Pipe steam tracing

[FadaSininho]

Does anyone know how to design a spiraled steam tracing for a pipe (number of spirals, spacing between spirals, tracing diameter)?
I can't find any good reference on the subject...

 

[TBP]

You cannot use a spiral configuration for steam tracing. The tracing must be arranged such that the condensate can gravity drain to a low point with a trap.

 

[Montemayor]

Fada:

TBP is exactly correct. The erroneous idea that you can/should employ horizontal, spiral-wound tubing on a pipe in order to steam-trace it is false information.

Go to:

http://www.thermon.com/catalogs/us/thermon.html

and you will obtain all the information and help you need on this subject. Note that in order to be an effective application, you should employ a cement that physically binds the straight, steam tubing to the metal pipe. This cement serves the purpose of supplying the solid medium through which the heat conduction is transferred.

 

[JimCasey]

Supplemental remark: Electric heating cable/tape is frequently spiraled on to piping, but also frequently mis-installed when it gets to a pump or valve. You can't wrap a component with a big snarl of heat tape: if the tape crosses itself you'll get hot spots and probably abbreviated service life.

 

[bimr]

From Thermon reference:

Spiraled BT or BTS tracers on horizontal runs are not recommended because circumferential expansion reduces
the heat transfer coefficient (by increasing the air gap between the tracer and the pipe) and the increased number
of pockets requires more frequent trapping.

From my corporate design guide:

For extreme heat-up requirements, bend tubing into a series of U's with a tube bender covering the entire contour of components.
Form tracer closely around body using tie-downs where necessary to keep in place.

 

[FadaSininho]

Sorry, I didn't mention that the pipe is vertical. It is a short-length pipe (2.5 ft) and the needed increase in temperature is high: the inside pipe wall temperature normally is at ambient temperature (25ºC = 77ºF) and it must be kept at 105ºC (221ºF).

We have 4.4 bar (155 ºC) steam available for the tracing and I thought in this case the spiral tracing would be more appropriate.

 

[TBP]

I shouldn't have assumed that the line was horizontal. Vertical lines - even long ones - can indeed have the steam tracing tubing arranged in a spiral. The main thing with steam is to slope everything slightly so that the condensate (and any air), can get to a low point where a trap can get it out of the system.

 

[Joesteam]

With a vertical pipe the spiral wrap of tracing is OK for condensate removal and air, however, as first mentioned, the pitch will determine the amount of heat going into the pipe. Practically, it is VERY HARD to install this way and to actually get a consistant pitch throughout the installation. For this reason it has been the industry recommendation for years to install a straight tracer and if you need more heat, install two or three parallel lines.

 

[MJCronin]

Fada.......

The above comments are correct, however they are also incomplete, you should also know that:

1) Steam tracing must always follow the bottom of piping, not spiral like electric tracing. The tracing is typically encapsulated in a "half moon" cover with a heat conducting adhesive

2) Where large valves or similar in-line components must be traced, you must loop the tube to allow drainage

3) There are length maxima. drainage slope, trap capacities and other factors that affect your steam trap "circuit" length

Finally, the people who have "written the book" on steam tracing are the kind and helpful people at Spirax Sarco...

http://www.spiraxsarco.com

They have many on-line learning resources and are very helpful.....

My opinions only

-MJC