鲜花( 0) 鸡蛋( 0)
|
楼主 |
发表于 2010-7-10 17:18
|
显示全部楼层
本帖最后由 jack_lai 于 2010-7-10 18:52 编辑
' B x+ w/ ~" @1 O, R0 }0 J, M# e0 U, V: B" b8 \, G1 t- X
1# jack_lai 2 D4 x: `: ]5 O
& N0 |0 D9 w: V# W4 u5 U足球看完了来看看题目。
/ Y5 K6 n6 c$ E6 _8 N2 ~% ]3 a$ N. J, L/ N. r
The length of the heat trace is 22 meters. The size of the heat trace is 5/16 inch (WATTS/ m SUPPLIIED is 43.7)% s! w6 t/ Q! w2 @9 ?# Q2 r
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)
2 V: z9 `8 i9 nWe can see it is not easy to install the 22 meters heat trace according as figure 17 v1 N [0 W' P# s# H% Z b6 h
' z: i; i" o# a7 b' I2 o$ O8 }$ \
9 v9 s- l5 _) x4 f. \' D4 Z
* ^8 }$ B9 p, L; c+ I9 v8 o
+ R" V6 D1 Q: R4 {/ ?2 iAs a normal question we just discuss:
/ f% Z: o7 z: o1 GHow do you run these 9.4 meters heat trace (size 5/16 inch) on the 3 inches 1.4 meters pipe ?
! B# f! y0 T; ]- f2 h, M" cI call this is JACK LAI Spiral Method 螺旋法5 Q% d. Q# h# h+ @, ^' |& ]
The outside circumference of the 3 inch pipe is more than 10 inches. See figure 2.
! ?( O% B4 v% O0 hThere 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. 1 u V0 _( T9 `- f9 @% C
Because the pipe is horizontal, position 0 can not be placed. See figure 2* B* j# h: R/ S
Because 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 35 N! P7 r6 n! e- O
The total heat trace that can be installed here is about ; h& E% i# U9 O) |7 x8 d
1.4 * 6 + 1 * 2 = 8.6 + 2 =10.8 Meters+ a7 M( v% v) z/ G& N
So, the 9.4 meters heat trace can be installed along the 3 inched 1.4 meters pipe without a problem.
& F! x2 J1 x* A' H% }: e4 E: } ]. M4 @5 x5 I
Note :* U8 b* \ ?7 h- M
1. The minimum bend radius:
6 e& i4 S* p" b, P0 S0 `Because the heat trace size here is 5/16, 6 times the outside diameter of the heat trace is7 r$ y3 r1 z" I) d# s5 ]* N, n
5/16 *6 = 30/16 almost = 2 inches
3 i, E1 l6 v1 \" G2 \So the maximum bend radius is 2 inches.6 e( F1 i; w S* A
( E" l5 G. W0 Z
! o) u* K o I$ p9 x
+ i' U7 }/ \+ ^4 f+ N/ p
Summary
; B" u# N- M2 @3 I" l+ [0 NAs regular
0 c1 b F2 }* d9 v, w$ |: H$ ^For 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, |- v! r4 V6 m3 g& ?2 X- \
if the pipe is horizontal, The length of heat trace can be installed is about
* c4 Y( i5 g" M1 * 9 = 9 meters
3 @: U8 x- k/ t2 {- KIf the pipe is vertical, The length of heat trace can be installed is about% O8 z) b9 e2 ~( l: K
1 * 10 = 10 meters. 5 d8 t# {3 E6 n* F9 G* v1 X* f
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
3 X4 X$ J9 J! I& P( v4 w7 r+ Oif the pipe is horizontal , The length of heat trace can be installed is about
' T+ H# |1 g/ y+ P- `1 * 4 = 4 meters
0 m1 M1 H4 Z4 L/ M5 q+ F# K) qIf the pipe is vertical, The length of heat trace can be installed is about
Q5 U b, j! Z+ [6 }6 T1 * 5 = 5 meters. |
|