vacuum pump

3 definitions found

vacuum pump - Collaborative International Dictionary of English v.0.48 :

  Pulsometer \Pul*som"e*ter\, n. [Pulse + -meter.]
     [1913 Webster]
     1. A device, with valves, for raising water by steam, partly
        by atmospheric pressure, and partly by the direct action
        of the steam on the water, without the intervention of a
        piston; -- also called vacuum pump.
        [1913 Webster]
  
     2. A pulsimeter.
        [1913 Webster]

  Vacuum \Vac"u*um\ (v[a^]k"[-u]*[u^]m), n.; pl. E. Vacuums
     (v[a^]k"[-u]*[u^]mz), L. Vacua (v[a^]k"[-u]*[.a]). [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]
        [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) a glass tube provided with platinum electrodes and
            exhausted, for the passage of the electrical
            discharge; a Geissler tube.
        (a) any tube used in electronic devices, containing a
            vacuum and used to control the flow of electrons in a
            circuit, as a vacuum diode, triode, tetrode, or
            pentode.
  
     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]

vacuum pump - WordNet (r) 2.1 (2005) :

  vacuum pump
      n 1: a pump that moves air in or out of something [syn: air pump
           , vacuum pump]