Explosion-proof camera

Explosion-proof camera knowledge guide First, the explosion-proof camera has explosion-proof grade Chinese national standard "GB3836.1-2000 Explosive gas environment electrical equipment" and other "GB3836.2-9" standard, there is a clear definition of explosion-proof grade. And most of the explosion-proof grade parameters formulated by China are higher than European, American and international standards, which shows that China's management of explosion-proof equipment is very strict.

Explosion-proof cameras, by definition, can prevent explosions. However, many contractors accurately told the company that they had a normal riot camera. The camera's power supply was a weak 12V and it would not catch fire or explode. I can't evaluate it with ignorance, but he certainly does not have a good understanding of what the “explosion” should be.

In fact, the “explosion” and the “burning” required are almost the same. Three conditions must be met at the same time. First, there must be explosive substances or flammable substances; second, there must be flammable substances, mainly in the air. Oxygen; third, there is also a source of ignition (such as sparks, arcs, and dangerous temperatures, etc.) that provide the necessary energy to ignite the mixture. Only if these three conditions exist at the same time will there be the possibility of an explosion. If any one of these conditions is not available, there will be no combustion or explosion.

In the mine, the first two conditions are basically met. The third condition comes from the camera introduced by the project engineer. Because the sealing performance of the ordinary camera cannot prevent the combustible gas from entering the body, the electronic components of the ordinary camera are working normally. , It is possible to produce sparks, arcs, and dangerous temperatures, so that the combustible gas entering the casing is encountered. In this way, the installed camera not only fails to secure the original intention, but also becomes a “time bomb”.

The real explosion-proof camera manufacturing principle is nothing more than to make the above three conditions different, and it really plays the role of explosion-proof. The earliest explosion-proof cameras are based on the "intrinsically safe" explosion-proof type.

"Intrinsically safe" starts from limiting the energy in the circuit. Inside the camera, the potential spark energy is reduced to the ignitable prescribed gas mixture energy through reliable control circuit parameters, and the wire and component surface heating temperature is limited to the specified gas mixture. The lighting temperature. All circuits inside the camera are intrinsically safe circuits that do not ignite a prescribed explosive gas atmosphere by any spark or any thermal effect produced under standard conditions (including normal operation and specified fault conditions). "Cameras" are relatively expensive and are rarely seen on the market.

Of course, there has also been a "positive pressure type" explosion-proof type in which continuous air or inert gas is maintained in the camera to restrict the flammable mixture from entering the camera through the housing. As for the cameras with “anti-oil type” and “sand-filled” explosion-proof type cameras, there have also been security markets, but the number is very small.

The most common type of explosion-proof camera on the market today is a “flameproof type” explosion-proof type, which completely encloses the parts of the camera that could ignite the explosive gas mixture in a single enclosure whose outer shell can withstand any joint or structural gap through the enclosure. The flammable mixture that penetrates into the interior of the enclosure explodes internally without damage, and does not cause ignition of an external explosive atmosphere formed by one or more gases or vapours. Place parts of the camera that may generate sparks, arcs, and dangerous temperatures into a flameproof enclosure that isolates the interior of the camera from the surrounding environment. There is a gap in the flameproof enclosure. Due to the respiration and gas permeation of the electrical equipment, an explosive gas mixture may exist inside. When the explosion occurs, the enclosure can withstand the explosion pressure generated without damage, and at the same time, the gap of the shell structure can cool the flame and reduce the flame. The speed of flame propagation or termination of the acceleration chain prevents flames or dangerous flame products from igniting the external explosive atmosphere through the flameproof gap, thereby achieving the goal of flameproofing. Therefore, many of these flameproof enclosures are the main security companies.

Therefore, explosion-proof cameras are used in very dangerous places. Our country is very clear on the definition of hazardous areas in the definition of explosion-proof grades, which means that it is caused by the presence of flammable and explosive gases, vapors, liquids, flammable dust, or flammable fibers. Or where the explosion is dangerous. Typical hazardous locations, such as the environment formed during the production, processing, and storage of explosive substances in the petrochemical industry, underground coal mines (working environment due to continuous infiltration of methane gas in coal seams), and so on.

Second, know the riot camera 1, riot camera origin riot camera can not be considered a new species, it is just ordinary camera in special occasions engineering applications, in order to more reasonably function, but in the camera material on the upgrade version, and Can be called a high security camera, impact camera, anti-blow camera, vandal-proof camera.

As the criminal tactics become progressively more rigorous, criminals will pay special attention to destroying surveillance equipment that records images on the scene. They will generally use violence to destroy the security monitoring system. They may use tools such as rocks, iron pipes, rebars, or even pistols. This is exactly what ordinary cameras can't do, so a new category of riot cameras is introduced in the camera category. Many security companies are trying to change the camera's raw materials and process structure, and whether the riot cameras can withstand such violence is the primary consideration when choosing a riot camera.

At present, our country does not have a professional anti-riot rating for cameras. Some insiders divide the existing anti-riot cameras into three levels of general damage prevention, high-intensity destruction and bullet-proof. If you can really use the international standards for testing impact resistance, and use a fire axe and fire axe to make multiple impacts, then the anti-riot rating of a riot camera will be more persuasive in the market.

2. The anti-riot camera's process riot camera is mostly hemispherical or spherical. Therefore, the camera's transparent protective cover and shell's raw material technology directly affect the strength of the camera's anti-riot capability. The common raw material for the riot transparent cover on the market is polycarbonate (PC) engineering plastics, and some of them are polymethyl methacrylate (PMMA) engineering plastics (also known as acrylic, acrylic). Polycarbonate (PC) transparency, light transmission performance, and impact resistance are slightly inferior to polymethyl methacrylate (PMMA). The advantage is that it is inexpensive. However, some manufacturers increase the polycarbonate (PC) thickness in order to increase the impact resistance of the dome cover, which makes the transparency of the dome cover worse. Sanchen DM-818's riot hemisphere is made of acrylic material in order to ensure the amount of light and impact resistance.

Of course, the dome cover material is only one of the aspects of the riot camera. A good riot camera should also include its sturdy and anti-demolition function. The DM-818 base and shell are made of cast aluminum and hexagon nuts. The commonly used screwdriver can be disassembled. In addition, the Sanchen DM-818 riot camera uses an anti-vibration structure inside the camera. A spring structure is adopted at the camera lens, and the external impact is buffered by the resilience of the lens to better play the anti-riot effect of the camera.

3. The application of riot cameras The riot camera is a camera that can still ensure the normal operation of components under the attack of external violence. Its characteristic is that its outer shell has strong impact resistance. On this occasion, there are places where violent emergencies, unattended environments, complicated personnel, and large people flow are commonplace. Of course, there are places where frequent encounters with typhoon, hail and other natural phenomena will cause damage to the camera. .

In recent years, criminal activities around bank robbery and theft have been relatively rampant. Therefore, the application in the financial field has become the main stage for riot cameras to use their feet. The security measures in the financial sector, especially the banks, are mandatory, and CCTV monitoring systems are not to mention. However, in recent years, there have been many criminal activities around the banks in the society. In the financial sector, there has been a demand for riot surveillance products. And there are many applications that are unattended ATM bank ATMs. Because the teller is unguarded, it is the criminal's choice of crime, and the use of anti-riot cameras can better prevent the possibility of being destroyed to ensure that the situation on the scene is recorded.

Some time ago, in the socially popular “hide and seek” incident, its spokesperson said that the camera was damaged in the earlier period, and the monitoring system of the detention center could not play a role. Although many netizens questioned this, I think it is still possible. If the guards are equipped with ordinary cameras instead of riot cameras, the possibility of destruction is still very high. Therefore, the judicial departments of prisons and detention centers are also important applications. According to reports, prisons need to deal with emergencies at any time, and the security of this special environment is also different from other sites, including the suppression of some violent incidents in prisons, and also the resistance from malicious attacks. To say that general monitoring equipment is incompetent, it must have the capability to work normally in the event of violent destruction.

The application of riot cameras is not limited to ATM teller machines and prison guards. For example, public security bureaus, courts, stations, subways, 24-hour convenience stores, etc., are all likely to be the targets of malicious attacks by criminals. In fact, riot cameras should be used.

4. The future of riot cameras As people's safety awareness gradually increases, the field of riot camera applications should theoretically become wider and wider, but in fact, according to my understanding of the security market, the amount of riot cameras is not very large. My analysis has these three factors.

The first important factor is the cost factor. The price of a riot camera is more than 30% higher than that of an ordinary camera with the same parameters. Domestic engineering companies and users do not have a high degree of acceptance of these high-priced products. They still need time to cultivate and change their consumption concepts and consciousness, which also greatly limits the popularity of riot cameras.

The second factor is that everyone does not have enough awareness of the need for "riot protection." We all know that in order to have a wider surveillance range, the camera is usually installed at a higher position. Therefore, the possibility of being destroyed by criminals is also relatively small. If you are standing on the ground and throwing a camera with stones, it is less likely to hit. And in public places, criminals are not so bold that they use sticks or ladders to dismantle. This also led to the selection of ordinary cameras in such places where “anti-riot” requirements are not so prominent, due to cost and cost factors. We often hear people in the industry say: “The conch shell of a metal shell is not riot-proof except for the glass, and other parts are riot-proof.” So many times, ordinary cameras replace a considerable part of the area where riot cameras are used.

The third factor is that surrounding facilities are not "riot-proof". No matter how good a riot camera is, if it is not equipped with anti-riot back-end equipment or professional construction, it will not have the effect of riot protection. For example, it is not an anti-riot cloud platform, or the transmission line is exposed, and the camera power supply is unstable. Equipped with a riot camera capable of preventing bullets, it is still unable to maximize the effectiveness of riot control.

5, the price of explosion-proof camera is about more than 50,000. 6, explosion-proof camera manufacturers have foreign countries, the United States, Germany, Italy, but the prices are more than 100,000, domestic, such as Beijing Huajing Shuntong Technology Co., Ltd.