What is the difference between flow tee and bar tee in piping design?

Bar Tee has got the branch opening closed with flat Bars so as not to allow the PIG to pass through the branch pipe portion than to the mainline.

In case of Flow Tee the purpose is the same (i.e. not to allow PIG passage), here the flowing liquid get accumulated in the circumference of the annular space and while pig moves thru' flow tee, maximum fluid is passed on to the branch piping.