Barite and bentonite arrive at a mud plant by the hundreds of tonnes, and they have to be stored, moved and measured without filling the air with dust or losing track of how much went into the mud. That is the job of the bulk silo system: a set of pressure silos, a conveying network, dust control, and a weighing stage that together turn a truckload of dry powder into a measured, on-spec addition to a batch. This page walks the system from the silo to the weigh hopper.
The silo and its aerated cone
Dry bulk is stored in vertical pressure silos. Barite and bentonite are dense, cohesive powders that will bridge and rat-hole if simply left to gravity, so the cone bottom is aerated — fluidizing air pads or slides loosen the powder so it flows. The silo carries a bin vent on its roof to filter the air displaced during filling, and pressure/vacuum relief to protect the structure, because pneumatic filling both pressurises and, on discharge, can pull a vacuum.
The rotary airlock
Material leaves the cone through a rotary airlock (star valve). Its job is precise: let powder drop into the conveying line without letting conveying pressure escape back up into the silo. The rotor vanes run in the abrasive stream, so they are a wear part — worn vanes leak air and cost conveying performance. The airlock is also the metering point, regulating how fast material enters the line.
Dense-phase conveying
From the airlock the material is conveyed pneumatically to where it is needed. Mud plants favour dense-phase conveying for barite: low velocity, higher pressure, material moving as slugs rather than a fast cloud. The reason is abrasion — dense phase moves the same tonnes at a fraction of the velocity, so the line and its long-radius bends last far longer than they would in high-velocity dilute phase.
Dust control — bin-vent and baghouse
Every transfer point makes dust, and a serious plant captures all of it. The bin vent on the silo and the filter-receiver at the destination separate conveying air from material locally, while a pulse-jet baghouse handles the larger dust load: dust-laden air is drawn in, fines build on the bags, clean air discharges through an ID fan and stack, and short bursts of compressed air shake the cake into a hopper for reclaim. The differential-pressure gauge across the bags is the master indicator of dust-system health.
The sender — dense-phase transfer
Where dense-phase transfer is done in batches, a sender (pressure pot) does the work: it fills with material, seals, pressurises with compressed air, and blows its charge along the line as a dense slug. It is the heart of a dense-phase system, moving abrasive powder gently and at low velocity.
The weigh hopper
The conveying network ends at a load-cell weigh hopper. Material drops in until a target mass is reached (gain-in-weight) or is metered out by weight (loss-in-weight), and a weigh controller reads the load cells continuously. This is the step that makes a weight-up repeatable: “add barite until it looks right” misses density, but a measured mass hits it the first time.
Key takeaways
A bulk silo system stores dry barite and bentonite in aerated pressure silos, meters it out through a rotary airlock, and conveys it in low-velocity dense phase through long-radius bends to protect against abrasion. Bin vents, a filter-receiver and a pulse-jet baghouse keep the whole chain dust-free and reclaim the fines, and a load-cell weigh hopper delivers an exact mass to the mud so density is repeatable. Silo sizes, conveying distances and capacities vary by plant; the store-convey-vent-weigh architecture is constant.