Water inlet ball valve of pumped storage power station

Abstract

The invention provides a water inlet ball valve of a pumped storage power station, and relates to the field of water inlet ball valves, the water inlet ball valve comprises a valve body, a built-in valve is arranged in the valve body, one end of the valve body is provided with an upstream connecting pipe, the other end of the valve body is provided with a downstream connecting pipe, and a guide ring is connected between the upstream connecting pipe and the valve body; and a telescopic joint is arranged at the other end of the valve body. Through the unique structural design of the four-way valve and the two cavities, after upstream high-pressure water is subjected to desilting, filtering and other treatment, purified water is alternately conveyed into the different cavity A and the cavity B, then water pressure is used for controlling cooperation of the water sealing ring and the water sealing ring, and separation control over sealing and valve opening and closing is achieved; the sand settling tank and the filter are arranged between the upstream water intake pipe and the downstream water intake pipe, so that impurities such as silt in the upstream water intake pipe can be effectively removed, and water entering the four-way valve and a subsequent control pipeline is kept clean.

Description

Technical Field

[0001] The invention relates to the field of water inlet ball valves, and in particular to a water inlet ball valve for a pumped storage power station. Background Art

[0002] In modern electric energy, pumped storage power stations play an extremely important role. They can pump water from the lower reservoir to the upper reservoir for storage when the power load is low, and release water to generate electricity when the power load is peak, effectively regulating the balance of power supply and demand and ensuring the stable operation of the power grid. Among them, the water inlet ball valve, as one of the key equipment in the water delivery system of the pumped storage power station, is responsible for controlling the on and off of the high-pressure water flow and ensuring the sealing performance of the system. Its performance directly affects the operating efficiency, safety and reliability of the entire pumped storage power station.

[0003] Traditional water inlet ball valves have exposed many problems during long-term operation. On the one hand, in terms of sealing control, most use hydraulic oil as the control medium to drive the sealing structure. However, due to the harsh working environment of the water inlet ball valve, under the long-term action of high-pressure water, the hydraulic oil is very easy to leak and mix into the water, forming the phenomenon of oil mixed with water. This will not only lead to a decrease in sealing performance, cause water leakage accidents, and affect the normal operation of the power station, but also the leaked hydraulic oil will pollute the environment and increase the cost of environmental protection treatment. In addition, once the problem of oil mixed with water occurs, the maintenance process is complicated and time-consuming, and the entire sealing control system needs to be fully checked and cleaned, which seriously affects the power generation efficiency of the power station.

[0004] On the other hand, the valve switch and sealing process of the traditional water inlet ball valve are often interrelated and complex to control. This integrated control method makes it more difficult to troubleshoot and locate the fault when the equipment fails, and maintenance personnel need to spend a lot of time to analyze and determine whether the problem is with the valve switch mechanism or the sealing structure. Moreover, during the maintenance process, due to the correlation between the two, multiple components may need to be disassembled and adjusted at the same time, which further increases the maintenance workload and maintenance costs, and reduces the availability of the equipment.

[0005] Therefore, it is necessary to provide a new pumped storage power station water inlet ball valve to solve the above-mentioned technical problems. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a water inlet ball valve for a pumped storage power station.

[0007] The present invention provides a water inlet ball valve for a pumped storage power station, comprising: a valve body, a built-in valve is arranged inside the valve body, an upstream connecting pipe is arranged at one end of the valve body, a downstream connecting pipe is arranged at the other end of the valve body, a guide ring is installed and connected between the upstream connecting pipe and the valve body, a telescopic joint is arranged at the other end of the valve body, a pressure compensation joint is installed and connected between the downstream connecting pipe and the telescopic joint, a valve control switch is arranged outside the valve body, a rocker arm is fixedly connected to the valve control switch, a hydraulic cylinder is arranged at the middle position of the valve body, and the telescopic end of the hydraulic cylinder is connected to one end of the rocker arm; a sealing opening and closing mechanism, the sealing opening and closing mechanism comprises two water sealing rings, the two water sealing rings are respectively arranged at the left and right ends of the built-in valve, two sealing cavities are arranged inside the valve body, the two sealing cavities are symmetrically arranged at both sides of the built-in valve, water sealing rings are arranged in the two sealing cavities, external convex annular grooves are arranged on the side cavity walls of the two sealing cavities, and the side ring walls of the two water sealing rings are respectively arranged in the two external convex annular grooves, and liquid changing components are symmetrically arranged at both ends of the valve body.

[0008] Preferably, the cavity on one side of the two water sealing rings and the two external convex annular grooves is cavity A, and the cavity on the other side of the two water sealing rings and the two external convex annular grooves is cavity B.

[0009] Preferably, a main inlet pipe is provided on the side wall of the two cavities A, and the other ends of the two main inlet pipes extend to the outside of the valve body, and a secondary inlet pipe is provided on the side wall of the two cavities B, and the other ends of the two secondary inlet pipes extend to the outside of the valve body.

[0010] Preferably, a water pressure liquid extraction mechanism is provided between the upstream connecting pipe and the downstream connecting pipe, the water pressure liquid extraction mechanism includes an upstream water extraction pipe, a downstream water extraction pipe is provided on the outside of the downstream connecting pipe, water extraction joints are provided on the pipe walls of the upstream connecting pipe and the downstream connecting pipe, one end of the upstream water extraction pipe is connected to a water extraction joint, one end of the downstream water extraction pipe is connected to a water extraction joint, the other end of the downstream water extraction pipe is connected to the middle position of the upstream water extraction pipe, the other end of the upstream water extraction pipe is installed and connected with a sand settling tank, a first branch pipe is provided at the upper end of the sand settling tank, the other end of the first branch pipe is installed and connected with a filter, the filter is provided with a second branch pipe, the other end of the second branch pipe is installed and connected with a shut-off valve, the shut-off valve is provided with a third branch pipe, and the other end of the third branch pipe is installed and connected with a four-way valve.

[0011] Preferably, the fluid exchange assembly includes a main branch pipe, one end of the main branch pipe is connected to the pipe mouth of the main inlet pipe, the other end of the main branch pipe is connected to the four-way valve, and a secondary branch pipe is installed and connected at the pipe mouth of the secondary inlet pipe, and the other ends of the main branch pipe and the secondary branch pipe are both connected to the four-way valve.

[0012] Preferably, pressure gauges are provided at both ends of the upstream water intake pipe, and the two pressure gauges are symmetrically arranged at both ends of the connection between the downstream water intake pipe and the upstream water intake pipe.

[0013] Preferably, exhaust valves are provided on the pipe walls of the upstream connecting pipe and the downstream connecting pipe, bypass valves are provided on the pipe walls of the upstream connecting pipe and the downstream connecting pipe, and a bypass connecting pipe is installed and connected between the two bypass valves.

[0014] Preferably, a drain valve is installed and connected at the lower end of the sand settling tank.

[0015] Compared with the related art, the water inlet ball valve of a pumped storage power station provided by the present invention has the following beneficial effects:

[0016] 1. The present invention uses a unique four-way valve and two-cavity structural design, uses upstream high-pressure water to be processed by sedimentation, filtration, etc., and then alternately transports water to different cavities A and B, and then uses water pressure to control the coordination of the water sealing ring and the water sealing circle, thereby realizing the separate control of the seal and the valve switch. This design effectively avoids the problem of oil mixing with water in the traditional water inlet ball valve system, greatly improves the stability and reliability of the system operation, ensures that the high-pressure water source control process of the pumped storage power station will not cause failures due to medium mixing, and ensures the safety and continuity of the operation of the entire power station;

[0017] 2. The present invention reduces the reliance on complex mechanical structures and a large number of external power sources by using water pressure to assist in controlling the opening and closing of the water sealing ring. Compared with the traditional water inlet ball valve, only a small amount of structure needs to be added to achieve efficient water intake and sealing functions, which reduces the manufacturing cost and maintenance difficulty of the equipment. In addition, due to the relatively simple structure and easy operation, the failure rate of the equipment in the long-term operation process is significantly reduced, which further reduces the operating cost and improves the overall cost performance of the equipment.

[0018] 3. The present invention can effectively remove impurities such as silt in the upstream water intake by setting a sedimentation tank and a filter between the upstream water intake pipe and the downstream water intake pipe, so that the water entering the four-way valve and the subsequent control pipeline remains clean, which not only avoids the wear and blockage of the valve seal and the internal pipeline by impurities, prolongs the service life of the valve and related components, but also ensures the accuracy and stability of water pressure control, improves the accuracy and response speed of the water inlet ball valve to the high-pressure water source control, and ensures that the pumped storage power station can accurately and efficiently regulate the water flow under various working conditions;

[0019] 4. The present invention greatly facilitates the inspection and maintenance of the equipment by controlling the sealing process and the valve opening and closing process separately. When a sealing structure or a valve fails, the corresponding part can be inspected, repaired or replaced separately without large-scale disassembly and debugging of the entire water inlet ball valve system. This greatly shortens the equipment maintenance time, reduces the power station downtime caused by equipment maintenance, improves the operating efficiency and power generation benefits of the pumped storage power station, and also reduces the work intensity and technical difficulty of maintenance personnel, which is conducive to the long-term stable operation and management of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 One of the structural schematic diagrams of a preferred embodiment provided by the present invention;

[0021] Figure 2 A second structural schematic diagram of a preferred embodiment provided by the present invention;

[0022] Figure 3 for Figure 1 A schematic diagram of the internal structure of a preferred embodiment is shown;

[0023] Figure 4 for Figure 3 The structural schematic diagram of A shown;

[0024] Figure 5 for Figure 2 The structural schematic diagram of the water pressure liquid extraction mechanism shown;

[0025] Figure 6 for Figure 1 A schematic diagram of the front view of a preferred embodiment shown;

[0026] Figure 7 for Figure 1 A side structural schematic diagram of a preferred embodiment is shown.

[0027] Numbers in the figure: 1. valve body; 11. built-in valve; 12. expansion joint; 2. upstream connecting pipe; 21. guide ring; 3. downstream connecting pipe; 31. pressure compensation joint; 4. valve control switch; 41. rocker arm; 42. hydraulic cylinder; 5. water sealing ring; 51. water sealing ring; 52. cavity A; 53. cavity B; 54. main inlet pipe; 55. auxiliary inlet pipe; 6. upstream water intake pipe; 61. downstream water intake pipe; 62. water intake joint; 63. sand settling tank; 631. pressure gauge; 632. filter; 64. shut-off valve; 65. four-way valve; 66. main branch pipe; 67. auxiliary branch pipe; 7. exhaust valve; 71. bypass valve; 72. bypass connecting pipe; 8. sewage valve. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and implementation modes.

[0029] Please refer to Figures 1 to 7 A water inlet ball valve for a pumped storage power station comprises: a valve body 1, a built-in valve 11 is arranged inside the valve body 1, an upstream connecting pipe 2 is arranged at one end of the valve body 1, a downstream connecting pipe 3 is arranged at the other end of the valve body 1, a guide ring 21 is installed and connected between the upstream connecting pipe 2 and the valve body 1, an expansion joint 12 is arranged at the other end of the valve body 1, a pressure compensation joint 31 is installed and connected between the downstream connecting pipe 3 and the expansion joint 12, a valve control switch 4 is arranged outside the valve body 1, a rocker arm 41 is fixedly connected to the valve control switch 4, and a valve control switch 4 is provided at the middle section of the valve body 1. A hydraulic cylinder 42, the telescopic end of the hydraulic cylinder 42 is connected to one end of the rocker arm 41; a sealed opening and closing mechanism, the sealed opening and closing mechanism includes two water sealing rings 5, the two water sealing rings 5 ​​are respectively arranged at the left and right ends of the built-in valve 11, and the interior of the valve body 1 is provided with two sealed chambers, the two sealed chambers are symmetrically arranged on both sides of the built-in valve 11, and water sealing rings 51 are provided in the two sealed chambers, and external convex annular grooves are provided on the side chamber walls of the two sealed chambers, and the side ring walls of the two water sealing rings 51 are respectively arranged in the two external convex annular grooves, and liquid changing components are symmetrically provided at both ends of the valve body 1.

[0030] In the specific implementation process, Figure 3 and Figure 4 As shown, the cavity on one side of the two water sealing rings 51 and the two outer convex ring grooves is a cavity A52, and the cavity on the other side of the two water sealing rings 51 and the two outer convex ring grooves is a cavity B53.

[0031] It should be noted that: the four-way valve 65 is controlled to operate so that the water in the four-way valve 65 is transported to the cavity B53, and the cavity is filled with water so that the water sealing ring 51 moves away from the water sealing ring 5 on the corresponding side, thereby realizing the sealing opening;

[0032] The four-way valve 65 is controlled to move so that the water in the four-way valve 65 is transported to the cavity A52, and the cavity A52 is filled with water so that the water sealing ring 51 moves in the opposite direction and presses against the water sealing ring 5 on the corresponding side, thereby achieving a good seal inside the ball valve;

[0033] The water pressure is used to control the coordination between the water sealing ring 51 and the water sealing circle 5, thereby realizing the separate control of the sealing mechanism and the valve switch, effectively avoiding the problem of oil mixing with water in the traditional water inlet ball valve system, and greatly improving the stability and reliability of the system operation.

[0034] refer to Figure 3 and Figure 4 As shown, main inlet pipes 54 are provided on the side walls of the two cavities A52, and the other ends of the two main inlet pipes 54 extend to the outside of the valve body 1; auxiliary inlet pipes 55 are provided on the side walls of the two cavities B53, and the other ends of the two auxiliary inlet pipes 55 extend to the outside of the valve body 1.

[0035] It should be noted that the setting of the main inlet pipe 54 allows the water stored in the four-way valve 65 to be transported to the cavity A52, and the setting of the two auxiliary inlet pipes 55 allows the water stored in the four-way valve 65 to be transported to the cavity B53.

[0036] refer to Figure 1 and Figure 5 As shown, a hydraulic liquid extraction mechanism is provided between the upstream connecting pipe 2 and the downstream connecting pipe 3, and the hydraulic liquid extraction mechanism includes an upstream water extraction pipe 6, a downstream water extraction pipe 61 is provided on the outside of the downstream connecting pipe 3, water extraction joints 62 are provided on the pipe walls of the upstream connecting pipe 2 and the downstream connecting pipe 3, one end of the upstream water extraction pipe 6 is connected to a water extraction joint 62, one end of the downstream water extraction pipe 61 is connected to a water extraction joint 62, the other end of the downstream water extraction pipe 61 is connected to the middle position of the upstream water extraction pipe 6, and a sand settling tank 63 is installed and connected to the other end of the upstream water extraction pipe 6, a first branch pipe is provided at the upper end of the sand settling tank 63, a filter 632 is installed and connected to the other end of the first branch pipe, a second branch pipe is provided on the filter 632, a shut-off valve 64 is installed and connected to the other end of the second branch pipe, a third branch pipe is provided on the shut-off valve 64, and a four-way valve 65 is installed and connected to the other end of the third branch pipe.

[0037] It should be noted that: the high-pressure water is transported from the upstream connecting pipe 2 to the interior of the valve body 1, and at the same time, the high-pressure water taken from the upstream connecting pipe 2 is transported to the interior of the upstream water intake pipe 6, and the water in the upstream water intake pipe 6 then enters the grit tank 63, so that the silt in the intake water is settled in the water in the grit tank 63, and the intake water in the grit tank 63 enters the filter 632 for further filtration, and then the filtered water is transported to the interior of the four-way valve 65.

[0038] refer to Figure 4 and Figure 5 As shown, the fluid exchange component includes a main branch pipe 66, one end of the main branch pipe 66 is connected to the pipe mouth of the main inlet pipe 54, the other end of the main branch pipe 66 is connected to the four-way valve 65, and a secondary branch pipe 67 is installed and connected at the pipe mouth of the secondary inlet pipe 55, and the other ends of the main branch pipe 66 and the secondary branch pipe 67 are both connected to the four-way valve 65.

[0039] It should be noted that the opening and closing of the pipeline of the four-way valve 65 is controlled so that the water inside it can be transported to the inside of the main branch pipe 66 and the auxiliary branch pipe 67 respectively, and then alternately transported to the inside of the main inlet pipe 54 and the auxiliary inlet pipe 55.

[0040] refer to Figure 5 As shown, pressure gauges 631 are provided at both ends of the upstream water intake pipe 6 , and the two pressure gauges 631 are symmetrically arranged at both ends of the connection between the downstream water intake pipe 61 and the upstream water intake pipe 6 .

[0041] It should be noted that: the two pressure gauges 631 can be used to timely and clearly observe the water pressure at both ends of the connection between the downstream water intake pipe 61 and the upstream water intake pipe 6.

[0042] refer to Figure 1 and Figure 2 As shown, exhaust valves 7 are provided on the pipe walls of the upstream connecting pipe 2 and the downstream connecting pipe 3 , bypass valves 71 are provided on the pipe walls of the upstream connecting pipe 2 and the downstream connecting pipe 3 , and a bypass connecting pipe 72 is installed and connected between the two bypass valves 71 .

[0043] It should be noted that exhaust valves 7 are provided on the pipe walls of the upstream connecting pipe 2 and the downstream connecting pipe 3. The two exhaust valves 7 enable the gas to be discharged in time when the switch state inside the ball valve is maintained.

[0044] refer to Figure 5 and Figure 6 As shown, a drain valve 8 is installed and connected at the lower end of the sand settling tank 63.

[0045] It should be noted that the sewage valve 8 installed at the lower end of the sand settling tank 63 can be used to conveniently discharge impurities such as mud and sand accumulated in the sand settling tank 63 .

[0046] The working principle of a water inlet ball valve for a pumped storage power station provided by the present invention is as follows: when it is necessary to control the opening of the built-in valve 11, the four-way valve 65 is controlled in advance to move, so that the water stored in the four-way valve 65 is transported to the cavity B53, and the interior thereof is filled with water so that the water sealing ring 51 moves away from the water sealing ring 5 on the corresponding side, thereby realizing the sealed opening, and then the hydraulic cylinder 42 is controlled to work so that its telescopic end drives the rocker arm 41 to rotate, driving the valve control switch 4 to rotate, so as to realize the rotation of the built-in valve 11, thereby realizing the closing of the ball valve; when it is necessary to control the closing of the built-in valve 11, the hydraulic cylinder 42 is used to drive the rocker arm 41 to rotate, and the valve control switch 4 rotates in the opposite direction, so as to realize the reverse rotation of the built-in valve 11, thereby realizing the opening of the ball valve, and then the four-way valve 65 is controlled to move, so that the water stored in the four-way valve 65 is transported to the cavity A52, and the interior thereof is filled with water so that the water sealing ring 51 moves in the opposite direction and presses against the water sealing ring 5 on the corresponding side, thereby realizing a good sealing of the inside of the ball valve.

[0047] High-pressure water is transported from the upstream connecting pipe 2 to the interior of the valve body 1, so that the high-pressure water taken from the upstream connecting pipe 2 is transported to the interior of the upstream water intake pipe 6, and the water in the upstream water intake pipe 6 then enters the sand settling tank 63, so that the silt in the water is settled in the water of the sand settling tank 63, and the water in the sand settling tank 63 enters the filter 632 for further filtration, and then the filtered water is transported to the interior of the four-way valve 65 to control the opening and closing of the pipeline of the four-way valve 65, so that the water inside it alternately flows to the two main branches 66 or the auxiliary branches 67, so that the water is automatically filtered and distributed to the corresponding pipelines, and then alternately transported to different cavities A52 or cavities B53, so that the water pressure can be used to better assist in controlling the opening and closing of the water sealing ring 5 in the ball valve, and the water intake sealing effect in the ball valve can be achieved by adding a small amount of structure, which can effectively avoid the occurrence of oil mixing with water in the water inlet ball valve system, and ensure that it will not affect the operation of the entire system. The sealing process and the valve opening and closing process are controlled separately, which is also convenient for inspection and maintenance, beneficial to the operation of the water inlet ball valve system, and greatly increases the overall service life of the water inlet ball valve.

[0048] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A water inlet ball valve for a pumped storage power station, characterized in that: include: A valve body (1), wherein a built-in valve (11) is provided inside the valve body (1), an upstream connecting pipe (2) is provided at one end of the valve body (1), a downstream connecting pipe (3) is provided at the other end of the valve body (1), a guide ring (21) is installed and connected between the upstream connecting pipe (2) and the valve body (1), an expansion joint (12) is provided at the other end of the valve body (1), a pressure compensation joint (31) is installed and connected between the downstream connecting pipe (3) and the expansion joint (12), a valve control switch (4) is provided outside the valve body (1), a rocker arm (41) is fixedly connected to the valve control switch (4), a hydraulic cylinder (42) is provided at the middle section of the valve body (1), and the telescopic end of the hydraulic cylinder (42) is connected to one end of the rocker arm (41); A sealing opening and closing mechanism, the sealing opening and closing mechanism comprises two water sealing rings (5), the two water sealing rings (5) are respectively arranged at the left and right ends of the built-in valve (11), the interior of the valve body (1) is provided with two sealing chambers, the two sealing chambers are respectively symmetrically arranged on the two sides of the built-in valve (11), the two sealing chambers are both provided with water sealing rings (51), the side chamber walls of the two sealing chambers are both provided with external convex annular grooves, the side ring walls of the two water sealing rings (51) are respectively arranged in the two external convex annular grooves, and the two ends of the valve body (1) are symmetrically provided with liquid replacement components.

2. A pumped storage power station water inlet ball valve according to claim 1, characterized in that: The cavity on one side of the two water sealing rings (51) and the two external convex annular grooves is a cavity A (52), and the cavity on the other side of the two water sealing rings (51) and the two external convex annular grooves is a cavity B (53).

3. A pumped storage power station water inlet ball valve according to claim 2, characterized in that: A main inlet pipe (54) is provided on the side wall of the two cavities A (52), and the other ends of the two main inlet pipes (54) extend to the outside of the valve body (1); and a secondary inlet pipe (55) is provided on the side wall of the two cavities B (53), and the other ends of the two secondary inlet pipes (55) extend to the outside of the valve body (1).

4. A pumped storage power station water inlet ball valve according to claim 3, characterized in that: A hydraulic liquid extraction mechanism is provided between the upstream connecting pipe (2) and the downstream connecting pipe (3), the hydraulic liquid extraction mechanism comprising an upstream water extraction pipe (6), a downstream water extraction pipe (61) is provided outside the downstream connecting pipe (3), water extraction joints (62) are provided on the pipe walls of the upstream connecting pipe (2) and the downstream connecting pipe (3), one end of the upstream water extraction pipe (6) is connected to a water extraction joint (62), one end of the downstream water extraction pipe (61) is connected to a water extraction joint (62), and the downstream water extraction pipe (6 1) is connected to the middle position of the upstream water intake pipe (6), the other end of the upstream water intake pipe (6) is connected to a sand settling tank (63), a first branch pipe is provided at the upper end of the sand settling tank (63), the other end of the first branch pipe is connected to a filter (632), the filter (632) is provided with a second branch pipe, the other end of the second branch pipe is connected to a shutoff valve (64), the shutoff valve (64) is provided with a third branch pipe, the other end of the third branch pipe is connected to a four-way valve (65).

5. A pumped storage power station water inlet ball valve according to claim 4, characterized in that: The liquid exchange assembly comprises a main branch pipe (66), one end of which is connected to the pipe opening of the main inlet pipe (54), the other end of which is connected to a four-way valve (65), a secondary branch pipe (67) is installed and connected at the pipe opening of the secondary inlet pipe (55), and the other ends of the main branch pipe (66) and the secondary branch pipe (67) are both connected to the four-way valve (65).

6. A pumped storage power station water inlet ball valve according to claim 4, characterized in that: Pressure gauges (631) are provided at both ends of the upstream water intake pipe (6), and the two pressure gauges (631) are symmetrically arranged at both ends of the connection between the downstream water intake pipe (61) and the upstream water intake pipe (6).

7. A pumped storage power station water inlet ball valve according to claim 1, characterized in that: An exhaust valve (71) is provided on the pipe wall of the upstream connecting pipe (2) and the downstream connecting pipe (3), a bypass valve (71) is provided on the pipe wall of the upstream connecting pipe (2) and the downstream connecting pipe (3), and a bypass connecting pipe (72) is installed and connected between the two bypass valves (71).

8. The water inlet ball valve of a pumped storage power station according to claim 4, characterized in that: A sewage discharge valve (8) is installed and connected at the lower end of the sand settling tank (63).

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