Install the circulating water pump in a system with an open or closed expansion water tank, so that the pump should be in the best position, so that the pump is used to maximize the expansion water tank.

(1) The concept of open or closed expansion water tank system

The expansion water tank in the heating circulation path of heating water furnace is connected with the atmosphere, called the "open expansion water tank system"; the heating water furnace heating circulation channel is isolated from the atmosphere, which is called the "closed expansion water tank system".

(2) The role of an open or closed expansion water tank in the water system

The expansion water tank is one of the main equipment of the mechanical ring thermal heating system. Its role is mainly the pressure of the constant system, the increase in water in the system and compensation system, and also has the effect of exhausting. Usually the expansion water tank is connected to the backwater pipe near the circulating water pump.

The expansion water tank is used in a closed water circulation system, which plays a role of balanced water capacity and pressure, and avoids frequent opening and automatic water replenishment valve to hydrate. In addition to the expansion tank to accommodate the expansion water, it can also play the role of a water supplement tank. The expansion tank is charged into nitrogen, which can obtain a large solvent to accommodate the amount of inflated water. Make up.

The expansion water tank is used in the open water circulation system. The installation location has a great impact on the system pressure. The connection point of the expansion water tank and the heating system pipeline is different. Whether the system is at work or stops, the pressure of this point is constant. The position of the constant pressure point is different, affecting the pressure distribution of the heating system for the water return pipe and the user. Therefore, the determination of the position of the constant pressure point plays a pivotal role in the mechanical circulating hot water heating system. The installation height of the open expansion water tank must exceed the highest water supply height of the highest user and connect to the return pipe of the circulating water pump. The static water pressure of the system is related to the installation of the expansion water tank. As long as the pressure of each point of the system pipeline exceeds the atmospheric pressure, it will not cause negative pressure, and it will not cause the vaporization or inhalation of the air in hot water. In the future, to prevent the incidence of vaporization, air acupoint noise, and bearing damage, the pump inlet should still maintain a certain pressure (generally about 30kPa ~ 40kPa). Due to the swelling water tank connected to the circulating water pump inlet, the height of the expansion water tank is installed, so It can meet the minimum pressure required for the pump inlet when transporting different temperature liquids.