Electric heating – Metal heating – Wire – rod – or bar bonding
Reexamination Certificate
2000-02-24
2003-03-25
Elve, M. Alexandra (Department: 1725)
Electric heating
Metal heating
Wire, rod, or bar bonding
Reexamination Certificate
active
06538225
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a column packing filled in a device which is divided in a plurality of chambers or channels connected to one another and performs material transfer, heat exchange or mixing between gases, liquids or gas and liquid. The invention relates also to a method for manufacturing such column packing.
Japanese Patent Application Laid-open Publication No. Hei 3-203976 discloses a column packing of this type. This column packing a made up of a plurality of permeable sheets which are disposed in parallel to one another and extend in the direction of a main stream of fluid. Projecting portions of these permeable sheets are disposed in the direction that crosses the main stream of fluid and these projections functions as spacers between the adjacent permeable sheets. This packing (hereinafter referred to as “X-packing” because the cross section of a joint portion between two adjacent permeable sheets assumes the shape of the letter X) is beneficial in that fluid flowing down along the permeable sheets is repeatedly joined, mixed, horizontally dispersed and redistributed at each joint of the permeable sheets. Thus fluid flow which was not uniform when it was charged in the device gradually becomes uniform resulting in an optimum material transfer or heat exchange. Moreover, gas charged in the device passes through the liquid flowing along the inclined surfaces of the permeable sheets and necessary contact between the gas and the liquid is achieved by contacting the gas with the liquid while the gas passes through the permeable sheets, so that material transfer or heat exchange can be effected efficiently with a minimum pressure loss.
For manufacturing this X-packing, the inventor of this application proposed the method described in U.S. Pat. No. 5,673,726. According to this method, as shown in
FIG. 22
, permeable sheets
51
in plural layers and joints
51
b
of adjacent permeable sheets
51
are simultaneously produced and a three-dimensional woven packing
50
thereby is produced.
In a case where this X-packing manufactured by the above described prior art method is used as a packing loaded in, e.g., a gas-liquid mixing device, the packing
50
of
FIG. 22
is erected in the device and liquid from a distributor is caused to flow from the top to the bottom, i.e., in the direction of arrow A. It is, however, actually difficult to maintain the packing
50
strictly horizontally in the device by reason of an error in installation or other causes and, as a result, the threads that run crosswise of the separated portions
51
a
and the joints
51
b
of the packing
50
are disposed in a somewhat inclined relationship to the horizontal direction. For this reason, when the operation of the device is started and liquid is caused to flow in the direction of the arrow A, the liquid flows concentrically along a lower portion of the threads that run crosswise with the result that collection, horizontal distribution and downward redistribution of the liquid are not performed uniformly but flow of the liquid tends to concentrate on the lower portion of the inclined threads running crosswise.
It is, therefore, an object of the invention to provide an X-packing capable of accurately achieving uniform collection and redistribution of liquid at joints of the X-packing.
It is another object of the invention to provide a method for manufacturing such X-packing at a low cost and in a large scale.
SUMMARY OF THE INVENTION
For achieving these objects of the invention, there is provided a method for manufacturing a packing made of a three-dimensional net-like structure which constitutes an internal structure of a device which performs material transfer, heat exchange or mixing between gases, liquids or gas and liquid, said internal structure being divided in a plurality of chambers or channels connected to one another and said three-dimensional net-like structure being formed by conversion and dispersion of four line elements, said method comprising steps of:
(A) disposing first line elements extending in parallel at a predetermined interval in a first direction on a plane and second line elements extending in parallel at a predetermined interval in a second direction which is different from the first direction on the same plane in such a manner that the first line elements cross the second line elements at a desired angle and the first and second line elements are laid one upon the other;
(B) fixing the first line elements to the second line elements at crossing points thereof and thereby forming a net;
(C) pressing the net to form a plurality of parallel undulating bulging portions which bulge at alternate ones of the crossing points continuously formed in the first direction and the second direction and thereby forming an undulating net;
(D) laying a second layer of the undulating net upon a first layer of the undulating net in such a manner that the crossing points continuously formed in the first direction and the second direction of the first layer of the undulating net alternately come into contact with and separate from the crossing points continuously formed in the first direction and the second direction of the second layer of the undulating net and thereafter fixing together the crossing points of the first layer of the undulating net and the second layer of the undulating net which are in contact with each other; and
(E) laying a third layer of the undulating net upon the second layer of the undulating net in such a manner that the crossing points continuously formed in the first direction and the second direction of the second layer of the undulating net alternately come into contact with and separate from the crossing points continuously formed in the first direction and the second direction of the third layer of the undulating net and thereafter fixing together the crossing points of the second layer of the undulating net and the third layer of the undulating net which are in contact with each other; and thereafter superposing a fourth, a fifth . . . and n-th (n being any integer) layer of the undulating nets in the same manner and fixing together the crossing points of the respective layers of the undulating nets and the immediately lower layers of the undulating nets which are in contact with each other.
According to the manufacturing method, a packing
1
as shown in the schematic perspective view of
FIG. 1
can be obtained. This packing
1
has, as shown in the partial perspective view of
FIG. 2
, has a unit structure
2
which is a combination of two quadruple pyramids which as a common base and apexes which are directed in the opposite directions. The three-dimensional net-like structure is formed by disposing a plurality of the unit structures
2
in vertical and horizontal directions. As will be apparent from
FIG. 2
, in this unit structure
2
, four line elements
3
constitute four sides of the respective quadruple pyramids and respective apexes
2
a
of the two quadruple pyramids and joints
2
b
of the two quadruple pyramids are formed by conversion and dispersion of four line elements. Accordingly, no element corresponding to the horizontal threads in the prior art X-packing is used at all in this unit structure
2
.
Accordingly, by using the packing
1
manufactured by the method of the invention in a device such as a gas-liquid contact device, liquid from a distributor flows in the direction of arrow B in
FIG. 1 and
, since no element corresponding to the horizontal threads is used in the packing
1
, the liquid which has fallen upon the top of the packing
1
does not produce a drift which is caused by flow of the liquid toward a laterally lower portion even if there is an error in installing the packing
1
in the device and, therefore, collection and downward redistribution of the liquid at the two vertical apexes
2
a
and joints
2
b
of the two quadruple pyramids of the unit structure
2
are performed uniformly.
For achieving the objects of the invention, there is also provided a method for manufacturing a packing made
Elve M. Alexandra
Hedman & Costigan ,P.C.
McHenry Kevin
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