BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a gas/liquid separation element, a gas/liquid separator
and a gas/liquid separation unit for use in a wide range of gas/liquid separation
applications, and in particular to a humidifying element, humidifier and humidifier
unit adapted for use in a wide range of air conditioning applications requiring humidification,
and especially in humidified air conditioning applications for office buildings, factory
environments, households and vehicles.
2. Description of Related Art
[0002] To date, gas/liquid separators employing gas/liquid separation membranes to separate
gases from liquids have been employed in various fields such as humidification, dehumidification,
degassing, gas dissolving and so on (gas dissolving, i.e. dissolving a gas into a
liquid, is included in the definition of gas/liquid separation herein). In particular,
membrane type humidifiers have enjoyed a sudden surge in popularity in recent years
due to their more efficient and cleaner humidification relative to the evaporator
plate type humidifiers used to date.
[0003] Humidifiers of this type, namely, moisture permeable membrane type humidifiers employing
porous sheeting hydrophilic polymer material (herein below also termed "first type
humidifiers"), have been proposed (Unexamined Patent Applications 5-286039, 7-4701).
Humidifiers of this kind employ a tubular membrane element formed from sheet material,
which itself is a laminate of reinforcing material with a hydrophobic polymer membrane
that blocks passage of water, but allows water vapor to pass. A liquid spacer is arranged
within the tubular membrane element to ensure an internal flow channel for the humidification
water, which is coiled into a spiral configuration together with a corrugated spacer
for ensuring a gas flow channel, and accommodated within a mounting frame. In some
instances an air bleed line is provided to enhance humidification efficiency.
[0004] To operate a first type humidifier, humidifying water is supplied into the tubular
membrane element from a water inlet, and air is introduced into an opening in the
mounting frame. The water inside the tubular membrane element is released in the form
of water vapor through the hydrophilic polymer membrane, to effect humidification.
[0005] Humidifiers of the first type, however, have a number of problems, such as the following.
(1) A pinhole or liquid flow channel blockage, even at a single location in the tubular
membrane, may result in the entire humidifier becoming nonfunctional, or in reduced
humidifying performance.
(2) The tubular membrane may expand due to the pressure of the humidification water,
thereby constricting the gas flow passage, resulting in increased pressure loss in
the gas system and diminished gas flow. Expansion of the tubular membrane may also
result in increased contact area between the waterproof/moisture permeable membrane
and the corrugated spacer defining the gas flow channel, so that humidifying performance
is depressed.
(3) The corrugated spacer for defining the gas flow channel has a large number of
peaks spaced at relatively small intervals so as to ensure gas flow, as a result of
which there is a large contact area between the corrugated spacer and the waterproof/moisture
permeable membrane, and significant loss of humidifying performance.
(4) In order to achieve the desired humidifying performance, it is necessary to coil
a very long tubular membrane (as long as 10 m or more) together with a corrugated
spacer to produce the humidifier, resulting in a complex manufacturing process and
high costs.
(5) It is necessary for tubular membrane connections to the water feed line or air
bleed line to be liquid-tight; the difficulty of fabrication of these components results
in significant loss, and consequently increased cost.
[0006] A humidifier plate type has been proposed by way of another type of humidifier (herein
below also termed "second type humidifier") (Unexamined Patent Application 8-128682).
This kind of humidifier has a structure wherein a stack of a plurality of independent
humidifier plates (these consist of porous films of hydrophobic polymer) of thin foliate
configuration is accommodated within a mounting frame, with each humidifier plate
having waterproof/moisture permeable membrane stacked on the two principal faces of
a frame having an opening therein, and with the humidifier plate supplied with water
from an end thereof to a humidifier portion situated between the waterproof/moisture
permeable membranes in the frame. Accordingly, each frame is thicker in the portion
thereof defining the water feed portion that in the portion thereof defining the humidifier
portion; the humidifier plates are stacked together with the water feed portions thereof
juxtaposed, so that gaps are produced between humidifier plates due to the thickness
difference between the water feed portion and humidifier portion of the frame, to
ensure that gaps, serving as gas flow channels, are present between the humidifier
plates.
[0007] To operate a second type of humidifier of this kind, humidifying water is supplied
from a water inlet, and air is introduced into an air inlet opening in the mounting
frame. The water supplied to the humidifier plates is released in the form of water
vapor through the hydrophilic polymer membrane, to effect humidification.
[0008] However, since the design of the humidifier of the second type employs a stack of
a plurality of humidifier plates of thin foliar configuration, while problems (1)
and (4) pertaining to the humidifier of the first type described above are solved,
other problems, such as the following, remain.
(1) Where no corrugated spacer is used in the gas flow channel, the waterproof/moisture
permeable membranes can expand due to water pressure, thereby constricting the gas
flow passage, resulting in increased pressure loss in the gas system and diminished
air flow. Deformation of the waterproof/moisture permeable membranes can be reduced
to some extent by providing the frame with ribs (the back face of the waterproof/moisture
permeable membrane being stuck to the ribs), but where water pressure is high the
waterproof/moisture permeable membrane will tend to come away from the rib, possibly
resulting in rupture of the waterproof/moisture permeable membrane and water leakage.
(2) Where a corrugated spacer is used in the gas flow channel, the corrugated spacer
that defines the gas flow channel will have a large number of peaks spaced at relatively
small intervals so as to ensure gas flow, as a result of which will be a large contact
area between the corrugated spacer and the waterproof/moisture permeable membrane,
and significant loss of humidifying performance. High water pressure will result in
larger contact area between the waterproof/moisture permeable membrane and the corrugated
spacer, depressing humidifying performance.
(3) Fabricating a humidifier composed of a stack of a plurality of humidifier plates
involves first bonding or fusing waterproof/moisture permeable membranes to a frame
to produce the humidifier plate, and then stacking and bonding the desired number
of humidifier plates one at time, resulting in a production process that is complicated,
involves numerous steps, and is costly.
(4) Since the water feed portion of the humidifier plate has an open mouth structure,
individual humidifier plates cannot be inspected for pressure-induced water leaks;
rather the assembled humidifier must be inspected for pressure-induced water leaks,
so leakage in even a single humidifier plate renders the entire humidifier unusable.
[0009] As yet another type of humidifier, there has been proposed one employing a humidifier
sheet of unified triple-layer construction (herein below also termed "third type humidifier")
(Unexamined Patent Application 2000-274754). This kind of humidifier employs a humidifier
sheet of unified triple-layer construction, comprising waterproof/moisture vapor permeable
membranes that block passage of water but allow passage of water vapor, arranged on
both sides of a humidifying water retaining layer for accommodating and retaining
water for humidification. The humidifying water retaining layer consists of cloth
having a three-dimensional configuration, composed of a facing fabric, a backing fabric,
and connecting threads connecting these at predetermined intervals over the entire
extension thereof. The three-dimensional cloth is composed of hydrophilic polymer
material, subjected to hydrophilic treatment. The humidifying element is produced
by producing a through-hole at a predetermined location in the humidifier sheet, the
side wall of the through-hole constituting a water inlet, with the peripheral side
portions of the humidifying element having a sealed structure to prevent passage of
at least water. A plurality of these humidifying elements are arranged in parallel,
via spacers, within a mounting frame composed of upper and lower fixing covers and
side panels, placing them within the mounting frame either flat or folded in a pleated
configuration, or coiled into a coiled configuration with an intervening corrugated
spacer, to assure a gas flow passage.
[0010] To operate a third type of humidifier of this kind, humidifying water is supplied
from a water inlet, and air is introduced into an opening in the mounting frame. The
water supplied to the humidifier plates is released in the form of water vapor through
the hydrophilic polymer membrane, to effect humidification.
[0011] The third type of humidifier employs a humidifier sheet of unified triple-layer construction
comprising a humidifying water retaining layer and waterproof/moisture permeable membranes,
and as such the waterproof/moisture permeable membranes are more resistant to deformation
than are the waterproof/moisture permeable membranes used in humidifiers of the second
type, but nevertheless has room for improvement with regard to the following points.
(1) As the liquid flow channel is formed by cloth of three-dimensional structure,
it is susceptible to deposits on fiber surfaces of foreign matter or impurities (such
as rust, algae etc.) and tends to clog. Additionally the high cost of the three-dimensional
cloth is a significant factor contributing to higher overall cost of the humidifier.
(2) Where the unit is used at high water pressure, stress is produced at the waterproof/moisture
permeable membrane/three-dimensional cloth interfaces, making it necessary to control
water pressure so that the humidifier is not subjected to excessive pressure. This
imposes significant limits in terms of device design.
(3) The corrugated spacer that defines the gas flow channel will have a large number
of peaks spaced at relatively small intervals so as to ensure gas flow, as a result
of which will be a large contact area between the corrugated spacer and the waterproof/moisture
permeable membrane, and significant loss of humidifying performance.
(4) Since construction of the unit by stacking a plurality of humidifier sheets involves
first fabricating humidifier units by bonding a humidifier element and corrugated
spacer in proximity to the through-hole in the humidifier element, and then stacking
and bonding together the desired number of humidifier units one at a time while aligning
the through-holes, this results in a production process that is complicated, involves
numerous steps, and is costly. Further, it is necessary to ensure that the connected
portions around the through-holes are liquid-tight; the difficulty of fabrication
of these components results in significant loss, and consequently increased cost.
[0012] These and other purposes of the present invention will become evident from review
of the following specification.
SUMMARY OF THE INVENTION
[0013] The present invention provides a gas/liquid separation element that does not expand
when pressurized by liquid feed; that requires no separate components such as reinforcing
members or gas flow channel spacers; that is readily assembled with a mounting frame
so as to provide low production costs; that effectively prevents clogging and blockage;
that effectively prevents bulging of the waterproof/moisture permeable membranes;
that has excellent stability over prolonged periods; and that is particularly useful
for humidification and dehumidification applications. Also provided are a gas/liquid
separator and gas/liquid separation unit employing this element.
[0014] The present invention is a gas/liquid separation element comprising: a preferably
thin frame having an opening therein; waterproof/moisture permeable sheets affixed
to both sides thereof so as to cover the opening, whereby said frame and said waterproof/moisture
permeable sheets define a liquid flow channel; a plurality of ribs arranged over the
front face of said waterproof/moisture permeable sheets, and extending between two
opposite sides of said frame; and a liquid inlet/outlet portion for liquid feed or
liquid outlet, provided at one or more locations in a portion of said frame.
[0015] In another embodiment, the invention provides a gas/liquid separation element comprising:
a preferably thin frame having an opening; waterproof/moisture permeable sheets affixed
to both sides thereof so as to cover the opening, whereby said frame and said waterproof/moisture
permeable sheets define a liquid flow channel; a plurality of ribs arranged over the
front and back faces of said waterproof/moisture permeable sheets, with said ribs
arranged over said back faces being partially cut away; and a liquid inlet/outlet
portion for liquid feed or liquid outlet, provided at one or more locations in a portion
of said frame.
[0016] In another embodiment, the invention provides a gas/liquid separation element comprising:
two gas/liquid separation element materials, each said material comprising a frame
of having an opening; a waterproof/moisture permeable sheet affixed to the front face
thereof so as to cover the opening, a plurality of ribs arranged over the front face
of said waterproof/moisture permeable sheet, and extending between two opposite sides
of said frame, with said materials being juxtaposed back-to-back and unified by bonding
or fusing, and said frame and said waterproof/moisture permeable sheets defining a
liquid flow channel; and a liquid inlet/outlet portion for liquid feed or liquid outlet,
provided at one or more locations in a portion of said frame.
[0017] In another embodiment, the invention provides a gas/liquid separation element comprising:
two gas/liquid separation element materials, each said material comprising a frame
having an opening; a waterproof/moisture permeable sheet affixed to the front face
thereof so as to cover the opening, a plurality of ribs arranged over the front and
back faces of said waterproof/moisture permeable sheet, and extending between two
opposite sides of said frame, with said materials being juxtaposed back-to-back and
unified by bonding or fusing; said frame and said waterproof/moisture permeable sheets
defining a liquid flow channel, and said ribs arranged over said back faces being
partially cut away; and a liquid inlet/outlet portion for liquid feed or liquid outlet,
provided at one or more locations in a portion of said frame.
DESCRIPTION OF THE DRAWINGS
[0018] The operation of the present invention should become apparent from the following
description when considered in conjunction with the accompanying drawings, in which:
Figure 1 is a perspective view showing the overall configuration of an exemplary humidifier
element according to the invention.
Figure 2 (a) is a side view of the humidifier element of Figure 1; (b) is a plan view
thereof; and (c) is a front view thereof.
Figure 3 is a fragmentary plan view of the humidifier element of Figure 1, showing
the water feed port portion enlarged.
Figure 4 (a) is a sectional view taken along line A-A' in Figure 1, (b) is a sectional
view taken along line B-B', (c) is a sectional view taken along line C-C', and (d)
is a sectional view taken along line D-D'.
Figure 5 is a sectional view of an example additionally provided with ribs on the
back face of the waterproof/moisture permeable sheet.
Figure 6 is a perspective view showing the overall configuration of an exemplary humidifier
element material.
Figure 7 is a perspective view showing the obverse of the humidifier element material
of Figure 6.
Figure 8 is a partly cutaway perspective view showing the overall configuration of
an exemplary humidifier (horizontal humidifier) of the invention.
Figure 9 is a partly cutaway perspective view showing the overall configuration of
an exemplary humidifier element having water inlet/outlet portions at two locations
on two sides.
Figure 10 is a partly cutaway perspective view showing the overall configuration of
an exemplary veridical humidifier of the invention.
Figure 11 is a diagram showing an exemplary arrangement for a dehumidifying system
of the invention.
Figure 12 is a diagram showing a humidification performance measuring unit used for
evaluating performance of the humidifiers of the Examples and Comparisons.
DETAILED DESCRIPTION OF THE INVENTION
[0019] A fuller understanding of the gas/liquid separation element herein is provided by
the following detailed description made with reference to the accompanying drawings,
taking the specific example of a humidifier element for use in humidification.
[0020] Fig. 1 is a perspective view showing the overall configuration of an exemplary humidifier
element according to the invention. Fig. 2 (a) is a side view; (b) is a plan view;
and (c) is a front view. Fig. 3 is a fragmentary plan view showing the water feed
port portion enlarged. Figs. 4(a) -(d) are linear sectional views respectively taken
along lines A-A', B-B', C-C' and D-D' in Fig. 3.
[0021] As shown in the drawings, humidifier element 10 herein comprises a frame 11 produced
by removing an interior portion of a thin rectangular plate to form an opening, and
waterproof/moisture permeable sheets 12, 13 affixed to either side thereof, covering
the opening. Apart from a water inlet/outlet portion 14, the waterproof/moisture permeable
sheets 12, 13 provided to the frame 11 produce a hermetic liquid flow passage (humidifier
portion) that does not allow humidification water to pass. On the front faces of the
waterproof/moisture permeable sheets 12, 13 there are arranged a plurality of ribs
15 extending between a pair of opposing sides 11A, 11B of frame 11, i.e., in the cross
direction of frame 11. The ribs 15 have the function of defining an air flow passage
between humidifier elements 10 when humidifier elements 10 are assembled into a humidifier,
and also serve to maintain proper shape in the humidifier portion formed by the waterproof/moisture
permeable sheets 12, 13. At a first end of frame 11 there is provided a water inlet/outlet
portion 14, within which is formed a water inlet/outlet orifice 14' that communicates
with the liquid flow passage. The end of frame 11 opposite the water inlet/outlet
portion 14 is closed. In other words, the water inlet/outlet orifice in this humidifier
element is situated at a single location.
[0022] Materials for frame 11 may be selected from any number of rigid materials, such as
ABS, polyethylene, polypropylene, nylon, POM, PPS, polyvinyl chloride, acrylic, polycarbonate
and other plastics; or aluminum, stainless steel, titanium and other metal alloy materials.
The configuration of frame 11 is not critical provided that the aforementioned liquid
flow passage (humidifier portion) is formed therein; however, an approximately rectangular
configuration is preferable in terms of maximizing waterproof/moisture permeable membrane
area for a given humidifier volume. The dimensions of frame 11 may be selected appropriately
with reference to the size of the humidifier being produced; typical dimensions are
thickness of about 0.5 to about 10 mm at sides 11A and 11B; thickness of about 0.5
to about 20 mm at sides 11C and 11D; a lengthwise dimension of about 20 to about 500
mm; a crosswise dimension of about 20 to about 500 mm; side 11A, 11B width of about
2 to about 20 mm; and side 11C, 11D width of about 2 to about 30 mm. Thinner sides
11A, 11B, 11C, 11D afford greater waterproof/moisture permeable membrane area for
a given humidifier volume and higher humidification efficiency, but if thinner than
0.5 mm, pressure loss may increase excessively, and the element may lack strength,
causing the element to deform due to water pressure.
[0023] In a preferred embodiment of the humidifier element herein, the cross-sectional profile
of the edge portions of frame 11 against which air will be directed when the humidifier
is assembled, that is, the cross-sectional profile of the portion extending from the
air inlet into the voided portion and/or the profile of the portion extending from
the voided portion to the air outlet, will be of streamlined or other profile providing
minimal air flow resistance, in order to minimize pressure loss in the air system.
[0024] Any of a number of materials may be used for waterproof/moisture permeable sheets
12, 13 provided that these are waterproof and moisture permeable, i.e. do not allow
liquids (such as water) to pass, while allowing water vapor to pass; representative
examples are waterproof/moisture permeable membranes, and waterproof/moisture permeable
membrane/protective sheet laminates. Waterproof/moisture permeable sheets will preferably
have a high degree of moisture permeability, typically 5,000 - 150,000 g/m
2 · day, preferably 10,000 -100,000 g/m
2 · day, and more preferably 20,000 -70,000 g/m
2 · day. Moisture permeability herein is measured in accordance with the method of
JIS 1099-B1.
[0025] Porous polymer film is preferred for use as the waterproof/moisture permeable membrane
herein. Typical porous polymer film materials include hydrophobic, porous membranes
of polyethylene, polypropylene, polycarbonate, polytetrafluoroethylene, polytetrafluoroethylene/hexafluoropropylene
copolymer, polyvinyl fluoride, polyvinylidene fluoride, etc.; porous polytetrafluoroethylene
is preferred for its resistance to heat and chemicals. The porous polytetrafluoroethylene
material will preferably have thickness of 1-1,000 µm, porosity of 5 -95%, and pore
size of 0.01 -15 µm. In terms of achieving satisfactory levels of water vapor permeability,
water resistance and strength, thickness of 20 -200 µm, porosity of 60 -90%, and pore
size of 0.1 -3 µm are preferred. Porous polytetrafluoroethylene materials of this
kind may be produced by methods known in the art, such as stretching, solvent extraction
or casting. Stretching provides excellent membrane strength, at relatively low cost.
Methods for producing porous polytetrafluoroethylene by stretching are disclosed inter
alia in Kokai 46-7284 and 50-22881, and Tokuhyo 03-504876, and any of these known
methods may be used.
[0026] The porous polytetrafluoroethylene membrane may be provided on one or both faces
thereof with a continuous coating of hydrophilic polymer, e.g. at least partly crosslinked
polyvinyl alcohol, cellulose acetate, or cellulose nitrate, or with a polyamino acid,
polyurethane resin, fluororesin, silicone resin or other hydrophilic resin, as taught
in the publications mentioned above.
[0027] The porous polytetrafluoroethylene membrane may also be coated on the porous matrix
surfaces thereof with an organic polymer having water repellency and oil repellency,
in such as way as to leave open cells, as taught in the publications mentioned above.
For example, a fluorinated surfactant (e.g. ammonium perfluorooctanoate) may be used
to produce an aqueous emulsion of a polymer derived by polymerization of a fluoroalkyl
acrylate and a fluoroalkyl methacrylate, applying the emulsion to the porous polytetrafluoroethylene
membrane and heating it to form a film like that described above, as taught inter
alia in WO94/22928 and WO/95/34583. Organic polymers for this purpose include binary
or ternary copolymers of tetrafluoroethylene with monomers such as acrylate, methacrylate,
styrene, acrylonitrile, vinyl, allyl or alkene, preferable examples being fluoroacrylate/tetrafluoroethylene
copolymer, or fluoroacrylate/ hexafluoropropylene/tetrafluoroethylene. The above copolymers
excel in terms of resistance to soiling, heat and chemicals, and also conform and
bond securely to porous matrix surfaces. Other organic polymers include AF POLYMER
(trademark of DuPont) and CYTOP (trademark of Asahi Glass). The organic polymer may
be coated onto the porous matrix surfaces of the porous polymer film by first dissolving
the polymer in an inert solvent, such as FLUORINERT (trademark of 3M), impregnating
this into the porous polymer film, and then evaporating out the solvent.
[0028] Alternatively, waterproof/moisture permeable sheets 12, 13 may consist of laminate
material of waterproof/moisture permeable membrane with a protective sheet as a reinforcing
layer. The protective sheet may take the form of woven, knit or nonwoven fabric, netting,
expanded sheeting, porous film etc., but woven, knit and nonwoven fabrics are preferred
for their excellent reinforcement, pliability and low cost. Materials for these include
polyethylene, polypropylene, polyester, nylon, polyurethane, polyvinyl chloride and
other resin materials, metals, glass and so on. Textile fabrics such as woven, knit
and nonwoven fabrics will preferably be composed of core/sheath fibers. By using a
resin material with a lower melting point than the core component as the sheath component
(for example, a polyester core and a polyethylene sheath), the process of fusing the
waterproof/moisture permeable membrane and protective sheet when thermally laminating
these may be facilitated. Where a protective sheet is used, thickness thereof is from
5 µm to 5 mm, preferably about 10 µm to 1 mm. Thickness of less than 5 µm will not
provide adequate protection, whereas in excess of 5 mm the waterproof/moisture permeable
sheet will be thicker, and consequently the humidifier will be bulky.
[0029] Protective sheeting may be laminated to one or both sides of the waterproof/moisture
permeable membrane; in preferred practice, however, protective sheeting will be provided
on one side only, and the product used with the waterproof/moisture permeable membrane
arranged facing the air system, so as to provide good humidification efficiency. Where
the waterproof/moisture permeable membrane is situated on the air system side, diffusion
resistance on the air system side is fairly low, allowing water vapor passing through
the waterproof/moisture permeable membrane to rapidly diffuse into the air.
[0030] Methods for laminating protective sheeting to the waterproof/moisture permeable membrane
include applying adhesive to the waterproof/moisture permeable membrane with a gravure-patterned
roll, and then arranging protective sheeting thereon and compressing with a roll;
spraying adhesive onto the waterproof/moisture permeable membrane, and then arranging
protective sheeting thereon and compressing with a roll; thermally fusing the juxtaposed
waterproof/moisture permeable membrane and protective sheeting using a heated roll;
or other such methods known in the art. Where adhesives are used, urethane, polypropylene,
polyethylene, epoxy, silicone or other such adhesives may be used. The waterproof/moisture
permeable membrane and protective sheeting will have contact area of 3 to 95%, preferably
10 to 50%. Contact area of less than 3% will result in inadequate bonding strength
between the waterproof/moisture permeable membrane and protective sheeting, while
adequate humidifying ability is not achieved in excess of 95%.
[0031] As noted, ribs 15 perform the functions of defining an air flow passage between humidifier
elements, and maintaining proper shape in the humidifier portion (i.e. preventing
excessive bulging). Materials, like those for frame 11, may be selected from any number
of rigid materials, such as ABS, polyethylene, polypropylene, nylon, POM, PPS, polyvinyl
chloride, acrylic, polycarbonate and other plastics; or aluminum, stainless steel,
titanium and other metal alloy materials. The material may be the same as or different
from that used for frame 11.
[0032] Rib 15 thickness and placement are not critical provided that space for a proper
air flow passage is maintained; typically, ribs are from 0.1 to 10 mm, and arranged
substantially parallel to sides 11C and 11D, at intervals of 5 -100 mm; preferred
values are thickness of from 0.3 to 3 mm and spacing of 10 to 30 mm. For a given number
of humidifier elements and waterproof/moisture permeable sheet dimensions, physical
properties and air flow rate, thinner ribs 15 allow for faster flow speeds of air
contacting the waterproof/moisture permeable membrane, and consequently increased
humidifying action. On the other hand, thicker ribs 15 will increase air resistance.
Accordingly rib 15 thickness is a design element that must be selected with reference
to the performance required of the humidifier element.
[0033] The two ends of each rib 15 may be at least partially joined and unified with sides
11A and 11 B. Unifying the ends of the ribs at least in part with sides 11A and 11B
allows stress created by water pressure on the humidifier element, in a direction
inducing the waterproof/moisture permeable membranes 12, 13 to bulge outward, to be
borne by the frame as whole. Rib 15 placement may be substantially parallel to sides
11A and 11B, or an arrangement such that a plurality of ribs intersect at locations
over the waterproof/moisture permeable membrane; in this latter instance, it may be
necessary to cut away portions of the ribs 15 to ensure an air flow passage.
[0034] Ribs 15 may be provided as physically separate elements from waterproof/moisture
permeable membranes 12, 13, or fused and unified therewith.
[0035] In the exemplary arrangement described above, ribs 15 are provided only on the front
faces of waterproof/moisture permeable membranes 12, 13, but where additional reinforcement
of the humidifier element is the goal, ribs may be provided on the back faces of waterproof/moisture
permeable membranes 12, 13 as well. This arrangement is illustrated in Fig. 5 (Fig.
5 is analogous to a linear sectional view taken along line C-C' in Fig. 3.) Symbol
15' denotes ribs provided on the back faces of waterproof/moisture permeable membranes
12, 13; in this example, the two ribs 15' [provided to the respective membranes] are
merely juxtaposed, but could be unified instead. Where ribs 15' are provided, extension
of these over the entire cross direction will prevent passage of humidifying water,
so it will be necessary to provide cutouts 16 to allow humidifying water to pass through
the element. The number and dimensions of the cutouts will be selected appropriately
for the desired balance of reinforcement and passage of humidifying water.
[0036] Ribs 15' may be provided as physically separate elements from waterproof/moisture
permeable membranes 12, 13, or fused and unified therewith.
[0037] Methods for affixing the waterproof/moisture permeable sheets 12, 13 to the frame
11 include affixing the waterproof/moisture permeable sheets 12, 13 through integral
molding thereof when molding the frame 11 (where frame 11 is plastic); adhesively
bonding them to frame 11 with a urethane, polypropylene, polyethylene, epoxy, silicone,
solvent, acrylic or other adhesive; fusion by methods such as ultrasonic fusion, high
frequency fusion, thermal fusion etc. (where frame 11 or waterproof/moisture permeable
sheets 12, 13 are thermoplastic), or other known techniques.
[0038] Where a molding process is selected as the fixing method, the use of injection molding
is especially preferred as it allows for simultaneous integral molding of the waterproof/moisture
permeable sheets, frame and ribs. In an injection molding process, injection molding
is used to integrally mold a humidifier element material 17 in which a waterproof/moisture
permeable sheet is fixed to the surface of a frame having an opening therein produced
by injection molding, so as to cover the opening, and a plurality of ribs extend over
the surface of the waterproof/moisture permeable sheet, between a pair of opposing
sides of the frame. Two of these humidifier element materials 17 are then stacked
back-to-back and unified adhesively or by fusion to produce a humidifier element.
The humidifier element material is shown in perspective view in Figs. 6 and 7. Fig.
6 shows the humidifier element material viewed from the side thereof provided with
ribs 15, and Fig. 7 shows the obverse.
[0039] The injection molding process entails first setting the waterproof/moisture permeable
sheet on the lower mold of the injection mold assembly; closing the lower and upper
molds; injecting resin to effect injection molding; and then parting the lower and
upper molds. Setting of the waterproof/moisture permeable sheet may be accomplished
by securing with pins, by suction provided by a vacuum pump, etc. Where injection
molding is used, the material may consist of any injection-moldable resin, although
ABS resin is preferred for its excellent resistance to heat and water, and ease of
fusion. Where injection molding is conducted using ABS resin, preferred process parameters
for injection molding are an injection temperature of 190 -240°C, injection time of
5 -20 sec, cooling time of 5 -20 sec, and mold temperature or 50 -70°C.
[0040] The method for adhesively joining or fusing two humidifier elements back-to-back
to unify them may be selected from any of a number of methods affording watertight
joining/unification, such as methods using urethane, polypropylene, polyethylene,
epoxy, silicone, solvent, acrylic or other adhesives; or methods such as ultrasonic
fusion, high frequency fusion, thermal fusion etc.
[0041] As the method of attaching ribs 15, 15', where frame 11 is produced by a molding
process, ribs may be molded simultaneously with frame 11; or attached afterward. Where
attached afterward, methods such as adhesion, fusion, solvent welding, etc. may be
employed.
[0042] In the above exemplary arrangement, water inlet/outlet portion 14 extends out from
the center of the sidewall at a lengthwise end of the humidifier element; apart from
the water inlet/outlet orifice 14', the water inlet/outlet portion 14 must be unified
in watertight fashion. The position, configuration and dimensions of water inlet/outlet
orifice 14' and water inlet/outlet portion 14 may be selected as appropriate to provide
the proper supply of humidifying water into the humidifier element. Alternatively
the water inlet/outlet portion 14 may be omitted, instead providing water inlet/outlet
orifice 14' to a side 11C, 11D of the humidifier element; however, considerations
pertaining to joining with the mounting frame make it preferable to provide a water
inlet/outlet portion 14, since it is relatively easy to produce a watertight joint.
[0043] The description now turns to a humidifier according to the invention, employing the
humidifier element described herein above.
[0044] The overall arrangement of a humidifier of the invention is shown in perspective
view in Fig. 8. In the figure, 20 denotes the humidifier, comprising a stack 21 of
a plurality of humidifier elements 10 stacked vertically, and open at the front and
back to provide an air inlet and outlet. The stack 21 is enclosed about its perimeter
with a mounting frame 22; a humidifying water inlet channel (not shown) extends vertically
within one of the vertical frame piece 22A of the mounting frame 22. This humidifying
water inlet channel connects at a suitable location at its lower end with a water
inlet member 23, and at a suitable location at its upper end with a water outlet member
24. The water inlet/outlet portions 14 of the humidifier elements that make up the
humidifier 20 connect to the water inlet member 23 (which serves as a common humidifying
water inlet orifice) and to the water outlet member 24 (which serves as a common humidifying
water outlet orifice), respectively connected in watertight fashion to the vertical
frame piece 22A. It is preferable to provide the water inlet member 23 at the upper
side of the humidifier and the water outlet member 24 at the lower side, so as to
avoid air bubbles within the humidifier elements (i.e. a portion of the humidifier
element does not fill with water, so that air remains).
[0045] When the humidifier elements 10 are stacked up, the upper and lower ribs 15 are juxtaposed
with the edges 11 C, 11 D of the frames 11 so that air flow passage spaces 25 of corresponding
thickness are produced between sides 11C and ribs 15, and sides 11D.
[0046] The exemplary arrangement described above is a horizontal humidifier employing humidifier
elements that have a water inlet/outlet portion 14 at a single location on one side,
with the water inlet member 23 and water outlet member 24 of the humidifier provided
to a vertical frame piece 22A to which are connected the water inlet/outlet portions
14 of the humidifier elements 10; however, humidifier elements 10' having water inlet/outlet
portions 14 at two locations situated on two sides, depicted in Fig. 9, could be used
to produce a vertical humidifier like that shown in Fig. 10. Here, it is preferable
to provide water inlet member 23' to lower horizontal frame piece 22G and water outlet
member 24' to upper horizontal frame piece 22H. Reversing the positional relationship
of water inlet member 23' and water outlet member 24' may result in air bubbles, depending
on operating conditions.
[0047] In the illustrated example, humidifier 20 has a rectangular configuration, but depending
on the application could have some other suitable three-dimensional shape.
[0048] Humidifier 20 dimensions may be selected as appropriate for a particular application.
[0049] Materials for the mounting frame 22 of humidifier 20 may be selected from any number
of rigid materials, such as ABS, polyethylene, polypropylene, nylon, POM, PPS, polyvinyl
chloride, acrylic, polycarbonate and other plastics; or aluminum, stainless steel,
titanium and other metal alloy materials.
[0050] The humidifier elements 10 and mounting frame 22 may be assembled together, in the
case of the arrangement illustrated in Fig. 8 for example, by joining the water inlet/outlet
portions 14 and vertical frame piece 22A together in watertight fashion by means of
adhesive bonding, fusion, mechanical fastening, solvent welding or other method. These
same methods may also be used for joining to vertical frame piece 22B or horizontal
frame pieces 22C, 22D. To take the example of vertical frame piece 22A, orifices of
a size matching the water inlet/outlet portions 14 and equal in number to the number
of humidifier elements 10 to be attached are made in vertical frame piece 22A; when
joining the humidifier elements 10 with the vertical frame piece 22A, by inserting
all of the humidifier elements 10 into the corresponding orifices in vertical frame
piece 22A and joining them simultaneously using one of the above methods, a multitude
of humidifier elements 10 can be mounted onto the mounting frame all at once. Here,
the humidifier elements 10 may be simply stacked up; while gaps may be present between
humidifier elements 10, if the gaps between humidifier elements 10 are too large the
humidifier 20 will tend to be bulky. In preferred practice, humidifier elements 10
will be stacked such that no gaps are present between sides 11C, 11D and/or ribs 15
(i.e. these contact each other).
[0051] Where humidifier elements 10 and vertical frame piece 22A are joined with adhesive,
urethane, polypropylene, polyethylene, epoxy, silicone or other such adhesives may
be used.
[0052] Where fusion is used, methods such as ultrasonic fusion, high frequency fusion, thermal
fusion etc. can be employed.
[0053] For mechanical fastening, humidifier elements 10 may be joined to vertical frame
piece 22A with a O-ring or similar sealing member interposed between the water inlet/outlet
portions 14 and the orifices in the frame, and fastened thereto with bolts and nuts.
[0054] The humidifier herein may be employed as a humidifier unit, by connecting a plurality
thereof in series. One method for producing such a unit is to line up two or more
humidifiers therein, connecting together their water inlet members and water outlet
members, respectively, and situating the humidifying water inlet and humidifying water
outlet at respective single locations. With this method, fabricating a relatively
compact standard humidifier allows a number of these standard humidifiers to be connected
together depending on the required humidifying capability, thus obviating the need
to produce different humidifier models for different humidification requirements,
which is advantageous from a cost standpoint.
[0055] The description now turns to an air conditioner and humidifier system employing the
humidifier herein.
[0056] To take the example of a commercial air conditioning system equipped with a humidifying
function, the humidifier or humidifier unit is installed in the air conditioning system
and supplied with water through the water inlet, whereby water is supplied to the
humidifier elements. When dry air is forced by means of a forced air fan through the
air flow channels formed by ribs 15, the dry air flows across the surfaces of the
waterproof/moisture permeable sheets, and the humidification water inside the humidifier
elements evaporates through the waterproof/moisture permeable sheets, humidifying
the air. The pressure of the humidification water supplied to the humidifier elements
must be controlled to a level below the pressure which the humidifier elements can
withstand. Methods for controlling water pressure include installing a humidification
water supply tank above the humidifier, keeping the water level in the tank constant
within a certain given range by means of a water level sensor, float switch, etc.
so that water is supplied to the humidifier by a head differential; using a pressure
reducing valve to lower water pressure; or other such method known in the art. Where
space is limited, as with a compact air conditioner, it is preferable to use a pressure
reducing valve. The humidifier is installed in such a way that air flowing through
the air conditioner passed through the air flow passage of the humidifier. The humidifier
mounting location can be any suitable location in the air duct extending from the
air conditioner air intake to the blower outlet; however, where situated between the
heat exchanger unit and the blower outlet, air heated by the heat exchanger unit can
be passed through the humidifier to provide humidification in winter, when it is particularly
needed; a high water vapor pressure differential between the humidification water
and supplied air is preferable as it improves humidification efficiency. Forced air
is typically delivered by a forced air fan, air pump, etc.; where intake of air from
the outside is possible, as with an air conditioning system for a vehicle, no special
mechanism is needed to deliver forced air.
[0057] In the case of a humidifier system for use in air conditioning of an office building
or factory, the humidifier or humidifier unit is installed in the air conditioning
system and supplied with humidification water through the humidifier water inlet,
as with the air conditioning systems described above. The humidifier is arranged such
that the humidifier elements are facing the direction of air flow through the duct.
Air flowing through the duct is humidified as it passes through the air flow passages
formed by the ribs 15 of the humidifier elements.
[0058] In the case of a humidifier system for household use, the humidifier, blower, humidification
water pressure reducing valve, operation control unit, etc. will be located inside
a casing, and when supplied with water through the humidifier water inlet, the water
is supplied into the humidifier elements; when dry air forced by means of the blower
flows across the surfaces of the waterproof/moisture permeable sheets, and the humidification
water inside the humidifier elements evaporates through the waterproof/moisture permeable
sheets, humidifying the air.
[0059] While the invention has been shown and described herein above on the basis of certain
preferred embodiments, these should not be construed as limiting, a wide variety of
modifications and improvements being possible.
[0060] For example, an ultra-thin humidifier could be designed, by fabricating a humidifier
element material comprising a thin panel frame configuration having an opening and
having a waterproof/moisture permeable sheet affixed to the front side thereof so
as to cover the opening, and a plurality of ribs arranged over the front face of the
waterproof/moisture permeable sheet, extending between two opposite sides of the frame;
affixing by adhesive or by fusion the humidifier element material to the wall of an
air duct or flow passage for air to be humidified; and supplying humidifying water
to the humidifier space defined by the wall and the humidifier element material.
[0061] The humidifier element, humidifier and humidifier unit herein can also be used as
a dehumidifier element, dehumidifier and dehumidifier unit, respectively.
[0062] For use as a dehumidifier element, dehumidifier or dehumidifier unit, the humidifier
element, humidifier or humidifier unit herein may be supplied with a moisture absorbing/desorbing
solution, as the liquid supplied to the humidifier elements. Moisture absorbing/desorbing
solution refers to a solution that at low temperature absorbs moisture (water vapor)
present in air, and that at higher temperature releases moisture as water vapor; materials
known in the art may be used. Such materials include solutions containing as the solute
water-soluble organic compounds such as diethylene glycol, triethylene glycol, glycerol
etc.; or solutions containing water-soluble inorganic compounds such as lithium chloride,
potassium chloride, sodium chloride, lithium bromide, phosphoric acid, sodium hydroxide,
potassium hydroxide etc. The use of lithium chloride aqueous solution is especially
preferred. The temperature at which the moisture absorbing/desorbing solution absorbs
moisture is typically 10 to 35°C, preferably 20 to 30°C. The temperature at which
the moisture absorbing/desorbing solution releases moisture as water vapor is higher
than the temperature at which it absorbs moisture, typically 25 to 60°C, preferably
30 to 45°C.
[0063] An exemplary arrangement for a dehumidifier system is illustrated in Fig. 11. A dehumidifier
unit 26 is installed, together with a forced air fan 27, in a room to be humidity-conditioned.
The moisture absorbing/desorbing solution is passed through a heat exchanger 28 where
it is cooled to bring it to set temperature, and then enters the dehumidifier unit
26, where it removes humidity from indoor air delivered by the forced air fan 27.
The moisture absorbing/desorbing solution exiting the dehumidifier unit 26 enters
a return line, and in a diluted state (due to having absorbed moisture) enters a heat
exchanger 29 where it is heated to bring it to set temperature, and then enters the
outdoor dehumidifier unit 26. In dehumidifier unit 26 the moisture absorbing/desorbing
solution is condensed by being induced to release moisture through humidification
of outdoor air delivered by forced air fan 27. The condensed moisture absorbing/desorbing
solution is returned to heat exchanger 28 by a liquid feed pump 32, cooled, and recirculated.
Alternatively, moisture abscrbing/desorbing solution supplied to dehumidifier unit
26 may be circulated by means of a circulation regulator valve 33, to regulate the
concentration and temperature of the moisture absorbing/desorbing solution. Where
a dehumidifier unit 26 installed indoors is used for humidification, the moisture
absorbing/desorbing solution is passed through heat exchanger 28 where it is heated
to bring it to set temperature, and then enters the dehumidifier unit 26, where it
humidifies indoor air delivered by the forced air fan 27. The moisture absorbing/desorbing
solution exiting the dehumidifier unit 26 enters a return line, and in a concentrate
state (due to release of moisture) enters heat exchanger 29 where it is cooled to
bring it to set temperature, and then enters the outdoor dehumidifier unit 26. In
dehumidifier unit 26 the moisture absorbing/desorbing solution is diluted by being
induced to dehumidify outdoor air delivered by forced air fan 27. The diluted moisture
absorbing/desorbing solution is returned to heat exchanger 28 by a liquid feed pump,
heated, and recirculated. Alternatively, moisture absorbing/desorbing solution supplied
to dehumidifier unit 26 may be circulated by means of a circulation regulator valve
33, to regulate the concentration and temperature of the moisture absorbing/desorbing
solution.
[0064] Next is described an example of use of the gas/liquid separation element, gas/liquid
separator and gas/liquid separation unit herein for degassing, i.e. separating gas
from a process liquid.
[0065] Where the gas/liquid separation element, gas/liquid separator or gas/liquid separation
unit herein is used for degassing, either the gas/liquid separator is installed in
a hermetic housing, process liquid is flowed into the gas/liquid separation element,
and the air flow channel (space formed between the gas/liquid separation element and
the housing) of the gas/liquid separator is evacuated with a vacuum pump; or, in a
manner exactly analogous to the humidifier system herein described earlier, process
liquid (instead of humidification water) is flowed into the humidifier element and,
instead of air, gas having a gas partial pressure of gas to be degassed lower than
the process liquid is flowed into the air flow channel of the humidifier, to efficiently
degas the process liquid. The degassing system can be used in a manner exactly analogous
to the water supply system and humidifier system herein described earlier, but where
a vacuum pump is used for degassing, a housing providing hermetic closure to the humidifier
and a vacuum pump that can be connected to the housing to evacuate the housing will
be needed.
[0066] Next is described an example of use of the gas/liquid separation element, gas/liquid
separator and gas/liquid separation unit herein for gas dissolving, i.e. dissolving
gas into a process liquid.
[0067] Where the gas/liquid separation element, gas/liquid separator or gas/liquid separation
unit herein is used for gas dissolving, either the gas/liquid separator is installed
in a hermetic housing, process liquid is flowed into to the gas/liquid separation
element, and a gas for dissolving into the process liquid is flowed into the air flow
channel (space formed between the gas/liquid separation element and the housing) of
the gas/liquid separator; or, in a manner exactly analogous to the humidifier system
herein described earlier, process liquid (instead of humidification water) is flowed
into the humidifier element and, instead of air, gas to be dissolved is flowed into
the air flow channel of the humidifier, to efficiently dissolve the gas into the process
liquid. Where the gas being dissolved is corrosive or toxic, it is desirable to use
the former method employing a hermetic housing, so that gas does not leak into the
environment. The degassing system can be used in a manner exactly analogous to the
water supply system and humidifier system herein described earlier, but where gas
dissolving is carried out in a hermetic housing, a housing providing hermetic closure
to the humidifier and a blower etc. that can be connected to the housing to supply
gas into the housing will be needed.
[0068] By virtue of the arrangements described herein above, the invention provides the
following extremely notable benefits.
(1) As the gas/liquid separation element houses no components for forming the liquid
flow channel, e.g. spacers or fabric of three-dimensional construction, it resists
clogging by foreign matter or impurities present in liquids, and has negligible liquid
pressure loss.
(2) The ribs of the gas/liquid separation element are unified with the frame and waterproof/moisture
permeable sheeting, preventing deformation of the waterproof/moisture permeable sheeting
even when liquid pressure is high. Provision of ribs also increases the strength of
the frame per se, allowing the frame to be thinner and the gas/liquid separator to
be more compact. Where ribs are provided on the back face of the waterproof/moisture
permeable sheeting (i.e. to the inside of the gas/liquid separation element), the
strength of the frame can be increased to an even greater degree, allowing the frame
to be even thinner and the gas/liquid separator to be even more compact.
(3) Since the gas flow channel is defined by ribs, contact area with the waterproof/moisture
permeable sheeting is smaller than with conventional corrugated spacers, reducing
loss of gas/liquid separation performance.
(4) The gas/liquid separator herein can be manufactured by stacking a plurality of
gas/liquid separation elements and simultaneously adhering or fusing liquid inlet/outlet
portions formed in their frames to a mounting frame, providing a simple, inexpensive
manufacturing process.
(5) Where the waterproof/moisture permeable sheeting and frame in the gas/liquid separation
element are fixed by means of injection molding, the process can be carried out in
stable fashion, and connection with a liquid supply line or liquid outlet line can
be effected by adhering or fusing the liquid inlet/outlet portion formed in the frame
to mounting frame having a liquid inlet member or liquid outlet member, thus avoiding
the difficult process of adhesion to the waterproof/moisture permeable sheeting, eliminating
losses associated with adhesion.
(6) The gas/liquid separation element herein has a liquid inlet/outlet portion formed
in a portion of its frame, so that when the gas/liquid separation element is tested
for pressurized leakage, the liquid inlet/outlet portion can be connected to the pressurized
liquid line of the leak tester, allowing gas/liquid elements to be tested individually.
Examples
[0069] Examples of the invention and comparisons are described below.
Example 1
[0070] Porous polytetrafluoroethylene film (approximately 30 µm thick, mean pore size approximately
0.2 µm, porosity 85%) was laminated on one face thereof with polyester nonwoven fabric
(MARIKKUSU 903030WSO ex Unitika) using a heated roll, to produce waterproof/moisture
permeable sheeting. The resultant waterproof/moisture permeable sheeting had moisture
permeability of 20,000 g/m
2 · day. Next, insert molding was carried out by cutting the waterproof/moisture permeable
sheeting to 395 x 55 mm, setting it on the lower mold of the injecting mold assembly,
with the nonwoven fabric face facing upward, and performing injection molding with
resin to produce a 410 x 60 x 2.5 mm humidifier element material like that depicted
in Fig. 6 and 7. During the injection molding process the waterproof/moisture permeable
sheet was secured in place with pins provided to the mold. Rib dimensions were 1.5
mm width, 1.0 mm height; 18 of these were arranged at 20 mm pitch. The molding unit
was a Nisei Jushi Kogyo TH00-12VSE; conditions for injection molding were 30% injection
speed, 75% injection pressure, 60°C mold temperature, and 220°C resin temperature.
The resin was SAIKORAKKU X7-11001(N) from Ube Kosan.
[0071] Two of the resultant humidifier element materials were arranged back-to-back and
bonded to produce a humidifier element like that depicted in Figs. 1 to 5. The adhesive
was KP1000 ex Konishi. 24 of the these humidifier elements were stacked to produce
a 430 x 150 x 60 mm humidifier like that depicted in Fig. 8. The same Konishi adhesive
was used to bond the humidifier elements to the mounting frame. The effective membrane
surface area of the humidifier was 0.582 m
2; humidifier volume was 0.00324 m
2.
Example 2
[0072] Using waterproof/moisture permeable sheeting similar to that in Example 1, a humidifier
was fabricated in the same manner as in Example 1, except for setting it on the lower
mold of the injecting mold assembly, with the nonwoven fabric face facing downward.
Effective membrane surface area was 0.582 m
2; humidifier volume was 0.00324 m
2.
Example 3
[0073] Using the same fabrication procedure as in Example 1, a humidifier was fabricated
in the same manner as in Example 1, except for making the ribs 0.8 mm high. Effective
membrane surface area was 0.582 m
2; humidifier volume was 0.00324 m
2, the same as in Example 1.
Comparison 1
[0074] Porous polytetrafluoroethylene film (approximately 30 µm thick, mean pore size approximately
0.2 µm, porosity 85%) was coated on one face thereof with polyurethane adhesive using
a gravure roll (opening rate set to 80%), and onto this face was juxtaposed three-dimensional
fabric (0.3 mm-diameter polyester monofilament knit, 1.5 mm thick) as a humidification
water support layer, which was then roll compressed at 0.5 kg/cm
2 pressure, speed of 30 m/min. Three-dimensional fabric was then applied to the other
face by the same method and under the same conditions, to produce a triple-layer film
of compacted porous polymer film. The triple-layer film was cut to dimensions of 250
x 85 mm to produce a rectangular sheet. The perimeter of the rectangular sheet was
thermally fused with a mold, and a hole 10 mm in diameter was produced at a location
18 m from one short side of the sheet, at a point in the lateral center, to produce
a water inlet to the film interior. Fifty-eight such samples were stacked and bonded
to produce a humidifier. Effective membrane surface area of the humidifier was 1.74
m
2; humidifier volume was 0.00524 m
2.
Comparison 2
[0075] Using waterproof/moisture permeable sheeting similar to that in Example 1, a tubular
membrane element 165 mm wide and 9.3 m in length, having the nonwoven fabric face
of the waterproof/moisture permeable sheet facing outward, was fabricated. Bonding
of the joined portion of the tubular membrane element was done with polyurethane adhesive.
The resultant tubular membrane element and a vinyl chloride corrugated spacer 185
mm wide and 10 m in length were coiled in a coiled configuration and assembled in
a mounting frame, providing an inlet for humidification water to one end of the tubular
membrane element, to produce a humidifier. Effective membrane surface area of the
humidifier was 3.069 m
2; humidifier volume was 0.0137 m
2.
Results of comparison of Examples and Comparisons
(1) Liquid pressure loss comparison
[0076] Tap water was brought down to pressure of 65 kPa, injecting water into the water
inlet of the samples of Example 1 and Comparison 1 while monitoring flow rate with
a flow meter. When full, the water supply was shut off. Water was then drained from
the water inlet, measuring the time needed for 50% of the water to drain out. The
sample of Example 1 had shorter drain time, indicating lower liquid pressure loss.
[0078] Comparison 1: 112 sec
(2) Comparison of liquid pressure loss with extended operation
[0079] The samples of Example 1 and Comparison 1 were supplied with air from a duct under
conditions of a humidified flow rate of 250 m
3/h, 60°C, 40% RH environment, while supplying humidification water reduced from tap
water pressure to 65 kPa with a pressure reduction valve. No water was drained from
the humidifier during humidifier operation. After 200 hours of operation, operation
was halted, the humidifier was detached from the duct, and the water was expelled
from the humidifier.
[0080] Samples operated for 200 hours were then measured as described in (1). The Comparison
sample showed clogging of the liquid flow channel. The sample of Example 1 was virtually
unchanged from initial values, even after 200 hours of operation, and no clogging
of the liquid flow channel was noted.
[0082] Comparison 1: 156 sec
(3) Humidification performance (volume/surface area ratio)
[0083] The humidifiers of Examples 1, 2 and 3 were set in the humidification performance
measuring unit depicted in Fig. 12, and supplied with air from a duct under conditions
of a humidified flow rate of 250 m
3/h, 20°C, 40% RH environment, while supplying to the humidifier humidification water
reduced from tap water pressure to 65 kPa with a pressure reduction valve. No water
was drained from the humidifier during humidification measurement. Humidification
was converted to a 1 m
3 humidifier volume basis and a 1 m
2 humidifier surface area basis for comparison. The humidifiers of Examples 1, 2 and
3 all showed higher humidification efficiency than the Comparison humidifiers.
[0084] The humidifier of Example 1 had the nonwoven fabric situated on the air system side,
and the humidifier of Example 2 had the waterproof/moisture permeable membrane situated
on the air system side. The humidifier of Example 2 showed higher humidification performance
than the humidifier of Example 1. That is, it was found that humidification efficiency
is higher when the waterproof/moisture permeable membrane is situated on the air system
side.
[0085] The humidifier of Example 3 also showed higher humidification performance than the
humidifier of Example 1. That is, it was found that humidification efficiency is higher
when rib height is lower.
Example 1: 0.42 kg/hr, 130 kg/hr · m3, 0.72 kg/hr · m2
Example 2: 0.53 kg/hr, 164 kg/hr · m3, 0.91 kg/hr · m2
Example 3: 0.44 kg/hr, 139 kg/hr · m3, 0.77 kg/hr · m2
Comparison 1: 0.61 kg/hr, 116 kg/hr · m3, 0.35 kg/hr · m2
Comparison 2: 1.01 kg/hr, 74 kg/hr · m3, 0.33 kg/hr · m2
(4) Evaluation of Water Pressure which Humidifier Element Can Withstand (Water Pressure
Resistance)
[0086] An air pressure reduction valve was attached to a water tank, and compressed air
was supplied to pressurize the water tank, supplying the pressurized water to the
humidifier elements of Example 1 and Comparison 1. Pressure ramp-up was 2 kPa/sec.
For the humidifier element of Example 1, water pressure resistance was designated
as the level of water pressure at which water began to exude from the surface of the
waterproof/moisture permeable sheeting. For the humidifier element of Comparison 1,
water pressure resistance was designated as the level of water pressure at which the
polytetrafluoroethylene film and three-dimensional fabric delaminated. The humidifier
element of Example 1 demonstrated higher water pressure resistance than the humidifier
element of Comparison 1.
[0087] The above comparisons demonstrate the superiority of the humidifiers of Examples
1, 2 and 3.
[0088] While particular embodiments of the present invention have been illustrated and described
herein, the present invention should not be limited to such illustrations and descriptions.
It should be apparent that changes and modifications may be incorporated and embodied
as part of the present invention within the scope of the following claims.