The Double Arm sigma mixer is a commonly used mixer for high viscosity materials. This article details the construction of the sigma mixer, design and operational features, and its applications. The different variants of the sigma mixer design are discussed.

The sigma mixer is one of the most popular used for mixing and kneading high viscosity materials. It belongs to the family of double arm kneader mixers.

Double Arm Sigma Mixer

• Stainless Steel Exterior
• Overall Dimensions -

• Tilting Bowl
• Stainless Steel Bowl Sheet
• Fabricated Bowl Ends
• Refrigeration - Water/Glycol

• Double Sigma Arm Sigma Mixer- Stainless Steel
• Agitator Spider - Solid Hub
• Stainless Steel Agitator Shaft
• Agitator Shaft Seals - Split Clipper

• Stainless Steel Construction
• Liquid Inlets - Two (2) Diameter - 2"Type - Bevel Seat
• Liquid Inlets - One (1) Diameter - 1-1/2"Type - Tri Clamp
• Flour Gate - 12" square flange, slide gate missing
• Bowl Seals - Side - Rear

• Double End Differential Drive
• Motor- 50/25 HP, Two Speed - motor tag missing estimate 50/25 hp
• 460 Volt, 3 Phase, 60 Hertz
• Agitator Speed - 40/80 RPM
• Drive Design uses Chain and Sprockets 80-3, 60T/20T

• Mechanical Bowl Tilt , Tilt Drive - Spur Gear
• Tilt Degrees - 90

• Stainless Steel Operator Control Panel w/
  Push Button Controls

Working Principle of Sigma Mixer

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 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.