I don't have any pics of mine, which is not in use right now. I made it out of a hot water heater element (220v element that I ran at 110v, resulting in 1/4 the rated output), a long pipe nipple, and a couple of pipe tees. I think my entire cost at the local big box store was probably less than $20.
However you plumb it in, make sure the element is always covered in oil to reduce the risk of fire.
To be honest, I don't recall. I probably built it eight years ago. It's just a standard 220v hot water heater element, and cost $10-12 at the Lowes store. If I had to guess it's in the 4500-watt range? But again, I wired mine to run on a 110v socket, which gives you 1/4 the output -- so I'm probably around 1100 watts when it's running. As I said, I used some pipe tees, caps, and reducers to connect it to the rest of my centrifuge plumbing. It's at the lowest point (basically ground level) of the system so that it does not trap an air pocket. At best, air can quickly kill an element, or at worst be a real fire hazard.
My design is not especially fancy, and it does NOT include any thermostat or automatic temp control, does not have a flow switch, or any of that. I realize this is not ideal. My personal policy is never to run a heater element unless I am on-site to monitor and manage the process. When I centrifuge raw oil, I'm present while the heater is on. Once I am happy with the temperature of the oil (usually running ~50 gallon batches), I turn off the heater element and continue to run the centrifuge for an hour or two, depending on how dirty the oil is.
Same thing for my biodiesel production in an appleseed-style processor. I always bring the oil up to temperature by heating and circulating the oil in the processor (while monitoring), then I turn off the heater elements and add the methoxide. Only then do I feel comfortable stepping back and letting everything run its course. Even then I am rarely far from the scene -- might be in another part of the shop or out in the lawn, etc.
I use a DYI SimpleCentrifuge open bowl. I don't heat the settled RAW any more as I interested in getting the FAT out of the VO (longer VO filter life). As far as temp control, used the hot water tank temp control unit. It can be set at different temps. It's not very accurate, but close enough. Box stores have them. I also wired in a light bulb socket and blue light bulb that turns on when the heating element(s) are energized and shuts off when the elements are not energized. Make sure the heating element is completely submerged in oil - the fire element is very real if not observed! Might suggest getting a K Class 6 liter Fire Extinguisher ($135) close to where WVO is cleaned. Send a PM and I'll post a few pics of the heater/blue light.