Selecting the Right Split Case Pump for Your Application

Posted by angroup on December 5, 2023
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Split case pumps are a versatile type of centrifugal pump well-suited for a variety of industrial applications. When selecting a split case pump, it is important to consider the required flow rate, head pressure, viscosity and abrasiveness of the liquid, efficiency, and maintenance requirements for your particular application. Taking the time to properly match a split case pump to your needs will ensure reliable long-term operation and optimized energy efficiency. In this article, we will discuss the key factors to evaluate when selecting a split case pump for your system.

Determining Required Flow Rate and Head

The first step in choosing a split case pump is determining the flow rate and head requirements. Flow rate, measured in gallons per minute (GPM) or cubic meters per hour (m3/hr), indicates how much liquid needs to be pumped through the system. Head refers to the height the pump must raise the liquid or the pressure the pump must overcome to push the fluid through the system. You will need to consider maximum, minimum, and average flow demands and determine if the pump curves meet those needs. Consulting the system design schematics and speaking with the project engineers will provide the necessary flow rate and head details. Learn more Pump Terms

There are some general rules of thumb that can serve as a starting point for estimating pump requirements if specific details are unavailable. For clean water systems, a flow velocity of 1-3 meters/second in the pipes is typical. For liquids with higher viscosity, lower velocities around 0.5-1 m/s may be required. Pipeline friction losses of 5-15 meters of fluid head per 100 meters of pipe length can be assumed. Sum the static lift the fluid needs to be raised, the head loss through accessories like valves and filters, and the pipeline friction loss to determine the total system head.

double suction split case pump

Evaluating Liquid Properties

In addition to flow rate and head, the properties of the liquid being pumped significantly impact pump selection. Key considerations include:

Viscosity - Thicker, more viscous fluids will require more power to pump and special pump configurations to handle higher friction losses.

Abrasiveness - Abrasive liquids and slurries will require pumps with wear-resistant casings, impellers, and seals.

Temperature - Pumped fluid temperature changes viscosity and affects pump performance.

Solids - The maximum particle size and concentration of solids must be evaluated.

Corrosiveness - Corrosive liquids require casings, seals, and impellers made of compatible materials.

Proper pump sizing depends greatly on having accurate liquid property data. Without this information, unforeseen wear, clogging, and damage may occur. When in doubt, overestimate viscosity, abrasiveness, and solids content to provide a margin of safety.

Choosing Split Case Centrifugal Pump Size and Configuration

Split case pumps are available in a wide range of sizes and configurations to match various capacity and head requirements. Key options to evaluate include:

Impeller Diameter - Directly affects the maximum flow rate.

Number of Stages - Multiple impeller stages in series allows achieving higher head pressures

Materials of Construction - Needed to withstand fluid properties and environmental conditions. Common options include cast iron, stainless steel, duplex steel, and exotic alloys.

Seal Type - Influenced by liquid compatibility, temperature, and pressure. Mechanical seals, packing, and magnetically driven sealless pumps are among the major choices.

Bearing Type - Oil lubricated anti-friction bearings provide high efficiency. Water lubricated bearings suit clean water applications. Bushings or wet end bearings handle solids and high temperature applications.

Drive Type - Gear, v-belt, or direct driven by an electric motor or diesel engine.

diesel engine split case pump

Evaluating Pump Efficiency

The hydraulic efficiency of a pump significantly impacts the long-term operating costs in terms of power consumption to drive the unit. Lower efficiency pumps have higher energy losses due to friction, turbulence, and improper matching of the impellers and casings. Over time, a pump with just a few percentage points lower efficiency can waste substantial energy.

Pump efficiency curves are typically provided by the manufacturer based on testing. Make sure to evaluate the efficiency at the operating point coinciding with your flow rate and head requirements. In general, larger pumps tend to be more efficient, so choose the smallest size pump that meets your capacity needs while also providing suitable efficiency. Variable speed drives can also be used to optimize efficiency at various operating points. Installing flow meters can help diagnose pumping issues and track efficiency over time. Regular pump maintenance and inspection for wear and clearances out of spec can also prevent declining efficiency.

Considering Maintenance Requirements

Ease of maintenance is another important consideration for split case pump selection, especially for pumps handling abrasive or corrosive fluids. Pumps with front pull-out designs allow removing the impeller, seal, and bearing assembly without disturbing the piping connections. This simplifies maintenance work substantially. Standardizing on pumps from a single manufacturer or even a particular pump model when possible can allow keeping spare parts in inventory and simplify technician training.

When heavy solids or large debris is present in the pumped liquid, external flush and drain ports facilitate cleaning blockages. Some slurry pumps also include replaceable liner plates to protect the casings. Monitoring instrumentation such as vibration sensors, temperature gauges, and automated greasing systems can all substantially lower maintenance efforts. Ultimately, the costs of spare parts, downtime, and service work can far outweigh the initial purchase cost over the operating life of the pump. Carefully evaluating maintenance requirements will optimize lifecycle costs.

Conclusion

Selecting the right split case pump requires holistically evaluating flow rate, head, liquid properties, efficiency, and maintenance needs for your particular pumping application. Taking the time to gather system data, understand options, and properly size and configure the pump will pay dividends over the years of service. Partnering with an experienced pump supplier to select the right unit for your facility is highly recommended. With this guidance, we hope you are now well-prepared to choose a split case pump optimized for performance, efficiency, and reliability. Reach out with any additional questions we can address on your project requirements or pump selection process.

An Pump Machinery is a professional split case centrifugal pump manufacturer. If you require assistance with split case pumps, please contact us at anpump5@angroupcn.com or +86 15032857866; our technical sales engineers have considerable product knowledge and will be able to assist you.

Also see

Horizontal Split Case Pump Guide
Advantages of Split Case Pumps in Industrial Applications

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