Rubber lined Slurry Pump
Rubber Lined Slurry Pump
What is a rubber-lined slurry pump?
A rubber-lined slurry pump is a type of centrifugal pump with special rubber liners that help to protect plants and equipment from wear, abrasion, and corrosion caused by slurry. The rubber-lined slurry pump is the most preferred anti-wear pump for transferring fine particle slurries. Slurry presents in many forms from fine sand to coarse aggregate. Fine particle sand is extremely abrasive and often rapidly wears down conventional slurry pumps. In a rubber-lined slurry pump, the particles hit the rubber surface, which deforms and absorbs the kinetic energy of the particles. Most of this energy is then returned to the particles as a result of the resilient nature of the rubber, causing the particles to rebound with little or no wear. Rubber-lined slurry pumps are perfect for delivering strong corrosive or abrasive slurries of small particle sizes without sharp edges. The pump features a radially split casing design for easier access to the pump internals and a two-part elastomer liner, reducing casing wear from abrasive fluids.
Figure: Showing the configuration of a rubber-lined slurry pump
Most rubber-lined slurry pumps employ a flexible shaft coupling drive which offers the benefits of low cost and easy installation. Rubber line slurry pump manufacturers avail them in both horizontal and vertical configurations. They are designed to pump slurries to a maximum head of 100 meters at high flow rates of up to 1500 cubic meters per hour while operating with a 1200KW motor. Rubber-lined slurry pumps are convenient for a wide range of industrial applications. They are widely used in mining, coal washing, power plant, metallurgy, petrochemical, dredging, etc.
Components of a rubber-lined slurry pump
The pump casing is often made of cast iron and lined with rubber to prevent wear, abrasion, and corrosion in handling slurry. The pump casing houses the impeller and the intake and discharge ports. It also contains the volute chamber which helps with the conversion of the kinetic energy into the pressure head. The rubber-lined slurry pump manufacturers use a radially split casing (i.e., a casing split in the vertical plane and the two haves held together using bolts and location pins) for easier access to the bearing, impeller, and rubber-lined surfaces. The pump casing can also be either diffusing or volute type. A diffusing casing is circular and contains several guide blades, surrounding the impeller in the pump assembly. A volute casing has a spiral design where the pumped liquid’s passage increases gradually all around the casing’s circumference.
The motor is the source of the mechanical power to run the pump. The type of electric motor that is mostly employed in the rubber-lined slurry pump is a two-pole, three-phase squirrel-cage induction motor. This type of motor can operate with a wide range of currents and voltages.
The impeller is the main rotating part of the rubber-lined slurry pump. The main function of the impeller is to displace the fluid through the pump when it rotates. The impeller is designed with blades that help to impart kinetic energy and to increase the velocity of the pumped fluid. The number of impellers in a pump equals the number of pump stages. The rubber-lined slurry pump’s impeller consists of pressure-molded elastomer liners. Rubber-lined slurry pump manufacturers group impellers based on the constructional geometry, the type of suction, and the direction of flow. Pump impellers are usually manufactured from cast steel and close-grained cast iron.
The purpose of the shaft is to transfer mechanical torques from the motor to the impeller during pump operation. The pump shaft is usually coupled with the electric motor. Rubber-lined slurry pump manufacturers create pump shafts from stainless steel and carbon steel. These materials are preferred because they enhance the shaft’s ability to overcome heavy loads and vibrations during the pump operation.
The bearings carry the shaft and the impeller and ensure they align correctly with the fixed ends under the action of radial and axial forces. Bearings also serve to reduce the friction between the rotating shaft and the stator and contain the relative motion of the rotor assembly.
Intake and outlet section
The intake section is the suction manifold and it supplies the pumping fluid to the impeller eye. In applications with low bottom pressure, the pumped fluid may contain a significant amount of gases that can damage the pump. In such applications, a gas separator replaces the intake section to separate the gas from the fluid when it enters the pump. The outlet section allows the pumped fluid out of the pump and into the delivery pipes.
Rubber-lined slurry pump features a two-part elastomer liner that is designed to protect the casing and impeller from extended wear caused by abrasive and corrosive material while improving performance.
Diamond-Core Mechanical Seal
The diamond core mechanical seals enhance the pump performance by preventing leakage of pumped fluid from the pump. It also enhances the efficiency in handling high-temperature and highly corrosive medium.
Figure: Components of a rubber-lined slurry pump.
How does rubber-lined slurry pump work
When the pump is started, the motor rotates the pump shaft and the impeller at a very high RPM. As the impeller rotates, it displaces the priming liquid inside the pump casing, creating a vacuum inside the pump. Due to the atmospheric pressure outside the pump, more pumped fluid is forced into the pump through the suction inlet and toward the impeller’s eye to occupy the vacuum. As long as the impeller rotates the liquid will be continuously sucked in to be transferred. As soon as the liquid strikes the impeller’s eye, the centrifugal force acting on the impeller blades pushes the fluid from the center of the impeller to the outer edges and into the volute casing at a very high kinetic energy and fluid velocity. In the volute casing, the speed of the fluid slowly decreases due to the gradually expanding flow path, and some of the kinetic energy is converted into static pressure energy. The liquid then enters the discharge pipe at a very high pressure which allows it to be moved to the place where it is required.
Figure: Working of a rubber-lined slurry pump
Types of rubber-lined slurry pumps
Vertical rubber-lined slurry pump
This vertical type of rubber-lined slurry pump has a vertically oriented shaft and mostly employs a close coupling between the motor and the pump head. Major benefits of the Vertical rubber-lined slurry pump include less floor space requirement and the ability to lift liquids from an area of higher depth.
Figure: Showing a vertical rubber-lined slurry pump.
Horizontal rubber-lined slurry pump
The horizontal rubber-lined slurry pump involves aligning the pump head on the same horizontal plane with the pump motor. The pump head and the pump motor can be either close-coupled or long-coupled. The main advantages include ease of installation, accessibility, and maintenance of pump components.
Figure: Showing a horizontal rubber-lined slurry pump.
Applications of rubber-lined slurry pumps
The rubber-lined slurry pump caters to a host of applications in different industries such as mining, coal, power plant, metallurgy, petrochemical, chemical, dredging, cement, mineral sand, etc. Typical uses of rubber-lined slurry pumps include the following:
- Rubber-lined slurry pumps are used to transport sand and gravel in sand mines.
- They are used for coal and slurry transportation.
- They are also used for damming and bed silt displacement.
- They also apply in treatments of chemical liquid, acid or base, slurry, and wastewater at low and medium temperatures in chemical plants.
- They are also used in screening, grading, and conveying dense liquid in coal plants
- They are sued in paper mills to treat clay slip, and paper pulp.
- Rubber-lined slurry pumps are also used for transporting porcelain clay and sand & gravel in ceramic and glass plants.
- They are also used to deliver slurry, oxide skin, and corrosive liquid in steel plants.
Advantages of rubber-lined slurry pumps
- The rubber-lined slurry pump presents a strong design. The rubber lining equips the pump with higher corrosion and abrasion tolerance compared to conventional slurry pumps.
- Rubber-lined slurry pumps are easily repairable. The radially split casing facilitates easy access to the pump internals.
- They have a long service life.
- They are suitable for vast application.
- They are lightweight and simple to install.
- The pumps have excellent wear performance.
- The pumps have longer maintenance intervals since the rubber lining reduces wear rate.
- They are safe to install and operate because the rubber is lighter and softer than other wear-lining materials.
- Rubber-lined slurry pumps are perfectly efficient for pumping slurry, gravel, concrete, mud, and slush, without wear. Their combined strength and corrosion resistance create a good slurry pump.
- They have less downtime.
Disadvantages of rubber-lined slurry pump
- Rubber-lined slurry pumps have a low head. The rubber lining is relatively soft and high speed may deform the impeller, causing a low head.
- It has higher upfront costs compared to a conventional alloy slurry pump lined with gray cast iron, black cast iron, or other wear-resistant metals.
Troubleshooting a rubber-lined slurry pump
The motor fails to start
- No power supply to control the Panel. Inspect the main input panel. Check that the power cables are connected according to the rubber-lined slurry pump manufacturer’s guidelines.
- There is a tripped circuit breaker or a blown fuse. Reset the circuit breaker if necessary. Inspect the pump for a blown fuse and replace it if necessary.
- The pump cables are broken. Inspect and replace any broken cables.
The Pump gives zero flow after the startup
- The suction lift is too high. Lower the pump or raise the liquid level in the tank
- The pump is operating in reverse. Reverse the motor polarities. Check that the motor rotation direction is according to the rubber-lined slurry pump manufacturer’s manual.
- The impeller or check valve is clogged. Inspect the impeller and check valves and clear any blockage
- Insufficient manometric head. Ensure all valves are open and pipe diameter of the pipes meets the sizes set by the rubber-lined slurry pump manufacturer
The Pump’s flow rate is unstable
- The pump lifts liquid with air. Check the depth of the suction pipework or valve in liquid and deepen if required.
- The bottom valve is leaking. Inspect the bottom valve for leakage and correct it.
- The voltage is too low, leading to a decrease in pump speed. Check the power supply voltage and adjust it as necessary.
- The pump lifts liquid with air. Check the depth of the suction pipework or valve in liquid and deepen if required.
The pump is noisy and vibrates excessively
- Large misalignment between the pump shaft and the motor shaft. Inspect and realign the shafts.
- Pump bearings are won out. Inspect the bearing for wear and replace if it necessary.
- Some pump components are unbalanced. Inspect and rebalance pump components
- Oblique shaft. Check the shaft and replace it if required.
A rubber-lined slurry pump is a type of centrifugal pump containing special rubber liners that help to prevent wear, abrasion, and corrosion caused by slurry. The rubber-lined slurry pump manufacturers recommend this pump for use in pumping fine particle slurries such as wet sand slurries because of its anti-wear capabilities. When the particles in pumped fluid hit the rubber surface, the rubber liners deform and absorb the kinetic energy of the particles, which is then returned to the particles, causing them to rebound with little or no wear. Rubber-lined slurry pumps cater to a host of applications in different industries such as mining, coal, power plant, and metallurgy, among others. Rubber lining slurry pumps offer many advantages including strong design, excellent wear performance, ease of maintenance, and long service life. The special rubber liners, also make the rubber-lined slurry pump a heavy-duty pump capable of withstanding highly abrasive liquids.