Pipe insulation testers

Conference · Fri Dec 31 23:00:00 EST 1976

OSTI ID:7215167

Jury, S. H.; McElroy, D. L.; Moore, J. P.

The steady state temperature distribution of two pipe insulation testers were modeled using the HEATING5 computer code available in the computers at Oak Ridge National Laboratory. One pipe tester, which conformed to the ASTM C335 specification, had the core heater mounted inside a pipe around which the test insulation was placed. Guard heaters were employed to reduce unwanted axial heat conduction. Computer modeling showed that adjustment of the guard heaters was critical for short testers but not for long ones. A second tester, called an ideal tester, had no guard heaters, and only a simple, resistively-heated core heater. The modeling results showed that there is a minimum L/T (length to thickness ratio) that will lead to a correct value of thermal conductivity calculated at the midplane of the tester. A peripheral heater with backup insulation can be added to the ideal tester to permit selection of the mean temperature of the test insulation. The ideal tester has the advantage over the ASTM design that no balancing of heater power is required. A mock-up of the ideal tester was constructed and tested with calcium silicate pipe insulation. The core heater was a stainless steel screen, whose low thermal conductivity reduces end losses and permits use of a short tester (approx. 90 cm). Measured values on asbestos-free calcium silicate show reasonable agreement with the data of others which contain asbestos.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 7215167
• Report Number(s): CONF-770936-1
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320303* -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Equipment & Processes
42 ENGINEERING
420200 -- Engineering-- Facilities
Equipment
& Techniques
COMPUTER CALCULATIONS
ENERGY CONSERVATION
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
PERFORMANCE TESTING
STEAM LINES
STEAM SYSTEMS
TESTING
THERMAL INSULATION