Everything is coming together. Ready for the first power-up.

It surprising difficult to find valves that are capable of handling low pressures by high temperatures. In order to pyrolyse material we have to prevent air to enter the pyrolysiscell. The pyrolysiscell has to be airtight but during the pyrolysis process volatile gases are formed, hydrogen and carbon based gasses like evaporating fat. In the first phase when we plan to dehydrate the corpse we must remove the water-vapor and bring fresh air in the cell. During the pyrolysis phase the produced gases are led to an afterburner that burns the hydrogen to water and volatile carbon gasses to CO2. All in all we need three valves that operate temperatures up to 500C and under 2 Bar of pressure.

A central heating valve demolished, a steel ball from a ball bearing as flow director and another problem is solved.

New choice for the embedded computer, the A20 from Olimex. The choice for their thermocouple boards made the switch from the Raspberry Pi as control computer easy. Now we have most of the electronics from one supplier.

Olimex

How to measure reliable the amount of electricity that’s being used by the demonstration pyrolysis cell? With a couple of KW infra-red heaters not so simple especially when you want to integrate the measurements in the computerlog of the test. To test the concept I took an old transformer, replaced the old secondary winding by two windings of the 230 volt wire. Curious if I get a good potential difference on the old primary winding. The primary winding is been shorted with a 20 Ohm resistor. And the voltage over the resistor can be converted in a digital value and fed into the control computer.

Care must be taken that the secondary of a current transformer is not disconnected from its load while current is flowing in the primary, as the transformer secondary will attempt to continue driving current across the effectively infinite impedance up to its core saturation voltage. This may produce a high voltage across the open secondary into the range of several kilovolts, causing arcing, compromising operator and equipment safety, or permanently affect the accuracy of the transformer. source wikipedia

The practice is more complicated due to the load so the real RMS need to be calculated. A acs712 chip connected to an Arduino measures every cycle during one second the actual wattage that is being consumed.

TRIAC BLOCK a solid-state relay with I²C interface.

Looking for parts for our demonstration pyrolysis furnace I came across this design. Capable to regulate the 1Kw Elstein infrared heater without much effort. Controllable trough the I²C bus it connects simple to the computer that controls the furnace. Trough the link I contacted the designer and he did have spare assembled PCB’s, a deal was made and a problem solved.