Thermal servo-motor, particularly for valves
AssigneeDanfoss A/S
InventorsFinn Jacobsen, Jens J. Molbaek, Jan Zangenberg, Poul S. Dam
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Abstract
The invention relates to a thermal servomotor which includes two operating elements particularly bellows boxes, which act oppositely on a valve actuating bridge. Each operating element has a temperature-dependent filling. Each operating element is connected to a relatively small container having a volume on the order of 0.2 cm.sup.3 by a capillary passage which has the effect of partially thermally insulating each operating element from the associated container. Each container contains the medium of the filling that determines the pressure and separate heating apparatus is associated with each of the two containers.
Claims15
A thermal valve actuating servomotor, comprising, casing means, valve actuating means, first and second operating elements forming expansible chambers, each said element having fixed and moveable parts with said fixed parts being connected to said casing means and said moveable parts being connected to said valve actuating means, first and second container means attached to said casing means and first and second fluid conduit means connecting said container means respectively to said expansible chambers, a temperature dependent vapour filling in each of said casing means and said chambers, first and second heating means respectively for said container means for respectively thermally influencing said fillings, said container means forming spaces which have relatively small volumes compared to the spaces formed by said expansible chambers.
Dependencies are inferred from the claim text.