Self-Contained Positive Pressure Air Breathing Apparatus

The positive pressure breathing apparatuses are self-contained open breathing apparatuses. This series of products, which are ideal personal breathing protectors for the fireman and emergency rescuer, are widely used in such sectors as fire fighting, chemical industry, shipping, petroleum, smelting, electricity, warehouse, lab, mine, for the fireman and emergency rescuer to perform effectually rescue and relief work under the conditions of heavy smoke, poison gas, steam and hypoxia, etc.

General Description:
1. The regulator is a two-stage device. A balanced first stage provides a uniform pressure to the second stage admission valve. The second stage provides air at a breathable flow rate to the user. The regulator has two distinctly-shaped, hand-operated valves. The gold, knurled knob operates the main-line valve. This valve lets air flow from the regulator to the face piece. The valve is quick-acting, requiring only ¼ Turn to obtain full air flow. Once opened, the valve remains open until the release button is pressed and the knob is turned clockwise. The red, hex-head knob operates the by-pass valve. The valve knob's distinctive red color and hex shape permit quick identification. The by-pass valve is used only if the main-line valve fails or the regulator fails while the apparatus is in use.

2. The air cylinder and valve consist of a tank and a cylinder valve assembly. The cylinder valve includes a valve body, cylinder valve inlet tube, hand wheels, safety disc (burst disc), and pressure gauge. The pressure gauge shows the air pressure in the cylinder continuously. The gauge is calibrated in 100 PSIG increments. For example, a gauge reading of 20 is read as 20 *100 or 2, 000 PSIG. A hand wheel is used to open and close the cylinder.

3. The face piece lens is super-hard coated to meet the requirements of NFPA 198. This process gives the clear polycarbonate lens superior abrasion and chemical protection. The face piece has a low-resistance, pressure-demand exhalation valve designed for easy cleaning. An inhalation check valve in the inlet housing keeps moisture out of the diaphragm for clear, short range communication. The face piece includes a standard five-point adjustment rubber head harness made of flame and heat resistant (FHR) materials, and features a five-point suspension. Five "points" use self-adjusting, elasticized straps. The breathing tube carries air from the regulator to the face piece. The regulator end of the tube has a metal coupling nut and an insert to guide the coupling nut into the regulator outlet. The face piece end of the breathing tube has a threaded insert to match the face piece coupling nut.

4. The Audi-Larm audible alarm rings when there is approximately 25% of the SCBA's rated service time remaining. The alarm also rings when the cylinder valve is first opened, providing an audible indication that the alarm is properly "cocked". The high-pressure hose delivers air at cylinder pressure from the alarm to the first stage regulator.

5. The carrier and harness consists of a back plate, a cylinder band and a latch to hold the cylinder, and a harness, consisting of shoulder pads, a chest strap, adjustable pull-straps, and a waist-strap.


The self-contained breathing apparatus consists of the following sub-assemblies: Pressure Demand Regulator
Air Cylinder and Valve
Face piece and Breathing Tube
Carrier and Harness
Pressure Gauge