Abstract: An air conditioning control system for at least two duct sections each with an associated damper comprises at least one master controller for a first pneumatic actuator for one damper and at least one tracking controller for a second pneumatic actuator for the other damper. The master controller comprises a first flow sensor producing a first flow variable signal in response to a sensed flow in the duct section associated with the said one damper. An adjustable reference or bias signal means is provided and a temperature signal is combined therewith to provide a composite signal for comparison with the flow variable signal. A resultant signal after comparison operates the first pneuamtic actuator for the said one damper. A tracking controller comprises a second flow sensor producing a second flow variable signal in response to sensed flow in the duct section associated with the other damper.

Abstract: An improved tamper-proof window unit comprising similar first and second quadrilateral centrally open frame members adapted to be mounted about an opening respectively on opposite sides of a door. Each frame member has a narrow elongated quadrilateral front panel extending generally in a plane parallel to the door and marginally about the door opening with an outer edge portion partially overlapping the door adjacent the opening. A small countersunk front-to-rear screw hole is provided on each side of the front panel to communicate with the door opening. A narrow elongated quadrilateral and generally L-shaped integral flange extends along the front panel with each L-shaped flange comprising first and second panels. The first panel of each flange projects generally rearwardly and the second panel projects from the rear edge of the first panel outwardly with respect to the door opening.

Abstract: This invention relates to a fire and smoke damper assembly capable of being positioned in interruptive disposition relative to the flow of air through a conduit wherein the assembly includes a flexible curtain movably mounted on the frame and attached in driven relation to a curtain mounting rod rotatably mounted on the frame. The rod and curtain are driven manually by biasing means or by exteriorly mounted motor means. Curtain guide elements including a pair of screens are arranged in spaced, substantially parallel relation to one another across the face of the conduit so as to define a channel in which the curtain is movable relative to the screens into and out of engagement about the curtain periphery with the frame.

Abstract: An air handling grille with an open rectangular frame which defines two opposing grooves each bounded by a narrow flange. A series of adjustable vanes each with opposite bearing studs is preassembled with elongated resilient bearing members. Each bearing member has a series of small openings to hold the bearing studs. The bearing members are mounted on the studs during preassembly and the members are thus entered in the grooves. Each member includes a flange which is deflected inwardly during assembly and thereafter latches the bearing members in assembled position. The flanges also tend to twist the bearing members restricting bearing openings therein and frictionally retaining the studs. A second series of vanes is supported by a pair of cross members. Spring clips secure the vanes on engagement with ends of the cross members.

Abstract: A tamper-proof window unit comprising similar first and second quadrilateral centrally open frame members adapted to be mounted about an opening respectively on opposite sides of a door. Each frame member has a narrow elongated quadrilateral front panel extending generally in a plane parallel to the door and marginally about the door opening with an outer edge portion partially overlapping the door adjacent the opening. A small countersunk front to rear screw hole is provided in each side of front panel of a first frame member and the opening is spaced inwardly from the outer edge of the panel so as to communicate with the door opening. A narrow elongated quadrilateral integral flange extends along and projects rearwardly toward the door from an outer edge of each front panel. A second narrow elongated quadrilateral and generally L-shaped integral flange extends along the inner edge of each front panel with each L-shaped flange comprising first and second panels.

Abstract: A conduit with inlet and discharge ends respectively for receiving a supply of air under pressure and for delivering the air at a lower pressure has a cylindrical configuration and an eliptical butterfly type damper is disposed diagonally therein. The damper turns about an axis intermediate its diagonally opposite ends and the oncoming air stream thus impinges on the upstream face of the damper on opposite sides of the axis and creates a differential force, the said differential force tending to close the damper and constituting a first closing force. A second closing force for the damper is provided by a small bellows supplied with air through a small conduit from the downstream side of an orifice member disposed in the main conduit upstream of the damper. A second and substantially larger bellows serves to open the damper and a small conduit connects the said bellows with a controller supplied with air from an upstream side of the orifice member in the main conduit.