HOPKINSONS
Valves Operated Automatically by Electric Current Control, by Solenoid, by Temperature or Other Changes in Physical Conditions; [ Pressure Gauges and ] Gauge Syphons for Steam, Water or Air; Water Gauges; [ Thermometers; Dial Thermometers; ] Electric Controlling Apparatus for Steam, Water, Gas, Air or Other Valves; [ Digital Read-Out Positional Indicators for Use in Conjunction with Machine Tools; Data Collection and Retrieval Systems Using Punch Cards, Magnetic Tapes or Other Informational M...
Registered · September 9, 1980 · 73277272 ·