452 SEC. 12. APPLIED MECHANICS. 



1935. Wood Model of Disc Engine. (Taylor and Davies' 

 Patent, 1836.) Bennet Woodcraft, FM.S. 



1939. Models (2) of Rotary Engines. 



Bennet Woodcraft, F.R.S. 



1931. Rotary Steam Engine. Designed and made by the 



Rev. Patrick Bell. H.M. Commissioners of Patents. 



2136. Stationary Direct-acting Steam Engine (model). 

 Royal Geological Institute and Mining Acad&my (Director ^ 



Prof. Hauchecorne\ Berlin. 



The cylinder and valve chest are opened so as to show the various parts. 

 The eccentric is adjustable with reference to throw and lead; accordingly 

 the valve rod and valve are changeable. 



This model shows the general arrangement and essential details of a 

 stationary direst-acting engine, and is arranged specially to demonstrate the 

 relative motions and positions of the piston and the slide valve, and the 

 mechanisms connected with them. 



It shows : 



1 . The dead points of the machine ; 



2. The necessary relative positions of eccentric and crank ; 



3. The way in which a steam engine is compelled to move in one direction. 



4. The lead of the valve and the eccentric, and their influence upon the 



steam admission ; 



5. The lap of the valve and its connexion with the angular advance of the 



eccentric and the expansion of the steam ; 



6. The irregularities in steam distribution and in the transmission of 



motion to the fly-wheel, caused by the obliquity of the connecting-rod ; 

 and 



7. The effects upon the steam distribution of an eccentric rod of wrong 



length or an eccentric wrongly adjusted. 



2137. Model of a Direct - acting Cornish Pumping 



Engine, with cataract. 



Royal Geological Institute and Mining Academy (Director, 

 Prof. Hauchecorne\ Berlin. 



This (also with open cylinder) has a cataract of simple construction, and 

 a systematically arranged valve motion. 



The model serves, in the first place, to illustrate the general nature 

 of click-trains used as valve gear, and their application by means 

 of a plug rod and tappets worked from a beam. It also shows in par- 

 ticular the mode of employing a condenser in a single-acting engine, where 

 three valves (admission, exhaust, and equilibrium) are necessary, with their 

 three separate weigh shafts and wipers, clicks, weights, and levers. The com- 

 mencement of the expansion is shown very distinctly by the closing of the 

 inlet valve. The pause at the end of the " indoor " stroke is effected by 

 means of the cataract, which is filled with petroleum ; the action of this 

 mechanism can be very distinctly observed. With a slow motion of the 

 cataract, it can also be easily noticed that the exhaust valve opens a little 

 sooner than the steam valve, in order that a sufficient vacuum may exist on 

 one side of the piston before the steam is admitted on the other. 



The condenser itself is omitted in order to simplify the model and to make 

 the complicated valve gear somewhat more easy to understand. A lever far 



