Technical information

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 the user against electrical contact. This solution is possible for large enclosures. For small enclosures, special devices have been developed.

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.

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.

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,

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, and all physical variations related to temperature change: thermal expansion of gases, liquids, metals and other solids, liquefaction temperatures, boiling temperature, magnetism, thermoelectricity, just to give a few.

§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.

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.

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.

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. But they can be wound in a spiral shape, although this arrangement most often used in the construction of thermometers.

Standards EN60730 and EN 60335 define, sometimes with differences, the vocabulary to use. However, it is often different from that used in practice.

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 manufacture their own knobs and every existing models was designed to best fit the needs of our customers and their applications. There is no universal knob that can be used for every applications. This document define the main specifications to determine the most appropriate adjustment knob.

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, ensuring measurement accuracy and repeatability. These conditions are rarely those found in practice when installing thermostats. However, with a minimum of constraints, it is possible to optimize assemblies.

It is currently the thermostats family where quantities are the most important. Numerous configurations exist, and the current trend is simplification and footprint reduction.

Although pressure is an absolute value, the current measures pressure, are usually made relative to ambient air pressure. In other cases, the measurements are compared to vacuum. This leads to confusion and errors.

Pressure switches are used to control the pressure of a medium and operate an electrical device. When pressure rises to the set point value, they switch off the equipment or switch on an alarm. Fluid they control can be air or water. There is no barometric or ambient temperature compensation in pressure switches.

Accuracy, actuating force and differential are given by membrane surface.

Pascal pressure conversion table in other current pressure measurements units

The pressure switches of this catalogue are made according to the flexible elastomeric membrane technology. The pressure applied deforms the membrane which then actuates an electrical contact.

Conversion table: Liter /min and liter/hour into US gallon/min and US gallon/ hour

If the level measurement, especially for meteorological purposes seems to date back to the 4th or 5th century BC in India, the development of steam boilers for locomotives and low pressure steam boilers for central heating in the first quarter of the 19th century, has quickly revealed the indispensable requirement to control the water level.

Selecting a magnet for a level switch application must take into account the characteristics of the liquid in which it will be immersed, of the temperature at which it will be subjected, of its corrosion resistance, of the magnetic field required to operate the switch and its distance to the reed switches. Sintered magnets are shock and vibration sensitive, “bonded” magnets have a low temperature resistance due to the resins used to agglomerate, and Neodymium –Iron-Boron magnets contain 60-75% iron (amount is dependent on grade) and are therefore prone to corrosion.

In antiquity, the flow measurement was one of the first means of time measurement. But it was not until the steam engines development and the need to control their water supply, that measuring devices were developed.

A certain force is required to actuate the electrical contact device. It can range from a few tenths of grams for systems with reed contacts with a power rating of 10 to 20VA (0.5Amp), to 50 grams for snap action micro-switches with a 5Amp 250V rating

Relative humidity control is relatively new, and the first mechanical devices that were used for this purpose dating from the early 20th century, and were related to the development of central heating and air conditioning, and the concept of environmental comfort.

Introduction to nylon ribbon humidistats technology (Others names: Humidostats, hygrostats, humidity switches)

To fulfill its function, especially tear strength and ingress protection, cable gland must be adapted to the diameter of the cable.

The housings are designed to protect electrical equipment located inside. This protection must be considered in the electrical and environmental angles.)

Temperature control of ambient, surface, air, liquids, pipes, by means of bulb and capillary, ambiance or rod probes.

The design of the Y0 enclosures was made to provide a starting range with a particular selection of low cost solutions. The plastic used is PC-ABC compound, with or without fiberglass reinforcement.

Y1 range includes a wide range of thermostats in IP65* metal housing with high mechanical resistance (IK10** except models with external knob), intended for commercial or industrial applications covering ranges from -35 °C to +760 °C.

Assembly examples

A unique and simple modular design

Fixed setting ambiance or Antifreeze thermostat, IP65, cable gland output, without pilot light.

The design of Ultimheat connection boxes for immersion heaters was oriented on the multiplicity of applications and therefore every possible machining.

These aluminum and plastic housings are designed for receiving and mounting electronic or electromechanical components.

Surface condition is an essential parameter of resistance against atmospheric corrosion. Both aluminum and stainless steel naturally form a protective oxide layer on the surface. Corrosion occurs only when this protective oxide layer is crossed or destroyed. Microcavities of a rough surface allow atmospheric pollutants to initiate local oxidative conditions. This is particularly critical when these pollutants have a different galvanic potential. For example, iron or iron oxide dust can create favourable conditions for perforating corrosion in stainless steel, as well as zinc in the case of aluminum. It is important that the surface of the metal, if exposed to the weather, be smooth so that these pollutants slide and escape naturally.

Mounting and coupling examples with additional housings

Assembly and applications examples

According to the Directive 2011/65/ dated June 8, 2011 (Rohs), copper alloys are allowed to have a maximum of 4% by weight of lead as an alloying element.

In Europe there are two common types of threads used on immersion heaters fittings. Threads according ISO 228-1, also said BSPP or cylindrical gas thread (G). 2mm pitch metric thread according ISO965-1, little used, which was the subject of an attempt to replace the ISO228-1 in the middle of the 20th

According to the Directive 2011/65/ dated June 8, 2011 (Rohs), stainless steel alloys are allowed to have a maximum of 0.1% by weight of lead, lead, mercury, hexavalent chromium, PBB (Polybrominated biphenyls), PBDE (Polybrominated Diphenyl Ethers) and 0.01% of Cadmium in weight.

Heating elements tubes are used in circulation heaters to heat water in swimming pools, spas, and whirlpools, and in booster heaters or main heaters in domestic central heating.

Selecting a magnet for a level switch application must take into account the characteristics of the liquid in which it will be immersed, of the temperature at which it will be subjected, of its corrosion resistance, of the magnetic field required to operate the switch and its distance to the reed switches. Sintered magnets are shock and vibration sensitive, “bonded” magnets have a low temperature resistance due to the resins used to agglomerate, and Neodymium –Iron-Boron magnets contain 60-75% iron (amount is dependent on grade) and are therefore prone to corrosion.

The plastic enclosures and their weather resistance are treated in the catalog N ° 3. We will deal here with the corrosion resistance of aluminum housings and accessories.

Heat shrinkable sleeves were invented in 1960 by the company Raychem. The tubes are made by extrusion, and subjected to molecular modification by radiation of an electron gun.

According to the Directive 2011/65/ dated June 8, 2011 (Rohs), copper alloys are allowed to have a maximum of 4% by weight of lead as an alloying element. (Provisions of Article 4 and paragraph 1 of Annex II, limit value set by 6c of Annex III)

The classic housings, with only 5 sides and a lid, require a long and costly layout, most of the time ignoring the application needs: security, fire resistance, water penetration, shocks, UV, temperature, etc.

The material was not chosen in regards of its price or ease of molding like gaskets made of PU foam injected through the process “Formed in place foam gasket or FIPFG “, or even of the possibility of die-cutting, but to meet the technical requirements of electrical heating applications: heat resistance, fire resistance, mechanical resistance to successive openings and closings, UV resistance.

According to the Directive 2011/65/ dated June 8, 2011 (Rohs), stainless steel alloys are allowed to have a maximum of 0.1% by weight of lead, lead, mercury, hexavalent chromium, PBB (Polybrominated biphenyls), PBDE (Polybrominated Diphenyl Ethers) and 0.01% of Cadmium in weight.

Hundreds of specific silicone boots have been developed during the last decade, to cover various customer requirements. This catalogue shows some of them.

Figures provided in this section are results of tests made in our laboratory. Charts were smoothened by computer, and are given for specified power and for information only.

The invention of sheathed heating elements comprising a metal tube swaged around a coiled heating wire, and which is insulated by compressed magnesia, was an essential step of the electrothermics development.

Heating elements connections (Heating elements resistance "r" of unit power "p" with nominal voltage "U")

Specific heat and density of main liquids

Average surface temperature and average air temperature of air heaters described in this catalogue

The explosion of firedamp in mines caused by the flames of oil lamps, was the cause of many accidents and caused hundreds of deaths. This explosion had a double danger: methane gas and coal dust.

Electromechanical thermostats have an important characteristic that makes critical their use in potentially explosive atmospheres: the opening and closing of their electrical contact, which occurs regularly during their normal operation, produces a spark between the contacts.

Sensors and accessories to be mounted in ISO M20x1.5 threads (type G sleeves)

As numerous mechanisms exist, we decided not to distinguish on the basis of constructive technique, but according to their operation speed, which is the key element.

Identification of terminals that are suitable for the connection of external conductors, and if they are suitable for line or neutral conductors, or both.

Hard Porcelain, originated from China, whose manufacturing process has been closely guarded for centuries, owes its characteristics of whiteness, fineness, resistance to temperature, and hardness to the use of two particular minerals, kaolin, ("Gao Ling Tu 高 岭 土 " in Chinese, which can be translated as "Clay of Gao Ling City", located north-east of Jingdezhen in Jiang Xi Province), and "Pu Tong Ci 普 通 瓷 " (translation: common ceramic).

The hexagonal crimping is the fastest way to connect two wires together, especially if this connection should be subjected to repeated thermal shocks. It is also the less bulky connection.

The solid state relay, also called solid state contactor or SSR (English acronym for Solid State Relay) is the electronic equivalent of the electromechanical power contactor.

Ceramic was the first insulating material used in the electrical connection terminals. Mechanically resistant, exceptionally fire resistant, excellent electrical insulator, it had all the qualifications. Produced from locally available raw materials, ceramic and porcelain glazed electro-technical parts were essential in the beginnings of electricity until the appearance of Bakelite in the 1930s, then of engineered thermoplastics to 1960.

In the specifications for an electromechanical thermostat, the expected life is described in terms of mechanical and electrical lifetimes.