Expression: Format seconds to "dd HH:mm:ss"

Hi,

I'm having a problem creating an expression to calculate the time between two dates from different fields.

With ${entity.datetime2 - entity.datetime1} I get the results in seconds (I think).

Example:

Avbrott start - Start date/time

Avbortt *** - End date/time

Ordinare åter - Another end date/time

Avbrottstid - It's the result of "Avbrott start" and "Avbortt ***"

Stärningstid - It's the result of "Avbrott start" and "Ordinare åter"

Thank you!