There is a model of steam trap that has a built-in bypass Valves.
To use this trap, at start-up open the bypass valve to rapidly discharge the start-up condensate. Then during normal operation, leave the bypass valve closed so condensate is discharged only through the trap. However, keep in mind that because this bypass valve is built into the trap, it cannot perform the bypass function when the trap is in the process of being replaced. To our knowledge, there are no Control Valves or pressure reducing valves with built-in bypass features. They must be used in combination with suitable valves.