Understanding the Basics: A Guide to Split Case Pumps

Split case pumps are a type of centrifugal pump that consist of a split housing enclosing an impeller. They are a versatile type of pump used in a variety of industrial applications for moving water and other low to medium viscosity fluids. In this article, we will provide an in-depth guide on split case pumps, including how they work, their components, types, applications, and basic maintenance.

How Split Case Pumps Work

Split case pumps are kinetic pumps, meaning they add energy to a fluid by increasing its velocity. The pump uses an electric motor to turn an impeller within the pump casing. As the fluid enters the center of the impeller, it gets accelerated outwards by centrifugal force into the outer housing. This kinetic energy gets converted to pressure energy as the fluid slows down in the outer chamber of the housing.

The fluid gets directed from the high pressure side of the impeller into a discharge nozzle where it exits the pump. The rotational motion of the impeller creates suction, continually drawing more fluid into the center while discharging pressurized flow out. This create a continuous flow of fluid through the pump casing.

Main Components

Split case pumps consist of three main components:

• Impeller: The impeller is a rotating disk with vanes that accelerates the fluid. It is connected directly to the pump shaft and electric motor. Different types of impellers are used based on the specific gravity and viscosity of fluids. Closed impellers are most common in split case pumps for handling water-like fluids.
• Casing: The casing (housing) consists of two separate chambers, suction and discharge. The chambers fully enclose the impeller and provide pathways for the fluid to enter and exit. Casings are split axially (horizontally) so impellers can be accessed and maintained without disturbing piping. Casings are made of cast iron, stainless steel or bronze.
• Shaft & Bearings: The shaft transmits rotation from the motor to turn the impeller. Bearings enable smooth shaft rotation and support radial forces. Split case pumps use bushings, ball bearings or oil-lubricated journal bearings. Larger pumps may require packing glands to seal and lubricate shafts.

Types of Split Case Pumps

There are two main types of split case pump configurations - horizontal shaft, and vertical shaft.

• Horizontal split case pump: Fluid enters impeller from both sides with 2 suction nozzles and casing split across the shaft diameter instead of horizontally. Balances axial thrust allowing higher capacity pumping.

• Vertical split case pump: Pump shaft is oriented vertically with pump ends enclosing impeller from top and bottom. Handles high flows while taking up less floor space by extending vertically. Requires additional bearings to handle axial loads.

Typical Applications

Split case pumps are extremely versatile and used widely in industrial plants, factories, commercial buildings, and municipal water supply systems. Typical applications include:

• Water supply: Boosting pressure in distribution systems, wells, filtration plants.
• Cooling water: Recirculating chilled or tower water in HVAC and process systems.
• Wastewater: Handling raw sewage, effluent or slurries.
• Fire suppression: Pressurizing sprinkler systems.
• Boiler feedwater: Feeding water to utility and heating boiler systems.
• Chemical supply: Transferring paints, solvents, acids and corrosive chemicals.
• Condensate return: Returning trapped steam condensate in lines, condensers, and heat exchangers.

Split case pumps are well suited for reliably moving medium viscosity water-like fluids in medium flow, medium head applications, at moderate temperatures and low to moderate pressures. They can handle water, oils, brines and various industrial liquids.

Pump Sizing & Selection

Properly sizing and selecting a split case pump requires determining the flow rate, head pressure, fluid properties, and operating conditions. Key steps include:

• Determine system requirements - desired flow rate, head, fluid type and properties, temperature and suction/discharge pressures.
• Choose a pump size with sufficient flow, head and pressures - oversize safety factors are commonly added.
• Select pump configuration - end suction, double suction or vertical shaft.
• Choose suitable materials for the casing, impeller, seals, and shaft based on fluid properties and temperature.
• Specify driver type and power rating - motors need ability to overcome head pressure to desired flow rate.
• Consider auxiliary options - baseplates, couplings, controls, and sensors.

Working with a reputable manufacturer(AN PUMP®) will ensure you obtain a reliable pump system sized and selected properly for your specific application. Also See How to Properly Size a Split Case Pump for Your System

Installation & Maintenance

Properly installing split case pumps helps ensure smooth operation while routine maintenance keeps them operating optimally over their service lifetime. Here are some key guidelines:

• Install pumps as close as possible to supply tanks / suction inlet source to maximize suction head.
• Ensure inlet feed pipes are one or two sizes larger than suction diameter to reduce friction losses.
• Verify that pump shaft rotation matches the direction indicated by the arrow mark on the casing.
• Install packing glands evenly without overtightening to prevent shaft wear.
• Periodically check / replace worn wear rings which allow fluid leakage from discharge back to suction side.
• Inspect impeller clearance and replace shims to meet specifications as impellers wear over time.
• Check bearing lubricant levels monthly and lubricate as needed. Inspect for wear and replace if necessary.
• Verify sealing points and repack / replace seals if chronic fluid leakage occurs.

Conclusion

We have covered the inner workings, components, types, applications, sizing calculations and maintenance considerations for split case pumps. With their durable cast metal construction and versatile configurations, split case pumps provide reliable service for challenging industrial pumping environments across all types of facilities. Following proper installation, sizing and routine maintenance procedures will enable split case pumps to provide many years of optimal service with low lifecycle costs. Reach out to pump manufacturers if you need any assistance specifying an appropriately sized system.

An Pump is a professional split case pump manufacturer. If you require assistance with split casing pump, 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.