U.S. patent application number 09/729707 was filed with the patent office on 2001-04-26 for filter apparatus for canister.
This patent application is currently assigned to Toyo Roki Seizo Kabushiki Kaisha. Invention is credited to Suzuki, Hayato.
Application Number | 20010000374 09/729707 |
Document ID | / |
Family ID | 26373172 |
Filed Date | 2001-04-26 |
United States Patent
Application |
20010000374 |
Kind Code |
A1 |
Suzuki, Hayato |
April 26, 2001 |
Filter apparatus for canister
Abstract
A filter apparatus 20 is connected to an outlet portion of a
canister mounted on a fuel supply system for a vehicle. A housing
21 and a filter element 30 are provided. The housing 21 has a
connection-opening portion 25 connected to the outlet portion and
atmospheric release opening portion 26 communicating with the
atmosphere. The filter element 30 is received in the housing 21 so
that one end of a hollow portion 31a passing through the center of
a filter body 31 is connected to the connection opening portion 25
from the inner side of the housing 21. The hollow portion 31a of
the filter element 30 is utilized as a part of a passage for
introducing fluid, which has been introduced from the connection
opening portion 25 into the housing 21, into the atmospheric
release opening portion 26. There is provided at the other end of
the hollow portion 31a a one-way valve 33 permitting the fluid to
discharge from the side of the other end of the hollow portion 31a
and preventing the fluid from flowing from the side of the
above-mentioned other end into the hollow portion 31a.
Inventors: |
Suzuki, Hayato;
(Hamakita-shi, JP) |
Correspondence
Address: |
YOUNG & THOMPSON
745 SOUTH 23RD STREET 2ND FLOOR
ARLINGTON
VA
22202
|
Assignee: |
Toyo Roki Seizo Kabushiki
Kaisha
Shizuoka-ken
JP
|
Family ID: |
26373172 |
Appl. No.: |
09/729707 |
Filed: |
December 6, 2000 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
09729707 |
Dec 6, 2000 |
|
|
|
09250291 |
Feb 17, 1999 |
|
|
|
6183526 |
|
|
|
|
Current U.S.
Class: |
55/311 ; 55/312;
55/313 |
Current CPC
Class: |
B01D 53/0415 20130101;
F02M 25/0854 20130101; B01D 2253/102 20130101; B01D 2259/4566
20130101; B01D 2257/702 20130101; B01D 53/72 20130101; B01D
2259/4516 20130101 |
Class at
Publication: |
55/311 ; 55/312;
55/313 |
International
Class: |
B01D 046/42 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 17, 1998 |
JP |
P10-34374 |
Nov 18, 1998 |
JP |
P10-328194 |
Claims
What is claimed is:
1. A filter apparatus for a canister, which is to be connected to
an outlet portion of the canister mounted on a fuel supply system
for a vehicle, comprises: a housing having a connection opening
portion, which is to be connected to said outlet portion and an
atmospheric release opening portion communicating with an
atmosphere; a filter element received in said housing; wherein:
said filter element is provided with a filter body having a
filtering function and a flat plate shape, and with a partition,
which divides, in cooperation with said filter body, an inside of
said housing into a clean-side zone communicating with said
connection opening portion and a dirty-side zone communicating with
said atmospheric release opening portion; said partition is
provided with a one-way valve, which permits fluid to pass from
said clean-side zone to said dirty-side zone and prevents said
fluid from passing from said dirty-side zone to said clean-side
zone; said partition being joined to said filter body so as to
surround an outer periphery of said filter body; and said partition
being joined over its entire periphery to an inner wall of said
housing.
2. A filter apparatus for a canister, which is to be connected to
an outlet portion of the canister mounted on a fuel supply system
for a vehicle, comprises: a housing having a connection opening
portion, which is to be connected to said outlet portion and an
atmospheric release opening portion communicating with an
atmosphere; a filter element received in said housing; wherein:
said filter element is provided with a filter body, which has a
filtering function and a flat plate shape and with a partition
connected to said filter body so as to surround said filter body;
said partition is joined over its entire periphery to an inner wall
of said housing so as to divide an inside of said housing into a
clean-side zone communicating with said connection opening portion
and a dirty-side zone communicating with said atmospheric release
opening portion; and said partition is provided with a one-way
valve, which permits fluid to pass from said clean-side zone to
said dirty-side zone and prevents said fluid from passing from said
dirty-side zone to said clean-side zone.
3. The apparatus as claimed in claim 2, wherein: said partition is
provided with a tubular member, which connects said clean-side zone
with said dirty-side zone; said tubular member is provided on its
forward end portion with a valve seat, which extends in a
perpendicular direction when said filter apparatus is kept in its
used condition; and said one-way valve has a structure in which
said one-way valve can come into close contact with said valve seat
by its own weight to close said tubular member or can be apart from
said valve seat under a function of pressure of the fluid
introduced from said connection opening portion into said
clean-side zone.
Description
BACKGROUND OF THE INVENTION
1. 1. Field of the Invention
2. The present invention relates to a filter apparatus, which is to
be used in combination with a canister for removing toxic
substances from a vaporous fuel generated in a fuel tank or the
like for an internal combustion engine.
3. 2. Description of the Related Art
4. A vaporous fuel generated in a fuel tank mounted on a vehicle
contains substances, which is harmful to an environment. Such a
vaporous fuel should therefore not be discharged into the
atmosphere without being subjected to a specific treatment. There
has conventionally been taken a countermeasure of provision of a
canister receiving adsorbent such as an activated carbon or the
like and connected to a generation route of the vaporous fuel so as
to remove the toxic substances from the vaporous fuel by means of
the canister to obtain a clean air and then to discharge the thus
obtained clean air into the atmosphere.
5. The vaporous fuel is not always introduced into the
above-mentioned canister. When the pressure of the fuel tank
becomes for example negative, the canister sucks in air. The sucked
air and substances adsorbed by the adsorbent are mixed and then
returned to a fuel system. When the air sucked by the canister
contains foreign matters, the foreign matters may be accumulated in
the canister, thus deteriorating its performance. In view of these
problems, a filter apparatus is connected to the outlet portion of
the canister, which communicates with the atmosphere.
6. As the filter apparatus for a canister, there has conventionally
been used a filter apparatus as shown in FIG. 8. The filter
apparatus 1 is provided with a housing 2 made of synthetic resin, a
filter element 3 received in the housing 2 and a one-way valve 4
for opening or closing a passage, which can bypass the filter
element 3. Air discharged from the canister (not shown) is
introduced into a connection-opening portion 2a of the housing 2.
Fluid introduced into the connection opening portion 2a opens the
one-way valve 4 to enter a valve chamber 2b. The fluid in the valve
chamber 2b is then discharged through an element chamber 2d and an
atmospheric release-opening portion 2e into the atmosphere. When
the pressure at the side of the canister becomes negative, air is
sucked from the atmospheric release-opening portion 2e of the
housing 2 into the element chamber 2d. The thus sucked air is
filtered through the filter element 3 and then introduced into the
canister through the connection-opening portion 2a.
7. According to the above-described filter apparatus 1, the air
discharged from the canister bypasses the filter element 3 and
discharges into the atmosphere, thus leading to the maintenance of
a small exhaust resistance. The air sucked into the canister is
securely filtered through the filter element 3 on the other
hand.
8. However, in the conventional filter apparatus 1 described above,
the passage for discharging the fluid supplied from the canister
and the passage for the air filtered through the filter element 3
are separated from each other at the region of the connection
opening portion 2a. Such a structure requires the other valve
chamber 2b provided other than the element chamber 2d, resulting in
a complicated structure of the housing 2 and leading to increase in
number of components. As a result, there take place an unavoidable
increase in time and effort spent on manufacturing processes and
assembling processes of the apparatus as well as an unavoidable
increase in manufacturing costs due to the former.
SUMMARY OF THE INVENTION
9. An object of the present invention is therefore to provide a
filter apparatus for a canister, which makes it possible to
simplify the structure so as to decrease the number of
components.
10. The present invention will be described below. Reference
numerals appearing in the accompanying drawings will be given to
the following description with parentheses for facilitating the
understanding of the present invention. The present invention is
not however limited only to embodiments illustrated in the
drawings.
11. The aforementioned object can be attained by a filter apparatus
(20A, 20B, 40A, 40B) for a canister of the present invention
defined in claim 1, which is to be connected to an outlet portion
(17c) of the canister (12) mounted on a fuel supply system (10) for
a vehicle and comprises:
12. a housing (21, 41) having a connection opening portion (25,
45), which is to be connected to said outlet portion and an
atmospheric release opening portion (26, 46) communicating with an
atmosphere;
13. a filter element (30, 50) received in said housing;
14. wherein:
15. said filter element is provided with a filter body (31, 51)
having a filtering function and with a partition (32, 52), which
divides, in cooperation with said filter body, an inside of said
housing into a clean-side zone (S1) communicating with said
connection opening portion and a dirty-side zone (S2) communicating
with said atmospheric release opening portion; and
16. said partition is provided with a one-way valve (33, 53), which
permits fluid to pass from said clean-side zone to said dirty-side
zone and prevents said fluid from passing from said dirty-side zone
to said clean-side zone.
17. According to the present invention, the one-way valve (33, 53)
is mounted on the filter element (30, 50), and it is accordingly
unnecessary to provide the inside of the housing with any chamber
for the one-way valve other than a filter element-receiving
chamber. As a result, the shape of the housing can be simplified so
as to decrease in number of components. It is therefore possible to
decrease time and effort spent on manufacturing processes and
assembling processes of the apparatus and reduce the manufacturing
cost.
18. In the filter apparatus defined in claim 1, the filter body may
be formed into a hollow cylindrical shape or a flat plate shape.
When the filter body having the hollow cylindrical shape is used,
there may be adopted a structure defined in claim 2, in which one
end of the filter body is joined to an inner wall of the housing so
that a hollow portion (31a) of the filter body is connected to the
connection opening portion (25) from the inside of the housing
(21); the partition (32) is disposed at a side of the other end of
the filter body; and there is provided the one-way valve (33),
which permits the fluid introduced to a side of the other end of
the hollow portion to pass therethrough and prevents the fluid from
flowing into the hollow portion. When the filter body having the
flat plate shape is used, there may be adopted a structure defined
in claim 3, in which the partition is joined to the filter body so
as to surround the outer periphery of the filter body; and the
partition is joined over its entire periphery to the inner wall of
the housing.
19. The aforementioned object can also be attained by a filter
apparatus (20A, 20B) for a canister of the present invention
defined in claim 4, which is to be connected to an outlet portion
(17c) of the canister (12) mounted on a fuel supply system (10) for
a vehicle and comprises:
20. a housing (21) having a connection opening portion (25), which
is to be connected to said outlet portion and an atmospheric
release opening portion (26) communicating with an atmosphere;
21. a filter element (30) received in said housing so that a hollow
portion (31a) passing through a center of a filter body (31) of
said filter element is connected to said connection opening portion
from the inside of said housing at one end of said hollow
portion;
22. wherein:
23. said hollow portion of said filter element is utilized as a
part of a passage for introducing fluid, which has been introduced
from said canister into said connection opening portion, into said
atmospheric release opening portion; and
24. there is provided at an other end of said hollow portion a
one-way valve (33), which permits the fluid to discharge from a
side of said other end of said hollow portion and prevents the
fluid from flowing from the side of said other end into said hollow
portion.
25. According to the present invention, the fluid discharged from
the canister (12) is introduced through the hollow portion (31a) of
the filter element into the atmospheric release opening portion
(26), and it is accordingly unnecessary to separate, at the
connection opening portion (25), the passage for the fluid
discharged from the canister and the passage for the air, which has
been filtered by means of the filter element from each other. The
one-way valve (33) can be provided at the other end of the hollow
portion of the filter element, with the result that the filter
element and the one-way valve can be received in the common chamber
in the housing (21). The shape of the housing of the filter
apparatus (20A, 20B) can accordingly be simplified so as to
decrease in number of components. It is therefore possible to
decrease time and effort spent on manufacturing processes and
assembling processes of the apparatus and reduce the manufacturing
cost.
26. In the filter apparatus defined in claim 4, there may be
adopted a structure defined in claim 5, in which an end plate (32)
is secured to the end of the filter body (31) of the filter element
(30) and the one-way valve (33) is secured to the end plate. In
this case, with respect to the shape of the housing (21), a simple
vessel, which can receive the filter element (30) suffices.
27. The one-way valve (33) may have a structure defined in claim 6,
in which the one-way valve can come into close contact with a valve
seat (32b) by its own weight to close the hollow portion (31a) or
can be apart from the valve seat under a function of pressure of
the fluid introduced into the hollow portion. In this case, the
pressure of the fluid introduced from the canister (12) into the
hollow portion (31a) of the filter element (30) causes the one-way
valve (33) to open, thus making it possible to discharge the fluid
so as to bypass the filter body (31). In case that the suction of
air takes place in the canister, the pressure of the hollow portion
of the filter element becomes negative so that the one-way valve
comes into close contact with the valve seat (32b). Utilization of
the negative pressure applied to the hollow portion of the filter
element causes the one-way valve to close, and no power is
therefore required for operating the one-way valve, thus obtaining
the more simplified structure of the filter apparatus (20A, 20B).
The negative pressure applied to the hollow portion becomes larger,
according as airflow resistance in the filter body increases after
a lapse of time. It is therefore possible to securely close the
one-way valve when introducing the air into the side of the
canister.
28. The aforementioned object can also be attained by a filter
apparatus (40a, 40b) for a canister of the present invention
defined in claim 7, which is to be connected to an outlet portion
(17c) of the canister (12) mounted on a fuel supply system (10) for
a vehicle, comprises:
29. a housing (41) having a connection opening portion (45), which
is to be connected to said outlet portion and an atmospheric
release opening portion (46) communicating with an atmosphere;
30. a filter element (50) received in said housing;
31. wherein:
32. said filter element is provided with a filter body (51), which
has a filtering function and a flat plate shape and with a
partition (52) connected to said filter body so as to surround said
filter body;
33. said partition is joined over its entire periphery to an inner
wall of said housing so as to divide an inside of said housing into
a clean-side zone (S1) communicating with said connection opening
portion and a dirty-side zone (S2) communicating with said
atmospheric release opening portion; and
34. said partition is provided with a one-way valve (53), which
permits fluid to pass from said clean-side zone to said dirty-side
zone and prevents said fluid from passing from said dirty-side zone
to said clean-side zone.
35. In the present invention defined in claim 7, the filter element
(50) is provided with the one-way valve (53) in the same manner as
the present inventions defined in claims 1 and 4, and the shape of
the housing can accordingly be simplified so as to decrease in
number of components. It is therefore possible to decrease time and
effort spent on manufacturing processes and assembling processes of
the apparatus and reduce the manufacturing cost. The filter body
(51) formed into a flat plate shape permits to decrease the height
of the housing in the thickness direction (i.e., in the vertical
direction of FIG. 5) of the filter body (51)
36. In the filter apparatus defined in claim 7, there may be
adopted a structure defined in claim 8, in which the partition (52)
is provided with a tubular member (52c), which connects the
clean-side zone (S1) with the dirty-side zone (S2);
37. the tubular member is provided on its forward end portion with
a valve seat (52d), which extends in a perpendicular direction when
the filter apparatus is kept in its used condition; and
38. the one-way valve (53) has a structure in which the one-way
valve can come into close contact with the valve seat by its own
weight to close the tubular member or can be apart from the valve
seat under a function of pressure of the fluid introduced from the
connection opening portion into the clean-side zone.
39. In this case, no power is required for operating the one-way
valve (53) in the same manner as the present invention defined in
claim 6, thus obtaining the more simplified structure of the filter
apparatus (40A, 40B). The negative pressure applied to the hollow
portion becomes larger, according as airflow resistance in the
filter body increases after a lapse of time. It is possible to
securely close the one-way valve when introducing the air into the
side of the canister.
BRIEF DESCRIPTION OF THE DRAWINGS
40. FIG. 1 is a vertical sectional view illustrating a filter
apparatus for a canister of the first embodiment of the present
invention;
41. FIG. 2 is a schematic view illustrating a fuel supply system
into which the filter apparatus for a canister as shown in FIG. 1
is built;
42. FIG. 3 is a vertical sectional view illustrating a filter
apparatus for a canister of the second embodiment of the present
invention;
43. FIG. 4 is a horizontal sectional view illustrating a filter
apparatus for a canister of the third embodiment of the present
invention;
44. FIG. 5 is a vertical sectional view illustrating the filter
apparatus as shown in FIG. 4;
45. FIG. 6 is a horizontal sectional view illustrating a filter
apparatus for a canister of the fourth embodiment of the present
invention;
46. FIG. 7 is a vertical sectional view illustrating the filter
apparatus as shown in FIG. 6; and
47. FIG. 8 is a vertical sectional view illustrating the
conventional filter apparatus for a canister.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
48. Now, embodiments of a filter apparatus for a canister of the
present invention will be described in detail below with reference
to the accompanying drawings.
49. FIG. 2 illustrates essential parts of a fuel supply system for
a vehicle, into which a filter apparatus for a canister of the
first embodiment of the present invention is built. The fuel supply
system 10 is provided with a canister 12 connected to a fuel tank
11, and with a filter apparatus 20A connected to the canister 12.
The canister 12 has a housing 13, a pair of upper and lower
partitions 14a, 14b disposed in the inside of the housing 13, and
adsorbent such as an activated carbon, with which the space between
the upper and lower partitions 14a, 14b is filled. Each of the
partitions 14a, 14b is formed by placing a filter layer made of
felt on a grid plate having a plurality of small apertures. The
lower partition 14b is movable upward and downward in the housing
13. Force, which is given by springs 16a, 16b and have a function
of moving upward the lower partition 14b is applied thereto. The
housing 13 is provided in its inside with a separating wall 13a,
which divides the adsorbent 15 into right and left-hand adsorbents
15a, 15b.
50. The housing 13 is provided at its upper portion with first and
second inlet portions 17a, 17b, an outlet portion 17c and a
purge-opening portion 17d. Both the inlet portions 17a, 17b are
connected to the fuel tank 11 of the vehicle. The second inlet
portion 17b is connected through a valve 18 to the fuel tank 11.
The valve 18 can be opened when a large amount of vaporous fuel is
generated, and fuel is supplied for example to the fuel tank 11.
The valve 18 kept under an opening condition causes both the inlet
portions 17a, 17b to communicate with the fuel tank 11. The valve
18 kept under a closing condition causes only the inlet portion 17a
to communicate with the fuel tank 11 on the other hand.
51. The vapor sucked from the fuel tank 11 through the inlet
portions 17a, 17b passes through the left-hand adsorbent 15a at the
left-hand side of the separating wall 13a to move below the
partition 14b. The vapor moving below the partition 14b is
introduced through a portion below the separating wall 13a into the
right-hand adsorbent 15b. Air, which has passed the adsorbent 15b
is discharged through the filter apparatus 20A into the atmosphere
from the outlet portion 17c. When the pressure of the fuel tank 11
decreases under a prescribed pressure value, the pressure in the
canister 12 becomes negative so that air is introduced through the
filter apparatus 20A into the canister 12 from the outlet portion
17c. An inlet pressure at a throttle valve 19 provided in an inlet
system of an internal combustion engine is applied to the purge
opening portion 17d. Vapor containing fuel contents is sucked from
the purge-opening portion 17d into the throttle valve 19 in
accordance with the above-mentioned inlet pressure.
52. FIG. 1 illustrates the filter apparatus 20A in detail. The
filter apparatus 20A is composed of a housing 21 and a filter
element 30 received in the housing 21. The housing 21 is obtained
by heat bonding a pair of pieces at their connection flanges 22a,
23a to each other, which pieces are formed of synthetic resin by an
injection molding method. The housing 21 is formed into a
cylindrical shape having a central line, which is identical with
the axial line CL extending in the vertical direction in FIG. 1.
The shape of the housing 21 may however be modified. The housing 21
is provided with one end wall 21a, which has a connection opening
portion 25 formed on the central portion of the end wall 21a. The
connection-opening portion 25 is connected with the outlet portion
17c of the canister 12 (see FIG. 2). The connection-opening portion
25 is formed into a tubular shape, which projects upward and
downward from the end wall 21a. The end wall 21a has on its inner
surface (i.e., its under surface as shown in FIG. 1) a ring-shape
projection 21b, which is concentric with the connection opening
portion 25. The housing 21 is provided with the other end wall 21c
on which an atmospheric release-opening portion 26 having a tubular
shape is formed.
53. The filter element 30 is composed of a filter body 31 formed of
filter paper or the like and of an end plate 32, which is secured
to the lower end surface of the filter body 31 and serves as a
partition. The filter body 31 is formed into a cylindrical shape,
which has in its center a hollow portion 31a. The upper end side of
the filter body 31 is fitted into the inside of the ring-shape
projection 21b of the end wall 21a of the housing 21. Under such a
fitting condition, the hollow portion 31a is connected to the
connection-opening portion 25 from the inner side of the housing
21. The filter body 31 and the end plate 32 divide the inside of
the housing 21 into a clean-side zone S1 communicating with the
connection opening portion 25 and a dirty-side zone S2
communicating with the atmospheric release opening 26. The filter
body may be fixed to the ring-shaped projection 21b by means of a
fastening means such as an adhesive agent so as to prevent the
filter element 30 from coming down in the housing 21.
54. The end plate 32 is provided with a tubular member 32a, which
communicates with the hollow portion 31a. The tubular member 32a
has its lower end portion, which bends in the horizontal direction.
The end surface (i.e., a valve seat) 32b of the tubular member 32a
is substantially identical with a perpendicular plane. A one-way
valve 33 is mounted on the end plate 32 so as to swingable around a
hinge shaft 33a. The one-way valve 33 comes into close contact with
the above-mentioned end surface 32a on condition that it is hanged
from the hinge shaft 33a in the perpendicular direction by its own
weight. The end plate 32 may be formed integrally with the filter
body 31 by carrying out, for example, an injection molding method
in which the filter body 31 is used as an insert member.
55. In the above-described filter apparatus 20A, air that is
discharged from the outlet portion 17c of the canister 12 into the
filter apparatus 20A is introduced from the hollow portion 31a of
the filter element 30 into the tubular member 32a as indicated in
FIG. 1 in the form of arrow "F out". The pressure of the thus
introduced air causes the one-way valve 33 to apart from the end
surface 32b so as to permit release of the air into the atmosphere
from the atmospheric release opening portion 26.
56. When the pressure of the canister 12 becomes negative so that
air is sucked into the canister from the outlet portion 17c, on the
other hand, the resultant suction force causes the one-way valve 33
to come into close contact with the end surface 32b of the tubular
member 32a. Air that is sucked into the housing 21 from the
atmospheric release opening portion 26 passes through the filter
body 31 as indicated in FIG. 1 in the form of arrow "F in" and is
then sucked into the canister 12 through the hollow portion 31a and
the connection opening portion 25. According as air-flow resistance
in the filter body 31 of the filter element 30 increases after a
lapse of time, the negative pressure applied to the hollow portion
31a becomes larger, resulting in increase in force having the
function of closing the one-way valve 33. It is therefore possible
to carry out a secure and proper filtration of air sucked into the
canister 12 from the filter apparatus 20A, even when there is
adopted a simple structure in which the one-way valve 33 is hanged
from the hinge shaft 33a so as to be able to come, by its own
weight, into close contact with the end surface 32b of the tubular
member 32a, which serves as the valve seat. In addition, there is
required no power source such as a spring for urging the one-way
valve 33 against the end surface 32b. There is a small resistance
upon opening the one-way valve 33, thus making it possible to
discharge smoothly air introduced from the canister 12.
57. In the first embodiment of the present invention described
above, the one-way valve 33 may be disposed above the filter
element 30. In the first embodiment as shown in FIG. 1, the filter
apparatus 20A is described as being mounted on the vehicle in a
vertical posture in which the axial line of the hollow portion 31a
of the filter element 30 is substantially identical with the
vertical line. The present invention may also be applied to a
filter apparatus 20B, which is to be mounted on the vehicle in a
horizontal posture as shown in FIG. 3, in which the axial line of
the hollow portion 31a of the filter element 30 is substantially
identical with the horizontal line. In this case, the tubular
member 32a is omitted, the one-way valve 33 is disposed on a plane,
which is substantially identical with the surface 32c of the end
plate 32, which serves as the valve seat for the one-way valve 33.
Places of the filter apparatus 26, on which the connection opening
portion 25 and the atmospheric release opening portion 26 should be
formed are not limited to ones described in the first embodiment,
and they may be formed on any places of the housing, other than the
end portions in the longitudinal direction thereof.
58. FIGS. 4 and 5 illustrate a filter apparatus for a canister of
the second embodiment of the present invention. The filter
apparatus 40A is composed of a housing 41 and a filter element 50
received in the housing 41. The housing is formed of synthetic
resin into a rectangular parallelepiped vessel by an injection
molding method or the like. the housing 41 has in its central
portion in the thickness direction (i.e., in the vertical direction
in FIG. 5) a groove portion 44 formed over the entire periphery of
the inner surface of the housing 41. The housing 41 is provided
with one end wall 41, which is located on one side in the
longitudinal direction of the housing 41 and has a connection
opening portion 45 connected to the outlet portion 17c of the
canister 12 (see FIG. 2) and with the other end wall 41b, which is
located on the other side in the same direction and has an
atmospheric release opening portion 46 having a tubular shape. The
connection-opening portion 45 is located above the groove portion
44 and the atmospheric release-opening portion 46 is located below
the groove portion 44.
59. The filter element 50 is composed of a filter body 51 formed of
filter paper, which is pleated into an external form of flat plate,
and a frame 52 joined to the filter body 51 so as to surround the
periphery of the filter body 51. The frame 52 is formed integrally
with the filter body 51 by carrying out, for example, an injection
molding method in which the filter body 51 is used as an insert
member. The frame 52 has a flange 52a formed on the outer periphery
of the frame 52 over the entirety thereof. The peripheral portion
of the flange 52a is fitted into the groove 44 of the housing 41 so
that the inside of the housing 41 is divided into a clean-side zone
S1 communicating with the connection opening portion 45 and a
dirty-side zone S2 communicating with the atmospheric release
opening 46.
60. The flange 52a has a through-hole 52b formed thereon, which
connects the both zones S1, S2 with each other. The through-hole
52b can be opened and closed by means of a one-way valve 53 mounted
on the flange 52a. The one-way valve 53 is composed of a valve
retainer 53a, a valve element 53b and a compression spring 53c. The
valve retainer 53a has a tubular shape with a bottom and is joined
to the flange 52a in the dirty-side zone S2 so as to be concentric
with the through-hole 52b. The valve element 53b is received in the
valve retainer 53a. The compression spring 53c is located between
the valve element 53b and the valve retainer 53a so as to press the
valve element 53b against the flange 52a to close the through-hole
52b.
61. In the above-described filter apparatus 40A, when air is
discharged from the outlet portion 17c of the canister 12 into the
filter apparatus 40A and the pressure of the clean-side zone S1
exceeds the pressure of the dirty-side zone S2 by a prescribed
value, then the valve element 53b is apart from the through-hole
52b against the function of the spring 53c so that the air flows
from the clean-side zone S1 into the dirty-side zone S2 through the
through-hole 52b and vent holes 53d formed on the side wall of the
valve retainer 53a. The air discharged from the canister 12 is
therefore discharged into the atmosphere through the atmospheric
release-opening portion 46 without passing through the filter body
51.
62. When the pressure of the canister 12 becomes negative so that
air is sucked from the outlet portion 17c into the canister 12, the
resultant suction force and the force given by the spring 53c cause
the valve element 53b of the one-way valve 53 to come into close
contact with the flange 52a so as to close the through-hole 52b.
Accordingly, the air that has been sucked from the atmospheric
release opening portion 46 into the housing 41 passes through the
filter body 51 and is then sucked into the canister 12.
63. Also in the second embodiment described above, according as
air-flow resistance in the filter body 51 increases after a lapse
of time, the negative pressure applied to the clean-side zone S1
becomes larger, resulting in increase in force having the function
of closing the through-hole 52b with the valve element 53b of the
one-way valve 53.
64. FIGS. 6 and 7 illustrate a filter apparatus for a canister of
the third embodiment of the present invention. The filter apparatus
40B is identical with the filter apparatus 40A as shown in FIGS. 4
and 5 except that the one-way valve is changed to the same one as
that shown in FIG. 1. More specifically, the flange 52a is provided
with a tubular member 52c, which projects toward the side of the
dirty side zone S2. The lower end portion of the tubular member 52c
bends in the horizontal direction. The end surface (i.e., a valve
seat) 52d of the tubular member 52c is substantially identical with
a perpendicular plane. A valve element 53e of a one-way valve 53 is
mounted on the end surface 52d so as to be able to come into close
contact therewith. The valve element 53e comes into close contact
with the above-mentioned end surface 52d on condition that it is
hanged from a hinge shaft 53f in the perpendicular direction by its
own weight. The filter apparatus 40B is mounted on a vehicle in a
posture in which the axial line of the filter body 51 is
substantially identical with the horizontal line.
65. Also in the above-described third embodiment, air that has been
introduced from the canister 12 into the clean-side zone S1 passes
through the one-way valve 53 without passing through the filter
body 51 and is then discharged into the atmosphere through the
atmospheric release opening portion 46. When the pressure of the
canister 12 becomes negative, the valve element 53e of the one-way
valve 53 comes into close contact with the end surface 52d of the
tubular member 52c so that the air flowing into the dirty-side zone
S2 passes through the filter body 51 and is then sucked from the
clean-side zone S1 into the canister 12.
66. The present invention is not limited only to the
above-described embodiments and can be worked in the form of the
other embodiments. For example, the filter body 31, 51 is not
limited only to one formed of a pleated filter paper. The end plate
32 and the frame 52, which serve as the partition may be connected
to the filter bodies 31 and 51 by the conventional connecting means
such as bonding by adhesive agent, heat-bonding or the like,
respectively, other than the formation of the integral body of the
former with the latter by the insert forming method.
67. According to the present invention as described in detail,
since the inside of the housing is divided into the clean-side zone
and the dirty-side zone by the filter element, which is provided
with the one-way valve, the shape of the housing can be simplified
so as to decrease in number of components. It is therefore possible
to decrease time and effort spent on manufacturing processes and
assembling processes of the apparatus and reduce the manufacturing
cost. When there is adopted a structure that the one-way valve can
come into close contact with the valve seat by its own weight to
close the hollow portion and can be away from the valve seat under
the function of pressure of the fluid given in the hollow portion,
then no power is required for operating the one-way valve, thus
leading to the more simplified structure of the filter apparatus.
Especially, force having the function of closing the one-way valve
increases, according as airflow resistance in the filter body of
the filter element increases after a lapse of time. It is therefore
possible to carry out a secure and proper filtration of air sucked
into the canister from the filter apparatus, thus improving
reliability of the filter apparatus.
* * * * *