Note: Descriptions are shown in the official language in which they were submitted.
~53151~ :
BACKGROIJND OF l'I-IE INV13N~ION
In 1973, there wer~ approxi~nately one million, two hundred
thirteen thousand (1, 213, ~)00) ~mall boats, which would have a length of
less than sixty-five (65! feet, in ~anada and the United States as deter~
mined by the United States Coast, Guard and State Marine Registrie~ that
have inboard engines. Ihe present invention is designed to be uaed with
these small boats having inboard eIlgines, to remove the oil from the
bilge water and other water that is discharged overboard by the boats to
prevent pollution of the environment,
'rhe Federal Water Pollution ~ontrol Act (FWPCA) prohibits
the discharge of oil or hazardous substances into the waters of the United
States. lhis prohibition is stated in terms: "discharge" includes spilling,
leaking, pumping, pouring, or dumping; and "oil" means any kmd of oil
in any form, including fuel oil, gasoIine, lubricating oil, and pil mixed
with water in a vessels bilge. ~he United States Coast Guard and
Enviy onmental Protection Agency Standards states that oil has been dis -
charged in a harmful quantit~ if it causes a visible shinning rainbow or
discoloration of the surface of thewater.
At the present time, boats with inboard engines commonly
have bilges that collect water, fuel oil, gasoline, and lubricating oil,
.,
For safety purposes, a bilge pump is operated to pump this mi~ture over-
board prior to starting oE the engine, and during operation of the engine,
the bilge pump IS perlodically operated to further remove the combination
~- of bilge water and oil.~ ~ommonly, this will result in the discharge of a
harmful quantity of oil a~ determined by the above standards.
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One way that has been suggested to rneet the above standards
is to provide a holding tanlc within the boat, into which the bilge water
and oil is pumped during operation of the boat, so that upon docking, the
bilge water with oil will be pumped to an onshore system. For safety
reasons, the bilge water and oil must be removed from the engine com-
partment in some manner during operation and during start-up of the engine
to prevent explosions and fires.
Large oil, water separaters have been provided for large ships,
but the size and cost of these systems generally prohibit their use on small
recreational boats and snnall commercial boats of the type described above.
Further, such systems are mainly concerned with recovering bulk oil and
not with removing small quantities of oil, so that they would no doubt be
incapable of meeting the above standards. Further, such systems could not
operate with a conventional small boat bilge pump, becaùse such pumps are
extremely sensitive to back pressure and the pumps would fail to start-up,
so that their associated motors would quickly burn out and a general failure
of the system would result. Bilg~e pumps for small boats are manufactured
to pump a Yolume of liquid within the range of three hundred (300) gallons
per hour to one thousand four hundred ( 1, 400\ gallons per hour. Normally,
., ,
there is one pump for each boat, depending upon the size of the boat and the
compartmentation of the bilge-ballast area. ~hese bilge pumps are cornmonly
used with small boats having inboard engines, which include the following
types: inboard, houseboat, inboard-out drive, yacht, and commercial.
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5V~R,~ THE INVENTION
The present inVention relates to a ~iltering system for ~:
removing small quantities of oil from water, particularly for use
with small boats,
More speci~ic~lly the in~ention consists of a boat
having an outboard propeller, an inboard engine for driving the
outboard propeller, a compartment containing the engine and col- -
: lecting bilge water and oil from the engine~ a bilye pump having
an inlet adjacent the lower portion of the compartment
for sucking bilge water and oil and ~ischarging it at
a higher pressure, a filter connected to the bilge .
pump for receiving the pressurized bilge water and oil
and for normally removing the oil from the bilge water and
discharging only bilge water, and discharge means
connected to the filter for receiving the iltered
bilge water and discharging the filtered bilge water
outside of the compartment to the environment surround~
ing the boat, the filter including a housing having an
inlet and an outlet for fluid, fluid distribution means `
within the housing for directing fluid along a predeter-
mlned path between the inlet and the outlet, a first
. mass of particles within the housing and in said path,
substantially all of the particles being of a size
within a predetermined range of sizes and being of an
expanded open-pore oleophilic and hydrophobic synthetic
; ~ resin, a secon~d mass of particles within the housing,
:~ in said path and spaced in the direction of flow from
the first mass, substantially all of the particles of
the second mass being of a size within a range o~
sizes of which the upper limit is equal to or less ~; :
than the lower limit of the range of sizes of the
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pa~ticles of the ~irst rn~ss o~ p~rticles ~nd bein~
of expanded open.pore oleophilic and hydrophobic syn-
tl~etic resin, ~he second mass of particles being dis- -
posed in said path between the particles of the first ~ ;~
mass and the ou~let so that the first mass of particles
will constitute means to distribute the fluid trans-
versely of the path for even distribution and the first ~ ~ ~
and second masses of particles will constitute means ~ ~ `
to remove the oil from t~le bilge water while passing
the bilge water, and porous means positioned in said ;
path between the second mass of particles and the out~
let with a plurallty of through passages smaller in size
than the lower limit of the range of sizes of the
particles of ~he second mass for passing the filtered
bilge water and blocking passage of the particles of
the second mass. ~;
or purposes of law enforcement and routine maint-
enance, a visual indicator can be provided at the discharge end
of the system, where the clean water is discharged overboard.
The indicator will include a material that will pick up the oil
and change in color, so that when the filter fails upon being
saturated with oil, the oll that is then passed through the ~ilter
will quickly discolor the indiaator to show that the filter should
be replaced. ~;
With the above-mentioned system, under actual test
conditions, it has ~een shown that the water discharged overboard ;
leaves no visible sheen, rainbow, film or discoloration of the `~
surface vf the open water. In addition, the water pumped over-
board meets the United States Coast Guard and Environmental
Pollution Agency Standard in which the oil is removed to at
least ten (10) parts per million. ~ ~;
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BRIEF DES RI~TION OF T~ DMNING
~ urther ob~ec~s, f~atures and advantages of the
present lnvention will ~ecome more clear from the following
detailed description o~ a pre~erred embodiment, as shown in
the accompanying drawing, wherein:
FIGURE 1 is a cross-sectional, somewhat schematic,
view o~ a small boa~ employing the features of the present
invention;
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,,~ ., ~ . -. . - .. , .. . .. , :
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Fl~;URE 2 is a longitudinal cross section through a dispos-
able fil~er of the present invention;
FIGURE 3 is a longitudinal cross sectional view taken through
a permanent filter housing containing therein a disposable filter cartidge,
that would be used in place of the filter as shown in Figure 2 for the com-
bina$ion of Figure l;
FIGURE 4 is a cross sectional view t~en through the visual
indicator that is schematically ~hown in Figure l; and
FIGIJRE S is a cross sectional view taken through the relief
valve that is schematically shown in ~igure l.
The preferred embodiment of the present invention i~ designed ~,
to be used in combination with small boats with inboard engines, with smaLl
boats being defined as commercial and recreational boats having a length
-I generally less than sixty~five (65) feet, which boats have problems peculiar
to their size. According to the broader aspects of the present invention,
the fluid eystem may be used wi~h a standard filtration systern for a swim~
- ` . ...
ming pool to remove the oils normally found in swimming pool water from ~ ~
.
~, sources such as sun tan lot1on, and normal body oils, which oils tend to
promote the growth of algae that will discolor the water and require higher
., . ~ 20 concentrations of chlorine or similar material.
With respect~to the preferred embodiment as shown in Figure 1,
only a portion of a small boat is ~hown, because the boat may be OI any
,,
small boat design and the actual design ~ the s}nall boat forms no part oi
i the present invention. ~he small boat includes a hull 1 that extends partially ,
above the normail water line 2 and partially below the normal line . For ~ ~
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propulsion of the boat, there is a driven propeller 3 below the water line,
which is drivingly connected to a drive shaft 4 that passes through the
hull 1 and is conne~ted at its inboard end to an inboard engine 5 rrhe
engine 5 is mounted within an engine compartment 6, which in the particu-
lar example of a boat design is formed by the hull 1 and a partition 7.
In a conventiorlal manner, bilge water and oil :erom the engin~ is collected
in the bottom of the engine compartment 6, which oil may be obtained from
bearing grease, engine lubricating oil leakage, gasoline leakage, and the
like. In a conventional small boatJ the bilge water and oil is pump over-
board by a bilge pump prior to starting the engine, to remove the hazards
of an explosion or fire caused by igniting s)f the oil that is mixed with the
:~ bilge water~ and further the bilge pump i9 conventionally operated when-
'~ ever needed to remove bilge water and oil during operation of the engine.
According to the present invention, the bilge pump 8 has an
'I .:
inlet connected to an inlet pipe 9 that extends from the bilge pump 8 to
closely adjace~t the lower most portion of the engine compartment, so ~ :
that the bilge pump 8 may suck bilge water and oil into the pump and dis- ~:
charge the same at a higher pressure through a pump outlet 10. Yhe
. pump outlet 10 is fluid connected to a pressure relief valve 11, which is
more fully shown in Figure 5, which will maintain the pressure of the
bilge water and oil passlng through the bilge pump outlet 10 without dis- ~:
charging the bilge water a~d oil into the engine compartment during normal
~,
operation of the pump, and further which will permit relief of this pressure
at the pump outlet 10 when the pllmp is shut down, ~he relief valve 11 is
, so constructed that it will vent the pump outlet 10 to the atmosphere within
the engine compartment after i;he pump has been shut down and during ~;
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~V53~LS~3
start-up of th~ pump, that is, the relief valve 11 will not cloisie until after
normal pressure has been obtained at the pump outlet 10 ais a reisult of
ormal pump operation or rated speed of the motor (not shown) drivingly
connected to the pump.
After lieaving the vicinity of the back pressure relief valve 11,
the pumped high pressure bilge water and oil travels to the filter 12 that
may be of the type shown in Figure 2 or shown in Figure 3J where the
bilge water and oil entering the inlet 13 will be filtered so that only hilge
water will leave under presstlre through the filter outlet 14 until such time ;~
ais the filter 12 becomesi saturated with oil. rrhe thus filtered bilge water, :
- which is now clear of oil, will enter the inlet 16 of an indicator 15, to leave
the indicator at 17 for discharge through the c>utboard nozzle 18. ~he indi-
cator 15, which is more fully shown in Figure 4, includes a materlal that
will discolor or change in color whcn it is in contact with small quantities
of oil, which color will be visible from the exterior of the boat to give an
indlcation that oil isi passing through the filter, which occurs as a result of
saturation of the filter. With the present invention under actual tiests, a
normal filter should last one (1) boating season, and if the boat is used year- .
"
round, two filters may be required. ~he indicator will provide an indication . ` ~ I .
1 20 I;o the boat owner or operater that the filter needs changing, and it will also
~ provide an indication to law enforc~ment agencies that the boat is discharging : :
a ~ignificant amount of oil overboard, even though the bilge pump may not
be working at the tirne the inspection i~ ma~e. ~ .
A dispo~able filter 12 is shown in more detail in Figure 2,
~` wherein there is provided a one piece housing 19 that is preferably molded
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from a synthetic resin so as to provide at one end a nipple that may be
used as either the inlet 1~ or the outle 14 of the filter unit, which may
in tUrrl be provided with internal or external threacls, or external ridges
to engage a hose clamped about the nipple, which securement features
are not shown since they may be of any conventional type. ~he other end
of the housing 19 is closed by means OI an end plate 20 that may be heat
sealed or otherwise bonded to provide a fluid tight conneetion with the
housing 19. ~he end plate 20 further has an integral nipple that may
provide the inlet connection 13 or the c,utlet connection 14, in a corresponding
10 manner. Preferably, l;he end plate 20 is molded in one piece from a synthetic
resin or metal. ~he material that fills the interior of the chamber formed
by the housing 19 and end plate 20 is of a construction that is symetrical
with r espect to the opposed ends, so that the filter is reversible in install -
ation to simplify installation and to simplify construction. Immediately
, adjacent each end, there is a layer of a sheet of synthetic resin foam that
will freely pass both oil and water, preferably without absorption of the
oil to any material extent Immediately adjacent and to the interior of the
sheet foam layer 21, there is a deflector or baffle plate 22J that is pre-
ferably formed by a solid sheet of synthetic resin having a plurality Oe
; 20 axially extending holeg or perforations, which plate in combination with
the sheet foam will provide for even distribution of the liquid across the
entire extent of the sheet, that is, the liquid entering the inlet 13 will be
dispersed radially outward for even distribution across the entire cross-
section of the housing 19. Again, the oil and water will pass through the
. . . . .
plate 22J without any significant retention. l~he fluid will then pass through
alternate layers of large partlcle e~panded synthetic resin 23 and small
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lOS~
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particle expanded synthetic resin 24. After passing through the~e alter-
nate layers 23, 24, where the oil is removed Irom the bilge water, the
filtered water will pass through the opposite end deflector plate 22,
which will now function mainly to hold back the bulk of the large particles
within the layer 24, l hereafteI, the filtered water will pass through the
sheet foam layer 21, which will serve to permit r elatively free radial
travel of the filtered water inwardly towards the outlet 1~ and urther
prevent passage of any small particles of the expanded resin.
~; ~he particular oil a~sorbent filter material has an extremely
high absorption capability with respect to oil and can absorb approximately
fifty (50) to seventy (70) times it~ own weight in oil. ~he material is also
non-leaching so that regardless of the passage of time~ the oil will not
return to the water after it has been absorbed by the resin. Also, the
material does not significantly change in size or composition when mixed
~ ~' .' : . , 1
with oil even to the point of saturation, and this material i9 non-toxic so ;~
~ .
that no adverse chemicals are added to 1;he wa~er that is discharged from
the boat. While being oleophilic, the material is hydrophobic due to the
difference in surface tension between oil and water with respect to the
~, pores of the expanded resin.
As one method of constructing the filter material, polyurethane -
is expanded to form a rigid foam according to a conventional process, and ;
.!
thereafter a Pullmarl type o~ cutting millJ which is a knife mill ernploying
three (3) sharp rotating blade8, is uged to chop the rigid polyurethane foa~n
into small granule~ or particlee, which are thereafter passed through screens
to obtain the large particles for the layer 23 and the small particles or the
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layer 24. rrhe actual cutting OI the rigid foam has been found to be critical
with respect to obtaining maximum oil absorption, which is as high as
fifty (50) to seventy (70) times the weigh-t of the resin. ~his has been
found to be true because a grinding or crushing to obtain the particles
will result in closed cell partieles, because grinding will produce suffic~ent
heat to heat seal or self-skin the cellsJ eveII though the cells are reduced
in size, and crushing will merely reduce the size of closed cells without
opening them up~ In contr~st,~ cutting of a closed cell will open up one
wall of the cell for free access oE oil to the interior of the cell, and greatly
10 increase the surface area of the resin exposed to the oil. In Eact, the
: . .
method of forming the particles, for maximum oil absorption, is so critical
that even dull blades oE a Pullman type cutter mill will generate swfficient
heat to close off the cells and significantly reduce the oil absorption capa-
city of the particles. It has been found that the preferred range of particle
size is from one thousand six hulldred ( 1, 600) microns to about ten thousand -
( lû, 000) microns. It has been found that when an expanded rigid synthetic
... .
- resin has been processed according to the prese~t invention through a Pull-
man cutter mill with sharp blades, it will absorb approximately four hundred
percent (400%) more oil than when processed through a grinder to produce
20 the same sized particles. A physical examination of the cross section of
cut material according to the present invention will show tha$ the cut face
exposes an undistor~ed cell interior, ~he resulting particles have a density
of approximately three (3) pounds per cubic foot.
'The particles that have been obtained by the foregoing method
are passed through selected screens to first provide fine or small sized
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particles of two thousand (2, 000) microns or smalleI, and thereafter
produce large size particles falling within the range of five thousand :
(5, 000) microns to two thousand (2, 000) microns.
In ac-tual experimellts, it has,been found that if only the
larger sised particles where used, the oil and water would have a sati~fac-
tory distribution throughout the interior of the filter, but small quantitie~
of oil would pass through the filter long before saturation is reached, so
that discharge of the filtered water would produce a visible sheen on the
surface of open water and not meet the standards discussed above.
Further, actual experiments have shown that if the smaller particle ~ :
. . material was used tthat is having a size of two thousand ( 2, 000) microns
or less) all of the oil would be satisfactorily removed frorn the water ::
initially, but very quickly the water passing through the filter would form : :
channels through the s~laller particles so that there would be very little : ~
. .
contact between the particles and oil resulting in passage uf oil through .
the filter to produce a visible sheen upon the open water where the filtered
water is discnarged long before the filter became saturated; in factJ with ~ .
the smaller particles, the walls of the formed channels would absorb oil
but the interior particles removed from the channels would not be in con-
tact wlth the moving oil and water, so that absorption would be greatly ~ ~ .
, hindered. ~he water axld oil passing through a filter with smaller particles
will almost immediately form channels to result in failure of such a fllter.
According to the present invention, it has been folmd that alternating layers
of large particle filter material (particles falling within the range of approx-
imately twc> thousand ( 2, 000) to f~e ~usand (5, 000) microns) with layers
of ~mall particles of filter material (particles having a si~e of two tho~lsand
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( 2, 000) microns or less) will evenly distribute the flow of liquid through-
out the filter so that uniform saturation of the filter material will pro-
ceed from the inlet to the outlet to provide for maximum oil absorption
and saturation of the filter before the filter will fail and pass oil, and
further the smaller particles will satisfactorily re~ove the oil to meet
the ~ore mentioned requirement~ alld standards. It has been found in
actual tests, that the filter will operate until substantially all of the filtermaterial is saturated with oil, without forming any channels even in the
layers of smaller particle materials, when the smaller and large particle
layers ~re alternated as shown. Preferably, it has been found most desirable
to provide the small particle layers with a length, in the general direction
of fluid flow, that is between two (2) and four (4) times as long as the
length of the large particle layer, and most preferably three (3) times as
~ . ~
long, It is felt that the function of these layers is as follows: the large
particles will, in addition~ to absorbing oil, evenly distribute the liquid
flow throughout the transverse cross section of the filter to prevent sub~
sequent channeling in the small particle layers, and the small particles
: . :
will all be in contact with the moving liquid due to suchdistribution, and
further will be very efficient in removing the oil from the liquid due to their
small particle size so that no oil will be passed beyond the standards men-
tioned above until æaturation is reached. ~he number of alternating layers
., .
!~ ~ will generally determine the life of the filter, and it has been fo~nd that
filters approximately four (4) inches in diameter and approximately twelve (12) `-
inches in le~gth with al$ernating layers of one (1) inch length large particle~
and three (3) inch length small particles will serve to remove oil ~rom the
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S3~ 5~
bilge water and satisfy the above mentioned standards throughout operation
for a normal boating season, without saturation of the filter, Although ~ ~
in Figure 2 the relative size of the alternating layers has not beer~ indi- ::
cated as falling within the above range, the above mentioned ranges are
preferable .
The deflector plate 22 and sheet foam distribution layer 21 :;,
are not esselltial to the prese~t invention, but they do provide further
advantages. Particularly, the deflector plate will initially evenly dis~
tribute the liquid across the transverse cross section at the interior to provide
:- 10 an even distribution of the pre~sure of the liquid at the entrance, and the . . ~ :
plate at the opposite end will as~ure maintenence of this distribution,
Further, the sheet foam layer 21 will provide a spacing or manifold
cavity for the deflector plate and in addition will prevent smaller particles
of the fil1;er material from traveling through the filter outlet 14. It is ~::
thus seen that each of the elements 21 and 22 provide a function at either
: 1
: . the inlet or the outlet, which further facilitates the reversibility of the : ~
' l '
; f ilter . ~ ; ~
~he alternating layers of different size particles further has ~ ;:
an effect in reducing the back pressure on the bilge pump, and it has been
20 found that with respect to conventional bilge pump9, the back pressure is
a critical factor in bilge pump fallure. The physical size of the filter
wlll also depend upon the capacity of the bilge pump, and bilge pumps within
.' the small boat field generally falI within the range of three hundred (300)
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, ~ galloIls per hour to one thousand four hundred (1,400) gallons per hour.
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Since the particles are pr~ferably cut as df~scribed ~ove,
the large particle layer is a mass of particles with cut and rough ~ide
so that when the liquid hits the layer upon ~tart-up, it will cause the
irregular surfaces to lock together while diffusing the force of the fluid
strearn throughout the full area of the filter. The action of the course
particles is very much like the action of trap rock used in road construc-
tion. As in a "french drain", the trap rock is compacted into place thus
providing a solid base for a roadbecl while permitting the free pa~sage of
water; the filtered alternating layer construction operates in much the
10 same way with the larger particles forming a firm ba~e for the smaller
particle layer and distributing the flow evenly to the smaller particle
layer. rrhus, chalmeling and wash out is prevented in the smaller particle
layer.
It has been found that the filter with these alternating layers
will operate until saturation without forming channels, and without the
smaller particles migrating into the larger particles, both of which faults
would occur if the filter were made up of only smaller particles. IJpon
start-up of the bilge pump, the fluid force will hit the filter bed and com-
press the filter material much in the mamler of a coil spring, but the entire
20 mass will be compacted and moved in the direction of fluid flow a small
amount without disturbing the orientation or layering of the particles.
When the ~id pressure is relieved by stopping the bilge pump, the mass
of material will expand back generally into the original position thus freeing
restrictions due to localized conditions and further to prevent the tendency
, to ~orm channels.
'~ Actual tests have shown that if the large particle material
having a size between two thousaxld ~2, 0003 and five thousand ~5, 000~ microns
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is provided throughout the entire filter, no matter how tightly it i~ packed,
it will allow oil to pass entirely through the filter because of the large
percentage of voids between the particles without sufficiently colltacting
the absorbent material with the oil, ~o that con$aminated liquid wil~ be .: ~
dlscharged from the filter in violation of the prececdin~ 8~andards, ætartin~ :
very soon after the installation of a new filter, and long before saturation
is reached. Of course, this problem would be even greater with larger
: ~ ,,; . .:
si2ed particles. ~ -
. On the other hand, if only the finer sized particles were used
.
10 (having a size of two thousand (2, 000) microns or less) throughout the
e~tire filter, the following problems would occur: if the abæorbent material
. were very firmly packed in an effort to prevent channeling, the restriction
to the flow of fluid through the filter would be so great that the resulting .
., back pressure would cause bilge pump failure very quickly If the absorbent. ~.
material of the smaller siged particles were lightly packed throughout the ..
``' en;tire extent of the filter to reduce the back pressure to an acceptable levelJ ..
~. .
~' chaImeling would occur where the liquid traveling through the filter would
.,, form easily recognized .visible channels through the filter 80 that there
,. would be in9ufficient contact between the oil and filter material ~o that very
20 quickly the filter would paæs contaminated liquid in violation of the above
:.' standards,
~ In Figure 3, there iæ shown a permanent installation for the ~.
:, filter, which ætructure may be used in place of the structure shown in ~ :
;, Figure 2, so that either the filter of Figure 2 or Figure 3 may be used in
the system of Figure l. In Figure 3, a dieposable cartridge 25 ~nay be
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usedth~t is identical to all of the ~tructures shown in ~i~igure 2, e~cept that it
may or may not include the nipples described with respect to Figure 2,
'rhus with respect to the disposable cartridge 25, identical numerals
have been provided for structure that i~ identical to that described with
respect to Figure 2, and further description theref~>re of th~se elernen~8
will be unnecessary.
l'he disposable cartridge 25 of Figure 3 ispreferabll5~ con-
tained within a permanent cup-shaped member 26 that may be constructed
of metal. A coil spring 27 is provided between the lower end of the car-
10 tridge 25 and the cup-sh~ped housing 26, to provide a spacing between these ~ . ~
two elements and permit flow of fluid into or out of the opening 33 of the ~ ~;
cartridge 25, The other end of the cartridge 25 is held in place by means
.~ of a cap 28 that is ex1;ernally threaded and secured to the open end of the
~, cup-shaped housing 26 by internal threads on the housing 26. 'rhe cap 28 .
.ii may be rigid plastic or metal, and is provided with a iluid passage 29 that
opens to the side to provide either the inlet 13 or the outlet 14 of the filter
and at its other end opens to the interior of the filter housing in alignment
with the opening 30 of the cartridge 25. ~he cap 28 is further provided with
. ~ a fluid passage 31 that opens on the opposite side of the cap 28 to provide
.' 20 either the inlet or outlet and at its other end opens tothe amlular passage
between the cartridge 25 and substalltially larger housing 26, ~his thus :
formed annular passage and the end spaee provided by the spring 27 form
a chamber 32 to provide liquid .cs;mmumieation between the port 31 and the ~ .
opening 33 exteriorly of the cartridge 25. ~he cartridge 25 is held in this
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centrallocation to assure the formation of the chamber 32, by means of
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a recess 34 in the lower end of the cap 2~, into which the upper end of
the cartridge 25 i9 resiliently held to form a seal between the cartridge
25 and thc end cap 28 while at the ~ame tirne providing communication ~:
between the passage 29 and opening 30. ~hus, it is seen that i:E the pas~-
age 29 were used as the inlet, fluid would pass through the opening 30,
through the interior of the car$ridge 25, through the opening 33, through
the spring 27, through the chamber 3~ and through the passage 31. The
outlet end of each of the passages 29 and 31 i9 provided with either inter- ;
~al, as shown, or e~ternal, not shown, threads for securing pipes or
the like, or ridges may be provided for securing r esilient hoses with
hose clamps.
When it is desired to change the filter at the beginning of
a season, or when saturation is reached as shown by the indicator 13,
the housing 26 is easily unscrewed from the cap 28, so that the cartridge ~:
25 may be thrown away and replaced by a new cartridge 25 wlthout dis-
connectmg any flow lines. ~.
l~he visual indlcator as shown in Figure 4 may be of many :
different types of construction, but IS preferably ormed by a one (1)
piece molded synthetic resin generally cup-shaped member 43 having
an inlet nlpple 1~, and a generally cup-shaped one (1) piece molded syn-
i
thetic resin member 44 that has an outer peripheral and radial flange 45,
with an indicator material 47 clamped therebetween around the joining
periphery 46 of the members 43 and 44. ~he member 44 is constructed
of a transparent material that will permit viewing of the indicator material ~ :
47 from the exterior (to the right oi Figure 4) of the boat hull 1 substan-
tially above the water line as shown in ~ re 1. l~he periphery 46 may
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~5~5~1
be bonded by any conventional manner to provide a fluid tight closure and
to securely .hold the material 47 around its periphery, ~he material 47
may be a white cotton fabric that will quickly pick-up and be discolored
or colored by any oil passing through the indicator 15 to provide a vi~ua~
indication through the clear member 44 to the exterior of the boat hull 1 . .
that the filter 12 i9 passing oil.
'The relief valve of Figure 5 has been fo~md to be extremely
important with respect to preventing early bilge pump failure. While the
relief valve may take on many form~ and may be cho~en from a ~tandard ; ~ ~ .
10 line of.similarly operated valve~, the preferred form of the valve i9 ghown
in Figure 5, wherein a one (1) piece synthetic resin member is molded with :
opposed connectors 35 and 36J which may have means on them for securing
the iluid lines, for example, e~ternal ridges to engage resilient tubes that
are provided with hose clamps. An upstanding annular wall 37 forms a
valve chamber having at orle end the opening 38 formed by a peripheral
`l shoulder that supports a perforated retention plate 39, which plate in turn
supports a iloat valve 40 that may be a standard ping pong ball. The upper
end of the valve chamber is closed by means o~ a cap 41, which may be
constructed in one (1) piece of a synthetic resin and bonded to the annular
member 37. ~he cap 41 is provided with a circular opening 42 that may ~
be formed with any type OI sealing lip to cooperate with the float valve ~0
In operation, the connectors 35 and 36 may function as either the inlet
or outlet, so that when installed in the system of Figure 1, the valve 11
will ~unction to eliminate any back pressure on the bilge pump 8 during
start-up, because initially the bilge pump 8 will be purging itself and the :
connecting lines of air, which air will freely pass through the valve 11
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without passing through the considerable restriction of the filter 12 ~o that
the pump 8 may start-up and reach its rated speed and start pumping liquid
before there is any back pressure produced on the pump. Once liquid i~
pumped to the valve 11, the liquid will enter the valve chamber and force
the float valve member 40 upwardly to seal the opening 42, so that thereafter
all of the liquid pumped by the pump 8 must pass sarially thr~ugh the filter 12,
indicator 15, and outlet 18 to be discharged to the open water surrounding the
boat. Upon ~hutdown, leakage will occur and the back pressure will be relieved -
through the valve 11, filter 12, and the pump 8, so that again upon start-up
10 there will be no back pres6ure on the pump 8. In actual tests, it has been
found that the commercially available bilge pumps are extremely sensitive
to back pressure, and that the back pressure on these pumps is critical with
respect to their early failure.
While the layermg construction of the filter is quite important~
with respect to relieving back pressure, it has been found that the relief
valve is even more Important ~ ith respect to ellminating back pressure during ~`
start-up. In actual tests without the valve 11, it was found that the filter
and any trapped liquid would many tirnes provide su~icient back pressure to
.
the pump 8 so that the pump would not start-up and the motor qperatlng the
20 pump would quickly burn out. It is known that motors draw the most current
when they are startmg-up and that pumps require conslderable power during
start-up due to the inertia of their moveable parts, so that if back pressure
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were added to the pump, the total result is many times enough to prevent
start-up of the pump and burn out the motor,
Smce operation~ of ~the individual parts ha~ been described along
~ ~ with their construction, a separate operation will not be set ~orth in detail,
`.
~5315~
While the preferred embodiment relates to the sy~tem for
removing bilge water from a boat and preventing the discharge of oil
to meet the above mentioned standards, the illustrated system 9
may also be provided for other installations, for e~ample within a swim- .
ming pool filtration system to remove .sunta~ lotion oil ancl body olls from
the water. If these oils were not removed, they tend to suppc>rt the growth
of algae that will greatly discolor the water and require the additiorl of
large quantities of chlorine and other substances that are generally urlde-
sirable, Further, the system could be used in in~ustrial applications9 for
10 example where cooling water may pick up l~bricating oil fro~n: ~acl~ r~.
l he~e further uses are according to the broader aspect~ of the present
invention.
`~ Further, the system can be expanded to a si~e large enough ~ ~
to service a marina and by ha~ring the boats bypass their filters and pump ~: :
directly into a header system and then into a large dock side filter, and
': discharge the clean water back into the main body of water, -.
.~ While a preferred e:mbodiment of the present invention has
been shown and described in detail for purposes OI illustration and for `;
the advantages of the specific details, further embodiments, modifications
: 20 and variations are contemplated within the spirit and scope of the present .::
invention, all as defined by the following claims~
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