Compared to variable frequency constant pressure water supply systems, negative pressure-free variable frequency water supply systems are widely used in actual industrial production and daily life. Many power workers are relatively familiar with variable frequency constant pressure water supply systems, but they know very little about negative pressure-free variable frequency water supply systems. It can be said with certainty that negative pressure-free variable frequency water supply systems have significant advantages over variable frequency constant pressure water supply systems.
I. Working principle of negative pressure-free variable frequency water supply equipment:
When the negative pressure-free variable frequency water supply equipment is put into use, water from the tap water network enters the flow stabilizing tank, and the air inside the tank is discharged from the vacuum eliminator. After the tank is full of water, the vacuum eliminator automatically closes.
When the pressure of the municipal water supply network can meet the water demand, the system supplies water directly to the water supply network through the bypass check valve;
When the pressure of the municipal water supply network cannot meet the water demand, the system pressure signal is fed back to the frequency converter by the remote pressure gauge, the water pump runs, and the speed is automatically adjusted according to the water demand to supply water at a constant pressure. If the running water pump reaches the public frequency speed, another water pump is started to run at a frequency converter.
When the water pump supplies water, if the flow rate of the tap water network is greater than that of the water pump, the system maintains normal water supply. During peak water usage, if the flow rate of the tap water network is less than that of the water pump, the water in the flow stabilizing tank is used as a supplement for water supply.
Second, the advantages of the negative pressure-free variable frequency water supply system.
1. No water tank or reservoir needs to be built. It connects directly to the municipal water supply network, making full use of the existing pressure. It only needs to supplement the water supply as needed, and the equipment stops working when the municipal water pressure meets the load requirements. The system operates at a low frequency most of the time, consuming less electricity, thus achieving significant energy savings of over 50%.
2. Tap water is directly supplied to users after being pressurized by the equipment. The entire process is sealed, so the water source is not easily polluted and the water supply quality is good. It is an environmentally friendly water supply equipment. It adopts microcomputer frequency conversion soft start constant pressure control, so the water pressure is stable and the water pressure quality is good.
3. Short construction period, small footprint, easy installation, and total project investment can be reduced by more than 60%. Using this pressure-free equipment, there is no secondary pollution of the water quality, eliminating the need for purification equipment and further saving investment. Because it utilizes the pressure of tap water itself, energy consumption is low, saving on daily electricity expenses. Since there is no water tank or pool, the cost of regular cleaning and disinfection is also saved.
4. Low operating costs. Due to the smaller size of the booster pump and the use of a multi-pump system, one pump is sufficient to meet water demand during off-peak periods. Other pumps are only activated during peak water demand periods, resulting in very low energy consumption during equipment operation.
5. Property management is convenient and simple. The water supply equipment is digitally controlled and fully automatic. It automatically shuts down during power and water outages and automatically restarts when power and water are restored.
6. The equipment is highly automated and has multiple protection functions such as overcurrent, overheating, phase loss, and water shortage, and has a long service life. Furthermore, there is a public water supply pipeline directly connected to the user's water network, so even if the booster pump stops working during a power outage, users on the lower floors of the building can still maintain water supply.
Third, what conditions are required to use a negative pressure-free variable frequency water supply system?
First, the diameter of the external municipal water supply pipeline used for the negative pressure boosting water supply equipment should be greater than or equal to DN300 mm, and the pressure of the pipeline network in the area should be greater than or equal to 0.22 MPa.
Secondly, the diameter of the water supply pipe in front of the building should be greater than or equal to DN150 mm, and the rated water supply capacity of a single pressurization device should not exceed 32 cubic meters per hour. Furthermore, the total building area of the residential community using this water supply method should not exceed 200,000 square meters, and the community must be able to withstand municipal water outages.
In fact, the negative pressure-free variable frequency water supply equipment surpasses previous water supply equipment in both energy saving and water quality. This is because it breaks through the misconception that it can only pressurize water without negative pressure, and by controlling the fluid flow pattern, it ensures limited pressurization without affecting the pressure of the pipe network. The outlet pressure fluctuation is small and does not affect the pressure of adjacent pipe networks. It can be widely used for direct pressurization of water pipe networks, resulting in significant economic and social benefits.
