Butterfly valve disc material for slurry service

[cokeguy]

We are using butterfly valves to throttle limestone and calcium sulphate slurry flow in 4" and 6" pipes, not the ideal application for this type of valves I realize, but hey, we simply spend a couple hundred dollars every few months to change the discs and it has worked out OK for us. We are considering changing to, for example, pinch valves, but because of cost and the required piping changes we have not made the move yet. The original butterfly valves had CPVC or PVC discs, so all replacement discs I have ordered have also been PVC or CPVC. However, I've been told that if I switch to polypropilene discs we should get significantly more wear resistance, is that correct? Any suggestion for other disc materials, preferably as cost effective as CPVC or PPL for this type of applications?

 

[JimCasey]

Cast Iron is pretty abrasion resistent. That's why the brakes on your car are CI. Other choices: Rubber coated, or if you can find it, Ultra-High Molecular weight Polyethylene (UHMWPE) is a very abrasion-resistant polymer.

 

[bmsg]

I think cast iron valves will be excellent:the valve supplier will suggest you more materials.

a suggestion: try using a ball valve: a 'V' notch ball valve will give you good control.

 

[JimCasey]

V-Ball valves are great for paper stock. The ball is usually Cr-Plated 317 SS.

On slurry, Once the stuff chews thru the Cr, the 317 is pretty soft. Especially if the ball valve is controlling at small flows-then the V-Ball becomes a keyhole-ball when the v-notch wears thru at the point of the V.

AND, a ball valve costs many times more than an equivalent-size butterfly valve.

 

[sairaj]

we have seen rock phosphate and gypsum handling slurry services they use HDPE (High density poly ethylene ) Polypropyline will also a right choice.Check about this two

 

[Ashereng]

There was another thread on errosive service using a pinch valve. You may want to try to look that up.

The gist of that thread was a "soft" pinch valve (some type of polymer, rubber, etc) was better at preventing erosion and abrasion than metal.

 

[TangoCleveland]

Take a look at PosiFlate butterfly valves. They have an inflatable seat (rubber body liner), wide variety of disc materials.

Larry