Hi,
yes, there are a couple. One is called the liquidator. Another is caled the Chemigem. They do have to be cleaned and maintained periodically as calcium has a habit of scaling in the small tubes and orifices.
As well, many folks here have made their own dispensers using a stenner pump, and a few parts for considerably less money than a ready made one, and the home made ones generally seem to be more reliable.
Do a search on the forum (top right of the page), and you will get lots of hits on the subject.