The pressure in the exhaust gas is around 2-5 Kpa. What pressure value is appropriate for selecting butterfly valves and other piping components in this case?
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The pressure in the exhaust gas is around 2-5 Kpa. What pressure value is appropriate for selecting butterfly valves and other piping components in this case? PN10? Is the pressure too high? Are there any standards for duct valves?
The pressure at high breathing rates can reach over a thousand pascals, so it’s no problem to use a PN10 butterfly valve. Here, PN10 refers to the pressure that the butterfly valve can withstand, and it does not mean the pressure that the butterfly valve will exert on the medium inside. Valve standards can be found on the Gongbiao website under GBT12220~12251; there are many standards in this series. If one only needs to select valves, a valve manual available online is sufficient.
But with an actual wind pressure of around 5 kPa, if the valve is PN10, which has a capacity of 10 kg, wouldn’t that be quite wasteful?
The minimum pressure rating for valves can be PN2.5, but generally they start at PN10 or higher. You can check the valve manual; the valve body may be a bit thinner, but the overall diameter remains the same, and the prices of these valves don’t differ much. Valves with a pressure rating of PN10 or higher are the most commonly used and are easy to find. It is essential to purchase those with a PN2.5 rating, as they are not readily available, which could lead to problems in terms of supply and maintenance later on. Designing is not running a business; there’s no need to consider such costs.
There are specialized ventilation butterfly valves; the pressure should be set at 0.1C, and the corresponding pressure rating is 0.01 MPa! Ventilation butterfly valves generally have a low pressure rating, so there’s no need to choose PN2.5 or PN10! Some are in the valve samples
Valves are standard components; simply select them according to the manual, as they are suitable for your pressure and temperature conditions
It’s difficult to determine the characteristics of exhaust gas alone – what is its toxicity, its level of hazard, and whether it is flammable or explosive? Should purging be performed? What are the temperature and pressure of the purging medium? If the above applies, it is essential to select the valve according to the 10kgf standard. If none of these apply, and it’s even possible to connect it to the atmosphere, then choosing 2.5 kgf is also fine.