Abstract: A thermostat has a housing having a flange, an actuating rod secured to the housing at a first end thereof, a guide member slidably mounted on the actuating rod, a resilient seal spool provided around a second end portion of the actuating rod and secured to the guide member, a heat sensitive cylinder housing the seal spool and secured to the guide member, wax pellets provided in the heat sensitive cylinder to enclose the seal spool. The flange has a hole so as to pass a coolant, and the thickness of the resilient seal spool being set between 25% and 5% of the diameter of the actuating rod, thereby reducing a spring constant of a return spring of the thermostat.

Abstract: An improved variable volume control assembly for conditioned air systems having an improved air flow amplifying measuring means that amplifies the difference between the total pressure and the static pressure and is sensitive at low pressures, an improved air flow collector-straightener, a critical ratio of the area of the inlet to the area of the expansion chamber, and a vortex filter strategically located within the assembly for maximum reduction of turbulence and noise.

Abstract: A double walled smoke stack is made up of stackable sections. The top part of each section has a member extending between inner and outer shells and is either downwardly prestressed towards the inner shell or is flexible. This allows the inner shell to upwardly expand.