Water filter abstract
A water filter including a packing ring to seal up the gap between
the casing and the top cover, which packing ring having downward
projecting strips fitted into respective notches on the casing to
stop the packing ring against rotary motion relative to the casing,
two water sealing devices respectively mounted on a water outlet
pipe on the top cover and a stub tube on the casing and having respective
flanges forced to engage two opposite ends of the filter element
and to prevent unfiltered water from entering the longitudinal center
through hole of the filter element.
Water filter claims
I claim:
1. A water filter comprising a cylindrical casing having a bottom
wall and a top opening, a filter element received inside said cylindrical
casing and having a top end, a bottom end and a longitudinal center
through hole extending from said top end to said bottom end, a top
cover fastened to said cylindrical casing to hold down said filter
element, said cover having a water inlet port for guiding water
into said cylindrical casing to the filter element and a water outlet
for guiding filtered water out of said cylindrical casing from the
filter element, said water outlet comprising a water outlet pipe
which projects downwardly from the cover into said longitudinal
center through hole at said top end of said filter element, said
cylindrical casing including a stub pipe extending from said bottom
wall upwardly into said longitudinal center through hole at the
bottom end of said filter element, a packing ring sealed in an annular
groove in said cylindrical casing between said cylindrical casing
and said top cover, a first water sealing device sealed between
said cylindrical casing and said bottom end of said filter element,
and a second water sealing device sealed between said top cover
and said top end of said filter element, wherein said packing ring
comprises a downwardly extending annular longitudinal flange integrally
formed with an annular horizontal flange wherein said horizontal
flange includes a plurality of downward projecting strips respectively
fitted into a plurality of notches inside said cylindrical casing
to stop said packing ring from rotary motion relative to said cylindrical
casing; said second water sealing device comprises a tube portion
sleeved onto said water outlet pipe of said top cover and having
a first tube portion end abutting the top cover and an opposite
tube portion end extending into the top end of the longitudinal
center through hole of said filter element, said second water seal
device further comprising an outward ring flange integrally formed
with said first tube portion end and stopped between said top cover
and said filter element, and a downwardly extending annular flange
raised from the outward ring flange of said second water sealing
device and engaging the top end of said filter element; said first
water sealing device comprises a tube portion sleeved onto said
stub tube inside said cylindrical casing at said bottom wall and
having a first tube portion end abutting the bottom wall and an
opposite tube portion end extending into the bottom end of the longitudinal
center through hole of said filter element, said first water sealing
device further comprises an outward ring flange integrally formed
with said first tube portion end of said first water seal device
and stopped between said bottom wall of said cylindrical casing
and said bottom end of the filter element, and an upwardly extending
annular flange raised from the outward ring flange of said first
water sealing device and engaging the bottom end of said filter
element.
2. The water filter of claim 1 wherein said top cover comprises
an annular groove at a bottom around said water outlet pipe; said
second water sealing device comprises an upwardly extending annular
flange raised from the outward ring flange of said of said second
water sealing device and fitted into the annular groove on said
top cover.
Water filter description
BACKGROUND OF THE INVENTION
The present invention relates to water filters, and relates more
particularly to such a water filter having sealing means that can
effectively seal up the gap between the casing and the top cover
of the water filter and prevent unfiltered water from enter the
longitudinal center through hole of the filter element to mix with
filtered clean water.
A variety of water filters have been disclosed, and have appeared
on the market. FIGS. 1 and 2 show a water filter according to the
prior art, which is generally comprised of a cylindrical casing
having an inner thread around the top opening, a filter element
received in the cylindrical casing, a top cover having an outer
thread threaded into the inner thread of the cylindrical casing
to hold down the filter element, and a packing ring sealed between
the top cover and the cylindrical casing. The filter element has
a longitudinal center through hole and two annular grooves on two
opposite ends thereof. The cylindrical casing has a stub tube on
the inside at the bottom inserted into the bottom end of the longitudinal
center through hole of the filter element, and an annular flange
fitted into the annular groove on the bottom end of the filter element.
The top cover has a water outlet pipe fitted into the top end of
the longitudinal center through hole of the filter element, and
an annular flange fitted into the annular groove on the top end
of the filter element. This structure of water filter is still not
satisfactory in function because the packing ring will be twisted
to deform, when the top cover is threaded into the inner thread
of the cylindrical casing. Frequently deforming the packing ring
will shorten the service life of the packing ring and affect its
performance. Furthermore, because the annular flanges of the top
cover and the cylindrical casing are of rigid structure, they deform
the two opposite ends of the filter element when installed. When
the filter element is installed in the cylindrical casing again
after every washing process, the annular flanges of the top cover
and the cylindrical casing must be accurately stopped at the dents
on the two opposite ends of the filter element which was formed
by the squeezing of the annular flanges, or water leakage will happen.
FIGS. 3 and 4 show another structure of water filter designed to
eliminate the aforesaid drawbacks, in which the packing ring has
a downward annular flange fitted into an annular groove around the
inside wall of the cylindrical casing; two water sealing ring respectively
mounted within an annular groove on the bottom wall of the top cover
and an annular groove on the bottom wall of the cylindrical casing
and sealed between the two opposite ends of the filter element and
the bottom walls the top cover and cylindrical casing. The drawback
of this structure of water filter is its complicated assembly process.
SUMMARY OF THE INVENTION
The present invention has been accomplished under the circumstances
in view. According to one aspect of the present invention, the packing
ring which seals up the gap between the cylindrical casing and the
top cover has a plurality of downward projecting strips fitted into
respective notches on the cylindrical casing, and therefore the
packing ring will not be twisted when the top cover is fastened
to the cylindrical casing. According to another aspect of the present
invention, two water sealing devices are respectively mounted on
the water outlet pipe on the top cover and the stub tube on the
cylindrical casing. The water sealing devices have a respective
outward flange stopped between the filter element and the top cover
or cylindrical casing, and a respective annular flange raised from
the respective outward flange and engaging one end of the filter
element to prevent unfiltered water from mixing with filtered water
.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded view of a water filter according to the prior
art;
FIG. 2 is an assembly view in section of the water filter shown
in FIG. 1;
FIG. 3 is an exploded view of another structure of water filter
according to the prior art;
FIG. 4 is an assembly view in section of the water filter shown
in FIG. 3;
FIG. 5 is an exploded view of a water filter according to the present
invention;
FIG. 6 is an assembly view in section of the water filter shown
in FIG. 5;
FIG. 7 is bottom view of a packing ring according to the present
invention;
FIG. 7A is a sectional view taken along line 7A--7A of FIG. 7;
FIG. 8 is a top view of the cylindrical casing shown in FIG. 5;
and
FIG. 8A is a sectional view taken along line 8A--8A of FIG. 8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 5 and 6 a water filter in accordance with the
present invention is generally comprised of a cylindrical casing
10 a filter element 20 received inside the casing 10 a top cover
30 fastened to the cylindrical casing 10 to hold down the filter
element 20 and a packing ring 1 sealed between the cylindrical
casing 10 and the top cover 30.
Referring to FIGS. 5 through 8 the packing ring 1 is comprised
of a longitudinal flange 11 and a horizontal flange 12. The horizontal
flange 12 comprises a plurality of downward projecting strips 13a.
The cylindrical casing 10 comprises an annular groove 101 around
the inside wall near the top opening, an annular stop wall 102 surrounded
by the annular groove 101 and a plurality of inside notches 103a
spaced around the annular stop wall 102 at a lower elevation. When
the packing ring 1 is fastened to the cylindrical casing 10 the
longitudinal flange 11 is fitted into the annular groove 101 to
form a first sealing line, the horizontal flange 12 is stopped against
the annular stop wall 102 to form a second sealing line, and the
downward projecting strips 13a are respectively fitted into the
inside notches 103a to stop the packing ring 1 from rotary motion
relative to the cylindrical casing 10.
Referring to FIGS. 5 and 6 the top cover 30 comprises a water
inlet port 300 a water outlet pipe 301 an annular groove 3 at
the bottom around the water outlet pipe 301. The cylindrical casing
10 comprises a stub tube 100 on the inside at the bottom. A first
water sealing device 4 and a second water sealing device 5 are respectively
mounted around the water outlet pipe 301 and the stub tube 100 and
sealed between the filter element 20 and the top cover 30/cylindrical
casing 10. The water sealing device 4 or 5 comprises a tube 41 or
51 an outward flange 42 or 52 raised around the tube 41 or 51
and an annular flange 43 or 53 raised from the outward flange 42
or 52 at one side around the tube 41 or 51. The first water sealing
device 4 further comprises an annular flange 44 raised from the
outward flange 42 at an opposite side relative to the annular flange
43. When the tubes 41 and 51 of the first and second water sealing
devices 4 and 5 are respectively mounted around the water outlet
pipe 301 and the stub tube 100 the annular flange 44 of the first
water sealing device 4 is fitted into the annular groove 3 on the
top cover 30. After installation, the tubes 41 and 51 are respectively
inserted into the two opposite ends of the longitudinal center through
hole 200 of the filter element 20 and the annular flanges 43 and
53 of the first and second water sealing devices 4 and 5 are respectively
forced into the two opposite ends of the filter element 20 around
the longitudinal center through hole 200.
Referring to FIG. 6 again, when water is guided into the water
filter through the water inlet port 300 it is forced to move through
the filter element 20 into the longitudinal center through hole
200 and then forced out of the water filter through the water outlet
pipe 301. Because the two opposite ends of the filter element 20
is properly sealed by the water sealing devices 4 and 5 filtered
water does not flow out of the filter element 20 in the reversed
direction. Therefore, only filtered clean water is allowed to flow
out of the water outlet pipe 301 for use. Furthermore, the installation
of the packing ring 1 effectively seals up the gap between the top
cover 30 and the cylindrical casing 10. |