You might help the wear situation by using a balanced slide valve. There is an article in Live Steam magazine showing how to use an "O" ring to balance the flat valve which is called a "D" valve over here in the colonies.. If anyone wants a photo of the arrqngement, I can email one. That is provided I can figure out how to do it with my new computer!!!!!!! Jesse at Troy, TN On Mon, Mar 19, 2012 at 4:15 PM, Barrie Purslow wrote: > Hi Peter, > > As far as I am aware the problem is due to the high contact pressures > found in slide valves and the higher temperature of superheated steam. > If you are using cast iron valves in a model there shouldn't be a > problem especially if your lubricator(s) are reliable. Some other > material combinations may cause problems especially if you have decent > i.e. radiant superheaters and poor lubricator(s). > > The answer is to make the slide valves out of carbon filled ptfe. > Gives an excellent seal, low friction and is immune to corrosion. > Excellent for regulator slide valves too. > > Barrie > > > ----- Original Message ----- From: <peter.chadwick@xxxxxxxxxxx> > To: <modeleng@xxxxxxxxxxxxx> > Sent: Monday, March 19, 2012 6:56 PM > Subject: [modeleng] Re: Naive question > > >> Barrie, >> Yes. Some books call them slide valves, some call them flat valves - >> which >> they aren't really, but it perhaps illustrates the concept.. >> >> Peter >> >> >> >> From: Barrie Purslow <bpduo@xxxxxxxxxxxxx> >> To: <modeleng@xxxxxxxxxxxxx> >> Date: 19/03/2012 16:52 >> Subject: [modeleng] Re: Naive question >> Sent by: <modeleng-bounce@xxxxxxxxxxxxx> >> >> >> >> Peter, >> >> Do you mean slide valves? >> >> Barrie >> >> -----Original Message----- From: peter.chadwick@xxxxxxxxxxx >> Sent: Monday, March 19, 2012 2:23 PM >> To: modeleng@xxxxxxxxxxxxx >> Subject: [modeleng] Naive question >> >> I keep reading in all the books that flat valves and superheated >> steam >> don't go too well together. >> Why? I can't see it being down to port area...... >> >> Peter Chadwick >> Swindon >> ---------- >> This email is confidential and may contain information that is >> privileged >> and >> exempt from disclosure by law. If you have received it in error, >> please >> contact >> the sender immediately by return email and then delete it from your >> system; >> you >> should not copy it or disclose its contents to anyone. Emails are >> not >> secure >> and cannot be guaranteed to be error free as they can be intercepted, >> amended, >> lost or destroyed, or contain viruses. Anyone who communicates with >> us by >> >> email >> is taken to accept these risks. >> >> >> MODEL ENGINEERING DISCUSSION LIST. >> >> To UNSUBSCRIBE from this list, send a blank email to, >> modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the >> subject >> line. >> >> MODEL ENGINEERING DISCUSSION LIST. >> >> To UNSUBSCRIBE from this list, send a blank email to, >> modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the >> subject >> line. >> >> >> >> >> MODEL ENGINEERING DISCUSSION LIST. >> >> To UNSUBSCRIBE from this list, send a blank email to, >> modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the >> subject line. >> > > MODEL ENGINEERING DISCUSSION LIST. > > To UNSUBSCRIBE from this list, send a blank email to, > modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the > subject line. MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.