Temperature Measurement by Exhaust Thermocouple in Engines

Exhaust Thermocouple Sensors are a key element of modern engine management. Measuring the temperature of exhaust gas can provide an important input into system algorithms to improve efficiency, reduce pollutants and extend engine life.

Exhaust Gas sensors are usually thermocouples due to the very high temperatures involved. Often 800°C or more can be achieved. Thermocouple type K is the most common although type J is also found in lower performance engines.

Exhaust Thermocouple Design

The Primary requirement of an Exhaust Thermocouple is to be robust enough to survive a high vibration environment. After that it must be small enough to respond quickly and not disrupt gas flows.… Read more

POX Temperature Sensor for Chemical Plants

Peak Sensors supplies temperature sensors to many specialised applications. POX, Partial Oxidation is a chemical plant process which uses fuel / air mixture to partially oxidise the gases into other useful products. Carbon Monoxide is the common product. The POX temperature sensor requires some novel design detail to survive the plant and to be safe should failure occur.

POX Process

This process occurs at temperatures around 1200 deg C. It is a very aggressive environment for temperature sensors. Heat, Pressure, Oxygen and Combustion products are present. A number of Probes are typically situated almost within the insulation to give them some protection. As insulation deteriates over the plant life the probes get an even tougher life.… Read more

Compost Temperature Sensor Design

Commercial Composting demands good temperature measurement and control. Elevated temperatures are required for throughput management and legal compliance. Compost temperature sensors are required for process management.

Compost Process

Temperatures of around 65 deg C are needed to optimise micro organism activity, accelerate organic matter breakdown, destroy pathogens and eliminate weed seeds. Low temperatures will allow anaerobic rotting to occur.

Throughput, process control and material handling are improved by using in vessel composting systems. Temperature sensors are inserted at strategic positions.

Compost Temperature Sensor design

The sensors have unique design features for this application. The temperature sensors get a rough tough life. Nothing seems to be delicate when making compost so probes must be very robust.… Read more

Glass Furnace Temperature Sensors

Glass furnaces have significant temperature control issues. Glass furnace temperature can range from around 1100 °C to 1600 °C. Thermocouples need to be made of Precious metals to survive this.

Melter Furnace

During the initial melting of glass cullet, sufficient melt temperature is required to achieve the glass condition required for processing, however excess heating uses extra fuel, shortens plant life and can affect the glass batch properties in an undesirable way.

Melters have temperature sensors in Walls, Roof (Crown) and Bottom. Sensors are often tagged: Melter Bottom, Sump Bottom, Riser sidewall, Channel bottom, Crown, Melter Side wall and so on.… Read more

TC Temperature Sensors

TC is a common abbreviation for Thermocouple. A TC is made from two different wires joined in a loop. When the temperatures of the joins (Hot Junction and Cold Junction) are different a very small current flows. It the cold junction is split, and a voltmeter is placed there, it detects an EMF. When the dissimilar wire alloys are defined alloy pairs, the EMF can be used to determine the temperature difference, and thus the temperature of the hot junction.

Common TC Pairs

K Type is the most common. (NiCr v NiMgAlSi) This TC operates from -200 to + 1300°C.… Read more

Aerospace Heat Treatment Thermocouples to AMS 2750D

Aerospace Heat Treatment applications require AMS 2750D thermocouples. The key point of this standard, for sensor makers, demands that Thermocouples are calibrated by approved means and shown to be within defined limits. Individual sensors or batches of Thermocouple material can be tested. The maximum acceptable error depends on sensor use. There are strict limits on the number of uses before recalibration or replacement is required.

Peak Sensors often supplies Mineral Insulated Thermocouples, Rare Metal Thermocouples or Thermocouple wire batch certified. Thermocouple type R, type S and type N are the most common aerospace sensors.

Cost Reduction for AMS 2750D

To minimise Mineral Insulated Thermocouple sensor costs, Peak Sensors will have batches of wire calibrated and then from it, build sensors according to a customers requirement.… Read more

Tri Level Thermocouple Sensors for Glass Furnaces

Tri Level thermocouples are used in a glass forehearth. They monitor the condition of the glass before forming into shapes. The sensors provide feedback to heaters allowing temperature control across the glass channel. Tri Level sensors have three measuring points at defined positions along the sensor length. Glass depths are often around 150mm. Three measuring points, say 25, 75, and 125mm from the bottom give the temperature profile of the glass flow. A thimble 200mm is normally adequate.

Tri Level thermocouples are often in banks of 4 pieces. One upstream, central in the forehearth channel, detecting the approaching glass flow temperatures, then 3 in a line across the glass channel as the product nears the bowl.… Read more

Temperature Sensor Selection for Design Engineers: Technology Review

Temperature is probably the most commonly measured physical parameter. Appropriate temperature sensor selection is essential. Designers have to decide on the best technology to employ considering the design brief. The sensor design comprises the employed sensor technology and the protection of the sensor from the process. This article covers the choice of temperature sensor selection.

Temperature Sensor Selection Technology Review

Each common technology has attributes:

	Thermocouple	Thermistor	Resistance Thermometer	Digital Sensor	Infrared
Temp Range °C	-270 to +2000	-90 to + 130	-200 to + 600	-10 to +85	-50 to 3000
Cost	Medium to Very High	Low	Low	Medium	High
Instrumentation	Readily Available or designed on a board	Designed in Circuit board	Readily Available or designed on a board	Designed in Circuit board	IR Supplier
Linearity	Non Linear	NTC’s are Non Linear	Linear	Linear
Signal	mV	K Ohms	100 / 1000 Ohms	Digital
Accuracy	Fair	Fair	Good	Excellent	Fair
Extension Cable	2 leads made of TC Extension Cable	2 leads	2, 3 or 4 leads	3 Leads
Notes	Cold Junction Compensation		Lead resistance can be significant		Non Contact Optical Sensor.

The Temperature Sensor Specialists

Constantly improving temperature measurement.

Category Archives: TC