Expansion valve and refrigeration cycle

Details Expansion valve and refrigeration cycle Expansion valve and refrigeration cycle

2003-03-26

2004-07-06

Tapolcai, William E. (Department: 3754)

Refrigeration

Automatic control

Refrigeration producer

C236S09200D, C251S359000

Reexamination Certificate

active

06758055

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to an expansion valve and a refrigeration cycle for use in an air conditioner of a car, a refrigerating display case, or the like.
DESCRIPTION OF THE RELATED ART
There are various types of expansion valves, and a widely used expansion valve comprises an orifice formed by narrowing a portion of a high-pressure refrigerant path through which high-pressure refrigerant traveling to an evaporator passes, and a valve member disposed upstream of and opposing to the orifice, the valve member moved to open and close the valve in response to the temperature and pressure of a low-pressure refrigerant sent out from the evaporator.
One example of this type of expansion valves is disclosed in Japanese Patent Laid-Open No. 8-334280 regarding an expansion valve used in a refrigeration cycle of an air conditioner of a car.
That is, as illustrated in
FIG. 3
, a refrigeration cycle
1
comprises a compressor
2
driven by an engine, a condenser
3
connected to the output side of the compressor
2
, a liquid tank
4
connected to the condenser, an expansion valve
5
for expanding the liquid-phase refrigerant from the liquid tank
4
into a two-phase refrigerant of vapor and liquid, and an evaporator
6
connected to the expansion valve
5
.
The expansion valve
5
comprises an expansion valve body
5
a
provided with a high-pressure-side path
5
b
through which liquid-phase refrigerant travels and a low-pressure-side path
5
c
through which two-phase refrigerant of vapor and liquid travels, wherein the high-pressure-side path
5
b
and the low-pressure-side path
5
c
are communicated via an orifice
7
. Further, a valve member
8
that adjusts the amount of refrigerant passing through the orifice
7
is equipped in a valve chamber
8
d.
In the expansion valve
5
, a low-pressure refrigerant path
5
d
is formed to pass through the expansion valve body
5
a
, and in the low-pressure refrigerant path
5
a
is disposed an actuating rod
9
a
in a slidable manner, the actuating rod
9
a
being driven by a power element portion
9
fixed to the upper portion of the expansion valve body
5
a
. The interior space of the power element portion
9
is divided by a diaphragm
9
d
into an upper airtight chamber
9
c
and a lower airtight chamber
9
c
′. A disc portion
9
e
disposed at the upper end of the actuating rod
9
a
comes into contact with the diaphragm
9
d
. In the power element portion
9
, an upper lid
9
f
is provided with a tube connecting hole
9
g
formed to the center portion thereof, and a capillary tube
9
h
is mounted to the tube connecting hole
9
g.
Furthermore, at the lower portion of the expansion valve body
5
a
, a compression coil spring
8
a
pressurizing via a support member
8
c
the valve member
8
toward its valve closing direction is disposed within the valve chamber
8
d
. The valve chamber
8
d
is defined by the expansion valve body
5
a
and an adjustment screw
8
b
screwed onto the expansion valve body
5
a
through the seal of an O-ring
8
e
. An actuating rod
9
b
attached to the lower end of the actuating rod
9
a
moves the valve member
8
toward the valve opening direction by the sliding movement of the actuating rod
9
a.
The actuating rod
9
a
in the power element portion
9
transmits the temperature of the low-pressure refrigerant path
5
d
to the upper airtight chamber
9
c
, and in correspondence to the transmitted temperature, the pressure within the upper airtight chamber
9
c
changes. For example, if the temperature is high, the pressure within the upper airtight chamber
9
c
rises so that the diaphragm
9
d
pushes down the actuating rod
9
a
, the movement of which drives the valve member
8
in the direction opening the valve. Thus, the amount of refrigerant passing through the orifice
7
increases, and the temperature of the evaporator
6
is thereby reduced.
On the other hand, if the temperature is low, the pressure within the upper airtight chamber
9
c
falls so that the force of the diaphragm
9
d
pushing down the actuating rod
9
a
weakens, and the valve member
8
moves in the direction closing the valve by the force of the compression coil spring
8
a
biasing the member
8
in the valve closing direction. Thus, the amount of refrigerant passing through the orifice
7
decreases, and the temperature of the evaporator
6
is thereby increased.
Thus, the expansion valve
5
moves the valve member
8
according to the change in temperature of the low-pressure refrigerant path
5
d
to thereby change the opening of the orifice
7
, adjusting the amount of refrigerant passing through the orifice and thus controlling the temperature of the evaporator
6
. Thus, in this type of expansion valve
5
, the opening area of the orifice
7
for realizing adiabatic expansion of the liquid-phase refrigerant to two-phase refrigerant is determined by adjusting via the adjustment screw
8
b
the spring load of the compression coil spring
8
a
having a variable spring load that pressurizes the valve member
8
toward the direction closing the valve.
FIG. 3
illustrates an example of the expansion valve
5
wherein a capillary tube
9
h
is mounted on the tube mounting hole
9
g
of the power element portion
9
.
FIG. 4
illustrates an alternative example comprising a sealing plug
9
i
provided instead of the capillary tube
9
h
on the tube mounting hole
9
g
, an expansion valve body
5
a
having a rectangular column form, a thin portion
5
e
formed at the bottom of both side portions of the body, and bolt holes
5
f
created to the body near the low-pressure refrigerant passage
5
d.
FIG. 5
is a vertical cross-sectional view showing another prior-art example of the expansion valve illustrated with a refrigerant cycle
1
, with the construction of the heat sensing shaft varied from the example shown in FIG.
3
. An expansion valve
101
illustrated in
FIG. 5
comprises a valve body
30
similar to the valve body of the prior art example illustrated in
FIG. 3
, having a high-pressure-side path
32
c
through which high-pressure refrigerant flowing toward an evaporator
6
travels, a low-pressure-side path
32
b
, an orifice
32
a
disposed between the paths
32
c
and
32
b
, a spherical valve member
32
d
disposed to oppose to the orifice
32
a
from the upstream side of the refrigerant, a bias means
32
e
for biasing the valve member toward the orifice from the upstream side, a valve component
32
f
disposed between the bias means and the valve member for transmitting the biasing force of the bias means to the valve member
32
d
, a power element portion
36
that operates in connection with the temperature of a low-pressure refrigerant exiting the evaporator
6
, and a heat sensing drive rod
318
having a heat sensing rod and an actuating rod integrally formed and disposed between the power element portion and the valve member, wherein the movement of the power element portion
36
drives the valve member
32
d
to move toward or away from the orifice
32
a
to thereby control the flow of refrigerant passing through the orifice.
The power element portion
36
comprises a diaphragm
36
a
made of a metallic thin plate having flexibility such as stainless steel, an upper cover
36
d
and a lower cover
36
h
made of stainless steel constituting an airtight wall sandwiching the diaphragm
36
a
and defining two pressure chambers, an upper pressure chamber
36
b
and a lower pressure chamber
36
c
, divided by the diaphragm
36
a
, and a hole cap
36
i
for filling a refrigerant into the upper pressure chamber
36
b
as a diaphragm driving medium. The lower pressure chamber
36
c
is communicated to a second path
34
via a pressure equalizing hole
36
e
which is formed concentrically with the center line of the orifice
32
a
. A refrigerant vapor exiting the evaporator
6
travels through the second path
34
, by which the path
34
functions as a gas-phase refrigerant path, and the pressure of the gas-phase refrigerant is loaded on the lower pressure chamber
36
c
thr

Affiliated with

Also associated with

Rating

Expansion valve and refrigeration cycle does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Expansion valve and refrigeration cycle, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Expansion valve and refrigeration cycle will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3205237