Monoclonal antibody to human cd44

Abstract

A wastewater treatment device for metribuzin production wastewater relates to the field of wastewater reuse technology. The crystallization vessel is equipped with a stirrer, within which a central refrigerant circulation system is installed. A pipe-wall refrigerant circulation system is installed within the annulus of the inner and outer cylinders. A scraping assembly is installed on the inner wall of the crystallization vessel, its up-and-down movement controlled by a drive assembly, which in turn is driven to rotate by the stirrer. The advantages of this invention are: the pipe-wall refrigerant circulation system and the rotating central refrigerant circulation system within the crystallization vessel result in higher heat exchange efficiency between the refrigerant and the crystallization liquid; the scraping assembly, driven by the drive assembly, scrapes off the crystallized layer from the inner wall of the inner cylinder; and the vibration and striking assembly dislodges crystals from the impeller and stirring shaft, ensuring that the heat exchange surface remains in constant contact with the crystallization liquid for heat exchange. This results in rapid crystallization, uniform crystal particles, and improved crystallization efficiency and quality.

Description

Technical Field

[0001] This invention relates to the field of wastewater reuse technology in metribuzin production, and in particular to a resource-based treatment device for metribuzin production wastewater. Background Technology

[0002] The mainstream preparation method of bentazon uses isopropylamine and methyl anthranilate as starting materials, and triethylamine as an acid-binding agent, through a three-step core reaction of condensation-cyclization-acidification. After the acidification reaction, bentazon crystals precipitate, and the remaining mother liquor is used to recover triethylamine, thus reducing production costs. The remaining process water is passed through a crystallization reactor, stirred and cooled, and then trisodium dodecahydrate is cooled and crystallized, separating it from the process water. Sodium chloride is then obtained through separation processes such as evaporation concentration and cooling crystallization, thus achieving resource utilization of the production wastewater. The cooling crystallization effect and particle uniformity of trisodium dodecahydrate depend on the heat exchange intensity and heat exchange uniformity in the crystallization vessel. The current problem in production is that in the initial stage of cooling crystallization of trisodium dodecahydrate, crystallization first occurs on the heat exchange surface of the refrigerant, forming a crystalline layer similar to frost. This crystalline layer hinders the crystallization rate and particle size of the remaining liquid in the crystallization vessel, resulting in a slow crystallization rate and inconsistent particle size. Uncrystallized trisodium dodecahydrate is also left in the tail liquid. Summary of the Invention

[0003] To address the problem of poor crystallization effect of trisodium dodecahydrate in the current recycling of metribuzin production wastewater, this invention provides a wastewater resource treatment device for metribuzin production.

[0004] The technical solution provided by this invention is: a resource-based treatment device for wastewater from metribuzin production, comprising a crystallization kettle, an agitator on the crystallization kettle, a central refrigerant circulation system inside the agitator, the crystallization kettle being composed of a cover plate, a bottom plate, an inner cylinder, an annular plate, and an outer cylinder, a pipe wall refrigerant circulation system being provided in the annular space between the inner and outer cylinders, a scraping assembly being provided on the inner wall of the crystallization kettle, the scraping assembly being controlled to move up and down by a drive assembly, the drive assembly being driven to rotate by the agitator, the agitator including a geared motor and a stirring paddle, the geared motor and the stirring paddle being connected by a coupling, and a vibration striking assembly being provided at the coupling.

[0005] The inner cylinder, outer cylinder, ring plate and bottom plate are welded into a closed annular jacket. The cover plate is connected to the jacket by sealing ring and bolts. The bottom of the outer cylinder is provided with a refrigerant inlet pipe B and the top of the outer cylinder is provided with a refrigerant outlet pipe B. The jacket, refrigerant inlet pipe B and refrigerant outlet pipe B form a pipe wall refrigerant circulation system. A refrigerant inlet pipe A is welded to the center of the bottom plate. The refrigerant inlet pipe A extends into the crystallizer. The bottom plate is equipped with a discharge pipe, and the cover plate is equipped with a feed pipe. The agitator includes an agitator shaft with several hollow blades on its outer side. An internal flow hole is formed from the bottom up on the agitator shaft. Baffles are installed inside the blades, with their sides connected to the inner walls of the blades. Space is left between the outer sides of the baffles and the inner walls of the blades. The internal flow hole connects the internal spaces of each blade. The lower part of the agitator shaft is rotatably sealed to the refrigerant inlet pipe A via a mechanical seal. The upper part of the agitator shaft is rotatably connected to a cover plate via a mechanical seal. A side hole is formed on the upper part of the agitator shaft, communicating with the internal flow hole. A refrigerant outlet pipe A is fixedly installed on the cover plate. A bypass sleeve is provided on one side of the refrigerant outlet pipe A, located outside the side hole. A slot is formed in the inner hole of the bypass sleeve, communicating with the inner hole of the refrigerant outlet pipe A. Both the upper and lower sides of the bypass sleeve are rotatably connected to the agitator shaft via mechanical seals. A geared motor is connected to the upper part of the agitator shaft via a coupling. The geared motor is fixedly connected to an agitator support, which is fixedly connected to the cover plate. The refrigerant inlet pipe A, refrigerant outlet pipe A, and agitator constitute a central refrigerant circulation system.

[0006] The drive assembly includes a top plate with a raised tube at its center. The raised tube is connected to the stirring shaft via a set screw A. A ring of vertical ribs is welded around the outer circumference of the top plate. A ground ring is welded below the vertical ribs. A raised ring is located below the ground ring. A ring groove is machined on the bottom plate. The raised ring is rotatably connected to the ring groove. A helical rack is welded to the outside of the vertical ribs. The helical rack has a 60° tooth tip structure. The helical rack covers the height of the vertical ribs from top to bottom. The continuous upper and lower helical racks form a male thread structure. The continuous upper and lower helical racks do not contact each other. The scraping assembly includes a nut with a helical toothed groove machined into its inner hole. The helical toothed groove has a 60° tooth tip structure and forms a female thread structure. The pitch and tooth tip size of the helical toothed groove match the helical rack. The outer circle of the nut has an annular groove machined into which a scraping ring is installed. The scraping ring has a helical structure with more than one helical turn. The groove has evenly distributed countersunk holes on its circumference. A compression spring A is installed in the countersunk holes. The outer end of the compression spring A is welded to the inner hole of the scraping ring. The scraping ring is in contact with the inner cylinder, and the compression spring A is in a compressed state.

[0007] The coupling includes a clamping sleeve, a rubber block, and a clamping shaft. The clamping sleeve, rubber block, and clamping shaft form a plum blossom connector. The clamping shaft is fixedly connected to a geared motor, and the clamping sleeve is fixedly connected to a stirring shaft. A protrusion is provided on one side of the clamping sleeve, and the protrusion has a notch in the opposite direction of rotation. An elastic column is fixedly connected to the stirring support, and an impact ball is fixedly connected to the other end of the elastic column. When the protrusion rotates, it can contact and impact the ball. The coupling, elastic column, impact ball, and stirring support form a vibration and impact assembly.

[0008] Helical blade A is welded to the inside of the vertical rib, and helical blade B is welded to the inner wall of the outer cylinder.

[0009] The mechanical seal is a standard 108U type structure, including a stationary ring, a rotating ring, a cage, a compression spring B, a locating sleeve, and a set screw B.

[0010] The geared motor operates alternately in forward and reverse directions, with the forward and reverse rotation times being the same.

[0011] The beneficial effects of this invention are as follows: By setting up a pipe wall refrigerant circulation system and a rotating central refrigerant circulation system inside the crystallization vessel, the heat exchange efficiency between the refrigerant and the crystallization liquid is improved. At the same time, a scraping component is set in the inner cylinder, which moves up and down under the drive of the drive component to scrape off the crystallized layer on the inner wall of the inner cylinder. A vibration and tapping component is set up to shake off the crystals on the impeller and stirring shaft, so that the heat exchange surface always keeps in contact with the crystallization liquid for heat exchange. The crystallization speed is fast, the crystallized particles are uniform, and the crystallization efficiency and crystallization quality are improved. Attached Figure Description

[0012] Appendix Figure 1 This is a schematic diagram of the structure of the present invention; Appendix Figure 2 This is a schematic diagram of the crystallization vessel in this invention; Appendix Figure 3 This is a schematic diagram of the structure of the driving component and the scraping component in this invention; Appendix Figure 4 This is a schematic diagram of the scraping assembly in this invention; Appendix Figure 5 It is attached Figure 3 Enlarged view of point D; Appendix Figure 6 This is a schematic diagram of the structure of the stirring paddle in this invention; Appendix Figure 7 It is attached Figure 1 CC cross-section; Appendix Figure 8 It is attached Figure 1 Enlarged view of point A; Appendix Figure 9 It is attached Figure 1 Enlarged view of point B.

[0013] In the diagram: 1-Crystallization vessel, 101-Cover plate, 102-Bottom plate, 1021-Annular groove, 103-Inner cylinder, 104-Outer cylinder, 105-Annular plate, 2-Drive assembly, 201-Top plate, 202-Ground ring, 203-Vertical rib, 204-Helical rack, 205-Helical blade A, 206-Protruding tube, 207-Protruding ring, 3-Agitator, 301-Agitator shaft, 302-Blade, 303-Baffle plate, 304-Side hole, 305-Inner flow hole, 4-Scraper assembly, 401-Nut, 4011-Groove, 4012-Helical groove, 4013-Counterhole, 402-Scraper ring, 403-Compression spring A, 5-Agitator Support, 6-Coupling, 601-Clamping sleeve, 6011-Protrusion, 6012-Notch, 602-Rubber block, 603-Clamping shaft, 7-Refrigerant outlet pipe A, 701-Bypass sleeve, 702-Empty groove, 8-Refrigerant inlet pipe A, 9-Refrigerant outlet pipe B, 10-Refrigerant inlet pipe B, 11-Feed pipe, 12-Discharge pipe, 13-Gear motor, 14-Impact ball, 15-Elastic column, 16-Mechanical seal, 161-Stationary ring, 162-Dynamic ring, 163-Cage, 164-Compression spring B, 165-Positioning sleeve, 17-Set screw A, 18-Set screw B, 19-Helical blade B, 20-Cladle. Detailed Implementation

[0014] like Figures 1-9 As shown, a wastewater resource utilization treatment device for metribuzin production includes a crystallization tank 1. The crystallization tank 1 is equipped with an agitator and a central refrigerant circulation system. The crystallization tank 1 is composed of a cover plate 101, a bottom plate 102, an inner cylinder 103, an annular plate 105, and an outer cylinder 104. A pipe wall refrigerant circulation system is provided in the annular space between the inner cylinder 103 and the outer cylinder 104. A scraping assembly 4 is provided on the inner wall of the crystallization tank 1. The scraping assembly 4 is controlled to move up and down by a drive assembly 2. The drive assembly 2 is driven to rotate by the agitator. The agitator includes a geared motor 13 and a stirring paddle 3. The geared motor 13 and the stirring paddle 3 are connected by a coupling 6. A vibration impact assembly is provided at the coupling 6.

[0015] The inner cylinder 103, outer cylinder 104, ring plate 105 and bottom plate 102 are welded to form a closed annular jacket 20. The cover plate 101 is connected to the jacket 20 by sealing ring and bolts. The bottom of the outer cylinder 104 is provided with a refrigerant inlet pipe B10 and the upper part of the outer cylinder 104 is provided with a refrigerant outlet pipe B9. The jacket 20, the refrigerant inlet pipe B10 and the refrigerant outlet pipe B9 form a pipe wall refrigerant circulation system. A refrigerant inlet pipe A8 is welded to the center of the base plate 102. The refrigerant inlet pipe A8 extends into the crystallizer 1. The base plate 102 is provided with a discharge pipe 12, and the cover plate 101 is provided with a feed pipe 11. The agitator 3 includes an agitator shaft 301, with several blades 302 on the outer side of the agitator shaft 301. The blades 302 are hollow. The agitator shaft 301 has an internal flow hole 305 opening from the bottom upwards. The blades 302 have a baffle 303 inside, with both sides of the baffle 303 connected to the inner wall of the blades 302. There is a space between the outer side of the baffle 303 and the inner wall of the blades 302. The internal flow hole 305 connects the internal spaces of each blade 302. The lower part of the agitator shaft 301 is rotatably sealed to the refrigerant inlet pipe A8 through a mechanical seal 16. The upper part of the agitator shaft 301 is rotatably connected to the cover plate 101 through the mechanical seal 16. The upper part of the agitator shaft 301 has a side hole 304 opening, which communicates with the internal flow hole 305. The refrigerant outlet pipe A7 is fixedly installed on the cover plate 101. A bypass sleeve 701 is provided on one side of the refrigerant outlet pipe A7. The bypass sleeve 701 is located outside the side hole 304. The inner hole of the bypass sleeve 701 has a slot 702, which is connected to the inner hole of the refrigerant outlet pipe A7. The upper and lower sides of the bypass sleeve 701 are rotatably connected to the stirring shaft 301 through the mechanical seal 16. The upper part of the stirring shaft 301 is connected to the geared motor 13 through the coupling 6. The geared motor 13 is fixedly connected to the stirring support 5. The stirring support 5 is fixedly connected to the cover plate 101. The refrigerant inlet pipe A8, the refrigerant outlet pipe A7 and the stirring blade 3 form a central refrigerant circulation system. The refrigerant flowing in flows upward through the inner flow hole 305 and the inside of each blade 302, and flows out from the outlet refrigerant outlet pipe A7, which plays a heat exchange role while stirring.

[0016] The drive assembly 2 includes a top plate 201, with a raised tube 206 at the center of the top plate 201. The raised tube 206 is connected to the stirring shaft 301 by a set screw A17. A ring of vertical ribs 203 is welded to the outer circle of the top plate 201. A ground ring 202 is welded to the lower part of the vertical ribs 203. A raised ring 207 is provided at the lower part of the ground ring 202. A ring groove 1021 is machined on the bottom plate 102. The raised ring 207 is rotatably connected to the ring groove 1021. A helical rack 204 is welded to the outside of the vertical ribs 203. The cross section of the helical rack 204 is a 60° tooth tip structure. The helical rack 204 covers the height of the vertical ribs 203 from top to bottom. The continuous upper and lower helical racks 204 form a male thread structure. The continuous upper and lower helical racks 204 do not contact each other. This design is so that the drive assembly 2 can drive the scraping assembly 4 to rise and fall at the same time, the unconnected helical racks 204 can not obstruct the flow of the crystallizing liquid. The scraping assembly 4 includes a nut 401, the inner hole of which is machined with a helical toothed groove 4012. The cross-section of the helical toothed groove 4012 is a 60° tooth tip structure. The helical toothed groove 4012 forms a female thread structure. The pitch and tooth tip size of the helical toothed groove 4012 are matched with the helical rack 204. The outer circle of the nut 401 is machined with an annular groove 4011. A scraping ring 402 is installed in the groove 4011. The scraping ring 402 has a helical structure with more than 1 helical turn, so that there is no gap in the circumferential direction when the scraping ring 402 scrapes the inner cylinder 103 from top to bottom. The groove 4011 has circumferentially distributed countersunk holes 4013. A compression spring A403 is installed in the countersunk hole 4013. The outer end of the compression spring A403 is welded to the inner hole of the scraping ring 402. The scraping ring 402 is in contact with the inner cylinder 103, and the compression spring A403 is in a compressed state.

[0017] The coupling 6 includes a clamping sleeve 601, a rubber block 602, and a clamping shaft 603. The clamping sleeve 601, the rubber block 602, and the clamping shaft 603 form a plum blossom connector. The clamping shaft 603 is fixedly connected to the reduction motor 13, and the clamping sleeve 601 is fixedly connected to the stirring shaft 301. A protrusion 6011 is provided on one side of the clamping sleeve 601. The protrusion 6011 has a notch 6012 in the opposite direction of rotation. An elastic column 15 is fixedly connected to the stirring support 5. An impact ball 14 is fixedly connected to the other end of the elastic column 15. When the protrusion 6011 rotates, it can contact and impact the impact ball 14. The coupling 6, the elastic column 15, the impact ball 14, and the stirring support 5 form a vibration and impact assembly.

[0018] The scraping ring 402 transmits torque to the nut 401 through the compression spring A403. The compression spring A403 causes the scraping ring 402 to be elastically locked against the inner wall of the inner cylinder 103, preventing the nut 401 from rotating. The reduction motor 13 rotates forward and reverse alternately, with the forward and reverse rotation times being the same. The reduction motor 13 drives the stirring shaft 301 to rotate, which in turn drives the drive assembly 2 to rotate. Under the rotation of the helical rack 204, the nut 401 drives the scraping ring 402 to move up and down, scraping off the crystallized layer on the inner wall of the inner cylinder 103. At the same time, when the reduction motor 13 rotates, the protrusion 6011 rotates to obstruct the impact ball 14, causing the elastic column 15 to deform. After the protrusion 6011 rotates, the impact ball 14 strikes the clamping sleeve 601 under the rebound of the elastic column 15, causing the stirring shaft 301 to vibrate and shake off the crystals on the blade 302 and the stirring shaft 301.

[0019] A pipe wall refrigerant circulation system and a rotating central refrigerant circulation system are installed inside the crystallizing vessel 1 to improve the heat exchange efficiency between the refrigerant and the crystallizing liquid. At the same time, a scraping component 4 is installed in the inner cylinder 103. The scraping component 4 moves up and down under the drive of the drive component 2 to scrape off the crystallized layer on the inner wall of the inner cylinder 103. A vibration and knocking component is installed to shake off the crystals on the impeller 302 and the stirring shaft 301, so that the heat exchange surface always keeps in contact with the crystallizing liquid for heat exchange. The crystallization speed is fast and the crystal particles are uniform, which improves the crystallization efficiency and crystallization quality.

[0020] The inner side of the vertical rib 203 is welded with a spiral blade A205. When the drive assembly 2 rotates, the spiral blade A205 compresses the liquid to flow upward or downward, thereby improving the heat exchange efficiency. The inner wall of the outer cylinder 104 is welded with a spiral blade B19, which forces the refrigerant to spiral upward in the jacket 20, thereby increasing the heat exchange area and the residence time of the refrigerant.

[0021] Mechanical seal 16 is a standard 108U type structure, including stationary ring 161, rotating ring 162, cage 163, compression spring B164, positioning sleeve 165 and set screw B18.

Claims

1. A wastewater resource utilization treatment device for metribuzin production, comprising a crystallization tank (1), characterized in that: The crystallization vessel (1) is equipped with a stirrer, and the stirrer is equipped with a central refrigerant circulation system. The crystallization vessel (1) is composed of a cover plate (101), a bottom plate (102), an inner cylinder (103), annular plate (105) and an outer cylinder (104). The annular space of the inner cylinder (103) and the outer cylinder (104) is equipped with a pipe wall refrigerant circulation system. The inner wall of the crystallization vessel (1) is equipped with a scraping assembly (4). The scraping assembly (4) is controlled to move up and down by a drive assembly (2). The drive assembly (2) is driven to rotate by the stirrer. The stirrer includes a geared motor (13) and a stirring paddle (3). The geared motor (13) and the stirring paddle (3) are connected by a coupling (6). The coupling (6) is equipped with a vibration knocking assembly.

2. The wastewater resource utilization treatment equipment for metribuzin production according to claim 1, characterized in that: The inner cylinder (103), outer cylinder (104), ring plate (105) and bottom plate (102) are welded into a closed annular jacket (20). The cover plate (101) is connected to the jacket (20) by sealing ring and bolts. The bottom of the outer cylinder (104) is provided with a refrigerant inlet pipe B (10) and the upper part of the outer cylinder (104) is provided with a refrigerant outlet pipe B (9). The jacket (20), refrigerant inlet pipe B (10) and refrigerant outlet pipe B (9) form a pipe wall refrigerant circulation system. A refrigerant inlet pipe A (8) is welded to the center of the bottom plate (102). The refrigerant inlet pipe A (8) extends into the crystallizer (1). The bottom plate (102) is provided with a discharge pipe (12), and the cover plate (101) is provided with a feed pipe (11). The stirring paddle (3) includes a stirring shaft (301), and several blades (302) are provided on the outside of the stirring shaft (301). The blades (302) are hollow. The stirring shaft (301) has an internal flow hole (305) from bottom to top. The blades (302) are provided with a baffle (303) inside. The baffle (303) is connected to the inner wall of the blade (302) on both sides. There is a space between the outer side of the baffle (303) and the inner wall of the blade (302). The internal flow hole (305) connects the internal space of each blade (302). The lower part of the stirring shaft (301) is rotatably sealed to the refrigerant inlet pipe A (8) through a mechanical seal (16). The upper part of the stirring shaft (301) is rotatably connected to the cover plate (101) through a mechanical seal (16). The upper part of the stirring shaft (301) has a side hole (304). The refrigerant outlet pipe A (7) is fixedly installed on the cover plate (101) and the refrigerant outlet pipe A (7) is provided with a bypass sleeve (701) on one side. The bypass sleeve (701) is located outside the side hole (304). The inner hole of the bypass sleeve (701) has a slot (702) and the slot (702) is connected to the inner hole of the refrigerant outlet pipe A (7). The upper and lower sides of the bypass sleeve (701) are rotatably connected to the stirring shaft (301) through the mechanical seal (16). The upper part of the stirring shaft (301) is connected to the geared motor (13) through the coupling (6). The geared motor (13) is fixedly connected to the stirring support (5). The stirring support (5) is fixedly connected to the cover plate (101). The refrigerant inlet pipe A (8), the refrigerant outlet pipe A (7) and the stirring paddle (3) form a central refrigerant circulation system.

3. The wastewater resource utilization treatment equipment for metribuzin production according to claim 1, characterized in that: The drive assembly (2) includes a top plate (201), a raised tube (206) at the center of the top plate (201), the raised tube (206) being connected to the stirring shaft (301) by a set screw A (17), a ring of vertical ribs (203) being welded to the outer circle of the top plate (201), a ground ring (202) being welded to the lower part of the vertical ribs (203), a raised ring (207) being provided at the lower part of the ground ring (202), and a ring groove being machined on the bottom plate (102). (1021), the raised ring (207) is rotatably connected to the ring groove (1021), and a helical rack (204) is welded to the outside of the vertical rib (203). The cross section of the helical rack (204) is a 60° tooth tip structure. The helical rack (204) covers the height of the vertical rib (203) from top to bottom. The continuous upper and lower helical racks (204) form a male thread structure. The continuous upper and lower helical racks (204) do not contact each other. The scraping assembly (4) includes a nut (401), the inner hole of which is machined with a helical toothed groove (4012). The cross-section of the helical toothed groove (4012) is a 60° tooth tip structure. The helical toothed groove (4012) forms a female thread structure. The pitch and tooth tip size of the helical toothed groove (4012) match the helical rack (204). The outer circle of the nut (401) is machined with an annular groove (4011). The groove (4011) contains... A scraper ring (402) is installed. The scraper ring (402) has a spiral structure with more than 1 spiral turns. A countersunk hole (4013) is evenly distributed around the circumference on the groove (4011). A compression spring A (403) is installed in the countersunk hole (4013). The outer end of the compression spring A (403) is welded to the inner hole of the scraper ring (402). The scraper ring (402) is in contact with the inner cylinder (103), and the compression spring A (403) is in a compressed state.

4. The wastewater resource utilization treatment equipment for metribuzin production according to claim 1, characterized in that: The coupling (6) includes a clamping sleeve (601), a rubber block (602), and a clamping shaft (603). The clamping sleeve (601), the rubber block (602), and the clamping shaft (603) form a plum blossom connector. The clamping shaft (603) is fixedly connected to the geared motor (13). The clamping sleeve (601) is fixedly connected to the stirring shaft (301). A protrusion (6011) is provided on one side of the clamping sleeve (601). The protrusion (6011) has a notch (6012) in the opposite direction of rotation. An elastic column (15) is fixedly connected to the stirring support (5). An impact ball (14) is fixedly connected to the other end of the elastic column (15). When the protrusion (6011) rotates, it can contact the impact ball (14). The coupling (6), the elastic column (15), the impact ball (14), and the stirring support (5) form a vibration and striking assembly.

5. The wastewater resource utilization treatment equipment for metribuzin production according to claim 3, characterized in that: The inner side of the vertical rib (203) is welded with a spiral blade A (205).

6. The wastewater resource utilization treatment equipment for metribuzin production according to claim 1, characterized in that: The inner wall of the outer cylinder (104) is welded with a helical blade B (19).

7. The wastewater resource utilization treatment equipment for metribuzin production according to claim 1, characterized in that: The mechanical seal (16) is a conventional 108U type structure, including a stationary ring (161), a rotating ring (162), a cage (163), a compression spring B (164), a positioning sleeve (165), and a set screw B (18).

8. The wastewater resource utilization treatment equipment for metribuzin production according to claim 2, characterized in that... Includes the following steps: The geared motor (13) rotates forward and reverse alternately, and the forward and reverse rotation times of the geared motor (13) are the same.

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