File:Practical radiography - a handbook for physicians, surgeons, and other users of X-rays (1901) (14571315827).jpg

Identifier: practicalradiogr00isen (find matches)
Title: Practical radiography : a handbook for physicians, surgeons, and other users of X-rays
Year: 1901 (1900s)
Authors: Isenthal, A. W Ward, H. Snowden (Henry Snowden), 1865-1911
Subjects: Radiography X-rays X-rays Radiography X-Rays
Publisher: London : Published for The Photogram, Ltd. by Dawbarn and Ward, Ltd.
Contributing Library: Francis A. Countway Library of Medicine
Digitizing Sponsor: Open Knowledge Commons and Harvard Medical School

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ig. 27. surface is replaced by solid metallic contacts. The jet ismaintained either by centrifugal force or by mechanicalmeans, or by gravitation, but in every instance the exis-tence of the jet is dependent on the rotation or movementof the break, so that there exists no jet, and consequentlyno contact, until the break is working, whether the circuitthrough the primary of the coil be closed or open. A reference to the individual types will make this quite clear. The earliest form of these jet interrupters consists of asuction tube bent at right angles, rapidly rotating round 68 Practical Radiography its vertical axis and with the lower end permanentlydipping in a quantity of mercury. The mercury rises bycentrifugal force, and is forced out of the horizontal branchof the tube in the shape of a fine stream, impinging againstthe inner surface of a contact cylinder. If we connectthe mercury with one end of the coil primary and thecontact cylinder with the other terminal, and if, further,
Text Appearing After Image:
Fie. 28. the contact cylinder is fitted with sectors of insulatingmaterial, then, on rotating the bent tube, we obtain aseries of interruptions, the frequency of which is pro-portional to the number of contacts and the revolutions ofthe spindle. Eeplacing the contact pieces by others ofvarious shapes and widths we have it in our power to varyboth the number and relative duration of the contactperiods. After establishing contact, the mercury falls tothe bottom of the containing vessel in order to be againsucked up, and so on. Induction Coils and Interrupters 69 A vastly more convenient modification of a jet break isrepresented by a construction of Dr. Max Levy (Figs. 29 and30). Its novel features are a stationary mercury jet andthe method adopted for adjusting the duration of contact.The stationary jet is obtained by a simple displacementmotion, such as a couple of geared pinions rotating in aclosely-fitting case. By this means a jet is produced atvery low speeds to begin with, and as

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