Mutli-stage grease trap filter and skimmer

An apparatus for removing grease from a compartmental grease trap that has water provided therewithin so that grease forms a layer atop the water in the trap. The apparatus has a mounting portion that is securable to the grease trap and a housing portion pivotally connected to the mounting portion. A filter media is then secured by the housing portion. The housing portion is preferably constructed from a framing structure and an inner structure. The framing structure has two sets of opposed sidewalls and a perforated or mesh bottom sheet that allows water to pass therethrough. The inner structure is separably secured to the framing structure, such as by pivotal connection and the filter media is preferably held between the inner structure and the framing structure. The inner structure is capable of being locked into position with respect to the framing structure by a locking device. The housing portion may be caused to pivot relative to the mounting portion such as by a linkage, preferably a solid rod, connected at one end to the housing portion and accessible at an opposite end by an operator.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates generally to methods and apparatus for removing 
grease from grease traps and more particularly to a filter and skimmer for 
use in compartmental grease traps. 
2. Description of the Prior Art 
For any industry in which grease and/or oils are used, those oils and 
grease must be discarded. Typically, this is done through the use of 
grease traps. A popular type of grease trap is the "Weir Type" or 
compartment grease trap. Weir Type grease traps have compartments where 
the grease is held. The grease trap compartments are bordered by vertical 
sidewalls. These compartment grease traps are typically in ground and are 
located within close proximity of the grease and oil source. Water is 
present in the grease trap and grease and oil are entered into tile 
influent water in the grease trap. When such grease traps are used, the 
grease and oil (which are generally referred to collectively as "grease") 
float to the top of the water in the grease trap and must be removed from 
the influent water before being discharged into the waste water stream and 
ultimately to the waste water treatment facility. 
Once the grease is entered into the grease trap, the grease separates from 
the water and floats atop the water. The floating grease must then be 
removed from the grease trap. Floating grease has been removed from the 
grease traps in the prior art by various techniques. Perhaps the most 
commonly utilized technique is to scoop out the floating grease through 
the use of a bucket or some other container. This technique offers the 
disadvantage of being time intensive and tends to be "messy" in that it 
usually subjects the operator to contact with the grease. Also, because 
the bucket entered the grease trap from above the grease, the bucket could 
temporarily mix the grease and cause some of the grease to temporarily 
move lower in the grease trap water so as to avoid removal. Further, the 
scoop out technique also withdraws a substantial amount of the water from 
the grease trap along with the grease. 
Another commonly used technique for removing grease from a grease trap is 
the siphoning of the grease through the use of a vacuum. Vacuums have 
motors and other moving parts which are prone to failure. Furthermore, 
vacuums also tend to withdraw a substantial amount of water along with the 
grease when utilized. 
A more recent technique has been bioremediation. Bioremediation involves 
the use of organisms which are introduced into the grease trap to digest 
the grease. Bioremediation requires additional room for off load tanks for 
the microorganisms to process the grease (known as residence time). 
Additional space is often unavailable, and in any event, the use of 
additional space for grease processing is generally undesirable. 
Thus, a grease removal system is needed that does not require additional 
space, may be utilized with the existing grease trap structure, is not 
prone to breakdown, is not time intensive and does not remove water from 
the grease trap along with the grease. 
SUMMARY OF THE INVENTION 
An apparatus is provided for removing grease from a grease trap. The grease 
trap contemplated for use with the present invention has at least one 
compartment that is bordered and defined by two sets of opposed, vertical 
sidewalls and a bottom wall. A fluid, preferably water, is then provided 
within the grease trap compartment and grease is also entered into the 
grease trap compartment such that the grease forms a layer generally atop 
the fluid through separation. 
The apparatus removes the layer of grease from the grease trap by filtering 
and skimming the layer of grease. The apparatus has a mounting portion 
that is securable to the grease trap by being secured to at least one of 
the vertical side walls of the grease trap compartment. The mounting 
structure is preferably an elongated mounting plate that is matable with 
one of the grease trap compartment vertical side walls. 
The elongated mounting plate is preferably secured to the vertical side 
wall by having one or more openings provided through the mounting plate 
that are each alignable with a respective opening through the vertical 
side wall, and a screw, bolt, rivet, pin or similar securing means is then 
disposed through each pair of aligned openings. 
Alternatively, the elongated mounting plate may be secured to the vertical 
side wall by means of the mounting plate having an overhang portion 
provided thereon, in which the overhang portion is placed upon a vertical 
side wall. 
A housing portion is then pivotally connected to the mounting portion. The 
housing portion is preferably pivotally connected to the mounting portion 
by means of one or more, and preferably two, pins being connected to the 
mounting portion and the pins being disposed through one or more, and 
preferably two, apertures of the housing portion. The pins may be welded 
or otherwise affixed to the mounting portion or may instead be disposed 
through openings in the mounting portion. The apertures of the housing 
portion are preferably arcuate in shape. 
Alternatively, the pins may be connected to the housing portion and 
disposed through apertures in the mounting portion. Moreover, the housing 
portion may be pivotally connected to the mounting portion by means of a 
hinge connected to the housing portion and the mounting portion. 
A filter media is then secured to the housing portion. The housing portion 
is preferably constructed from a framing structure and an inner structure. 
The framing structure has two sets of opposed sidewalls and a perforated 
or mesh bottom sheet that allows water to pass therethrough. The inner 
structure is connected to the framing structure. Preferably, the inner 
structure is separably connected to the framing structure. The preferred 
means for separably connecting the inner structure to the framing 
structure is by pivotally securing the inner structure to the framing 
structure. In this way, the inner structure may be pivoted so as to be 
proximate the perforated mesh bottom sheet of the framing structure or may 
be pivoted so as to substantially separate from the mesh bottom sheet of 
the framing structure. The filter media is preferably secured to the 
housing portion by being provided between the framing structure and the 
inner structure. Thus, when the inner structure is pivoted away from the 
framing structure, the filter media may be inserted upon the framing 
structure. Then, the inner structure if pivoted back towards the bottom 
sheet of the framing structure so as to contain the filter media 
therebetween. When the inner structure is pivoted towards the bottom sheet 
of the framing structure, the inner structure is capable of being locked 
into position with respect to the framing structure by means of a locking 
device. The locking device preferably includes a spring biased detent. 
The framing structure and the inner structure are preferably fabricated of 
stainless steel, but may be made of any suitable material such as coated 
steel, plastic, aluminum and aluminum alloys. The filter media is 
preferably made of an open celled material. Polyester and polypropylene 
are preferred, but any suitable material that will allow water to pass 
through but will not allow the grease to pass through may be used. 
The apparatus is also equipped with a means for causing the housing portion 
to pivot relative to the mounting portion. The preferred means for 
pivoting the housing portion is an elongated linkage connected at one end 
to the housing portion and accessible at an opposite end by an operator. 
When pulled and released, the linkage will cause the housing portion to 
pivot relative to the mounting portion. The linkage is preferably a rigid 
member such as a rod, but may also be a flexible linkage such as a chain, 
or may be any other convenient linkage that can withstand the environment 
of the grease trap. 
Other objects and advantages of the invention will become apparent from a 
description of certain present preferred embodiments thereof shown in the 
drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring first to FIG. 1, an exploded, perspective view of a preferred 
filter and skimming apparatus 10 is shown for removing grease from grease 
traps. The apparatus 10 has a mounting assembly 12 that is mounted to the 
grease trap (not shown in FIG. 1), preferably by being secured to a 
vertically oriented sidewall of the grease trap structure as will be 
described in greater detail below. 
Referring next to FIG. 2, a prior art compartmental grease trap structure 
34 is shown in dotted line having a mounting assembly 12 secured thereto. 
The mounting assembly is preferably made of an elongated mounting plate 38 
that is matable with the grease trap compartment vertical side wall 36. 
The elongated mounting plate 38 is preferably secured to the vertical side 
wall 36 by having one or more openings 40 provided through the mounting 
plate 38 that are each alignable with a respective opening through the 
grease trap vertical side wall 36, and a screw, bolt, rivet, pin or 
similar securing means 44 is then disposed through each pair of aligned 
openings in the mounting assembly 12 and grease trap side wall 36. 
Alternatively, the elongated mounting plate 38 may be secured to the 
vertical side wall 36 by other suitable means, such as through the use of 
an adhesive substance, such as an epoxy, glue or resin, provided between 
the mounting plate 38 and the vertical side wall 36. Also, the elongated 
mounting plate may be secured to the vertical side wall by means of a 
clamp (not shown), preferably a spring-biased clamp. In addition, the 
elongated mounting plate 38 may be secured to the vertical side wall 36 by 
means of the mounting plate 38 having a channel or overhang portion 
provided thereon, in which the mounting plate channel or overhang portion 
engages the vertical side wall 36. 
Referring to FIGS. 1, 3 and 4, the filter apparatus 10 preferably also has 
a housing 14 that is connected to the mounting assembly 12. The filter 
housing 14 is connected to the mounting assembly 12 such that the filter 
housing 14 may pivot relative to the mounting assembly 12. Any means for 
pivotally connecting the filter housing 14 to the mounting assembly 12 may 
be used, such as a hinge. However, the preferred means for pivotally 
connecting the filter housing 14 to the mounting assembly 12 is through 
two pins 26 that are connected to the mounting assembly 12 and are then 
disposed through apertures 28 in the filter housing 14. In this way, the 
pins 26 may rotate within the apertures 28 and/or the apertures 28 may 
rotate about the pins 26. It is preferred that the apertures 28 are 
arcuate so that the filter housing 14 may translate relative to the pins 
26 as well as rotate about pins 26. 
Although two apertures 28 are preferred for the pivotal connection of the 
filter housing 14 and the mounting assembly 12, a single aperture 28 may 
also be used. Similarly, although two pins 26 are preferred, a single pin 
26 may connect to the filter main body and cooperate with the apertures 
28. Pins 26 may be connected to the filter housing 14 by being welded 
thereto or by being disposed through openings of the filter housing 14. 
A preferred embodiment of the filter housing 14 is described herein. 
However, it is distinctly understood that any filter housing structure may 
be utilized which may hold a filter media, allow water to pass 
therethrough and that can pivot relative to a mounting. 
The preferred filter housing 14 has a framing structure 16 having two sets 
of opposed sidewalls 17. Along the bottom of the framing structure 16 is 
placed a porous open mesh or perforated bottom sheet 18 that provides 
structural support to the framing structure 16, yet allows water to easily 
pass through the openings or perforations 19. The bottom sheet 18 is 
preferably affixed into position upon the framing structure 16, such as by 
being welded thereto. One or more supporting members 24 may be provided on 
the framing structure 16 to assist in supporting the bottom sheet 18 and 
providing additional locations to affix the bottom sheet to the framing 
structure 16. 
An inner structure 20 is then secured to the framing structure 16. The 
inner structure 20 helps to hold the filter media 22. The filter media 22 
may be held by being secured directly to the framing structure 16, by 
being secured directly to the inner structure 20, or preferably by being 
secured between the inner structure 20 and the framing structure 16 of the 
filter housing 14. 
The inner structure 20 is preferably separable from the framing structure 
16. The preferred means for making the inner structure 20 separable from 
the framing structure 16 is by pivotally securing the inner structure 20 
to the framing structure 16. The inner structure 20 and the framing 
structure 16 may be pivotable with respect to one another by any 
convenient means. However, the preferred means for pivotally connecting 
the inner structure 20 to the framing structure 16 is through two pins 41 
that are connected to the inner structure 20 and are then disposed through 
respective apertures 42 through the framing structure 16. In this way, the 
pins 41 may rotate within the apertures 42 and/or the apertures 42 may 
rotate about the pins 41. Although two pins 41 and two apertures 42 are 
preferred, it is understood that a single pin may be used or a single 
aperture. In fact, any convenient means may be used for pivoting the inner 
structure 20 and the framing structure 16 relative to one another may be 
employed. 
The position of the inner structure 20 is preferably fixed relative to the 
framing structure 16 by means of a locking device 30. The locking device 
preferably includes a spring-biased detent 29. Detent 29 is normally 
spring-biased outward so as to obstruct the path of inner structure 20 
from pivoting away from the perforated bottom sheet 18. When a sufficient 
force is applied to the detent 29, the bias of the spring is overcome and 
the detent is moved so as not to obstruct the path of the inner structure 
20, thus enabling inner structure 20 to pivot away from the perforated 
bottom sheet 18. It is understood, however, that any means for locking or 
securing the position of inner structure 20 relative to the framing 
structure 16 may be utilized. 
Thus, the filter media 22 is preferably contained between the inner 
structure 20 and the framing structure 16 of the filter housing 14. When 
the inner structure 20 is pivoted towards the perforated bottom sheet 18 
and is secured into position by locking device 30, the relative positions 
of the inner structure 20 and the framing structure 16 are fixed, and when 
a filter media 22 is placed between the inner structure 20 and the framing 
structure 16 the position of the filter media 22 is also fixed within the 
filter housing 14. 
With the inner structure 20 thus fixed into position relative to the 
framing structure 16 by the locking device 30, the filter housing 14 is 
said to be in a "closed" position as shown in FIG. 3. Inner structure 20 
is further preferably provided with support members 25 which assist in 
retaining the filter media 22 between the inner structure and the framing 
structure 16 while allowing water to pass through inner structure 20. 
Although two inner structure support members 25 are shown in an "X" 
orientation, any number or configuration of support members may be 
utilized so long as water is allowed to pass therethrough. 
When the locking device 30 is disengaged, e.g., such as by applying a force 
to the spring-biased detent 29 to overcome the spring bias, the inner 
structure 20 may be pivoted away from perforated bottom sheet 18 as shown 
in FIG. 4. With the filter housing 14 thus being in an "open" position, 
the filter media 22 may be removed, replaced, inserted, or reinserted. 
Once the filter media 22 is replaced between the framing structure 16 and 
the inner structure 20, the inner structure 20 may be pivoted toward the 
bottom sheet 18 and locked into position by locking device 30 so that the 
device 10 is ready for operation. 
Referring next to FIGS. 1, 5 and 6, when assembled, the filter housing 14 
which houses the filter media 22 is pivotable relative to the mounting 
assembly 12. Since the mounting assembly 12 is secured to the grease trap 
vertical compartment wall 36, the filter housing 14 is thus movable 
relative to the grease trap 34. 
A portion of the filter housing 14 opposite to the portion of the filter 
housing 14 that is pivotally connected to the mounting assembly 12 has an 
actuation member 32 attached to it. The actuation member 32 is preferably 
an elongated rod that is attached to the filter housing 14, such as 
through the use of a bolt 46 having a nut 47, wherein the bolt 46 is 
disposed through an opening 33 in the actuation member 32 (shown best in 
FIG. 7) and through one or more holes 31 in the framing structure 16. In 
this way, the actuation member 32 is pivotably connected to filter housing 
14. It is understood, however, that any suitable means of connecting the 
actuation member 32 to the filter housing 14 may be used. When the 
actuation rod 32 is pulled and released by an operator, the filter housing 
14 which holds the filter media 22 is caused to pivot relative to the 
grease trap compartment 34 providing the filter housing 14 with a skimming 
motion. Although the actuation member 32 is preferably a rigid member, 
such as a rod, the actuation member 32 may be any suitable linkage which 
can transmit the force needed to operate the pivoting of the grease trap 
compartment 34 and withstand the environment of the grease trap. For 
example, a flexible linkage, such as a chain, could be utilized. 
Furthermore, it is preferred that the hole 31 in the framing structure 16 
be provided through a portion 21 of the framing structure 16 which extends 
outward from the framing structure wall 17. However, the hole 31 may 
instead be provided directly through the framing structure wall 
The filter media 22 is preferably constructed of one or more open celled 
materials. Suitable materials for use as the filter media 22 include 
polyester, polypropylene or any hydrophilic or open celled hydrophilic 
material. The filter and skimming apparatus 10, except for the filter 
media 22, is preferably fabricated from 304 stainless steel. However, 
other materials may be used such as plastic, aluminum, coated steel, 
alloys and any other material that is capable of resisting oxidation 
and/or chemical breakdown from the environment of the grease trap 34 and 
that is also capable of withstanding the high temperatures present in the 
grease trap 34 environment. 
Preferably, the length and width dimensions of the housing 14 of the filter 
and skimming apparatus 10 are slightly less than the length and width 
dimensions of the grease trap compartment 34 in which the filter and 
skimming apparatus 10 is employed. The depth dimension of the housing 14 
of the filter and skimming apparatus 10 is roughly equivalent to the 
thickness of the particular filter media 22 employed by the filter and 
skimming apparatus 10. The thickness of the filter media 22 is in turn 
dependent upon the amount and type of grease that is required to be 
extracted from the grease trap 34. 
In operation, when the filter housing 14 is initially secured to the 
mounting assembly 12 and no external force is applied to the filter device 
10, the filter housing 14 hangs downward so as to be essentially parallel 
to the vertical sidewall 36 of the grease trap compartment 34, which 
position is depicted in FIG. 6. Then, when the filter housing 14 is caused 
to rotate about the mounting assembly 12, such as by an operator pulling 
on the actuation linkage 32, the filter housing 14 swings upward from 
below the layer of grease 46. The filter media 22, which is held by the 
filter housing 14, is thus able to skim the grease out from the water. The 
filter housing 14 may be pivoted at least to a position essentially 
perpendicular to the vertical side wall 36 of the grease trap compartment 
34, which position is depicted in FIG. 5. The water passes through the 
filter media 22 and through the mesh openings 19 in the bottom wall 18 of 
the framing structure 16. 
Despite the housing 14 of the filter device 10 being sized approximately 
the same as the compartment of the grease trap 34, the filter housing 14 
is able to avoid being stuck against the grease trap compartment walls 36 
during the pivoting of the filter housing 14 due to the arcuate apertures 
28 of the pivotal connection 24. The pins 26 which are disposed through 
apertures 28 are able to translate along the apertures 28. 
While certain present preferred embodiments have been shown and described, 
it is distinctly understood that the invention is not limited thereto but 
may be otherwise embodied within the scope of the following claims.