Tank mixers are one of the most common pieces of equipment in batch processing, and one of the easiest to specify badly. Choosing the wrong configuration or undersizing the drive costs you cycle time on every batch for the life of the machine. This guide covers what tank mixers are, how they differ from inline systems, the main types available and how to size one for your vessel.
What is a tank mixer?
A tank mixer is a mixing unit mounted into a vessel so the product is processed where it already sits, rather than being pumped through an external machine. The mixing head is driven on a shaft entering the tank from the top, the bottom or occasionally the side, and the whole batch is worked in place until it reaches the required consistency. They are also referred to as in-tank mixers or tank agitators.
Tank mixers vs inline mixers
Tank mixers process a complete batch inside one vessel. Inline mixers sit in the pipework and process product as it passes through, either in a single pass or by recirculating it back to the tank.
The choice usually comes down to three things: whether the product must stay in one vessel for batch integrity, how the line will be cleaned, and whether you need the whole batch brought to a uniform state or a controlled amount of work applied to a flowing stream. Where traceability per batch matters — pharmaceutical and many food applications — tank mixing is often the simpler route.
Types of tank mixer
Top-entry mixers are the most common configuration. The drive sits above the vessel and the shaft enters through the lid, which makes them straightforward to retrofit to tanks already in service and easy to access for maintenance.
Bottom-entry mixers enter through the base of the vessel. They suit tanks with limited headspace, and the unobstructed path to the rotor makes them better at handling large particulates. They are also a good fit where a sealed entry point is preferred.
Low shear mixers and agitators cover the gentler duties — blending, suspension, mass movement and scraped-surface work — where the goal is to move product around the vessel rather than to break it down.
How to size a tank mixer
Sizing starts with the batch, not the motor. The working volume of the vessel sets the broad range, but the product decides the rest: a low-viscosity blending duty and a high-shear dispersion duty in the same 1,000L tank call for very different machines. Viscosity, the solids you need to wet out or break down, the vessel geometry and the hygiene standard the line must meet all shape the final specification.
The table below gives the working ranges across the AE Mixers in-tank range as a starting point. Figures are based on water-like liquids with a general-purpose head fitted, and reduce progressively as viscosity increases.
| Model | Entry | Batch size | Best suited to |
| ADSI High Shear Top Entry | Top | 5L – 12,000L | General-purpose batch mixing; vessel-mounted or on a lifting stand for interchangeable vessels |
| ADSB Sealed Bearing | Top | 25L – 5,000L | Exposed applications; the shaft runs guarded inside a central support tube |
| ADBE High Shear Bottom Entry | Bottom | 25L – 15,000L | Large particulates and viscous products; unobstructed rotor opening, pairs with an anchor stirrer |
| AETED / AEBED Dispersion | Top or bottom | 25L – 5,000L | Intense dispersion duties across food, pharmaceutical, cosmetic and chemical processing |
| Low Shear Mixers & Agitators | Top, bottom or side | Custom-engineered | Blending, suspension, mass movement and scraped-surface duties; CIP and pressure-sealed options |
Should you choose top-entry or bottom-entry?
Top-entry units are the more common choice and are simpler to retrofit to an existing tank. Bottom-entry units suit vessels with limited headspace, or processes that benefit from a sealed entry point and an unobstructed path to the rotor — which also makes them better at handling large particulates. Where a process is new or a product is changing, a trial is the most reliable way to settle it before committing.
Cleaning, hygiene and CIP
Tank mixers can be built in food-grade stainless steel and supplied in hygienic designs suitable for clean-in-place operation. This matters most where changeover time drives throughput, or where cross-contamination between batches is a real risk — in those cases the cleaning regime should be part of the specification from the start, not added afterwards.
Can a tank mixer be fitted to a vessel you already have?
In most cases, yes. Mixers can be supplied as standalone units or retrofitted to vessels already in service, and can be mounted on a lifting stand where one unit needs to serve several interchangeable vessels, bins or containers. That often makes upgrading an existing line considerably cheaper than replacing the vessels.
Getting the specification right
If you are specifying a tank mixer for a new process, the quickest route to the right answer is usually to run the product. AE Mixers offers process trials so a configuration can be confirmed against your actual material before an order is placed. You can see the full in-tank mixer range, or contact us to discuss your application.
