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
panel to the right. Click on one to see specific implementation details.
HTS provides systems for heating of process pipework to temperatures of up to 600C.
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
Wattagecables 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.
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. HTS advise a spiral ratio with every
quotation. 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. All heat
tracing systems provided by HTS are supplied complete with all ancillary
equipment necessary to provide a fully sealed and safe heat tracing
installation. Raychem heat tracing components are highly developed and
superbly engineered system components which allow easy installtion without any
any special equipment. Click here to learn more.
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.
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.