Portable solar water heater - has two way non return valve with flexible plug for water to be heated

摘要

The water heater is hemispherical in shape with a hollow shell filled with water (7) to be heated. The majority of the curved area has a heat absorbant surface below which flows the heating fluid in the jacket (5). The heating fluid circulates through circuits (12,14). The container is insulated (13) below the absorbant surface underneath (5) and around the filling plug (2,4). A two-way non-return valve (15) is fitted in each heating fluid duct. The change in the sense in which the non-return valve operates is achieved by compressing the heating fluid which compresses the flexible plug in the non-return valve and causes it to sink.