Double-screw compost turning machine
The double screws compost turner is a high-efficiency aerobic fermentation equipment with two parallel and symmetrical helical turning shafts as its core working components. It is a key piece of equipment in the fields of large-scale organic fertilizer production, livestock and poultry manure treatment, and municipal sludge resource utilization. The equipment relies on the core technology of "double helix rotation + track walking + deep turning and throwing". Through the strong turning and throwing force generated by the synchronous rotation of the two axes in opposite directions, the material at the bottom of the fermentation tank is turned to the top. At the same time, it realizes lateral and longitudinal movement, so that the material can fully contact the oxygen in the air, thereby completing the entire process of aerobic fermentation and turning and cooling.
Designed with a focus on "great depth, wide span, and high efficiency," the twin-screw turner is tailored for large and medium-sized fermentation facilities. It overcomes the width and depth limitations of traditional trough-type turners, achieving an effective turning depth of 1.5–2.1 meters and a span of 6–11 meters, thereby significantly enhancing the space utilization of fermentation tanks. Through the use of two intermeshing, counter-rotating screw blades, the machine transfers bottom-layer material to the surface and top-layer material to the bottom, while simultaneously breaking up and uniformly mixing the material. Compared to traditional self-propelled compost turners, the double screws compost turner has significant advantages such as a large turning span, low energy consumption, and a high degree of automation. It is widely applicable to scenarios such as manure fermentation at livestock farms, raw material fermentation at fertilizer plants, the processing of residues from distilleries, food processing plants, and sugar refineries, as well as the fermentation of shredded waste. The emergence of the double screws compost turner marks a leap from "shallow turning" to "deep and efficient fermentation" in the aerobic fermentation of organic fertilizer, and it is the core equipment for large-scale organic fertilizer production.
Overall Structure and Core Components
The double screws turner features a modular integrated design and consists primarily of the following seven systems:
(I) double screws Turning Unit: This is the core working component, comprising two parallel, symmetrically arranged screw shafts. High-strength, wear-resistant turning blades—made of specially heat-treated high-manganese steel—are distributed in a staggered pattern along the shafts. The screw shafts utilize a variable-pitch design: a smaller pitch at the feed end increases pushing density, while a larger pitch at the discharge end facilitates material output and prevents clogging. The two shafts rotate in opposite directions at the same speed, generating powerful bidirectional turning forces that pull, knead, and break up organic material within the trough from all angles, ensuring 360-degree turning with no dead zones.
(II) Travel System: Comprising the main travel beam and left/right travel assemblies. The upper part of the main beam interfaces slidably with the travel assemblies, while the lower ends of the main beam are rigidly connected to the travel carriage. Typically utilizing an electric single- or double-girder rail-mounted design, the system employs drive units to power the rotation of the travel wheels.
(III) Lifting and Adjustment Device: Comprising hydraulic cylinders, mounting brackets, and connecting blocks. One end of each hydraulic cylinder is fixed to the travel assembly, while the other connects to the screw shaft assembly. The hydraulic system precisely controls the penetration depth of the screw shafts; the turning depth is accurately adjustable, typically ranging from 1.5 to 2.1 meters.
(IV) Power Transmission System: Comprising the main motor, gearbox, and chain or gear transmission mechanisms. The motor connects to the screw shaft assembly via its output shaft. Equipped with an overload protection device, the system automatically cuts off power if the screw auger encounters large, hard objects or material overload, preventing equipment damage. Some high-end models feature variable-frequency drives (VFDs) to flexibly adjust turning and travel speeds based on material moisture content and depth.
(V) Frame and Lateral Traverse Device: Comprising the main beam, truss structure, and lateral traverse mechanism. The traverse mechanism includes two guide rails, two end beams, and gearboxes mounted on each end beam. The frame utilizes a modular welded structure, offering high strength and excellent stability. (VI) Intelligent Control System: Equipped with a PLC-based control cabinet, it supports switching between manual and automatic modes and features automatic fault diagnosis. Some models can also be equipped with a remote control unit.
Applicable Fields and Industry Coverage
The double screws windrow turner has a wide range of applications.
Organic fertilizer production: Suitable for large-scale aerobic fermentation of livestock and poultry manure (chicken, pig, cattle, sheep, etc.).
Environmental protection: Capable of processing organic solid waste such as municipal sludge and kitchen waste. Agricultural waste treatment: Suitable for crop stalks, rice husks, and similar materials.
Industrial organic waste treatment: Capable of processing sugar mill filter mud, distillery grains, pharmaceutical residues, etc.
Other fields: Widely used in compound fertilizer plants, horticultural nurseries, and button mushroom cultivation facilities for fermentation, decomposition, and moisture reduction processes.
Types of usable raw materials
The double screw windrow turner is capable of processing a wide variety of raw materials.
Livestock and poultry manure: Chicken, pig, cattle, and sheep manure, as well as other related farming wastes.
Agricultural waste: Crop stalks, rice husks, sawdust, etc.
Industrial organic waste: Sugar mill filter mud, distillers' grains, pharmaceutical residues, cassava residue, etc.
Municipal waste: Municipal sludge, kitchen waste, etc.
Other organic materials: Spent mushroom substrate, oilseed cake/meal, etc.
This equipment is particularly well-suited for the composting of materials with low organic matter content, such as sludge and municipal waste; because the organic matter content is low, greater composting depth is required to raise the fermentation temperature and thereby shorten the composting time.
Operating principle and working mechanism
The working principle of the double screws windrow turner relies on the synergistic action of counter-rotating twin screws, rail-based travel, and deep-turning capabilities. Its operation comprises three core stages:
Screw-based Turning Stage:Driven by motors, two parallel, symmetrically arranged screw shafts rotate synchronously in opposite directions. Wear-resistant turning blades, distributed in a staggered pattern along the shafts, penetrate the material layer and lift material from the bottom of the fermentation trench to the top. As the shafts counter-rotate, they exert opposing thrust and shear forces on the material, causing it to tumble vertically and circulate laterally.
Pulverization and Mixing Stage:The powerful action of the twin screws pulls, kneads, and breaks apart the material in all directions, ensuring uniform mixing. The blades feature a flow-optimizing design that compresses material in the center while guiding it outward at the sides, with a throw distance controlled between 1.5 and 2.2 meters.
Relocation and Oxygenation Stage:The machine moves both laterally and longitudinally while turning the material, facilitating full contact between the material and atmospheric oxygen to support aerobic microbial activity. During the turning process, material aggregates are exposed to air, allowing fresh air to permeate the pile and fueling the aerobic microbes that generate fermentation heat. As the pile temperature rises, the influx of fresh air helps lower the temperature, creating a beneficial cycle of heat exchange.
Core Advantages and Performance Highlights
The double screws turner offers several outstanding advantages: Deep turning capability—effective turning depth reaches 1.5–2.1 meters, overcoming the shallow depth limitations of traditional trough-type turners. Wide span—effective turning span reaches 6–11 meters, significantly improving space utilization within fermentation troughs. Uniform turning with no dead zones—counter-rotating twin screws ensure 360-degree coverage, achieving fermentation uniformity of over 92%. Powerful performance—easily breaks down high-moisture and clumped materials. Energy efficiency—the synergistic twin-screw design drastically reduces energy consumption. Smart and convenient—features PLC intelligent control, allowing the entire process to be managed by a single operator. Durability and reliability—core components are constructed from high-manganese steel. Shortened fermentation cycle—reduces the traditional 60–90 day composting period to just 15–25 days.
| 型号 Model |
主电机 Main Motor |
小车行走电机 Small Car Moving Motor |
大车行走电机 Big Car Moving Motor |
液压泵电机 Hydraulic Pump Motor |
| SLP-10m | 15KW | 1.5KWX2 | 1.5KWX2(4) | 4KW |
| SLP-12m | ||||
| SLP-15m | ||||
| SLP-20m |
