Tubular membrane module for separation

A tubular membrane module for separation providing a plurality of perforated support tubes having a semipermeable membrane for separation provided on inner surfaces thereof, a cylindrical case having a permeated solution port provided on a drum portion thereof, a pair of first and second plastic headers attached to both ends perforated support tubes for making the perforated support tubes be communicated and header connecting means, the first header being divided into a first header outer portion having a feed solution inlet port and a concentrated solution outlet port provided on an outer surface thereof and a plurality of first communication ports which are groove-shaped provided on an inner surface thereof, and a first header inner portion held between the first header outer portion and the case and having first openings for fitting the perforated support tubes which correspond to the first communication ports, and the second header being divided into a second header outer portion having a plurality of second communication ports which are groove-shaped provided on an inner surface thereof and a second header inner portion held between the second header outer portion and the case and having second openings for fitting the perforated support tubes which correspond to the second communication ports.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a tubular membrane module (hereinafter 
sometimes referred to as a module) for separation having an 
ultrafiltration membrane and a low pressure reverse osmosis membrane, and 
more particularly to a membrane module head which is formed of plastics so 
as to be light and has high productivity. 
2. Desciption of the Prior Art 
Typically, a tubular module is disclosed in U.S. Pat. No. 4,704,205 
assigned to Daicel Chemical Industries, Ltd. In general, a module is 
widely used for concentration , separation or purification of a liquid. 
Since a membrane is provided on an inner surface of a support tube, the 
tubular membrane can be pressure-resistant, In addition, the module is 
tube-shaped so that a structure thereof can be simplified. 
However, since a pressure is applied on a head in a direction of a central 
axis of the tubular membrane, a head is made thicker in consideration of 
pressure-resistance. Consequently, a variety of problems are caused. 
Therefore, it is desired that the head has the simplified structure. 
Conventionally, the entire head is made of metal or a metallic U bend is 
embedded in a plastic head. In the former case, since a U passage is 
provided in the head, the head is increased in cost and made too heavy. 
Consequently, it is difficult to provide or convey the module. In the 
latter case, although the head is made slightly lighter as compared with 
the former case, it is difficult to center a lot of U bends. 
SUMMARY OF THE INVENTION 
To provide a plastic head which is light and has high productivity, 
pressure-resistance of the head and the simple flow of a solution in a 
module are the most important subjects. The present inventors have 
examined the above-mentioned subjects earnestly. 
The present invention provides a tubular membrane module for separation 
comprising a plurality of perforated support tubes having a semipermeable 
membrane for separation provided on inner surfaces thereof, a cylindrical 
case having a permeated solution port provided on a drum portion thereof, 
a pair of first and second plastic headers attached to both ends of the 
case and the perforated support tubes for making the perforated support 
tubes be communicated with one another horizontally, in parallel and 
zigzags so as to form a serial support tube group in the case, injecting a 
feed solution from one end of the perforated support tube to finally 
discharge a concentrated solution and a permeated solution from the end of 
the perforated support tube and the permeated solution port of the case 
respectively, and header connecting means, the first header being divided 
into a first header outer portion having a feed solution inlet port and 
concentrated solution outlet port provided on an outer surface thereof and 
a plurality of first communication ports which are groove-shaped provided 
on an inner surface thereof, and a first header inner portion held between 
the first header outer portion and the case and having first openings for 
fitting the perforated support tubes which correpond to the first 
communication ports, the second header being divided into a second header 
outer portion having a plurality of second communication ports which are 
groove-shaped provided on an inner surface thereof and a second header 
inner portion held between the second header outer portion and the case 
and having second openings for fitting the perforated support tubes which 
correspond to the second communication ports, and the header conecting 
means including a tie rod which penetrates the first header and an 
approximately central portion of a gap defined in the serial support tube 
group, a rod-shaped header fixture which penetrates a second communication 
port of the second header and has an interior screw, with which the tie 
rod is jointed in order to connect the first and second headers in tension 
provided on a tip portion thereof and a lateral hole which penetrates the 
drum portion to prevent the second communication ports from being divided, 
and auxiliary connecting means for respectively integrating the first 
header outer and inner portions and the second header outer and inner 
portions on the outer periphery. 
According to the present invention, the tubular membrane module for 
separation comprises a pair of plastic headers which are to be attached to 
both ends of a case and perforated support tubes respectively and are 
formed each as one body of two divided members. The pair of headers are 
connected by a tie rod, a header fixture and auxiliary connecting means. 
The tie rod penetrates a gap between a support tube group through a first 
header. The header fixture is inserted through a second header and is 
connected to the tie rod in order to connect the headers in tension, so 
that pressure-resistance of the headers can be improved. The auxiliary 
connecting means connect the divided members of the headers on the outer 
periphery. In addition, there is provided a lateral hole which penetrates 
a drum portion of the header fixture. Consequently, solution residence 
portions can be prevented from being generated in the perforated support 
tubes. 
According to the present invention, in the case where the both headers are 
to be formed of a plastic, it is preferred that the divided members are 
respectively formed of a plastic reinforced with an inorganic material 
such as glass fiber or carbon fiber in consideration of the strength and 
moldability of a material. 
More specifically, although the headers molded of a glass fiber reinforced 
plastic are thicker, groove-shaped communication ports and openings for 
fitting the perforated support tubes, which are formed on the headers, 
have the increased precision in dimension thereof as compared with the 
case where the headers are molded of only the plastic. 
According to the present invention, examples of a plastic material which 
are used in glass fiber reinforced plastic headers are polysulfone resins, 
polyamide resins, modified PPO (polyphenylene oxide) resins, polycarbonate 
resins, polyether imide resins, polyphenylene sulfide resins and the like. 
In particular, the modified PPO resins which are not so expensive and 
excellent in moldability can be widely used. Preferably, the content of 
the glass fiber is 5 to 40 (w/w)%, and more preferably, 30 (w/w)%. 
In FIG. 1, a first header 1 of the present invention has an O ring 7 and a 
collar 8 attached to a tie rod 6. The tie rod 6 is inserted into an 
approximately central portion 5 of a gap defined in a support tube group 4 
through a first insertion hole 2 of a first header outer portion 1a and a 
second insertion hole 3 of a first header inner portion 1b. At the time of 
assembling, the first header 1 is tightened by the collar 8 and a nut 9 of 
the tie rod 6. 
In FIG. 2 a second header 10 of the present invention includes a header 
fixture 11 which has a lateral hole 12 provided through a drum portion 11a 
and an interior screw 11b provided on a tip portion thereof. The header 
fixture 11 can be connected to the tie rod 6 with the interior screw 11b. 
In addition, the header fixture 11 has a tip portion 11c thereof engaged 
with an engagement portion 13a so as to be connected to the tie rod 6 
through a central portion 13b of a plurality of second communication ports 
13 and a third insertion hole 14 of a second header inner portion 10b. The 
second header outer portion 10a has the second communication ports 13 
formed on an inner surface thereof. The engagement portion 13b is formed 
in the middle of the third insertion hole 14. The header outer and inner 
portions 10a and 10b are tightened by a washer 6a provided on a shaft 
portion 3b of the tie rod 6, and a nut 15 fixed to a screw portion 11d of 
the fixture 11. 
The divided members of the header are ultrasonic-welded together or adhered 
to each other by means of gaskets 40 and 41 shown in FIGS. 3(e) and 4(e). 
Consequently, the headers are tightened by the tie rod and the like so 
that they can surely be prevented from being deformed when pressurized. 
According to the present invention, a solution flows in the module without 
fluctuations as shown in FIG. 5(b). Consequently, residence is not caused 
in the module. 
More specifically, the first and second header outer portions 1a and 10a 
have a plurality of first and second communcation ports 24 and 13 provided 
thereon respectively in such a manner that a serial support tube group 4 
is communicated in zigzags. In addition, the fixture 11 which is inserted 
into the second header outer portion 10a has the lateral hole 12 provided 
thereon as shown in FIG. 2. Consequently, if the module is tightened by a 
single longer bolt, the solution can be prevented from staying in the 
module as shown in FIG. 7. In other words, a residence portion 17 can be 
prevented from being generated in a perforated support tube 34a as shown 
by oblique lines. 
With a structure in which a tip portion 18a of a longer bolt 18 is 
connected to a cap nut 20 so as to tighten an inner header portion 19 as 
shown in FIGS. 6(a) and (b) a pressure is received by only the inner 
header portion 19 even if the solution may flow in a similar manner to 
FIG. 5(b). Consequently, pressure-resistance is lowered. According to the 
present invention, connecting means is provided in such a manner that both 
the second header outer and inner portions 10a and 10b receive a pressure 
applied on the second header 10. Consequently, the pressure-resistance is 
improved.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
There will be described an embodiment of the present invention with 
reference to the drawings. The present invention is not limited to the 
embodiment to be described below. 
In FIGS. 1 to 7, a tubular membrane module (hereinafter referred to as a 
module) for ultrafiltration mainly comprises 18 perforated support tubes 
4a, a cylindrical case 20, a pair of first and second headers 1 and 10 
formed of a plastic resin containing glass fiber, and header connecting 
means. The perforated support tube 4a has a ultrafiltration membrane 
provided on an inner surface thereof. The cylindrical case 20 has a 
permeated solution port 21 provided on a drum portion 20a thereof. The 
first and second headers 1 and 10 are respectively attached to both ends 
of the case 20 and the perforated support tubes 4a so that the perforated 
support tubes 4a are horizontally communicated with one another in 
parallel and in zigzags in order to form a serial support tube group 4 in 
the case 20. In addition, a feed solution is injected from one end of the 
perforated support tube 4a so that a concentrated solution and a permeated 
solution are finally discharged from the end of the perforated support 
tube 4a and the permeated solution port 21 of the case 20, respectively. 
Furthermore, the first header 1 is divided into a first header outer 
portion 1a and first header inner portion 1b which are joined at junctions 
50a and 50b. The first header outer portion 1a has a feed solution inlet 
port 22 and a concentrated solution outlet port 23 provided on an outer 
surface thereof and 8 first communication ports 24 which are groove-shaped 
(see FIG. 3 (d) provided on an inner surface thereof. The first header 
inner portion 1b is held between the first header outer portion 1a and the 
case 20 and has 18 first openings 25 for fitting the perforated support 
tubes (see FIG. 3 (c)) which correspond to the first communication ports 
24. 
The second header 10 is divided into a second header outer portion 10a and 
a second header inner portion 10b which are joined at junctions 51a and 
51b. The second header outer portion 10a has 9 second communication ports 
13 which are groove-shaped (see FIG. 4 (d)) provided on an inner surface 
thereof. The second header inner portion 10b is held between the second 
header outer portion 10a and the case 20 and has 18 second openings 26 for 
fitting the perforated support tubes which correspond to the second 
communication ports 13. 
The header connecting means includes a tie rod 6, a rod-shaped header 
(fixture 11, screw holes 27a, 27b, 28a and 28b, and connecting screws 29 
and 30 (see FIGS. 3(a), (c) and (d), and FIGS. 4 (a), (c) and (d)). The 
tie rod 6 penetrates the first header 1 at an approximately central 
portion 5 of a gap defined in the serial support tube group 4. The header 
fixture 11 has an interior screw 11b provided on a tip portion thereof and 
a lateral hole 12. In addition, the header fixture 11 penetrates the 
second communication ports 13a (see FIGS. 2 and 4 (d)) and is connected to 
the tie rod 6 with the interior screw 11b in order to connect the first 
and second headers 1 and 10 in tension. The lateral hole 12 penetrates a 
drum portion 11a to prevent the second communication ports 13a from being 
divided. The screw holes 27a, 27b, 28a and 28b and the connecting screws 
29 and 30 serve as auxiliary connecting means to unite the first header 
outer and inner portions 1a and 1b, and the second header outer and inner 
portions 10a and 10b on the outer periphery, respectively. 
EMBODIMENT 1 
A header is molded of Noryl resin (GFN3J; manufactured by EPL). Header 
portions are ultrasonically welded together or adhered to each other by 
means of gaskets 40 and 41. The header is modularized and pressurized at 
an amount of supplied water, i.e., 1.8m.sup.3 /Hr. Shown in Table 1 is a 
pressure (of a module inlet) applied when a leakage is caused at junctions 
of the header portions. 
TABLE 1 
______________________________________ 
Pressure-resistant strength of a header (kg/cm.sup.2) 
Temper- 
ature Junction First header 
Second header 
______________________________________ 
25.degree. C. 
Gasket 90 or more 80 
Ultrasonic 90 or more 80 
wave 
Adhesive (1) 
38 or more 30 
Adhesive (2) 
37 or more 31 
80.degree. C. 
Gasket 90 or more 80 
Ultrasonic 90 or more 78 
wave 
Adhesive (1) 
15 or more 10 
Adhesive (2) 
17 or more 9 
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Where an adhesive (1) is an epoxy adhesive (Araldyte AV 138; manufactured 
by Chiba Guigy) 
and an adhesive (2) is an epoxy adhesive (Cemedine 1565; manufactured by 
Cemedine Kogyo Kabushiki Kaisha) 
COMATIVE EXAMPLE 1 
Similar to embodiment 1, the case where an epoxy adhesive is used for an 
adhesive is shown in Table 1. In Table 1, a leakage is caused at the 
junctions. 
COMATIVE EXAMPLE 2 
A cap nut 20 shown in FIGS. 6 (a) and (b) is used for a header fixture. A 
header is formed of a resin to be described below in order to perform a 
pressure-resistant test. Gaskets are used for junctions. The result of the 
test is shown in Table 2. 
Where a resin (1) is Noryl: GFN3J (manufactured by EPL) 
and a resin (2) is Polysulfone (which contains glass fiber at 30 (w/w)%) 
(manufactured by Nissan Kagaku Kogyo). 
TABLE 2 
______________________________________ 
Pressure-resistant strength of a header (kg/cm.sup.2) 
Junction Second header 
______________________________________ 
Noryl 39 
Polysulfone 37 
______________________________________ 
In Table 2, a leakage is caused by damage to an inner header portion 19 of 
the second header. 
According to the present invention, a tubular membrane module for 
separation comprises a pair of plastic headers which are to be attached to 
both ends of a case and perforated support tubes respectively. Each header 
is to be integrated by two divided members. The pair of headers are 
connected by a tie rod, a header fixture and auxiliary connecting means. 
The tie rod penetrates a support tube group through a first header. The 
header fixture is inserted through a second header and connected to the 
tie rod in order to connect the headers in tension. The auxiliary 
connecting means unite the divided members of the headers on the outer 
periphery. In addition, there is provided a lateral hole which penetrates 
a drum portion of the header fixture. Consequently, solution residence 
portions can be prevented from being generated in the perforated support 
tubes. Furthermore, pressure-resistance of the headers can be improved.