Adjustment or reset access devices
It is often necessary, when the devices include a system of adjustment or a reset, to be able to have access to it, without having to unscrew the lid of the box. One solution is to use enclosures with an easily opening porthole or window, while protecting...
Historical introduction to temperature measurement
The temperature measurement was preceded by a long period, throughout the 18th century, when first empirically and then gradually more accurately, have been developed measurement scales, were discovered fixed points for the calibration of these scales,...
Temperature sensing principles
The bimetal strip is formed by two co-laminated metal. One has a high coefficient of expansion, the othera lower or zero. When the strip is heated, it bends proportionally to the temperature. These bimetal blades are generally flat and fixed at one end....
It is currently the thermostats family where quantities are the most important. Numerous configurations exist, and the current trend is simplification and footprint reduction.
Terminology and vocabulary used for thermostats
Standards EN60730 and EN 60335 define, sometimes with differences, the vocabulary to use. However, it is often different from that used in practice.
Important extracts of standards related to control or safety circuits
§3.8.1 All-pole cut out: Cutting in two conductors in a single operation, or for three phase units, the cut of the three conductors in a single step … Note: for three-phase, the neutral lead is not considered as a power conductor.
The proper functioning of a thermostat depends primarily on the correct choice of the component, but also the conditions of its installation. Conditions used to calibrate regulating and control equipment in the factory are always ideal laboratory conditions,...
Description of temperature controls
Used as control thermostats or as a safety thermostat with manual reset, these thermostats have a disc made of two different metals laminated together for temperature sensing element. These two metals have different expansion coefficients.
Temperature control modes
While thermostats typically operate only in the on/off mode, the electronic controllers can regulate in two main modes: on/off with adjustable differential or PID.
Heat tracing applications
To reflect the maximum temperatures allowed by the insulating polymers, the powers of flexible heating cables are generally between 5 and 30W/meter, exceptionally 40W/m and 60W/m for self-regulating cables.
Historical and technical introduction of fusible alloys and fire safety fusible links
The earliest known piece made of lead and tin alloy seems to be an Egyptian vase found in Abydos, dated around 1400 BC. During the Roman Empire, lead was used for the construction of water pipes. Melting at 325°C,
Thermostats and humidistats, how to select the right knob.
What users see from a control system is, most of time, the adjustment knob. The overall idea of the product quality is hence first based on the visual, the design, the feeling when manipulating the knob and how the adjustment adapts to the application. Ultimheat ...
Setting of knobs with adjustable span
In some applications it may be necessary to limit the temperature maximum setting (or minimum) possible by the user. Some knobs that we have developed provide this option.