Filter holder, filter element and filter arrangement

A filter arrangement, comprising:

• a filer element having an oval-shaped cross section, the filter element comprising:
• an oval-shaped filter medium surrounding a center axis (MA) of the filter element;
• a first end plate arranged on a first axial end of the oval-shaped filter medium;
• a second end plate arranged on a second axial end of the oval-shaped filter medium;
• wherein the filter medium is a folded filter medium, folded in a zig-zag pattern;
• wherein a radially outer surface of the oval-shaped filter medium (4) forms an oval-shaped radially outer face;
• wherein the filter element has an incident-flow guard that covers the oval-shaped radially outer face at least partially;
• a filter holder having a receiving section having an oval shaped wall surrounding the center axis (MA), the oval shaped wall defining and surrounding an oval-shaped interior space of the receiving section;
• wherein the filter element is received into the oval-shaped interior space of the receiving section;
• wherein the oval-shaped radially outer face of the oval-shaped filter medium has a largest diameter (b) extending through center axis (MA) to a smallest radius curved section of the oval-shaped radially outer face;
• wherein the oval-shaped radially outer face of the oval-shaped filter medium has a smallest diameter (h) extending through center axis (MA) and perpendicular to the largest diameter (b);
• wherein a constant radial spacing distance (a) is provided between the oval-shaped radially outer face of the oval-shaped filter medium and the oval shaped wall of the receiving section around the filter element, forming an oval flow space having a constant radial width (a);
• a tubular fluid inlet formed on the filter holder having an inlet flow channel oriented perpendicular to the largest diameter (b), the tubular fluid inlet positioned to discharge a fluid directly into a first end of the oval flow space immediately at the smallest radius curved section of the oval-shaped radially outer face, such that the fluid is thereby accelerated to flow helically and tangentially around the oval-shaped radially outer face of the filter element, thereby, separating particles contained in the fluid onto an interior side of the oval-shaped wall of the receiving section with the aid of centrifugal force;
• whereby for optimized particle pre-separation, the largest diameter (b) relative to the smallest diameter (h) is between 3:1 and 1.5:1;
• wherein the filter element is covered at least partially by an incident-flow guard arranged between the oval-shaped radially outer face of the filter element and the oval flow space, positioned adjacent to where the tubular fluid inlet discharges the fluid into the oval flow space.