Are you trying to decide between a rotor stator homogenizer and a high pressure homogenizer for your application? While there is certainly some crossover in terms of what tasks each are suitable for, chances are one or the other will be a better fit for your needs.
In this article, we’ll compare the two technologies, looking at the pros and cons of each. We’ll also provide a summary of their features and functionality and reveal the types of applications they are most suitable for.
Rotor Stator Homogenizers
Rotor stator homogenizers use shear force to process samples. The rotor component is a metal shaft that rotates at fast speeds within the stator (a metal casing that remains stationary). The rotor rotation results in a suction effect that pulls the sample into the high-shear environment between the stator and rotor.
Pros of Rotor Stator Homogenizers
- The ability to switch probes means you can process a broad range of sample sizes.
- Some models have no maximum volume which means they are ideal for scaleup processes.
- Single samples can be processed quickly and efficiently.
- Rotor stator homogenizers are a good choice for processing liquid samples.
- You can choose from a selection of probe types such as saw tooth for tissue samples or flat bottom for gentler processing.
Cons of Rotor Stator Homogenizers
- You’re usually limited to processing single samples (multi-sample units are available but pricey).
- Heat is created during processing so a cooling method is required for heat-sensitive samples.
- Rotor stator homogenizers aren’t suitable for solid samples.
- This can be a time-consuming and labor-intensive solution for multiple samples, particularly if probes need to be washed between each sample.
- Pre-processing may be required for fibrous or hard samples.
High Pressure Homogenizers
High pressure homogenizers subject liquid samples to very high shear forces. The process can work slightly differently depending on the model, but typically, the sample is forced through a narrow channel, for example, a valve or small openings in a membrane. This results in high shear forces, a pressure drop, and cavitation, homogenizing the sample. Some setups also involve the high pressure stream colliding with a plate, blade, or ring, aiding in homogenization.
Left to right: A ShearJet® HL60 Electric Hydraulic High Shear Homogenizer and a Micro DeBEE High Pressure Homogenizer.
Pros of High Pressure Homogenizers
- They are suitable for processing large liquid samples.
- Processes are highly reproducible and generally readily scalable, making these ideal in industrial applications such as food processing.
- High pressure homogenizers can produce very small particle sizes.
- Some units have no max volumes as you can continuously feed material into the homogenizer.
- Many models offer lots of flexibility, so the process can be suitable for a range of applications.
Cons of High Pressure Homogenizers
- They aren’t suitable for multi-sample applications.
- Cleaning between samples is time-consuming and labor-intensive.
- These units are often large and heavy, so not easily portable.
- They tend to be on the expensive side so make the most economical sense for large sample processing, although models are available that can handle smaller samples.
Summary of Rotor Stator Homogenizers Versus High Pressure Homogenizers
Rotor stator homogenizers and high pressure homogenizers can be suitable for many of the same processes. They can both handle large, liquid samples and their processes can easily be scaled up. That said, there are some differences.
High pressure homogenizers can offer more efficient thorough processing of large volumes. When it comes to maximum sample size, with a rotor stator homogenizer, very large volumes are limited to scaleup production models. With a high pressure homogenizer, you can often continuously feed sample into the unit, allowing for effectively unlimited volumes even with lab-scale models.
That said, high-pressure homogenizers are large and cumbersome, and don’t come cheap, so may not be worth the investment for some labs. In addition, they are more tedious to clean between samples, making their use more labor-intensive. This, along with the fact they can handle lower volumes, generally makes rotor stator homogenizers a better choice for smaller samples when very small particle sizes are not required.
Neither technology is particularly suitable for high-throughput applications, although there are some multi-sample rotor stator homogenizers available. Heat is generated with rotor stator homogenizers, but it’s relatively simple and inexpensive to add a cooling system to the setup. High pressure homogenizers create more heat, but many systems have the option of a built-in heat exchanger. These are simple to use once set up, but can be expensive.
Some of the core features of each technology are summarized below:
High Pressure Homogenizer
Min particle size: ~2–3 µm
Min particle size: ~100 nm
0.03 mL and up
~10 mL and up (or 0.5–35 mL for a French Press)
Easy to scale up
Highly suitable for scaleup
Some heat generated
Significant heat generated
Ease of Use
Easy to set up and good for single samples
Time-consuming to set up but good for large single samples
Fairly simple to clean between uses
Cleaning can be labor-intensive
~ 10,000 cP
~ 100,000 cP (may require air pressure at higher viscosities)
Of course, choosing the right process will depend heavily on its suitability for your general application. Here are some of the more common applications each technology is used for:
Rotor Stator Homogenizer
High Pressure Homogenizer
General particle size reduction (> 1 µm)
Cell disruption (especially a French Press)
Particle size reduction (> 100 nm)