How to quickly select a circulating water pump
The method of quickly selecting a circulating water pump mainly includes the following steps:
1. Clarify system requirements
Determine the flow requirements: The total flow of the circulating water pump should generally not be less than the total design flow of the pipe network. If there is a bypass pipe in the system, the flow through the bypass pipe must also be included in the total flow.
Determine the head requirements: Determine the head required for the circulating water pump according to the specific needs of the system.
Consider working pressure and temperature: Clarify the working pressure and allowable working temperature range required by the circulating water pump to ensure that the pump can operate stably in the system.
2. Understand the performance parameters of the circulating water pump
Rated flow and head: When selecting a circulating water pump, ensure that its rated flow and head can meet the needs of the system.
Efficiency: Give priority to circulating water pumps with higher efficiency to reduce operating costs.
Power: Select the appropriate power according to the power supply situation and energy consumption requirements of the system.
3. Consider the characteristics and applicability of the pump
Flow-head characteristic curve: Select a circulating water pump with a relatively flat flow-head characteristic curve near the working point, so that the head of the circulating water pump changes less when the hydraulic conditions of the pipe network change. Generally speaking, the characteristic curve of a single-stage water pump is relatively flat, which is suitable for use as a circulating water pump.
Pressure bearing capacity and temperature resistance: Ensure that the pressure bearing capacity and temperature resistance of the circulating water pump are consistent with the design parameters of the heating network. If installed on the water supply pipe of the heating network, a hot water circulating water pump with high temperature resistance must be selected.
4. Consider economy and reliability
Purchase cost: Select a reasonably priced circulating water pump on the premise of meeting the system requirements.
Operating cost: Consider the energy efficiency ratio and long-term operating cost of the circulating water pump, and select a product with higher energy efficiency.
Reliability: Select a circulating water pump with good quality and reliability to reduce the probability of failure, extend the life of the equipment, and reduce maintenance costs.
5. Specific selection suggestions
Model selection: According to the system requirements and the performance parameters of the circulating water pump, select a suitable model from the determined water pump series list. If there are multiple models that can meet the requirements, a trade-off analysis should be made to select a model with higher specific speed, smaller structural size, and lighter weight.
Number of units determined: The number of circulating water pumps shall not be less than two, one of which shall be a spare. When four or more water pumps are operated in parallel, no standby water pump is required. When centralized mass regulation is used, water pumps of the same model should be used in parallel.
Special requirements: For a single heat source heating system with multiple heat sources connected to the network or using central mass-flow regulation, the circulating water pump of the heat source should use a variable frequency speed regulation pump. For a mass regulation system that changes the flow in stages, in order to save electricity, it is advisable to use pump groups with different flow rates and heads.
6. Other considerations
Installation location: The location of the circulating water pump should take into account the overall layout of the system and the direction of fluid flow to ensure that the pump can work normally and reduce pipeline resistance.
Maintenance convenience: Select circulating water pump equipment that is easy to maintain and maintain to improve the reliability and service life of the equipment.
