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OT Barometer Location
Hi all
I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Thanks Phil |
OT Barometer Location
"thescullster" wrote in message ... Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Not sure about the instrumentation but I don't think it would be a good idea to put antique oak woodwork above a radiator. mark |
OT Barometer Location
On Wed, 26 Jun 2013 15:35:21 +0100, "mark"
wrote: "thescullster" wrote in message ... Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Not sure about the instrumentation but I don't think it would be a good idea to put antique oak woodwork above a radiator. Especially if the barometer has a built-in thermometer :-) -- Frank Erskine |
OT Barometer Location
No certainly not it tends to crack.
Actually these are just a sealed bellows I think that operate a needle by clever gearing. If the unit is leaky though it will never work. I've not got one now but they dont seem to care where they are unless you have forced air air conditioning to keep pressure high, most houses are the same as outside. I see we are all supposed to be using Hecto Pascals now instead of Millibarrs etc. Ho hum, pass me that altimeter. Brian -- From the Sofa of Brian Gaff Reply address is active "mark" wrote in message o.uk... "thescullster" wrote in message ... Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Not sure about the instrumentation but I don't think it would be a good idea to put antique oak woodwork above a radiator. mark |
OT Barometer Location
Or indeed a hygrometer as mine had.
Brian -- From the Sofa of Brian Gaff Reply address is active "Frank Erskine" wrote in message ... On Wed, 26 Jun 2013 15:35:21 +0100, "mark" wrote: "thescullster" wrote in message ... Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Not sure about the instrumentation but I don't think it would be a good idea to put antique oak woodwork above a radiator. Especially if the barometer has a built-in thermometer :-) -- Frank Erskine |
OT Barometer Location
On Wed, 26 Jun 2013 15:29:40 +0100, thescullster wrote:
Does a heat source like a radiator change atmospheric pressure? Not that would be measurable by that instrument in a normal (non-air tight) house. B-) Can I mount this on a wall above a radiator and expect it to work? I wouldn't, as others have said the oak won't like it and if you are getting wide temperature variations (rad on v rad off) that could affect the readings as the works expand/contract. Try an find a place with a fairly stable temperature to be kind to the wood and the instrument. From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Well ATM the UK is under the influence of a high pressure and it's not changing very much at all. Normal sort of range would be about 29.25" to 30" of mercury (1000 to 1030 mb) changing from one to the other normally over couple/three days. Though it can change faster. These type of barometers might need a gentle tap to make the needle move properly to the current pressure reading. There also ought to be a small adjustment screw to compensate for your locations altitude, so the instrument reads "sea level" pressure. Now is not a bad time to check that as most of the country is pretty much at 1032 mb (30.5" Hg) Depending on how windy it is and how exposed/draughty your house is that can cause a few mb of reduced pressure inside by venturi effects of chimneys etc. I've noticed on several occasions when a gale suddenly stops there is a coresponding step up in the air pressure. -- Cheers Dave. |
OT Barometer Location
"thescullster" wrote in message ... Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Location will not affect the baro, but it will affect the thermometer and possibly the wood. Don't know much of aneroids, prefer mercury. As regards movement of the needle. Set baro in desired position. Align the cursor with the hand. Repeat at 10am every day of course. Note the movement of the hand over a 24hr period. If the swing is 30 deg or more- Sun hat if up, raincoat, hat & wellies if it's down. Do you have a dinghy? Just keep an eye on it for a few days. I suspect most aneroid baros would not be repairable. TBH, they're not worth it. I think the seller of the item you show is utterly and completely off trolley. Delete the first number, divide the remainder by two and you might be in the real world. hth Nick. |
OT Barometer Location
On 26/06/2013 15:29, thescullster wrote:
Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Thanks Phil The heat source doesn't change atmospheric pressure, but the pressure reading will cycle a little as the instrument temperature changes, something like 3% for a 10 degree C variation. If the needle isn't moving much it's likely that the bellows has a leak, or there is a problem in the (relatively fragile) linkage between the bellows and the needle. |
OT Barometer Location
thescullster was thinking very hard :
Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Thanks Phil Pressure is the same pressure irrespective, providing it is in the same geographical area. So mount it in any sensible location, but not over a radiator as that will affect the wood. You can calibrate it, by comparing it to your local weather station - note the pressure indicated by your instrument, at the times the pressures are suggested to be have measured, then compare your reading with what they suggest the pressure was at that paticular time. From that, you should be able to work out what your error was and make an adjustment. Best to do it when the pressure has been steady for a good while though, when the isobars are widely spaced / not much wind. -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk |
OT Barometer Location
"thescullster" wrote in message ... Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Thanks Phil Re the instrument itself, it measures air pressure. The only influence you have on it's reading is the altitude of your house. (Altitude also affects air pressure) Normal pressure is 1013mB.=760mm of Hg They often don't work because the stack of capsules inside develop cracks. It is and aneroid barometer. http://en.wikipedia.org/wiki/Baromet...oid_barometers There are specialist repairers of them |
OT Barometer Location
On 26/06/13 15:29, thescullster wrote:
Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Unless in a hermetically sealed room, not at all. Does a heat source like a radiator change atmospheric pressure? Nope, But it can affect instruments in any case. But normally yoi calibarte once its oin its final location. Can I mount this on a wall above a radiator and expect it to work? yup From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? no its because the air pressure only moves slowly over days. Thanks Phil -- Ineptocracy (in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers. |
OT Barometer Location
On 26/06/13 17:12, Nick wrote:
"thescullster" wrote in message ... Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Location will not affect the baro, but it will affect the thermometer and possibly the wood. Don't know much of aneroids, prefer mercury. As regards movement of the needle. Set baro in desired position. Align the cursor with the hand. Repeat at 10am every day of course. Note the movement of the hand over a 24hr period. If the swing is 30 deg or more- Sun hat if up, raincoat, hat & wellies if it's down. Do you have a dinghy? Just keep an eye on it for a few days. I suspect most aneroid baros would not be repairable. TBH, they're not worth it. I did repair one I got at auction. REMARKABLY similar to that. It turned out there was a little teeny bicycle chain inside it that connected the capsule to the pointer shaft and that was all rusted up. Some easing oil and brushing with paraffin got it all cleaned up and free, then it got some very light machine oil. I think the seller of the item you show is utterly and completely off trolley. Delete the first number, divide the remainder by two and you might be in the real world. hth Nick. i think I had to bid against another nutter like me and i paid 85 quid. I like **** like that. -- Ineptocracy (in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers. |
OT Barometer Location
On 26/06/13 17:21, newshound wrote:
On 26/06/2013 15:29, thescullster wrote: Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Thanks Phil The heat source doesn't change atmospheric pressure, but the pressure reading will cycle a little as the instrument temperature changes, something like 3% for a 10 degree C variation. If the needle isn't moving much it's likely that the bellows has a leak, or there is a problem in the (relatively fragile) linkage between the bellows and the needle. The latter. It will almost certainly be what mine is. a teensy sprocket chain round a drum, very prone to rusting if left in a loft or a shed. I've never had the aneroid capsule itself go ..on several I have owned over the years. the final shaft bearing may be seized too. gentle working of the mechanism and light oil gets it all back. If a smart tap on the face doesn't cause the needle to jump, its seized in some way. If it jumps, but doesn't move with the weather, the capsule has gone. -- Ineptocracy (in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers. |
OT Barometer Location
thescullster wrote:
Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? It needs to be in a hallway, near an elephant's foot full of walking sticks and umbrellas, and you need to tap it with your pipe every day before you go outside. |
OT Barometer Location
thescullster wrote:
Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Thanks Phil Are you quite sure it's aneroid? You do get mercury gauges (with a "clock" display) and you need to a bit careful handling those. Tim |
OT Barometer Location
On 26/06/2013 15:29, thescullster wrote:
Hi all I have come by an old barometer - something like the item shown here http://www.hemswell-antiques.com/ant...ter-33028.html (although not quite of the quality). Now I know that these devices measure atmospheric pressure, but I am not clear on how much this will be affected by the instrument location. Does a heat source like a radiator change atmospheric pressure? Can I mount this on a wall above a radiator and expect it to work? From my memory of the barometer, the needle doesn't appear to move much in operation. Is this because it was previously in a centrally heated house, or is there likely to be something wrong here? Thanks Phil Many thanks to all respondents - I'll give it a tap with my pipe and see what the needle does! Looks good held up above the hall rad, but I understand the concerns over the wood. Phil |
OT Barometer Location
On Wed, 26 Jun 2013 16:21:55 +0100, "Brian Gaff"
wrote: I see we are all supposed to be using Hecto Pascals now instead of Millibarrs etc. **** the Frogs - that's a slap in the face for the Barrs. |
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