The process for choosing a centrifuge can be complex, as there are many basic variables to consider if you want to make a good choice.

In Ortoalresa, we consider that it is essential to simplify this task, so the user can identify the equipment needed based on not just some variables, but also considering their preferences. To facilitate this work, we have defined this guide for choosing centrifuges, taking into consideration some of the characteristics of the equipment to serve as guides to refine the search based on manners of working.

The basic information needed to start is the following:

1. Characteristics and properties of the tubes to be processed: length, diameter and RCF tolerance.

The support for the sample must be able to bear the centrifugal force it will be subject to. In general, there are materials that due to their properties are more resistant, such as some plastics (polypropylene, polyethylene, Teflon) and other materials that are less resistant, such as glass, which generally does not support RCF values above 4.000 xg.

The size of the tubes is totally decisive for choosing the centrifuge, as it will determine the choice of the equipment you need. The chart you can check on the section “tubes references” will gives more information.

The versatility of a centrifuge comes from the configuration of its accessories. Each series of equipment has a chart of rotors containing information about the adaptors available for them. In addition, we can enlarge this feature even more by designing multiple adaptors to process tubes with different bottoms with a single set of adaptors.

2. Maximum required speed and max. RCF

A centrifuge operates by applying a force to the sample that will produce separation of elements according to density. The different kinds of samples processed and their properties, as well as the different types of results needed by the users makes it indispensable to know this value in order to obtain the desired results.

When choosing equipment, it is necessary to consider the maximum RCF values, or lacking this, the RPM needed for the work.

To compare maximum RCF and RPM values of our equipment, please refer to the information you can find in the section “maximum speeds”.

3. Number of tubes to be processed per cycle.

One of the requirements to make the right choice is to know the number of samples to be processed per cycle. This value, combined with the volume of the tube required, will define the size of equipment needed.

As a guide, please refer to the chart “tubes dimensions/max. capacities”, where you will find the maximum number of tubes that can be placed in each of our machines according to their volume.

4. Type of centrifuge according to temperature control.

Temperature is one of the most relevant physical properties in centrifuges, even though not so much attention is given to it generally. Nevertheless, due to its importance, it is mentioned specifically in the section titled “temperature control: cooling and heating”.

5. Type of rotor required.

The type of rotor chosen as well as its maximum speed will affect the type of sample separation.  In this type of centrifuges, the most commonly used rotors are angle fixed and swing out.

In an angle fixed rotor, the tube remains in the same position during the entire centrifugation process. In general, for the same tube volume, they can spin faster than swing out rotors. These rotors produce an oblique separation in the sample with regard to the mouth of the tube. Therefore, they are recommended for processes that require greater RCF or in cycles that require partial extraction of the supernatant.

Swing out rotors move the sample from vertical position up to 90º with regard to the rotation axis. They normally have a greater number of positions per rotor. They are chosen to provide separations that can be directly read from the tube, obtaining pellets and complete extraction of some of the bands.

After this first stage, you can refine the search based on:

6. Other technical characteristics.

What will really define the equipment you need is the combination of all of them. To facilitate the choice, on the section “comparative chart” you can compare equipment based on the features considered more important for your processes.

7. Type of equipment control.

The type of screen the centrifuge has will define the user’s interaction with the equipment.

Our centrifuges have three types of controls: LED, LCD and TFT, all of them display messages on routine operation as well as warnings regarding the operation and status of the equipment. These screens can also be used to customise certain actions such as the opening of the lid at the end of the process, time to start, etc.

You can check information on this in the section “types of screens”.