Selecting the correct static mixer: helix, quadro, number of elements and ratio
The static mixer plays a crucial role in ensuring a homogeneous dispensing of a two-component material. Its design, number of elements, diameter, and the appropriate mixing ratio must be compatible with the material and the dispensing device. This article explains how to select the right mixer.
To the point: the right mixer in four questions
- What is the mixing ratio of the material (1:1, 2:1, 4:1 or 10:1)?
- How viscous is it and what volume flow rate (diameter) is required?
- How critical is the mixing quality (number of elements)?
- Which connection fits the cartridge and device?
How a static mixer works
A static mixer consists of a pipe with stationary mixing elements. As the material is forced through, it is repeatedly divided, deflected, and recombined. With each stage, the number of layers increases, and the material becomes more homogeneous. There are no moving parts; the mixing energy comes solely from the extrusion pressure.
Helix or Quadro: two designs
Two designs are common. The helical mixer (for example, the MFH series) uses helical elements that alternately deflect the material. The quad mixer (for example, MFQ and MFQX) works with chamber-like elements and often achieves thorough mixing over a shorter length, which can save material in the mixer and thus reduce waste. Which design is suitable depends on the material, the ratio, and the requirements. The specifications in the material and mixer data sheets are decisive.
| feature | Helix (MFH) | Quadro (MFQ and MFQX) |
|---|---|---|
| elements | helical | chamber-like |
| Construction length | tends to be longer | often shorter with the same mixing quality |
| Strength | proven all-rounder | compact, even for high conditions |
Number of elements and diameter
Two key parameters define the mixer. The number of elements determines the mixing quality: more elements mean more thorough mixing, but also more waste and higher dispensing pressure. The diameter depends on the flow rate and viscosity; low-viscosity materials and small quantities require small diameters, while viscous materials and large quantities require larger diameters. The diameter and number of elements are usually coded in the type designation, for example, MFQ 5.3-24 or MFH 08-24. If in doubt, consult the data sheet or our advisory service.
The mixing ratio must be suitable for the mixer
Mixers are designed for specific ratios. A 10:1 material requires a different inlet and element geometry than a 1:1 material to ensure the smaller component is properly incorporated. Special types exist for higher ratios, such as the MFQX 8.7-24 for 10:1. A mixer unsuitable for the ratio will mix inadequately, even if the ratio and the device are otherwise correct.
Mixer and cartridge as a system
The mixer, cartridge, and dispensing device form a system. The connection, such as bayonet or thread, must fit; otherwise, the mixer will not seal properly. Within a product line, the components are designed to work together. When changing the material or ratio, it is essential to check whether the mixer also needs to be changed.
Selection aid
| situation | Notice |
|---|---|
| High ratio (10:1) | Mixer type for high-pressure applications, such as the MFQX series |
| Minimal waste desired | short overall length, check Quadro |
| tough material or large quantity | larger diameter |
| Small, exquisite quantities | small diameter, syringe dosing if necessary |
| Highest blend quality | higher number of elements |
Typical mistakes when choosing a mixer
- Mixer too short or too few elements: the material remains mixed in.
- The mixer is not suitable for the mixing ratio.
- Incorrect diameter: excessive pressure or uneven discharge.
- The connector doesn't fit the cartridge.
- Mixers can be reused after the pot life has expired.
We will gladly clarify which mixer is suitable for your material and ratio based on the data sheet.
