Housing pan for supporting a fluid delivery pump

A housing pan for receiving a fluid delivery pump for a delivery aggregate for delivering fuel from a fuel tank has a pan body, a unit forming a supply opening for flowing fluid and open into an interior of the pan body, a pan bottom, a unit forming a part-ring shaped flow passage located concentrically into an axis of a pan body in an interior of the pan body at an axial distance from the pan body, the flow passage having a passage entry which communicates with the supply opening and also having a passage wall which is located inwardly in a radial direction and is provided with a plurality of throughgoing slots, the throughgoing slots being spaced from one another over a length of the flow passage and extending in a longitudinal direction of the flow passage, the throughgoing slots having lower slot edges located closer to the pan bottom and arranged at least near a passage bottom.

BACKGROUND OF THE INVENTION 
The present invention relates to a housing pan for supporting a fluid 
delivery pump, in particular for a delivery aggregate for delivering fuel 
from a fuel tank. 
A known delivery aggregate of the above mentioned type for delivering fuel 
from a fuel tank is disclosed in the German patent document DE 44 44 854 
A1. In this aggregate the delivery of fuel pump is arranged in a filter 
pan which is inserted in the housing pan closed with the flange from the 
upper side. This complete mounting unit known as an assembly unit is 
inserted in the fuel tank of a motor vehicle and mounted on its bottom. 
The housing pan is always filled with fuel from the inner chamber of the 
tank through a supply opening the fuel pump aspirates fuel from the 
housing pan through a filter arranged at its suction side in the filter 
pan and pumps it to the internal combustion engine through a delivery 
conduit which is connected at its pumping side. A consumed fuel which is 
not consumed flows through a return conduit again to the housing pan. The 
fuel return flow is used also for operation of a suction jet pump which 
delivers the fuel from the fuel tank into the housing pan through the 
supply opening, so that the fuel level in the housing pan is always 
maintained at the same level, even when the fuel level in the fuel tank is 
lowered below it. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide a housing 
pan for supporting a fluid delivery pump, which avoids the disadvantages 
of the prior art. 
More particularly, it is an object of present invention to provide a 
housing pan for supporting a fluid delivery pump which has the advantage 
that dirt particles contained in the fluid are efficiently withdrawn and 
retained far from the suction side of the fluid pump, so that the 
conventionally available filter is not dirtied fast and a filter exchange 
for exchanging the clogged filter is needed only in substantial time 
intervals. 
In keeping with these objects and with others which will become apparent 
hereinafter, one feature of present invention resides, briefly stated, in 
a housing pan of the above mentioned type, in which a partially 
ring-shaped flow passage is formed in the interior of the pan at an axial 
distance from a pan bottom, a passage entry communicates with the supply 
opening, and a passage wall located inwardly in a radial direction has a 
plurality of throughgoing slots which are arranged so that they are spaced 
from one another over a passage length and extend in a longitudinal 
direction of the passage, and the throughgoing slots have slot edges which 
are located closer to the pan bottom and arranged on or near the passage 
bottom. 
When the housing pan for supporting a fluid delivery pump is designed in 
accordance with present invention, it eliminates the disadvantages of the 
prior art and provides for the above mentioned highly advantageous 
results. 
The dirt particles contained in the fluid deposit, because of their force 
of gravity independence of their specific density relatively fast on the 
passage bottom of the inventive flow passage. They are transported from 
here by a secondary flow which is formed in the flow passage, through the 
throughgoing slots on the inner passage wall, and finally are deposited 
under the flow passage in a deposit chamber formed on the pan bottom. The 
cause of the secondary flow which is formed on the merdional plane of the 
flow passage is the radial pressure gradient which is produced by the 
centrifugal force of the fluid elements in the interior of the passage. 
The longitudinally flowing fluid elements in the wall limiting layers are 
subjected to this pressure gradient and therefore transported in the 
interior of the passage. 
In accordance with a preferable embodiment of the present invention the 
flow passage and the deposit chamber for the dirt particles limited by the 
pan bottom is formed by the wall regions of the pan bottom and the pan 
casing and a pan insert inserted in the interior of the pan. 
A ring projection which extends on the inner wall of the tank casing to the 
pan bottom radially has a surface which forms the passage bottom and is 
formed of one piece. The insert has a flat bottom which limits the deposit 
chamber from above and a wall web which axially projects upwardly along 
the bottom edge and forms the inner passage wall of the flow passage. 
Since the flow passage and the deposit chamber are formed as two 
separately manufacturable parts, there is a substantial manufacturing 
advantage which lowers the production cost of the housing pan. 
The novel features which are considered as characteristic for the present 
invention are set forth in particular in the appended claims. The 
invention itself, however, both as to its construction and its method of 
operation, together with additional objects and advantages thereof, will 
be best understood from the following description of specific embodiments 
when read in connection with the accompanying drawings.

DESCRIPTION OF PREFERRED EMBODIMENTS 
A housing pan 10 in accordance with present invention is shown in FIG. 1 in 
a longitudinal section. It operates for receiving a fluid delivery pump 
and also, in its preferable embodiment, a delivery aggregate for 
delivering fuel from a fuel tank to an internal combustion engine, which 
is identified as a tank insert. It includes, in addition to a housing pan, 
also a fuel delivery pump and a filter pan which receives the delivery 
pump and is provided with a prefilter and a main filter. Such a delivery 
aggregate is disclosed for example in the German patent document DE 44 44 
854 A1. The filter pan is inserted with integrated delivery pump as well 
as with pre and main filter, into a housing pan 10. The thusly finished 
housing pan 10 is mounted in the fuel tank, so that a supply opening in 
the housing pan 10 makes possible the fuel flow from the fuel tank into 
the interior of the housing pan 10. 
FIG. 1 shows a pan bottom 11 and a lower part of a cylindrical pan wall 12 
of the housing pan 10. The suction pipe of the fuel delivery pump is 
identified as 13. A prefilter mounted at the filter cup at its end side is 
identified with 14. The delivery pump sucks fuel through its suction pipe 
14 and the prefilter 13 from the housing pan 10 and pumps it to the 
internal combustion engine. There fuel which is not consumed is supplied 
in a known manner again to the fuel tank through fuel return conduit. The 
fuel return flow is used for operating a suction jet pump, with which fuel 
is brought from the fuel tank through the supply 15 into the housing pan 
10. The fuel inflow actuated by the suction jet pump through the supply 
opening 15 is identified in FIG. 2 with a set of arrows 16. 
In order to provide an efficient separation of dirt particles from the fuel 
which fills the housing pan 10 and hold them far from the prefilter 14 of 
the filter pan and therefore to guarantee a low dirt particle loading of 
the delivery pump and reduction of wear sensitivity the fuel supply is 
performed by the suction jet pump through a partial-ring-shaped flow 
passage 17 formed in the interior of the housing pan 10. The flow passage 
17 is arranged concentrically to an axis 101 of the pan. The flow passage 
17 is formed on the inner wall of the pan casing 12 at an axial distance 
from the pan bottom 11 and extends over a peripheral angle which is more 
than 180.degree.. A supply opening 15 is formed at the passage entry, 
while the passage end opens freely into the pan interior. 
As can be seen from FIGS. 1 and 2, an outlet slot 18 is formed in the 
passage end. It extends in the axial plane of the housing pan 10 or in an 
approximately parallel plane. A passage wall 171 which is located inwardly 
in a radial direction is provided with a plurality of throughgoing slots 
19 which are spaced over the length of the passage from one another. They 
extend in the longitudinal direction of the passage, and their lower slot 
edges 191 located near the pan bottom 11 are provided directly at the 
passage bottom 172. As can be seen from FIG. 1, the width of the 
throughgoing slot 19 in direction of the pan axis 101 is very much smaller 
than the axial height of the flow passage 17 as seen in direction of the 
pan axis 101. 
The dirt-loaded fuel picked up by the suction jet pump is supplied through 
the curved flow passage 17 to the outlet slot 18. Because of the passage 
curvature a pronounced secondary flow is produced in the meridional plane 
as identified with the arrows 20 in FIG. 1. The cause of the secondary 
flow is the radial pressure gradient which is caused by the centrifugal 
force of the fluid elements in the interior of the passage. The slowly 
flowing fuel elements in the wall limiting layers are subjected to this 
pressure gradient and thereby transported to the interior of the passage. 
The dirt particles which are available in the entering fuel jet with a 
density greater than 1.5 kg/dm.sup.3 are deposited, due to the force of 
gravity in dependence on the density relatively fast on the passage bottom 
172. From there, the dirt particles, because of the secondary flow, are 
withdrawn through the throughgoing slots 19 into an inwardly located 
deposit chamber 22 and therefore no longer can reach the prefilter 14 of 
the delivery pump. The wall-close flow line coarse in the flow passage 17 
is identified in FIG. 2 by the arrow 21. The deposit chamber 22 is located 
due to the formation of the flow passage 17 at an axial distance from the 
pan bottom 11 and is limited from below by the pan bottom 11. 
In all embodiments of the housing pan 10, the flow passage 17 on the one 
hand and the deposit chamber 22 on the other hand are formed by wall 
regions of the pan bottom 11 and the pan casing 12 as well as by wall 
regions of a pan insert 23 inserted in the interior of the pan. For this 
purpose a radially inwardly projecting ring projection 24 which is 
provided on the inner wall of the pan casing 12 and extends to the pan 
bottom 11 is formed as a one-piece element. Its surface which faces away 
from the pan bottom 11 forms the passage bottom 172. The ring projection 
24 extends with the constant radial width with the same peripheral angle 
as the flow passage 17. At the passage end, the radial width for forming 
the outlet slot 18 is very small, in order to maintain the predetermined 
constant radial width again at the canal entry. An axially upwardly 
projecting web portion 27 extends along the circular-ring-shaped upper 
inner edge 241 of the ring projection 24 which faces away from the pan 
bottom 11. It is located in the region of the flow passage 17 and is 
formed as once-piece element. The web portions are spaced from one another 
along the length of the throughgoing slot 19 at a predetermined distance 
and are formed so that they are flush with the inner edge 241. 
The top insert 23 which is shown in FIG. 3 in section and in FIG. 4 on plan 
view, separately from the housing pan has a flat bottom 25 and a wall web 
26 which projects axially and upwardly along the outer bottom edge 252. It 
is curved outwardly so that the end of the wall web 26 lies on an outer 
diameter which is smaller than the inner diameter of the pan casing 12. 
While the pan insert 23 is rotation-symmetrical relative to its wall web 
26, the bottom 25 in the region of the outlet slot 18 has a lug-shaped 
projection 251 as identified with broken contour in FIG. 4. 
In the region of the wall web 26 which follows the projection 251, a 
throughgoing opening 30 is provided so that the ring passage flow can 
reach the inner region of the pan insert 23 which is limited by the bottom 
25 and the wall web 26. After insertion of the pan insert 23 into the 
housing pan 10, the flat bottom 25 of the pan insert 23 limits the deposit 
chamber 22 from above. The curved wall web 26 extending approximately with 
a gap distance to the inner wall of the pan casing 12 forms an inner 
passage wall 171 and an upper wall region 173 of the flow passage 17. 
Thereby, a flow passage 17 is produced so that it is substantially closed 
around and has a supply opening 15 the outlet slot 18, and the 
throughgoing slots 19 provided on the inner passage wall for the dirt 
particle withdrawal in the deposit chamber 22. The throughgoing slots 19 
are defined by web portions 27 on the ring projection 24 and by the bottom 
25 of the pan insert 23 sitting on the ring projection 24. 
The embodiment shown in FIGS. 5 and 6 deals with a modified housing pan 10 
which differs in that the flow passage 17 is not closed, but instead is 
upwardly open. Thereby a weakened secondary flow is produced in the flow 
passage 17 as identified with arrow 20. For reinforcement of the carrying 
away mechanism for the dirt particles contained in the fuel, a throttle 28 
formed as a single opening is provided in the deposit chamber 22. 
Therefore a flow is set between the interior of the pan and the 
surrounding area of the pan, or in other words the fuel tank. The flow 
passage 17 is formed by means of the pan insert 22, whose ring-shaped wall 
web 26 extends only in the axial direction and no longer has a curvature 
leading toward the pan casing 12. The flat pan bottom 25 also has the 
lug-shaped projection 251 in the region of the outlet slot 18. The 
construction of the pan insert 23 with the throughgoing opening 30 in the 
region of the wall web 26 extending on the projection 251 is shown in 
FIGS. 7 and 8. As for the remaining aspects, the housing pan 10 of FIGS. 5 
and 6 corresponds to the housing pan of FIGS. 1 and 2, so that identical 
components are identified with the same reference numerals. 
The embodiment of the housing pan 10 shown in FIGS. 9 and 10 differs from 
the housing pan 10 of FIGS. 1 and 2 in that the meridional outlet slot 18 
at the passage is dispensed with. Therefore here both the ring projection 
24 and also the pan insert 23 shown in FIGS. 11 and 12 are formed as 
rotation-symmetrical shapes. The bottom of the pan insert 23 is identified 
as 25, the wall web as 26, and the throughgoing opening for the ring 
passage flow available in the wall web 26 is identified as 30. Moreover, 
the throughgoing slots 19 in the inwardly located passage wall are not at 
the pan side, but instead are located at the insert side. For this 
purpose, web portions 29 are formed of one piece at the lower side of the 
bottom 25 of the pan insert 23 along the outer bottom edge in FIG. 11. The 
web portions 29 are spaced from one another and located flush with the 
circular-ring shape bottom edge. The web portions 29 together with the 
outer surface of the ring projection 24 limit the throughgoing slot 19. 
The throttle 28 for reinforcing the carrying away mechanism for the dirt 
particles shown in FIG. 5 can be provided both in the embodiment in FIGS. 
9 and 10 and in the embodiment of FIGS. 1 and 2. 
It will be understood that each of the elements described above, or two or 
more together, may also find a useful application in other types of 
constructions differing from the types described above. 
While the invention has been illustrated and described as embodied in 
housing pan for supporting a fluid delivery pump, it is not intended to be 
limited to the details shown, since various modifications and structural 
changes may be made without departing in any way from the spirit of the 
present invention. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic or specific aspects of this invention. 
What is claimed as new and desired to be protected by letters patent is set 
forth in the appended claims: