Abstract: An improved plenum fan for use in air handling systems. The inlet cone is first in line in the direction of airflow. It is attached to the back plate, which is in between the fan wheel and the inlet cone. The fan wheel mates with the back plate through a non-contacting labyrinth seal. The wheel inlet and outlet are both cone-shaped so that the air channels between the fan blades are tilted towards the direction of airflow. The back plate is positioned behind inlet cone to permit a pressure sensor to be mounted on the inlet side of the back plate and to permit a fixed pressure tap to be connected on the inlet cone. Thus, a short conduit may be connected to the low side of the differential pressure gauge or sensor without passing through the fan back plate.

Abstract: An improved plenum fan for use in air handling systems. The inlet cone is first in line in the direction of airflow. It is attached to the back plate, which is in between the fan wheel and the inlet cone. The fan wheel mates with the back plate through a non-contacting labyrinth seal. The wheel inlet and outlet are both cone-shaped so that the air channels between the fan blades are tilted towards the direction of airflow. The back plate is positioned behind inlet cone to permit a pressure sensor to be mounted on the inlet side of the back plate and to permit a fixed pressure tap to be connected on the inlet cone. Thus, a short conduit may be connected to the low side of the differential pressure gauge or sensor without passing through the fan back plate.

Abstract: An improved plenum fan for use in air handling systems. The inlet cone is first in line in the direction of airflow. It is attached to the back plate, which is in between the fan wheel and the inlet cone. The fan wheel mates with the back plate through a non-contacting labyrinth seal. The wheel inlet and outlet are both cone-shaped so that the air channels between the fan blades are tilted towards the direction of airflow. The back plate is positioned behind inlet cone to permit a pressure sensor to be mounted on the inlet side of the back plate and to permit a fixed pressure tap to be connected on the inlet cone. Thus, a short conduit may be connected to the low side of the differential pressure gauge or sensor without passing through the fan back plate.

Abstract: A fan system for a variable air volume heating and/or air conditioning unit comprising a fan array with a control system to eliminate surge at low operating flows and to maximize operating range. The fan control system includes a fan pressure sensor for determining the pressure rise across the fan array and a fan airflow sensor for determining the total airflow generated by the fan array. A surge controller is programmed to constantly monitor the calculated surge pressure as the fan speed control is modulating the fan speed in response to user demands. As airflow increases or decreases in response to changes in fan speed, so will the calculated surge pressure. The surge control turn fans on and off to ensure that the operating fans are running in their optimum fan speed ranges. Thus, the fans in the fan array are prevented from reaching the surge point.

Abstract: A fan system for a variable air volume heating and/or air conditioning unit comprising a fan array with a control system to eliminate surge at low operating flows and to maximize operating range. The fan control system includes a fan pressure sensor for determining the pressure rise across the fan array and a fan airflow sensor for determining the total airflow generated by the fan array. A surge controller is programmed to constantly monitor the calculated surge pressure as the fan speed control is modulating the fan speed in response to user demands. As airflow increases or decreases in response to changes in fan speed, so will the calculated surge pressure. The surge control turn fans on and off to ensure that the operating fans are running in their optimum fan speed ranges. Thus, the fans in the fan array are prevented from reaching the surge point.

Abstract: A modular, water-to-air heat exchanger with flexible tubes is adjustable in length to conform to different size cooling coils and thus provides an inexpensive, retro-fittable run-around heat recovery for pre-existing air handling systems. The heat exchanger comprises multiple heat exchange tubes formed of flexible material in a shape that permits them to be lengthened or shortened by simply moving the headers toward or away from each other. Preferably, the tubes are formed of a flexible, non-resilient material such as copper, and are shaped in a serpentine or helical manner. In this way, the tubes can be drawn out to elongate the heat exchanger or compressed to shorten it, depending on the dimension of the cooling coil in the air handler. One convenient way to control the length of the flexible tubes is to support the headers on one or more adjustment bars, each having a threaded adjustment mechanism.

Abstract: A fan unit for use in an air delivery system. The fan unit comprises a variable speed control for controlling the speed of the fan wheel in combination with a disk-type unloader assembly for controlling the air flow in response to fan speed changes. The unloader disk assembly includes an actuator that is responsive to changes in the air pressure on the disk and is biased in the closed position. At full speed, air flow through the housing presses the disk to the fully open position. As the fan speed slows and air flow declines, the actuator pulls the disk to an intermediate position, reducing the air flow through the fan. The disk unloader with its air pressure responsive actuator is also useful in fan units without a variable speed control. The fan unit may be used individually or as part of a fan array of like units.

Abstract: A wall panel assembly with a sealed joint. The sealed joint is virtually airtight even in an enclosure having an ambient air pressure substantially greater than the air pressure outside the enclosure, such as an air handling cabinet. Each joint is comprised of two abutting looped joint edges in combination with a Y-shaped seal. The looped joint edge provides added structural rigidity to the panels, and the enlarged looped ends on the joint edges enclose and protect the seal therebetween from exposure to the elements. The seal itself not only withstands positive internal air pressure but is actually improved thereby. Abutting joint edges of adjacent wall panels create a narrow channel for receiving the longitudinal flange portion of the seal, and a broader V-shaped channel to receive the enlarged body portion of the seal. In this way, the body portion of the seal is seated in a channel so that internal pressure exerted against the seal will cause the seal to appressingly engage the channel.

Abstract: An air conditioning system which incorporates evaporator coils for extracting heat from air with a liquefiable gas refrigerant, and cooling coils containing a liquid coolant, such as an aqueous ethylene glycol solution, that has been cooled by cold outside air, includes such coils joined in heat transfer relationship to a multiplicity of common heat transfer fins. Due to the improved heat transfer because of a larger fin area transferring heat from either the refrigerant-containing coils or the coolant-containing coils when either refrigerant or coolant is passed through its coils, more coolant coils can be joined to the fins, so that more effective air conditioning is obtainable when the air conditioning system is in the economizing mode (with the compressor being turned off and the cooled liquid coolant being circulated through its cooling coils).

Abstract: A baffle array or assembly comprised of a plurality of longitudinal spacer rods and baffle plates is described. The spacer rods have a body portion and a protruded portion along their length. The protruded portion has a plurality of slots therein at spaced intervals. The baffle plates have peripheral openings therein adapted to receive the body portion of the spacer rods. The baffle plates and spacer rods are assembled into an array by positioning the baffle plates at right angles to the spacer rods, passing the spacer rods through the peripheral openings in the baffle plates and engaging the thicknesses of the baffle plates within the slots in the protruded portions of the spacer rods.