Online PH Meter _ Online ORP Meter

Overview

Industrial online pH meter - Online ORP meter is a water quality online monitoring instrument with a microprocessor. The online pH/ORP meter is equipped with different types of pH (or ORP) electrodes, which are widely used in various industries such as power plants, petrochemicals, metallurgical electronics, mining, papermaking, biological fermentation processes, pharmaceuticals, food and beverage, environmental water treatment, etc. It continuously monitors and controls the pH (acidity and alkalinity) value or ORP (oxidation-reduction potential) value and temperature value of aqueous solutions. Online pH/ORP meters are used for power plant feedwater, saturated water, condensate water, general industrial water, domestic water, and wastewater.

The online pH/ORP meter adopts an LCD liquid crystal display screen; Intelligent Chinese menu operation; Equipped with current output, freely adjustable measurement range, high and low limit alarm prompts, and two sets of relay control switches, with adjustable delay range; Automatic or manual temperature compensation; Multiple automatic calibration methods for electrodes.

According to user needs, pH (or ORP) electrodes can be installed in various forms such as flow type, sinking type, pipeline type, flange type, etc.

II. Structural Features and Working Principles

2.1 Structural Features:

The complete measurement system of online pH meter and online ORP meter mainly consists of two parts: the instrument (secondary instrument) and the pH (or ORP) electrode (primary instrument). The pH (or ORP) electrode contacts the measured aqueous solution, and the instrument displays the pH (or ORP) value, temperature value, and working status of the aqueous solution.

2.2 Working principle:

The instrument consists of signal measurement, operation, display, network communication, and panel instructions. The impedance transformation of pH and temperature transmission changes the pH to a low impedance signal of 59.16mV/pH (25 ℃); Convert NTC into a voltage signal.

The instrument is matched with a pH (or ORP) electrode to monitor the pH (or ORP) value of the solution. The sensor is a battery composed of a pH (or ORP) glass electrode and a calomel (or Ag/AgCl) reference electrode, which generates a potential difference related to the pH value of the solution based on the Nernst equation: Ex=Eo+SpH.

The potential difference is amplified by a preamplifier with high input impedance, and the thermistor sends out a signal corresponding to the temperature value. After amplification, the two sets of signals are converted from A/D and processed by an I/O interface chip through a single-chip microprocessor before being prominently displayed on the display screen.

Three technical parameters

(1) Measurement range: pH: 0.01-14.00pH; ORP：－1999～＋1999mV；

Temperature: -5~110.0 ℃;

（2）分辨率： pH：0.01pH； ORP：1mV；

(3) Basic error: pH: ± 0.1pH; ORP: ± 3mV; Temperature: ± 0.5 ℃;

(4) Automatic or manual temperature compensation range: 0-110 ℃;

(5) Stability: pH: ≤ 0.02pH/24h; ORP: ≤2mV/24h；

(6) Signal output:

0-10mA (load resistance<1.5K Ω); 4-20mA (load resistance<750 Ω);

Optional: 0-5V, 0-10V (pre order required);

(7) Two sets of relay control contacts: 3A 240VAC, 6A 28VDC or 120VAC;

(8) Power supply: 220VAC ± 10%, 50 ± 1Hz, power ≤ 3W;

24VDC， Power ≤ 1W (to be reserved); 12VDC， Power ≤ 1W (to be reserved);

(9) Dimensions: 96 × 96 × 130mm;

(10) Installation method: disk mounted (embedded); Hole size: 91 × 91mm;

(11) Wall mounted: Waterproof wall mounted box size: 300 (height) x 200 (width) x 167 (depth) mm;

(12) Instrument weight: 0.6kg;

(13) Work environment:

Environmental temperature: -10~60 ℃;

Relative humidity: not exceeding 90%;

There is no strong magnetic field interference around except for the Earth's magnetic field.