Getting the correct length of a foam pump or atomiser is really important to the final look and function of the pack. The terminology can be a bit confusing, so here are the common ways of measuring a diptube length:
- FBOG - From Base Of Gasket - from the underside of the seal to the tip of the diptube
- S2T - Seal To Tip - the same as FBOG
- LB - Length Below - measured from the tip of the diptube to the underside of the collar
- Exposed - the length of the visible part of the diptube
The total height of the bottle should be broadly the same as the Seal To Tip measurement, so for this reason Richmond uses this measurement when specifying. However, the length can change depending on other factors, so it is best to test first!
- Very thick or inflexible diptubes
- Bottles with a large push-up on the base
- Thick, viscous product which requires unrestricted orifice
- Designer/developer's choice between straight or bent diptube
- Filling line requirements where longer diptubes may hinder automation
What are the consequences of getting it wrong?
A wrongly-specified diptube could mean that the tube is too long and effectively seals against the container, meaning a viscous product cannot be drawn up the tube. An overly-long diptube can also cause trouble on filling, as excessive force is needed to push the pump onto the bottle, and could also cause stress to the pump engine, leading to the pump failing. The aesthetics of the pack could also be affected - a straight diptube may look better than a curved one. Finally, a diptube which is too short could result in the consumer unable to empty all the product from the bottle and could cause complaints.
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