Fluid handling – Self-proportioning or correlating systems – Self-controlled branched flow systems
Reexamination Certificate
1996-10-28
2001-04-10
Rivell, John (Department: 3753)
Fluid handling
Self-proportioning or correlating systems
Self-controlled branched flow systems
C137S549000, C137S508000, C123S514000, C123S511000, C210S416400
Reexamination Certificate
active
06213143
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention is based on a liquid filter with a built-in pressure regulator for fuels.
A liquid filter of this kind, with a built-in pressure regulator for fuels, is known from U.S. Pat. No. 5,078,167, in which the otherwise separate components, such as the filter and pressure regulator, are combined in a common unit, of the kind known as returnless fuel systems (RLFSs). In this liquid filter, the pressure regulator functions with a diaphragm, which is acted upon by the pressure to be regulated at the outflow connector, counter to the force of a spring. A disadvantage of this liquid filter is that here the flow through the filter is from the inside outward, which can greatly reduce its service life, since dirt deposits can form bridges that reduce the inlet cross sections. This is especially critical when there are large amounts of dirt. Also, the pressure must be returned to one side of the diaphragm from the clean side of the filter, thus necessitating the formation of a chamber at the diaphragm, which is complicated. Another unfavorable aspect is that the pressure regulator is connected between the inflow connector and the tank connector, and accordingly is located entirely on the dirty side of the filter element. As a result, dirt particles can get into the valve of the pressure regulator and impair its function. In this pressure regulator, the valve itself is a component that is separate from the diaphragm, and thus this liquid filter with its pressure regulator is relatively complicated and expensive in design and requires many shaped sheet-metal parts. Moreover, this filter is designed to be installed in a tank and is poorly suited to be connected by means of lines.
A liquid filter with a built-in pressure regulator is also known from U.S. Pat. No. 4,011,848, in which the liquid filter is embodied essentially as a line-type filter, with the inflow connector and outflow connector disposed on the opposed face ends of the housing. A third connector leads radially and laterally away from the housing to the tank, in which a simple ball valve is provided as the pressure regulating valve. An additional safety valve is also associated with the outflow connector and is intended to block the connection to the tank if the fuel supply fails. Once again, in this liquid filter the pressure regulator is connected directly to the dirty side. The pressure regulator here functions without a diaphragm, and because of the ball valve used it is relatively imprecise and is vulnerable to soiling. From the standpoint of being built in, the fact that the connectors for the outflow connector and the tank connector are at right angles to one another is highly unfavorable in many applications. Furthermore, German patent document DE 42 42 242 A1 discloses a device for supplying the internal combustion engine of a motor vehicle with a fuel from a supply tank, in which several components are assembled to an aggregate. A filter element through which fuel flows axially or radially is arranged in a joint housing. It is; ring-shaped and arranged concentrically to the longitudinal axis of a fuel pump. The clean side of the filter element is connected directly with the suction connection of the fuel pump. A tubular connection branches from an outwardly expanding pressure connector of the fuel pump, and a spring loaded membrane pressure regulator which is arranged externally on the aggregate housing is connected with the tubular connection. The discharge side of the pressure regulator is unloaded to the dirty side of the filter element An integration of the pressure regulator in the filter is not provided in this aggregate.
SUMMARY OF INVENTION
The liquid filter according to the invention with a built-in pressure regulator for fuels, as defined by the characteristics of the body of the main claim, has the advantage over the prior art that with this integration of the pressure regulator in the liquid filter, an extremely simple, compact, economical design is made possible. Since the pressure regulator is acted upon by pressure fluid only from the clean side, only cleaned fuel flows through all of its components, thus precluding wear or leaks caused by trapped dirt particles. Moreover, with this design, it can be assured that the flow through the filter element is in the correct direction, from the outside inward, so that service lives as long as for a filter alone are attained. The liquid filter with the integrated pressure regulator can be installed easily and simply at any arbitrary location in the vehicle; no additional connectors on the tank are needed. The integrated design of the pressure regulator allows an especially easy-to-assemble kind of construction, which because of its economical design is even suitable for a disposable filter. The quantity of liquid flowing out when the pressure regulator responds can flow away relatively unhindered, which makes for a compact, small structural size. The threat of flow noise and pressure pulsations is considerably reduced as well, since in a distinction from pressure regulators known until now, the liquid stream is guided without major deflection and has an essentially steady course from the inlet to the outlet. The pressure regulator favorably compensates for any possible pressure drop that might be caused by clogging of the filter, because the regulating takes place on the clean side.
Advantageous further features of and improvements to the liquid filter with a built-in pressure regulator are possible by means of additional provisions For instance, as a result, the connectors for the inlet and the return flow are located on one side of the filter, so that only short hoses from the filter to the tank are needed. It is also favorable if cap of the filter housing and the pressure regulator are a component group that can be preassembled before installation, and the pressure regulator of this unit is also adjustable. It is also expedient for the clamping point, which otherwise, in external pressure regulators, is critical to tightness, to be located now in the interior of the filter housing; the filter housing itself is sealed off from the outside, and the tightness problem is thus considerably alleviated. According to further, features especially simple and compact designs are attainable that in particular lend themselves to use as a disposable filter. In further versions, the symmetrical embodiment of the filter insert makes it unnecessary to install the filter insert in a particular orientation, thus making it simpler, faster, and less expensive to produce. It is moreover attained that because of the press fit of the filter housing, filter insert and cap, a positive force on the clamping or crimping point of the diaphragm always ensues, thus lessening the threat that the diaphragm with creep outward at its outer edge. Another economical factor in the present liquid filter is that some of the housing for the pressure regulator is now replaced by the filter cap, thus omitting one expensive component that is usually made of special steel. The liquid filter with the integrated pressure regulator is also advantageously embodied such that it is suitable for being made of aluminum, steel, or plastic. The housing parts can also be separable connected, so that the filter element can be replaced by itself, leaving the rest in place. Other advantageous features will become apparent from the other claims, the description and the drawing.
REFERENCES:
patent: 4011848 (1977-03-01), Coddington
patent: 4959141 (1990-09-01), Anderson
patent: 5078167 (1992-01-01), Brandt
patent: 5433241 (1995-07-01), Robinson
patent: 5435345 (1995-07-01), Robinson
patent: 5533478 (1996-07-01), Robinson
Bueser Wolfgang
Drutu Lorenz
Liskow Uwe
Lucas Bernhard
Projahn Ulrich
Farid Ramyar
Rivell John
Robert & Bosch GmbH
Striker Michael J.
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