The application of Oerui inverter in fan and water pump

III. Preface

With the rapid development of science and technology and the continuous application of new products, the rapid development of industrial enterprises has been greatly promoted, and the reduction in production energy consumption has directly brought about a reduction in production costs, thereby enhancing the competitiveness of enterprise products in the market. .

In recent years, due to the increasing tension in energy and the continuous rise in prices, many companies have struggled. Therefore, the work of saving energy and reducing consumption in front of enterprises is very important. It is imminent to carry out technological reforms for obsolete and outdated equipment. In particular, many machinery and equipment products produced during the 60s and 70s have retained sufficient room in terms of design, manufacturing, type selection, and many other aspects. There is a serious phenomenon of large horse-drawn carts in the configuration of power equipment and machinery and equipment. This is especially true for fans, pumps, and air compressors used in production. As far as the specificity of the chemical industry production is concerned, there is a huge amount of energy wasting and energy saving, but relying on the traditional control methods in the past to achieve the purpose of energy conservation is still an empty phrase.

Fourth, transformation analysis

At present, most of the old chemical enterprise fans and pumps are widely used, but they are old and inefficient, and all belong to long-term operation. However, as the country's energy-saving emission reduction efforts continue to increase, many companies began to make energy-saving changes to the old equipment.

Because the fan pump is a square load, it can be seen from the following figure (slightly) that the wind pressure increases but the shaft power is proportional to the area BH1OQ2. Obviously, the shaft power does not drop much. If the inverter speed control method is adopted, the fan speed is reduced from n1 to n2. According to the proportional law of the fan parameters, the characteristic of the speed n2 air flow (QH) is drawn, as shown by the curve (4). It can be seen that under the condition of satisfying the same amount of air flow Q2, the wind pressure H3 is greatly reduced, and the power N3 is significantly reduced with the area CH3OQ2. The saved power ΔN=(H1-H3)×Q2 is represented by the area BH1H3C. Obviously, the economic effect of energy saving is very obvious.

Since most of the old companies still do not know much about frequency conversion energy conservation, we must follow the principle of “promoting them gradually and gradually”. During the energy saving reform of fan and water pump at a chemical fertilizer plant in Sichuan, the frequency conversion energy-saving technology of a 55KW water pump motor was first reformed with Europian F2000-P frequency converter. In terms of the production conditions at that time, the calculated energy-saving rate was 20%. Because the pump is running for a long period of time, its energy-saving effect is considerable. Due to the considerable energy-saving effect, the frequency conversion energy-saving technology has been well promoted in this fertilizer plant, so that in turn several sub-lots have installed frequency converters on motors with different total installed capacity of 938.6KW.

Statistical results show that the average integrated energy-saving rate is about 15%. According to the different loads and changes in the production process, one of the 37KW fans, a 95KW air compressor, a 30KW and a 22KW pump, the power-saving effect is more significant, reaching 40 to 75%. Greatly reduce the production energy consumption of enterprises, enhance the market competitiveness of the company's products, and reduce the mechanical wear of equipment through frequency conversion transformation, saving maintenance costs, improving the labor intensity of operators, but also because the inverter has a variety of The protection function makes the motor protected under various fault conditions.

It should be pointed out here that in the frequency control of machinery and equipment, it depends on the specific conditions of the production process and the configuration of the mechanical power, otherwise it will outweigh the gains, affecting the normal production and energy-saving effect.

Fifth, the principle of transformation

Taking a 37kW centrifugal fan as an example, in order to ensure that the wind pressure of the fan can meet the production process requirements, it is necessary to install a pressure sensor in the air duct to make the inverter perform pressure closed-loop operation. The pressure sensor detects the pressure of the air duct and sends a 4-20mA current signal to the F2000-P inverter. The PID operation of the inverter automatically adjusts the motor speed to achieve the purpose of stabilizing the wind pressure of the air duct. The schematic (slightly) is as follows:

Sixth, after the transformation of energy-saving calculation

According to the calculation results, the total investment cost can be recovered in less than one year after the equipment is operated.

Seventh, conclusion

With the rapid development of power electronics technology and the improvement of frequency conversion technology, more and more frequency conversion speed control systems have been applied to various industries. With their excellent control performance, significant energy saving effects have brought tremendous economic benefits to enterprises.