slurry pipe lines / pump systems 2

[mechanicaldup]

Hi

where can I get design guidelines on slurry pumping systems?
I want to know what to do to prevent settlement on pump shut down.

 

[sprintcar]

http://www.pumps.org

is Hydraulic Institute

or try pump manufacturers like

http://www.giwindustries.com

"If A equals success, then the formula is: A = X + Y + Z, X is work. Y is play. Z is keep your mouth shut."
-- by Albert Einstein

 

[dbaird]

Contact:

http://www.seepex.com/cps/rde/xchg/SID-50EDD152-7A0EC37D/en/hs.xsl/index.html

David Baird
mrbaird@hotmail.com
Sr Controls Designer
EET degree.
Journeyman Electrician.

 

[stanier]

Go to the GIW, Bechtel, BHRA websites and request their technical papers. Some are free. GIW also has software known as SLysel which they can provide to purchaseers of their pumps.

BHRA also have conference proceedings of their bi annual slurry transport conferences.

Some books worth investing in.

Slurry Transport Using Centrifugal Pumps- Wilson Adddie & Swift

Design of Slurry Transport Systems- BE Jacobs

Non Newtonian Flow in the Process Industries- Chabbra & Richardson

 

[mechanicaldup]

thks gents
what advice do you have to prevent settlement of slurry in the the line on pump shut down(stop of flow).

 

[OliverF]

It depends on the conditions of the slurry and the machines involved (pumps, dryers, filters, centrifuges etc.)
Generally slurry lines need to be routed with maximum slope so that they are self draining. No pockets, dead ends etc.
Flush connections with minimum distance have to be foreseen upstream and downstream of valves etc. in order to remove plugging.
Eccentric reducers should be installed FOB (Flat on Bottom) in the suction line of the pumps with slurry service.
Special Valves (Piston type RAM-Valves or tank bottom valves) should be installed at places were plugging is likely to happen (pump suction line) to ensure flushing and draining.
Best
Oliver

 

[stanier]

What type of slurry are you handling? If you want to prevent solids settling you will need to understand the hindered settling regime. The chgaractgerisisation of a slurry involves over ten separate parameters that may or may not impact on each other:-

Size consist of particles
Size distribution of particles
Density of each consist
Density of carrier fluid
Velocity in pipeline
Yield shear strength of slurry
temperature
pH
Shape of particles
% of fines that may form a carrier liquid
diameter of pipeline
length of pipeline
chemical reactions that may be taking place

If you dont want particles to settle you may have to form a gel using an additive that will keep the particles in suspension. This happens in food preparations. Yoghourt with strawberries for instance.

 

[bulkhandling]

OliverF has given some good points.
Based on your application and layout, we try to vertically layout the discharge pipe to reach the high point as soon as possible and then slope (say 2% to 5% as a guideline) toward discharge end so when you stop the pump, most of the slurry will flow to the discharge. Some solids will settle anyway but it does not matter in most cases.
At the suction line, we normally use an automatic knifegate valve that's interlocked with the pump. When pump's shut down, the KG valve is then closed and an automatic drain valve is opened to drain the slurry in the suction pipe, in the pump and part of the discharge pipe. The drain pipe shall be big enough to reduce the drain time. Some solids will still settle anyway. If that does not bother you, you even do not have to flush it all the time.

 

[mechanicaldup]

thks gents
I have learned a few new things regarding slurry systems
especialy Eccentric reducers FOB (Flat on Bottom) and automatic knifgate valves on the suction line.

what about automatic flushing at pump shutdown?

 

[mechanicaldup]

bulkhandling

is the drain valve located on the discharge side of the pump?

 

[sprintcar]

mechanicaldup
GIW offers a Slurry Transport Class once a year - it sounds like this would be in your best interest. Contact them for details or look on the

http://www.giwindustries.com

website. They use the book that stanier mentioned so you bring home a copy. The upcoming class will be the one to attend!

"If A equals success, then the formula is: A = X + Y + Z, X is work. Y is play. Z is keep your mouth shut."
-- by Albert Einstein

 

[bulkhandling]

The drain line with an auto valve is normally located on the suction line between the suction KG valve and the pump.

If the application is critical, e.g., the slurry can clog soon, or the solids are very heavy, large-sized and settle very quickly, very high percentage, or any settlement can cause trouble to the process, you can install a (or a few) auto flush valves to interlock with the the system. In many my applications, I only use quick connects from the hose stations to flush the slurry lines.