In the process of using the filter element, it can be considered that it is a flow passage section which gradually decreases with the interception of solid particulate pollutants.
The flow through the filter element is the flow in the pipeline where the filter is installed. The filter element will not change the flow. With the interception of solid particulate pollutants, the area of the flow cross section (hereinafter referred to as the flow area) of the filter core becomes smaller, and the pressure loss through the filter core increases gradually. When a certain value is reached, the filter equipped with a transmitter sends an alarm through the transmitter to inform the user to replace the filter core in time.
If the filter element is not replaced in time, the flow area of the filter element will further decrease with the interception of pollutants, and the pressure loss will further increase. In addition to the alarm of the transmitter, the bypass valve of the filter equipped with the bypass valve will also open, and some oil will flow directly from the bypass valve without filtering the filter core. Even the pollutants intercepted by the filter element will be directly carried to the downstream of the filter element by the bypass valve, which will make the previous filter interception invalid and cause great damage to the components of the hydraulic system.
But even if part of the oil is flowing away from the bypass valve, the oil still flows through the filter core. The filter core continues to intercept pollutants. The flow area further decreases, the pressure loss further increases, and the bypass valve enlarges the opening area. In this process, the flow area of the filter core keeps decreasing and the pressure loss keeps increasing. When it reaches a certain value (this value must have exceeded the normal pressure value of the filter core or filter), when it exceeds the pressure bearing capacity of the filter core or even the filter, it will cause the damage of the filter core and the filter shell.
The main function of the bypass valve is to provide short-term oil bypass when the filter element can not be changed at any time (or at the premise of sacrificing the filter effect). Therefore, when the filter element is blocked, the filter element must be replaced in time, and the filter element should not be replaced normally because of the protection of the bypass valve.
In order to provide the most reliable protection for hydraulic system components, we recommend that filters should not be equipped with bypass valves as far as possible.