A shaker is a laboratory equipment used to mix or agitate substances in tubes or flasks, which is mainly used in the fields of chemistry and biology. An orbital shaker has a circular stirring movement and is suitable for growing microbes and mixing in general. The shaker is the option you want to take when working with high volume substances, or simultaneous agitation is required. They are used for liquids and solids of low density.
The term “laboratory shakers” encompasses among others magnetic stirrers, vertical stirrers, hand stirrers and other stirring systems. Automatic shakers have at least two components, a propulsion system and a rod. The propulsion system or engine is responsible for transmitting the movement to the rod and this in turn, is the piece that transmits the movement of the engine to the medium.
There are several rods for laboratory shakers. Only the correct combination between the propulsion system and the rod allows optimal development of laboratory shakers. The rods generate different flows in the medium due to their different types of construction and must take into account the different possibilities of the propulsion system. There are rods such as flat blade stirrers, crescent stirrers, propeller stirrers, turbine stirrers, anchor stirrers and other shapes.
Depending on the environment and the process, laboratory shakers have different functions and possibilities. Initiation laboratory shakers work with a fixed number of revolutions, which are indicated in r.p.m. (revolutions per minute). There are also laboratory shakers with different revolving forces (torque). The indication of the torque force is shown in Ncm (Newton centimeters) and there are laboratory shakers with fixed torque and free adjustment. There are also laboratory shakers that record torque variations and indicate such changes to the user.
There are also laboratory shakers with software that can be remotely managed and allow documenting processes. Other criteria of the propulsion system of laboratory shakers are, for example, space requirements, noise development, safety, reliability and handling.
The main types of agitators are the following:
- Magnetic shaker (with or without heater): It is a metal plate on which a flat bottom vessel containing the liquid or solution that must be stirred is placed. It introduces the shaker magnet and an electric motor under the plate produces magnetic forces that rotate the magnet, causing the circular movement of the liquid. The rotation speed can be controlled. In many cases there is an electric heating system to control the temperature.
- Tray shaker: The tray has a circular motion through a motor that controls it. They can also have rocking movements or vibrations. They are used to move cell cultures. Sometimes they have additional thermostatic control.
- Vortex agitator or vortex mixer: The surface on which the vessel to be agitated is placed is rubber or rubber, is placed in a slightly eccentric position and when rotating produces vortices in the liquid.
- Orbital shaker: They are similar to tray agitators. A platform parallel to the table surface is provided with an eccentric orbital movement.
- Roller shaker: A series of rollers close together rotate in a horizontal plane. The tubes, conveniently closed, are placed on the rollers and the liquid slides on its walls. Used in hematology laboratories, with blood samples and anticoagulant.
- Vertical stirrer: The axis of rotation is vertical. The end that is introduced into the container with the liquid is finished in vanes. They are similar to a blender.
The shakers have been replaced for many purposes by magnetic stirrers, but are still used preferentially in some situations.