Recirculating lubricating system with monitor filter unit

Claim 1

A recirculating lubricating system comprising a sump for lubricating oil, a pump adapted to pump oil from the sump, a main filter element, a monitor filter unit disposed between the pump and said main filter element, passageway means interconnecting said pump, monitor filter unit and main filter element whereby oil is pumped from the sump through the monitor filter unit and the main filter element to a plurality of lubricating points from where the oil drains back to the sump, said monitor filter unit including a generally tubular body portion having end portions adapted for connection into said oil flow passageway, a removable monitor filter element located in a hollow boss formed integral with said body portion and between an inlet chamber and an outlet chamber, and diverting means comprising a longitudinal protrusion extending into said body portion and having an inlet opening facing in a direction opposite the normal direction of flow of the lubricating oil whereby a proportion of the oil flowing between the pump and the main filter element is diverted to flow through the inlet chamber, the monitor filter element and said outlet chamber to be returned to the flow of oil upstream of the main filter element.