Boiler Blowdown Valve Sequence Explained

Published May 14, 2019

the boiler blowdown valve sequence

Boiler Blowdown Valve Sequence

When a boiler releases steam, it leaves behind any dissolved solids and impurities. The more your organization uses a boiler, the more solids are left over in the make-up water, which leads to corrosion and scale. When you drain the water out, or ‘blow down’ the water, it keeps the process consistent, with dissolved solid concentration based on the number of cycles between blowdowns. The boiler blowdown valve sequence is what completes the process of draining.

If the boiler blowdown valve sequence is not conducted frequently enough, your boiler will fill with anything from sludge, to the hard calcium scale known as mud drum. It renders the boiler ineffective and inefficient, because all of that build up, in whatever form it takes, makes it harder for the boiler to transfer heat.

How to Complete a Boiler Blowdown

There are a few ways to complete a boiler blowdown. Water can be drained from the bottom drain valve, or a skimmer drain valve. Dissolved solids concentrate the most about six to eight inches below the water surface, making the skimmer drain valve ideal for removing solids without reducing as much boiler water. On the other hand, sludge in the boiler is at its heaviest toward the bottom, so a bottom valve blowdown is still important for reducing buildup.

Typically boiler bottom drains have a knife valve and a gate valve. The valve(s) should be piped to a discharge point that is safe. The boiler blowdown valve sequence involves ensuring both valves are closed, then opening the knife valve, then opening and closing the gate valve. Otherwise, the general advice is to open the blowdown valve closest to the boiler first, and close it last, with the actual drainage/blowing down happening from the valve furthest from the boiler. Repeating the process several times moves sludge toward the drain line.

You may also use a boiler blowdown valve sequence of opening the quick opening valve, or the one that controls the release of water, until the water in the boiler is reduced by half. Then, close all of the valves that are open and the water will blow down.

For a skimmer or surface blowdown, a needle valve is typically used, or a flow throttling valve. Boiler water goes through this valve into a skimmer pipe.

The specific method and schedule for boiler blowdown you choose depends on many factors, including the quality of the make-up water. Generally, a bottom blowdown should be completed at least once a day, and a surface blowdown can actually be automated.

Everlasting Boiler Blowdown Valves

Our Everlasting Valves are a vital part of a successful, effective boiler blowdown valve sequence. These valves incorporate our patented, rotating disc valve technology, reducing or eliminating issues with unplanned outages, constant valve replacement, and the added costs of problems like these. Our boiler blowdown valves are designed to stand up to even the toughest situations, lasting for a lifetime as they get better over time instead of wearing out like other valves. Forget about cheap valves that have to be replaced constantly to keep your boiler running.

Everlasting Valves offers manual on-off valves designed to effectively blowdown sludge, in quick opening and slow opening straight and angle configurations. Our valves are ideal for applications including steam boiler blowdown, surface blowdown, water column drain, and shut-off and stop valves. It’s all based on ASME boiler and pressure vessel section 1 codes and ANSI B16.31 power piping codes, so you can rest assured that our valves meet or exceed industry standards.

If you find your organization is frequently having to deal with boiler blowdown valves that are failing, falling apart, or just not doing the job as well as they could, it is time to switch to Everlasting Valves. Our valves are self-cleaning and offer tighter seals than most other valves on the market.

Even if you need a custom valve for your specific needs, that will not hold us back. We design and manufacture every single one of our valves so creating a custom valve is simple. Whether you choose a stock option or have a valve custom built for your company, the end result is the same — reduced maintenance costs and less downtime, which means more productivity, and higher profits.

You simply cannot go wrong with Everlasting Valves, and we are here to help you see all the benefits of working with our tough, durable, innovative products. Give us a call at 908-769-0700, email info@everlastingvalveusa.com, or contact us online. When you invest in our valves you will soon see the difference unique valves make, in the present, and in the long term.

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