METHOD TO REDUCE VIBRATION DURING WRINGING IN WASHING MACHINES OF DRUM TYPE Russian patent published in 2012 - IPC D06F37/20 

FIELD: textile, paper.

SUBSTANCE: drum speed-up in process of centrifugal wringing of linen during the first period of time τ₁ takes place with acceleration ε₁ to the value of angular rotation frequency Ω₁ equal to 2/3ω₁ and corresponding to the start of the resonant zone in the speed-up period, where ω₁ - internal frequency of oscillations of the machine washing unit during speed-up. As the drum angular rotation frequency reaches the value Ω₁ = 2/3ω₁, during the speed-up period τ₂ the speed-up acceleration ε₂>ε₁ increases significantly due to supply of additional capacity to the drum drive so that the time period τ₂ is characterised with quick passage through the resonant zone, equal to the range of the internal frequency 2/3ω₁…4/3ω₁. The intensive drum speed-up during the period τ₂ at the acceleration ε₂>ε₁ is continued to the value 4/3ω₁, which determines the end of the resonant zone and the start of the period τ₃ of the established drum rotation at ε₃=0 and Ω₂=const. Upon completion of the wringing process the drum is braked with acceleration 84 for the time period τ₄ to the rotation frequency value Ω₃ = 4/3ω₂ corresponding to the start of the resonant zone during braking, where ω₂ - internal frequency of oscillations of the machine washing unit at the end of wringing. As the drum angular rotation frequency reaches the value Ω₃ = 4/3ω₂, during the speed-up period τ₅ the intensive drum rotation braking is applied with considerable increase of braking acceleration ε₅>ε₄ so that the time period τ₅ is characterised with quick passage through the resonant zone, equal to the range of the internal frequency 4/3ω₂…2/3ω₂, and intensive braking of the drum during the period τ₅ at the acceleration ε₅>ε₄ is continued to the value 2/3Ω₂. Then lowering the drum rotation frequency during the period τ₆ is continued without additional intensive braking until full stop of the drum.

EFFECT: increased acceleration of drum speed-up due to supply of additional drive capacity when passing through the resonant zone, lower vibration, power consumption, noise level, higher reliability.