Dec 07 2023
Let's explore the proper usage of a filter element which is designed to filter a range of media, such as air, liquids, and oil gas. Initially, it's important to differentiate between two essential components of the filter element: the inlet side for the media (upstream side) and the outlet side for the media (downstream side).
To ensure optimal performance, filter papers are typically designed with a front and back side, with one side featuring a special marking line. This not only helps align the filter element's inlet and outlet directions but also provides the best dust-holding capacity and filtration efficiency. Let's delve into the design principles of the filter paper: the side near the inlet has larger pore sizes, primarily designed to block larger particles, while the side near the outlet (with the marking line) has smaller pore sizes, intended for blocking finer particles.
Taking the FA-1072 as an example, based on the filtration direction, we refer to this type of filter element as external inlet and internal outlet. Please note that the filtration direction may vary for different filter elements; for instance, hydraulic return oil filter elements are often designed oppositely, with internal inlet and external outlet. Nevertheless, it is crucial that the pore sizes on the upstream side of the filter paper are always greater than or equal to those on the downstream side, ensuring proper usage.
Determining the Inlet and Outlet Direction of the Filter Element
Understanding the inlet and outlet direction of a filter element is crucial when using it. Here are several methods to help you easily determine the flow direction of the filter element:
1. Inner/Outer tube Evaluation:
The inner and outer tube (metal or plastic) serves both as a support structure for the filter paper and an indicator of the flow direction.
- If only the inner tube is present without the outer tube, the typical flow direction is from outside in.
- If only the outer mesh is present without the inner tube, the typical flow direction is from inside out.
- If both inner and outer pipe are present or absent, determining the flow direction solely based on this factor may not be conclusive.
2. Line Markings Evaluation:
Check for special markings on the filter paper, which serve as an indication of the flow direction.
- The side where the marking line is located represents the downstream of the filter element.
3. Metal Shell Spin On Filter Evaluation:
For metal shell spin on filter, unfiltered dirty oil usually enters through the outer ring holes of the threaded plate.
And exits through the central threaded hole. The flow direction of the filter element inside the metal shell is typically from outside in.
We hope this tutorial provides you with a better understanding of the structure and usage of filter elements.
