I have seen several projects for keg washers that involve large pumps, buckets, pvc pipes, fancy spray heads, etc. However, I believe that the simplest path is often the best and least expensive. I came up with this design after a having a conversation with a unicorn. (Just wanted to see if you're paying attention.) I decided to utilize the keg itself to move the cleaning solution (PBW) around the keg. So here is the project.
1) 12 volt self-priming water pump with 3/8" barbed inlet and outlet.
1) 3/4" x 16" x 5.5" plywood
1) 3/8" wood dowel
1) 3/4" wood dowel
1) 2' length of 3/8" id high pressure pvc tubing*
1) 2' length 1/4" vinyl tubing*
1) <1' 1/8" vinyl tubing*
1) 3/8" "T" barb
1) 1/4" "L" barb
1) 360 degree micro-sprinkler (1/8" input is typical)
1 each) gas and liquid side keg connectors
4) 1" wood screws
4) 1/4"-3/4" adjustable hose clamps
*The outside and inside diameters of the tubing fit together without needing reducers.
1. The pic on the left show the base platform of the keg cleaner. This is simply the support for the pump. The cutouts allow access the keg's valves and the center hole is for the micro sprayer. (I started to cut a larger hole as seen, but decided it was unnecessary.) The plywood is 16" x 5.5" x 3/4"and the hole is 3/8" to accomodate a 1/4" id tube. The cut outs are 2" deep and 3" wide.
2. The next step is to drill 2) 3/4" holes 1/2" deep on the underside of the base. Note I marked the position of the keg on the wood to keep the holes outside the rim of the keg.
3. Cut 2) 3/4" dowels approx. 2 1/4", place the dowels in the predrilled holes and mark them at 1.5" from the base. Drill a 3/8" hole part way through the dowel. You may want to angle the drill slightly away from the base so the pegs will slide into the keg's handles more easily.
4. Cut 2) 3/8" dowel approx 1.25" long. Insert them into the predrilled holes and place the contraption on a keg. You will want to turn the 3/8" dowels outward until it will fit under the keg handles. Once you feel good about their position, they can be glued into place. I added another 3/8" dowel to keep the base secured to the keg. Just make a mark about 9" from both 3/4" posts in the center or better yet, mark the position against your keg.
Paint the whole thing to whatever color you desire to protect it from water damage.
5. Here is the completed, crazy contraption. The pump's (SeaFlo) specs are: 12 volt, self priming, works with medium hot water (140F), 1.2 gallons per minute - which is plenty, 2.7 amp max. A 3 amp 12 volt power supply provides the power. A 360 degree micro sprinkler sprays the inside and the pump pulls the warm PBW from the liquid side of the keg to the sprinkler and gas side. I added (not pictured) a 1/4" valve to the gas side tube to force more water to the sprinkler. I do not believe the high pressure hose is needed but that's what the pump recommends. (Don't forget to thank the unicorn - again, just checking.)
(Micro sprinkler in the keg.)