National Environmental Products, Ltd.

Other

Zev Kopel

Jason Strauss

Michael Ginzburg

Caroline Duphily

Luc Briere

Harvey Weinberg

Brian J Wheeler

Shu Yong Shao

The steam humidifier fed with a premix of natural gas and forced air under low pressure (less than 1 psi) includes a main frame, a movable lower frame, a two part evaporation canister, releasably sealed, for water, an immersible combustion chamber retaining a radiant gas burner and a heat exchanger coupled downstream thereto. The heat exchanger is a coil with an upstream end coupled to the combustion chamber and a downstream end mounted through the upper part of the canister. Maintenance is enhanced by having the lower part of the evaporation tank or canister move downwardly to expose the combustion chamber and the heat exchanger coils. The coils are subject to thermal shock or relatively rapid thermal expansion and contraction which causes scale, adhered thereon, to be released and broken off. A high degree of control and modulation is achieved because the radiant burner is configured for modulated operation from a blue flame mode through a radiant mode.

Steam humidifier and method

The present invention relates to a forced-air electric heater control system for HVAC systems. One embodiment utilizes two heat sensors which are positioned upstream and downstream, equidistant from the heating element(s). The control system, in this embodiment, takes the difference between the temperature signals, thereby eliminating any radiant heat factor, and the resulting signal is used to control the heater. In other embodiments, the method senses upstream and downstream temperatures, determines air velocity in the duct, determines the amount kilowatts (KW) or other heat per unit time or power based thereon, and enables the power control switch when the resultant is less than a predetermined value. Alternate systems initially test for air velocity by application of nominal power, and then use the measured velocity and the downstream temperature to obtain a control signal for the heater. A pressure differential may be used. The systems compensate for radiant heat factor.

Forced-air heater control system and method

A hot water humidifier with an automatic siphon drain fed with cooler source water is flushed via a drain. The humidifier includes the humidifier tank and an inverted U-shaped siphon conduit having one end coupled to the tank and the other end coupled to the drain. A valve controlling the cooler source water feeds the water into the tank to maintain the temperature of an admixture of cooler source water and any preexisting tank water at or below a predetermined temperature during a flush cycle. The tank is flushed and drained via the automatic siphon based upon the level of the admixture in the tank and the level of admixture in the siphon. The source water may be coupled to the humidifier tank via the siphon conduit such that cooler source water may be added during the siphoning action. A method of flushing a hot water humidifier is also included.

Coolant fed humidifier having siphon drain and method therefor

The control system for a humidifier, which is part of a heat, ventilation or air conditioning HVAC system, detects the level of water and generates control signals by detecting the capacitance of the water in the humidifier. These control signals are used to fill the humidifier with water and control heater elements and, to some degree, drain cycles. A capacitor is utilized to detect the change in capacitance as the water level changes. The control circuit, coupled to the capacitor, generates fill control signals based upon first and second predetermined capacitive levels. In one embodiment, the capacitor sensor includes an electrically conductive element extending into the water as a first electrode which is shielded by an insulating cover, where the water acts as a medium through which capacitance is measured and the humidifier casing or another electrically conductive element in the water functions as the second electrode for the capacitor. Further refinements of the control system include a converter which converts the capacitive value of the capacitor into a frequency signal and a microprocessor which monitors that frequency signal to determine the capacitive level and hence the water level. Increasingly higher frequencies represent increasingly lower water levels. In an enhanced version, the control system further includes an electrically conductive sensor mounted in an interior top region of the humidifier for detecting the presence of foam thereat. When the capacitive sensor detects normal water levels and the conductive sensor mounted above normal water level detects foam, the microprocessor triggers corrective action. Corrective action consists of turning OFF power to the heater elements and initialing a drain cycle to clean out the critical level of impurities which created the foam. In another enhancement, the control system is configured as an adaptive feedback drain control system.

Foam, drain and fill control system for humidifier

The microprocessor based controller for the fractional horsepower actuator motor includes a capacitive power backup system. The motor is used as an actuator and is coupled to an air damper or valve. In the event of a loss of power to the controller, the controller must drive the air damper or valve to a predetermined, failsafe position. The capacitive energy source stores sufficient power to drive the motor and the coupled air damper or valve to the predetermined failsafe position. The controller includes a sensor for determining the presence or absence of power and generating a failsafe control signal. A switch receives the failsafe control signal and passes power from either the main power supply or the capacitive energy storage unit. The controller includes a microprocessor and a memory. During a failsafe operation, the microprocessor drives the motor and hence the air damper or valve to the failsafe position at full power. When the position of the air damper or valve falls within a predetermined position band near the failsafe position, the microprocessor reduces the drive signal applied to the motor in order to achieve a soft landing at the failsafe position. In another embodiment, the microprocessor will reverse the direction of the air damper or valve if the position of the damper or valve is within a further predetermined position band near the failsafe position. Thereafter, the microprocessor drives the air damper or valve via the motor to the failsafe position through the soft landing system.

Microprocessor-based controller for actuator motors with capacitive

The air velocity detector is used in combination with an air duct carrying heat, ventilation or air conditioned (HVAC) air therethrough. A rigid support subassembly is mounted in the HVAC air duct. At least a pair of ultrasonic transceivers are mounted in a spaced apart relationship facing each other on opposing end portions of the support subassembly. The acoustic, ultrasonic signal path from one transceiver to the other diagonally extends across a volume of duct covered by the rigid support subassembly. In one embodiment, the subassembly is a rigid sleeve mounted to the inboard, interior portions of the duct. In another embodiment, the subassembly is a rigid, substantially straight member diagonally extending through the duct volume. Electronic circuitry is connected to the transceivers which excites the transceivers, processes the received ultrasonic signal, and determines the phase difference or phase difference between the transmitted ultrasonic signal and the received ultrasonic signal. This phase difference representative signal is then used to calculate the velocity of the air. In one embodiment, additional temperature signals are obtained in order to determine the velocity of the air. In another embodiment, ultrasonic signals are first sent in one direction (from a first ultrasonic transceiver to a second ultrasonic transceiver) and then sent from the opposite end (from the second transceiver to the first transceiver). The resultant phase difference representative signals detected during each uni-directional transmission are subtracted from the other. The resultant signal is utilized to obtain the air velocity. In another embodiment, the system is calibrated when no air is flowing through the HVAC duct. The 'still air' time or phase difference signal is utilized as a reference signal to compute air velocity during normal HVAC operations. A method of detecting air velocity in the HVAC duct is also disclosed.

Ultrasound air velocity detector for HVAC ducts and method therefor

The emergency, fail safe capacitive energy source and circuit is used in conjunction with an air damper actuator or a valve actuator. In particular, the capacitive energy source and circuit powers a fractional horsepower motor and both the motor as well as the capacitive energy source and circuit are completely contained within an actuator container of a relatively small size. The capacitive energy source and circuit include at least one high storage capacitor (rated 0.047 farads or higher) having a volumetric size not exceeding 30 cubic inches. Preferably, a bank of high value capacitors are utilized wherein the capacitors are coupled in series or parallel to power the AC or DC motor and associated circuitry. The capacitive energy source and circuit also includes a charging circuit coupled between the motor drive power source and the capacitor or bank of capacitors. A sensor is coupled to the motor drive power source and generates a control signal in the absence of power from the motor drive power source. A switch, controlled by the control signal, is coupled to the motor drive power source and is also coupled to the capacitor or bank of capacitors. The switch has a switched output coupled to the motor. The switch passes power from the motor drive power source to the motor in the absence of the control signal from the sensor and passes power from the capacitor or bank of capacitors in the presence of the control signal. In a preferred embodiment, the sensor is a coil of DC operated relay and the switch embodied by the relay contacts and is actuated by the relay coil.

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Zev Kopel