Concrete Silos 77 



outwardly curved sections forming the wall imme- 

 diately adjacent to the silo wall proper being attached 

 to the regular outer form sections. The inner form is 

 released and set by means of a steel wedge similar to 

 those used between the sections of the inner shell 

 proper. 



Provision is made for the forming of doors opening 

 into the chute and for the construction of a steel ladder 

 inside of the chute. Reinforcement for the chute is 

 handled as in the silo wall. 



The elliptical openings which are formed for the 

 doors are 20x30 inches. They are usually spaced 24 

 inches apart, but the number and arrangement of doors 

 are optional with the builders. The elliptical shape 

 has been chosen in order to avoid sharp angles. For the 

 formation of this opening a sheet steel door is set be- 

 tween the shells of the machine as the work progresses. 

 This form moulds a concrete jamb 1 inch in width and 

 1/2 inch in depth from the inner surface of the wall. 

 Owing to the shape and draft of the form the jamb is 

 left in perfect condition for sealing the door. Imme- 

 diately after the machine has passed the opening the 

 door form is removed. 



The door itself is made of heavily galvanized sheet 

 steel, cut to fit snugly into the concrete jamb made by 

 the form, flush with the inner wall and bent to the 

 radius of the silo. On the outside of the door are 

 fastened four malleable clips in which hook bolts en- 

 gage. Across the opening on the outside of the silo 

 wooden bars are placed through which these bolts pass. 

 The desired stress is obtained by malleable tail nuts. 

 In sealing the door a thin gasket of moist clay is 

 smeared around the jamb before the door is set in 

 place. 



