Spin-on filter coalescer unit with flow reversing baffle assembly

A spin-on filter coalescer unit having a flow reversing assembly. The filter-coalescer unit includes a cylindrical body which contains an annular filter element surrounded by a coalescing element, and a final separation stage is spaced radially outward of the coalescing element. A cover encloses the open end of the body and is provided with a central outlet port and a plurality of circumferentially spaced inlet ports. The flow reversing assembly comprises a pair of baffle members, one of which can be the cover, which are spaced apart to define a chamber that communicates with the outlet. A plurality of tubular connecting members form sealed conduits extending through the baffle member and establish communication between the inlet ports and the central axial passage within the filter element. Liquid entering the unit through the circumferentially spaced inlet ports flows through the tubular connectors and into the central passage, and then outwardly through the filter and coalescer elements and separation stage to the outer circumferential passage between the separation stage and the body, and then axially through the circumferential passage for discharge, via the chamber between the baffle members, through the outlet.

BACKGROUND OF THE INVENTION 
Fuel-water coalescers are commonly used in fuel systems to remove entrained 
water from hydrocarbon fuels. The removal of water is particularly 
important in diesel and gas turbine engines where entrained water can 
seriously reduce service life of fuel injectors and pumps. The typical 
coalescer includes an annular coalescing element formed of a series of 
superimposed layers of fibrous material constructed in a manner to allow a 
graded particle capture. The flow direction is from the inside-out, which 
creates a decrease in velocity as the diameter of the element increases. 
The decrease in velocity aids in coalescing the fine water droplets into 
larger globules that will fall by gravity along the outer surface of the 
element to the bottom of the unit for collection. 
On the other hand, fuel filters used for trapping contaminants and 
particulate matter have traditionally utilized an outside-in flow. The 
outside-in flow provides a greater surface area on the outside of the 
element which reduces the tendency for the element to clog. 
It may be desirable at times to substitute a coalescer or a combined 
filter-coalescer for the conventional filter. If the filter is connected 
to the engine block by connecting hoses, the change to the coalescer can 
be readily made by reversing the lines to the coalescer. However, most 
current fuel filters are of the spin-on type in which the filter is 
threaded into the engine block so that a simple hose line conversion to a 
coalescer cannot be made. In situations such as this, reversing the flow 
to accommodate the coalescer has been achieved by utilizing a flow 
reversing adapter which is positioned between the engine block and the 
spin-on coalescer. However, auxiliary adapters are expensive to produce, 
double the potential for leaks and take up valuable space that could 
otherwise be alloted to filtering or coalescing media. In addition, the 
use of an adapter makes it difficult to use the original filter element in 
conditions of emergency. 
SUMMARY OF THE INVENTION 
The invention is directed to a filter-coalescer unit having an improved 
flow reversing baffle assembly. 
In accordance with the invention, the flow reversing assembly includes an 
outer baffle, which can either be the cover of the filter-coalescer unit 
or a separate baffle located beneath the cover, and is formed with a 
central outlet opening. An inner baffle is spaced from the outer baffle to 
define a chamber therebetween and connected to the outer baffle by a 
plurality of tubular connecting members which form sealed conduits that 
extend through the spaced baffles and establish communication between the 
inlet in the unit and an axial passage within the annular filter-coalescer 
element. 
By virtue of this assembly, liquid entering the unit flows through the 
tubular connecting members into the central passage within the 
filter-coalescer element. The liquid then flows outwardly through the 
element to the outer circumferential passage adjacent the casing and then 
axially through the circumferential passage for discharge via the chamber 
between the baffles, thus resulting in a reversal of flow from outside-in 
to inside-out. 
The baffle assembly can be manufactured from inexpensive sheet metal 
stampings and is more compact than the prior art external adapters, thus 
allowing more interior space to be allocated to filter or coalescer media. 
The placement of the baffle assembly inside the coalescer cover also 
eliminates the potential filter-to-head leaks that were present with the 
use of external adapters.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The drawings illustrate a filter-coalescer unit 1, having a flow reversing 
baffle assembly. The filter-coalescer unit 1 includes a cylindrical 
container or body 2 and an annular filter-coalescer element 3 is disposed 
centrally within the container 2, while a final separator element 4 is 
spaced outwardly of the filter-coalescer element 3. The unit 1 also 
includes a cover 5 which is crimped to the outer end of body 2 and has a 
central outlet port 6 and circumferentially spaced inlet ports 7. 
The filter-coalescer element 3 is a conventional type and, in general, 
includes an inner pleated filter 8 and an outer fibrous, multi-layer 
coalescer element 9. The separator element 4 is formed of water repellant 
pleated paper. Both the filter-coalescer element 3 and separator unit 4 
are disposed between an upper ring member 10 and a base ring member 11. A 
spring 12 engages base ring 11 and urges the filter coalescer element 3 
and separator element 4 into contact with the flow reversing baffle 
assembly 13. The disposition of filter-coalescer element 3 and separator 
element 4 inside container 2 is such that they define an axial passage 14 
and an outer circumferential passage 15. 
The flow reversing baffle assembly 13, located between cover 5 and upper 
ring member 10, consists of an outer baffle 16, an inner baffle 17 and 
tubular connecting members 18. Upper gasket 19 seals outer baffle 16 to 
cover 4, while lower gasket 20 seals inner baffle 17 to upper ring 10. 
Outer baffle member 16 has a diameter substantially equal to the inner 
diameter of body 2 and includes a centrally located outlet 21 and 
circumferentially spaced inlets 22. Outlet 21 and inlets 22 communicate 
respectively with outlet port 6 and inlet ports 7 of cover 5. 
Inner baffle 17 has a diameter somewhat less than the inner diameter of 
body 2 so as to define a corridor 23 which communicates with 
circumferential passage 15. Baffle 17 includes a plurality of outwardly 
projecting spacers 24 and circumferentially spaced holes 25 located so as 
to align with inlets 22 of outer baffle 16. Spacers 24 engage the inner 
surface of outer baffle 16 and define a chamber 26 between outer baffle 16 
and inner baffle 17. 
Tubular connecting members 18 connect the aligned holes 22 and 25 and have 
their edges deformed outwardly in order to provide sealed conduits 27 
across chamber 26. 
In use, the threaded outlet port 6 of cover 5 is spun onto a threaded 
nipple (not shown) of an engine block and the inlet ports 7 align with 
corresponding ports (not shown) on the engine block. Gasket 28 on cover 5 
engages the engine block and prevents leakage at the junction. 
As is shown by the arrows in FIG. 1, the liquid from the engine block 
enters inlet ports 7, flows through the sealed conduits 27 formed by 
tubular connecting members 18 and is directed into axial passage 14. The 
liquid then passes through filter-coalescer element 3 and separator 
element 4, longitudinally in circumferential passage 15 to chamber 26 for 
return to the engine block via outlet port 6. The use of the baffle 
assembly thus results in an inside-out flow rather than the customary 
outside-in flow. 
FIGS. 5 and 6 illustrate a modified form of the invention in which the 
cover serves as one of the baffles in the flow reversing baffle assembly. 
In the structure shown in FIGS. 5 and 6, the filter-coalescer unit 
includes an open end outer body or casing 28 which houses a 
filter-coalescer element 29 and an outer separator element 30, similar in 
construction and function to the filter-coalescer element 3 and separator 
element 4, previously described. 
The filter-coalescer element 29 and separating element 30 are retained 
between an upper ring 31 and a lower ring, not shown, and the peripheral 
edge of the upper ring 31 is spaced from the body 28 to provide an annular 
passage 32. 
The open end of the body 28 is enclosed by a cover 33, the outer edge of 
which is crimped to the end of the body. Cover 33 is provided with a 
circular groove 34 which receives a gasket 35 that is adapted to engage 
the engine block to seal the joint between the engine block and the 
filter-coalescer unit. The central portion of the cover 33 is formed with 
a threaded outlet 36 which is adapted to be threaded onto a nipple on the 
engine block. 
In addition to the cover or baffle 33, the flow reversing baffle assembly 
includes an inner baffle 37 which is spaced from cover 33 to define a 
chamber 38 that communicates with the outlet 36. A plurality of tubular 
connecting members 39, similar to connecting members 18, interconnect the 
cover 33 and baffle 37 and provide sealed conduits 40. 
As shown in FIG. 6, the peripheral edge of the inner baffle 37 is spaced 
from the body 28 to provide a passage 41 and the inner surface of baffle 
37 is sealed to the upper ring 31 by the annular seal 42. 
With the construction shown in FIGS. 5 and 6, the tubular connecting 
members 39 are aligned with outlet ports in the engine block, so that the 
fuel will enter the filter-coalescer unit through the connecting members 
39 and then flow into the central passage 43 defined by the 
filter-coalescer element 29. After flowing outwardly through the 
filter-coalescer element 29 and the separator element 30, the fuel will 
flow longitudinally through the outer passage 44, through passages 32 and 
41 and into the chamber 38 for discharge through the central outlet 36. 
The construction shown in FIGS. 5 and 6 provides a simple and inexpensive 
flow reversing assembly which changes the customary outside-in flow to 
inside-out flow. In this construction, the cover of the unit constitutes 
one of the baffles of the flow reversing baffle assembly, thereby further 
reducing the overall cost of the unit. 
While the above description has shown the flow reversing baffle assembly 
associated with a filter-coalescer unit, it is contemplated that the flow 
reversing assembly can be used with various other types of separating 
units in which contaminants, such as particulate matter, water and the 
like are removed from a liquid. 
Various modes of carrying out the invention are contemplated as being 
within the scope of the following claims particularly pointing out and 
distinctly claiming the subject matter which is regarded as the invention.