A calf slicer is a compression lock that crushes the calf muscle, and I've heard the terms "calf crush", "calf slicer", and "calf crank" all used interchangeably. At 2:00 of this video, Eddie Bravo describes the Vaporizer as a "toe hold slash calf crank, slash devastation...this one is very hard to resist." (Emphasis mine.)
So there's an element of calf slicer in the Vaporizer, but it's also got elements of a toe hold, which is a separate knee-torquing attack. There is overlap between a plain calf slicer and the Vaporizer but they're not the same.
In a calf crank the movement is in line with the foot-ankle-shin structure, while in the vaporizer it's not: this creates torque on the hip/knee/ankle joints, which is a movement pattern not found in a calf crank.
This twisting motion is found instead in many other submissions such as the toe hold, heel hook, kimura and omoplata. You might think of the vaporizer as an omoplata on his leg combined with a calf crank.
In other words, if in the calf slicer you are using his lower leg as a prybar and your shin as a wedge, in the vaporizer you are also using his leg like a wrench.