Valve Selection and Specification Guide

ISBN-13: 9781468466706 / Angielski / Miękka / 2012 / 490 str.

R. Merrick

Opis

Today, people who specify or select valves spend over two-thirds of their time researching literature for information on valve sizing, availability, materials, and standards. This is nonproductive time. Unfortunately, most companies do not have the luxury of a team of experts with the necessary experience and education in all of the different fields that apply to valves. The next best alternative is to understand what valves are and all the things they can do. By definition, valves are devices that stop, start, mix, or change the direction and/or magnitude of the fluid flow, pressure, or its tempera- ture. As a specifier or selector you will have to determine whether the valve is going to be used for flow control, throttling, or for on-off service. Then you will have to determine the cycle life or frequency of their operation. You will discover that valves are classified into three categories: on-off valves, control or regulator valves, and fixed valves such as orifice plate, nozzle, duckbill, rupture disk, blind valve, etc. These valves represent approximately thirty different design configurations. It has been said that if cost and delivery were no problem, anyone of the seven basic valve styles could do the job of any other one. But cost and delivery are very important factors in the real world. So you have to be able to distinguish among these seven styles: ball, butterfly, gate, globe, pinch/ diaphragm, plug, and poppet valves.

Spis treści

A Brief History of Valving.- The Use of Valves.- The Function of Valves.- 1 Valve Design and Specification.- Industry Codes and Standards.- History of Standards.- Materials.- Ratings.- Performance.- Controls.- Valve Material Selection.- Chemical Resistance.- Valve Selections for Common Services.- Valve Specifications and Requirements.- Valve Specifications.- The Relationship of Valves to Piping Specs.- The Influence of Size and Rating.- Construction Details.- 2 Valve Construction.- Block Valves.- Gate Valves.- Plug Valves.- Ball Valves.- Displacement Valves.- Other Block Valves.- Throttling and Control Valves.- Globe Valves.- Butterfly Valves.- Diaphragm Valves.- Other Throttling Valves.- Nonreturn Valves.- Swing Check Valves.- Tilting-Disc Check Valves.- Lift Check Valves.- Split-Disc Check Valves.- Centered Spring Check Valves.- Backflow Preventer Valves.- Other Check Valves.- 3 Operators and Actuators.- Displacement Actuators.- Cylinder Actuators.- Diaphragm Actuators.- Rotary Vane Actuators.- Solenoid Actuators.- Motor Actuators.- Electric Motor Actuators.- Air and Hydraulic Motor Actuators.- Manual Operators.- Handwheel Operators.- Lever and Wrench Operators.- Manual Gear Operators.- Signal Interface.- Positioners.- 4 Valve Procurement.- Bid Development.- Bid Evaluation.- What to Look for in Bids.- 5 Modification, Repair, and Troubleshooting.- Valve Modification.- Valve Repair.- Troubleshooting Valves.- 6 Valve and Actuator Sizing.- Sizing Examples-Manual Valves.- Sizing Examples-Manual or Remote-Actuated Valves.- Suggestions for Further Reading.- Appendix: Codes, Standards, and Specifications.- Glossary of Valve Terms.