Lamp Pump. 
137 
off communication through the port (c), the valve port (l) in 
the control valve, and the pipe (d). The piston is thus in 
equilibrium and commences to descend, partly by its own 
weight, and partly by the vacuum on the under side of the 
pump plunger, which also acts as the piston of the air pump. 
During the down stroke the steam that was below the main 
piston is displaced and passes through the pipe (d) and the 
port (C) to the upper end of the cylinder at its original volume. 
This still maintains the control valve (a) at the top of its 
stroke until the portway (l) in the main piston rod opens 
a port in the cylinder cover (not shown in the drawing) which 
communicates with the condenser through the port (m) and 
the pipe (k). The result is that there is again a vacuum on 
the top side of the piston which, through the pipe (b) again 
draws the control valve (A) to the position shown on the 
drawing, and steam is again admitted for the next stroke. 
The action of the main pump and the air pump are clearly 
shown on the drawing ; the small free piston (G) drives out 
the products of condensation through the check valve (h). It 
is controlled by the action of the water in the pump barrel. 
A trial was made of the two pumps exhibited, but owing to 
slight mechanical defects of construction, the results were not 
as satisfactory as might have been expected ; these will most 
probably be eliminated in future pumps. There is no doubt 
a demand for a handy pump for small supplies, and the Lamp 
Pump would appear to be likely to meet this demand. 
The best thanks of my colleague, Mr. James Younger, and 
myself are due to the Stewards of Implements, Mr. R. M. 
Greaves and Mr. Claude M. S. Pilkington, and to the Society’s 
Consulting Engineer, Mr. F. S. Courtney, for the valuable 
assistance they afforded us. 
Thomas Stirton. 
Rendlesham Estates Office, 
Woodbridge, Suffolk. 
