TRANSACTIONS OF THE SECTIONS. 



219 



Description of a New System of House Ventilation. By J. D. Moekison. 



The maiu features of this novel system of warming- and ventilating, consist in 

 so circulating pure fi-esh air (tlirough a warming chamber) into the room, and of foul 

 ail" (through the tire) into tire chimney, that all local currents are resolved into one, 

 which, describing an unbroken circuit, forms an upper warmer current from the 

 fire to the opposite wall, and an under colder current from the wall back again to 

 the lire, when, after supporting combustion, the products escape up the chimney. 

 The vacuum thus produced by the warmer current through the chinniey creates 

 the now colder current from the atmosphere, which, passing tlirough the heating- 

 chamber, supports the respiration of any number of men. 



On an Imjjroved Vertical Annular Hi<jh-pressure Steam-boiler. 

 By William Smith, C.E., F.C.S., F.G.S. 



This paper described an improved vertical high-pressure annular steam-boiler, 

 recently invented by Messrs. AUibon and Manbre, and manufactured l)v JNIessrs. 

 Allibon, Noj'es and Co., of the Rosherviile Iron-works, Northfleet, as it fulfils to 

 a remarkable extent the conditions indispensable in a steam-generator, and that, too, 

 with an extreme simplicity of construction. Now the boiler stands by itself in this 

 latter respect. The body of the boiler and the fire-box are constructed separately 

 as distinct parts, the water and flue-spaces being disposed annularly. The outer 

 part consists of the external skin or shell of the boiler, and a concentric inner 

 cylinder is rivetted thereto near the bottom, a wrought-iron ring being interposed 

 to keep the proper distance apart. This inner cylinder is also firmly stayed to the 

 shell by screwed stays placed at suitable distances apart. 



To the top of this inner cylinder a tube-plate is rivetted, which is also connected 

 to a central pendant annular water-space, descending to within a short distance of 

 the furnace-bars. 



Thus the fire-box proper consists of two rings forming an aimular water-space 

 round the furnace, the inner ring being made slightly conical to give a better heat- 

 ing-surface, and at the same time permit the steam to get away freely. The top of 

 this fire-box is connected to the tuoe-plate by a series of short lap-welded tapered 

 tubes, screwed at both ends. 



In the boilers first constructed on the ^Vllibon and Manbre system, the central 

 pendant portion was merely a receiver, pocket, or " pot," but in the boilers now 

 constructed by them an important modification has been introduced to this portion 

 of the boiler. The central portion forms part of the fire-box, to which it is con- 

 nected by the short horizontal tubes or Hue-passages shown at the top of the cen- 

 tral pendant portion. The products of combustion, on reaching the top of the fire- 

 box, are deflected by the upper tube-plate, and descend between the outer ring of 

 the fire-box and the inner cylinder or body of the boiler, until they arrive at the 

 bottom, where they pass into an annular flue surrounding the base of the boiler, 

 and from thence by an oblong flue or uptake to the chimney. 



The flue-passages are made sufficiently large to allow of their being cleaned easily, 

 and any repairs ett'ected. 



The annular flue sm'rounding the base of the boiler may also be converted into 

 a feed water-heater by jacketting or surrounding it with a water-space. 



The feed is pumped in by a circulating pump ; a check-valve and a reUef-valve 

 being pro^vided to prevent any excess of pressure. 



This system possesses all the well-known advantages of vertical independent 

 boilers, rendering unnecessary the hea^-y item of expenditure for the setting of 

 Cornish and other enclosed boilers, whilst it allows of free inspection, and the con- 

 sequent ready detection of leakage or other defects, and thus tends materially to 

 diminish the risk of explosion. 



Amongst some of the leading features of this boiler may be included the thorough 

 circulation of water which is insured, the large extent of effective heating-surface, 

 the rapid boiling oft" of large vohmies of steam, the thorough utilization of the pro- 

 ducts of combustion, simplicity in construction of the several parts, and great 

 strength of the whole as a steam-generator. 



