Which type of flame proving method is commonly used by direct spark ignition controls in chemical processes?

• A. Flame rectification
• B. Infrared detection
• C. Ultraviolet sensing
• D. Thermocouple sensing

Answer: (A)

Verified step by step guidance

1. Understand that flame proving methods are techniques used to detect the presence of a flame in combustion systems to ensure safe operation.
2. Recognize that direct spark ignition controls require a reliable and fast method to confirm that the flame has been established after ignition.
3. Know that flame rectification is a common method used in these systems, which works by detecting the electrical conductivity of the flame between electrodes.
4. Recall that other methods like infrared detection, ultraviolet sensing, and thermocouple sensing are also used in flame detection but are more typical in other types of systems or applications.
5. Conclude that flame rectification is the preferred method for direct spark ignition controls because it provides immediate and reliable flame detection by measuring the rectified current through the flame.