Respirator with end-of-service-life detection

A respirator comprising:

• a respirator housing for providing cleaned air to a user;
• a pump for pumping cleaned air from the respirator housing to the user;
• a first respiratory cartridge connectable to the respirator housing, the first respiratory cartridge receiving ambient air and delivering cleaned air to the respirator housing;
• a second respiratory cartridge connectable to the respirator housing, the second respiratory cartridge receiving ambient air and delivering cleaned air to the respirator housing;
• a third respiratory cartridge connectable to the respirator housing, the third respiratory cartridge receiving ambient air and delivering cleaned air to the respirator housing;
• the first respiratory cartridge having a lower adsorption capacity for a targeted gas than the second respiratory cartridge and the third respiratory cartridge;
• a tube fluidly interposed between an outlet of the first respiratory cartridge and the respirator housing;
• a gas sensor exposed to an interior of the tube;
• a valve for selectively closing off the tube;
• and
• a controller coupled to the gas sensor and the valve, wherein the controller closes the valve when the gas sensor detects an increased concentration of the targeted gas in the tube, the controller also issues an end-of-service-life indication to the user when the gas sensor detects an increased concentration of the targeted gas in the tube;
• and
• wherein a flow through the second respiratory cartridge and/or the third respiratory cartridge is increased when the gas sensor detects an increased concentration of the targeted gas in the tube.

A method for providing cleaned air to a user, comprising:

• passing ambient air through two or more respiratory cartridges into a respirator housing, wherein a first one of the two or more respiratory cartridges has a lower adsorption capacity for a targeted gas than at least one other of the two or more respirator cartridges;
• using a gas sensor positioned downstream of the first one of the two or more respiratory cartridges to detect an increased concentration of the targeted gas in air cleaned and delivered by the first one of the two or more respiratory cartridges to the respirator housing;
• detecting with the gas sensor when the first one of the two or more respiratory cartridges has a targeted gas break through;
• increasing a flow rate of air through the at least one other of the two or more respiratory cartridges after the gas sensor has detected that the first one of the two or more respiratory cartridges has the targeted gas break through;
• and
• issuing an end-of-service-life indication to the user when the gas sensor has detected that the first one of the two or more respiratory cartridges has the targeted gas break through.

A respirator comprising:

• a respirator housing for providing cleaned air to a user;
• a first respiratory cartridge and a second respiratory cartridge removably connected to the respirator housing, the first and second respiratory cartridges receiving ambient air and delivering cleaned air to the respirator housing;
• the first respiratory cartridge having a lower adsorption capacity for a targeted gas than the second respiratory cartridge;
• a gas sensor positioned downstream of the first respiratory cartridge configured to detect an increased concentration of the targeted gas in the cleaned air delivered by the first respiratory cartridge to the respirator housing;
• a tube fluidly interposed between an outlet of the first respiratory cartridge and the respirator housing;
• a valve positioned downstream of the gas sensor for selectively closing off the tube;
• and
• wherein a flow through the second respiratory cartridge increases when the gas sensor detects an increased concentration of the targeted gas.