How to choose the right pH sensors?

In various chemical environments, pH sensors play a key role in ensuring process stability and product quality. However, when choosing the right pH sensor for your application, it's important to consider several factors as different pH sensor designs are suitable for different environments such as aqueous solutions, corrosive liquids, or high-temperature processes. Let's explore how to select the most suitable pH sensor for your needs.

1. pH Range

Ensure that the pH sensor's measurement range aligns with the pH levels expected in your process. Dongguan Daxin's pH sensors cover a wide pH range, making them suitable for various applications

2. Chemical Compatibility

Evaluate the compatibility of sensor materials with chemicals present in your process. Glass shell pH sensors exhibit stronger corrosion resistance and acid-base tolerance, making them suitable for a wider range of applications.

3. Temperature Range

Check the pH sensor's temperature range to ensure it can withstand the temperatures encountered during your process. High-temperature pH sensors are designed to operate within a wide temperature range, providing flexibility for various industrial environments. Some electrodes can withstand high-temperature steam sterilization. Daxin's DX-250 is specifically designed for high-temperature environments, with a sterilization temperature of up to 130°C.

4. Shell Material

Consider the material of the sensor's main shaft. Glass and epoxy resin are commonly used materials. Glass electrodes are typically used for samples containing proteins, organic compounds, solvents, or epoxy resin bodies. Epoxy resin electrodes are often more economical and durable and can be used in situations where the medium may erode and etch glass. Glass can withstand higher temperatures. For industrial applications, the use of polyphenylene sulfide (PPS) is preferred due to its excellent dimensional stability and ability to withstand prolonged high temperatures. It also has inherent flame retardancy and chemical resistance comparable to PEEK and fluoropolymers.

5. Liquid Junction

This part of the probe establishes electrical contact between the reference solution and the sample solution. Various materials are used for connection; ceramics are the most common due to their low leakage rate, suitable for liquid-filled sensors. Polytetrafluoroethylene (PTFE) is another easy-to-handle and clean option.

6. Temperature Compensation

Many sensors offer the option to integrate a temperature sensor into the electrode. Since pH value depends on temperature, accurate measurements require temperature compensation to ensure precision. Many instruments also provide manual temperature compensation or offer a separate temperature probe (non-integrated).

7. Sensor Size

Daxin's glass pH sensors have standard dimensions of 120mm shaft length and 12mm outer diameter; standard dimensions for shell pH sensors are 127mm shaft length and 29mm outer diameter. Sensors come in various shapes and sizes, so considering physical requirements such as electrode thread size and immersion depth is essential when selecting a pH electrode for your application.

8. Cable Length

Most laboratory-grade sensors come with a standard 1-meter cable, while industrial electrodes come with a 5-meter cable. This can be customized as per requirements.

9. Connector Type

The connector type depends on the instrument to which the pH electrode will be connected. The most common connector type is BNC, but most instruments can also use many other types of connectors, such as pin, Y-type connectors.

10. Thread Size

pH sensor threads are divided into two types, PG13.5 for glass pH sensors, and 3/4” NPT for shell pH sensors. We can also provide PTFE or stainless steel protective sleeves for glass pH sensors, with a thread size of 3/4” NPT.

Dongguan Daxin's pH sensors offer a variety of designs and functionalities to meet the needs of different industries and environments. Whether your application is in a laboratory or on an industrial production line, our professional team will provide you with customized solutions to ensure accurate and reliable pH measurements.