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Flow rate control valveRelated Patent Categories: Refrigeration, Automatic Control, Refrigeration Producer, Of Or By Evaporation ZoneFlow rate control valve description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060005556, Flow rate control valve. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] This application is a continuing application, filed under 35 U.S.C. .sctn.111(a), of International Application PCT/JP2004/002673, filed Mar. 3, 2004, it being further noted that priority is based upon Japanese Patent Application No. 2003-059353, filed Mar. 6, 2003. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates to a flow rate control valve, and more particularly to a flow rate control valve used as an expansion device in a refrigeration cycle for an automotive air conditioner, which changes high-temperature, high-pressure refrigerant into low-temperature, low-pressure refrigerant to thereby deliver the refrigerant to an evaporator. [0004] 2. Description of the Related Art [0005] When a refrigeration cycle for an automotive air conditioner uses, as a control valve for controlling a compressor, a differential pressure control type that controls the differential pressure across the compressor or suction pressure of the same such that it is substantially constant, it is considered preferable to use, as an expansion device, an expansion valve of a flow rate control type different in control method, so as to stabilize the controllability of the system. A flow rate control valve of this kind has been described e.g. in Japanese Unexamined Patent Publication (Kokai) NO. 2001-153495. [0006] The flow rate control valve includes a constant flow-rate mechanism. The constant flow-rate mechanism is configured based on a principle that if the cross-sectional area of a passage through which refrigerant flows between a refrigerant inlet and a refrigerant outlet and the differential pressure across the passage are determined, the flow rate of refrigerant flowing through the control valve can be controlled to be constant, and hence by varying one of the cross-sectional area and the differential pressure by a solenoid, it is possible to cause refrigerant to flow at a constant flow rate corresponding to a value set by the solenoid. More specifically, the constant flow-rate mechanism includes a flow passage cross-sectional area control valve for controlling the cross-sectional area of the passage, and a constant differential pressure control valve for controlling the differential pressure between the inlet and the outlet of the flow passage cross-sectional area control valve to be substantially constant, and is configured such that the flow passage cross-sectional area of the flow passage cross-sectional area control valve is controlled by the solenoid, to thereby hold the flow rate of refrigerant flowing through the flow rate control valve at a predetermined constant flow rate corresponding to a flow passage cross-sectional area set by the solenoid (see FIG. 1 in Japanese Unexamined Paten Publication (Kokai) No. 2001-153495). Alternatively, the constant flow-rate mechanism includes a restriction passage the cross-sectional area of which is not changed, and a differential pressure control valve for controlling the differential pressure between the inlet and the outlet of the restriction passage such that it is substantially constant, and is configured such that a differential pressure value set to the differential pressure control valve is controlled by the solenoid to thereby hold the flow rate of refrigerant flowing through the flow rate control valve at a predetermined constant flow rate corresponding to the differential pressure set by the solenoid (see FIG. 2 in Japanese Unexamined Paten Publication (Kokai) No. 2001-153495). [0007] However, to control the flow rate to be constant, the conventional flow rate control valve includes the restriction passage for creating the differential pressure, and the differential pressure control valve for controlling the differential pressure across the restriction passage such that it is constant, and hence suffers from the problem of being complicated in construction. SUMMARY OF THE INVENTION [0008] The present invention has been made in view of these problems, and an object thereof is to provide a flow rate control valve of a constant flow-rate control type, which is simple in construction. [0009] To solve the above problem, the present invention provides a flow rate control valve that controls a flow rate of refrigerant which is throttled and expanded to be delivered to an evaporator, such that the flow rate is substantially constant, comprising a constant differential pressure control valve that controls a differential pressure before and after pressure loss caused by passage of refrigerant through the evaporator, such that the differential pressure is substantially constant. [0010] The above and other objects, features and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate preferred embodiments of the present invention by way of example. BRIEF DESCRIPTION OF THE DRAWINGS [0011] FIG. 1 is a central longitudinal cross-sectional view of the construction of a flow rate control valve according to a first embodiment. [0012] FIG. 2 is a central longitudinal cross-sectional view of the construction of a flow rate control valve according to a second embodiment. [0013] FIG. 3 is an expanded cross-sectional view showing essential components of the flow rate control valve according to the second embodiment. [0014] FIG. 4 is a central longitudinal cross-sectional view of the construction of a flow rate control valve according to a third embodiment of the present invention. [0015] FIG. 5 is a central longitudinal cross-sectional view of the construction of a flow rate control valve according to a fourth embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [0017] FIG. 1 is a central longitudinal cross-sectional view of the construction of a flow rate control valve according to a first embodiment of the present invention. [0018] The flow rate control valve is capable of performing constant flow rate control only after it is connected to an evaporator 1, and has a body block 2 provided with a high-pressure refrigerant inlet 3 to which refrigerant at pressure Po is supplied, a low-pressure refrigerant outlet 4 from which refrigerant is delivered to the evaporator 1 while being expanded, a return refrigerant inlet 5 to which refrigerant is returned from the evaporator 1, and a return refrigerant outlet 6 from which the returned refrigerant is delivered to a compressor. The high-pressure refrigerant inlet 3 has a strainer 7 disposed therein in a manner closing a passage formed therein. [0019] The body block 2 has an upper portion thereof formed with a large-diameter hole, a central portion thereof formed with a cylinder concentric with the large-diameter hole and extending vertically, as viewed in FIG. 1, and a lower portion thereof formed with a hole that communicates with the cylinder formed in the central portion thereof. The hole in the lower portion of the body block 2 is communicated with the return refrigerant inlet 5 and the return refrigerant outlet 6, by a return passage 8, and an opening of the hole formed downward of the return passage 8 is closed by a packing pressed against the body block 2 by a screw 10 via a packing retainer 9. [0020] The rim of an upper end of the cylinder formed in the central portion of the body block 2 forms a valve seat 11, and a valve element 12 is disposed in a manner opposed to the valve seat 11 from above, as viewed in FIG. 1, such that the valve element 12 can move to and away from the valve seat 11. The valve element 12 is integrally formed with a piston 13, which serves as a pressure-sensing member axially movably disposed within the cylinder, with a small-diameter shaft connecting between the valve element 12 and the piston 13. In the cylinder, a refrigerant passage communicating with the high-pressure refrigerant inlet 3 opens in a portion where the small-diameter shaft is located. A chamber above the cylinder, formed by the large-diameter hole formed in the upper portion of the body block 2, is communicated with the low-pressure refrigerant outlet 4 via a refrigerant passage. Continue reading about Flow rate control valve... Full patent description for Flow rate control valve Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Flow rate control valve patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Flow rate control valve or other areas of interest. ### Previous Patent Application: Method and apparatus to manage airflow in a chassis Next Patent Application: Vapor compression refrigerator Industry Class: Refrigeration ### FreshPatents.com Support Thank you for viewing the Flow rate control valve patent info. IP-related news and info Results in 0.1547 seconds Other interesting Feshpatents.com categories: Tyco , Unilever , Warner-lambert , 3m 174 |
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