A net circulation pump selection and use

With the development of domestic economy, people pay more and more attention to energy-saving and emission reduction, environmental protection and livelihood issues, and the manpower and resources involved are also increasing. As the heating of urban residents involves the above problems at the same time, Which has also become the top priority. As for the main equipment in the heating system pumps, but also put forward higher requirements. A network of circulation pump selection and use 1, the introduction of central heating system In China, Qinling Mountains Huaihe north of the town in the implementation of central heating in winter to spend the cold winter. Heating area accounts for about 2/3 of the territory area. Created in the beginning, the majority of cities and towns using small regional boiler room, which makes the boiler room small and scattered, utilization is not high, the thermal efficiency is mostly lower than 60%, resulting in many northern cities a winter haze days are very large, to Resident life caused a lot of trouble. With the development of economy in our country, the heat network heating system as urban infrastructure has developed rapidly. The system diagram is shown below. This heating system is to ban multiple small boiler rooms, to place the heating heat source in one place, or to use cogeneration. This situation not only helps to save energy, concentrate heat, but also help to control the environment. At present, more than 40% of the cities have built centralized heating facilities in the country, but there is also a tendency of increasing year by year. A network is the total pipeline network of hot water coming out of the heat supply station, usually only to the heat exchange station, not directly heating the user. Hot water network design has reached the maximum temperature of about 150 ℃, the pressure reached 2.5MPa; second network refers to the local heat exchange station and a network of heat exchange, direct connection with hot users of hot water pipe. The maximum temperature of the hot water network reaches about 90 ℃, the pressure reaches 1.6MPa A network circulating pump in the heating system, the proportion of both capacity and equipment are large, the problems in operation are more features of a network As a result, the requirements for the heating network circulating pump are very special. Therefore, it is very important to select, use and manage properly to ensure normal heating and improve economic efficiency. 2 a network circulation pump structural characteristics 2.1 pump structure as the center of support, this structure can reduce deformation caused by thermal expansion and contraction caused by shaft changes, so that the pump run more balanced. 2.2 pump shell made of high strength steel. 2.3 machine seal cooling proposal is plan23 2.4 pump bearings with thin oil lubrication. 3 primary circulation pump selection principle Circulation pump selected should meet the maximum flow and lift required in the system at the same time make the best working conditions circulating pump as close as possible to the actual system operating point, High-efficiency zone operation, in order to improve the long-term operation of circulating pump economy. 3.1 strive to choose a simple structure, small size, light weight, relatively high efficiency circulating pump. 3.2 strive to run safe, reliable, stable, small vibration, low noise, good cavitation resistance. 3.3 Select for large flow changes and head changes little water pump, GH characteristic curve tends to be flat pump. 4 a network circulation pump use precautions 4.1 Before turning on the pump, be sure to open the pump seal and bearing cooling system. 4.2 A network of medium temperature up to 150 ℃, the pump must be used before running the pump to preheat the temperature rise evenly, and every 10 minutes a half-turn plate, and open the inlet valve and exhaust valve , The exhaust gas pump, preheated to the required temperature and then close the exhaust valve. 4.3, After the pump starts to run, slowly open the outlet valve to the pump rated point, observe the pump operation, vibration and noise requirements are within the standard. In case of abnormal circumstances should be promptly shut down inspection. 4.4, the pump is running, pay close attention to the detection of bearing operating temperature, the sliding bearing is less than 75 ℃, the rolling bearing is less than 85 ℃, such as the bearing temperature exceeds the standard, you need to immediately check the cause and analyze and deal with. 4.5, turn off the pump outlet valve, only to confirm the media temperature is below 80 ℃ below, to close the seal and bearing cooling water system. 4.6, due to the pump medium temperature up to 150 ℃, so be sure to pay attention to safety, do not touch the pump and pipe directly by hand to avoid scalding. If you need to pump maintenance, be sure to wait for the medium temperature to decrease before proceeding. (Editor: Qian Wen, QQ: 2355779329) Recommended reading: 2017 Exhibition Information 2016 Yiwu Fair