{"schema_version":"1.0","canonical_url":"https://patentable.app/patents/US-8519854","patent":{"patent_number":"US-8519854","title":"Fire alarm system","assignee":null,"inventors":[],"filing_date":"2008-10-21T00:00:00.000Z","publication_date":"2013-08-27T00:00:00.000Z","cpc_codes":["G01N","G01N","G01N","G01N","G01N","G01N"],"num_claims":12,"abstract":"A fire alarm system, determining existence or nonexistence of a fire by using an ultrasound wave, comprises a sound wave generator and a sound wave detector to detect sound waves propagated through two propagation paths having different lengths each other. The system comprises a calculation means for calculating a pressure ratio between a first sound pressure, which is a sound pressure of a sound wave propagated through a first propagation path, and a second sound pressure, which is a sound pressure of a sound wave propagated through a second propagation path, and a smoke density estimator. The smoke density estimator calculates a change ratio between the pressure ratio calculated by the calculation means and a predetermined standard pressure ratio, and determines a smoke density from the change ratio based on a predetermined relational expression describing the relation between the change ratio and the smoke density, and determines existence of a fire when the smoke density exceeds a predetermined threshold."},"analysis":{"summary":null,"layman_explanation":null,"technical_analysis":null,"business_analysis":null,"faqs":null,"topics":[],"tech_cluster":null},"seo":{"title":"Fire alarm system","description":"A fire alarm system, determining existence or nonexistence of a fire by using an ultrasound wave, comprises a sound wave generator and a sound wave detector to detect sound waves propagated through tw","keywords":[]},"attribution":{"source":"Patentable","source_url":"https://patentable.app","canonical_url":"https://patentable.app/patents/US-8519854","license":"CC-BY-4.0-like","license_terms":"AI-generated analysis on this page (summary, layman_explanation, technical_analysis, business_analysis, faqs) may be reused with attribution and a visible link back to the canonical URL above. Patent abstracts, claims, and bibliographic data are USPTO public domain.","required_link":"https://patentable.app/patents/US-8519854","citation_suggestion":"Patentable. \"Fire alarm system\" (US-8519854). https://patentable.app/patents/US-8519854","copyright_holder":"Nomic Interactive Technology LLC"},"links":{"html":"https://patentable.app/patents/US-8519854","json":"https://patentable.app/api/llm-context/US-8519854","site":"https://patentable.app","llms_txt":"https://patentable.app/llms.txt"},"generated_at":"2026-05-30T22:13:54.857Z"}