Fluid handling – Line condition change responsive valves – Direct response valves
Reexamination Certificate
2002-03-28
2004-11-23
Krishnamurthy, Ramesh (Department: 3753)
Fluid handling
Line condition change responsive valves
Direct response valves
C137S512100, C137S855000, C137S857000, C417S569000
Reexamination Certificate
active
06820644
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a delivery valve device for a refrigerant compressor.
DISCUSSION OF THE BACKGROUND
Refrigerant compressors of various types, for example reciprocating or rotary compressors, are known, particularly hermetically sealed motor-driven compressors for domestic or commercial refrigeration and air conditioning. All these compressors have the function of compressing a refrigerant fluid.
The general principle of such compressors is illustrated in
FIG. 1
, which schematically depicts, in a cylinder, a piston
19
, a valve plate
11
and a cylinder head comprising two chambers
16
and
18
. The walls of the cylinder, the piston
19
and the valve plate
11
delimit a compression/expansion chamber
15
. The valve plate
11
has an intake passage
110
, between the compression/expansion chamber
15
and the intake chamber
16
, and a delivery passage
111
between the chamber
15
and the delivery chamber
18
. An intake valve
12
is positioned on the valve plate
11
and pressed against it. During the intake phase, the valve
12
opens under the effect of the pressure difference between the compression/expansion chamber
15
, which increases in volume because of the retreating movement of the piston (here assumed to be of the reciprocating type), and the intake chamber
16
. The movement of the intake valve is limited by a stop
17
. At the end of the intake phase, the valve
12
closes again against the valve plate, sealing the passage
110
against fluid when compression begins.
A delivery valve
13
is positioned on the valve plate
11
and pressed against it. It is generally built in at one end and free at the other end. During the delivery
Phase, the valve
13
opens under the effect of the pressure difference between the chamber
15
, where the fluid is compressed under the effect of the piston
19
, and the delivery chamber
18
. The movement of the delivery valve
13
is limited by a delivery vave stop
14
against which the valve
13
comes into contact. At the end of the delivery phase, the delivery valve
13
closes again against the valve plate
11
, sealing against the reflux of the fluid through the passage
111
.
In fact, it is found that the operation of the valves explained herein above is more complicated than that. In particular, the intake and delivery valves generally open several times during a given phase in the cycle and experience a fluttering movement between the valve plate and the stop. This flutter leads to metal-to-metal impact which generates noise and greatly increases the noise level of the compressor, particularly as far as the delivery valve is concerned.
A valve device of this type is described for example in American patent U.S. Pat. No. 5,110,272. Therein can be found all the elements described above. The problem that this device sets out to solve is that of giving the delivery valves sufficient flexibility while at the same time keeping its axial bulk to an acceptable level. This is achieved by providing a L-shaped valve. However, this valve lifts a great way off the valve plate when it opens, and is therefore subject to the flutter described above and to the ensuing disadvantages.
The object of the invention is to appreciably reduce the noise level of the compressor by limiting the impact due to the delivery valve.
SUMMARY OF THE INVENTION
The subject of the invention is therefore a delivery valve device which overcomes the drawbacks described herein above by virtue of a modification to the a principle of the valve on the delivery side which consists in keeping the delivery valve in constant contact, at both ends, with the valve plate.
According to the invention, there is therefore provided a delivery valve device for a refrigerant compressor of the type comprising a valve plate pierced with at least one fluid delivery passage, at least one delivery valve closing said passage on the downstream side in the direction of delivery of the fluid, and secured, at one of its ends, to the valve plate by first fixing the means and at least one delivery valve stop, said device being characterized in that said delivery valve is secured, at one of its ends, to the valve plate by first fixing means and is held at its other end, in almost permanent sliding contact with the valve plate by a spring secured to the valve plate by second fixing means.
By virtue of the fact that the valve stressing spring allows it to slide but not to lift off the valve plate, there is no bounce and flutter of the valve, hence reducing the noise level.
Another important advantage of the device according to the invention is the increase in the refrigeration capacity of the compressor, for the same cylinder capacity, through the limiting of the effects of delayed closure of the delivery valve.
REFERENCES:
patent: 1707306 (1929-04-01), Holdsworth
patent: 2021085 (1935-11-01), Orr
patent: 2161769 (1939-06-01), Trask
patent: 2908287 (1959-10-01), Augustin
patent: 2970608 (1961-02-01), Doeg
patent: 3751915 (1973-08-01), Ranft et al.
patent: 3811468 (1974-05-01), Bellmer
patent: 4257457 (1981-03-01), Namura et al.
patent: 4410006 (1983-10-01), Moulton
patent: 4507059 (1985-03-01), Kobayashi et al.
patent: 4628963 (1986-12-01), Ishijima et al.
patent: 5110272 (1992-05-01), Andrione et al.
patent: 5558508 (1996-09-01), Sasano et al.
patent: 5887622 (1999-03-01), Ahn
patent: 6012489 (2000-01-01), Rene et al.
patent: 195 04 267 (1996-04-01), None
Krishnamurthy Ramesh
Tecumseh Europe S.A.
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