A cylindrical overflow surge tank structure for long-distance water transmission pipelines

Abstract

This invention provides a cylindrical overflow surge tank structure for long-distance water transmission pipelines, comprising an inlet mechanism, a pressure regulating mechanism, an outlet mechanism, an overflow mechanism, and a makeup water mechanism. The inlet mechanism includes a main inlet pipe and a surge tank inlet pipe, the latter comprising a horizontal inlet pipe and a vertical inlet pipe connected to each other. The pressure regulating mechanism includes a lower overflow weir and an overflow pool. The outlet mechanism includes an overflow pipe and a main outlet pipe. The main inlet pipe is connected to both the horizontal and vertical inlet pipes; the incoming flow, after entering the horizontal inlet pipe, bends vertically upwards into the vertical inlet pipe. A lower overflow weir is located at the top of the end of the vertical inlet pipe, and an overflow pool is located outside the vertical inlet pipe. An overflow mechanism is located at the top of the overflow pool. The makeup water mechanism is located between the beginning of the horizontal inlet pipe and the end of the overflow pipe. This invention can effectively block the propagation of water hammer waves between pipe sections. By setting up a makeup water device, it can prevent the pipeline from being pulled apart or damaged by air ingress when extreme negative water hammer waves occur.

Description

Technical Field

[0001] This invention relates to safety protection facilities for long-distance water transmission projects, specifically a cylindrical overflow pressure regulating tower structure for long-distance water transmission pipelines. Background Technology

[0002] In the study of long-distance, high-flow-rate, multi-branch water transmission pipelines with undulating gravity flow, water hammer protection is a core research issue for ensuring the safe operation of long-distance water transmission projects. Inadequate protective measures can lead to significant water hammer pressure. Therefore, conducting hydraulic transition analysis on water transmission pipelines (including multi-branch pipelines) and implementing economical and reasonable water hammer protection measures is particularly urgent and important.

[0003] For water hammer protection measures, commonly used methods include optimizing valve operation patterns, setting up pressure regulating chambers, pressure regulating towers, pressure relief valves, air tanks, and air valves. Regardless of the method used, for ultra-long water pipelines, it is also necessary to pay attention to the hazards caused by water hammer waves propagating along the entire pipeline when a local pipeline bursts. The commonly used water hammer protection measures are insufficient to effectively cut off the propagation of water hammer waves and prevent further escalation of the accident. To address this problem, the invention patent "An Overflow Pressure Regulating Tower and Pressure Regulating Method for Ultra-Long Gravity Flow Water Transport Systems" (CN 113063049 A) ​​proposes a pressure regulating tower structure to block the propagation of water hammer waves. It optimizes the design of an impedance-type pressure regulating tower by changing the bottom-connected structure of the main pipe to a top-connected structure. Specifically, the main pipe is arranged in a "U" shape, with an overflow pressure regulating tower installed at the top. While this pressure regulating tower can effectively block the propagation of water hammer waves, it has the following drawbacks:

[0004] 1. Because the pipeline is arranged in a "U" shape, the water flows down into the outflow vertical pipe after passing the elevation of the connecting horizontal pipe. The flow pattern in the outflow vertical pipe is complex, and air is easily mixed in after falling, which may lead to the risk of air mixing in the downstream pipeline.

[0005] 2. The upstream and downstream pipelines of this surge tank are arranged in a "U" shape. If a pressure drop wave, i.e. a negative water hammer, occurs upstream or downstream of the surge tank, the water level in the pipeline on the side with the negative pressure wave may drop. Due to the "U" shape arrangement, the water level in the pipeline on the other side is difficult to replenish in time, which can easily lead to pipeline cavitation and also easily cause the risk of air entering the pipeline. Summary of the Invention

[0006] This invention addresses water hammer protection measures in long-distance water transmission pipelines by proposing a cylindrical overflow pressure regulating tower structure. This structure divides the long-distance water transmission pipeline system into several independent pipe sections, effectively blocking the propagation of water hammer waves between each section. This prevents pressure wave propagation from causing local pipeline accidents to spread along the entire pipeline during normal or emergency transitions. Furthermore, by installing a water replenishment device, it can prevent the pipeline from being emptied during extreme negative water hammer waves or from being damaged by air ingress into the pipeline.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A cylindrical overflow surge tank structure for long-distance water transmission pipelines includes an inlet mechanism, a pressure regulating mechanism, an outlet mechanism, an overflow mechanism, and a water replenishment mechanism. The inlet mechanism includes an inlet main pipe and a surge tank inlet pipe, the surge tank inlet pipe including a horizontal inlet pipe and a vertical inlet pipe connected to each other. The pressure regulating mechanism includes a lower overflow weir and a lower overflow pool. The outlet mechanism includes a lower overflow pipe and an outlet main pipe. The inlet main pipe is connected to the horizontal and vertical inlet pipes. The incoming flow turns vertically upward after entering the horizontal inlet pipe and enters the vertical inlet pipe. A lower overflow weir is set at the top of the end of the vertical inlet pipe. The outside of the vertical inlet pipe is the lower overflow pool. An overflow mechanism is set at the top of the lower overflow pool. The overflow mechanism is used to achieve overflow at the top of the surge tank when positive water hammer occurs. The water flow in the lower overflow pool is connected to the outlet main pipe through the lower overflow pipe. The water replenishment mechanism is set between the beginning of the horizontal inlet pipe and the end of the lower overflow pipe. The water replenishment mechanism is used to replenish water when the pressure of the upstream or downstream pipeline is lower than a preset threshold.

[0009] Furthermore, the overflow mechanism includes an overflow weir, an overflow pool, and an overflow pipe. An overflow weir is provided at the top of the overflow pool. The overflow water flows into the overflow pool after passing through the overflow weir, and finally the overflow water is discharged through the overflow pipe.

[0010] Furthermore, the overflow pool is cylindrical above the top elevation of the vertical inlet pipe and cylindrical below the top elevation of the vertical inlet pipe.

[0011] Furthermore, the water replenishment mechanism includes a water replenishment pipe, a pressure sensor before the tower, a pressure sensor after the tower, a sensor cable, and an automatic control valve. The water replenishment pipe is connected between the beginning of the horizontal water inlet pipe and the end of the overflow pipe. A pressure sensor before the tower and a pressure sensor after the tower are respectively installed at the end of the horizontal water inlet pipe and the beginning of the overflow pipe. The pressure of the upstream or downstream pipeline detected by the pressure sensor before the tower and the pressure sensor after the tower is transmitted to the automatic control valve through the sensor cable. When the pressure of the upstream or downstream pipeline is lower than 2m head, the automatic control valve opens automatically, and the water replenishment pipe replenishes water to the upstream or downstream pipeline.

[0012] Furthermore, the diameter of the overflow pool is larger than the diameter of the pressure regulating tower inlet pipe.

[0013] Furthermore, water cushions are provided at the bottom of both the overflow pool and the external overflow pool to eliminate the energy of the overflowing and external water flows.

[0014] The beneficial effects of this invention are:

[0015] Compared with existing conventional surge tanks or surge tanks that block water hammer waves, the innovative features of this invention are:

[0016] 1. The inlet riser is vertically inserted into the pressure regulating tower to form a cylindrical overflow pressure regulating tower, which blocks the propagation of water hammer waves during the transition process and prevents local accidents from spreading throughout the pipeline;

[0017] 2. The cylindrical surge tank has a circular overflow inlet and an outlet outlet through the overflow pipe. Due to the large volume of the cylindrical surge tank, the overflow water flows into the cylindrical surge tank and is fully dissipated by the water cushion, resulting in a relatively stable flow pattern when it enters the overflow pipe.

[0018] 3. A water replenishment device is installed. When an extreme negative pressure wave occurs in the pipeline and the water level in the pressure regulating tower drops too low, the automatic control valve will open automatically, and the water replenishment pipe will replenish water to the upstream or downstream pipeline to avoid the pipeline from being pulled into a void during the transition process and the risk of air entering the pipeline. Attached Figure Description

[0019] Figure 1 This is a front view of a cylindrical overflow surge tank structure that blocks water hammer propagation and prevents water flow from running dry, according to an embodiment of the present invention.

[0020] Figure 2 This is a top view of a cylindrical overflow surge tank structure that blocks water hammer propagation and prevents water flow cavitation according to an embodiment of the present invention.

[0021] Figure 3 This is a side view of a cylindrical overflow pressure regulating tower structure that blocks water hammer propagation and prevents water flow from running dry, according to an embodiment of the present invention.

[0022] The reference numerals in the figure are described below:

[0023] 1-Inlet main pipe; 2-1-Horizontal inlet pipe 2-1; 2-2-Vertical inlet pipe; 3-Overflow weir; 4-Overflow pool; 5-Overflow pipe; 6-Outflow weir; 7-Outflow pool; 8-Outflow pipe; 9-Make-up water pipe; 10-Pressure sensor in front of tower; 11-Pressure sensor behind tower; 12-Sensor cable; 13-Automatic control valve; 14-Outlet main pipe. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Figures 1-3 These are front, top, and side views of a cylindrical overflow surge tank structure for blocking water hammer propagation and preventing water flow runoff according to an embodiment of the present invention. The cylindrical overflow surge tank structure includes five parts: an inlet mechanism, a pressure regulating mechanism, an outlet mechanism, an overflow mechanism, and a water replenishment mechanism.

[0026] The water inlet mechanism includes a main water inlet pipe 1 and a pressure regulating tower water inlet pipe. The pressure regulating tower water inlet pipe includes a horizontal water inlet pipe 2-1 and a vertical water inlet pipe 2-2. The main water inlet pipe 1 is connected to the horizontal water inlet pipe 2-1 and the vertical water inlet pipe 2-2. The diameters of the horizontal water inlet pipe 2-1 and the vertical water inlet pipe 2-2 are equal. The incoming flow turns vertically upward after entering the horizontal water inlet pipe 2-1 and then enters the cylindrical pressure regulating tower through the vertical water inlet pipe 2-2.

[0027] The pressure regulating mechanism includes an overflow weir 3 and an overflow pool 4. An overflow weir 3, a thin-walled annular weir, is located at the top of the end of the vertical inlet pipe 2-2. The overflow pool 4 is the core component of the pressure regulating mechanism. Above the top elevation of the vertical inlet pipe 2-2, it is cylindrical; below the top elevation, it is a cylindrical structure. Therefore, the overflow pool 4 is divided into a cylindrical overflow pool and a cylindrical overflow pool. When the water level in the overflow pool 4 is lower than the top elevation of the end of the vertical inlet pipe 2-2, the upstream flow falls from the top of the vertical inlet pipe 2-2 to the cylindrical overflow pool. However, when the water level in the overflow pool is higher than the top elevation of the end of the vertical inlet pipe 2-2, the upstream flow surges into the overflow pool 4 from the top of the vertical inlet pipe 2-2.

[0028] The water outlet mechanism includes an overflow pipe 5 and a main outlet pipe 14. The water flow in the overflow pool 4 eventually connects to the main outlet pipe 14 through the overflow pipe 5, indicating that the presence of the overflow pool 4 disrupts the continuity of the pipeline. The diameter of the overflow pool 4 is larger than the diameter of the pressure regulating tower inlet pipe.

[0029] The overflow mechanism includes an overflow weir 6, an overflow pool 7, and an overflow pipe 8. The overflow weir 6 is set at the top of the overflow pool 4. The overflow water flows through the overflow weir 6 and then enters the overflow pool 7. Finally, the overflow water is discharged through the overflow pipe 8. The function of the overflow mechanism is to achieve overflow at the top of the pressure regulating tower when positive water hammer occurs, thereby reducing the pipeline pressure.

[0030] The water replenishment mechanism includes a water replenishment pipe 9, a tower front pressure sensor 10, a tower rear pressure sensor 11, a sensor cable 12, and an automatic control valve 13. The water replenishment pipe 9 is connected to the beginning of the horizontal water inlet pipe 2-1 and the end of the overflow pipe 5. The tower front pressure sensor 10 and the tower rear pressure sensor 11 are installed at the end of the horizontal water inlet pipe 2-1 and the beginning of the overflow pipe 5, respectively. The pressure sensor data is transmitted to the automatic control valve 13 through the sensor cable 12. When the pressure sensor pressure is lower than 2m water head, the automatic control valve 13 automatically opens, and the water replenishment pipe 9 replenishes water to the upstream or downstream pipeline, avoiding the risk of pipeline cavitation and air intake during the transition process.

[0031] Both the bottom of the overflow pool 4 and the outer overflow pool 7 are equipped with water cushions to eliminate the energy of the overflow and outer water flow.

[0032] In the steady-state operation of the pipeline, the upstream water flow of the surge tank described in this invention passes through the horizontal inlet pipe 2-1 → vertical inlet pipe 2-2 → cylindrical overflow tank → overflow pipe 5 → main outlet pipe 14. To ensure stable flow and prevent overflow under various stable operating conditions, and to allow the pipeline to carry the design flow rate, the hydraulic gradient elevation of the vertical inlet pipe must be higher than the top elevation of the vertical inlet pipe 2-2 to ensure that the vertical inlet pipe 2-2 can carry the design flow rate under various stable operating conditions; however, its elevation must not be higher than the elevation of the surge tank's external overflow weir 6 to ensure that the surge tank does not overflow under stable operating conditions. Therefore, to ensure the normal operation of the pipeline under various operating conditions, appropriate top elevations of the vertical inlet pipe 2-2 and the external overflow weir 6 are required. The elevation of the top of the vertical inlet pipe 2-2 is determined as follows: the lowest elevation of the upstream inlet water level of the water conveyance system is selected, and the pipe roughness is maximized. When the pipeline uses the design flow rate, the hydraulic gradient line is at its lowest, and this elevation is the top elevation of the vertical inlet pipe 2-2. Under other normal operating conditions, the hydraulic gradient line rises to ensure overflow at the top of the vertical inlet pipe 2-2. The elevation of the top of the overflow weir 6 is determined as follows: the highest elevation of the upstream inlet water level of the water conveyance system is selected, and the pipe roughness is minimized. When the system branch outlet is closed and the main line uses the full design flow rate for overflow, the hydraulic gradient line is at its highest, and the surge tank overflows. This elevation is the top elevation of the overflow weir 6.

[0033] During the emergency closure transition of each control valve in the water conveyance system, when positive water hammer (i.e., pressure surge) occurs in the upstream and downstream pipelines, the water level in the surge tank rises. When it rises to the elevation of the overflow weir, it begins to overflow. The overflowing water relieves the rise in system pressure and blocks the positive water hammer from propagating upstream or downstream through the surge tank.

[0034] When control valves are opened or during a transition period following a local pipe burst, a pressure drop wave (negative water hammer) occurs in the upstream or downstream pipeline. This negative pressure wave propagates upstream and downstream along the pipeline, causing the pressure tower water level to drop. When the water level drops to the elevation of the vertical inlet pipe 2-2, the inflow and outflow are completely disconnected, blocking the propagation of the water hammer wave. Furthermore, when the pressure tower water level drops to the pipeline elevation, the upstream and downstream pipelines are prone to water cavitation. This invention provides a water supply pipe 9 connected to the beginning of the horizontal inlet pipe 2-1 and the end of the overflow pipe 5. Pressure sensors are installed at the end of the horizontal inlet pipe 2-1 and the beginning of the overflow pipe 5. The pressure sensor data is transmitted to the automatic control valve 13 via the sensor cable 12. When the pressure sensor pressure is lower than 2m head, the automatic control valve 13 automatically opens, and the water supply pipe 9 supplies water to the upstream or downstream pipeline, preventing pipeline cavitation and the risk of air intake during the transition period.

[0035] For long-distance, high-flow-rate, undulating gravity-flow, and multi-branch water pipelines, conventional water hammer protection research is a necessary condition for ensuring the safe operation of long-distance water transmission projects. In addition, under extreme accident conditions, such as emergency closure of branch control valves or localized pipe bursts, severe water hammer waves propagate along the entire pipeline, potentially paralyzing it and causing safety issues. Therefore, taking effective measures to prevent the propagation of water hammer waves throughout the pipeline is extremely important.

[0036] This invention provides a cylindrical overflow surge tank structure for long-distance water transmission pipelines, which divides the long-distance water transmission pipeline system into several independent pipe segments to block the propagation of water hammer waves throughout the pipeline. The surge tank of this invention has a cylindrical structure below the top of the vertical inlet pipe 2-2. This is achieved by raising the elevation of the upstream inlet pipe, with the vertical inlet pipe 2-2 extending vertically into the surge tank structure, thus forming a cylindrical lower section and a cylindrical upper section. Compared with existing surge tanks, the surge tank of this invention features a circular overflow weir 3, increasing the length of the overflow weir. The overflowing water falls onto the water cushion inside the cylindrical surge tank, effectively dissipating energy and quickly adjusting the flow pattern before entering the overflow pipe 5, avoiding the risk of undesirable flow patterns directly entering the downstream pipeline. This embodiment effectively blocks the propagation of water hammer waves between pipe segments; additionally, a water replenishment device is provided to prevent the pipeline from being pulled dry during extreme negative water hammer waves, which could lead to air mixing in the water and adversely affect the operation of the pressurized pipeline.

[0037] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A cylindrical overflow surge tower structure in a long distance water conveyance pipeline, characterized by: It includes an inlet mechanism, a pressure regulating mechanism, an outlet mechanism, an overflow mechanism, and a water replenishment mechanism; The water inlet mechanism includes the main water inlet pipe and the pressure regulating tower water inlet pipe. The pressure regulating tower water inlet pipe includes horizontal water inlet pipes and vertical water inlet pipes that are connected to each other. The pressure regulating mechanism includes an overflow weir and an overflow pool. The overflow pool is cylindrical above the top elevation of the vertical inlet pipe and cylindrical below the top elevation of the vertical inlet pipe. The overflow pool is divided into a cylindrical overflow pool and a cylindrical overflow pool. The water outlet mechanism includes a bottom overflow pipe and a main water outlet pipe; The main inlet pipe is connected to a horizontal inlet pipe and a vertical inlet pipe. After entering the horizontal inlet pipe, the incoming flow turns vertically upward and enters the vertical inlet pipe. An overflow weir is set at the top of the end of the vertical inlet pipe. The overflow weir is an annular thin-walled weir. The outside of the vertical inlet pipe is an overflow pool. An overflow mechanism is installed at the top of the overflow tank. The overflow mechanism is used to achieve overflow at the top of the pressure regulating tower when positive water hammer occurs. The water in the overflow tank is connected to the main outlet pipe through the overflow pipe. The water replenishment mechanism is located between the beginning of the horizontal inlet pipe and the end of the overflow pipe. The water replenishment mechanism is used to replenish water when the pressure of the upstream or downstream pipe is lower than a preset threshold. The water replenishment mechanism includes a water replenishment pipe, a pressure sensor before the tower, a pressure sensor after the tower, a sensor cable, and an automatic control valve. The water replenishment pipe is connected between the beginning of the horizontal water inlet pipe and the end of the overflow pipe. The pressure sensor before the tower and the pressure sensor after the tower are respectively installed at the end of the horizontal water inlet pipe and the beginning of the overflow pipe. The pressure of the upstream or downstream pipe detected by the pressure sensor before the tower and the pressure sensor after the tower is transmitted to the automatic control valve through the sensor cable. When the pressure of the upstream or downstream pipe is lower than 2m head, the automatic control valve opens automatically, and the water replenishment pipe replenishes water to the upstream or downstream pipe.

2. The cylindrical overflow surge tank structure in long distance water conveyance pipeline according to claim 1, characterized in that, The overflow mechanism includes an overflow weir, an overflow pool, and an overflow pipe. An overflow weir is set at the top of the overflow pool. The overflow water flows into the overflow pool after passing through the overflow weir, and finally the overflow water is discharged through the overflow pipe.

3. The cylindrical overflow surge tank structure in a long-distance water transmission pipeline according to claim 1, characterized in that, The diameter of the overflow pool is larger than the diameter of the inlet pipe of the pressure regulating tower.

4. The cylindrical overflow pressure regulating tower structure in a long-distance water transmission pipeline according to claim 2, characterized in that, Both the bottom of the overflow pool and the outer overflow pool are equipped with water cushions to eliminate the energy of the overflowing and outer overflowing water flows.

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