FAQs     KCES - Pipe Couplings and Clamps         


What material specifications are STRAUB couplings manufactured to?

STRAUB-GRIP-L in W2 and W5,
STRAUB-FLEX and -OPEN-FLEX in W1, W2, and W5

What if there is a difference in diameter between the two pipes I am joining?

STRAUB-FLEX couplings can be used to compensate for the differences in diameter of up to 10mm, depending on the diameter in question. In particular applications, larger differences in the diameter can be compensated by using STRAUB-STEP-FLEX couplings. As the name suggests, these incorporate a step which enables larger differences in diameter to be bridged.

Do STRAUB couplings require additional mounting points?

STRAUB-GRIP couplings do not require additional mounting points.
When using STRAUB-FLEX or STRAUB-OPEN-FLEX couplings, one fixing point per coupling has to be installed.

Does the STRAUB concept also work on hard pipe surfaces?

Yes, it does. The patented anchoring rings enable faultless anchoring to be achieved even with hard pipe material surfaces.

How far can STRAUB couplings absorb pressure surges and dampen sound, compared to a welded pipe connection?

Depending on the type of coupling used, absorption (attenuation) values are 3 to 7-times better than those achieved with welded or flanged connections, meaning less likelihood of damage and less noise in the workplace.

What are the usable clamping ranges for the different coupling sizes?

The clamping ranges of the couplings vary and are indicated on the data sheets. Please see the various Products pages. Within these ranges, trouble-free installation of the coupling is ensured. Under certain conditions, it is possible for pipes of diameters outside these clamping ranges to be connected to each other. If in doubt, please contact us at KCES for a chat about the capacities of the STRAUB pipe coupling in your application.

What is the lifespan for STRAUB sealing sleeves?

Assuming favourable conditions, Straub sealing sleeves can be expected to last for over 25 years. If re-using the pipe couplings, though, it is advisable to check and replace them as necessary.

Are temporary higher operating temperatures acceptable?

Yes, they are. But if the maximum operating temperature is exceeded repeatedly or for a longer period of time, the lifespan of the sealing sleeve will be reduced.

Do STRAUB couplings also work under vacuum conditions?

Yes, they do. Values of up to 50mbar abs. can be achieved. However, when the coupling is used under vacuum conditions, the strip insert must be used.

Can installation tolerances be combined?

No, they can not. The installation tolerances given are limits that apply to the individual application. If several instances occur simultaneously, the allowable values must be reduced. If in doubt, please contact KCES.

Can STRAUB couplings accept radial load?

No, they can not. (The couplings can accept radial load to a certain extent, but this will result in coupling misalignment.)

What is the difference between the STRAUB-METAL-GRIP and STRAUB-GRIP-L type couplings?

Both are axially restrained couplings for metal pipes. The STRAUB-METAL-GRIP type is a significantly stronger design. The STRAUB-GRIP-L is strong enough for approx. 75% of all applications.

Is the STRAUB-OPEN-FLEX leak-proof with the sleeve cut? How so?

Yes, it is. The sealing sleeve is manufactured in the same way a FLEX sealing sleeve, and is then cut. Thus, cutting surfaces are achieved that absolutely match and provide 100% leak-proof sealing performance.

Do the bolts have to be re-tightened?

No. The bolts do not require to be re-tightened. STRAUB couplings are completely maintenance free.

Do the pipe ends have to be prepared?

No, they do not have to be specially prepared. You only need to remove dirt, rust or vestiges of paint. Also debur, if necessary.

What is the lifespan for STRAUB couplings?

Straub guarantees their couplings for 5 years, but 25 years and more can be achieved. There are couplings that have been in use since 1974.

You have advised that I need a strip insert. What is this used for?

It is used to protect the sealing sleeve under vacuum conditions, to fill large gaps between pipe ends, to prevent rubber swelling, axial displacement, axis misalignment, or if external overpressure is present. As part of its customer service, KCES only provides couplings with strip inserts already installed as this is better for Australian conditions.

How does the axial movement concept of the STRAUB-FLEX/-OPEN-FLEX work?

The sealing lip flexes, thereby taking up any axial movement of the pipe. Because of the specific shape of the sealing lip the coupling can compensate for a certain amount of axial change in pipe length without friction occurring between the surface of the pipe and the rubber. As a result, such movements can be absorbed as often as required. See the progressive sealing effect animation to see this concept in operation.

Why are there differences in nominal pressure between STRAUB-FLEX and STRAUB-OPEN-FLEX couplings?

Because of the slotted casings (which cause internal weakening).

Are STRAUB couplings electrically conductive?

STRAUB-GRIP-L and STRAUB-METAL-GRIP are electrically conductive. STRAUB-FLEX and STRAUB-OPEN-FLEX couplings can be made electrically conductive by using the "Current Conductor".

For any other questions or additional information, please contact:

info@kces.com.au, or tel +61 3 9728 3973