Glossary of Terms

Here you will find a glossary of specialised terms commonly used in thermostating and metrology.

I

Ignition temperature

The ignition temperature is the lowest temperature at which a flammable substance in an air-liquid mixture ignites spontaneously and continues to burn without any addition of heat.

Immersion cooler

An additional chiller which is connected by means of a flexible and refrigerant-tight tube to a cooling coil for immersion and cooling of any desired bath.

Immersion thermostat

A thermostat that can be combined with a bath and so forms a separate unit. Immersion thermostats are equipped with a screw clamp to attach them to any desired bath wall or can be fixed on a stand.

Inherent viscosity (logarithmic viscosity coefficient)

The natural logarithm of the relative viscosity based on concentration C of the dissolved substance.

Injection control

With LAUDA process cooling units, the cooling power (see cooling power) is permanently controlled by adjusting the injection flow (0 - 100 %). The final control element is a continuously working control valve that is placed in the feeding pipe of the refrigerant in front of the evaporator. If several compressors are shunted, an automatic cascade connection (compressor controlled) ensures energy-saving partial-load operation.

Insulation type IP

As per EN 60529. The first figure states protection against contact and foreign bodies, the second figure protection against water. E.g., IP 32: 3 means protection against contact with dangerous parts located inside by using a tool of greater/equals 2.5 mm in diameter and up to 100 mm length. 2 means protection against drip water at angles of 15°. The assessment is done as per EN 61010-1 (see "Standards"). In the LAUDA range a statement of the IP type of insulation is only done for the Integral process thermostats and the WK circulation chillers.

Interface

Always serves to exchange data and may be set up on an analogue basis (mostly standard signal 4-20 mA or 0-10 V) or on a digital basis. In the digital area you find the single serial interfaces (RS 232) or the more powerful, parallel addressable systems for many users (RS 485 or the different industrial bus systems).

Interface, analogue

Used to input the set value or to output the actual value of temperature in analogue form, generally in the form of a reference signal with voltage (0 ... 10 V) or current (0/4 ... 20 mA) respectively.

Interface, digital

Used to transfer data between connected units in digital form via data cable. The set and actual temperature values are the main items transferred. The RS 232 interface is of serial type and allows a point-to-point connection. This means that at anyone time only two participants such as the thermostat and the PC can communicate with each other via the interface. The RS 485 interface is an addressable interface to which up to 32 participants can be connected. Each participant of the bus system has its own address.

Interfacial energy

The sum of free energy of all the molecules present in the interface between different materials. The interface between a liquid and a gas is designated as the surface and the corresponding energy from this region is the surface energy.

Interfacial tension

The work that must be applied to increase the interface of the liquid by one surface area unit. This is equivalent to the specific interfacial energy.

Intrinsic temperature

The operating temperature of a heating thermostat that is reached when the heating is switched off in a stationary condition. It depends on the pump capacity, the bath liquid used and the installation of the thermostat, i.e. with or without a bath cover. The working temperature range only starts approximately 3 °C above the intrinsic temperature.

Intrinsic viscosity (limiting viscosity number, Staudinger index, IV value)

The limiting value of the reduced/inherent viscosity for the case of infinitely severely diluted solvents at disappearing shearing strengths:

It is determined by measuring the vred as a function of the concentration and extrapolation on C = 0. For many polymers, there are approximation conditions based on the measurement of only one concentration usually specified in standards.

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