Abstract: A fuse for safety appliances such as fire limiters in ventilation systems, the fuse comprising a first part, a second part, fusible material disposed between said first and second parts for normally maintaining said parts in fixed position with respect to one another when the fusible material is in solid form, a narrow path being defined for flow of fusible material in molten form, and the first and second parts being urged towards one another. The parts move towards one another when the fusible material melts and flows through the narrow path. The parts stop moving when the fusible material stops flowing with the parts again maintained in fixed position with respect to one another when the fusible material resolidifies.

Abstract: The control/fire damper (10) comprises a tubular shell (11) constituting a flow duct (12), a shaft (13) disposed within the flow duct (12) and carried by the shell (11), and a closing plate (14) mounted on the shaft (13), and which in the case of fire damper use continuously tends to close under the action of a spring (17). The control/fire damper (10) is provided with a clamping counterpart (15) attached to the closing plate (14) and with a clamping device (16) passing through the shell (11), which fixes the counterpart (15) steplessly in the position which is desired in each instance. The clamping device (16) consists of a clamping screw and, in fire damper use, of a member attached by fuse material to the end of the clamping screw.

Abstract: For controlling and measuring the flow of a gas in a duct, apparatus including a collar member adapted to be sealingly connected to the duct and a plurality of overlapping throttling blades pivotally carried by mounting means situated within the collar member. These blades define the side surface of a truncated cone and have upstream end regions defining the base of the cone and downstream end regions defining the of the truncated cone as well as a throttling aperture through which the gas is adapted to flow. The blades are appropriately shaped and positioned so that one side edge region of each throttling blade overlaps and resiliently engages an adjacent side edge region of an adjacent throttling blade with a positive bearing force which results in a fluidly sealed engagement between each pair of adjacent blades so that the truncated cone defined thereby is rendered gas sealed.