A mask structure with an externally connected filtering device includes a mask body, a unidirectional air seat valve, at least one connecting tube and a filtering device. The mask body is made of an air-impermeable material, can be provided with the unidirectional air seal valve thereon and connected with the filtering device through the connecting tube, so that the mask structure can filter and purify ambient air by the filtering device, and deliver the filtered air to the inner side of the mask body through the connecting tube for a user to inhale. The exhaled air by the user can be expelled through the unidirectional air seal valve to the outer side of the mask body.

A mask structure with an externally connected filtering device includes a mask body, a unidirectional air seat valve, at least one connecting tube and a filtering device. The mask body is made of an air-impermeable material, can be provided with the unidirectional air seal valve thereon and connected with the filtering device through the connecting tube, so that the mask structure can filter and purify ambient air by the filtering device, and deliver the filtered air to the inner side of the mask body through the connecting tube for a user to inhale. The exhaled air by the user can be expelled through the unidirectional air seal valve to the outer side of the mask body.

The PAPR frame is a low cost solution that allows the assembly of a PAPR device from readily available off-the-shelf elements. To assemble the PAPR device, a face shield is inserted into the PAPR frame. To utilize the PAPR device, a user inserts the visor of a hat into the PAPR frame and wears the hat. The PAPR device may further include tubing segments; the tubing segments are inserted into tubing apertures arranged through a top curved piece of the PAPR frame. The PAPR device may also further include one or two sound attenuation structures, which are used to dampen the potential noise generated by the air flow within the PAPR device.

The PAPR frame is a low cost solution that allows the assembly of a PAPR device from readily available off-the-shelf elements. To assemble the PAPR device, a face shield is inserted into the PAPR frame. To utilize the PAPR device, a user inserts the visor of a hat into the PAPR frame and wears the hat. The PAPR device may further include tubing segments; the tubing segments are inserted into tubing apertures arranged through a top curved piece of the PAPR frame. The PAPR device may also further include one or two sound attenuation structures, which are used to dampen the potential noise generated by the air flow within the PAPR device.

A personal protected-air system includes first and second rings, and a sleeve coupled on each end thereof to one of the rings. The first ring includes a port for receiving filtered air under pressure, a manifold in fluid communication with the port, and vents in fluid communication with the manifold and the interior region of the sleeve. The sleeve includes a transparent region. In use, the second ring fits over a user's head, the sleeve encases the user's head, and the first ring rests on a top portion of the user's head. The second ring includes an air passage providing fluid communication between an ambient environment and the interior region of the sleeve.

A personal protected-air system includes first and second rings, and a sleeve coupled on each end thereof to one of the rings. The first ring includes a port for receiving filtered air under pressure, a manifold in fluid communication with the port, and vents in fluid communication with the manifold and the interior region of the sleeve. The sleeve includes a transparent region. In use, the second ring fits over a user's head, the sleeve encases the user's head, and the first ring rests on a top portion of the user's head. The second ring includes an air passage providing fluid communication between an ambient environment and the interior region of the sleeve.

A gas guide apparatus provides a user with a comfortable feel during use of a mask or the like. The gas guide apparatus includes a gas supply unit configured to supply a gas, a gas supply side tube unit configured to have a supply hole to emit the gas supplied from the gas supply unit outside, and a disposition unit configured to dispose the gas supply side tube unit on a face of a user with the supply hole opposed to the mouth vicinity area in front of the mouth of the user.

A gas guide apparatus provides a user with a comfortable feel during use of a mask or the like. The gas guide apparatus includes a gas supply unit configured to supply a gas, a gas supply side tube unit configured to have a supply hole to emit the gas supplied from the gas supply unit outside, and a disposition unit configured to dispose the gas supply side tube unit on a face of a user with the supply hole opposed to the mouth vicinity area in front of the mouth of the user.

A personal breathing system incorporating a phased-dilution demand oxygen regulator (PDDOR) is disclosed. In embodiments, the breathing system includes a pressurized oxygen source and oronasal mask, a dilution valve for supplying ambient air and a demand valve for supplying pure oxygen. The PDDOR senses the mask pressure associated with the start of an inhalation cycle, maintaining pressure to the demand valve through an initial demand phase during which 100% pure oxygen is supplied through the demand valve. Control pressure within the PDDOR drops throughout the initial demand phase; when the pressure drops below a lower threshold the PDDOR main valve is closed, blocking the demand valve and cutting off the oxygen supply. Ambient air is provided to the mask via a dilution valve to preserve flow to the user.

A personal breathing system incorporating a phased-dilution demand oxygen regulator (PDDOR) is disclosed. In embodiments, the breathing system includes a pressurized oxygen source and oronasal mask, a dilution valve for supplying ambient air and a demand valve for supplying pure oxygen. The PDDOR senses the mask pressure associated with the start of an inhalation cycle, maintaining pressure to the demand valve through an initial demand phase during which 100% pure oxygen is supplied through the demand valve. Control pressure within the PDDOR drops throughout the initial demand phase; when the pressure drops below a lower threshold the PDDOR main valve is closed, blocking the demand valve and cutting off the oxygen supply. Ambient air is provided to the mask via a dilution valve to preserve flow to the user.