dg component strip and ring heaters

8/11/2019 DG Component Strip and Ring Heaters

1/6

Components

A-56

Strip & Ring Heaters Applications& Features

Up to 72" Lengths

Up to 3,000 Watts

120 - 480 Volt

Up to 38 W/In 2

Maximum Sheath Temp.

Rust-Resisting Iron 750F

MONEL 900F

Chrome Steel 1200F INCOLOY 1500F

Accessory Clamping Devices,Optional

Applications

Chromalox strip heaters are used principallyfor convection-type air heating and clamp-oninstallations. When selecting strip heatersfor either, two important factors must beconsidered:

1. The proper sheath material for resistingany rusting and oxidizing inherent in theprocess or environment and for withstand-ing the sheath temperature required.Standard sheath materials are rust-resisting iron, chrome steel and INCOLOY (type NS only). Stainless Steel andMONEL sheaths are available.

2. The watt density of the element, or wattsper square inch of heated area, should below for heating asphalt, molasses andother thick substances with low heattransferability. It can be higher for heatingair, metals and other heat-conductingmaterials. (See Technical section fordetermining allowable watt densities.)

When high operating temperatures areneeded, watt density must be limited inorder not to exceed the maximum sheathtemperature. Watt density is given in thetable for each strip heater.

In general, a viscous material with low thermalconductivity requires a low watt density.High watt densities can be used with thinnerliquids and with materials of high thermalconductivity. Premature loss of the elementdue to excessive temperature may result if thematerial's heat-take-away ability is low. Also,the material may be charred, carbonized or itschemical makeup altered by overheating.

Features

Choice of Sheath Materials capable of operat-ing up to 1500F sheath temperature to heatvarious processes economically. These includerust-resisting iron (750F), chrome steel(1200F), Monel (900F), and INCOLOY (1500F).Refractory Insulated Construction exclusively.By far the most rugged and best for long,dependable service.

More Types and Ratings More precisematching to your power service and work loadrequirements. Special ratings and sizes can bemanufactured readily.

More Stocked Models Hundreds of modelsin stock and available for immediate shipment.

Lengthwise and Cross Section Curving Available only on made-to-order productsfor efcient heat transfer. Strip and ring heat-ers can be factory formed to t the shape ofthe surface to be heated.

Easy Installation Chromalox clampingdevices and mounting tabs speed installation.

More Choices of Strip Heater Terminal Loca-tions To simplify wiring layout betweenelements and power lines.

Many Additional Features Available toadapt heaters to suit special applications

made-to-order.Installations Minimum maintenance costs.

Controls are Part of the Total ChromaloxPackage for your heating job, regardless of itstype or the temperature precision you need.Refer to the Controls section.

High Quality, Coiled Alloy Resistor Wire isuniformly spaced over the width and lengthof the strip heater to assure even heatdistribution.

Resistor Wire is Embedded in speciallyformulated, high-grade refractory mate-rial which both insulates the resistor andtransfers heat rapidly to the sheath.

Refractory is then Compressed to Rock-Hardness and high density under tremen-dous hydraulic pressure to maximize heattransfer from coil to sheath. Elements areoven cured at high temperatures to semi-vitrify and mature the refractory.

Maximum Heat Transfer, from the instantthe element is rst energized, is providedby the high emissivity black oxide nish. El-ements with shiny surfaces do not transferheat as well.


2/6

Components

A-5

Installation Guidelines Chromalox strip elements, in most cases, canbe applied with standard hardware. However,for rm contact and best heat transfer, stocked

Chromalox clamps are recommended.Note Heat insulating material should notbe placed against the sheath of the heatingelement

Utility Clamps Utility Clamps secure strip elements to atsurfaces or surfaces with large radii such aslarge tanks. Threaded studs are welded tosurface, heaters are positioned, then clampsare bolted down. Where more than one clampis used, tighten nuts and then back off 1/2 turnto allow for expansion.

Strip & Ring HeatersSelection & InstallationGuidelines Utility Clamps

Milled Plates

Clamping Bands

Oven Mounting

Oven Mounting Oven Mounting Application of strip ele-ments to ovens may be made simply withthe use of welded-on studs and secondaryinsulation bushings. Mounting holes in tabsare slotted to allow for expansion. Refer toModications in this section.

Milled Plates Milled Plates allow heaters to be held in posi-tion in platens and similar objects with a steelplate recessed to heaters width, thickness andpositions, then screwed to the working plateor surface.

Clamping Bands Clamping Bands can be used to rmly fastenstrips longitudinally to large diameter cylindricalsurfaces.

Connecting Lead Wires Should be nickel-plated copper, nickel or alloy. Copper will oxi-dize and loosen connections. Do not use copperterminal lugs. See Accessories in this section.

Utility Clamps

Milled Plates

Clamping Bands Oven Mounting

Selection Guidelines

Product tobe Heated

TemperatureDesired

for ProductsSheath

Material

ProductTemp.(F)

AllowableWatt Densit

(W/In2)SolidsMolds, Platens, Dies,Pipes, Tanks

Up to 1400FClamp-On Applications

Rust-Resisting Iron 560150

38

Chrome Steel 850700400

71015

INCOLOY 1 200750

110013501400

2820

83

2.5Air & GasesFree Air Velocity-1 ft/sec.

Up to 1400FBracket Mounted

Rust-Resisting Iron 500100

38


71015

INCOLOY 1

1400400 334Free Air Velocity-4 ft/sec.

Up to 1400FBracket Mounted

Rust-Resisting Iron 500 3250 8


71015

INCOLOY 1 1400600

534

Note: 1CSA Only


3/6

Components

A-58

Fahnestock Terminals Fahnestock Terminals Type S only. Forquick temporary connections where ambienttemperatures do not exceed 150C. Maximumrecommended amperage is 7.5 Amps.

Strip & Ring HeatersModications

Special Lengths Type PT, SE, SN and SNHonly. Special lengths are made-to-order forinstances in which the amount of heat appliedto a surface is critical and standard lengths are

not suitable.Special Voltage and Wattage All types.Certain highly specialized applications mayrequire special ratings. However, most can behandled with standard heaters or standard rat-ings applied on an alternate voltage. Contactyour Local Chromalox Sales ofce.

Special Wattage Distribution All types ex-cept TH. When even temperatures are requiredand end losses may cause an unsatisfactorytemperature drop near the edges, additionalwattage can be provided at each end of thestrip to make up for losses.

Lengthwise Bending Lengthwise Bending for clamping around pipes

or cylindrical vessels. Terminals may be locatedinside or outside of curvature for all types listed.

3" Min. Inside Radius Type S, SE, OT PT,TH, NH, SNH, SN and ST.

6" Min. Inside Radius Type SSE, SSEM,SSNH and SSNHM.

4-3/4" Min. Inside Radius Type WS.

Cross-Section Curving Cross-Section Curving Type SE only, forclamping strips to 2, 2-1/2, 3, 4, 6, 8 and 12"pipes. For larger size pipe, use at strips. Radiiavailable 1-3/16, 1-7/16, 1-3/4, 2-1/4, 3-5/16,4-5/16 and 6-5/16" and 8-3/4. Terminalsoutside only.

1-1/21/2

9/16

1

Special Length Terminals All types. Where ashorter or longer terminal bolt than standard shownin drawing is needed, indicate length needed.

Rubber-Molded Terminals Rubber-Molded Terminals Type NS only. Used generally in low temperature applica-tions where moisture, condensation and highhumidity are considerations. Available in neo-prene-rubber (to 190F). Longer cold end orlower wattage is required to assure tempera-ture limit of molding material is not exceeded.End opposite terminal is welded closed.

Special Lead Wire TerminalConstruction Special Lead Wire Terminal Construction All types. Specied most often when clear-ance is unavailable for standard terminals andwhen lead wires are more suitable for wiringto nearby components.

Secondary Insulation Bushing Secondary Insulation Bushings All Typesexcept NS. Must be used when strips aremounted for air heating only or when con-nected in series on line voltages 480V orabove. Note To accommodate bushings,

a 17/32 x 11/16" diameter mounting hole intabs should be specied for heaters. To Order Specify PCN 255716 (includes bushing andhardware for one strip) and quantity.

Dual Contact Surface Type SE only. 53-7/8"maximum A dimension. Flush-top constructiongives good contact for all surfaces of the stripheater. Ideal for use in machined slots andinstalling between two smooth metal surfaces.

Without Mounting Tabs

Without Mounting Tabs All types. Permitsinstalling more heat in a given conned space.Specify without mounting tabs whenordering this feature.

Extra Strong Mounting Tabs All types ex-cept WS. Recommended when strips are bentlengthwise and tabs are used for bolting.

Monel Sheath Type S, SE, OT, PT, HSPand WS.

Stainless Steel Sheath All types.

Cover for Seamless Strips, FactoryWelded

Cover for Seamless Strips with Threaded

Opening for Conduit Cover is welded toheater. Specify position of threaded openingeither on top of cover, or as shown. Type SSE,SSEM and SSNHM.

Lengthwise Bending

Cross-Section Curving


4/6

Components

A-59

Porcelain Beads

Bead SizeDimensions (In.) Wire Size

SolidNo. Beads

Per Ft.No. Beads(Pieces) PCNA B C

23456

0.170.20.260.330.4

0.0680.0920.1560.1240.156

0.170.20.260.330.4

14 B&S12 B&S

8 B&S10 B&S

8 B&S

8869514538

4,5352,9001,500

650360

263880263900263927263943263960

To Order Specify PCN and quantity.

Protective Terminal Covers

Shims

Ceramic Post TerminalInsulators

Porcelain Hi-Temp Insulation

Strip & Ring Heaters Accessories

Protective Terminal Covers Types OT,PT, SE, WS and Seamless Types SSE, SSEM,SSNH and SSNHM. Helps guard termi-nals from spillovers, dripping. Removable

sheet-metal cover, with Bx tting, is shippedseparately.

ModelDimensions (In.)

A B COT-AC-1 2 2-1/2 2-1/2PT-AC-1 1-7/8 1-1/8 1-3/4SE-AC-1 1 2-1/16 1-1/2 2

1. Used on type WS (mounted sideways).

Protective Terminal Covers

PT-AC-1 (PCN 255724)

C

A

B

OT-AC-1 (PCN 129242)

A

CB

SE-AC-1 (PCN 256727)

C B

A

Shims

A B

C

Porcelain Hi-Temp Insulation Porcelain Hi-Temp Insulation For insulating buss bars spec. 51 porcelain

insulators 1/2 L x 13/16" W with 1/8 x 9/16"slot. 95 pieces per lb.

To Order Specify pounds, PCN 269780 anporcelain insulators.

For Insulating Bare Wires Two typesavailable:

1. Porcelain Tubing 3/8" O.D. x 1/8" I.Dx 6" L (may be broken for shorter lengths)Suitable for 10-gauge or smaller; 8-gaugtakes No. 6 porcelain bead.

To Order Specify quantity and PCN 2638

2. Porcelain Beads Listed in table belowCan be used when wiring does not permistraight tubing.

3. When selecting porcelain beads forstranded wire, use next larger gauge wireand use bead for that size (i.e., 10 gaugestranded wire requires a No. 6 bead).

Shims Shims Types OT, PT, S, SE and TH. Providesame advantage as ush-top construction

and can be used with stock heaters. Shimsare 0.031" thick, 29/32" wide and lengths to theater.

Porcelain Tubing

Porcelain Beads

Ceramic Post Terminal Insulaters Ceramic Post Terminal Insulators All typesexcept NS and SN. Use with insulated wire tohelp protect against electrical shock. Wirescan leave terminal at any angle.

PCN 259805 (Nickel plated steel hardware)PCN 255732 (Stainless steel hardware)

Cap

Wave Spring

Skirt

Ceramic Post Terminal Insulators


5/6

Components

A-60

High Temperature (Bare) Wire

Strip & Ring Heaters Wire & Accessories(contd.)

High Temperature (Bare) Wire

Insulated Wire

Buss Bar

Silicone Boot Termination Kit

Silicone Boot Termination Kitwith Thermostat

Buss Bar

Wire & Buss Bar

High-temperature wire and buss bar are rec-ommended for connections to heater terminalsand for runs in heated zones. When ambienttemperature exceeds maximum allowed forinsulated wire, use bare wire or buss bar withporcelain insulators. Current-carrying capaci-ties should be carefully noted.

Buss bar is solid or perforated to facilitatewiring, especially when terminals are in line.Perforated buss bar, has 11/32 x 7/32" slotson 7/16" centers. When connecting elementswith buss bar, provide expansion loopsbetween elements. Buss bars may be used inmultiples for higher ampacity (approx.33-1/2% per buss bar) than listed above,center.

Ambient Temperature Corrections forInsulated Wires Multiply ampacity values,in tables below, by the following correctionfactors to determine current-carrying capacityat higher ambient temperatures.

Silicone Boot Termination Kit

SBK The silicone boot termination kitprovides electrical insulation for strip heaterterminals and leads with ring type insulatedconnector on one end for bringing power tothe strip heaters.

Silicone Boot Termination Kitwith Thermostat

SBKT The silicone boot termination kit withthermostat used with strip heaters providesan inexpensive way to maintain temperaturein control cabinets, panels and other small en-closures. In this application, strip heaters areused to prevent freezing and corrosion, and tocontrol humidity in enclosures with humiditysensitive electronic components.

Insulated Wire

SBKT

Model PCNTemperature (F)Closes Opens

SBKT-1 386011 38 53SBKT-2 386020 60 75SBKT-3 386038 105 120SBK 121890 N/A N/A

AmbientTemp. Nickel-Plated

Copper TeonInsulated

Nickel

SiliconeGlass

TeonGlass

MGS-MicaGlassC F

305060708090

100120140149177204232260269300

86122140158176194212248284300350400450500550572

0.980.950.930.90.870.850.790.720.650.580.490.35

0.970.940.90.870.830.790.710.610.50.35

0.980.950.930.90.870.850.790.720.650.580.490.35

1.361.221.1210.870.7

Note After exposure to high tempera-tures, all wire insulation becomes brittleand will not withstand repeated exing.

SizeAWG

Solid/SStrand/F

Amp-acity1

Nom.O.D. Model PCN

550F Max. Wire Temp.Nickel-plated Copper, Uninsulated1410

8

SSS

417093

.064

.102

.128

CSB-14CSB-10CSB-8

263839263812263804

1000F Max. Wire Temp.Manganese-Nickel, Uninsulated1414121210

FSFSS

1212151520

.075

.064

.097

.081

.102

AFB-14ASB-14AFB-12ASB-12ASB-10

269317269309269296269288269261

To Order Specify PCN and quantity.

SizeAWG

Solid/SStrand/F

Amp-acity1

Nom.O.D.

Insul In. Model PCN392F Max. Wire Temp. Type A Nickel WireSilicone Rubber Treated Glass BraidInsulated 600V UL Listed16 F 27 .224 3-CFI-16 26375916 S 27 .224 3-CSI-16 26374014 F 36 .237 3-CFI-14 26373214 S 36 .237 3-CSI-14 26372412 F 45 .263 3-CFI-12 26371612 S 45 .263 3-CSI-12 26370810 F 60 .29 3-CFI-10 26369510 S 60 .29 3-CSI-10 263687

482F Max. Wire Temp. Type TGT,Nickel-plated Copper, Tefon ImpregnatedGlass Braid Insulated 600V UL Listed14 F 39 .121 6-CFI-14 26379114 S 39 .112 6-CSI-14 29539812 F 54 .141 6-CFI-12 26378312 S 54 .13 6-CSI-12 29540010 F 73 .17 6-CFI-10 26377510 S 73 .156 6-CSI-10 2954198 F 93 .212 6-CFI-8 263767

482F Max. Wire Temp. Tefon Tape andSilicone Impregnated Glass BraidInsulated 600V UL Listed14 F 39 .121 3-AFI-14 269253

12 F 54 .141 3-AFI-12 26923710 F 73 .17 3-AFI-10 269210

842F Max. Wire Temp. Nickel-cladCopper, MGS-Mica Glass Insulated 600V16 F 33 1 .065 6-CFIM-16 29535514 F 44 1 .102 6-CFIM-14 29536312 F 55 1 .118 6-CFIM-12 295371

To Order Specify PCN and quantity.1. See note 1 in Buss Bar Table.2. These wiring recommendations are

general in nature. Confrm actual wiresize and selection in accordance withNEC (National Electrical Code).

Buss BarMonel

DIM (In.) Amp-acity1 PCNWidth Thick

700F Max. Wire Temp.Solid

0.50.5

.032

.0641828

346124346132

Perforated Slot Size = 7/32 Dia.0.50.5

.032

.0649

16346140346159

To Order Specify PCN and numberof feet.

1. These current values will cause theconductor to operate at 100F abovesurrounding ambient. Values may also beused for bare wire with porcelain tubes orbead insulation. Monel max. limit is 800F.


6/6

Components

A-61

Strip & Ring Heaters Accessories (contd.)

Element Clamps

Cast-iron clamps, for use with Chromaloxstrip and ring elements, retain their strengthat elevated temperatures to assure maximumsheath-to-surface contact. Resulting uniformefcient heat transfer from internal resistancewire to the heated material minimize hot spotson the element, contributing to long service life.

Element Clamps

Mounting Studs

Clamp 6018 Usually used in sets of two ormore to clamp ring elements to at surfaces.5/16" athead machine screws are normallyused with head brazed or welded to worksurface (PCN 263978).

Mounting Studs

Mounting Studs For use with Chromaloxclamps. For all clamps except No. 6933, studare 5/16 18 x 1-1/2" Monel (PCN 12784steel washer (PCN 127853), Monel nut(PCN 127861). For No. 6993 clamp; studs ar

5/16" 18 x 2" Monel (PCN 127837).Installation Fasten studs to the worksurface by welding, brazing or threading. Uscorrect size stud to t clamp. See Selection &Installation Guidelines in the Components setion. For temperatures over 750F, stainlesssteel studs are recommended.

Note When tightening nuts, torsion shoulnot exceed 10 foot pounds maximum. Heatemust be allowed to expand. One center clamshould hold heater. Nuts on other clampsshould be backed off approximately 1/2 turn allow for heater expansion.

5/16" Dia.Stud Hole

3-1/23/8

Clamp 6018

3-3/8

5" Min. Rad.

15/16

3/8" Dia.Stud Hole

4

Clamp 6933 Use to clamp two strip heaterson 3" centers using 3/8" studs at 5" intervals(PCN 263644).

Clamp 6933

Clamp 5970 Use to clamp three stripheaters on 2" centers using 5/16" studs at 5"intervals (PCN 263652).

5/16" Dia. Stud Hole

5" Min. Rad.

5/8

1-1/2

2 5

1-1/2

3

Clamp 5970

Clamp 5971 Use to clamp two strip heaterson 2" centers using 5/16" studs spaced 5"apart (PCN 263636).

3

5/16" Dia. Stud Hole

5" Min. Rad.

11/16

3

Clamp 5971

dg component strip and ring heaters

Documents