Lobe Pump

[davedaneshi]

I want to use Lobe pump for transfer of personal care products from storage tank to filler. The pump design data would be 20 to 25 GPM at 120 to 150 psi.We are concerned about product aeration and bleeding air when we get air pockets. How lobe pump tolerate dry operation and how it affects products shear during operation.
Please let me know if you need more information or data.
Thanks,
Dave,

 

[georgeverghese]

Its a bad idea to operate a lobe pump with air entrained in the feed stream - the entire suction line to the pump must also be fully liquid primed.

If air gets trapped at the high point in the casing of the pump, you could develop hot spots o nthe dry parts.

 

[Latexman]

If the lobe pump is "externally gear driven", like a Waukesha, it will tolerate dry operation. This comes at a price though, it has two seals, one for each shaft.

An externally gear driven lobe pump has no points of contact in the pumping chamber, but there are some tight clearances. In those tight areas, there will be high shear, but the average shear of the pump is quite low. If it is a concern, have the pump vendor(s) test your product.

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

 

[davedaneshi]

Thanks for responses.
Pump suction side will be directly connected to storage tank with full flow, however, at the end of each batch air will pass through the pump.
Reg shear rate, we did viscosity vs shear rate test on number of fluids yesterday. Viscosity goes down as we increase shear rate. It goes back to start point as the shear is removed.
I think lobe pump is a good choice and 400 to 500 rpm would be the pump speed.

 

[Compositepro]

You might want to consider an Air-Operated Double-Diaphragm (AODD) pump. They are low-shear, self-priming, pressure-limiting, have no seals, and less expensive to buy and install.