Fluid handling – With means for separating solid material from the fluid – Hollow strainer – fluid inlet and outlet perpendicular to...
Reexamination Certificate
2000-02-15
2001-08-07
Chambers, A. Michael (Department: 3753)
Fluid handling
With means for separating solid material from the fluid
Hollow strainer, fluid inlet and outlet perpendicular to...
C137S115270, C137S599140, C210S433100
Reexamination Certificate
active
06269835
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a pressure-regulating arrangement having the features of the precharacterizing clause of Patent claim
1
.
It is known (DE 42 24 981 A1) to provide the flow (pressure line) of a fuel pump with a pressure regulator whose switching threshold lies close to the maximum flow pressure. The cutoff quantity/flow is used as a driving jet for a self-priming ejector. The flow takes priority during operation. A fuel filter is often also provided in the flow from the pump, and has to keep contaminants originating from the tank away from the carburettor or injection pump
ozzles. Arrangements of this type have been tried and tested in practice.
The return flow from the injection pump has also already been used as the driving jet for the self-priming ejector. However, attempts are made as far as possible to dispense with a return line, for reasons of cost and in order to reduce possible leakage points (compliance with emission regulations). Instead, it is intended to supply the injection installation with just the amount of fuel which is actually consumed.
A combination of a pressure buffer and a fuel filter has already been proposed (earlier Patent Application 196 27 741.8). There, however, it is only indicated schematically that a chamber through which flow passes and which has a variable volume can be put together with a filter, the flow pressure is controlled as a function of the instantaneous chamber volume, so that neither a return nor a cutoff line is needed.
BRIEF SUMMARY OF THE INVENTION
The invention is based on the problem of reducing to the greatest possible extent the number of individual parts for such a pressure-regulating arrangement having a cutoff stream. According to the invention, this object is achieved with the characterizing features of claim
1
. The features of the subclaims indicate advantageous developments of this subject.
If the pressure regulator, together with cutoff line, is combined with a filter in one structural unit, these components are preassembled by the manufacturer to form a unit. During the final assembly on the production line, this unit can be installed into the fuel supply system of the respective vehicle with few operations. Additional line connections between the pressure regulator and the filter are dispensed with, so that not only is the number of parts considerably reduced, but also the amount of labour.
If the pressure regulator is arranged with the filter in a common housing which has a feed connection, a discharge connection and a cutoff connection, the filter cartridge or the filter housing is simply connected downstream of the pump and, in a dual function, provides the pressure limitation and the fine filtering of the fuel stream.
Particularly simple and rapid assembly may be achieved if all three connections are arranged on the same side of the filter housing, since it is then possible, for example, to fasten the filter housing first and then to produce the line connections on a firm base.
The pressure regulator is expediently arranged on a side of the housing that is remote from the connections, so that sufficient installation space for its components, on the one hand, and for the connections, on the other hand, is available.
It is also advantageous if the pressure regulator is arranged downstream of the filter insert. The throttling resistance of the filter insert, which increases over the long term, thus has no influence on the switching behaviour of the pressure regulator. In addition, no unfiltered fuel passes into the cutoff circuit.
A particularly compact design is produced if the cutoff line is arranged coaxially with the filter.
The common housing will preferably consist of sheet metal and be tightly closed on both sides by covers—for example by being peened over. For the purpose of the mechanical fixing of the unit, a union nut or the like may be provided in a known manner. A significant saving in assembly time is achieved if all three connections are arranged coaxially with one another, and the pressure-regulating arrangement corresponds with an appropriate connecting piece which has three corresponding ducts that can be sealed off from one another and to which connecting piece the pressure-regulating arrangement can be connected directly by being plugged on or screwed on.
Further details and advantages of the subject of the invention emerge from the drawing of an exemplary embodiment and its detailed description which follows below.
REFERENCES:
patent: 4310142 (1982-01-01), Ludwig
patent: 5078167 (1992-01-01), Brandt et al.
patent: 5402817 (1995-04-01), Bueser
patent: 5584318 (1996-12-01), Brandt
patent: 1227021 (1971-03-01), None
patent: 1257820 (1971-12-01), None
Chambers A. Michael
Mannesmann VDO AG
Mayer Brown & Platt
Speer Richard A.
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