Out of curiosity I bought a Ford Fiesta/Ka/Puma heater control valve on AliExpress for less then 11 euro including shipping to see if it could be used to control the dephlegmator (reflux condenser).
Normally the heating in a car is done by regulating the airflow through the heating core located in the dashboard. To prevent a hot dashboard in the summer the water flow through the heating core is switch off by means of a vacuum operated valve. Sometimes these valves have four water connections, two connected to the coolant system of the engine and two to the heater core. When the heating is switched off the valve act as a bypass preventing the coolant fluid go through the heater core.
In the Ford Fiesta/Ka/Puma this valve is also used to regulate the amount of heat and is solenoid operated. When de-energised all coolant flows through the heater core, when energized the heater core is bypasses and the heater is leak free blocked by means of a seal. From a YouTube movie I got the impression that the valve is a proportional valve, more current through the solenoid means less water through the heater core, however this is not the case. The valve is pulse width modulated with a very low frequency of about 0.3 Hz. For example one second on and two seconds off give 2/3 of the available heat, two seconds on and one second off gives 1/3 of the available heat.
It might be possible to use this valve to control the cooling capacity of a reflux condenser. I remember that have seen a topic on another forum showing the use of switched solenoid valves to regulate the amount of reflux, so this seems to be possible. A Youtube movie from Swede Olson from
http://distillerycontrols.com shows this system using a frequency of about 0.2 Hz. So this valve might be a cost effective solution.
The advantage of using this valve is the use of one solenoid instead of two and the elimination of water hammer, as the coolant flow is not interrupted during switching.
The disadvantage is the short life expectancy according to the amount of Youtube movies that describe how to change this valve. What happens is that the seal diaphragm start leaking causing coolant leakage and/or the valve to seize. In a heater control application the solenoid and the seal diaphragm is always hot, in a cooling application always cold. Maybe this will prolong the life of this valve.
On disassemble I found that one screw was different then the other three, no idea if this is on purpose.
Some details:
Coil resistance ~12 ohm
Coil inductance ~54 mH
Capacitor is 56 pF 3kV
Connecting tube od 16.1 mm with a barb of 18.2 mm
Valve id 11.5 mm
Valve travel about 4 to 5 mm
Manual control could be done with a 555 timer circuit and with an Arduino the sky is probably the limit.
What do you think?
