Double Arm Mixers & Sigma Mixers

Used Double Arm Mixing Equipment, Sigma Blade/Z Blade Mixers

Double arm mixers are predominantly used to mix dough and other pasty products. We stock a variety of used double arm mixers including heavy duty sigma (z-blade) mixers. Our inventory of used sigma arm mixers includes PEERLESS as well as BAKER PERKINS, DAY, and READCO equipment in many capacities and horsepower. We are also suppliers of jacketed double arm mixers and most of our double arm mixers have tilting discharge.

FAQ :

What is a double arm mixer and how does it work?

A double arm mixer, also commonly called a sigma blade mixer or Z-blade mixer, is a heavy-duty mixing machine designed specifically for high-viscosity materials that standard mixers cannot handle effectively. The machine uses two counter-rotating blades mounted in a saddle-shaped mixing chamber. As the blades turn toward each other, they create intense shearing, folding, and kneading action that thoroughly combines dense, stiff, or paste-like materials. The sigma blade profile is the most widely used blade shape, though dispersion blades and other configurations exist depending on the application.

The mixing chamber is typically a double-trough design, which is where the "double arm" name originates. This geometry ensures that material is constantly being pulled from the sides and bottom of the bowl and forced through the narrow gap between the blades and the chamber walls. That gap is where most of the shear energy is applied. Many double arm mixers are also equipped with a heating or cooling jacket around the mixing bowl, allowing operators to control the temperature of the batch throughout the process. Discharge is usually accomplished by tilting the entire bowl, which empties the mixed material cleanly and efficiently.

What materials and industries are double arm sigma blade mixers used for?

Double arm sigma mixers are built for materials that are too thick, sticky, or dense for ribbon blenders, paddle mixers, or other conventional equipment. Common applications include bread and pizza dough, pasta dough, hard candy compounds, chewing gum bases, adhesives, sealants, rubber compounds, putty, caulking materials, pigment pastes, and certain pharmaceutical and cosmetic formulations. The machine excels anywhere the product resists flow and requires aggressive mechanical work to achieve a uniform blend.

Industries that rely on double arm mixers span a broad range. Food processing is one of the most prominent sectors, particularly bakeries and pasta manufacturers that need consistent dough development at scale. The rubber and plastics industries use these machines to incorporate fillers, pigments, and processing aids into polymer bases. Adhesive and sealant manufacturers depend on sigma mixers to combine resins, fillers, and curatives into homogenous compounds. Chemical and pharmaceutical producers also use jacketed versions for temperature-sensitive formulations. Because the applications vary so widely, used double arm mixers are available in stainless steel construction for food-grade and sanitary environments, as well as carbon steel for industrial chemical and rubber processing.

What capacity sizes are available in used double arm mixers?

Used double arm mixers are available across a very wide capacity range, making it possible to find equipment suitable for laboratory-scale development work all the way up to full production volumes. On the small end, tabletop laboratory units handle batches of just a few pounds or roughly one to five gallons. These are commonly used in R&D settings, quality control labs, and pilot plant operations where small test batches are needed before scaling up. Brands like C.W. Brabender produce well-known lab-scale double arm mixers in this category.

At the production end of the spectrum, industrial double arm mixers can handle batches measured in hundreds of gallons or thousands of pounds. Units in the 300-pound to 1,200-pound range are common in mid-scale bakery and food processing operations, while larger machines exceeding 1,900 kilograms are used in heavy industrial applications involving rubber, adhesives, or large-volume dough production. When selecting a used machine, it is important to match the working capacity to actual batch requirements rather than simply choosing the largest available unit. Oversized mixers running at partial capacity often produce inconsistent results, while undersized equipment creates production bottlenecks. Capacity is typically expressed in pounds of dough, gallons of material, or cubic feet of bowl volume depending on the manufacturer and application.

What should I look for when buying a used double arm mixer?

Evaluating a used double arm mixer requires attention to both mechanical condition and application fit. Start with the blades themselves. Sigma blades and Z-blades wear over time, particularly when processing abrasive materials. Check for uneven wear, pitting, cracks, or excessive clearance between the blade edges and the bowl walls. Blade-to-wall clearance directly affects mixing efficiency and product homogeneity, so this is not a cosmetic issue. Also inspect the seals and packing around the blade shafts, as worn seals can allow product contamination or lubricant ingress into the batch.

Beyond the blades, examine the drive system including the gearbox, motor, and any variable speed controls. Ask whether the machine has been in recent production or has been sitting idle, since extended downtime can affect seals, lubricants, and electrical components. For jacketed models, inquire about the condition of the jacket and any history of leaks or pressure testing. Stainless steel construction should be inspected for welds, cracks, and surface condition, especially for food or pharmaceutical applications where surface integrity matters. Tilt discharge mechanisms, which are common on production-scale machines, should operate smoothly without binding. Requesting photos, video, or an in-person inspection before committing to a purchase is the most reliable way to assess actual condition.

How do I inspect a used double arm mixer before purchasing?

Reputable used equipment dealers typically offer multiple inspection options to help buyers assess a machine before purchase. In-person inspections allow a buyer or their technician to physically examine the equipment, check blade clearances, review the gearbox and motor condition, operate the tilt discharge mechanism, and look at the overall structural integrity of the mixing bowl and frame. When an in-person visit is not practical, most dealers can arrange a video inspection or provide detailed video footage of the machine, including close-ups of blades, seals, drive components, and any visible wear.

Some machines being sold through dealers are still installed and running at the facility where they were originally used. In those cases, it may be possible to observe the equipment operating under actual production conditions, which provides a much clearer picture of its functional state than inspecting a decommissioned machine on a warehouse floor. One important limitation to keep in mind is that used equipment dealers generally cannot run actual product through a machine for testing purposes, as food or chemical production requires specific permitting and facility certifications that a dealer would not hold. The inspection is therefore focused on mechanical and structural condition rather than a live production trial. Buyers with specific concerns about a particular machine should bring in a qualified mechanic or equipment specialist to assist with the evaluation.

What are the most reputable brands of double arm mixers to look for in the used market?

Several manufacturers have built strong reputations for producing durable, long-lasting double arm mixers, and their equipment tends to hold value well in the used market. Peerless is a widely recognized name in the bakery and food processing sector, known for heavy-duty stainless steel sigma mixers used in large-scale dough production. Baker Perkins has a long history of manufacturing process equipment for food and confectionery applications, and their double arm mixers are respected for consistent performance. Day (also known as Littleford Day) produces laboratory and production-scale sigma mixers used across food, chemical, and pharmaceutical industries. Readco (Teledyne Readco) is another established manufacturer with equipment commonly found in industrial mixing applications.

For pasta and specialty dough applications, Lombi and similar European manufacturers produce purpose-built double arm mixers with tilt discharge that are well-suited to pasta production environments. Shaffer is a recognized brand in the bakery sector for large-capacity dough mixers. When evaluating any used machine, brand reputation matters because it influences parts availability, the depth of service documentation, and the level of manufacturer support a buyer can expect. Older or discontinued models from any manufacturer may have limited parts availability, so it is worth consulting the manufacturer directly before purchasing to understand what support exists for a specific model and age of equipment. A machine from a reputable brand that is well-supported is generally a lower-risk purchase than an obscure brand with no service network.

What is the difference between a jacketed and non-jacketed double arm mixer?

A jacketed double arm mixer has a hollow outer wall surrounding the mixing bowl that allows a heating or cooling medium, typically water, steam, or a glycol solution, to circulate around the batch. This gives operators precise control over the temperature of the material being mixed. For applications like candy compounds, certain adhesives, or pharmaceutical formulations, maintaining a specific temperature range throughout the mixing cycle is critical to achieving the right viscosity, reaction rate, or final product properties. Jacketed mixers are also used in food applications where the dough or paste needs to stay within a controlled temperature window to avoid overheating from the friction generated during intensive mixing.

Non-jacketed mixers are simpler in design and are commonly used for applications where temperature control is not a process requirement, such as mixing bread dough at ambient conditions or blending materials that are not sensitive to heat buildup. The absence of a jacket reduces cost and maintenance complexity. When buying a used jacketed double arm mixer, it is important to ask about the condition of the jacket, including whether it has been pressure tested and whether there is any history of leaks or repairs to the jacket welds. A compromised jacket can be expensive to repair and may render the temperature control function unreliable. Non-jacketed units are generally easier to evaluate for condition since there are fewer internal components to assess.

Are replacement parts and blades available for used double arm mixers?

Parts availability for used double arm mixers varies considerably depending on the brand, model, and age of the equipment. For well-established manufacturers like Peerless, Baker Perkins, and Readco, many replacement parts including sigma blades, shaft seals, gearbox components, and drive parts are still available either directly from the manufacturer or through aftermarket suppliers. These brands have large installed bases, which creates enough demand to keep parts in circulation. However, older or discontinued models from any manufacturer may present challenges, and it is worth contacting the manufacturer before purchasing a used machine to confirm what level of parts support is available for that specific model.

Sigma blades and Z-blades are often the highest-wear components in a double arm mixer, and replacement blades can sometimes be sourced from third-party fabricators even when the original manufacturer no longer supports a particular model. Custom blade fabrication is an option for some applications, though it requires precise measurements and material specifications to maintain proper clearances and performance. Shaft seals, bearings, and gearbox internals are generally more standardized and easier to source through industrial supply channels. Buyers purchasing a used machine should factor potential parts costs into their total investment estimate, particularly if the equipment shows signs of blade wear or seal deterioration at the time of inspection.

What does tilt discharge mean on a double arm mixer, and why does it matter?

Tilt discharge refers to a mechanism that allows the entire mixing bowl to rotate or tip forward, emptying the mixed batch by gravity rather than requiring operators to manually scoop or scrape the product out. On production-scale double arm mixers, this is a significant practical feature because the materials being mixed, such as stiff dough, adhesive compounds, or rubber batches, are typically too dense and sticky to pour or pump out of a stationary bowl. Tilting the bowl allows the batch to fall cleanly into a receiving container, conveyor, or extruder below the machine, reducing labor, cycle time, and product waste.

For operations running multiple batches per shift, tilt discharge also improves throughput and makes cleaning easier since the bowl can be tilted and rinsed out more thoroughly than a fixed bowl design. Many used double arm mixers available on the market are equipped with tilt discharge as a standard feature, particularly at production capacities of 50 pounds and above. When inspecting a used machine with tilt discharge, it is important to verify that the tilting mechanism operates smoothly, that the locking hardware functions correctly, and that there is no excessive play or wear in the pivot points. A malfunctioning tilt mechanism can create safety hazards and operational downtime, so its condition should be a specific focus during any pre-purchase inspection.

What should buyers understand about shipping and payment when purchasing a used double arm mixer?

Shipping a used double arm mixer involves more logistical complexity than shipping lighter industrial equipment. These machines are heavy, often ranging from several hundred to several thousand pounds, and require proper palletization or custom crating to prevent damage in transit. Larger production-scale mixers may need professional rigging services for loading at the seller's facility and unloading at the buyer's location, which adds to the total landed cost. Buyers should ask the dealer specifically about packaging standards, rigging requirements, and freight options before finalizing a purchase, since these costs can vary significantly based on machine size, destination, and the level of protection required.

On the payment side, most used equipment dealers require full payment prior to shipping the machine. Some dealers may offer payment terms to established repeat customers, but buyers purchasing for the first time should expect to pay in full upfront. Understanding the complete landed cost, which includes the machine price, any rigging fees, packaging, freight, and applicable taxes or import duties for international purchases, is essential for accurate budgeting. Buyers should request an itemized breakdown of all costs from the dealer before committing to a purchase so there are no surprises when the machine arrives.