U.S. patent application number 12/754307 was filed with the patent office on 2011-10-06 for helicoid turbulator for heat exchangers.
Invention is credited to Bryan C. Holland, Jack C. Holland.
Application Number | 20110240266 12/754307 |
Document ID | / |
Family ID | 44708270 |
Filed Date | 2011-10-06 |
United States Patent
Application |
20110240266 |
Kind Code |
A1 |
Holland; Bryan C. ; et
al. |
October 6, 2011 |
HELICOID TURBULATOR FOR HEAT EXCHANGERS
Abstract
The present invention teaches an assembly for improved heat
transfer consisting of a helix surrounding a self contained tube
that is placed inside a heat exchanger tube parallel to fluid flow
with the outside of the helix in close proximity to the inside wall
of the heat exchanger tube and the invention assembly self
contained tube in close proximity to the inside of the helix.
Inventors: |
Holland; Bryan C.; (Dallas,
TX) ; Holland; Jack C.; (Dallas, TX) |
Family ID: |
44708270 |
Appl. No.: |
12/754307 |
Filed: |
April 5, 2010 |
Current U.S.
Class: |
165/109.1 |
Current CPC
Class: |
F28F 1/30 20130101; F28F
13/12 20130101 |
Class at
Publication: |
165/109.1 |
International
Class: |
F28F 13/12 20060101
F28F013/12 |
Claims
1. A heat exchanger system for increased heat transfer in a fluid
flowing through the heat exchanger system, the heat exchanger
system comprising: a. a first tube; b. a second tube, the second
tube being present inside the first tube, the second tube being
concentric with the first tube; and c. a helicoid structure wrapped
around the second tube.
2. The heat exchanger system according to claim 1, wherein the
helicoid structure possesses a variable pitch.
3. The heat exchanger system according to claim 1, wherein the
first tube is a cylindrical tube possessing an inlet and an outlet
to allow the fluid flow through the heat exchanger system.
4. The heat exchanger system according to claim 1, wherein the
second tube is a cylindrical tube possessing an inlet and an outlet
for facilitating fluid flow.
5. The heat exchanger system according to claim 1, wherein the
second tube is capable of possessing varying diameter.
6. The heat exchanger system according to claim 1 or 5, wherein
diameter of the second tube is 3/4 of diameter of the first
tube.
7. The heat exchanger system according to claim 1, wherein outer
edge of the second tube is in proximity to the inner edge of the
helicoid structure.
8. The heat exchanger system according to claim 7, where in range
of the proximity is 1/8 of an inch and lower.
9. The heat exchanger system according to claim 1 further
comprising a plurality of extended surface fins, the plurality of
extended surface fins surrounding the first tube.
10. The heat exchanger system according to claim 1, wherein the
helicoid structure is manufactured from one of carbon steel,
stainless steel and other non-corrosive material.
11. A heat exchanger system for transferring heat from a viscous
fluid flowing in a laminar state, the heat exchanger system
comprising: a. a first cylindrical tube; b. a second cylindrical
tube, the second cylindrical tube being present inside and
concentric with the first cylindrical tube; c. a helix, the helix
surrounding the second cylindrical tube, the helix being a helicoid
structure wrapped around the second tube; and wherein the helix
surrounding the first cylindrical tube is placed parallel to the
flow of the viscous fluid inside the heat exchanger system and
outside of the helix is in close proximity to inside wall of the
first tube.
12. The heat exchanger system according to claim 11, wherein the
helix possesses a variable pitch.
13. The heat exchanger system according to claim 11, wherein the
second cylindrical tube is capable of possessing a varying
diameter.
14. The heat exchanger system according to claim 11, wherein outer
edge of the second cylindrical tube is in close proximity to the
inner edge of the helix.
15. The heat exchanger system according to claim 11 further
comprising a plurality of extended surface fins, the plurality of
extended surface fins surrounding the first cylindrical tube.
16. The heat exchanger system according to claim 11, wherein the
helix is manufactured from one of carbon steel, stainless steel and
other non-corrosive material.
17. The heat exchanger system according to claim 11, where in range
of the proximity is 1/8 of an inch and lower.
18. A heat exchanger system for heat transfer at one or more
locations along the path of the fluid, the fluid comprising a first
portion and a second portion, the system comprising: a. a first
tube, the first tube being a heat exchanger tube; b. a turbulator;
the turbulator being concentric with the first tube, the turbulator
comprising: i. a second cylindrical tube, the second cylindrical
tube being present inside the first tube; ii. a helix, the helix
surrounding the second tube, the helix being a helicoid structure
wrapped around the second tube; wherein the first portion of the
fluid being controlled by the helix and flowing in a spiral
portion, the first portion being the fluid portion confined between
the turbulator and the first tube; and wherein the second portion
of the fluid being the fluid passing inside the second cylindrical
tube.
19. A method of increased heat transfer in a heat exchanger system,
the heat exchanger system comprising a first tube and turbulator,
the turbulator being present inside the first tube, the turbulator
comprising a second tube surrounded by a helix, wherein the heat
transfer occurs at one or more locations along the flow path of
fluid, the fluid flow path comprising a first portion and a second
portion, the method comprising: a. transferring heat along path of
the first portion of the fluid, the first portion being the portion
present between the first tube and the turbulator; the first
portion being subjected to spiral path of the helix and reduced
thickness of the fluid flow; and b. transferring heat along path of
second portion of the fluid, the second portion of the fluid being
the fluid passing inside the turbulator.
20. The method according to claim 19, wherein varying diameter of
the turbulator facilitates controlling pressure loss through the
heat exchanger system.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to heat exchangers for
improved heat transfer along the path of fluid flow. More
specifically, the present invention relates to an improved heat
exchanger comprising a turbulator for transferring heat from a
viscous fluid flowing in a laminar state.
[0003] 2. Description of the Prior Art
[0004] Generally, heat exchangers that utilize round tubes
connected in plurality and surrounded in a secondary enclosure with
captivated fluids on both sides of the tubes are referred to as
Shell and Tube Exchangers. Air Cooled Exchangers utilize extended
surfaces on the outside of the tubes for forced air convection.
Double Pipe Exchangers consist of a single heat exchanger tube
enclosed with another larger tube with isolation to provide for
captivated fluids on both sides of the tubes.
[0005] The velocity characteristics of fluids moving through tubes
in heat exchangers and the fluid condition thereof have a velocity
component known as the Reynold's Number. The Reynold's Number is
determined by the fluid velocity, the fluid mass, the fluid
viscosity, and other properties. Generally, fluid flow is laminar
if the Reynold's Number is below 2000, is in transition of becoming
turbulent when the Reynold's Number is between 2000 and 8,000, and
is normally turbulent above 8000. When fluid flow inside the heat
exchanger tube is laminar, the fluid moves through the tube in
layers, unmixed, and that portion of the fluid that is in contact
with the tube wall stagnates at a lower flow velocity providing an
insulation effect retarding heat transfer from the center and
surrounding volume of the flowing fluid to the heat exchanger tube
interior wall. Conversely, when the flow reaches a higher Reynold's
Number and becomes turbulent, that portion of the fluid in contact
with the tube wall is continuously displaced which reduces the tube
wall stagnation and provides higher heat transfer rates.
[0006] The basic underlying principle behind how a turbulator works
is the first law of thermodynamics, which is the application of the
conservation of energy principle applied to the heat and
thermodynamic process. The first law of thermodynamics states that
the change in internal energy of a system (.DELTA.U) is equal to
the heat added to the system (Q) plus the work done to the system
(W) or .DELTA.U=Q+W. For turbulator design, the work done to the
system (W) is the allowable pressure drop, and the change in
internal energy (.DELTA.U) of the system is the amount of heat
transfer. The laminar flow issue mentioned above has a long history
of improvement efforts by those skilled in the art of fluid flow
and heat transfer. In 1906 a twisted ribbon device placed inside a
housing captivating fluid flow was awarded a patent (U.S. Pat. No.
808,752) and was perhaps the first recorded effort to improve fluid
flow heat transfer by creating a swirl fluid flow and increased
fluid velocities with a finite work input. There have been numerous
patents granted, as noted under "References Cited", covering a
variety of modifications to twisted ribbons such as scoops along
the body of the twisted ribbon, discontinuous outer edges, pleats,
and others. These variations to twisted ribbons have merit for
fluids with characteristics that permit the fluids to become
turbulent with an increase in work, W (pressure drop), but serve
little useful purpose for viscous fluids that flow in a laminar
fashion as they consume the input work in the form of pressure drop
with no appreciable change to the energy of the system, .DELTA.U
(heat transfer).
[0007] When laminar fluid flows unobstructed through a heat
exchanger tube, the portion of the fluid the greatest distance from
the inner wall of said tube experiences the least heat transfer.
This is because the layers created by the laminar flow insulate the
layers and the farther the layers are from the heat exchanger tube
wall the less heat transfer occurs. Reducing the tube size, with
constant fluid flow velocity, reduces the thickness of the
insulating layers and allows a higher level of fluid flow heat
transfer. Thus, at constant fluid flow velocity and temperature, a
smaller diameter tube will transfer a higher heat rate to the heat
exchanger tube wall than will a larger diameter tube.
[0008] Utilizing a tube at the center of the invention assembly
allows the designer latitude to control and vary the pressure loss
through the heat exchanger by varying the diameter of the assembly
tube and the resulting dimension of the helix component. In
conjunction with the ability to control the invention assembly
pressure loss through the heat exchanger by varying the tube and
helix cross-sectional dimensions, the designer can further enhance
the invention assembly application with the insertion of twisted
ribbon or other low pressure drop heat transfer media to the inside
of the invention assembly integral tube to optimize the overall
heat transfer rates and system allowable pressure loss.
[0009] In light of the foregoing discussion, there is a need for an
improved heat exchanger system which overcomes the disadvantages as
posed by the prior art and provides an improved heat exchanger
system with improved heat transfer.
SUMMARY OF THE INVENTION
[0010] An object of the present invention is to provide a heat
exchanger system for improved heat transfer heat transfer by
increasing the velocity of the flowing fluid and by fluid mixing to
minimize laminar layers.
[0011] Another object of the present invention is to provide a heat
exchanger system comprising a turbulator placed inside a heat
exchanger tube parallel to fluid flow for increasing heat transfer
along the flow path of the fluid.
[0012] In accordance with an embodiment of the present invention,
the present invention teaches a method and system for heat
exchanger system for increased heat transfer in a fluid flowing
through the heat exchanger system comprising a first tube, a second
tube and a helicoid structure wrapped around the second tube. The
second tube along with the wrapped helicoid structure being present
inside the first tube leads to increased velocity of the fluid in
the heat exchanger system.
[0013] In accordance with another embodiment of the present
invention, the present invention teaches a method and system for
transferring heat from a viscous fluid flowing in a laminar state.
The heat exchanger system comprising a first cylindrical tube, a
second cylindrical tube and helix structure. The second cylindrical
tube is present in the first tube and is concentric with the first
tube. The helix is a helicoid structure wrapped around the second
tube. The helix surrounding the second tube is placed parallel to
the flow of the viscous fluid inside the heat exchanger system and
the outside of the helix is in close proximity to inside wall of
the first tube.
[0014] In accordance with another embodiment the present invention
teaches a heat exchanger system, comprising a first tube and a
turbulator, for heat transfer at one or more locations along the
path of the fluid. The fluid comprises a first portion and a second
portion. The first tube is a heat exchanger tube. The turbulator is
present inside the first tube and is concentric with the first tube
and comprises a second cylindrical tube and a helix. The helix is a
helicoid structure wrapped around the second tube. The first
portion of the fluid is the fluid portion confined between the
turbulator and the first tube and flowing in a spiral portion due
to the helix. The second portion of the fluid is the fluid passing
through the second cylindrical tube.
[0015] The present invention increases the heat transfer rate of
the tube surface of the heat exchanger system. Further, the present
invention reduces the cost and size, both of which are highly
desirable. The present invention reduces the size and cost of heat
exchangers used in commercial, industrial, natural gas gathering,
and petro-chemical applications by increasing the heat transfer
rates, while reducing the pressure loss, of the heat exchanger
tubes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] For a more complete understanding of the present invention,
the needs satisfied thereby, and the objects, features, and
advantages thereof, reference now is made to the following
description taken in connection with the accompanying drawings.
[0017] FIG. 1 shows a heat exchanger system according to an
embodiment of the present invention.
[0018] FIG. 2 shows a cross-sectional view of the heat exchanger
system according to an embodiment of the present invention.
[0019] FIG. 3 shows a heat exchange tube with plurality of extended
surface fins wrapped around according to an embodiment of the
present invention.
[0020] FIG. 4 shows an isometric side view of the turbulator
according to an embodiment of the present invention.
[0021] Skilled artisans will appreciate that elements in the
figures are illustrated for simplicity and clarity and have not
necessarily been drawn to scale. For example, the dimensions of
some of the elements in the figures may be exaggerated relative to
other elements to help to improve understanding of embodiments of
the present invention
DETAILED DESCRIPTION OF THE DRAWINGS
[0022] Before describing in detail the particular method and system
for heat exchange in accordance with an embodiment of the present
invention, it should be observed that the present invention resides
primarily in combinations of system components related to the
device of the present invention.
[0023] Accordingly, the system components have been represented
where appropriate by conventional symbols in the drawings, showing
only those specific details that are pertinent to understanding the
present invention so as not to obscure the disclosure with details
that will be readily apparent to those of ordinary skill in the art
having the benefit of the description herein.
[0024] In this document, relational terms such as `first` and
`second`, and the like may be used solely to distinguish one entity
or action from another entity or action without necessarily
requiring or implying any actual such relationship or order between
such entities or actions. The terms `comprises`, `comprising`, or
any other variation thereof, are intended to cover a non-exclusive
inclusion, such that a process, method, article, or apparatus that
comprises a list of elements does not include only those elements
but may include other elements not expressly listed or inherent to
such process, method, article, or apparatus. An element proceeded
by `comprises . . . a` does not, without more constraints, preclude
the existence of additional identical elements in the process,
method, article, or apparatus that comprises the element.
[0025] The present invention discusses a heat exchanger system
comprising a heat exchanger tube and a turbulator. The turbulator
comprising a helix portion wrapped around a self contained tube,
the self contained tube concentric to the heat exchanger tube. The
heat transfer occurs in two places simultaneously along the path of
the fluid flow through the heat exchanger tube. First, the outer
portion of the fluid flow is controlled by the helix. The fluid
flows in a spiral motion confined between the inside of the heat
exchanger tube and the outer surface of the turbulator. This fluid
experiences a high heat transfer rate to the inside of the heat
exchanger tube resulting from the high fluid velocity generated by
the spiral path of the helix and the reduced thickness of the fluid
flow. Secondly, the portion of the fluid flow passing through the
second tube, possessing a reduced cross-sectional dimension
compared to the first tube, is exposed to the high velocity of the
first fluid flow mentioned above flowing around the outer surface
of the invention assembly second tube.
[0026] The present invention is directed at providing an improved
heat exchanger tube turbulator for use in transferring heat from a
viscous fluid flowing in a laminar state. It is to be understood
that the specific embodiment of the heat exchanger tube turbulator
shown on the drawing is merely illustrative of the preferred
embodiment and presently contemplated by the applicant for carrying
out the invention and is by no means meant as a limitation to the
many varied forms of heat exchangers to which the invention may be
applicable. Accordingly, it is intended that any modifications
which is apparent to those skilled in the art in light of the
foregoing description and which falls within the spirit and scope
of the appended claims be included in the invention as recited
therein.
[0027] FIG. 1 shows a heat exchanger system 100 according to an
embodiment of the present invention. The heat exchanger system 100
includes a first tube 102; also referred to as the heat exchanger
tube, a plurality of extended surface fins 104, a helicoid
structure 106, a second tube 108, a fluid 110, a first portion 112
of the fluid 110 and a second portion 114 of the fluid 110.
[0028] The first tube 102 and the second tube 108 are concentric
and are placed along the same axis.
[0029] According to an embodiment of the present invention, the
first tube 102 and the second tube 108 are cylindrical tubes
possessing an inlet and outlet for facilitating the fluid flow
through the heat exchanger system 100.
[0030] According to another embodiment of the present invention,
the second tube 108 is a piece of sheet metal "roll formed" into a
cylinder.
[0031] According to yet another embodiment of the present
invention, the sheet metal possesses a small gap where the two
edges of the "roll formed" sheet metal touch.
[0032] The helicoid structure 106 is wrapped around the second tube
108. The assembly, including the helicoid structure 106; also
referred to as the helix, and second tube 108, hereinafter also
referred to as the turbulator, is contained within the first tube
102. The outer edge of the helicoid structure 106 is in close
proximity to the inside wall of first tube 102. The first tube 102
is a heat exchanger tube. The outer edge of the second tube 108 is
in close proximity to the inner edge of the helicoid structure 106.
The helicoids structure 106 is manufactured from one of a carbon,
stainless steel or other non-corrosive material.
[0033] According to an embodiment of the present invention, the
helicoid structure 106 is a helical structure.
[0034] The flow of the fluid 110 in the first tube 102 is divided
into two lesser flows. A first portion 112 passes between the
inside of the first tube 102 and the outside of the second tube 108
within the confines of the helicoid structure 106. The second
portion 114 of the fluid flow passes through the second tube
108.
[0035] The configuration provided by the present invention subjects
flow of first portion 112 of fluid being confined inside the spiral
of the helicoid structure 106, increasing the heat transfer rate,
but allowing the second portion 114 of the fluid passing through
the center of the second tube 108 to pass unobstructed, thus
reducing pressure drop and significantly increasing the overall
efficiency of the heat exchanger system 100.
[0036] The heat transfer occurs in two places simultaneously along
the flow path of the fluid 110 through the heat exchanger tube.
First, the outer portion of the fluid flow i.e. the first portion
112 of the fluid is controlled by the helix and flowing in a spiral
motion confined between the inside of the heat exchanger tube and
the outer surface of the turbulator experiences a high heat
transfer rate to the inside of the heat exchanger tube resulting
from the high fluid velocity generated by the spiral path of the
helix and the reduced thickness of the fluid flow. Secondly, the
second portion of the fluid 114 passing through the turbulator,
possessing a reduced cross-sectional dimension compared to the heat
exchanger tube, is exposed to the high velocity of the first
portion of the fluid 112 flowing around the outer surface of the
turbulator.
[0037] According to an embodiment of the present invention, the
diameter of the second tube 108 is typically not greater than 3/4
of the diameter of the first tube 102. For example, if the diameter
of the first tube 102 is 1 inch, the second tube 108 would normally
possess a diameter of not greater than 0.750 inches.
[0038] According to an embodiment of the present invention, the
heat exchanger system 100 does not include the plurality of surface
extended fins 104, particularly in case of shell and tube heat
exchangers.
[0039] According to yet another embodiment of the present
invention, the plurality of extended surface fins 104 run
longitudinally to the first tube 102.
[0040] FIG. 2 shows a cross-sectional view of the heat exchanger
system 100 according to an embodiment of the present invention. The
heat exchanger system 100 includes the first tube 102, the
plurality of extended surface fins 104, the helicoid structure 106
and the second tube 108. The first tube 102 and the second tube 108
are concentric and are placed along the same axis. The helicoid
structure 106 is wrapped around the second tube 108. The
turbulator, consisting of a helicoid structure 106 and second tube
108, is contained within the first tube 102. The turbulator is
shown in cross section A-A' within the confines of a heat exchanger
tube which is surrounded by the plurality of extended surface fins
104 as used in a forced convection air cooler.
[0041] According to an embodiment of the present invention, the
first tube 102 and the second tube 108 are the first cylindrical
tube and the second cylindrical tubes respectively with the helix
surrounding the second cylindrical tube. The helix surrounding the
second cylindrical tube is placed parallel to the flow of the
viscous fluid inside the first cylindrical tube. The outside of the
helix is in close proximity of to the inside wall of the first
cylindrical tube.
[0042] According to an embodiment of the present invention, the
range of the proximity between the first tube 102 and the helicoid
structure 106 is 1/8 of an inch and lower.
[0043] FIG. 3 shows a heat exchange tube 102 with the plurality of
extended surface fins 104 around according to an embodiment of the
present invention.
[0044] FIG. 4 shows an isometric side view of the turbulator
according to an embodiment of the present invention. The turbulator
includes the helicoid structure 106 and the second tube 108.
[0045] The present invention increases the heat transfer rate of
the tube surface of the heat exchanger system. Further, the present
invention reduces the cost and size, both of which are highly
desirable. The present invention reduces the size and cost of heat
exchangers used in commercial, industrial, natural gas gathering,
and petro-chemical applications by increasing the heat transfer
rates of the heat exchanger tubes.
[0046] While the drawings illustrate the turbulator as associated
with a heat exchanger designed for transferring heat of laminar
fluids, it is contemplated that the turbulator can be used for
other applications where it is desired to increase heat transfer
for any medium flowing through the heat exchanger tubes.
[0047] While the present invention has been described in connection
with preferred embodiments, it will be understood by those skilled
in the art that variations and modifications of the preferred
embodiments described above may be made without departing from the
scope of the invention. Other embodiments will be apparent to those
skilled in the art from a consideration of the specification or
from a practice of the invention disclosed herein. It is intended
that the specification and the described examples are considered
exemplary only, with the true scope of the invention indicated by
the following claims.
* * * * *