Refrigeration – Automatic control – Refrigeration producer
Reexamination Certificate
2002-09-30
2004-01-06
Tapolcal, William E. (Department: 3744)
Refrigeration
Automatic control
Refrigeration producer
C062S468000, C251S031000
Reexamination Certificate
active
06672088
ABSTRACT:
TECHNICAL FIELD
This invention relates to a self-operated regulating valve, and a compression refrigerating machine having it.
BACKGROUND ART
FIG. 9
is a system diagram showing a multistage compression turbo-refrigerating machine according to prior art. As shown in the drawing, in an evaporator
1
, a refrigerant liquid (e.g., an organic refrigerant such as a fluorocarbon) is heated with cold water (or brine)
3
, flowing in a tube
2
, to generate a refrigerant gas. At this time, the cold water
3
is cooled by heat exchange in the evaporator
1
, and then delivered to the outside.
A turbo-compressor
4
having two impellers takes in the refrigerant gas evaporated by the evaporator
1
, compresses it at two stages by the two impellers rotated by an electric motor (not shown), and discharges a high temperature, high pressure refrigerant gas. A refrigerant gas from an inter-cooler
5
is also taken into the impeller located at the second stage (intermediate stage). In a condenser
6
, the high temperature, high pressure refrigerant gas discharged from the turbo-compressor
4
is cooled with cooling water
8
, flowing in a tube
7
, to condensate and liquefy it. At this time, the cooling water
8
is heated by heat exchange in the condenser
6
, and then discharged to the outside. A refrigerant liquid formed by condensation is accumulated at the bottom of the condenser
6
.
The inter-cooler
5
evaporates part of a refrigerant supplied from the condenser
6
, and allows the resulting refrigerant gas to be taken into the second stage of the turbo-compressor
4
via a pipe line
10
. Then, the refrigerant gas is compressed by the second-stage impeller to increase latent heat. That is, in the inter-cooler
5
, the refrigerant liquid fed from the condenser
6
is reduced in pressure by a first-stage orifice to an intermediate pressure to expand it, converting it into a refrigerant gas partly. This refrigerant gas, as stated above, is taken into (intermediately sucked into) the second-stage impeller of the turbo-compressor
4
. On the other hand, the remaining refrigerant liquid cooled upon evaporation of the refrigerant liquid is further reduced in pressure by a second-stage orifice, and then fed into the evaporator
1
. Simultaneously, the inter-cooler
5
has the function of retaining a constant pressure difference between the condenser
6
and the evaporator
1
. For this purpose, an intermediate suction valve
9
is put into the pipe line
10
to regulate the flow rate of the refrigerant gas supplied into the turbo-compressor
4
via the pipe line
10
. Concretely, the internal pressure P
1
of the condenser
6
and the internal pressure P
2
of the evaporator
1
are detected, and a pressure switch is activated on condition that a differential pressure, &Dgr;P, between the two pressures exceeds a set value. Upon activation of the pressure switch, an electromagnetic valve or an electric valve is opened. Whereas the valve is closed when the differential pressure is not more than the set value. That is, the above-described intermediate suction valve
9
according to the prior art is constituted as a valve comprising the pressure switch and the electromagnetic or electric valve integrated.
With the turbo-refrigerating machine according to the prior art, a valve comprising a pressure switch and an electromagnetic or electric valve integrated is used as the intermediate suction valve
9
for maintaining the pressure difference between the internal pressure of the evaporator
1
and the internal pressure of the condenser
6
at a constant value. Thus, the intermediate suction valve
9
itself is large in size and expensive. The cost of the turbo-refrigerating machine is boosted accordingly.
With the turbo-refrigerating machine, moreover, there are generally other cases, in addition to the above-mentioned case, in which the flow rate of a fluid, such as a refrigerant, needs to be adjusted in accordance with the differential pressure between one of the pressures, P
1
, and the other pressure, P
2
, i.e., &Dgr;P (=P
1
−P
2
).
The present invention has been accomplished in light of the above-described prior art, and its object is to provide a self-operated regulating valve, and a compression refrigerating machine having it, which are capable of autonomously opening or closing a valve for flowing a fluid, such as a refrigerant, with the use of a low cost, simple configuration in accordance with a differential pressure between a pressure at one site and a pressure at another site.
DISCLOSURE OF THE INVENTION
A first invention for attaining the above object is a self-operated regulating valve characterized in that one pressure introduced into one pressure transmission chamber, which is a space formed between a cylindrical valve body and one end surface of a spool formed axially movably in an internal space of the valve body, acts on the one end surface of the spool; other pressure introduced into other pressure transmission chamber, which is a space formed between the valve body and the other end surface of the spool, and a spring force of a preload spring acts on the other end surface of the spool; and a through-hole is provided in the spool, whereby when a difference between the one pressure and the other pressure exceeds a set value, the through-hole and pipe lines connected to the valve body communicate to bring the self-operated regulating valve into an open state, while when the difference does not exceed the set value, the through-hole and the pipe lines are cut off to bring the self-operated regulating valve into a closed state.
According to this invention, the valve can be opened or closed according to the differential pressure between the one pressure and the other pressure. Consequently, a simple-structured inexpensive valve can be supplied.
A second invention is a self-operated regulating valve characterized in that one pressure introduced into one pressure transmission chamber, which is a space formed between a cylindrical valve body and a flange portion provided midway through a spool, acts on the flange portion of the spool; other pressure introduced into other pressure transmission chamber, which is a space formed between the valve body and one end surface of the spool formed axially movably in an internal space of the valve body, acts on the one end surface of the spool; and the spool moves according to a differential pressure between the one pressure and the other pressure, whereby the other end surface of the spool closes or opens a region between opening ends of two pipe lines connected to the valve body.
According to this invention, like the first invention, the valve can be automatically opened or closed according to the differential pressure between the one pressure and the other pressure. At this time, the region between the opening ends of the two pipe lines connected to the valve body is closed or opened by the other end surface of the spool in accordance with the movement of the spool. Thus, sealability at this site can be maintained more satisfactorily. Consequently, a simple-structured inexpensive valve can be supplied, with sealability of the opening/closing portion being further improved.
A third invention is a self-operated regulating valve characterized in that a pressure of a fluid controlled by the self-operated regulating valve acts, as one pressure, on one end surface of a spool formed axially movably in an internal space of a cylindrical valve body; other pressure introduced into a pressure transmission chamber, which is a space formed between the valve body and the other end surface of the spool, and a spring force of a preload spring acts on the other end surface of the spool; and a through-hole is provided in the spool, whereby when a difference between the one pressure and the other pressure exceeds a set value, the through-hole and pipe lines connected to the valve body communicate to bring the self-operated regulating valve into an open state, while when the difference does not exceed the set value, the through-hole and the pipe line
Ali Mohammad M.
Mitsubishi Heavy Industries Ltd.
Tapolcal William E.
LandOfFree
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