Will this trap prevent back-filling?

[WaterTight]

I know that's not one of it's advertised uses but it's also a one way valve yes?

https://www.NoLinkingToThis/p/osma-...mm/3962k#product_additional_details_container

 

[WC1]

Not sure what you're trying to fix but yes, its a 1 way valve.
This is also a 1 way valve

https://www.NoLinkingToThis/p/mcalpine-t28m-nrv-non-return-valve-white-40mm/61561

 

[WaterTight]

I'm trying to plumb in a washing machine where there is no room for a normal standpipe and it's going to join onto an existing waste run under a kitchen sink after the sink trap (thereby not benefitting from the sink trap's preventing smells getting back into washing machine and at risk from back flow when sink is emptied )

So essentially I need something in-line that will act as a trap to prevent smells, but also prevent backflow when sink is emptied. I guess I needn't worry about syphonage if using waterless trap/similar as there is nothing to syphon. I also believe they (or at least the mcalpine version will open and allow air to be drawn into the waste pipe, effectively being vented too...?)

Do you think this would do the job?

TeeVent | McAlpine Plumbing

Upgrade your plumbing system with the Teevent, ensuring efficient air ventilation and water flow.

mcalpineplumbing.com

Just connected onto a new bit of waste pipe which then joins the sink waste after the sink trap?

It should provide ventilation and prevent back-filling but not sure if I also should fit one of these as well to prevent the smells :

Self-Closing Waste Valve - Loose Nut x Compression | McAlpine Plumbing

Upgrade your waste management with the Self Closing Waste Valve, featuring a Loose Nut x Compression for efficient water flow control.

mcalpineplumbing.com

...or whether the first one will do all 3 in one (non return effectively acting as trap to prevent smells and back-feeding, vented, waterless and opens to allow air through so no need to worry about syphonage or venting issues....?)

 

[Ben-gee]

You mention kitchen sink, the usual way out of this is to connect the washing machine waste to a spigot on a trap under the sink- they are specifically designed for this.

If it won’t reach, join an extra drain hose to the existing one.

 

[WC1]

types like you have there don't like the fluff from a washing machine, have you considered a running trap?
A hockey stick or putting it into the sink waste are really the best way imo.

 

[WaterTight]

I put a running trap on it and even replace one of it's elbows with an elbow of an anti-syphon p trap but it meant that every time the sink is emptied the anti-syphon trap vibrates, I guess as the air admittance bit jumps up and down. Plus there is nothing in the running trap to prevent back-filling.

I get that the waterless types may not like fluff from the machine but putting that aside for a mo, would one or both of the above tick all the boxes of preventing smells, preventing backflow and avoiding the vibration of an anti syphon trap going off every time the sink is used?

Unless anti syphon traps don't normally make noise or maybe it was because I adapted a running trap to include one? I see McAlpine do a "silent anti syphon trap" which I guess should be quiet. But wouldnt prevent possible backflow...

 

[Ric2013]

HepVo valves can slurp in use, so aren't entirely silent, but I wouldn't want to talk you out of using one, and they will protect from backflow.

If suction is significant, you could potentially siphon out the sump of the machine. Have you considered an air-admittance valve? Will make a noise, but shouldn't be excessive.

Considering the price of a HepVo, have you considered that if you run the waste hose from the machine up before going down into the drain, that should prevent backflow too?