Imagine you have a bunch of pebbles and you want to separate the small ones from the big ones. You can use your hands to pick them out one by one, but it will be very slow and tiring. Instead, you can use a sieve, which is a special kind of filter.
An impingement filter works in a similar way, but instead of pebbles, it is used to filter tiny particles from a fluid, such as air or water. It has a plate with lots of holes in it, and the fluid is forced through these holes. As the fluid flows through, any particles that are bigger than the holes get stuck on the surface of the plate, while the clean fluid passes through the other side.
Think of it like a water purifier that removes dirt and other things from the water to make it clean to drink. However, impingement filters are more commonly used in industrial processes such as oil refineries, where it is important to remove impurities from fluids that are used in the production of goods.