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What is the working principle of an explosion-proof valve?
Release time:2019-04-09
The PUW explosion-proof valve uses an imported expanded polytetrafluoroethylene (E-PTFE) microporous membrane as its primary waterproof and breathable material. The micropores in this imported E-PTFE membrane have diameters ranging from 0.1 to 10 μm. By contrast, the average diameter of an air molecule is only 0.00036 μm, while the average diameter of a water vapor molecule is 0.00047 μm. A drizzle droplet, on the other hand, has a diameter of around 500 μm. Thus, the pore size of the E-PTFE membrane is more than 1,000 times larger than the diameter of gas molecules—and thousands of times smaller than that of water droplets. Moreover, due to the extremely low surface energy of the E-PTFE membrane, under the influence of surface tension (where water molecules pull on each other), small water droplets will remain on the surface of the E-PTFE membrane.
The PUW explosion-proof valve uses an imported expanded polytetrafluoroethylene (E-PTFE) microporous membrane as its primary waterproof and breathable material. The micropores in this imported E-PTFE membrane have diameters ranging from 0.1 to 10 μm. By contrast, the average diameter of an air molecule is only 0.00036 μm, while the average diameter of a water vapor molecule is 0.00047 μm. A drizzle droplet, on the other hand, has a diameter of around 500 μm. Thus, the pore size of the E-PTFE membrane is more than 1,000 times larger than the diameter of gas molecules—and thousands of times smaller than that of water droplets. Moreover, due to the extremely low surface energy of the E-PTFE membrane, under the influence of surface tension (where water molecules pull against each other), small water droplets quickly coalesce into larger beads on the membrane’s surface. As a result, gases can pass through smoothly, while liquid water cannot penetrate the membrane, giving it excellent waterproof and breathable performance.
When the internal pressure inside the battery pack enclosure is lower than the burst pressure set for the explosion-proof valve, the system is in its normal operating state (as shown in the right diagram). In this operating state, the valve functions in the same way as a conventional waterproof and breathable valve: Gases inside and outside the cavity freely flow through the E-PTFE waterproof and breathable membrane built into the valve. Gas flows from the side with higher pressure to the side with lower pressure—meaning that when the internal pressure of the cavity exceeds the external pressure, gas is vented outward; conversely, when the internal pressure is lower than the external pressure, gas enters the cavity, thereby achieving pressure equilibrium between the inside and outside. Under these conditions, the PUW explosion-proof valve acts as a waterproof and breathable valve (a breather valve).
When the internal pressure inside the cavity exceeds or equals the burst pressure setting of the explosion-proof valve, the system enters an explosion-proof operating state (as shown in the right diagram). At this point, the internal pressure pushes open the built-in piston, allowing gas to flow directly through an unobstructed passage to the outside, thereby rapidly venting the gas and quickly reducing the internal pressure, thus preventing the cavity from bursting. In this state, the system effectively serves as an explosion-proof device.
When the internal pressure drops below the rupture value set for the explosion-proof valve, the PUW explosion-proof valve will immediately return to its normal operating state. Therefore, the PUW explosion-proof valve is not a disposable product and can be 100% inspected both before shipment and during use to ensure that its explosion-proof function meets the required standards.
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