GB307444A - Improvements in power-operated valve opening and closing apparatus - Google Patents

Abstract

307,444. Jones, C. E. Dec. 7, 1027. Electrically - actuated valves. - In poweroperated valve opening and closing apparatus, more particularly of the type described in Specification 233,760. having an alternative handactuation, means are provided whereby the hand wheel is automatically disconnected from the actuating gear before the power gear is connected and also means whereby the electric motor is free to get up speed before taking up the load. For this purpose when the electric current is switched on to the motor M it is also switched on to a solenoid S which, due to delay action of the impedance of its winding, or to a dashpot, allows the motor to speed up freely; this is followed by a. downward movement of the lever s<5> thereby withdrawing the clutch member s<12> from the hand wheel H and engaging it with the dog clutch m<9> forming part of the gearing m<6>-m<8> of the motor. At the same time the opposite end of the lever S<8> rises and allows the centrifugal governor m<10> to engage the double-disc friction clutch m<5> to rotate the gearing m<6>-m<8> and operate the valve spindle v<1>. The electric motor is stopped when the valve comes to the end of its travel bv a block D on a crosshead v<5> of the valve spindle v<1>, which operates a tappet rod B, adjustable by screws b<1>, b<2>, engaging tappets C, 0 connected with limit switches disposed within the box A.