Surgery – Respiratory method or device – Means for supplying respiratory gas under positive pressure
Reexamination Certificate
2002-10-03
2004-11-30
Dawson, Glenn K. (Department: 3761)
Surgery
Respiratory method or device
Means for supplying respiratory gas under positive pressure
C128S200240, C128S202130, C128S204180, C383S041000, C383S060000
Reexamination Certificate
active
06823867
ABSTRACT:
The present invention relates to respirator systems of the type commonly known as powered air-purifying respirators (PAPRs).
A PAPR employs a blower to supply filtered air to a respiratory mask that is worn by the user. The blower and air filter(s) are often provided in a separate unit that is remote from the respiratory mask and connected to the latter by a breathing tube or hose. The blower unit may be designed to be carried by the wearer (for example, on a belt at the waist) and will then typically also include a battery pack and related electronic control units to provide an independent power supply for the blower. When a PAPR is in use, filtered air is supplied continuously by the blower to the respiratory mask under positive pressure and causes spent air within the mask to be expelled. A PAPR system is distinguished from a non-powered respirator in which filtered air is drawn into, and expelled from, the respiratory mask by the wearer's own breathing action.
PAPRs are often used in industrial applications where the respiratory hazards are well-defined and quantified. Those respiratory hazards might include, for example, harmful gases and particulate matter and, when they are anticipated, a PAPR can be configured before a user enters the hazardous environment. It is then very desirable that there is a high degree of flexibility in how the PAPR can be configured so that the user can select in advance not only the appropriate filters for the anticipated hazards but also the preferred blower unit, breathing tube and respiratory mask.
PAPRs are also used in emergency situations by emergency response units (e.g. police, fire and civil defence units). In those circumstances, there is a need to be able to configure (and, if necessary, adapt) a PAPR quickly so that it can cope with the demands of a particular situation.
PAPRs can be required to be used in environments for which so-called “intrinsically-safe” equipment is specified (that is, equipment that is protected to a prescribed level against the ingress of a potentially explosive material in the form of gas or dust). The purpose of this is to reduce the risk of an explosion due to sparks or heat that may be generated by components within the equipment and, in the case of the blower unit of a PAPR, intrinsic safety requirements are often addressed through the provision of a unit that has been specifically-designed for this purpose. Such specifically-designed units are, however, generally more expensive than standard blower units and, for the user, it would often be more attractive to be able to up-grade a standard blower unit, provided it is dust-free (i.e. has not already been exposed to a contaminated environment) quickly and easily to an intrinsically-safe level whenever required.
PAPRs can also be required to be used in environments containing contaminating materials (for example, chemical or biological contaminants). In those cases, the PAPR must either be carefully disposed of after use (which is expensive and undesirable for environmental reasons), or carefully cleaned to remove the contaminating material. The latter course, although potentially less expensive, is time-consuming and it would clearly be advantageous if the cleaning time could be reduced. Alternatively, in the case in which the user of a PAPR is required to wear some form of protective clothing (e.g. a protective suit), it is also known to place the blower unit and breathing tube of the PAPR inside the suit although it is then less accessible. WO01/74449, for example, describes a protective suit having a harness-borne pump unit positioned inside the suit.
The present invention is concerned with enabling the blower unit of a PAPR (provided it has not already been contaminated) to be upgraded to an intrinsically-safe level quickly and easily and at comparatively low cost. It is further concerned with enabling the time required to clean a PAPR after use in a contaminated environment to be reduced.
In accordance with the invention, a pouch is provided into which the blower unit can be placed with a view to preventing the unit from being exposed to a particular hazardous material or with a view to preventing the entry of a particular hazardous material into the unit.
The present invention provides a pouch for the blower unit of a powered air-purifying respirator system, the blower unit being of a type comprising:
(a) an air inlet to which a filter cartridge can be detachably-connected,
(b) an air outlet to which a breathing tube of the respirator system can be detachably-connected, and
(c) a blower operable to draw air into the unit through the air inlet and to deliver filtered air to the air outlet;
wherein the pouch comprises;
(i) a closable main opening through which the blower unit can be inserted into the pouch,
(ii) an air inlet opening positioned to register with the air inlet of the blower and permit the connection of the filter cartridge thereto,
(iii) an air outlet opening positioned to register with the air outlet of the blower unit and permit the connection of the breathing tube thereto, and
(iv) respective sealing means for each of the said openings;
the sealing means being so configured that, when the blower unit is located inside the closed pouch and is connected into the respirator system, they inhibit or prevent the passage of particulate or gaseous material into the pouch through the said openings.
The present invention also provides a method of protecting the blower unit of a powered air-purifying respirator system against the entry into the unit of particulate or gaseous material, the blower unit being of a type comprising:
(a) an air inlet to which a filter cartridge can be detachably-connected,
(b) an air outlet to which a breathing tube of the respirator system can be detachably-connected, and
(c) a blower operable to draw air into the unit through the air inlet and to deliver filtered air to the air outlet;
the method comprising the steps of;
(i) placing the blower unit inside a pouch,
(ii) connecting the air inlet to the filter cartridge through an opening in the pouch,
(iii) connecting the air outlet to the breathing tube through an opening in the pouch, and
(iv) providing sealing means at the openings in the pouch to inhibit or prevent the passage of particulate or gaseous material into the pouch through the said openings.
The present invention further provides a respirator system comprising:
a respiratory mask,
a blower unit having an air inlet, an air outlet and a blower operable to draw air into the unit through the air inlet and to air to the air outlet,
a pouch within which the blower unit is located,
a filter cartridge detachably-connected to the air inlet of the blower unit through an opening in the pouch, and
a breathing tube detachably-connected at one end to the air outlet of the blower unit through an opening in the pouch, and connected at the other end to the respiratory mask;
respective sealing means for each of the said openings;
wherein the openings in the pouch are provided with sealing means that inhibit or prevent the passage of particulate or gaseous material into the pouch through the said openings.
Pouches have previously been provided for PAPR blower units to protect the casings of the units against damage (e.g. being scratched or otherwise marked) during use. A pouch of that type would not inhibit or prevent the passage of particulate or gaseous material into the blower unit and would not enable the blower unit of a PAPR (provided it has not already been contaminated) to be upgraded to an intrinsically-safe level.
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patent: 3786809 (1974-01-01), Kitrilakis
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patent: 5309901 (1994-05-01), Beaussant
patent: 5339806 (1994-08-01), Beaussant et al.
patent: 2002/0112754 (2002-08-01), Gauger et al.
patent: 156463 (1982-09-01), None
patent: 0 211 914 (1988-10-01), None
patent: 0 353 417 (1992-11-01), None
patent: 2 565 662 (1985-12-01), None
“3M Safety: 3M™ Spark Arrest Cover GVP-146 1/Case”, downloaded from the internet at http://products3.3m.com/catalog/us
Avery Martin J.
Curran Desmond T.
Gloag Nicholas J.
Graves Jason A.
Johnson Rachael J.
3M Innovative Properties Company
Dawson Glenn K.
Hanson Karl G.
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