- Connecting compressed air pipework
- Quick couplings – connecting and disconnecting with one hand
- The material of quick couplings affects their service life
- Fitting a quick coupling into the compressed air network
- Compressed air leaks through the quick coupling
- Quick couplings for every application
- Quick couplings for safe work
- Prevo S1 type quick couplings for industrial use
Connecting compressed air pipeworkCouplings of various types serve to connect compressed air pipework:
Various types of fittings, reducers and threaded fittings are needed for the connection:
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Quick couplings – connecting and disconnecting with one hand
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Quick couplings, as the name itself suggests, make it possible to connect and disconnect pipework or hoses very quickly, as a rule with one hand. Quick couplings are fitted on the pipework at the places that are frequently disconnected, usually where pneumatic tools are changed or where whole branches of the pneumatic circuit need to be disconnected. |
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A quick coupling and a nipple create the connection
A quick coupling is fitted to the supply pipework and the corresponding nipple to the opposite pipe or hose:
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The nipple is inserted into the quick coupling and as soon as a click is heard, the connection is complete. The nipple meets the seat with the O-ring and the connection is thereby sealed. To disconnect, the sleeve of the quick coupling has to be pushed, releasing the nipple. |
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The material of quick couplings affects their service life
Quick couplings are usually made of brass, nickel-plated brass or steel.
Quick couplings of brass and nickel-plated brass
The most commonly used quick couplings of brass are cheap. They are suited more to trades than to use in industrial operations. Soft brass gets dented, and that has the following consequences:
- a reduction in flow,
- a relatively short service life,
- air leaks caused by wear.
On the portal www.kompresory-vzduchotechnika you will find a wide choice of quick couplings of the Lüdecke brand:
Quick couplings of stainless steel
Quick couplings of stainless steel are more expensive. They are suited to distribution lines in industrial operations. Stainless steel is resistant, and thanks to that the quick couplings have these properties:
- a long service life,
- good wear resistance,
- no air leaks occur.
On the portal www.kompresory-vzduchotechnika you will find a wide choice of quick couplings of the Lüdecke brand:
quick couplings of the ESE type of stainless steel
Compressed air leaks through the quick coupling
Quick couplings are the most frequent place of compressed air leaks. A typical leak in a quick coupling amounts to about 1 Nm³/h at a pressure of 7 bar.
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At an air price** of 0.30 Kč/Nm³ the cost of the leak amounts to: per hour 0.30 Kč |
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* source ADEME – the French organisation for environmental protection
** calculated for air from a 75kW Mark RMD compressor and an electricity price of 2.80 Kč/kWh
Fitting a quick coupling into the compressed air network
Whether you decide on a quick coupling of brass, nickel-plated brass or stainless steel, you have to choose the right type according to the connection to the pipework or the hose.
The size of the quick coupling according to the pipework diameter
Quick couplings for nipples according to European standards are available with nominal diameters from DN 2.7 to DN 19 for various air flows:
Quick couplings for every application
The truly wide choice of quick couplings makes it possible to choose the right one for every application: on www.kompresory-vzduchotechnika.cz you will find quick couplings divided into many series. Let us name at least some of them:
- The ESG series – high-flow quick couplings for flows up to 8 000 l/min,
- quick couplings for the plastics industry
- quick couplings to the British standard
- safety quick couplings ESIS
- quick couplings to the American standard
- quick couplings to various standards that apply in the Benelux countries and in Asia.
Quick couplings for safe work
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A quick coupling disconnects the compressed air circuit very easily and quickly. A sudden and violent release of air can injure the operator. The hose can slip out of the worker's hand and lash them. In addition, compressed air is wasted. So that the air stream does not shoot out of the pipework, quick couplings and, where applicable, nipples too are fitted with a shut-off valve. |
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Shutting off quick couplings
A connection without a shut-off valve
On disconnection air flows out – from the nipple and from the quick coupling.
One-sided shut-off
On disconnection the shut-off valve in the quick coupling closes the air stream. Air can, however, escape from the nipple.
Two-sided shut-off
The shut-off valve is in the quick coupling and in the nipple – the air flow is closed immediately after disconnection, so that no leak occurs and the air stays in the pipework.
Depressurising when disconnecting
For a safe disconnection of a compressed air circuit it is advisable first to depressurise the branch of the pipework being disconnected, that is, to reduce the air pressure in it.
Depressurising by means of the sleeve
Safety quick couplings ESIS (they comply with ČSN EN ISO 4414) with a shut-off valve make it possible, when disconnecting, first to reduce the pressure in the branch of the pipework being disconnected and only then to disconnect the coupling.
We proceed as follows
- Connecting the quick coupling: we push the nipple into the quick coupling.
- We disconnect the pipework in two steps:
a) We depressurise the branch of the network being disconnected by means of the sleeve.
b) We disconnect the nipple already without pressure.
Depressurising by means of a button
Quick couplings of the ESPN type (Prevo S1) with a button make it possible to depressurise the branch of the pipework being disconnected and to disconnect the circuit conveniently by means of the button.
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We proceed as follows:
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Prevo S1 type quick couplings for industrial use
| Prevo S1 type quick couplings for industrial use | |
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a flow 65 % higher than with ordinary couplings
The Prevo S1 quick couplings use a patented valve. A quick coupling with this valve was successfully designed without a seat. The design is ideal for high compressed air flows. |
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This is what the cross-section of an ordinary quick coupling looks like – the seat in the quick coupling causes turbulence:
The Prevo S1 quick couplings with the patented shape of the shut-off valve allow a smoother air flow.
A quick coupling in this version has a 65 % higher flow compared with an ordinary quick coupling. It will therefore serve excellently in the case of high compressed air consumption.
The Prevo S1 quick coupling is very safe.
No turbulence thanks to the absence of a seat and the patented valve.
- It meets the requirements of ISO 4414.
- After the button is pressed, the branch behind the coupling is depressurised.
- Only then can the quick coupling be removed.
- Extremely easy disconnection.
A 3-year warranty against air leaks
A three-year warranty against air leaks is provided on the Prevo S1 quick couplings. The year and week of manufacture are marked on the body of every coupling.
Colour differentiation and various sizes of quick couplings
Besides the DN7.4 diameter, various other sizes of the Prevo S1 quick couplings are available. For large flows of up to 3 686 l/min choose a quick coupling in the metal version. By the colour of the button you will easily tell the individual models of this coupling apart. The colour marking makes it easy to find your way among the individual types and prevents quick couplings from being mixed up. You will reach for the right quick coupling for your application at the first attempt.
