Material of instrument connection flanges in the heating furnace and suitability for temperature and pressure
Thread Content
Many heating furnaces operate at temperatures of 600–1000 degrees, with flue gas and air present, and under conditions of slight negative to slight positive pressure. . Based on these operating conditions, materials for connection flanges used in applications such as thermometers and zirconia components should generally be 316 or a material capable of withstanding higher temperatures, and the pressure rating should be 600LB or higher. However, in actual engineering design, many people only use 316, 300LB, or even 150LB flanges. What is the reason for this? If a short tube about 150–200 mm long is extended out of the furnace in a timely manner, I don’t think the temperature will drop much.
The operating pressure is slightly positive or slightly negative; 300 LB is approximately equal to 14 KPa of pressure, which should be sufficient
I only have some data available for reference; LB150 generally corresponds to PN1.6 or PN2.0 (MPa), while LB300 corresponds to PN2.5, PN3.0, or PN4.0 (MPa). For material 316 at PN2.5, the maximum shock-free pressure at 450° is only 1.57 MPa, and for PN4.0, it’s only 2.47 MPa at 500°. Even if the flue gas temperature is 600°+ and the pressure is in the range of slight negative to slight positive pressure, there should still be enough headroom