Lou's Place in Cyberspace
CASTLE VALLEY MILL
THIRD FLOOR SUSPENDED BOLTER
Adjacent to, and perpendicular to the Real Elevators is a small "Bolter" or mechanical cylindrical sieve. Grain was fed into this device at one end and fell onto a hexagonal rotating sieve, usually made of fine screening or silk.
As the grain entered it was tumbled down the rotating sieve which was tilted at a slight angle. Gravity would pull the grain through as it rotated. This is the general operating principal of all rotating "Bolters" or sieve separators.
Finely ground flour particles would fall through the mesh and into a channel, where it was moved away from the apparatus through a horizontal auger channel to the far end, and dropped into a small rectangular vertical chute. The remaining larger particles would pass down and out into a separate diagonal chute. Both the diagonal and vertical chutes passed to the second floor in the southwest corner of the building
The Bolting machine is suspended from the third floor cross tie beams, and is perpendicular to the rear elevators. In this view from the rear of the mill, the white bolting cloth can be seen, as the side cover has been removed. The diagonal chute in the foreground and the small vertical chute from the long auger box, passed to the second floor. The distant diagonal chute is from the Central Rear Elevator tray, not associated with this device. This seems to imply that the southwest corner of the building on the second floor was where the product was stored or bagged.
The bolter was driven by a large pulley mounted on the end nearest the elevators. Power to the Bolter was from a belt drive shaft which also powered the Central Rear Elevator.
Power end of Bolting machine. The smaller center pulley drove the lower auger pulley which turned an auger in the lower trough box. The finer flour moved through the auger towards the far end. Side panel shown removed. There still remains the last used silk bolting cloth on the cylindrical drum when I first viewed the bolter.
I found no manufacturer name on this device, and it appears it was constructed on site. The main drive pulley, made of wood, also appears hand-made. A highly skilled and experienced Miller often had to make or repair equipment to keep the mill producing with no down time.
Flour to this machine came from the Central Rear Elevator, which has a chute spouting directly to the Bolter receiving box, located behind the main pulley.
Bolter with side and rear auger cover removed. Flour passing through the fine mesh fell into the lower auger trough and was moved along to the rear vertical chute. The top diagonal chute fed flour from the Central Elevator
Rear of Small Bolter. Top auger cover removed to show detail. Note teardrop shaped cleanout cover over the diagonal chute. In the foreground is the hexagonal shaft holding the small paddles making up the spiral auger shaft.
Rear of bolter.
Side view of Bolter, looking towards front of Mill from rear. Drive Pulley wheel on left is situated next to the Rear Elevators.
View from opposite side. Note cut-off rear elevator legs on right.
View of receiving box located behind the main drive pulley. Grain was directed into this box from Central Rear Elevator.
Chute (on right) from Central Rear Elevator discharged into the small bolter. Note tear-drop shaped clean out hole covers. Chute at top, left of center, is fed from Rear Elevator #3. It did not connect to Bolter.
Main drive pulley and smaller auger drive pulley below it. A belt would connect both small pulley wheels.
Main drive pulley with smaller central pulley detail.
View of bolting cloth still attached to its hexagonal frame. This is a medium mesh.
View of auger trough showing wooden paddles on hexagonal horizontal shaft. These paddles moved the flour along the channel to the rear vertical chute.
Rear of Bolter. Note teardrop shaped clean out hole cover.
This bolter appears to date from the time the mill was extended, after 1879. It is a small bolter and may have been used for rough ground grain separation for animal feed or preparation for further bolting processes.
Pulley on left drove the large Bolter drive pulley by belt from the rear horizontal drive shaft pulley. Pulley right of center (in shadow) powered the Rear Central Elevator head located above it in the roof peak.
Though the dressing machine at the Mill appears to have been made on site about 1880, this illustration shows all the same principals of operation, from a catalog of milling equipment.