Laboratory Centrifuge Nitrogen Explosion-Proof Protection Requirements

Release time:

2012-01-04

Overview:

The Lu Xiangyi centrifuge employs an improved nitrogen protection system. The design incorporates an online oxygen detection device and a pressure transmitter sensor to monitor the oxygen concentration within the centrifuge’s chamber during operation, enabling quantitative control and ensuring that the oxygen content remains within a safe range.

We know that the three factors that can trigger a nitrogen explosion in a centrifuge are temperature, an ignition source, and oxygen. The fundamental theory behind preventing chemical explosions lies in ensuring that these three basic conditions—essential for the occurrence of a chemical explosion—are never simultaneously present. In other words, the essence of all technical measures aimed at preventing chemical explosions involving combustible substances is to prevent the simultaneous occurrence of these three basic conditions.
Among them:
(1) Temperature—For a specific medium, whether in the liquid or gas phase—when designing a process, the operating temperature of the centrifuge should be taken into account. This primarily depends on the process conditions and will not be discussed in detail here.
(2) Fire sources: During centrifuge design, sufficient safety clearance must be provided between moving parts and the rotor pump to eliminate any potential mechanical friction or impact. Additionally, the machine must incorporate measures to dissipate static electricity. As for braking systems, mechanical friction-based brakes are prohibited; instead, electrically powered energy-consuming brakes are typically used (non-contact brakes—though their drawback is that the braking time tends to be slightly longer than that of contact brakes, especially under full-load conditions where the moment of inertia is relatively high). Furthermore, anti-static belts should be selected for drive belts to eliminate or reduce the likelihood of static electricity generation. (3) Oxygen: Generally, inert gas protection is employed by introducing nitrogen into the centrifuge interior to displace the air, thereby maintaining the oxygen concentration within a safe range.

　　Explosion-proof protection measures

　　The nitrogen protection system commonly used in centrifuges today actually involves merely installing a nitrogen inlet pipe and a nitrogen outlet pipe on the machine casing. During operation, nitrogen is simply introduced into the internal cavity of the centrifuge. However, there is no quantitative control over whether the nitrogen concentration can reach a safe level; thus, the reliability of this nitrogen protection method is very poor. In contrast, the Luxiangyi centrifuge employs an improved nitrogen protection system that incorporates an online oxygen detection device and a pressure transmitter sensor. These components continuously monitor the oxygen concentration within the centrifuge’s internal cavity during operation and enable precise, quantitative control, ensuring that the oxygen content remains within a safe range—i.e., keeping the oxygen concentration inside the machine below the explosion limits of flammable and explosive media.

 

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