How to choose a suitable discharge method for steel silo?
Steel silos are widely used in grain processing, transshipment and other fields because of their high land utilization rate, high degree of automation, short construction cycle, and low investment cost. With the needs of economic development, the obvious trend in the use of steel silos is that the capacity of single silos is getting larger and larger. As the warehouse capacity gradually increases, how to ensure the smooth delivery of materials has become a key consideration in the design and use of steel silos.
There are concrete foundation (concrete hopper) and full steel supports. Advantages of this kind of discharge method: smooth discharging and no residual material; simple process and easy operation without auxiliary equipment; full use of silo volume; and short construction period. Disadvantages: high civil construction cost due to higher silo foundation. The civil construction cost may be higher than a silo cost if the diameter of the steel silo is too large, so this discharge method unsuitable for the silo with a large diameter.
2.Half-hopper combined with backfilling inside silo
Advantages: no residual material in silo after discharging; simple process without ausiliary equipment; silo foundation is lower compared with full-cone self-discharging method. Disadvantages: backfill reduces the active volume of steel silo.
Make several openings at intervals on silo foundation plate (an odd number generally). Advantages: no backfill and full use of silo volume. Disadvantages: material in silo can not be emptied through self flow, so auxiliary equipment is needed. Such as sweep auger, loading truck etc.
4.Fluidized bed discharge
Make a special air duct on backfill slope ( a small angle), and lay a sieve plate on it, then residual material will be discharged out in a semi-suspended state on air duct under airflow. Advantages: there are less residuals in silo by the use of fan; less backfill reduces the loss of silo volume; and the silo has a good ventilation performance because of a large amount of air ducts which are evenly laid. Disadvantages are complex backfill process, difficult construction and unstable material discharging effect.
5.Other discharge methods
There are some uncommon discharge methods, such as side wall discharging and vibration discharging. For example, big bran that has poor liquidity needs to be discharged by vibrating bin discharger.
The choice of discharge method for a steel silo needs to be comprehensively considered from the aspects of the silo specification, discharge process, frequency of use, and economy.