Page 43 - #50 English

PID
The temperature controller takes an input from a tem-
perature sensor and has an output that is connected to a control
element such as a heater or fan. It is simply a thermometer con-
nected to a computer, this enables the water temperature in the
boiler to be at the exact temperature for the precise brewing. The
water will not be a degree more or less, this standard system is
installed in most of the espresso machines.

Temperature controlled by thermostat (blue) and PID controller
(red)

Heat Exchanger vs. Double or Multi Boiler Espresso machines with double or multi-boilers
In the older days, some believe that it is not possible to The double boiler version has superior control over its
pull the espresso shots and steam or froth milk at the same time. heat exchange counterpart in the temperature control of the
Though, it’s not so true: to be able to extract espresso and steam water in the boiler. This better temperature control allows the
milk at the same time, the machine can either have: baristas to alter the boiler water temperature to match better with
Espresso machines with a heat exchanger or the Multi the coffee being used. However, the sizes of the boiler and the
Boilers. The heat exchanger tube is the larger tube inside the independency of the milk steaming boiler will differ in terms of
single boiler with upside down 'V's. This is the water that is the amount of water in the milk steaming process and the time it
instantly heated to make espresso - coming in cold water is takes for water to heat up.
mixed in with this hot water when the extraction starts. When
not extracting espresso, this same water inside the closed loop
system is heated in the heat exchanger and is pushed through
to the group head which forces the slightly cooler water back
to the boiler for re-heating.

Heat Exchanger Boiler

Boiler Boiler

Single Boiler System Multi Boiler System

Vibration Vs. Rotary pump
Typically, rotary vane pumps are found on espresso ma-
chines with a direct water line connection. The Rotary pump is a
positive-displacement pump that consists of vanes mounted to a
rotor that rotates inside of a cavity. Just as with vibration pumps
with direct water line connections, there are a few exceptions
where a rotary vane pump will be found on a tank/reservoir
espresso machine. There are many advantages of Rotary pump
over the Vibration pump, some major ones are: quieter operation,
and immediate ramp up brew pressure when pump is engaged.
The Rotary Pumps available in most of the La Marzocco are just
awesome for noise in the cafe. Rotary pumps are determined by Rotary Pump
volume output. There are 100 and 200 liters per hour rotary vane
pumps. A rotary vane pump can extract many more espresso per
day than a vibration pump.
Vibrator Pump
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