Pressure vessel Design - Splay out concern

In summary, the speaker is trying to qualify a pressure vessel to PD5500 code but is facing challenges due to derated allowables and limited space for additional bolts. They have decided to use an end cap and threaded lock ring with stub acme threads, but are concerned about the splay out of the lock ring during pressure testing. The material properties of the body, lock ring, and end cap are also mentioned. The speaker's question is whether the lock ring will splay out during pressure testing and they are open to providing additional information if needed. They also mention a collar attachment at the bottom of the vessel, but it is unclear if it is already pressure rated or if they are designing it as well.
  • #1
krithika
12
0
Dear Members,
The existing design for the pressure vessel is an end cap bolted to the body which is not designed to any pressure vessel code. Currently I'm trying to qualify this pressure vessel to PD5500 code. Due to the derated allowables in the code i couldn't go with the bolted arrangement, In order to qualify the existing design i have to triple the number of bolts for which i don't have space.

Not left with much options i decided to go with end cap and threaded lock ring ( Please see attachement-BLOGS). The threads i use in the lock ring is stub acme. Although the thread length and lock ring tensile area are good for 300bar ejection load(internal pressure) as per my calculation, I'm more concerned about the splay out of the lock ring. I did some basic FEA from which the deflection i got was 0.2mm but the stresses are localised and quite high. I'm not sure if i can go ahead with the testing with this fine safety factor margin.

Temperature is 20 deg C, but I am not overly concerned about this at this stage.

Material
Body - 65 ksi
Lock ring - 80ksi
End cap - 80ksi.
 

Attachments

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  • #2
So, what is your question ?
 
  • #3
My question is will the lock ring splay out during pressure testing? Please let me know if you need any additional info.
 
  • #4
I have no knowledge of this stuff, but I'm still interested in one aspect of the problem. Your drawing makes it appear as if the bottom of the vessel is also attached via a collar rather than being formed-in. If so, is it already pressure rated or are you designing that too?
 

Related to Pressure vessel Design - Splay out concern

1. What is a pressure vessel?

A pressure vessel is a container designed to hold gases or liquids at a pressure that is significantly different from the surrounding atmospheric pressure. They are used in a variety of industries, including oil and gas, chemical processing, and power generation.

2. What is the purpose of a pressure vessel design?

The purpose of a pressure vessel design is to ensure that the vessel can safely withstand the internal and external pressures and stresses it will be subjected to during operation. This includes considering factors such as material selection, thickness, and shape to prevent leaks, deformations, and failures.

3. What is meant by "splay out concern" in pressure vessel design?

Splay out concern refers to the potential for a pressure vessel to deform or bulge outward under high internal pressure. This can happen if the vessel is not designed with enough stiffness or if the material used is not strong enough to withstand the pressure.

4. How is splay out concern addressed in pressure vessel design?

Splay out concern is typically addressed by considering the vessel's geometry, material properties, and operating conditions during the design process. This may involve increasing the thickness of the vessel, changing the shape, or using stronger materials.

5. What are the consequences of not addressing splay out concern in pressure vessel design?

If splay out concern is not properly addressed in pressure vessel design, it can lead to catastrophic failure. This can result in injury or death to workers, damage to equipment and the surrounding environment, and financial losses for the company. It is crucial to consider splay out concern in pressure vessel design to ensure the safety and reliability of the vessel.

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