| 摘要 |
<p>435,083. Electrically-operated valves. BRITISH THERMOSTAT CO., Ltd., Windmill Road, Sunbury, Middlesex, and PAYNE, M., 50, Hook Road, Surbiton, Surrey. Dec. 31, 1934, No. 37370. [Class 135] In a thermostatically or pressure controlled valve a, Fig. 2, operated by a reversible electric motor through reduction gearing, the motor has two opposed field windings p, q, Fig. 3, connected respectively to two contacts g, h, of a thermostatic or pressure operated switch mechanism, the motor circuit being closed through one or other of these windings by the engagement of one or other of the contacts with a third contact j and the resulting movement of the valve opening the motor circuit so that the valve stays in its new position until a further change of temperature or pressure occurs. As shown, the windings are connected by flexible leads x, y to two insulated contacts g, h carried on leaf springs z attached to an arm f actuated by a known type of metal bellows device. These contacts embrace a third contact j adjustably mounted on a rod k connected to a screwed part n of the valve spindle b so as to move when the valve moves. The contact j is connected by a flexible lead w to a source of current. The arm f is biassed by an adjustable spring (not shown). The two contacts may be carried by the rod k and the contact j by the arm f. A rocking arm may be employed instead of the rod k. The motor is designed so as to be capable of being left indefinitely in a stalled condition without damage so that disconnection of the motor circuit in the valve end positions is avoided.</p> |
