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US2493548A
(en)
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Boiler level alarm system
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PL35076B1
(GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
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US3054928A
(en)
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Photoelectrically controlled switching device
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US2448026A
(en)
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Electrical detecting circuit and device for testing the same
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US1448352A
(en)
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Flash light |
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US989132A
(en)
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Annunciator for explosive-engines.
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US3967192A
(en)
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Indicator lamp test circuit utilizing bidirectional thyristor switching
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US2617910A
(en)
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Control device with luminous indicator
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US1602710A
(en)
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Illuminated musical instrument
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US2019075A
(en)
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Bell ringing circuit and switch therefor
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GB769249A
(en)
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Improvements in or relating to automatic fire alarm installations
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US994218A
(en)
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Electric signaling apparatus.
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US699582A
(en)
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Signal apparatus.
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US1961748A
(en)
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Electric cathode glow lamp
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US1287186A
(en)
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Flash-light.
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US931412A
(en)
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Gas-lamp lighting and extinguishing system.
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US1653669A
(en)
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Combination flash-light and circuit tester
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US1526580A
(en)
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Island |
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US1338896A
(en)
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Fluid-pressure circuit-closer
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US1152986A
(en)
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Electrical indicator.
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US1143969A
(en)
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Circuit-controlling element.
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GB673835A
(en)
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Indicating the condition of electrical circuits
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US689830A
(en)
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Limiter or interrupter for electric circuits.
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US442451A
(en)
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Ceiling-block |
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US1115580A
(en)
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Short-circuit detector.
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