Page 12 - Valve Selection Handbook
P. 12

PREFACE












             Valves are the controlling elements in fluid  flow  and pressure  systems.
           Like  many  other  engineering  components,  they  have  developed  over
           some  three  centuries  from  primitive  arrangements  into  a  wide  range of
           engineered units satisfying  a great variety of industrial needs.
             The  wide  range  of  valve  types  available  is  gratifying to  the  user
           because  the probability is high that a valve exists that matches the appli-
           cation.  But  because  of  the  apparently  innumerable alternatives,  the user
           must have the knowledge and skill to analyze each application  and deter-
           mine the factors on which the valve can be  selected.  He or she must also
           have  sufficient  knowledge  of  valve types  and their construction to make
           the best selection  from  those available.
             Reference  manuals  on  valves  are readily  available.  But  few  books, if
           any,  discuss  the  engineering  fundamentals  or  provide  in-depth informa-
           tion about the factors on which the selection  should be made.
             This book  is the result of a lifelong study of design  and  application of
           valves,  and  it  guides  the  user  on  the  selection  of  valves  by analyzing
           valve use and construction. The book  is meant to be a reference for prac-
           ticing  engineers  and  students, but  it  may  also be  of  interest  to  manufac-
           turers  of  valves,  statutory  authorities,  and  others.  The  book  discusses
           manual valves, check valves, pressure relief valves and rupture discs.
             Revisions in  the  fourth  edition  include  a  full  rewriting of the  chapters
           on  pressure  relief  valves  and  rupture  discs.  These  revisions  take  full
           account  of current U.S. practice and the emerging European  standards.
             I  wish to  express  my  thanks to  the  numerous individuals  and  compa-
           nies  who  over  the  years  freely  offered  their  advice  and  gave  permission


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