Valve Selection Crucial in System Design

Many factors influence the selection of valves and process tubes in refrigeration and air-conditioning systems

Manufacturers and designers of air-conditioning, refrigeration, and heat-pump systems must determine the process that will be used for evacuation, charging, and run testing their systems. Valves and process tubes provide the necessary access to the system, but before implementing a solution users must consider the factors specific to each application, including ease-of-use, flow rate, leak rate, cost, and field-service requirements.

Within heating, piping, and air-conditioning applications, there are several commonly used methods for introducing air, liquids, and gas into the system. Options include the Schrader-style valve, high-flow valves, process tubing paired with connectors, and a valve quick-connection system. By understanding how each solution works and its benefits and limitations, users can make informed decisions about the option that best complements their specific requirements.

In addition to evacuating and charging air-conditioning and refrigeration systems, valves are used for evacuating and charging numerous other systems, including chillers. Additionally, valves are used in the manufacturing process of heat pumps to draw a deep vacuum on all units to pull out contaminants that would affect the quality of products.

Sleeve-activated connectors on a split system.

Schrader-style valves can be used for this purpose; however, they are subject to low flow rates, which may be problematic when efficiency is key—especially because multiple stages of evacuation may be required along a production line. Although a special connector can be used to fill and evacuate the systems directly through a straight tube and eliminate the valve restriction, the extra station for pinching and brazing at the end of an assembly line requires additional time and expense and increases the possibility of leaks. Valve quick-connection solutions solve both of these limitations, allowing high flow rates without the extra pinching and brazing requirements.

Another application example is found in the manufacturing process of split-system air-conditioning units. For charging, evacuating, pressure testing, or vacuum testing these systems, connectors can be used in the place of the Schrader on the service valve. Options such as internal lever-action connectors provide reliable connections and feature ports that allow process mediums to be introduced directly through the service valves. These connectors feature a safety design and pressure-assisted gripping collets that prevent accidental disconnects during high-pressure applications.

Proper processing selection for these and other applications relies on multiple factors, and by understanding the advantages and limitations of each valve, users can select a solution that will offer the appropriate performance capabilities while meeting the necessary cost and maintenance requirements.