rule for Alpha+front slash but not numeric ?

[eluser]notebook[/eluser]
I need to get an input from my form field like this
Oracle PL/SQL
i.e. ,
All Alpha
front slash /
and
not numeric

i tried this bit it also accepts numerics

Code:

$this->form_validation->set_rules('Name','Name','required|min_length[5]|max_length[100]');

and when i write |Alpha
it doesn't take front slash /

please help