What is the primary function of an orifice plate in a refrigeration system?

The primary function of an orifice plate in a refrigeration system is to serve as a passive throttling device that controls the flow of refrigerant. An orifice plate creates a restriction in the flow path, which causes a pressure drop as the refrigerant passes through it. This pressure drop is essential for regulating the flow rate of the refrigerant entering the evaporator, allowing the system to maintain the desired operational conditions.

In this role, the orifice plate helps manage the amount of refrigerant that can enter the evaporator, ensuring efficient heat exchange and optimal system performance. It is not an active control component, as it does not adjust the flow dynamically but rather provides a constant restriction based on its size and configuration.

The other options relate to functions that do not accurately describe the role of an orifice plate. For example, while evaporator pressure can be influenced by various factors, an orifice plate does not actively control it. Additionally, measuring refrigerant temperature is typically the role of temperature sensors, and safety features to prevent system overpressure would involve devices like pressure relief valves, rather than an orifice plate.