filters are made to remove particles from a fluid(air/gas/liquid). They are rated as to flow volume and particle size. There is a secondary rating of pressure drop as they gradually fill up with particles and slow the flow of fluid you reach a pressure drop across them. Often the volume allowed through also drops. At some point the filter must be changed and a new one used. Sometimes they employ backwashing to remove the trapped particles. Sometime they remove and wash the filter. Sometimes a new one and the old one tossed.
Each machine that has a filter will have a recommendation on filter change procedures and when to do it.
My question is misunderstood. Let me eleborate a bit more.
In case of depth type Hydraulic Oil filter element how manufacturer will arrive at the exact weight of the dirt holding capacity ?
When Element is brand new the weight is say X Kg. after the element gets chocked its weight is X+Y Kg. But this Y Component also includes the weight of the residual oil in the element. Weight of the residual Oil will have much more weight comapred to the weight of the dirt trapped. ( FYI Dirt holding capacity is indicated in grams.)
Even when one plots the pressure drop vis weight of the dirt, how for the first time when it is measured, it was clonclusively decided that the so much pressure drop is because of so much grams of dirt held by the element ?
In that case how the Y component will be devided into the weight of the oil as well as very accurately the weight of the micron size dirt.
An oil filter like that will usually be used until the pressure drop across it exceeds a certain value. At that time it will have a pressure drop sensor that will output a signal and the machine will light an indicator for the operator to take action. Some machines will have a second sensor, so if the operator ignores the first one and the pressure drop gets bigger and there is real risk of expensive damage to the machine it will shutdown or refuse the start after the next shutdown as a protective measure. This varies with the equipment. A $200,000 machine will be more likely to shut down to protect the machine than a $200 one
Most of the air filter are tested up to 2 international standards ASHREE & EU and by approved laboratories.
For example, in USA EAS and most laboratories uses the ASHREE standard to test the air filtration. The tests have certain procedure where they will blown dusts (ash particles) in the test panels and through the filters, while testing performance of the filters over time and checked for maximum pressure drop.
To go in detail of each the air filtration tests, please long in EAS or ITP test laboratories websites.
Dirt Holding Capacity
Re: Dirt Holding Capacity
