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School Castelvì |
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Function To create very low pressures. | |||
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Description Pneumatic pump with a hand piston. Made in metal. It is used for low rarefactions. | |||
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School Spano |
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Function To create very low pressures. | |||
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Description Very strong model, on a solid base, with a hand or a motor flywheel with flat belt. The platform is covered with a solid plate of emery-polished glass. All the communications are made with a copper or brass tube and the keys have a deep rut for the oil lock. In normal conditions it reaches the pressure of a fifth of millimetre. With the interposition of a carbon oxide drier or with carefully purified oil the rarefaction goes beyond this limit. | |||
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School University |
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Function Sucking and forcing pump. | |||
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Description The pump is made of brass and stands on a heavy basis. The two valves placed on the suction and compression pipe fittings have reversed functions. The capacities of the pump are limited. | |||
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School University |
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Function Creating big vacuums. | |||
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Description We must create a preliminary vacuum with normal pumps. It is formed by a boiler to generate vapour currents (oil) that come out very fast through some diffusers. During its motion the vapour drags the molecules towards the efflux mouth. The steam is cooled and it condenses on the walls from which it goes back to the boiler. | |||
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School Spano |
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Function Instrument to measure the pressure. | |||
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Description The container of mercury, welded to the manometric tube, is provided with a connection with a turning screw. All the parts are fixed on a little oak wood table and the scale in mm is sliding, so that for any reading we can move the zero of the scale to the level of the mercury in the container. As a manometer it is used for pressures up to 1 atmosphere. By joining the lateral tube with the pneumatic machine or with the container where the rarefaction is produced, the apparatus works as a vacuum gage. | |||
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School Spano |
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Function Instrument to measure the pressure. | |||
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Description It is a tube for manometer, but with a very thin wall, so that it can be used as a manometric tube or as a vacuum gage. For this the index, controlled by a simple system of levers, stays in the medium of the scale in the normal position. The apparatus can be applied as vacuum gage to the pneumatic machines. This model is very useful to explain the operation of Bourdon’s barometer, of the vacuum gage and of the metallic barometer. | |||
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School Spano |
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Function To verify the law of Boyle - Mariotte in the isothermal process for pressures greater than 1 atm. | |||
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Description It is right for pressures until 2 atmospheres. The model is very simple and solid. The two branches of the glass tube are joined in the bottom with a connection of iron provided with a lateral key for the unloading. It can easily move the mercury to the first notch of the scale of the volumes. The branch that must hold the mass of air is provided with a glass key, so that it is easy to move the mercury to the same level in the two branches and to shut the air at the external pressure. The scale of the volumes is cm 24 and shows clearly the notches that correspond to the volumes 1, 2/3, ½. The scale of the pressure is sliding and it is possible to note from afar the notches corresponding to the pressures 1, 3/32, 2. The shift of the scale, uncommon in apparatus of this type, avoids the disadvantage of having to substrate the height of the mercury in the shorter branch from the height of the mercury in the longer one at the moment of each experiment. It is recommended to oil the glass key for a perfect hermetic seal. | |||
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School Spano |
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Function To verify the law of Boyle - Mariotte in the isothermal process for pressure lesser than 1 atm. | |||
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Description A vertical 3 cm diameter tube is fixed onto a cast iron basis and ends above with a glass vessel at the top. The ensemble forms a very deep vessel that is filled with mercury. In this vessel we introduce a 80 cm long barometric tube with cock, driven and supported by a fork with variable height. | |||
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School Spano |
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Function Instrument for the measure of the atmospheric pressure. | |||
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Description Great basin, a 10 mm barometric pipe, a vernier reading up to 1/20 thermometer. It is mounted on a walnut table, to which are applied a thermometer, a mirror to facilitate the readings, a lower ring with three screws for blocking the basin and a terminal eyelet to hang the instrument. | |||
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School Spano (1), Castelvì (2) |
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Function Instrument for the measure of the pressure. | |||
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Description Under a bell jar with a perfect hermetic seal a common mechanism of the aneroid with a metallic lung is mounted. Thanks to a sphere we can produce in this space the positive and negative variations of pressure necessary to show, with wide excursions of the index, the functioning of the aneroid barometer (without liquid). With the cock open, the model works as a normal metallic barometer. | |||
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School Spano |
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Function Instrument for the measure of the pressure. | |||
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Description Manometer mercury with a base and a nickered brass support. There is also a celluloid scale in mm. The mercury moves from the closed branch when the pressure reached in the container equals the height of the liquid column, measured from the free surface in the open branch. An emery-polished connection allows to connect the gauge with the container where the vacuum is made without the instrument. | |||
