Dial Thermometers | Mechanical Temperature Indicators | Bimetal Helix Stem

BTG Series Bimetal Thermometers

Dial Thermometers are mechanical temperature indicators consisting of a pointer precisely connected to a bimetal helix stem.

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Dial Thermometers are mechanical temperature indicators consisting of a pointer precisely connected to a bimetal helix stem which moves due to temperature changes in the bimetal helix. It is fabricated with extreme tolerances, which results in a very sensitive temperature reading.

An anti-parallax dial is used with a concave design of the dial ring to enhance readability. Graduations for each temperature range are calculated to match deflection data of bimetallic materials. Stainless steel housing is used for corrosion resistance and the complete assembly is hermetically sealed.

Dial Design Characteristics

1. Dial Thermometers Case and Bezel

304 stainless steel standard
316 stainless steel optional
All external parts corrosion resistant to most chemicals
Parts designed for maximum strength to meet requirements of heavy duty industrial applications
Manufactured with precision tooling on modern OSHA approved stamping equipment
Statistical Process Control QA methods used to assure component quality and process consistency
Polished finish identifies Intempco quality
Cases may be silicone filled for additional dampening of extreme vibration, or to assure consistent performance in low process temperature/high environmental humidity applications

2. Lens

Extra heavy duty instrument glass standard
Shatterproof glass, tempered glass, and plastics optional

3. Pointer

Black painted aluminum
Balanced and precisely assembled to bimetal coil stem
Direct transfer of coil movement to temperature displayed on dial

4. Tagging

Available for QA tracking or for customer reference information

5. Hermetic Seal

Case/Bezel assembly is a precision interference fit
Silicone gasket provides dustproof and leakproof seal
Welded construction-Unique 360o TIG weld joins case, stem and threaded connection
Testing conforms with ASME B40.3 procedures

6. Dial Thermometers Dial

True anti-parallax dial on 3″, 4″, 5″ models
Graduations on dial ring are on the same plane as the pointer tip minimizing reading error
Concave design of dial ring enhances readability
White appearing anodized aluminum, .032″ thick
Graduations for each temperature range are calculated to match deflection data of bimetallic material
Large easy to read black numerals and graduations are printed on precision pad printing equipment

7. External Reset

Calibration adjustment using an Allen wrench discourages inadvertent tampering
Stainless steel pinion is sealed with a silicone O-ring to maintain integrity of hermetic seal
Pinion works with gear teeth cut and formed in dial
Models without reset are available

8. Threaded Connection

304 stainless steel standard
316 stainless steel optional
Precision manufactured on Intempco CNC machines

Dial Thermometers Probe Design Characteristics

Bimetal Coil

Super sensitive bimetallic helix coil
Fabricated to tight tolerances
Heat treated for stress relief
Silicone coated to minimize pointer vibration and maximize heat transfer and response time
Angular deflection of each coil is tested for perfect match with dial graduation layouts in precision calibration baths designed and built by Intempco with accuracy to ± 0,1°C

Accuracy

Per ASME B40.3 Grade A ±1% full span is guaranteed
Calibration is to standards traceable to National
Institute of Standards and Testing (NIST)
Intempco methods :
– Most careful and precise in the industry
– Produces typical accuracy better than ASME B40.3 Grade AA (1%-1/2%-1%) full span

Bimetal Bushing

Pressed into groove on stem
Centers coil in stem
302 stainless steel stem wire goes through center of bushing connecting bimetal element to pointer, minimizes coil touching tube wall
Centering bearings are used at regular intervals on long stem thermometers

Temperature Ranges

20 Standard Celsius ranges from -75° to 550°
20 Standard Fahrenheit ranges from -100° to 1000°
13 Standard Dual scale ranges : °F external scale, °C internal scale
Availability of over 120 ranges developed, may vary by dial size

Over Temperature limits

100% : For ranges up to 121°C ( 250°F )
50% : For ranges 121°C to 289°C ( 250 °F to 550°F )
For ranges 289°C to 538°C ( 550 °F to 1000°F ) : Up t0 427°C ( 800°F ) for continuous use, intermittent use over 427°C ( 800°F )

BTG 01 Bottom Connected

BTG 02 Back Connected

BTG 03 Adjustable Angle

Stem Lengths	2.5”, 4”, 6”, 9” 12”, 15” and 24” are standard ( available up to 120” )
Stem Diameter	0.250” for “U” ≤ 42”, 0.375” for “U” > 42”
Connection	1/2” NPT standard
Construction	304 stainless steel external parts. Welded construction. SS316 available Corrosion resistant to most chemicals.
Hermetic Seal	Per ASME B40.3 dusproof and leakproof
Dial	True Anti-Parallax dial, easy-to-read from any angle, minimizes reading errors. Anodized aluminum with large black numbers and graduations.
Lens	Glass standard
Bimetal Coil	Helix coil is silicone coated on ranges below 500 ºF for vibration dampening and to maximize heat transfer and response time.
Accuracy	± 1% of full span per ASME B40.3 Grade A
Calibration Feature	Standard on BTG01 Series
External Reset	Easy to calibrate by inserting Allen wrench into reset opening
Over Temperature Limits	• 100% : For ranges up to 121°C ( 250 °F ) • 50% : For ranges 121°C to 289 °C ( 250 °F to 550 °F ) • For ranges 289 °C to 538 °C ( 550 °F to 1000 °F ): up to 427 °C ( 800 °F ) for continous use, intermittent use over 427 °C ( 800 °F )

BTG Series Brochure.pdf

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