Terminology B. Types of Devices

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" colspan=2 height=90 BGCOLOR="#000066" TEXT="#F7F7FF" bgproperties="fixed" background="66b00c10dkbliw.jpg"> <div> <FONT SIZE="2" COLOR="#FF6600" FACE="Arial" ><A HREF="index.htm" TARGET="_top" TITLE="PRD Technologies Inc."><U><B>HOME </B></U></A><B> </B></FONT><B>   </B><A HREF="id151.htm" TARGET="_top" TITLE="Pressure Relief Device Terminology"><U><B> </B></U></A><FONT SIZE="2" COLOR="#FF6600" FACE="Arial" ><A HREF="id151.htm" TARGET="_top" TITLE="Pressure Relief Device Terminology"><U><B> BACK </B></U></A></FONT><A HREF="id151.htm" TARGET="_top" TITLE="Pressure Relief Device Terminology"><U><B> </B></U></A><B>|  </B><FONT SIZE="7" COLOR="#FF6600" FACE="Arial" ><B> </B></FONT><FONT SIZE="7" COLOR="#FFFFCC" FACE="Arial" ><B>  </B></FONT><FONT SIZE="6" COLOR="#FFFFFF" FACE="Arial" ><B>PRD Technologies Inc.</B></FONT></div> <bR> <div> </div> </td> </tr><tr> <td valign="top" width=210 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> Terminology B. Types of Devices</div> <bR> <div> <B><IMG SRC="41a9b3e0.png" border=0 width="155" height="62" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></div> <bR> <div> <B><IMG SRC="25a80500.jpg" border=0 width="128" height="80" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></div> <div> <B><IMG SRC="57482420.jpg" border=0 width="130" height="66" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></div> </td> <td valign="top" height=390 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> <I><B> Pressure Relief Solutions & Services</B></I></div> <div> <B>B. Types of Devices</B></div> <bR> <div> <B>B.1 Reclosing Pressure Relief Devices</B></div> <bR> <div> <I><B>(a) Pressure Relief Valve</B></I><B>. </B>A pressure relief valve is a spring loaded pressure relief device which is de-signed to open to relieve excess pressure and to reclose and prevent the further flow of fluid after normal conditions have been restored. It is characterized by</div> <div> rapid opening pop action or by opening generally proportional to the increase in pressure over the open-ing pressure. It may be used for either compressible or incompressible fluids, depending on design, adjust-ment, or application.</div> <div> <I><B>(b) Safety Valve. </B></I>A safety valve is a pressure relief valve actuated by inlet static pressure and character-ized by rapid opening or pop action. (It is normallyused for steam and air services.)</div> <div> <I><B>(1) Low-Lift Safety Valve. </B></I>A low-lift safety valve is a safety valve in which the disc lifts automaticallysuch that the actual discharge area is determined by the position of the disc.</div> <div> <B>(</B><I><B>2) Full-Lift Safety Valve. </B></I>A full-lift safety valve is a safety valve in which the disc lifts automaticallysuch that the actual discharge area is not deter-mined by the position of the disc.</div> <div> <I><B>(c) Relief Valve. </B></I>A relief valve is a pressure relief device actuated by inlet static pressure having a gradual lift generally proportional to the increase in pressure over opening pressure. It may be provided with an enclosed spring housing suitable for closed discharge system application and is primarily used for liquid service.</div> <div> <I><B>(d) Safety Relief Valve</B></I><B>. </B>A safety relief valve is a pressure relief valve characterized by rapid opening or pop action, or by opening in proportion to the increase in pressure over the opening pressure,depending on the application and may be used either for liquid or compressible fluid.</div> <bR> <div> <I><B>(1) Conventional Safety Relief Valve. </B></I>A conven-tional safety relief valve is a pressure relief valve which has its spring housing vented to the discharge side of the valve. The operational characteristics(opening pressure, closing pressure, and relieving</div> <div> capacity) are directly affected by changes of the back pressure on the valve.</div> <div> <I><B>(2) Balanced Safety Relief Valve. </B></I>A balanced safety relief valve is a pressure relief valve which incorporates means of minimizing the effect of back pressure on the operational characteristics (opening pressure,closing pressure, and relieving capacity).</div> <bR> <div> <I><B> (e) Pilot-Operated Pressure Relief Valve</B></I><B>. </B>A pilot-operated pressure relief valve is a pressure relief valvein which the major relieving device is combined with and is controlled by a self-actuated auxiliary pressure relief valve.</div> <div> <I><B>(f) Power-Actuated Pressure Relief Valve. </B></I>A power-actuated pressure relief valve is a pressure relief valve in which the major relieving device is combined with and controlled by a device requiring an external source of energy.</div> <div> <B>(</B><I><B>g) Temperature-Actuated Pressure Relief Valve. </B></I>A temperature-actuated pressure relief valve is a pres-sure relief valve which may be actuated by external or internal temperature or by pressure on the inlet side. </div> <div> <I><B>(h) Vacuum Relief Valve. </B></I>A vacuum relief valve is a pressure relief device designed to admit fluid to pre-vent an excessive internal vacuum; it is designed to reclose and prevent further flow of fluid after normal conditions have been restored.</div> <div> <B>B.2 </B><I><B>Non-Reclosing Pressure Relief Devices</B></I><B>. </B>A non-reclosing pressure relief device is a pressure relief device designed to remain open after operation. A manual resetting means may be provided.</div> <div> <I><B>(a) Rupture Disc Device</B></I><I>. </I>A rupture disc device is a non-reclosing pressure relief device actuated by inlet static pressure and designed to function by the burst-ing of a pressure containing disc.</div> <div> <I><B>(b) Breaking Pin Device. </B></I>A breaking pin device is a non-reclosing pressure relief device actuated by inlet static pressure and designed to function by the break-age of a load-carrying section of a pin which supports a pressure containing member.</div> <bR> <bR> <div> <B>For further assistance or information call (330) 253-4800or email: </B><A HREF="mailto:sales@prdtechnologies.com" TARGET="_top" TITLE="mailto:sales@prdtechnologies.com"><U><B>sales@prdtechnologies.com</B></U></A><A HREF="mailto:sales@prdtechnologies.com" TARGET="_top" TITLE="mailto:sales@prdtechnologies.com"><U> </U></A> </div> </td> </tr></table></body>