1、 Overview

Wuxi Huadong power station automation instrument factory has more than twenty years of wind pressure measurement device design and development experience, from the first production of DFY series wind pressure measurement device (national patent) in China, to the continuous upgrading of DFY series products, the function from simple wind pressure measurement to wind speed measurement, from a single measurement function to the current intelligent control system. In the same way, we have also carried out more in-depth design and development in the aspect of gas source purification products. The products range from simple air filtration processing to the current devices that use imported PLC intelligent control to process the filtration process. All of them have been devoted to research and development, so that our products are constantly improved and upgraded, and our users are more and more, more and more widely, which has been fully praised by the majority of users.

Dfy type intelligent air source purification device is widely used in the air source control of power plant. At present, it has developed into the third generation (Ⅱ a series) programmable intelligent products. It has the advantages of small size, stability and reliability, and can realize online installation, setting and debugging.

It is well known that whether the compressed air is dry or not will affect the safe and stable operation of the pneumatic control system. After general drying treatment, compressed air still contains certain moisture, which accumulates with time in different seasons in a complex and uncertain relationship. The result of this moisture accumulation is: on the one hand, it affects the safe and normal operation of the gas equipment, and accelerates its damage; on the other hand, it severely corrodes the gas storage, compressor and other equipment, causing a vicious cycle.

Compressed air with water is a common problem in power plants. At present, manual drain valve is generally used for manual drainage or mechanical drain valve is used for drainage. Manual drain valve or mechanical drain valve have the following disadvantages:

(1) Due to the large number and wide range of steam supply / use points, manual inspection and manual drainage of the drain valve are time-consuming and laborious, and it is difficult to judge whether the drain is clean on site.

(2) Mechanical drain valve has large deviation and poor reliability.

(3) Mechanical drain valve is complex in structure, easy to break down and difficult to repair.

(4) Without online monitoring function, it is impossible to realize online monitoring in the central control room and communicate with the computer.

The above problems can be fundamentally solved by using the dfy type intelligent air source purification device of our plant, which provides stable and reliable guarantee for the control and operation of the air source of the power plant.

2、 Main performance features

The dfy type intelligent air source purification device developed by Wuxi Huadong power station automation instrument factory has entered the third generation (IIA Series) programmable intelligent product after several years of use and development in the power plant. The control product is small in volume, reliable in stability and can be installed online. It can effectively solve the problem that the pneumatic actuator or control unit is polluted by water in the instrument compressed air system. The main features are as follows:

(1) The core part of dfy type intelligent air source purification device adopts Schneider series PLC, which completes the control configuration through the upper computer and control program.

(2) Dfy type intelligent air source purification device can modify the control parameters manually or automatically according to the changes of operation conditions and environment to achieve the best drainage efficiency. For example, the drainage time control parameters are automatically modified according to the seasonal changes. It has a good man-machine interface. The action of solenoid valve accumulates and never loses data. According to the use of the filter, the "filter element replacement request" signal is automatically sent out. It has on-site interrupt test function, soft interrupt test function, and the software design reserves local network function.

(3) The dfy type intelligent air source purification device specially strengthens the safety and reliability design, and can operate reliably under the harsh working conditions. Protection level lp65. The software design has on-line self diagnosis (including power loss alarm); the control box is equipped with output test button to facilitate on-site quick inspection of whether the control station and solenoid valve of dfy type intelligent air source purification device work normally. The software control adopts the fuzzy cotltro J strategy: on the one hand, it controls the optimal water yield; on the other hand, it controls the drainage time sequence of each point to ensure the minimum disturbance of the drainage to the pressure of the air source system, so as to ensure the safety, stability and reliability of the pneumatic actuator and / or control unit.

(4) Dfy type intelligent air source purification device adopts standard modular design. The product is divided into single circuit, double circuit and four circuit types according to different purposes, mainly controlling the number of drainage points.

(5) Dfy type intelligent air source purification device allows network connection through RS-485 bus, and can connect up to 31 dfy type intelligent air source purification devices. Each dfy type intelligent air source purification device constitutes a control station on the network, greatly facilitating the management of user equipment.

(6) The field unit can exchange data with any system or equipment that supports RS485 / Modbus protocol after forming a network through RS485 interconnection.

3、 Technical indicators

Power supply: voltage: 165-256v AC frequency: 50Hz ± 10%

Ambient temperature: - 20 ～ 60 ℃

Ambient humidity: 95% RH

Protection grade: IP56

Network interface: RS485 (optional)

Communication protocol: MODBUS

Data saving time: program and data downloaded to PLC are saved permanently

Working medium: compressed air

Medium temperature: - 25-80 ℃

Input and output air source pressure: ≤ 9.9kgf/cm2

Output flow of filter: 8000L / min

Input and output air supply pipeline: Φ 25, Φ 35 (can be determined according to the design requirements)

Filtering accuracy: the filtering accuracy reaches 5 μ m, and the water removal efficiency is not less than 96%

4、 Installation and maintenance

Dfy type intelligent air source purification device can be horizontally placed beside the air source pipeline according to the site conditions. The air inlet and outlet pipes (on the side of the box) are connected by welded movable joints (or metal hoses can be used according to the user's requirements). The filter elements are replaced regularly according to the quality of their own air source to ensure that the air source is unobstructed and the normal operation of the pneumatic equipment in the whole plant is guaranteed.

During the installation, only one way of 220V AC power supply is put into the power terminal in the control box, and the internal control wiring has been connected in the factory, without user connection. Then connect the air inlet and outlet pipelines, turn on the power supply, set the control parameters, and put into use.

5、 System test

During the operation of the system, press the "test" button, the valve 1 will be closed for 5 seconds and then disconnected, the valve 2 will act after 30 seconds, and then disconnected after 5 seconds. You can check whether the PLC and two solenoid valves are normal through the test button.