DUPLICATE RETURN-TUBULAR ARRANGEMENT.

109

space, of course, being alloted to cleanse andrenew tbe tubes. This is obvious on remem-bering that the length of the tubes is aboutequal to that of the fire grate; and that thewidth of the smoke box is added to the longi-tudinal space required. Also the space re-quired for stoking can be said to be analogous

Fig ,

ternally, the fire boxes could be centrally situ-ated,”—the acquirement of this, affecting theposition of the longitudinal flue peculiar to thedisposition of detail. It will be remembered,also, that the side flue produces a return actionof the flame from the aft smoke box. Now,it is in allusion to this latter acquisition that

16 .

ooo

oooooooooooooooo o o

OOP

ooo

ooo

ooo

ooo

I I I

ooo

I ) I

ooo

ooo

ooo

OOO

ooo

ooo

^ rrnrHr-r-r-rtj :

te n

11° M° 11° 11° II"

r—ft—"I

brfcri

r-ffi-AI

'

i—m—°ll °ll

ji.

BUKGIl’a DUPLICATE RETURN-TUBE MARINE LOW BOILER.

to that for cleansing the tubes, as far as theduties of the operator are concerned.—Theseremarks apply especially to boilers arranged^vith fire boxes at each end of the shell, or foreand aft.

It is stated, in allusion to the arrangementprior to this, that, “ by a slight alteration in-

the arrangement at present under noticepertains.

The above illustrations, fig. 16, representthe plan and elevation of our low boiler, witha duplicate arrangement throughout. Thefire boxes fore and aft are centrally placed inthe shell. The combustion chamber is common