One of the problems with any Closed Circuit Sampler is that when the Shell Water Detector (SWD) test is performed, it is common for the SWD capsule to fall into the jar. In order to remove it the operator has to dip his hand into the fuel, or just open the drain valve and allow the capsule to drain away with the fuel. However, this can block the drain pipework and clearing the blockage can be difficult. One solution is to fit a filter gauze inside the sampler, but this disturbs the vortex flow pattern which is so important when carrying out the visual inspection of the fuel. Also, removing the filter gauze is inconvenient and could mean that the internals will not be cleaned regularly and the internal paint surface will become scratched.
Our Capsule Catcher fits inside the drain valve so it does not interfere with the correct operation and cleaning of the sampler, and the capsule will not pass through the Capsule Catcher in the event of it falling into the fuel. The capsule can then be easily removed after draining the jar and without exposing the operator to the fuel sample. The Capsule Catcher is now fitted as standard on all new Aljac 4 litre Samplers and can also be retro fitted to samplers which are already in service.
THE AIR POWERED INTERNAL SWD
Since the introduction of the Aljac Sampler there have been various approaches to carrying out the Shell Water Detector (SWD) test, but there have been different problems associated with all of them. The best SWD test is obtained when the capsule is immersed directly into the main fuel sample because there is then no issue with dead volumes and unrepresentative fuel properties. It is also desirable to make the whole test more user friendly and reduce the consumption of syringes. So we set out with these objectives in mind when we developed our Air Powered SWD.
The Air Powered SWD consists of a graduated plastic tube which is permanently fixed to the sampler hinged lid, close coupled to a vacuum generator which creates a vacuum in the tube when air pressure is applied to the inlet connection, and this vacuum draws fuel through the SWD capsule.