Issue of the total cross-sectional area of the heat exchanger tie rods
Thread Content
This post was last edited by qqsbig001 on 2023-2-16 at 11:26. GB/T151-2014 6.8.5.2: The diameter and quantity of tie rods shall be selected according to Tables 6-32 and 6-33. As long as the total cross-sectional area of the tie rods is greater than or equal to that specified in Table 6-33, their diameter and quantity can vary; however, their diameter must not be less than 10 mm, and the number must be at least 4. Taking the heat exchange tube of φ25×2 and the heat exchanger specification DN500 as an example, 4 φ16 tie rods should be selected according to the table. If the diameter of the tie rod is changed to φ10, should the total cross-sectional area of the tie rod be ≥4×π×82, rather than ≥6×π×52 or ≥4×π×62? Should the standard wording be changed to: Ensure that it is greater than or equal to the value specified when selecting according to Tables 6-32 and 6-33....
My understanding is that if 10/12/16 cross-section rods are used, the data from the table can be used directly; in cases where data outside the table is used, it must be ensured that the cross-sectional area is not less than the required area for those rods. By calculating the area of the tie rod, it was found that the larger the diameter, the greater the area. The reason may be that when the number of tie rods is low, the uneven stress distribution among them increases, resulting in greater stress on certain tie rods, which in turn necessitates an increase in the area of those tie rods. If other specifications are chosen, I recommend not going below the maximum area requirement.
Think it through carefully; the standard is fine
The last edit to this post was made by wanlirn on 2023-2-16 at 13:48; it’s sufficient for the total cross-sectional area of the tie rod to meet the requirements specified in Table 6-33
It’s a situation like that. A set of drawings has come in from the design institute; they’re ready to use. The specification is DN500, but according to GB/T151, 4 rods of φ16 should be used; however, they have designed it with 8 rods of φ10. Is that acceptable?
This post was last edited by wanlirn on 2023-2-16 at 15:18
I’ll give up. It’s not possible; I just assumed it without thinking
The same goes for the staff at the design institute – can the area be converted in that way? ;P
I’ve also run into the issue of the tube sheet becoming too thin. I’m not sure if the tie rods can be selected directly from 6-33; regardless, there are recommendations for 6-32