Liquid slurry piping systems transport solid particles entrained in a liquid carrier.
Water is typically used as a liquid carrier, and solid particles are commonly granular
materials such as sand, fly-ash or coal. Key design considerations involve the nature
of the solid material, it’s particle size and the carrier liquid.

CODE-Slurry Transportation Piping Systems B31.11 - 2002

Piping design for slurry system is different in two important aspects
1-Material of construction of pipes carrying it.
2-Line routing

Let us discuss line routing aspect the liquid slurry service piping system.
Though the particle size is also one of the important point governing below points...let
As far as I know...

- We should avoid fittings / valves or anything in the piping system which can cause contamination of slurry particles in them. Example- SW Fittings,

- 5 D Bends to minimize wear at the turns if used LR elbows.

- No POCKETS in the line.

Any additions to these will be very helpful for all the pipers on pipingdesignes.com

Depending on the slurry but we had to put plenty of drains in, generally put them in larger than you would for liquid service.
You do this because if the pump fails or something else halts the flow in the line, you need to be able to fully drain all the line rapidly before the solids settle out and block the line. Aslo plenty of flanges for 2 reasons if the latter happens and to aid in replacement of worn sections.I should add I wouldnt worry about socket welds, the materials you mentioned cross contamination wouldnt be an issue. unlikely that you will have fittings 2" down on slurry lines anyway.

The last time I did "Slurry" piping we used "Pinch Valves" (http://www.redvalve.com/rv/index.php/co ... ew/67/116/) for shut-off and control. The great thing about this type of valve is there are no pockets to collect or trap the fines in the slurry.

I'm currently working on a mining job with plently of Slurry and tailings lines.

@WNRF,

Good call on plenty of flanges, or better still, Victaulic type connections.

Not just for replacement of worn out sections, but also to disconnect and rod-out quickly, also you also want to allow regular maintanance, including rotating the the pipes to prolong operating life .... Vic type fittings are great for this, and high pressure applications aren't "usually" a concern in slurry applications.

@JOP,
Agreed.
The pinch valves are pretty much essential for this applicaion.

I did a "klinker" system on some coal pulverizing equipment, where we were flushing the "other then coal" (klinkers) out of a hopper. We used cast iron piping with 5D wear-back elbows and dresser couplings to connect the fittings. Interestly we also used a mechanical brace at the elbows, because if there was a plug in the line the operator would bump up the pressure in the line to try to clear it out, but could just as easily blown out the fitting. I believe we used knife gate valves ...but that's been afew moons ago!

Do these valves leak (at full closure)?
I am asking this because it will be pressing the soft tube using the sliding metal bars as clamp.

Also, if the slurry contains solids which are abrasive then can they still be used?

Do these valves leak (at full closure)?--No

I am asking this because it will be pressing the soft tube using the sliding metal bars as clamp.-- Correct

Also, if the slurry contains solids which are abrasive then can they still be used?--Yes

shrivallabha, as with any other valve you use on a project you need to contact the manufacturer and get the complete technical specifications including alternate materials of construction and limitations for pressure, temperature, corrosion and erosion. It is also wise to supply the valve manufacturer with your specific application and ask for their comments, opinion or advice.

I have used both Pinch valves and kife gate valves in slurry service. The knife gates tend to work better with large pneumatic actuators for piping where rock or stone is involved. I have seen demos of knife gates close on a 4" rock and seat properly.
Lap joint flanges can be used to rotate the pipe 1/4 turns for even wear and i have used chrome carbide lining in the pipe for extra durability.
Even with that the pipe still wears out and has to be replaced which is removed per flanged spool.
In Oil Sands mines the bitumen is so thick and viscous that check valves are not required on the centrifigal pumps discharge piping as the back flow is so slow that the velocity doesn't reach enough speed to damage the pump.

I would like to add another items:
- We are using Knife Gate Valves.
- We consider to install flanges at elbows that can be useful for the operators to solve any blockage on pipes.
- Erosion and abrasion effects must carefully consider on pipe thickness.
- The vlaves must be minimized, the valves are possible Slurry settling points.

Regards