Chapter 3 Functional descriptions
SMSO-2-02.03- 15.07.03 75
3.4.4 Hot water system (tea) ......... 01.04.2002
......... Serial no. 505123
Product serving:
Requirements:
Notes
A cup of hot water to make tea
Machine in operation, heated up, programmed to automatically serve hot water.
Some processes are shown in simplified form in the following description. See the section entitled
“components” in this chapter for detailed functional descriptions of individual components (e.g. pump
with bypass).
Water metering:
The water quantity can be metered in two ways:
Time controlled by the programming system
By programming the start and stop operation: the hot water starts to flow out when the button is
pressed for the first time, and it stops when pressed a second time. (Timeout: If the button is not
pressed a second time after a certain period of time, the hot water automatically stops running out.
Process
step
Control system (electronic/electrical) Hydraulic system
Product selection
1 The “tea” button is pressed.
The signal from the button panel reaches the unit control system;
the program analyses the command and starts the product
preparation cycle.
Hot water outlet
2 The rotary vane-type pump switches on (relay 3 switches on) and
the hot water outlet valve opens (power transistor connects
through).
Pump produces the pressure in the water system and holds it
constant.
The solenoid valve opens and hot water flows to the hot water
nozzle (tea cup). Cold water flows into the instant heater to top it
up.
Heating the instant heater
3 The temperature in the hot water unit falls; change in resistance in
the temperature sensor sends a “heat” signal to the control sys-
tem.
4 Heating for instant heater switches on (relay 7 connects the load
relay).
The water in the hot water unit is heated.
End of product outlet;
5 The tea cup is filled.
With a programmed quantity of water, after the run-out period
the hot water outlet valve closes and the rotary vane type
pump switches off.
With programmed start-stop operation: The “tea” button is
pressed again; the signal from the button panel reaches the
unit control system; the program analyses the control com-
mand and stops the product from discharging. The hot water
outlet valve closes and the rotary vane type pump switches
off.
The solenoid valve closes and the hot water stops running out; the
rotary vane type pump is stopped and the pressure in the system
falls back to “local pressure”.
End heating
6 Hot water unit heated (to approx. 98
o
C). Resistance change in
the temperature sensor sends a “switch off the heater” signal to
the control system.
7 Switch off the heating (relay 7)
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