Basic knowledge of variable frequency constant pre

Basic knowledge of variable frequency and constant pressure water supply

I. characteristics of variable frequency and constant pressure water supply

1. Energy saving, 20%-40% power saving and green power consumption can be achieved

2. Small floor area, less investment and high efficiency

3. Flexible configuration, high degree of automation, complete functions, flexible and reliable

4. The operation is reasonable. Due to the soft start and soft stop, it can not only eliminate the water hammer effect, but also reduce the average torque and wear on the motor shaft, reduce the maintenance volume and maintenance cost, and greatly improve the service life of the water pump

5. Because the frequency conversion constant pressure speed regulation directly supplies water from the water source, the secondary pollution of the original water supply mode is reduced, and the source of many infectious diseases is prevented

6. Through communication control, unattended can be realized, saving human and material resources

II. Energy saving principle

it can be seen from the working principle of the water pump that the flow of the water pump is proportional to the speed of the water pump (motor). The hydraulic universal experiment can complete the stretching and tightening twists and turns of the data. The head of the water pump is proportional to the square of the speed of the water pump (motor), and the shaft power of the water pump is equal to the product of the flow and head, Therefore, the shaft power of the water pump is directly proportional to the third power of the speed of the water pump (that is, the shaft power of the water pump is directly proportional to the third power of the power supply frequency). According to the above principle, changing the speed of the water pump can change the power of the water pump

basic formula of flow: Q ∝ NH ∝ N2 kw=q*h ∝ N3

above Q represents flow, n represents speed, H represents lift, kW represents shaft power

for example, if the power supply frequency is reduced from 50Hz to 45hz

then p45/p50= (45/50) 3= 0.729, that is, p45=0.729 P50

reduce the power supply frequency from 50Hz to 40Hz,

then p40/p50= (40/50) 3= 0.512, that is, p40=0.512 P50

the pump is generally 1 The mechanical transmission is composed of harmonic reducer, arc synchronous belt and ball screw pair to realize gapless transmission. The maximum working condition demand of the water supply system is considered in the design. However, the water system may not reach the maximum amount of water for a lot of time in actual use. Generally, the valve is used to adjust and increase the resistance of the system to throttle, resulting in the loss of motor power consumption. The use of frequency converter can make the working state of the system smooth and stable, The water supply can be adjusted by changing the speed, and the investment can be recovered by reducing the speed and saving energy

III. main applications of variable frequency speed regulation constant pressure water supply equipment

1. Domestic water for high-rise buildings, urban and rural residential areas, enterprises and institutions

2. All kinds of industries need water with constant pressure control. Cold DuPont Hongji combines its development (4) environmental protection forces to reach a resonance strategy, and establishes the "environmental protection new energy utilization biaxially stretched polyester film project" water circulation, thermal water circulation, boiler water replenishment, etc

3. Central air conditioning system

4. Water plant pressurization system

5. Farmland irrigation, sewage treatment, artificial fountains

6. Various fluid constant pressure control systems. (end)