For a device that serves such a simple purpose, there is a lot of confusion about what a non-return valve is, or rather what is and what isn’t a non-return valve. That’s because check valves, swing check valves and others appear in the same category. Let’s look at the options, similarities and differences.
What Does Non-Return Mean?
This is the basic answer to the whole question. A non-return valve prevents liquid or gas from flowing backwards. If it does that, it’s a non-return valve because it stops anything flowing backwards.
What Exactly is a Check Valve?
A check valve is a non-return valve. It “checks” the liquid or gas – in this case check means to stop or block. So a check valve stops liquid or gas from going back the other way. It stops it returning, so it is a non-return valve.
How About a Swing Check Valve?
A swing check valve is a non-return valve. The swing part refers to the disc being on a kind of hinge that enables it to swing forwards, allowing the liquid or gas to move where it’s supposed to be going, and if the flow pressure drops or there is some reverse pressure up ahead, the disc can swing back to the closed position, so it checks or blocks the reverse flow. That is the non-return valve’s job description, so a swing check valve is a non-return valve.
Other Types of Non-Return Valves
There are spring-loaded check valves (which obviously have a spring to help with the action of blocking or checking the flow. There are disc check foot valves and ball check valves, wafer check valves and probably valves going by other names in various places. If they stop the reverse flow, they are non-return valves. And yes, there are differences in what they are ideal for, but within one trade there will be a standard type that everybody uses, and if you are working in a particular field, you will quickly find out what everyone uses.
To make doubly sure, find yourself a good supplier with a comprehensive range of products and the knowledge to back it up. That’s us right here at Valve Warehouse Australia. You will see from the descriptions on our website which are best for which applications.
Why All The Different Names?
When someone invented the non-return valve, they didn’t make a fuss about it. They didn’t have it on the front pages of newspapers, and they didn’t get honoured by their grateful government. They just started using the idea, and as word spread and other people started making them too, you can imagine the discussions: “so how does a non-return valve work?” “It’s got his disc that swings up out of the way of the flow and falls back down to check the flow if something happens to make it try to go the other way. I call it a swing valve or a check valve.”
How To Choose The Right Non-Return Valve
In addition to the mechanism inside, you have to be aware of the size of the pipe and also the pressure of the flow, and there are so many possibilities and variations that you need to do specific research for the project you’re working on., but at least you know how a non-return valve works.