Electric resistance heating devices – Heating devices – Continuous flow type fluid heater
Reexamination Certificate
2001-06-12
2003-12-23
Paik, Sang V. (Department: 3742)
Electric resistance heating devices
Heating devices
Continuous flow type fluid heater
C165S154000
Reexamination Certificate
active
06668136
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to an integral heating and cooling unit and, more particularly to a unit integrating electric heating elements and a cooling heat exchanger.
BACKGROUND OF THE INVENTION
Many applications in manufacturing and other fields require controlling the temperature of a fluid. For example, in the field of plastics, the temperature for the dies used for injection molds must be carefully controlled. A heat transfer or working fluid is used to bring the dies to an elevated temperature. Sometimes, the temperature must be rapidly reduced to properly facilitate the injection molding process. In this instance, the working fluid must be quickly cooled. To heat and cool the working fluid for the dies, a separate heater and cooling heat exchanger may be used to control the temperature of the working fluid.
The common approach in the prior art to create a system that both heats and cools a working fluid typically involves plumbing or connecting a heater to a cooler.
FIG. 1
illustrates a system
10
that is capable of heating and cooling a working fluid. A heater unit
40
is plumbed or piped to a cooling unit
50
to achieve both heating and cooling of a working fluid
12
according to the prior art. The working fluid
12
, such as a heat transfer fluid or oil, enters the system
10
via a pipe
20
. The pipe
20
connects to the heating unit
40
, which includes a heating element
42
. The connection of the pipe
20
to the heating unit
40
involves a joint or weld
30
to assemble. The working fluid
12
passes through the heating unit
40
where heat from the heating element
42
elevates the temperature of the fluid
12
.
The working fluid
12
then leaves the heating unit
40
via a plumbing pipe
22
. The plumbing pipe
22
brings the heated working fluid
12
to a cooling unit
50
. One type of cooling unit
50
is a heat exchanger that uses a cooling fluid
52
to drop the temperature of the working fluid
12
. The plumbing of the heating unit
40
to the cooling unit
50
with the pipe
22
involves additional joints or welds
31
,
32
to assemble. The cooling fluid
52
, such as water, enters the cooling unit
50
via a pipe
54
. The connection of the pipe
54
to the cooling unit
50
also involves a joint or weld
33
to assemble.
In the cooling unit
50
, heat from the working fluid
12
may transfer to the cooling fluid
52
depending on the heat transfer characteristics of the cooling unit
50
and the mass flow rates of the two fluids
12
,
52
. The working fluid
12
then leaves the cooling unit
50
via pipe
24
, and the cooling fluid
52
leaves the heat exchanger through a pipe
56
. The connections of the pipes
24
,
56
to the heat exchanger
50
also involves joints or welds
34
,
35
to assemble.
The difficult assembly of all of the components and the space required for those components presents one problem in the prior art system
10
that both heats and cools. Plumbing the heater unit
40
to the cooling unit
50
affects the number of components and amount of piping required in assembling the system
10
. The increased number of components also multiplies the number of joints or welds
30
-
35
required, which in turn results in a greater potential for leaks to occur. Additional insulation of the system may be necessary with the increased amount of piping. Similarly, the increased number of components also adds to the cost for the system
10
.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
SUMMARY OF THE INVENTION
To that end, the present invention includes an integral heating and cooling unit for controlling the temperature of a working fluid. The heating and cooling unit has an outer housing, at least one electric heating element, and a cooling heat exchanger. The outer housing defines a plenum and has a working fluid inlet, a working fluid outlet, a cooling fluid inlet, and a cooling fluid outlet. The working fluid inlet and outlet are in fluid communication with the plenum. The electric heating element is attached to the outer housing and extends into the plenum to heat the working fluid. The cooling heat exchanger is attached to the outer housing and extends through the plenum to cool the working fluid. The cooling heat exchanger is capable of receiving a cooling fluid from the cooling fluid inlet and sending the cooling fluid to the cooling fluid outlet.
The outer housing may further include a first flange, a second flange, and a tubular shell. In this embodiment, the tubular shell slides over the flanges and is welded to the outer perimeter of the flanges. The cooling heat exchanger may have a variety of designs. In one design, the cooling heat exchanger includes a tube and a plurality of longitudinal fins. The tube is attached to the first and second flanges. In a second design, the cooling heat exchanger includes a tube that is at least partially corrugated. The tube (with corrugations) is attached to the first and second flanges. In yet a third design, the cooling heat exchanger includes a spiral tube having two ends. The ends of the spiral tube are attached to the first and second flanges. In a fourth design, the inlet and outlet of the cooling heat exchanger are attached to the same flange. The cooling heat exchanger is coiled and extends within the outer housing.
In another embodiment, the present invention includes an integral heating and cooling unit for controlling the temperature of a working fluid. However, in this embodiment, the heating and cooling unit has an inverse arrangement of the heating and cooling function. The heating and cooling unit has an outer housing, a heat exchanger, and at least one electric heating element. The outer housing defines a plenum and has a working fluid inlet, a working fluid outlet, a cooling fluid inlet, and a cooling fluid outlet. The cooling fluid inlet and the cooling fluid outlet are in fluid communication with the plenum. The heat exchanger is attached to the outer housing and extends through the plenum. The heat exchanger is capable of receiving the working fluid from the working fluid inlet and sending the working fluid to the working fluid outlet. The electric heating element extends within the heat exchanger and is capable of heating the working fluid.
Another embodiment of the present invention includes a system for heating and cooling a working fluid. The system includes a controller, a working fluid flow control means, and a heating and cooling unit. The working fluid flow control means is electrically connected to the controller to control the flow of the working fluid. The heating and cooling unit has an outer housing, at least one electric heating element, and a cooling heat exchanger. The outer housing defines a plenum to carry the working fluid. The electric heating element is mounted to the outer housing and electrically connected to the controller. The electric heating element extends into the plenum and is capable of heating the working fluid. The cooling heat exchanger is mounted to the outer housing and extends through the plenum. The cooling heat exchanger is capable of cooling the working fluid.
The system may further include a cooling fluid flow control means that is electrically connected to the controller to control the flow of a cooling fluid. The outer housing of the heating and cooling unit has a working fluid inlet, a working fluid outlet, a cooling fluid inlet, and a cooling fluid outlet. The cooling heat exchanger is capable of receiving the cooling fluid from the cooling fluid inlet and sending the cooling fluid to the cooling fluid outlet. The outer housing may further include a first flange, a second flange, and a tubular shell. The tubular shell is attached to the first and second flanges. The heat exchanger for the system may also have several designs including a tube with fins, a tube that is at least partially corrugated, and a tube that is at least partially spiral or coiled.
In another embodiment of the present invention,
Cunningham Donald M.
Henry Sam W.
Jarrett Randy C.
Neilson Paul
Nestel Steven U.
Campbell Thor
Chromalox, Inc.
Kirkpatrick & Lockhart LLP
Paik Sang V.
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