利用 电伴热产品所产生的热量来补偿需伴热的管道等工艺装置所散耗的热量，以维持其相应的介质温度来满足工艺要求。所以正确计算出管道等工艺装置的热耗散量，对伴热所需的介质温度是至关重要的。为此在计算热耗散量前，必须先找出有关的几个重要参数：如TA（管道等介质维持温度）。TB（当地最低环境温度）、d（管道的外径）、do（管道内径）、δ（保温层厚度）。另外还需知道保温材料的名称和敷设环境（室内或室外、地面或埋地）。当知道了这些参数，再借助于有关的计算方式和表就能进行具体计算，从而得到所需的散热量。 管道及附件耗散热量的计算
确定管道的热耗散量
首先应知道管道的口径、保温层材料及厚度和所需维持温度之差△T，查管道散热量表，（乘以适当的保温系数），就能得到单位长管道的散热量，如果管子在室内则再乘以0.9。如果伴热的是塑料管道，因为塑料的导热性远低于碳钢（0.12:25），故可用0.6-0.7的系数对正常散热量加以修正。
例1：某厂有一管线，管径为1/2"，保温材料是硅酸钙，厚度10mm，管道中流体为水，水温需保持10℃，冬季最低气温是-25℃，环境无腐蚀性，周围供电条件380V、220V均有，求管道每米热损失？
步骤一：△T = TA - TB =10℃-（-25℃）=35℃
步骤二：查管道散热量表，管径1/2"。10mm保温层。
当△T =30℃热损失为11.0w/m，当△T =40℃热损失为14.9w/m，△T =35℃时，每米损失可采用中间插入法求得（因表中无QB值）。
QB=11.0w/m+（14.9w/m - 11.0w/m）[（35-30）÷（40-30）]=12.95w/m
步骤三：保温层采用硅酸钙，查保温材料修正数表乘以保温系数f及综合系数1.4
Qr=1.4QB×f=1.4×12.95w/m×1.50=27.195w
答案：管道每米损失热量27.195W
保温材料修正数表
|
保温材料 |
保温系数F |
导热常熟（w/m.k）10℃ |
|
玻璃纤维 |
1.0 |
0.036 |
|
岩棉（管壳） |
1.22 |
0.044 |
|
棉管壳 |
1.11 |
0.04 |
|
珍珠岩 |
1.31 |
0.047 |
|
聚氨酯泡沫塑料 |
0.67 |
0.024 |
|
聚苯乙烯泡沫塑料 |
1.86 |
0.031 |
|
硅酸钙 |
1.50 |
0.054 |
|
石棉绳 |
1.83 |
0.066 |
|
复合硅酸盐毡FHP-VB |
0.65 |
0.0234 |
|
硅酸铝耐火纤维板 |
1.0 |
0.036 |
确定管道阀体的散热量
闸阀散热量通常是相联口径管道每米热损失的1.22倍；如果是球阀，则可用0.7乘以闸阀热耗量，如果蝶型阀（节流阀），则乘以0.5；如果是浮式球阀，则乘以0.6。
从产品规格中可知电伴热带的工作电压，功率值。如算出单位长度热损失大于电伴热带单位长度的发热额定值，则可用以下方法来弥补：
● 采用卷绕法（如果用此法，则要先求出热损失对电伴热带发热功率的比值。如在2"管道上热损失是24w/m，而电伴热带功率20w/m，则比值=24/20是1.2倍，查电伴热带跨距表可知2"管道上间距为280mm的这种绕法能满足管道的热耗散。）
除上面的两种方法外，还可采取增加保温层厚度或采取导热系数较低的保温材料等附加措施弥补。
电伴热带跨距表（单位：mm）
|
管径 |
每米管子所需电伴热带数（比值） |
|
1.1 |
1.2 |
1.3 |
1.4 |
1.5 |
|
1″ |
229 |
152 |
102 |
102 |
76 |
|
5/4″ |
305 |
203 |
152 |
127 |
102 |
|
3/2″ |
330 |
229 |
178 |
152 |
127 |
|
2″ |
432 |
280 |
229 |
203 |
178 |
|
5/2″ |
508 |
356 |
280 |
229 |
203 |
|
3″ |
610 |
432 |
330 |
280 |
254 |
|
13/4″ |
711 |
483 |
381 |
330 |
280 |
|
4″ |
787 |
533 |
432 |
356 |
305 |
|
9/2″ |
889 |
610 |
483 |
406 |
356 |
|
5″ |
990 |
660 |
533 |
457 |
381 |
|
6″ |
1168 |
787 |
635 |
533 |
457 |
|
8″ |
1500 |
1041 |
838 |
711 |
610 |
电伴热带跨距表中保温材料是采用玻璃纤维为标准的，如用其字材料可参见保温材料修正表的系数进行修正，如前面例1所述。
为完善整个加热系统，还须考虑法兰，弯头及管道金属托架散热损失所需的电伴热带长度及预留供电电源接线用的长度，同时还要考虑预留供中间接线盒接线长度。法兰一般加上2倍的管径长度，弯头加上1.5倍的管径长度；管道金属托架加上3-5倍的管径长度，预留电源接线长度一般为1米，中间接线盒预留约0.5米。当计算出有关管道各附件的长度后，再加伴热管所需的电伴热带长度，我们就能得到整个系统所需电伴热带的总长度。
管道散热量表
|
保温厚度
mm |
温差℃
△T |
管道大小 |
15 |
20 |
25 |
32 |
40 |
50 |
65 |
|
内径mm |
1/2 |
3/4 |
1 |
5/4 |
3/2 |
2 |
5/2 |
|
英制(时)1/4
外径mm14 |
21 |
27 |
34 |
42 |
48 |
60 |
76 |
|
|
20 |
6.2 |
7.2 |
8.5 |
10.1 |
12.1 |
13.6 |
16.4 |
19.3 |
|
30 |
9.4 |
11.0 |
12.9 |
15.4 |
18.5 |
20.4 |
24.9 |
29.4 |
|
40 |
12.7 |
14.9 |
17.5 |
20.8 |
25.0 |
27.9 |
33.7 |
39.7 |
|
20 |
20 |
4.0 |
4.6 |
5.3 |
6.2 |
7.3 |
8.0 |
9.5 |
11.1 |
|
30 |
6.2 |
7.0 |
8.1 |
9.4 |
11.1 |
12.2 |
14.5 |
16.8 |
|
40 |
8.3 |
9.5 |
10.9 |
12.7 |
15.0 |
16.5 |
19.6 |
22.8 |
|
60 |
12.8 |
14.7 |
16.9 |
19.6 |
23.1 |
25.5 |
30.2 |
35.1 |
|
25 |
20 |
3.6 |
4.1 |
4.6 |
5.3 |
6.2 |
6.9 |
8.1 |
9.3 |
|
30 |
5.4 |
6.2 |
7.1 |
8.1 |
9.5 |
10.4 |
12.3 |
14.2 |
|
40 |
7.4 |
8.4 |
9.5 |
11.0 |
12.9 |
14.1 |
16.6 |
19.2 |
|
60 |
11.4 |
12.9 |
14.7 |
17.0 |
19.8 |
21.8 |
25.6 |
29.6 |
|
80 |
15.6 |
17.7 |
20.2 |
23.3 |
27.2 |
29.9 |
35.1 |
40.6 |
|
100 |
20.1 |
22.8 |
26.1 |
30.1 |
35.1 |
38.6 |
45.4 |
52.5 |
|
30 |
20 |
3.3 |
3.7 |
4.2 |
4.8 |
5.5 |
6.1 |
7.1 |
8.1 |
|
30 |
5.0 |
5.6 |
6.3 |
7.3 |
8.4 |
9.2 |
10.8 |
12.4 |
|
40 |
6.7 |
7.6 |
8.6 |
9.8 |
11.4 |
12.5 |
14.6 |
16.8 |
|
60 |
10.3 |
11.7 |
13.2 |
15.1 |
17.6 |
19.2 |
22.5 |
25.9 |
|
80 |
14.2 |
16.0 |
18.2 |
20.8 |
24.1 |
26.4 |
30.9 |
35.5 |
|
100 |
18.3 |
20.7 |
23.4 |
26.8 |
31.1 |
34.1 |
39.8 |
45.8 |
|
120 |
22.7 |
25.6 |
29.0 |
33.2 |
38.6 |
42.2 |
49.3 |
56.7 |
|
140 |
27.2 |
30.8 |
34.9 |
40.0 |
46.4 |
50.8 |
59.4 |
68.3 |
|
160 |
32.1 |
36.2 |
41.1 |
47.1 |
54.6 |
59.8 |
69.9 |
80.4 |
|
180 |
37.1 |
42.0 |
47.6 |
54.5 |
63.2 |
69.2 |
80.9 |
93.0 |
|
40 |
20 |
2.8 |
3.2 |
3.6 |
4.0 |
4.6 |
5.0 |
5.8 |
6.6 |
|
30 |
4.3 |
4.8 |
5.4 |
6.1 |
7.0 |
7.7 |
8.9 |
10.4 |
|
40 |
5.8 |
6.5 |
7.3 |
8.3 |
9.5 |
10.4 |
12.0 |
13.7 |
|
60 |
9.0 |
10.1 |
11.3 |
12.8 |
14.7 |
16.0 |
18.5 |
21.1 |
|
80 |
12.3 |
13.8 |
15.5 |
17.6 |
20.2 |
21.9 |
25.4 |
28.9 |
|
100 |
15.9 |
17.8 |
20.2 |
22.7 |
26.0 |
28.3 |
32.8 |
37.3 |
|
120 |
19.7 |
22.1 |
24.8 |
28.1 |
32.2 |
35.1 |
40.6 |
46.2 |
|
140 |
23.7 |
26.5 |
29.8 |
33.8 |
38.8 |
42.2 |
48.8 |
55.6 |
|
160 |
27.9 |
31.2 |
35.1 |
39.8 |
45.6 |
49.7 |
57.4 |
65.5 |
|
180 |
32.3 |
36.2 |
40.6 |
46 |
52.9 |
57.5 |
66.5 |
75.8 |
|
50 |
20 |
2.6 |
2.8 |
3.2 |
3.6 |
4.1 |
4.2 |
5.0 |
5.7 |
|
30 |
3.9 |
4.3 |
4.8 |
5.4 |
6.2 |
6.7 |
7.7 |
8.7 |
|
40 |
5.3 |
5.9 |
6.5 |
7.3 |
8.4 |
9.1 |
10.4 |
11.8 |
|
60 |
8.1 |
9.0 |
10.1 |
11.3 |
12.9 |
14.0 |
16.0 |
18.1 |
|
80 |
11.2 |
12.4 |
13.8 |
15.5 |
17.7 |
19.1 |
22.0 |
24.9 |
|
100 |
14.4 |
16.0 |
17.8 |
20.1 |
22.8 |
24.7 |
28.4 |
32.1 |
|
120 |
17.8 |
19.8 |
22.1 |
24.8 |
28.3 |
30.6 |
35.1 |
39.8 |
|
140 |
21.5 |
23.8 |
26.6 |
29.9 |
34.0 |
36.8 |
42.3 |
47.9 |
|
160 |
25.3 |
28.1 |
31.3 |
35.2 |
40.1 |
43.4 |
49.8 |
56.3 |
|
180 |
29.2 |
32.5 |
36.2 |
40.7 |
46.4 |
50.2 |
57.6 |
65.2 |
|
80 |
20 |
2.1 |
2.3 |
2.6 |
2.8 |
3.2 |
3.4 |
3.8 |
4.3 |
|
30 |
3.2 |
3.5 |
3.9 |
4.3 |
4.8 |
5.2 |
5.8 |
6.5 |
|
40 |
4.4 |
4.8 |
5.2 |
5.8 |
6.5 |
7.0 |
7.9 |
8.8 |
|
60 |
6.7 |
7.4 |
8.1 |
9.0 |
10.1 |
10.8 |
12.1 |
13.5 |
|
80 |
9.2 |
10.1 |
11.1 |
12.3 |
13.8 |
14.8 |
16.6 |
18.6 |
|
100 |
11.9 |
13.2 |
14.3 |
15.9 |
17.8 |
19.1 |
21.5 |
24.0 |
|
120 |
14.7 |
16.1 |
17.8 |
19.7 |
22.0 |
23.6 |
26.6 |
29.7 |
|
140 |
17.7 |
19.4 |
21.4 |
23.6 |
26.5 |
28 |
32.0 |
35.7 |
|
160 |
20.9 |
22.9 |
25.1 |
27.8 |
31.2 |
33.4 |
37.7 |
42.1 |
|
180 |
24.1 |
26.5 |
29.1 |
32.2 |
36.1 |
38.7 |
43.7 |
48.7 |
|
80 |
100 |
150 |
200 |
250 |
300 |
350 |
400 |
450 |
500 |
600 |
|
3 |
4 |
6 |
8 |
10 |
12 |
14 |
16 |
18 |
20 |
24 |
|
89 |
114 |
168 |
219 |
273 |
324 |
374 |
426 |
476 |
530 |
630 |
|
23.0 |
28.8 |
41.1 |
52.6 |
64.7 |
76.1 |
83.3 |
94.6 |
105.9 |
117.2 |
139.7 |
|
35.0 |
43.8 |
62.5 |
80.8 |
98.5 |
115.8 |
26.7 |
143.9 |
161.1 |
178.3 |
212.6 |
|
47.3 |
59.2 |
54.5 |
108.2 |
133.2 |
156.6 |
171.3 |
194.6 |
161.1 |
178.3 |
212.6 |
|
13.0 |
16.0 |
22.5 |
28.5 |
34.9 |
40.9 |
44.7 |
50.7 |
56.7 |
62.6 |
74.6 |
|
19.8 |
24.4 |
24.3 |
43.4 |
52.5 |
62.3 |
68.0 |
77.1 |
86.2 |
95.3 |
113.4 |
|
26.7 |
33.0 |
46.3 |
58.7 |
71.9 |
84.2 |
92.0 |
104.3 |
116.6 |
128.9 |
153.4 |
|
41.2 |
50.9 |
71.4 |
90.5 |
110.8 |
129.9 |
141.8 |
160.8 |
179.7 |
198.7 |
236.5 |
|
10.9 |
13.4 |
18.6 |
23.5 |
28.7 |
33.5 |
36.5 |
41.4 |
46.2 |
51.1 |
60.7 |
|
16.6 |
20.3 |
28.3 |
35.7 |
43.6 |
51.0 |
55.6 |
63.0 |
70.3 |
77.7 |
92.4 |
|
22.4 |
27.5 |
38.2 |
48.3 |
59.0 |
69.0 |
75.2 |
85.2 |
95.1 |
105.1 |
124.9 |
|
34.5 |
42.4 |
59.0 |
74.5 |
90.9 |
106.3 |
115.9 |
131.3 |
146.7 |
162.0 |
192.6 |
|
47.4 |
58.2 |
81.0 |
102.3 |
124.8 |
146.0 |
159.2 |
180.3 |
201.4 |
222.4 |
246.5 |
|
61.2 |
75.2 |
104.5 |
132.0 |
161.1 |
188.5 |
205.5 |
232.8 |
260.0 |
287.1 |
341.5 |
|
9.50 |
11.6 |
15.9 |
20.1 |
24.4 |
28.5 |
31.0 |
35.1 |
39.2 |
43.2 |
51.3 |
|
14.4 |
17.6 |
24.3 |
30.5 |
37.1 |
43.3 |
47.2 |
53.4 |
59.6 |
65.8 |
78.1 |
|
19.5 |
23.8 |
32.8 |
41.3 |
50.2 |
58.6 |
63.8 |
72.2 |
80.6 |
88.9 |
105.6 |
|
30.3 |
36.6 |
50.6 |
63.6 |
77.4 |
90.4 |
98.4 |
111.4 |
124.3 |
137.1 |
162.9 |
|
41.2 |
50.3 |
69.4 |
87.3 |
106.3 |
124.0 |
135.1 |
152.9 |
170.6 |
188.3 |
223.6 |
|
53.2 |
65.0 |
89.7 |
112.8 |
1377.2 |
160.2 |
174.5 |
179.4 |
220.3 |
243.1 |
288.7 |
|
65.9 |
80.4 |
111.0 |
139.6 |
169.9 |
198.3 |
216.1 |
244.4 |
272.8 |
301.1 |
357.5 |
|
79.3 |
96.8 |
133.5 |
168.0 |
204.4 |
238.6 |
259.9 |
294.0 |
328.1 |
262.1 |
430.1 |
|
93.3 |
113.9 |
157.2 |
197.7 |
240.6 |
280.8 |
306.0 |
346.1 |
386.2 |
426.3 |
506.2 |
|
108.1 |
131.9 |
182.0 |
228.9 |
278.6 |
325.2 |
354.2 |
400.7 |
447.1 |
493.5 |
586.2 |
|
7.6 |
9.2 |
12.6 |
25.7 |
19.0 |
22.1 |
24.0 |
27.4 |
30.2 |
33.3 |
39.4 |
|
11.6 |
14.1 |
19.1 |
23.9 |
28.9 |
33.6 |
36.6 |
41.3 |
45.9 |
50.6 |
60.6 |
|
15.7 |
19.0 |
25.9 |
32.3 |
39.1 |
45.5 |
49.4 |
55.8 |
62.1 |
68.5 |
81.1 |
|
24.3 |
29.3 |
39.9 |
49.8 |
60.3 |
70.1 |
76.2 |
86.0 |
95.8 |
105.6 |
125.1 |
|
33.3 |
40.2 |
54.8 |
68.4 |
82.7 |
96.2 |
104.6 |
118.0 |
131.5 |
144.9 |
717.7 |
|
43.0 |
52.0 |
70.8 |
88.3 |
106.8 |
124.2 |
135.1 |
152.4 |
169.8 |
187.1 |
221.7 |
|
53.3 |
64.4 |
87.6 |
109.3 |
132.3 |
153.9 |
167.3 |
188.8 |
210.3 |
231.7 |
274.5 |
|
64.1 |
77.4 |
105.4 |
131.5 |
259.1 |
185.1 |
201.2 |
227.1 |
252.9 |
278.7 |
330.2 |
|
75.4 |
91.1 |
124.1 |
154.8 |
187.3 |
217.9 |
236.9 |
267.3 |
297.7 |
328.1 |
388.7 |
|
87.3 |
105.5 |
143.7 |
179.3 |
216.9 |
252.2 |
274.3 |
309.5 |
344.7 |
379.9 |
450.1 |
|
6.5 |
7.8 |
10.5 |
13.1 |
15.7 |
18.2 |
19.8 |
22.3 |
24.7 |
27.2 |
32.2 |
|
9.9 |
11.9 |
16.0 |
19.9 |
23.9 |
27.7 |
30.1 |
33.9 |
37.6 |
41.4 |
48.8 |
|
13.4 |
16.1 |
21.7 |
26.9 |
32.3 |
37.5 |
40.7 |
45.8 |
50.9 |
56.0 |
66.2 |
|
20.7 |
24.8 |
33.4 |
41.4 |
49.9 |
57.8 |
62.7 |
70.6 |
78.5 |
86.3 |
102.1 |
|
28.5 |
34.1 |
45.9 |
56.8 |
68.4 |
79.3 |
86.1 |
96.9 |
107.7 |
118.5 |
140.1 |
|
36.7 |
44.0 |
59.2 |
73.4 |
88.3 |
102.4 |
111.1 |
125.1 |
139.1 |
153.0 |
180.9 |
|
45.5 |
54.4 |
73.3 |
90.9 |
109.4 |
126.8 |
137.6 |
154.9 |
72.2 |
189.5 |
224.0 |
|
64.4 |
77.2 |
103.9 |
128.7 |
154.9 |
179.5 |
194.9 |
219.4 |
243.9 |
268.3 |
317.2 |
|
45.5 |
54.4 |
73.3 |
90.9 |
109.4 |
126.8 |
137.6 |
154.9 |
72.2 |
189.5 |
224.0 |
|
54.7 |
65.6 |
88.2 |
109.3 |
131.6 |
152.2 |
165.5 |
186.4 |
207.2 |
227.9 |
269.4 |
|
64.4 |
77.2 |
103.9 |
128.7 |
154.9 |
179.5 |
194.9 |
219.4 |
243.9 |
268.3 |
317.2 |
|
74.6 |
89.4 |
120.3 |
149.0 |
179.4 |
207.9 |
225.6 |
254.0 |
282.4 |
310.7 |
367.2 |
|
4.8 |
5.7 |
7.4 |
9.0 |
10.7 |
12.3 |
13.3 |
14.9 |
16.4 |
18.0 |
21.1 |
|
7.3 |
8.6 |
11.3 |
13.7 |
16.3 |
18.7 |
20.2 |
22.6 |
25.0 |
27.4 |
32.1 |
|
9.9 |
11.6 |
15.2 |
18.5 |
22.0 |
25.3 |
27.3 |
30.6 |
33.8 |
37.0 |
43.5 |
|
15.3 |
17.9 |
23.5 |
28.6 |
34.0 |
39.0 |
42.1 |
47.1 |
52.1 |
57.1 |
67.0 |
|
20.9 |
24.6 |
32.2 |
39.2 |
46.6 |
53.5 |
54.8 |
64.7 |
71.5 |
78.3 |
92.0 |
|
27.0 |
31.8 |
41.6 |
50.6 |
60.2 |
69.1 |
74.6 |
83.5 |
92.3 |
101.2 |
118.8 |
|
33.5 |
39.3 |
51.1 |
62.7 |
74.5 |
85.5 |
92.4 |
103.4 |
114.3 |
125.3 |
147.1 |
|
40.3 |
47.3 |
62.9 |
75.4 |
89.6 |
102.9 |
11.2 |
124.4 |
137.5 |
150.7 |
176.9 |
|
47.4 |
55.7 |
72.9 |
88.8 |
105.5 |
121.1 |
130.9 |
146.4 |
161.9 |
177.4 |
208.3 |
|
54.9 |
64.5 |
84.4 |
102.8 |
122.2 |
140.3 |
151.5 |
169.5 |
187.5 |
205.4 |
241.2 | | 
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