Is this an ok washing machine back up plumbing fix?

[practicaldiyer]

Hi, there is slow drainage in my block which I can't control. I want to separate the washing machine outlet from my sink ubend to limit flow up into my sink. And eliminate the vacuum which can suck waste back into the machine when flow is slow.
Picture shows my intended plan. Any flaws?
Grateful for comments, criticisms.
Thank you!

 

[practicaldiyer]

Oops sorry

 

[Madrab]

That's the better appliance standpipe approach, the only issue is though that if the washing machine pumps faster than the main waste run can drain it with the stand pipe being capped then the outflow from the washing machine will probably still end up backing up into the sink.

 

[practicaldiyer]

Oops sorry

 

[practicaldiyer]

Thanks Madrab. Yes agree, the water has to go somewhere. Plumbers have often said if the waste hose is high the water won't go back into the machine, but it did! I wonder if you know how/ why the air release valve could solve this?
Thanks again...