I know to make a cloth pure from urine we must wash it thrice. I want to know that I wash my najis clothes once by hands and then in washing machine with other clothes (wachine machine is connected with water) we repeat the cycle 3-5 times. The cycle contains adding water to machine, spinning it then draining the water and then drying them in the dryer of the machine. Does that process make the najis clothes tahir as well as the clothes?

Yes many scholars have stated that washing machines do purify clothes. So you may consider the clothes pure. And to purify urine washing twice is sufficient and thrice is not mandatory.