Is it ever right to do this?

This is a general question on a typical situation:
you have AK in LP and there were 3-4 limpers before you.You raise PF and then flop top pair (ex. A-7-2r).
One of the limpers bets into you.

This usually means they have an Ace and wants to see if you have AK or AQ. They know that if you have AK, you will raise and if you have KK or QQ, you will call or fold. I ALWAYS raise in this situation and if the original better calls only, then I know he likely has Ace-weak kicker....and if he 3 bets, he's got 2 pair or trips. SO my question is this: should I just callthe bet so he thinks I don't have AK and if he bets the turn when a brick hits, I give him a 20 shot(playing 5-10)? or should I remain predictable and just raise him on the flop.

I always raise because I want the money in there because I think I'm a favorite and to drive out the gutshots.......but I'm thinking maybe this is not always the best play.