Entrained air removal from viscous paste in drum or pail

[ERT]

Hi,

I have an application where we pump a viscous adhesive paste from drums into other drums or pails. We then put the drums/pails under dispensing pumps at the robotic dispense line. It is essential that there be no air in the bulk material, because it causes problems for the adhesive application.

Can anyone suggest ways that we can remove entrained air from the paste while it is still in the drum/pail? The only thing we can think of is some sort or vibratory shaker. Is this common, or is there a better way to do this?

Regards,

ERT

 

[pipedream]

maybe you could pull a vaccum on the drum?
if the liquid is too thick for the air pockets to move to the top of the drum could you heat the paste with a belt type heater to make the paste less viscous?

hope this gives you some ideas.

G3

 

[MikeHalloran]

Could the robot's dispensing pump draw direct from the original shipping container? I.e., it's possible that your transfer operation is introducing the air.

To answer your actual question, one traditional way to remove entrained air is by pulling a partial vacuum on the container. For a very viscous fluid, you may have to hold the vacuum for hours.

You need to control the vacuum, too, e.g. with a vacuum regulator. It's not that difficult to crush a drum this way. According to a source I don't fully trust, the typical 55gal drum will collapse at about half an atmosphere. Try it on an empty drum. Step back; it will surprise you.

Crushing a drum full of adhesive will trash your vacuum pump and regulator and make an impressive mess; you'll want to set the vacuum regulator and lock it and use procedures and training so a collapse just won't happen.

Before proceeding, you need to check with the adhesive manufacturer for assurance that the vacuum won't cause changes in its properties.





Mike Halloran
Pembroke Pines, FL, USA

 

[scastillo]

I agree with MH, revisit your transfer ops as it sounds like this may be the root of your problem.

 

[DesignerMike]

They make specific drum unloading equipment for this exact purpose that work extremely well. It is by far easier to avoid getting air into the product from the begining than it is to remove it after you have introduced it.

The equipment is not cheap... but actually "priceless" when trying to solve this problem.

There are a couple of different manufacturers out there with different systems.

 

[ERT]

Thanks for all your input.

D-Mike, can you suggest a manufacturer? Two options would be great.

ERT

 

[scastillo]

ERT,

Check out Graco pumps:

http://www.graco.com/Internet/T_MainSite.nsf/Webpages/StartPage

I used to work for a company that did contract packaging on form/fill/seal machines, and on occasion we would run products such as ointments, heavy lotions, etc. We used their sanitary drum unloaders to transfer the product from the customer's 55-gallon drum to our own pressure vessels, and never had a problem with entrained air.

 

[DesignerMike]

Murzan also makes a good unit.