Global Combustible Gas Detectors Market By Type (by Product , Thermal Conductivity Type , Semiconductor Type , Catalytic Type , Infrared Optical Type , by Gas Type , Hydrocarbon Gas , Halogenated Hydrocarbons , Alcohols , and Other Compounds), By Application (Household , and Industrial ), By Region, and Key Companies - Industry Segment Outlook, Market Assessment, Competition Scenario, Trends and Forecast 2020-2029