tailieunhanh - Ebook Boiler operators handbook: Part 2

(BQ) Part 2 book "Boiler operators handbook" has contents: Plants and equipment (heat transfer in boilers, circulation, circulation, vatertube boilers, fans and blowers,.), controls, why they fail. | Plants and Equipment 195 Chapter 9 Plants and Equipment I t would take volumes of books to adequately describe all the variations of design and construction in boilers since Hero first produced steam under (a little) pressure. And that’s only boilers, nothing to do with all the other plant equipment and systems. You may encounter a design that isn’t described in this section. I encountered two true Sterling design boilers, an 1890 design constructed in 1952, only two months ago. I’ve limited the descriptions in this section to what you would normally encounter. If you do encounter an older design it should be described in one of the references listed in the bibliography. TYPES OF BOILER PLANTS When you want to get a definition right you go to the source and, in the case of boilers, the source is ASME, the American Society of Mechanical Engineers which produced and maintains its Boiler and Pressure Vessel Code (BPVC). The code is the accepted rule for construction of boilers and pressure vessels in the United States, Canada, and much of the world. According to the code a boiler is a vessel in which a liquid is heated or a vapor is generated under pressure by application of heat from the products or combustion or another source. Vessel is the code word for an enclosed container under pressure. Now let’s get the meaning of pressure straight. You’ll encounter a large number of people in your career that have their own idea of what is low pressure and high pressure then we all get to disagree on what we mean when we say medium pressure. The BPVC in its various documents defines high pressure and low pressure but never addresses the term medium pressure. High pressure boilers are defined by ASME in the first document prepared to address the construction of boilers and pressure vessels which is now known as Section I of the BPVC and it’s simply titled “Rules for Construction of Power Boilers.” That is a roman numeral one, not a capital letter i. All sections of the