Dalton Electric - The Leader in Cartridge Heating Technology  
Dalton Electric - Manufacturer of Watt-Flex Cartridge Heaters and Diff-Therm Platen Heaters Dalton Cartridge Heaters Dalton Diff-Therm Platen Heaters Dalton Electric News About Dalton Contact Dalton Site Map  
 
Electric Heating Co., Inc
      
The Watt-Flex
Advantages:
  Maximize Heat Transfer
  Last 5 times longer
  Ease of Removability
  Uniform Temperature Profile
  Higher Watt Densities and Operating Temperatures
  Use in Oversized Bores
  Hot-Tip Option
  External Thermocouple
Product Data
  Cartridge Heater Sizes
  Immersion Heaters
  Accessories and Modifications
  Pricing
Technical Data
  Engineering Data and Design Considerations
  Literature / Downloads

Process Heating Engineering Data
and Application Design Considerations

The following reference information can assist you in the selection of Watt-Flex heaters for new process heating designs. For a consultation on any heating application, call our heating engineers at 978-356-9844.

  Heating Metal Parts
  Calculate Process Heating Wattage Requirements
  Physical Properties of Materials Table
  Heating Liquids

Heating Metal Parts

The required wattage for a metal heating application is equal to the sum of watts required for material heat up plus watt loss during heat-up, plus a 20% safety margin added for contingencies.

To calculate the heater capacity needed to produce a required level of heat, find the thermal values in the Physical Properties of Materials Table and plug them into the following equations:

 

 Wattage Loss Rates Chart: This chart shows rates at which convection watt loss as function of surface temparature. It is used to calculate wattage requirements for process heating of metals.
 

Calculation of Required Wattage

C = (A + B)*1.2

where A = Watts for material heat-up
where B = Watts Heat Loss during heat-up
where C = Total Watts Required
     
  A =

[Weight of Material (lbs.)] x [Specific Heat] x [Temperature Rise (F)]

    3.412 x Heat up Time (hours)
     
  B = [Watt Loss per sq. in.] x [Area (sq.in)]
   

Physical Properties of Materials

Substance

Specific Heat
Heat of Fusion
Lowest melting point
Density 
Thermal conductivity
Thermal Expansion
 
Btu/lboF
 Btu/lboF
 oF
 lb/ft3
  lb/in3
 Btu/hr/
ft2/oF/ft
 inches per inch per  oF x 10-6
Aluminum 1100
.24
169
1190
169
.098
128
13.1
Aluminum 2024
.24
167
935
173 
.100
112
12.9
Aluminum 3003
.24
167
1190
170 
.099 
112
12.9 
Antimony
.052
69
1166
423 
.245 
10.9
4.7 - 6.0 
Brass
.10
- 
1700±
525 
.304 
56
11.1 
Carbon
.204 
 -
6700
- 
.080 
13.8
.3 -> 2.4 
Copper
.10 
91 
1981
550 
.318
224
9.2 
Glass
.20
 -
2200±
165 
.096 
.45 
5 
Graphite
.20
 -
 
130 
.075
.104
- 
Incoloy800
.12
 -
2475
501 
.290
8.1
7.9
Inconel 600
.11
 -
2470
525 
.304
9.1
7.4 
Invar
.13
 -
2600
508 
.294
6.1
0.6 
Iron, Cast
.13
 -
2300±
450 
.260
33
6.5 
Iron, wrought
.12
 -
2800±
480 
.278 
36
6.5 
Lead, solid
.031
10 
621
710 
.411
20
16.3
Lead, melted
.04
- 
 -
665 
.385
 -
 -
Magnesium
.232
160
1202
109 
.063 
91
14
Monel 400
.11
 -
2370 
551 
.319 
14
7.7
Nickel 200
.11
133 
2615
554 
.321
39
7.4
Nichrome
(80% Ni, 20% Cr)
.11
- 
2550 
524 
.303
8.7
7.3 
 Solder
(50%Pb, 50%Sn)
.04
17 
415
580
.336 
26
13.1 
Steel, mild carbon 
.12
- 
2550±
490 
.284 
38
6.7
Steel,stainless 304 
.11
- 
2550
488 
.282
8.8
9.6
Steel,stainless 430 
.11
 -
2650
475 
.275
12.5
6.0
Tin, solid 
.056
25 
450
455 
.263 
36
13
Tin, melted 
.064
-
 -
437 
.253
18
 -
Type Metal
(85% Pb, 15% Sb)
.040
15 
500
670 
.388 
 -
- 
 Zinc
.095
51
787
445 
.258
65
9.4 - 22

Heating Liquids

Consideration should be given to the following factors when heating liquids with Watt-Flex Cartridge heaters.

  • Locate heater wells in an unrestricted space in the main body of the liquid.
  • The heated section of the well should be covered by liquids at all times.
  • In metal-melting applications, explosions can result unless pressure is vented during melting phase of heat-up.
  • Certain watt-density limits exist in immersion applications. Please consult the factory for technical assistance.
 

home | cartridge heaters | immersion heaters | vacuum diffusion pump heaters
contact us | about dalton

 


Dalton Electric Heating Co., Inc (978)356-9844
28 Hayward Street Ipswich, MA 01938 USA

(C) Copyright 2003. Dalton Electric Heating Co, Inc. All Rights Reserved.

<