I currently have three of those. I employ the wire cage method to break them. The objective is to cool down their body temperature which helps lower the hormones. However, it varies as to how long it will take.
My previous broody, a week ago, took two weeks in the broody cage before she was discouraged from fleeing back to the nest as soon as she was released. These current ones are more typical. Two were discouraged in two days, and the third required three days, just being released this morning. I haven't checked on her yet to see if she's back on the nest, though. If she is, then back into the cage she will go.
As an additional aid, I place an electric fan to blow on the underside of the cage. This keeps air circulating which is in opposition to the warm, steamy confines of a nest, which is ideal for a broody. If it's very warm where you are, you can bathe the under parts of your hen, and the fan blowing on her will then have maximum effect.
Make sure the cage is elevated or the air won't be able to circulate properly. You will need to plan on keeping her in the cage at night, too, until these urges pass. I wish you luck!