Slurry pumps Throughout transfer materials in coal, copper, iron ore, phosphate, and other mining operations. They are also employed on dredges that clear waterways, environmental cleanup, and land reclamation. throughout the world, Slurries, by definition, are abrasive, necessitating the replacement of the impeller, casing, and suction liner wet end parts at regular intervals. It is common to devour six liners, three impellers, and two casings in a year. Slurry pump wear parts are anticipated to cost around $500 million yearly.
One of the pump’s most significant parts and accessories is the slurry pump impeller. The slurry pump can meet the equipment’s requirements when the impeller is spinning. However, it is a component that wears out quickly. As a result, the material plays a significant role in ensuring the impeller’s long service life.
What is Slurry Pump Impeller?
A centrifugal pump’s impeller is a revolving component. Accelerating the fluid away from the center of rotation transfers energy from the pump motor to the fluid being pumped. There are three varieties of impellers: open, closed, and semi-closed, with 2 to 6 vanes in each, depending on the use.
Which type works best for pumping slurry?
Technically, any impeller might be used for slurry applications. However, open impellers are typically favored because they want to avoid wan silt as quickly. Closed impellers perform poorly with materials and are more difficult to clean if they become clogged.
When pumping slurry, the size of the pump’s impeller must also be considered. Slurry impellers are typically larger than those used in pumps that transfer less abrasive liquids. These larger impellers are more resistant to the abuse that strong slurry mixes may dish out. The slower pace comes with, the larger size. The slower the pump runs, the less wear and tear on the impeller.
Types of Impellers
Slurry pump impellers are classified into three types: open, closed, and semi-open. Depending on the use, each offers advantages and disadvantages. Some are better for handling solids, while others are useful for high efficiency.
Closed Design
Closed impellers are made up of two solid plates that are joined to both sides of the blades. After entering the eye and passing through the vanes, the impeller media is drawn into a nozzle and discharged. Because closed impellers do not require vane/casing tolerance, they are more efficient by using wear rings to avoid media recirculation back to the eye.
Open Design
Open impellers are just a set of vanes connected to a central “hub” meant to be fastened to a shaft. The open impeller prevents significant volumes of fluid or gas from recirculating back through the eye by placing the vane ends very close to the pump casing.
In slurry applications, any impeller can be utilized. However, closed slurry pump impellers are more prevalent due to their excellent efficiency and abrasion resistance. Because they are less likely to clog, open slurry pump impellers are commonly utilized for high-concentration materials. For example, tiny fibers in paper stock may tend to clog the impeller at high densities. Pumping slurry can be challenging, and a blocked pump should be avoided at all costs.
Impeller Size
Its size must be evaluated to ensure that the pump’s impeller can withstand abrasive wear. Slurry impellers are typically greater in size than pumps used for less abrasive liquids. The more “flesh” an impeller has, the better it will perform when pumping challenging slurry combinations. Consider the pump’s impeller the offensive line of a football team. These players are typically big and slow. They are beaten up repeatedly throughout the game yet are expected to resist the violence. Small players are undesirable in this role, much as a small impeller on a slurry pump is undesirable.
Impeller Pump Speed
Your process speed has little to do with impeller selection, but it impacts impeller life. It is critical to locate the sweet spot that permits the pump to run as quickly as possible while keeping sediments from settling and clogging. Due to its abrasive nature, the slurry can soon destroy the impeller if you pump too rapidly. This is why a larger impeller should be chosen.
When dealing with slurry, you should generally go bigger and slower. The thicker the impeller, the more durable it will be. The slower the pump, the less wear and tear on the impeller. When dealing with slurry, the impeller isn’t the only element to be concerned about in your pump. Most of the time, rigid, long-lasting building materials are required. Slurry applications frequently use metal liners and wear plates.
Impellers in Pumps
When fluid or gas media enters an impeller pump, it becomes trapped between the impeller vanes and the pump wall, increasing in velocity as it goes from the impeller eye (center) to the impeller’s outside diameter. When the media reaches a specific point near the outer diameter, its velocity abruptly falls, and pressure increases (according to Bernoulli’s principle). As the medium is expelled from the impeller and through the pump opening, it becomes even more pressured. Based on these operating principles, it is clear that the rotational speed (which affects velocity) and vane height (which affects pressure and the possibility of a vacuum) of a pump impeller greatly influence the pump’s output pressure and flow.
Impellers for Mixing
Impellers are commonly used in circulation tanks to mix fluids and slurries. Mixing impellers are typically open in design and are attached to a central shaft in the tank’s center.
When installing an impeller in a tank, it is critical to distinguish between axial and radial flow types. (For further information on flow, see Flow Direction.) Radial impellers typically feature rectangular vanes and are utilized when the tank medium is highly viscous or comprises two immiscible fluids.
Types of radial flow impellers include:
Radial Flow Anchor
An impeller developed for mixing goods with a higher viscosity. A typical anchor is “U” shaped and follows the curvature of the tank. Anchor impellers are custom-made to meet the process. Anchor impellers sweep the entire perimeter of a tank, including the sides and bottom.
Radial Flow Paddle
An impeller developed for mixing goods with a higher viscosity. A typical anchor is “U” shaped and follows the curvature of the tank. Anchor impellers are custom-made to meet the process. Anchor impellers sweep the entire perimeter of a tank, including the sides and bottom.
Radial Flow Turbine
Used for blending. Turbines are multi-blade impellers that transfer media outward to the tank’s edge. Turbines of various varieties enable optimum fluid circulation throughout the mixing vessel.
Characteristics of Impeller Slurry Pump
Impellers can be configured to impart different flow characteristics to pump or tank fluid. Impeller flow designs can be classified into axial, radial, and mixed. Because centrifugal pumps are likewise classed in this fashion, selecting an impeller depends on matching the flow characteristic of the pump to that of the impeller.
- Axial flow impellers move media in a direction parallel to the impeller.
- Radial flow impellers transport material at right angles to the impeller.
- Mixed-flow impellers exhibit both axial and radial flow characteristics. They may move media at an angle other than right angle radial flow.
Examples of the necessity for non-standard impellers include
Pumping coarse coal
With a conventional 5-vane closed impeller, large particles might cause blockages. A unique large-particle 4-vane impeller may be required.
Fibre material pumping
Long fibers may become entangled in the vane entry of ordinary impellers. For these tasks, a customized choke-less impeller can be employed.
Reduced diameter impellers
Reduced diameter impellers are sometimes required but are generally avoided since impeller wear is more than with complete diameter impellers.
Reduced eye impellers
A customized impeller with a decreased eye can extend impeller wear life in some particularly high-wearing applications, such as mill discharge.
Impellers vs. Propellers
Impellers are very similar (or even identical) to propellers at first glance, and the terms are frequently used alternately in the fluid power business. Indeed, both propel and impel are defined as “driving or moving forward.” Still, the two are employed in industrial applications to represent two separate machines that drive two different things or substances.
Propellers are widely used to describe devices that move a connected object. A ship’s propeller, for example, propels the ship forward or backward. On the other hand, Impellers are designed to move the fluid or gas passing through them without displacing the object to which they are attached.
Polyurethane Slurry Pump Impellers Have Several Advantages
Polyurethane impellers have demonstrated their usefulness in several industries, including chemical, electric power, coal, metallurgy, and construction materials. Polyurethane is resistant to oxidation and tear, allowing it to endure seawater, acid, alkali, and salt.
Polyurethane impellers have a longer lifespan, which minimizes the frequency with which they must be replaced. Because the material is smooth, the slurry is unlikely to attach to the impeller and block the pump.
These advantages add up to increased efficiency and fewer problems when pumping slurry.
If you have any questions about the impeller of the slurry pump, please feel free to contact us to answer your questions as soon as possible
