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.

Structural Composition

The entire equipment adopts a modular design, mainly composed of the following five parts:

1. Raw Material Storage Bin Group

Number of bins: Standard configuration 3-8, can be customized to more than 10 bins depending on the complexity of the formula.

Single bin volume: Typically 1-3 m³, bin bodies are made of carbon steel or stainless steel (304/316L).

Auxiliary devices: Pneumatic arch breakers or vibrators are installed on the bin walls to prevent powdery and wet materials from bridging and clumping; dust collection ports are installed on the bin tops to connect to the workshop dust collection system.

2. Feeding Mechanism

Each bin is equipped with an independent feeding device, selected according to the material characteristics:

1)Belt feeder: Suitable for dry granules with good flowability (such as urea, potassium chloride);

2)Screw feeder (auger): Suitable for powdery and small granular materials, the feeding speed can be precisely controlled by frequency conversion speed regulation;

3)Vibrating feeder: Suitable for organic fertilizer raw materials that are prone to sticking to the walls and have high moisture content.

3. Single Weighing Unit

Weighing Hopper: Located centrally below all hoppers, suspended installation, capacity 500–1500 kg/batch.

Weighing Sensors: Equipped with high-precision resistance strain gauge sensors (typically 3–4), accuracy class C3, batching error controlled within ±0.1%–±0.3%.

Discharge Gate: Pneumatic butterfly valve or flap valve at the bottom of the weighing hopper, automatically opens for discharge after weighing reaches the target.

4. Mixing and Conveying System

Mixing Silo/Buffer Hopper: Receives weighed materials for brief premixing;

Belt Conveyor: Transports the batched materials to the next process (mixer, granulator, or packaging machine).

5. Control System

PLC + Touch Screen/Industrial Computer: Enables formula management, automatic sequential control, real-time weight display, and fault alarms.

Software Functions: Supports storage of dozens to hundreds of formulas, one-click switching; features automatic drop compensation, out-of-tolerance alarm, data recording, and report output functions.

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.

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.

Common Faults, Causes, and Standardized Solutions

Target Audience and Selection Recommendations

1. Main Target Audience

Small and medium-sized organic fertilizer plants: Annual production of 10,000-50,000 tons, with diverse raw materials and frequent formula changes, prioritizing cost-effectiveness;

Compound fertilizer/BB fertilizer manufacturers: Require precise control of NPK ratios to meet national nutrient content standards;

Feed processing plants: Precise formulation of multiple raw materials (corn, soybean meal, premix, additives);

Blended fertilizer (BB fertilizer) distributors: Flexible formulation of different contents based on orders, multi-variety small-batch production;

Start-up fertilizer companies: Limited budget, hoping for a single set of equipment to handle both organic and compound fertilizer production.

2. Core Selection Principles

Select the number of compartments based on formula complexity: 4 compartments for conventional formulas with 3-4 raw materials; 6-8 compartments for complex formulas (including trace elements and microbial agents).

Select the feeding method based on material characteristics: Belt feed for granular feed; variable frequency screw feed + arch-breaking device for powdery/wet feed.

Select sensors based on accuracy requirements: ±0.3% for ordinary organic fertilizers; ±0.1% for compound/BB fertilizers, with automatic drop compensation.

Select models based on production capacity: PLZ1000 for 10,000–30,000 tons/year; PLZ1200 for 30,000–50,000 tons/year; PLZ1500 or dual systems in parallel for over 50,000 tons/year.

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.