Waterproof hammer horizontal water tank device and control method

Abstract

The invention provides a waterproof hammer horizontal type water tank device and a control method, the waterproof hammer horizontal type water tank device comprises a horizontal type water supplementing tank, a water inlet pipeline of the horizontal type water supplementing tank is provided with a flowmeter and a first service valve, and a water outlet pipeline of the horizontal type water supplementing tank is provided with a second service valve; at least one safety valve and at least two air valves are arranged at the top of the horizontal water replenishing tank, and at least one drainage ball valve is arranged at the bottom of the horizontal water replenishing tank; the horizontal water replenishing tank is connected with the water inlet pipeline and the water outlet pipeline through flanges, and expansion joints are respectively arranged between the flanges on the water inlet pipeline and / or the water outlet pipeline and the flanges of the horizontal water replenishing tank. Aiming at the problem of negative water hammer in the water conveying pipeline, the horizontal water replenishing tank replenishes water to the pipeline when the pump is stopped in an accident, so that the water hammer fluctuation of the pipeline is stable, and the minimum pressure value which cannot be controlled in the water conveying pipeline is effectively avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of water conservancy and hydropower engineering, and in particular relates to a horizontal water tank device preventing water hammer and a control method thereof. Background Art

[0002] Water hammer is extremely harmful in long-distance water pipeline projects. It will cause serious vibration and damage to the water supply system and is the main factor causing pipe burst accidents. Therefore, long-distance pipeline systems should be designed with comprehensive water hammer protection technology. At present, water hammer protection measures are generally divided into hydraulic protection measures and mechanical protection measures or a combination of the two. Hydraulic water hammer protection measures mainly include air tanks, two-way pressure stabilizing towers, high water pools, etc. Mechanical protection measures mainly include air valves, pressure relief valves, pressure fluctuation pre-stop valves, etc.; combined protection measures mainly include one-way towers, air tanks with check valves, etc. Different water hammer protection measures have their own advantages and disadvantages. Air valves are most widely used in water diversion projects, mainly because they are inexpensive and easy to install and replace, but they also have the disadvantage that it takes a long time to restore water supply due to air intake; there are two-way surge chambers with free water surfaces or one-way surge towers for replenishing water to tunnels, but although the two-way surge tower has the best water hammer reflection effect, some projects may require a higher two-way surge tower, which is more difficult to use in areas with landscape requirements; the one-way surge tower can be highly controlled, but the entire system is relatively complex, consisting of a water tank, a check valve, an isolation valve, a water level control valve, a water level controller (such as a float) and a water level monitoring device, and if the check valve cannot be opened, the effect of preventing water hammer cannot be achieved, and the one-way surge tower can only replenish water to the tunnel to improve the minimum pressure along the water transmission line, but cannot improve the maximum internal water pressure value along the water transmission line; the air tank has a better effect in preventing water hammer, not only can it protect against positive pressure, but also can protect against negative pressure, but the air tank is troublesome to operate and maintain, and is generally large in size and expensive.

[0003] In general, although there are many water hammer prevention measures at present, they all have various shortcomings. Due to the limitations of cost, installation location, system complexity and other conditions, they cannot play a good role in water hammer protection. Therefore, it is urgent to design a water hammer horizontal water tank device to meet the water hammer protection requirements in long-distance water supply projects, while improving the stability of the water supply system, making it easy to install and having high economic benefits. Summary of the invention

[0004] The first object of the present invention is to provide a horizontal water tank device that is anti-water hammer.

[0005] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0006] A horizontal water tank device to prevent water hammer includes a horizontal water supply tank, a flow meter and a first inspection valve are provided on the water inlet pipe of the horizontal water supply tank, and a second inspection valve is provided on the water outlet pipe of the horizontal water supply tank; at least one safety valve and at least two air valves are provided on the top of the horizontal water supply tank, and at least one drain ball valve is provided on the bottom of the horizontal water supply tank; the horizontal water supply tank is connected to the water inlet and outlet pipes via flanges, and expansion joints are provided between the flanges on the water inlet pipe and / or the water outlet pipe and the flange of the horizontal water supply tank. The expansion joint can support the axial pressure of the pipeline, and can be freely expanded and contracted within the allowable expansion amount of the pipeline, so that the pipeline and the water supply tank become a whole, and have a certain displacement, which is convenient for installation. In this way, it can be adjusted according to the on-site installation size during installation and maintenance, which not only improves the work efficiency during work, but also plays a certain protective role for the pipeline equipment.

[0007] The horizontal water replenishment tank has a low height, is easy to operate, has no site restrictions, has strong stability and is simple to install.

[0008] The horizontal water supply tank is full of water during normal operation and has good sealing properties, which improves water delivery efficiency and protects water quality from external pollution.

[0009] At least two air valves can improve the reliability of air intake and exhaust and ensure the normal and smooth operation of the device.

[0010] The flow meter is arranged on the water inlet pipe to monitor the pipeline flow during the process of eliminating water hammer.

[0011] There are two inspection valves, which makes it convenient for staff to carry out daily inspection and maintenance of the water supply tank.

[0012] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0013] As a preferred technical solution of the present invention: the total volume of the horizontal water tank is initially selected according to the following formula:

[0014]

[0015] In the above formula: V is the total volume of the water supply tank, m 3 ; Q is the design flow rate, m 3 / s; H is the pump head, m; h f is the head loss, m; L i is the length of each section of the pressure pipeline, m; T a is the inertia time constant of the water pump, s; v i is the flow velocity in each pipe section, m / s; g is the acceleration due to gravity, m / s 2 ;H pis the design water head, m; the total volume of the water tank is ultimately determined according to the calculation results of the hydraulic transition process that meets the pressure bearing capacity of the pipeline.

[0016] As a preferred technical solution of the present invention: the diameters of the air valve inlet and the air valve outlet are initially selected according to the following formula:

[0017] D in =Aα

[0018]

[0019] In the above formula: A is the area of ​​the water pipeline, m2; α is the coefficient, which is generally 1 / 8 to 1 / 10; D in is the diameter of the air inlet, m; D out is the air valve outlet diameter, m; the air valve inlet diameter and outlet diameter are ultimately determined according to the hydraulic transition process calculation results that meet the pipeline pressure bearing capacity.

[0020] As a preferred technical solution of the present invention: the distance between the connection position between the horizontal water replenishment tank and the water inlet and outlet pipes and the bottom of the horizontal water replenishment tank is 1 / 5 of the distance from the top to the bottom of the horizontal water replenishment tank, which can ensure that the water body can be automatically renewed during steady-state operation and can fully replenish water during hydraulic transients.

[0021] Another object of the present invention is to provide a control method for the waterproof hammer-proof horizontal water tank device described above.

[0022] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0023] The control method of the horizontal water tank device for preventing water hammer as described above comprises the following steps:

[0024] During steady-state operation: the horizontal water supply tank is full of water, the air valve is closed, and the sealing is good. The horizontal water supply tank will not leak into the atmosphere. The distance between the connection position of the horizontal water supply tank and the water inlet and outlet pipes and the bottom of the horizontal water supply tank is 1 / 5 of the distance from the top to the bottom of the horizontal water supply tank. Water can easily flow in and out of the horizontal water supply tank, and the water body can be automatically renewed to ensure the water quality.

[0025] When the pump is stopped due to an accident: the pressure in the pipeline will drop suddenly. When the pressure drops to negative pressure, the water column will be broken. When the pressure reduction wave is transmitted to the horizontal water supply tank, the air valve will replenish air into the horizontal water supply tank, so that an air cushion will be formed in the horizontal water supply tank. At this time, the pressure in the horizontal water supply tank is greater than the pressure in the pipeline, which will cause water to be replenished into the pipeline. At this time, due to the replenishment of water, the water flow in the pipeline will not be broken and no cavity will be generated, which effectively avoids the uncontrollable minimum pressure value in the water supply pipeline and ensures that the water supply pipeline is always in a full flow state to avoid the formation of inflated air masses in the pipeline;

[0026] After the pump is stopped due to an accident: after the pressure reduction wave is transmitted, there will be a pressure increase wave, and the water will flow back along the water pipeline. Due to the closure of the valve behind the pump, a certain pressure rise will occur. At this time, the water will flow into the horizontal water supply tank, and the gas will be slowly exhausted through the air outlet of the air valve, which will produce a certain air cushion effect, which can effectively improve the excessive pressure rise in the water supply pipeline and the horizontal water supply tank;

[0027] As the air valve's air replenishment and exhaust processes alternate continuously, water flows between the water replenishment tank and the water pipeline. Due to the impedance of the water pipeline, it gradually becomes stable, and eventually the water hammer fluctuations of the entire pipeline become stable.

[0028] The present invention provides a horizontal water tank device and control method for preventing water hammer, which are used in long-distance water diversion projects to prevent water hammer. In view of the negative water hammer problem in the water pipeline, the horizontal water replenishment tank replenishes water to the pipeline when the pump stops due to an accident, so that the pipeline water hammer fluctuation is stable, and the uncontrollable minimum pressure value in the water pipeline is effectively avoided. Compared with the prior art, it has the following beneficial effects:

[0029] 1) The present invention solves the problem of negative water hammer at local high points caused by flow changes during the operation of the water supply pipeline, and has a good effect in preventing negative water hammer.

[0030] 2) The waterproof hammer-proof horizontal water tank device provided by the present invention has no moving parts, high reliability and low maintenance cost.

[0031] 3) The waterproof hammer-proof horizontal water tank device provided by the present invention is small in size, has an independent structure, good sealing performance, antifreeze properties of the water tank water, and has strong environmental adaptability.

[0032] 4) The horizontal water replenishment tank in the waterproof hammer-proof horizontal water tank device provided by the present invention has a low height, is easy to operate, has no site restrictions, has strong stability, and is easy to install. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a diagram showing the overall structure of the horizontal water tank device for preventing water hammer provided by the present invention;

[0034] In the figure: 1-flow meter; 21-first inspection valve; 22-second inspection valve; 3-safety valve; 41-first air valve; 42-second air valve; 5-drain ball valve; 6-horizontal water supply tank; 7-expansion joint. DETAILED DESCRIPTION

[0035] The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

[0036] The present invention provides a horizontal water tank device that prevents water hammer, which replenishes water to the pipeline when the pump stops due to an accident, effectively avoiding the generation of an uncontrollable minimum pressure value in the water pipeline; and the device is an independent structure, which is easy to install.

[0037] The waterproof hammer-proof horizontal water tank device mainly includes a flow meter 1, a first inspection valve 21 and a second inspection valve 22, a safety valve 3, a first air valve 41 and a second air valve 42, a drain ball valve 5 and a horizontal water supply tank 6. The top of the horizontal water supply tank 6 is provided with a safety valve 3, a first air valve 41 and a second air valve 42, and the bottom of the horizontal water supply tank 6 is provided with a drain ball valve 5. The connection mode of the horizontal water supply tank 6 and the pipeline is flange connection, and an expansion joint 7 is provided between the two flanges. It is easy to install and disassemble, and has good sealing performance.

[0038] The flow meter 1 monitors the flow in the pipeline during the water hammer elimination process, which is convenient for monitoring personnel to manage the equipment. The first inspection valve 21 and the second inspection valve 22 located on the inlet and outlet water delivery pipelines are convenient for the staff to maintain and repair the horizontal water supply tank 6.

[0039] When the pressure in the device is lower than the atmospheric pressure, the first air valve 41 and the second air valve 42 inhale air, and when the pressure rises above the atmospheric pressure, the air is exhausted. During the exhaust process, when the water in the device is full, the valve can be automatically closed, and the water is not allowed to leak into the atmosphere. In other embodiments, the air valve can also be set to 3 or more to improve the reliability of the device and the efficiency of water replenishment in the pipeline, ensuring the overall good operation effect.

[0040] The drain ball valve 5 is at the bottom of the horizontal water supply tank 6. Its end profile and radius have an effective gravity discharge effect, ensuring that the smooth tapered hole and the ultra-close distance of the ball in the tank prevent water from accumulating at the valve inlet, which ensures smooth drainage.

[0041] The safety valve 3 is in a normally closed state under the action of external force. When the medium pressure in the horizontal water supply tank 6 rises to exceed the specified value, a special valve prevents the pressure from exceeding the specified value by discharging the medium outside the system, ensuring that no accidents occur due to excessive pressure, so that safety is guaranteed.

[0042] The horizontal water supply tank 6 has low height, convenient operation, unlimited site, strong stability and simple installation. The horizontal water supply tank 6 is full of water during normal operation, has good sealing performance, improves water delivery efficiency, and ensures that water quality is not polluted by the outside world.

[0043] The expansion joint 7 can support the axial pressure of the pipeline and can be freely expanded and contracted within the allowable expansion amount of the pipeline, so that the pipeline and the horizontal water supply tank 6 become a whole, and have a certain displacement, which is convenient for installation. During installation and maintenance, it can be adjusted according to the on-site installation size, which not only improves work efficiency, but also plays a certain protective role on pipeline equipment.

[0044] Specifically, the above-mentioned anti-water hammer horizontal water tank device is controlled in the following manner:

[0045] During steady-state operation, the horizontal water replenishment tank 6 is full of water, the air valve is closed, the sealing is good, the water will not leak into the atmosphere, and the connection position between the horizontal water replenishment tank 6 and the water inlet and outlet water delivery pipes is 1 / 5 of the distance from the top to the bottom of the horizontal water replenishment tank 6. Water can easily flow in and out of the horizontal water replenishment tank 6, so the water can be automatically renewed to ensure the water quality.

[0046] When the pump is stopped due to an accident, the pressure in the pipeline will drop suddenly. When the pressure drops to negative pressure, the water column will be broken. When the pressure reduction wave is transmitted to the position of the horizontal water supply tank 6, the first air valve 41 and the second air valve 42 will replenish air to the horizontal water supply tank 6, so that an air cushion is formed in the horizontal water supply tank 6. At this time, the pressure in the horizontal water supply tank 6 is greater than the pressure in the pipeline, which will cause water to be replenished into the pipeline. At this time, due to the replenishment of water, the water flow in the pipeline will not be broken and no cavity will be generated, which effectively avoids the generation of uncontrollable minimum pressure value in the water supply pipeline, and ensures that the water supply pipeline is always in a full flow state to avoid the formation of inflated air masses in the pipeline.

[0047] After the pump is stopped due to an accident, a pressure-increasing wave will be transmitted after the pressure-reducing wave, and the water will flow back along the water pipeline. Due to the closure of the valve behind the pump, a certain pressure rise will be caused. At this time, the water will flow into the horizontal water supply tank 6, and the gas will be slowly exhausted through the outlets of the first air valve 41 and the second air valve 42, which will produce a certain air cushion effect, which can effectively improve the excessive pressure rise in the water supply pipeline and the horizontal water supply tank 6.

[0048] As the air valve's air replenishment and exhaust processes alternate continuously, water flows between the water replenishment tank and the water pipeline. Due to the impedance of the water pipeline, it gradually becomes stable, and eventually the water hammer fluctuations of the entire pipeline become stable.

[0049] The above-mentioned specific implementation cases are used to illustrate the present invention and are only preferred embodiments of the present invention, rather than limiting the present invention. Any modifications, equivalent substitutions, improvements, etc. made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A horizontal water tank device to prevent water hammer, characterized in that: The anti-water hammer horizontal water tank device includes a horizontal water supply tank, a flow meter and a first inspection valve are provided on the water inlet pipe of the horizontal water supply tank, and a second inspection valve is provided on the water outlet pipe of the horizontal water supply tank; at least one safety valve and at least two air valves are provided on the top of the horizontal water supply tank, and at least one drain ball valve is provided on the bottom of the horizontal water supply tank; the horizontal water supply tank is connected to the water inlet and outlet pipes via flanges, and expansion joints are respectively provided between the flanges on the water inlet pipe and / or the water outlet pipe and the flange of the horizontal water supply tank.

2. The waterproof hammer-proof horizontal water tank device according to claim 1, characterized in that: The total volume of the horizontal water tank is initially selected according to the following formula: In the above formula: V is the total volume of the water supply tank, m 3 ; Q is the design flow rate, m 3 / s; H is the pump head, m; h f is the head loss, m; L i is the length of each section of the pressure pipeline, m; T a is the inertia time constant of the water pump, s; v i is the flow velocity in each pipe section, m / s; g is the acceleration due to gravity, m / s 2 ; H p is the design water head, m; the total volume of the water tank is ultimately determined according to the calculation results of the hydraulic transition process that meets the pressure bearing capacity of the pipeline.

3. The waterproof hammer-proof horizontal water tank device according to claim 1, characterized in that: The diameters of the air valve inlet and outlet are initially selected according to the following formula: D in =Aα In the above formula: A is the area of ​​the water pipeline, m2; α is the coefficient, which is generally 1 / 8 to 1 / 10; D in is the diameter of the air inlet, m; D out is the diameter of the air valve outlet, m; the diameters of the air valve inlet and the air valve outlet are ultimately determined according to the calculation results of the hydraulic transition process that meets the pressure bearing capacity of the pipeline.

4. The waterproof hammer-proof horizontal water tank device according to claim 1, characterized in that: The distance between the connection position of the horizontal water replenishment tank and the water inlet and outlet pipes and the bottom of the horizontal water replenishment tank is 1 / 5 of the distance between the top and the bottom of the horizontal water replenishment tank.

5. The control method of the waterproof hammer-proof horizontal water tank device according to claim 1, characterized in that: The method comprises the following steps: During steady-state operation: the horizontal water supply tank is full of water, the air valve is closed, and the sealing is good. The horizontal water supply tank will not leak into the atmosphere. The distance between the connection position of the horizontal water supply tank and the water inlet and outlet pipes and the bottom of the horizontal water supply tank is 1 / 5 of the distance from the top to the bottom of the horizontal water supply tank. Water can easily flow in and out of the horizontal water supply tank, and the water body can be automatically renewed to ensure the water quality. When the pump is stopped due to an accident: the pressure in the pipeline will drop suddenly. When the pressure drops to negative pressure, the water column will be broken. When the pressure reduction wave is transmitted to the horizontal water supply tank, the air valve will replenish air into the horizontal water supply tank, so that an air cushion will be formed in the horizontal water supply tank. At this time, the pressure in the horizontal water supply tank is greater than the pressure in the pipeline, which will cause water to be replenished into the pipeline. At this time, due to the replenishment of water, the water flow in the pipeline will not be broken and no cavity will be generated, which effectively avoids the uncontrollable minimum pressure value in the water supply pipeline and ensures that the water supply pipeline is always in a full flow state to avoid the formation of inflated air masses in the pipeline; After the pump is stopped due to an accident: after the pressure reduction wave is transmitted, there will be a pressure increase wave, and the water will flow back along the water pipeline. Due to the closure of the valve behind the pump, a certain pressure rise will occur. At this time, the water will flow into the horizontal water supply tank, and the gas will be slowly exhausted through the air outlet of the air valve, which will produce a certain air cushion effect, which can effectively improve the excessive pressure rise in the water supply pipeline and the horizontal water supply tank; As the air valve's air replenishment and exhaust processes alternate continuously, water flows between the water replenishment tank and the water pipeline. Due to the impedance of the water pipeline, it gradually becomes stable, and eventually the water hammer fluctuations of the entire pipeline become stable.

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