Compressed air quick release couplings: how to choose 2

[spacebeer13]

Hi,

I'm searching for a quick release coupling with minor leakages.
In most of the industries that i know there are used always the same type of quick release couplings (i don't know the type name), but i have a case that the leakeges are quite big because there are many hand tools. So i am searching for a better type of connector with less leakages.

 

[bimr]

Try Hansen or Foster. These firms supply industrial quality quick connects. It is important that the tip of the male connector does not have a sharp edge as it will quickly damage the rubber washer inside the mating female connector.

Training Manual

 

[EdStainless]

There are ones that have a secondary lock, these were designed for higher pressure but they also leak a lot less.
The other key is to require that the o-rings be replaced frequently.

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P.E. Metallurgy, Plymouth Tube

 

[spacebeer13]

Hi,

Thanks for the replies!
So, i saw several suppliers and most of them have quick connectors for compressed air suitable until 16 bar. (My application is for 7 bar).
On the other hand, i have for example Swagelock that have connectors until 200 our even 400 bar. So what you are suggesting is that maybe this last products may guarantee less leakage because they are designed for grater pressures.
For me it seems logic.

In relation to materials, what bimr pointed is seems to me also important, so i may assume that for example stainless steel connectors may be better than brass, correct?

What do you think then about Swagelock products for this case then? Do you have any feedback?

THanks

 

[moltenmetal]

Regrettably there is still no single standard for air quick connect male and female pieces. There are about four main historical ones, with the so-called "type M" manual quick connect having current market dominance. There are so-called "universal" designs which claim to accept anyone's male quick connector, and of course those can be more prone to leakage than the others over time because they try to sop up too much of the required tolerance between the metallic parts using soft goods (O-rings).

Using a 200-400 bar Swagelok stainless steel quick connect for air supply to tools is the equivalent of swatting a fly with a sledgehammer. It is also not a guarantee of an increased number of cycles to leakage. These quick connects are generally designed for and used for clean dry gases such as those supplied from compressed gas cylinders.

A normal brass quick connect intended for air, of the single shut-off design, should be more than adequate. Get connectors made for air by a reputable manufacturer (Parker etc.), and most importantly, get all the male and female parts of the same brand. Apparently, the number of ball bearings in the receiving locking mechanism also affects the leakage reliability. More balls keep the hose from pulling the connector out of axial alignment, reducing leakage. The steel male fittings tend to be more durable than the brass ones, and the use of worn or out-of-tolerance male fittings tends to lead to leakage of the female connectors which are the parts that cost money.

There are two basic styles of single shut-off quick connect intended for air: one requires the user to pull back the locking collar on the female fitting to insert the male fitting (sometimes called "manual connect"), and the other that doesn't- the male fitting can be inserted directly (sometimes called "push to connect"). The latter design is quicker and more convenient to use.

When the female quick connects start to leak, you throw them away and replace them with new ones. They cost so little that they're generally not worth repairing. If air leakage matters to you- and it should because it can cost significant money and energy- you do the periodic maintenance to replace them. If you have a 40 hour/week operation, an easy solution is to shut off your compressor during off-hours with a timed relay to reduce that air leakage when it isn't earning you any money.

 

[1gibson]

And institute a policy to disconnect tools when not in use! I can't stand walking through an empty shop after everyone goes home and hearing all the air tools hissing. Might as well just leave all the lights on too.

 

[spacebeer13]

Thanks for the replies.

moltenmetal, i agree with entirely with you i'm talking with Parker and Staubli to find a solution an i will advise the client to use good quality products and always form the same brand.
In relation to the other good practices, they already have them. the problem is that they work 24h/day and during that time we cand shut off the lines...

thanks