Water filter abstract
A water filter including an inlet assembly which comprises a prefiltering
foam tip. The inlet hose includes an adjustable float and a weight
on the end of the hose which allows a given length at the end of
the inlet hose to extend below the surface of the water being filtered.
The water filter further includes a check valve assembly to relieve
pressure buildup inside the pump. A unique lever-action handle,
in combination with a rocking piston, allows efficient filtering
with few moving parts. The filter components are easily replaceable.
The main filter assembly is suspended resiliently at its periphery
to provide shock-absorbing characteristics. The filter also includes
an adaptor base which allows for a direct connect between the vessel
into which water is filter. The water filter also provides a unique
method of storing the inlet hose to render the water filter easy
to carry and prevent foreign objects and debris from entering into
the area of working parts.
Water filter claims
What is claimed is:
1. An inlet assembly in combination with a portable water filter,
an inlet conduit having a first end and a second end, said first
end being connected to a water filter, said second end being adapted
to be placed in water to be filtered;
a weight coupled to a second end of said inlet conduit, the weight
being adapted to maintain the second end below the surface of the
a float coupled to the inlet conduit at a position downstream of
the second end, said float maintaining the second end off the bottom
of the water, the float being located a given distance from the
weight to position the second end at a preferred position between
the top surface of the water and the bottom of the water from which
the water is to be drawn into the conduit.
2. A portable water filter according to claim 1 wherein the float
is movable along said inlet conduit to vary the distance between
the weight and the float to allow water to be drawn into the conduit
at a variety of depths.
3. A portable water filter according to claim 1 wherein said inlet
conduit is a flexible hose.
4. A portable water filter according to claim 1 wherein the weight
is a cage which surrounds the second end of the conduit.
5. The portable water filter of claim 4 including a first filter
medium removably retained within said cage, said first filter medium
having compressible pore sizes and being easily cleanable by compressing
and expanding the pore sizes in clean water.
6. The portable water filter of claim 4 wherein the cage is a coil
7. An inlet assembly in combination with a portable water filter,
an inlet conduit having a first end and a second end, said first
end being connected to a water filter, said second end adapted to
be placed in water to be filtered;
weight means for maintaining the second end below a surface of
the water; and
float means for maintaining the second end of the inlet conduit
off the bottom of the water source, the float means being positioned
relative to the weight means to fix a depth to which the second
end will extend below the surface of the water.
8. An inlet assembly according to claim 5 wherein the weight means
is coupled to a second end of said inlet conduit.
9. An inlet assembly according to claim 8 further comprising means
for adjusting the distance between the float means and the weight
10. An inlet assembly according to claim 7 wherein the conduit
comprises a flexible hose and the float means comprises a porous
Water filter description
This patent relates to filters, and more particularly, to portable
Background of the Invention
The need for filtering water for use, drinking, and consumption
to remove impurities has long been recognized. The traditional method
of purifying water is, of course, to pass the water through a water
treatment facility. Such purified water is, however, often unavailable
for persons engaged in international travel and for persons traveling
through the back country. Although water may macroscopically appear
clean and pure, it may nevertheless contain such impurities as bacteria,
pesticides, Giardia and other Protozoa. For backpackers and persons
traveling abroad, it is also desirable that the filter be small
and easily portable, yet capable of separating such impurities from
water drawn from a body of water, such as a lake or stream.
There are, however, several problems associated with traditional
portable water filters. One problem relates to the intake of water
into the water filter. There may be times when it is desirable to
draw water from a body of water at a particular depth where the
water is the purest. If, for example, a layer of scum lies on the
top of a body of water, it may be desirable to place the opening
of the intake hose several inches to several feet below the surface
to filter the best quality of water available. This will lengthen
the life of the filter and improve ultimately the quality of water
obtained. Alternatively, if the most contaminated water resides
close to the bottom of a body of water, it may be desirable to adjust
the depth of the opening of the intake hose so that it is located
close to the surface.
Another problem with respect to the intake of water into water
filter relates to dynamic bodies of water. In rivers and streams,
the opening of an inlet hose on the filter may bob up and down in
the water and remain, at least momentarily, above the surface of
the water which prevents drawing a full stream of water into the
Yet another problem associated with typical portable water filters
is the large contaminants and objects that are suspended in the
body of water from which water is drawn. Absent a preliminary means
for filtering the water before it enters into the intake hose, the
valves and pumping mechanism can be damaged and the filter rendered
useless in a relatively short period of time. Prescreening is thus
desirable where relatively large foreign objects, such as twigs,
leaves, heavy sediment or other large-sized objects, may be present
in the water to be filtered.
Traditional prefiltering methods involve a variety of types of
filters and screens. While these prefilters prevent large obstacles
from entering into the intake hose, they are commonly permanently
attached to the end of the intake hose and thus require backflushing
to clean the prefilter and free it of objects that have become lodged
in the filtering pores.
Still another problem associated with traditional portable water
filters relates to clogging of the main filter medium within the
filter body. Once the main filter medium has become clogged, which
is inevitable over the long run, the filtering (usually carried
out by some manner of pumping) becomes progressively more difficult.
In most pump models, for example, the water discharged from the
outlet remains the same for each full stroke of the piston being
pumped. The more clogged the filter medium, the more difficult it
is to pump. This increased difficulty of filtering water requires
more effort for each pumping stroke, which also increases the strain
on the parts and the operator. This pressure build-up within the
filter also places additional stress on the mechanical parts, which
can lead to failure of these parts.
Relief valves have heretofore been looked upon with disfavor in
conjunction with small, portable water filters because of the added
complexity to the water filter. A separate discharge tube is generally
required to direct the pressurized water being relieved outside
Another problem associated with conventional portable water filters
involves the mechanical means for forcing water through the filter.
Prior filtering devices have included piston-cylinder arrangements
where a rod is coupled to the piston so as to coincide with the
orthogonal axis of the cylinder. The rod is typically secured in
place relative to the cylinder by a wall with a central aperture
through which the rod must pass. This keeps the plane of the piston
perpendicular to the orthogonal axis of the cylinder at all times
while the piston moves back and forth in the cylinder.
Prior filters with piston-cylinder arrangements are usually actuated
by pumping the rod directly in and out of the cylinder as is done
by a typical hand-held tire pump. This type of ergonomic pumping
action is awkward and makes the overall process of filtering water
complicated and difficult.
Lever-action pumps have traditionally not been used for portable
water filters. Such lever-action pump handles require many linkage
parts to ensure that as the piston is moved back and forth, it constantly
remains in a plane perpendicular to the orthogonal axis of the cylinder.
To achieve this constant perpendicularity with the lever-action
handle, several linkage members are needed which increases the overall
friction, number of parts that may fail or wear out, and the overall
complexity of the filter device.
Still another problem associated with portable water filters relates
to the filter medium on the inside of the water filter itself. Over
time, the filter medium will become clogged with the filtered impurities.
Therefore, it is inevitable that the filter of the medium must be
changed or backflushed in some way. Removal and replacement of filter
mediums on traditional portable water filters is generally complicated
A further problem exists with respect to damage to the filter element
from impact resulting from, for example, dropping the filter. Water
filters have traditionally lacked the ability to absorb shock to
prevent damage to the filter medium. Carbon, a filter medium commonly
used in portable water filters, is particularly susceptible to breakage
There are also problems associated with the build up of impurities
inside the filter, which may later be discharged from the filter.
For example, carbon filters are commonly used in portable water
filters to filter bacteria and other microscopic impurities from
the water. Once used, some water will remain inside the carbon filter
medium. The water that remains in the carbon filter medium may act
as a breeding ground for bacteria. When this occurs toward the downstream
end of the carbon filter, the water initially discharged after a
long period of non-use may be contaminated with living organisms.
Some other problems associated with portable water filters involve
the vessel into which the filtered water is placed for use. Traditionally
portable water filters have been cumbersome and awkward in their
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a portable
water filter with an inlet hose that can be adjusted to draw water
from a body of water at a variety of depth.
Another object of the invention is to provide a prefiltering device
at the end of the inlet hose for preventing relative large-sized
impurities from entering into the intake hose.
Still another object of the present invention is to provide a water
filter with an inlet hose having an easily replaceable prefilter
at the end of the inlet hose.
Yet another object of the invention is to provide a method of relieving
pressure inside the water filter if the pressure exceeds a predetermined
Another object of the invention is to provide a means for redirecting
unfiltered water back down through the inlet hose when the filter
medium inside the main filter is clogged.
Still another object of the invention is to provide a water filter
through which water can be pumped using the same amount of force
regardless of the degree to which the filter medium has been clogged
Still another object of the invention is to provide a water filter
that includes a lever-action handle for pumping water through the
filter that is efficient, reduces friction, requires few parts,
is more ergonomic, and is less susceptible to breakdown.
Still another object of the present invention is to provide a cartridge
filter assembly that absorbs shock and minimizes damage due to impact.
Still another object of the invention is to provide a cartridge
filter assembly that is easily removable and economical to replace.
Another object of the invention is to provide a filter means for
removing regrowth bacteria that form inside the filter medium before
the water is completely discharged from the water filter.
Another object of the invention is to provide a water filter that
requires only one person to operate.
Yet another object of the invention is to provide a water filter
with a means for directly connecting the discharge end of the filter
to a container into which filtered water is discharged.
Another object of the invention is to provide a water filter with
a means for storing the inlet supply hose in a convenient manner
on the water filter.
Another object of the invention is to provide a water filter with
a means for sealing the inside of an open-ended piston-cylinder
arrangement so that dirt or other substances will be prevented from
entering into the piston-cylinder arrangement.
The foregoing objects and other objects that will become more apparent
from the detailed description that follows, are achieved by providing
a portable water filter having a float adjustably coupled to the
end of the intake hose and a weight on the end of the intake hose
so that the inlet opening can be placed at a given depth in the
body of water from which water is being drawn. A prefilter assembly
located at the end of the inlet hose prevents relatively large-sized
impurities from entering into the inlet hose.
The water filter further comprises a combination check/relief valve
which limits the flow of water in one
normal operation and discharges water back down the inlet hose
if excessive pressure builds up within the filter assembly due to
clogging. Water is forced the water filter by way of a lever-action
handle used an combination with a rocking piston to provide an easy-to-use,
efficient method for filtering the water.
A unique cartridge filter assembly is provided inside the water
filter which is supported at its periphery by opposite O-rings to
cushion the filter medium and prevent damage in the event the water
filter is subject to impact. The cartridge filter assembly is also
easy to remove and inexpensive to replace. The water filter also
includes a membrane filter located downstream of the cartridge filter
assembly which acts as a final filtering medium to prevent residual
regrowth bacteria from being discharged with the filtered water.
An additional feature of the water filter is an adapter base which
allows for the filter to be directly connected to a vessel into
which the filtered water can be discharged. The water filter further
includes a feature for conveniently storing the inlet hose on the
filter. A notch is provided on the lever-action handle so the hose
can be placed in the notch to secure the handle tightly against
the filter body which closes a door to prevent debris and other
material from entering into the cylinder body of the piston-cylinder
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view, partly in section, of the water filter
of the present invention.
FIG. 2 is an exploded perspective view, partly in section, of the
water filter of the present invention.
FIG. 3 is a partial sectional side view, taken along line 3--3
of FIG. 1 of the water filter of the present invention.
FIG. 3A is a cross-sectional view taken along line 3A--3A of FIG.
3 of the umbrella valve of the present invention.
FIG. 4 is a side elevational view, partly in section, of the hose
and inlet assembly of the present invention.
FIG. 5 is an exploded view of the inlet assembly of the present
FIG. 6 is a partial front elevational view, partly in section,
of the check/relief valve of the present invention.
FIG. 7 is a front elevational view, partly in section, of the check/relief
valve of the present invention.
FIG. 7A s a magnified view of the check/relief valve, shown in
FIG. 7 of the present invention.
FIG. 8 a partial side elevational view, partly in section, taken
along the line of 8--8 of FIG. 7 the piston-cylinder arrangement
of the present invention.
FIG. 9 is a partial side elevational view, partly in section, taken
along the line of 9--9 of FIG. 7 of the piston-cylinder arrangement
of the present invention.
FIG. 10 is a partial side elevational view, partly in section,
taken along the line of 10--10 of FIG. 7 of the piston-cylinder
arrangement of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1 the present invention relates generally
to a portable water filter 10 generally comprising an inlet assembly
12 a hose assembly 14 a relief valve assembly 16 a piston-cylinder
assembly 18 a main filter assembly 20 a discharge assembly 22
and a handle assembly 24. The water filter is small and lightweight
so that it can be used by persons traveling internationally or through
the backcountry, such as backpackers, yet the water filter is highly
effective for separating impurities from water commonly found in
the backcountry, such as bacteria, pesticides, Giardia and other
Referring now to FIGS. 4 and 5 the water filter 10 comprises an
inlet assembly 12 which includes a foam piece 26 partially inserted
into an end housing 28 which is inserted, in turn, into a supply
conduit or inlet hose 30. In one embodiment, the inlet hose is made
of a $5 flexible silicone material which is easy to bend to facilitate
wrapping the hose around the filter when not in use. It is understood,
however, that the hose could be made of any conventional material.
A coil spring or cage 32 encapsulates the combination of the hose,
the end housing, and the foam. The cage holds the inlet assembly
together, and particularly, the foam piece inside the inlet housing.
The cage further acts as a weight on the end of the hose. With reference
to FIG. 5 the cage has a narrowed portion 32a which gradually increases
to an enlarged portion 32b.
The end housing 28 comprises a cylindrical large diameter 34 frustoconical
portion 36 and a cylindrical, small-diameter portion 38. The final
element of the inlet assembly 12 is a compressible foam piece 26
having a plurality of pores 40. The pores are generally equal in
size when the foam piece is in an uncompressed state.
In assembling the inlet assembly 12 the narrowed portion 32a of
the cage 32 is slid over the end of inlet hose 30 after which the
small diameter portion 38 of the end housing 28 is inserted into
the hose. A portion of the foam 26 is then compressed (shown in
phantom in FIG. 5) and forced into the large-diameter portion 34
and the frustoconical portion 36 of the housing, respectively. The
cage is then slid back toward the end of the inlet hose so that
the enlarged portion 32b encapsulates the foam and the end housing.
The result is an inlet assembly that acts as a prefilter for preventing
large-sized particles, such as leaves, twigs, large pieces of sediment,
and the like, from entering into the inlet hose. This is first of
four filtering stages that take place in the present invention.
Large particles are prevented from entering into the hose by means
of the cage 32 and the exposed face of the foam 26 that extends
beyond the cage. The compressed foam inside the end housing creates
a reductive pore gradient (i.e., the pores become progressively
smaller in a downstream direction), which allows the inlet assembly
to filter progressively smaller-sized impurities as the water being
filtered passes downstream. The foam piece can easily be removed
and replaced relatively inexpensively. Alternatively the foam piece
is easy to remove and clean by merely squeezing the foam piece on
clean water. The inlet assembly provides an efficient, effective,
prefiltering device for the water filter 10.
With reference to FIGS. 2 and 4 the hose assembly 14 generally
comprises the inlet hose 30 and a float 42. The float is porous
so that it floats to maintain a portion of the inlet hose above
the surface of the water. The coil spring or cage 32 is preferably
made of metal, which provides a weight for the end of the intake
hose so that the intake end extends a given distance below the surface
of the body of water from which water is being drawn. This is particularly
advantageous when drawing water from rivers, streams and other moving
bodies of water.
The float 42 is slidably positioned on the hose 30 so that the
distance between the float and the end of the inlet hose can be
varied. Therefore, the end of the hose can be positioned at a specific
depth below the surface of the water to draw the highest quality
of water available, thus avoiding unnecessary filtering. This can
be advantageous if, for example, there is a layer of algae or debris
on top of the water, in which case it would be desirable to draw
water at a given depth below the surface. Alternatively, if the
amount of suspended particulate matter in the body of water increases
with depth, it would be desirable to draw water that is close to
the surface. The float, therefore, can be adjusted and the hose
simply placed in the body of water to draw water at a specific depth
without the need of holding the end of the hose at that particular
depth. This eliminates the need to use an extra hand (and thus an
extra person) to hold the hose while filtering the water.
With reference to FIGS. 1 2 6 and 7 the water filter 10 further
includes a combination check/relief valve assembly 16 which limits
the flow of water to one direction (i.e., into the filter) during
normal operation of the filter and relieves pressure that builds
up inside the filter assembly beyond a predetermined level. Such
pressure buildup is generally caused by clogging or some other type
of obstruction inside the filter which prevents normal flow of water
through the filter.
As shown in FIG. 6 the check/relief valve assembly 16 includes
an inlet hose barb 44 which comprises a threaded portion 46 a first
extension piece 48 and a pair of opposite flanges 50 which allow
the inlet hose barb to be easily removed from the valve housing
60 of the water filter unit 10. The threaded portion defines a cavity
52 which houses a valve spring 54. The valve spring is inserted
over a second extension piece 56 which holds the spring in place.
An end of a poppet 58 is inserted into the valve spring 54. An outer
surface of the poppet seats against the valve housing 60 during
normal filtering, as shown in FIGS. 6 and 7.
The poppet also defines an inner seat engaged by a valve ball 62
during the filtering process.
The valve housing 60 defines generally a valve cavity 64 which
extends beyond the normal position of the poppet 58. Water is drawn
from the inlet hose 30 to force the ball 62 away from the poppet
to allow water to enter into cavity 64. If water begins to escape
back into the poppet and inlet hose, the ball seats against the
popper, thus functioning as a one-way check valve. The valve housing
also comprises a stop 66 to limit movement of the valve ball 62
inside the valve cavity. If water pressure inside the filter exceeds
a safe, predetermined level, the ball will seat against the poppet
and the poppet is forced away from engagement with the valve housing
to allow pressurized water to flow around the valve spring 54 and
back into the inlet hose 30 as shown in FIG. 7A.
Referring to FIGS. 8-10 the piston-cylinder assembly 18 comprises
a cylinder 68 defined by a cylinder housing 69 a piston 70 and
a rod 72. An end of the cylinder housing opposite the piston is
open to allow for the free of the rod. An oversized O-ring 74 is
secured to the periphery of the piston to seal the space in between
the piston and cylinder.
Actuation of the piston 70 relative to the cylinder 68 is caused
by a lever-action handle 76 pivotally mounted to the water filter
at pivot point 78 and pivotally mounted to the rod 72 at pivot point
80. In traditional piston-cylinder arrangements the piston moves
back and forth inside the cylinder so that the plane of the piston
remains constantly perpendicular to the longitudinal axis of the
cylinder. When using a lever-action handle to actuate the piston,
however, multiple linkage members are required in order to maintain
the piston constantly perpendicular with respect to the cylinder,
along with an additional support toward the rear of the cylinder
(typically a rear wall with an aperture) to maintain the rod in
a centered position inside the cylinder.
In the present piston-cylinder assembly 18 the need for additional
linkage members and additional structure in the cylinder have been
eliminated by use of an open 75 of the cylinder and a large size
O-ring 74. The O-ring 74 allows the piston to effectively rock back
and forth inside the cylinder without any leakage around the piston
in between the periphery of the piston end wall of the cylinder.
The rod is allowed to articulate freely because of the open end
75 of the cylinder.
As shown in FIG. 10 an expansion stroke of the piston 70 is caused
by articulating the handle 76 away from the filter body 10 which
increases the volume inside cylinder cavity 82. This increase in
volume causes water to be drawn into the filter through the inlet
hose 30 through the valve assembly 16 (FIGS. 6-7A), through the
valve housing 60 and into cavity 82 via passageway 84 in the valve
housing. The expansion stroke of the piston is limited by an abutment
surface 86 of the handle 76.
An expansion stroke of the piston 70 is shown in FIG. 10. In this
position, the top of the piston 70 is inclined with respect to the
vertical to form an angle .alpha.. Normally, any "rocking"
movement of the piston relative to a pependicular plane as defined
by the cylinder would cause leakage around the outside of the piston.
The O-ring 74 is oversized, however, to accommodate the rocking
motion of the piston and seal the area in between the periphery
of the piston and inside of the cylinder 68.
FIG. 8 shows a compression stroke of the piston wherein the bottom
of the piston face is angled relative to the vertical, which is
represented by angle .beta.. FIG. 9 shows the face of the piston
70 in a generally vertical orientation midway between the full compression
and full expansion strokes.
Referring now to FIG. 3 once the water has entered into cavity
82 as a result of an expansion stroke of the piston 70 water will
then be forced into the main filter assembly 20 by a compression
stroke of the piston-cylinder assembly. The compression stroke causes
the pressure inside of cavity 82 to increase, which forces open
an umbrella valve 88 (FIG. 3A) coupled to the cap 93 through aperture
95 which allows water to enter a top cavity 90 through a pair of
openings 91 in the cap 93 coupled to the main filter housing.
The water then proceeds down through a filter screen assembly 98
which generally includes at least one fine mesh screen 92 structurally
supported by a coarse mesh screen 94. Other screen material may
be nonwoven or sintered filtering media, for example. The filter
screen assembly will, in one embodiment, separate 10 micron to 30
micron-sized particulate matter. The fine mesh screen, and possibly
multiple fine mesh screens, along with the coarse screen are joined
together at their peripheries by an annular ring 96 to form the
complete filter screen assembly. The screen elements can be discs
of woven or woven and bonded material. The filter screen assembly
thus comprises the second stage of the overall filtering that takes
place in the water filter 10.
In the alternative, if the downstream carbon depth medium, such
as the carbon filter 110 is capable of multiple cleanings and of
holding particulate matter on its surface, then a filter screen
assembly may be eliminated.
Immediately below the filter screen assembly is a carbon filter
or carbon depth media assembly having a top end cap 102 and a bottom
end cap 104 to form a filter cartridge assembly 110. The top end
cap defines a plurality of L-shaped slots 106 extend radially outwardly
of the top end cap in all directions to provide multiple passageways
for water to flow into a peripheral cavity 108 which surrounds the
periphery of a carbon filter 110. Although carbon is used as a filter
medium in one embodiment, it is understood that any suitable filter
medium such as a diatomaceous earth or ceramics may be used. Water
flows from the periphery of the carbon filter radially inwardly
to a central cavity 112 defined by the carbon filter. The bottom
end cap 104 defines a central aperture 114 through which water drains.
The carbon filter is the third stage of filtering that occurs in
the water filter 10 and is capable of separating 0.5 micron and
larger-sized impurities. Specifically, the carbon filter is capable
of removing chemical microbiological and particulate matter.
The carbon filter cartridge assembly 100 is supported by a pair
of O-rings 116 placed around the top end cap 102 and bottom end
cap 104 respectively. The O-rings 116 support the carbon filter
assembly at its periphery by engaging the inside wall of the filter
housing 89. The O-rings 116 are the only means for supporting the
carbon filter assembly. In one embodiment, the O-rings 116 are made
of a resilient material, such as rubber, to provide a means for
absorbing shock to the water filter due to impact from dropping
or the like, which prevents damage to the carbon filter assembly.
This is particularly important since the water filter may be subject
to abuse due to the backcountry environment in which the water filter
10 is intended to be used and because of the fragile nature of many
With reference to FIG. 3 a fourth and final filtering stage is
provided at the bottom of the main filter housing 89. An adaptor
base 117 is threadably connected to the main filter housing 89 to
house a membrane filter cartridge 118. A threaded extension member
120 extending from the membrane filter cartridge is threadably secured
to a threaded aperture 122 in the central portion of the adaptor
base. An O-ring 124 seals the area in between the membrane filter
cartridge and the adaptor base 117.
The membrane filter cartridge 118 houses a membrane filter 126
through which the water is forced before being discharged from the
water filter 10. The membrane filter has the capability of separating
impurities of 0.1 micron and larger. In general, use of a membrane
to separate contaminants reduces the energy required to filter a
given volume of water as compared to a depth filter medium.
After the membrane filter assembly 118 is threaded into the adaptor
base 117 a barb 128 extends below the bottom surface of the adaptor
base 117. A cap 130 includes a ring 132 which is inserted over
the barb 128. The cap then remains constantly with the water filter
10 so that the barb can be covered to prevent contaminants from
entering into the discharge passageway.
As shown in FIGS. 2 and 3 the adaptor base 117 can be directly
connected to a vessel into which filtered water can be discharged.
A vessel with a correspondingly threaded top can simply be threaded
into threaded portion 136 of the adaptor base 117. This eliminates
the need to use an extra person to hold the vessel, and eliminates
the need to hold the filter directly over a vessel when filtering
water. Alternatively, a discharge hose 134 can be inserted over
the barb 128.
With regard to the operation of the piston-cylinder assembly 18
the present invention requires the cylinder 68 to have an open end
75 so there is no structural support of the rod 72 at the rear of
the cylinder housing 69. This open end creates the possibility that
dirt or other debris will enter into the cylinder and damage the
sealing surface. However, the handle assembly 24 includes a door
136 which closes upon a full compression stroke of the piston 70
to prevent any debris from entering into the cylinder 68.
To facilitate storage of the hose 30 and to ensure that the door
136 of the handle assembly 24 remains closed when the pump is not
being operated, the handle assembly 24 includes a notch 138 (FIGS.
1 and 2) into which a portion of the hose 30 can be inserted after
the hose has been wrapped around the water filter 10. The size of
the notch is slightly less than the size of the hose so that the
hose must be forced into the notch, which holds the hose tightly
in place. This ensures that the handle will remain close to the
filter housing 89 and the door will remain closed when the filter
is not being used to prevent dirt and debris from entering into
In operation, water is filtered through the water filter 10 by
forcing the lever-action handle 76 away from the filter, which results
in an expansion stroke of the piston 70 thus enlarging the volume
of cylinder cavity 82 (FIG. 10). Water then enters into the inlet
assembly 12 (FIG. 4) by passing through the foam 26 the end housing
28 and the inlet hose 30 The water then passes through the relief
valve assembly 16 (FIG. 6) and forces the valve ball 62 away from
the poppet 58 to enter into valve cavity 64. The water passes from
the valve cavity 64 through passageway 84 and into the cylinder
cavity 82 (FIG. 10). The lever-action handle is then forced toward
the filter, which results in a compression stroke of the piston
70. This increases the fluid pressure in the cylinder cavity 82
which causes the water to flow through apertures 91 by forcing the
umbrella valve 88 downward so water can pass into top cavity 90.
The water then flows through the filter screen assembly 98 into
the L-shaped grooves 106 and into the cavity 108 surrounding the
carbon filter 110. The water next passes radially inwardly through
the carbon filter and into the central cavity 112 through the central
aperture 114 of the bottom end cap 104 and into the cavity 119
surrounding the membrane filter cartridge 118. Water then passes
through the membrane filter 126 and is discharged through the opening
in the barb 128.
If the filter becomes clogged, either partially or completely,
the increased pressure due to the compression stroke of the piston
70 will cause the valve ball (FIG. 6) to become seated inside the
poppet 58 which will normally prevent water from passing back down
through the intake hose 30 and if the pressure reaches an excessive
level, the poppet is pushed away from the valve housing 60 and water
is forced around the outside of the poppet and back into the inlet
hose 30 (FIG. 7A). This reduces the pressure on the lever-action
handle 76 and allows the handle to be articulated with approximately
the same amount of force as when there is no excessive pressure
buildup. The amount of water passing through the filter will, of
course, be reduced when the filter is clogged or partially clogged,
but the force required to articulate the handle in a compression
stroke will remain relatively constant.
While the preferred embodiments of the water filter have been described
above and are shown in the drawings, it is understood that variations
will be apparent to those skilled in the art. Accordingly, the present
invention is not to be limited to the specific embodiments illustrated
in the drawings and discussed above.