It can usually take up to 3 weeks to receive an update to
refund approved and refund sent from the IRS on its website using the Where's
My Refund tool. There's no way of knowing exactly when the IRS will update. You
will need to keep checking the Where’s
My Federal Refund? tool for updates.
Updates are made daily, usually overnight.
https://ttlc.intuit.com/replies/3332479
However,
since your return was accepted 20 days ago, if there has been no update tomorrow, you can follow
the instructions in the following FAQ to contact the IRS for further
assistance.
https://ttlc.intuit.com/replies/3302084