Mettler toledo

Why is it necessary to measure pH?

  • For products with specific properties. During the production process, it is necessary to adjust the pH so that the product meets the technical requirements. The pH of the product largely determines the properties of the final product.
  • To reduce production costs. If the output in the process at a certain pH increases, this means that production costs at this pH will be lower.
  • To reduce the risk to health and the environment. Some products at a certain pH can be dangerous. To assess the degree of hazard of substances, it is necessary first of all to measure the pH.
  • To comply with regulatory requirements. As stated above, some products may be hazardous. State bodies establish special rules to protect the public from any danger associated with the release of harmful substances.
  • To protect equipment. When in contact with reagents, production equipment may corrode if the pH is out of range. Corrosion shortens the life of the equipment, therefore, in order to avoid premature failure of the production line, the pH level should be monitored.
  • For scientific and research purposes. The pH level is an important characteristic that researchers use when studying chemical or biochemical processes.

How to build a measuring system

1. Sensor selection

METTLER TOLEDO sensors are highly efficient and durable. Nevertheless, the sensor should be selected taking into account the problem being solved and the conditions of its operation.

The main selection criteria:

  • measurement range
  • Operating temperature range
  • Operating pressure
  • Length
  • Measurement error
  • Type of electrical connector
  • Built-in temperature compensation
  • Sanitary Requirements

2. Transmitter selection

A transmitter is a component of the system that ensures its interaction with the user. It converts sensor signals to readings displayed on the screen. In addition, it transfers data to the process control system. Transmitters vary in purpose and capabilities.

The main selection criteria:

  • Functionality, i.e. the presence of a PID controller, digital and analog inputs, outputs, etc.
  • HARTTM, PROFIBUSTM, FOUNDATION fieldbus data transfer protocols
  • Display options
  • Type of connection
  • Power supply
  • Degree of dust and moisture protection
  • Ease of use, e.g. backlight, touch screen, language
  • Explosion protection level

3. Case selection

The housing is designed to install the sensor and ensure its contact with the process environment.

Criterias of choice:

  • Sensor Compatibility
  • Housing design:
    • motionless - for reliable protection of the sensor;
    • retractable - to remove the sensor without stopping the process
  • Wednesday immersion depth
  • Type of installation fittings
  • Media Compatibility
  • Sanitary Requirements

4. The choice of installation fittings

Mounting hardware allows the housing to be attached to a tank, reactor, pipe, or tank.

The main selection criteria:

  • Perpendicular or inclined installation
  • Couplings, flanges, thread size
  • Material

5. Choosing a cleaning and calibration system

EasyCleanTM automated cleaning system extends sensor life and reduces maintenance and consumables.
Criterias of choice:

  • Method of cleaning: blowing with air, washing with water, solutions
  • Applicable Cleaning Products
  • Automatic sensor cleaning and calibration
  • Preset Programs
  • Programming Operations
  • Connectivity to control systems: FOUNDATION fieldbus, PROFIBUS PA

6. Other components

To simplify the maintenance and operation of the measuring system, various optional accessories can be used, such as simulators or polarization sensors.

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