Anti-syphon loops

[prv]

Agree entirely but I still reckon that you couldn't pump enough water through the small inlet pipe to fill the larger outlet pipe.

Don't forget you're starting with a bowl full of water. Even if there was nothing at all coming in through the flush pipe, you've still got about ten or more good solid strokes of the discharge pump (same bore as the pipe). It takes twenty strokes to clear my discharge pipe, and if I have the flush flushing then every one of those strokes is 100% water (the water level doesn't really drop, and certainly stays well above the outlet).

Pete

 

[coopec]

I bought my anti syphnon loops from Lee Marine (HK) for $A10.50 but apparently they don't sell them anymore. You might like to look at their eBay site though as I think they do some good deals.

http://www.ebay.com.au/sch/m.html?_...46732.m570.l1313.TR0.TRC0.H0.X&_nkw=&_sacat=0

The cheapest loops I came across are from Amazon but I think they are a rip-off
http://www.amazon.co.uk/Marine-Toilet-Vented-Siphon-Device/dp/B004TKZU5W

 

[coopec]

WELL, WELL, WELL!!!

Here is an anti siphon loop from LeiMarine for $A9.10

http://www.leimarine.com/index.php/...oops-size-3-4-for-marine-yacht-new-stock.html

http://www.leimarine.com/index.php/...t-anti-siphon-vented-loop-1-new-bta00202.html

 

[2copplane]

I don't have any anti syphons fitted, but I am thinking about it. I assume they work by a small valve sealing under positive pressure and prevent a syphon by opening under neutral or negative. So to fit on the inlet pipe it would go in the pipe that goes from the pump to the back of the head and not in the long pipe from the hull fitting to pump.

Otherwise it would just suck air in?

 

[sailorman]

I don't have any anti syphons fitted, but I am thinking about it. I assume they work by a small valve sealing under positive pressure and prevent a syphon by opening under neutral or negative. So to fit on the inlet pipe it would go in the pipe that goes from the pump to the back of the head and not in the long pipe from the hull fitting to pump.

Otherwise it would just suck air in?

if it sucks air then the vacuum breaks as in my Lavac

 

[prv]

if it sucks air then the vacuum breaks as in my Lavac

That's a bit of a red herring though, as the lavac operates very differently to most toilets.

2copplane has described the usual situation exactly.

Pete

 

[TonyBuckley]

I have one fitted but only after my insurance company insisted. They lost a boat that started to siphon from the wash created by a passing ship. They told me it is a standard condition for all their policies now so worth checking. That's with Pantaenius.

 

[sailorman]

That's a bit of a red herring though, as the lavac operates very differently to most toilets.

2copplane has described the usual situation exactly.

Pete

It still has a vacuum break & loops on in & outlet pipes

#27
it the loops go to the deck hd how can that happen. Its only possible with loops of insufficient height

 

[VicS]

I don't have any anti syphons fitted, but I am thinking about it. I assume they work by a small valve sealing under positive pressure and prevent a syphon by opening under neutral or negative. So to fit on the inlet pipe it would go in the pipe that goes from the pump to the back of the head and not in the long pipe from the hull fitting to pump.

Otherwise it would just suck air in?

Thats right. You might get away with it if there is just a small pin hole in the pipe between seacock and pump but if its any larger it will admit so much air that flushing will be impaired

if it sucks air then the vacuum breaks as in my Lavac

It still has a vacuum break & loops on in & outlet pipes

#27
it the loops go to the deck hd how can that happen. Its only possible with loops of insufficient height

A big difference, I suspect, in the performance of the diaphragm pump used with a Lavac and the plunger pump fitted to Jabscos and the like

That's a bit of a red herring though, as the lavac operates very differently to most toilets.

2copplane has described the usual situation exactly.

Pete

S' right

 

[LittleSister]

A big difference, I suspect, in the performance of the diaphragm pump used with a Lavac and the plunger pump fitted to Jabscos and the like

Thanks for the clarification. I stand corrected.

(or should that be 'Thanks for the correction. I stand clarified?)

 

[Graham_Wright]

I have decided to just have small bleed pipes connected to the black water tank vent.

However, trying to knit all the pipes together - three two-way-and-off diverters and two sea valves - the knitting is something else!

If I can source a large bore U bend, that would make the route from the pan to valve much more sanitary(!).

Standard plumbing fittings?

Off to B&Q.

 

[coopec]

I have decided to just have small bleed pipes connected to the black water tank vent.

However, trying to knit all the pipes together - three two-way-and-off diverters and two sea valves - the knitting is something else!

If I can source a large bore U bend, that would make the route from the pan to valve much more sanitary(!).

Standard plumbing fittings?

Off to B&Q.

Why not us standard plumbing fittings? (I think you will find they measure plumbing fittings differently to pipe fittings. One is internal measurement and the other is external)

The "S" bend under a sink could be your large bore "U" bend?

What are the "bleed pipes connected to the black water tank vent" for? What are yoi going to bleed out of them?

 

[Graham_Wright]

Why not us standard plumbing fittings? (I think you will find they measure plumbing fittings differently to pipe fittings. One is internal measurement and the other is external)

The "S" bend under a sink could be your large bore "U" bend?

That was my thought hence the ref. to B&Q (may be a British thing?!)

What are the "bleed pipes connected to the black water tank vent" for?

The syphon breaks

What are yoi going to bleed out of them?

Hopefully nothing - it should be going in!

I have a colleague who produces components for the Morgan Car Company including bull bars. These are the right diameter and he can bend to silly radii. The material will be 304 rather than 316 but that won't have to matter.

 

[coopec]

That was my thought hence the ref. to B&Q (may be a British thing?!)

Hopefully nothing - it should be going in!

I have a colleague who produces components for the Morgan Car Company including bull bars. These are the right diameter and he can bend to silly radii. The material will be 304 rather than 316 but that won't have to matter.

Wouldn't your bleeding tube allow smells to come out of the system?

You have bull bars in the UK!! We have lots of cattle stations around 5000 sq mile (13500 sq kms) each and a lot of the area is not fenced off along the roads. So we can hit kangaroos, wild horses, camels, emus and of course cattle).

I am getting an anti siphon loop made up right now for my motor by a guy who made up my pushpit and pullpit. It will be made from 316 ss. I wonder how long that would last with corrosive black water?

Did you see this article.
http://www.sbmar.com/articles/designing_a_marine_exhaust_system/


Anit-Siphon Loops - How do they work ? - Yachting and Boating World
www.ybw.com › ... › Forum › Practical Boat Owner's Reader to Reader‎
Mar 1, 2005 - 10 posts - ‎7 authors
I am replacing hoses in the heads on my boat and I am confused by the anti-siphon loops, the toilet bowl is below the water line and both the ...
Anti-syphon loops 2 posts 3 Mar 2014
How does an anti siphon valve actually work. 10 posts14 Apr 2012
Jabsco toilet water inlet anti syphon loop 10 posts 2 Apr 2011
Anti Siphon Loop Squirts Water??? 10 posts 3 Nov 2007

B&Q must be a hardware chain? In Australia it would be "Bunnings"

 

[Graham_Wright]

Wouldn't your bleeding tube allow smells to come out of the system?

No; it will be connected into the black water yank vent line.

You have bull bars in the UK!!

They normally injure people here![/QUOTE]

I am getting an anti siphon loop made up right now for my motor by a guy who made up my pushpit and pullpit. It will be made from 316 ss. I wonder how long that would last with corrosive black water?

The tank si the same material and I am 74!

Did you see this article.
http://www.sbmar.com/articles/designing_a_marine_exhaust_system/

Interesting. My engine exhaust is all Vetus fitted including the swan neck. The anti syphon on that feeds into the cockpit.

Anit-Siphon Loops - How do they work ? - Yachting and Boating World
www.ybw.com › ... › Forum › Practical Boat Owner's Reader to Reader‎
Mar 1, 2005 - 10 posts - ‎7 authors
I am replacing hoses in the heads on my boat and I am confused by the anti-siphon loops, the toilet bowl is below the water line and both the ...
Anti-syphon loops 2 posts 3 Mar 2014
How does an anti siphon valve actually work. 10 posts14 Apr 2012
Jabsco toilet water inlet anti syphon loop 10 posts 2 Apr 2011
Anti Siphon Loop Squirts Water??? 10 posts 3 Nov 2007

B&Q must be a hardware chain? In Australia it would be "Bunnings"

Thanks for the steers. You must be up in the middle of the night!

 

[Graham_Wright]

Received my U bend!

4" radius in 3mm thick 316. Incredible! No wrinkles, no flats.

 

[Graham_Wright]

Received my U bend!

4" radius in 3mm thick 316. Incredible! No wrinkles, no flats.

Had a problem loading the other photo.

 

[bikesherpa]

My boat (1998 Comar Genesi 43) is originally equipped with nicely crafted SS 316 double vented loops in both heads.

However, I have found recently that one discharge vented loop pipe had a small hole, certainly due to corrosive black water. The advantage of SS is that I could easily repair it by welding the hole.