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Comprehensive Guide to ISG Vertical vs ISW Horizontal Centrifugal Pumps

2025-10-17

Comprehensive Guide to ISG Vertical vs ISW Horizontal Centrifugal Pumps

In the field of industrial fluid transportation, ISG vertical centrifugal pumps and ISW horizontal centrifugal pumps have become mainstream choices for numerous application scenarios due to their unique structural advantages and precise scenario adaptability. However, when facing specific working conditions, achieving accurate model selection is a professional challenge. As the engineering team of Teffiko, we are well aware that there is no absolutely optimal pump model, only the most suitable solution. This article will conduct a comprehensive comparison between ISG and ISW centrifugal pumps from four major dimensions: structural design, performance characteristics, applicable scenarios, and installation & maintenance. It will also share Teffiko's practical experience in model selection to help you make informed decisions.

Table of Contents

1.Structural Design

2.Performance Characteristics

3.Applicable Scenarios

4.Installation and Maintenance

I. Structural Design Comparison between ISG Vertical Centrifugal Pumps and ISW Horizontal Centrifugal Pumps

The core difference between ISG vertical centrifugal pumps and ISW horizontal centrifugal pumps starts with their structural design. This directly determines their space occupation, installation method and pipeline adaptation logic, making it the primary factor to consider during model selection.horizontal centrifugal pump

(I) ISG Vertical Centrifugal Pump: Vertical Layout for Space Saving

The ISG vertical pump adopts an integrated vertical structure, with its pump shaft perpendicular to the ground. It has a relatively high overall height but a small floor area. Its water inlet and outlet are flexibly designed, allowing direct integration into the pipeline system without the need for an additional base. This makes it particularly suitable for narrow space scenarios, such as secondary water supply equipment rooms in high-rise buildings or compact production lines.

(II) ISW Horizontal Centrifugal Pump: Horizontal Layout for High Stability

The ISW horizontal pump features a structure where the motor and pump body are horizontally coaxial, with the pump shaft parallel to the ground and requiring fixation via a base. Its inlet and outlet are located on the same horizontal line, facilitating direct connection with horizontal pipelines and reducing resistance loss. This structure has a low center of gravity and ensures stable operation, making it suitable for scenarios with sufficient ground space, such as large workshops or municipal water plants, where maintenance operations are convenient.

II. Performance Characteristics Comparison: Energy Consumption, Head, and Cavitation Resistance

Beyond structural differences, the performance variations between the two directly impact operational efficiency and applicable working conditions. This is particularly evident in their adaptability regarding energy consumption, head range, and cavitation resistance.

(I) Energy Consumption and Efficiency

In terms of hydraulic efficiency, both ISG and ISW centrifugal pumps adopt advanced hydraulic model designs. After optimizing the impeller flow channel, their efficiencies under rated working conditions are relatively close, typically ranging from 75% to 85%. However, differences emerge in variable-load operation scenarios:


  • The ISW horizontal centrifugal pump has a gentler pump body flow channel, leading to a smaller efficiency drop when operating outside the rated flow. It is more suitable for scenarios with large flow fluctuations.
  • The ISG vertical centrifugal pump maintains stable efficiency under rated flow but experiences faster efficiency attenuation when flow fluctuates. It is more suitable for scenarios with constant flow requirements.


In terms of energy consumption:


  • The ISG pump consumes less energy under low-flow, high-head working conditions.
  • The ISW pump delivers better energy efficiency in high-flow, low-head applications.


(II) Head Range


  • The head range of the ISG vertical centrifugal pump is usually 5m-125m, making it more proficient in meeting "high-head, low-flow" transportation needs. Its vertical-structured pump shaft bears force more evenly; when operating at high head, the centrifugal force transmission of the impeller is more stable, and shaft deviation caused by excessive pressure is less likely to occur. Therefore, it is often used in scenarios such as high-rise building water supply and boiler feed water.
  • The head range of the ISW horizontal centrifugal pump focuses more on "medium-low head, high flow," generally ranging from 3m-80m. Its horizontal structure can better adapt to the stable transportation of large-flow media and avoid excessive axial force caused by high head. It is suitable for scenarios with low head requirements but high flow demands, such as municipal pipe network water transmission, industrial circulating water, and agricultural irrigation.

vertical centrifugal pump

(III) Cavitation Resistance: ISW Has the Edge

The net positive suction head (NPSH) of the ISW horizontal pump is usually 0.5m-1.5m lower than that of the ISG pump. Its suction port design is more optimized, making it less prone to cavitation when transporting easily vaporized media or under high suction resistance. The ISG vertical pump, on the other hand, is more suitable for occasions with good suction conditions and short pipelines.

III. Applicable Scenarios Comparison: On-demand Matching is the Key

(I) ISG Vertical Centrifugal Pump: First Choice for Narrow-space and High-head Scenarios


  • Secondary water supply in high-rise buildings: High-rise residents require relatively high water pressure, and equipment rooms are usually located on the roof or in the basement with narrow space. The ISG vertical centrifugal pump perfectly fits this scenario with its advantages of small floor area and high head.
  • Supporting small industrial equipment: Such as cooling systems for CNC machine tools and feed water systems for small boilers. These scenarios have stable flow demand and limited installation space, and the ISG pump can be integrated into the pipeline to save space.
  • Water circulation in commercial premises: Including cooling water circulation for central air conditioners in hotels and fire water supply systems in shopping malls. The vertical structure of the ISG pump facilitates connection with pipelines in the ceiling or at the corner, without affecting the indoor layout.


(II) ISW Horizontal Centrifugal Pump: Main Option for Large-space and High-flow Scenarios


  • Municipal water treatment: Including reclaimed water reuse in sewage treatment plants and pipe network transmission in waterworks. These scenarios have large flow demand and sufficient ground space, and the horizontal layout of the ISW pump enables batch installation and centralized maintenance.
  • Large-scale industrial production: Such as raw material transportation in chemical enterprises and cooling circulating water systems in metallurgical plants. These scenarios have large flow fluctuations and require cavitation resistance, and the ISW pump has better stability and adaptability to meet these needs.
  • Agricultural and civil irrigation: Including farmland irrigation and water change in large fish ponds. These scenarios have low head demand but large flow demand, and the ISW pump’s characteristics of low energy consumption and easy maintenance can reduce long-term operating costs.


IV. Installation and Maintenance Comparison

Installation difficulty and maintenance costs are factors that cannot be ignored during long-term use. The differences between the two in this dimension directly affect the operational efficiency in the later stage.

(I) Installation


  • For the ISG vertical centrifugal pump: No separate base is required for installation. It only needs to connect the pump body flange to the pipeline flange and fix the pump feet with expansion bolts. One person can complete the installation of one piece of equipment within half a day, making it especially suitable for renovation projects of existing sites. However, it should be noted that its vertical structure has high requirements for installation perpendicularity. If the pump shaft tilt exceeds 0.1mm/m, it will easily lead to accelerated bearing wear.
  • For the ISW horizontal centrifugal pump: It is necessary to first pour a concrete base or install a steel bracket to ensure that the base level error does not exceed 0.2mm/m. Then fix the pump body on the base and finally connect the pipeline. The installation cycle is about 1-2 days, making it more suitable for the early planning of new construction projects. However, its horizontal layout has a higher fault tolerance for the flatness of the foundation, and slight ground settlement will not easily affect the operation of the equipment.


(II) Maintenance

The ISW horizontal centrifugal pump is more convenient for maintenance: Due to the horizontal distribution of the motor and the pump body, during disassembly, it only needs to remove the coupling shield and loosen the connecting bolts to separate the motor from the pump body. When replacing vulnerable parts such as impellers and seals, there is no need to move the pipeline. Maintenance personnel can operate on the ground, which is highly safe. For example, when the seal leaks, maintenance personnel do not need to climb high and can complete the replacement within 1-2 hours.

For the ISG vertical centrifugal pump, since the motor is located at the top, during maintenance, it is necessary to first remove the motor wiring and fixing bolts, and lift the motor to access the internal components of the pump body. If it is installed in a narrow space or a high-rise equipment room, it is necessary to use a crane or lifting equipment, resulting in a long maintenance cycle and high cost. Therefore, for scenarios with high requirements for maintenance convenience (such as unattended pump stations), the ISW horizontal centrifugal pump is more recommended.

V. Selection Summary: 3-Step Quick Judgment


  • Check the space: Choose the ISG vertical pump for narrow spaces, and the ISW horizontal pump for sufficient ground space.
  • Check the working conditions: Choose the ISG pump for high-head and low-flow requirements, and the ISW pump for medium-low head and high-flow requirements.
  • Check the maintenance needs: Choose the ISW pump for unattended operation and convenient maintenance; choose the ISG pump for scenarios with long maintenance intervals and limited space.


Conclusion

ISG vertical centrifugal pumps and ISW horizontal centrifugal pumps each have their own advantages, and the core of selection lies in "adaptation"—aligning with your space, working conditions, and maintenance requirements. If you are still unsure about selecting the optimal pump model for your specific working conditions, Teffiko’s professional team can provide free selection consultation. We have rich application experience and can recommend the most suitable and efficient solution based on your specific parameters (such as flow rate, head, medium characteristics, installation environment, etc.), ensuring stable and energy-efficient operation of your fluid system.



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