Cheng Yao

US Patent:

55116213, Apr 30, 1996

Filed:

Apr 8, 1994

Appl. No.:

8/225317

Inventors:

Cheng Yao - Weston MA

Assignee:

Factory Mutual research - MA

International Classification:

A62C 3500

US Classification:

169 17

Abstract:

In a fire extinguishment system, aspiration type fine water spray nozzles are distributed under the ceiling of a structure to be protected. The nozzles contain venturi housings to draw combustion gases from under the ceiling and to discharge combustion gases along with steam and mist downwardly from the nozzles. The discharge from the lower end of the venturi housing is delayed by twirlers sufficiently for the water droplets sprayed within the housing to be converted to steam. The steam and combustion products provide a localized flooding effect to extinguish the fire. The water is supplied to the nozzles in a dry pipe system wherein the discharge of water in the nozzles over a fire is delayed sufficiently for at least one to two rows of nozzles (4 to 12) around the fire to be actuated. In this manner, a vortex is achieved wherein the upward thrust of the fire plume is balanced by the downward jetting action of the steam mist and combustion products to achieve an effective curtain to prevent ambient air from reaching the fire.