Horizontal centrifugal circulating water pumps are a crucial type of circulating water pumps designed to handle both hot and normal temperature water. These pumps are typically installed at heating stations, heat sources, or cold sources. In the closed - loop systems of heating and air - conditioning, they play a vital role in ensuring the continuous circulation of water, overcoming the resistance within the loop without being affected by the building's height. Understanding their working principles and characteristics is essential for optimizing the performance of various fluid transfer applications.

Type of horizontal centrifugal circulating water pump

There are basically two types of cold and hot water circulating water pumps. One is the hot water circulating water pump that transports hot water or high temperature water above 80 ℃ as a closed-loop circulation; The other is the circulating water pump that transports the normal temperature liquid and the medium below 80 ℃. We also call it the cold water circulating water pump or the low temperature coolant circulating water pump.

1. S - type Horizontal Centrifugal Double - suction circulating water pump: Features and Applications.

The S - type horizontal centrifugal double - suction circulating water pump is a remarkable innovation in fluid transfer technology. Its unique design, with the suction inlet and discharge outlet both below the pump's axis and in a horizontal direction perpendicular to it, offers several advantages. It is highly suitable for a wide range of applications, including factories, mines, urban water supply, power stations, tap water systems, and farmland irrigation. The convenience of maintenance is a standout feature, as it allows for easy access to internal components without the need to disassemble the inlet and outlet pipes and motors. This not only saves time and effort but also reduces downtime. In terms of performance, it is energy - efficient and operates with high efficiency. Comprising components such as the pump body, pump cover, shaft, impeller, sealing ring, shaft sleeve, and bearing parts, its modular design enables easy maintenance and replacement. Moreover, it can be customized to handle different types of liquids, from clean water to sediment - laden or corrosive liquids, by adjusting the pump structure and material, making it a versatile choice for various industries.

2. DG Horizontal Centrifugal High - pressure High - temperature Circulating Water Pump: Characteristics and Suitability.

The DG horizontal centrifugal high - pressure high - temperature circulating water pump is engineered to meet the demanding requirements of specific applications. It is designed to transport clean water or liquids with similar physical and chemical properties, making it an ideal choice for medium and low pressure boiler water supply, sub - high pressure boiler systems, and high - pressure water supply and drainage in industrial and urban settings. With a transmission medium temperature range of - 20 ℃~150 ℃ and an allowable inlet pressure of less than 0.6MPa, it can handle a wide variety of operating conditions. Adopting the state - recommended hydraulic model of high - efficiency energy - saving products, it exhibits excellent performance in terms of efficiency, a wide performance range, and safe and stable operation. The vertically upward inlet and outlet, along with the bolt - connected pump shell parts, enhance its structural integrity and ease of installation and maintenance. The ability to select the pump stage based on the required pump head further adds to its flexibility and adaptability in different systems.

Selection of circulating water pump

In the case of cold and hot water circulating water pump, the following requirements shall be met:

(1) Flow and Head Requirements. The first and foremost consideration in selecting a cold and hot water circulating water pump is to ensure that its total flow meets or exceeds the total design flow of the pipe network. This includes accounting for any additional flow through bypass pipes, if present. The flow - head characteristic curve of the pump is also crucial. A relatively flat curve near the working point is desirable as it minimizes the impact of network hydraulic changes on the pump's head. Single - stage water pumps are often preferred due to their typically flatter characteristic curves, which help maintain stable operation. For example, in a large commercial building's heating system, accurately matching the pump's flow and head to the network requirements ensures efficient heat distribution and minimizes energy waste.

(2) Pressure and Temperature Compatibility. The circulating water pump must be capable of withstanding the pressure and temperature conditions of the heating network. Most pumps are installed on the return pipe, where the allowable working temperature is not lower than 80 ℃. However, if installed on the water supply pipe, a high - temperature resistant hot water circulating water pump is essential. This compatibility ensures the pump's longevity and reliable performance. In industrial boiler systems, where high temperatures and pressures are involved, selecting a pump with appropriate pressure and temperature ratings is critical to prevent premature failure and ensure system safety.

(3) Number and Regulation of Pumps. The determination of the number of circulating water pumps depends on the heating regulation mode of the system. At least two pumps are required, with one serving as a standby. In some cases, when four or more pumps operate in parallel, a standby pump may not be necessary. When centralized mass regulation is employed, using pumps of the same model in parallel is recommended for better control and performance. Additionally, in systems with multi - heat source networking or central mass - flow regulation, variable frequency speed pumps are often the best choice as they can adjust the flow according to the actual demand, saving energy. For instance, in a district heating system with multiple heat sources, variable frequency pumps enable efficient heat distribution and energy optimization.

(4) Special Considerations for Different Systems. In hot water heating systems with staged flow quality regulation, different pump sets with varying flow and head capabilities should be selected to match the different stages and save energy. For systems with hot water supply heat load, where the non - heating period flow is significantly lower than the heating period, adding a dedicated circulating water pump for the special hot water load can improve system efficiency. Moreover, when multiple pumps operate in parallel, accurately drawing the hydraulic characteristic curves of the pumps and the heat supply network is essential for determining the optimal working point and selecting the most suitable pumps. This detailed analysis helps ensure the overall performance and energy efficiency of the heating system.

In conclusion, horizontal centrifugal circulating water pumps are essential components in heating and cooling systems, with different types offering unique features and capabilities. The proper selection of these pumps, considering factors such as flow, head, pressure, temperature, and system requirements, is crucial for ensuring efficient and reliable operation. As technology advances and energy efficiency becomes increasingly important, staying informed about the latest developments in pump design and selection criteria will help engineers and system operators make optimal decisions, enhancing the performance and sustainability of fluid transfer systems.