1000 Liters Sigma Mixer

The 1000 Liter Sigma Mixer, also known as a Sigma Blade Kneader or Z-Blade Mixer, is a robust, heavy-duty industrial machine engineered for the intensive mixing, kneading, and processing of high-viscosity, semi-solid, and elastic-plastic materials. This equipment excels in applications requiring thorough shear, stretching, folding, and homogenization, making it indispensable in industries such as chemicals, pharmaceuticals, food processing, rubber, plastics, adhesives, and cosmetics.

Sigma Mixer Machine Video

Design and Construction

The core of the 1000L Sigma Mixer is a horizontal, W-shaped or U-shaped trough (mixing chamber) constructed from durable materials like mild steel, stainless steel 304, or 316L for corrosion resistance and hygiene compliance. The trough measures approximately 2-3 meters in length and 1-1.5 meters in width, with a depth optimized for optimal material flow. Inside the trough, two counter-rotating Z-shaped (Sigma) blades are mounted horizontally—one typically rotating at a faster speed (e.g., 0-42 RPM) than the other (e.g., 0-35 RPM)—creating tangential shear forces against the trough walls and each other. The blades are precisely machined with minimal clearance (often 2-5 mm) to the walls, ensuring maximum kneading efficiency and preventing material buildup.

Key structural elements include:

• Jacketed Trough: Welded double walls for heating (via steam or hot oil) or cooling (via water or chilled fluids), maintaining precise temperature control up to 200°C for processes like vulcanization or polymerization.

• Drive System: Powered by a high-torque motor (commonly 50 HP or dual motors for larger capacities), coupled with a hydraulic coupling, helical reduction gearbox, gear coupling, and heavy-duty helical gears. Variable frequency drives (VFD) allow speed adjustments for different viscosities.

• Sealing and Safety: Dust-tight or vacuum-rated lids with hydraulic tilting mechanisms for easy charging and discharging. Safety features include interlocked guards, emergency stops, and CE/ISO 9001 certifications.

The mixer’s footprint is compact for its capacity, typically 4-5 meters long, 2-3 meters wide, and 2.5-3 meters tall, mounted on a vibration-dampening steel frame for noise-free operation.

Operational Principle

Material is loaded through a top-opening lid (fully hinged for big-bag access) or side ports. The Sigma blades rotate in opposite directions, generating intense shear, compression, and recombination forces that propel the batch through bulk movement, stretching, folding, dividing, and recombining actions. This simulates manual kneading on a massive scale, achieving homogeneity in 10-30 minutes per batch. The slower blade handles bulk transport, while the faster one provides aggressive dispersion.

Discharge options include:

• Hydraulic Tilting: The trough tilts up to 120° for gravity unloading into downstream equipment.

• Screw Extrusion: An integrated bottom screw conveyor (hydraulically driven) forces viscous material out through a side or bottom port, ideal for sticky pastes like adhesives or dough.

• Manual or Pneumatic Valves: For free-flowing batches.

Applications

This mixer is versatile for processing:

• Chemicals & Adhesives: High-density sealants, hot melts, silicone rubber, butyl rubber, inks, pigments, and carbon pastes.

• Pharmaceuticals & Cosmetics: Ointments, creams, gels, and polymer bases requiring sterile, uniform blending.

• Food & Confectionery: Dough, chewing gum, bubble gum, chocolate syrups, and thick batters (food-grade models ensure GMP compliance).

• Rubber & Plastics: Vulcanization of elastomers, BMC (bulk molding compounds), and plasticine.

• Other: Explosive binders (with safety adaptations), batteries, clay, and pulp.

In explosive manufacturing, for instance, it provides the shear needed for stable, homogeneous formulations of viscous binders.

Advantages and Considerations

The 1000L Sigma Mixer stands out for its reliability in handling viscosities up to 10 million cps, outperforming planetary or ribbon mixers for sticky materials. It reduces labor, ensures batch-to-batch consistency, and scales easily for production lines. Maintenance is low, with modular components for quick servicing.

Salient Features of Sigma Mixer Machine

• Available in Stainless Steel 316, Stainless Steel 304 and Mild Steel materials.

• Stainless Steel polish to matt & mirror finish as per customer’s requirements.

• Mild Steel finish with one coat of red oxide and two coats of epoxy paint.

• Discharge option of hand wheel operated (manual) or hydraulic operated (automatic) offered.

• Jacket for heating or cooling application can be offered.

• Mineral wool insulation with cladding on jacket.

• Tangential designed ‘Z’ blades offered for uniform mixing.

• PTFE made shaft sealing provided for food grade compatibility.

• Minimum gap between trough inner shell & blades removes possibility of sticking product.

• On demand Spray system, vacuum system

Optional Features/Accessories of Sigma Mixer

• Liquid Spray System

• Vacuum System

• Blades Cooling Arrangement

• Screw System

• Automatic Valve Discharge System

Process Operation of Sigma Mixer Machine

In Sigma mixer tangential action of mixing and kneading obtained by ‘Z’ type (SIGMA) shaped kneading blades, which rotates very accurately at different speed towards each other causing product to be transferred from one end to another end. Discharge of the finished product is achieved by tilting the container or through the valves at the bottom or by means of an extrusion screw beside the container.

The mixing action is a combination of bulk movement, stretching, folding, dividing, and recombining of the material. The shearing & tearing action of the material against blades and the side walls causes size reduction of the solids. After the time period required for sterilizing the batch has elapsed, the heating circuit shuts of the pneumatics damper (exhaust) opens and cooling operation commences.

In the tangential design, the blades rotate in the trough meeting tangentially. The front blade generally rotates faster than the rear blade usually in the ratio of 3:2. Tangential blades are generally used for material of higher viscosities such as adhesives, rubber compounds, flush colors, dyes, and pigments.

In the overlapping design, the blades overlap above the saddle of the container. Due to the overlapping action, it is necessary that the relative position of the two blades is unchanged, and as a result, both the blades rotate at the same speed. Materials that flow freely or creep down into the blades are mixed using the overlapping blade action. This design offers a faster interchange of material from one blade compartment of the mixer to the other. Overlapping blade action is used for materials of lighter viscosities such as carbon pastes, clay coating, creams, and ointments. The overlapping blade produces a lower kneading and shearing compared to the tangential blade action.

Technical Specification of 500 Liters Sigma Mixer

* Power voltage can be adjusted as per customer’s domestic power voltage requirements.
* Rights of technical improvements & modification reserved.
* Illustrations & dimensions are shown for information purpose only.