U.S. PATENT AND TRADEMARK OFFICE
Information Products Division |
U.S. Patent Classification System - Classification Definitions
as of June 30, 2000
Patents classified in a subclass may be accessed by either clicking on
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Class 237
HEATING SYSTEMS
Class Definition:
Apparatus and processes for heating rooms, chambers, houses,
and other enclosing structures, including combinations of two
or more heat generators and combinations of a heat generator
with means for distributing a fluid heated thereby.
(1) Note. This class does not include the distributing means
alone unless it is peculiarly adapted for heating, nor the
heat generator alone.
(2) Note. The term "water" is used in the generic sense of
"liquid".
LINES WITH OTHER CLASSES AND WITHIN THIS CLASS
For steam traps adapted for heating systems see Class 137,
Fluid Handling, subclasses 171+, and Class 236, Automatic
Temperature and Humidity Regulation.
For methods and apparatus for heating rooms, chambers, houses
and other enclosing structures where the source of heat is
claimed to be a solar collector, classification in the
appropriate subclass in Class 126, Stoves and Furnaces.
REFERENCES TO OTHER CLASSES
SEE OR SEARCH CLASS:
34, Drying and Gas or Vapor Contact With Solids, and see the
Note to the class definition of Class 34 for the line with
Class 237.
60, Power Plants, for power plants combined with heating
apparatus which does not constitute a heating system.
62, Refrigeration, particularly subclass 90, 159+, 238.1+,
260, and 324.1+ for a refrigeration system, per se, which may
utilize the heat rejecting portion.
122, Liquid Heaters and Vaporizers, for a boiler that may
include a heat system for other than heating an enclosure.
126, Stoves and Furnaces, for a heating means that may
provide heat for a heating system.
137, Fluid Handling, appropriate subclasses, for fluid
handling and distributing systems not otherwise classifiable;
see particularly 334 for combinations of such systems with
means to heat the system or its contents (see (3) Note
above).
148, Metal Treatment, appropriate subclasses for processes of
treating solid or semi-solid metal to modify or maintain the
internal physical structure (i.e., microstructure) or
chemical property of the metal.
165, Heat Exchange, 58 ; 201+ for combined heating and
cooling processes; subclasses 201+ for automatic control of a
heating and cooling system; subclasses 48.1+ for an installed
heating and cooling system; subclasses 58+ for a heating and
cooling system; and appropriate subclasses for structure for
exchanging heat between two noncommunicating fluids not
having features specializing it for use in a heating system.
219, Electric Heating, for heating by electric current.
236, Automatic Temperature and Humidity Regulation, for
automatic heat regulation for heating systems when the
heating system is not specifically defined, the modifications
relating wholly to the control (see (3) Note above).
248, Supports, for stands, etc., adapted to support heating
apparatus.
252, Compositions, particularly 67 and 71+. Patents are
placed in Class 252 (1) claiming admixtures of ingredients,
or claims to an old compound, limited to use in a heat
transfer agent, (2) processes of transferring heat comprising
known heating system steps broadly recited, distinguished
solely by the composition or compound used, and (3) apparatus
with the composition or compound therein, where
characteristics of apparatus structure are not claimed. The
preceding are placed in Class 252, Compositions, even though
freezing or boiling points or temperatures of use are
specified.
376, Induced Nuclear Reactions: Processes, Systems, and
Elements, appropriate subclasses, particularly 402 for
reactor structures which may be adaptable for general heating
systems purposes.
405, Hydraulic and Earth Engineering, subclass 56 for a
method or apparatus for heating or cooling the earth
surrounding a fluid storage cavity; and subclasses 130+ for
heating or cooling of an earthen formation in general
417, Pumps, for pumps, per se.
418, Rotary Expansible Chamber Devices, for rotary expansible
chamber pumps, per se.
432, Heating, 121 for a residual work chamber having both
heating and work handling means; subclasses 159+ for a
residual work heating chamber in which work is heated by
contact with combustion products; and appropriate subclass
for a residual work chamber heated without the use of a
distribution system between the generator and chamber space.
454, Ventilation, for means specialized for distributing air
to rooms or buildings, even with a conventional heating
apparatus, and for rooms, buildings, cars, etc., with hollow
walls for the passage of air.
SUBCLASSES
Subclass:
1
This subclass is indented under the class definition. Means
for heating not otherwise provided for.
Subclass:
2
This subclass is indented under the class definition.
Heating systems with means for regulating temperature and
pressure independent of manual control.
SEE OR SEARCH CLASS:
236, Automatic Temperature and Humidity Regulation, for
automatic controllers when the structure of the apparatus for
heating is not specifically defined.
Subclass:
3
This subclass is indented under subclass 2. Automatic
control for heating apparatus for brooders and incubators.
SEE OR SEARCH CLASS:
119, Animal Husbandry, subclass 30, 31+, and 35+ for brooder
and incubator structure including heating systems.
Subclass:
4
This subclass is indented under subclass 3. Automatic
control for water-circulating heaters for incubators.
Subclass:
5
This subclass is indented under subclass 2. Automatic
control for heating apparatus for cars, either freight or
passenger.
SEE OR SEARCH CLASS:
126, Stoves and Furnaces, for stove structure.
Subclass:
6
This subclass is indented under subclass 5. Automatic
control for steam heating apparatus.
SEE OR SEARCH CLASS:
236, Automatic Temperature and Humidity Regulation,
especially subclass 22, for automatic control, per se.
Subclass:
7
This subclass is indented under subclass 2. Automatic
control of a unitary structure consisting of steam or water
radiators combined with a boiler.
SEE OR SEARCH CLASS:
122, Liquid Heaters and Vaporizers, for a boiler that may
include a heat system for other than heating an enclosure,
subclass 13.3 for a stand boiler (e.g., water heater, etc.)
having a delivery means to a dispense a feature (e.g.,
faucet, shower, washing machine, dishwasher, etc.).
236, Automatic Temperature and Humidity Regulation, for
controller, per se.
Subclass:
8
This subclass is indented under subclass 2. Automatic
control of water heating systems.
SEE OR SEARCH THIS CLASS, SUBCLASS:
4 for incubator heaters.
5 for car heaters.
7 for combined heater and boiler.
Subclass:
9
This subclass is indented under subclass 2. Automatic
control of steam heating systems.
SEE OR SEARCH THIS CLASS, SUBCLASS:
6 for car heaters.
7 for combined heater and boiler.
SEE OR SEARCH CLASS:
34, Drying and Gas or Vapor Contact With Solids, 535 and
549+, for heaters peculiar to Class 34 apparatus.
Subclass:
10
This subclass is indented under subclass 9. Steam heating
systems which displace the steam in the radiators by a gas,
such as air or products of combustion.
Subclass:
11
This subclass is indented under subclass 2. Automatic
control in which air is compressed and thereby heated and
circulated through the radiators.
Subclass:
12
This subclass is indented under subclass 2. Processes for
the automatic control of heating systems.
Subclass:
12.1
This subclass is indented under the class definition.
Systems combining means for generating and distributing heat
to buildings or other enclosures with means for the
production of power by a motor.
SEE OR SEARCH CLASS:
60, Power Plants, subclass 648 for a power plant that in
operation supplies heat for external use or produces a
withdrawable hot gas product.
Subclass:
12.2
This subclass is indented under subclass 12.1. Combinations
including a fire engine.
Subclass:
12.3
This subclass is indented under subclass 12.1. Combinations
including a heating system for a vehicle other than a railway
car or train.
SEE OR SEARCH THIS CLASS, SUBCLASS:
2 for similar systems claiming automatic controls.
SEE OR SEARCH CLASS:
123, Internal-Combustion Engines, subclass 142.5, for
internal combustion engines combined with means to heat the
engine or engine parts there provided for and see notes in
that subclass (142.5).
165, Heat Exchange, 43 for a heated and cooled vehicle with
a common power and heat source.
454, Ventilation, 159 for automobile heating and
ventilating.
Subclass:
12.4
This subclass is indented under subclass 12.1. Heating
systems for a car or train, combined with the locomotive or
other power plant.
Subclass:
12.5
This subclass is indented under subclass 12.4. Heating
systems in which the car or train is heated directly by the
furnace gases from the power plant.
Subclass:
12.6
This subclass is indented under subclass 12.4. Heating
systems in which the car or train is heated by a supply of
warm air supplied by the power plant.
Subclass:
12.7
This subclass is indented under subclass 12.6. Heating
systems in which the warm air is passed through radiators.
Subclass:
12.8
This subclass is indented under subclass 12.4. Heating
systems in which the car or train is heated by steam, usually
from the power plant.
Subclass:
13
This subclass is indented under the class definition.
Systems combining means for generating heat at one place and
distributing it to other buildings, including mains or
conduits having no other apparent use than with these
systems.
SEE OR SEARCH CLASS:
137, Fluid Handling, for fluid distributing and handling
systems not otherwise provided for, see particularly subclass
236.1 for fluid distributing systems including geos:graphic
features and subclasses 356+ for such systems having as a
support a structural member immovably joined to the ground.
138, Pipes and Tubular Conduits, for conduits and underground
ways adapted for use in heating plants and otherwise.
Subclass:
14
This subclass is indented under the class definition.
Heating systems peculiarly adapted for subclasses 302+ and
311+ incubators and brooders.
SEE OR SEARCH THIS CLASS, SUBCLASS:
3 for automatic control.
SEE OR SEARCH CLASS:
119, Animal Husbandry, for specific brooder and incubator
structure combined with the heating means.
122, Liquid Heaters and Vaporizers, for structure of a closed
water heater.
126, Stoves and Furnaces, for structure of air heaters and
stoves.
236, Automatic Temperature and Humidity Regulation, for
automatic control
Subclass:
15
This subclass is indented under subclass 14. Systems in
which the heating medium is water.
SEE OR SEARCH THIS CLASS, SUBCLASS:
4 for automatic control
SEE OR SEARCH CLASS:
236, Automatic Temperature and Humidity Regulation, for
automatic control, per se.
Subclass:
16
This subclass is indented under the class definition.
Heating systems comprising steam or water radiators combined
with a boiler in a unitary structure.
SEE OR SEARCH THIS CLASS, SUBCLASS:
7 for automatic control.
SEE OR SEARCH CLASS:
122, Liquid Heaters and Vaporizers, for a boiler that may
include a heat system for other than heating an enclosure,
subclass 13.3 for a stand boiler (e.g., water heater, etc.)
having a delivery means to dispense a feature (e.g., faucet,
shower, washing machine, dishwasher, etc.).
219, Electric Heating, for electrically heated radiators.
236, Automatic Temperature and Humidity Regulation, for
automatic control.
Subclass:
17
This subclass is indented under subclass 16. Combined
radiators and boilers heated by combustion of fluid fuel.
Subclass:
18
This subclass is indented under subclass 16. Combined
radiators and boilers heated by combustion of solid fuel.
Subclass:
19
This subclass is indented under the class definition.
Heating systems having means for heating the fluid used in
the system and also for additional volume of water.
SEE OR SEARCH CLASS:
122, Liquid Heaters and Vaporizers, subclass 20, for
subsidiary boilers.
126, Stoves and Furnaces, subclass 5 for a steam or hot
water generator for house heating, power, or cooking;
subclasses 350.1-350.2 for a fluid fuel burner other than a
top-accessible liquid heating vessel; subclasses 367.1 and
368.1 for a solid fuel burner submerged underneath the
surface of the liquid that may be held in an open-top vessel,
or subclasses 513 and 514 for a fireplace or accessory having
a liquid heater.
Subclass:
28
This subclass is indented under the class definition.
Heating systems specialized for a vehicle.
SEE OR SEARCH CLASS:
126, Stoves and Furnaces, subclass 56 and 57 for car
stoves.
169, Fire Extinguishers, subclass 55 for fire extinguishers
associated with car heaters.
219, Electric Heating, for systems including electric
heaters.
Subclass:
29
This subclass is indented under subclass 28. Vehicle-heating
systems comprising stoves combined with vehicle structure.
SEE OR SEARCH CLASS:
126, Stoves and Furnaces, for stove structures, especially
subclass 56 and 57.
Subclass:
30
This subclass is indented under subclass 29. Vehicle-heating
stoves having a casing for heating the air.
SEE OR SEARCH CLASS:
126, Stoves and Furnaces, 67 for hot air stoves, per se.
Subclass:
31
This subclass is indented under subclass 29. Vehicle-heating
systems comprising a stove depending from the vehicle.
SEE OR SEARCH CLASS:
126, Stoves and Furnaces, subclass 56 for car stoves.
Subclass:
32
This subclass is indented under subclass 28. Vehicle-heating
systems utilizing a fluid-fuel burning apparatus.
SEE OR SEARCH CLASS:
126, Stoves and Furnaces, appropriate subclasses, for heater,
per se.
Subclass:
33
This subclass is indented under subclass 32. Vehicle-heating
systems with a radiator through which the products of
combustion pass.
SEE OR SEARCH CLASS:
126, Stoves and Furnaces, subclass 91 for heater.
Subclass:
34
This subclass is indented under subclass 28. Vehicle-heating
systems utilizing a hot water circulating system.
SEE OR SEARCH THIS CLASS, SUBCLASS:
12.4 for car heater combined with power plants.
Subclass:
35
This subclass is indented under subclass 34. Vehicle-heating
systems having a boiler located on the vehicle and piping for
heating and circulating water.
Subclass:
36
This subclass is indented under subclass 35. Subject matter
in which the boiler is heated by fluid fuel.
SEE OR SEARCH CLASS:
122, Liquid Heaters and Vaporizers, for boilers, per se.
Subclass:
37
This subclass is indented under subclass 35. Subject matter
with additional means for heating the water by steam from the
train pipe.
Subclass:
38
This subclass is indented under subclass 37. Subject matter
having means for injecting steam from the train pipe into the
water circuit.
Subclass:
39
This subclass is indented under subclass 34. Subject matter
having means for heating the water circuit by steam from the
train pipe.
Subclass:
40
This subclass is indented under subclass 28. Heating systems
utilizing steam radiators.
SEE OR SEARCH THIS CLASS, SUBCLASS:
6 for automatic control of the system.
Subclass:
41
This subclass is indented under subclass 40. Steam heating
systems in which the steam is formed in a boiler on the car.
Subclass:
42
This subclass is indented under subclass 41. Subject matter
having also means whereby steam may be admitted to the
radiators from the train pipe.
Subclass:
43
This subclass is indented under subclass 28. Heating systems
in which the floor is heated from beneath, as by steam, hot
water, or hot air circulation.
SEE OR SEARCH THIS CLASS, SUBCLASS:
69 for means for heating floors of other than vehicles.
Subclass:
44
This subclass is indented under subclass 28. Heating systems
comprising apparatus for storing heat on the vehicle by heat
absorbing bodies.
SEE OR SEARCH THIS CLASS, SUBCLASS:
45 for incased radiators.
75 for heat accumulators, per se.
Subclass:
45
This subclass is indented under subclass 28. Heating systems
comprising radiators in casings, through which air may pass.
SEE OR SEARCH CLASS:
392, Electric Heating, 407 for electrically heated radiators
including heat, storage or transfer means.
Subclass:
46
This subclass is indented under the class definition.
Heating systems for rooms, chambers, or other enclosures
provided with means for removing air from the rooms.
(1) Note. Apparatus for only admitting fresh air and heating
it are not included.
SEE OR SEARCH CLASS:
126, Stoves and Furnaces, subclass 84 for combined stove and
ventilator, and subclass 293 for combined damper and
ventilator.
165, Heat Exchange, 248 for the automatic control of
ventilation in a heating and cooling system; subclass 54 for
heat exchanger installed in a wall traversing passage; and
subclass 59 for a heating and cooling system with a
ventilation feature.
454, Ventilating, for specific ventilating apparatus combined
with an undefined heater.
Subclass:
47
This subclass is indented under subclass 46. Ventilating
heating-systems having a stove as a heater.
SEE OR SEARCH CLASS:
126, Stoves and Furnaces, subclass 80, 84, 216, and 293, for
stove and ventilator combinations.
454, Ventilation, subclass 43 for flue heated ventilators.
Subclass:
48
This subclass is indented under subclass 46. Ventilating
heating-apparatus having a hot-air furnace as a heater.
Subclass:
49
This subclass is indented under subclass 46. Ventilating
heating apparatus having radiators enclosed in an air flue.
SEE OR SEARCH THIS CLASS, SUBCLASS:
45 for similar devices on vehicles.
79 for radiator shields.
Subclass:
50
This subclass is indented under the class definition.
Heating systems in which air is heated directly by a
combustion apparatus and distributed.
SEE OR SEARCH CLASS:
126, Stoves and Furnaces, for structure of heater.
Subclass:
52
This subclass is indented under subclass 50. Air
heating-systems having a stove as the source of heat.
SEE OR SEARCH THIS CLASS, SUBCLASS:
29 for similar devices on vehicles.
47 for ventilating heating systems using a stove.
Subclass:
53
This subclass is indented under subclass 50. Air
heating-systems having a hot-air furnace as the source of
heat.
SEE OR SEARCH THIS CLASS, SUBCLASS:
48 for ventilating heating systems using a furnace.
Subclass:
54
This subclass is indented under subclass 50. Air
heating-systems having a drum in an upper room of the
building, through which products of combustion pass.
Subclass:
55
This subclass is indented under subclass 50. Air
heating-systems ... in which the air is heated in a smoke
flue.
SEE OR SEARCH CLASS:
126, Stoves and Furnaces, 523 for fireplace-type heater.
Subclass:
56
This subclass is indented under the class definition.
Heating system in which the room or building is heated by the
circulation of water or some other liquid.
SEE OR SEARCH THIS CLASS, SUBCLASS:
8 for automatic control.
12.4 for car heaters.
15 for brooder heaters.
17,18, for combined radiator and boiler.
34 for vehicle heaters.
Subclass:
57
This subclass is indented under subclass 56. Water
heating-systems in which the water is heated by fluid fuel.
Subclass:
58
This subclass is indented under subclass 56. Water
heating-systems where the water is heated by steam.
SEE OR SEARCH THIS CLASS, SUBCLASS:
37 for train steam heaters.
71 for steam radiators.
Subclass:
59
This subclass is indented under subclass 56. Water heating
systems having special means for circulating the heating
liquid.
SEE OR SEARCH CLASS:
138, Pipes and Tubular Conduits, 37 for fittings and pipes
of general utility having means therein to direct the flow of
fluid therein and even though intended to be used in a
heating system.
Subclass:
60
This subclass is indented under subclass 59. Subject matter
in which the water is heated and forced out of a boiler by
intermittent pulsations.
Subclass:
61
This subclass is indented under subclass 59. Subject matter
having an auxiliary boiler for aiding the circulation.
SEE OR SEARCH THIS CLASS, SUBCLASS:
37 for train steam boiler combinations.
Subclass:
62
This subclass is indented under subclass 59. Subject matter
in which only a part of the water is bypassed through a
boiler.
Subclass:
63
This subclass is indented under subclass 59. Subject matter
having a pump for circulating the water.
Subclass:
64
This subclass is indented under subclass 63. Subject matter
wherein the pump consists of a chamber where water enters and
is forced out by means of steam pressure.
Subclass:
65
This subclass is indented under subclass 56. Water
heating-systems with means for regulating or varying the
pressure on the circulating system.
SEE OR SEARCH CLASS:
137, Fluid Handling, 455 for line condition change
responsive valves, particularly subclasses 505+ for fluid
pressure regulators, per se.
236, Automatic Temperature and Humidity Regulation,
appropriate subclasses.
Subclass:
66
This subclass is indented under subclass 56. Tanks or
chambers limited in use to provide for the expansion of the
water in the circulating pipes and radiators of water heating
systems.
SEE OR SEARCH CLASS:
137, Fluid Handling, appropriate subclasses for fluid
handling apparatus including tanks in combination with other
fluid handling means, see particularly subclass 593 for such
systems including an expansion chamber in combination.
220, Receptacles, for tank structure not necessarily limited
to water heating systems.
Subclass:
67
This subclass is indented under the class definition.
Systems for heating buildings, rooms, or chambers by means of
steam circulating through conduits or passing through
radiators.
SEE OR SEARCH THIS CLASS, SUBCLASS:
6 for automatic control of car heating.
9 for automatic control.
12.8 for car heating.
40 for vehicle heaters.
SEE OR SEARCH CLASS:
34, Drying and Gas or Vapor Contact With Solids, subclass 119
and 124 for heaters for dryers.
Subclass:
68
This subclass is indented under subclass 67. Steam heating
systems with special means for removing the incondensable
gases in the system.
SEE OR SEARCH CLASS:
137, Fluid Handling, 197 for discriminating outlets for gas
(gas vents which do not pass liquid).
236, Automatic Temperature and Humidity Regulation, for
thermal valves.
417, Pumps, for pumps, per se.
Subclass:
69
This subclass is indented under the class definition.
Heating systems in which the room is heated by heated fluid
circulated within or beneath or caused to contact with the
underside of a floor.
SEE OR SEARCH THIS CLASS, SUBCLASS:
43 for the heating of vehicle floors.
SEE OR SEARCH CLASS:
454, Ventilation, 185 for hollow walls and floors having
vents for passage of air.
Subclass:
70
This subclass is indented under the class definition. Hollow
bodies of considerable surface area peculiarly adapted to
have a heating fluid passed through it and to radiate heat
from the surface. Radiators must be absolutely limited to
heating purposes by radiation in order to fall within this
subclass and those indented thereunder.
SEE OR SEARCH CLASS:
165, Heat Exchange, 128 for a heat exchanger having
vertically extending flues for producing a thermosyphonic
flow of fluid not having features specializing it to use in
heating air within a chamber; subclasses 168+ for a panel
with conducting passages for a heat exchange fluid; and
subclasses 172+ for an assembly of tubes for transferring
heat.
Subclass:
71
This subclass is indented under subclass 70. Radiators
adapted to contain water heated by steam.
SEE OR SEARCH THIS CLASS, SUBCLASS:
75 for steam heat accumulator.
Subclass:
72
This subclass is indented under subclass 71. Radiators
containing water heated by steam either injected into the
water or heated by steam passing through conduits that heat
the water, the steam finally coming into contact with the
water in the radiator. These radiators may also be
convertible as steam radiators or water radiators heated by
steam.
SEE OR SEARCH THIS CLASS, SUBCLASS:
74 for injecting means for steam circuits.
Subclass:
73
This subclass is indented under subclass 70. Radiators
limited to the use of steam as a heating fluid and incapable
of being used as a condenser for steam.
SEE OR SEARCH THIS CLASS, SUBCLASS:
40 for steam heaters for vehicles.
Subclass:
74
This subclass is indented under subclass 73. Steam-heated
radiators having injecting means for causing a continued
circulation of steam through or around within the radiator or
for injecting air into the radiator or for circulating water
therein.
SEE OR SEARCH THIS CLASS, SUBCLASS:
72 for means to inject steam into the water.
Subclass:
75
This subclass is indented under subclass 73. Steam-heated
radiators having either a liquid or solid therein which
absorb heat from the steam, stores it therein, and radiates
the heat after the steam is turned off.
SEE OR SEARCH THIS CLASS, SUBCLASS:
44 for systems having heat accumulators on vehicles.
69 for floor heaters.
76 for ceramic radiators.
Subclass:
76
This subclass is indented under subclass 70. Radiators made
in whole or in part of ceramic material (earthy plastic) or
natural stone.
SEE OR SEARCH THIS CLASS, SUBCLASS:
69 for floor-type heating systems.
Subclass:
77
This subclass is indented under subclass 70. Radiators with
special features for warming the feet.
SEE OR SEARCH CLASS:
126, Stoves and Furnaces, 204 for other body warmers.
248, Supports, 205.1 for a non-heated footrest having
general utility.
297, Chairs and Seats, 423.1 for a nonheated footrest.
Subclass:
78
This subclass is indented under subclass 70. Radiators
combined with means for moistening the air or air moistening
apparatus necessitating its application to a radiator when in
use.
SEE OR SEARCH CLASS:
236, Automatic Temperature and Humidity Regulation, 12.1 for
fluid mixers and 44, for humidity control.
261, Gas and Liquid Contact Apparatus, appropriate subclasses
for contact structure.
454, Ventilation, subclass 110, 157, 223, 291, 328, and 337
for ventilators having liquid contact devices.
Subclass:
79
This subclass is indented under subclass 70. Heat shields
applied to radiators or air directors combined with dust
guards.
SEE OR SEARCH CLASS:
148, Metal Treatment, 640 for processes which utilize a
protective or insulating shield of metal from heat in a
method of treating solid or semi-solid metal to modify or
maintain the internal physical structure (i.e.,
microstructure) or chemical property of metal.
165, Heat Exchange, subclass 55 for a wall mounted heat
exchanger with a projecting shield; subclass 129 for a heat
exchanger equally adapted for conducting heating or cooling
fluid arranged with a distinct flue forming enclosure; and
subclass 134 for a heat exchanger with a protector.
454, Ventilation, 245 and 284+ for floor and wall
registers.
Subclass:
80
This subclass is indented under the class definition.
Devices for preventing freezing in heating conduits or other
hollow heaters or for thawing out heating conduits not
provided for in other classes.
SEE OR SEARCH CLASS:
137, Fluid Handling, for fluid handling systems including
means to prevent freezing see particularly 59, 301+ and 375.
138, Pipes and Tubular Conduits, 32 for antifreezing devices
for pipes of general utility, though intended to be used in a
heating system.
428, Stock Material or Miscellaneous Articles, appropriate
subclasses, for a stock material product in the form of a
single or plural layer web or sheet, and especially 304.4
for such a product embodying a component which is porous or
cellular.
Subclass:
81
This subclass is indented under the class definition.
Processes for heating houses, rooms, or other enclosures,
except processes involving automatic control.
SEE OR SEARCH THIS CLASS, SUBCLASS:
12 for processes including automatic control.
Information Products Division -- Contacts
Questions regarding this report should be directed to:
U.S. Patent and Trademark Office
Information Products Division
PK3- Suite 441
Washington, DC 20231
tel: (703) 306-2600
FAX: (703) 306-2737
email: oeip@uspto.gov
Last Modified: 6 October 2000