27.03.2013 Views

Cork insulation; a complete illustrated textbook on cork insulation ...

Cork insulation; a complete illustrated textbook on cork insulation ...

Cork insulation; a complete illustrated textbook on cork insulation ...

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

120 CORK INSULATION<br />

the areas and the areas being held in place by four pieces<br />

of Advance wire soldered to the copper plates.<br />

By the use of a galvanometer, the inner area and the<br />

outer guard ring are kept at the same temperature, this c<strong>on</strong>diti<strong>on</strong><br />

being indicated by a zero reading, and under which<br />

c<strong>on</strong>diti<strong>on</strong> it is assumed that no heat flows from the 8x8 inch<br />

I<br />

MAM<br />

/ / / ^ o^/<br />

- EDGE INSULATION<br />

TBsrs/ifiPLes<br />

FIG. 44.—DIAGRAMMATIC SKETCH OF APPARATUS FOR THE PLATE<br />

METHOD OF MEASURING THE THERMAL CONDUCTIVITY OF<br />

MATERIALS.<br />

inner porti<strong>on</strong> of the test area to the outer porti<strong>on</strong> of the<br />

test area or guard ring.<br />

Direct current from a generating set is supplied to the<br />

main heating grid and also to the auxiliary guard ring cir-<br />

cuit; and to prevent any variati<strong>on</strong> in current due to voltage<br />

fluctuati<strong>on</strong>, a ballast tube, similar to that used with radio sets,<br />

is placed in the main line and automatically keeps the current<br />

c<strong>on</strong>stant to the main heating grid.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!