in Which the Hydraulic Filters Need Change
2.1 Duration of Use
2.1.1 Regular Replacement According To The Advice
It is advised for you to change the Hydraulic Filters in proper time, as early and too late replacement can both cause losses.In general, You will always be advised to change it per 500 h or 3 months by the manufacturing company after buying the hydraulic filters, which are the basic method to maintain the equipment.
2.1.2 Situations May Decrease the Service Life
However, those advised changing cycle can not decide the changing time entirely. Here are a few scenarios that may require you to shorter replacement intervals, and you’ll need to check the status of your equipment on a regular basis and be more flexible in deciding the time to change hydraulic filters.
- System Work Intensity
The intensity of the system’s operation is one of the factors that may affect the service life, too. If the hydraulic system is operated under high load conditions like longer working hours or high readings on pressure gauges, this will require you to shorter the replacement intervals to prevent system from breakdown.
- Dusty and Humid Environments
The environment of work is also a factor you need to think. When your equipment is in a dusty and humid environment, the pollution in the air is easy to enter the system and may reduce replacement cycles by 30-50%.
- The Effect of the Season
The season may affect the cycle to replace, too. Cold winter temperatures may cause an increase in oil viscosity and higher differential pressure in the filter element. Therefore it is a good idea for you to check or change your hydraulic filters before winter. While in summer, the high temperature may accelerate the aging of the filter material, also shortening the life cycle.
2.2 Other Trouble Signals
However, you can’t always decide when to replace a filter just based on the specified replacement intervals. It is also important to know the abnormal conditions that require filter replacement. The following are signs that you should be aware of and change your hydraulic filter.
2.2.1 The Sudden Increase of the Temperature in Operating
If you find a sudden increase during the operating process, this will be not good and always means that the equipment is working out of order. Then you need to keep a eye on it and stop the machine to identify the cause of the problem.
Typically, the temperature rises because the filter is clogged, making the oil pass through narrow gaps, during which friction produces a large amount of heat , and the ability to dissipate heat is reduced due to less efficient circulation of the oil.
2.2.2 Decrease in system performance
The decreased performance of your machine is an obvious signal for you to know the hydraulic filters are in trouble. And this may appear to be The action of the hydraulic cylinders or motors is slow and the time to respond to commands is prolonged.
This occurs when the filter becomes clogged, which results in insufficient fluid flow and reduced system pressure to push the load fast enough and also cause a delay in system response time.
2.2.3 Excessive Noise and Vibration
If you notice vibrations and loud noises from your hydraulic pump, this is most likely due to a clogged suction line. This situation usually occurs because the filter has been used for a long time without cleaning and replacing, or there is dirt into the filter, resulting in poor oil suction.
This situation makes the air that was originally dissolved in the oil separate out, and will make the equipment work with great vibration, even prematurely damage the parts of the equipment. Whatever the reason, you need to stop the work of the equipment and immediately carry out the replacement of the filter.
2.2.4 Differential Pressure Alarm
You can use the indicator to monitor the pressure and determine whether the filter should be replaced based on the displayed value and the alarm. Normally, when the filter element is clogged, the pressure difference between its inlet and outlet will exceed the set value, the indicator will show red or sound an alarm, and you need to change the filter immediately.
In a particular system, the optimum time to replace the return filter element may be 2 bar above or below the blockage indicator switching pressure. Continuous monitoring of the pressure on the filter element will also provide an early warning of component failure and element rupture.
If the pressure drop (Delta P) across the pressure cartridge suddenly rises from 1 bar to 3 bar (all else being equal), this may indicate impending failure of an upstream component. Similarly, a sudden drop in pressure drop (Delta P) may indicate a ruptured cartridge. You can also transmit such status information to a computer program by installing a sensor, which is also more intuitive.
2.2.5 Oil Contamination Test Results
In the above article we mentioned that fluids usually need to be changed once a year, but that doesn’t mean that you don’t have to check the level of contamination particles in the fluid on a regular basis.
During the check process, if you find that the fluid contamination level has exceeded the limit, you will need to replace the filter because under such conditions the fluid has been contaminated and means that the condition of the filter is no longer good.
3. If They can be Cleaned and Reused
Although some parts of the filter can be cleaned and reused, I would recommend that you replace rather than reuse them. For example, even when cleaned very thoroughly, contaminants may also be carried into the filter unit and damage the filter or hydraulic system.
Thus, I think it is not a good idea to reuse the hydraulic filters and you are better to replace the entire unit if necessary.
With the above steps introduced, along with and the careful, consistent observation you carry next, I believe you will know when to change the hydraulic filters better, hope this article will be helpful to you.
