What are the different types of Filter Drains and when they should be used?

It’s a simple process to drain contaminants from your compressed air or distribution systems, nevertheless, some applications can be used for more sophisticated draining mechanisms. This article terms several various draining mechanisms and identifies the solution each mechanism offers to specific application parameters; difficult access, such a low flow or differential pressure.

Automatic Drain:

An Automatic drain is a 2/2 valve that closes when the system is under pressure. The Drain opens when liquid collects and origins the float to rise, and on depressurization. Installation of an Auto-drain can be applied to applications where large quantities of water accumulate over a short period of time.

Semi-automatic Drain:

Semi-automatic drains function when the airline is depressurized. A semi-automatic drain is a NO 2/2 valve which is held closed by pressure acting on it. Do you know why it is semi-automatic? It’s because when the filter is pressurized, the drain is still able to operate manually by pushing the tube in the filter, which then projects outside the filter bowl.

Low-flow Drain:

The right place to use a flow-flow drain is when the compressor capacity in the application is inadequate to close a number of standard automatic drains. Low flow drains are not as effective at clearing contaminants, henceforth it should only be used when a standard automatic or semi-automatic drain can’t be used due to application.

Constant Bleed Drain:

By using a Constant Bleed drain, it means having a small hole in the bottom of the bowl, allowing condensate to constantly be removed. A Constant Bleed drain must only be used when the flow is too low to use auto-drain and when manual draining is unlikely.

 ‘Spitter’ Drain:

A Spitter drain is used when there is a different pressure amid the drain’s diaphragm and below it. The drain briefly lifts and ‘spits out’ the condensate collected under the drain. A ‘Spitter’ drain is suited to applications where there is speedy increases inflow, resultant in disparity pressure.

Drip-leg Drain:

A Drip-leg Drain is used to protect distribution systems from malfunction or damage. When systems have varying flows or shut down at the end of the day, a Drip-leg Drain should be used to eliminate water that has collected in the low points of distribution pipework. A Drip-leg Drain is attained by running a vertical pipe down starting from the low points into a Drip-leg drain where an automatic drain will eject the water.

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