Understand the working principle and difference between frequency conversion constant pressure water supply equipment and non negative pressure water supply equipment
2021-03-09
The frequency conversion and constant pressure water supply equipment is a new type of energy-saving water supply equipment. The water supply equipment with frequency conversion and constant pressure is a high-tech energy-saving water supply device which combines frequency converter governor and motor pump by using the most advanced microcomputer control technology. The variable frequency constant pressure water supply equipment takes the water pressure (or user water flow) at the outlet of the pump as the setting parameter, and automatically controls the output frequency of the frequency converter through the microcomputer to adjust the speed of the pump motor, and realizes the closed-loop adjustment of the water pressure of the user network, so that the water supply system can automatically stabilize at the set pressure value: that is, when the water consumption increases, the frequency increases, the pump speed is accelerated; when the water consumption is reduced, the water consumption will be reduced , frequency is reduced and the pump speed is slow. This ensures that the entire user network has sufficient water pressure (consistent with the pressure set by the user) and water quantity (varying with the user's water consumption).
Composition of variable frequency and constant pressure water supply equipment
The water supply equipment with variable frequency and constant pressure is mainly composed of water pump unit, pressure pressure stabilizing tank, pressure sensor and frequency conversion control cabinet, which can always maintain the pressure of pressure gauge (i.e. water pressure of user network) equal to the user set value. It can be used for general life or production water supply. The water supply system consists of:
1. The frequency conversion water supply equipment and municipal pipe network are connected to the constant pressure water supply. When the water supply pressure can meet the needs, all the pumps will be shut down automatically. Otherwise, the constant pressure water supply equipment starts and the pressure increases to meet the water demand.
2. Additional small pump or air pressure tank can increase auxiliary small pump or auxiliary air pressure tank to completely eliminate the power consumption of small flow or zero flow water supply. When the water supply pressure is low, the main pump will be stopped automatically to make the small pump or air pressure tank run.
Function characteristics of water supply equipment with frequency conversion and constant pressure
① No negative pressure for water supply equipment with frequency conversion and constant pressure
The direct connection of the system and municipal pipe network will not cause negative pressure of municipal water network.
② Setting pressure of variable frequency and constant pressure water supply equipment
The allowable water absorption pressure of municipal water network can be set by adjusting the permitted pressure control valve.
③ Variable frequency constant pressure water supply equipment pressure borrowing (or overpressure)
The pressure of tap water network can be pressurized on the basis of the allowable suction pressure and flow rate. Compared with the water absorption from the common reservoir, the number of pumps or (and) the speed can be reduced to achieve the purpose of energy saving.
④ Variable frequency and constant pressure water supply equipment
The equipment detects the outlet pressure through sensors in real time, compares the detection value and the set value, determines the number of sets of motor and pump input station and frequency of inverter output (reflecting the motor and pump as the speed) to realize constant pressure by sticking the water curve.
Application scope of variable frequency and constant pressure water supply equipment
◆ the new residential quarter, villa, office building and comprehensive building are used for water supply.
◆ domestic water supply for high-rise buildings, fire fighting water, high-level hotels and hotels, etc.
◆ the traditional water supply system transformation, such as air pressure water supply and ground water tank pressure.
◆ various boiler cold water supply system and boiler hot water.
◆ the intermediate pressure pump station and secondary pressurization of tap water in the water plant.
◆ the production, domestic water and pipe network of all mining enterprises are stabilized.
◆ various types of circulating water and cooling water supply system.
Non negative pressure water supply equipment
The non negative pressure water supply equipment consists of three parts: air pressure tank, water pump and electric control system. The outstanding product features that water tower is not needed, small sponsorship, less land occupation, flexible layout and fast construction and production. The water and gas automatic regulation, automatic operation, energy saving and tap water are connected automatically. After power failure, water supply can still be provided. After commissioning, it is not necessary to watch. It is widely used for water supply for production, living and office of enterprises and institutions, residential areas and rural areas. It is suitable for places with water supply households within 5000 households and daily water supply volume within 3000 m3, and water supply height is more than 100 meters. It is usually located on the ground or basement. Units with tap water can adjust the peak water consumption and increase the water pressure by using the non negative pressure water supply equipment. When using the water in peak, it can meet the water demand of large area and high-rise building. Units, factories or rural areas without tap water need to connect the equipment with water source power, and then get stable water pressure and meet the water demand. Compared with other old water supply equipment, the equipment saves 3-16 times of land occupation, and saves 15% - 60% sponsorship compared with the construction of water tower. The equipment is small in volume, easy to assemble, installed and debugged, short in transportation and equipment installation period, complete protection function of non negative pressure water supply equipment, safe and reliable operation and convenient operation. The main machine of the equipment adopts frequency converter, which has the main functions of undervoltage, over-voltage, over-current, overload, short circuit, overheating, stall prevention and other protection functions, and the trouble free operation can reach more than 100000 hours. The distribution control part of the equipment adopts the intelligent control principle, which is convenient and practical to operate, and the working condition of the equipment is clear at a glance, so that the non professional personnel can quickly master it.
The main functions of the non negative pressure water supply equipment are complete, the insurance coefficient is high, and the emergency main function can be used to continue water supply in case of partial failure of the equipment. The equipment can be connected with municipal water supply network automatically and has the main function of double frequency conversion, that is, it can meet the normal pressure and flow of domestic production water, and can automatically convert to high-pressure and large flow water supply in case of fire, and can be used in one machine and multiple purposes.
Installation of equipment for non negative pressure water supply equipment
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The equipment installation should be conducted in a well ventilated, dust-free and non humid place with an ambient humidity of -10 ℃ -40 ℃. Rain proof and lightning protection facilities shall be set up outdoors.
After the site is selected, the foundation shall be treated, the concrete pouring or the tank support base shall be built with brick and stone. After the base is completely solidified, the tank body shall be lifted and placed stably. Then the equipment shall be installed with accessories and power on.
The use method of non negative pressure water supply equipment
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Before trial operation, the water supply valve shall be closed first, and the sealing valve shall be checked. Leakage is not allowed. After starting, attention shall be paid to the steering of the pump. When the pressure gauge pointer reaches the upper limit, the pump stops automatically. Open the water supply valve to supply water normally. If it is necessary to supply water regularly, turn the selection switch to the manual position.
Main functions of non negative pressure water supply equipment
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one
The soft start, frequency conversion to power frequency operation and stop of multiple water pump units are completed automatically.
two
According to the change of water consumption, it becomes the start and stop of multiple pump sets.
three
LED display with pressure setting value and actual pressure value is the main function.
four
Led frequency indication, abnormal frequency conversion indication, motor fault condition display.
five
Main functions of protection: it has the main functions of undervoltage protection, over voltage protection, overload protection, short circuit protection, stall prevention, burning loss prevention and so on.
Scope of application of non negative pressure water supply equipment
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The user who draws water from the water supply system of the water company. For example: users who use water from the surface or pool for water from high-rise buildings and residential quarters in cities. For example: the boiler variable frequency constant pressure water replenishment system of the user heating system directly from the bottom water is taken from the deep well pump or submersible pump. Because of its reliable performance, simple structure, convenient operation, low investment, it is widely used in small and medium-sized water supply systems in industrial and mining enterprises, towns, rural areas, etc., especially for the water sources for self-contained wells, underground pools and reservoirs.
The principle of frequency conversion control of non negative pressure water supply equipment
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The energy saving effect is very significant (calculated according to the specific situation) compared with the constant pressure water supply by regulating valve.
The product features
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one
Starting balance, starting current can be limited to rated current, thus avoiding the impact on the power grid during starting;
two
The average speed of the pump is reduced, which can extend the service life of the pump and valve;
three
It can eliminate the water hammer effect when starting and stopping;
Generally speaking, when a frequency converter controls a motor, it is only necessary to make the capacity of the motor used by the inverter match the actual motor capacity. When one inverter controls two motors at the same time, in principle, the capacity of the motor used for the inverter shall be equal to the sum of the capacity of the two motors. However, if the water supply at peak load is much different from the full speed water supply of two pumps, it is advisable to reduce the capacity of the converter appropriately, but enough capacity shall be reserved for the operation precautions.
Working principle of non negative pressure water supply equipment
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The control mechanism is composed of AC frequency converter, remote pressure gauge and regulator, and the circuit breaker and contactor are the actuators to constitute a complete constant pressure variable water supply system. Working status of two pumps: No.1 pump operates in frequency conversion, and the frequency rises to a set value to reach the set pressure, and the frequency conversion device works at constant pressure. When the water consumption increases, the pressure drops. After the pump maintains a certain set value frequency for a period of time, if the set pressure is not reached, it will automatically turn to the power frequency operation of No. 1 pump and start the frequency conversion work of pump 2. When the water consumption is reduced, the No. 1 pump stops, and the frequency rises to a certain set value from pump 2 to maintain the set pressure and plays a constant pressure variable role.
Characteristics of non negative pressure water supply equipment
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one
The non negative pressure water supply equipment is fully automatic controlled by microcomputer, and the frequency conversion and speed regulation operation are controlled automatically. The power cut equipment will stop automatically and the incoming call will start automatically, and it can be fully automatic.
two
The equipment is made of multi-stage stainless steel pressure pump, pump shell, impeller and main accessories made of food grade stainless steel, smooth circulation, high efficiency and energy saving, stable operation, extremely low noise, excellent performance of the whole machine, which is an ideal green and environmental protection and energy-saving water supply equipment.
three
It is not necessary to build water tank or water tank, nor large air pressure tank, which saves a lot of investment, and makes full use of the pressure of water pipe network.
four
The water supply system is completely closed from the water pipe network to the user tap. Pollutants will not enter the system, water body will not contact with air directly, and the filter parts are made of food grade stainless steel, no secondary pollution opportunities, environmental protection and sanitation.
five
The energy saving effect is remarkable. The equipment is directly connected with the tap water pipe. The pressure required for superposition on the basis of the pressure of the primary water supply network in the water plant is different and how much is compensated. The pressure of the pipe network can be fully utilized. The water consumption is low peak period, and the equipment does not need to operate. Compared with the traditional water supply equipment, the energy saving reaches 30% - 90%
six
Water resources are saved, and regular cleaning and disinfection are not required, and water and human resources are not wasted. Save maintenance costs.
seven
The land occupation area is small, and it is unnecessary to build reservoir or water tank without large air pressure tank, which greatly saves the area of the system. The land saved can be used to improve the utilization rate of real estate, which meets the requirements of the state to save land.
eight
The installation is simple, only the water inlet and outlet pipes need to be connected, and the construction period is short and the installation is simple.
nine
Stable operation, small vibration, low noise (noise value less than 50 dB).
ten
The system water supply is stable, and the system end pressure is fully guaranteed.
eleven
It can add automatic inspection function to reduce the property management cost.
twelve
PLC can be used to control the automatic operation, easy operation and maintenance.
thirteen
Integrated professional design, compact structure, less investment, convenient installation, beautiful appearance.
fourteen
The effect of energy saving is good by using the superposition of pressure of pipe network and the operation mode of automatic frequency conversion.
