Discover the differences between single suction and double suction centrifugal pumps. Learn their applications, benefits, and performance characteristics.
Single suction pumps and double suction pumps are two types of centrifugal pumps. The main difference between them is the number of suction inlets they have. Single suction pumps have only one suction inlet, while double suction pumps have two.
The double suction design allows for a more balanced hydraulic load, which can result in reduced axial thrust and longer bearing life. As a result, double suction pumps are often used in high-flow applications, such as in water supply and circulation systems. In contrast, single suction pumps are commonly used in low to medium-flow applications, such as HVAC and industrial processes.
Types of Pumps
Are you looking to purchase a new concrete pump but need clarification about the difference between a single and double suction pump? Look no further! In this article, we’ll provide an in-depth analysis of both types of pumps, including their working principles, advantages, disadvantages, and pricing.
In this article, you’ll better understand which pump type best suits your needs.
Double Suction Pump
The double-suction pump utilizes a pair of impellers arranged in a back-to-back configuration, and the water discharged from the impeller is directed into a spiral casing. Owing to its superior design, this pump is extensively employed in various engineering applications due to its exceptional flow rate and high head.
With two suction chambers, it is commonly believed that one of the chambers serves as the inlet while the other functions as the outlet. The pump’s suction and inlet are perpendicular to the axis’s lower section, primarily determined by the impeller’s orientation.
One significant benefit of the double-suction centrifugal pump is its reduced susceptibility to cavitation at the same rate and flow due to a reduction in the inlet flow.
Single Suction Pump
The suspended single suction pump employs horizontal and axial suction and upward and radial discharge. As a result, the rotor components can be removed for maintenance without requiring dismantling the inlet and outlet pipelines.
The pump is linked to the motor using a standard or extended elastic coupling, and the pump shaft seal is secured using soft packing. A single row of radial ball bearings lubricated with oil is used in the bearing. The motor rotates in a normal motion when viewed from the motor end.
Functional Principle
Upon starting a single suction pump, the shaft drives the impeller to spin at a high velocity, inducing the liquid that had already filled the spaces between the blades to rotate. The centrifugal force causes the liquid to move radially from the impeller’s center to its periphery, where it gains energy and experiences an increase in flow rate due to the accompanying increase in static pressure energy.
After exiting the impeller and entering the pump casing, the liquid slows down due to the gradual widening of the flow channel. This converts kinetic energy into static pressure energy before it flows tangentially into the discharge pipeline. The spiral pump casing collects the liquid that exits the impeller while also functioning as an energy conversion device.
A low-pressure zone develops in the center as the liquid is ejected from the impeller’s center to the exterior. The real difference in potential energy between the liquid level in the storage tank and the impeller’s center draws the liquid into the impeller’s center.
The impeller’s constant operation results in a continuous inflow and outflow of liquid, with the mechanical energy gained by the liquid in the industrial centrifugal pump manifesting as an improvement in static pressure energy.
Distinction Between Single Suction Pump and Double Suction Pump
Diverse Inlet
The diverse inlet design of double suction pumps allows for the smooth conveyance of large flows and ensures stable operation. In contrast, a single suction pump with a high flow requirement should have a large inlet and outlet diameter.
Additionally, double suction pumps have superior resistance to cavitation due to the symmetrical impeller action, which creates a more stable hydraulic balance. However, this enhanced performance comes at a higher price than single suction pumps. Therefore, selecting a suitable pump type depends on the user’s specific operational needs and conditions.
Variation in Flow
When it comes to conveying large amounts of fluid, industrial double suction pumps are a better choice as they require a stable operation. However, if the flow requirements are high, single suction pumps should have a large inlet and outlet diameter.
Resistance to Cavitation
A double-suction pump is more resistant to cavitation than a single-suction pump. An axial single suction pump produces less stable hydraulic balance than a double suction pump due to the symmetrical impeller movement on both ends of the latter. Additionally, since the medium’s low flow rate, the impeller is less susceptible to cavitation.
Differentiation in Price
In terms of cost, double-suction pumps are generally more pricey than single-suction pumps. Even though single-suction pumps are less expensive and can be used in multiple applications, double-suction pumps have many advantages. Users should consider their operating conditions to determine the most suitable option.
Conclusion
Single and double suction pumps differ in inflow, flow rate, cavitation resistance, and price. In addition, single-suction pumps have an impeller filled with water at one end, while double-suction pumps have two inlets. As a result, double suction pumps are better for large flows, while single suction pumps need a large inlet and outlet diameter and stable operation.
Double suction pumps are more resistant to cavitation due to their symmetrical impeller action but are also more expensive. The choice between the two types of pumps depends on the user’s specific needs and operating conditions.
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