CN215930199U - Heat pump rectification circulating condenser - Google Patents
Heat pump rectification circulating condenser Download PDFInfo
- Publication number
- CN215930199U CN215930199U CN202122050117.9U CN202122050117U CN215930199U CN 215930199 U CN215930199 U CN 215930199U CN 202122050117 U CN202122050117 U CN 202122050117U CN 215930199 U CN215930199 U CN 215930199U
- Authority
- CN
- China
- Prior art keywords
- circulating water
- wall
- pipe
- heat pump
- top cover
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 43
- 238000009434 installation Methods 0.000 claims abstract description 23
- 239000007788 liquid Substances 0.000 claims abstract description 9
- 235000017166 Bambusa arundinacea Nutrition 0.000 claims description 6
- 235000017491 Bambusa tulda Nutrition 0.000 claims description 6
- 241001330002 Bambuseae Species 0.000 claims description 6
- 235000015334 Phyllostachys viridis Nutrition 0.000 claims description 6
- 239000011425 bamboo Substances 0.000 claims description 6
- 125000004122 cyclic group Chemical group 0.000 claims description 6
- 230000000694 effects Effects 0.000 claims description 4
- 238000000034 method Methods 0.000 abstract description 2
- 239000002826 coolant Substances 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Images
Landscapes
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
The utility model relates to a circulating condenser for heat pump rectification, which aims to solve the technical problem that the prior device can not be opened to process the inside, and comprises an installation cylinder, wherein the bottom end of the installation cylinder is provided with a liquid outlet pipe, a top cover is arranged at the top end of the mounting cylinder, a fixed structure is arranged on the outer wall of the top cover and the mounting cylinder, a circulating water inlet is arranged at one end of one side of the top cover, and the other end of one side of the top cover is provided with a circulating water outlet, one ends of the circulating water inlet and the circulating water outlet extend to the inside of the top cover, and one end of the circulating water inlet and one end of the circulating water outlet are both provided with an annular pipe, the bottom ends of the annular pipes extend to the inside of the mounting cylinder, and the bottom end of the annular pipe is provided with a communicating pipe, and the circulating water inlet, the annular pipe, the circulating water outlet and one end of the communicating pipe are provided with a connecting structure.
Description
Technical Field
The utility model relates to the technical field of heat pump rectification, in particular to a circulating condenser for heat pump rectification.
Background
The heat pump rectification is a separation method which basically does not provide extra heat for a reboiler except a start-up stage, and is widely applied to the fields of petrochemical industry and the like. The tower top vapor is heated after being adiabatically compressed by a compressor and is used as a heat source of a reboiler again, so that part of liquid is vaporized, and the compressed gas is condensed into liquid. After passing through the throttle valve, one part of the condensate is taken as the distillate at the top of the tower to be extracted, and the other part of the condensate is returned to the tower to be taken as the reflux liquid, so that the condenser is an important device in a heat pump rectification system.
However, the condensers in the market are generally designed in an integrated welding manner in order to ensure a sealed environment, so that dirt generated on the inner shell wall of the condenser after long-term use is difficult to clean, and the pipelines are not convenient to replace after being damaged, and once equipment fails, the equipment is required to be replaced completely, so that resource waste is caused.
Disclosure of Invention
The utility model aims to overcome the defects of the prior art, adapt to practical needs, and provide a circulating condenser for heat pump rectification to solve the technical problem that the conventional device cannot be opened to process the inside.
In order to realize the purpose of the utility model, the technical scheme adopted by the utility model is as follows: a heat pump rectification circulating condenser is designed, and comprises an installation cylinder, wherein a liquid outlet pipe is installed at the bottom end of the installation cylinder, a top cover is installed at the top end of the installation cylinder, and fixing structures are arranged on the top cover and the outer wall of the installation cylinder;
a circulating water inlet is arranged at one end of one side of the top cover, a circulating water outlet is arranged at the other end of one side of the top cover, one ends of the circulating water inlet and the circulating water outlet extend to the inside of the top cover, annular pipes are arranged at one ends of the circulating water inlet and the circulating water outlet, the bottom ends of the annular pipes extend to the inside of the mounting cylinder, a communicating pipe is arranged at the bottom end of each annular pipe, and a connecting structure is arranged at one end of each of the circulating water inlet, the annular pipes, the circulating water outlet and the communicating pipe;
the top of top cap is provided with the intake pipe, and the bottom of intake pipe runs through to the inside of top cap, the inside intake pipe below of top cap is provided with non return structure.
Preferably, fixed knot constructs including fixed box, the top of a fixed box all installation and installation section of thick bamboo outer wall, the fixed block is all installed through the pivot in the inside top of fixed box, and the bottom of fixed block all extends to the below of fixed box, the inside fixed block outer wall of fixed box all overlaps and is equipped with the thread piece, and one side of thread piece all installs the lead screw, the one end of lead screw all extends to one side of fixed box, the hook is all installed to the bottom of top cap outer wall, and the outer wall of hook all overlaps and is equipped with the lantern ring, the rope is all installed to the bottom of the lantern ring, and the bottom of rope all is connected with the top of lead screw.
Preferably, the cross-sectional shapes of the inside of the fixing box and the screw block are both rectangular, and the inside of the fixing box and the screw block have the same size.
Preferably, the non return structure includes mounting box, reset spring, activity stopper and disappointing mouth, the inside intake pipe outer wall of top cap is located to the mounting box cover, and the end top of mounting box is connected with the inside top of top cap, two reset spring are installed to the inside bottom of mounting box, and reset spring's top installs the activity stopper, a plurality of disappointing mouths have been seted up to the outer wall of mounting box.
Preferably, the bottom end of the movable plug and the top end of the air leakage opening are located in the same plane, and the moving distance of the movable plug is larger than the thickness of the movable plug.
Preferably, connection structure includes gag lever post, spacing hole, movable sleeve, first retainer plate and second retainer plate, first retainer plate is all installed in the outer wall of circulating water entry, circulating water export and communicating pipe one end, and the inside of first retainer plate has seted up a plurality of spacing holes, the second retainer plate is all installed in the both ends of annular pipe outer wall, and a plurality of gag lever posts are all installed to the one end of second retainer plate, the one end of gag lever post all runs through to the one end in spacing hole, the outer wall of annular pipe all overlaps and is equipped with two movable sleeves.
Preferably, the inner wall of the movable sleeve is provided with an internal thread, and the outer wall of the first fixing ring is provided with an internal thread matched with the internal thread.
The utility model has the beneficial effects that:
1. the fixing structure is provided, the fixing block is rotated, so that the thread block is driven to directionally move in the fixing box, the screw rod moves upwards, the rope is not in a tight state any more, the lantern ring can be taken down from the hook, the position of the hook is not limited any more, the top cover is screwed down from the mounting cylinder, the device can be rapidly mounted and dismounted under the condition of ensuring the sealing property, the inner wall of the mounting cylinder is convenient to clean, and the problem that the device is inconvenient to open is solved.
2. The utility model provides a non-return structure, after gas leaves an air inlet pipe, the gas pushes a movable plug to overcome a return spring to move, so that the gas can leave an installation box from an air leakage opening without blocking the air leakage opening, enters a top cover and the inside of an installation barrel to start heat exchange, and when the gas pressure is not enough, the return spring resets the movable plug to block an outlet of the air inlet pipe, so that the phenomenon of backflow caused by the fact that the gas leaves the air inlet pipe is avoided, and the problem of gas backflow is solved.
3. The utility model provides a connecting structure, after a top cover and an installation cylinder are separated, a ring-shaped pipe and a communicating pipe are connected with the top cover and taken down together, a movable sleeve is rotated to be separated from a first fixing ring, then the ring-shaped pipe is pulled to separate the first fixing ring from a second fixing ring, a limiting rod is separated from the inside of a limiting hole, relative sliding between the first fixing ring and the second fixing ring is not limited, the ring-shaped pipe and the communicating pipe can be detached respectively, and the pipeline to be replaced can be replaced quickly according to the requirement, so that the problem that the pipeline is inconvenient to replace is solved.
Drawings
FIG. 1 is a schematic front sectional view of the present invention;
FIG. 2 is a schematic top view of the present invention;
FIG. 3 is a schematic side view of the connecting structure of the present invention;
FIG. 4 is an enlarged schematic view of the structure at A in FIG. 1 according to the present invention;
fig. 5 is an enlarged schematic view of the structure at B in fig. 1 according to the present invention.
In the figure: 1. a non-return structure; 101. mounting a box; 102. a return spring; 103. a movable plug; 104. an air escape opening; 2. a connecting structure; 201. a limiting rod; 202. a limiting hole; 203. a movable sleeve; 204. a first retainer ring; 205. a second retainer ring; 3. a top cover; 4. a circulating water inlet; 5. a collar; 6. mounting the cylinder; 7. an annular tube; 8. a liquid outlet pipe; 9. an air inlet pipe; 10. a circulating water outlet; 11. a hook; 12. a fixing box; 13. a thread block; 14. a communicating pipe; 15. a screw rod; 16. a fixed block; 17. a rope.
Detailed Description
The utility model is further illustrated with reference to the following figures and examples:
example 1: referring to fig. 1-5, a heat pump rectification cyclic condenser comprises an installation cylinder 6, a liquid outlet pipe 8 is installed at the bottom end of the installation cylinder 6, a top cover 3 is installed at the top end of the installation cylinder 6, and fixing structures are arranged on the top cover 3 and the outer wall of the installation cylinder 6;
a circulating water inlet 4 is arranged at one end of one side of the top cover 3, a circulating water outlet 10 is arranged at the other end of one side of the top cover 3, one ends of the circulating water inlet 4 and the circulating water outlet 10 extend to the inside of the top cover 3, an annular pipe 7 is arranged at one ends of the circulating water inlet 4 and the circulating water outlet 10, the bottom end of the annular pipe 7 extends to the inside of the mounting cylinder 6, a communicating pipe 14 is arranged at the bottom end of the annular pipe 7, and a connecting structure 2 is arranged at one end of the circulating water inlet 4, the annular pipe 7, the circulating water outlet 10 and the communicating pipe 14;
an air inlet pipe 9 is arranged at the top end of the top cover 3, the bottom end of the air inlet pipe 9 penetrates into the top cover 3, and a check structure 1 is arranged below the air inlet pipe 9 in the top cover 3;
referring to fig. 1-5, a heat pump rectification cyclic condenser further comprises a fixing structure, the fixing structure comprises a fixing box 12, the fixing box 12 is installed on the top end of the outer wall of the installation cylinder 6, a fixing block 16 is installed on the top end inside the fixing box 12 through a rotating shaft, the bottom end of the fixing block 16 extends to the lower portion of the fixing box 12, the outer wall of the fixing block 16 inside the fixing box 12 is sleeved with a threaded block 13, a lead screw 15 is installed on one side of the threaded block 13, one end of the lead screw 15 extends to one side of the fixing box 12, a hook 11 is installed at the bottom end of the outer wall of the top cover 3, a lantern ring 5 is sleeved on the outer wall of the hook 11, a rope 17 is installed at the bottom end of the lantern ring 5, and the bottom end of the rope 17 is connected with the top end of the lead screw 15;
the cross-sectional shapes of the inside of the fixed box 12 and the thread block 13 are both rectangular, and the inside of the fixed box 12 and the thread block 13 have the same size;
specifically, as shown in fig. 1, fig. 2 and fig. 5, rotatory fixed block 16 to drive screw block 13 and remove at the inside orientation of fixed box 12, make lead screw 15 follow and shift up, make rope 17 no longer be in the tight state, can take off the lantern ring 5 from hook 11, no longer restrict the position of hook 11, spin down the top cap 3 from installation section of thick bamboo 6 again, can install the dismantlement to the device fast under the condition of guaranteeing the leakproofness, conveniently clear up the inner wall of installation section of thick bamboo 6.
Example 2: the check structure 1 comprises a mounting box 101, a return spring 102, a movable plug 103 and air leakage openings 104, wherein the mounting box 101 is sleeved on the outer wall of the air inlet pipe 9 inside the top cover 3, the top end of the bottom of the mounting box 101 is connected with the top end inside the top cover 3, two return springs 102 are mounted at the bottom end inside the mounting box 101, the movable plug 103 is mounted at the top end of each return spring 102, and the outer wall of the mounting box 101 is provided with a plurality of air leakage openings 104;
the bottom end of the movable plug 103 and the top end of the air release opening 104 are positioned in the same plane, and the moving distance of the movable plug 103 is greater than the thickness of the movable plug 103;
specifically, as shown in fig. 1, after the gas leaves the gas inlet pipe 9, the movable plug 103 is pushed to move to overcome the reset spring 102, so that the gas does not block the gas release opening 104, the gas can leave the mounting box 101 from the gas release opening 104, the gas enters the top cover 3 and the mounting barrel 6 to start heat exchange, when the gas pressure is not enough, the reset spring 102 resets the movable plug 103 to block the outlet of the gas inlet pipe 9, and the gas is prevented from leaving from the gas inlet pipe 9 and flowing back.
Example 3: the connecting structure 2 comprises limiting rods 201, limiting holes 202, movable sleeves 203, a first fixing ring 204 and a second fixing ring 205, the first fixing ring 204 is installed on the outer wall of the circulating water inlet 4, the circulating water outlet 10 and one end of the communicating pipe 14, a plurality of limiting holes 202 are formed in the first fixing ring 204, the second fixing ring 205 is installed at two ends of the outer wall of the annular pipe 7, a plurality of limiting rods 201 are installed at one end of the second fixing ring 205, one end of each limiting rod 201 penetrates through one end of each limiting hole 202, and two movable sleeves 203 are sleeved on the outer wall of the annular pipe 7;
the inner wall of the movable sleeve 203 is provided with internal threads, and the outer wall of the first fixing ring 204 is provided with internal threads matched with the internal threads;
specifically, as shown in fig. 1, 3 and 4, after the top cover 3 and the mounting tube 6 are separated, the annular tube 7 and the communicating tube 14 are communicated with the top cover 3 and taken down together, the movable sleeve 203 is rotated again to be separated from the first fixing ring 204, and then the annular tube 7 is pulled, so that the first fixing ring 204 is separated from the second fixing ring 205, the limiting rod 201 is separated from the inside of the limiting hole 202, relative sliding between the first fixing ring 204 and the second fixing ring 205 is not limited, the annular tube 7 and the communicating tube 14 can be detached respectively, and the replaced pipeline can be replaced rapidly as required, which is very convenient.
The working principle is as follows: when the device is used, the device is firstly installed at a proper position in a heat pump rectification system, so that gas is introduced from the gas inlet pipe 9, meanwhile, a cooling medium is introduced from the circulating water inlet 4, the cooling medium can enter the annular pipe 7 from the circulating water inlet 4, passes through the communicating pipe 14 and then enters the circulating water outlet 10 from the annular pipe 7 at the other side to leave, circulation is generated, the media extend the path in the installation cylinder 6 through the annular pipe 7 and perform sufficient heat exchange with the gas to be cooled, and the gas is condensed and can be discharged from the liquid outlet pipe 8;
after the gas leaves the gas inlet pipe 9, the movable plug 103 is pushed to overcome the reset spring 102 to move, so that the gas does not shield the gas release opening 104, the gas can leave the mounting box 101 from the gas release opening 104 and enter the top cover 3 and the mounting cylinder 6 to start heat exchange, when the gas pressure is insufficient, the reset spring 102 resets the movable plug 103 to shield the outlet of the gas inlet pipe 9, and the phenomenon that the gas leaves from the gas inlet pipe 9 and flows back is avoided;
after the device is used for a long time, the inner wall of the mounting cylinder 6 is easy to generate certain dirt, if the device is not cleaned in time, the heat exchange efficiency is possibly damaged, at the moment, the fixing block 16 can be rotated, so that the thread block 13 is driven to directionally move in the fixing box 12, the lead screw 15 moves upwards along with the thread block, the rope 17 is not in a tight state any more, the lantern ring 5 can be taken down from the hook 11, the position of the hook 11 is not limited any more, the top cover 3 is screwed down from the mounting cylinder 6, the device can be rapidly mounted and dismounted under the condition of ensuring the sealing property, and the inner wall of the mounting cylinder 6 is convenient to clean;
if annular pipe 7 or communicating pipe 14 take place to damage, can be after separating top cap 3 and installation section of thick bamboo 6, take off annular pipe 7 and communicating pipe 14 intercommunication top cap 3 together, rotatory movable sleeve 203 again, make it separate with first retainer plate 204, pulling annular pipe 7 afterwards, make first retainer plate 204 and second retainer plate 205 part, gag lever post 201 breaks away from spacing hole 202 is inside, no longer restrict the relative slip between first retainer plate 204 and the second retainer plate 205, can pull down annular pipe 7 and communicating pipe 14 respectively, change the pipeline of changing fast as required, and is very convenient.
The embodiments of the present invention are disclosed as the preferred embodiments, but not limited thereto, and those skilled in the art can easily understand the spirit of the present invention and make various extensions and changes without departing from the spirit of the present invention.
Claims (7)
1. The utility model provides a circulating condenser of heat pump rectification, includes the installation section of thick bamboo, its characterized in that: the liquid outlet pipe is mounted at the bottom end of the mounting cylinder, the top cover is mounted at the top end of the mounting cylinder, and the top cover and the outer wall of the mounting cylinder are provided with fixing structures;
a circulating water inlet is arranged at one end of one side of the top cover, a circulating water outlet is arranged at the other end of one side of the top cover, one ends of the circulating water inlet and the circulating water outlet extend to the inside of the top cover, annular pipes are arranged at one ends of the circulating water inlet and the circulating water outlet, the bottom ends of the annular pipes extend to the inside of the mounting cylinder, a communicating pipe is arranged at the bottom end of each annular pipe, and a connecting structure is arranged at one end of each of the circulating water inlet, the annular pipes, the circulating water outlet and the communicating pipe;
the top of top cap is provided with the intake pipe, and the bottom of intake pipe runs through to the inside of top cap, the inside intake pipe below of top cap is provided with non return structure.
2. The heat pump rectification cyclic condenser of claim 1, wherein: the fixed knot constructs including fixed box, the top of fixed box all installation and installation section of thick bamboo outer wall, the fixed block is all installed through the pivot on the inside top of fixed box, and the bottom of fixed block all extends to the below of fixed box, the inside fixed block outer wall of fixed box all overlaps and is equipped with the screw thread piece, and one side of screw thread piece all installs the lead screw, the one end of lead screw all extends to one side of fixed box, the hook is all installed to the bottom of top cap outer wall, and the outer wall of hook all overlaps and is equipped with the lantern ring, the rope is all installed to the bottom of the lantern ring, and the bottom of rope all is connected with the top of lead screw.
3. The heat pump rectification cycle condenser of claim 2, wherein: the cross-sectional shapes of the inside of the fixed box and the thread block are both rectangular, and the inside of the fixed box and the thread block have the same size.
4. The heat pump rectification cyclic condenser of claim 1, wherein: the non return structure includes mounting box, reset spring, activity stopper and disappointing mouth, the inside intake pipe outer wall of top cap is located to the mounting box cover, and the end top of mounting box is connected with the inside top of top cap, two reset spring are installed to the inside bottom of mounting box, and reset spring's top installs the activity stopper, a plurality of disappointing mouths have been seted up to the outer wall of mounting box.
5. The heat pump rectification cyclic condenser of claim 4, wherein: the bottom end of the movable plug and the top end of the air leakage opening are located in the same plane, and the moving distance of the movable plug is larger than the thickness of the movable plug.
6. The heat pump rectification cyclic condenser of claim 1, wherein: connection structure includes gag lever post, spacing hole, movable sleeve, first retainer plate and second retainer plate, first retainer plate is all installed in the outer wall of circulating water entry, circulating water export and communicating pipe one end, and the inside of first retainer plate has seted up a plurality of spacing holes, the second retainer plate is all installed in the both ends of annular pipe outer wall, and a plurality of gag lever posts are all installed to the one end of second retainer plate, the one end of gag lever post all runs through to the one end in spacing hole, the outer wall of annular pipe all overlaps and is equipped with two movable sleeves.
7. The heat pump rectification cycle condenser of claim 6, wherein: the inner wall of the movable sleeve is provided with internal threads, and the outer wall of the first fixing ring is provided with the internal threads matched with the internal threads.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122050117.9U CN215930199U (en) | 2021-08-29 | 2021-08-29 | Heat pump rectification circulating condenser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122050117.9U CN215930199U (en) | 2021-08-29 | 2021-08-29 | Heat pump rectification circulating condenser |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215930199U true CN215930199U (en) | 2022-03-01 |
Family
ID=80421103
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202122050117.9U Active CN215930199U (en) | 2021-08-29 | 2021-08-29 | Heat pump rectification circulating condenser |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215930199U (en) |
-
2021
- 2021-08-29 CN CN202122050117.9U patent/CN215930199U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN215930199U (en) | Heat pump rectification circulating condenser | |
| CN203615793U (en) | Detachable type heat pipe exchanger | |
| CN205825742U (en) | A kind of plural serial stage energy-saving condenser | |
| KR20110128709A (en) | Assembling method of tube and tube sheet of the heat exchanger | |
| CN210645196U (en) | Cylinder body structure and oil mist trap | |
| CN110732226B (en) | Novel super-energy-efficiency vertical type cold drying machine and use method | |
| WO2020207018A1 (en) | Air-cooled motor-dedicated lubricant feeding pipe | |
| CN208959935U (en) | A kind of condenser pipe and the distilling apparatus using the condenser pipe | |
| CN207745540U (en) | A kind of vacuum buffer tank | |
| CN202692762U (en) | Evaporative cooling device with low resistance fall | |
| CN208671718U (en) | Condensate water recovery device | |
| CN213113239U (en) | Filter for natural gas conveying pipeline | |
| CN210934337U (en) | Oil mist trap and clean system | |
| CN205332838U (en) | Vertical heat exchanger | |
| CN208779968U (en) | A kind of condensation module unitized exchanger | |
| CN209386640U (en) | A kind of liquid storage device of compressor of air conditioner anti-tamper | |
| CN211215504U (en) | Condensation subassembly and oil mist trap | |
| CN207145351U (en) | A kind of water-jet pump with condensation function | |
| CN202692766U (en) | Low-resistance heat exchange tube bundle device | |
| CN220649156U (en) | Condensing structure of condenser | |
| CN210567478U (en) | High-efficiency energy-saving heat exchange steam trap | |
| CN107286997B (en) | Associated gas deoiling device | |
| CN110478934A (en) | Condensation and oil mist trapping device | |
| CN205002632U (en) | High -efficient petroleum pipeline heat exchanger | |
| CN215692924U (en) | Epichlorohydrin separation preparation facilities |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address | ||
| CP03 | Change of name, title or address |
Address after: 342500 1st floor, building B, standard plant of state owned assets Corporation, east of Jinlong Avenue, Ruijin economic and Technological Development Zone, Ganzhou City, Jiangxi Province Patentee after: Jiangxi Lvmeirui Ecological Technology Co.,Ltd. Country or region after: China Address before: 342500 1st floor, building B, standard plant of state owned assets Corporation, east of Jinlong Avenue, Ruijin economic and Technological Development Zone, Ganzhou City, Jiangxi Province Patentee before: Jiangxi lumeirui Ecological Construction Co.,Ltd. Country or region before: China |