Loo designs

[Hindhaugh]

I need to replace a traditional toilet with a modern flush loo. To the eye the actual modern French loo sold in brico stores etc looks similar if not identical the the UK product, other than the cistern that may have a smaller water capacity and a half flush feature? Is this a correct assumption?

[Alcazar]

Nearly right: it does a similar job, and fits together similarly, but the flush works differenly...................as I found to my cost when I fitted one, the cistern lid wouldn't come off and the instructions were INSIDE it.

The wife, (bless her), PULLED the lid off, and the gubbins inside flew everywhere. Once I FOUND it all again, it took me about half an hour WITH instructions, to put it all back into working order.

Alcazar

[Opel Fruit<P><BR>Opel Fruit, Dept. 53<P>]

The difference is as mentioned. The flush mechanism is simply gravity, whereas the UK design is for a syphon action. In theory, the gravity version lasts longer because they are simpler and require no diaphragm replacement from time to time. Interestingly (or not) the UK is moving toward the gravity system.

The flush buttons on the loos here are often have a screw collar around them which allows full removal of the lid.

There are two types of cistern valve used here these days. The first type, the cheapest, uses a variation of the ball float, substituted by a lump of polystyrene. Very susceptible to variations in mains pressure. The second one uses a vertical plastic float which is very compact and highly effective with no obvious problems with pressure variation.

[Gyn_Paul]

I'm always amazed that such a small float (either block of polystyrene or plastic float on a vertical slide) can generate sufficient 'push' to resist the pressure of 4 or 5 bar which - if the physics brain cell can be relied upon - must be something like 80-odd psi. It's all about mechanical advantage, I suppose.

p

And while I have Opel Fruit (or Punch)'s attention.... how does a pressure limiter, usually fitted just after the water compteur, work? I can understand how something can restrict the FLOW, but the standing pressure ??

[Hindhaugh]

Thanks for this everyone, as I thought I can now go ahead on October with peace of mind! Will now see if I can find anything on removing traditional earth floors...life is so interesting whan you have a house in France!

[Opel Fruit<P><BR>Opel Fruit, Dept. 53<P>]

Pressure reduction devices. Not to be confused with flow reduction (a tap!)(which most people do!)

The most effective way of making something reduce pressure of fluids is to use a 3 port device where there is an inlet, an outlet and a bleed off. This is how car oil pumps or fuel pressure regulator work. Once the pressure reaches a set level, a ball bearing or shuttle valve held in contact with the bleed off port opens and allows the excess pressure, in the form of the fluid to return to the sump or fuel tank. Clearly this is not practical with a water supply, since you cannot bleed the water off without it going to drain.

Theses devices work by closing off the outlet when the pressure exceeds the set value. They are usually noisy, since they "chatter" about the set point. They are usually rather inaccurate.

[VJ]

And if you want it from the professionals !!!!

Pressure Reducing Valve is an automatic control valve designed to reduce a higher inlet pressure to a lower constant outlet pressure regardless of fluctuating flow rates and/or varying inlet pressure.

It is a pilot controlled, hydraulically operated, diaphragm actuated globe valve in either the oblique (Y) or angle pattern design. Valve differential pressure powers the diaphragm actuator open or closed.

The lower control chamber is connected through a fixed orifice to the downstream pressure, which serves to cushion the closing of the valve.

The upper control chamber, which operates on a two-way control principle, has varying pressure produced by the regulating pilot and the pilot's internal upstream restriction needle valve.

The pressure regulating pilot senses downstream pressure and modulates open or closed. This varies the pressure in the upper control chamber causing the main valve to throttle thus maintaining constant delivery pressure.

When the downstream pressure falls below the pilot setting, the pilot opens, pressure in the upper control chamber decreases, and the main valve modulates open to increase downstream pressure and maintain pilot setting.

Should the downstream pressure rise above the pilot setting, the pilot closes, pressure in the upper chamber increases and the main valve throttles close to decrease downstream pressure to the pilot setting.

The Pressure Reducing pilot has an adjusting screw to preset the desired downstream pressure and an internal needle valve to control the closing speed.

[Opel Fruit<P><BR>Opel Fruit, Dept. 53<P>]

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