Pipe joints or couplings – Elbow
Reexamination Certificate
2000-05-04
2002-07-23
Browne, Lynne H. (Department: 3629)
Pipe joints or couplings
Elbow
C285S131100, C285S132100, C285S133110
Reexamination Certificate
active
06422608
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an anti-abrasion pipe fitting for high-speed particle-laden flow.
BACKGROUND ART
Generally, a material feeding pipe is used for feeding a certain powder material such as fly ash, bottom ash, etc. in an industrial facility such as a fossils electric power plant, a steel fabrication factory, a cement fabrication factory, and the like. In these cases, as a feeding method, a wet feeding method is known for mixing water with a powder material in a slurry form and feeding the mixed slurry. As another feeding method, a dry feeding method is known for feeding a powder material using a mechanical force or pneumatic pressure.
In the wet feed method, since a certain material is fed based on its weight, a small amount of force is used, and a small abrasion occurs at an inner wall of a curved coupling pipe, so that its life span is increased. However, after the material is fed, the slurry is compressed by a filter press, etc. and is dehydrated. Namely, in this case, a process is additionally required, so that a related facility becomes bulky, and the area for installing the bulky system is increased. In particular, a polluted water containing heavy metals may be produced, so that an environment may be polluted during a cooling process.
In addition, in the dry feeding method, since a post-process is not required, the system may be simplified, and the fabrication cost is minimized. However, lots of power is required for feeding powder materials, and an abrasion is increased at an inner wall of a coupling pipe, so that a maintenance cost is increased.
In the case that a powder material containing a burned lime is mixed with water, the volume of the burned lime is sharply increased for thereby resulting in an explosion of the burned lime. Therefore, in this case, the dry feed method is generally used.
The conventional curved coupling pipe for a high speed powder material feed pipe will be explained.
FIG. 23
is a view illustrating a conventional 90 elbow
100
which includes an upper side straight portion
101
, a lower side straight portion
102
which is perpendicular to the upper side straight portion
101
, and a flow direction changing portion
103
connecting the upper side straight portion
101
and the lower side straight portion
102
.
The upper side straight portion
101
, the lower side straight portion
102
, and the flow direction changing portion
103
have the same diameter. The center line C of the upper side straight portion
101
and the lower side straight portion
102
has a radius curvature of a ¼ circle.
The movement of the powder material in the conventional elbow
100
will be explained. At the center portion, the flow speed of the upper side straight portion
101
is fast, and is gradually decreased in the direction of the pipe inner wall. At the flow direction changing portion
103
, the flow speed at the outer side curved portion
103
a
is fast, and the flow speed at the inner side curved portion
103
b
is slow, so that a high speed zone H is formed at an inner wall side of the outer side curved portion
103
a
, and a low speed zone L is formed at an inner wall side of the inner side curved portion
103
b
. At the lower side straight portion
102
, the flow speed is fast at the center portion, and is decreased in the direction of the pipe inner wall side, so that the flowing amount and flow speed at the upper side straight portion
101
and the lower side straight portion
102
are same.
Here, assuming that the flow speed of the powder material at the upper side straight portion
101
is 35 m/sec(2100 m/min), the flow speed at the high speed zone H is 45 m/sec(2700/min), and the flow speed at the low speed zone L is 15~25 m/sec(900~1500/min).
Therefore, in the outer side curved portion
103
a
of the flow direction changing portion
103
of the elbow
100
having the high speed zone H, a collision of the powder materials which are linearly moved from the upper side straight portion
101
occurs. In addition, a great abrasion occurs due to a friction with the fed powder material and a decreased anti-abrasion due to a heat generated at an inner wall of the pipe.
The anti-abrasion occurs due to the heat generation at the inner wall of the pipe. In detail, the temperature of the powder material reaches about 80 C. When the above-described powder materials are fed, the inner wall of the powder material feed pipe is heated. In particular, the heat is generated due to the temperature of the powder material and a friction with the powder materials at the outer side curved portion
103
a
of the flow direction changing portion
103
, so that the anti-abrasion characteristic of the pipe wall is decreased.
Next, the abrasion due to the collision and friction of the powder materials will be explained. Since a high speed zone H is formed at the outer side curved portion
103
a
of the flow direction changing portion
103
, an abrasion due to a collision with the powder materials occurs.
Here, the degree that the flow speed and pressure at the high speed zone H of the powder materials fed in the high speed powder material feed pipe affects the abrasion will be compared with those of a grinding process.
The polishing speed(the sum of the circular speed of the grinding wheel and the relative moving speed of the grinding wheel and an object) of the grinding wheel used for the grinding process is 2200~3400 m/min, and the grinding pressure is 0.50~0.7 kg/cm
2
, and the feeding amount of one time is maximum 5_ when the grinding process is performed using a cooling water. As a result, the MOS hardness of the powder material is 5.5~6.5. Assuming that the flow speed at the upper side straight portion
101
is 2100 m/min, since the flow speed at the high speed zone H is 2700 m/min, an abrasion is increased due to a collision and friction of the powder materials at the inner wall of the pipe at the high speed zone H.
In the case of the dry feed method, since water is not provided, the abrasion is increased compared to the grinding process in which a cooling water is provided.
In addition, since the abrasion at the outer side curved portion
103
a
of the flow direction changing portion
103
does not uniformly occur. Namely, as shown in
FIG. 23
, an erosion zone EZ is formed at the portion in which the abrasion occurs at an initial stage. The abrasion is performed at this portion as faster as the other portions by 2.0
6
times.
The frequent maintenance of the powder material feed pipe is required due to the above-described abrasion. In order to perform the maintenance, since the operation of the system is stopped, much economic loss occurs.
As shown in
FIG. 24
, the 45 elbow includes a lower side straight portion
202
which is formed at an angle of 45 with respect to the upper side straight portion
201
and the upper side straight portion
201
, and a flow direction changing portion
203
connecting the upper side straight portion
201
and the lower side straight portion
202
.
The above-described 45 elbow
200
includes a certain flow direction changing angle between the upper side straight portion
201
and the lower side straight portion
202
which is different from the 90 elbow
100
and includes a high speed zone H formed at the outer side curved portion
203
a
of the flow direction changing portion
203
and a low speed zone L formed at the inner side curved portion
203
b
. The abrasion is sharply increased at the high speed zone H by the above-described reasons.
As shown in
FIG. 25
, the T-shaped coupling pipe
300
includes a first upper side straight portion
301
, a lower side straight portion
303
formed on the same axis as the first upper side straight portion
301
, and a second upper side straight portion
302
which is perpendicular to the first upper side straight portions
301
and
303
.
An upper side flow direction changing portion
304
is formed between the first upper side straight portion
301
and the second upper side straight portion
302
. A lower side flow direction changing portion
305
is form
Han Jean Gean
Kim Dong Won
Kim Jerng Dong
Kim Youn Je
Kwon Dong Goo
Browne Lynne H.
Dong Lim Industrial Co., Ltd.
Dunwoody Aaron
LandOfFree
Anti-abrasion pipe fittings for high-speed particle-laden flow does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Anti-abrasion pipe fittings for high-speed particle-laden flow, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Anti-abrasion pipe fittings for high-speed particle-laden flow will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2865740