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<p><font FACE="Arial" size="4">Water</font></p>

<p><u><font FACE="Arial">Calculation conditions</font></u></p>

<p><small><font FACE="Arial">Water must be in state of liquid with temperature from 0.1 to
373.9 °C, and pressure from 0.001 to 1000 MPa in absolute value. Turbulent flowing is
supposed to occur (Re &gt; 10000). Calculated Kvs value applies to state when cavitation
does not occur.<br>
Following data must be entered for calculation of valve´s Kvs value:<br>
&nbsp;&nbsp;&nbsp; Inlet pressure p1<br>
&nbsp;&nbsp;&nbsp; Outlet pressure p2 or differential pressure dp<br>
&nbsp;&nbsp;&nbsp; Flow Q<br>
&nbsp;&nbsp;&nbsp; Medium temperature t <br>
These input data can be entered simultaneously for three states the calculated valve may
be destined for - e.g. for minimal, nominal and maximal flow. Calculation will be executed
after clicking on &quot;OK&quot; frame on the upper part of panel. Optimal Kvs value is
finally selected for state in which calculated Kv value is maximal. But user may change
the final Kvs value.<br>
Further, an optimal inner DN value of piping must be selected. This DN value must be
selected with respect to the speed of medium flowing inside piping. This speed for
actually selected DN is shown on the screen. In common operation, maximum floe speed of
liquid medium is recommended to be 3m/s but it can be up to 5m/s for short-time operation,
or the valve is used as bypass valve or the piping is used for state of emergency.<br>
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Checking of creation of cavitation is executed standartly for water. This may occur when
steam bubbles create and wane at the valve´s throttling system. This phenomenon is
supposed to occur in valve with multi-step pressure reduction.<br>
&nbsp;&nbsp;&nbsp; p1-p2 &gt;= 0.6(p1-ps).<br>
Then it is recommended to use the valve with throttling system resistant to cavitation,
e.g. valve with perforated plug or with plug and seat with overlay of hard metal, possibly
valve with multi-step pressure reduction.</font></small></p>
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