Fully automatic dosing device

 1、 The purpose of the fully automatic dosing device is:

The fully automatic dosing device is mainly used for adjusting the pH value of boiler feedwater, maintaining the pH value of boiler feedwater within a certain range and operating in the optimal state, preventing the imbalance of boiler feedwater pH value and causing acid-base corrosion of boilers and other thermal equipment, enabling the thermal system to work in the optimal state, extending the service life of thermal equipment, and ensuring the long-term stable and safe operation of thermal equipment.     
2、 Characteristics of fully automatic dosing device:
1. Using an intelligent online industrial acidity meter as a detection system, it can continuously and accurately directly reflect the working conditions of the medium.  
2. The intelligent instrument adopts expert system and single-chip technology for regulation, which has strong adaptability, good stability, and can eliminate the phenomenon of large amplitude oscillation in the system.  
3. Adopting frequency conversion speed regulation technology to achieve a wide adjustment range and provide timely protection for the motor to reduce the motor failure rate.  
4. Users can set reasonable parameters based on the actual situation on site

3、 Common specifications for fully automatic dosing devices:

1. One box with two pumps

2. Two boxes with three pumps (two boxes with four pumps)

3. Combination type

4、 Main technical parameters of fully automatic dosing device:
1. Detection instrument: Range 0-14PH output 4-20mA
2. Adjustment instrument: can be set freely according to the on-site working conditions
3. Power requirement: AC three group four wire system 50Hz
4. Environmental temperature: ＜ 45 ℃
5. Sample water temperature: ＞ 20 ℃ ＜ 35 ℃
6. The pressure of the dosing pump is selected based on the system pressure

5、 The working principle of the fully automatic dosing device:
In order to meet the continuous control of the regulated object, the device adopts a closed-loop value adjustment system as shown in the figure

6、 Control process of fully automatic dosing device:
The acidity meter of the fully automatic dosing device detects the pH value of the tested water sample and converts it into a 4-20mA standard signal, which is input to the process controller. The process controller compares its input signal with the given value, performs logical operations according to a certain algorithm based on the comparison result, and outputs the 4-20mA standard signal to the frequency converter in a certain way. The frequency converter changes its output frequency according to the deviation signal to control the speed of the AC motor, achieving the requirement of controlling the dosage of the controlled object, so that the controlled parameter of the controlled object operates in the optimal state.

7、 Installation of dosing and sampling pipes:
The shape and installation of the dosing tube are made of stainless steel pipes with a diameter of 10-15mm. About 10 small holes with a diameter of 2mm are evenly opened around the end of the tube. During installation, the tube is tilted in the opposite direction of the water flow and the centerline of the straw medium tube (a part of the dosing pump's dosing solution is squeezed out from the small holes to increase the uniformity of dosing)
The shape and installation of the sampling tube are made of Φ 20 × 3mm stainless steel tube. The tube is inserted into the medium tube at a slight reverse angle of 3/4D, and several small holes of Φ 3mm are opened at 2/3 of the sampling tube end. This allows for sampling from different directions and increases the representativeness of the sample water. The distance between the dosing device and the sample should be 5-10 meters, depending on the actual situation of each factory. The distance from the sampling point to the pH transmitter should be ≤ 20 meters to shorten the transmission.  
The distance between the sampling port and the dosing port, as well as the distance between the sampling port and the pH transmitter, are far greater than the above requirements. The process controller and design scheme have fully considered the situation and the comparative control can also meet the requirements, but the quality is slightly affected.    

8、 Installation of fully automatic dosing device and control cabinet:
The control cabinet should be selected from clean, bright, and non corrosive gases, away from strong magnetic fields, with a temperature of less than 45 degrees and humidity of less than 85%.  
The fully automatic dosing equipment mainly consists of an automatic dosing device composed of a metering tank (chemical storage tank), a dosing metering pump (dosing pump), an automatic control system, and connecting pipelines. Except for some dosing pipelines, sampling pipelines, and dosing concentration detection instruments, automatic dosing devices are generally installed in a centralized dosing room. The automatic dosing device integrates the metering box, metering pump, and automatic control system, that is, installed on a base. The manufacturing plant completes the equipment procurement, manufacturing, assembly, debugging, and trial operation. Users only need to place the combined automatic dosing device in the dosing room, connect the outlet of the dosing metering pump to the dosing pipeline, the inlet and outlet of the metering box to the inlet pipe, and send the power supply and detection instrument signals of the control cabinet to the control cabinet to start and put it into operation.

 

Related products:

Previous article: Return to List
Next article: PAM dosing device