Attractive tabletop instrument.
Hand-blown glass parts in strong borosilicate glass.
Carefully calculated, accurate and aesthetic design.
Fully adjustable for height above sea level.
Fully temperature compensated.
helical measurement tube for easy, precise reading.
Integral thermometer.
Informative guidebook for easy set up and use.
Full warranty and after-sales service.
The TTS007 Compensated Hydrostatic Sympiesometer can be yours, inclusive of carriage for £529.99 plus VAT
Ordering is simple: place your order via email.
You will be sent an invoice which you can settle by cheque or by on-line bank transfer.
Your order will be handled efficiently and with care and despatch will be confirmed to you via email.
Please note that Meteormetrics Instruments are hand-built, tested and calibrated to order and will be supplied within 28 days of your order being received.
The Meteormetrics Hydrometric Sympiesometer combines the accurate application of scientific principle with the aesthetics of elegantly blown glass. The carefully proportioned bulbs, each with its essential purpose combine to provide both functional precision and a visually attractive instrument. The pressure can be read to 1 mB with an accuracy of 2mB - an ample degree of precision for keen observance of the weather.
This instrument is a modification of the hydrometer which is a device designed for measuring the densities of liquids. The standard hydrometer consists of a glass vessel, drawn to a narrow, light stem at the upper end, below which there is a bulb or wider section of tube to provide buoyancy and below that, a counter weight so adjusted that the instrument floats in liquids of a desired density range. The density of the liquid is read off on scale marked on the stem.
The standard hydrometer can be converted to a barometer, in principle by making a hole in the lower part of the bulb, and floating the device in a liquid of known density.
What happens is that a little liquid enters the bulb through the hole and compresses the gas within it slightly. As the atmospheric pressure changes, the degree to which this enclosed gas is compressed alters, and the degree of buoyancy it provide to the instrument varies correspondingly. The result is that the instrument ( which we have called a hydrometric-barometer) floats at a level proportional to the atmospheric pressure.
The design of a working Hydro-barometer has proved an interesting challenge. To get an appropriate response to atmospheric pressure on a suitable scale and, at the same time, provide hydrostatic stability for the instrument, we have found that three bulbs are necessary: a counterweight, a barometric bulb which has an aperture in its wall, and a buoyancy bulb to maintain correct hydrostatic equilibrium. The relative sizes of these bulbs and all the other dimensions of the device can be calculated from a classical mathematical analysis with the aid of some computing.
There is, of course, still the question of temperature compensation. As the temperature increases, gases expand, and as the gas in the barometric bulb of our instrument does so, its buoyancy contribution increases and the instrument rises in the liquid. The rate at which it does so can be calculated from the dimensions of the hydro-barometer. The instrument can be fully compensated by installing a thermometer running down the stem, with the same linear rate as the rise of the instrument with temperature. The atmospheric pressure can be read off as the distance between the end of the thermometer thread and the level of the liquid surface in which the instrument is floating.
The stem of the instrument is suitably calibrated for this purpose with a scale of 1mB per millimetre.
In our knowledgebase you will find a paper which describes the quantitative and theoretical aspects of this instrument as well as details of its manufacture, calibration and performance.