Cartridge & Immersion Heaters

 

SUPERWATT® HIGH WATT CARTRIDGE HEATERS HIGH WATT DENSITY

Superwatt High Watt Cartridge Heaters
Description

U.L. Recognized – E56973
C.S.A. Certified – 016386-0-000

Cartridge Heaters: Superwatt High Watt Density In-Stock

Application

Dies, Heat Sealing, Hot Melt Adhesive, Plastic Molding, Platens, Shoe Machinery.

Features
  • Elements are designed for maximum: Watt density, temperature, heat transfer, and heater life.
  • The useful life of a cartridge heating element is determined by how quickly the heat generated in the resistance wire can be dissipated to the outside sheath. With low and moderate watt density elements, such as Backer Hotwatt’s standard line, the conventional method of inserting helical coils in formed ceramics is an entirely satisfactory method of construction because the wire temperature relative to sheath temperature even though considerably higher, is still well within safe long-life operating temperatures.
  • The Superwatt cartridge heater accelerates the transfer of heat from the resistance wire to the sheath. This is accomplished by relocating the wire so that it is closer to the sheath; and swaging the outside diameter of the heater, thereby compressing the magnesium oxide filler so that it becomes an improved conductor of heat from the wire while maintaining its dielectric properties. (See diagram below). By improving the heat transfer rate, it is possible to manufacture elements of higher densities because the differential between the wire temperature and the sheath temperature has been minimized.
  • Long, trouble free service.
  • Made in U.S.A
Construction
Superwatt High Watt Cartridge Heater Illustration
  1. Heliarc welded end seal.
  2. Series 300 stainless steel sheath of precision dimensions and tolerances for intimate, stable, non-oxidizing contact with cavities machined for them.
  3. Pure magnesium oxide compressed to an optimum density for best heat transfer and electrical insulation at elevated temperatures.
  4. Element wire situated in close proximity to outside surface for maximum heat transfer and minimum internal temperature while preserving good dielectric qualities.
  5. Ceramic cap.
  6. Fiberglass insulated leads.

 

Lengths between or longer than those listed may be ordered.

Diameter: 1/8″ (.124/.120)

Maximum Amperage: 3.5 Not UL/CSA

Sheath

Length

Cat.No.

Min.

Watts

Max.

Volts

1″

HS12-1

CONSULT FACTORY

1 1/2″

HS12-1.5

CONSULT FACTORY

2″

HS12-2

CONSULT FACTORY

2 1/2″

HS12-2.5

50

120

3″

HS12-3

60

120

3 1/2″

HS12-3.5

70

120

4″

HS12-4

80

120

Diameter: 1/4″ (.249/.245)

3/8″ (.374/370)

1/2″ (.499/495)

Maximum Amperage: 4

6

10

Sheath

Length

Cat.No.

Min.

Watts

Max.

Volts

Cat.No.

Min.

Watts

Max.

Volts

Cat.No.

Min.

Watts

Max.

Volts

1″

HS25-1

70

120

HS37-1

70

120

1 1/2″

HS25-1.5

70

120

HS37-1.5

80

120

HS50-1.5

110

240

2″

HS25-2

100

120

HS37-2

120

240

HS50-2

160

240

2 1/2″

HS25-2.5

130

120

HS37-2.5

160

240

HS50-2.5

210

240

3″

HS25-3

150

240

HS37-3

200

240

HS50-3

270

240

3 1/2″

HS25-3.5

180

240

HS37-3.5

240

240

HS50-3.5

330

240

4″

HS25-4

210

240

HS37-4

280

240

HS50-4

380

240

4 1/2″

HS25-4.5

240

240

HS37-4.5

320

240

HS50-4.5

430

240

5″

HS25-5

260

240

HS37-5

360

240

HS50-5

490

240

5 1/2″

HS25-5.5

290

240

HS37-5.5

400

240

HS50-5.5

550

240

6″

HS25-6

320

240

HS37-6

440

240

HS50-6

600

240

6 1/2″

HS25-6.5

350

240

HS37-6.5

480

240

HS50-6.5

650

240

7″

HS25-7

380

240

HS37-7

520

240

HS50-7

700

240

7 1/2″

HS25-7.5

410

240

HS37-7.5

560

240

HS50-7.5

750

240

8″

HS25-8

440

240

HS37-8

600

240

HS50-8

800

240

8 1/2″

HS25-8.5

470

240

HS37-8.5

640

240

HS50-8.5

850

240

9″

HS25-9

500

240

HS37-9

680

240

HS50-9

900

240

9 1/2″

HS25-9.5

530

240

HS37-9.5

720

240

HS50-9.5

950

240

10″

HS25-10

560

240

HS37-10

760

240

HS50-10

1000

240

10 1/2″

HS25-10.5

590

240

HS37-10.5

800

240

HS50-10.5

1050

240

11″

HS25-11

620

240

HS37-11

840

240

HS50-11

1100

240

11 1/2″

HS25-11.5

650

240

HS37-11.5

880

240

HS50-11.5

1150

240

12″

HS25-12

680

240

HS37-12

920

240

HS50-12

1200

240

Red catalog number denotes stock item. See stock section for specific ratings.

Diameter: 5/8″ (.624/.620)

3/4″ (.749/.745)

1″ (999/.993)

Maximum Amperage: 20

28

30

Sheath

Length

Cat.No.

Min.

Watts

Max.

Volts

Cat.No.

Min.

Watts

Max.

Volts

Cat.No.

Min.

Watts

Max.

Volts

1 1/2″

HS62-1.5

130

240

2″

HS62-2

200

240

2 1/2″

HS62-2.5

270

240

HS75-2.5

330

240

HS1.0-3

475

240

3″

HS62-3

340

240

HS75-3

410

240

HS1.0-3

475

240

3 1/2″

HS62-3.5

410

240

HS75-3.5

495

240

HS1.0-3.5

570

240

4″

HS62-4

480

240

HS75-4

575

240

HS1.0-4

665

240

4 1/2″

HS62-4.5

550

240

HS75-4.5

660

240

HS1.0-4.5

760

240

5″

HS62-5

620

240

HS75-5

740

240

HS1.0-5

855

240

5 1/2″

HS62-5.5

690

240

HS75-5.5

825

240

HS1.0-5.5

950

240

6″

HS62-6

760

240

HS75-6

910

240

HS1.0-6

1045

240

6 1/2″

HS62-6.5

830

240

HS75-6.5

980

240

HS1.0-6.5

1140

240

7″

HS62-7

900

240

HS75-7

1075

240

HS1.0-7

1235

240

7 1/2″

HS62-7.5

970

240

HS75-7.5

1150

240

HS1.0-7.5

1330

240

8″

HS62-8

1040

240

HS75-8

1240

240

HS1.0-8

1425

240

8 1/2″

HS62-8.5

1110

240

HS75-8.5

1325

240

HS1.0-8.5

1520

240

9″

HS62-9

1180

240

HS75-9

1400

240

HS1.0-9

1615

240

9 1/2″

HS62-9.5

1250

240

HS75-9.5

1475

240

HS1.0-9.5

1710

240

10″

HS62-10

1320

240

HS75-10

1560

240

HS1.0-10

1805

240

10 1/2″

HS62-10.5

1390

240

HS75-10.5

1645

240

HS1.0-10.5

1900

240

11″

HS62-11

1460

240

HS75-11

1730

240

HS1.0-11

1995

240

11 1/2″

HS62-11.5

1530

240

HS75-11.5

1820

240

HS1.0-11.5

2090

240

12″

HS62-12

1600

240

HS75-12

1890

240

HS1.0-12

2185

240

14″

HS62-14

1740

240

HS75-14

2050

240

HS1.0-14

2545

240

16″

HS62-16

1880

240

HS75-16

2210

240

HS1.0-16

2920

240

18″

HS62-18

2020

240

HS75-18

2370

240

HS1.0-18

3300

240

20″

HS62-20

2090

240

HS75-20

2450

240

HS1.0-20

3675

240

Red catalog number denotes stock item. See stock section for specific ratings.

Obtaining maximum heat transfer and long life

Fit

High watt density heaters require careful fit to insure optimum performance and long life. Backer Hotwatt recommends that installation holes not be drilled and reamed over .002 larger than the nominal hole size required. The heaters are sized so that they never exceed .005 less than the nominal diameter and always at least .001 under the nominal diameter for a slide fit. These close fits insure rapid heat transfer from the heater and also help keep the unit as cool as possible, which contributes to long life.

Cycling

Rapid cycling of heaters from very low to very high temperatures shortens their life considerably. It is recommended therefore, that care be taken to compute the correct wattage for any given installation. Optimum wattage should result in a 50/50 off/on cycle. For very high temperature operation (over 750°F), off/on control might well be replaced by input voltage regulation through variable transformers or silicon rectifiers so that great temperature fluctuations in the heater wire are minimized.

Location of temperature control point

When thermostats are used, the sensing element ought not to be placed further than 1/2″ away from the heater wherever possible. Location further away could conceivably cause the unit to run too hot and thereby shorten life.

Wattage

Minimum wattage is based on 60 watts per square inch. Units with lower watt densities may be manufactured for special conditions such as high temperature or vibration. Minimum wattage available can be determined using the following formula and the values in Table 1:

minimum watts

Table 1: Maximum allowable Ohms per inch by diameter

 

Superwatt Diameter

Maximum Ohms per Inch of Heater Length

1/8″

500

1/4″

600

3/8″

800

1/2″

600

5/8″

500

3/4″

400

1″

300

Voltage

Standard voltage is either 120V or 240V. Other voltages are available.

Termination

All units up to 1″ diameter, within published amperage limits, are manufactured with 6″ (type SF1) leads. 1″ diameter units are manufactured with 6″ (type SF2). Longer length leads are available. Stock units supplied with 12″ leads.

 

Graph A: Maximum watts/sq.in. with various increasing temperatures and hole tolerances.

watts per square inch graph

Hole size over nominal fractional size
The watt densities are based on a unit installed in mild steel. Different materials affect the above values

 

i.e. the lower the thermal conductivity of the material, the lower the maximum allowable watts per square inch.

Formula for determination of allowable element wattage:

Element Wattage: 3.142 x Diameter x Heated Length x
Maximum watts/square inch from Graph A.

Formula for determination of watts/sq.in:
watts per square inch formula
Tolerances

Wattage tolerances is +5% -10% at rated voltage. Length tolerances are ± 2% with a ± 1/16″ minimum. Length tolerances apply to element sheath length.

Camber tolerances for units up to 12″ long is .005″ per six inch length. For units over 12″ long,
tolerance is .020″ per foot of length. This value varies as the square of the length in feet.(i.e. – A 36″ unit has a camber tolerance of .020″ x (3)² = .180″). Normally camber does not present a problem since the unit will flex enough to fit into a straight, close fit hole.

How To Order

After determining the wattage required and the line voltage available: determine the physical space available for heaters and the number of heaters required.
Review Stock list for In-Stock Items.
Review Special Features.

 

Specify: Catalog number, wattage, voltage, lead type, and special features if required.
Example: HS37-4.25/375W/120V/SF1-18/SF26.