A centrifugal pump is one of the simplest pieces of
equipment in any process plant. Its
purpose is to convert energy of a prime mover (a electric motor or turbine)
first into velocity or kinetic energy and then into pressure energy of a fluid
that is being pumped. The energy changes
occur by virtue of two main parts of the pump, the impeller and the volute or
diffuser. The impeller is the rotating
part that converts driver energy into the kinetic energy. The volute or diffuser is the stationary part
that converts the kinetic energy into pressure energy. The process liquid enters the suction nozzle
and then into eye (center) of a revolving device known as an impeller. When the impeller of the centrifugal pump
rotates, it spins the liquid sitting in the cavities between the vanes outward
and provides centrifugal acceleration. As the liquid leaves the eye of the impeller,
a low-pressure area is created causing more liquid to flow toward the
inlet. Because the impeller blades are
curved, the fluid is pushed in a tangential and radial direction by the
centrifugal force. This force acting
inside the pump is the same that keeps water inside a bucket that is rotating
at the end of a string. The advantages
of centrifugal pumps include simplicity, compactness, weight saving, and
adaptability to high-speed prime movers. One disadvantage of centrifugal pumps
is their relatively poor suction power. When the pump end is dry, the rotation
of the impeller, even at high speeds, is simply not sufficient to lift liquid
into the pump; therefore, the pump must be primed before pumping can begin. For
this reason, the suction lines and inlets of most centrifugal pumps are placed
below the source level of the liquid pumped.
A vacuum system consists of one or more vacuum pumps
which are connected to a chamber. Vacuum systems work by creating a difference
in pressure. The initial suction is
created by the reduction of pressure inside the vacuum tube, either with the
use of a pump or a motor. Atmospheric pressure sucks the air into the vacuum
system to return the pressure levels to normal. The first pump produces the
vacuum; the second pump contains whatever apparatus requires the use of the
vacuum. In between the two pumps there may be various combinations of tubing,
fittings and valves. These are required for the vacuum system to operate.
Additionally, one or more vacuum gauges are usually connected to the vacuum
system to monitor pressure. A vacuum system consists of a Pressure sensor,
Vacuum system - the containment vessel for the vacuum and the vacuum pumps. The
connectors between the parts of the vacuum system are very important. Vacuum
systems are used in households as well as manufacturing. There are different
types/models of vacuum systems available. Every model of vacuum system offers
slightly different features, but all vacuum systems work on the same basic
principles. Vacuum systems are commonly used in manufacturing and robotics
installations.
