초록 ▼

A butterfly damper for installation in duct work through which air and/or gases will be flowing either under a positive or negative pressure has: an outer cylindrical surface structure made of a fixed strong material; an inner flexible cylindrical surface structure made of a resilient material; a ci

A butterfly damper for installation in duct work through which air and/or gases will be flowing either under a positive or negative pressure has: an outer cylindrical surface structure made of a fixed strong material; an inner flexible cylindrical surface structure made of a resilient material; a circumferential portion of compressible material, which is always tending to return to the non-compressed form thereof, which is initially compressed between the outer cylindrical surface structure and the inner cylindrical surface structure, whereby the inside diameter of the duct body portion, initially, is uniform throughout the length thereof, and, thereafter, when the initial compressive force becomes less effective, the compressive material expands causing radially inward movement of adjacent circumferential portions of the inner flexible cylindrical surface structure; a blade to be moved across the flow of air and/or gases into sealing contact with the radially inwardly moved circumferential portions of the inner flexible cylindrical surface structure, which have been so moved upon the expansion of the compressible material, to thereby stop the flow of air and/or gases; blade mounting components secured to the outer cylindrical surface; and controllable blade movement components movably secured to the blade mounting components. In a preferred embodiment, the blade is elliptical in shape and is mounted slightly offset on a diagonal about a full shaft positioned on a transverse axis. When the blade is closed in the offset diagonal position thereof, the air and/or gas flow is completely sealed, independent of shaft seals.

대표청구항 ▼

[ We claim:] [1.] A butterfly damper adapted for installation in duct work through which air and/or gases will be flowing comprising:a. a duct body portion of the butterfly damper having:i. an outer cylindrical surface structure made of a fixed strong material;ii. an inner flexible cylindrical surfa

[ We claim:] [1.] A butterfly damper adapted for installation in duct work through which air and/or gases will be flowing comprising:a. a duct body portion of the butterfly damper having:i. an outer cylindrical surface structure made of a fixed strong material;ii. an inner flexible cylindrical surface structure made of a resilient material having a central portion and this resilient material withstands the flow of air and/or gases that may be carrying abrasive particles and corrosive substances;iii. a circumferential portion of compressible material compressed radially between the outer cylindrical surface structure and the inner flexible cylindrical surface structure at the location of the central portion of the resilient material of the inner flexible cylindrical surface structure wherein the compressed compressible material continuously urges the inner flexible cylindrical surface structure radially inward; andiv. an inside diameter of the duct body portion determined by the inside diameter of the resilient material and this inside diameter commences and ends in a same maximum internal diameter and has a reduced internal diameter throughout the central portion where the circumferential portion of the compressible material is located;b. a blade of the butterfly damper sized for partially rotating within the inner cylindrical surface structure to be moved into alignment with the flow of air and/or gases, and also to be moved across the flow of air and/or gases into sealing contact with the minimum diameter central portion of the resilient material of the inner cylindrical surface structure to thereby stop the flow of air and/or gases;c. blade mounting components secured to the duct body portion; andd. controllable blade movement components movably secured to the duct body portion.