Fuel filters of many types are known in the prior art. A popular type of fuel filter often used in trucks and other heavy vehicles is one that has a replaceable filter element. When in use, the element is housed in a filter housing. The housing is a permanent part of the vehicle fuel system.
Periodically the filter element in the assembly should be replaced. Prior art filter designs pose several drawbacks when it is necessary to change a filter element.
A common drawback associated with changing many types of prior art filter elements is that fuel is spilled out of the system into the environment during the element change. The loss of fuel not only poses a fire risk but is also an environmental problem.
Other prior art filter assemblies are made so that the person changing the filter must have their hands in contact with the fuel. Such contact, particularly on a repeated basis, is undesirable.
A further drawback of some prior art filter housings is that when the element is changed, dirt that has collected in the housing or on the element, is suspended or falls off the element into the fuel. The dirt may migrate into the outlet of the filter housing and travel downstream in the fuel system. Such dirt may cause serious problems to downstream components such as a carburetor, fuel injection pump or fuel injectors.
U.S. Pat. No. 4,836,923, which is owned by the assignee of the present invention, discloses a fuel filter assembly that overcomes these drawbacks. The filter element of that design may be changed without spilling fuel or requiring the person carrying out the filter change to have skin contact with the fuel. Further, the fuel filter assembly is designed so that the possibility of migration of contaminants into the outlet during an element change is minimized.
While the design shown in U.S. Pat. No. 4,836,923 works well, it is a relatively expensive item to manufacture. This is because the design includes a housing with integral passages as well as a standpipe. Further cost is added through the use of an end cap for the filter element which includes an integral seal. All of these features add complexity and cost to the design.
Thus, there exists a need for a fuel filter assembly with a replaceable element that has the desirable characteristics previously discussed, but is less expensive to manufacture.