12308-15 instrumentation

Electrical heat tracing is used to:

Prevent pipelines from freezing, maintain process fluid temperatures and flows, and/or to prevent condensation in pipelines

Heat tracing is also applied to tanks and vessels to:

Compensate for heat loss through the thermal insulation

Pipes installed below the frost line are exceptions that tend to:

Not have problems with freezing due to staying at a constants temps and not going below freezing

Broad temperature control is used to maintain:

Viscosity of process fluids in order to keep them flowing ( fuel lines, cooking oil, disposal lines)

Narrow temperature control is used to keep process fluids:

Within a narrow temperature range to maintain viscosity and to prevent degradation of fluid composition

The Dew point is the temperature at which:

Vapor in a given volume of air vegans to condense to a liquid

A self regulating cable increases its:

Heat output in response to a decrease in the ambient temperature

Self regulated cables are also referred to as:

Parallel-resistance cables

As the temperature gets colder:

The conductive core and fibers on a self regulating cable contract

As the resistance drops:

Current flow increases producing heat that warms the core of fiber alone the cable

As the temperature around the cable increases:

The current flow decreases

Self regulating cables with a core heating element are used on:

Metal and plastic pipes to maintain a temperature of 225 degrees

The resistor alloy-heating element used in power-limiting cables has a:

Positive temperature coefficient (PTC), meaning as the temperature decreases the heating element decreases

Mineral-insulated cables are widely used for:

Tracing long pipelines in applications where the temp or power output requirements exceed self-regulating cable

Heating cables components and accessories-

Power connection kits, splice connections, end seals and attachment tape

Power connection kits:

Connect heat tracing product to the source

Splice connections:

Used to connect the end of one cable to another

End seals:

Seals the end of heat trace wires

Attachment tape:

Made of fiberglass

An ambient-sensing control system uses a:

Mechanical thermostat or electronic controller to measure the ambient temperature

Ambient-sensing control systems are more:

Energy efficient than a self regulating control and are widely used in freeze protection systems

Line system thermostat typical of those used in:

Hazardous areas to directly control a single heat tracing circuit

Dead leg control uses a dead leg part of a piping system as a:

Control point for the larger system

The function of equipment ground fault circuit breakers is to:

Protect the equipment rather than the personnel, it's trips at 30ma

Temperature monitoring systems continually monitor the temperature in the pipe using:

RTDS, by using the RTDs resistance to determine pipe temps

In some systems, temperature monitoring signals are communicated to the controller by means of:

A power line carrier technology, which receives temperature inputs from special end of line heat cable transmitters

Installation guides for heat tracing systems:

Verify the heating cables is not damaged, make sure you have enough cable to complete the job, leave 2 feet for connections, and always follow manufactures instructions