U.S. patent application number 09/795978 was filed with the patent office on 2001-10-25 for integrally molded type filter unit and manufacture of the same.
Invention is credited to Akiyama, Mitsuhiko, Goto, Sadahito, Minemura, Shinichi.
Application Number | 20010032545 09/795978 |
Document ID | / |
Family ID | 18577526 |
Filed Date | 2001-10-25 |
United States Patent
Application |
20010032545 |
Kind Code |
A1 |
Goto, Sadahito ; et
al. |
October 25, 2001 |
Integrally molded type filter unit and manufacture of the same
Abstract
A filter unit comprising a filter part made of an
adsorbent-bearing filtration material and characterized in that
said filter part is integrally molded with a filter holding frame
made of a thermoplastic resin and that said adsorbent of said
filter part is packed to the position contacting the filter holding
frame.
Inventors: |
Goto, Sadahito; (Ohtsu-shi,
JP) ; Akiyama, Mitsuhiko; (Osaka, JP) ;
Minemura, Shinichi; (Ohtsu-shi, JP) |
Correspondence
Address: |
Stephen B. Maebius
FOLEY & LARDNER
Washington Harbour
3000 K Street, N.W., Suite 500
Washington
DC
20007-5109
US
|
Family ID: |
18577526 |
Appl. No.: |
09/795978 |
Filed: |
March 1, 2001 |
Current U.S.
Class: |
96/134 ; 55/497;
55/502; 55/521; 55/524 |
Current CPC
Class: |
Y10S 55/05 20130101;
B01D 46/0001 20130101; B29L 2031/14 20130101; B29C 45/14336
20130101; Y10S 264/48 20130101; B01D 46/521 20130101; B01D 2253/102
20130101; B29L 2016/00 20130101 |
Class at
Publication: |
96/134 ; 55/497;
55/502; 55/521; 55/524 |
International
Class: |
B01D 053/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 2, 2000 |
JP |
2000-56616 |
Claims
What is claimed is:
1. A filter unit comprising a filter part made of an
adsorbent-bearing filtration material and characterized in that
said filter part is integrally molded with a filter holding frame
made of a thermoplastic resin and that said adsorbent of said
filter part is packed to the position contacting the filter holding
frame.
2. The filter unit according to claim 1, characterized in that said
filter holding frame has ribs in the side faces in the filtration
material arrangement direction.
3. The filter unit according to claim 2, characterized in that the
width of said ribs is 10 to 90% to the width of each side face of
said filter holding frame in the filtration material arrangement
direction and the thickness of said ribs is 10 to 70% to the
thickness of each side face in the filtration material arrangement
direction.
4. The filter unit according to claim 1, characterized in that said
filter holding frame has 3 or more gates in the side faces in the
filtration material arrangement direction.
5. The filter unit according to claim 1, characterized in that said
thermoplastic resin is an olefin type thermoplastic resin
elastomer.
6. The filter unit according to claim 1, characterized in that said
filter holding frame has 1% or higher torsion defined as the
following equation: torsion=[(L)/(W)].times.100% [wherein, (L)
denotes the distance in which the filter holding frame is moved
owing to the strain when force is applied to the filtration
material face in one end of the filter holding frame in the
vertical direction while a side face in the opposed other end of
the holding frame being fixed in the filtration material width
direction; and (W) denotes the width of the holding frame.].
7. A filter unit comprising a filter part made of a filtration
material and characterized in that said filter part is integrally
molded with a filter holding frame made of a thermoplastic resin
and that said filter holding frame has 1% or higher torsion defined
as the following equation: torsion=[(L)/(W)].times.100% [wherein,
(L) denotes the distance in which the filter holding frame is moved
owing to the strain when force is applied to the filtration
material face in one end of the filter holding frame in the
vertical direction while a side face in the opposed other end of
the holding frame being fixed in the filtration material width
direction; and (W) denotes the width of the holding frame.].
8. The filter unit according to claim 7, characterized in that the
thickness of said filter holding frame is 2 mm or thinner and said
torsion is 25 to 150%.
9. The filter unit according to claim 7, characterized in that said
filter holding frame has ribs in the side faces in the filtration
material arrangement direction.
10. The filter unit according to claim 9, characterized in that the
width of said ribs is 10 to 90% to the width of each side face of
said filter holding frame in the filtration material arrangement
direction and the thickness of said ribs is 10 to 70% to the
thickness of each side face in the filtration material arrangement
direction.
11. The filter unit according to claim 7, characterized in that
said filter holding frame has 3 or more gates in the side faces in
the filtration material arrangement direction.
12. The filter unit according to claim 7, characterized in that
said thermoplastic resin is an olefin type thermoplastic resin
elastomer.
13. A method for manufacturing a filter unit comprising a process
of installing a filter part made of an adsorbent-bearing a
filtration material in the inside of dies and a process of forming
a filter holding frame integrally with said filter part by pouring
a thermoplastic resin to the inside of said dies in which said
filter part is installed and characterized in that the clearance A
of an escape part in said dies is controlled to be 80 to 115% to
the thickness of said filtration material, the clearance B in a
grip part is controlled to be 25 to 45% to the thickness of said
filtration material, and the distance C of said grip part is
controlled to be 0.5 to 5 mm.
14. The method for manufacturing a filter unit according to claim
13, characterized in that the process of integrally forming said
filter part and said filter holding frame is carried out by
simultaneous joining by an injection molding method.
15. The method for manufacturing a filter unit according to claim
13, characterized in that ribs are formed in the side faces of said
filter holding frame in the filtration material arrangement
direction.
16. The method for manufacturing a filter unit according to claim
13, characterized in that the width of said ribs is controlled to
be 10 to 90% to the width of each side face of said filter holding
frame in the filtration material arrangement direction and the
thickness of said ribs is controlled to be 10 to 70% to the
thickness of each side face in the filtration material arrangement
direction.
17. The method for manufacturing a filter unit according to claim
13, characterized in that 3 or more gates are formed in the side
faces of said filter holding frame in the filtration material width
direction.
18. The method for manufacturing a filter unit according to claim
13, characterized in that the thickness of said filter holding
frame is controlled to be 2 mm or thinner.
19. The method for manufacturing a filter unit according to claim
13, characterized in that said thermoplastic resin is an olefin
type thermoplastic elastomer.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an integrally molded type
filter unit and a method for manufacturing the filter unit, more
particularly to a filter unit possible to be produced by joining a
filter holding frame to a separately produced filter part
simultaneously with injection molding of the frame, installation
easiness to be installed in a gas treatment apparatus, light weight
and having low pressure loss and high dust collecting efficiency
and to a manufacturing technique of the filter unit.
[0003] 2. Description of the Related Art
[0004] Recently, the demand for a gas treatment apparatus such as
an air purifier, an air conditioner equipped with such an air
purifier, and the like has been increasing.
[0005] The gas treatment apparatus usually contains a filter for
removing airborne dust and malodorous components. Such a filter is
used as a filter unit comprising a filter part made of activated
carbon-containing paper, polyester nonwoven cloths, glass fiber
paper and formed in a sheet-like form or processed in a pleated
form and a filter holding frame to which the filter part is
attached. The filter unit is required to be easy for installation
in a gas treatment apparatus.
[0006] Conventionally, in the case of manufacturing such a filter
unit, a filter part previously processed to be a sheet-like shape
or a pleated shape is made ready, built in a filter holding frame
separately made ready and then fixed in the filter holding frame by
methods, for example, by using an adhesive, engagement claws and
screws, or springs. Consequently, there occurs a problem that the
number of processes is high and the manufacturing efficiency is
decreased.
[0007] Today, the following methods have been made known: as
disclosed in Japanese Patent Unexamined Publication (Kokai) No.
10-263348, a method of integrally forming a filter unit using a
packing in the circumference of a filter holding frame and as
disclosed in Japanese Patent Unexamined Publication (Kokai) No.
11-90150, a method of using a foamed resin for a filter holding
frame.
[0008] However, the methods aim at mainly improving the production
efficiency but pay no attention to improvement of properties such
as the strength and the weight of a filter unit itself and the
capability and the characteristic as a filter.
[0009] An integrally molding method wherein a filter part made
ready in a separated process is stuck to a filter holding frame
simultaneously with the molding of the filter holding frame can be
considered as a method for manufacturing a filter unit with a high
strength and light weight at high manufacturing efficiency.
[0010] However, the integrally molding method also has a problem
especially in the case where an adsorbent of such as an activated
carbon is contained in a filter part. That is, the surface area of
a filter part is widened to improve the function of an adsorbent
even a little more, the joining part to a holding frame is lessened
as much as possible to improve the dust collecting efficiency, and
even the end part of a holding frame is filled with activated
carbon to improve the filter molding processibility and such
methods are considered to achieve such improvements, however these
methods may possibly lead to burr formation or a damage on dies
owing to separation of activated carbon from the end part of the
filter material to a grip of the die.
[0011] Therefore, it can be considered to prevent burr formation
and the damage of dies that no activated carbon is put in the end
part of a filter material, however it causes a problem that the
effective surface area as a filter is narrowed and the filter
capability is decreased.
[0012] Further, it can also be considered to prevent burr formation
and activated carbon separation that a resin flow-in part with a
several mm width is formed in the grip part in the inner side of
the frame by properly amending the die structure, however it causes
a problem that the effective surface area as a filter is narrowed
and the filter capability is decreased.
[0013] On the other hand, a filter holding frame for installing a
filter in a gas treatment apparatus is desired to be excellent in
handling flexibility as to be freely twisted or changed in the form
at the time of installation and is preferable to be thin and light
weight, however if the holding frame is made thin and light weight,
the strength of the frame is decreased and it results in a problem
that the frame is hard to be installed in a gas treatment
apparatus, especially in a curved one.
SUMMARY OF THE INVENTION
[0014] The present invention hence aims at providing a filter unit
having a wide effective surface area of a filtration material and
capable of providing a high dust collecting efficiency without
causing drop of the activated carbon from the end part of the
filtration material of the filter to a grip part of dies and the
present invention aims at providing a method for manufacturing such
a filter unit.
[0015] The present invention further aims at providing a filter
unit with light weight by making the thickness of the filter
holding frame thin, excellent handling flexibility at the time of
installation, a low pressure loss, and a high collecting efficiency
and providing a method for manufacturing such a filter unit
comprising an integrally molding process to simplify manufacturing
processes and to lower the fraction defective in the manufacturing
processes.
[0016] A filter unit according to the present invention is
characterized by comprising a filter part made of an
adsorbent-bearing filtration material and a filter holding frame
made of a thermoplastic resin and integrally molded with a part of
the filter part and the adsorbent of the filter part is packed to
the position contacting the filter holding frame.
[0017] With such a constitution, a filter unit with a wide
effective surface area of the filtration material and a high
collection efficiency can be provided without causing burr
formation or damages on dies owing to separation of the adsorbent,
e.g. activated carbon, from the end part of the filtration material
of the filter to a grip part of the die. Such a filter unit can be
manufactured by a method, which will be described below, developed
by inventors of the present invention.
[0018] The filter part in the present invention is a sheet-like or
sheet-pleated product produced from paper, polyester or other
polymer nonwoven cloths, glass fiber paper, porous resin sheets,
various types of fabrics and textiles containing an adsorbent such
as activated carbon, zeolites, and the like and subjected to the
integrally molding process with a filter holding frame.
[0019] The materials for the filter holding frame to be employed
for the present invention include thermoplastic resins such as
acrylic resins, phenol resins, silicon resins, polyolefin resins,
polyurethane resins, epoxy resins, polyester resins, poly(vinyl
chloride) type resins, melamine resins, poly (vinyl acetate) type
resins, polystyrene resins, and the like; thermoplastic elastomers
such as styrene type thermoplastic elastomer, urethane type
thermoplastic elastomer, olefin type thermoplastic elastomer,
polyester type thermoplastic elastomer, polyamide type
thermoplastic elastomer, vinyl chloride type thermoplastic
elastomer, fluoro type thermoplastic elastomer, and the like; and
any material which can be molded by molten injection molding.
[0020] The filter holding frame is preferable to have ribs in the
side faces in the filtration material arrangement direction and the
width of each rib is preferably 10 to 90% and more preferably 15 to
40% to the width of each side face in the filtration material
arrangement direction of the filter holding frame. The thickness of
each rib is preferably 10 to 70% and more preferably 20 to 50% to
the thickness of each side face in the filtration material
arrangement direction.
[0021] If the width of each rib is 10% or narrower to the width of
the side faces of the holding frame, sufficient strength cannot be
provided and hence it is not preferable. If the width is 90% or
wider to the width of the side faces of the holding frame, the
reinforcing effect can be provided, however it means that the side
face thickness is thickened and that the holding frame cannot be
light weight. By forming such ribs, as a practical example, in the
case where the gap (the thickness) of the side faces (in the
filtration material arrangement direction) of a filter holding
frame of dies is controlled to be 2.005 mm or narrower, preferably
1.504 mm or narrower, the thickness of the side faces of a
manufactured holding frame can be made to be 2 mm or thinner,
preferably 1.5 mm or thinner.
[0022] In such a manner, even a resin such as an olefin type
thermoplastic resin whose melt has a high viscosity can easily be
injection-molded and the thickness of the side faces (in the
filtration material arrangement direction, the width direction) of
a filter holding frame can be thin and the installation easiness
can be improved. Moreover, the degree to which the side faces (in
the filtration material arrangement direction) of the filter
holding frame is thinned can be compensated with the filter part to
result in increase of the surface area of the filter part by the
degree and consequently, the pressure loss can be lowered and the
collection efficiency can be improved. Such a thin holding frame
made of a thermoplastic resin, especially an olefin type
thermoplastic elastomer, has not been made available before.
[0023] Further, the foregoing filter holding frame is preferable to
have gates in 3 or more points in side faces in the filtration
material arrangement direction. More preferably, gates are formed
at 4 to 6 points.
[0024] Formation of the ribs and gates improves the fluidity of a
melted resin at the time of injection molding and the melted resin
is spread all over the dies within a short time and at the same
time pressure is evenly applied to the whole gap of the dies to
spread the resin without leaving any voids. As a result, a filter
part positioned in the outlet side of the dies and the melted resin
are almost perfectly brought into contact with each other without
leaving any voids. Further, since the gap of the dies can be made
narrow, the thickness of the produced filter holding frame can be
thin. To be remarkable, the hardened resin is found reinforcing the
side faces (filtration material arrangement direction) of the
filter holding frame to significantly improve the strength of the
produced filter and make the filter durable to the strain and
impact.
[0025] The foregoing thermoplastic resin is preferably an olefin
type thermoplastic elastomer. That is because the elastomer is
especially excellent in impact durability and it is desirable.
[0026] A conventional method aims at improving the productivity by
simplifying the processes and dies for filter holding frames are
only for pouring a melted resin to the gap part of the dies,
whereas the present invention provides a method developed based on
investigation of the structure of dies to easily carry out
injection molding of even a resin such as an olefin type
thermoplastic elastomer whose melt viscosity is high, to thin the
thickness of the side faces (in the filtration material arrangement
direction and the width direction) of a filter holding frame, and
to improve the installation easiness. Further, the degree to which
the side faces (in the filtration material arrangement direction)
of the filter holding frame is thinned can be compensated with the
increase of a part of the filter and as a result, the pressure loss
can be lowered and the collection efficiency can be improved.
[0027] Before, it has been said impossible to make a resin such as
an olefin type thermoplastic elastomer, whose melt viscosity is
high, thin in the thickness of the side faces (in the filtration
material arrangement direction and the width direction) of a filter
holding frame. A melted resin poured into dies from both sides in
the filtration material width direction of the filter holding frame
joins in the center part of the side faces (in the filtration
material arrangement direction) of the filter holding frame. At
that time, if the gap of the dies equivalent to rib parts is made
thin, the short takes place at the time of the injection molding.
The term, short, means that resin is not spread all over the dies
for molding a filter holding frame and cooled and solidified while
partially leaving voids and subsequently, causes uneven strength
pattern and as a result partly defective parts are formed in the
produced holding frame in the voids. However, owing to the
formation of ribs, occurrence of the short is prevented and the
inferior product production is decreased. Moreover, the strength of
the whole body of a filter holding frame is increased and the
filter holding frame is freely deformable at the time of
installation and a problem of installation difficulty at the time
of installing a filter holding frame in a curved gas treatment
apparatus is solved. Without ribs and gates, a melted resin flows
unevenly in the dies and uneven temperature distribution pattern is
formed and subsequently cooling speed differs and an uneven
strength pattern is formed in the side face parts of the cooled and
solidified filter holding frame to result in short occurrence and
inferior product formation.
[0028] The foregoing filter holding frame is preferable to have 1%
or higher torsion defined as following equation:
torsion=[(L)/(W)].times.100%
[0029] (wherein, (L) denotes the distance in which a filter holding
frame is moved owing to the strain when force is applied to the
filtration material face in one end of the filter holding frame in
the vertical direction while a side face in the opposed other end
of the holding frame being fixed in the filtration material width
direction; and (W) denotes the width of the holding frame).
[0030] The torsion is more preferably 10% or higher and furthermore
preferably 25% of higher.
[0031] The twisting of a filter unit at the time of installing the
unit in a gas treatment apparatus means the temporal deformation
caused by the force applied to the filter unit at the time of
insertion and the degree of the deformation is defined as the
above-mentioned equation and represents the characteristic. That
is, the torsion is defined as the value calculated by dividing the
distance (L) in which a filter holding frame is moved owing to the
strain when force is applied to the filtration material face in one
end of the filter holding frame in the vertical direction while a
side face in the opposed other end of the holding frame being fixed
in the filtration material width direction with the width of the
holding frame (W) and multiplying the obtained value by 100.
[0032] The smaller the torsion is, the tougher the holding frame is
and the harder the holding frame is deformed and it means that
installation in a curved gas treatment apparatus become more
difficult. The torsion is sufficient to be at least 1% and in the
case of 10% or higher, preferably 25% or higher, there is no
trouble at the time of installation in a curved treatment
apparatus.
[0033] The method for manufacturing a filter unit according to the
present invention comprises a process of setting a filter part made
of an adsorbent-bearing filtration material in dies, a process of
pouring a thermoplastic resin in the dies in which the filter part
is set and forming a filter holding frame integrally with the
foregoing filter part.
[0034] The clearance A of an escape part in the foregoing dies is
controlled to be 80 to 115% to the thickness of the foregoing
filtration material, the clearance B in the grip part is controlled
to be 25 to 45% to the thickness of the foregoing filtration
material, and the distance C of the foregoing grip part is
controlled to be 0.5 to 5 mm.
[0035] By controlling the clearance A of the escape part is
controlled to be 80 to 115%, preferably 100 to 110%, the clearance
B in the grip part is controlled to be 25 to 45%, preferably 35 to
40%, and the distance C of the grip part is controlled to be 0.5 to
5 mm, preferably 1 to 3 mm, the present invention can keep the
surface area of the filtration material wide and provide an
excellently integrally molded filter.
[0036] In this case, the clearance means the gap between dies
sandwiching the filtration material part of the filter, that is,
the distance between the cavity side and the core side. The grip
part is positioned in the boundary of the filtration material of
the filter to the holding frame and means another filtration
material part of the filter, that is a part where the clearance is
made narrow than the escape part. By forming the grip part and the
escape part, a melted thermoplastic resin does not flow into the
filtration material part and the filtration material structure can
be formed without being damaged. Even if activated carbon is
deposited in the filter terminal parts, the filter can easily be
stuck to a holding frame by adjusting the A, B, C values and thus
the present invention is completed.
[0037] With such a constitution, when a melted resin is poured to
dies, bleeding of the melted resin to a filtration material does
not take place and the filtration material of a filter can utilized
to the utmost extent. If the clearance A is set 80% or lower, the
filtration material of the filter is possibly pressurized and
damaged and the pressure loss may be increased. If the clearance A
is set 115% or higher, the pleated form of the filter part is
possibly deformed and wrinkled. If the clearance B is set 25% or
lower, too, the filtration material of the filter is possibly
pressurized and damaged and the pressure loss may be increased. If
the clearance B is set 45% or higher, the resin possibly flows out
to the filter part and burrs may be formed. Further, if the
distance C of the grip part is set 0.5 mm or shorter, too, the
resin possibly flows out to the filter part and burrs may be formed
and if the distance C is set 5 mm or longer, the surface area of
the filter part is possibly decreased and the filtration capability
is decreased and thus these are not preferable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] FIG. 1A shows a perspective view of a filter unit
manufactured by a method of the present invention and FIG. 1B shows
a side face figure of the filter unit shown in FIG. 1A;
[0039] FIG. 2 shows a perspective view of a pleated filtration
material to be a filter part;
[0040] FIG. 3 shows the cross section figures of molding dies for
manufacturing a filter unit according to the present invention;
[0041] FIG. 4 shows a schematic plane figure of a lower die of the
molding dies shown in FIG. 3; and
[0042] FIG. 5 shows a perspective view showing the lower die of the
molding dies in which the filter part shown in FIG. 2 is
installed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] The preferred embodiments of a filter unit and its
manufacture according to the present invention will be described in
detail with reference to figures.
[0044] This integrally molded type filter unit can be produced to
be in a form shown in FIG. 1A and FIG. 1B by assembling and setting
a filter part 5, which is made ready in another process and formed
in a sheet-like shape or processed in pleated state as shown in
FIG. 2 using a nonwoven fabric containing an adsorbent such as
activated carbon, in dies for a filter holding frame as illustrated
in FIG. 3 and FIG. 4 and injection-molding a thermoplastic resin.
Simultaneously with that, the filter part and the holding frame are
joined to each other to give filter unit in the form shown in FIG.
1A and FIG. 1B.
[0045] The method for manufacturing the filter unit according to
the present invention is an integrally molding method for sticking
a filter part made of a filtration material 5 previously mad ready
in another process to a filter holding frame simultaneously with
molding of the filter holding frame. By making the thickness of the
side faces of the filter holding frame thin, the weight is made
light and the installation easiness is improved and at the same
time the surface area of the filter part is increased to the extent
by the degree to which the thickness is made thin to lower the
pressure loss and improve the collection efficiency of the
resultant filter unit. In addition to that, the present method can
simplify the manufacturing processes and lower the fraction
defective.
[0046] The filter unit whole body relevant to an embodiment of the
present invention is shown in FIG. 1 and the filter part is shown
in FIG. 2 and the dies to be employed for the integrally molding
process are shown in FIG. 3 and FIG. 4. In the FIG. 1, the
reference number 3 denotes the side face of the filter holding
frame in the filtration material arrangement direction and the
reference number 4 denotes the side face of the filter holding
frame in the filtration material width direction. The groove for
which the reference number 14 is assigned in FIG. 4 forms a rib
(the reference number 2 in FIG. 1 is assigned to: the reference
number 6 in the same FIG. 1B shows the rib width and the reference
number 7 shows the rib thickness) in the outside of the side face
(in the filtration material arrangement direction) of the
injection-molded filter frame part. The reference number 16 in the
FIG. 4 corresponds to a gate (the reference number 1 in FIG. 1 is
assigned to) positioned in the face of the filter frame part in the
filtration material width direction. Incidentally, the reference
number 10 shown in FIG. 3 and FIG. 5 denotes the serration part of
the lower die in which the sheet for the filter 5 is set in pleated
state.
[0047] The filter holding frame is composed of two upper and lower
separate dies 11, 12: an upper die in the fixed side and a lower
die in the movable side. That is, the filtration material 5 is put
between the two dies 11, 12 and the filter holding frame is
produced from a resin by injection-molding in the cavity formed
between the upper and the lower dies and simultaneously the holding
frame and the filtration material 5 are joined together. In the
case manner as that in a normal injection molding, a melted resin
flows in resin fluidizing routes 8, 13 shown in FIG. 3 and is
spread to the dies from the gates 1 in the side face in the width
direction of the pleats of the filter holding frame. The resin
introduction is carried out by introducing the resin from side
faces in both sides in the width direction of the pleated
filtration material of the filter holding frame and joined in the
center of the side faces in the filtration material arrangement
direction of the filter holding frame. At that time, owing to the
formation of the ribs and gates, the melted resin can flow quickly
and is smoothly spread to the gap all over the dies, so that the
above described short does not take place. In general, the flow-in
of the melted resin to the dies is completed within 15 to 20
seconds. After that, it takes 30 to 35 second to cool the inside of
the dies. After the cooling, the dies 11, 12 are separated up and
down to obtain an aiming filter unit. The reference number 9 in
FIG. 3 shows the joined figure of the upper and the lower dies
[0048] Further, the schematic figure of the dies for fixing the
filtration material 5 and forming the holding frame is shown in
FIG. 5. The clearance A of an escape part is controlled to be 80 to
115% to the thickness of the foregoing filtration material, the
clearance B in the grip part 17 is controlled to be 25 to 45%, and
the distance C of the grip part 17 is controlled to be 0.5 to 5 mm,
preferably 1 to 3 mm. Melting adhesion can perfectly be carried out
by pressure joining the cavity and the core without causing
bleeding of the melted resin for the holding frame to the
filtration material. As a result, the filtration material and the
holding frame can be joined to each other without causing
separation of the activated carbon in the filtration material and
damages on the filtration material and the activated
carbon-containing filtration material and the holding frame can
directly be joined to each other. Consequently, the effective
surface area of the activated carbon-containing filtration material
is widened and that contributes to remarkable improvement of the
filter capability.
[0049] The gap between the dies for the holding frame part can be
narrowed, that is, the thickness of the produced filter holding
frame can be made thin. To be further remarkable, the hardened
resin can reinforce the side faces (filtration material arrangement
direction) of the filter holding frame to significantly improve the
strength of the produced filter.
[0050] In the case of manufacturing a filter unit using the dies of
the embodiment of the present invention, separate production one by
one is possible, however since the occurrence of defective products
owing to the short is almost zero, the method is suitable for
continuous production and possible to improve the productivity.
Further, since the filter unit has excellent installation easiness,
the filter unit is suitable to be used for vehicles, however the
use of the filter unit is not at all restricted to such a purpose
and the filter unit is suitable for a wide range of use purposes
for a gas treatment apparatus.
[0051] Hereinafter, examples of integrally molded type filters of
specific embodiments of the present invention and comparative
examples will be described, however the present invention is not at
all restricted to these examples and allows any alterations and
modifications as fall within the true scope of the present
invention.
[0052] At first, the evaluation and measurement methods relevant to
the examples and the comparative examples will be described
below.
[0053] (1) The properties and capabilities of filtration materials
to be used for filter parts were evaluated by the following
tests.
[0054] [Filtration Material Thickness]
[0055] The thickness was measured by a thickness meter of a
measurement terminal of 25 mm.phi. at measurement load of 7
gf/cm.sup.2.
[0056] [Toughness]
[0057] Measured by a method according to JIS L 1096 8.19 B.
[0058] [Modulus of Compressive Elasticity]
[0059] Measured by a method according to JIS L 1096 8.18.
[0060] [Pressure Loss of Filtration Material]
[0061] The ventilation resistance of filtration materials was
measured at wind velocity of 48 cm/s.
[0062] [Toluene Removal Efficiency of Filtration Material]
[0063] The removal capability by one pass using 80 ppm of toluene
was measured. The concentration in the upstream side and in the
downstream side at wind velocity of 23 cm/s was measured using a
hydrocarbon meter made by Shimadzu Corporation. The removal
efficiency was calculated according to the following equation:
toluene removal efficiency=(downstream side concentration/upstream
side concentration).times.100 [%].
[0064] (2) The properties and capabilities of filter units were
evaluated in terms of the following items.
[0065] [Effective Surface Area of Filter Part]
[0066] The effective surface area of filtration materials of filter
parts in filter units was measured by a method according to JIS L
1096 8.18.
[0067] [Resin Use Amount]
[0068] The rein amount of polypropylene used for holding frames was
measured.
[0069] [Fraction Defective of Molding]
[0070] The fraction defective was calculated from the number of
defects (burrs, short, rupture of filtration materials, occurrence
of deformation) formed in 2000 shots of injection-molding based on
the following equation:
the fraction defective=(the number of defects/2000 shots)
.times.100 [%]
[0071] [Pressure Loss]
[0072] The ventilation resistance of filter units was measured at
flow-rate of a wind of 600 m.sup.3/hr.
EXAMPLE 1
[0073] As a filter part, an activated carbon-containing sheet
having 1.1 mm filtration material thickness, 22 to 26 kg-cm
toughness in the width direction, 45 to 50% modulus of compressive
elasticity in the thickness direction, 50% or higher toluene
removal efficiency of the filtration material, and 90 Pa or lower
filtration material pressure loss was pleated in 39 mm height of
pleats and 9 mm intervals of pleats and then cut in 105.5
filtration material width. The filtration material 5 was inserted
into the insert part, that is, the filtration material insertion
part 15, of the dies previously made ready and shown in FIG. 4. The
clearance A of the escape part in the dies was controlled to be
105% to the thickness of the filtration material, that is, 1.16 mm;
the clearance B in the grip part to be 40%, that is, 0.44 mm; and
the distance C of the grip part to be 1.5 mm. The filtration
material 5 was inserted into the dies and polypropylene resin
(produced by C & CTECH Co.) melted at 215.degree. C. was poured
to the gap between dies as shown in FIG. 4 by an injection-molding
apparatus from gates at 6 points through resin fluidizing routes 8
of the dies shown in FIG. 3 by applying pressure of 50
kgf/cm.sup.2. At that time, the injection time to the dies was 15
seconds and cooling after the injection was carried out for 35
seconds.
[0074] After that, the dies were separated up and down to take out
a filter unit. Consequently, a filter unit was obtained and the
filter unit had the filter unit outer size of 106 mm.times.222
mm.times.40 mm, the filter part size of 103 mm.times.216
mm.times.39 mm, pleat intervals of 9 mm and comprised a filter
holding frame having the holding frame thickness of 1.5 mm, the rib
thickness of 0.5 mm, and the rib width 6 mm. The properties of the
filter unit as a filter were measured.
EXAMPLE 2
[0075] The same filter part as that of Example 1 was used. The
formation method of the filter unit was also same as in Example 1
except that the dies were so constituted as to control the
clearance A of the escape part be 103% to the thickness of the
filtration material, that is, 1.13 mm; the clearance B in the grip
part to be 35%, that is, 0.39 mm; and the distance C of the grip
part to be 3 mm, that the thickness of the flowing-in part of the
dies was changed, and that the thickness of the holding frame was
changed to be 3 mm.
COMPARATIVE EXAMPLE 1
[0076] The same filter part as that of Example 1 was used. The
formation method of the filter unit was also same as in Example 1
except that the dies were so constituted as to control the
clearance A of the escape part be 100% to the thickness of the
filtration material, that is, 1.1 mm and no grid was formed.
COMPARATIVE EXAMPLE 2
[0077] The same filter part as that of Example 1 was used. The
formation method of the filter unit was also same as in Example 1
except that the dies were so constituted as to control the
clearance A of the escape part be 70% to the thickness of the
filtration material, that is, 0.77 mm; the clearance B in the grip
part to be 40%, that is, 0.44 mm; and the distance C of the grip
part to be 1.5 mm.
[0078] COMPARATIVE EXAMPLE 3
[0079] The same filter part as that of Example 1 was used. The
formation method of the filter unit was also same as in Example 1
except that the dies were so constituted as to control the
clearance A of the escape part be 130% to the thickness of the
filtration material, that is, 1.43 mm; the clearance B in the grip
part to be 40%, that is, 0.44 mm; and the distance C of the grip
part to be 1.5 mm.
COMPARATIVE EXAMPLE 4
[0080] The same filter part as that of Example 1 was used. The
formation method of the filter unit was also same as in Example 1
except that the dies were so constituted as to control the
clearance A of the escape part be 105% to the thickness of the
filtration material, that is, 1.16 mm; the clearance B in the grip
part to be 60%, that is, 0.66 mm; and the distance C of the grip
part to be 1.5 mm.
COMPARATIVE EXAMPLE 5
[0081] The same filter part as that of Example 1 was used. The
formation method of the filter unit was also same as in Example 1
except that the dies were so constituted as to control the
clearance A of the escape part be 105% to the thickness of the
filtration material, that is, 1.16 mm; the clearance B in the grip
part to be 40%, that is, 0.44 mm; and the distance C of the grip
part to be 6 mm.
[0082] The measurement results of the foregoing Examples 1, 2 and
Comparative Examples 1 to 5 were shown in Table 1.
1 TABLE 1 Effective Molding Toluene Holding Clearance Clearance
Distance surface area Resin use fraction removal frame A B C of
filter amount defective efficiency Pressure thickness [%] [%] [mm]
part [m.sup.2] [g] [%] [%] loss [Pa] [mm] Example 1 105 40 1.5
0.178 47.3 1 52 155 1.5 Example 2 103 35 3 0.178 56.8 1 51 157 3
Comparative 100 -- -- 0.183 47.3 85 52 155 3 Example 1 Comparative
70 40 1.5 0.178 47.3 2 52 201 1.5 Example 2 Comparative 130 40 1.5
0.178 47.3 76 52 192 1.5 Example 3 Comparative 105 60 1.5 0.178
47.3 88 52 160 1.5 Example 4 Comparative 105 40 6 0.178 47.3 1 47
188 1.5 Example 5
[0083] Further, the following is the description of the results of
the measurement of the properties and capabilities, e.g.
installation easiness to a gas treatment apparatus, of filter units
of the embodiments according to the present invention.
[0084] Tests were carried out for airborne dust removal efficiency
of the following filtration materials and filter units instead of
the toluene removal efficiency of filtration materials, the
torsion, and the installation easiness.
[0085] [Airborne Dust Removal Efficiency of Filtration
Material]
[0086] The dust removal efficiency by one pass was measured using
airborne dust of 0.3 .mu.m. The concentration of the airborne dust
of 0.3 .mu.m in the upstream side and in the downstream side at
wind velocity of 23 cm/s was measured using a powder dust measuring
apparatus (trade name: RION PARTICLE COUNTER KC-01C). The airborne
dust removal efficiency of a filtration material was calculated
from the results.
[0087] [Airborne Dust Removal Efficiency of Filter Unit]
[0088] The dust removal efficiency by one pass was measured using
airborne dust of 0.3 .mu.m. The concentration of the airborne dust
of 0.3 .mu.m in the upstream side and in the downstream side at
flow rate of 300 m.sup.3/hr of air was measured using a powder dust
measuring apparatus (trade name: RION PARTICLE COUNTER KC-01C). The
airborne dust removal efficiency of a filter unit was calculated
from the results.
[0089] [Torsion]
[0090] The torsion was calculated by measuring the distance in
which a holding frame was moved owing to the strain when force was
applied to the filtration material face in one end of the holding
frame in the vertical direction while a side face in the opposed
other end of the holding frame being fixed in the filtration
material width direction, dividing the distance with the width of
the side face of the holding frame and multiplying the obtained
value by 100.
[0091] [Installation Easiness]
[0092] In the handling work at the time of installation of filter
units in a stand of a gas treatment apparatus, those which could be
installed by one time insertion were regarded to be excellent in
handling property and those which required two or more repeated
insertion works to be installed were regarded to be inferior in
handling property.
EXAMPLE 3
[0093] As a filter part, a sheet having 1.1 mm filtration material
thickness, 22 to 26 kg-cm toughness in the width direction, 45 to
50% modulus of compressive elasticity in the thickness direction,
40% or higher removal efficiency of airborne dust of 0.3 .mu.m
particle size, and 90 Pa or lower pressure loss was pleated in 39
mm height of pleats and 9 mm intervals of pleats and then cut in
105.5 filtration material width. The filtration material 5 was
inserted into the insert part, that is, the filtration material
insertion part 15, of the dies previously made ready and shown in
FIG. 4. After the filtration material 5 was inserted into the dies,
polypropylene resin (produced by C & CTECH Co.) melted at
215.degree. C. was poured to the gap between dies as shown in FIG.
4 by an injection-molding apparatus from gates at 6 points through
resin fluidizing routes 8 of the dies shown in FIG. 3 by applying
pressure of 50 kgf/cm.sup.2. At that time, the injection time to
the dies was 15 seconds and cooling after the injection was carried
out for 35 seconds. After that, the dies were separated up and down
to take out a filter unit.
[0094] Consequently, a filter unit was obtained and it had the
filter unit outer size of 106 mm.times.222 mm.times.40 mm, the
filter part size of 103 mm.times.216 mm.times.39 mm, pleat
intervals of 9 mm and comprised a filter holding frame having the
holding frame thickness of 1.5 mm, the rib thickness of 0.5 mm, and
the rib width 6 mm. The properties of the filter unit as a filter
were measured and the installation easiness at the time of
installation in a stand of a gas treatment apparatus was
judged.
EXAMPLE 4
[0095] The same filter part as that of Example 3 was used. The
formation method of the filter unit was also same as in Example 3
except that the thickness of flowing-in part of dies for a resin
was changed. Consequently, the thickness of the filter holding
frame was 1.0 mm, the rib thickness was 0.7 mm, and the rib width
was 15 mm.
EXAMPLE 5
[0096] The same procedure as Example 4 was employed except that the
number of gates was decreased to 4 points to obtain a filter unit
having the thickness of the filter holding frame of 1.5 mm, the rib
thickness of 0.5 mm, and the rib width of 10 mm. Hereinafter, the
same as Example 1.
EXAMPLE 6
[0097] The same conditions as those in Example 3 were employed to
obtain a filter unit having the thickness of the filter holding
frame of 1.9 mm, the rib thickness of 0.9 mm, and the rib width of
15 mm. Hereinafter, the same as Example
EXAMPLE 7
[0098] The same conditions as those in Example 3 were employed
except that an elastomer resin [produced by Mitsui Chemicals Inc.,
MILASTOMER (trade name)] was used as a molding resin instead of the
polypropylene resin.
EXAMPLE 8
[0099] The same conditions as those in Example 7 were employed
except that no rib was formed.
COMPARATIVE EXAMPLE 6
[0100] The same conditions as those in Example 3 were employed for
the filter part and filter unit formation method except that the
number of gates was decreased to 2 points and no rib was
formed.
COMPARATIVE EXAMPLE 7
[0101] The same conditions as those in Comparative Example 6 were
employed for manufacturing the filter unit except that the
thickness of the filter holding frame was slightly thinned.
[0102] COMPARATIVE EXAMPLE 8
[0103] The same conditions as those in Comparative Example 7 were
employed for manufacturing the filter unit except that the number
of gates was made to be 4 as same in Example 5.
[0104] Using the filter units obtained in the above-described
methods, the properties and the capabilities, mainly the
installation easiness, as a filter were evaluated and the results
are shown in Table 2.
2 TABLE 2 Evaluation Effective surface Airborne Holding area of
Resin Molding dust Rib The no. frame filter use fraction removal
Pressure thickness Rib width of thickness Torsion part amount
defective efficiency loss Installation (mm) (mm) gates (mm) (%)
(m.sup.2) (g) (%) (%) (Pa) easiness Example 3 0.5 6 6 1.5 100 0.178
47.3 0.6 52.3 155 Excellent Example 4 0.7 15 6 1.0 120 0.180 45.1
0.9 52.8 153 Excellent Example 5 0.5 10 4 1.5 60 0.178 47.7 1.25
52.2 155 Excellent Example 6 0.9 15 6 1.9 2 0.176 49.7 0.6 52.1 156
Excellent Example 7 0.5 6 6 1.5 25 0.178 47.3 1 52 155 Excellent
Example 8 -- -- 6 3 23 0.173 56.8 2 50 165 Excellent Comparative --
-- 2 3 155 0.173 56.8 1.4 50.7 165 Inferior Example 6 Comparative
-- -- 2 2.5 160 0.175 53.5 2.6 51.3 161 Inferior Example 7
Comparative -- -- 4 2.5 160 0.171 53.6 2.8 51.2 163 Inferior
Example 8
* * * * *