G
SECTION G — PHYSICS
 G

Note(s)

  1. 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).
  2. 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 G01 and "control" and "regulation" in class G05.
  3. 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 (G09), for enabling the result of a measurement to be known (G01), for signalling the information to a distant point or for giving information which has been signalled from a distant point (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 (G01L) or about some other condition linked to the pressure (another subclass of class G01, e.g., G01K for temperature), to make a record of the pressure or of its occurrence (G07C), to give an alarm (G08B), or to control another apparatus (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 G06M); TESTING
 G01

Note(s)

  1. 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.
  2. 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.

  3. Attention is drawn to the Notes following the titles of class B81 and subclass B81B relating to "micro-structural devices" and "micro-structural systems" and the Notes following the title of subclass B82B relating to "nano-structures". [7]
  4. Attention is drawn to the Notes following the title of section G, especially as regards the definition of the term "variable".
  5. 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 G01D for expression of the measurement, and finally the place for the overall system, if any.  [6]

  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 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 compensating readings of instruments for variations in temperature, see G01D or relevant subclass for variable measured; radiation pyrometry G01J; investigating or analysing materials by use of thermal means G01N 25/00; compound sensitive elements, e.g. bimetallic, G12B 1/02)
 G01K

Note(s)

  1. In this subclass, the following term is used with the meaning indicated:
    • "thermometer" includes thermally-sensitive elements not provided for in other subclasses.
  2. Attention is drawn to the Notes following the title of class 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
P:90 G01K 1/00
Details of thermometers not specially adapted for particular types of thermometer (circuits for reducing thermal inertia 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
P:30 G01K 3/00
Thermometers giving results other than momentary value of temperature (G01K 7/42 takes precedence; using thermo-electric elements G01K 7/02)  [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; 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
P:70 G01K 5/00
Measuring temperature based on the expansion or contraction of a material (G01K 9/00 takes precedence; giving other than momentary value of temperature G01K 3/00; of vapour arising from a liquid G01K 11/02; thermally-actuated switches 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 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 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 (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 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 G01K 11/04; pressure-measuring devices in general G01L)
 G01K 5/34
·  ·  the body being a capsule (G01K 5/36, 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 (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
P:50 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 G01K 3/00; measuring electric or magnetic variables G01R)
 G01K 7/01
·  using semiconducting elements having PN junctions (G01K 7/02, G01K 7/16, 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 H01L 35/00, 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 H01C, H01L)
 G01K 7/18
·  ·  the element being a linear resistance, e.g. platinum resistance thermometer (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 (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 H01G)
 G01K 7/36
·  using magnetic elements, e.g. magnets, coils (magnetic elements per se 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]
P:60 G01K 9/00
Measuring temperature based on movements caused by redistribution of weight, e.g. tilting thermometer (not giving momentary value of temperature G01K 3/00)
P:80 G01K 11/00
Measuring temperature based on physical or chemical changes not covered by group G01K 3/00, G01K 5/00, G01K 7/00, or 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 (G01K 11/32 takes precedence; heat-sensitive sheets for use in thermography 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 (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 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]
P:40 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 G01K 1/16)
 G01K 13/12
·  combined with sampling devices for measuring temperatures of samples of material
P:20 G01K 15/00
Testing or calibrating of thermometers
P:10 G01K 17/00
Measuring quantity of heat (measuring temperature by calorimetry G01K 3/00-G01K 11/00; specially adapted for measuring thermal properties of materials, e.g. specific heat, heat of combustion, 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 (G01K 17/02, 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 mechanical 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
P:0 G01K 19/00
Testing or calibrating calorimeters