Drainage recommendations for steam lines
The steam pipe system connects the steam generator and all steam-consuming equipment of the enterprise into a single system.
The main task of the steam line is the reliable transportation of steam of proper quality.
A decrease in steam quality can be caused by the presence of moisture in the steam flow in the form of fog, droplets, and sometimes partial filling of the steam line with condensate. Radiant and convective heat losses through the pipeline lead to the appearance of moisture, while the steam, losing its energy, begins to partially condense.
Accordingly, the greater the heat loss, the more condensate is formed. Therefore, it is very important to carry out high-quality insulation of all sections of the steam pipe system, which will reduce to a minimum the amount of moisture formation, accelerate the heating process of steam pipelines and the system's entry into operating mode.
To trap condensed steam in the steam line, condensate pockets are used, which are a sump- sump in the lower part of the steam line, in the form of a plugged pipe. A drain valve is installed in the lower part for manual purging at system start-up, and at the end - a condensate drain for automatic condensate drainage into the condensate line.
For effective drainage of the steam line, it is necessary to adhere to several rules below:
Condensate pocket size
The diameter of connection of drainage condensate traps is within 15-25 mm, but this will not be enough to intercept condensate in steam pipelines of larger diameter. You can use the table to determine the optimal dimensions for the components of the pocket.
The efficiency of the work is influenced not only by the correct size of the pocket, but also by its high-quality installation.
Places of installation of condensate pockets
On straight sections of steam pipelines, every 30-50m.
In the lower part of vertical pipelines (on the rise and fall).
In front of shut-off and control valves, since condensate begins to accumulate in these places after they are closed for a long time. The installation of a condensate pocket allows to minimize the erosion of their seats, while maintaining tightness and control accuracy.
Condensate not removed from the steam pipeline leads to erosion not only of shut-off and control valves, but also of the pipelines themselves.
In dead ends of steam collectors and horizontal steam lines. Here, it is also necessary to provide for the installation of thermostatic air vents for the removal of non-condensable gases such as air and carbon dioxide. Their presence provokes corrosion of pipelines and fittings, and also reduces the process of heat transfer in equipment, blocking the access of steam to the heat exchange surface.
Ensuring the slope of the steam line
The lack of a slope in the steam line or a counter-slope can lead to a decrease in drainage efficiency. This can be caused by sagging of the pipeline due to poor quality fasteners and increased spacing between fasteners.
No slope due to anchoring supports to horizontal building structures or laying along the floor.
A slope of 1: 100 can be considered sufficient.
Installation of drainage steam traps
When choosing the location of the drainage steam traps, it is necessary to establish a compromise between the convenience of their maintenance and the reduction of heat losses through the pipeline.