The shape of the hopper is an important factor which determines the supply capacity of the feeder. The required supply capacity may not be able to be obtained depending on the hopper shape. In designing an ideal hopper economical and essintial to full feeder performance, it is necessary to take the following into account.

1. The rear wall angle α shown in the figure should be 60 degrees or more to ensure smooth flow of material. The front wall angIe β should be 5 degrees smaller than the angle α.
2. The hopper tends to devolop a bridge at the throat indicated by the letter, T, so the part T should meet the following conditions.
   
   ・ 2.5 times the largest massive body if material is not uniform in particle size.
   ・ 4 times the largest massive body if material is relativery uniform in particle size.
3. The gate opening B should be at least 2 times the largest massive body, and increase in direct proportion to the required capacity.
   The standard gate opening rate B is 1.2 to 1.5 times the material layer thickness d, which can be calcuIated by the following equation.
4. The hopper opening rate W should be 2.5 times the largest massive body if material is not uniform in particle size, or 5 times the largest massive body if material is relatively uniform in particle size.