Vacuum valve

Vacuum Vac"u*um, n.; pl. E. {Vacuums}, L. {Vacua}. [L., fr. vacuus empty. See {Vacuous}.] 1. (Physics) A space entirely devoid of matter (called also, by way of distinction, absolute vacuum); hence, in a more general sense, a space, as the interior of a closed vessel, which has been exhausted to a high or the highest degree by an air pump or other artificial means; as, water boils at a reduced temperature in a vacuum. [1913 Webster]

2. The condition of rarefaction, or reduction of pressure below that of the atmosphere, in a vessel, as the condenser of a steam engine, which is nearly exhausted of air or steam, etc.; as, a vacuum of 26 inches of mercury, or 13 pounds per square inch. [1913 Webster]

{Vacuum brake}, a kind of continuous brake operated by exhausting the air from some appliance under each car, and so causing the pressure of the atmosphere to apply the brakes.

{Vacuum pan} (Technol.), a kind of large closed metallic retort used in sugar making for boiling down sirup. It is so connected with an exhausting apparatus that a partial vacuum is formed within. This allows the evaporation and concentration to take place at a lower atmospheric pressure and hence also at a lower temperature, which largely obviates the danger of burning the sugar, and shortens the process.

{Vacuum pump}. Same as {Pulsometer}, 1.

{Vacuum tube} (Phys.), a glass tube provided with platinum electrodes and exhausted, for the passage of the electrical discharge; a Geissler tube.

{Vacuum valve}, a safety valve opening inward to admit air to a vessel in which the pressure is less than that of the atmosphere, in order to prevent collapse.

{Torricellian vacuum}. See under {Torricellian}. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • vacuum valve — n. Brit. VACUUM TUBE * * * …   Universalium

  • vacuum valve — n. Brit. VACUUM TUBE …   English World dictionary

  • vacuum valve — noun 1. : safety valve 1b 2. chiefly Britain : vacuum tube 3. : a vacuum tube rectifier * * * vacuum valve, Especially British. vacuum tube …   Useful english dictionary

  • vacuum valve — vakuuminė lempa statusas T sritis fizika atitikmenys: angl. vacuum lamp; vacuum tube; vacuum valve vok. Vakuumlampe, f; Vakuumröhre, f rus. вакуумная лампа, f pranc. lampe à vide, f; tube à vide, m …   Fizikos terminų žodynas

  • vacuum valve — vakuuminis vožtuvas statusas T sritis radioelektronika atitikmenys: angl. vacuum valve vok. Vakuumventil, n; Vakuumverschluß, m rus. вакуумный вентиль, m; вакуумный затвор, m; вакуумный клапан, m pranc. soupape à vide, f …   Radioelektronikos terminų žodynas

  • vacuum valve — See thermal vacuum valve …   Dictionary of automotive terms

  • thermal vacuum valve — (TVV) A valve with the same function as a thermal vacuum switch. TVS units, which serve to interrupt exhaust gas recirculation when the temperature is too low, are located in the vacuum line between the ECR valve and inlet manifold or carburetor …   Dictionary of automotive terms

  • pressure-vacuum valve — /presh euhr vak yooh euhm, yoohm/ a valve for relieving a sealed tank of any pressure or vacuum exceeding acceptable limits. * * * …   Universalium

  • hot water vacuum valve — A vacuum actuated valve which controls the flow of coolant through the heater core …   Dictionary of automotive terms

  • pressure-vacuum valve — /presh euhr vak yooh euhm, yoohm/ a valve for relieving a sealed tank of any pressure or vacuum exceeding acceptable limits …   Useful english dictionary

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