●How is your resistancewire sized?
●What grade ofmagnesium oxide isbeing used?
●How is your cold pinattached to yourresistance wire?
●What is your standardelement diameter?
●Do you passivatestainless steel heaters?
●Do you repress U-bendswhen required?
●Do you use terminalsealant as a standard?
●How are your elementsfixed to the screw plug?
●Are screw plug hex andthreads to industrystandards?
●Do you provide a standardthermowell?
●Is the terminal housingrotatable?
●Do you have a standardgrounding lug?
●Are your heaters UL listedand CSA certified?
●What quality assurancetesting is done on yourfinished products?
●Can you ship out ofstock in 24 hours andprovide assembly stockproducts in 5 days?
●Can you provide me experttechnical assistance whenneeded?
PDS QUALITY
www.chromalox.com ©1998 Wiegand Industrial Division
8
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On first impression, various manufacturers of screw plug immersionheaters appear to be all alike; but when you take a closer look at screw plugimmersion heaters, it becomes evident that considerable differences exist.The following information will help to explain the differences in constructionof Chromalox screw plug immersion heaters compared to other manufacturers.It will also describe Chromalox’s third party listing program, quality testing,and delivery capabilities.
Before buying a screw plug heater, you should ask the manufacturerquestions to insure you are getting a quality heater that will last in yourapplication. Below, you will find a list of some of these important questions.
Screw Plug Immersion Heatersinclude one, two or three hair-pin bent tubular element(s)joined to a threaded hex plug.Screwed into tank walls,this UL Listed / CSA Certifieddirect contact heat source heatsliquids, viscous fluids, forced airand gases with maximumenergy efficiency. In addition,elements can be bent into manyconfigurations to suit a varietyof applications. Most screw plugheaters come with a thermowell(for temperature control sensor)and a completely wired terminalenclosure for electrical connec-tion. Certain models availablewith a patented 360° rotatablescrew plug housing to facilitateeasy conduit connections. Selectfrom a variety of sheath materi-als, element lengths, plug sizesand ratings from 0.5 kW and up,for 120 to 600 volts.
DifferencesAmong
Screw PlugImmersion
Heaters
http://www.chromalox.com
Basic Construction
Element Diameter
Stainless Steel HeatingElement Surface Finish
Chromalox® standard 0.475” Diameter
10% more surface area than0.430” diameter typical of competitors
Results in longer life and loweroperating temperature
0.475”
Pickling & PassivationRemoves most carbon particles
���������
Elements
Thermowell
Rotatable TerminalHousing
Hex Threads
Resistance Wire-Computer Designed for correct gauge wire
MetallicSheath
CompactedMagnesium OxideInsulation
Solid ColdPin Junction
Hex
Elements InternalConstruction
Quality - Differences Among Screw Plug Immersion Heaters
Chromalox connects the resistance wire to the cold pin with a weld. This provides asolid electrical connection that better withstands thermal cycling. Some manufac-turers press or braze the cold pin onto the resistance wire, making failure due tothermal cycling more common. Ask the heater manufacturer how they maketheir cold pin connections. Chromalox uses only high purity magnesium oxideinsulation to insure good dielectric resistance between the resistance wire and themetal sheath. In addition, Chromalox uses a rolling method to reduce the diameterand compact the MgO refractory. Other manufacturers often use lower grades ofMgO, and swage versus rolling down the element diameters, causing inferiordielectric properties which can lead to a less reliable heater. By utilizing highgrade materials and having controlled manufacturing processes, good thermalconductivity is achieved and a longer life heating element is produced. Ask theheater manufacturer how they compact element refractory.
Chromalox® www.chromalox.com
Corrosion is often accelerated by a poor surface finish. Proper surface finish ofstainless steel heating elements is very important to prevent corrosion. Duringtypical heater manufacturing processes, steel dies and rollers come intocontact with the element sheath, and as a result, carbon steel particles areembedded into the surface of the element. If not removed, pitting and corro-sion will occur, eventually leading to premature heater failure. As standardpractice, Chromalox pickles and passivates stainless steel heaters by soakingthe elements in an acid bath. This process removes the carbon steel particlesfrom the surface of the heating element and prolongs heater life. Othermanufacturers will only passivate for an extra charge. Ask the heatermanufacturer if passivation is a standard practice.
Although Chromalox makes elements that range from 0.315” to 0.475” indiameter, our standard 2” and 2-1/2” NPT screw plug immersion heaterelements are 0.475” in diameter. Other manufacturers have standardized on0.430” diameter elements to reduce costs. For an equivalent immersion length,the 0.475” diameter heating element provides 10% more surface area versus a0.430” diameter element. The greater the surface area, the lower the heaterwatt density and lower its operating temperature. Lower operating tempera-tures result in longer heater life. Ask the heater manufacturer whatdiameter elements they supply as standard.
The basic construction of an immersion heater includes the terminal housing,standard NPT screw plug, thermowell and heating elements. If you take acloser look at the construction of a heating element, you will find the heart ofthe heater is the resistance wire. Chromalox’s resistance wire is computerdesigned in order to select the correct gauge wire for the required heatingelement wattage and voltage. Many manufacturers use limited sizes of wire,and may not choose the optimal wire for the application. Ask the heatermanufacturer how they determine resistance wire dimensions.
http://www.chromalox.com
Welded Stainless/Steel Elements
Terminal Seal Types
Elements U-Bends
Air gapsin Mgo
Electricalshortto sheath
RecompactsMgo
Removesanyair gaps
Silicone - Fluid, Resin, RTV200°F to 300°F continuous exposureModerate moisture barrier
Epoxy200°F continuous exposureGood moisture barrier
HermeticUp to1000°F sheath temperatureThe only true seal
Minimizes corrosionat element attachment
Solder not a goodcorrosion resistant material
Prevents leakageinto terminal enclosure
Elements U-Bends -Repressed
Quality - Differences Among Screw Plug Immersion Heaters
Most screw plug immersion heater elements are bent in a U-bend configura-tion. When bending a heating element on a tight radius, air gaps can occur inthe magnesium oxide insulation within the element bend. Air gaps can permit adielectric (insulation) breakdown to occur, and cause an electrical short to themetal sheath of the heater.Chromalox represses U-bends to recompact the MgO and remove any air gaps,which ensures dielectric integrity. Many manufacturers do not repress bends tosave time and money. Ask the heater manufacturer if they repressU-bends when necessary.
Heating element refractory can absorb moisture from the air, and if enoughmoisture is absorbed, high leakage current could occur during start-up.Chromalox screw plug immersion heaters contain heating element terminalsealant as a standard feature. A terminal sealant inhibits moisture from beingabsorbed by the heating element refractory.There are several optional types of terminal sealants to suit the particularapplication. Ask the heater manufacturer about terminal sealants beforemaking a purchase decision.
Chromalox stainless steel, INCOLOY® and carbon steel elements are welded tostainless and carbon steel screw plugs. A welded element provides superiorcorrosion protection and element attachment. Some manufacturers brazeelements to the screw plug without concern for the heaters intended applica-tion. In heating a corrosive fluid, braze material is susceptible to being chemi-cally attacked by the fluid. A welded-in element prevents corrosive fluidleakage into the terminal housing which can lead to heater failure. Ask theheater manufacturer how they secure their elements to the screw plug.
Chromalox® www.chromalox.com
http://www.chromalox.com
Thermowells
Hex and Threads
Hex and Threads -Other Supplier Alternatives
Wide hex fitsstandard tools
Long threadsfortighter fit
Easy to install
Standard to acceptsensing bulbs
Integral and remotethermostat options
IT DOESTHETWIST
Unique with360 DegreeRotation Feature
Rotatable TerminalHousing
Differences Among Screw Plug Immersion Heaters - Quality
Short hex requiresspecial tools
Short threadssusceptible todamage
Short threadscause loose fitinto tank
Difficult to install
Chromalox®
www.chromalox.com
Chromalox heater design provides a screw plug hex and threads that are userfriendly. Wide hex and generous threaded lengths allow standard tools to beused and allows a secure fit.Other manufacturers often provide a narrow hex, making the hex difficult togrip, potentially damaging the screw plug threads, or short thread lengths thatmay not provide a tight seal. Chromalox screw plug immersion heaters are easyto install — no special tools are required. Ask the heater manufacturer iftheir Hex and Threads meet industry standards.Chromalox stainless steel and steel screw plugs come with a standard solid hexand threads. Others use stamped, cast or hollow plugs and threads that can failunder higher pressures.
The NEMA 1 terminal enclosure of the Chromalox screw plug heater is fullyrotatable. This patented feature allows 360° rotation of the terminal enclosure(270° rotation for heaters with thermostat). Thus, you are able to rotate theenclosure (housing) to face the electrical conduit connection after the heaterhas been properly installed.During installation, it is preferred that the conduit for the wiring be in a downposition. This prevents any moisture that may accumulate on the conduit fromrunning down into the terminal enclosure of the heater and cause potentialheater failure. No other heater manufacturer offers this feature.
Chromalox screw plug immersion heaters can be provided with or without anintegral thermostat. Regardless, a thermowell is standard on most heaters toaccept the sensing bulb of a thermostat. This allows an easy retrofit if later youlearn that a thermostat is necessary. Most manufacturers charge extra forthermowells. Ask the heater manufacturer if a thermowell is standard.
http://www.chromalox.com
Differences Among Screw Plug Immersion Heaters - Quality
Electrical Grounding
Third Party Listing
Quality Testing
Most Extensivein the Industry
UnderwritersListing (UL)
Canadian StandardsAssociation (CSA)
NationalElectrical CodeRequirement
ChromaloxStandard
Ground lugsnot providedby all suppliers
100% HydrostaticPressure Test forWeld Leaks
100% Resistance Checkfor Element Wattage
Insulation ResistanceCheck for Moisture20 Megohms or greater
Dielectric Hi-pot Check
UL®
Chromalox’s stocking program is unequaled in the industry. Our distributionwarehouse can ship stock heaters within 24 hours of receipt of an order.Chromalox has over 1,000 different screw plug heaters in stock. In addition,most of our assembly stock products can ship within 5 days. And, we offer 10day shipment for many of our other thousands of pre-engineered designs. Wealso provide a toll free service number for replacement part orders and installa-tion assistance. 1-800-368-2493. Ask the heater manufacturer abouttheir delivery times and stock offering.
Delivery and ServiceStock heaters shipped in 24 Hours
Over 1000 Screw Plug heaters in stock
Chromalox® www.chromalox.com
Proper electrical grounding is extremely important and is required by theNational Electrical Code. Some manufacturers do not provide a standardgrounding lug with their heaters. Grounding lugs are a standard feature withChromalox heaters. Ask the heater manufacturer if a grounding lug isstandard.
Chromalox heaters undergo extensive quality inspection prior to shipment. Allscrew plug heaters are 100 percent hydrostatically pressure tested to insure atight leak-proof fit of the elements to the screw plug. We also perform a 100percent resistance check on all our heater elements to ensure proper heatingelement wattage. A two-step insulation resistance check is also performed.First, elements must have a test measurement of insulation resistance to insureminimal moisture content of the element refractory. Then, a dielectric highpotential check insures that no electrical short exists from the resistance wireto the metal sheath. Many manufacturers do not perform all of this qualityassurance testing. Ask the heater manufacturer about their testingprogram.
Chromalox has the most extensive third party listing in the industry. We providemore heaters with Underwriters Laboratory listing and/or Canadian StandardsAssociation Certification than all other heater manufacturers combined.This assures the heater is built to stringent standards and allows you to receivequick electrical inspector approval. Ask the heater manufacturer about ULListing and CSA Certification.
http://www.chromalox.com
PD315-1PDS QUALITY
OCT 9899-006
In SummaryOver 80 years of experience
Highest quality heaterconstruction
Extensive UL/CSAListings/Certifications
Comprehensive testingprior to delivery
Fast delivery andcustomer service
Chromalox has over 80 years of experience, the highest quality construction,extensive UL Listings and CSA Certifications, a comprehensive quality programand the largest stock and pre-engineered designs of any manufacturer.Chromalox also has the largest and most technically competent field salesforce in the industry. This means you get the best products and applicationsupport when you need it!To Chromalox, an educated customer is our best customer. We are proud tobuild the world’s highest quality and longest lasting screw plug heaters. Weask you to ask these questions to whomever you buy your screw plug heatersfrom. Remember, not all screw plug heaters are created equal.
Benefit
♦ Longer Lasting, More Reliable Heater
♦ Higher Consistency and Quality
♦ Longer Lasting Heaters
♦ Higher Dielectric Integrity
♦ Insulation Moisture Inhibitor
♦ Resists Chemical Attack
♦ Easier Installation, Better Fit
♦ Insures NEC Compliance for Ground
♦ Proper Enclosure Orientation Makes for Easy Installation
♦ Insures Highest Quality and Strict Manufacturing
Procedures
♦ Greater Reliability
♦ Large Stock & Assembly Stock Offering
♦ Lower Lead Times for Assembly Stock and Special Order Products
♦ Support and Assistance When You Need It Most
Feature / Benefit Analysis
Quality - Differences Among Screw Plug Immersion Heaters
Chromalox® www.chromalox.com
Feature
♦ High Quality Components
♦ Strict Manufacturing Processes
♦ Element Diameter as required
♦ Repressed Bends where necessary
♦ Standard Terminal Sealant
♦ Welded Elements
♦ Standard Hex Width and Thread Length
♦ Standard Grounding Lug
♦ Rotatable Enclosure
♦ Third Party Listing (for a list, ask your Representativefor bulletin PD314)
♦ Comprehensive Quality Assurance Testing
♦ Product Availability
♦ Responsive Production Facilitye
♦ Highly Technical and Experienced Sales Force
http://www.chromalox.com
1.000+.031-.062
REF HEX.1.500
.437 REF
.875 REF (TYP)
.248+.000-.187
"C"±.750
"B"±.125
1.000+.031-.062 .328
.187 REF (TYP)
REVISION
S
REV.D
ESCRIPTION
DA
TEBY
APVD
.
12RED
RAW
N IN
TO Pro/E FO
RMA
T, REMO
VE NO
TE 9, REVISE WA
TTAG
ETO
LERAN
CE WA
S ±5%
ECR-10993-20-06
RKCRB
13D
IMEN
SION
"C" CHA
NG
E FROM
2.125" TO 4.187". ECR 2149
11-19-08PM
OCVM
14D
IMEN
SION
"C" OF 2.125" W
AS 4.187 EXCEPT FO
R ITEMS
-075,-098,-099,-103,-107,-114,-115,-120. ECR 2219 2-26-09
PMO
FMS
15
W/
" ON
ITEM -075 W
AS 132; W
/" O
N ITEM
-098 WA
S 206;W
/" O
N ITEM
-099 WA
S 206; W/
" ON
ITEM -103 W
AS 132;
W/
" ON
ITEM -107 W
AS 204; W
/" O
N ITEM
-114 WA
S 198;W
/" O
N ITEM
-115 WA
S 198; W/
" ON
ITEM -120 W
AS 142.
DIM
. "C" ON
ITEM -099 W
AS 2.125. ECR 2337.
6-23-09RER
FMS
RY
1 Of 2
Critical to Regulatory Requirements
(x.xx=Cpk requirem
ents) Critical to Q
uality (x.xx=
Cpk requirements)
Angles: ±
2°W
attage: +5-10%
Sheet:
15156-563153-000
CU
nless otherwise specified, all
dimensions are in inches. M
etricequivalent show
n in [ ].
M
etric±
0.80±
0.25±
0.13
English±
.030±
.010±
.005
x.xx.xxx.xxx
Revision:D
rawing N
o.:Size:
IMM
ERSION
HEA
TER SCREW PLU
G (SG
)CU
STOM
ER: APPLIA
NCE PA
RTS
Third Angle Projection: U
seA
NSI Y14.5-1994 to interpret
drawing. D
o not scale drawing.
Title:G
eneral Tolerances:
Emerson H
eating Products
9-10-96S.SPRIN
GER
DW
O-054585, 156-048666-000
Date:
Approved by:
Reference:
6-16-88RM
D
ate:Checked by:
9-25-97RKC
Date:
Draw
n by:M
aterial:
PART NUMBER CATALOG NUMBER VOLTS WATTS "B" "C" FIGURE W/ " PCN NUMBER REMARKS
156-563153-
120208240277480
600600600600600
-006
-008
SG-1077
120208240277480
750750750750750
7.750 2.125 I 70
459575
459567
-011
-013
SG-1107
120208240277480
10001000100010001000
7.750 2.125 I 94
457406
459161
-016
-018
SG-1103
120208240277480
10001000100010001000
7.750 2.125 I 94
458118
458100
-021
-023
SG-1127
120208240277480
12501250125012501250
7.750 2.125 I 117
459129
457385
-027 -028
SG-1123
120208240277480
12501250125012501250
7.750 2.125 I 117
459401455363
-031
-033
SG-1157
120208240277480
15001500150015001500
7.750 2.125 I 141
459073
452613
-036 -037 -038
SG-1153
120208240277480
15001500150015001500
7.750 2.125 I 141
455347459268455355
-041
-043
SG-1207
120208240277480
20002000200020002000
10.687 2.125 I 129
455056
452621
-046 -047 -048
SG-1203
120208240277480
20002000200020002000
7.750 2.125 I 187
455400459410455339
-053
SG-2257
120208240277480
25002500250025002500
7.437 2.125 II 133
452630
-056 -057 -058
SG-1253
120208240277480
25002500250025002500
9.500 2.125 I 185
457414459428455320
-062 -063
SG-1303
120208240277480
30003000300030003000
10.687 2.125 I 194
459436452867
-066 -067
SG-1353
208240277480
3500350035003500
12.687 2.125 I 187
459444455312
-071
SG-2357
208240277480
3500350035003500
9.937 2.125 II 130
452656
NOTES: STAMP BLOCK WITH: CATALOG NUMBER, VOLTS, WATTS, DATE CODE, MANUFACTURERS LOCATION CODE AND CUSTOMER PART NUMBER WHEN SPECIFIED. 120V ELEMENTS REQUIRE "L" SUFFIX IN CATALOG DESCRIPTION, EXAMPLE: (SG-1077L) GASKET- BULK PACK (50 PCS). ALL POLY TERMINAL BLOCKS ARE TO BE BLACK WITH WHITE OR GOLD STAMP UNLESS OTHERWISE SPECIFIED. CSA MONOGRAM REQUIRED ON ELEMENTS WITH A VOLTAGE RATING OF 480V AND BELOW AND WATTAGE RATING OF 6000W AND BELOW. PLATED STEEL SCREW PLUG 1"-11 1/2 NPSM. .260 DIA. PLATED COPPER SHEATH. FOR ADDITIONAL SPECIFICATION ON REPRESS, PIN CUT, TERMINAL BLOCK HEIGHT REQUIREMENTS AND Q.A. INSPECTION REQUIREMENTS SEE DRAWING 156-895669-000 FOR HAIR PIN DESIGN (FIG 1) OR 156-895670-000 FOR FOLDBACK DESIGN (FIG II).
FIG I FIG II
#10 PHILLIPS PAN HEADTERMINAL SCREW
+.000-.187
1
2
3
4
5
6
7
8
3
7
6
1 2 4 5
REF HEX.1.500
"B"±.312
.437 REF
1.000+.031-.062
.328
"C"±.750
"B"±.125
.248+.000-.187
.875 REF (TYP)
.187 REF (TYP)
REVISION
S
REV.D
ESCRIPTION
DA
TEBY
APVD
.
12RED
RAW
N IN
TO Pro/E FO
RMA
T, REMO
VE NO
TE 9, REVISE WA
TTAG
ETO
LERAN
CE WA
S ±5%
ECR-10993-21-06
RKCRB
13D
IMEN
SION
"C" CHA
NG
E FROM
2.125" TO 4.187". ECR 2149
11-19-08PM
OCVM
14D
IMEN
SION
"C" OF 2.125" W
AS 4.187 EXCEPT FO
R ITEMS
-075,-098,-099,-103,-107,-114,-115,-120. ECR 2219 2-26-09
PMO
FMS
15
W/
" ON
ITEM -075 W
AS 132; W
/" O
N ITEM
-098 WA
S 206;W
/" O
N ITEM
-099 WA
S 206; W/
" ON
ITEM -103 W
AS 132;
W/
" ON
ITEM -107 W
AS 204; W
/" O
N ITEM
-114 WA
S 198;W
/" O
N ITEM
-115 WA
S 198; W/
" ON
ITEM -120 W
AS 142.
DIM
. "C" ON
ITEM -099 W
AS 2.125. ECR 2337.
6-23-09RER
FMS
RY
2 Of 2
Critical to Regulatory Requirements
(x.xx=Cpk requirem
ents) Critical to Q
uality (x.xx=
Cpk requirements)
Angles: ±
2°W
attage: +5-10%
Sheet:
15156-563153-000
CU
nless otherwise specified, all
dimensions are in inches. M
etricequivalent show
n in [ ].
M
etric±
0.80±
0.25±
0.13
English±
.030±
.010±
.005
x.xx.xxx.xxx
Revision:D
rawing N
o.:Size:
IMM
ERSION
HEA
TER SCREW PLU
G (SG
)CU
STOM
ER: (APPLIA
NCE PA
RTS)
Third Angle Projection: U
seA
NSI Y14.5-1994 to interpret
drawing. D
o not scale drawing.
Title:G
eneral Tolerances:
Emerson H
eating Products
12.20-94L.KEEFO
VER}D
WO
-054585, 156-048666-000D
ate:A
pproved by:Reference:
12-15-94A
DA
Date:
Checked by:
1-5-92RKC
Date:
Draw
n by:M
aterial:
PART NUMBER CATALOG NUMBER VOLTS WATTS "B" "C" FIGURE W/ " PCN NUMBER REMARKS
156-563153- -075
SG-2407
208240277480
4000400040004000
11.750
2.1254.1872.1252.125
II
132135132132
452664
-078 -079
SG-1403
208240277480
4000400040004000
13.687 2.125 I 196
459452455380
-083
SG-2457
208240277480
4500450045004500
11.750 2.125 II 137
452672
-086 -087
SG-1453
208240277480
4500450045004500
13.687 2.125 I 221
459460452859
-091
SG-2453
208240277480
4500450045004500
7.937 2.125 II 221
459225
-095
SG-2507
208240277480
5000500050005000
13.437 2.125 II 130
452681
-098 -099
SG-2503
208240277480
5000500050005000
9.937
4.1874.1872.1252.125
II
212212206206
459284455398
-103
SG-2557
208240277480
5500550055005500
15.125
2.1254.1872.1252.125
II
132136132132
459170
-106 -107
SG-2553
208240277480
5500550055005500
9.937
2.1254.1872.1252.125
II
204233204204
457502
-111
SG-2607
208240277480
6000600060006000
15.125 2.125 II 137
452760
-114 -115
SG-2603
208240277480
6000600060006000
11.750
4.1874.1872.1252.125
II
203203198198
459250455371
-120
SG-2307
120208240277480
30003000300030003000
9.000
2.1252.1254.1872.1252.125
II
142142146142142
452648
-123
SG-1173
120208240277480
17501750175017501750
7.750 2.125 I 164
412072
-128
SG-1163L
120208240277480
16501650165016501650
7.750 2.125 I 156
459237
-135
SG-1383
120208240277480
38003800380038003800
13.687 2.125 I 187
459230
NOTES: STAMP BLOCK WITH: CATALOG NUMBER, VOLTS, WATTS, DATE CODE, MANUFACTURERS LOCATION CODE AND CUSTOMER PART NUMBER WHEN SPECIFIED. 120V ELEMENTS REQUIRE "L" SUFFIX IN CATALOG DESCRIPTION, EXAMPLE: (SG-1077L) GASKET- BULK PACK (50 PCS). ALL POLY TERMINAL BLOCKS ARE TO BE BLACK WITH WHITE OR GOLD STAMP UNLESS OTHERWISE SPECIFIED. CSA MONOGRAM REQUIRED ON ELEMENTS WITH A VOLTAGE RATING OF 480V AND BELOW AND WATTAGE RATING OF 6000W AND BELOW. PLATED STEEL SCREW PLUG 1"-11 1/2 NPSM. .260 DIA. PLATED COPPER SHEATH. FOR ADDITIONAL SPECIFICATION ON REPRESS, PIN CUT, TERMINAL BLOCK HEIGHT REQUIREMENTS AND Q.A. INSPECTION REQUIREMENTS SEE DRAWING 156-895669-000 FOR HAIR PIN DESIGN (FIG 1) OR 156-895670-000 FOR FOLDBACK DESIGN (FIG II).
+.000.-187
FIG IIFIG I
#10 PHILLIPS PAN HEADTERMINAL SCREW
1
2
3
4
5
6
7
8
3
6
7
1 2 4 5