Refrigeration – Refrigeration producer – Evaporator – e.g. – heat exchanger
Reexamination Certificate
2000-06-06
2001-11-13
Tapolcai, William E. (Department: 3744)
Refrigeration
Refrigeration producer
Evaporator, e.g., heat exchanger
C137S543230
Reexamination Certificate
active
06314753
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
In refrigerating cycles so-called thermostatic expansion valves are widely used. Thermostatic expansion valves are designed to control the flow rate of the refrigerant being introduced into an evaporator in accordance with the temperature and pressure of the low-pressure refrigerant exiting the evaporator.
Another possibility to control the flow rate of the refrigerant flowing into the evaporator is to use a so-called supercooling degree-controlled expansion valve, which in contrast to said thermostatic expansion valve detects and controls the degree of supercooling of the high-pressure refrigerant supplied to the evaporator. A supercooling degree-controlled expansion valve performs all required operations at the inlet side of the evaporator without needing any thermostatic equipment or additional temperature or pressure transmitting passages. This is advantageous because a supercooling degree-controlled expansion valve can be made extremely compact.
2. Description of the Related Art
In a supercooling degree-controlled expansion valve disclosed in U.S. Pat. No. 4,324,112 for example, the valve seat is arranged in a high-pressure refrigerant passage through which the refrigerant is supplied to the evaporator and at a location of an upstream side of a restricted portion formed by narrowing an intermediate portion of the refrigerant passage. The valve element for opening and closing the refrigerant passage faces the valve seat and is urged towards the valve seat by urging means from a downstream side. This valve type is structurally simple and compact and yet is capable of controlling the degree of supercooling of the high-pressure refrigerant at a constant level. However, in said known supercooling degree-controlled expansion valves the valve element freely vibrates due to the refrigerant flow and repeatedly collides against its surrounding member thus producing noise.
In high-pressure hydraulic applications it is known to equip, e.g., a relief valve element with a damping piston received in a cylinder chamber to suppress valve rattling. However, supercooling degree-controlled expansion valves need to operate reliably, extremely sensitive and in an environment (most often in the motor compartment of a vehicle) where permanently external vibration and considerable temperature changes occur. For this reason it was believed that the performance of such supercooling degree-controlled expansion valves would unduly suffer when implementing any vibration attenuating measures.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the invention to provide a structurally simple noiseless, silent supercooling degree-controlled expansion valve in which vibrations of the valve element induced by the refrigerant flow are suppressed sufficiently without deteriorating the valve performance, i.e. without harming the capacity of the valve to control an essential constant degree of supercooling.
Since the urging means in the supercooling degree-controlled expansion valve is pressing the valve element in an oblique direction inclined with respect to the axial direction of said valve element against a surrounding member or the surrounding when said valve member is moving in relation to said valve seat, noise is prevented from being produced as soon as the valve element has the tendency to collide during vibration under the influence of the refrigerant flow, etc. with its surrounding. Alternatively, a liquid damper using the refrigerant as a vibration absorbing material is coupled to the valve element to restrict vibrations of the valve element. A silent, high-quality supercooling degree-controlled expansion valve can be achieved.
A particular simple structure of said expansion valve with a vibration safe valve element is achieved by determining the mechanical co-operation between the compression coil spring and the valve member such that the compression coil spring maintains the valve element during its motions in contact with the lateral surroundings. This either is achieved by a protruding spring turn end contacting the valve element offset to its longitudinal axis or by arranging the active compression coil spring end portion laterally offset with respect to the longitudinal axis of the valve element. Said predetermined co-operation suppresses particularly lateral vibrations of the valve element, because this is maintained in contact with the lateral surroundings while moving in relation to the valve seat, advantageously, said measure does not lead to any detrimental effect on the valve performance.
When alternatively coupling the valve element with a liquid damper the refrigerant efficiently can be used to absorb vibrations of the valve element, particularly axial vibrations. The motion of the valve element during operation of the expansion valve sucks in or pumps out refrigerant into or from the cylinder chamber and through a narrow gap. The flow through said narrow gap is restricted and thus suppresses the vibration.
REFERENCES:
patent: 2960998 (1960-11-01), Sinker et al.
patent: 3559678 (1971-02-01), Donner
patent: 3565100 (1971-02-01), Pfleger
patent: 4009592 (1977-03-01), Boerger
patent: 4324112 (1982-04-01), Fujiwara et al.
patent: 4951478 (1990-08-01), McDonald
patent: 4953589 (1990-09-01), Nakamura
patent: 5170638 (1992-12-01), Koenig et al.
Hirota Hisatoshi
Inoue Yusuke
Tsugawa Tokumi
Nilles & Nilles SC
Tapolcai William E.
TGK Co. Ltd.
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