How and where to measure the temperature?
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Globe gas and radiation combined temperature thermometer.
Using the combined temperature measurement from inside the ball and the gas temperature measurement from the exposed thermometer, a better idea of the temperatures personnel are experiencing can be made.
 
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The Benrhos Globe thermometer is designed to measure the combination of the temperature of gases and the effect of thermal radiation experienced by fire fighters during training and workers in a hot processing environment.  From our experience the thermometers used in live fire training facilities do not measure the true temperature on those near the fire.  This is mainly due to 4 reasons:

1. The thermometers are not immersed sufficiently into the space whose temperature is to be measured.  This results in a ‘stem error’ where the temperature on the cold side of the thermometer cools the stem of the thermometer on the hot side causing it to read low.  A rough guide for the immersion length would be 40 X diameter of the thermometer or more.
2. The thermometer is physically too large and hence slow to react to the temperature fluctuations it is subjected to.
3. The thermometer is not placed in the optimum position.
4. The thermometer mostly reads the temperature of the gases surrounding it and not the effect of the radiant heat.

It is always worth bearing in mind that, ‘a measurement is meaningless without an uncertainty associated with it’.  For example if the maximum temperature allowable in training is 250°C how close should you measure it ±1°C or ±10°C or even +1°C/--10°C?
 
The Combi thermometer is a development based on having a black ball that is about the size of parts of a human that are likely to get too hot, such as a hand or the back of the neck.  The ball is coated in a high emissivity coating so it absorbs most of the radiant heat that impinges on it.  Inside the ball is a fast response thermometer that measures the combined effect of the radiation and the local gas temperature to give a truer indication of what personnel would be experiencing.  Attached close to the ball is another fast response thermometer that measures the gas temperature.  Its job is to pick up any rapidly changing temperature such as a steam surge.  The temperatures can be displayed locally or transmitted via WiFi to remote locations.
 
 
 

Benrhos can help design and produce accessories for calibration laboratories such as the aluminium insert for a Fluke liquid calibration bath shown below.  Most materials can be machined including deep hole drilling of metals such as nickel alloys and Fecralloy.  Inserts for Isotech, Ametek and Fluke baths can be supplied to the customer's requirements at a competitive price.

The bath insert example above has:

1. Angled holes for probes with large heads and also enable the probes’ sensors to be closer together which will reduce the radial uncertainty contribution.
2. The threaded bar has equally spaced horizontal holes through it and pins that enable the immersion depth to be changed quickly and simply even if the insert is loaded with probes.
3. The base of the insert has small diameter holes through drilled into the probe holes so that the probe holes can be drained of liquid without having to invert the insert when it is removed.

 We have been working on simplifying the condition monitoring of fridges and freezers; with just a few non-intrusive measurements plus a calculation we can alarm the conditions shown below based on a tolerance of say being above 150% or below 30%. 
The alarm could be simply displayed or sounded locally with the option of exporting it to a monitoring system if required.  As it is so simple and non-intrusive it has the potential of being extremely cost effective.  Contact: info@benrhos.co.uk