The ornamental design for a waterpurifier, as shown and described.
1. Water purifier
1.1 : Perspective
1.2 : Front
1.3 : Back
1.4 : Left
1.5 : Right
1.6 : Top
1.7 : Bottom
1.8 : Perspective view 2
1.9 : Front view 2
1.10 : Back view 2
1.11 : Left view 2
1.12 : Right view 2
1.13 : Top view 2
1.14 : Bottom view 2
1.15 : Perspective view 3
1.16 : Front view 3
1.17 : Back view 3
1.18 : Left view 3
1.19 : Right view 3
1.20 : Top view 3
1.21 : Bottom view 3
The broken lines depict portions of the water purifier that form no part of the claimed design; reproduction 1.1 is a front perspective view of the water purifier; reproduction 1.8 is a front perspective view in a condition that the outlet has been rotated to the right; reproduction 1.15 is a front perspective view in a condition that the outlet has been rotated to the right and then extended downwards; reproductions 1.2 to 1.7, 1.9 to 1.14 and 1.16 to 1.21 are the front, back, left, right, top and bottom views of reproduction 1.1, 1.8 and 1.15, respectively; this design is for a water purifier which can be installed regardless of the place due to the outlet which can be rotated as shown in reproduction 1.8; the outlet is also extendable downward as shown in reproduction 1.15, which allows to pour the water into containers of various sizes.