Abstract: An HVAC unit ventilator, particularly suited for schools and hotels, includes a single damper blade driven directly by a motor to control a supply air's mixture of return air and outside air. The damper blade is selectively pivotal to a full outside air position, a full return air position, and various intermediate mixed-air positions. The damper blade has flexible edge and end seals that create little if any frictional drag as the damper blade pivots to the intermediate positions, yet the seals provide a positive, tight seal when the damper stops at either the full outside air position or the full return air position. The unit ventilator includes a filter frame that not only supports an air filter but also provides the damper blade with sealing surfaces and structural support. For rigidity, the damper blade has somewhat of a box-like structure that is bi-directionally reinforced by ribs and triangular gussets.

Abstract: Lubrication of bearing surfaces in a scroll compressor is enhanced by a vent arrangement which makes use of increased centrifugal force, achieved by locating the outlet of the vent arrangement radially outside of the nominal circumference of the compressor's drive shaft, to both remove refrigerant gas from compressor locations where such gas can inhibit the flow and delivery of lubricant to such surfaces and to increase the lift of lubricant out of the compressor's lubricant sump. Oil retained in the upper surface of the compressor drive shaft is made immediately available for bearing lubrication upon compressor start-up to further enhance compressor lubrication.

Abstract: An HVAC air handling enclosure is comprised of individual panel assemblies each of which are fabricated from two panels or skins that are held together by double-sided adhesive tape. Adjacent panel assemblies are connected by a metal tongue-and-groove joint that relies on that same tape as a thermal break at the joint. After assembly, the thermal break and the tongue and groove elements of the joint are completely hidden from view. Moreover, the joint includes an internal cavity that can take up surplus sealant that may ooze out from within the tongue-and-groove joint during assembly, whereby the surplus sealant also remains hidden.

Abstract: A signal analyzer for calculating the power consumption and power factor of a three-phase power system driving a motor includes logic that determines whether the analyzer's own input terminals are wired in a proper or inverted manner. To do this, the signal analyzer observes a pattern of zero crossing slope values of the three line-to-line voltages of the three-phase power system and observes a pattern of zero crossing slope values of the current in the three power lines. The analyzer also compares the slope of a voltage signal as the signal passes through zero volts and the sign of a corresponding current signal that exists as the voltage signal crosses zero volts. Based on the observed voltage and current patterns and the voltage-to-current relationships, the analyzer can positively identify which of a plurality of inputs or signal wires are inverted.

Abstract: A fan inlet flow distributor comprises a skewed elliptical cone or equivalent body installed between an inlet opening of a centrifugal blower and an adjacent wall that faces the inlet. When all of the incoming airflow approaches the blower from the same general direction parallel to the wall and then makes a right turn to enter the blower's inlet, the unique shape of the flow distributor promotes a circumferentially uniform flow pattern as the air enters the fan's inlet. In some embodiments, the flow distributor comprises a skewed elliptical hyperboloid near its base and a skewed elliptical paraboloid near its vertex. The flow distributor is preferably attached to the wall and spaced apart from the fan's housing to ensure an unobstructed flow path between the distributor and the fan housing.

Abstract: A controller and method for operating an HVAC system including an air conditioning unit, such as a gas furnace, having three stages of heat output and responsive to signals from a single stage or two stage thermostat. The W1, W2, and W3 inputs to the controller may be configured for receipt of a single stage control signal simultaneously or paired as W1, W2 or W2, W3. The system controller is configured to determine which input connection arrangement is in existence and operates the system in mock one stage or mock two stage modes depending on the signals received from a single or two stage thermostat, respectively.

Abstract: A method of determining a fluid or material level. The method comprises the steps of: providing, at a first frequency, a current operatively capable of changing a capacitor; charging at least first and second capacitive devices to a predetermined voltage using the provided current; measuring the amount of current respectively necessary to charge the first and second capacitive devices to the predetermined voltage; determining a liquid level based on the measured signals from charging the first and second capacitive devices; and varying the first frequency.

Abstract: A shell-and-tube evaporator of a refrigerant system includes a refrigerant inlet distributor that traps a pocket of gaseous refrigerant to displace liquid refrigerant underneath the evaporator's tube bundle, thereby reducing the total charge of refrigerant in the evaporator. In some embodiments, the distributor comprises four sections interconnected by a central refrigerant feed line, which properly apportions the refrigerant to the four sections.

Abstract: An HVAC system includes a desiccant wheel, wherein the wheel's speed varies with airflow, the wheel is energized for at least a set period at startup, and/or a heat recovery system (e.g., an air-to-air heat exchanger) upstream of the wheel enhances the system's ability to dehumidify air.

Abstract: An enhanced touch-screen display system is disclosed for generating pixel coordinate estimates corresponding to a location on a display screen touched by a user. The system is an analog resistive touch-screen display system having a processor and associated software algorithms to allow for the calibration and validation of pixel coordinate estimates as an integral part of the real-time generation of the pixel coordinate estimates. Multiple calibrated pixel coordinate estimates are generated and processed at a pre-defined sampling rate to determine a valid pixel position to minimize sampling delays due to settling times. The x-axis position is also validated before the system attempts to generate a y-axis position to avoid the wasted time for generating y-axis estimates when x-axis estimates are corrupted. Noisy estimates are inherently reduced in the touch-screen display system by providing shunts across certain drivers in the system that also allow for detection of a “no touch” state.

Abstract: An air handling blower housing for an HVAC system is formed by two opposed housing parts which are each fabricated of a compression molded reinforced thermoset polymer composition. The housing parts are joined along a parting line, preferably perpendicular to the axis of a motor driven impeller mounted within the housing by wedge shaped clips which engage cooperating bosses aligned with each other when the housing parts are joined. The construction of the housing parts provides for an improved method of assembly of an air handling blower of a type particularly adapted for HVAC systems.

Abstract: A heat pump type heating and air conditioning system includes a gas furnace or other auxiliary heat source and a thermostat and controller associated with the heat pump and the auxiliary heat source for automatically energizing the heat pump if the auxiliary heat source is inoperative regardless of whether or not the automatic heating mode has been selected or the auxiliary heating mode has been selected by the user of the system. A method of operating a heat pump system with an auxiliary heating source to automatically change from operation of the heat pump to the auxiliary heating source depending on conditions such as outdoor temperature, and to automatically change back to operation of the heat pump if the auxiliary heating source is inoperable.

Abstract: A system for servicing a computer controlled machine comprising: a computer controlled machine including a device operable to perform a function, a controller controlling the operation of that device, and a data access port for transferring data and commands from the controller; and a service tool operably connected to the data access port, the service tool including a remote communications capability, a computer, and diagnostics and graphing software; and an expert observer system operably linked to the remote communications capability of the service tool and including historical machine data, machine sales information, software revisions for the controller, additional diagnostics software, and an expert observer capable of providing a mentor capability to the operator of a service tool.

Abstract: An improved two-phase refrigerant distributor for use in a falling film evaporator in a refrigeration chiller system defines apertures in its undersurface from which serrated collars depend. The serrations cooperate to define locations below the undersurface of the distributor to which liquid refrigerant is drawn prior to exiting the distributor. As a result, the hang-up and/or travel of liquid refrigerant on the distributor undersurface is reduced or eliminated.

Abstract: An air handler enclosure includes a sheet metal panel fastened to a frame of the enclosure with a gasket sealingly compressed between the frame and the face of the panel. The outer edges of the panel are folded over to create a hem that overlays the face of the panel. The gasket is placed against the face of the panel, just inside the inner periphery of the hem. When the panel is installed, the hem abuts the frame to serve as a spacer that keeps the face of the panel a certain distance away from the frame. In this way, the hem prevents the gasket from being over compressed or crushed between the frame and the face of the panel.

Abstract: An air filter assembly comprises a plastic frame containing an air permeable filter media. The media is corrugated to provide a series of pleats. Some of the pleats can be folded more compactly than others, so that the media can fit in various size frames. This can reduce the inventory of filter manufacturers and dealers. The filter frame can be plastic injection molded with integral living hinges to enable the frame to fold from a relatively flat shape to a more box-like structure. The frame includes one or more flip-up saw tooth racks that help define a main series of chambers plus a storage chamber. The main series of chambers supports a portion of the media that is more loosely folded for filtering air. The storage chamber is adjacent the main air stream and holds the more compactly folded, excess pleats.

Abstract: A filter rack is spring loaded to an expanded position to help hold the filter rack at various positions and orientations within a furnace enclosure. The rack may also include a spring-loaded channel whose position adjusts to receive filters of various widths. One set of springs urge two side members of the filter rack outward, while another set of springs urge the channel inward.

Abstract: An apparatus and method of forming serpentine heat exchanger coils from spine fin tubing involves applying spine fins to a tube while simultaneously forming the tube into a serpentine shape. The bending and fin wrapping occurs while a feed roll continues paying out the tube without interruption. Multiple bends can be made simultaneously.

Abstract: An air conditioner includes an outdoor section comprising an outdoor coil, a fan, and a refrigerant compressor housed within a cabinet. The cabinet includes an outer wrapper supported by a plastic base. The base and wrapper include features that facilitate the cabinet's assembly and shipping, enhance its appearance, and ensure its functional and structural integrity. For example, the base includes breakaway shipping tabs, lead-ins that help guide the wrapper and coil into position during assembly, and snaps that help hold the wrapper in place with a minimal number of screws. The wrapper includes watertight screw-receiving dimples for mounting electrical hardware, side panels that interconnect by way of a novel vertically sliding fit, and a spacer for protecting the coil from being crushed by the wrapper. A frame that supports the fan also supports the cabinet's top cover.