Kevin Abbott, a plumber by trade, developed a piece of equipment in 2011 to fill a domestic central heating system with rust inhibitor and mains water. The prototype system worked well, so Mr Abbott looked into patenting the device. The patent agent advised that, despite its simplicity, the valve was indeed novel and, if miniaturised, could be used in medical syringes to provide dual-stage dispensing of two different liquids. Mr Abbott’s original patents, granted in Europe, the UK and the US, form the basis of new configurations for a more recent patent application.