Fluid Filtration Apparatus and Method

摘要

An apparatus and method for filtering a liquid utilize a filter apparatus including a bypass filter, a full flow filter, and a flow balancing element for dividing a total inlet flow of fluid to the filter apparatus into a bypass portion, passing through the bypass filter, and a full flow portion, passing through the full flow filter. The bypass filter has a lower filtering efficiency than the full flow filter element, so that a venturi tube is not required for causing the bypass portion to pass through the bypass filter. The flow balancing element divides the flow into a desired bypass portion and a desired full flow portion, at a predetermined operating temperature. Below the operating temperature, the bypass portion increases and the full flow portion decreases, the bypass portion becoming greater that the full flow portion at a second predetermined temperature below the operating temperature.

主权项

1. A filter apparatus, comprising:
a housing having a closed end and an open end, joined by a cylindrical sidewall defining a longitudinal axis extending from the closed end to the open end of the housing; a bypass filter, disposed within the housing adjacent the open end of the housing, having an outer periphery thereof spaced inward from the sidewall of the housing to form a space around the bypass filter for passage of fluid between the bypass filter and the sidewall, the bypass filter also having an inner periphery thereof forming an axially oriented through-bore of the bypass filter, the bypass filter further including a bypass filter media disposed between the inner and outer peripheries of the bypass filter, the bypass filter media having a bypass filter efficiency for removing particles of a given size from a fluid flowing radially inward through the bypass filter media from the space around the bypass filter to the central through-bore of the bypass filter; a full flow filter, disposed within the housing, adjacent the closed end of the housing, having an outer periphery thereof spaced inward from the sidewall of the housing to form a space around the full flow filter for passage of fluid between the full flow filter and the sidewall, the space between the full flow filter and the sidewall being connected in sealed fluid communication with the space between the bypass filter and the sidewall of the housing, the full flow filter also having an inner periphery thereof forming an axially oriented through-bore of the full flow filter connected in sealed fluid communication with the through-bore of the bypass filter, the full flow filter further including a full flow filter media disposed between the inner and outer peripheries of the full flow filter and having a full flow filter efficiency for removing particles of the given size from a fluid flowing radially inward through the full flow filter media from the annular space around the full flow filter to the through-bore of the full flow filter, with the full flow filter efficiency being higher than the bypass filter efficiency for removing particles of the given size; 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; 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.