Temperature °Controls Pty Ltd ACN: 075 298 592 ABN: 966 501 901 83

Sydney (Head Office): 7 Yamma St, Sefton, NSW 2162 Australia Ph: 61 2 9721 8644 Fax: 61 2 9738 9339 Melbourne: 8/280 Whitehall St, Yarraville VIC 3013 Australia Ph: 61 3 9687 0000 Fax: 61 3 9687 1900 Brisbane: 28a 121 – 125 Kerry Rd, Archerfield, QLD 4108 Australi Ph: 61 7 3373 8424 Fax: 61 7 3821 3693 W: www.temperature.com.au E: sales@temperature.com.au

1661 ALL

THERMOWELL CALCULATIONS TO THE NEW

ASME PTC 19.3 TW 2016

Thermowells are used to protect Thermocouples, RTD sensors and Bimetal Thermometers

when measuring temperatures in high pressure or hostile corrosive applications in pipelines.

Thermowells are machined from solid barstock materials which are suitable for the process

medium and temperature, and supplied with a process connection, threaded, flanged or weld–

in to meet the specific installation requirements. As the flow of the medium ( Fluid or Gas )

in the pipeline passes by the thermowell it forms a turbulent wake ( known as Von Karman

trail ) that generates a vibration in the thermowell proportionate to the diameter of the

thermowell and velocity of the medium. The thermowell must be constructed sufficiently

rigid so that it’s vibration frequency does not equal the frequency of the Von Karman trail,

where the thermowell would vibrate to the point of breaking off.

The American Society of Mechanical Engineers ( ASME ) have developed a Performance

Test Code ASME PTC 19.3 TW-2016 for use to provide mathematical proof that the

material chosen and the mechanical design will not fail given the effects of the operating

conditions. The ASME PTC 19.3 TW 2016 wake frequency calculation is used for one piece

thermowells in tapered, straight or stepped stem designs from solid barstock materials,

process connections include, weld in, Flanged, Threaded and Van Stone styles, all with a

surface finish of 0.8 um Ra or better. To ensure compliance with this latest standard,

Temperature Controls have implemented a computer program to perform wake frequency

calculations on barstock thermowells to ASME PTC 19.3 TW 2016 verifying that the

specified thermowell dimensions are adequate to withstand the service conditions of

temperature, pressure, velocity and vibration. Individual Tag number calculations can be

performed as part of a quotation for supply of thermowells with the customer providing the

specific process data. A certificate of compliance is issued as part of our Quality Assurance

documentation with order shipment.

Support collars or velocity collars are used to support the stem inside the shielded length of a flange mount thermowell to theoretically reduce the insertion length. The ASME 19.2 2016-TW standard does not support the use of velocity collars as the collars do not assure a rigid support plane and so the thermowell stem will be subjected to a hammering effect brought on by the constant vibration. Positioning of thermowells It is generally believed that a temperature element must be centred in the pipe, however in practice so long as the temperature sensor is within the middle third of the pipe there is no reason to expect any decrease in measuring accuracy. Thermowells that fail to meet pressure, stress or frequency requirements as per ASME PTC 19.3 TW-2016 may be modified to reach a passable solution with modification to:- Material; an alternative material with increased mechanical properties. Insertion Length: Reducing the unsupported stem length will improve the force to natural frequency ratio. Tip Diameter: Increasing the tip diameter on a tapered stem thermowell will improve the thermowell strength, or change to a straight stem design. Fillet Radius: Increase the fillet radius to improve strength but consider the flange gasket face surface area.

THERMOWELL CALCULATIONS TO ASME PTC 19.3 TW 2016

Scope of ASME PTC 19.3 TW-2016

Tapered and Straight Design

Stepped Tip Design

Sample Certificate

Process Data Required for a calculation

Process Medium : Gas or Liquid Type

Velocity

Viscosity

Density

Maximum Temperature

Maximum Pressure

Shielded Length

Pipe Size / Schedule

Not within the scope of ASME PTC 19.3

Thermowells fabricated from pipe

Special surface finish e.g. Knurled

Thermowells with 2 or more piece welded stems

Stems that include flame spray ( stellite )or weld overlay

Ceramic or Non-metallic materials

Design Input Minimum Maximum Minimum Maximum

Unsupported Length U 63.5 mm 609.6 mm 127 mm 609.6 mm

Bore Diameter d 3.175 mm 20.9 mm 6.1 mm 6.7 mm

Tip Diameter B 9.2 mm 46.5 mm 12.7 mm

Support Diameter A 15.8 mm 80 mm

Taper Ratio B/A 0.58 1 N/A N/A

Minimum Wall Thickness 3.0 mm 3.0 mm

Temperature °Controls Pty Ltd ACN: 075 298 592 ABN: 966 501 901 83

Sydney (Head Office): 7 Yamma St, Sefton, NSW 2162 Australia Ph: 61 2 9721 8644 Fax: 61 2 9738 9339 Melbourne: 8/280 Whitehall St, Yarraville VIC 3013 Australia Ph: 61 3 9687 0000 Fax: 61 3 9687 1900 Brisbane: 28a 121 – 125 Kerry Rd, Archerfield, QLD 4108 Australia Ph: 61 7 3373 8424 Fax: 61 7 3821 3693

W: www.temperature.com.au E: sales@temperature.com.au

ASME PTC 19.3 TW‐ 2016 Process Data required for a calculation

#1661/A Before we can prepare your calculation we need you to complete the table below.

Standard Answer

Customer #

Tag #

Reference #

Material

Thermowell type

Flange size / process fitting

Flange penetration weld Partial (standard)

Full penetration (recommended)

Fillet (Root) R3 Standard (Option R5)

Bore (d) = 3.175 to 20.9mm 6.5mm

Process medium – gas or liquid

Velocity m/s

Viscosity cp

Density kg/mᶾ

Maximum design temperature

Maximum design pressure Kpa

Shielded length (Lo)

(Flanged thermowells only)

(includes standoff and pipe thickness)

Pipe size / schedule (see attached)

Overall Length (L)

Unsupported length (U) 63.5mm to 609.6mm

Lag Extensions (F)

Stem Major - Root diameter (Q) 15.8mm to 80mm

Stem Minor - Tip diameter (B) 9.2mm to 46.5mm

Taper ratio B/A 0.58

Tip thickness 6mm

Note: Calculating pipe immersion = (L) – (Lo) – (F) = pipe immersion

INSTRUMENTCONNECTION

MINORSTEM

U(UNSUPPORTED LENGTH)

STD

TIP THICKNESS (t)

BORE (d)

FILLET RADIUSSTD R3 OPTION R5

MINIMUM25mm

(L)OVERALL LENGTH REQUIRED FOR CALCULATION

B

LAGGING EXTENSION (F)

FULL PENETRATION WELD

PARTIAL PENETRATION WELD

CONDITIONS

SCALE : NTS

SIZE : A4 DATE : 13/04/12

TITLE

DRAWING BY R.B

TEMPERATURE CONTROLS PTY LTDSYDNEY : 7 YAMMA ST SEFTON , NSW 2162PHONE : (02) 9721 8644 FAX : (02) 9738 9339

THIS DRAWING IS OUREXCLUSIVE PROPERTYAND MUST NOT BECOPIED OR HANDEDTO ANY OTHER PARTIESWITH OUT WRITTENPERMISSION. IT SHALLBE RETURNED UPONREQUEST

Qual

ity S

yste

m

QualityEndorsedCompany

Certificate No:QEC 14412AS/NZS 9001:2000

MELBOURNE : 8/280 Whitehall StYARRAVILLE VIC 3013

PHONE : (03) 9687 0000 FAX : (03) 9687 1900EMAIL :sales@temperature.com.au

ASME-PTC-19.3-TW-2016

Flange Size  150# 300#  600# 900 / 1,500# 2,500#1”  16.1mm 19.1mm  23.9mm 35.4mm 41.4mm1 ½”  19.1mm  22.6mm  28.9mm  38.4mm  50.9mm 2”  21.1mm 24.1mm  31.9mm 44.9mm 57.4mmFlange (F)  57mm 57mm  80mm 80mm 90mm

MATERIAL FLANGED TAPER DESIGN BARSTOCK THERMOWELL

SPECIFY SHIELDED LENGTH (Lo)

(PIPE SIZE REQUIRED FOR CALCULATION)(INCLUDES STAND OFF AND PIPE THICKNESS)

A (Q)STEM

MAJOR

U(UNSUPPORTED LENGTH)

STD

TIP THICKNESS (t)

BORE (d)

FILLET RADIUSSTD R3 OPTION R5

MINIMUM25mm

(L)OVERALL LENGTH REQUIRED FOR CALCULATION

B

LAGGING EXTENSION (F)

FULL PENETRATION WELD

PARTIAL PENETRATION WELD

Report Information

Customer: Temperature Controls (Sample copy) Date / Time:

Tag Numbers: 0 Reference #:

Process Fluids: Gas

Pipe Size / Schedule: 6" STD

Max Temperature (T) / Pressure (P): 60 °C / 1960 KPa

Fluid Flow Rate: 34122.636 in^3/s

Fluid Velocity (v): 30 m/s

Fluid Density: 7.12 Kg/m^3

Fluid Viscosity: 0.123 centipoise

Density (Pm): 0.29 lb/in^3

Elastic Modulus, E(T): 28300000 psi

Allowable Stress (S) / Fatigue Limit (Sf): 16700 psi/9100 psi

In-Line Reson. Velocity(VIR): 42.85 m/s Von Mises Stress (Root): 76.11 psi

Bending Stress at VIR (So.max) 15253.09 psi

Dynamic Stress at V (So.max) 86.68 psi

Thermowell Configuration Frequency Limit: 0.40 Reynolds # (Re): 46941

Flanged Frequency must be below: 238.03 [Hz] Strouhal # (Ns): 0.1887

Tapered Installed Natural Freq (fnc): 595.08 [Hz] Scruton # (Nsc): 5.24

316/316L Strouhal Frequency (fs): 209.71 [Hz] Freq Ratio (fs/fnc): 0.35

2" 150#

Raised Face

316/316L Allowable Stem Pressure(Pc): 8147.09psi

6.5mm Allowable Tip Pressure(Pt): 109429.92psi

245mm

188mm

109mm Status57mm PASS31mm PASS27mm PASS6mm PASS3mm

LIC 14412

28/09/2011 10:45:07 AM

0

Process Operating Conditions

Stem Style:

Thermowell Material Properties

Stresses

Vibration

Process Connection:

Thermowell Material:

Flange Size l Rating:

PressureFlange Facing:

Flange Material:

Bore Size:

Overall Length (L):

Thermowell RatingUnsupported Length (U):

Shielded Length (Lo):

Oscillating Stress (psi) 86.68Lag Extension:

Value

284.259Tip Diameter (B):

Fillet (Root):

Frequency (Hz) 209.70Tip Thickness (t):

Steady-State Stress (psi) 369.916Root Diameter (Q):

Pressure (psi)

SAI Global

ISO 9001

The thermowell design has PASSED the wake frequency calculation“These well design calculations are based on the ASME power test code PTC 19.3- formulas. The results of these calculations

should only be used as a guide for thermowell design. Temperature Controls does not guarantee the performance of a specific

well design obtained from the use of these calculations”.

Printed using the V-MAC Wake Calc System

Nominal Pipe Size Inches

Nominal Pipe Size mm

OD mm Schedule           ANSI / ASME 

Wall thickness mm

Internal Diameter mm

1 25 33.4 STD/40/40S 3.38 26.641 25 33.4 XS/80/80S 4.55 24.30

1 1/2 40 48.3 STD/40/40S 3.68 40.941 1/2 40 48.3 XS/80/80S 5.08 38.142 50 60.3 STD/40/40S 3.91 52.482 50 60.3 XS/80/80S 5.54 49.22

2 1/2 65 73 STD/40/40S 5.16 62.682 1/2 65 73 XS/80/80S 7.01 58.983 80 88.9 STD/40/40S 5.49 77.923 80 88.9 XS/80/80S 7.62 73.66

3 1/2 90 101.6 STD/40/40S 5.74 90.123 1/2 90 101.6 XS/80/80S 8.08 85.444 100 114.3 STD/40/40S 6.02 102.264 100 114.3 XS/80/80S 8.56 97.185 125 141.3 STD/40/40S 6.55 128.205 125 141.3 XS/80/80S 9.53 122.246 150 168.3 STD/40/40S 7.11 154.086 150 168.3 XS/80/80S 10.97 146.368 200 219.1 STD/40/40S 8.18 202.748 200 219.1 XS/80/80S 12.7 193.7010 250 273.1 STD/40/40S 9.27 254.5610 250 273.1 XS/60/80S 12.70 247.7012 300 323.9 STD/40S 9.53 304.8412 300 323.9 XS/80S 12.70 298.5014 350 355.6 STD/30/40S 9.53 336.5414 350 355.6 XS/80S 12.70 330.2016 400 406.4 STD/30/40S 9.53 387.3416 400 406.4 XS/40/80S 12.70 381.0018 450 457.2 STD/40S 9.53 438.1418 450 457.2 XS/80S 12.70 431.8020 500 508 STD/20/40S 9.53 488.9420 500 508 XS/30/80S 12.70 482.6024 600 609.6 STD/20/40S 9.53 590.5424 600 609.6 XS/80S 12.70 584.2030 750 762 STD/40S 9.53 742.9430 750 762 XS/20/80S 12.70 736.6036 900 914.4 STD/40S 9.53 895.3436 900 914.4 XS/80S 12.70 889.00

PIPE SIZE / SCH FOR ASME PTC 19.3 TW 2016

For calculation purposes When calculating sheilded length use 100mm for the Stand off plus pipe thicknessLine size 50mm = 2" STD, 100mm = 4" STD, 150mm = 6" STD, 200mm = 8" STD,                           

250mm = 10" STD & 300mm = 12" STD