When the tap water pressure is insufficient, the booster pump
should be used for boosting. The heating system should use a circulating pump to overcome the resistance and increase the cycle power of the system. In practical applications, it is usually necessary to use multiple pumps in series or in parallel. The purpose of the tandem pump is to increase the lift, while the purpose of the parallel pump is to increase the flow.
First, the choice of pump
1. Select the pump according to the purpose
If you want to increase or stabilize the home water pressure, you can use a small booster pump; if you want to overcome the system resistance and increase the circular power of the system, you should use a circular pump.
2. Select the pump based on pressure and flow.
The pressure mentioned here means that the pressure provided by the pump is greater than the total pressure loss of the system. If there is a pressure head in the construction drawing, the pump selection must meet this requirement. In addition to considering pressure, we should also consider the impact of water flow. The greater the water flow, the smaller the useful pressure provided by the pump. Conversely, when the water flow is 00:00, the greater the pressure, the greater the maximum pressure.
In addition to considering the diameter of the pump and the diameter of the pipe, the choice of booster pump should also consider whether the selected power and head can be really lifted and adjusted, and should be considered for ease of use.
A static head with no water flow when determining operating voltage, current, head and flow, bore and maximum pump head. If the user asks to pump water to a certain height and maintain a certain flow rate, the pressure head required to select the pump must be higher than the specified pumping height. It can be determined by referring to the head flow curve.
Choose volume and shape requirements (threaded interface, inlet and outlet directions, caliber, etc.).
Determine the working environment (temperature, medium).
Determine functional requirements (time control, motion control, pressure control, flow control, speed control, etc.).
The so-called convenient use means that the water pump has a control function; when the hot water valve is opened, the water pump operates; when the hot water valve is closed, the water pump stops running, so that the water pump is still running after the valve is closed, thereby damaging the water pump. What kind of booster pump can I choose to solve this problem? That is the automatic booster pump.
The automatic booster pump works on the principle that when there is water flow, the built-in water flow sensor can connect the pump power by detecting the water flow. When the water flow becomes small or equal to zero, the turbine rotor decelerates or stops running, and the pump power is cut off. Another solution is the external water pressure switch of the booster pump. When the valve is opened, the pressure difference increases, the water pressure switch operates, the power is turned on, and the pump is started. When the valve is closed, the pressure difference is reduced, the water pressure switch is returned, the power is turned off, and the pump is stopped. This method of installing an external hydraulic switch is cumbersome.
2. Determination of the installation position of the circulating water pump in the open or closed expansion tank system
When the circulating water pump is installed in a system with an open or closed expansion tank, the pump should be in an optimal position so that the pump can make maximum use of the expansion tank.
1. Expansion tank system concept
The expansion water tank in the heating circulation path of the heating furnace is connected to the atmosphere called "open expansion water tank system", and the expansion water tank in the heating circulation path of the heating water heater is isolated from the atmosphere, and is called "closed expansion water tank system".
2. The role of the expansion tank in the water system
The expansion tank is one of the main equipment for mechanical ring hot water heating systems. Its main function is to keep the pressure of the system constant, to regulate and compensate for the expansion and contraction of water in the system, and to vent. The expansion tank is usually connected to a return water main pipe near the suction port of the circulation pump.
The expansion tank is used in the closed water circulation system to balance the water capacity and pressure, avoid frequent opening of the safety valve and frequent filling of the automatic replenishment valve. The expansion tank also plays the role of filling the tank while accommodating the expanded water. The expansion tank is filled with nitrogen gas, and a larger solvent can be obtained to accommodate the expanded water. The high pressure and low pressure expansion tanks can use their own pressure to supply water to the pressure stabilization system in parallel.
When the expansion tank is used in the boiling water circulation system, its installation position has a great influence on the system pressure. The position of the connection point between the expansion tank and the heating system is different, which determines the position of the system constant pressure point. That is to say, regardless of whether the system is working or stopped, the pressure at this time is constant. In the heating system, the positions of the constant pressure points are different, which affects the pressure distribution of the supply and return pipes and the user. Therefore, the determination of the constant pressure point position plays an important role in the mechanical circulating hot water heating system. The installation height of the open expansion tank must exceed the maximum user's irrigation height and be connected to the return water inlet of the circulating water pump.
The static pressure of the system is related to the installation height of the expansion tank. If the pressure at each point of the system piping exceeds atmospheric pressure, no negative pressure will occur and steam will not be vaporized or air will be drawn in. In order to prevent vaporization, cavitation noise and bearing damage, the pump suction port must maintain a certain pressure (usually 30kPa to 40kPa). Since the expansion tank is connected to the vicinity of the suction port of the circulating water pump, the installation height of the expansion tank can be changed to meet the minimum pressure required for the suction port of the pump.
Third, the installation of the booster pump
If the installation site is a high-rise building with a high level and the water pressure is low, consider installing a booster pump in the water pipe. When selecting a pump and installing it, consider that the pump interface is the same as the tap water interface.
1. Pump installation position
The booster pump is usually installed at the home water meter, that is, when the water meter comes out, it can also be installed in front of the gas water heater inlet. When installing at the hot water outlet, a hot water pump should be used, and the temperature should be above 85 °C.
2. Installation of the pump
Disassemble the cold water valve at the inlet of the water heater, install a booster pump at the appropriate position in the lower right corner of the water heater (two self-propelled screws are fixed on the wall), and connect the water pump to the cold water outlet pipe of the water heater with a metal hose or an aluminum plastic tube; The external hydraulic switch is normally connected to the inlet section of the booster pump and must be indicated by an arrow according to the command. The automatic booster pump does not require an external hydraulic switch.
3. Precautions for pump installation
Before installing the diesel water pump,
carefully read the installation and operating instructions and follow the instructions.
Check the power data on the pump nameplate to confirm that the pump is suitable for use with the power supply and that the socket is grounded reliably.
The connection in the pump's junction box can only be made when the power is off.
The hot water pump should be installed on the pipe where the liquid flows upwards.