Pumping of Chocolate
Pumping of Chocolate
(OP)
I am involved in a project that requires the pumping of chocolate. I am looking for information regarding the pressure drops in pipes as well as pressure drops in fittings, such as bends, valves. I would like to know if anybody has some tips regarding the reticulation of chocolate?
Thanks
Finite
Thanks
Finite





RE: Pumping of Chocolate
If you know the viscosity (which must vary a lot with temperature, and with each 'recipe') you can go to a Moody diagram and determine friction factor verses Froude number. Then apply standard hydraulics formulae. You may have to do some temperature/viscosity measurements. I don't have any experience along those lines, think I'l go grab a handfull of M&M's and cogitate.. and look up reticulate...
Cheers,
Carl
RE: Pumping of Chocolate
http://www.chipsbooks.com/rheolflu.htm
RE: Pumping of Chocolate
You can use an internal gear pump (viking) check out:
http://www.vikingpump.com/engineer/10steps.htm
for some useful engineering data.
From http://www.pumpschool.com/liquidlist/index.htm#C
I got the following:
CHOCOLATE
Other Names: Bitter chocolate, sweet chocolate, milk chocolate, chocolate liquor, chocolate coating.
Viscosity: Varies widely from 2,000 cPs. to several thousand cPs. depending on type and process; also varies over normal temperature range of 38ºC to 93ºC / 100°F to 200°F. Chocolate viscosity is often expressed in degrees MacMichael. This is a standard viscosity unit of measure in the chocolate industry.
Or you can look for a progressive cavity pumps, the so called moyno pumps, I have seen pumping of peanut butter with a pcp.
http://www.moyno.com/moyno/main.html
Regards
Steven van Els
SAvanEls@cq-link.sr
RE: Pumping of Chocolate
Let me know if you need more help
Lionel.Pullum@bigpond.com
RE: Pumping of Chocolate
Well, as some people has told in this forum there's a very explicit way to size a pump for any kind of fluid you are involved with. The case of pumping chocolate or cooca mass is not as particular as we can think. Chocolate is Bingham's type Fluid and below a shear stress it remains static. You've to give it a more powerful impulse to make it moving and can pump it. Data above in the others replys will help a lot. In adittion, when you calculate the size of a pump you need to know the inlet presssure of the fluid, the outlet pressure, the viscosity of the fluid, the debit (or flow rate) you need and the equivalent lenght of the line. This equivalent lenght is the sum of the real lenght of the piping line and de fittings. Each fitting has an equivalent lenght E.g. 90° elbow = 9 ft. How ever, you must look such equivalent into a Chemical Engineering Book or Manual as "Chemical Engineering Hand book". For some information of pumping curve you can visit "www.gowcb.com", they have a catalog of very good pumps.
That's all.
Best Regards.
Chris
RE: Pumping of Chocolate
One other point, chocolate is "tempered" by work. I'm not sure i recall the types of pumps used (it wasn't my field) but with fluids that are sensitive to work a low shear pump might be required e.g. a piston type. My info on this is sketchy so I'd ask around on this or wait for some more informed replies.
JMW
www.viscoanalyser.com
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RE: Pumping of Chocolate
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-66322003000400012&lng=en&nrm=iso
My own experience of designing for fittings in laminar flow is that using K values from Crane 410 just does not work. It is worth putting in the extra effort and using the 3-K (Darby) or 2-K (Hooper) methods. Using published equivalent length numbers is surprisingly more accurate than fixed K values.
As to the pump - speak to the suppliers and find one who can show you a case history of using his pump for chocolate. Do not try to re-invent the wheel here, there could be big problems.
regards
Katmar
RE: Pumping of Chocolate
Measurements are made in Cuoette-type viscometers. These are viscometers in which the liquid whose viscosity is to be measured fills the space between to vertical coaxial cylinders, the inner one suspended by a torsion wire; the outer cylinder is rotated at a constant rate, and the resulting torque on the inner cylinder (or bob) is measured by the twist of the wire.
RE: Pumping of Chocolate
In the Searle type the inner bob rotates. In either type, the fixed element or the driven element can be on the torsion mounting according to manufacturer.
Some chocolate manufacturers produce their own viscometers, some with no outer sleeve.
Others are now using the new technologies such as the vibrating element sensors.
In many industries special units are used simply because of the technologies available. Today it is increasingly possible to correlate the measurement back to recognised units. As a consequence many older units of measurement are falling into disuse. Some persist even though now officially obsolete. e.g. Saybolt, Engler, Redwood.
The University of Ghent is conducting extensive research on chocolate technology. A search on their web site or an approach to the University may provide key data and recomendations.
JMW
www.viscoanalyser.com
Eng-Tips: Pro bono publico, by engineers, for engineers.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Pumping of Chocolate
The fluid is shear rate sensitive and the properties vary from increasing shear and decreasing shear. ie it is a dilitant fluid. Its propoerties vary in the time shear is applied and is thus described as thixotropic. These terms dilitant,thixotyropic, Bingham plastic and pseudo visco elastic are merely tags given by researches to describe the relationship between the material properties exhibited during a shear rate versus shear stress viscometry trial. Dont get too carried away with them. You have to do the lab work before you can give the properties a tag!
One sophisticated piece of equipment used for viscosity trials is the Weissenberg Rhegionometer. This can apply a shear stress at rates that are very low ie .00001s^-1. By measuring the shear stress at various shear rates one can cross plot each result to get the physical properties. At very low shear rates you can measure the yield stress effectively. Work by David Boger at Melbourne University is worth researching. ( He was awarded membership of the Academy of Sciences for his work in rheology)
As for pumping the stuff I used Mono progressive cavcity pumps. They do make a hygeinic unit. Pick a lrger slow running pump rather than the cheapest available. Keep the shear low. Make sure the piping is either heat traced or jacketted with hot water. By keeping the pipe wall surface at a temperature that will enable the fluid to flow you will avoid start up problems. The flow will effectively be plug flow. You may need an in line powered mixer to allow feed into other process equipment.
Avoid fast running gear or lobe pumps. Progressive lobe pumps run at low speed may be suitable but these have evolved since I left the food industry. Make sure the pump is jacketted or heat traced.
I have used these techniques to extrude chocolate onto biscuit bases, into ice cream etc.
http://www.egr.msu.edu/~steffe/freebook/STEFFE.pdf
RE: Pumping of Chocolate
RE: Pumping of Chocolate
http://www.discflo.com/index.html
RE: Pumping of Chocolate
Once chocoltae solidifies however, I believe it becomes fit only for farm fodder.
drapes
RE: Pumping of Chocolate
RE: Pumping of Chocolate
RE: Pumping of Chocolate
For the benefit of the doubt, maybe you could share to us the solution you have undertaken to this controversial, mouth watering subject matter "pumping of chocolate".
Cheers!