Glycerine filled manometer

[asalcedo]

I need to install a manometer to measure the mains water pressure at
home (0 to 6 bar scale is enough)

Since a couple of regular manometers have failed (started reading less
than actual pressure) I got a known brand glycerine filled one.

1. No vibrations are expected. Will the glycerine manometer still give
accurate readings for longer?

2. I am supposed to cut open the tip of a rubber plug at the top of the
meter. Why is this required?

3. Can I install it horizontally without cutting the plug?

4. Can I install it horizontally with a small (pin size) opening?

Thanks,

Antonio




--
asalcedo

[Tim Watts]

Do you know how a moanometer works?

Not being funny - but some of your questions are at odds with that :-o
--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal coverage

Reading this on the web? See:
http://wiki.diyfaq.org.uk/index.php?title=Usenet

[Jeremy Nicoll - news posts]

asalcedo <asalcedo...@diybanter.com> wrote:

>2. I am supposed to cut open the tip of a rubber plug at the top of the
>meter. Why is this required?

As water pressure pushes the glycerine up the tube, the air space beyond it
will - if you don't cut the tip - compress. I would expect the compressing
air to push back against the glycerine column so it might not move as high
as it should, thus giving a falsely low reading. Possibly in exceptional
circumstances the tube might burst.

>3. Can I install it horizontally without cutting the plug?

Only if you want the glycerine to be pushed out of the tube.

Also the water pressure pushes against (I assume) a known (calibrated?)
weight of glycerine - if you let some of that glycerine out the water
pressure will push the smaller amount of glycerine that's still there
further next time, thus giving a misleadingly high reading.

>4. Can I install it horizontally with a small (pin size) opening?

No. You need the weight of the glycerine to oppose the water pressure.



--
Jeremy C B Nicoll - my opinions are my own.

Email sent to my from-address will be deleted. Instead, please reply
to newsre...@wingsandbeaks.org.uk replacing "aaa" by "284".

[Richard]

"Tim Watts" wrote in message
news:bbv1fa-...@squidward.local.dionic.net...

>
>On Wednesday 28 August 2013 19:49 asalcedo wrote in uk.d-i-y:
>
>>
>> I need to install a manometer to measure the mains water pressure at
>> home (0 to 6 bar scale is enough)
>>
>> Since a couple of regular manometers have failed (started reading less
>> than actual pressure) I got a known brand glycerine filled one.
>>
>> 1. No vibrations are expected. Will the glycerine manometer still give
>> accurate readings for longer?
>>
>> 2. I am supposed to cut open the tip of a rubber plug at the top of the
>> meter. Why is this required?
>>
>> 3. Can I install it horizontally without cutting the plug?
>>
>> 4. Can I install it horizontally with a small (pin size) opening?
>>
>> Thanks,
>>
>> Antonio
>>
>
>Do you know how a moanometer works?
>
>Not being funny - but some of your questions are at odds with that :-o

It's an iphone app apparently
http://www.sooperdd.com/portfolio/moanometer/

Not to be confused with the nagometer
https://itunes.apple.com/gb/app/nag-o-meter/id317038818?mt=8

HTH

[Bob Minchin]

Tim Watts wrote:
> On Wednesday 28 August 2013 19:49 asalcedo wrote in uk.d-i-y:
>
>>
>> I need to install a manometer to measure the mains water pressure at
>> home (0 to 6 bar scale is enough)
>>
>> Since a couple of regular manometers have failed (started reading less
>> than actual pressure) I got a known brand glycerine filled one.
>>
>> 1. No vibrations are expected. Will the glycerine manometer still give
>> accurate readings for longer?
>>
>> 2. I am supposed to cut open the tip of a rubber plug at the top of the
>> meter. Why is this required?
>>
>> 3. Can I install it horizontally without cutting the plug?
>>
>> 4. Can I install it horizontally with a small (pin size) opening?
>>
>> Thanks,
>>
>> Antonio
>>
>
> Do you know how a moanometer works?
>
> Not being funny - but some of your questions are at odds with that :-o
>

A manometer in the normal sense will be impractical for 6bar (some 60m
metres of height being needed.
Having googled, it seems that people are selling rotary spring pressure
gauges and calling them manometers. Some of these have the needle and
mechanism immersed in glycerine to damp out rapid fluctuations.
Have to admit that most of the questions asked by the OP are rather
strange though.

[Jeremy Nicoll - news posts]

Bob Minchin <bob.minc...@YOURHATntlworld.com> wrote:

>A manometer in the normal sense will be impractical for 6bar (some 60m
>metres of height being needed.

Oops; good point. I was thinking of doctors' mercury-filled manometers...

[Tim Watts]

Ah ha...

[Dave Liquorice]

On Wed, 28 Aug 2013 21:08:27 +0100, Jeremy Nicoll - news posts wrote:

> Also the water pressure pushes against (I assume) a known (calibrated?)
> weight of glycerine - if you let some of that glycerine out the water
> pressure will push the smaller amount of glycerine that's still there
> further next time, thus giving a misleadingly high reading.

Considering the OP mentioned pressures up to 6 bar, glycerine must be
pretty dense stuff considering 1 bar will only support a 30 inch high
column of mercury...

Now a glycerine filled pressure gauge is a different thing. Googling
about there are loads of references to "glycerine filled manometers"
that, IMHO, should be called "glycerine filled pressure gauges".

--
Cheers
Dave.

[Tim Watts]

Mercury would work :)

[Bob Minchin]

You would still need a 4m column of the stuff for 6 bar!

[Brian Gaff]

Well all the ones I saw when I worked in a lab had little notes saying
please install in a vertical position, so you might find yours says this as
well.
Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email: bri...@blueyonder.co.uk
______________________________________________________________________________________________________________


"asalcedo" <asalcedo...@diybanter.com> wrote in message
news:asalcedo...@diybanter.com...

[asalcedo]

'Jeremy Nicoll - news posts[_2_ Wrote:
> ;3113630']asalcedo asalcedo...@diybanter.com wrote:
> -

> 2. I am supposed to cut open the tip of a rubber plug at the top of the

> meter. Why is this required?-

>
> As water pressure pushes the glycerine up the tube, the air space beyond
> it
> will - if you don't cut the tip - compress. I would expect the
> compressing
> air to push back against the glycerine column so it might not move as
> high
> as it should, thus giving a falsely low reading. Possibly in
> exceptional
> circumstances the tube might burst.

> -
> 3. Can I install it horizontally without cutting the plug?-

>
> Only if you want the glycerine to be pushed out of the tube.
>
> Also the water pressure pushes against (I assume) a known (calibrated?)
> weight of glycerine - if you let some of that glycerine out the water
> pressure will push the smaller amount of glycerine that's still there
> further next time, thus giving a misleadingly high reading.
>

> -
> 4. Can I install it horizontally with a small (pin size) opening?-

>
> No. You need the weight of the glycerine to oppose the water pressure.
>
>
>
> --
> Jeremy C B Nicoll - my opinions are my own.
>
> Email sent to my from-address will be deleted. Instead, please reply
> to newsre...@wingsandbeaks.org.uk replacing "aaa" by "284".

These answers do not reflect how the type of glycerine manometer that I
am referring to works. And are not accurate as a consequence.

A glycerine manometer is just a normal pressure gauge that uses a
Bourdon tube in a casing that is filled with glycerine after it has been
calibrated

'Do you know how to make!! - Pressure Gauges -'
(http://www.youtube.com/watch?v=oCUbcVL22TI)

The glycerine is there just to dampen the rapid fluctuations of the
needle and mechanism under vibrations and/or rapid pressure changes. And
to prolong the life of the moving parts of the mechanism.

Since the glycerine is never in contact with the water the pressure
change in it will be minimal. Thus, I think it may work just as well
without cutting the plug and installing it in any direction.

Obviously, I am missing something




--
asalcedo

[Onetap]

On Wednesday, August 28, 2013 10:25:00 PM UTC+1, asalcedo wrote:

> A glycerine manometer is just a normal pressure gauge that uses a
>
> Bourdon tube in a casing that is filled with glycerine after it has been
>
> calibrated

A manometer is a transparent U-tube filled with a liquid (mercury, water, alcohol, etc.,) that measures pressure differences from the difference in the height of the liquid column.

I think the replies you got were not what you'd expected because your terminology was inaccurate.

I suspect your pressure gauge has been filled with glycerine and the filling plug has to be cut to stop thermal expansion of the glycerine breaking the glass. I can't think of any other reason. I don't know for sure, all the ones I've seen had a small air bubble and the plug wasn't meant to be cut.

[Dave Liquorice]

On Wed, 28 Aug 2013 23:25:00 +0200, asalcedo wrote:

> A glycerine manometer is just a normal pressure gauge that uses a
> Bourdon tube in a casing that is filled with glycerine after it has been
> calibrated

A bourdon tube works against the surrounding atmospheric pressure, so
if the gauge body is sealed it will misread. Presumably the sealed
rubber bung is there to stop the glycerine escaping in transit. You
then need to have a hole in it so the gauge body is at atmospheric
pressure when in use.

--
Cheers
Dave.

[harryagain]

"Jeremy Nicoll - news posts" <jn.nntp....@wingsandbeaks.org.uk> wrote
in message news:mpro.ms9dds...@wingsandbeaks.org.uk.invalid...

> Bob Minchin <bob.minc...@YOURHATntlworld.com> wrote:
>
>>A manometer in the normal sense will be impractical for 6bar (some 60m
>>metres of height being needed.
>
> Oops; good point. I was thinking of doctors' mercury-filled manometers...

That is a sphygmomanometer.

[harryagain]

"asalcedo" <asalcedo...@diybanter.com> wrote in message
news:asalcedo...@diybanter.com...
>

A manometer is a liquid column in tube device for measuring quite low
pressures.
ie millibars rather the bars.

Eg domestic natural gas pressures, Atmospheric pressure, blood pressure.

No good at all for mains water pressure.

[Tim Watts]

You could read it from an upstairs windows - I call "practical" :)

[Tim Watts]

Riiighht. So it is not actually a "manometer" then...

To me, a manometer is specifically a U-tube filled with a liquid.

[asalcedo]

'Dave Liquorice[_2_ Wrote:
> ;3113739']On Wed, 28 Aug 2013 23:25:00 +0200, asalcedo wrote:
> -

> A glycerine manometer is just a normal pressure gauge that uses a
> Bourdon tube in a casing that is filled with glycerine after it has
> been

> calibrated-

>
> A bourdon tube works against the surrounding atmospheric pressure, so
> if the gauge body is sealed it will misread. Presumably the sealed
> rubber bung is there to stop the glycerine escaping in transit. You
> then need to have a hole in it so the gauge body is at atmospheric
> pressure when in use.
>
> --
> Cheers
> Dave.

Leaving aside terminology, which, is good to learn, I have now the
answer, I think, to my question:

A Bourdon tube does measure the relative pressure between the fluids
inside and outside.

'Pressure measurement - Wikipedia, the free encyclopedia'
(http://en.wikipedia.org/wiki/Pressure_measurement)

If the casing was sealed in a place with very different atmospheric
pressure than the one where it is going to be used, there will be a less
accurate reading.

I doubt, though that this is relevant for my purposes. I am going to use
it a sea level and I am confident that the gauge was sealed in an
environment of only a few mbars difference. Versus the thousands of
mbars reading

The reason why, non glycerine filled pressure gauges do not have the
plug to be cut, is because they are not air tight.



As a consequence, I will install the gauge horizontally which will make
the installation much simpler and will check with a second manometer the
offset, if any.




--
asalcedo

[The Other Mike]

On Wed, 28 Aug 2013 22:18:27 +0100, Bob Minchin
<bob.minc...@YOURHATntlworld.com> wrote:

>Tim Watts wrote:
>
>> Mercury would work :)
>>
>You would still need a 4m column of the stuff for 6 bar!

Liquid Osmium.

--

[Bob Minchin]

True - but I live in a bungalow?

[Bob Minchin]

You will get on with asking questions much better if you learn from what
has been disclosed in this thread in that the device you are using is
NOT a manometer.

[Baz]

<Snip>>>

>>
>>
>>
> You will get on with asking questions much better if you learn from what
> has been disclosed in this thread in that the device you are using is NOT
> a manometer.

To be fair to the OP. If you think you know what a "glycerine filled
manometer" should be. Just pop "glycerine filled manometer" into Google.

Baz

[Steve Firth]

Bob Minchin <bob.minc...@YOURHATntlworld.com> wrote:
[snip]

> True - but I live in a bungalow?

Are you not sure?

--
<•DarWin><|
_/ _/

[Bob Minchin]

Indeed, That is how I came to realise what the OP was on about.
However just because others use the wrong name and google indexes those
erroneous references does not make it correct.

[asalcedo]

'Bob Minchin[_4_ Wrote:
> ;3113887']asalcedo wrote:-
> 'Dave Liquorice[_2_ Wrote:-

> ;3113739']On Wed, 28 Aug 2013 23:25:00 +0200, asalcedo wrote:
> -
> A glycerine manometer is just a normal pressure gauge that uses a
> Bourdon tube in a casing that is filled with glycerine after it has
> been
> calibrated-
>
> A bourdon tube works against the surrounding atmospheric pressure, so
> if the gauge body is sealed it will misread. Presumably the sealed
> rubber bung is there to stop the glycerine escaping in transit. You
> then need to have a hole in it so the gauge body is at atmospheric
> pressure when in use.
>
> --
> Cheers

> Dave.-

>
> Leaving aside terminology, which, is good to learn, I have now the
> answer, I think, to my question:
>
> A Bourdon tube does measure the relative pressure between the fluids
> inside and outside.
>
> 'Pressure measurement - Wikipedia, the free encyclopedia'

> ('Pressure measurement - Wikipedia, the free encyclopedia'
> (http://en.wikipedia.org/wiki/Pressure_measurement))

>
> If the casing was sealed in a place with very different atmospheric
> pressure than the one where it is going to be used, there will be a
> less
> accurate reading.
>
> I doubt, though that this is relevant for my purposes. I am going to
> use
> it a sea level and I am confident that the gauge was sealed in an
> environment of only a few mbars difference. Versus the thousands of
> mbars reading
>
> The reason why, non glycerine filled pressure gauges do not have the
> plug to be cut, is because they are not air tight.
>
>
>
> As a consequence, I will install the gauge horizontally which will
> make
> the installation much simpler and will check with a second manometer
> the
> offset, if any.
>
>
>

> -

> You will get on with asking questions much better if you learn from what
>
> has been disclosed in this thread in that the device you are using is
> NOT a manometer.

Ok, I agree, in English, which is not my native language, according to
Wikipedia: "Instruments used to measure pressure are called pressure
gauges or vacuum gauges.

A manometer could also refer to a pressure measuring instrument, usually
limited to measuring pressures near to atmospheric"

But Merriam Webster dictionary defines it as "an instrument (as a
pressure gauge) for measuring the pressure of gases and vapors" which is
as broad a definition as the one in other languages.

But, it was obvious that the broader definition applied here since I was
talking of pressure readings far from atmospheric.





Leaving that aside, do we agree that a glycerine filled pressure gauge
can be installed in any position keeping the enclosure air tight for
reading of several bars?




--
asalcedo

[Gazz]

"harryagain" <harry...@btinternet.com> wrote in message
news:kvmosr$j9d$7...@dont-email.me...

i don't think he cares, he's been told enough times it is a pressure gauge,
not a manometer, but he still refuses to call it by it's proper name,

I think all he wants is for someone to say 'yes, it will work fine how you
propose' so that when the glycerin leaks out and makes a mess, or the gauge
becomes inaccurate, he can blame someone else for telling him it would be
ok,

Maybe if he bought a decent quality gauge in the first place he wouldn't
have this 'problem'


Not sure really why he 'needs' to measure the water pressure at home, it
either comes out the taps or it dosent, what's it matter if for 2 seconds a
week it's half a bar below 'normal' pressure,

He says a couple of 'regular' gauges he's used before started reading less
than actual pressure, how is he reading the 'actual pressure' and why dosent
he just use that for the reading?
or pop the front bezel off the gauges and twist the needle to the correct
position :)

[Baz]

"Baz" <bras...@REMOVEmsn.com> wrote in message
news:Mo-dnW-4tpaJuILP...@bt.com...

I would be surprised if you need a glycerine filled gauge in a domestic
application.
The glycerine filled is to protect the gauge from excessive vibration or
pulsing.
If you have either, that is so bad that you need glycerine filled it WILL
damage the rest of your system.

Baz

[Dave Liquorice]

On Thu, 29 Aug 2013 09:17:12 +0200, asalcedo wrote:

> A Bourdon tube does measure the relative pressure between the fluids
> inside and outside.

<snip>

> If the casing was sealed in a place with very different atmospheric
> pressure than the one where it is going to be used, there will be a less
> accurate reading.

It'll vary with atmospheric pressure anyway, that has a range of
about 50 mb, or about 5% @ 1 bar, 0.8% @ 6 bar.

> As a consequence, I will install the gauge horizontally which will make
> the installation much simpler and will check with a second manometer the
> offset, if any.

But without having the casing vented to the atmosphere when the tube
expands the pressure in the casing will rise and affect the reading.
They are designed to be used vented. I suspect any offset will be
non-linear as the pressure in the casing rises.

--
Cheers
Dave.

[asalcedo]

'Dave Liquorice[_2_ Wrote:
> ;3113997']On Thu, 29 Aug 2013 09:17:12 +0200, asalcedo wrote:
> -

> A Bourdon tube does measure the relative pressure between the fluids

> inside and outside.-
> snip-

> If the casing was sealed in a place with very different atmospheric
> pressure than the one where it is going to be used, there will be a
> less

> accurate reading.-

>
> It'll vary with atmospheric pressure anyway, that has a range of
> about 50 mb, or about 5% @ 1 bar, 0.8% @ 6 bar.

> [color=blue][i]
>

Agreed

'Dave Liquorice[_2_ Wrote:
> ;3113997']On Thu, 29 Aug 2013 09:17:12 +0200, asalcedo wrote:
> [color=blue][i]

>
> But without having the casing vented to the atmosphere when the tube
> expands the pressure in the casing will rise and affect the reading.
> They are designed to be used vented. I suspect any offset will be
> non-linear as the pressure in the casing rises.
>
> --
> Cheers
> Dave.

Disagree. When under pressure, the tube deforms (straightens up) but
does not expand meaningfully. There is no change in pressure inside the
casing




--
asalcedo

[asalcedo]

Gazz;3113950 Wrote:
> "harryagain" harry...@btinternet.com wrote in message

> news:kvmosr$j9d$7...@dont-email.me...-

>
> "asalcedo" asalcedo...@diybanter.com wrote in message

> news:asalcedo...@diybanter.com...-

>
> I need to install a manometer to measure the mains water pressure at
> home (0 to 6 bar scale is enough)
>
> Since a couple of regular manometers have failed (started reading less
> than actual pressure) I got a known brand glycerine filled one.
>
> 1. No vibrations are expected. Will the glycerine manometer still give
> accurate readings for longer?
>
> 2. I am supposed to cut open the tip of a rubber plug at the top of the
> meter. Why is this required?
>
> 3. Can I install it horizontally without cutting the plug?
>
> 4. Can I install it horizontally with a small (pin size) opening?
>

> Thanks,-

>
> A manometer is a liquid column in tube device for measuring quite low
> pressures.
> ie millibars rather the bars.
>
> Eg domestic natural gas pressures, Atmospheric pressure, blood
> pressure.
>

> No good at all for mains water pressure.-

>
> i don't think he cares, he's been told enough times it is a pressure
> gauge,
> not a manometer, but he still refuses to call it by it's proper name,
>
> I think all he wants is for someone to say 'yes, it will work fine how
> you
> propose' so that when the glycerin leaks out and makes a mess, or the
> gauge
> becomes inaccurate, he can blame someone else for telling him it would
> be
> ok,
>
> Maybe if he bought a decent quality gauge in the first place he wouldn't
>
> have this 'problem'
>
>
> Not sure really why he 'needs' to measure the water pressure at home, it
>
> either comes out the taps or it dosent, what's it matter if for 2
> seconds a
> week it's half a bar below 'normal' pressure,
>
> He says a couple of 'regular' gauges he's used before started reading
> less
> than actual pressure, how is he reading the 'actual pressure' and why
> dosent
> he just use that for the reading?
> or pop the front bezel off the gauges and twist the needle to the
> correct
> position :)

The tone of this reply is not what one should expect in this forum.

The house is connected to a pump that supplies up to 10 bar. There will
be a quality pressure reducing valve which does come with a pressure
regulation screw mechanism.

I want to have an additional pressure gauge as a redundant safety to
avoid bursting or damaging the plumbing in the house in the event the
pressure reducing valve fails. Or to make sure that the pressure is
above the level required by certain equipment in the house (but may be
you could tell that by opening the tap, I cannot)



The pressure gauge that I first got for the pressure reducing valve has
failed as confirmed by a Monument Tools Mains Water Pressure Test Gauge
connected to a tap which reads the same as the pressure setting in the
valve.



Obviously a fixed pressure gauge is a better solution than the Monument
Tools tap one, if anything because I may have to use the tap for other
purposes. Or do you not agree with that either?

Now, the glycerin gauges that I have seen have the 1/4" BSP thread only
at the bottom, which means that if I screw it into the horizontal thread
in the body of the pressure reducing valve it will be in a horizontal
position. I am trying to avoid cutting the pipe or other more
complicated solution to install the pressure gauge in a vertical
position.


By the way, pressure gauges do fail, even quality ones, I once had the
two pressure gauges in two brand new Worcester Bosch boilers fail at the
same time, which caused a major problem.




--
asalcedo

[Tim Watts]

It's a USENET newsgroup - not a forum...

And I've seen a lot worse for tone :-o

[PeterC]

Is that Donny Osmium or one of the others?
--
Peter.
The gods will stay away
whilst religions hold sway

[Dave Liquorice]

On Thu, 29 Aug 2013 21:35:36 +0100, Tim Watts wrote:

>> The tone of this reply is not what one should expect in this
forum.
>
> It's a USENET newsgroup - not a forum...

I'd previously missed the OP was a diybanter leach, principally
because I didn't understand the questions with the doubtful
terminology. So chose to, initially, ignore it.

As the OP rejects anything said, they appear to have made their mind
up before posting anyway. Don't know why I bothered TBH.

> And I've seen a lot worse for tone :-o

Indeed, it's been positively polite.

--
Cheers
Dave.

[Gazz]

>
> The tone of this reply is not what one should expect in this forum.
>

Then may one politely request that one goes forth and multiplies, you
insolent vagina!

[Rick Hughes]

On 28/08/2013 20:23, Tim Watts wrote:
> On Wednesday 28 August 2013 19:49 asalcedo wrote in uk.d-i-y:
>
>>

>> I need to install a manometer to measure the mains water pressure at
>> home (0 to 6 bar scale is enough)
>>
>> Since a couple of regular manometers have failed (started reading less
>> than actual pressure) I got a known brand glycerine filled one.
>>
>> 1. No vibrations are expected. Will the glycerine manometer still give
>> accurate readings for longer?
>>
>> 2. I am supposed to cut open the tip of a rubber plug at the top of the
>> meter. Why is this required?
>>
>> 3. Can I install it horizontally without cutting the plug?
>>
>> 4. Can I install it horizontally with a small (pin size) opening?
>>

>> Thanks,
>>
>> Antonio
>>
>
> Do you know how a moanometer works?

My wife hits 9.9 reading frequently

[PeterC]

%?

[aana...@gmail.com]

where-can-i-buy-glycerin-today.blogspot.com

here you find more info that you can handle

[The Medway Handyman]

Shouldn't that be personometer?

>


--
Dave - The Medway Handyman www.medwayhandyman.co.uk

[charles]

In article <BhyTw.127099$LW6....@fx09.am4>,

The Medway Handyman <davi...@blueyonder.co.uk> wrote:
> Shouldn't that be personometer?

still sexist - should be "perchildmeter"

--
From KT24 in Surrey

Using a RISC OS computer running v5.18

[meow...@care2.com]

a rather ineffective strategy. Cheaper, simpler more effective more reliable measures would be better


NT