How to ignore double or multiple spaces when finding duplicate data

I am trying to find duplicate data, including data with double or multiple spaces between the words that makes up the names. This is in SQL Server

Example:

Product Names in a Product Table:

Lime Cola

Lime Cola

Lime    Cola

This query will return just the first two, but not the third one:

SELECT * FROM [DBNmae].[dbo].[TableName] WHERE [productname] IN (SELECT [productname] FROM [DBName].[dbo].[TableName] GROUP BY [productname] HAVING COUNT(*) > 1)

How can I adjust the query to return all three?

That means, the double or multiple spaces within  "Lime    Cola" should be ignored.

Thanks,

Cypray