Metal working – Method of mechanical manufacture – Heat exchanger or boiler making
Reexamination Certificate
2000-02-04
2002-02-05
Rosenbaum, I Cuda (Department: 3726)
Metal working
Method of mechanical manufacture
Heat exchanger or boiler making
C029S890045
Reexamination Certificate
active
06343416
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an improved heat exchanger and a method for making the improved heat exchanger. The heat exchanger may be, for example, a condenser, an evaporator, a cooling tower or a heat sink.
2. Description of the Related Art
Many types of heat exchangers may be found in the prior art. These heat exchangers function to transfer heat from one body to another. In this application, the term “heat exchanger” is defined as any device which exchanges heat from one fluid to another fluid, to a solid or to the environment. Condensers, evaporators, cooling towers and heat sinks are considered to be examples of such heat exchangers.
FIG. 1
illustrates an example of a prior art auger type ice making machine disclosed in U.S. Pat. No. 5,664,434 including an evaporator type heat exchanger. An auger type ice making machine
10
includes a cylindrical refrigerated casing
11
having a cooling pipe
14
wound around the outer periphery thereof. An auger
12
having a spiral blade
13
are disposed on a columnar main body
12
A and mounted in the refrigerated casing
11
by being rotatably supported by bearings
20
a
and
20
b.
A shaft portion
12
a
of the auger
12
supported by the lower bearing
20
a
is coupled with the output shaft
17
of a drive motor
16
through a well-known spline coupling
18
, while a bar-shaped cutter
22
is disposed at the upper end of an upper side shaft portion
12
b
supported by the upper bearing
20
b.
The lower bearing
20
a
is accommodated in an approximately cylindrical support member
19
capable of being mounted on the lower end of the refrigerated casing
11
, while the upper bearing
20
b
is accommodated in a press head
21
mounted at the upper end of the refrigerated casing
11
. Although not shown, the press head
21
includes a plurality of concave ice compressing passages each extending in an axial direction and flake-shaped ice passing therethrough is compressed and formed into ice columns. The ice columns discharged into a discharge cylinder
23
from the press head
21
are cut off by the cutter
22
to form flaked ice
24
.
Further, the cooling pipe
14
is covered with a suitable heat insulating material
25
. A water supply pipe
26
is connected to the lower end of the refrigerated casing
11
so that a fluid can flow therethrough and ice making water from a not shown ice making water tank is supplied in to the refrigerated casing
11
through the water supply pipe
26
.
The combination of the cooling pipe
14
and refrigerated casing
11
may be considered the evaporator portion of the ice making machine
10
. When the auger type ice making machine
10
is operated, ice making water is supplied from the water supply pipe
26
to a predetermined water level in the refrigerated casing
11
, a not shown refrigerating unit is operated to cause a coolant (refrigerant, e.g.) to flow through the cooling pipe
14
. The refrigerated casing
11
and cooling pipe
14
act to transfer heat from the water to refrigerant in the cooling pipe
14
; heat from the ice making water flows through the refrigerated casing
11
, to the cooling pipe
14
and is absorbed by the refrigerant in cooling pipe
14
.
When the drive motor
16
is driven, the auger
12
is rotated through the output shaft
17
and the spline coupling
18
, an ice layer made around the inner periphery of the refrigerated casing
11
is fed upward while being scratched or scraped by the spiral blade
13
and put into the not shown ice compressing passages of the press
21
and compressed therein so as to form ice columns. The ice columns discharged into the discharge cylinder
23
from the ice compressing passages are cut off by the cutter
22
rotating together with the auger
12
to form ice cubes
24
each having a suitable length.
Making the heat transfer from the ice making water to the refrigerant more efficient, leads to a more efficient ice making machine; heat from the ice making water is more easily removed with less energy. One prior art procedure to improve heat transfer creates spiral grooves on the inside of cooling pipe
14
. Such a cooling pipe is known as rifled tubing, micro-finned tubing or inner-grooved tubing. This tubing has small ridges formed on its inside surface. These ridges may be created by forming a spiral groove on the inner surface of the tubing, thereby increasing the surface area of the inner surface of the tubing. The increased internal surface area reduces the liquid refrigerant film thickness which results in an increased effective temperature difference between the tube wall and the refrigerant gas-liquid interface, providing more heat transfer potential. The rifled tubing may also help promote annular flow, resulting in an increase in the amount of wetted surface area for evaporation. This type of tubing is disclosed in U.S. Pat. No. 4,660,630.
U.S. Pat. No. 4,660,630 also discusses modifications to the outside of a tube surface. The outside surface of a tube may be finned or knurled at some point in the manufacturing process to improve the efficiency of heat transfer tube.
However, while effective, rifled, finned, and knurled tubing is difficult to manufacture, and thus expensive. The additional cost of such tubing may not justify the increased efficiencies achieved by the rifled tubing. Further, when the use of tubing is not desired or required in a heat exchanger design, it can become even more complicated to decrease the thermal resistance of an irregularly shaped heat transfer surface by rifling, finning or knurling.
SUMMARY OF THE INVENTION
This invention is directed to an improved heat exchanger and a method for manufacturing an improved heat exchanger, where a surface of the heat exchanger has pits or bumps formed therein. These pits may be easily created by accelerating projectiles toward the surface of the heat exchanger and creating pits or bumps in a surface of the heat exchanger at portions where the projectiles impinge the surface of the heat exchanger.
REFERENCES:
patent: 747641 (1903-12-01), Rogerwald
patent: 1985381 (1934-12-01), Richards
patent: 1992988 (1935-03-01), Blahnik
patent: 2422517 (1947-06-01), Baker
patent: 2462012 (1949-02-01), Vilter
patent: 3566615 (1971-03-01), Roeder, Jr.
patent: 3643733 (1972-02-01), Hall et al.
patent: 3765192 (1973-10-01), Root
patent: 4218999 (1980-08-01), Shearer
patent: 4467622 (1984-08-01), Takahashi et al.
patent: 4580410 (1986-04-01), Toya
patent: 4588659 (1986-05-01), Abens et al.
patent: 4660630 (1987-04-01), Cunningham et al.
patent: 4741173 (1988-05-01), Neumann
patent: 4852368 (1989-08-01), Bravo
patent: 4924838 (1990-05-01), McCandless
patent: 5088192 (1992-02-01), Dempsey
patent: 5142878 (1992-09-01), Hida et al.
patent: 5249623 (1993-10-01), Müller et al.
patent: 5592840 (1997-01-01), Miyasaka
patent: 5596912 (1997-01-01), Laurence et al.
patent: 5664434 (1997-09-01), Sugie et al.
Miller Kristopher T.
Sugie Hiroyuki
Arent Fox Kintner & Plotkin & Kahn, PLLC
Cuda Rosenbaum I
Hoshizaki America Inc.
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