Abstract: Positive pressure respirators are self-contained open air respirators that can prevent firefighters and emergency rescue personnel from inhaling poisonous gases, smoke, and suspended in the air that are harmful to the human body during fire fighting or rescue operations. harmful pollutants. It can also be used in hypoxic environments to prevent inhalation of toxic gases, thereby effectively carrying out fire extinguishing, emergency rescue and disaster relief, and labor operations. The positive pressure respirator consists of a mask, a gas cylinder, a bottle belt set, a shoulder strap, an alarm whistle, a pressure gauge, a cylinder valve, a pressure reducer, a back support, a belt set, a quick connector, a supply valve and other parts. Let’s take a look at the introduction below. 1. Components of positive pressure respirator
Mask: It is a large viewing window. The window lens is made of polycarbonate material, which has high transparency, strong wear resistance, anti-fog function and mesh shape. The hood-type wearing method is comfortable and convenient to wear. The colloid is made of silicone, which is non-toxic, odorless, non-irritating and has good air-tightness.
Gas cylinder: It is an aluminum-lined carbon fiber fully wound composite gas cylinder with a working pressure of 30MPa. It has light weight, high strength and good safety performance. The bottle valve has a high-pressure safety protection device.
Bottle belt group: The bottle belt card is a quick cam locking mechanism and ensures that the bottle belt is always in a closed loop state. The cylinder will not flip over.
Shoulder straps: Made of flame-retardant polyester fabric, the straps adopt a bilaterally adjustable structure to place the weight on the waist and hips, reducing the pressure of the shoulder straps on the chest and making breathing smoother. And there are large elastic pads on the shoulder straps to reduce pressure on the shoulders.
Alarm whistle: placed on the chest, the alarm sound is easy to distinguish, small in size and light in weight.
Pressure gauge: large dial, night vision function, equipped with rubber protective cover.
Gas cylinder valve: It has a high-pressure safety device and small opening torque.
Pressure reducer: small size, large flow rate, stable output pressure.
Backrest: The backrest is designed in line with ergonomic principles and is made of carbon fiber composite injection molding. It has flame retardant and anti-static functions. It is light and strong. The inside of the backrest is lined with elastic pads. Makes the wearer comfortable.
Belt set: buckled and easy to adjust.
Quick connector: compact, can be operated with one hand, and has a locking and anti-loosening function.
Supply valve: simple structure, strong functionality, large output flow, bypass output, small size.
2. How to use the positive pressure respirator
1. When wearing, first disconnect the quick connector (to prevent damage to the full face mask when wearing), and then put the back support On the back of the human body (the air bottle switch is at the bottom), adjust the shoulder straps and waist belt according to the body shape and tighten them to make them fit, secure and comfortable.
2. Put the long strap on the full-face mask around your neck. Place the full-face mask on your chest before use so that you can wear it at any time, and then quickly connect the connectors.
3. Set the switch of the supply valve to the off position and turn on the air bottle switch.
4. Wear a full-face mask (no straps required) and take 2 to 3 deep breaths. You should feel comfortable. When holding your breath or exhaling, the supply valve should stop supplying air without making a "hissing" sound. Press the lever of the supply valve with your hand to check whether it opens or closes flexibly. When everything is normal, tighten the straps of the full-face mask to an appropriate degree to ensure airtightness, comfort, and no obvious tenderness.
5. After evacuating the scene and arriving at a safe place, loosen the strap clips of the full-face mask and take off the full-face mask.
6. Turn off the gas cylinder switch, open the supply valve, unplug the quick connector, and remove the respirator from the body.
3. How to perform safety inspections on positive pressure respirators
First, keep the mirror surface of the full-face mask clean. When operators need to use a positive pressure air respirator, they must pay attention to check several related parts. These parts include the lens of the full face mask. We need to ensure that the entire lens is clean. Of course, in addition to being free of dust, The full face mask of the respirator cannot be contaminated by relevant harmful substances, including acidity, alkalinity, and relatively oily substances, which cannot be on the mirror surface. The mirror surface needs to be kept clean at all times.
Second, ensure the flexibility of key valves. The positive pressure air respirator has two key valves, namely the inhalation valve and the exhalation valve. These two valves directly affect the later use of the positive pressure air respirator. We must ensure that the entire valve The action switch is flexible. In particular, attention needs to be paid to the stability of the connection between the valve and the conduit, which are very critical aspects.
Third, regarding the air density detection of the entire positive pressure air respirator, this is a very critical aspect. We must ensure that the air density of the entire positive pressure air respirator should be normal. In this case, the simple detection method is to open the bottle head valve. As the pressure in the pipeline and pressure reducing system rises, you will hear a short sound from the gas source residual pressure alarm; after the bottle head valve is fully opened, check the gas cylinder. The pressure inside should be within the range of 28Mpa ~ 30Mpa.