The US patent office doesn't check for accuracy or verify tests performed. The patent office is more concerned in prior art (previous similar patents), that all forms and paperwork have been properly submitted and especially that all Patent fees have been collected before prosecuting and granting a patent.
The patent you reference is a utility patent, a new way of making Colloidal Silver , rather than a new form of Colloidal Silver . Interestingly enough, the patent added (updated to include) bubble stirring in 2006. At that time there had been available for sale over interstate trade two generators with bubble stirring for at least 4 years.
The ABL product does work and the company has performed many tests (almost of these tests offshore in India). But the patent is brings value to ABL's parent company (to whom the patent is assigned) a silver mine.
PS As my specialty is electronics, you might be interested to know that the US Patent office granted more than 12 patents to one company for previously patented circuit designs that became public domain between 1952-1955. The US Patent office doesn't check patents unless every "t" is not crossed nor lower every case "j" or "i" dotted.