Refrigeration – Automatic control – Refrigeration producer
Reexamination Certificate
1999-07-06
2001-02-20
McDermott, Corrine (Department: 3743)
Refrigeration
Automatic control
Refrigeration producer
Reexamination Certificate
active
06189326
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application is based upon and claims priority from Japanese Patent Application Nos. Hei 10-192069, filed Jul. 7, 1998, and Hei 11-31776, filed Feb. 9, 1999, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pressure control valve which controls a refrigerant pressure at an outlet side of a radiator based on a refrigerant temperature at the outlet side of the radiator, and it is preferably applicable to a vapor compression type refrigeration cycle in which carbon dioxide (CO
2
) is used as a refrigerant.
2. Description of Related Art
Hitherto, there has been known means for attempting to improve a refrigeration performance by means of lowering enthalpy of the refrigerant at an inlet side of an evaporator by performing heat exchange between the refrigerant at an outlet side of the evaporator and that at the outlet side of the radiator.
Furthermore, as a control valve for adjusting a valve port based on the refrigerant temperature at the outlet side of the radiator, there has been known an invention disclosed in Japanese Patent Application Laid-Open No. Shou 55-54777.
According to the control valve disclosed in the above prior art, since a temperature sensing portion for sensing the refrigerant temperature at the outlet side of the radiator and the valve port whose opening degree is to be adjusted according to an internal pressure of the temperature sensing portion are provided in the same flow passage in series, there is a problem that the refrigeration performance cannot be improved by the aforementioned means.
In order to solve this problem, as disclosed in Japanese Patent Application Laid-Open No. Hei 5-203291, there is considered means in which the temperature sensing portion is made into a temperature sensing cylinder using a capillary tube to detect the refrigerant temperature at the outlet side of the radiator. However, in this means, since a heat sensed by the temperature sensing cylinder transmits to a control chamber at a diaphragm side through the capillary tube, the temperature change in the control chamber is lagged with respect to a refrigerant temperature change at the outlet side of the radiator. Therefore, by this means, a response characteristic of the control valve with respect to the refrigerant temperature change at the outlet side of the radiator (hereafter, this response characteristic is referred to as temperature response characteristic) is compromised, so that it is impossible to suitably control the refrigeration cycle.
Further, since it is necessary to assemble the capillary tube and the temperature sensing cylinder to the outlet side of the radiator, the manufacturing processes for the refrigeration cycle is increased.
SUMMARY OF THE INVENTION
The present invention is made in light of the above-mentioned problems, and it is an object of the present invention to provide a pressure control valve suitable for the refrigeration cycle having a heat exchanger for performing heat exchange between the refrigerant at the outlet side of the evaporator and that at the outlet side of the radiator.
According to a pressure control valve of the present invention, a temperature sensing portion is located in a casing for accommodating a control valve main body, and a temperature sensing chamber communicating with an inlet side of a heat exchanger and an introduction passage for introducing a refrigerant flowing from the heat exchanger to an upstream side of a valve port in a refrigerant flow are formed in the casing.
Accordingly, it is possible to reduce a lag of temperature change in the temperature sensing portion with respect to a refrigeration temperature change at an outlet side of a radiator in comparison with means for sensing a refrigerant temperature at the outlet side of the radiator by, as described in Japanese Patent Application Laid-Open No. 5-203291, making the temperature sensing portion into the temperature sensing cylinder using the capillary tube.
Therefore, since it is possible to improve the temperature response characteristic of a pressure control valve, the refrigeration cycle can be suitably controlled.
Further, since it is not necessary to assemble the capillary tube and the temperature sensing cylinder to the outlet side of the radiator like Japanese Patent Application Laid-Open No. 5-203291, it is possible to reduce the number of processes for assembling the refrigeration cycle (the number of manufacturing processes), so that it is possible to attempt to reduce a manufacturing prime cost of the refrigeration cycle.
As described above, by the pressure control valve according to the present invention, it is possible to suitably control the refrigeration cycle while attempting to reduce a manufacturing prime cost of the refrigeration cycle.
According to another aspect of the present invention, the pressure control valve includes: a casing in which there are formed a first passage for communicating an outlet side of a radiator with an inlet side of a heat exchanger, and a second passage for introducing a refrigerant flowing from the heat exchanger to an upstream side of a valve port in a refrigerant flow; a temperature sensing portion whose internal pressure changes according to a temperature of the refrigerant flowing through the first passage; and a valve body which penetrates through a separation portion for separating the first and second passages and adjusts an opening degree of the valve port by mechanically interlocking with an internal pressure change of the temperature sensing portion.
Accordingly, it is possible to suitably control the refrigeration cycle while attempting to reduce a manufacturing prime cost of the refrigeration cycle.
Further, according to another aspect of the present invention, the heat sensing portion is prevented from being cooled by providing heat insulating members for preventing a heat transfer between the temperature sensing portion and the second passage, so that it is possible to surely control the refrigerant pressure at the outlet side of the radiator.
Furthermore, according another aspect of the present invention, the heat sensing portion is prevented from being cooled by providing a passage for allowing a part of the refrigerant flowing through the first passage to flow to the second passage, so that it is possible to surely control the refrigerant pressure at the outlet side of the radiator.
REFERENCES:
patent: 3638446 (1972-02-01), Palmer
patent: 5245836 (1993-09-01), Lorentzen et al.
patent: 5890370 (1999-04-01), Sakakibara et al.
patent: 6044655 (2000-04-01), Ozaki et al.
patent: 0 438 625-A2 (1991-07-01), None
patent: 0 786 632-A2 (1997-07-01), None
patent: 0 837 291-A2 (1998-04-01), None
Ise Sadatake
Tomatsu Yoshitaka
Ali Mohammad M
Denso Corporation
Harness Dickey & Pierce PLC
McDermott Corrine
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