Date: September 2006 Sheet No.: 3−36GB

Mechatronic Thermometer for measuring of exhaust gas– A new generation of measuring instruments

The temperature of exhaust gas has to be measured in two different ways: mechanical and electronic. Now Tem-press has combined the two measuring methods in one single instrument, called a mechatronic thermometer. This brings several advantages to the ships. One single unit implies:

- Less spare parts and more rational procedure in the engine room - The same measuring result by installation in pulsating gas - Reduced costs of installation

Developed in co-operation with key customers Tempress has developed the new mechatronic exhaust gas thermometer in close co-operation with customers. They have pointed out that ship owners often – when they receive a ship – complain of the fact that the mechanical and electronic temperature measurements of exhaust gas display different temperatures.

In co-operation with among others MAN B&W and Hyundai Tempress has developed an entirely new standard for measurement of the temperature of the exhaust gas with the new mechatronic exhaust gas thermometer, type A86.

One single instrument – different measurementsThe instrument consists of a mechanical and electronic instrument, which is built together in one single unit. This ensures that the mechanical and electronic temperature measurement is made at the same place in the exhaust gas. This implies a more simple installation with only one instrument per cylinder.

Despite this the measurements will not be identical, as measurement is made on a pulsating gas fl ow. Therefore, it is more appropriate to speak of a mea-surement, which is an average measurement of the temperature in the exhaust gas.

Control of the time constantTo ensure an unambiguous measurement Tempress has developed a converter for the thermocouple, in which the time constant can be controlled. Hereby, the electronic instrument gets the same properties as the mechanical instru-ment and this is the reason that the instrument gives the same readout for the electronic as the mechanical temperature with a converter.

Replaceable spare parts and easy installationTo ensure economical operations with the instru-ment it has been made with replaceable thermo-couple, just as the mechanical instrument also is obtainable as a spare part. The instrument is easy to install, as it only demands a single mount-ing point and with that only one opening into the cylinder. All other things being equal this implies less maintenance.

Being tested at shipyards and engine builders Today, the instrument is in use at MAN B&W, Hyundai, and Dusan and several other engine builders worldwide are testing it.

Nordlandsvej 64 - 66, DK-8240 RisskovTel.: +45 8932 5210, Fax: +45 8932 5213

E-mail: sales@tempress.dk

Tempress is Scandinavia’s largest manufacturer of quality gauges for measuring of temperature, pressure and level. The 70 employees in the company produce over 100,000 units annually, of which by far the majority is produced to customer orders and exported throughout the world.

Mechatronic Thermometer at MAN B&W:For several years MAN B&W has applied the mecha-tronic thermometer for measurement of temperatures on the exhaust manifold. In connection with delivery of plants they recurrently ran into the problem of different displays of remote and local displays of temperatures. In a bulletin from MAN B&W it was stated:

MAN B&W’s problem:“The electronic measurement (thermocouple) of exhaust gas temperatures shows a tendency towards lower values (5 - 10 %) than the mechanical measure-ment (local). Check measurements in liquid baths or block calibrators show no signifi cant deviations.”

MECHATRONIC THERMOMETER A86 SPECIFICATIONS Case DN100, Stainless Steel AISI304Front Front ring: AISI316 Toughened glassStem Ø13, Stainless Steel AISI304, L140-L560 mmVibration damping Silicone oil (12500 cSt)Vibration 3-25 hz Amplitude 1,6mm 25- hz Acc. 4g.Ambient temp. -40-100 °CEnclosure IP68Connections Compression fi tting or unions Mechanical instrument Gas pressure Measuring range 0-600 °C or 50-650 °CAccuracy Euro Standard EN13190 Class 1. Electronic sensor Thermocouple type KMeasuring range -40-1000 °CAccuracy DIN 43721 Class 2. Amplifi er / Converter K420 Input Thermocouple Type KOutput 4-20 mA (0-600 °C)Supply 18-32 VdcMax load 250 ohmAccuracy ±0,2%FS ±1 °CZero ±5%Span ±15%Reacting time compensation Pre-adjusted to A86 instrumentTemp. compensation -5+70 °COperating temperature -5+70 °C

Solution from Tempress:The problem has been solved with the new-developed converter for remote display. The signal of the thermo-couple is transformed via a converter into a 4-20 mA signal, which is connected to the vessel’s alarm and monitoring system. Tempress has developed its own converter for this exact purpose, which in addition to normal adjustments of span and zero point also has an adjustment of the time constant. This implies that the electronic measurement is adjusted to match the mechanic measurement, thus the temperature display will be uniform under all operating conditions.

Mechatronic Thermometer Type A86

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