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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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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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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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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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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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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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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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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. | |||
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Function Principle of the functioning of the siphon. |
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Description It is all made of glass, with a siphon and a normal emery-polished cone to apply on the base of the cup. Because the bottom of the cup is crossed by the long branch of the siphon, the efflux of the water begins when the level overcomes the bend of the siphon and ends when it reaches the end of the short branch. If we take care of making the water in the cup arrive through a tube with its the section smaller than the siphon, the efflux becomes automatic and intermittent. By regulating a cock, we can change the frequency. | |||
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Function Effects of the pressure. |
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Description The container is like a bottle with a base. It has a metallic escutcheon, to which a brass tube with key is applied. The tube reaches the bottom of the container and a compression pump with a valve. This is used also as a safety valve. With the pump we compress the air over the water in the bottle and we close the key. When we open the key, we have a jet that is proportional to the strength of the pressure of the air. | |||
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Function To study the effects of the atmospheric pressure. |
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Description This apparatus must be applied to the pneumatic pump. It only needs a simple pressure on the opening of the plate with the intermediary of a rubber top with a hole. When we turn the key, we have a partial vacuum. Then we close it. We introduce the lower part of the cock into the water, and when we open we obtain a violent jet. If the rarefaction is exaggerated, the water could fill the tube-test completely. When the experiment is over, the water is extracted by opening the cock. | |||
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Function Measure of the mass of air held in a globe. |
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Description The glass globe has a capacity of two litres and it is provided with an escutcheon with a screw lid and cock. It is applied onto the pneumatic pump with a rubber tube or with a perforated rubber stopper placed over the opening of the plate. After the vacuum has been completed, we hang the globe from the hydrostatic balance and we establish the equilibrium. By then opening the key the balance goes towards the side of the globe. The weights that we must add to the opposite side, give us the weight of the air extracted from the pump. | |||
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School Spano |
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Function To study the effects of the atmospheric pressure. | |||
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Description It is a strong tube-test with an emery-polished basis, to apply onto the plate of the pneumatic pump. The bottom is crossed by a glass tube curved at the bottom, so that the drops of mercury coming from above cannot enter the pump. To the neck of the tube-test on emery-polished cylindrical funnel is adapted. The 3-centimetre diameter bottom of the funnel is fixed to a wood disk. To obtain a good result, it is convenient to oil the basis and the neck. When the pump works, the mercury placed in the upper funnel, crosses the wooden bottom like a tiny rain and it assembles in the bottom of the tube-test. | |||
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Function Effects of the atmospheric pressure. |
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Description The instrument is formed by two brass hemispheres each one connected by a short cylinder to a handle. One of the cylinders is hollow and presents a connection with key to connect it to the pneumatic pump. Because of the great surface of the instrument a great vacuum is not necessary. | |||
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Function Effects of the atmospheric pressure. |
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Description To a cylinder with a solid wall we apply a disk of paper or a rubber sheet. By winding it under the edge of the cylinder. If the paper is homogeneous and very dry, a paper disk corresponding to the diameter of the glass will detach itself after the first blows of the piston. The rubber sheet expands along the internal wall of the cylinder and on the plate, also closing the hole of communication. | |||
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Function Used in the study of osmosis. |
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Description A little film of gypsum is put in the place of a porous vessel. A clutch bar is linked to the lateral manometer, so that the exit of the air above the mercury column is free. The shift of the bar causes the contact. The basis of the instrument is in cast iron. To avoid sparks of transient current it is advised to use a small tension (2 volt). | |||
