FORM 2
THE PATENT ACT, 1970
(39 OF 1970)
COMPLETE SPECIFICATION (See Section 10 and rule 13)
"USE OF COMMON FLOW DISTRIBUTOR OR FLOW DISTRIBUTORS IN MULTIPLE SHELLS HEAT EXCHANGER"
Applicant' Name: Kirloskar Pneumatic Company Limited. Address: Hadapsar Industrial Estate, Pune 411 013
The following specification particularly describes the invention and the matter in which it is to be performed.

A) TECHNICAL FIELD OF INVENTION
[001] The present invention relates to shell & tube heat exchanger with multiple shells.
B) BACKGROUND OF THE INVENTION
[002] A shell & tube heat exchanger is used for transfer of heat from one medium to another. They are widely used in space heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, sewage treatment and many more applications.
[003] In some applications, shell & tube heat exchangers installed at site are required to be replaced with new similar heat exchangers. If the transportation path at site has some obstructions which are not possible or not economical to be removed, then in those cases it is not possible to replace the existing shell & tube heat exchanger with similar heat exchanger.
[004] Therefore, where ever there is a space constraint or transportation difficulty, the existing method is using the two or more; smaller shell & tube replacement heat exchangers instead of single large shell & tube heat exchanger.
[005] Some examples of restricted space applications are installation on onshore platforms, basements of buildings, ships, submarines, space craft, underground shelters, mines etc.
[006] For ease of transportation, the replacement heat exchangers can be transported at site in disassembled condition, The maximum size of any part of replacement heat exchangers in disassembled condition is thus required to be lesser than the minimum space available at site or in transportation path. It is also important to consider turning radius available in transportation path. The maximum length of any part of replacement heat exchangers is thus required to be lesser than turning radius available in transportation path. While deciding the minimum space available in transport path one also has to consider space required for holding or supporting during transportation.

[007] In some cases two or more shell & tube replacement heat exchangers cannot be kept side by side because of width constraint at site. Similarly in some cases two or more shell & tube replacement heat exchangers cannot be placed one above another due to the height constraints. In some cases, the restriction of length does not allow the two or more shell & tube replacement heat exchangers to be placed longitudinally one after another.
[008] Almost all types of shell & tube heat exchangers typically require a shell & two ends covers. In few applications, the space available is so restricted that the accommodation of two end covers per each small shell & tube replacement heat exchanger is not feasible. This invention attempts to solve this difficulty by use of common flow distributor or flow distributors in multiple shells heat exchanger.
[009] This invention is also useful for ease of inspection & maintenance in cases where a very long shell & tube heat exchanger can be replaced by shell & tube heat exchanger having multiple shells & common flow distributor or flow distributors.
C) PRIOR ARTS ( EXISTING METHODS)
[010] Where ever there is a space constraint or transportation difficulty, a single large shell & tube heat exchanger can be replaced by two or more; smaller shell & tube replacement heat exchangers.
[011] The number of smaller shell & tube replacement heat exchangers can be equal or more than two. However for simplicity of understanding, while explaining prior art a single large shell & tube heat exchanger is shown replaced by only two smaller shell & tube replacement heat exchangers in FIG. 1, FIG. 2 & FIG 3.
[012] FIG. 1 illustrates a prior art design for replacement of single large shell & tube heat exchanger with two smaller shell & tube replacement heat exchangers. With respect to FIG. 1, the shell side fluid divided and the tube side fluid is also divided and flows through independent circuits. The design in FIG. 1 has a flaw that in certain areas this arrangement is not feasible due to limitation in width/height availability on an installation site.

[013] FIG. 2 illustrates another prior art design for replacement of single large shell & tube heat exchanger with two smaller shell & tube replacement heat exchangers. With respect to FIG. 2,' the shell side fluid is undivided i.e. the shell side fluid enters in first shell & tube replacement heat exchanger on shell side & then enters in the second shell & tube replacement heat exchanger. The tube side fluid is divided and maintains flow through independent circuits. The design in FIG. 2 has a flaw that in certain areas this arrangement is not feasible due to limitation in height availability on an installation site.
[014] FIG. 3 illustrates another prior art design for replacement of single large shell & tube heat exchanger with two smaller shell & tube replacement heat exchangers. With respect to FIG. 3, the shell side fluid is divided, while the tube side fluid is undivided. Tube side fluid enters in first shell & tube replacement heat exchanger & then enters in second shell & tube replacement heat exchanger. The design in FIG. 1 has a flaw that in certain areas this arrangement is not feasible due to limitation in length availability on installation site. For example in few applications, the available space at installation site is so restricted that the accommodation of two end covers per shell and tube replacement heat exchanger is not feasible. In some cases provision of piping, fittings & auxiliaries like flanges, bolts etc. make the arrangement complicated and costlier.
[015] The above mentioned shortcomings, disadvantages and problems are addressed herein, as detailed below.
D) OBJECTS OF THE INVENTION
[016] The primary object of the present invention is to provide a multiple shell heat exchanger with a common flow distributor which can be easily dismantled and mantled for shipping, assembled safely and easily during installation and maintenance.
[017] The other objects and advantages will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
E) SUMMARY OF THE INVENTION

[018] FIG. 4 illustrates concept of flow distributor. The tube side fluid travels though tubes in first pass of first heat exchanger (101) & enters in flow distributor (102). The fluid is then guided to pass through tubes in first pass of second heat exchanger (103). Then the fluid is diverted into the tubes in second pass of second heat exchanger (103) & comes back in flow distributor (102) & gets directed to flow through tubes in second pass of first heat exchanger (101) & so on. Finally fluid comes out from outlet nozzle provided on the end cover. The number of replacement heat exchangers can be two or more; similarly the number of passes can be one or more. The concept of flow distributor shall remain the same.
[019] The various embodiment of the present invention disclose a multiple shell heat exchanger. It should be understood, that the description, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
F) BRIEF DESCRIPTION OF THE DRAWINGS
[020] FIG. 1 illustrates a prior art design for replacement of single large shell & tube heat exchanger with two smaller shell & tube replacement heat exchangers. Shell side fluid is divided. Tube side fluid is also divided & flows in independent circuits.
[021] FIG. 2 illustrates a prior art design for replacement of single large shell & tube heat exchanger with two smaller shell & tube replacement heat exchangers. Shell side fluid is undivided. Tube side fluid is divided & flows in independent circuits. Shell side fluid is undivided. Tube side fluid is divided & flows in independent circuits.
[022] FIG. 3 illustrates a prior art design for replacement of single large shell & tube heat exchanger with two smaller shell & tube replacement heat exchangers. Shell side fluid is divided. Tube side fluid is undivided

[023] FIG. 4 illustrates a multiple shell heat exchanger with a common flow distributor. Shell side fluid is divided. Tube side fluid is guided by flow distributor.
[024] FIG. 5 illustrates a flow distributor suitable for connecting multiple shells of shell and tube replacement heat exchangers having two tube passes on tube side. The weep holes shown in the drawing is optional choice.
[025] FIG. 6 illustrates a flow distributor suitable for connecting multiple shells of shell and tube replacement heat exchangers having four tube passes on tube side. The weep holes shown in the drawing is optional choice.
G) DETAIL DESCRIPTION OF THE DRAWINGS
The following detailed description is not to be taken in a limiting sense.
[026] FIG. 1 illustrates a prior art design for replacement of single large shell & tube heat exchanger with two smaller shell & tube replacement heat exchangers. With respect to FIG. 1, the shell side fluid divided and the tube side fluid is also divided and flows through independent circuits. The design in FIG. 1 has a flaw that in certain areas this arrangement is not feasible due to limitation in width/height availability on an installation site.
[027] FIG. 2 illustrates another prior art design for replacement of single large shell & tube heat exchanger with two smaller shell & tube replacement heat exchangers. With respect to FIG. 2, the shell side fluid is undivided i.e. the shell side fluid enters in first shell & tube replacement heat exchanger on shell side & then enters in the second shell & tube replacement heat exchanger. The tube side fluid is divided and maintains flow through independent circuits. The design in FIG. 2 has a flaw that in certain areas this arrangement is not feasible due to limitation in height availability on an installation site.
[028] FIG. 3 illustrates another prior art design for replacement of single large shell & tube heat exchanger with two smaller shell & tube replacement heat exchangers. With respect to FIG. 3, the shell side fluid is divided, while the tube side fluid is undivided.

Tube side fluid enters in first shell & tube replacement heat exchanger & then enters in second shell & tube replacement heat exchanger. The design in FIG. 1 has a flaw that in certain areas this arrangement is not feasible due to limitation in length availability on installation site. For example in few applications, the available space at installation site is so restricted that the accommodation of two end covers per shell and tube replacement heat exchanger is not feasible. In some cases provision of piping, fittings & auxiliaries like flanges, bolts etc. make the arrangement complicated and costlier.
[029] FIG. 4 illustrates concept of flow distributor. The tube side fluid travels though tubes in first pass of first heat exchanger (101) & enters in flow distributor (102). The fluid is then guided to pass through tubes in first pass of second heat exchanger (103). Then the fluid is diverted into the tubes in second pass of second heat exchanger (103) & comes back in flow distributor (102) & gets directed to flow through tubes in second pass of first heat exchanger (101) & so on. Finally fluid comes out from outlet nozzle provided on the end cover. The number of replacement heat exchangers can be two or more; similarly the number of passes can be one or more. The concept of flow distributor shall remain the same.
[030] FIG. 5 illustrates a flow distributor suitable for connecting multiple shells of shell and tube replacement heat exchangers having two tube passes on tube side. The weep holes shown in the drawing is optional choice.
[031] FIG. 6 illustrates a flow distributor suitable for connecting multiple shells of shell and tube replacement heat exchangers having four tube passes on tube side. The weep holes shown in the drawing is optional choice.
Constructional Features: The flow distributor can be of any shape & size. Flow distributor's function is to guide the tube-side flow from one shell to another to which it connects. Therefore, generally the flow distributor shall be of same size to that of shells. If the connecting shells are of different sizes then the flow distributor shall also have different sizes to suit the flow. Therefore flow distributor can have cylindrical or conical shapes.

The pass partition plates can be provided inside the flow distributor as per tube side flow requirements. Fig 5 shows flow distributor with a single pass partition plate & Fig 6 shows flow distributor with a two pass partition plates. The weep holes shown in the drawing is optional choice.
It is possible to weld flanges to the flow distributor on its two ends. The flanges can then be bolted to tube sheets. The gaskets as necessary can be provided between the tube sheets & flanges. The flow distributor can be easily dismantled from the shell & tube heat exchanger by unbolting the bolts. Accessories like lifting lugs, sight glass etc. can be provided on the flow distributor.
H) ADVANTAGES OF THE INVENTION
[032] The use of common flow distributor, not only saves space of one end cover per two shell and tube replacement heat exchangers but also saves piping, fittings & auxiliaries like flanges, bolts etc.
[033] Instead of very long shell and tube heat exchanger, a person can use shell and tube heat exchangers having multiple shells with common flow distributor or flow distributors through the present invention's design for ease of inspection & maintenance.
[034] It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the claims.

We Claim:
1. A fluid flow system comprising a plurality of shell & tube heat exchangers;
a divided fluid flows as shell side flow in each shell of said plurality of shell & tube heat exchangers & an unmixed fluid flows as tube side flow in tubes /a tube of said plurality of shell & tube heat exchangers;
characterized in that
said plurality of shell and tube heat exchangers connected to each other by a flow distributor positioned between each adjacent shell and tube heat exchangers resulting in reduction in size for ease of shipping & accommodation at site of said fluid flow system
2. The Fluid flow system as claimed in claim 1, wherein size of fluid flow system is reduced in proportion to size of one end cover per two shell and tube replacement heat exchangers.
3. The fluid flow system as claimed in claim 1, wherein flow distributor is welded with flanges at its two ends, and these flanges are bolted to tube sheets.
4. The fluid flow system as claimed in claim 1, the fluid flow system as claimed in claim 1, wherein welded flanges of flow distributor are unbolted from tube sheets for maintenance & inspection.
5. The fluid flow system as claimed in claim 1, wherein the flow distributor is designed to have cylindrical or conical shape to connect two shells.
6. The fluid flow system as claimed in claim 1, wherein the flow distributor is having a plurality of partitions for allowing tube passes in shell and tube heat exchanger equal to double in number than the plurality of partitions.

7. The fluid flow system as claimed in claim 1, wherein cost and maintenance of fluid flow system is reduced due to lesser piping, fittings & auxiliaries fittings like flanges, bolts etc. for each shell and heat tube exchanger.