Pipes and tubular conduits – Flexible – Corrugated
Reexamination Certificate
1999-10-01
2001-02-13
Brinson, Patrick (Department: 3752)
Pipes and tubular conduits
Flexible
Corrugated
C138S144000, C138S121000
Reexamination Certificate
active
06186182
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a double-walled spiral pipe for the use of a drainage. More particularly, the present invention relates to a double-walled spiral pipe which can prevent a damage or breakage thereof by a flexibility of the inner wall in case that the outer wall is deformed.
BACKGROUND OF THE INVENTION
A spiral pipe has been widely used as a drainage in order to drain sewage, buried under the ground. A conventional spiral pipe has a spirally corrugated shape, and the structural strength thereof is good against load and impact. But, there is a disadvantage such that sewage can not be drained smoothly through the conventional spiral pipe due to the corrugations. In order to solve the shortcomings of the conventional spiral pipe, a spiral pipe with double walls has been developed.
As shown in
FIG. 1A
, a conventional spiral pipe is composed of an outer wall
1
which is prepared by winding spirally a steel plate
1
a
having corrugations
1
b
to thereby have a cylindrical configuration and an inner wall
2
having a cylindrical configuration, which contacts with the wave bottom of the corrugations of the outer wall
1
. In a double-walled spiral pipe, the outer wall
1
having corrugations functions as a structure to resist against load and soil pressure, and the inner wall
2
having a plane surface, which is united with the wave bottom of the outer wall
1
along the inner surface of the corrugated spiral pipe. Therefore, the inner wall
2
functions to smoothly flow a sewage therethrough, and also a solid structure and an improved drainage capacity thereof can be expected.
As shown in
FIG. 1B
, in case that corrugations of the outer wall
1
are deformed due to load, soil pressure or heat, a pitch of corrugations of the spiral pipe can become wide or narrow, therefore a tensile force or compressive force are given to the inner wall
2
. Relatively, the inner wall
2
having a poor resistance to a tensile force or compressive force can be easily damaged and also detached from the outer wall
1
.
Also, since a corrugated surface
1
b
of the outer wall
1
is deformed depending upon heat, the inner wall
2
is repeatedly contracted and elongated. Therefore, a junction portion between the wave bottom of the corrugations of the outer wall
1
and the inner wall
2
can be broken.
As illustrated in above, the conventional double-walled spiral pipe has shortcomings that the outer wall can be easily deformed depending upon a sectional load and soil pressure, thereby the durability of the spiral pipe is reduced, and a sewage can not be drained smoothly through the inner pipe of the spiral pipe due to the deposit which is caused by the inflow of impurities or soil, and the inner wall can be damaged and detached from the outer wall depending upon heat.
OBJECTS OF THE INVENTION
An object of the present invention is to provide a double-walled spiral pipe which can prevent the breakage or damage of the inner wall by active contraction and elongation, and also can lengthen the life span thereof.
Another object of the present invention is to provide a double-walled spiral pipe which can smoothly drain a sewage therethrough.
These and other objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawing to which they relate.
SUMMARY OF THE INVENTION
A double-walled spiral pipe in accordance with the present invention is composed of an outer wall
10
having a cylindrical shape, which is prepared by means of winding spirally a coated steel plate
11
having corrugations
12
; and an inner wall
20
having a cylindrical shape, which is contacted with the wave bottom of corrugations of said outer wall
10
, and can contracted or elongated depending upon a change of the pitch of the corrugations of said outer wall
10
.
The inner wall
20
having a cylindrical configuration is installed to be contacted with the wave bottom of corrugations of the outer wall
10
, and functions to drain a sewage, etc. The inner wall
20
has a semi-circular portion
22
a
at the point of the wave bottom of the corrugations
12
of the outer wall, and a plane surface
22
b
is formed between the semi-circular portions
22
a
. Accordingly, although corrugations
12
of the outer wall
10
can be easily deformed depending upon a sectional load or soil pressure or heat, by which a pitch of the corrugations
12
can be wide or narrow, the semi-circular portion
22
a
of the inner wall
20
is flattened, thereby the inner wall
20
is prevented from a damage or breakage caused by outer factors.
REFERENCES:
patent: 2898941 (1959-08-01), Kilcup
patent: 3330303 (1967-07-01), Fochler
patent: 4487232 (1984-12-01), Kanao
patent: 5058934 (1991-10-01), Brannon
patent: 5548093 (1996-08-01), Sato et al.
patent: 5727599 (1998-03-01), Fisher et al.
Brinson Patrick
Seongho CSP., Ltd.
Vigil Thomas R.
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