Platinum Metals Rev., 1970, 14, (2), 46
Rhodium-Platinum Thermocouples for Incinerator Control
The disposal of the ever-increasing volumes of household and trade refuse is presenting local authorities with a considerable problem. Incineration under controlled conditions is a practical solution being adopted by a number of authorities (1). At Middleton, Lancashire, Motherwell Bridge Tacol Ltd has installed for the local Corporation the first incinerator of an advanced design which can handle 60 tons of refuse per day at the rate of 8 tons per hour.
Incoming refuse is fed from a hopper to the incinerator grate, which consists of six rollers arranged in descending order at an angle of 30°. Each roller is made up into a unit 8 feet wide and 5 feet in diameter from interlocking grate bar segments between which gaps allow fan-forced combustion air to pass. The rollers slowly rotate and refuse is dried and ignited as it falls from one roller to the next until it finally leaves the grate as fine ash and clinker. Incinerator temperature is monitored and maintained at 900°C by a Petite Q12 indicator/controller fed with signals from a duplex platinum : 10 per cent rhodium-platinum thermocouple in the roof of the combustion chamber.
After leaving the last roller the ash and clinker is quenched in a submerged belt conveyor and is passed on for disposal. The hot flue gases pass via a dust extractor to a 150 foot chimney. A second duplex platinum : 10 per cent rhodium-platinum thermocouple monitors the flue gas temperature at the entrance to the dust extractor and passes a signal to control the introduction of cooling air to the gas stream.
- 1Instrum. Prac. 1969, 23, (10), 706 – 707