blank url wanted for downloads/ target="_blank" not working for only pdf files

I have clickable buttons on my website that take you to a new window to download files. As of now the file location/path is displayed in the url.
I want to have the downloads from my website open in a new window but not display the url – I want the url to be blank I found the following code to insert after the file location:

target=”_blank”

But it does not work for pdf file downloads it works for epub file downloads and zip-files but when I insert it after the pdf file code it does nothing.

Also the url does display in the new window for a second but after a second it disappears and becomes blank.

This code insert thing I mentioned above (and does not work -for some unknown reason – for the pdf file downloads) is just what I found on google.
I am not atached to using that code if something else is better – My idea is (and I have seen this in other websites) I want it so that the url never shows for downloads but it opens to a new window that is always blank for all (and only) the downloads on my website. That is the idea.

Also I already have a zillion downloads on my site and I do not want to manually go through a zillion times and put in that code for every download link.

Please help! Any tips would be great!

THANKS!

PS my website is Krishnapath.org