| 释义 |
pulsator|pʌlˈseɪtə(r), ˈpʌlsətə(r)|
[agent-n. in L. form from pulsāre: see pulsate and -or.]
1. One who or that which knocks or strikes: see quots.; in quot. 1753 the Death-watch. rare.
1656Blount Glossogr., Pulsator, one that knocks or strikes. 1730–6Bailey (folio), Pulsa′tor, the plaintiff or actor. 1753Chambers Cycl. Supp., Pulsator, a name given by some writers to that species of beetle, commonly known among us by the name of the death-watch. 1755Johnson, Pulsa′tor, a striker, a beater. 1836E. Howard R. Reefer xx, The pulsator, with pointed toe.., would make a progress in a direct line.
2. A machine, working on the principle of the jigger, for separating diamonds from the earth in which they are found.
1890Pall Mall G. 13 Feb. 2/1 The residue of divers stones of divers sorts and sizes is then jogged about with more water in the ‘pulsator’... The machine is a huge framework of graduated sieves and runlets. 1901Ibid. 1 July 8/2 The finer material is graded by the screens of the trommel, and passes direct to the four compartments of a pulsator or jigger of the type used at Kimberley.
3. = pulsometer 2.
1884Knight Dict. Mech. Suppl., Pulsator, a name for the Pulsometer.
4. Agric. A device on a milking machine which releases the suction on the teat intermittently so as to simulate the sucking action of a calf.
1907Jrnl. R. Agric. Soc. LXVIII. 133 By another flexible connection the pail communicates with a vacuum pipe, and an air exhaust, by which the pulsators are actuated. 1931J. B. Davidson Agric. Machinery xxxii. 339 The pulsator is an air valve so constructed as to alternate suction and release. 1950N.Z. Jrnl. Agric. LXXX. 568/2 Efficient milking is not possible with leaking pulsators. 1970R. Jeffries Dead Man's Bluff i. 12 The milk began to spurt into the glass jars... The rhythmic clicking of the pulsator, working off the vacuum line, gave him a conscious feeling of well-being. |