How to make a pipe following helical path upward parabolically inward?

i am making cooling pipe arrangement for a furnace.this cooling pipe is for torispherical dish. here the pipe of some half inch dia moving helically upward and parabolically (or the curve for torisphericall dish,which apprx looks like a parabola) inward? It will be greately helpful for my project.

Thanks,

LinGesh G

lingesh@conceptia.in

SolidworksParts And Features