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FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
Definition statement
This subclass/group covers:

Furnaces in general, kilns, ovens, retorts or furnaces for open sintering.

References relevant to classification in this subclass
This subclass/group does not cover:

Specially adapted for bakery ovens

Specially adapted for glass melting furnaces

Specially adapted for coke or gas-making apparatus

Specially adapted for apparatus for cracking hydrocarbons

Specially adapted for blast furnaces

Specially adapted for converters for making steel

Specially adapted for furnaces for heat treating metal

Furnaces for electro-slag or arc re-melting of metals

Enamelling ovens

Informative references
Attention is drawn to the following places, which may be of interest for search:

Combustion apparatus

Heat exchanger

Electric heating

Special rules of classification within this subclass

Indexing Codes should be used as additional information or in case an EC symbol is given and more detailed Indexing Codes are existing, these more detailed Indexing Codes should also be given.

Shaft or like vertical or substantially vertical furnaces (for preheating, burning, calcining or cooling lime, magnesia or dolomite C04B 2/12)
References relevant to classification in this group
This subclass/group does not cover:

Blast furnaces

Informative references
Attention is drawn to the following places, which may be of interest for search:

Preheating, burning, calcining or cooling lime, magnesia or dolomite

Arrangements of linings (linings in general F27D 1/00)
Informative references
Attention is drawn to the following places, which may be of interest for search:

Linings in general

Arrangements of tuyeres
References relevant to classification in this group
This subclass/group does not cover:

Tuyeres for blast furnaces

Arrangements of devices for charging
References relevant to classification in this group
This subclass/group does not cover:

Bell and hopper arrangement for blast furnaces and appliances for distributing the burden

Informative references
Attention is drawn to the following places, which may be of interest for search:

Charging for furnaces in details

Arrangements of devices for discharging
References relevant to classification in this group
This subclass/group does not cover:

Discharging devices for blast furnaces

Informative references
Attention is drawn to the following places, which may be of interest for search:

Discharging for furnaces in details

Arrangements of heat-exchange apparatus (heat-exchangers in general F28C, F28D)
Informative references
Attention is drawn to the following places, which may be of interest for search:

Heat-exchanger in general

Cooling arrangements
References relevant to classification in this group
This subclass/group does not cover:

Cooling devices for blast furnaces

Informative references
Attention is drawn to the following places, which may be of interest for search:

Cooling of furnaces or of charges therein in details

Arrangements of controlling devices
Informative references
Attention is drawn to the following places, which may be of interest for search:

Controlling devices for furnaces in details

Arrangements of monitoring devices, of indicators, of alarm devices
Informative references
Attention is drawn to the following places, which may be of interest for search:

Monitoring devices for furnaces in details

Hearth-type furnaces, e.g. of reverberatory type (F27B 9/00, F27B 11/00, F27B 13/00, F27B 14/00, F27B 15/00, F27B 21/00 take precedence); Tank furnaces
References relevant to classification in this group
This subclass/group does not cover:

Furnaces for general processes of refining metals

Converters for making steel

Manufacturing of steel in electric furnaces

of multiple-hearth type; of multiple-chamber type; Combinations of hearth-type furnaces
References relevant to classification in this group
This subclass/group does not cover:

Manufacture of steel in electrically heated multi-chamber furnace, a combination of electric furnaces or an electric furnace arranged for associated working with a non electric furnace

Informative references
Attention is drawn to the following places, which may be of interest for search:

Linings in general

heated electrically, with or without any other source of heat
Informative references
Attention is drawn to the following places, which may be of interest for search:

Electric heating elements or systems for furnaces in details

Heated by electric discharge in details

Arrangements of linings
Informative references
Attention is drawn to the following places, which may be of interest for search:

Linings in general

Walls; Roofs
Informative references
Attention is drawn to the following places, which may be of interest for search:

Roofs and crowns in details

Linings and walls in details

Arrangements of devices for charging
References relevant to classification in this group
This subclass/group does not cover:

Charging of electric furnaces

Informative references
Attention is drawn to the following places, which may be of interest for search:

Devices for charging in details

Arrangements of devices for discharging
Informative references
Attention is drawn to the following places, which may be of interest for search:

Devices for discharging in details

Arrangements of heating devices
References relevant to classification in this group
This subclass/group does not cover:

Burners in electric arc furnaces

Informative references
Attention is drawn to the following places, which may be of interest for search:

Heating elements or systems in details

Burners

Electric heating

Arrangements of air or gas supply devices
References relevant to classification in this group
This subclass/group does not cover:

Injectors for electric arc furnaces

Lances or injectors for converters

Informative references
Attention is drawn to the following places, which may be of interest for search:

Introducing a fluid jet or current into the charge in details

Oxygen blowing

Cooling arrangements
Informative references
Attention is drawn to the following places, which may be of interest for search:

Cooling of furnaces or charges therein in details

Arrangements of heat-exchange apparatus
Informative references
Attention is drawn to the following places, which may be of interest for search:

Heat-exchange apparatus

Arrangement of controlling, monitoring, alarm or the like devices
Informative references
Attention is drawn to the following places, which may be of interest for search:

Controlling devices for furnaces in details

Monitoring devices for furnaces in details

F21D21/00

Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated (F27B 9/00 takes precedence)
References relevant to classification in this group
This subclass/group does not cover:

Furnaces through which the charge is moved mechanically

Furnaces for heat treatment

Muffle furnaces

C21D9/006

adapted for treating the charge in vacuum or special atmosphere
References relevant to classification in this group
This subclass/group does not cover:

Heat treatment in controlled atmosphere

Furnaces for heat treatment

Informative references
Attention is drawn to the following places, which may be of interest for search:

Forming, maintaining or circulating atmosphere in heating chambers in details

Arrangements of linings
Informative references
Attention is drawn to the following places, which may be of interest for search:

Linings in general

Arrangement of devices for charging
References relevant to classification in this group
This subclass/group does not cover:

Charging for metallic articles for heat treatment

Informative references
Attention is drawn to the following places, which may be of interest for search:

Charging devices for furnaces in details

Arrangement of devices for discharging
References relevant to classification in this group
This subclass/group does not cover:

Discharging for metallic articles for heat treatment

Informative references
Attention is drawn to the following places, which may be of interest for search:

Discharging devices for furnaces in details

Arrangements of heating devices
References relevant to classification in this group
This subclass/group does not cover:

Methods of heating during heat treatment

Informative references
Attention is drawn to the following places, which may be of interest for search:

Heating elements or systems in details

Arrangement of elements for electric heating in or on furnaces in details

Arrangements of air or gas supply devices
References relevant to classification in this group
This subclass/group does not cover:

Methods of heat treatment in inert gas

Rotary-drum furnaces

Informative references
Attention is drawn to the following places, which may be of interest for search:

Supplying steam, vapour, gases or liquids in heating chambers

Arrangement of controlling, monitoring, alarm or like devices
References relevant to classification in this group
This subclass/group does not cover:

Process control of heat treatment

Informative references
Attention is drawn to the following places, which may be of interest for search:

Controlling devices for furnaces in details

Monitoring devices for furnaces in details

F21D21/00

Rotary-drum furnaces, i.e. horizontal or slightly inclined
References relevant to classification in this group
This subclass/group does not cover:

Rotary retorts

Destructive distillation of solid carbonaceous material with indirect heating in rotary ovens or retorts

Making pig iron in rotary kilns

Making spongy iron or liquid steel, by direct processes in rotary furnaces

Rotary furnaces for heat treatment

Informative references
Attention is drawn to the following places, which may be of interest for search:

Burning or melting of hydraulic cements

Incineration of waste in rotating drum

adapted for treating the charge in vacuum or special atmosphere
References relevant to classification in this group
This subclass/group does not cover:

Heat treatment in controlled atmosphere

Informative references
Attention is drawn to the following places, which may be of interest for search:

Forming or maintaining special atmospheres or vacuum in heating chambers in details

Details, accessories, or equipment peculiar to rotary-drum furnaces
Informative references
Attention is drawn to the following places, which may be of interest for search:

Burning or melting of hydraulic cements

Seals between rotary and stationary parts
Informative references
Attention is drawn to the following places, which may be of interest for search:

Seals for furnaces in details

Arrangements of linings
Informative references
Attention is drawn to the following places, which may be of interest for search:

Linings for furnaces in details

Arrangements of partitions
Informative references
Attention is drawn to the following places, which may be of interest for search:

Partitions for furnaces in details

Arrangement of devices for charging
Informative references
Attention is drawn to the following places, which may be of interest for search:

Devices for charging for furnaces in details

Arrangement of devices for discharging
Informative references
Attention is drawn to the following places, which may be of interest for search:

Devices for charging of furnaces in details

Arrangements of cooling devices
Definition statement
This subclass/group covers:

Arrangements of cooling devices

Informative references
Attention is drawn to the following places, which may be of interest for search:

Cooling of furnaces or charges therein in details

Planetary coolers
Definition statement
This subclass/group covers:

Planetary coolers

Informative references
Attention is drawn to the following places, which may be of interest for search:

Cooling of furnaces or charges therein in details

Arrangement of controlling, monitoring, alarm or like devices
Informative references
Attention is drawn to the following places, which may be of interest for search:

Controlling devices for furnaces in details

Monitoring devices for furnaces in details

F21D21/00

Furnaces through which the charge is moved mechanically, e.g. of tunnel type (F27B 7/14 takes precedence); Similar furnaces in which the charge moves by gravity
Definition statement
This subclass/group covers:

Furnaces through which the charge is moved mechanically, e.g. tunnel furnaces; Similar furnaces in which the charge moves by gravity

References relevant to classification in this group
This subclass/group does not cover:

Rotary-drum furnaces with means for agitating or moving the charge

Furnaces for heat treatment

adapted for treating the charge in vacuum or special atmosphere
References relevant to classification in this group
This subclass/group does not cover:

Method of heat treatment in inert gas

Continuous furnace for wire with a controlled atmosphere

Informative references
Attention is drawn to the following places, which may be of interest for search:

Forming or maintaining special atmospheres or vacuum in heating chambers in details

heated without contact between combustion gases and charge; electrically heated
References relevant to classification in this group
This subclass/group does not cover:

Method of heating during heat treatment

Informative references
Attention is drawn to the following places, which may be of interest for search:

Heating elements or systems in details

Arrangement of elements for electric heating in or on furnaces in details

characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment (F27B 9/28 takes precedence; travelling or movable supports or containers for the charge F27D 3/12)
References relevant to classification in this group
This subclass/group does not cover:

Furnaces for heat treatment through which the charge is moved in horizontal path; up or down

Furnaces through which the charge is moved mechanically, for treating continuous lengths of work

Informative references
Attention is drawn to the following places, which may be of interest for search:

Travelling or movable supports or containers for the charge; Furnace cars

F27D 3/12; F27D3/12A

being carried by a conveyer {transport by conveyers in general B65G}
References relevant to classification in this group
This subclass/group does not cover:

Rolls in heat treating furnaces

Rolls in continuous heat treating furnaces

Informative references
Attention is drawn to the following places, which may be of interest for search:

Transport by conveyors in general

B65G/00

on or in trucks, sleds, or containers
Informative references
Attention is drawn to the following places, which may be of interest for search:

Travelling or movable supports or containers for the charge; Furnace cars

F27D 3/12; F27D3/12A

Arrangements of linings
Informative references
Attention is drawn to the following places, which may be of interest for search:

Linings for furnaces in details

Arrangements of heating devices
References relevant to classification in this group
This subclass/group does not cover:

Heating metal strips

Informative references
Attention is drawn to the following places, which may be of interest for search:

Heating elements or system for furnaces in details

Arrangements of devices for charging
References relevant to classification in this group
This subclass/group does not cover:

Charging metallic articles in heat treatment furnaces

Informative references
Attention is drawn to the following places, which may be of interest for search:

Devices for charging of furnaces in details

Arrangements of devices for discharging
References relevant to classification in this group
This subclass/group does not cover:

Discharging metallic articles in heat treatment furnaces

Informative references
Attention is drawn to the following places, which may be of interest for search:

Devices for discharging of furnaces in details

Arrangements of controlling or monitoring devices
Definition statement
This subclass/group covers:

Arrangement of controlling or monitoring devices

References relevant to classification in this group
This subclass/group does not cover:

Process control for heat treatment

Informative references
Attention is drawn to the following places, which may be of interest for search:

Controlling devices for furnaces in details

Monitoring devices for furnaces in details

F21D21/00

Bell-type furnaces (for treating metal strips or wire C21D 9/663)
References relevant to classification in this group
This subclass/group does not cover:

Bell-type furnaces for treating metal strips or wire

Arrangements of linings
Informative references
Attention is drawn to the following places, which may be of interest for search:

Linings for furnaces in details

Arrangements of heating devices
Informative references
Attention is drawn to the following places, which may be of interest for search:

Heating elements or systems in details; especially burners

Arrangement of controlling, monitoring, alarm or like devices
Informative references
Attention is drawn to the following places, which may be of interest for search:

Controlling devices for furnaces in details

Monitoring devices for furnaces in details

F21D21/00

Crucible or pot furnace
Informative references
Attention is drawn to the following places, which may be of interest for search:

Single crystal growth

adapted for treating the charge in vacuum or special atmosphere
Informative references
Attention is drawn to the following places, which may be of interest for search:

Forming, maintaining or circulating atmosphere in heating chambers in details

heated electrically, e.g. induction crucible furnaces with or without any other source of heat (F27B 14/04 takes precedence)
Informative references
Attention is drawn to the following places, which may be of interest for search:

Electric heating elements or systems

Electric heating elements in general

Crucibles
Informative references
Attention is drawn to the following places, which may be of interest for search:

Crucibles for single crystal growth

Covers therefor
Informative references
Attention is drawn to the following places, which may be of interest for search:

Covers for furnaces in details

Arrangements of heating devices
Informative references
Attention is drawn to the following places, which may be of interest for search:

Heating elements or systems for furnaces in details

Arrangement of controlling, monitoring, alarm or like devices
Informative references
Attention is drawn to the following places, which may be of interest for search:

Controlling devices for furnaces in details

Monitoring devices for furnaces in details

F21D21/00

Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion {(apparatus in general for carrying out chemical or physical processes in a fluidised bed reactor B01J 8/24 to B01J 8/44)}
Definition statement
This subclass/group covers:

Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion.

References relevant to classification in this group
This subclass/group does not cover:

Making spongy iron or liquid steel, by direct processes in fluidised bed furnaces or apparatus containing a dispersion of the material

Heating metallic strips in fluidized beds

Informative references
Attention is drawn to the following places, which may be of interest for search:

General apparatuses for carrying out chemical or physical processes in a fluidised-bed reactor

Heat exchange apparatus using fluidized bed

Arrangements of linings
Informative references
Attention is drawn to the following places, which may be of interest for search:

Linings for furnaces in details

Arrangements of devices for charging
Informative references
Attention is drawn to the following places, which may be of interest for search:

Devices for charging of furnaces in details

Arrangements of devices for discharging
Informative references
Attention is drawn to the following places, which may be of interest for search:

Devices for discharging of furnaces in details

Arrangements of controlling devices
Informative references
Attention is drawn to the following places, which may be of interest for search:

Controlling devices for furnaces in details

Arrangements of monitoring devices, of indicators, of alarm devices
Informative references
Attention is drawn to the following places, which may be of interest for search:

Monitoring devices for furnaces in details

Furnaces of a kind not covered by any preceding group (structural combinations of furnaces F27B 19/02)
Definition statement
This subclass/group covers:

Furnaces of a kind not covered by any preceding group;

open field furnaces for burning bricks;

chamber-type furnaces, also adapted for treating semiconductor wafers;

furnaces, where the floor consists of the support carrying the charge, e.g. car type furnaces;

furnaces for burning bricks or pottery;

References relevant to classification in this group
This subclass/group does not cover:

Furnaces coilers

Furnace for ingots

Informative references
Attention is drawn to the following places, which may be of interest for search:

Apparatuses for treating semiconductors/wafers

Furnaces through which the charge is moved mechanically

specially designed for laboratory use
Definition statement
This subclass/group covers:

Furnaces especially designed for laboratory use.

Furnaces for dental work-pieces

Informative references
Attention is drawn to the following places, which may be of interest for search:

Devices for soldering, casting, moulding or melting dental prostheses

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Last Modified: 10/11/2013