ORDER

S.L. Peeran, Member (J)

1. The appellants are aggrieved with the order issued on 16-4-1990 passed by the learned Collector of Customs (Appeals), Bombay.

2. The appellants have claimed the benefit of the Notification No. 242/76-Cus., in respect of the imported item described in the Bill of Entry as Electric Cast Refractories with Zinconia content 40% and above (Refracting bricks of special shape for use as component parts of Glass furnace). The Assistant Collector has taken a view that as per ISI definition 9.32 IS-4041-1967 "A Regenerator is a periodic heat exchanger which alternatively receives heat from combustion products and gives up heat to incoming air or gas" and, therefore, he has held that the regenerator works is a periodic heat exchanger and as such, does not form an essential part of the Industrial Furnaces where glass is actually melted and the temperature is always higher than 1550°C. He has further held that the Refractory bricks imported are to be used in front wall of the Regenerator where normal temperature would be around 1400°C and hence the benefit under Notification No. 242/76-Cus. would not be available to the item in question. The learned Collector (Appeals) has held as follows :

"I have gone through the written and oral submissions and also the Glossary of Terms relating to Refractory materials as appearing in the Handbook No. IS-4041-1987 by the ISI and the following are the definitions which are relevant for examining the merits of the appeal -

9.30 Port - Furnace opening through which liquid for gaseous fuel or air or both for combustion is introduced.

9.31 Recuperator - A continuous heat exchanger in which heat from combustion products is transferred to incoming air or gas through metal or refractory walls.

9.32 Regenerator - A periodic heat exchanger which alternatively, receives heat from combustion products and gives up heat to incoming air or gas.

9.44 The bottom of a door opening in a furnace.

23.1 Back wall, End wall or Cable wall - The wall at the charging end of tank furnace.

23.2 Bottom - The floor of a tank furnace, including the surface which comes into contact with the glass.

23.11 Crown - The roof of a tank furnace.

In the Customs Tariff Industrial Furnaces are covered under Heading 8417 and in the Explanatory Notes Non-Electrical Industrial Furnace have been defined as those in which heat is produced in chambers at high temperatures by the combustion of fuel either directly in the chamber or in separate combustion chambers. They are used in the heat treatment i.e. by roasting, fusion, calcination, etc. of various kinds of products which may be placed on the fire bed, crucibles etc. ISI Para 23 includes the terms relating to the glass industry and the parts of the furnace have been shown as : (23.7) leading from the refining zone to the drawing chambers.

Conditioning zone (23.8) - The part of a tank furnace for flat glass in which the conditioning of the glass is completed before it passes to the forehearth or drawing chamber.

Doghouse (23.15) - A refractory shape with a slot, depressed below the surface of the glass and used for the upward drawing of sheet glass in the Fourcault process... and which has a small extension of a tank furnace into the batch is fed.

Drawing chamber (23.17) - i.e. from where the sheet is drawn.

Flue line block (23.26) - A block forming part of the upper course of walls of tank furnace, when these are constructed with more than one course.

Fore-Hearth (23.27) - The part of extension of a tank furnace from which glass is taken for forming.

Melting End (23.33) - The part of a tank furnace where melting and refining are carried out.

Refining Zone (23.41) - The part of a tank furnace where the glass becomes largely free from seed and bubbles.

Skimming Block (23.49) - A small extension on the sides of a tank furnace for melting flat glass by means of which surface impurities are removed, usually positioned just before the floaters.

Tank Block (23.54) - A block used in the construction of the lower parts of the wall of a tank furnace.

Working End (23.61) - The term refers to either of the following -

(a) the compartment of a tank furnace for container glass following the melting end and separated from it by the bridge, or

(b) the end of a glass tank furnace without a bridge from which the glass is withdrawn ...

Apart from this, the various walls also constitute parts of the furnace. Now in the definition of a regenerator (9.32) as shown above, the same has not been defined as a part of the tank furnace on the same lines as the other parts enumerated above. Now in the ISI Book, page 67, two cross section views of the tank furnace have been given i.e. (1) when it is viewed from above (Vertical top) and the other when it is viewed sideways (horizontal). In the vertical view the double lines show the equipment sections outside the furnace lines. The various zonal and parts of the tank furnace included therein are 23.15, 23.33, 23.49, 23.8, 9.44, 23.17 and 23.7. The double line separates the regenerator from the tank furnace and this shows that the regenerator is not treated as a part of the furnace. The fuel mixture after combustion is drawn into the regenerator through ports so as to take out the heat energy and transfer it to the fresh mixture of fuel and air and to preheat it to a temperature of 1175°C. A furnace is essentially an equipment in which the combustion of fuel takes place so as to generate heat for melting etc. as mentioned in the Explanatory notes. At the most, a furnace may have various sections, one in which refining takes place, one from where the raw material is fed, the other from where the finished product i.e. sheet glass etc. is drawn out etc. But in a regenerator no such combustion takes place and it is essentially a heat exchanger which transfers the heat from the combustion products to the incoming fuel mixture. No doubt, it is essential for the efficient functioning of a tank furnace since it conserves the heat energy and reduces the requirement of the fuel for combustion and even the tank furnace may be so designed that it can work only with the regenerators but that by itself will not entitle the regenerator to be classified as an integral part of the furnace. Accordingly the refractory bricks used in the regenerator will not qualify for the benefit of Notification No. 242/76. The appeal is accordingly rejected."

3. We have heard Shri J.C. Patel, learned Advocate for the appellants and Shri J.N. Nair, learned DR for the Revenue; Shri Patel heavily relied on ISI - 4041-1987; technical literature, Product literature and extracts from the Book "The Handbook of Glass Manufacture Vol. I by Dr. Fay V Tooley, published by Books for Industry Inc. New York and the figures/sketches appearing in the book and argued that the port and regenerator are part of general furnace design and as such, the 'Refractory bricks' which make up the 'Regenerator' and 'port' are clearly for use as component parts of the furnace. He contended that the learned Collector had erred in holding that 'Regenerator' is not a part of the Glass Tank Furnace and the learned Collector had drawn wrong presumption of sub Sl. No. 9.32 of IS Glossary of Terms; and that the learned Collector had chosen to disregard the caption 'Terms relating to General Furnace, Design of Sl. No. 9 under which the 'Regenerator' has been defined and Port in SS No. 9.30. The 'Refractory bricks' which make up the Regenerator and port are clearly for use as component parts of the furnace. As both the Regenerator and Port are shown in the figures 34 and 36 of the Glass Tank Furnace, they would necessarily become part of the Furnace.

The furnace had been compositely designed alongwith regenerator and port and if one of them requires replacement or repair, the furnace would have to be necessarily shut down. They perform integrated function and hence cannot be considered as separate. The learned Collector having given the finding that the Regenerator is essential for the functioning of the Tank furnace and although such furnace is so designed that it cannot work without the Regenerator yet to hold that it is not a part of the furnace, was therefore, not justified. The imported items are used as component parts of the furnace is clearly evident from' the manufacturers catalogue and, therefore, the denial of the benefit of the notification is not justified.

4. The learned advocate relied on the ruling of the Tribunal in the case of Steel Authority of India v. Collector of Customs as reported in MANU/CE/0463/1988 : 1989 (42) E.L.T. 89. In this case also, the question of classification of specially designed refractory bricks came up for determination. The Bench had held that refractory bricks, not being component parts of industrial furnace, are not entitled to the benefit of the notification. It had been further held that 'teaming ladles' used in the construction of the present refractory bricks of special quality and shape are receptacles for molten steel. It was held that the ladles were not incorporated into, nor are they integrated parts of furnace. The Bench has also concluded that for an article to be called a part of an industrial furnace, it must be something which is incorporated in the construction of the furnace. The learned counsel contended that if this logic was to be accepted, then 'Regenerator' and 'Port' being integral part of the furnace as is evident from the literature, IS Glossary of Terms and Product Catalogue, the ratio would apply squarely to the facts of the present case.

5. Shri Nair, learned DR submitted that as per the definition of the term 'Furnace', and 'Heat Changer', Regenerator appearing in McGraw Hill Encyclopedia of Science and Technology, pages 504, 652 and 1344 respectively, it is clear that Regenerator is a heat exchanger and advised use in furnace to transfer heat from a fluid flowing on one side of a barrier to another fluid (or fluids) flowing on the other side of the barrier. Therefore, they are different and independent devices not performing the work of a furnace nor is a part of furnace. The reading of the explanatory notes under Heading 84.17 of HSN also does not support the appellant's case. The IS Glossary of Terms and literature refers to the general furnace design. Even as for the book relied and material discussed therein, regenerator is not a part of the furnace. Regenerator is a device used alongwith furnace and it is a technological innovation to save heat and economy.

6. Shri Patel in counter reply submitted that he agreed with the learned Departmental representative that heat exchanger is an independent unit. However, it would not be so if they were used integrally alongwith the furnace. The classification of heat exchanger would then be independent in such circumstances. While it would be classifiable separately under heading 'Heat Exchanger', but the same if used as an integrated part of another unit, then it would go with the unit which does the predominant function and in support of his plea, he drew his support from the interpretative rules for classification as well as notes 3 and 4 of Section XVI. The Explanatory notes to Heading 84.14 also stated so and in the ruling of Steel Authority of India (supra) the Bench had discussed it at page 91 of the report. He pointed out from page 417 of the extract of the Book relied to plead if repairs of Regenerator was to be done than the furnace was required to be shut down. The figures, diagrams of furnace would clearly indicate that the Regenerator is an integral part of the furnace. The trade catalogue also support the plea that Regenerator is a zone of furnace.

7. We have carefully considered the submissions made by both the sides and have perused the records. The question that arises for our consideration is as to whether the imported item which is used as replacement part in the Regenerator, would be a part of the furnace. In other words, is the Regenerator installed in the importers' furnace an integral part of the furnace to enable them to claim the benefit of the notification in question? The lower authorities have denied the exemption on the ground that the Regenerator is an independent unit and cannot be considered as an integral part of the furnace and, therefore, the imported refractory bricks which are going to be used in the refractors cannot be deemed to be used as part of furnace. The reasoning of the learned Collector has already been extracted above. Is this finding sustainable in the light of the finding given by the Tribunal in the case of Steel Authority of India (supra)? The question that came up for consideration in that case is the use of refractory bricks specially designed for use for construction of teaming laddie of open health furnace. The Bench while discussing the issue, has held in para 8 as follows -

"We have carefully considered the submissions of both sides. This Tribunal has consistently taken the view that while CCCN Explanatory Notes have no binding force, they have considerable persuasive value in ascertaining the scope and coverage of entries in the Customs Tariff Schedule since the Indian Customs Tariff Schedule is patterned on the CCCN.

It is clear that for an article to be called a part of an industrial furnace it must be something which is incorporated in the construction of the furnace. This is what the Explanatory Notes under Heading 84.14 of the CCCN also implies when it states that -

"Many industrial furnaces and ovens incorporate equipment for charging or discharging, for manipulating the doors, covers, hearths or other moving parts, or for tilting the furnace etc. Such lifting or handling equipment is to be classified with the furnace or oven provided that it forms integral part thereof; otherwise it is to be classified in heading 84.22"

(Emphasis added)"

It is not in dispute that the teeming ladles using in their construction the present refractory bricks of special quality and shape are receptacles for molten steel. They are not incorporated into, nor are they integral parts of furnaces. This is also clear from pages 181-182 of the book "Materials and Technology" by JH DE Bussy which states that -

"All crude steel is poured into ladles. These are refractory-lined steel buckets that range in capacity from amount a hundred weight (about 50 kg) to a hundred or more tones. They are brought along on overhead cranes. The smallest can be tipped over to pour their contents into whatever receptacle is waiting, but the common practice is to have a stopper in the bottom, and this can be removed by a hinged and levered device to allow metal to flow out of the bottom.

If the steel is further to be refined the ladle may go directly to a refining unit for stream or ladle degassing. Otherwise the molten metal is transferred (poured or teemed) to moulds in which it solidifies to make ingots, which can also range from a few hundred weights to many tons in weight. The steel ingot is the crude material for further treatment.

The refractory bricks cannot therefore be considered as component parts of industrial furnaces."

So it follows that what has to be considered in the light of the above ruling is as to whether Regenerator, to which this imported items are being used as replacement parts, is an integral part of the furnace. Let us examine the evidence placed before us to answer this point.

8. The importers in their annexure to their letter dated 8-1-1990 to the Assistant Collector of Central Excise, Appraising Department, Group III, Bombay, have stated that -

"Ours will be a end fired regenerative glass melting industrial furnace which will be used for melting (pressed ware) glass. This furnace will be 'Natural gas' fuel fired with regenerative heat recovery system. Furnace shall be with high fuel efficient regenerators which will save around 40% min. of fuel compared to conventional furnaces."

They have given two diagrams of their furnace which shows the location of port and Regenerator. The working of the Furnace has been given as follows -

"Raw materials of the mixed glass batch is fed from the dog house located on R.H. side of the melting tank with the help of batch charger. Mixed batch contents are quartx sand, feldspar, lime powder, Dolomite, soda ash and Barytes and glass cullet. Batch moves from dog house to the throat side. Burners are located under the port which maintains 1500 to 1550°C temperature inside the melter depending upon the glass dew to get complete seed free glass required for pressed shape and covers the complete entire cross section and full length of melting tank. The melted glass passes through the throat and reaches to the working end which has five different zones having gas burners located in super structure to maintain glass homogeneity and conditioning of glass temperature based on different drew on each forehearths. Combustion system and heat regeneration is a cyclic operation which will be altered time base and temperature base whichever earlier occurs. Let L.H. side 3 Nos. burners are in operation. Fuel gases will enter R.H. side part and flue duct and goes to R.H. side regenerator chamber and finally exhausted to chimney. When these flue gases passes through R.H. side regenerator chamber where high heat conductive type refractories are stored which will absorb heat from the flue gas. At the same time combustion air will be fed near the all reversal damper which enters to the outlet of second pass. L.H. regenerator chamber and than to first pass to melting tank through L.H. port and mixes with natural gas for combustion. During this process room temperature combustion air will absorb heat from the previously heated L.H. side regenerator chamber. The same cycle will be altered time base and temperature base L.H. to R.H. side and so on. In this process, combustion air gets heated to 1175°C and mixes with the natural gas for combustion. Thus the fuel consumption becomes most efficient due to the preheat of the air with the help of flue gases.

When these flue gases travel from melting tank port with high velocity which carries batch carry over to the regenerators. The regenerator target and middle wall made of electrocast has to face flame impingement temperature around 1400°C and glass batch carry over effect. Combustion air temperature will be 1175°C. The furnace life will be 5 to 6 years but in order to match the regenerator life of 5 to 6 years at 1400°C operating temperature and since the target wall, middle wall which are highly intensive zone for temperature and against corrosion. So we have selected this target and middle (partly height of full length of regenerator) wall of electrocast refractory. The remaining refractory will be indigeneously selected based on different temperature gradient and thermal shock, cold crushing strength requirement."

9. At page 504 of McGraw Hill Encyclopedia of Science and Technology, appears a note on 'Heat Exchanger'. A few paras of the said notes are extracted below -

"A device used to transfer heat from a fluid flowing on one side of a barrier to another fluid (or flowing on the other side of the barrier).

When used to accomplish simultaneous transfer and mass transfer, heat exchangers become special equipment types, often knows the other names. When fired directly by a combustion process, they become furnaces, boilers, heaters, tube-still heaters and engines. If there is a change in phase in one of the flowing fluids - condensation of steam to water for example - the equipment may be called a chiller, evaporator, subliment distillation-column reboilers, still, condenser or cooler-condenser.

Heat exchangers may be so designed that chemical reactions or energy generation processes can be carried out within them. The exchanger becomes an integral part of the reaction system and may be known, for example, as a nuclear reactor catalytic reactor, or polymerizer.

Heat exchangers are normally used only for the transfer and useful elimination or recovery of without an accompanying phase change. The fluids on either side of the barrier are usually liquids, but they may also be gases such as stream air, or hydrocarbon vapours, or they may be metals such as sodium or mercury. Fused salts are also used as heat exchanger fluids in some applications."

10. A few paragraphs referred from 'The Handbook of Glass Manufacture, Vol. I by Dr. Fay V. Toolay published by Books for Industry INC, New York is also referred below -

"In this Sub-section regenerative furnaces are discussed. Design features are discussed in Sub-sections 2 and 3. Unit melters and recuperative furnaces are described in Sub-section 7.

A Glass Container, Side Port Type

A typical tank (furnace) of the side port type is shown in Figure 1 in cross-sectional elevation; and in Figure 2 in longitudinal, cross-sectional elevation.

This has the simple box-type regenerators. In older models the crown of the regenerator chamber is positioned below the level of the port floors, and a port uptake connects each port to the regenerator thru the regenerator crown. The advantage of the box type is that it allows more checkers to be set in the regenerator chamber and it has a simpler roof (crown) construction. The regenerator crown, in other words, is out of the part of the flame, whereas in the older uptake construction the roof and sides and end wall of each port uptake are subjected to a beating. The edge of the opening into the regenerator crown in the uptake construction, being face by the flame, also was a weak spot.

In operation the upcoming heated air for combustion meets the fuel in the port and the flame burns over the surface of the glass, within the space under the melter crown; and leaves by the port opposite going down thru the checker setting on that side and out thru the reversing valve to the exhaust stack. Every 20 minutes, or 30 minutes, depending on the specific furnace, the part is reversed. The combustion air then comes up thru the opposite checker which is now hot, and the flame traverses the melter in the opposite direction. In other words, exhaust heat is stored in the checker settings, which allows a greater efficiency and a higher flame temperature than could otherwise be the case with cold air.

The highest temperature in the melter ranges from about 2850 to 2920°F. Usually, the safe limit is determined by the particular glass and the softening point of the silica crown (roof) which softens and drips starting at 2950°F. The reason for always using silica in the roof over the glass rather than some more resistant material is that silica, in addition to being a strong brick at high temperature is one in which the corrosion products are compatible with the glass whereas the other materials are more likely to produce insoluble stones and other inclusions.

In the breast wall and below the glass most of the refractories in use now are heavier than the glass very dense, and resist attack by the molten glass much better than those of quite a few years ago. All refractories in the sides of the melter below the glass need to be force cooled on the side face as their life is short, especially at the glass surface line where the rate of corrosion is greatest. As a furnace...more and more cooling 'wind' is applied at other critical spots as they develop."

At page 279 appears a write up on 'Regenerators'. A few paragraphs are noted below -

"A furnace without adequate regenerator capacity is at a disadvantage from an efficiency standpoint and from a practical operation standpoint in its inability to...at extra high rates of glass pull. Given adequate checker capacity, flue size, and high stack draft, almost any furnace will perform well.

Within the past 20 years or so, an astounding change took place in furnace checkers. Before that time, any theoretical calculations involving heat regeneration would have been well high useless due to the fact that by the time the checker brick setting had gone half way through a campaign, it was so smeared up as to lose any resemblance to the detail it had at the start. Through the employment of basic brick an air checker can live through a campaign of 4 or 5 years and finish in its original condition for all practical purposes. If someone will take the time and collect the data, it is sure that the design of our checkers can be put on a more sound theoretical basis.

However, the checker setting is still the limiting factor in life of a campaign on a furnace, only at a higher level of pulling rate than 20 years ago. At extreme melting rates, for instance of 3 sq. ft./N.T./day the checker can plug up badly in just a few months from the physical carryover of dusty material into them. This dusty material softens into a viscose, tough, corrupted, glassy slag which flows downward in the cells of the checker setting. It eventually seals off the gas flow by bridging across. The zone of plugging begins where it meets a temperature level low enough in the checker to stop the stiff glassy slag from descending further.

Each cell which seals up causes the checker setting around it to cool off that much more and thereby worsens the condition, eventually resulting in a cold, black checker setting in the regin of the carryover, for lack of passage of hot exhaust gas through it. Some improvement can be made by burning gas pipe flames under the checker setting, on the incoming air side, in the space between the rider arches. The extra heat supply causes some of the constructing slag material to come more fluid and drop free onto the floor of the flue, but eventually the freezing and plugging merely descends to a lower level in the setting."

Again at page 406, under the topic "2. Environmental Conditions for Refractories - A General Features of Environment", the following write up is significant.

"Temperature - The glass making process is carried out at rather high temperatures, which vary considerably depending on the type of glass being manufactured and the production demands on a particular unit. Temperatures generally range from about 1800° (982°C) to 3000°F (1649°C) from the very coldest portion of a furnace to the very hottest portion of a high production furnace. It can be stated categorically, that the severity of reactions, between glass or glass vapour or batch solids and refractories increases strongly with temperature. For normal corrosion reactions, it can be stated that this is a logarithmic function. The melting area of the furnace is generally the highest temperature area with a marked decrease in temperature in the feeder channels and other such arrangements leading to forming machines. In the superstructure, areas of the furnace, the same temperature relationships hold. In regenerative chambers, the temperature generally is highest at the top of the checker setting and decreasing going down the setting to the rider arches. However, in this area the temperature varies with reversals and is not nearly so uniform as in the tank superstructure proper and in the melter basis where temperature in regenerative areas is one of the prime conditions dictating refractory selections.

The ideal mode of furnace operation seems to be to distribute the temperature so that in the melting area the backwall temperature is considerably lower than that of the hot spot which is normally about half way down the melting chamber. This thermal curve (i.e. low backwall temperature with respect to hot spot temperature) in the furnace appears to be very important in producing the convection stirring effect, which is in turn quite important in homogenization the glass and refractory products taken into solution by contact corrosion, as well as giving considerable homogenization to any material which may fall into the glass from the above the glass level. Transverse convection currents are also produced in the furnace due to cool side walls, which also aid in the homogenizing effects described above.

There is generally a decrease in temperature with glass depth, and this temperature decrease is more pronounced as the optical transmission of the glass goes down. The magnitude of the temperature decrease with glass depth diminishes as convection stirring effects become more active.

It can also be stated that temperature is generally higher in the superstructure of melter and refiner areas than the glass temperature itself. This fact is important to remember in discussion of thermal situations in glass furnaces. For example some refractory corrosion evaluation methods involve isothermal testing in contact with glass. Testing at temperature equivalent to those reported as maximum in the superstructure (hot spot) might give misleading results. Such measurements are preferably carried out at temperature approximating those obtaining in the glass itself."

At page 417, there is a write up on 'Regenerators' which is also reproduced below -

"(a) General notes. - While it is true that the quality of glass is not usually affected by refractory selection in this area, the economics of glass making are profoundly affected by refractories selections made for regenerator settings and chambers. Often at present, it is deterioration and plugging or collapse in such areas which is shutting down furnaces for repairs while other areas in the furnace for repairs, while other areas in the furnace still have life and would not require repair. At the time of such repairs, often a lot of good refractory is thrown away because it is most economical to repair infrequently and to repair rather large areas simultaneously. Such shutdowns for regenerator repair are always expensive, but especially so if they are unscheduled. Obviously this is one of the areas of the glass furnace requiring some fundamental improvements in materials to balance out life so that every large areas of the furnaces can be repaired simultaneously and on a scheduled basis.

The areas encompassed by this discussion are meant to include all elements of the heat regeneration system proper but excluding the port necks, port crowns, etc. which have been discussed earlier. Some areas of this system i.e. flues, stacks etc. form more or less permanent parts of the glass furnace structure; however, the regenerator chamber proper is subject to periodic replacement and the discussion will be concentrated on materials and practices for these areas.

Walter and Kivala have made an excellent summary of the chief features of the environment affecting refractories for these areas, and the factors affecting the life of materials used. The regenerator chamber and the checker setting do not form a single environment for refractories but a number of conditions varying in severity in various parts of the regenerator. The factors listed by Walter and Kivala are (1) temperature cycling (2) Oxidation/reduction effects (3) solid carryover and condensate effects. Thus refractories chosen for regenerator areas need resistance to these conditions in varying degrees depending on the particular area in the regenerator being considered. In addition to this list, a general characteristic required by checker brick is a good heat exchange value for thermal efficiency of the checkers.

It is probably not even necessary to point out that there has been a dramatic change in the last several years from conventional fireclay and mullite toward the use of basic refractories. The noteworthy exceptions to such practices occur with some special glasses. In borosilicate glass fireclay and mullite refractory checkers, regenerator walls and crowns are still generally used. There is some experimentation going on at present with high chrome refractories, Zircon, sintered AZS and some other basic materials. The primary practice in lead glass is to use silica checkers with fireclay in lower courses.

11. We have carefully studied the entire literature on Regenerator and also studied the diagrams. It follows that the advanced glass technology has brought improvements in the working of glass furnaces and in order to economise the 'port' and 'Regenerator' assembly function as part and parcel of the furnace. The construction of which has made it as an integral part of the furnace. It would not be able to repair the regenerator without shutting down the furnace altogether. It is not as though that Regenerator is a separate unit and has become an independent heat exchange unit. The notes as extracted, from Mc Graw Hill Encyclopedia of Science and Technology also clearly support this view. The learned Collector in his finding has also clearly held that 'No doubt, it is essential for the efficient functioning of a tank furnace since it conserves the heat energy and reduces the requirement of the fuel for combustion and even the tank furnace may be so designed that it can work only with the regenerator. Hence, when this position is technically accepted, then the notes 3 and 4 of Section XVI of the Customs Tariff would clearly apply. The notes 3 and 4 reads as follows -

"Unless the context otherwise requires, composite machines consisting of two or more machines fitted together to form a whole and other machines adapted for the purpose of performing two or more complementary or alternative functions are to be classified as if consisting only of that component or as being that machine which performs the principal function.

Where a machine (including a combination of machines consists of individual components (whether separate or interconnected by piping, by transmission devices, by electric cables or by other devices) intended to contribute together to a clearly defined function covered by one of the headings in Chapter 84 or Chapter 85, then the whole falls to be classified in the heading appropriate to that function."

The Explanatory notes under Heading 84.14 of CCCN is also extracted supra from the ruling of SAIL's case. The regenerator has become an integral part of the furnace and applying this note, the regenerator would have to be classified alongwith furnace. The SAIL's case has clearly laid down the principle on this aspect. The ratio supports our finding. The regenerator having become an integral part of the furnace, the refractory bricks imported in this case for replacement therein are, therefore, entitled to the benefit of the notification. The appeal is allowed with consequential benefits.