An orally operable, portable, water filtration device. The device includes an elongated tube having an inlet end and an outlet end. The inlet end includes a screen whose openings are in the form of slits. The slits have a width of about 0.005.+-.0.003 inch and filter out pollutants of at least that size. The tube also has an integrally formed internal ledge onto which is disposed a porous polypropylene membrane having a pore size of about 5-8 microns. A bed of granulated activated carbon with a grind size of 1230 is disposed inside the tube between the inlet end and the porous polypropylene membrane in a 7:1 ratio (bed height:bed diameter). A mouthpiece, which has an inlet and an outlet, is mounted over the outlet end of the elongated tube so that the mouthpiece and the elongated tube are in fluid communication. To use the device, the inlet end of the tube is inserted into water and suction is applied to the outlet of the mouthpiece.

BACKGROUND OF THE INVENTION 
The present invention relates to an orally operable, portable, water 
filtration device. 
With each passing day, man-made chemicals and contaminants are introduced 
into our water supply. Many of these pollutants are unhealthful to drink 
and/or adversely affect the taste of water. Typically, travelers, hunters, 
and the like who wish to filter their water use some sort of orally 
operable, portable, water filtration device, such as a water filtration 
straw, which removes the pollutants from the water as it is sucked through 
the straw to the user's mouth. One type of water filtration straw 
comprises a hollow elongated tube. A porous material, such as felt or foam 
is inserted into the bottom end of the tube and is held in place by a 
screen mounted on the bottom end of the tube. Additional foam or felt is 
inserted into the top end of the tube and is held in place by a second 
screen mounted thereover. Filter material, such as granulated activated 
carbon, is disposed within the tube between the foam and/or felt 
materials. 
In U.S. Pat. No. 4,767,544 to Hamblin, an orally operable water filter is 
described. The water filter includes an outer covering formed of a 
flexible, water impervious material and which defines an elongate 
enclosure. A flexible microporous filter membrane, having a pore size of 
not more than one micron, is disposed within the elongate enclosure and 
divides the enclosure into respective fluid inlet and fluid outlet 
compartments, such that the outlet may be placed in the mouth of the user 
and fluid inlet may be contacted with a source of water to be filtered by 
drawing the water through the filter using oral suction. Furthermore, the 
filter includes a flexible separator, disposed at least in the outlet 
compartment, for preventing the blocking of fluid over the surface of the 
filter membrane. 
In U.S. Pat. No. 4,298,475 to Gartner, a portable water purifier is 
described. The water purifier comprises an elongated tube having a 
diameter of a size as to allow suction to be applied by a user's mouth, 
the tube having an interior conduit connecting an upper outlet and a lower 
inlet, the conduit having successive adjacent sections from the inlet and 
the outlet, a first section containing a primary filter material for 
removing particulate matter, a second section containing an iodinated 
cation ion exchange resin for removing harmful bacteria, viruses, and the 
like, a third section containing a secondary filtration material for 
removing additional particulate material, a fourth section containing 
activated carbon granules for removing undesirable odors, tastes and 
hydrocarbons, and a fifth section containing a secondary filter material 
for removing substantially all remaining particulate matter, whereby on 
the application of suction when the lower inlet is inserted into a source 
of contaminated water, the contaminated water is treated to permit the 
ingestion of water directed from the upper outlet. 
In U.S. Pat. No. 1,333,011 to Crady, an individual filter is described. The 
individual filter comprises a pair of detachable sections telescopically 
arranged, one of which is provided with a mouth piece, each of the 
sections being provided at their outer ends with permanently attached 
screens, while their opposed or inner ends are provided with removable 
screens, the sections having the space between the screens filled with a 
filtering element preferably in the form of charcoal. The removable 
screens are each composed of a ring with a fine wire mesh secured to one 
edge thereof and a loop also secured to the rings for the purpose of 
providing for the convenient removal of the screens, the screens being 
held in position within the tubular members by screws or other fastening 
devices passing through the members and engaging the rings. 
In U.S. Pat. No. 1,000,332 to Dyer, a pocket filter is described. The 
pocket filter comprises a tubular body, end foraminous cap members carried 
thereon, filtering material interposed between the cap members, a 
telescopic member secured to the tubular body and adapted to prevent 
displacement of one of the caps, one section of the telescopic member 
being provided with a slot adjacent to one terminal thereof, and a 
foraminous member adapted to be received by the slot, the member being 
prevented from displacement by the tubular body as set forth. 
Other patents of interest include U.S. Pat. Nos. 4,894,154, 4,769,143, 
4,578,187, 4,505,310, 4,369,512, and 4,309,992. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a new and improved 
orally operable, portable, water filtration device. 
It is another object of the present invention to provide an orally 
operable, portable, water filtration device having a minimal number of 
parts. 
It is still another object of the present invention to provide an orally 
operable, portable, water filtration device which is easy to assemble, 
which can be mass produced, and which is easy to use. 
An orally operable, portable, water filtration device constructed according 
to the teachings of the present invention comprises an elongated tube 
having an inlet end and an outlet end, the inlet end including an 
integrally formed screen. A porous membrane is mounted inside the 
elongated tube proximate to the outlet end, and a quantity of filtering 
material is disposed inside the elongated tube between the inlet end and 
the porous membrane. 
Various features and advantages will appear from the description to follow. 
In the description, reference is made to the accompanying drawings which 
form a part thereof, and in which is shown by way of illustration, a 
specific embodiment for practicing the invention. This embodiment will be 
described in sufficient detail to enable those skilled in the art to 
practice the invention, and it is to be understood that other embodiments 
may be utilized and that structural changes may be made without departing 
from the scope of the invention. The following detailed description is, 
therefore, not to be taken in a limiting sense, and the scope of the 
present invention is best defined by the appended claims.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring now to the drawings and in particular to FIG. 1, there is shown 
one embodiment of an orally operable, portable, water filtration device, 
the device being constructed according to the teachings of the present 
invention and represented generally by reference numeral 11. 
Device 11 includes a filtration assembly 13 and a mouthpiece 15. Referring 
now to FIG. 2, there is shown a section view of filtration assembly 13. 
Filtration assembly 13 includes an elongated tube 17, which is a unitary 
structure made of polystyrene or another similar material. Tube 17 has an 
inlet end 21 and an outlet end 23. Tube 17 also has an integrally formed 
internal ledge 24 for mounting thereon a porous membrane to be described 
below. Preferably, tube 17 has a length of approximately 6 inches, an 
inner diameter of approximately 0.5 inch, and a wall thickness of 
approximately 0.025.+-.0.005 inch. In addition, tube 17 preferably tapers 
inwardly approximately 1/32 inch in the direction of inlet end 21. 
Referring now to FIGS. 3 and 4, it can be seen that inlet end 21 includes 
an integrally formed screen 22 whose openings are preferably in the form 
of slits 25. Preferably, slits 25 have a width of approximately 
0.005.+-.0.003 inch and a length varying from approximately 1/16 to 1/4 
inch (depending on their location on the screen) so that slits 25 are 
large enough to permit the entry of water into tube 17 but, at the same 
time, are small enough to prevent the entry of many types of pollutants 
thereinto and, as will be discussed below, are small enough to prevent the 
leakage of filtering material from tube 17. Preferably, slits 25 are 
spaced apart by approximately 0.055.+-.0.005 inch. 
Screen 22 also includes a diametrically disposed rib 27. Rib 27 provides 
support to screen 22 in order to prevent slits 25 from becoming damaged by 
the trapping of pollutants therebetween. Rib 27 also serves to elevate 
tube 17 so that when device 11 is used, for example, to drink water from a 
glass having a flat bottom, a vacuum is not created between the bottom of 
the tube and the bottom of the glass. Preferably, rib 27 has a width of 
approximately 1/32 inch and a height of approximately 1/16 inch. 
Referring back to FIG. 2, assembly 13 also includes a bed of filtering 
material 29, such as granulated activated carbon (G.A.C.), G.A.C. 
impregnated with metallic silver or other similar materials. It has been 
found that optimal results (measured in terms of filtering efficacy and 
the ease with which water is sucked through the device) are obtained when 
the ratio of bed height to bed diameter is approximately 7:1 and when 
G.A.C. (or G.A.C. impregnated with metallic silver) of the grind size 1230 
is used. 
Finally, assembly 13 includes a porous membrane 31 disposed on top of lip 
24. Membrane 31, which preferably has a porosity of approximately 5-8 
microns, is preferably made of polypropylene or other similar materials. 
Referring now to FIGS. 5-7, there are shown various views of mouthpiece 15. 
Mouthpiece 15, which is an elongated, hollow, unitary structure preferably 
2.375 inches in length and made of polystyrene or another similar 
material, includes a generally cylindrical base portion 35 and an 
oval-shaped tip 36, the tip being designed for insertion into the mouth of 
a person. Base portion 35 includes an inner wall 37 and a top wall 39 
which together define a chamber 40 into which the top of assembly 13 is 
inserted for assembly. 
Mouthpiece 15 includes an inlet 43 and an outlet 45. Inlet 43 is so 
disposed that, when mouthpiece 15 is mounted onto assembly 13, the inside 
of mouthpiece 15 and the inside of assembly 13 are in fluid communication. 
Outlet 45 is preferably a circular hole having a diameter of 0.100 inch. 
To use the subject invention, inlet end 21 is inserted into a source of 
water. The user then places his mouth over mouthpiece 15 and, much as in 
the nature of a straw, sucks the water inward. Slits 25 prevent most of 
the pollutants in the water having a size at least 0.005.+-.0.003 inch 
from entering tube 17. The water that does enter tube 17 is then subjected 
to filtering material 29, which removes many of the pollutants having a 
size at least 5-10 microns and which removes odors and tastes from the 
water, making the water more palatable to drink. Finally, the water is 
subjected to membrane 31 which removes most of the remaining pollutants 
having a size at least 5-8 microns. The water, thus filtered, is then 
sucked up through oultet 45 and into the mouth of the user. 
In another embodiment (not shown), purifying material, in addition to 
filtering material 29, is disposed inside tube 17. 
The embodiments of the present invention are intended to be merely 
exemplary and those skilled in the art shall be able to make numerous 
variations and modifications to it without departing from the spirit of 
the present invention. All such variations and modifications are intended 
to be within the scope of the present invention as defined in the appended 
claims.