Centrifugal Separators
Commonly referred to simply as centrifuges, separators have been in high demand for decades in a number of industries. Aerospace, medical, chemical, seismological, industrial and biotechnical applications abound as both analytical and preparative centrifugal separators allow for continued research and understanding of everything from astronaut and pilot physiology under extreme conditions to viruses at the molecular level in a controlled environment. These mechanisms are also common to food and beverage, agriculture and dairy applications and are heavily implicated in the production of wines, milk, cream and edible oils such as olive or vegetable oil. Textile operations also utilize centrifugal separators in washing and drying mechanisms which are similar to those found in home appliances. As uses abound, the size and degree of force that a specific device can exert will help to determine its applicability and usage. Additional considerations for a new or used centrifuge purchase include sorting needs, production rates, adjustable features and overall size.
No matter the application the basic function is the same for all centrifugal separators. The main body, or cavity, is attached to a fixed central axis about which it spins. This metal or plastic element is most commonly cylindrical or conical in shape and will house the materials to be sorted. A motor forces movement along the perpendicular axis causing the vessel to spin. When optimal acceleration is reached materials flow into the bottom of the separator. The rotational pull causes denser particles to separate out in a radial direction first and then lighter ones. The materials are effectively separated into layers based on their mass. In applications where gravitational pull alone is not sufficient or desirable for separation, special gels or fine meshes may be used. This essentially reverses the separation as smaller particles pass through the mesh to the outer diameter of the tubing while large particles are trapped by an inner screen or sieve. Collected particles can be scraped off the screen or, in some cases, they will slide down to a collection reservoir at the end or bottom of the centrifuge. The level of acceleration, measured as G-force, is critical to the success of a centrifugal separator. In general, the higher the rate of
speed the faster suspensions will separate. It is important to consider the particulates to be sorted as solids may include anything from metal parts to blood cells while liquids and gases can be as innocuous as water or as volatile as toxic waste.
