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PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER ; FEED-WATER SUPPLY ; CONTROLLING WATER LEVEL ; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN BOILERS (chemical treatment of water, e.g. purification, C02F ; enclosed heat-exchange apparatus in general F28D ; controlling in general G05)
Definition statement
This subclass covers:

This subclass covers general aspects of, or methods for, preheating or accumulating feed water. All devices in a power plant or a steam boiler for heating water in liquid form, like economisers or water preheaters and accumulating water for preheating purposes, controlling and regulating the water level in said water accumulators, feed-water supply like automatic water feeding and controlling methods are covered. Furthermore safety feed water supply and arrangements of feed water pumps are also covered.

Relationship between large subject matter areas

Water heaters in general are classified in F24H. Generation of steam or vapour is classified in F22B, devices and methods for superheating steam in F22G. Steam engine plants where engine aspects predominate are classified in F01K, domestic central heating systems using steam are classified in F24D, heat exchange or heat transfer in general is classified in F28.

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

Cooking vessels

Apparatus for making beverages

Baking, Roasting, Grilling, Frying

Machines for cleaning floors, carpets, furniture, walls, or wall coverings with arrangements for steam generation

Water heater arrangements for cleaning windows

Bathing devices for special therapeutic or hygienic purposes

Degasification of liquids or water

Cleaning by methods involving the use or presence of liquid steam

Treatment of water, waste water, or sewage

Washing machines with steam generation

Hand irons

Use of steam extracted from the engine for feed-water purposes

Use of two or more feed-water heaters in series

Use of desuperheaters for feed water heating

Water heaters for domestic or space-heating systems

Water heaters heated by electric, magnetic or electromagnetic fields

Glossary of terms
In this subclass, the following terms (or expressions) are used with the meaning indicated:

Economiser

heat exchanger for heating feed water normally beyond the boiling point improving the boiler's efficiency

Feed-water heaters, i.e. economisers or like preheaters
Definition statement
This group covers:

General aspects and constructional features of devices or heat exchangers for heating water normally beyond the boiling point in order to improve the boiler's efficiency arranged in a flow path up stream of an evaporator. This group covers also economisers and preheaters with water tube arranged in the boiler furnace, in fire tubes or in flue ways, with water tubes arranged outside the boiler furnace and heated for example in a separate heat exchanger. Furthermore also water and air preheating systems, combinations of exhaust-steam and smoke-gas water preheater and preheaters incorporating thermal de-aeration are covered.

Relationship between large subject matter areas

Heat exchangers and types thereof are classified in F28C and F28D, details of heat-exchange and heat-transfer apparatus are classified in F28F.

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

Safety devices for boilers in general

Control of feed-water heaters

Thermal de-aeration of water per se

Liebig degassing water

Hollow fire-bars, grates, or the like used as water tubes

Valves for venting

Heat exchange apparatus in boiler for heating air supplied for combustion

Glossary of terms
In this group, the following terms (or expressions) are used with the meaning indicated:

Economiser

feed water heater

Accumulators for preheated water
Definition statement
This group covers:

Accumulators and storage vessels for water which is heated in an economiser arranged within the combustion chamber or combined with steam accumulators and thereby heated by steam or connected directly to boilers by water conduits. Water accumulators with preheated water specially adapted for locomotives and control devices are also covered by this group.

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

Plants characterised by the use of steam or heat accumulators

Vehicles being a steam locomotive

Steam boilers of fire-box type, locomotive boilers

Control of feed water heaters; water-level and feeding

Controlling water feed or water level; Automatic water feeding or water-level regulators (steam traps F16T; measuring or indicating instruments G01; for indicating water level G01F; level control in general G05D 9/00)
Definition statement
This group covers:

Devices and methods for controlling the supply of feed water and the feed water level using intermediate compartments, pivoting buckets, receptacles outside of the boiler and devices with float actuated valves, responsive to thermal expansion and contraction, with electric switches. Also regulators with varying the speed or delivery pressure of feed pumps and automatic feed-control systems are covered by said group.

Relationship between large subject matter areas

Documents concerning measuring volume, volume flow, mass flow or liquid level are classified in G01F and documents concerning level control in general in G05D 9/00.

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

Steam traps

Measuring or indicating instruments

For indicating water level

Level control in general

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

Control devices of plants characterised by condensers

Control system for two or more steam generators including feeding

Applications and arrangements of alarm or automatic safety devices for steam boilers

Control devices for feed water heaters with water tubes arranged in the boiler furnace

Arrangements of feed water pumps

Auxiliary devices for promoting water circulation (adaptation of boilers for promoting water circulation F22B 37/34)
Definition statement
This group covers:

Devices in for promoting or enhancing water circulation like saddles, deflecting plates, Venturi arrangements, injectors for water or steam, rotary devices like for example pumps, said devices also specially adapted for locomotive boilers. Control devises of said devices are also covered by said group.

Relationship between large subject matter areas

Pumps in general are classified in F04B, F04C, F04D and F04F

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

Adaptation of boilers for promoting water circulation

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

Vehicles being a steam locomotive

Control devices for feed water heaters with water tubes arranged in the boiler furnace

Feed-water supply not provided for in other main groups
Definition statement
This group covers:

All other aspects of feed water supply, which are not covered by the other main groups, like for example emergency feed water supply, arrangements of feed water cleaning, when the water is cleaned between condenser and boiler and arrangements of feed water pumps

Relationship between large subject matter areas

Pumps in general are classified in F04B, F04C, F04D and F04F

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

Applications and arrangements of alarm or automatic safety devices for steam boilers

Water and air preheating systems

Feed water heater with direct heat transfer like mixing water with steam

Auxiliary devices or apparatus for promoting water circulation

Arrangements or modifications of condensate or air pumps

Treating live steam, other than thermo-dynamically, cleaning and filtering

Regenerating steam by compression done by an injection apparatus

Special rules of classification within this group

Only feed water supply devices and methods for which there is no entry in the main group F22D 7/00 are to be classified in F22D 11/00.

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Last Modified: 10/11/2013