Expansion valve

Details Expansion valve Expansion valve

1999-08-05

2001-02-20

Tapolcai, William E. (Department: 3744)

Automatic temperature and humidity regulation

Thermostatic

With pressure control

C062S225000

Reexamination Certificate

active

06189800

ABSTRACT:

TECHNICAL FIELD OF THE INVENTION
The present invention relates to expansion valves and, more particularly, to expansion valves used for refrigerant utilized in refrigeration cycles of air conditioner, refrigeration device and the like.
BACKGROUND OF THE INVENTION
In the prior art, these kinds of expansion valves were used in refrigeration cycles of air conditioners in automobiles and the like.
FIG. 9
shows a prior art expansion valve in cross-section together with an explanatory view of the refrigeration cycle. The expansion valve
10
includes a valve body
30
formed of prismatic-shaped aluminum comprising a refrigerant duct
11
of the refrigeration cycle having a first path
32
and a second path
34
, the one path placed above the other with a distance inbetween. The first path
32
is for a liquid-phase refrigerant passing through a refrigerant exit of a condenser
5
through a receiver
6
to a refrigerant entrance of an evaporator
8
. The second path
34
is for a liquid-phase refrigerant passing through the refrigerant exit of the evaporator
8
toward a refrigerant entrance of a compressor
4
.
An orifice
32
a
for the adiabatic expansion of the liquid refrigerant supplied from the refrigerant exit of the receiver
6
is formed on the first path
32
, and the first path
32
is connected to the entrance of the evaporator
8
via the orifice
32
a
and a path
321
. The orifice
32
a
has a center line extending along the longitudinal axis of the valve body
30
. A valve seat is formed on the entrance of the orifice
32
a,
and a valve means
32
b
supported by a valve member
32
c
and forming a valve structure together with the valve seat is included thereto. The valve means
32
b
and the valve member
32
c
are welded and fixed together. The valve member
32
c
is fixed onto the valve means
32
b
and is also forced by a spring means
32
d,
for example, a compression coil spring.
The first path
32
where the liquid refrigerant from receiver
6
is introduced is a path of the liquid refrigerant, and is equipped with an entrance port
321
and a valve room
35
connected thereto. The valve room
35
is a room with a floor portion formed on the same axis of the center line of the orifice
32
a,
and is sealed by a plug
39
.
Further, in order to supply drive force to the valve body
32
b
according to an exit temperature of the evaporator
8
, a small hole
37
and a large hole
38
having a greater diameter than the small are hole
37
formed on said center line axis perforating through the second path
34
. A screw hole
361
for fixing a power element member
36
working as a heat sensor is formed on the upper end of the valve body
30
.
The power element member
36
is comprised of a stainless steel diaphragm
36
a,
an upper cover
36
d,
and a lower cover
36
h,
each defining an upper pressure activate chamber
36
b
and a lower pressure activate chamber
36
c
divided by said diaphragm and forming two sealed chambers above and under the diaphragm
36
a,
and a tube
36
i
for enclosing a predetermined refrigerant working as a diaphragm driver liquid into said upper pressure activate chamber, and is fixed to the valve body
30
by a screw
361
. Said lower pressure activate chamber
36
c
is connected to said second path
34
via a pressure hole
36
e
formed to have the same center as the center line axis of the orifice
32
a.
A refrigerant vapor from the evaporator
8
is flown through the second path
34
. The second path
34
is a path for gas phase refrigerant, and the pressure of said refrigerant vapor is added to said lower pressure activate chamber
36
c
via the pressure hole
36
e.
Further, inside the lower pressure activate chamber
36
c
is a heat sensing shaft
36
f
made of aluminum and an activating shaft
37
f
made of stainless steel. The heat sensing shaft
36
f
exposed horizontally inside the second path
34
is movably positioned through the second path
34
inside the large hole
38
and contacts the diaphragm
36
a
so as to transmit the refrigerant exit temperature of the evaporator
8
to the lower pressure activate chamber
36
c,
and to provide a driving force in response to the displacement of the diaphragm
36
a
according to the pressure difference between the upper pressure activate chamber
36
b
and the lower pressure activate chamber
36
c
by moving inside the large hole
38
. The activating shaft
37
f
is movably positioned inside the small hole
37
and provides pressure to the valve means
32
b
against the spring force of the spring means
32
d
according to the displacement of the heat sensing shaft
36
f.
The heat sensing shaft
36
f
comprises a stopper portion
312
having a large radius and works as a receiving member of the diaphragm
36
a,
the diaphragm
36
a
positioned to contact its surface, a large radius portion
314
contacting the lower surface of the stopper portion
312
at one end surface and being moveably inserted inside the lower pressure activate chamber
36
c,
and a heat sensing portion
318
contacting the other end surface of said large radius portion
314
at one end surface and having the other end surface connected to the activating shaft
37
f.
Further, the heat sensing shaft
36
f
is equipped with an annular sealing member, for example, an o-ring
36
g,
for securing the seal of the first path
32
and the second path
34
. The heat sensing shaft
36
f
and the activating shaft
37
f
are positioned so as to contact each other, and activating shaft
37
f
also contacts the valve means
32
b.
The heat sensing shaft
36
f
and the activating shaft
37
f
form a valve driving shaft together. Therefore, the valve driving shaft extending from the lower surface of the diaphragm
36
a
to the orifice
32
a
of the first path
32
is positioned having the same center axis in the pressure hole
36
e.
Further, the heat sensing shaft
36
f
and the activating shaft
37
f
could be formed as one, with the heat sensing shaft
36
f
being extended so as to contact the valve means
32
b.
Still further, a plug body could be used instead of the tube
36
i
for sealing the predetermined refrigerant.
A known diaphragm driving liquid is filled inside the upper pressure activating chamber
36
b
placed above a pressure activate housing
36
d,
and the heat of the refrigerant vapor from the refrigerant exit of the evaporator
8
flowing through the second path
34
via the diaphragm
36
a
is transmitted to the diaphragm driving liquid.
The diaphragm driving liquid inside the upper pressure activate chamber
36
b
adds pressure to the upper surface of the diaphragm
36
a
by turning into gas in correspondence to said heat transmitted thereto. The diaphragm
36
a
is displaced in the upper and lower direction according to the difference between the pressure of the diaphragm driving gas added to the upper surface thereto and the pressure added to the lower surface thereto.
The displacement of the center portion of the diaphragm
36
a
to the upper and lower directions is transmitted to the valve member
32
b
via the valve member driving shaft and moves the valve member
32
b
close to or away from the valve seat of the orifice
32
a.
As a result, the refrigerant flow rate is controlled.
That is, the gas phase refrigerant temperature of the exit side of the evaporator
8
is transmitted to the upper pressure activate chamber
36
b,
and according to said temperature, the pressure inside the upper pressure activate chamber
36
b
changes, and the exit temperature of the evaporator
8
rises. When the heat load of the evaporator rises, the pressure inside the upper pressure activate chamber
36
b
rises, and accordingly. the heat sensing shaft
36
f
or valve member driving shaft is moved to the downward direction and pushes down the valve means
32
b
via the activating shaft
37
, resulting in a wider opening of the orifice
32
a.
This increases the supply rate of the refrigerant to the evaporator, and lowers the temperature of the evaporator
8
. In reverse, when the exit temperature of the evapo

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