Water hammering - condensate return - flooded riseres - thermodynamic steam traps

[Iyer S]

We have a condensate draining system, to flooded risers. Thermodynamic type steam traps are used. We are experiencing Water hammering.
Thermodynamic type traps are not suitable for such system? Which type is the most suited for discharge to flooded system. Thermostatic Balanced pressure or Pumping traps?

Appreciate your inputs and recommendations on type of steam traps.
Rgds

 

[goutam_freelance]

The condensate at outlet of steam traps is at saturated pressure. At the vertical leg the pressure will be gradually less and two phase flow will start. The slug flow when hits the bends etc. will result in hammering.
There should be a collecting tank at slightly lower level than traps and from the tank water should be pumped.

Engineers, think what we have done to the environment !

https://www.linkedin.com/in/goutam-das-59743b30/

 

[mk3223]

Depending on the condensate flow rate and operating pressure for selecting the proper condensate trap or pumping trap.

Also, it's possible that the water hammer was resulted from the small condensate collecting pipe, which shouldn't be overlooked.

 

[Iyer S]

Dear Goutam / mk3223: Noted your inputs. Can you throw some light on suitability of Thermodynamic type Traps for the current scenario? If its not suitable, recommended type of traps with or without any other system changes.
Specialists in this field, like M/s Spirax Sarco, can help?

 

[katmar]

No matter what type of trap you use, when the saturated condensate exits the trap and enters the lower pressure of the condensate piping some flash steam will be formed. This is usually not a problem unless the condensate line is undersized and velocities are high. The most likely cause of the noise is when the flash steam encounters cold water. This leads to collapsing of the steam bubbles (i.e. cavitation).

Check the lines to see if cold condensate is combining with the hot condensate at any point. The condensate lines should all be insulated to save energy and to prevent cold liquid which can cause the cavitation described above. Also, if the risers are very oversized the condensate has more time to cool down. Smaller diameter risers may reduce the problem.

Katmar Software - AioFlo Pipe Hydraulics

http://katmarsoftware.com

"An undefined problem has an infinite number of solutions"

 

[TBP]

At the end of the day, all a steam trap is, is an automatic valve. It opens when it senses water or air, and closes when it sees steam. That's it. Probably half a dozen different designs, some more suited to certain applications that others. Any given manufacture's literature typically explains all.

Check out

http://kirsner.org/

for a number of excellent articles on the causes of water hammer in steam systems.

 

[FacEngrPE]

You obviously do not like the performance of thermodynamic traps in your application.
However Thermodynamic traps are stout compared with many other types of traps when subject to water hammer. They may be your best choice.
[ul]
[li]Traps with free floating balls will often become dented, and leak.[/li]
[li]Traps with floats on levers (F&T) sometimes have the ball floats collapse, and lock closed.[/li]
[li]Bellows traps - the bellows can fracture.[/li]
[li]Inverted bucket traps hold up rather well to water hammer.[/li][/ul]
The best rule of thumb with steam condensate is to pitch the system like a plumbing drain to a pump, and provide a generous vent at the pump, to let the flash steam out. Condensate systems always have two phase flow,
See this thread

https://www.eng-tips.com/viewthread.cfm?qid=106714