The proportion of circulating pump in the heating system, whether it is capacity or the number of devices are great, and the problems in operation are more. Therefore, the correct choice, rational use and management, to ensure normal heating and improve economic efficiency is very important. That the principle of circulating pump selection and what are the considerations? Circulating water pump 1, the principle of circulating water pump selection 1. The selected circulating pump should meet the maximum flow and lift required in the system, and make the best conditions for circulating pump, as close as possible to the actual system operating point, and Long-term operation in the high-efficiency zone to improve the long-term operation of circulating pump economy. 2. Strive to choose a simple structure, small size, light weight, relatively high efficiency circulating pump. 3. Strive to run safe, reliable, stable, small vibration, low noise, good anti-cavitation performance. 4. Select for large flow changes and head changes little water pump, G-H characteristic curve tends to be flat pump. Second, the selection of circulating pump considerations 1. Circulation pump capacity to determine the circulating pump flow is calculated according to the heating of outdoor users calculate the sum of heat consumption, and in the entire heating period to reach the outdoor temperature heating calculation of outdoor temperature The time is short, which makes the pump flow is large for most of the time. Before choosing the circulating pump, we must first determine the regulation of the heat network system, and then determine the circulating pump flow according to the system regulation. For the heating system with centralized quality control, the total flow of circulating water pump should not be lower than the total design flow of the system. The lift should not be less than the total pressure loss of the system, that is, the flow of the circulating water pump. The lift need not Plus the amount of wealth. Focus on the quality of the heating system, most of them are small temperature difference, high flow conditions operating conditions, it is economically unreasonable. The use of phased flow control to adjust the quality of the way the operation, can save a lot of water circulation pump power consumption. The heating period according to the level of outdoor temperature is divided into several stages, when the outdoor temperature is higher circulation pump with a small flow, low outdoor temperature open the pump when the flow. Each stage to maintain the same traffic to meet the heating needs. Heat exchange station can be installed with different flow pumps, installation of a 100% flow and two 50% circulation flow pump, according to the outdoor temperature of the pump adjustment, the other with frequency control, the pump soft start, reduce the starting current, Enhance the service life of the pump, and at any time according to the changes in the weather, different periods of the heating curve to regulate the flow, save energy and meet the requirements of the recycled water of different periods to achieve energy-saving effect. 2. The boiler body flow resistance Hot water boiler as the hot water heating system, the internal resistance of the heat source is mainly the boiler water flow resistance, this value should be provided by the boiler manufacturer. When the selected boiler cooling operation below the rated supply and return water temperature, such as 95/70 degree low temperature water boiler running at 60/50 degrees, we must consider when the same heat is supplied, the actual circulating water is greater than the rated circulating water , The boiler water flow resistance increases. Due to the limitations of the boiler series, the common boiler feed and return water temperature is 95 / 70e boiler temperature drop operation, at this time reduce the temperature difference, which can calculate the flow and flow resistance. Visible due to the cooling operation of the boiler to increase the resistance should be caused enough attention to the designer, so as not to circulate the pump head is not enough, resulting in insufficient user traffic. If you increase the pump head, will result in waste of electricity, it is recommended to choose the right temperature of the boiler, boiler boiler or require manufacturers to adjust the actual temperature structure. 3. The method of choice Use the "pump performance table" to select the pump, the current market pump models, a wide range of pumps suitable for heating systems have single-stage single-suction or single-stage double suction vertical pipeline pump, single-stage single suction horizontal centrifugal Pump, direct-coupled single-stage single-suction horizontal centrifugal pump, open-shaft single-stage double-suction horizontal centrifugal pump and single-stage double-suction open volute centrifugal pump. You can choose according to the following steps: â‘ The original calculated flow and lift can no longer be attached. â‘¡ in a given pump series of tables to find a pump of the type, find the flow and lift and "pump performance" listed representative (usually in the middle) of the flow and lift the same, or though inconsistent, but in Up and down within two working lines. If there are more than two types of pumps to meet the requirements, then trade-off analysis, usually one of the higher speed than the speed (ns), the structure of the small size, light weight pump. â‘¢ After the specific pump model has been selected, it is necessary to check the operation of the pump when it is running in the system and observe its range of flow and head changes whether it is working in an efficient area. If the operating conditions point away from the high efficiency zone is far, then the pump in the system of poor economic work, the best alternative. 4. Pump compressive strength of hot water circulating pump When the water temperature is less than 80 degrees, the circulating water is not large, you can choose IS-type pump; when the circulating flow is larger, optional S-type double suction pump; water temperature higher or static pressure Value of the occasion, the choice of R-type heat pump. Pump manufacturing different materials, its pressure capacity is not the same. Also pay attention to pump inlet pressure and outlet pressure when choosing a pump. Pump outlet pressure is equal to the pump inlet pressure plus pump head, is the pump maximum working pressure. When the fixed pressure point is set at the inlet of the circulating pump, the pump outlet pressure is greater than the head of the pump, that is, the pressure of the fixed pressure point plus the pump head, if the working pressure exceeds the compressive strength of the pump, the pump body may be fractured, and some pump samples Pump pressure is given, which is easy to overlook the problem designer must pay attention to, design or order should provide pump working pressure values. Further Reading: pump valve pipe fittings Exhibition Water Expo Xiamen exhibition of marine equipment Internet + Forum Yiwu Fair 2016 exhibition mold top ten brands of the Internet information industry (Xiamen) Technology Co., Ltd. Author: Asian pumps Network Editor: Yao Xiaoxia (QQ / WeChat:) http://beng.liuti.cn/ (Service Hotline:)
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