Apparatus and methods described include a pump, whichincludes a piston, a diaphragm coupled to the piston anddefining a wall of a fluid chamber, and a snail cam. Thesnail cam is configured to, by rotating, alternatingly (i)pump fluid from the fluid chamber, and (ii) draw fluid intothe fluid chamber, by driving the piston to move thediaphragm. Other embodiments are also described.
