How should a 70-cubic-meter silo be set up?
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I’m seeking help from the experts here. I need to build a silo with a capacity of 70 cubic meters. The initial plans are for a diameter of 3600 mm, a straight section height of 6000 mm, and a conical section height of 3000 mm. The wall thickness will be 8 mm throughout, and the silo will be made of Q-235 steel. Preliminary calculations suggest that the weight of the silo, along with the ladder and guardrails, will be around 7 tons. When the silo is full, the weight of the material is about 32 tons. Since the site requires the height of the silo discharge outlet above the ground to be 2000, a structure supported by 4 columns is planned to be used. I would like to ask everyone whether the wall thickness of the silo is reasonable? Is the strength sufficient for the columns using 159×12 seamless tubes? Also, how is corrosion protection provided on the inner walls of the silos? (I noticed that most silos don’t have manholes.) I’ve never designed silos or anything like that before.
If the material is corroded. It is recommended to use composite panel material for fabrication. The four columns should have sufficient strength; you can refer to spherical tanks with four columns.
Activated carbon powder, non-corrosive
If the equipment is at near-atmospheric pressure and the corrosion margin is not large (for carbon steel, even if the material is non-corrosive, a corrosion margin still needs to be considered; after all, carbon steel can corrode in air, and since the material is in powder form, wear and thinning also occur), this thickness should be sufficient. The design of a silo is similar to that of a pressure-free container, but at the junction between the silo body and the hopper, changes in the condition of the material inside the silo – such as when the material was stationary inside the silo and then the outlet suddenly opens – can result in much higher pressures at this junction compared to when the material is stationary. This area requires careful analysis; reference can be made to the specifications for solid material silos or SH3078. Regarding the issue of the legs, this needs to be determined based on wind and seismic loads; it is recommended to pay attention to the local stresses at the junctions between the legs and the cylinder, as well as the stability of the legs themselves.
To be honest, I’m worried about the legs too. The legs need to be 5M tall, and they seem rather unstable. Would it be feasible to connect the four legs together using angle steel and add support in the middle? Additionally, the tank is 11 meters above the ground, and the vertical ladder can only reach a height of 10 meters; therefore, the ladder has to be divided into sections, which is also a hassle. Checking the strength requirements seems like deciphering ancient script – there are too many formulas. I did a rough calculation, and it turns out that the horizontal seismic force is 10,000 N greater than the vertical seismic force.
This post was last edited by zxhslm on 2017-8-15 09:21. First, in addition to considering corrosion margin, wear margin also needs to be taken into account inside the silo. The wall thickness can be calculated by referring to the examples provided in the appendix of NB/T47003.2. Based on the material parameters provided by the poster, the bulk density does not seem to be very high, so the cylinder can be divided into sections. Secondly, rigid ring-ear type supports can be used, while the legs can be designed by the civil engineering team. If there is no civil engineering specialty, calculations can be carried out by referring to the standards for leg-type supports. Based on personal experience, four 159 legs are not sufficient, as there may also be wind loads and seismic loads. Third, regarding the silo body itself, the junction between the cone and the cylinder is a section that is subject to significant stress; it can be strengthened by adding flat steel or angle steel rings. Fourth, as for internal corrosion prevention, it can be addressed by consulting experienced silo installation manufacturers, taking into account the characteristics of the materials inside.
This post was last edited by wanlirn on 2022-9-30 at 14:42. There’s no need to consider seismic loads for the silo; cost is an issue. For outdoor wind loads, it can be calculated. I didn’t see you mention the angle of repose. Could it be that it’s not being taken into account? If the material can’t be discharged at that time, it will cause serious problems