Provided is a blower installed at a manhole opening, with which it is possible to facilitate an entry or an exit of a worker or an import or an export of an article. The present invention provides a ventilation system comprising a frame and a single or a plurality of airflow generation means arranged at the frame, a direction of an airflow is adjusted so that the airflow generated from the airflow generation means flows along with a virtual axis penetrating a virtual surface which the frame is regarded as to periphery, and the airflow flows while swallowing up the surrounding air of the virtual axis, and an air volume more than two times of total fluid volume of the airflow is generated.

A split air cabin ventilation system for construction of tunnel inclined shafts, including a first air cabin and a second air cabin which are both in a hollow closed structure with an air inlet end and an air outlet end respectively at both sides. The two air outlet ends are arranged away from each other. An end of the split air cabin is provided with an air inlet, and the other end is provided with an air outlet. The air inlet is connected to an air source, and the air outlet is connected to the air inlet ends of the first and second air cabins, respectively. The air inlet end of the first air cabin is connected to another air source.

Provided is a method of mining a single steeply-inclined thick coal seam, which belongs to the mining engineering field. The mining method includes: carrying out one transport crossheading along a floor of the coal seam to constitute a production system together with rises on both sides of a district; arranging a top-coal caving hydraulic support along a thickness of the coal seam in the transport crossheading, with a cyclic advance interval being 1.0 m; maintaining one section of return air channel close to a side of a roof that is in a gob and behind the hydraulic support. In a case of mining, caved coals fall on a scraper conveyer and transported through a belt conveyer. Fresh air flow required for a working surface enters the transport crossheading through a district transport crosscut and a track rise, and then enters the return air rise through the return air channel after washing the working surface. A unique return air channel is adopted. The method features advantages such as simple roadway arrangement system, strong adaptability, large yield of working surface, and high safety level.

Provided is a method of mining a single steeply-inclined thick coal seam, which belongs to the mining engineering field. The mining method includes: carrying out one transport crossheading along a floor of the coal seam to constitute a production system together with rises on both sides of a district; arranging a top-coal caving hydraulic support along a thickness of the coal seam in the transport crossheading, with a cyclic advance interval being 1.0 m; maintaining one section of return air channel close to a side of a roof that is in a gob and behind the hydraulic support. In a case of mining, caved coals fall on a scraper conveyer and transported through a belt conveyer. Fresh air flow required for a working surface enters the transport crossheading through a district transport crosscut and a track rise, and then enters the return air rise through the return air channel after washing the working surface. A unique return air channel is adopted. The method features advantages such as simple roadway arrangement system, strong adaptability, large yield of working surface, and high safety level.

An assembly that fits within a ventilation shaft open to atmosphere and leading from underground ventilation ducts such as to subways prevents surface waters from flooding the underground ducts while maintaining the ventilation. The assembly fits in the ventilation shaft and houses a buoyant float in a chamber surrounding a passageway in fluid communication with the ventilation shaft. A grate covers the passageway. An outside wall of the chamber adjacent the ventilation shaft is open at top to atmosphere and allows flooding water into the chamber, buoying the float upward in the chamber, elevating the passageway above the flooding water. The chamber suitably has means for drainage and admission of flush water to flush flood water debris from the chamber through the drainage.

An assembly that fits within a ventilation shaft open to atmosphere and leading from underground ventilation ducts such as to subways prevents surface waters from flooding the underground ducts while maintaining the ventilation. The assembly fits in the ventilation shaft and houses a buoyant float in a chamber surrounding a passageway in fluid communication with the ventilation shaft. A grate covers the passageway. An outside wall of the chamber adjacent the ventilation shaft is open at top to atmosphere and allows flooding water into the chamber, buoying the float upward in the chamber, elevating the passageway above the flooding water. The chamber suitably has means for drainage and admission of flush water to flush flood water debris from the chamber through the drainage.

Apparatus allowing ventilation through a ventilation shaft to an underground ventilation duct fluidly communicating through the ventilation shaft to an atmospheric opening of the shaft and on threat of flooding operable to prevent downward flow of surface water into the ventilation duct includes support sidewalls fitting in the shaft providing a ventilation passage between support top and bottom openings and a suspension member supported on opposed lateral sidewalls proximate the top opening holding one or more hinge connected panels that manually release to rotationally close the passage and are manually rotationally liftable to a home position allowing ventilation. A panel drain automatically closes when the panel is raised to home position so it is already closed when the panel is released to rotationally close the passage.

Apparatus allowing ventilation through a ventilation shaft to an underground ventilation duct fluidly communicating through the ventilation shaft to an atmospheric opening of the shaft and on threat of flooding operable to prevent downward flow of surface water into the ventilation duct includes support sidewalls fitting in the shaft providing a ventilation passage between support top and bottom openings and a suspension member supported on opposed lateral sidewalls proximate the top opening holding one or more hinge connected panels that manually release to rotationally close the passage and are manually rotationally liftable to a home position allowing ventilation. A panel drain automatically closes when the panel is raised to home position so it is already closed when the panel is released to rotationally close the passage.

Apparatus allowing ventilation through a ventilation shaft to an underground ventilation duct fluidly communicating through the ventilation shaft to an atmospheric opening of the shaft and on threat of flooding operable to prevent downward flow of surface water into the ventilation duct includes support sidewalls fitting in the shaft providing a ventilation passage between support top and bottom openings and a suspension member supported on opposed lateral sidewalls proximate the top opening holding one or more hinge connected panels that manually release to rotationally close the passage and are manually rotationally liftable to a home position allowing ventilation. A releasable latching system between panel and a suspension member holder catches rising panels to hold them in home position ready for release.

Apparatus allowing ventilation through a ventilation shaft to an underground ventilation duct fluidly communicating through the ventilation shaft to an atmospheric opening of the shaft and on threat of flooding operable to prevent downward flow of surface water into the ventilation duct includes support sidewalls fitting in the shaft providing a ventilation passage between support top and bottom openings and a suspension member supported on opposed lateral sidewalls proximate the top opening holding one or more hinge connected panels that manually release to rotationally close the passage and are manually rotationally liftable to a home position allowing ventilation. A releasable latching system between panel and a suspension member holder catches rising panels to hold them in home position ready for release.