Valve for high pressure , high viscosity, highly abrasive enviroment
Valve for high pressure , high viscosity, highly abrasive enviroment
(OP)
Looking for suggests for an application i am working on. Our process involves using a high viscosity, highly abrasive material in which we control the flow using a pneumatic actuated metal seated ball valve. Initially we had issues with the valves failing to open (prior to switching to the metal seated valve). We operate at a pressure around 1500 psi and the valve cycles about once per minute. The issue that we are having now are leaks occuring at the stem. This occurs over a short period < 2mos. Are there any suggests on what i can try, valves, different packing, etc.?





RE: Valve for high pressure , high viscosity, highly abrasive enviroment
You didn't say how hot the application is. If it's not too hot, and o-ring-sealed bushing below the packing helps to keep the grit out of the packing.
Thw pneumatic actuator is good because it probably does not put a side-load on the valve stem. Rack and pinion wont side-load the stem, nor will a scotch yoke. Make sure your mounting bracket and coupling are concentric anyway.
Live-loaded packing will help since it has a spring to keep compression on the packing as it wears. THe packing stackup should have a junk ring as the first element next to the process:usually this is a braided ring that can absorb grit instead of trying to seal around it.
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
The material does not come in contact with moving parts, and therefore does not foul up the components. The design uses a diaphram, made of polymer, that covers the orifice. The only contacting part is the diaphram on the orifice opening.
As you can imagine, diamond slurry is abrasive; we never had one clog or leak.
Charlie
www.facsco.com
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
Basically a large rubber tube inside a housing. When air is applied between the tubing and the housing, it compresses the rubber tube and stops the flow.
I used them for waste drains for the abrasive slurries. They are found in the agriculture industry
Charlie
www.facsco.com
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
The symptom that indicates side loaiding is that you tighten the packing until it seals, then, a shorwhile later, the packing leaks again. Tighten the packing until is stops and roughly the same period, it leaks again. On and on it goes until there is no adjustment left. Also, look at the type of packing used. For high cycle ambient temperature, would recommend filled PTFE v-ring (chevron) type. It is common for small ball valves to simply use plastic washers, which are OK for occasional manual operation, but won't last as long when automated with side loading.
bcd
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
The "seats" of a slab gate is perpendicular to the direction of flow, so it doesn't take as much abuse as the gate slide at 90 degress to flow when moving. Also, with a slab gate, there is no tradition gate valve's "seat" in which stuff can accumulate, allowing you to close the valve multiple cycles.
Also, what is "high viscosity"? And, what is "highly abraisive"? That may also help others give you a better suggestion.
"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
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RE: Valve for high pressure , high viscosity, highly abrasive enviroment
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
We're still in the process of trying different packing to address the leakage of stems. Currently looking at UHMWPE material.
I've looked at other valve types but havent found a slab gate valve for the high pressures and room to fit in our application. I don't have the exact measurement for viscosity but it has the consistancy of a thick cement paste and is ceramic based.
The valve body is coated with Armaloy and the ball is stellite
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
The Serck Audco super H pressure balanced plug valve is worth considering for your abrasive service HP application the body internals can be hard faced for extra errosion protection.
follow the link below
http://www
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
UHMWPE can be used as a packing material, however, it is very limited on temperature. I would not recommend it if you see temperatures above 175F. My feeling is that you are more likely to be side loading the packing with misalignment of the valve and actuator, than having inferior packing materials. (look at BCD's comments) However, if you still feel that it is the packing, Chesterton offers a guarantee on their packing for 1,000,000 cycles. You can reach them at (800) 263-9140. They will tell you that it is extremely important not to overtighten the packing. For packing to work, you need to have a bit of movement or it won't seal properly.
Also take a look at www.mclassvalves.com. Gosco manufactures a valve that will work in this application.
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
Geoffrey D Stone FIMechE C.Eng;FIEAust CP Eng
www.waterhammer.bigblog.com.au
RE: Valve for high pressure , high viscosity, highly abrasive enviroment
RE: Valve for high pressure , high viscosity, highly abrasive enviroment