presently using 3 9volt batt. to produce 27 volts to generate current to 2 silver rods going into herbal formula long term not cost effective, Please-need to make a converter from my wall socket 1110/120 volt AC to 27-36volt DC connected to the silver rods going into liquid formular,help? thanks O'Malley

 

Be carefull with mains if you've not designed before, but all you need (Assuming your formula is watery type liquid) is a mains transformer to something like 18 to 25V AC and a bridge rectifier and capacitor. Standard unrgulated PSU, the DC you get out will be higher than the AC stated if you have low a low current flowing. Need to know current flowing in order to calculate the size of transformer but sounds like it may be smallish.
A fuse on the input will be a good idea! Or a current limiting resistor if there is a chance you may short the rods together.

 

You likely just need a transformer of the desired voltage and current rating, and a bridge rectifier. Since it's going to silver rods, it likely won't mind pulsating DC, so you wouldn't need a capacitor filter.

 

You could also just buy a prebuilt supply like this 30VDC @400mA ($20) http://www.mpja.com/30VDC-400mA-Unregulated-Desktop-Supply-HP/productinfo/15890+PD/

or this if 24V would work.. http://www.mpja.com/24VAC-40VA-Plug-Transformer/productinfo/12637+PA/

or others they have (open frame type,etc..)