Problems encountered with atmospheric pressure equipment
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This post was last edited by wx_Catherine_Mi on 2019-9-15 23:23. I need to design a storage tank at atmospheric pressure, with an inner diameter of 4000 mm and a height of 4000 mm; the top part of the tank is conical with a slope of 7°. The fluid inside has a specific gravity of 1, is non-toxic and non-corrosive, but it does have some viscosity. Steam needs to be circulated inside the tank via coils. I have chosen a wall thickness of 10 mm for the sides, 12 mm for the bottom, and 8 mm for the top. Angle steel reinforcement bars will be used at the top inside the tank, as well as a ring of angle steel around the outside of the tank walls; all of these components are 100*100*10 in size. Due to my lack of experience, I’m currently facing many detailed problems: 1. Are PN10 and PN16 suitable for the connections of this atmospheric-pressure equipment? How should the wall thickness for takeover be calculated? Is a reinforcement ring needed for takeover? How to determine the size of the reinforcement ring (those selected for 50341 are all quite large)? 2. How many angle steel reinforcement bars should be used at the top? How to set it up? Is full welding or spot welding required? Does it need to be welded firmly to the tank wall? 3. Does wind load need to be considered? 4. Is this equipment welded on-site or lifted into place? 5. Is it necessary to set up a ladder? 6. How is the cone tip shaped, from a single steel plate or by welding? 7. To be continued. Please, experts, teach this novice – thanks in advance!
How should one understand your “atmospheric pressure storage tank”? Is it for storing gas or liquid? What is the unit for 4000? “*\"Thickness\" is in millimeters, right? ,,,, There are many questions; it seems the design team will have to handle them. When asking a question, it is necessary to clarify one’s own question clearly; one must specify the volume specifications of the storage tank along with the units used, and also indicate what substance is contained within the tank. This involves considering the pressure and static pressure of the substance, its temperature, as well as whether it is corrosive. In addition, factors such as wind load resistance, foundation design, and anti-corrosion coatings must also be taken into account. It’s not as simple as just saying it – welding steel plates that are 10mm to 12mm thick isn’t something anyone can do, and there’s also the design of the reinforcement parts involved. It is recommended to take a look at the construction plans or samples of related styles, and it’s best to find a designer. The cost, including materials and construction expenses, is calculated by designers and architects after making the designs. You are oversimplifying the problem. Oh, and there are also safety-related construction issues,,,,.
It is recommended to choose a length-to-diameter ratio of 3600 with a height of 4500; this way, the top can be made flat, and no reinforcement ribs are needed inside. Reinforcement ribs should be added on the upper and lower sides outside. It is suggested to install a ring of channel steel with dimensions [10 or [12 around the outside of the tank body – the channel steel can simply be bent into place. For atmospheric pressure containers, you can calculate the height of the hydrostatic column at the bottom and choose PN10 as appropriate. However, I’ve heard that PN16 is more commonly used as it’s easier to obtain, so PN16 is usually chosen for atmospheric pressure applications. For media with a high density, reinforcement is necessary if the pipe diameter exceeds 100; for water, reinforcement is required when the diameter is 150. Twenty-four evenly distributed reinforcement ribs on the top are sufficient. As for the circumferential reinforcement ribs, i.e., the channel steel straps, the design requirement is intermittent welding, with the total length of the welds being no less than half of the circumference. I’ve seen designs where the upper part is fully welded while the lower part is welded intermittently. Wind load must also be taken into consideration. As for whether welding will be done on-site or by lifting, it depends on how the container will be transported. With a length-to-diameter ratio of 4 meters by 4 meters, manufacturing the container as a single unit will present transportation difficulties – many vehicles have a height limit of 4.5 meters, and even low-height trucks are usually at least 1 meter tall. In either case, the height will exceed the 4.5-meter limit, so it is recommended to use a diameter of 3.6 meters, which makes transportation easier. Nevertheless, there’s still a risk of hitting the height limit, so it’s best to manufacture the container in two halves and assemble them on-site, or to prefabricate everything and weld it on-site. A ladder is definitely necessary, one with a cage for accessing the inside of the container – you can find specifications for this in design manuals. There’s also a guardrail around the top of the tank body. The design and cutting of the cylindrical shape are complicated, as it involves piecing together various sections. Check the width and length of the steel plates and let me know the results. Generally, the dimensions are 1 meter by 2 meters, 1.2 meters by 2.4 meters, or 1.2 meters by 6 meters.
Thank you for your critical feedback; I will be more careful when posting next time. I’ll make some changes in a bit
I’m deeply touched to see such a long reply. But aren’t the device’s diameter and height, as well as whether the top is conical or flat, determined by the manufacturing process?
The manufacturing process should take transportation and production into account
Flat roofs have low manufacturing costs and are easy to weld
If the diameter is relatively large, you need to consider whether to carry out processing on site, as that will increase the costs; setting up scaffolding and using cranes on site also incurs expenses. If the diameter is smaller, it’s easier to transport it – it can be manufactured directly and then transported for lifting.
Those involved in engineering and design know that without specifying the unit, it can be either millimeters or meters; not indicating the unit is completely fine, as it does not affect communication or even the construction process. I have designed many such atmospheric pressure tanks for my manufacturing processes; they don’t require any special procedures, seem to work fine in most cases, and I’ve never seen any of them fail.
Thanks for sharing; it seems I need to take another close look at the standards
This is also a problem; I will discuss it with the manufacturing team. Thank you for your reply; it’s been very helpful