Sterlco SGBD Series Batch Gravimetric Blenders - Manual (Page 19)

Bulletin Number Chapter 2: Functional Description 19 of 101
Figure 7: Typical Weigh Hopper Assembly
The weigh hopper dump door holds the material until it is dumped into the mixing section.
The cylinder is actuated by a solenoid in the valve stack on the side of the blender.
In looking at the pneumatic circuit, you can see that the air regulator controls the flow of air
to the valve stack. When the weigh hopper discharge cylinder solenoid valve is not
electrically energized, it will provide air pressure to the air cylinder and hold the shaft in an
extended position, holding the dump valve closed.
When the air cylinder is actuated, the air pressure to the dump valve will be removed, causing
it to open.
The air cylinder on the weigh hopper includes a spring return to allow the cylinder to retract
in the absence of air pressure on the cylinder. This will cause the dump valve to open.
Caution! The pneumatic system used on the Slide Gate blender, like all pneumatic
systems, is highly sensitive to oily, dirty, wet or contaminated air. If oil, dirt,
water, or any other air-borne contaminates enter the system, the
components could be damaged and injury to the operator could result. A
proper air supply must be supplied to the blender.
When the safety circuit is disabled, the air pressure to the cylinder will drop off by shutting
off all the air supply to the valve stack with the pilot operated master air valve. This will also
cause the weigh hopper discharge door to open.