Stainless Steel Magnetic Drive Centrifugal Pump
Stainless Steel Magnetic Drive Centrifugal Pump
What is stainless steel magnetic drive centrifugal pump?
This is a magnetic drive pump made of stainless steel materials that use impellers to cause fluid flow. Unlike other centrifugal pumps, this type of pump is seal-less having the motor and pump coupled by use of magnetic technology instead of a mechanical shaft. Stainless steel magnetic drive centrifugal pump manufacturers produced these pumps for over 7 decades. However, they became more popular in recent years due to new legislation and stringent industrial requirements about fugitive emissions, especially in the petrochemical and chemical industries. This type of pump is made of stainless steel due to its superb mechanical and thermal properties making it handle high pressure and temperature such as in steam power plants comfortably. Stainless steel magnetic drive centrifugal pump manufacturers design this pump with two magnets that is the drive and inner magnets. The two magnets not only help the pump to operate but also prevent fluid leakage.
Figure: Stainless steel magnetic drive centrifugal pump
Components of a stainless steel magnetic drive centrifugal pump
The magnets are used to transmit torque between the motor and the pump. The drive magnet is mounted on the motor while the inner magnet is mounted inside the pump. The magnets are arranged with their poles opposite to allow rotary force due to the magnetic field pattern.
This is the component that provides the energy needed to operate the pump. The motor converts electrical energy into mechanical energy. The mechanical energy is transmitted to the pump via the motor shaft and the magnets.
This is the part of the pump that is used to force the fluid from its source into the pump. The impeller rotates relative to the motor speed. The rotation helps to impart velocity to the fluid so that it can move through the pump.
This is the shaft on which the impeller is mounted. The shaft is supported on bearings to allow the impeller rotate smoothly and at low friction.
The casing is the part that encloses the impeller and other internal parts. Stainless steel magnetic drive centrifugal pump manufacturer design the casing such that the liquid’s kinetic energy exited at the discharge port is transformed into pressure energy before the fluid leaves the casing.
Suction pipe and foot valve
A suction pipe is used to connect the pump to the liquid source. One end of the suction pipe is connected to the pump inlet port and the other end is dipped into the sump. A foot valve is fitted on the lower end of the suction pipe. The valve opens in an upward direction allowing fluid flow. Magnetic pump manufacturer also design the pump with strainers to help filter unwanted materials getting into the pump.
This valve has two ends in which one is connected to the discharge end of the pump and the other end is connected to the pipe delivering fluid.
Figure: Components of a stainless steel magnetic drive centrifugal pump
How does a stainless steel magnetic drive centrifugal pump work?
A stainless steel magnetic drive centrifugal pump is named so because it uses magnetic coupling to transmit torque from the motor to the pump impeller. The magnetic field is due to the use of magnets arranged with opposite poles. There is a magnet on the motor side and another magnet on the pump side. When the motor is turned on, the motor shaft rotates, and thus the motor magnet spins. As a result, the inner magnet starts rotating owing to the magnetic field pattern. The rotation of the inner magnet also forces the impeller to start rotating at a high speed relative to the motor speed.
The impeller rotation causes a vacuum in the pump. Due to this vacuum, the atmospheric pressure on the surface of the liquid forces the liquid into the pump. As the fluid gets into the pump, the impeller imparts kinetic energy into it. The fluid then moves into the pump casing. In the casing, the fluid’s kinetic energy (velocity) starts reducing as the fluid pressure energy increases. The pressure energy is used to transport the fluid from the sump to indented location.
Figure: Working of a stainless steel magnetic drive centrifugal pump
Types of stainless steel magnetic drive centrifugal pump
Submersible stainless steel magnetic drive centrifugal pump
This is a pump that operates by being submerged in the fluid being pumped. The motor is hermetically sealed to the pump body to prevent damage from the fluid. This type of pump helps to prevent cavitation which is common when there is a high difference between the fluid surface and the pump. The pump works by pushing the media to the surface. These pumps are suitable for use in deep wells and pits such as rainwater, commercial, municipal, household, and industrial applications.
Figure: Submersible stainless steel magnetic drive centrifugal pump.
Horizontal stainless steel magnetic drive centrifugal pump
This is the pump that is installed in a horizontal orientation. This type of pump is easy to install and do maintenance since the parts are accessed easily. This pump is attached to the motor securely and safely. It has low headroom making it suitable for indoor applications where there is limited vertical space. However, the horizontal stainless steel magnetic drive centrifugal pump takes up a large footprint relative to other pumps. The net positive suction head of this pump is lower relative to that of vertical pump types hence limiting its capacity.
Figure: Horizontal stainless steel magnetic drive centrifugal pump.
Vertical stainless steel magnetic drive centrifugal pump
This is the type of pump that is designed for installation in a vertical orientation. It is best for applications that have a smaller footprint and smaller surface area since it takes up less amount of floor space. A vertical stainless steel magnetic drive centrifugal pump is suitable for use in both high pressure and high temperatures and its net positive suction head (NPSH) can be modified to fit a wide range of applications. However, this type of pump needs higher headroom making it difficult to install and maintain. This pump also has the challenge of balancing the long motor shaft to make it free from vibration and noise. However, it is best for serving in applications that have deep wells and pits.
Figure: Vertical stainless steel magnetic drive centrifugal pump.
Single-stage stainless steel magnetic drive centrifugal pump
This is the pump type designed with only one impeller. The impeller rotates on the pump shaft inside the casing. There are various types of these pumps that help to meet various requirements in different applications. This pump has a simple and compact structure, small volume, high speed, stable performance, high efficiency, lightweight, and large flow. It is also easy to repair and operate. It can be classified as either a vertical or horizontal pump. However, the pressure energy from this pump is lower relative to a multistage type of pump.
Figure: Single-stage stainless steel magnetic drive centrifugal pump.
Multistage stainless steel magnetic drive centrifugal pump
This is a pump designed with two or more impellers. The impellers are mounted on one or different shafts depending on the pump configuration. To enhance high outlet pressure, the impellers are joined in series while where high capacity is required, they are connected in parallel. Stainless steel magnetic drive centrifugal pump manufacturers design the pump such that one impeller discharge sucks the other until the fluid is fully exited to the discharge pipe. The pump is such that the more the number of impellers the more the pressure energy. This property makes the pump more powerful and suitable for high-head applications. However, for a very large pump, there is increased sensitivity of the impeller to external or natural vibrations.
Figure: Multistage stainless steel magnetic drive centrifugal pump.
Applications of stainless steel magnetic drive centrifugal pump
- These pumps are used to supply fluid in steam power plants since they can tolerate high temperatures and high pressure.
- They are used in the oil refineries industries to help transport petroleum products.
- Stainless steel magnetic drive centrifugal pumps are used in the transportation of chemicals.
- They are used to transport hazardous liquids.
- They are used in municipal, commercial, and household water supply.
- These pumps are used in food and beverage manufacturing to transport different products.
Advantages of stainless steel magnetic drive centrifugal pump
- These pumps are very strong due to the mechanical and thermal properties of stainless steel material.
- They can withstand both high temperatures and high pressure.
- They are durable.
- Stainless steel magnetic drive centrifugal pumps are versatile as they are suitable for use in various applications ranging from corrosives to non-corrosives.
- They are free from fluid leakage making them suitable for transporting hazardous and corrosive fluids.
- The repair and maintenance costs are low due to a low number of moving parts.
Disadvantages of stainless steel magnetic drive centrifugal pumps
- These pumps are best for transporting clean liquids that are free from solids.
- They are quite expensive relative to other pumps.
- The pump needs to be primed for it to operate.
Troubleshooting stainless steel magnetic drive centrifugal pumps
Pumping produces a lot of vibrations/noise
- Materials stuck on the impeller. Open the pump and clean off the materials.
- The motor and pipe are not tightly connected. Tighten the motor and the pipe to the torque recommended by the stainless steel magnetic drive centrifugal pump manufacturer.
Pump losses prime
- Suction line leakage. Repair or replace the suction line.
- Gas or air contained in the fluid. Remove all the air or gas.
- Leakage through the foot valve. Repair the foot valve.
- Foreign materials are loaded on the impeller. Remove the foreign materials.
- The suction pipe is not submerged sufficiently. Submerge the suction pipe properly.
Excessive power consumption
- High viscosity and specific gravity. Use the pump at the viscosity and specific gravity recommended by the stainless steel magnetic drive centrifugal pump manufacturer.
- Leakage through the suction line. Repair or replace the suction line as necessary.
- The valve is closed. Open the valve.
- The pump is not primed. Prime the pump.
- Higher head than expected. Use a higher-rated pump.
- Wrong motor rotation. Change the direction of motor rotation.
- Clogged suction line. Remove materials clogging the line.
- Clogged impeller. Open the pump as instructed by the stainless steel magnetic drive centrifugal pump manufacturer and remove clogging materials.
- The suction lift is too high. Reduce the suction lift or use the higher-rated pump.
- The impeller diameter is small. Replace the pump.
- Low motor speed. Use a higher-speed motor.
- Wrong motor direction of rotation. Change the direction of rotation.
Stainless steel magnetic drive centrifugal pumps use magnetic technology to operate. The pump is designed with two magnets that are the drive magnet and the inner magnet. The drive magnet is connected to the motor while the inner magnet is mounted inside the pump. As such, when the motor shaft starts spinning, it forces the inner magnet to rotate due to the magnetic field created by having the two magnets arranged with their poles opposite to each other. Rotation of the inner magnet forces the pump impeller to rotate at a high speed relative to the motor speed. With such rotation, a vacuum is created inside the pump and thus fluid is sucked into the pump. The fluid is then passed into the casing where its velocity is reduced and its pressure energy increased for transportation to the intended destination.
Stainless steel magnetic drive centrifugal pump manufacturers produce various pump types such as multistage pumps, single-stage pumps, horizontal pumps, vertical pumps, and submersible pumps among others. The applications of these pumps are fresh water supply, foods and beverages, oil refinery, steam power plants, water treatment, and chemicals among others. The advantages of using a stainless steel magnetic drive centrifugal pump are durable, versatile, and free from leakage, high strength, ability to withstand high temperatures, corrosion resistance, and has cheaper repair and maintenance.