Abstract: System and method for continuously monitoring the wet bulb temperature in a flue gas stream, for example, at the inlet of a spray dryer. A sample of the flue gas is maintained at substantially the same moisture content and temperature as the gas in the flue. The temperature of this sample is measured with a sensor surrounded by a liquid absorbent wick which is immersed in liquid maintained at a substantially constant level.

Abstract: A system and method for controlling the enivronment toward obtaining a prespecified absolute humidity within a substantially enclosed and pressurized work area such as a textile manufacturing plant is disclosed. A plurality of condition sensing signal generating sensors are positioned within the work area. A first signal generator sensor is responsive to sensed relative humidity, a second signal generator sensor is responsive to sensed dry bulb temperature, and a third signal generator sensor is responsive to sensed barometric pressure. An air washer operatively communicates with the work area for conditioning the air enclosed within the work area. A microprocessor operatively connects the air washer and the condition sensing sensors for receiving and correlating within the microprocessor the received sensed values so as to repeatedly adjust the operation of the air washer and condition the air within the work area toward obtaining the predetermined absolute humidity.

Abstract: In an air conditioner for a motor vehicle, which, for the purpose of contling the humidity, has in the ir duct suitable devices, controlled by a microcomputer. The microcomputer receives values for outside temperature, inside temperature and inside humidity, measured by sensors. From the values for outside temperature, inside temperature and inside humidity, the microcomputer determines the threshold humidity (l.sub.thresh) as the ratio of the saturated vapor pressure (P.sub.S) inside at the pane and the saturated vapor pressure (P.sub.i) of the inside air. If this difference (.DELTA.l) between threshold humidity (l.sub.thresh) and inside humidity (l.sub.i) falls below a stipulated value (x), dehumidification devices are actuated. If the stipulated value is exceeded, humidification devices are actuated.

Abstract: System and method for continuously monitoring the wet bulb temperature in a flue gas stream, for example, at the inlet of a spray dryer. A sample of the flue gas is filtered and reheated to substantially the same temperature as the gas in the flue. The temperature of the reheated sample is measured with a sensor surrounded by a liquid absorbant wick, immersed in liquid maintained at a substantially constant level in a reservoir.

Abstract: The humidity within a controlled chamber is detected with a humidity detector, the proportional value, integrated value and differentiated value of the difference between the detected signal and a preset objective value signal are added to be an operation amount signal and an oscillator of an ultrasonic humidifier is oscillated with an amplitude adjusted in response to this operation amount signal to keep the humidity within the controlled chamber constant.

Abstract: A humidity control apparatus for controlling the humidity level of air within a given area. The apparatus includes a plurality of control valves connected in fluid flow communication to a fluid supply source for injecting water into the air within the area for controlling the humidity level within the area. A controller outputs electrical signals controlling the activation of the fluid flow control valves based on temperatures and sensor inputs within the area input to the controller along the with a multi-position switch which controls the present humidity set point within the area as well as the delay between activation of various numbers of the control valves in sequence with a predescribed time delay.

Abstract: The humidity within a controlled chamber is detected with a humidity detector and the proportional value, integrated value and differentiated value of the difference between the detected signal and a preset objective value are added to form an operation amount signal. A predetermined period is divided into a spray time during which an oscillator of an ultrasonic humidifier is operated at an amplitude obtaining a predetermined sprayed amount per unit time and a stopping time during which the oscillator cooperated with such small amplitude as to generate no spray. The predetermined period is repeated and the spraying time in each fixed period is adjusted in response to the above mentioned operation amount signal to keep the humidity within the controlled chamber constant.

Abstract: The heat transfer system is for drying agricultural products, especially tobacco, and comprises a plurality of evaporators associated with a condensor and a compressor in a closed circuit. Air is also circulated in a closed circuit, heat being provided by the condensor for drying the agricultural products, with the air subsequently being cooled and dehumidified by at least one of the evaporators. Humidity and temperature may be monitored and automatically controlled, and an external evaporator may also be provided to dissipate cold and absorb external heat.

Abstract: In a fresh air valve device having a throttle valve member (2) controlled by a humidity sensitive member (10), the control may be interrupted by means of a manual adjusting device (17) for compulsory opening and compulsory closing of the valve member.

Abstract: Water flow through air/water spray heads of an automatic in duct humidification and evaporative cooling system for buildings is modulated by a pneumatic control signal delivered to rear chambers of the system's spray heads through a pneumatic signal reversing relay connected with a pneumatic signal sending line in the pneumatic control section of the system.

Abstract: An in duct humidification and evaporative cooling system for industrial and commerical buildings is disclosed. Air and water under pressure are utilized to atomize water into minute droplets which rapidly evaporate and raise the level of relative humidity while producing evaporative cooling. A first relative humidity sensor/transmitter produces a signal proportional to the relative humidity of return air, and a second relative humidity sensor/transmitter provides a signal proportional to the relative humidity of supply air. Preset receiver-controllers external to the duct receive the two signals and send them to a low signal selector which in turn sends the lower signal to a modulating water valve and to an electrical switch which opens a valve in the pressurized air supply line. A second electrical switch operatively connected in the air supply line opens a valve in the pressurized water supply line.

Abstract: A humidifier for controlling ambient moisture includes a moisture sensor having a capacitor component and a resistor component which may vary in response to the ambient moisture, a pseudo AC square-wave generator for supplying a square-wave source voltage to the sensor which is the sum of two separate square-wave voltages, and a moisture detector section to which a sensor output voltage and a reference voltage electrically representing an objective moisture value are supplied. When the sensor output voltage reaches the stable potential after the transient phenomenon to be caused by the sensor capacitor component, the moisture detector section compares the stable voltage with the above reference voltage, thereby performing the moisture detection which faithfully corresponds to the sensor resistor component.

Abstract: A stabilizer for a ventilation duct includes a sensor, sensitive to a variable parameter such as temperature, which affects the flow of air in the duct. The sensor includes an opening in a return flow conduit communicating with a deformable chamber contained within a section of the duct. As the parameter changes, pressure at the opening changes thereby affecting the volume of the chamber and likewise the volume of the section of the duct in which the chamber is located.

Abstract: An apparatus for maintaining a relatively moist ambient gas in intimate contact with a humidity sensing element includes a control nozzle for flowing relatively dry pneumatic control gas therethrough. The nozzle is adapted to be modulated for controlling the humidity within a space. A rigid control cone is coupled to the nozzle for defining a cavity therebetween and having a fixed volume. The cone includes a pin member which is movable with respect to the cone for effecting nozzle modulation. A discharge spigot is disposed in fluid flow communication with the cavity, the spigot being arranged for exhausting the pneumatic control gas to a region remote from the humidity sensing element.

Abstract: A roof cavity venting system which draws in outside air, mixes it with inside air in the roof cavity to heat the cold outside air and dehumidify the inside air, and expels the mixture into the home living quarters. The system includes exterior and interior ventilation units, a power-driven fan unit mounted in the ceiling between the living quarters and the roof cavity, and a heating element for heating the air which is drawn through the fan unit.

Abstract: A system for regulating the ventilation of a building works automatically to reduce heating and air conditioning in unoccupied rooms by making the output of air removed from each room or service area vary as a function of the amount of humidity in the flow of air leaving such service area, the overall delivery of air introduced to replace the air removed being the greatest in the service area the loosing air from which exhibits the greatest humidity. To control the flow of air to various service areas, suitable intake and exhaust openings, having valves therein, such as flap or butterfly valves are provided.

Abstract: A sensor (24) is provided to sense the humidity at the inner surface of a window of a vehicle interior. When the sensed surface humidity is above a certain value, the possibility of the window being fogged arises and a humidifier (28) is de-energized. The humidifier (28) is normally operated to increase the interior humidity to within a desirable range. When the surface humidity is above a higher value, the air interior air control system is operated to reduce the interior humidity by turning on a defroster or the like in accordance with the outside air temperature.

Abstract: A sensor (27) is provided to sense the humidity at the inner surface of a window of a vehicle interior. When the sensed surface humidity is above a certain value, the possibility of the window being fogged arises and the proportion of outside air to recirculated air is increased to 100% to reduce the interior humidity. When the surface humidity is above a higher value, the interior air control system (5) is operated to reduce the interior humidity by increasing the amount of inlet air, the inlet air temperature, etc.

Abstract: A fluid flow control device including an inlet and a pair of outlets and a diverter valve selectively operable to place the inlet in fluid communication with either the first or second outlet in response to a humidity sensitive control mechanism. The fluid flow control device is particularly adapted for utilization with an automatic clothes dryer in which the inlet is coupled to the exhaust outlet of the dryer and the valve is actuated to open the first outlet, communicating with the outside of the house, for example, when the humidity within the exhaust air exceeds a threshold value, and to open the second outlet, which is in communication with an interior space or with a duct in a hot air circulating system, when the humidity of the dryer exhaust air is below the threshold value.

Abstract: An electronic air flow responsive switch is connected in circuit with a humidistat switch for controlling operation of a humidifier in a forced air heating system. The air flow responsive switch includes a self-heating PTC (positive temperature coefficient) thermistor which enables operation of the humidifier only when the humidistat switch is closed and there exists sufficient air flow for cooling the thermistor. The air flow responsive switch and humidistat switch are mounted in a single enclosure and include plug and cord arrangements for simplifying installation of the device.

Abstract: A proportion of outside air to recirculated air is reduced when a sensed humidity in a vehicle compartment (14) drops below a first predetermined value. If the humidity is still below the first predetermined value after a certain amount of time has elapsed, a humidifier (24) is turned on. Conversely, if the humidity rises above a second predetermined value which is higher than the first predetermined value, the humidifier (24) is turned off. If the humidity is still above the second predetermined value after a certain length of time has elapsed, the proportion of outside air to recirculated air is increased.

Abstract: A humidifying apparatus for equipment for conditioning the air of vehicle has a humidity detecting circuit and a humidifying device including a spray nozzle. The humidifying device is intermittently operated by a control device. Thus, humidity in the vehicle cabin can be controlled so as to be maintained at a desired value while keeping the humidity in the cabin uniform.

Abstract: Return air from a work area is so treated as to arrive at a prescribed temperature/humidity level responsive to a direct acting absolute humidity sensing and control apparatus. The return air is mixed with fresh air, then subjected to a water spray in an air washer. The air mixture is controlled by the absolute humidity control device to maintain a constant absolute humidity level. The amount of water sprayed is controlled by a dry bulb thermostat which in turn operates to throttle the spray as necessary to reach the prescribed temperature level in an evaporative cooling technique.

Abstract: Disclosed herein is a method and a digital electronic steam humidifier control for use with a humidifier system including an electrode boiler to provide a normally repetitive fill, boil, fill-on-drain cycle. The humidifier control includes circuitry for providing an analog signal proportional to the electrode current, and a comparator network which receives the analog signal and a reference voltage and scaled voltages provided by additional circuitry to establish predetermined levels of electrode current at which the control responds.

Abstract: A greenhouse is provided with a humidifying apparatus which is located at the top of the greenhouse and includes elements for controllably humidifying the greenhouse and to circulate air therein while displacing heat downwardly from the top section of the greenhouse. The humidifying apparatus includes a misting valve connected in series with a solenoid valve, there being further provided a control which actuates the solenoid valve selectively dependent upon the percentage of humidity in the greenhouse. A pair of fans are provided on opposite sides of the misting valve, these fans facing downwardly to propel air downwardly in the greenhouse both for the purpose of air circulation and for the purpose of cycling heat downwardly since it tends to collect in the top of the greenhouse.

Abstract: A wireless form of humidity control for residential and other uses and comprising; a carrier current type of transmitter and receiver used in combination and within a conventional electrical wiring system for a building, said transmitter including a step-down transformer and a humidity sensing device disposed in compact and close proximity and with the latter provided in the power supply line for said transformer for intermittent actuation of said transformer and consequent minimal heat generation therefrom, said transmitter and receiver having an operating frequency of at least half again that of the carrier wiring and said receiver having capacitance in the signal receptive connections thereto sufficient to provide an impedance low enough to pass a given high frequency signal and high enough to block the line potential frequency and variations incident thereto.

Abstract: Apparatus for measuring and controlling the relative humidity of exhaust air from an industrial drier in which exhaust air is passed across a dry bulb and a wet bulb thermocouple from which a voltage is derived providing a measure of the relative humidity in the air in the sample. This voltage is used to control the amount of exhaust air from the drier to atmosphere. The wet bulb thermocouple is cyclically dipped in a bowl of water under the control of a timer system of the voltage to control the amount of exhaust air discharged until the wet bulb thermocouple is equilibrated with the exhaust air sampled after dipping.

Abstract: Apparatus for producing dry compressed air comprises a compressor, a separator to remove condensates, an adsorption filter to filter and dry the air and a storage tank. A valve for controlling reverse flow of air from the storage tank through the filter to the atmosphere to regenerate the adsorption filter when the compressor stops is controlled by a moisture sensitive device so that reverse flow is permitted only if the moisture control of the compressed air is above a predetermined value. The opening of a tap to discharge collected liquid from the separator is controlled by a pneumatically operated valve system so that no electrical control is required.