Fluid handling – Systems – Multi-way valve unit
Reexamination Certificate
2002-07-31
2004-12-14
Fox, John (Department: 3753)
Fluid handling
Systems
Multi-way valve unit
C251S059000
Reexamination Certificate
active
06830073
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a four-way reversing valve which is one of direction control valves to control the direction of flow of liquid in a hydraulic or pneumatic circuit and is used, for example, to change the flow of coolant when a cooling or heating operation is selected in a heat pump air conditioning system for a double use of cooling and heating, and particularly, is configured as a solenoid hydraulic operating type using an inner pilot method by incorporating a solenoid-controlled pilot-operated valve and a vane type spool valve which is operated by pilot hydraulic pressure of the solenoid-controlled pilot-operated valve.
2. Description of the Related Art
A heat pump air conditioning system for a double use of cooling and heating uses a heat transfer mechanism performed during a cycle formed of compression, condensation, expansion, and evaporation of coolant and generates cold or hot air flow needed for cooling or heating through heat exchange between the condensation and evaporation steps. Theoretically, the cooling operation or heating operation in such a system could be selected by switching the position of heat exchangers (a condenser and an evaporator) used in the condensation and evaporation steps, respectively. However, switching the positions of the condenser and the evaporator is practically impossible. Thus, the flow of coolant with respect to the condenser and evaporator is changed by using a four-way reversing valve that is one of direction control valves.
A conventional four-way reversing valve used for the cooling/heating operation of a heat pump air conditioning system for a double use of cooling and heating, as shown in
FIG. 1
, is an inner pilot type four-port two-position solenoid-hydraulic operated direction control valve combined with a main valve
10
and a pilot valve
20
. The main valve
10
has four ports and two pilot connection holes located at both left and right ends of the main valve
10
. Four coolant connection pipes
11
,
12
,
13
, and
14
connected to an outlet and an inlet of a compressor and coolant pipes of indoor and outdoor heat exchangers of an air conditioning system are welded at the main valve
10
. Also, the pilot valve
20
is combined with the main valve
10
into an inner pilot type through four capillary pipes
21
,
22
,
23
, and
24
. Reference numeral
27
denotes a solenoid coil for controlling the pilot valve
20
.
FIGS. 2A and 2B
show the conventional four-way reversing valve together with an air conditioning system circuit. Referring to the drawings, the pilot valve
20
combined with the main valve
10
is a four-port two-position spring offset solenoid operated type. A pilot spool
25
is moved to a normal position by a spring
26
and a converting position by an electromagnetic force obtained by exciting the solenoid coil
27
so that one of load ports A and B of the pilot valve
20
is connected to a supply port P while the remaining load port is connected to a drain port R. The exciting current of the solenoid coil
27
is blocked when a cooling operation of an air conditioning system is selected. After a heating operation is selected, the exciting current of the solenoid coil
27
is continuously applied during the operation.
That is, when the cooling operation is selected, the pilot spool
25
is positioned at the normal position as shown in FIG.
2
A. Here, pilot pressure in a chamber
15
at one side of the main valve
10
is higher than the other side of the main valve
10
. Then, a main spool
17
of the main valve
10
is moved to the left and a supply port P of the main valve
10
is connected to a load port A thereof. A load port B of the main valve
10
is connected to a drain port R thereof. Thus, in the air conditioning system, coolant exhausted from an outlet of a compressor
1
is transferred to an outdoor heat exchanger
2
through the ports P and A of the main valve
10
so that the outdoor heat exchanger
2
works as a condenser. The coolant depressurized by an expansion mechanism
3
is transferred to the indoor heat exchanger
4
so that the indoor heat exchanger
4
works as an evaporator. The coolant is transferred from the indoor heat exchanger
4
to an inlet of the compressor
1
through the port B and R of the main valve
10
, thus a cooling cycle is carried out.
Next, when a heating operation is selected, the pilot spool
25
is moved to a converting position by the solenoid coil
27
, as shown in FIG.
2
B. Here, pilot pressure in a chamber
16
at the other side of the main valve
10
is higher than the chamber
15
. Then, the main spool
17
of the main valve
10
is moved to the right and the supply port P is connected to the load port B. The load port A at the other side of the load is connected to the drain port R. Thus, in the air conditioning system, the coolant exhausted from the outlet of the compressor
1
is transferred to the indoor heat exchanger
4
through the ports P and B of the main valve
10
so that the indoor heat exchanger
4
works as a condenser. The coolant depressurized by the expansion mechanism
3
is transferred to the outdoor heat exchanger
2
so that the outdoor heat exchanger
2
works as an evaporator. The coolant is transferred from the outdoor heat exchanger
2
to the inlet of the compressor
1
through the port A and R of the main valve
10
, thus a heating cycle is carried out.
In the meantime, Korean Registration Utility Model Publication Nos. 0127597, 0130152, and 20-0213450 and Korean Patent Publication No. 2001-0007231 disclose various types of main valve operating means in which a slide type spool of the main valve is directly converted by using a thermodynamic piston mechanism, instead of the above-descried pilot valve, or a rotary spool driven by an electric motor is provided at the main valve.
However, the thermodynamic piston mechanism or electric motor for directly driving the main spool is hardly used because converting time is slow and converting operation is inaccurate, and thus the use of such devices results in malfunctions in the operating system.
As a valve used in a hydraulic or pneumatic circuit, a solenoid operated type valve such as the above-described pilot valve is widely used due to its merits of easy control of automatic operation or remote operation and fast and accurate converting time. However, since the solenoid operated type valve utilizes electrical thrust of a solenoid, it is not appropriate for a case of controlling a huge amount of fluid and is usually used for conversion at a pressure of 210 kg/cm
2
and the maximum fluid amount of 80 l/min. Accordingly, the conventional four-way reversing valve as described above is generally configured such that the main valve is a hydraulic operating type and the pilot valve operating the main valve is a solenoid operated type.
To manufacture a four-way reversing valve formed by combining the main valve and the pilot valve, capillary pipes whose diameters are small are further provided, in addition to the coolant connection pipes welded at the main valve. Thus, the number of welding points increases so that manufacturing of a four-way reversing valve becomes complicated and breakdown during manufacture and use thereof is frequent due to welding defects.
SUMMARY OF THE INVENTION
To solve the above-described problems, it is an object of the present invention to a four-way reversing valve which is a solenoid operated type exhibiting an easy control and fast and accurate converting time, in which pilot pressure is converted and a vane type main spool is rotated by using the converted pilot pressure, so that the number of welding points are minimized.
To achieve the above object, there is provided a four-way reversing valve which comprises a valve casing having a plurality of ports through which fluid flows, a valve main body fixedly installed to the valve casing and having a valve chamber in which a plurality of main port connection holes for selectively connecting the ports are formed, a main spool rotatably i
Aser Tech Co., Ltd.
Fox John
Volpe and Koenig P.C.
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