Insert Space Between Words

I'd like to learn how to separate two values with a space, for example I'd like to insert a space between Vol.6 so it'll be Vol. 6

Thanks a lot.

There's lots of good information in the FAQ section:

/t/967/1

Checked this thread. No useful info for me there.

Think of replacing the one dot character with a string of two characters (dot and space).

DD.20121212.1935.CET

Thanks, but not a good idea since the dot is often used for the (year.month.date) value.

So what?
Do you want to put a space or not?

Your example relates to the album-tag. Normally there is not date in the album tag.
If you only want to put a space in "Vol.x" you have to replace "Vol." with "Vol. ".

Normally yes, but often there is.

Tried, it did it, but also all "Vol. 6" values became "Vol. 6".

I'm looking for a way to specify a space after the dot for a concrete word (vol. in my case) only if there is no already a space after the dot.

You can set the Filter to ...

TITLE HAS "Vol." AND NOT TITLE HAS "Vol. "

... then apply ...
Converter: Tag - Tag
Field: TITLE
Format string: $replace(%TITLE%,'Vol.','Vol. ')

This works without Filter, but setting Filter is recommended ...
Converter: Tag - Tag
Field: TITLE
Format string: $regexp(%TITLE%,'(Vol.)(\S)','$1 $2')
... or ...
Format string: $regexp(%TITLE%,'(Vol.)(\d+)','$1 $2')

DD.20121213.1727.CET