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Understanding the QY Series Oil-Immersed Submersible Pump
The QY series represents a widely adopted design in the submersible pump market. These pumps integrate a water pump, mechanical seals, and an electric motor into a single, compact unit. The pump section is located at the upper portion of the assembly, while the three-phase asynchronous motor resides in the lower portion, filled with oil for cooling and insulation. A mechanical seal between the pump and motor sections provides dynamic sealing, while “O” ring rubber seals at static joints prevent leakage.
The QY200-4 designation indicates a pump with a rated flow of 200 m³/h and a rated head of 4 meters. This high-flow, low-head characteristic makes these pumps ideal for applications requiring large volumes of water transfer, such as flood irrigation, water transfer projects, and dewatering applications. The model is typically offered with different power ratings, including 4KW, 5.5KW, and 7.5KW versions, to suit varying operational requirements.
The Critical Role of the Impeller
The impeller is the rotating component that converts mechanical energy from the motor into kinetic energy in the fluid. As the motor shaft turns the impeller, the blades—which feature a three-dimensional twisted ruled surface geometry—accelerate the water outward, generating flow and pressure. In QY series pumps, the impeller can be of centrifugal, mixed-flow, or axial-flow design, with the choice depending on the specific flow and head requirements.
Over time, impellers are subject to wear from abrasion, corrosion, and erosion, particularly when pumping water containing fine sand or other suspended solids. Even in applications where the medium is clean water, continuous operation eventually takes its toll on the impeller’s efficiency. Replacing a worn impeller is often a far more cost-effective solution than replacing the entire pump unit.
Product Specifications: 5.5KW and 7.5KW Impellers
Our replacement impellers are manufactured to meet the dimensional and performance specifications required by QY series pumps, including the widely used QY200-4 model.
Size Options
We offer impellers in two common sizes to match different pump configurations:
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6-inch impellers: Suitable for smaller pump frames and applications with moderate flow requirements.
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8-inch impellers: Designed for larger pumps, including those with higher power ratings, which can accommodate larger diameter components to move greater volumes of water.
Power Rating Compatibility
Our impellers are available for pumps with 5.5KW and 7.5KW motor ratings. It is important to match the impeller’s design to the motor’s power output—an impeller that is too large for the motor can lead to overload conditions, while one that is too small will result in underperformance. The 5.5KW and 7.5KW options correspond to the common motor sizes used in medium-duty agricultural, municipal, and industrial pumping applications. In the international market, 5.5KW is approximately equivalent to 7.5 horsepower, and 7.5KW is approximately 10 horsepower.
Material and Construction
Our impellers are manufactured from cast iron (grey cast iron), a material that provides an excellent balance of strength, wear resistance, and cost-effectiveness for clean water applications. Cast iron offers good casting characteristics, allowing for the precise geometry required for efficient pump performance. For applications with more demanding requirements—such as pumping water with higher corrosive potential—we can also supply impellers in alternative materials, including bronze and stainless steel (SS304, SS316).
Applications and Compatibility
The QY200-4 pump, and by extension, the impellers we supply, are designed for pumping clean water with the following characteristics:
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Medium temperature: Not exceeding 40°C
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pH range: 6.5 to 8.5
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Solid content: Less than 0.1% by volume, with particle size not exceeding 0.2mm
Typical applications include:
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Agricultural Irrigation: Large-scale farm sprinkler and drip irrigation systems, rice paddy flooding, and orchard watering.
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Mine Drainage: Dewatering operations in mines and quarries.
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Municipal Water Supply: Water transfer, supplementary supply, and emergency water provision.
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Construction Dewatering: Removing groundwater from construction pits and foundations.
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Water Treatment: Pumping water in treatment plants and water features.
How to Select the Correct Impeller
When ordering replacement impellers, please confirm the following details to ensure correct fitment:
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Pump Model and Manufacturer: The QY series is produced by various manufacturers, and there can be slight variations. Please confirm that your pump is a standard QY200-4 or compatible model.
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Motor Power: Clearly indicate whether your pump is 5.5KW or 7.5KW.
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Impeller Diameter: Choose between 6-inch and 8-inch sizes.
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Shaft Bore and Keyway Dimensions: Where possible, provide the diameter and keyway size of the pump shaft to ensure a proper fit on the motor shaft.
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Material Requirement: Specify if you require cast iron, bronze, or stainless steel.
Quality Assurance and Sourcing
As a dedicated supplier with a focus on pump accessories, we understand the importance of delivering parts that not only fit but also perform. Each impeller undergoes dimensional inspection to ensure it meets the required specifications. We work with reliable manufacturing partners to ensure consistent quality and material integrity.
While we are a supplier, not a manufacturer, our close relationships with production facilities allow us to maintain strict quality control and offer competitive pricing. We can support both small-quantity orders for maintenance purposes and larger bulk orders for distributors.
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