A variable volume induction nozzle is designed for use with a variable speed fan, where fan speed is adjusted in response to variable exhaust gas flow volume in order to conserve energy. In order to maintain a minimum exhaust discharge velocity to ensure adequate plume height, an axially-extendable, upwardly tapered flow-impinging pod within the nozzle creates a variable annular nozzle outlet opening. As opposed to a circumferentially-constricted outlet opening, the variable annular outlet produces a uniform discharge velocity profile conducive to the induction of ambient air through a windband.

A combined combustion device comprises: a plurality of combustion units (2) each having a burner (4) and an air supply fan (5); an exhaust collecting pipe (10) connecting the plurality of the combustion units (2) to each other; and a check valve (7) which opens by rotation of the air supply fan (5) and prevents backflow of combustion exhaust gas from the exhaust collecting pipe (10) into each of the combustion units (2), wherein when one or more of the combustion units (2) among the plurality of the combustion units (2) are in a combustion operation state and the other one or more of the combustion units (2) are continuously maintained in a non-combustion operation state for a predetermined reference stoppage time or longer, the air supply fans (5) of the other one or more of the combustion units (2) are rotated for a certain time.

A combined combustion device comprises: a plurality of combustion units (2) each having a burner (4) and an air supply fan (5); an exhaust collecting pipe (10) connecting the plurality of the combustion units (2) to each other; and a check valve (7) which opens by rotation of the air supply fan (5) and prevents backflow of combustion exhaust gas from the exhaust collecting pipe (10) into each of the combustion units (2), wherein when one or more of the combustion units (2) among the plurality of the combustion units (2) are in a combustion operation state and the other one or more of the combustion units (2) are continuously maintained in a non-combustion operation state for a predetermined reference stoppage time or longer, the air supply fans (5) of the other one or more of the combustion units (2) are rotated for a certain time.

A set of methods and apparatus for efficiently pressurizing and ventilating an air-supported greenhouse or other structure requiring pressurization and ventilation. A method for efficiently pressurizing and ventilating an air-supported structure comprises directing any external wind flow and external wind pressure into mechanical flow means, such as a fan, or fans in parallel, operating in the intake direction, and into the internal space of the air-supported structure and out of the internal space of the air-supported structure through internal pressure regulating exhaust means, whereby the internal space of the structure will be ventilated and pressurized with the assistance of any external wind and the reliability of mechanical flow means (fans). This method allows for the efficient, effective, and economical cooling, through ventilation, of a protected space created by a light permeable membrane (cover), which is supported only by internal air pressure against the weight of the membrane and dynamic pressures of the external wind, itself. Apparatus for directing any external wind flow and external wind pressure into mechanical flow means are disclosed. Methods and apparatus for internal pressure regulation are also disclosed. Some benefits are less power consumption, minimal internal static pressure (just enough to overcome the external wind), less potential film breakage (than conventional frame-supported poly greenhouses), more light transmission, less cost, and more portability.

A water heater heats water with a combustion gas. An exhaust tube includes one end portion and the other end portion, is connected to the water heater at one end portion, and inside thereof is defined as an emission path for the combustion gas. An exhaust pipe is greater in outer diameter than the exhaust tube, and a part of the exhaust tube on a side of the other end portion is introduced in the inside thereof. An exhaust terminal is attached to an end portion of the exhaust pipe and has an exhaust port for exhausting the combustion gas to the outside. An exhaust straightening member is attached to the other end portion of the exhaust tube and has an opening portion for allowing the combustion gas to flow out toward the exhaust port.

A water heater heats water with a combustion gas. An exhaust tube includes one end portion and the other end portion, is connected to the water heater at one end portion, and inside thereof is defined as an emission path for the combustion gas. An exhaust pipe is greater in outer diameter than the exhaust tube, and a part of the exhaust tube on a side of the other end portion is introduced in the inside thereof. An exhaust terminal is attached to an end portion of the exhaust pipe and has an exhaust port for exhausting the combustion gas to the outside. An exhaust straightening member is attached to the other end portion of the exhaust tube and has an opening portion for allowing the combustion gas to flow out toward the exhaust port.

A vent that includes: a rotary head with blades arranged between a top and bottom section of the rotary head; a fixed component to mount the rotary head to a roof of a building, the fixed component having a throat that provides a flow path from inside the building to an interior of the rotary head; and a diffuser to split airflow vented from the throat and direct the vented airflow out through the rotary head.

The invention provides a device for removing heat from a building, the device having: a first tubular member defining a first cavity; a second tubular member defining a second cavity, whereby said second tubular member resides within the first cavity and is coaxial to the first tubular member; and a double conic body coaxially residing in the first cavity and coaxially positioned with the second tubular member.

Also provided is a method for removing heat from a building, the method having the steps of: directing heat-containing exhaust emanating from a flue, defining a first diameter, to a passageway received by the flue, whereby the passageway defines a longitudinal axis and a periphery circumscribing the axis; forming the directed exhaust into a slipstream, wherein the slipstream generally travels along the longitudinal axis; and routing precipitation entering the passageway to the periphery.

An exhaust flue cap and filter device for a gas fired appliance in communication with an exhaust flue opening. The device includes an inner collar to engage the exhaust flue opening. A tubular cap with a closed lower end is in communication with the inner collar. A filter tray is suspended in the tubular cap wherein the filter tray has a smaller diameter than the tubular cap so that a bypass space is formed between the filter tray and the tubular cap to permit passage of exhaust gases. A removable filter insert is receivable in the filter tray. A removable top having a body with exhaust openings is attached to and closes the open upper end of the tubular cap.

An exhaust flue cap and filter device for a gas fired appliance in communication with an exhaust flue opening. The device includes an inner collar to engage the exhaust flue opening. A tubular cap with a closed lower end is in communication with the inner collar. A filter tray is suspended in the tubular cap wherein the filter tray has a smaller diameter than the tubular cap so that a bypass space is formed between the filter tray and the tubular cap to permit passage of exhaust gases. A removable filter insert is receivable in the filter tray. A removable top having a body with exhaust openings is attached to and closes the open upper end of the tubular cap.