怎样把9.4米的heat trace Run在1.4 米的3寸管子上？

jack_lai

+ S! a& ~6 k" t$ q8 u6 KHow to run 9.4 meters heat trace on a normal 3 inch pipe which is 1.4 meter long. 今天上班碰到一个问题。怎样把9.4米的heat trace Run在1.4 米的3寸管子上？
) Y6 J& F3 g( N# a/ w% ^Detail:
The length of the heat trace is 22 meters.
/ p/ x9 ]$ k; q1 y7 G& c; sAfter running heat trace through six valves. The rest of the heat trace is 9.4 meters.  
5 e- f5 V! s7 v7 T7 Z4 LThese 9.4 meters heart trace can be run through the 1.4 meter 3 inches pipe ?

xdf

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, ?* X# B( n+ Q1 d) c! W, {在回答你的问题前，请问一下：
前面的十几米是按要求的长度（尤其在阀门上，shoe上）铺设的吗？
; c- B# y  B( ~2 \& \你的情况，是前面安装不妥，造成后面Cable太多，不符合设计要求，你需要重新按要求安装，而不是简单的挤一下。
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从目前看，可能性：1。原来安装的不妥，重新安装
                  2。用错了TRACE，找到正确的，重新安装
                  3。设计失误，重新设计，ORDER，重新安装

xdf

如果简单回答你的问题，3“管 要安 6个passes 不是不可能，要看radius

jack_lai

3# xdf
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Thank you for your analysing. I agree it is designed problem. But What foreman concern is “can you finish ?”  Anyway it is possible. Today we figured it out. Today the soccer is worth to watch. we can talk about this question later

jack_lai

1# jack_lai

足球看完了来看看题目。
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+ @7 N! Z1 [/ z4 |8 |$ y( rThe length of the heat trace is 22 meters. The size of the heat trace is 5/16 inch (WATTS/ m SUPPLIIED is 43.7)
The drawing is shown as figure 1. (All data is from the memory.  They are not the same as the real drawing, but a little bit different)
We can see it is not easy to install the 22 meters heat trace according as figure 1
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As a normal question we just discuss:
7 @+ F0 T! O: W. }1 Z( _" sHow do you run these 9.4 meters heat trace (size 5/16 inch) on the 3 inches 1.4 meters pipe ?
/ F+ R; s0 r1 Q6 o) ~% II call this is JACK LAI Spiral Method 螺旋法
The outside circumference of the 3 inch pipe is more than 10 inches.  See figure 2.
% D) B' K' l2 ?$ A+ Z2 RThere are 10 positions to plac the heat trace. They are 0.1,2,3,,,,,9.  The distance between each position--heat trace is about one inch.
Because the pipe is horizontal, position 0 can not be placed. See figure 2
# s. N' T) o6 q, r5 Z' t3 iBecause the maximum bend radius of the heat trace is 2 inches( see note 1),  position 5 can not be placed. See figure 2. Then the route of the heat trace can be like figure 3
& y) h. ?6 _' j7 B3 i; CThe total heat trace that can be installed here is about
1.4 * 6 + 1 * 2 = 8.6 + 2 =10.8 Meters
So, the 9.4 meters heat trace can be installed along the 3 inched 1.4 meters pipe without a problem.

Note :
/ S# X; `$ d$ F0 M) b! [) h, @1. The minimum bend radius:
  X* D2 o2 t4 i2 c% P" EBecause the heat trace size here is 5/16,  6 times the outside diameter of the heat trace is
5/16 *6 = 30/16 almost = 2 inches
So the maximum bend radius is 2 inches.
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) s. Y& V( H& o8 i# `6 ~# {2 @Summary
2 M8 @5 V5 s* U2 i0 OAs regular
3 W0 ~' V+ J: ~4 w3 r: ?6 tFor 3 inch pip: If heat trace size is 5/16 inch, and no RTD, the box position is close to the end of pipe. 1 meter long pipe
if the pipe is horizontal, The length of heat trace can be installed is about
1 * 9 = 9 meters
$ V1 m6 @( [4 a" a4 jIf the pipe is vertical, The length of heat trace can be installed is about
' Z2 E8 F, x" |7 t8 n1 * 10 = 10 meters.
For 2 inch pipe: If heat trace size is 5/16 inch, and no RTD, the box position is close to the end of pipe. 1 meter long pipe
0 [# F+ v0 E% y) X9 k3 r$ l, W9 {if the pipe is horizontal , The length of heat trace can be installed is about
1 * 4 = 4 meters
If the pipe is vertical, The length of heat trace can be installed is about
7 V! t( Z; `: o2 D2 a1 * 5 = 5 meters.

jack_lai

5# jack_lai
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"if the pipe is horizontal, The length of heat trace can be installed is about
1 * 9 = 9 meters
* e3 V, C4 }* V9 z$ |4 a* C5 |$ GIf the pipe is vertical, The length of heat trace can be installed is about
1 * 10 = 10 meters. "
$ J4 i! Y4 I  ^) g2 I8 ]- `' r应该改成
if the pipe is horizontal, The length of heat trace can be installed is about
/ [8 E) \' C; m. y& ^, O9 A) Y. h# N1 * 8 = 8 meters
If the pipe is vertical, The length of heat trace can be installed is about
$ \4 A9 P! ?1 W2 X, t7 L, c7 R; H6 _3 w1 * 9 = 9 meters.
1 U1 c) ^; o/ _( z& {" G- l" K如果你把heat trace 的间距再调小些，上面的公式有可能成立.

www5www

Good job!
Another way, you can put the extra trace on the 3' valve if it have room.
The last way, you can burn(install) the extra trace on next pipe which connected to your pipe.

pierrelu2001

建议问现场的manufacture 它们最权威,,, 别自己做主,,,这条trace 有问题...

pierrelu2001

or ask QC guy