_L_, Expansion chamber;
_M_, Escape pipe;
_N_, Feed pipe;
_O_, Agitator for residuum;
_P_, Residuum valve;
_Q_, Water level]

[Illustration: Figure 12.--Feed Mechanism of Pressure Generator]

Should the pressure rise much above the blow-off point, the safety
controlling diaphragm valve will operate and throw the safety clutch in
interference and thus stop the motor. This interference clutch will then
have to be returned to its former position before the motor will operate,
but cannot be replaced before the pressure has been reduced below the
blow-off point.

The parts of the feed mechanism illustrated in Figure 12 are as follows:
_A_, motor drum for weight cable. _B_, carbide filling plugs.
_C_, chains for connecting safety locking lever of motor to pins on
the top of the carbide plugs. _D_, interference clutch of motor.
_E_, lever on feed controlling diaphragm valve. _F_, lever of
interference controlling diaphragm valve that operates interference clutch.
_G_, feed controlling diaphragm valve. _H_, diaphragm valve
controlling operation of interference clutch. _I_, interference pin
to engage emergency clutch. _J_, main shaft driving carbide feeding
disc. _Y_, safety locking lever.

_Recharging Generator._--Turn the agitator handle rapidly for several
revolutions, and then open the residuum valve, having five or six pounds
gas pressure on the machine. If the carbide charge has been exhausted and