Refrigeration – Automatic control – Refrigeration producer
Reexamination Certificate
1999-11-04
2001-05-22
Tanner, Harry B. (Department: 3744)
Refrigeration
Automatic control
Refrigeration producer
C062S185000, C062S201000
Reexamination Certificate
active
06233955
ABSTRACT:
INDUSTRIAL FIELD OF THE INVENTION
The present invention relates to an isothermal coolant circulating apparatus for supplying and circulating isothermal coolant to a load.
DESCRIPTION OF THE RELATED ART
FIG. 5
shows an example of conventional isothermal coolant circulating apparatuses. This constant-temperature coolant circulating apparatus
1
comprises a refrigerating circuit section
3
for cooling a coolant raised in temperature by a load
2
, a coolant circuit section
4
for supplying and circulating coolant cooled by refrigerant in the refrigerating circuit section
3
to the load
2
after adjusting it to a predetermined temperature, and a controlling section
5
for controlling the temperature of coolant for supplying to the load
2
.
The above-mentioned refrigerating circuit section
3
is formed of a compressor
7
for compressing an appropriate refrigerant to be high-temperature-and-pressure refrigerant gas, a condenser
8
for cooling and condensing the refrigerant gas to be high pressure refrigerant liquid, a pressure-reducing unit
9
for reducing pressure of the refrigerant liquid to reduce the temperature thereof, and an evaporator
10
for evaporating the refrigerant liquid reduced in pressure by the pressure reducing unit
9
, these being sequentially connected to each other in series. The pressure-reducing unit
9
controls the pressure of refrigerant in the lower course thereof.
The above-mentioned refrigerating circuit section
3
further comprises a return-current circuit
12
for returning refrigerant liquid condensed in the condenser
8
from the outlet of the condenser
8
to the inlet of the compressor
7
when the temperature of refrigerant in the outlet of the evaporator
10
is high, and a thermostatic expansion valve
13
disposed in the return-current circuit
12
. The thermostatic expansion valve
13
is controlled by a temperature sensor
14
for detecting the temperature of refrigerant being returned to the compressor
7
to produce signals. The refrigerating circuit section
3
also includes an overheat-preventing circuit
15
for preventing overheat of the compressor
7
, disposed in the upper course of the thermostatic expansion valve
13
in the return-current circuit
12
. The overheat preventing circuit
15
is formed of an injection valve
16
and a capillary tube
17
, these being arranged in series.
The coolant circuit section
4
comprises a coolant tank
24
, a heat exchanger
25
for cooling coolant raised in temperature by the load
2
, a heater unit
26
having a heater
27
for heating coolant cooled by the heat exchanger
25
, a pump
28
for supplying and circulating coolant adjusted to a predetermined temperature in the tank
24
to the load
2
, and a level switch
29
for detecting the coolant level in the tank
24
. The heat exchanger
25
, the heater unit
26
, and the pump
28
are all assembled to within the tank
24
. In the outer periphery of the heater
27
, a cylindrical-shaped heater cover
30
with the top thereof opened and having a bottom is disposed surrounding the heater
27
.
The above-mentioned heat exchanger
25
incorporated thereinto by the evaporator
10
in the refrigerating circuit section
3
is connected to a return pipe
32
of coolant returning from the load
2
at its inlet and the outlet thereof is connected to a pipe
33
communicating with the bottom portion of the heater cover
30
.
In a supplying pipe
36
connected to the delivery opening of the pump
28
, a temperature sensor
37
for detecting the temperature of coolant flowing within the pipe is disposed, and a pressure gauge
38
for detecting the coolant pressure in the delivery side and a low-pressure cut-out switch
39
for producing signals when the pressure detected by the pressure gauge
38
decreases below a predetermined pressure are disposed downstream of the temperature sensor
37
.
On the bottom wall of the tank
24
, a drainpipe
40
for discharging coolant in the tank
24
is disposed.
The above-mentioned controlling section
5
is for controlling the overall apparatus and comprises a temperature controller
42
for producing necessary signals in accordance with the temperature signal from the temperature sensor
37
, a programmable logic controller (abbreviated to “PLC” below)
43
for producing necessary signals in accordance with the signals from the level switch
29
in the tank
24
, the low-pressure cut-out switch
39
, and a high-pressure refrigerant cut-out switch
20
, an electromagnetic contactor/electromagnetic switch
44
for controlling the operations of the compressor
7
and the pump
28
, electrically charging the heater
27
, and controlling the injection valve
16
in accordance with respective signals produced by the temperature controller
42
and the “PLC”
43
, and an operational display panel
45
for indicating necessary information.
In the coolant circuit section
4
, when the coolant raised in temperature by the load
2
flows in the heat exchanger
25
through the return pipe
32
, it is cooled by low-temperature refrigerant flowing in the evaporator
10
in the refrigerating circuit section
3
so as to flow into the heater cover
30
. Then, the coolant heated to a predetermined temperature by the heater
27
flows into the tank
24
from the top opening of the heater cover
30
. This coolant is supplied to the load
2
by the pump
28
for cooling it.
Since the above-described isothermal coolant circulating apparatus
1
cools coolant raised in temperature by the load
2
by means of the heat exchanger
25
and heats this coolant to a predetermined temperature by the heater
27
, the adjustment of the coolant temperature is easy.
However, since the isothermal coolant circulating apparatus
1
heats the coolant cooled in the heat exchanger
25
by means of the heater
27
, the required electric power for operation is increased. In particular, the compressor
7
, the pump
28
, and the heater
27
may be simultaneously electrically charged according to the operational conditions, such that the allowable capacity of electrical charging the circulating apparatus
1
necessary for operation is required to be increased in order to cope with the situation, resulting in increase of the cost of equipment for electrical charging,
DISCLOSURE OF THE INVENTION
It is a problem to be solved by the present invention to provide an isothermal coolant circulating apparatus offering energy-saving and enabling the cost of operation and equipment to be reduced.
In order to solve the above-mentioned problem, in accordance with one aspect of the present invention, there is provided an isothermal coolant circulating apparatus comprising a coolant circuit section for cooling coolant returned from a load to a predetermined temperature and for supplying the coolant to the load, and a refrigerating circuit section for cooling the coolant, wherein the refrigerating circuit section comprises a hot gas circuit for adjusting the cooling capacity of refrigerant for supplying to an evaporator by mixing low-temperature refrigerant for supplying to the evaporator with a portion of high-temperature refrigerant discharged from a compressor, and wherein the coolant circuit section comprises a heat exchanger for cooling coolant returned from the load to a predetermined temperature by means of the evaporator; and circulating means for supplying the coolant to the load to circulate the coolant.
In accordance with another aspect of the present invention, there is provided an isothermal coolant circulating apparatus comprising a coolant circuit section for cooling coolant returned from a load to a predetermined temperature to supply the coolant to the load, a refrigerating circuit section for cooling the coolant, and a controlling section for controlling the temperature of coolant for supplying to the load, wherein the refrigerating circuit section comprises a hot gas circuit for adjusting the cooling capacity of refrigerant for supplying to an evaporator by mixing low-temperature refrigerant for supplying to the evaporator with a portion
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
SMC Corporation
Tanner Harry B.
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