Pipe - expansion tank to heater circuit return

[widdowson2008]

Think what a venturi does.....it just speeds up the flow......big pipe to small pipe...same effect (sort of)

I think you're trying to convert the unconvertible here Haydn cos I still can't see what I'm saying is wrong - sorry. I'm a lost cause. , but thanks for trying.
As a matter of interest, I trawled and found this (and I quote) which sort of suggests that what I'm getting at is not entirely a load of rhubarb.
Restriction orifice plates can be used as a simple pressure reducing device, or to limit the flow rate in a pipeline.
see
http://www.rototherm.co.uk/ROP_2007.pdf

[Northern Bongolow]

Think what a venturi does.....it just speeds up the flow......big pipe to small pipe...same effect (sort of)

I think you're trying to convert the unconvertible here Haydn cos I still can't see what I'm saying is wrong - sorry. I'm a lost cause. , but thanks for trying.
As a matter of interest, I trawled and found this (and I quote) which sort of suggests that what I'm getting at is not entirely a load of rhubarb.
Restriction orifice plates can be used as a simple pressure reducing device, or to limit the flow rate in a pipeline.
see
http://www.rototherm.co.uk/ROP_2007.pdf

that is right haydn, but as well as speeding up the flow when it enters the venturi it also lowers the pressure,this is the priciple that a spray pot works on,it sucks the paint up from the pot.
steve that is exactly what my next plan involves,well--- me and my teacher .
looking at reducing the exit flow from the head thus speeding up the flow and reducing pressure. dangerous game though

[The Great Pretender]

Restriction orifice plates can be used as a simple pressure reducing device, or to limit the flow rate in a pipeline.
see
http://www.rototherm.co.uk/ROP_2007.pdf

I agree you are correct it can do both..................But PLEASE EXPLAIN HOW IT CAN DO BOTH IN A SEALED SYSTEM

[widdowson2008]

Restriction orifice plates can be used as a simple pressure reducing device, or to limit the flow rate in a pipeline.
see
http://www.rototherm.co.uk/ROP_2007.pdf

I agree you are correct it can do both..................But PLEASE EXPLAIN HOW IT CAN DO BOTH IN A SEALED SYSTEM

Mel - If I knew the answer to that, then I needn't have asked the question in the first place. What folk have come up with so far is statements. What I was rather hoping for is is an explanation.
However, you now agree that it CAN 'limit the flow rate in a pipeline'. So why is my simple suggetion not valid? ... that a reduction in the flow will result in coolant remaning in the Xtank longer, and giving it more time to dispel any air. Sounds logical to me.

[mikexgough]

... that a reduction in the flow will result in coolant remaning in the Xtank longer, and giving it more time to dispel any air. Sounds logical to me.

The degas system patent.....shows a flow restrictor in it....but after the degas tank, however..IMHO..no reason why the flow should not be retricted at the tank.....must read the degas tank patent later to see if there are any pointers....... and your thoughts are what I suggested 2 yrs ago after I had an issue ...... got to go now...looking at a 1220cc 4 pot air cooled motor for a Van Clee car in an hour...

[widdowson2008]

... that a reduction in the flow will result in coolant remaning in the Xtank longer, and giving it more time to dispel any air. Sounds logical to me.

The degas system patent.....shows a flow restrictor in it....but after the degas tank, however..IMHO..no reason why the flow should not be retricted at the tank.....must read the degas tank patent later to see if there are any pointers....... and your thoughts are what I suggested 2 yrs ago after I had an issue ...... got to go now...looking at a 1220cc 4 pot air cooled motor for a Van Clee car in an hour...

Strictly speaking Mike, the restriction IS AFTER the expansion tank (outlet). See what you can come up with - I'll be interested.

[The Great Pretender]

Mel - If I knew the answer to that, then I needn't have asked the question in the first place. What folk have come up with so far is statements. What I was rather hoping for is is an explanation.
However, you now agree that it CAN 'limit the flow rate in a pipeline'. So why is my simple suggetion not valid? ... that a reduction in the flow will result in coolant remaning in the Xtank longer, and giving it more time to dispel any air. Sounds logical to me.

Sorry Steve I never said restrictors couldn't limit flow in a pipe. Your simple flow test shows how a smaller size outlet reduces flow as most people would understand. I'm surprised at your stance on this, are you being pedantic or are you really having a problem understanding the correlation between flow, speed and pressure in the cooling system?
You haven't just had statements, you were offered an incite into other peoples understandings of the small pipes relationship with the system.
I posted the link to Bernoulli's principle, that was his statement, do you disagree with that? Did you read it and follow the links? If you did you should understand why your simple suggestion is not valid. Until you do that you will not understand how all the circuits in the Cooling system inter relate and need the same resistance at all operating temperatures and flow (pump speed) to work.
As for an explanation, sorry, but I can point you in the right direction for you to understand how a closed multi loop system works and how to proportion resistance not restriction.
If you do bother to read it, disregard the 1.5m/s as it relates to noise created in copper pipes due to pump speed, not relative to the Bongo

http://www.gasheating.co.uk/pipesizing.html

[haydn callow]

that light green typo is doing my eyes in even more than they already are....

[The Great Pretender]

that light green typo is doing my eyes in even more than they already are....

Sorry Haydn, Just for you.

Sorry Steve I never said restrictors couldn't limit flow in a pipe. Your simple flow test shows how a smaller size outlet reduces flow as most people would understand. I'm surprised at your stance on this, are you being pedantic or are you really having a problem understanding the correlation between flow, speed and pressure in the cooling system?
You haven't just had statements, you were offered an incite into other peoples understandings of the small pipes relationship with the system.
I posted the link to Bernoulli's principle, that was his statement, do you disagree with that? Did you read it and follow the links? If you did you should understand why your simple suggestion is not valid. Until you do that you will not understand how all the circuits in the Cooling system inter relate and need the same resistance at all operating temperatures and flow (pump speed) to work.
As for an explanation, sorry, but I can point you in the right direction for you to understand how a closed multi loop system works and how to proportion resistance not restriction.
If you do bother to read it, disregard the 1.5m/s as it relates to noise created in copper pipes due to pump speed, not relative to the Bongo

http://www.gasheating.co.uk/pipesizing.html

[haydn callow]

thank you

[The Great Pretender]

thank you

[The Great Pretender]

... that a reduction in the flow will result in coolant remaning in the Xtank longer, and giving it more time to dispel any air. Sounds logical to me.

The degas system patent.....shows a flow restrictor in it....but after the degas tank, however..IMHO..no reason why the flow should not be retricted at the tank.....must read the degas tank patent later to see if there are any pointers....... and your thoughts are what I suggested 2 yrs ago after I had an issue ...... got to go now...looking at a 1220cc 4 pot air cooled motor for a Van Clee car in an hour...

I spent ages trying to find the patent for the degassing tank, no luck. Any chance of a link?
I have a suspicion about that res.....x...........rest....x..........LOL...........liquid to air motivator.
I may be completely wrong but it would be nice to see how the designer expected it to work.

[widdowson2008]

Been out of this post for a week or so - not through choice - I've been on a jolly in Norfolk. However, I'm back
Read and re-read through the replies, read Mels links re: Bernoulli, taken on board Mikes input and I'm afraid I still can't see any other function for the small pipe other than to balance the pressure throughout the system. (without this pipe link, I would have thought the pressure in the expansion tank would be greater)
I was looking for a simple answer, but perhaps it is more involved than I thought. . I'll sit back and wait for further input.

[The Great Pretender]

Thanks for the links to the patent Mike very informative.
The Bongo system is different though, do you think it was their way of circumnavigating the patent? Or is there one for the Bongo system?
I have thought about why there is no expansion tank on the Bongo and like the clever way the patent built one in, maybe it would contravene the patent if used on the Bongo?
I'm sorry but if we are all singing from the same song sheet (patent) the fitment on the return from the degassing tank is not a restrictor but shows how clever Mazda were by building it into the tank.

[mikexgough]

Thanks for the links to the patent Mike very informative.
The Bongo system is different though, do you think it was their way of circumnavigating the patent? Or is there one for the Bongo system?
I have thought about why there is no expansion tank on the Bongo and like the clever way the patent built one in, maybe it would contravene the patent if used on the Bongo?
I'm sorry but if we are all singing from the same song sheet (patent) the fitment on the return from the degassing tank is not a restrictor but shows how clever Mazda were by building it into the tank.

No worries Mel...heck of a read....... the original design was Toyota and it's still used in a similar format today in most cars. I reckon your on the ball with Mazda building it into the tank and that would be the way as not to cause patent issues with Toyota.... I have trawled everywhere for a pukka Bongo patent/blueprint to no sucess...yet..
The degas tank patent shows how the tank works and how the chambers do the job, obviously the number of chambers/sizes of is system dependent.