In engineering design, the pressure level of the nozzle flange of the container is usually given by the professional of the process system. The following factors should be considered when selecting the pressure rating of the takeover flange.
1 Design pressure and design temperature of the container;
2 Connection standards of valves directly connected to them, valves, fittings, temperature, pressure and liquid level.
3 The influence of thermal stress of process piping (especially high temperature and heat pipe) on the flange of nozzle.
4 Characteristics of process and operation medium:
For vessels operated in vacuum, the pressure level of nozzle flange should not be less than 0.6 MPa when the vacuum degree is less than 79.980 kPa (600 mmHg), and for vessels operated in vacuum from 9.980 kPa to 101.175 kPa (600-759 mmHg), the pressure level of nozzle flange should not be less than 1.0 MPa.
For explosive or toxic medium, the pressure level of pipe flange should not be less than 1.0 MPa; for toxic medium of high and extreme harm or strong permeability, the pressure level of nozzle flange should not be less than 1.6 MPa.
5 The flange with neck butt welded pipe should be used as far as height, extreme hazardous medium and three types of containers should be adopted.
Source: China Stainless Steel Flanges Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)