In order to help our customers to select the correct slurry pump for their specific application, we have to know the definition of the slurry, slurry characteristics, slurry pump first. Now i am glad to share them with you.
1.1 Definition of A Slurry
A slurry is a mixture of any liquid combined with some solid particles. The combination of the type, size, shape and quantity of the particles together with the nature of transporting liquid determine the characteristics and flow properties of the slurry.
1.2 Characteristics of A Slurry
Slurries can be broadly divided into two general groups of non-settling or settling types. Non-settling slurries entail very fine particles which can form stable homogenous mixtures exhibiting increased apparent viscosity. These slurries usually have lower wearing properties but require very careful consideration when selecting the correct pump and drive, because they often do not behave in the manner of a normal liquid. When fine solids are present in the slurry in sufficient quantity to cause this change in behaviour away from a normal liquid, they are referred to as being non-Newtonian.
Settling slurries are formed by coarser particles and tend to form an unstable mixture and therefore particular attention must be given to flow and power calculations. These coarser particles tend to have higher wearing properties and form the majority of slurry application. This type of slurry is also referred to as being heterogeneous.
1.3 What is A Slurry Pump
There are a large number of differing pump types used in the pumping of slurries. Positive displacement and special effect types such as Venturi eductors are used but by far the most common type of slurry pump is the centrifugal pump. The centrifugal slurry pump utilizes the centrifugal force generated by rotating impeller to impart energy to the slurry in the same manner as clear liquid type centrifugal pumps.
However, this is where the similarities end.
Centrifugal slurry pumps need to consider impeller size and design, its ease of maintenance, the type of shaft seal to be used and the choice of the optimum materials. This is needed to withstand wear caused by the abrasive, erosive and often corrosive attack on the material. Many other important considerations are also required.
The centrifugal slurry pump must be designed to allow the passage of abrasive particles which can at time be extremely large.
Slurry pumps therefore need much wider and heavier impellers to accommodate the passage of large particles. They must also be constructed in special material to withstand the internal wear caused by the solids.
To achieve lower operation speed, slurry pumps are also generally larger in size than a comparable clear liquid pump in order to minimise wear within the pump. Bearing and shafts also need to be much more robust and rigid.