boiler

How does PRDS work. what is other ways for reducing pr. in steam line.

You mean PRV? Just one word PRV means "Pressure Reducing Valve" and there cannot be then "ways" but "Types". Question first - Do you know steam? If yes, then pick up any PRV catalog of any manufacturer and they will detail you how they work.

Suggest you go to your local library and pick up all books on Boilers, read and do your own assignments.

All your Boiler questions are falling in a pattern that either you are totally new with boilers or come across a book already and fished out all these questions.

Prior answering all your questions but first I want you to email me your CV with educational & job description to assure that you are in this job.