Constant pressure water supply is an important factor in the normal operation of the water supply system. The automatic variable frequency constant pressure water supply equipment can quickly adjust the water supply pressure according to the system status, achieving automatic, unattended and constant water pressure. The automatic frequency conversion constant pressure water supply equipment has gradually replaced the traditional water tower and high water tank with its advantages of low investment, short investment recovery period, stable and reliable system operation, small floor space, high efficiency and energy saving, high automation degree and convenient operation control. Various pneumatic water supply equipment.
1. The working principle of automatic frequency conversion constant pressure water supply equipmentThe automatic frequency conversion constant pressure water supply equipment system is composed of a water storage tank, a water pump unit, a circulating soft start frequency conversion cabinet, a pressure sensor, a pipeline network, etc. The frequency conversion cabinet is composed of a frequency converter, a frequency conversion controller (PLC), a low voltage electric appliance, and the like. Pumps generally choose the same model 2~4 units.
The device detects the pressure of the pipe network through the pressure sensor and turns it into an electric signal to the inverter controller. After analysis and processing, the signal is transmitted to the inverter controller to control the pump speed. When the water consumption increases, the pipe network pressure drops. At this time, the pump motor frequency increases, the water pump speed increases, and the water output increases. When the water consumption decreases, the water pump speed becomes slower, the water output is reduced, and the pipe network pressure is maintained. Pressure value. When multiple pumps are running, the machine will be soft-started by the machine, and the frequency conversion will be carried out until the pressure flow is satisfied, which realizes the circulation control of the pump. The timed pump control function set by the system can balance the running time and wear level of each pump and prolong the overall service life of the pump set.
The automatic frequency conversion constant pressure water supply equipment has the characteristics of high efficiency and energy saving, high pressure regulation precision, continuous flow regulation, high degree of automation, complete functions and reasonable operation.
2.1 frequency converter controller:
Although the inverter controller has perfect functions, high reliability, strong applicability and outstanding anti-interference ability, it also has its safety hazards: high requirements for ambient temperature and humidity, insufficient ventilation and high humidity, and harsh working environment. The inverter controller is overheated or the insulation performance is reduced, causing failure; in addition, the safety quality of the equipment itself, unreasonable parameter setting, strong electromagnetic interference, etc. may also cause failure of the inverter controller; if improperly used, maintenance work is not In place, there will also be operational failures, resulting in the inverter not working properly, or even causing premature damage to the inverter, which will affect normal operation. Faults can be manifested as errors in programs and operations, resulting in false inputs, false outputs, and malfunctions or out of control.
2.2 Water pump unit:
In the state of failure of the inverter controller, the pump motor may not be able to realize the conversion between the power frequency and the frequency conversion. The pump runs for a long time at a power frequency, which increases the mechanical wear, or the unit may start and stop frequently, and the pump is subjected to severe temperature. Changes and alternating stresses cause cavitation and water hammer, causing vibration, wear and leakage, resulting in loss of life of pumps, motors and switching devices, or several pumps may not be able to rotate normally. Stirring; water supply equipment for life and firefighting may be caused by fire or water level signal mis-transmission, causing all power frequency of the pumping unit to start, and the pressure on the water supply network is increasing rapidly, seriously threatening the safety of water supply pipelines and water facilities, and at the same time If it is not satisfied, the water pump will be idling and burning. If there are no correct operating procedures, improper operation, poor management and other human factors, it will bring great safety hazards to the pump unit. The paper was published.
3. Improvement of safety of automatic frequency conversion constant pressure water supply equipment3.1 Perfect function design:
(1) According to the system control requirements, reasonable equipment selection, selection of programmable controller, parameter setting and program design are carried out;
(2) The inverter controller has self-protection and fault handling capabilities such as overcurrent, overvoltage, undervoltage, overload, short circuit, overheating, stall prevention, instantaneous power failure protection, automatic power recovery, small flow automatic shutdown, motor temperature automatic control, etc. ;
(3) The pump operation and switching process are fully automatic, with automatic fault alarm, automatic periodic inspection, automatic accumulated working time, automatic timing rotation, automatic exit of fault pump, soft start and soft stop, reducing inrush current;
(4) The monitoring and control of the water level, temperature difference and pressure difference of the reservoir are complete;
(5) Other energy saving and reliability requirements.
3.2 Installation, use and maintenance of the inverter controller
The ambient temperature is controlled between -10 and +40 °C, and the optimum temperature is 25 °C ± 3 °C. It cannot be installed under the electrical components with large heat generation, and there is enough ventilation and heat dissipation space around; the relative humidity of the air is controlled at 95%. The following (no condensation); away from the vibration source, it is inevitable to take shock absorption measures; the control cabinet has good sealing and high mechanical strength.
In terms of anti-jamming, good grounding is ensured, shielded lines are used for control loops, reasonable wiring, strong and weak current separation, distance maintenance, and components such as anti-radio interference filters are added.
In terms of maintenance, strengthen daily inspections and regular maintenance, improve daily operation inspection items, regularly perform power-off maintenance inspections on the inverter, and be familiar with various protection functions to ensure proper use of the inverter and fault finding.
3.3 Establish a remote monitoring system:
According to the intelligent control system of the equipment, remotely monitor, monitor, monitor and record the working status of the water volume, water pressure, liquid level, etc., and feedback real-time information. Statistics and processing of the collected data, management, query and analysis of the network database of the entire system, thereby achieving remote operation, monitoring and fault analysis, and realizing communication control.
While achieving automatic and remote monitoring, we must get rid of the form dependence of “unattendedâ€, especially the handling of fault information, we must adopt a management mode combining remote control and on-site inspection. The operation department shall establish a complete equipment inspection and inspection system, regular maintenance system, and establish strict operational procedures and various emergency plans to strengthen safety awareness and prevent potential safety hazards. The paper was published.
3.4 Setting the device outlet safety valve
The purpose of setting the safety valve is to prevent the damage caused by the overpressure condition when the inverter controller and the pump unit malfunction, and not to prevent the water hammer. The main pipe of the water supply network generally adopts the water supply cast iron pipe. Once the overpressure condition destroys the fixed support of the cast iron pipe in the trench, the pipe will be displaced and the apron interface will be disengaged, causing serious consequences. In addition, the use of overpressure in pipelines and facilities not only has the risk of bursting, but also the rapid opening and closing of water facilities will produce water hammer, which threatens the safety of the water supply system.
In the selection of the safety valve, a closed micro-opening safety valve or a safety relief valve using a liquid such as water as a medium may be selected, and the working principle is: when the pressure in the pipeline exceeds the allowable value, the safety valve will exceed the pressure The allowable value is increased and proportionally opened, and then the whole amount is discharged. When the pressure is reduced to the specified value, the safety valve will be automatically closed to ensure the safe operation of the equipment and the pipeline. The opening degree of the safety valve is a small amount (for the seat throat) 1/40~l/20 of the diameter), it is not allowed to suddenly open or close the water hammer phenomenon.
4. ConclusionSafety is relative, even for automatic variable frequency constant pressure water supply equipment with high technology and advanced technology. As an important part of the infrastructure, the safety of the water supply system must be taken seriously, especially for the residential district water supply system reconstruction project with the purpose of energy saving and process optimization, and the combined water supply equipment and the existing water supply system of the residential community should be combined. The matching situation is closely monitored during the initial operation of the equipment, and the various parameters are repeatedly set to ensure that the energy-saving and safety of the automatic variable-frequency constant-pressure water supply equipment truly achieve long-term stability and reliability.
Detachable Laptop Stand,Foldable Detachable Computer Stand,Detachable Ergonomic Laptop Stand,Detachable And Foldable Aluminum Laptop Stand
Shenzhen ChengRong Technology Co.,Ltd. , https://www.laptopstandsupplier.com