Multiple Silos Single Weigh Type

Equipment Overview

The multi-silo single-weighing batching machine, also known as a multi-silo single-weighing static automatic batching system, is an automated batching device that stores multiple raw materials separately in independent silos, weighs them sequentially through a single weighing unit, and then mixes and outputs the mixture. This system typically has 3-8 raw material silos and is suitable for precise batching of multiple materials in industries such as organic fertilizer, compound fertilizer (NPK), BB fertilizer, and feed. Its core feature is “one machine for all”—it can process both granular compound fertilizer raw materials and powdered and wet organic fertilizer raw materials. It offers high batching accuracy, flexible formula switching, and moderate investment costs, making it a core front-end equipment for small and medium-sized fertilizer production lines.

Equipment Structure

The entire machine consists of six main modules: multiple raw material silos, independent feeding mechanisms, a single weighing assembly, a centralized conveying system, a centralized dust removal system, and a PLC electrical control system.

1. Multiple Independent Raw Material Silos: 3-12 carbon steel/stainless steel storage silos, each with an independent conical hopper for feeding. The silo walls are equipped with vibrating anti-bridging motors to prevent fertilizer from absorbing moisture and forming bridging. A unified feed inlet at the top of each silo connects to a bucket elevator; silos are not interconnected.
2. Dedicated Feeding Mechanisms for Each Silo: Each silo has an independent frequency conversion feeding unit: granules are fed by vibrating feeders, and powders by coarse and fine double-spiral feeders. The PLC controls the start/stop of each silo independently, with fast and slow feeding stages, sequentially feeding materials into a shared weighing hopper below.
3. Single Shared Weighing Assembly (Core): The entire machine uses only one stainless steel weighing hopper + 4 high-precision weighing sensors, with a pneumatic discharge door at the bottom. The entire weighing unit is equipped with shock-absorbing pads, and all raw materials are weighed sequentially and cumulatively.
4. Conveying Equipment: After unloading from the weighing hopper, all the mixed material falls onto the bottom belt/screw conveyor and is then uniformly fed into the horizontal mixer for further mixing.
5. Centralized Dust Collection System: The branch pipes from each bin’s discharge port converge to a single pulse dust collector for unified collection of batching dust, eliminating the need for independent dust collection in each bin.
6. PLC Centralized Control System: A single weighing instrument + touchscreen system stores multiple fertilizer formulas, automatically records the total weight of each batch, and issues over-tolerance alarms. It sequentially controls the discharge from each bin and automatically compensates for inertial errors during material discharge.

Working Principle

The system employs a sequential cumulative static batch batching process, where different raw materials are fed into the same weighing hopper in multiple batches to complete the batching:

1. The system retrieves the target fertilizer formula and starts the first raw material hopper’s vibrating/screw coarse feeding mechanism, allowing the material to fall into a shared weighing hopper;
2. Once 90% of the set weight of the raw material is reached, the system switches to fine feeding for micro-feeding. After reaching the standard weight, this hopper stops;
3. The system automatically switches to the next raw material hopper, repeating the coarse and fine cumulative weighing until all raw materials in the formula have been fed;
4. After all raw materials are weighed, the discharge door at the bottom of the weighing hopper opens simultaneously, and all the mixture falls into the concentrator conveyor and is sent to the mixer;
5. After unloading, the weighing hopper returns to zero, and the system automatically begins the next batch batching cycle;
6. Dust generated during the feeding process is collected through branch pipes and filtered and recovered by a centralized dust collector, with fine powder flowing back into the raw material hopper.

Applicable Raw Materials

Suitable Materials for Stable Batching

1. Granular Fertilizers: Urea, Potassium Sulfate, BB Fertilizer Granules, Well-rotted Organic Granules, Oilseed Cake Powder;
2. Powdered Fertilizers: Humic Acid Powder, Chicken Manure Organic Fertilizer Powder, Monoammonium Phosphate, Bentonite, Microbial Powder;

Unsuitable Materials

Moisture Content > 15%; Strongly Sticky Slurry, Extra-long Wounded Fibers, Extra-large Hard Lumps (Easily Clogs Feeding Screw/Vibrator); High-Requirement Water-Soluble Fertilizers, Slow-Release Fertilizers (Not Recommended if Insufficient Proportioning Accuracy).

Equipment Capacity Range

Note: The batching cycle is 3-6 minutes. The more types of raw materials, the lower the hourly capacity.

Applications in Production Lines

1. Organic Fertilizer Production Line

Located after fermentation and turning, and before granulation/packaging:

Fermented and decomposed material → Multi-bin single-scale batching (adding NPK, microbial agents, and humic acid to adjust nutrients) → Mixing in a mixer → Granulator → Drying and cooling → Screening → Packaging

2. Compound Fertilizer (NPK) Production Line

Located after raw material pretreatment and before granulation:

Urea, phosphate fertilizer, potash fertilizer, filler → Multi-bin single-scale batching → Mixer → Drum granulation/extrusion granulation → Drying → Cooling → Screening → Packaging

3. BB Fertilizer (Blended Fertilizer) Production Line

Located after finished granules are stored and before packaging:

Multiple finished granulated fertilizers → Multi-bin single-scale batching → Short-time mixing in a mixer → Direct packaging

This system is the hub connecting raw material storage and core processing equipment; the batching accuracy directly determines the pass rate of the finished product’s nutrient content.

Standard Operation and Full-Cycle Maintenance

(I) Standard Start-up and Shutdown Procedures

Start-up

1. Inspect all bins for clumping, weighing hoppers for fertilizer buildup, dust collector filters for blockages, and air supply pressure of 0.5~0.7MPa;
2. Start the dust collector and conveying equipment under no-load conditions, and perform zero-point calibration on the touchscreen;
3. Retrieve the production formula, conduct a no-load test run on one entire batch, and officially start feeding after confirming the error meets the standard.

Shutdown

1. Stop the front-end lifting and feeding mechanism, and wait for all material to be emptied from the weighing hopper and each bin’s feeding mechanism;
2. Sequentially shut down the feeding, dust collector, and conveying equipment;
3. Clean the shared weighing hopper and all discharge ports of residual fertilizer to prevent clumping and corrosion of the sensors.

(II) Graded Maintenance Standards

1. Daily: Zero-point calibration of the weighing system for each shift, cleaning of material adhering to the weighing hopper, and checking the vibration/screw operation of each bin;
2. Weekly: Lubrication of the feeding drive bearings, and cleaning of dust accumulation on the surface of the dust collector filter bags;
3. Quarterly: Replacement of gear oil in the reducer, and inspection of the load cell wiring and aging of the vibration damping pads;
4. Annual Overhaul: Disassembly of the weighing assembly, thorough cleaning of all feeding mechanisms, and calibration of the overall metering accuracy.

(III) List of Vulnerable Parts

Load cell, screw blades, vibrating motor, dust collector filter bags, pneumatic unloading door seals, drive V-belts.

Common Faults, Causes, and Standardized Solutions

Target Customers:

1. Small and medium-sized organic fertilizer and BB blended fertilizer processing plants with an annual output of less than 100,000 tons;
2. Township livestock cooperatives and small-scale manure-to-fertilizer workshops with limited factory space and equipment budgets;
3. Fertilizer packaging and transshipment warehouses for simple mixing and processing of multiple raw materials;
4. Fertilizer complete equipment suppliers providing small-scale, low-cost production line solutions;
5. Overseas small-scale organic fertilizer processing plants with budgets for purchasing complete sets of equipment.

Comprehensive Technical Features of the Equipment:

1. Low cost and small footprint: Only one weighing unit is required, significantly reducing equipment and civil engineering investment compared to single-weigher units of the same capacity;
2. Simple overall structure, few vulnerable parts, and low daily maintenance workload;
3. Modular silo design, 3-12 silos can be added or removed as needed, adaptable to various fertilizer raw material formulas;
4. Centralized dust removal system, simple pipeline layout, and controllable dust pollution in the workshop;
5. Obvious shortcomings: Batch-by-batch intermittent batching and cumulative metering result in accumulated errors, low production efficiency with multiple raw materials, and frequent material changes can easily lead to cross-contamination, making it unsuitable for high-precision fertilizer production.