All our septum assemblies are supplied with non-coring type needles manufactured from Hastelloy, they have a sharp point to pierce the septa cleanly and do not suffer from blockage problems which can cause problems with needles produced form thin wall tube.
The problem with samplers that are fitted with these kinds of needles is that the needle cuts a round plug from the rubber every time a bottle is offered up to the needles, as the sample is dispensed these are cleared but over time within the vent line these small rubber plugs can block up the sampler, causing the vent not to function like it was intended, which leads to fumes escaping around the top of the sample bottle.
The septum needles are available in several bores from 0.8mm up to 3mm. They are individually replaceable.
For small sample volumes using small bottles it is not possible to fit two needles within the assembly, in this case we supply the assembly with only one needle with the dispensing channel positioned off centre and a secondary machined slot up the side to allow the very small amount of gas to vent off. The extraction vent is then located adjacent to the bottle cap.