Which type of steam trap contains both a piston and a valve?

The impulse trap is characterized by the use of both a piston and a valve, which allows it to operate effectively in handling steam and condensate. This design is advantageous as it can quickly react to changes in pressure and flow conditions. The combination of the piston and valve enables the trap to discharge condensate while preventing steam loss, making it efficient in maintaining optimal steam system performance.

In contrast, thermostatic traps utilize temperature-sensitive elements to open and close, responding to the temperature of the steam and the condensate, while float traps operate based on the level of condensate, using a float mechanism to regulate the discharge. Thermal traps are designed to respond to thermal expansion and contraction, relying solely on temperature changes. Each of these types of traps has its specific applications, but the defining feature of the impulse trap is the dual use of a piston and valve for effective operation.