tag:blogger.com,1999:blog-28773952.post7098192352328963691..comments2017-05-18T15:37:21.143+05:30Comments on Chemical Professionals: Equal Percentage Valves - Opening Vs FlowTechnologisthttp://www.blogger.com/profile/06755052660465083010noreply@blogger.comBlogger13125tag:blogger.com,1999:blog-28773952.post-24509006784988597662016-02-15T18:54:16.041+05:302016-02-15T18:54:16.041+05:30Either, I do not understand your explanation of th...Either, I do not understand your explanation of the Equal Percentage curve, or I do not agree. Let me give you an example: The valve is fully open, thus valve lift is 100% and valve flow is 100%, right? Then I reduce the valve lift to 90%, changing it by -10%. Then according to your explanation (as I understand it), the flow should be 100%-10% = 90% of maximum flow. However this is not right, and it is fairly obvious to see from the curve you are using, where the flow at 90% valve lift is approximately 70% of maximum flow. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-28773952.post-56562739312047502632013-10-24T14:08:46.414+05:302013-10-24T14:08:46.414+05:30I Really appreciate, this has been defined very cl...I Really appreciate, this has been defined very clearly by simple example R. Kannannoreply@blogger.comtag:blogger.com,1999:blog-28773952.post-90846554432601421402013-06-13T02:44:13.985+05:302013-06-13T02:44:13.985+05:30for all equal-percentage control valves, the gener...for all equal-percentage control valves, the general equation is:<br /><br />% max flow (or % max Cv) = 100/T*exp(H*ln(T))<br /><br />where T = valve rangeability or turndown (typically 50 for globe type)<br />H = % valve open/lift (75% would be inputted as 0.75)<br /><br />so if you are using a globe valve, the above equation reduces to:<br /><br />% max flow = 2*exp(H*ln(50))<br /><br />if you plot this against the equation given in the post, they produce similar results.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-28773952.post-35107736914447564652013-03-03T20:43:38.391+05:302013-03-03T20:43:38.391+05:30-0.00000502*X^4
and the result is OK-0.00000502*X^4 <br /><br />and the result is OKIrfan Qadirnoreply@blogger.comtag:blogger.com,1999:blog-28773952.post-84037384460492186162011-04-20T12:52:51.229+05:302011-04-20T12:52:51.229+05:30First of all, thx for your great post.
Anyone loo...First of all, thx for your great post.<br /><br />Anyone looking for chemical? <br />I have a recomendation for all of you where KLH Chemical Sdn Bhd is a chemical company in malaysia. KLH offer all kind of chemical such as acids, caustic soda. Feel free to visit to the website at http://www.klhchem.com.my to have more information.jaze foohttp://www.klhchem.com.mynoreply@blogger.comtag:blogger.com,1999:blog-28773952.post-18660336194698510422010-05-03T18:57:44.060+05:302010-05-03T18:57:44.060+05:30I added the extra zero in the fifth term as omkran...I added the extra zero in the fifth term as omkranthi1 recommends (-0.00000502*X^4) and the result comes out within +/- 1% at 0 and 100% stem positions. Looks like a simple mistake with the post. Thanks for the equal percentage characteristic.Engineer 55noreply@blogger.comtag:blogger.com,1999:blog-28773952.post-82107937112381937182010-05-03T18:50:02.528+05:302010-05-03T18:50:02.528+05:30I also ran this calculation in Excel and got the s...I also ran this calculation in Excel and got the same result (at 60%) as "Anonymous": -562.714 Back to the google searching....Engineer 55noreply@blogger.comtag:blogger.com,1999:blog-28773952.post-78050459634810786152009-12-20T19:02:18.629+05:302009-12-20T19:02:18.629+05:30Hey,let my valve opening initially is 0% ie closed...Hey,let my valve opening initially is 0% ie closed,now the command goes to open,say it is 1%,then what will be the %flow???????vishalhttp://www.blogger.com/profile/02323664033902811237noreply@blogger.comtag:blogger.com,1999:blog-28773952.post-26072435600816953582009-07-15T20:26:38.443+05:302009-07-15T20:26:38.443+05:30Dear
Did you use 0.6 for 60% or 60 in the equation...Dear<br />Did you use 0.6 for 60% or 60 in the equation.profmasterhttp://www.blogger.com/profile/06755052660465083010noreply@blogger.comtag:blogger.com,1999:blog-28773952.post-15693563055092622352009-07-11T14:04:56.194+05:302009-07-11T14:04:56.194+05:30something wrong somewhere... I try and put it in E...something wrong somewhere... I try and put it in Excel but produce some bizzare result, e.g. 60% lift produce %flow = -562,714!<br /><br />Anyone tried it out?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-28773952.post-45624018632426561532009-06-03T18:43:21.370+05:302009-06-03T18:43:21.370+05:30its wrong i can prove itits wrong i can prove itAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-28773952.post-13084570062667069222009-05-29T11:19:35.270+05:302009-05-29T11:19:35.270+05:30i appreciate it for sharing the info. great post. ...i appreciate it for sharing the info. great post. great blog.gate valveshttp://www.meaincorporated.comnoreply@blogger.comtag:blogger.com,1999:blog-28773952.post-54223647486592787602009-01-04T08:25:00.000+05:302009-01-04T08:25:00.000+05:30Hi,There is a zero missing in the 5 th term isn't?...Hi,<BR/><BR/>There is a zero missing in the 5 th term isn't?omkranthi1http://www.blogger.com/profile/02326883773117009327noreply@blogger.com