Note For questions 1 through 4 use the pressure regulator sp

Note: For questions 1 through 4 use the pressure regulator specification sheets in Tables 1 and 2 to answer the questions. In al cases the design flow is 10% offset (droop) 1. What is the best regulator to use when a pressure-reducing regulator set at 10 psig and using 100 psig air supply is used to purge a header with 20 scfm of air when an air operated valve is opened? Part 10 SET AT 10 PSIG ON/OFF VALVE 20 SCFM HEADER AIR (100 PSIG)

Solution

Inlet pressure = 100 psig.

Pressure reducing regulator set = 10psig.

Air flow rate = 20 SCFM = 1200 SCFH.

From the table, @ 100 psig inlet pressure and outlet setting 10 psig,

3/4 in regulator body size and at 10% offset should be chosen.

Here the on-off valve partial opening will reduce the flow from

6400 SCFH to 1200 SCFM.