Training samples were produced in a laboratory by placing the target odour inside a tank and drawing a controlled air sample through a filter via a laboratory pump.
The air was drawn downstream through the filter by means of the laboratory pump. This pump was based on the same RAS 1 K9 cargo pump covered on our Patent No; GB2455084.
The same odours were kept with each individual tank and filter holder and never change to avoid any cross-contamination during the process. This includes a blank sample.
The beauty of this system was you could have as many odours and tanks as required, but you only need one laboratory pump.
Individual companies could set up their own mini-laboratory to produce their own training samples and control accreditation samples were produced from government-approved sources.
The system was eventually superseded in the UK by DFT (Department For Transport) with a device called a TASP which screwed onto the filter holder containing a preset odour. This allowed air drawn from the cargo shed to be mixed with the preset odour inside the TASP.
The advantage of this system was the background odour was more realistic and in keeping with the working environment.
We produced our own system based on the same concept called an (ASR) or air scent regulator. But in terms of accreditation and licensing for REST approval in the UK. The TASP is the only method accepted by the DFT. However, over the system is fully adjustable lowering the smallest proportions of odour to background ratios.