Which component does NOT typically assist in controlling the flow of refrigerant in a refrigeration system?

The packing valve is not typically involved in controlling the flow of refrigerant within a refrigeration system. Its primary purpose is to prevent leakage in systems such as pumps or compressors by providing a seal at a moving shaft.

In contrast, the other components listed play crucial roles in the management of refrigerant flow. The thermal expansion valve (TXV) is specifically designed to regulate the amount of refrigerant that enters the evaporator, adjusting to changes in load conditions. The receiver acts as a storage vessel for refrigerant, ensuring the system maintains an adequate amount of refrigerant and helps in managing flow to other components. The compressor is essential for moving refrigerant through the system, compressing it to increase pressure and facilitate circulation. Thus, each of those components directly contributes to the regulation of refrigerant flow, while the packing valve's function does not align with this purpose.