Volume 1

Radiography and radio-therapeutics / by Robert Knox.

  • Knox, Robert, 1868-1928
Date:
1919-
Catalogue details

Licence: In copyright

Credit: Radiography and radio-therapeutics / by Robert Knox. Source: Wellcome Collection.

    58/544 (page 24)
    deal depends upon the construction of the coil and the interrupter, and the accuracy with which they are adjusted to one another. Other factors may also influence the degree of inverse current produced. The Interrupter This important part of an X-ray outfit requires a lengthy consideration, and it will well repay the beginner to familiarise himself thoroughly with this part of his installation. He must know its construction, how to regulate it, and above all how to clean it when necessary. The interrupter serves the purpose of closing and opening the primary circuit. It should keep the primary current closed long enough to allow the iron core to reach the maximum magnetisation. The sharper the opening of the primary circuit, the higher will be the tension of the secondary current— the opening induction cur¬ rent—and the greater there¬ fore is the discharge. For practical purposes there are two types of in¬ terrupters which require description. These are : (a) The Mercury Inter¬ rupter. (ib) The Electrolytic Interrupter. Of the former there are many varieties, but it will suffice to mention a few and give a short description of each before proceeding to the electrolytic type. The mer¬ cury interrupters may be Fig. 1].—Diagram to illustrate construction of a centrifugal classified ill three groups ! mercury interrupter. (Siemens.) (1) Dipper, Mackenzie r, Funnel for di-electric. -r\ • t , V, Safety valve. Davidson type. u, Gas tap. e, Containing vessel. 9, 7>i, Motor. c1 and c3, Contacts. d1 and cl1, Mercury jets. q, Mercury. s, Adjustable contact. Closing valve. (2) Rotary, Cavendish. (3) Jet, Dreadnought, Instanta, and others. Probably the best all-round interrupter of the centrifugal mercury type is that now known as the Cavendish, but this has one objectionable feature, viz. the trouble of cleaning it. The undoubted advantage which other forms of mercury interrupters possess over it is the ease with which they may be cleaned, and owing to the fact that gas is used in many as the di¬ electric instead of paraffin they require cleaning less frequently, and, further, the mercury never becomes emulsified. Practically every maker manu-