FAQ - Tubing and tubing connections

Pneumatic fittings system - tubing

Which minimum bending radius must be adhered to when using a tube in an energy chain?

Tubes made from polyurethane (type PUN-.../ PUN-H-…/ PEN-...) are especially well suited to use in energy chains. For the minimum bending radius, the following rule of thumb applies: 10 x tubing outside diameter.

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Which protective conduit MKV goes with which plug connector KSV?
Multi-plug Protective conduit
KSV-5 MKV-PG-21
KSV6-7 MKV-PG-29
KSV-8 MKV-PG-29
KSV6-12 MKV-PG-36
KSV-16-B MKV-PG-36
KSV6-22 MKV-PG-48
KSV-32-B MKV-PG-48

 

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To what pressure can the plastic pipe PQ-PA be pressurised?
Temperature range PQ-PA-12x1.5
PQ-PA-15x1.5
PQ-PA-18x2
PQ-PA-22x2
PQ-PA-28x2.5
-25° C to 23° C 15 bar 10 bar
-25° C to 30° C 14 bar 9 bar
-25° C to 40° C 12 bar 9 bar
-25° C to 50° C 10 bar 8 bar
-25° C to 60° C 9 bar 8 bar
-25° C to 70° C 8 bar 7 bar
-25° C to 75° C 7 bar 7 bar

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Which compressed air tubing is appropriate for vacuums?

All compressed air tubing which is explicitly marked as such in the catalogue.

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Does Festo manufacture hoses made of PTFE?

The Festo range includes a temperature and chemical-resistant hose made of perfluoroalkoxy (type designation PFAN). This hose is resistant to many acids and lyes, and can be used in a temperature range of -20°C to +150°C.

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What is the temperature limit for using hoses?
The permitted temperature for tubing depends on the pressure. In general, the following applies: the higher the pressure, the lower the permitted temperature. The tubing PFAN-… is permitted for temperatures up to 150° C.

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Does Festo also provide a transparent tubing?
The PUN-H-...-NT (colour "natural") is clear and therefore highly transparent. Other tubing in "natural" colour (e.g. PLN-...-NT) has more of a cloudy appearance.

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Pneumatic fittings system - fittings

Can Festo fittings and tubing be used for water?

The products (fittings/tubing series) listed below can be considered resistant to the medium of water based on tests, provided the specified parameters are adhered to:

 

Fittings series:           CK, QS-F, QS *), CRQS, QS-V0

Tube series:                     PLN, PUN-H, PUN-V0, PAN-V0, PFAN

 

Adherence to the parameters (pressure and temperature) set out below is absolutely essential; at the same time, note that these parameters/usage conditions differ from the generally applicable pneumatic technical data for these components:

- Pressure range: 1 bar to 6 bar

-       Temperature range:        1°C to 50°C              

-       Medium:                        Normal tap water with no harmful additives

-       Pressure peaks must be within the specified pressure range.

 

*) G thread fittings from the QS series only with the use of OL sealing rings

 

The permitted leakage of 0.18l/h is a maximum value for push/pull fittings, which can occur under very unfavourable conditions. In contrast to use with air, a slight water leak can lead to consequential damage in case of a fault. As a result, Festo provides no guarantee of any kind, including for slight leaks. We strongly recommend that any installation undergoes a leak test before commissioning. To ensure that leaks are prevented as permanently as possible, even with fluctuating temperatures, the specified tightening torques must also be adhered to.

 

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What's the difference between a parallel thread and a tapered thread?

Fittings with parallel threads (G) are sealed off by a sealing ring between the screw fitting and the component. The connecting surfaces are usually flat machined for this purpose. Screw fittings with tapered threads (R) create a seal thanks to their slightly wedged shape, assisted by sealing tape or previously applied sealing material.

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How large is the pitch of the push-in fitting QSM with an M7 thread?

The pitch of a QSM-M7 fitting is 1mm (M7x1).

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What are the dimensions of G threads?
Thread
designation
Diameter

inches
Outside
diameter
mm
Nut
diameter
mm
Tap hole
diameter
mm
Turns per
inch
G 1/8" 1/8 9.73 8.85 8.80 28
G 1/4" 1/4 13.16 11.89 11.80 19
G 3/8" 3/8 16.66 15.39 15.25 19
G 1/2" 1/2 20.95 19.17 19.00 14
G 3/4" 3/4 26.44 24.66 24.50 14
G 1" 1 33.25 30.93 30.75 11
G 1 1/4" 1 1/4 41.91 35.59 39.25 11
G 1 1/2" 1 1/2 47.80 45.48 45.25 11
G 2" 2 59.61 57.29 57.00 11

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What is the leakage rate of a QS-... push-in fitting?
The permissible initial leakage for a QS-... push-in fitting is 0.18 l/h per sealed connection.

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With what torque can fittings be tightened?
Fitting Max. torque
Nm
QSM-M3-... 0.7
QSM-M5-... 1.5
QSM-M7-... 2.0
QS(M)-1/8-... with R-thread 7.0
QS-1/4-... with R-thread 12.0
QS-3/8-... with R-thread 22.0
QS-1/2-... with R-thread 28.0
QS(M)-1/8-... with G-thread 10.0
QS-1/4-... with G-thread 15.0
QS-3/8-... with G-thread 25.0
QS-1/2-... with G-thread 40.0
CN/CK-M5-... with seal type OK-... 2.4
CN/CK-1/8-... with seal type OK-... 5.0
CN/CK-1/4-... with seal type OK-... 12.0
CN/CK-3/8-... with seal type OK-... 15.0
CN/CK-1/2-... with seal type OK-... 18.0
CN/CK-M5-... with seal type OL-... 2.0
CN/CK-1/8-... with seal type OL-... 4.0
CN/CK-1/4-... with seal type OL-... 11.0
CN/CK-3/8-... with seal type OL-... 40.0
CN/CK-1/2-... with seal type OL-... 50.0

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What is the maximum permissible length of fitting threads?

The part of the fitting that can be screwed into a valve (for example) may not exceed a maximum length. If you use Festo fittings, the length is guaranteed to be correct.

 

 

Thread diameter C max mm
M3 3.3
M5 4.3
M7 5.8
G 1/8 6.5
G 1/4 8.0
G 3/8 9.0
G 1/2 10.5
G 3/4 12.0
G 1 13.0

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What is the temperature limit for using fittings?
Standard fittings may be used for temperatures up to +80° C. QS-F-... fittings are suitable for temperatures up to 150° C.

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Is the PTFE coating available as a spare part for QS fittings with R threads?
Festo does not offer this coating as a spare part for this fitting.

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How often can a QS-...-R... fitting be inserted and removed without damaging the seal?
QS-...fittings with conic R threads have a self-sealing PTFE coating, which enables the fitting to be re-used up to five times without additional sealing components.

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