Windrow Compost Turning Machine

Windrow compost turner

The windrow compost turner—also known as a self-propelled turner, crawler-type turner, or mobile turner—is a high-efficiency piece of equipment designed specifically for ground-based, windrow-style aerobic fermentation processes. Featuring a self-propelled design, the machine straddles pre-stacked elongated windrows to perform turning, aeration, and pile-shifting operations; it serves as core fermentation equipment in the fields of organic fertilizer production and organic waste resource recovery.

The design philosophy of the windrow compost turner centers on mobility, flexibility, the elimination of civil engineering requirements, and strong adaptability. Unlike in-vessel or channel-type turners that require the construction of fixed fermentation channels, windrow turners operate directly on materials stacked in long rows on the ground, thereby avoiding the capital investment associated with building channels. The equipment is highly versatile regarding site selection, capable of operating in open-air areas as well as inside workshops or greenhouses.

These machines are primarily available in two configurations: crawler-type and wheeled. Crawler-type turners offer superior maneuverability and traction, providing a distinct advantage when handling high-moisture or viscous materials; they effectively overcome the slippage issues often encountered by wheeled models during operation, making them the mainstream choice for windrow composting. Capable of processing a wide range of organic materials—such as livestock manure, municipal sludge, distillers' grains, pharmaceutical residues, crop straw, furfural residue, and green waste—these turners are widely used in organic fertilizer production, livestock farm waste treatment, municipal sludge resource utilization, and the preparation of edible mushroom substrates.

Overall Structure and Core Components

The windrow compost turner features a modular, integrated design, with the machine primarily composed of the following six major systems:

(1) Turning Mechanism:This is the core working component of the equipment, consisting of a turning drum (rotating blade shaft) and high-strength turning blades (tines) mounted on the drum. The drum typically employs a horizontal spiral configuration, featuring counter-rotating spiral sections on the left and right sides and straight-section tines in the middle. The blades are made of highly wear-resistant alloy materials (such as Cr12MoV high-chromium alloy) and undergo special heat treatment to ensure excellent wear and impact resistance. During operation, the blade shaft penetrates deep into the material pile to perform mixing, crushing, and aeration (fluffing) tasks.

(2) Travel System:This includes either a crawler (tracked) or four-wheel travel mechanism. Crawler-type turners use rubber or metal tracks, allowing for operation on various surfaces such as concrete or compacted soil. The crawler design results in low ground pressure, preventing the machine from sinking into soft ground, whereas the four-wheel design offers a simpler structure. The machine is capable of moving forward, reversing, and turning, and is operated by a single person. Some high-end models utilize hydraulically assisted crawler drives, enabling 180° turns in place, which significantly saves site space.

(3) Hydraulic Lifting System:Composed of a hydraulic pump station, hydraulic cylinders, control valve assemblies, and hydraulic piping. The lifting of the turning drum is controlled by the hydraulic system; the drum's height above the ground can be flexibly adjusted based on the material pile's height and the fermentation stage, allowing for precise control of the turning depth. Some models incorporate a hydraulic balancing device, ensuring automatic four-wheel balance adjustment on uneven terrain and enhancing site adaptability.

(4) Power Transmission System:Typically powered by a diesel engine, with power outputs ranging from 38 kW to 123 hp. The diesel engine's power is split: the primary output drives the turning drum via a pulley-based reduction transmission, while the secondary output drives the hydraulic pump through a power split gearbox to supply the hydraulic system. The drive system utilizes hardened-gear reducers and specialized gearboxes, ensuring reliable performance, low failure rates, and ease of maintenance.

(5) Control System: Includes the operator's cab, control levers, and a hydraulic control valve assembly. Operators control all functions—such as travel, steering, drum lifting/lowering, and drum start/stop—via the hydraulic valve assembly. The system relies entirely on joystick controls, offering flexible and simple operation.

(6) Frame and Safety Protection: The frame is constructed from welded high-strength steel, providing excellent structural rigidity and balanced load distribution. The equipment typically comes with an operator's cab, with optional comfort features such as air conditioning available.

Applicable Fields and Industry Coverage

Windrow compost turners have a wide range of applications.

Organic fertilizer production: Suitable for the aerobic windrow composting of livestock and poultry manure (chicken, pig, cattle, sheep manure, etc.).

Environmental protection: Suitable for treating organic solid waste such as municipal sludge and kitchen waste.

Agricultural waste treatment: Suitable for composting crop straw and garden waste.

Industrial organic waste treatment: Suitable for materials such as distillers' grains, pharmaceutical residues, cassava residue, and furfural residue.

Other fields: Widely used in the preparation of edible mushroom substrates, fermentation of horticultural substrates, etc.

Types of usable raw materials

Windrow compost turners can process a wide variety of raw materials.

Livestock and poultry manure: Chicken, pig, cattle, and sheep manure, as well as other animal farming wastes.

Municipal waste: Municipal sludge, household waste, kitchen waste, etc.

Agricultural waste: Crop stalks, rice husks, sawdust, garden waste, etc.

Industrial organic waste: Distillers' grains, medicinal residues, cassava residue, furfural residue, fruit peel/pulp residue, etc.

Operating Principles and Working Mechanisms

The working principle of the windrow compost turner is based on the aerobic fermentation concept of "mechanical turning combined with natural oxygen supply." Its operation involves three core stages:

Straddling and Positioning: The machine straddles a pre-formed elongated compost pile (windrow) and is operated by a single driver. The width of the windrow is determined by the turner's operating span and generally should not exceed its rated turning width.

Turning and Pulverizing: A diesel engine drives the turning drum to rotate at high speed; blades on the drum cut into the material pile, turning, aerating, pulverizing, and displacing the material. The rotating spiral drum gathers the triangular windrow material toward the center while simultaneously throwing it backward.

Oxygenation and Re-piling: During the turning process, the material is lifted by the high-speed drum and propelled backward; as it falls and resettles, heat and mass exchange occurs with the surrounding air. Moisture and carbon dioxide are released, the temperature drops, and oxygen levels rise, creating an optimal environment for aerobic microbial fermentation. After the machine passes, the material is reformed into a new windrow.

Core Advantages and Performance Highlights
Windrow compost turners offer the following distinct advantages: No civil engineering required—eliminates the need to construct fermentation pits, saving on infrastructure investment. High mobility—operates effectively in open-air areas or inside workshops and greenhouses, offering strong site adaptability. Agile turning—capable of making 180° turns on the spot, saving space. Single-operator control—easily operated by one person. High processing capacity—typical models process 400–700 cubic meters per hour. Wide range of applications—suitable for processing various types of organic waste. Anti-slip capability—the crawler-track design effectively resolves the slippage issues common with wheeled turners during operation.