Risks of Corrosive Media in Process Measurement

Examples of corrosive media include strong acids(hydrochloric acid, sulfuric acid,etc.) strong bases like sodium hydroxide, and salts like sodium chloride. These substances may cause corrosion which weakening or deteriorating material of wetted-part, sensing component or sealing fittings such as O-rings, posing different risks to instrument operations:

Precision loss: Corrosive medium can affect accuracy of a measuring device as it damages integrity of the sensing element or change its properties. For examples, a capacitance sensor may have a reduced accuracy level due to the dielectric layer is penetrated and a pressure gauge dial could give inaccurate reading when corrosive medium react with bourdon component.

Reduced service life: Constant exposure to corrosive medium will facilitate abrasion and degradation of sensor materials, resulting in dramatically decreased operational lifespan. Without proper protection, a measuring device who is expected to have over ten years of lifespan under normal condition may shorten its useful life to less than one year exposing to aggressive medium and ambience. Such tremendous loss of equipment life will lead to more frequent replacement increasing maintenance costs and downtime.

Medium contamination: In some cases, the corrosion of the sensor materials would cause contamination of the medium being measured. This is of great concern particularly in purity-demanding industries such as pharmaceutical or food & beverage industries where corrosion could cause pollution, product quality and safety issues.

Safety risks: When highly aggressive medium or high-pressure system are involved, instrument malfunction caused by corrosion might bring about dangerous situations including leakage or ruptures, posing risks to personnel, equipment and environment. In worst situation, a corroded pressure transmitter in a high pressure H2 gas system could fail, resulting in a leak or even catastrophic blast.