What is a disadvantage of direct-operated regulators?

Direct-operated regulators are designed to maintain a specific output pressure by directly controlling the flow through a valve that responds to pressure changes. One of the notable disadvantages of these regulators is their poor sensitivity. This issue arises because the operation of direct-operated regulators can be influenced by factors like temperature changes or variations in the upstream pressure, which makes them less responsive to small pressure variations.

In practice, this poor sensitivity means that direct-operated regulators may not maintain the output pressure as precisely as needed in applications that require high accuracy. This limits their use in situations where fine control of pressure is essential. In contrast, regulators with more sophisticated designs, such as pilot-operated regulators, can offer better sensitivity and control, making them more suitable for those demanding applications.

While the physical size, limitations to gas service, and need for external connections are important considerations, they are secondary to the primary concern of sensitivity in pressure regulation.