Modulating gas valves and systems for modulating gas flow to gas-fired appliances are disclosed. An illustrative modulating gas valve can include at least one main valve adapted to regulate the flow of gas through a main gas conduit, at least one regulator for regulating the gas pressure outputted by...http://www.google.de/patents/US7523762?utm_source=gb-gplus-sharePatent US7523762 - Modulating gas valves and systems
