|  | G |
SECTION G — PHYSICS

|  | G |
Note(s) In this section, the following term is used with the meaning indicated: "variable" (as a noun) means a feature or property (e.g., a dimension, a physical condition such as temperature, a quality such as density or colour) which, in respect of a particular entity (e.g., an object, a quantity of a substance, a beam of light) and at a particular instant, is capable of being measured; the variable may change, so that its numerical expression may assume different values at different times, in different conditions or in individual cases, but may be constant in respect of a particular entity in certain conditions or for practical purposes (e.g., the length of a bar may be regarded as constant for many purposes). Attention is drawn to the definitions of terms or expressions used, appearing in the notes of several of the classes in this section, in particular those of "measuring" in class Fulltext... Hierarchy... Expanded...G01 and "control" and "regulation" in class Fulltext... Hierarchy... Expanded...G05. Classification in this section may present more difficulty than in other sections, because the distinction between different fields of use rests to a considerable extent on differences in the intention of the user rather than on any constructional differences or differences in the manner of use, and because the subjects dealt with are often in effect systems or combinations, which have features or parts in common, rather than "things", which are readily distinguishable as a whole. For example, information (e.g., a set of figures) may be displayed for the purpose of education or advertising (Fulltext... Hierarchy... Expanded...G09), for enabling the result of a measurement to be known (Fulltext... Hierarchy... Expanded...G01), for signalling the information to a distant point or for giving information which has been signalled from a distant point (Fulltext... Hierarchy... Expanded...G08). The words used to describe the purpose depend on features that may be irrelevant to the form of the apparatus concerned, for example, such features as the desired effect on the person who sees the display, or whether the display is controlled from a remote point. Again, a device which responds to some change in a condition, e.g., in the pressure of a fluid, may be used, without modification of the device itself, to give information about the pressure (Fulltext... Hierarchy... Expanded...G01L) or about some other condition linked to the pressure (another subclass of class Fulltext... Hierarchy... Expanded...G01, e.g., Fulltext... Hierarchy... Expanded...G01K for temperature), to make a record of the pressure or of its occurrence (Fulltext... Hierarchy... Expanded...G07C), to give an alarm (Fulltext... Hierarchy... Expanded...G08B), or to control another apparatus (Fulltext... Hierarchy... Expanded...G05). The classification scheme is intended to enable things of a similar nature (as indicated above) to be classified together. It is therefore particularly necessary for the real nature of any technical subject to be decided before it can be properly classified.

INSTRUMENTS

|  | G01 |
MEASURING (counting Fulltext... Hierarchy... Expanded...G06M); TESTING

|  | G01 |
Note(s) This class covers, in addition to "true" measuring instruments, other indicating or recording devices of analogous construction, and also signalling or control devices insofar as they are concerned with measurement (as defined in Note 2 below) and are not specially adapted to the particular purpose of signalling or control. In this class, the following term is used with the meaning indicated: "measuring" is used to cover considerably more than its primary or basic meaning. In this primary sense, it means finding a numerical expression of the value of a variable in relation to a unit or datum or to another variable of the same nature, e.g. expressing a length in terms of another length as in measuring a length with a scale; the value may be obtained directly (as just suggested) or by measuring some other variable of which the value can be related to the value of the required variable, as in measuring a change in temperature by measuring a resultant change in the length of a column of mercury. However, since the same device or instrument may, instead of giving an immediate indication, be used to produce a record or to initiate a signal to produce an indication or control effect, or may be used in combination with other devices or instruments to give a conjoint result from measurement of two or more variables of the same or different kinds, it is necessary to interpret "measuring" as including also any operation that would make it possible to obtain such a numerical expression by the additional use of some way of converting a value into figures. Thus the expression in figures may be actually made by a digital presentation or by reading a scale, or an indication of it may be given without the use of figures, e.g. by some perceptible feature (variable) of the entity (e.g. object, substance, beam of light) of which the variable being measured is a property or condition or by an analogue of such a feature (e.g. the corresponding position of a member without any scale, a corresponding voltage generated in some way). In many cases there is no such value indication but only an indication of difference or equality in relation to a standard or datum (of which the value may or may not be known in figures); the standard or datum may be the value of another variable of the same nature but of a different entity (e.g. a standard measure) or of the same entity at a different time. In its simplest form, measurement may give merely an indication of presence or absence of a certain condition or quality, e.g. movement (in any direction or in a particular direction), or whether a variable exceeds a predetermined value. Attention is drawn to the Notes following the title of section G, especially as regards the definition of the term "variable". In many measuring arrangements, a first variable to be measured is transformed into a second, or further, variables. The second, or further, variables may be (a) a condition related to the first variable and produced in a member, or (b) a displacement of a member. Further transformation may be needed. [6] When classifying such an arrangement, (i) the transformation step, or each transformation step, that is of interest is classified, or (ii) if interest lies only in the system as a whole, the first variable is classified in the appropriate place. [6] This is particularly important where two or more conversions take place, for instance where a first variable, for example pressure, is transformed into a second variable, for example an optical property of a sensing body, and that second variable is expressed by means of a third variable, for example an electric effect. In such a case, the following classification places should be considered: the place for the transformation of the first variable, that for sensing the condition caused by that variable, subclass Fulltext... Hierarchy... Expanded...G01D for expression of the measurement, and finally the place for the overall system, if any. [6] The measurement of change in the value of a physical property is classified in the same subclass as the measurement of that physical property, e.g. measurement of expansion of length is classified in subclass Fulltext... Hierarchy... Expanded...G01B.

|  | G01K |
MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (sensing temperature changes for compensating measurements of other variables or for compensing readings of instruments for variations in temperature, see Fulltext... Hierarchy... Expanded...G01D or relevant subclass for variable measured; radiation pyrometry Fulltext... Hierarchy... Expanded...G01J; investigating or analysing materials by use of thermal means Fulltext... Hierarchy... Expanded...G01N 25/00; compound sensitive elements, e.g. bimetallic, Fulltext... Hierarchy... Expanded...G12B 1/02)

|  | G01K |
Note(s) In this subclass, the following term is used with the meaning indicated: "thermometer" includes thermally-sensitive elements not provided for in other subclasses. Attention is drawn to the Notes following the title of class Fulltext... Hierarchy... Expanded...G01.

|  | G01K |
Subclass index
MEASURING TEMPERATURE |
characterised by principle of operation | 5/00, 7/00, 9/00, 11/00
Thermometers giving an indication other than the instantaneous value | 3/00
Details of thermometers not specially adapted for particular types of thermometers | 1/00
Adaptations of thermometers for specific purposes | 13/00
Testing and calibrating of thermometers | 15/00
MEASURING QUANTITY OF HEAT; TESTING AND CALIBRATING OF CALORIMETERS | 17/00; 19/00

|  | G01K 1/00 |
Details of thermometers not specially adapted for particular types of thermometer (circuits for reducing thermal inertia Fulltext... Hierarchy... Expanded...G01K 7/42) [6]

|  | G01K 1/02 |
· | Special applications of indicating or recording means, e.g. for remote indications

|  | G01K 1/04 |
· · | Scales

|  | G01K 1/06 |
· · · | Arrangements for facilitating reading, e.g. illumination, magnifying glass

|  | G01K 1/08 |
· | Protective devices, e.g. casings

|  | G01K 1/10 |
· · | for preventing chemical attack

|  | G01K 1/12 |
· · | for preventing damage due to heat overloading

|  | G01K 1/14 |
· | Supports; Fastening devices; Mounting thermometers in particular locations

|  | G01K 1/16 |
· | Special arrangements for conducting heat from the object to the sensitive element

|  | G01K 1/18 |
· · | for reducing thermal inertia

|  | G01K 1/20 |
· | Compensating for effects of temperature changes other than those to be measured, e.g. changes in ambient temperature

|  | G01K 1/22 |
· · | by means of fluid contained in a hollow body having parts which are deformable or displaceable under the pressure developed by the fluid

|  | G01K 1/24 |
· · | by means of compounded strips or plates, e.g. bimetallic strips

|  | G01K 1/26 |
· | Compensating for effects of pressure changes

|  | G01K 3/00 |
Thermometers giving results other than momentary value of temperature (Fulltext... Hierarchy... Expanded...G01K 7/42 takes precedence) [6]

|  | G01K 3/02 |
· | giving mean values; giving integrated values

|  | G01K 3/04 |
· · | in respect of time

|  | G01K 3/06 |
· · | in respect of space

|  | G01K 3/08 |
· | giving differences of values (using thermo-electric elements Fulltext... Hierarchy... Expanded...G01K 7/02); giving differentiated values

|  | G01K 3/10 |
· · | in respect of time, e.g. reacting only to a quick change of temperature

|  | G01K 3/12 |
· · · | based upon expansion or contraction of materials

|  | G01K 3/14 |
· · | in respect of space

|  | G01K 5/00 |
Measuring temperature based on the expansion or contraction of a material (Fulltext... Hierarchy... Expanded...G01K 9/00 takes precedence; giving other than momentary value of temperature Fulltext... Hierarchy... Expanded...G01K 3/00; of vapour arising from a liquid Fulltext... Hierarchy... Expanded...G01K 11/02; thermally-actuated switches Fulltext... Hierarchy... Expanded...H01H)

|  | G01K 5/02 |
· | the material being a liquid (contained in a hollow body having parts which are deformable or displaceable under the pressure developed by the material Fulltext... Hierarchy... Expanded...G01K 5/32)

|  | G01K 5/04 |
· · | Details

|  | G01K 5/06 |
· · · | Arrangements for driving back the liquid column

|  | G01K 5/08 |
· · · | Capillary tubes

|  | G01K 5/10 |
· · · | Containers for the liquid

|  | G01K 5/12 |
· · · | Selection of liquid compositions

|  | G01K 5/14 |
· · | the liquid displacing a further liquid column or a solid body (for maximum or minimum indication Fulltext... Hierarchy... Expanded...G01K 5/20)

|  | G01K 5/16 |
· · | with electric contacts

|  | G01K 5/18 |
· · | with electric conversion means for final indication

|  | G01K 5/20 |
· · | with means for indicating a maximum or a minimum or both (Fulltext... Hierarchy... Expanded...G01K 5/22 takes precedence)

|  | G01K 5/22 |
· · | with provision for expansion indicating over not more than a few degrees, e.g. clinical thermometer

|  | G01K 5/24 |
· · | with provision for measuring the difference between two temperatures

|  | G01K 5/26 |
· · | with provision for adjusting zero point of scale, e.g. Beckmann thermometer

|  | G01K 5/28 |
· | the material being a gas (contained in a hollow body having parts which are deformable or displaceable under the pressure developed by the material Fulltext... Hierarchy... Expanded...G01K 5/32)

|  | G01K 5/30 |
· · | the gas displacing a liquid column

|  | G01K 5/32 |
· | the material being a fluid contained in a hollow body having parts which are deformable or displaceable under the pressure developed by the material (under pressure developed by evaporation Fulltext... Hierarchy... Expanded...G01K 11/04; pressure-measuring devices in general Fulltext... Hierarchy... Expanded...G01L)

|  | G01K 5/34 |
· · | the body being a capsule (Fulltext... Hierarchy... Expanded...G01K 5/36, Fulltext... Hierarchy... Expanded...G01K 5/42 take precedence)

|  | G01K 5/36 |
· · | the body being a tubular spring, e.g. Bourdon tube

|  | G01K 5/38 |
· · · | of spiral formation

|  | G01K 5/40 |
· · · | of helical formation

|  | G01K 5/42 |
· · | the body being a bellows

|  | G01K 5/44 |
· · | the body being a cylinder and piston

|  | G01K 5/46 |
· · | with electric conversion means for final indication

|  | G01K 5/48 |
· | the material being a solid

|  | G01K 5/50 |
· · | arranged for free expansion or contraction

|  | G01K 5/52 |
· · · | with electrical conversion means for final indication

|  | G01K 5/54 |
· · | consisting of pivotally-connected elements

|  | G01K 5/56 |
· · | constrained so that expansion or contraction causes a deformation of the solid

|  | G01K 5/58 |
· · · | the solid body being constrained at more than one point, e.g. rod, plate, diaphragm (Fulltext... Hierarchy... Expanded...G01K 5/62 takes precedence)

|  | G01K 5/60 |
· · · · | the body being a flexible wire or ribbon

|  | G01K 5/62 |
· · · | the solid body being formed of compounded strips or plates, e.g. bimetallic strip

|  | G01K 5/64 |
· · · · | Details of the compound system

|  | G01K 5/66 |
· · · · · | Selection of composition of the components of the system

|  | G01K 5/68 |
· · · · · | Shape of the system

|  | G01K 5/70 |
· · · · | specially adapted for indicating or recording

|  | G01K 5/72 |
· · · · · | with electric transmission means for final indication

|  | G01K 7/00 |
Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat (giving results other than momentary value of temperature Fulltext... Hierarchy... Expanded...G01K 3/00; measuring electric or magnetic variables Fulltext... Hierarchy... Expanded...G01R)

|  | G01K 7/01 |
· | using semiconducting elements having PN junctions (Fulltext... Hierarchy... Expanded...G01K 7/02, Fulltext... Hierarchy... Expanded...G01K 7/16, Fulltext... Hierarchy... Expanded...G01K 7/30 take precedence) [6]

|  | G01K 7/02 |
· | using thermo-electric elements, e.g. thermo-couples (thermo-electric or thermo-magnetic devices per se Fulltext... Hierarchy... Expanded...H01L 35/00, Fulltext... Hierarchy... Expanded...H01L 37/00)

|  | G01K 7/04 |
· · | the object to be measured not forming one of the thermo-electric materials

|  | G01K 7/06 |
· · · | the thermo-electric materials being arranged one within the other with the junction at one end exposed to the object, e.g. sheathed type

|  | G01K 7/08 |
· · | the object to be measured forming one of the thermo-electric materials, e.g. pointed type

|  | G01K 7/10 |
· · | Arrangements for compensating for auxiliary variables, e.g. length of lead

|  | G01K 7/12 |
· · · | Arrangements with respect to the cold junction, e.g. preventing influence of temperature of surrounding air

|  | G01K 7/13 |
· · · · | Circuits for cold-junction compensation [6]

|  | G01K 7/14 |
· · | Arrangements for modifying the output characteristic, e.g. linearising

|  | G01K 7/16 |
· | using resistive elements (resistive elements per se Fulltext... Hierarchy... Expanded...H01C, Fulltext... Hierarchy... Expanded...H01L)

|  | G01K 7/18 |
· · | the element being a linear resistance, e.g. platinum resistance thermometer (Fulltext... Hierarchy... Expanded...G01K 7/26 takes precedence)

|  | G01K 7/20 |
· · · | in a specially-adapted circuit, e.g. bridge circuit

|  | G01K 7/21 |
· · · · | for modifying the output characteristic, e.g. linearising [6]

|  | G01K 7/22 |
· · | the element being a non-linear resistance, e.g. thermistor (Fulltext... Hierarchy... Expanded...G01K 7/26 takes precedence)

|  | G01K 7/24 |
· · · | in a specially-adapted circuit, e.g. bridge circuit

|  | G01K 7/25 |
· · · · | for modifying the output characteristic, e.g. linearising [6]

|  | G01K 7/26 |
· · | the element being an electrolyte

|  | G01K 7/28 |
· · · | in a specially-adapted circuit, e.g. bridge circuit

|  | G01K 7/30 |
· | using thermal noise of resistances or conductors

|  | G01K 7/32 |
· | using change of resonant frequency of a crystal

|  | G01K 7/34 |
· | using capacitative elements (capacitors per se Fulltext... Hierarchy... Expanded...H01G)

|  | G01K 7/36 |
· | using magnetic elements, e.g. magnets, coils (magnetic elements per se Fulltext... Hierarchy... Expanded...H01F)

|  | G01K 7/38 |
· · | the variations of temperature influencing the magnetic permeability

|  | G01K 7/40 |
· | using ionisation of gases

|  | G01K 7/42 |
· | Circuits for reducing thermal inertia; Circuits for predicting the stationary value of temperature [6]

|  | G01K 9/00 |
Measuring temperature based on movements caused by redistribution of weight, e.g. tilting thermometer (not giving momentary value of temperature Fulltext... Hierarchy... Expanded...G01K 3/00)

|  | G01K 11/00 |
Measuring temperature based on physical or chemical changes not covered by group Fulltext... Hierarchy... Expanded...G01K 3/00, Fulltext... Hierarchy... Expanded...G01K 5/00, Fulltext... Hierarchy... Expanded...G01K 7/00, or Fulltext... Hierarchy... Expanded...G01K 9/00

|  | G01K 11/02 |
· | using evaporation or sublimation, e.g. by observing boiling

|  | G01K 11/04 |
· · | from material contained in a hollow body having parts which are deformable or displaceable under the pressure developed by the vapour

|  | G01K 11/06 |
· | using melting, freezing, or softening

|  | G01K 11/08 |
· · | of disposable test bodies, e.g. cone

|  | G01K 11/10 |
· | using sintering

|  | G01K 11/12 |
· | using change of colour or translucency (Fulltext... Hierarchy... Expanded...G01K 11/32 takes precedence; heat-sensitive sheets for use in thermography Fulltext... Hierarchy... Expanded...B41M 5/00) [6]

|  | G01K 11/14 |
· · | of inorganic materials

|  | G01K 11/16 |
· · | of organic materials

|  | G01K 11/18 |
· · | of materials which change translucency

|  | G01K 11/20 |
· | using thermoluminescent materials (Fulltext... Hierarchy... Expanded...G01K 11/32 takes precedence) [6]

|  | G01K 11/22 |
· | using measurement of acoustic effects

|  | G01K 11/24 |
· · | of the velocity of propagation of sound

|  | G01K 11/26 |
· · | of resonant frequencies

|  | G01K 11/28 |
· | using measurements of density (measuring density in general Fulltext... Hierarchy... Expanded...G01N)

|  | G01K 11/30 |
· | using measurement of the effect of a material on X-radiation, gamma radiation or particle radiation [5]

|  | G01K 11/32 |
· | using changes in transmission, scattering or fluorescence in optical fibres [6]

|  | G01K 13/00 |
Adaptations of thermometers for specific purposes

|  | G01K 13/02 |
· | for measuring temperature of moving fluids or granular materials capable of flow

|  | G01K 13/04 |
· | for measuring temperature of moving solid bodies

|  | G01K 13/06 |
· · | in linear movement

|  | G01K 13/08 |
· · | in rotary movement

|  | G01K 13/10 |
· | for measuring temperature within piled or stacked materials (by special arrangements for conducting heat from the object to the sensitive element Fulltext... Hierarchy... Expanded...G01K 1/16)

|  | G01K 13/12 |
· | combined with sampling devices for measuring temperatures of samples of material

|  | G01K 15/00 |
Testing or calibrating of thermometers

|  | G01K 17/00 |
Measuring quantity of heat (measuring temperature by calorimetry Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01K 3/00-G01K 11/00; specially adapted for measuring thermal properties of materials, e.g. specific heat, heat of combustion, Fulltext... Hierarchy... Expanded...G01N)

|  | G01K 17/02 |
· | Calorimeters using transport of an indicating substance, e.g. evaporation calorimeters

|  | G01K 17/04 |
· | Calorimeters using compensation methods

|  | G01K 17/06 |
· | Measuring quantity of heat conveyed by flowing media, e.g. in heating systems (Fulltext... Hierarchy... Expanded...G01K 17/02, Fulltext... Hierarchy... Expanded...G01K 17/04 take precedence)

|  | G01K 17/08 |
· · | based upon measurement of temperature difference

|  | G01K 17/10 |
· · · | between an inlet and an outlet point, combined with measurement of rate of flow of the medium

|  | G01K 17/12 |
· · · · | Indicating product of flow and temperature difference directly

|  | G01K 17/14 |
· · · · · | using mechnical means for both measurements

|  | G01K 17/16 |
· · · · · | using electrical means for both measurements

|  | G01K 17/18 |
· · · · · | using electrical means for one measurement and mechanical means for the other

|  | G01K 17/20 |
· · · | across a radiating surface, combined with ascertainment of the heat-transmission coefficient

|  | G01K 19/00 |
Testing or calibrating calorimeters