At present, with the increasingly accelerated pace of urbanization in China, land resources are becoming increasingly scarce, and construction projects are generally developing in the direction of high-rise buildings. At present, how to achieve reliable and safe water supply in high-rise building water supply systems, and how to achieve energy saving and environmental protection have become key research topics in water supply system design.
Many construction companies have effectively alleviated the water supply problems of high-rise buildings by using non-negative pressure water supply technology. At the same time, they have effectively ensured the continuous operation of water supply pipelines by using voltage stabilization, frequency conversion and other technologies, and realized intelligent water supply. Based on this, this article analyzes the application of non-negative pressure water supply technology in high-rise building water supply systems, in order to provide reference for industry professionals.
The water supply pressure of the municipal water supply network is usually less than 0.3MPa, which cannot meet the water demand of high-rise building users. At the same time, due to the high probability of causing secondary pollution and often occupying a large roof space, traditional high-level water tanks are difficult to meet people’s requirements for quality of life. Therefore, in the traditional high-rise building water supply design, designers often adopt a water supply method that combines underground water tanks with variable frequency pump groups to achieve zoned water supply. At present, based on the building concept of energy saving and environmental protection, the water supply method needs to be improved and innovated to provide users with more efficient and fast water supply services. Based on this, based on many years of experience in building water supply design and construction, we mainly analyze the application of non-negative pressure water supply technology in high-rise building water supply systems.
1. What Is Non-Negative Pressure Water Supply Technology?
Non-negative pressure water supply technology is one of the technologies commonly used in urban water supply systems. This technology mainly uses frequency conversion technology to increase the pressure of municipal water supply pipelines, aiming to meet the water supply needs of users in high-rise buildings. Compared with the traditional water supply method of building a reservoir, the non-negative pressure water supply system is directly connected to the water pipeline, eliminating the water storage and water supply links of the reservoir and reducing energy consumption. The pressure stabilization and compensation technology in the non-negative pressure water supply technology can stabilize the pressure of the water supply network, and the intelligent control technology can monitor the network in real time, which not only saves time and effort, but also realizes intelligent regulation of water pressure to ensure continuous water supply. It should be noted that before using the system, construction personnel need to set the pressure stabilization value according to the actual water use situation, and use the corresponding fine-tuning technology to control the water pressure, so as to avoid water supply problems caused by excessive water pressure, and even affect the normal life of users. In addition, the non-negative pressure water supply system adopts vacuum compensation technology, that is, through a fully closed series connection to avoid impurities from mixing into the water supply network, so as to avoid problems such as blockage of tap water pipelines and reduced quality of drinking water.
2. Types Of Non-Negative Pressure Water Supply Equipment
2.1. Sealed non-negative pressure water supply equipment
Sealed non-negative pressure water supply equipment uses stainless steel containers. Technicians usually completely seal the motor, water pump and other equipment to avoid secondary pollution of the water quality. At the same time, this type of device is commonly found in places such as stairwells and underground water pools, and has the advantages of small space occupation and simple and quick installation. Its disadvantage is that when the municipal public pipeline network is cut off, due to the limited storage capacity of the stainless steel container, the equipment is likely to be cut off after running for a period of time.
2.2. Flow regulating tank type non-negative pressure water supply equipment
The flow regulating tank type non-negative pressure water supply equipment achieves the purpose of adjusting water pressure and water volume by installing a controllable flow regulating valve in front of the water pump, thereby reducing the impact of the urban public water supply system on it.
2.3. Adjustable water tank type non-negative pressure water supply equipment
The adjustable water tank type non-negative pressure water supply equipment is equipped with an adjustment water tank, which ensures that the water source in the water tank is circulated twice a day by adjusting the parallel connection between the water tank and the water pump and the adjustment of the electronic control device, thereby ensuring the water quality. The mechanism of the device is: when the water volume and water pressure conditions of the water supply network meet the requirements, water is directly supplied by the city network; if the conditions cannot be met, water is directly taken from the adjustment tank. Therefore, when the city water supply pipeline is unstable, designers of high-rise buildings can choose the adjustment tank type non-negative pressure water supply system.
3. Principles And Advantages Of Non-Negative Pressure Water Supply Technology
3.1. Principle of non-negative pressure water supply technology
Non-negative pressure water supply device can be regarded as a pressurized water supply device. When using this device, construction personnel should connect the device to the water supply network to make full use of the residual pressure in the urban network to form a cascaded series water supply system, so as to ensure that the network pressure reaches the set protection value. When using non-negative pressure water supply equipment, construction personnel must consider the working conditions of secondary pressurized water supply to avoid negative pressure problems, so as to ensure safe and reliable water supply and reduce the impact on the normal water use of surrounding users. The new non-negative pressure water supply system is a high-tech equipment system that integrates advanced electromechanical control technology. When the urban water supply network is short of water, the main technical principles used by the system are as follows.
- Prevent negative pressure: The system will automatically open a vacuum regulating valve to inject outside air into the stable current compensation system to prevent negative pressure and other phenomena.
- Control and limit flow: The pressure sensor of the system will appropriately limit the water volume according to the monitored signal to ensure that the water pump will not overload water.
- Adjust pressure: The system will automatically switch to the constant pressure water supply mode, and then automatically switch back to the variable frequency mode after the pressure returns to normal. At the same time, the system can also use the non-negative pressure water supply equipment to achieve the regulation and storage of the overall water supply network.
3.2. Advantages of non-negative pressure water supply technology
- Prevent secondary pollution: The sealing of non-negative pressure water supply equipment is generally high, and it is not easy to be invaded by microorganisms. It will not cause secondary pollution and greatly reduce the occurrence of water leakage problems.
- It is conducive to energy saving: The non-negative pressure water supply system is directly connected in series with the urban water supply network, which effectively reduces the energy consumption generated during the water supply and water supply process; coupled with the assistance of variable frequency technology, compared with the traditional water supply system, the system can save nearly half of the energy consumption.
- High operating efficiency and low management costs: The non-negative pressure water supply system has a high level of mechanization, which can significantly improve the management efficiency of staff without increasing management costs.
- Effectively reduce investment costs: Traditional water supply methods require the construction of new pools or high-level water tanks, which are expensive and usually require a large roof space. However, non-negative pressure water supply technology effectively avoids these problems.
- High level of automation: Non-negative pressure water supply technology can stabilize water supply by pressurizing the non-negative pressure pipe network; it can use simulation intelligent technology to automatically control the water volume; it can automatically sound voice alarms when special situations such as overpressure, overcurrent, overload, and water shortage are detected. In addition, the non-negative pressure water supply system also supports customer-customized remote monitoring services, and builds a central monitoring center according to customer needs to achieve 24-hour monitoring of the water pump’s current, voltage, inlet and outlet water pipe pressure, water pump frequency, etc. In addition to using the monitoring center to start and shut down the equipment, customers can also remotely handle some soft faults, thereby greatly reducing management and maintenance time.
4. Precautions For Applying Non-Negative Pressure Water Supply Technology At Different Stages
4.1. Design stage
The connection design between high-rise building water supply facilities and urban water supply network is the key to the design of non-negative pressure water supply system. Therefore, designers need to focus on the connection between water supply equipment, water supply pumps and municipal water supply network, so as to achieve energy-saving and efficient control of negative pressure water supply problems and ensure user water demand.
When tap water enters the regulating tank of the non-negative pressure water supply system, the vacuum suppression device will discharge the gas in the water tank. When the regulating tank is filled with water, the vacuum suppression device will automatically stop operating. In addition, when the building water demand and pipeline pressure meet the use requirements, designers can use bypass check valves for water supply; if they cannot meet the requirements, the pressure controller, sensor, power meter, etc. in the non-negative pressure water supply system will send corresponding signals to the water pump to activate the water pump and start working.
During the operation of the water pump, if the water flow in the pipeline is less than the water flow of the water pump, the designer needs to reasonably adjust the water volume in the water tank according to the actual situation. At this time, the outside air will enter the vacuum damper, thereby reducing the pressure in the pipeline. After the peak of water consumption ends, the water volume in the pipeline network will also be redistributed. When the water volume in the pipeline exceeds the water volume of the water pump, the water supply system will maintain its original operating state; and when the water level in the adjustment tank continues to drop, the liquid level controller will sound an alarm and prompt the water pump to stop working.
In the case of low water consumption in high-rise buildings, designers can use small diffusers to supply water, that is, by maintaining a certain working frequency, ensuring the working head of the water pump, thereby ensuring water supply.
4.2. Preparation stage
Non-negative pressure water supply technology can improve the water supply structure inside high-rise buildings, so that the water supply system can meet the water demand of different floors. Before using non-negative pressure water supply technology, technicians must analyze the water supply pipelines in various regions in detail to determine the water supply range and ensure that the pipelines can supply water continuously. Technicians should also clarify information such as the pumping location, the number of residents, and the water supply point, so as to reasonably set the pressure stabilization value and create an excellent water supply environment for users. At the same time, after a detailed investigation of the house layout and living area, the technicians should compare the actual situation with the theoretical value, focusing on analyzing the life of the relevant equipment, energy consumption, water quality in the area, and other factors, so as to formulate an environmentally friendly, scientific and cost-effective construction plan. In addition, the technicians should strictly review the quality of the equipment before the relevant equipment enters the site, so as to avoid problems such as water supply system failure caused by equipment quality problems.
4.3. Construction phase
To ensure the normal and stable operation of the non-negative pressure water supply equipment, before installing the equipment, the construction personnel must carefully check and clean the hard debris inside the water pump to prevent it from damaging the impeller, pump body, etc. during the operation of the equipment. At the same time, during the pipeline installation process, no one can apply weight pressure to the water pump to avoid deformation of the water pump and affect the normal operation of the water pump. After the equipment is installed, the construction personnel need to tighten the anchor bolts in time to prevent vibration when the water pump is started and affect the stability of the water pump. In addition, the construction personnel should also install a regulating valve on the inlet and outlet pipes of the water pump, and install a pressure gauge on the outlet pipe of the water pump, so that the relevant management personnel can check or adjust the working status of the water pump at any time to ensure the normal operation of the water pump. It should be noted that before the first use, the construction personnel should also conduct comprehensive cleaning, purging and other treatments on the entire non-negative pressure water supply system to prevent dirt from mixing into the pump body and causing equipment damage.
After the non-negative pressure water supply equipment is officially put into operation, the management personnel should frequently check the temperature of the bearing parts of the water pump and motor, and lubricate them regularly. If an abnormal sound is found in the bearing during the inspection process, the management personnel should immediately find out the cause (for example, whether the anchor bolts of the equipment are loose, whether the dripping water at the water pump packing is qualified, etc.) and deal with it in time. At the same time, the management personnel should also regularly repair and maintain the pipeline system of the non-negative pressure water supply equipment, and pay attention to check whether there is any leakage in the pipeline from the water storage tank to the high-pressure storage tank, the total outlet of the pipe network, etc. If there is, it must be dealt with in time.
5. Key Points For The Application Of Non-Negative Pressure Water Supply Technology In High-Rise Building Water Supply Systems
5.1. Scientific selection of non-negative pressure water supply systems
- Not all high-rise buildings are suitable for installing non-negative pressure water supply equipment. Relevant designers should consider the actual situation of the building and choose carefully.
- The adjustment volume of non-negative pressure water supply equipment is relatively small, so it is relatively dependent on the urban water supply system and is not suitable for areas such as suburbs where water pressure conditions are poor and flow and water pressure cannot be guaranteed.
- The normal operation of the non-negative pressure water supply system is inseparable from stable and reliable power supply. Therefore, the use of non-negative pressure water supply systems is restricted in places with poor power supply conditions.
- Industrial buildings that produce toxic substances and chemical products and are likely to have an adverse impact on urban pipe network management should not use non-negative pressure water supply systems.
5.2. Design and selection of non-negative pressure pipe network superposition transfer equipment and pipe network setting
In the design of the water supply system of high-rise buildings, designers should flexibly select the series water supply pump room according to the building height and the actual layout of the refuge floor. The principle of selection is: it must meet the requirements of the upper water supply division and not bring too much pressure to the transfer network. The pipe network stacking device of the refuge floor should be separated from the high-rise domestic water supply area. Designers can set up a pipe network stacking device in each division and select the number of pumping of each device based on the design second flow rate. If the building is a series combination space, the corresponding pressure level of the stacking device in each division must be determined according to the water supply pressure of the space where it is located. When selecting the transfer pump, the designer must clarify the total flow of each area so that it can be controlled by frequency conversion. At the same time, a small water pump and air pressure box must be configured for the transmission pump to ensure the water demand of small flow at night. As for the transfer network, the author recommends the use of a ring water supply system, that is, the stacking devices in each division are uniformly pumped by the ring network. This method simplifies the control link, avoids the situation where each division is set up with a separate transfer device, and can effectively reduce the total number of pipelines in the building and save floor space. In addition, since the transfer pump group is equipped with multiple backup water pumps in advance, even if the transfer pump fails, it will not affect the normal water supply of the system, and it can leave enough time for maintenance personnel to deal with the failure.
5.3. Comprehensive consideration of technical and economic factors
When adopting non-negative pressure water supply technology, construction companies should fully consider the construction cost, operating costs and other financial factors of the technology, and strive to achieve a balance between technical and economic factors. In this regard, construction companies can start from the perspective of economic benefits and comprehensively compare the expenditures and benefits of single high-level water tanks, water pumps, water supply pressure tanks, underground water tanks, constant pressure variable frequency pumps, superimposed water supply equipment, non-negative pressure water supply equipment, etc., and then fully utilize the advantages of non-negative pressure water supply technology while ensuring that the investment is minimized.
6. Conclusion
In summary, under the background of rapid development of the construction industry, the number of high-rise buildings is increasing, and how to strengthen water supply design and control water supply pressure has become a key research topic in the current water supply system design. Therefore, construction companies and related personnel must deepen the application points of non-negative pressure water supply technology to ensure the rationality and scientificity of water supply design and construction plans, and ultimately ensure the safe and sustainable water supply of high-rise buildings.