A gas mask is a device that protects the skin of the face and respiratory system from exposure to volatile toxic chemicals. An isolating device serves as an obligatory set of equipment for both military and civilians working in hazardous industries or exposed to toxic substances. It is used by workers involved in the aftermath of technological disasters. Let's take a closer look at the hose gas mask device.
What is a gas mask?
The first protective devices used in Russia, historians consider the glass caps that the masters put on when gilding the domes of St. Isaac's Cathedral in the northern capital. That was in 1838. The process used mercury, and thus wanted to protect workers from inhaling its vapors. However, through the hoses through which air was supplied, it is clear that the couples nevertheless passed, because more than 60 people died in construction work.
There are two types of modern gas mask: filtering and completely insulating. The latter is represented by several types, but their structure is similar. They serve to protect the respiratory tract, eyes, skin from any poisonous and dangerous substances for the human body, regardless of their concentration in the air. The principle of operation of any insulating gas mask is based on the action of a regenerative cartridge, which is equipped with a special substance.
The IP-46M gas mask is used even for short-term work under water or in a flooded tank. Its device allows you to clean the air of carbon dioxide and enrich it with oxygen. The whole process takes place in a regenerative cartridge.
Gas mask structure
An insulating gas mask has the following structure:
- Front part. It isolates the respiratory tract and the entire face from the surrounding aggressive environment, directing the air exhaled by a person into a regenerative cartridge and, conversely, leads the air cleaned there from carbon dioxide back into the respiratory system.
- Starting briquette. In the first minutes of using a gas mask, it provides a breathing process and automatically activates the cartridge.
- Insulating cover. Without it, the exchange of air mixtures is not so intense, especially when you have to work under water. The cartridge emits less oxygen so necessary for the life of the body, and a person will feel an acute shortage of air. The cover is removable.
- Breathing bag. It is a spacious reservoir for air when inhaling and exhaling. It connects the front part and the regenerative cartridge from the gas mask. Made from rubberized fabric. It has a valve to eliminate excess pressure and nipples to connect to the rest of the device.
- Valves The direct valve serves to let the exhaled air out of the breathing bag. Reverse - to protect against accidental ingress of air from the surrounding atmosphere or water when working under water.
- Wireframe. Protects the air bag from being squeezed and mechanically damaged during use.
- A bag. A protective device is stored there during carrying or for saving. It protects the product from damage. In the same pocket, additional anti-fog films for glasses are stored in the inner pocket.
- The main protective device is a regenerating cartridge. It is about him that will be discussed later in the article.
Cartridge RP-4
This cartridge has the shape of a cylinder. Its dimensions are as follows: height - 25 cm and diameter - 12.5 cm. The starting briquette is located in this model in the cartridge itself. It serves for inhalation at the very beginning, when putting on a gas mask. Next, the starting device starts the action of the regenerative cartridge itself. It contains an ampoule with sulfuric acid, as well as a special device for breaking it.
When assembled, it is placed in the nest of the frame. Let us consider its structure in more detail.
Cartridge structure
The regenerative cartridge arrangement is described in detail below. It has a metal case with two covers. The inside is filled with a substance containing oxygen. On the covers there are necks and a starting device.
On the upper part of the cartridge there is a neck for connecting the cartridge to the connecting tube and mask-helmet through a nipple device. The second neck is called navnite. It is adapted for the starting nut of the starting briquette, which has a pin and seal.
Under it, inside the RP-4 cartridge case, there is a cylindrical mesh block in which a starting briquette with a glass ampoule containing sulfuric acid is placed. The bottom of the cartridge case also has a neck through which it joins the breathing bag. Before collecting a gas mask, all the plugs of the cartridge are removed, make sure that they are sealed.
Marking on this cartridge is applied with waterproof mastic to the cylindrical part. First, the name of the product is written - RP-4; then - the symbol of the company where the cartridge is made (in numbers), month and year (last 2 digits), batch number; the last line is the cartridge number in this batch.
Principle of operation
The basic principle of the hose gas mask cartridge is based on the absorption of moisture and carbon dioxide, which are formed during human breathing, and the release of oxygen cartridge using a special filling (regenerative product). When breaking an ampoule, sulfuric acid heats this substance and starts the oxygen evolution reaction. Up to this point, the starting briquette provides oxygen during inspiration.
After crushing the ampoule with acid, it falls alternately on all layers, causing decomposition of the briquette. In this case, a chemical reaction takes place, as a result of which oxygen, steam and heat are released. It is steam and heat that cause the reaction of the substance in the cartridge. After the formation of oxygen, it enters the breathing bag, the connecting tube and the helmet-mask, through which air flows into the respiratory tract.
Time of action
In order to perform work in an insulating gas mask, the oxygen produced in the cartridge is enough for a short time. If a person is at rest, then air enriched with oxygen will last for three hours. If a person has to do the work, then the time of using the cartridge is significantly reduced, since breathing during exercise occurs more intensively. For example, with medium physical loads, the RP-4-01 cartridge will last for 70 minutes, and with heavy loads - for 45 minutes at all.
But even if you replaced the regenerating cartridge in an isolating gas mask, then the maximum allowable working norms in it are 8 hours. The device can be operated from -40 ° C to +40 ° C in hot conditions. Be sure to check the shelf life. Such products are used extremely rarely, except on training tasks, so you need to carefully check the expiration date of the cartridge periodically. Its action is limited to a period of 7 years. Then you have to replace it.
RP-46
Such a regenerating cartridge was developed back in 1946 for an insulating gas mask of the IP-46 and IP-46M brands. Issued to this day. The design and principle of operation of the regenerative cartridge is similar to the previous sample, but there are still differences. They will be discussed later in the article.
It has an unlimited shelf life, unlike the previous one, but it must be checked every five years for mechanical damage and the integrity of the seal. Cartridges that have no visible signs of corrosion are considered suitable; a change in initial weight of 20% is permissible.
Since the reactions in it are exothermic, the cartridge can be heated to high temperatures (90-100 degrees Celsius) during operation, so you need to wear it only in a special case with a gasket that protects the human body from burns.
The main difference from RP-4 is that the starting briquette is stored separately from the cartridge. This protects it from spontaneous inclusion. When starting work with an insulating gas mask, unscrew the start-up unit and place the start-up briquette in the hole. Then the cartridge is attached to the gas mask and the striker is pressed on the launch site.
Then, in the RP-46 cartridge, the same process of breaking the ampoule and the reaction of oxygen evolution occurs.
Signs of the end of the cartridge
It is worth the alarm in such cases:
- If it becomes difficult to take a full breath while doing work with the same effort.
- Incomplete filling of the respiratory bag of the gas mask.
- If a person begins to feel discomfort: feeling sick, nausea, persistent headache and beginning dizziness.
If you feel these signs, then you need to replace the cartridge with a new one. It is forbidden to work in a gas mask until the cartridge is fully used. It must be changed at the first sign of oxygen depletion. Failure to comply with this safety requirement may result in loss of consciousness and subsequent strangulation of the employee.
Work safety measures
Before putting on a gas mask in working conditions, you must undergo mandatory training, a course of training, as well as a medical examination. Before starting operation, it is necessary to check the serviceability of the gas mask, its proper assembly and cartridge integrity.
If the cartridge has a malfunction, it must be replaced with a new one. Also, be sure to check the tightness of the starting briquette. You cannot work alone. In the room where work is carried out, there must be at least two people in gas masks.
First you need to make sure that the trigger has worked and oxygen has begun to be released. Only then enter the room with toxic substances. If you had a break in work with removing the helmet-mask from the head, then don’t put it back on. First you will need to replace the cartridge with a new one.
Constantly monitor your well-being and at the first signs that the cartridge’s action is ending, you need to replace it with a new one.
Protect the body from burns when heating the cartridge, especially when it is being changed.
Do not allow water or other organic substances to fall on the cartridge at the time the gas mask is prepared for use. Also, an additional portion of oxygen should not fall on the starting briquette.
Absolutely forbidden
Storage of regenerative cartridges is prohibited when assembled at a temperature of +35 ° C, in direct sunlight, near heating appliances, near combustible substances. Spent cartridges must be stored separately from new ones. Do not use lubricants when preparing a gas mask. If the regenerative cartridge was in use, it can no longer be reused. Do not take into work cartridges in which the seal is broken.
The replacement of the spent cartridge cannot be carried out in an aggressive environment, only in case of emergency. It is forbidden to wear a gas mask at a temperature below 40 degrees.
Disposal
To protect the environment, used regenerative recycling cartridges. They can’t just be buried or burned. Inorganic compounds must be completely neutralized by adding crystalline calcium chloride and distilled water to the briquette. After the reaction, the layers are filtered and dried. This is a complex process that takes a long time and in laboratory conditions.