Fluid Filtration Apparatus and Method

A filter apparatus, having a filter inlet and a filter outlet, the filter apparatus comprising:

• a housing;
• a bypass filter including a bypass filter media having a bypass filter efficiency for removing particles of a given size;
• a full flow filter including a full flow filter media having a full flow filter efficiency for removing particles of the given size, with the full flow efficiency being higher than the bypass efficiency;
• and
• a flow balancing element;
• the bypass filter and full flow filter each having a respective fluid inlet connected to one another in a parallel circuit relationship by the housing;
• the bypass filter and full flow filters each also having a respective fluid outlet connected to the flow balancing element;
• the flow balancing element having a full flow inlet, a bypass inlet and an outlet interconnected within the flow balancing element in fluid communication with one another, with the full flow inlet of the flow balancing element being connected in fluid communication in a series fluid circuit relationship with the outlet of the full flow filter, the bypass inlet of the flow balancing element being connected in fluid communication in a series fluid circuit relationship with the outlet of the bypass filter for guiding the portion of the fluid passing through the full flow filter from said full flow inlet of the flow balancing element to said outlet of the flow balancing element and combining it with the portion of flow passing through the bypass filter and restricted by the bypass inlet of the flow balancing element, and the outlet of the flow balancing element being connected in fluid communication in a series flow relationship with the filter outlet of the filter apparatus and
• at the operating temperature, the portion of fluid filtered by the full flow filter that is exiting the flow balancing element will be larger than the portion of the fluid filtered by the bypass filter that is exiting the flow balancing element, and at a predetermined temperature below the operating temperature the portion of fluid filtered by the bypass filter that is exiting the flow balancing element will be larger than the portion of fluid filtered by the full flow filter that is exiting the flow balancing element.

A method for filtering a fluid with a spin on oil filter having a housing, and defining an inlet and an outlet of the filter apparatus, the method comprising:

• providing a bypass filter, having a bypass filter inlet and a bypass filter outlet, and including a bypass filter media disposed between the bypass filter inlet and outlet, the bypass filter media having a bypass filter efficiency for removing a particle of a given size;
• providing a full flow filter, having a full flow filter inlet and a full flow filter outlet, and including a full flow filter media disposed between the full flow filter inlet and outlet, the full flow filter media having a full flow filter efficiency for removing a particle of a given size, with the full flow filter efficiency being higher than the bypass filter efficiency;
• providing a flow balancing element, the flow balancing element being disposed within the bypass filter and having a generally tubular sidewall defining an interior of the flow balancing element, a full flow inlet disposed at a first end of the flow balancing element, a bypass inlet comprising an unimpeded orifice disposed in the sidewall of the flow balancing element that is sized to balance the amount of fluid received into the interior of the flow balancing element from the bypass filter, and an outlet disposed at a second end of the flow balancing element, the full flow inlet of the flow balancing element, the bypass inlet of the flow balancing element, and the outlet of the flow balancing element being interconnected in fluid communication with one another inside the flow balancing element, with the bypass inlet of the flow balancing element and the full flow inlet of the flow balancing element disposed in a parallel fluid circuit relationship to one another and the outlet of the flow balancing element disposed in a series circuit relationship to both of the bypass inlet of the flow balancing element and full flow inlet of the flow balancing element;
• disposing the bypass filter, the full flow filter and flow balancing element within the housing;
• connecting the full flow inlet of the flow balancing element in fluid communication in a series fluid circuit relationship with the outlet of the full flow filter;
• connecting the bypass flow inlet of the flow balancing element in fluid communication in a series fluid circuit relationship with the outlet of the bypass filter;
• and
• connecting the outlet of the flow balancing element in fluid communication in a series fluid circuit relationship with the filter outlet of the filter apparatus;
• and
• whereby at the operating temperature, the portion of fluid filtered by the full flow filter that is exiting the flow balancing element will be larger than the portion of the fluid filtered by the bypass filter that is exiting the flow balancing element, and at a predetermined temperature below the operating temperature the portion of fluid filtered by the bypass filter that is exiting the flow balancing element will be larger than the portion of fluid filtered by the full flow filter that is exiting the flow balancing element.