A heating device for a fluid storage tank is provided. The heating device comprises a heat tube including first and second elongate hollow legs which are joined together at an angle relative to each other so as to enable fluid flow therebetween. The first and second hollow legs being at least...http://www.google.de/patents/US5850503?utm_source=gb-gplus-sharePatent US5850503 - Angled heat tube for use in a fluid storage tank
