Ventilated litter box

An animal litter box includes a housing and a tray for containing a bed of litter material. The tray is provided with a porous bottom spaced from the bottom of the housing to define an air space. An exhaust fan is connected to a port through the wall of the housing to draw air downwardly through the litter bed to dry the litter and exhaust the litter odors. The exhaused air may be passed through the odor absorbing filter assembly to deodorize the air before venting the air.

FIELD OF THE INVENTION 
The present invention is directed to an animal litter box including a 
device for exhausting odors and drying the litter. More particularly, the 
invention is directed to a ventilated litter box having an odor absorbing 
material to remove odors from air drawn downwardly through the litter bed 
before exhausting the air to a remote location. 
BACKGROUND OF THE INVENTION 
Many domestic pets and particularly cats are often kept indoors and require 
that a suitable litter box or container be available for use by the 
animal. Animal litter products are generally an absorbent material such as 
granulated clay particles or vegetable material. Those materials have the 
advantage of being absorbent and a natural attractant to the animal. 
Litter boxes, however, have the distinct disadvantage of requiring regular 
cleaning or changing of the litter material. Litter box also usually 
result in the emanation of malodors, typically referred to as litter box 
odors. To prevent odors from emanating throughout the pet owner's house, 
it is usually necessary to change the litter daily. The burden and expense 
of daily changing of litter is a major factor in the pet owners failure to 
routinely change the litter. 
In order to minimize the burden and unpleasantness of changing a litter box 
numerous devices have been developed. These devices include, for example, 
containers to receive the spent litter and devices to replace the spent 
litter with fresh litter. Other devices include systems to vent animal 
waste odors away from the immediate area and systems to mask the odor 
being Emitted from the litter box. One example of such a device is 
disclosed in U.S. Pat. No. 3,428,026 where a litter box is provided with 
an enclosure to contain the waste odors. A solid cake of deodorant 
material is contained within the enclosure to mask the odors by 
continuously releasing the deodorant. 
Another example of a device intended to control animal waste odors is 
disclosed in U.S. Pat. No. 3,793,989. In this device an enclosure is 
provided to contain the animal litter and the litter box. An electric 
powered fan is included within the confines of the enclosure to circulate 
and distribute a deodorizer from a solid, semisolid or liquid deodorizer. 
The above-noted devices attempt to control odors primarily by containment 
and masking of the odors. These devices are deficient in that they do not 
remove the odors from the air or remove the odor-causing waste material 
from the litter. 
Other devices have been developed to attempt to remove pet odors from the 
air such as disclosed in U.S. Pat. No. 3,487,814. This device includes a 
housing to enclose a litter box. A fan is mounted in the upper portion of 
the housing to draw air and odors from the litter box through a screen 
which is impregnated with an odor absorbing material. Another example of 
an odor elimination device is disclosed in U.S. Pat. No. 4,095,559. The 
device includes an enclosure which fits on top of a litter box to form a 
partial cover. The enclosure defines a partial top cover and includes a 
skirt portion having an air channel. An electric fan is connected to the 
top cover to draw air from the litter box and vents the air to the 
outside. 
The previous litter devices used heretofore do not adequately remove odors 
from the litter box or eliminate the release of odors to the room. The 
previous devices further do not provide a litter box which is able to 
effectively dry the litter while preventing the release of odors to the 
room. There is, therefore, a need for a litter box which is simple and 
inexpensive to manufacture and is able to effectively remove and control 
litter box odors. 
SUMMARY OF THE INVENTION 
The present invention is directed to an animal litter box having a device 
to exhaust the litter odors to a remote location. The litter box is 
constructed from a tray or housing having a bottom portion and upwardly 
extending walls which terminate at an outwardly extending flange. A porous 
support member to support the litter material is spaced above the bottom 
portion of the housing to define an air space below the litter bed. A fan 
is connected to the housing through a coupling to draw air from the air 
space. The fan draws air downwardly through the litter bed to dry the 
litter and prevent the escape of odors. The air may be exhausted to a 
remote location. 
In a further embodiment of the invention, the air exhausted from the litter 
box is passed through an odor absorbing filter assembly to deodorize the 
air by absorbing the waste odors on the filter material. The deodorized 
air may be vented to a remote location, vented to the same environment of 
the litter box or returned to the upper portion of the litter bed. 
The litter box, in an alternative embodiment, includes a housing having a 
bed of odor absorbing filter material spaced above a bottom portion of the 
housing. A bed of litter is spaced above the filter material. The housing 
is provided with a fan to draw air downwardly through the litter bed and 
filter bed to dry the litter and odorize the air. In embodiments of the 
invention, the litter box is provided with a top cover supported on the 
housing and having an opening for ingress and egress by the animal. The 
deodorized air drawn from the litter may be vented back to the top cover.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention is directed to an animal litter box having a fan or 
blower to draw air through the litter material. The litter box is provided 
with a foraminous bottom to support the litter material. The blower is 
connected to the litter box to withdraw the odors from the litter and dry 
the litter by the air passing downward through the litter bed. 
A preferred embodiment of the invention is illustrated in FIG. 1. The 
litter box includes an open-top bottom tray lo having a bottom panel 12 
and upwardly extending sloping side walls 14. An outwardly extending 
flange portion 16 depends from the upper edge of the walls 14 and extends 
around the perimeter of the tray. An inner tray 18 is provided with 
sloping walls to allow nesting within the bottom tray 10. The inner tray 
18 includes a porous bottom portion 20 and upwardly sloping walls 22. A 
depending skirt portion 24 extends outwardly from the upper edge of the 
wall 22 around the perimeter which is spaced with a thick rubber gasket 
and rests on the flange portion 16 of the bottom tray 10. The inner tray 
18 is a modified duplicate of the bottom tray 10 equally dimensioned such 
that it can be nested within the bottom tray. The side walls 22 and bottom 
portion 20 of the inner tray 18 are preferably spaced from the walls 14 
and bottom panel 12 of the bottom tray 10. In a preferred embodiment, the 
bottom portion is porous substantially throughout the entire bottom 
surface area. 
The porous bottom portion 20 of the inner tray may be a perforated 
plate-like bottom. Alternatively, the bottom of the inner tray may have a 
lattice or screen-like structure. A porous mat 26 may be placed over the 
porous bottom portion to support a litter material. Alternatively a porous 
foam filter-like mat may be placed over the bottom portion 20. The mat may 
be, for example, a polyester-polyurethane filter material. The litter 
material 28 is received on the mat 26 and retained in the inner tray for 
use by the animal. In the embodiment shown in FIG. 1, the litter box is 
provided with a top removable enclosure 30 having an entrance port 32 to 
allow access by the animal to the litter material. The entrance port 32 
may be provided with a fringe curtain 34 to obstruct the view of the 
litter material and to contain waste odors. Also the cat might like 
privacy when it visits the box. 
The skirt portion 24 of the inner tray is preferably provided with a 
sealing member in the form of a thick rubber gasket to form an effective 
seal between the skirt portion 24 and the flange portion 16 of the bottom 
tray 10. In a preferred embodiment of the invention the rubber gasket 
material is adhesively attached to skirt portion 24 on the underside 
surface opposing the upper face of flange portion 16 of the bottom tray 
10. Alternatively, the rubber gasket material may be adhesively attached 
to the upper surface of the flange 16. The side wall 14 of the bottom tray 
10 is provided with a connection to receive a flexible hose member 36. In 
the embodiment shown in FIG. 1, the hose member 36 is connected to the 
tray and extends to an exhaust port in a wall to vent the air and odors to 
an outside location. As shown, the air is exhausted through a wall, 
although it may also be vented through a window or to a remote location. A 
fan 38 is attached to the end of the flexible hose member 36 to draw air 
through the hose from the litter box. As shown in FIG. 1, the fan is 
attached to the end of the hose at a remote location from the litter box 
so as not to frighten the animal and deter use of the litter box. In an 
alternative embodiment of the invention, the fan 38 may be mounted on the 
wall 14 of the bottom tray 10. The hose 36 is preferably connected to the 
fan to exhaust the air and odors to another location. In this embodiment, 
the fan is preferably sufficiently small and quiet so as not to act as a 
deterrent to use of the litter by the animal. 
The spacing between the inner tray 20 and the bottom tray 10 defines an air 
space of reduced pressure when connected to the fan 38 and the fan is 
operated. The fan 38 produces a reduced pressure in the bottom tray 10 
below the inner tray 20 supporting the litter. Air is drawn downwardly 
through the entire bed of litter to dry the litter and exhaust the waste 
odors to the external environment and prevent the release of the odors to 
the room. Preferably the bottom portion of the inner tray is porous to the 
flow of air throughout the entire surface to allow the air to pass through 
the entire bed of litter and dry the litter. 
The fan 38 may be continuously operated and provided with an on-off switch. 
In one embodiment the fan may be connected to a control timer to actuate 
the fan at predetermined and periodic intervals. In a further embodiment 
of the invention the inner tray 20 may include a weight sensor 40 
connected to a switching device to actuate the fan. In this embodiment the 
fan may be actuated by the sensor detecting the presence of an animal in 
the litter box. The sensor may be, for example, a weight actuated sensor 
or an optical sensor. The weight of the animal may trip a weight sensor 
and actuate the fan for a predetermined period of time to dry the litter 
and remove the odors. The litter box may further include a moisture sensor 
41 to operate the fan until the moisture level in the litter box is 
reduced to a predetermined level. 
In a further embodiment of the invention as shown in FIG. 2, the litter box 
includes a bottom tray 42 having a bottom panel 44 and upright side walls 
46. A depending flange 48 extends outwardly from the upper edges of the 
sloping side walls 46 around the perimeter thereof. An inner tray 49 is 
provided with a porous bottom panel 50 and non-porous and upstanding 
sloping walls 52. The inner tray 49 is dimensioned the same a the bottom 
tray 42 to allow nesting within bottom tray as shown in FIG. 2. A 
depending skirt or flange portion 54 extends from the upper edges of the 
sloping walls 52 of the inner tray. A rubber gasket material 95 is 
provided on the underside of the flange 54 of inner tray 49. The inner 
tray is nested in the bottom tray with the skirt portion 54 supported on 
the gasket 95 on the flange 48 such that the sloping walls and bottom 
panel of the inner tray are spaced from the walls and bottom panel of the 
bottom tray. 
A hose connection is provided and extends from a side wall of the bottom 
tray. A flexible air hose is attached to the connection and extends to a 
filter assembly 60. The filter assembly includes a housing 62 having 
upstanding sloping walls 64. The upper edges of the walls 64 are provided 
with a depending flange 66 extending outwardly from the wall to form a 
substantially horizontal support surface. A hose connection 68 extends 
through the wall 64 to receive the hose from the little box. An inner tray 
70 equally dimensioned as housing 62 is nested within the housing 62 as 
shown in FIG. 2. The inner tray also includes side sloping walls 72 to 
allow nesting of trays, a bottom wall 74 and top cover 76. In a preferred 
embodiment, the side sloping walls 72 are not perforated and only the 
bottom wall 74 is perforated to allow the free flow of air upwardly 
through the filter assembly. An odor absorbing material 77 is provided in 
the inner tray for contact with the air from the litter box. A fan 78 is 
mounted on the cover 76 and is in communication with a port (not shown) to 
draw air outwardly from the filter assembly 60. In operation of the device 
shown in FIG. 2, the fan 78 causes air to be drawn downwardly through the 
litter bed and through the porous bottom panel of the inner tray to dry 
the bed of litter and draw the odors away from the litter. The odorous air 
is then drawn through the hose and passed through the filter assembly and 
the odor absorbing material. The fan 78 may discharge the filtered and 
deodorized air back to the room or to a remote location as desired. 
The odor absorbing material contained in the filter assembly may be a 
suitable absorbent or adsorbent as well known by those skilled in the art. 
In the preferred embodiment, the odor-absorbing filter material is an 
activated charcoal although other materials may be used. Exemplary filter 
materials may include zeolites, alumina, silica, silica gel or 
organomodified silicas which are capable of absorbing odorous substances 
from the air. The filter material may also include a deodorizing agent or 
an odor masking agent. The deodorizer or the odor masking agent may be a 
solid or liquid. A liquid component is preferably dispersed within the 
filter assembly by an aerosol dispenser or by a wick. The filter assembly 
may also contain a moisture absorbent, such as silica gel, to remove 
excess moisture from the air and prevent condensation within the filter 
assembly. 
In a further embodiment shown in FIG. 3, the litter box includes a housing 
80 having a bottom panel 82 and upstanding litter bed side walls 84. A 
first support shelf 86 is positioned in the housing 80 and spaced above 
the bottom panel 82 to define an air space 83. The support shelf 86 may be 
a screen or other perforated plate-like member which extends substantially 
a width and length of the inner housing area. An odor absorbing material 
87 is supported on the first shelf. A second litter support shelf 88 is 
spaced above the first shelf 86 and extends the width and length of the 
inner housing area. The animal litter 93 is placed on the second shelf 
within the housing. The second shelf 88 is a screen or other suitable 
porous substrate to allow air to be drawn downwardly through the litter 
and the shelf. An air chamber 89 is defined by an outer wall 91 parallel 
to the end wall 84 of the housing 80. The air chamber is in communication 
with the air space 83. A hose connection 90 extends from the outer wall 91 
of the air chamber 89. Hose 92 is attached to the connection 90 and 
extends to a fan 94 to draw air from the air chamber 89 and air space 83 
and vents the air to a remote location, such as to the outside air. In 
operation, the fan 94 is actuated to produce a reduced pressure in the 
space between the first support shelf 86 and the bottom of the housing. 
Air is drawn from the upper surface of the housing downwardly through the 
litter bed to dry the litter and draw the odors away from litter. The 
odor-laden air is passed through the odor absorbing filter material to 
remove the odor-causing substances from the air. The deodorized air 
passing through air chamber 89 may then be vented to a location remote 
from the litter box or vented to the same room as the litter box. 
The litter box of FIG. 3 is preferably provided with a top closure 96 
having an opening 98 for the animal to enter the litter box. The top 
closure 96 may also be provided with a fringe curtain 100 to form a 
closure for the opening 98. 
The litter material may be a conventionally used litter such as granulated 
clay or vegetable matter, for example, shredded vegetation or wood chips. 
In a preferred embodiment of the invention the litter material is a 
substantially non-absorbent litter such that liquid waste will not be 
absorbed and can be easily dried by the flow of air through the bed. The 
litter may contain fragrances, disinfectants or other odor-masking 
materials. 
The operation of the device is readily apparent from consideration of the 
illustrated embodiments. In each of the embodiments the litter is 
supported on a foraminous substrate and air is drawn downwardly through 
substantially the entire bed of litter. The air is preferably drawn at a 
sufficient volume to dry the litter and draw the odors from the litter. In 
a preferred form of the invention the air is passed through an 
odor-absorbing filter material to remove the odor-causing substances from 
the air whereby the air can be vented back to the room. Alternatively, the 
deodorized air may be vented outdoors or to another remote location. The 
deodorized air may further be vented back to the top enclosure of the 
litter box. 
It will be appreciated that the operation of the device exhausts the litter 
box odors from the litter box and prevents the escape of the odors to the 
room. The removal of the odors and drying of the litter results in an 
increase in the useful life of the litter. The device may be constructed 
from any suitable material although synthetic polymeric materials such as 
polyethylene or polypropylene are preferred. The litter box is 
light-weight and easily assembled and easily cleaned.