RE: purpose of check valve

From: <Erik>
Date: Wed Nov 30 2005 - 10:49:00 EST

As far as I know there are no check valves who closes before flow reverse. An ideal check valve would close at zero flow (working like a diode).

But ideal does no exist, so check valves always closes at return flow. The fast a check valve closes, the best it is with respect to waterhammer.

If you know such check valves please let me know the type and the manufacturer.

Erik.

---

Van: <a href="/group/PipingDesign/post?postID=IW1zEyCaZPdDadhQ8gFJkXjOlnI4JemW_OmxtHxZ2tzPtSNeDRkqZN6mPQpnovm20HcDo_lhRaWrifk7jf4NE1HoLw">PipingDesign@yahoogroups.com</a> [mailto:<a href="/group/PipingDesign/post?postID=IW1zEyCaZPdDadhQ8gFJkXjOlnI4JemW_OmxtHxZ2tzPtSNeDRkqZN6mPQpnovm20HcDo_lhRaWrifk7jf4NE1HoLw">PipingDesign@yahoogroups.com</a>] Namens r_ravoori
Verzonden: Saturday, November 26, 2005 4:54 PM Aan: <a href="/group/PipingDesign/post?postID=IW1zEyCaZPdDadhQ8gFJkXjOlnI4JemW_OmxtHxZ2tzPtSNeDRkqZN6mPQpnovm20HcDo_lhRaWrifk7jf4NE1HoLw">PipingDesign@yahoogroups.com</a> Onderwerp: [PipingDesign] purpose of check valve

Apart from back-flow prevention, there are other uses: 1) Spring loaded or 'silent' check valves assist in minimizing water hammer effects by the fast closure of the valve before flow reverses. 2) There are other specialized check valves used in steam extraction lines from turbines. These are power-assisted and prevent water from entering the turbine.
R.V.Ramachandran

---

PipingOffice - Excel Spreadsheets for Piping Calculations
<a href="http://www.pipingoffice.us/">http://www.pipingoffice.us/</a>

---

Main site: <a href="http://www.pipingdesign.com">http://www.pipingdesign.com</a>

SPONSORED LINKS Mechanical
<<a href="http://groups.yahoo.com/gads?t=ms&k=Mechanical+engineering&w1=Mechanical+en">http://groups.yahoo.com/gads?t=ms&k=Mechanical+engineering&w1=Mechanical+en</a>
gineering&w2=Mechanical+engineering+jobs&w3=Cad+drafter&w4=Process+piping&w5 =Mechanical&c=5&s=114&.sig=qAVe0S3R007ZZC_VnrxgVg> engineering

Mechanical
<<a href="http://groups.yahoo.com/gads?t=ms&k=Mechanical+engineering+jobs&w1=Mechanic">http://groups.yahoo.com/gads?t=ms&k=Mechanical+engineering+jobs&w1=Mechanic</a>
al+engineering&w2=Mechanical+engineering+jobs&w3=Cad+drafter&w4=Process+pipi ng&w5=Mechanical&c=5&s=114&.sig=S1FagOodk-Cf2O2QKteRYA> engineering jobs

Cad
<<a href="http://groups.yahoo.com/gads?t=ms&k=Cad+drafter&w1=Mechanical+engineering&w">http://groups.yahoo.com/gads?t=ms&k=Cad+drafter&w1=Mechanical+engineering&w</a>
2=Mechanical+engineering+jobs&w3=Cad+drafter&w4=Process+piping&w5=Mechanical &c=5&s=114&.sig=ur1Tv66FPjPyv-uCBKRtWg> drafter

Process
<<a href="http://groups.yahoo.com/gads?t=ms&k=Process+piping&w1=Mechanical+engineerin">http://groups.yahoo.com/gads?t=ms&k=Process+piping&w1=Mechanical+engineerin</a>
g&w2=Mechanical+engineering+jobs&w3=Cad+drafter&w4=Process+piping&w5=Mechani cal&c=5&s=114&.sig=FzWvo5YxfZDmFBVlwyPf1w> piping

Mechanical
<<a href="http://groups.yahoo.com/gads?t=ms&k=Mechanical&w1=Mechanical+engineering&w2">http://groups.yahoo.com/gads?t=ms&k=Mechanical&w1=Mechanical+engineering&w2</a>
=Mechanical+engineering+jobs&w3=Cad+drafter&w4=Process+piping&w5=Mechanical& c=5&s=114&.sig=68oR4NLxc8ihQjBusA_H3Q>

---

YAHOO! GROUPS LINKS

• Visit your group "PipingDesign
  <http://groups.yahoo.com/group/PipingDesign> " on the web.
  
• To unsubscribe from this group, send an email to: <a href="/group/PipingDesign/post?postID=SSQb9ad1Veq9tD8oxVeO3YQAPnA6411VTu_isnxyO1uc1zIflf--GcvUWI_KyHy2d0p6-t6vvK3cxRjKdiIyuAgGIWtpvGh84pOSYvDcajIaag">PipingDesign-unsubscribe@yahoogroups.com</a>
  <mailto:PipingDesign-unsubscribe@yahoogroups.com?subject=Unsubscribe>
  
• Your use of Yahoo! Groups is subject to the Yahoo!
  <http://docs.yahoo.com/info/terms/> Terms of Service.
  

  ---

[Non-text portions of this message have been removed] Received on Wed Nov 30 10:49:00 2005