There are a few machines on the market that claim to "dry", and subsequently, "save" your wet cell phone and all of those contacts, photos, videos, selfies, diary, notes, memos, apps, music, and who knows what else that you forgot to back-up before your phone met Mr Toilet or Mrs Lake.
One of the most notable is TekDry's heated vacuum chamber. This post isn't to specifically pick on TekDry, or their innovative invention. This post is to pick on ALL "phone drying" gimmicky machines.
Any device "drying" machine is gimmicky and relies on dumb luck to "fix" a wet phone. The science (a heated vacuum chamber) is sound, but the logic is flawed.
2) Corrosion caused by the water or other liquid containing electrolytes. Most commonly, this is galvanic corrosion and can exist anywhere there are 2 or more metals of varying properties and electricity, though electricity isn't always needed.
3) Board-level problems, ie short circuits and open circuits. An open circuit is when something was short circuited, but became so hot that it failed and the burned out component no longer conducts electricity and the flow of electrons ceases. A short circuit is when electricity is following a pathway that it wasn't designed to follow - the electrons (electricity is the flow of electrons) are taking a short cut to their destination. Both short and open circuits can be difficult to test and locate. In addition, depending on the severity and depth of the problem, they can be expensive to repair, and even exceed the value of the device - at which point, data recovery should be the only reason to proceed.
The water is only one part and the simplest to resolve. TekDry's and similar machines only address the water portion of the equation and do nothing to remove the corrosion or diagnose and repair board-level problems.
Simply evacuating the water as a "solution" is no solution at all. You could do that for free by opening up the phone as much as possible and taking a blow dryer to it - though if you're not careful and get a little overzealous with the heat, you could actually melt plastic components or warp the phone's frame (such as the plastic found on most Android phones). On iPhones, there's plastic around the charge port and headphone jacks. I personally don't recommend baking the phone in an oven or using a blow dryer or heat gun to dry a phone. You're only addressing one part of a 3 part problem when you do that, and you risk damaging the device. Then again, it's already damaged by the water. If you don't care about the data, or the device, do what you want to it. ;)