This varies greatly – refer to the ‘BFM® Limitations: Pressure’ and ‘BFM® Limitations: Negative Pressure’ information sheets.
A Seeflex 040E with rings will be more resilient to the vacuum than the Flexi. You could also use TR for extra resistance. Try and keep the connector as short as possible, and small gaps between rings.
Although we have tested the TR version of the BFM® Seeflex fittings under vacuum to over 0.8 bar vacuum, we would not recommend a Seeflex connector for that much pressure (refer to the ‘BFM® Limitations: Negative Pressure’ document). However, depending on the length of the connector and the type of vacuum (i.e. will it be gradual increases, is it continuous, is it sudden and/or occasional) it may be possible with the insertion of rings in the connector. The length is the most critical element as greater lengths will cause the walls to suck in further, potentially placing them in the product flow increasing likely abrasion. If having a non-transparent connector is an option, the LM4 connector is a good option. Because it is a woven fabric, the LM4 will suck in outside air which is filtered through the material.
For vacuum, the best way to keep the connector ‘open’ is to use SS Rings (This is generally only possible with connectors over 100mm long). Refer to the ‘BFM® Limitations: Negative Pressure’ document for more information. Another option is to use fabric connectors, such as the LM3 or LM4 which ‘breathe’ and filter air into the system. Refer to the ‘BFM® Limitations: Negative Pressure’ document for more information.
The BFM® fitting at longer lengths is more susceptible to pressure and vacuum. The larger diameter connectors also become less rigid in the spigot and there is a possibility that the large diameters with long lengths will cause problems by pulling out of the spigot.
Yes – our FM1 breather bag is used when you have a vessel that you are trying to fill and need to vent air. The LM4 or LM3 connector can also be used if you require your BFM® fitting (connector) to breath, often due to pressures. The LM3 breathes more air than the LM4, but could also bleed more product. This will depend on pressure, product, application and conditions.
FM1 breather bags are available in lengths from 100mm (4") to 1 metre (3ft 3").
100mm (4"): 0.10 bar 150mm (6"): 0.07 bar 200mm (8"): 0.06 bar 250mm (10"): 0.06 bar 300mm (12"): 0.02 bar
No - we cannot make a Seeflex 060ES connector with rings.
The maximum continuous operating pressure we recommend for Teflex NP is 3PSI, and short surges to 5PSI. Teflex NP is not recommended for use in negative pressure/vacuum operations.