Connector support rings offer a valuable enhancement to the BFM® product fitting range - here's a quick guide to what they are, how and where you would use them:
Anti-collapse or support rings are stainless steel or plastic rings that can be embedded in the walls of most BFM® fitting connectors to help keep the walls open, particularly when used under negative pressure (vacuum) or when longer in length. They can also help support the connector's shape in high-pressure or compression applications, such as bag loaders, by keeping the connector open when it is compressed.
Plastic rings are often used with metal detectors because they don't interfere with their operation. Also, the plastic ring has some degree of 'flex', which allows manual compression to assist in feeding the connector and ring through the metal detector when fitting the connector in place and when removing it for cleaning.
Stainless Steel (SS) support rings can be inserted into connectors up to Ø500mm (20") in diameter, but above that size, they must be plastic support rings. Plastic support rings can be installed up to the maximum diameter of the BFM® connector range, which is Ø1,650mm (65" ).
Both types of rings are attached to the outside of the connector and fully encased inside a band of connector material, so they don't come in contact with the product itself at any stage. Rings can also be used in ATEX zones with minimal restrictions.
The longer a connector is, the greater the chance that the walls of the connector can 'collapse' or 'suck' inwards, particularly if there is vacuum or movement involved. Installing support rings along the length of longer connectors helps ensure that the connector's maximum diameter (or aperture) remains open for product flow at all times.
You can basically decide to have as many rings as you think is necessary. However, the minimum distance between rings is usually 100mm (4 inches), and the maximum number of rings that can be inserted in any standard Seeflex connector is 10.
Other materials may have slightly different manufacturing limitations when incorporating rings, so we recommend referring to our BFM® Quick Reference Limitations document for more information.
It depends on the length of the connector. Vacuum pressure tends to suck the walls of the connector inwards, and this is even more significant the longer the connector gets.
As a general guideline for vacuum applications, an unsupported BFM® connector should not exceed its diameter. For example, a 100mm (4") diameter connector operating under negative pressure should be no more than 100mm (4") in length. Where connectors are 200mm (8") or longer and used under vacuum, we recommend adding support rings.
By adding rings as the connector length increases, you can safely operate at higher negative pressures than would otherwise be possible. For instance, a 400mm (16") long connector fitted with three support rings spaced 100mm (4") apart will withstand a similar vacuum level to a 100mm (4") long connector with no rings. Tool Release (TR) connectors also offer improved vacuum resistance due to their stronger cuffs and are frequently selected for this reason.
This illustration below demonstrates how the addition of rings and Tool Release cuffs negates the effect of vacuum on connectors:
When used in positive-pressure applications, rings prevent the connector's wall from being pushed outwards and expanding (in a similar way to the inward resistance they provide against suction under vacuum).
This means you can operate a connector with rings at a higher positive pressure than you could without support rings.
Because of their secure seal and flexibility, BFM® fittings are often used in compression applications. This is typically used in applications such as bag feeders, filling heads, or bulk bag fillers, where the upper machine moves vertically, compressing the connector as it moves down.
The compression tends to fold the connector material randomly, potentially causing accelerated wear and tear. Therefore, it is recommended that connectors used in compression applications have internal support to maintain their shape.
Rings are useful when a connector must be compressed, as they help keep the connector's diameter open and prevent the connector material from folding unevenly.
An alternative to connectors with rings for this type of application is our Flexi Connector range, which has an embedded steel coil throughout the whole length of the connector..
It's a common question, and it largely depends on the application and conditions you use the connector for.
We asked our Tech Expert, Matt Bailey to provide an overview to help you decide in this quick video:
For more assistance with deciding whether you need rings in your connector, or deciding how many rings you will need, contact us today for a no-obligation chat!