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Heat Tracing
Heat tracing is an application of electric surface heating. its
most common application in industrial settings is heating of pipework
and vessels though heat tracing producs in various forms have
manifold applications in commercial and industrial settings. Some
of the most common applications are listed in the below
Heat Tracing Applications
Freeze Protection
Temperature maintenance
Temperature Raise
Tank Heating
Roof & gutter de-icing
Hot water systems
. Heat tracing cables are generally constructed as cut-to-length
parallel circuit tapes or series cables. Different applications
require different types of cable but in general cable types can
be broken into two types.
Constant Wattage cables provide heating at constant output.
Constant wattage cables can be contructed as series cable elements
or cut-to-length zoned cable elements
Self Regulating
(Self-limiting) cables provide heating output which varies
inversely with temperature. Self-regulating elements are parallel
circuit cut-to-length zoned elements.
Parallel circuit, cut-to-length are the most commonly used tracing
cables. This construction allows either constant wattage or self-regulating
tracers to be cut to the desired length on site.
Constant Wattage
Heating Cables
Constant power heating cables for freeze protection or process
temperature maintenance
Series Resistance Heating
Cables
Heating tapes for use with long pipeline applications.
For use up to 230°C (446°F).
A pipework heat tracing system comprises heat tracing cable fitted
under thermal insulation. Heat tracing cables are applied normally
to the external wall of the pipework. The cables may be run straight
along the pipework or spiral wrapped around the circumference
of the pipe. The application method depends on the specific design.
There is no benefit to spiral wrapping of tracer unless the design
calls specifically for this. Heating cables are terminated to
power supplies with glanded entries similar to a standard power
cable.
A pipework heat tracing system must be designed to meet the specific
requirements of the end-user taking into account the site conditions,
the type and quantity of thermal lagging used, the exact heating
duty required and any control/feedback. Heating cables, whether
self-regulating or constant wattage are not desinged in themselves
to maintain specific temperatures. Rather the cable is applied
based on an appropriately modeled system to provide the exact
heating duty required. For this reason it is essential that any
heat tracing system be scoped and designed by trained specialists.
Professional heat tracing systems are designed for simple installation.
Control for pipework heat tracing systems is provide by means
of thermostatic switching or in some cases may be provided using
the self-regulating properties of the tracer thus necessitating
no control thermostat. In cases where the temperature will be
varied thermostatic control is always required. Control devices
fall into the following general categories.
Surface/Pipe sensing thermostats
Ambient sensing thermostats
Electronic control units
Panel mounted controllers
Multi-zone heat tracing control systems
Control systems can be self contained field mounted thermostats
providing switching of the tracer load in one self contained unit
or more sophistocated control units prividing switching of the
load and control and monitoring functionality.
Heat Tracing * System
* Cable Manufacturers
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