Drains can be found on an intercooler, aftercooler, filter, dryer, receiver, drip leg, or at point of use. Drains come in many types and variants for all these applications, some quote fancy, but they fall into these basic categories. No air waste — timer operated — open tube — none yes that is a drain choice. How do your drains improve system efficiency? Besides the obvious savings of compressed air with a no-waste drain choice, there are other less obvious ways drains can save energy or cost you energy if not properly maintained.
They are key components in the quest for system efficiency and reliability. On multiple stage compressors moisture carry over from the intercooler may allow liquid into the next stage causing premature wear and possibly a catastrophic failure. Slugs of water due to drain failure can cause major problems in a desiccant dryer. Drains stuck in the open position can be a major source of wasted energy in some plants. No drain. Whether you choose to not install a drain, not repair a failed drain, or install a manual drain, the outcome is the same and falls into this category.
We see this all the time. Think about it. You purchase a filter for a reason. Done manually on every shift change you say? Very doubtful, and besides, the amount collected can change with load and season and needs to be ejected at irregular times. Either install a drain so the filter works as designed, or remove the filter, then readjust your system controls accordingly to take advantage of the lower pressure drop. Open tube. Condensate purge 1" REF. Condensate purge 31u n sty-alone REF.
Condensate purge 32u p sty-alone REF. Condensate purge 32u v REF. Shipping in 24 hours. Condensate purge ka13a10a0 REF. Shipping in 10 days. Condensate purge pwea-ac-3d REF. Condensate purge pwea-ac-6a REF. Condensate purge pwea-ac-7a REF. Shipping in 72 hours. In the drain line, the condensate and any incondensable gases must flow from the drain outlet of the plant to the steam trap.
In a properly sized drain line, the plant being drained and the body of the steam trap are virtually at the same pressure and, because of this, condensate does not flash in this line. Gravity is the driving force and is relied upon to induce flow along the pipe.
For this reason, it makes sense for the trap to be situated below the outlet of the plant being drained, and the trap discharge pipe to terminate below the trap. An exception to this is the tank heating coils discussed in Module 2.
The type of steam trap used thermostatic, thermodynamic or mechanical can affect the piping layout. Thermostatic steam traps.
Thermostatic traps will cool condensate below saturation temperature before discharging. This effectively waterlogs the drain line, often allowing condensate to back-up and flood the plant.
There are some applications where the sub-cooling of condensate has significant advantages and is encouraged. Less flash steam is produced in the trap discharge line, and the introduction of condensate into the condensate main is gentler.
Thermostatic traps discharging via open-ended pipework will waste less energy than mechanical traps because more of the sensible heat in the waterlogged condensate imparts its heat to the process; a typical example is that of a steam tracer line.
The extra length or larger diameter of drain line required to do this is usually impractical, as shown in Example Determine the minimum required length of 15 mm drain line to the thermostatic trap. From steam tables, at 3 bar g:. The required heat loss from the drain line can be calculated from Equation 2. This heat loss will be achieved from the mean condensate temperature along the drain line.
Mean condensate temperature in the drain line. The surface area of the drain line to provide the required heat loss can be calculated using Equation 2. This length of pipe 4. Two alternatives remain. One is to increase the diameter of the drain line, which is still usually impractical; the other is much simpler, to fit the correct trap for this type of application; a float-thermostatic trap which discharges condensate at steam temperature and hence requires no cooling leg.
Should a thermostatic trap be considered essential, and fitted no more than 2 metres away from the heater outlet, it would be necessary to calculate the required diameter of drain line. The heat loss required from the pipe remains the same, along with the total surface area of the pipe, but the surface area per metre length must increase. From Table 2.
The moral of this is that it is usually easier and cheaper to select the correct trap for the job, than have the wrong type of trap and fabricate a solution around it. Traps that discharge intermittently, such as thermodynamic traps, will accumulate condensate between discharges. However, they are extremely robust, will tolerate freezing ambient temperatures and have a relatively small outer surface area, meaning that heat loss to the environment is minimised.
They are not suitable for discharging condensate into flooded return lines, as will be explained later in this Block. Find a Specific Model. Technical Documents. Product Solutions. CAD 3D. Archived Documents. Webinar Recordings. Steam Theory. Engineering Calculator. TLV ToolBox. Email Magazine. Success Stories. About Us Recruitment. Contact Form Request a quote. TLV Offices Distributors.
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