1. Introduction

The ammonia nitrogen water quality online automatic analyzer is a new type of ammonia nitrogen online monitoring instrument developed independently based on magnetic conductivity measurement technology platform, combined with constant temperature optical fiber technology, digestion colorimetric integration technology, etc. The working principle of this product complies with the "HJ/T 536-2009 Determination of Ammonia Nitrogen in Water Quality Salicylic Acid spectrophotometric method", and it has the characteristics of high reliability, low lower limit of quantification, and good stability. It can be widely used in groundwater, surface water, domestic sewage, industrial production processes, municipal sewage and other fields.

2. Technical principles

This instrument uses salicylic acid spectrophotometry to measure the ammonia nitrogen content in water samples. In an alkaline medium (pH=11.7) and in the presence of sodium ferrocyanide, the water sample, salicylate, and sodium dichloroisocyanurate color at 50 ℃, reacting to form a blue compound corresponding to the ammonium ion in the water sample. The instrument obtains the ammonia nitrogen value of the water sample through colorimetric measurement.The interference of cations such as calcium and magnesium in water samples can be masked by adding potassium sodium tartrate. If the color of the water sample is too dark, the salt content is too high, the masking ability of potassium sodium tartrate for metal ions in the water sample is insufficient, or there are high concentrations of calcium, magnesium, and chloride in the water sample, pre distillation is required.

3. Main features

1) The instrument adopts a 7-inch 1024 * 600 touch screen and uses the Android operating system, with a more beautiful interface and smoother operation;

2) The use of a patented magnetic conductivity quantification method to quantify samples/reagents fundamentally solves the interference of color turbidity, greatly improving the accuracy and reliability of quantification;

3) The single channel integrated distribution valve island reduces the impact of dead volume on quantitative accuracy, and can be disassembled, cleaned, and replaced in a single channel with low maintenance and cost;

4) The sample developed color at a temperature of 50 ℃, greatly improving the reaction efficiency;

5) The color development system has comprehensive protection functions, which can effectively prevent possible leakage and other situations;

6) According to the actual situation, the color development temperature and time can be adjusted to ensure sufficient reaction;

7) The instrument has multiple built-in ranges, and can automatically adjust the range according to the ammonia nitrogen content of the water sample, making the measurement more accurate;

8) The instrument can automatically achieve calibration, cleaning and other functions without user intervention, avoiding measurement errors;

9) When the instrument malfunctions, it has self inspection and maintenance functions to ensure personal safety and equipment safety;

10) When a liquid leak occurs, the device's built-in humidity sensor will sound an alarm and automatically lock;

11) All fault information is recorded at the HMI display terminal, allowing users to query and have a clear understanding of the equipment's operating status;

12) The instrument can be extended with remote upgrade function, and remote maintenance and monitoring of equipment can be achieved through Ethernet port, GPRS port, etc;

13) The instrument has rich external interfaces, and various interfaces used on site (such as Ethernet/(4-20) mA input, output/RS485/switch input, output, etc.) are available;

14) The instrument has good scalability, allowing for the addition of device functions according to user needs.

5. Main technical indicators

1) Measurement method: Salicylic acid spectrophotometric method;

2) Measurement range: 0-2/10/100mg/L (expandable);

3) Interference substances: mainly calcium and magnesium ions, please contact the manufacturer for details;

4) Zero drift: ≤ 0.02mg/L;

5) Range drift: ≤ 1%;

6) Repeatability: ≤ 2%;

7) Indication error: ± 8%;

8) Voltage stability: not exceeding ± 10%;

9) Mean time between failures and continuous operation: ≥ 720h/time;

10) Measurement interval: hourly measurement, interval time measurement, and instrument can also be triggered through Modbus;

11) Calibration: Supports manual and automatic calibration. Calibration cycle and time can be set;

12) Temperature for operation and storage: (5-40) ℃, humidity: (65 ± 20)%, no condensation;

13) Power supply and output: (220 ± 22) VAC, (50 ± 0.5) Hz, 200W;

14) Signal output: 1 channel (4-20) mA (expandable to 2 channels), RS232/RS485， 4 multifunctional relays;

15) Signal input: 1 channel (4-20) mA (expandable to 2 channels). 4-channel switch quantity;

16) User maintenance: A single set of reagents can measure 400 samples;

17) Preheating time: 2 hours;

18) Other functions: automatic cleaning, data recording, printing (optional);

19) Instrument size (mm): 500 * 405 * 1400 (excluding wheel height);

20) Instrument weight (kg): 75;

21) Packaging weight (kg): 90.