Filling converted 12gal kegs from the bottom ?

[kabbo]

Hello,

I'm setting up a 12 gal setup with converted Sankey kegs as kettle, mash tun and fermenter.

I'll be welding some fittings on, such as a ball valve at the bottom side on each keg.
I'll be using a 1/25hp pump for the transfer (March MDXT-3).

My question is :
can I fill the kegs using this bottom ball valve, or gravity will force against the pump and ruin it ?

I would like to do this in order to have a completely closed environnement and to avoid contamination and splashing of the beer if filled by a top side ball balve...

Anyone have tried it ?

Thanks in advance.