Patent Application
20110162746
The invention relates to an oil balance device and a compressor unit, which are used in multi-air conditioners, water-cooled or air-cooled duct type air conditioners, a scroll-type water-cooled or air-cooled chiller or heat pump, water-cooled package unit and other types of refrigeration units, and a method for performing an oil balance operation between the compressor units.
Generally, variable volume refrigeration units, in which a plurality of outdoor units are connected in parallel, comprises a plurality of oil balance devices connected in parallel to the compressor units.
CN Pat. No. 1707201A discloses a method for performing an oil balance operation by utilizing the compressor discharge pressure to provide the power. The lubricating oil runs subsequently to different compressors belonging to different units but the flow of lubricating oil depends on the start and stop operations of other compressors to provide a pressure difference. The cycling on and off disadvantageeously influences the normal cooling and heating operation of the refrigeration units and increases the start and stop cycling of the compressors to shorten their service life. Furthermore, the balancing of the lubricating oil is driven by the power provided by the other running compressors and the balancing will have problems if one of the other compressors fails, especially when installation height gaps exist between the units.
Furthermore, in other oil balancing schemes, a complex system of pipes is required to be installed inside and outside the outdoor units and the inclination angle of the pipes are strictly limited. These restrictions lead to a high cost for the installation and the manufacture of such devices.
An object of the present invention is to provide an oil balance device and a compressor unit using the oil balance device and a method for performing the oil balance operation between the compressor units to realize a reliable oil supply to each compressor unit and the compressor or compressors therein.
To realize the invention, the present invention provides an oil balance device comprising an oil reservoir, a first pipe, a second pipe, a third pipe and a fourth pipe. The four pipes communicate with the oil reservoir respectively. Each pipe is provided with at least one valve to control the opening and the closing of the corresponding pipe.
The present invention also provides a compressor unit comprising at least a compressor and at least an oil balance device. The oil balance device comprises:
Preferably, the end communicating with the bottom of the oil reservoir of the fourth pipe inserts into the interior of the oil reservoir for a certain height to make sure enough oil would be retained in the compressor unit for its own use when the unit supplies oil to other units.
Preferably, the second valve comprises a valve plate and a magnet below the valve plate and an aperture formed on the valve plate. The size of the aperture makes no difference to the closing of the second valve and pressure difference between the two sides of the valve plates is removed when the second valve is switched from the off status to the on status.
The present invention provides a method for performing an oil balance operation between a plurality of compressor units. The method comprises the following steps:
providing an oil reservoir for each compressor unit;
providing a first pipe, a second pipe, a third pipe and a fourth pipe for each compressor unit;
connecting the first pipe to the oil reservoir of one compressor unit and to the discharge pipe of the compressor;
connecting the second pipe to the oil reservoir of the compressor unit and to the gas balance opening of the compressor;
connecting the third pipe to the oil reservoir of the compressor unit and to the oil balance opening of the compressor;
connecting the fourth pipe to the oil reservoir of the compressor unit and to another oil reservoir belonging to an adjacent compressor unit;
controlling the flow on/flow off status of the first pipe, the second pipe, the third pipe and the fourth pipe by the first valve, the second valve, the third valve and the fourth valve respectively;
closing the first valve and the fourth valve and opening the second valve and the third valve for the plurality of compressor units in normal operation;
opening the first valve and the fourth valve and closing the second valve and the third valve for the compressor units supplying oil;
opening the second valve and the fourth valve and closing the first valve and the third valve, or opening the third valve and the fourth valve and closing the first valve and the second valve, for the compressor units receiving oil.
According to the present invention, excess oil is discharged to an adjacent unit and simultaneously sufficient oil is retained for the use of the supplying unit. Therefore, the oil balance can be achieved without the use of special oil level detecting instruments if the oil cycling between the different oil reservoirs is carried out regularly. In addition, oil cycling between the different units is driven by the discharge pressure of the compressors so that a certain amount of installation height differences is permitted between units.
This invention does not require forcibly controlling the compressors to start and stop, and will not adversely affect the normal operation of the air conditioner; decreases the loss of compressors; and does not need to consider the height difference between the different units when installing.
The present invention will be described further with details, based on the combination of the preferred embodiment of the invention and the accompanying drawings, wherein:
An air conditioning system according to the present invention comprises a plurality of parallel connected compressor units. Each compressor unit comprises one or more parallel connected compressors. The oil balance between the different compressor units is achieved by oil balance devices and corresponding oil balance operations.
The one or more compressor units could be disposed in one or more refrigerating apparatuses, for example, multi-air conditioners, water-cooled or air-cooled duct type air conditioners, scroll-type water-cooled or air-cooled chillers or heat pumps, water-cooled package units and so on. Of course, the application of the present invention should not be limited in the units described above.
A multi-air conditioner system may be taken as an example of the present invention. Each outdoor unit includes a compressor unit and the outdoor units are connected by some gas pipes, liquid pipes, and oil balance pipes. Furthermore, the outdoor units are connected to a plurality of indoor units by some gas pipes and liquid pipes to form an air conditioning system.
In this system each compressor unit comprises one or more than one parallel-connected compressor. The suction pipes and the discharge pipes of the compressors are connected in parallel by some parallel-connected pipes. The parallel-connected compressors are interconnected by an oil balance pipe and a gas balance pipe.
Each compressor unit comprises an oil reservoir and the oil reservoir constitutes an oil balance device with corresponding pipes and control valves. The oil balance device is connected to the compressors in parallel to achieve not only the oil balance between the compressors and the oil reservoir, but also the balance between the oil reservoirs belonging to different compressor units.
The oil balance device according to the prevent invention comprises one oil reservoir and the oil reservoir is connected to the discharge pipe of the compressors through a first connecting pipe and a first control valve. The objective of the connection is that the discharge pressure of the compressors can be used as a power source to force excess oil in the oil reservoir into other units.
The oil reservoir is connected to the gas balance pipe disposed between the compressors through a second connecting pipe and a second control valve. In addition, the oil reservoir is connected to the oil balance pipe through a third connecting pipe and a third control valve. The objective of these connections is that interconnections are created between the oil cavity of the compressors and the oil reservoir. Therefore, the oil level in the compressors and the oil level in the oil reservoir will keep balancing. In other words, the oil quantity in the oil reservoir reflects the oil quantity in the compressors. In normal operation, the oil will automatically flow into the oil reservoir when the oil in the compressors is excessive and the oil will automatically be supplied to the compressors from the oil reservoir when the oil in the compressors is deficient.
The oil reservoir is connected to other oil reservoirs belonging to other units through a fourth connecting pipe and a fourth control valve. The opening and closing of the oil balance pipe between the units can be achieved by the opening and closing of the fourth control valve to control the oil balance between the units.
The first connecting pipe and the second connecting pipe also can be first combined and then connected to the oil reservoir.
The fourth connecting pipe may be inserted into the oil reservoir to a suitable protruding height. The protruding height depends on the size of the oil reservoir and the size of the compressors connecting to the oil reservoir. The objective of setting the protruding height is that enough oil will be retained in the oil reservoir when the oil in the oil reservoir is partially transferred into another unit. The oil will be added to the compressors when the oil level in the compressors is too low such that the reliability of the compressors is improved.
The oil balance between the conditioner units is achieved by the controlling of related valves in the following manner.
Firstly, the oil balance between the compressors belonging to one compressor unit and the balance between the compressors and the oil reservoir in that unit will be performed. Due to the principle of connected vessels, in the interior of each unit the oil level of all the compressors and the oil level of the oil reservoir will balance continuously. The oil will flow into the oil reservoir through the connecting pipe if the oil level in the compressors is too high and the oil in the oil reservoir will automatically supply excess oil to the compressors if the oil level in the compressors is too low. But the oil in the compressors will not flow out through an oil balance aperture once the oil level in the compressors is lower than the oil balance aperture. The height of the bottom of the oil reservoir is the same as that of an oil balance opening of the compressors, or the former is slightly higher, to ensure that the excess oil in the compressor will flow into the oil reservoir.
The oil balance between the compressor units is driven by the power provided by the discharge pressure of the unit supplying the oil. Because the oil reservoir of the compressor unit receiving the oil is in communication with the gas balance pipe of the compressors, the excess oil (the oil above the protruding height) will flow from the unit supplying the oil into the oil reservoir of the unit receiving the oil when the pressure in the oil reservoir of the compressor unit supplying the oil is increased. Each compressor unit will supply oil and the receive oil one by one in a certain order to carry out the oil cycling in such a way that the oil balance between the oil reservoirs belonging to the different compressor units is achieved. In addition, the valve connecting the oil reservoir and the oil balance pipe of the compressors and the valve connecting the oil reservoir and the gas balance pipe of the compressors can be opened to achieve the oil balance between the oil reservoir and the compressors.
The present invention will be described further with details as follows.
With reference to
The indoor unit 15 includes an indoor heat exchanger 15a and an expansion valve 15b. The indoor unit 16 includes an indoor heat exchanger 16a and an expansion valve 16b. Each indoor unit 15, 16 is connected to the liquid pipes and the gas pipes disposed between the indoor units 15, 16 and the outdoor units 1a, 1b.
Because each compressor unit has the same structure, in the following the compressor unit 1a is described as an example. The reference number of each component of the compressor unit 1a corresponds with that of the compressor unit 1b, and the suffixes correspond with compressor units a and b respectively.
As shown in
The inlet of the gas-liquid separator 13a is connected to the four-way valve 10a and the outlet is connected to the suction pipe 21a. The refrigerant is divided in the suction pipe 21a and is drawn into the compressors 2a, 3a respectively.
The top of an oil reservoir 4a is connected to the compressor discharge pipe 26a through a first valve 5a so that the high pressure gas in the compressor can be introduced into the oil reservoir 4a to provide a pressure for the balancing of the lubricating oil in different units. A gas balance pipe 27a is disposed between the paralleled connected compressors 2a,3a and the top of the oil reservoir 4a is connected to the gas balance pipe 27a through a second valve 6a so that the balance of gas pressure between the oil reservoir 4a and the compressors 2a, 3a can be maintained.
An oil balance pipe 22a is disposed between the compressors 2a, 3a. The oil reservoir 4a is connected to the oil balance pipe 22a through another oil balance pipe 23a and a third valve 7a. The connections between the gas balance pipe 24a, the oil balance pipe 23a and the compressors 2a, 3a can achieve not only the oil balance between the parallel connected compressors 2a, 3a, but also the oil balance between the compressors 2a, 3a and the oil reservoir 4a. Furthermore, based on the principle of connected vessels, the oil level in the oil reservoir 4a and the oil level in the compressors 2a, 3a will equalize. When the oil level in the compressors 2a, 3a is too high, the oil will flow into the oil reservoir 4a through the oil balance pipe 23a. When the oil level in the compressors 2a, 3a is too low, the oil in the oil reservoir 4a will automatically be supplied to the compressors 2a, 3a. But when the oil level in the compressors 2a, 3a is lower than an oil balance aperture (safe oil level), the oil in the compressors will not flow out through the oil balance aperture. In summary, the excess oil in the compressors will flow into the oil reservoir 4a due to the principle of connected vessels. Conversely, the oil in the oil reservoir 4a will automatically supply oil to the compressors when the oil level in the compressors is too low.
The oil balance pipe 20 is connected to other units through a fourth valve 8a to provide a lubricating oil connection between the different units 1a, 1b.
A section of pipe disposed between the bottom of the oil reservoir 4a and the fourth valve 8a protrudes into the oil reservoir 4a to a suitable protruding height. The protruding height depends on the size of the oil reservoir 4a and the size of the compressors. The objective of setting the protruding height is that enough oil remain in the compressors 2a, 3a to prevent the oil level in the compressors 2a, 3a of unit 1a from being too low when the oil in the oil reservoir 4a is forced into another unit 1b. The setting the protruding height improves the operational reliability of the compressors.
For illustration,
First Method to Achieve the Oil Balance.
When the oil balance is operated, all the valves in the units should be operated as shown in table 1:
It must be noted that at least one of the compressor units involved in the oil balance operation between the compressor units is operating and all the compressors that are operating are normally regulated by a controller. The Regulation of the compressors by the controller has no influence on the oil balance operation between the units, and vice versa.
In a normal operation, the second valve 6a and the third valve 7a are opened, while the first valve 5a and the fourth valve 8a are closed. The pressure balance between the oil reservoir 4a and the compressors 2a, 3a can be achieved by the connection of the gas balance pipe 24a and the gas balance pipe 27a of the compressors 2a, 3a. Due to the principle of connected vessels, the connection of the oil balance pipe 23a and the oil balance pipe 22a of the compressors 2a, 3a can achieve not only the balance between the two compressors 2a, 3a, but also the balance between the compressors and the oil reservoir 4a. When the oil level in the compressors 2a, 3a is too high, the oil in the compressors will flow into the oil reservoir 4a through the oil balance pipe 23a. When the oil level in the compressors 2a, 3a is too low, the oil in the oil reservoir 4a will automatically be supplied to the compressors. Furthermore, the oil in the compressors will not flow into the oil reservoir 4a through the oil balance opening of the compressors once the oil level in the compressors 2a, 3a is lower than the oil balance opening (safe oil level).
As shown in
The oil reservoir according to the present invention is designed specially and the section of pipe disposed between the bottom of the oil reservoir 4a and the fourth valve 8a is inserted into the oil reservoir 4a to the protruding height. During the first operation, when the oil level in the oil reservoir 4a is higher than the protruding height, it could be considered that the oil level in the unit 1a is higher than a design value. Due to the effect of the compressor discharge pressure, the excess oil will be transferred to the oil reservoir 4b of the other unit 1b. When the oil level in the oil reservoir 4a is lower than the protruding height, it could be considered that the oil level in the unit 1a is lower than the design valve and no oil flows into other units. Because the oil in both compressor units is sufficient to satisfy the lubrication requirement of both units, the oil reservoir 4b of the unit 1b will not be short of oil even at the end of the first operation. The unit 1a will be waiting for a second operation in which other compressor units will supply oil to unit 1a.
Referring to
If the system includes more units, e.g., 1c, 1d (not shown), the oil supply from the unit 1b to the units lc will be processed once the oil supply from the unit 1a to unit 1b is finished. Next the supply from the unit 1c to unit 1d will be processed once the supply from the unit 1b to unit 1c is finished. Similarly, the oil supply operation will be processed one by one until the oil reaches the last unit. Next the oil will flow back from the last unit to other units in reverse order until the oil reaches the first unit. For example, in a system comprising four units, the sequence of the loop is a→b→c→d, and next is d→c→b→a in reverse order. The above sequence is not unique and the main feature is that the lubricating oil in the system will pass through each unit in the forward and reverse order to leave a certain volume of oil in each oil reservoir of each unit to ensure the oil balance in the system.
When the balance operation is done between the units 1a and 1b, the units are then in normal operation. The second valve 6a, 6b and the third valve 7a, 7b are all opened. The first valve 5a, 5b and the fourth valve 8a, 8b are all closed. The opened and closed valves cause the oil level to balance between the oil reservoir and the compressors. The oil flows into the oil reservoir from the compressors when the oil in the compressors is excessive. And the oil reservoir provides surplus oil to the compressor units when the oil in the compressors is too little.
Second Method to Achieve the Oil Balance.
When the oil balance is sought, all the valves in the units should be operated as shown in table 2:
During normal operation, the second valve 6a and the third valve 7a are open and the first valve 5a and the fourth valve 8a are closed. The pressure balance between the oil reservoir and the compressors is achieved by the connection of the gas balance pipe 24a and the gas balance pipe of the compressors. Based on the principle of connected vessels, the connection of the oil balance pipe 23a and the oil balance pipe 22a of the compressors can achieve not only the balance between the compressors 2a, 3a, but also the balance between the compressors and the oil reservoir 4a. The oil in the compressors will flow into the oil reservoir 4a through the oil balance pipe 23a if the oil level in the compressors 2a, 3a is too high. The oil in the oil reservoir 4a will automatically provide oil to the compressors if the oil level in the compressors 2a, 3a is too low. Furthermore, the oil in the compressors will not flow into the oil reservoir through the compressor oil balance openings if the oil level in the compressors 2a, 3a is lower than the oil balance aperture (safe oil level).
In a first operation, the unit 1a supplies oil to other units firstly. The first valve 5a is open to apply the discharge pressure of the compressors onto the oil reservoir 4a. Simultaneously, the second valve 6a and the third valve 7a are closed to prevent not only a gas flow short-circuit, but also to prevent the oil from flowing back into the compressors 2a,3a through the third valve 7a. In such a way, the excess oil (the oil above the protruding height) in the unit 1a will flow into the unit 1b through the open fourth valve 8a. Meanwhile, the fourth valve 8b and the third valve 7b are open, and the first valve 5b and second valve 6b are closed. The excess oil from the unit 1a will pass through the oil reservoir 4b and flow into the compressors 2b, 3b under the force of the compressor discharge pressure.
After a period of time of normal operation of the unit 1a and unit 1b, the second valve 6a, 6b and the third valve 7a, 7b are opened and the first valve 5a, 5b and the fourth valve 8a, 8b are closed. The opened and closed valves allow the oil balance between the oil reservoir and the compressors.
The second operation is executed after a period of time of normal operation. The unit 1b supplies oil to unit 1a and the first valve 5b is opened to apply the discharge pressure of the compressors onto the oil reservoir 4b. Simultaneously, the second valve 6b and the third valve 7b are closed to prevent not only the gas flow short-circuit, but also the oil flowing back into the compressors 2b, 3b through the third valve 7b. In such a way, the excess oil (the oil above the protruding height) in the unit 1b will flow into the unit 1a through the open fourth valve 8b. Meanwhile, the fourth valve 8a and the third valve 7a are opened and the first valve 5a and the second valve 6a are closed. The excess oil from the unit 1b will pass through the oil reservoir 4a and flow into the compressors 2a, 3a under the force of the discharge pressure.
Because the oil in the combined units is sufficient to satisfy the lubrication of the combined units, the oil reservoir 4b of the unit 1b will not be short of oil even after the first operation. The oil reservoir 4a and the compressors of the unit 1a originally depleted of oil, receive supplemental oil after the second operation. Meanwhile, the oil reservoir 4b of compressor unit 1b retains enough lubricating oil for its use and the excess oil is discharged.
If the system includes more units 1c, 1d, the oil supply from the unit 1b to the units 1c will be processed once the oil supply from the unit 1a to unit 1b is finished. Next the supply from the unit 1c to unit 1d will be processed once the supply from the unit 1b to unit 1c is finished. Similarly, the oil supply operation will be processed one by one until the oil reaches the last unit. Next the oil would flow back from the last unit to other units in a reverse order until the oil reaches the first unit. For an example, in a system comprising four units, the sequence of the loop is a→b→c→d, and next is d→c→b→a in a reverse order. The above sequence is not unique and the main feature is that the lubricating oil in the system will pass through each unit in the forward and reverse order to leave a certain volume of oil in each oil reservoir of each unit to ensure oil balance in the system.
The unit receiving the oil will be in normal operation for a period of time after oil receiving is done to balance the oil levels of the compressors and the oil reservoir. Then another oil balancing operation will be executed.
Referring to
The gas balance pipe 24a and an exhaust connecting pipe 25a of the oil reservoir 4a can be separately connected to the oil reservoir 4a and also could be combined together firstly and then connected to the oil reservoir 4a as shown in
The present invention is not only suitable for multi-air conditioner systems, but is also suitable for chiller (heat pump) systems comprising a plurality of parallel-connected compressors, multi-connected air conditioners; water-cooled or air-cooled duct type air conditioners; scroll-type water-cooled or air-cooled chillers or heat pumps, water-cooled package units and so on. The invention is suitable when the air conditioning systems comprise two or more than two parallel connected compressor units and the units are connected in parallel by the pipes on the high-pressure side and low-pressure side to construct a closed refrigerant loop. Furthermore, the oil lines of the compressor units are connected together by the oil balance device according to the present invention which achieves oil balance between the units.
Referring to
Of course, the discharge pipes of units 1a, 1b can be connected to their respective four-way valves, similar to those illustrated in
Furthermore, for some special applications, for example, when two parallel connected compressors are disposed in one housing, the control valves 8a, 8b of the oil balance pipe 20 as illustrated in
The first, second, third and fourth valves in the oil balance device of the present invention are controlled to provide flow connection and flow disconnection of the pipes. The valves can be electromagnetic valves controlled by controllers, or also can be electronic expansion valves (EEVs) controlled by controllers. The EEVs could be opened to a certain extent or closed to achieve the connection and the disconnection of the pipes, based on the demand of the oil balance operation. An EEV can be used to control the pressure difference by controlling the extent of the opening of the EEV, especially for the first valve. Of course, the first, second, third and fourth valves also could be other electric or mechanical valves having similar features. In addition, the valves could be disposed somewhere along the length of the pipes or disposed at the junction of the pipes. In an exemplary embodiment the valves along the length of the pipes may be disposed in the interior of the pipes.
The valves described above, especially the valves 6a, 6b, could be EEVs and the valves could open in normal operation so that the pressure balance between the oil reservoir and the compressors can be achieved. The valves can be closed during the first operation to establish a high pressure in the oil reservoir to force the oil out and the valves can be opened during the second operation to exhaust the gas in the oil reservoir to achieve the transfer of oil.
The present invention also disclosures a check valve designed specially to achieve an improved function of the valves described above.
Generally, a common check valve known to those skilled in the art consists of a valve plate 55, a magnet 53, an upper valve seat 50, a lower valve seat 51 and a shell made of copper tube. To satisfy the requirement of the check valve that flow is possible in one direction and stopped in reverse direction, the lower end surface of the upper valve seat 50 is a contact surface 56. A step is formed in the middle of the lower valve seat 51 and defines a contact surface 52 and a plurality of guiding slots are formed on the circumference of the lower valve seat 51 as shown in
The difference between the check valve of the present invention and the common check valve is that at least one aperture 54 is formed on the valve plate 55 based on the design parameters and the magnet 53 is embedded in the lower valve seat 51 to ensure the check valve is open when there is no pressure difference or only a slight pressure difference.
In normal operation, the valve 6a is forced to open and the valve plate 55 abuts the contacting surface 52 tightly under the magnetic force of the magnet 53 and the gravity. Due to the guiding slots formed on the valve seat 51, the valve is in the open position to achieve the gas balance between the oil reservoir and the compressors. In the first operation, the unit 1a supplies oil. The valve 5a is open and the high pressure gas flows into the oil reservoir. The valve plate 55 overcomes the magnetic force and the gravitational force and abuts the contacting surface 56 tightly under the pressure difference and thus the valve is closed. The size of the aperture 54 formed on the valve plate 55 depends on the design parameters. When the valve is closed, gas leakage through the aperture 54 will be negligible and the gas leakage would not prevent the valve from closing. The objective of setting the size of the aperture 54 is that high pressure can be relieved when the valve 6a changes from the closed status to the open status. For example, the valve 5a will close after the oil is discharged and the high pressure of the gas in the oil reservoir will be relieved through the aperture 54. Meanwhile, the valve plate 55 of the valve 6a would automatically abut the contacting surface 52 under the magnetic force and gravity and thus the valve 6a is opened. In the second operation, the unit 1a receives oil. The valves 5b, 8b, 8a are all opened. The check valve 6a overcomes the magnetic force and gravity and is closed under a high pressure difference. The aperture 54 formed on the valve plate 55 discharges the gas in the oil reservoir to make sure the oil flows into the oil reservoir smoothly.
According to the present invention, it can be achieved that excess oil is discharged and simultaneously enough oil is retained for the use of the unit. Therefore, the oil balance can be achieved without the use of special oil level measuring instruments, while the oil balancing between the different oil reservoirs is carried out regularly.
The oil balance operation does not require interaction of the compressors to perform on/off operations and each compressor just runs under the normal control of the system. The compressors do not have to repeat on/off operations frequently so that the life of the compressors is not shortened.
Oil balancing between the separate compressor units is driven by the discharge pressure of the compressors so that a certain tolerance differences in installation height among units is permitted and the length of the oil balance pipe is not strictly limited. These advantages make the design more flexible and also requires less time for the oil to balance between the compressors.
The present invention supplies oil to each compressor equally so the operation of the compressor units is more reliable.
The present invention achieves oil balance reliably and effectively under normal operation of the compressor units.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20081161327.1 | Sep 2008 | CN | national |
This application is a continuation of International Application No. PCT/CN2009/001040, entitled “OIL EQUALIZING DEVICE, COMPRESSOR UNIT AND OIL EQUALIZING METHOD,” filed on Sep. 17, 2009, which claims priority from and the benefit of China Patent Application No. 200810161327.1, entitled “OIL EQUALIZING DEVICE, COMPRESSOR UNIT AND OIL EQUALIZING METHOD,” filed Sep. 19, 2008, both of which applications are hereby incorporated by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2009/001040 | Sep 2009 | US |
| Child | 13050116 | US |
