Drainage device of axial fan

Abstract

The invention belongs to the technical field of drainage of mechanical equipment, and discloses an axial fan drainage device which comprises a drainage tank, a communicating pipe and a drainage pipe. The top of the drainage tank is lower than the lowest position of the axial fan, a drainage valve is arranged at the bottom of the drainage tank, the height of the drainage tank meets the condition that h is larger than p / rhog, h is the height of the drainage tank, p is the absolute value of the maximum negative pressure value formed in the axial fan, rhog is the ponding density, and g is the gravitational acceleration. The first end of the communicating pipe is communicated with the axial fan, and the second end is communicated with the drain tank. The first end of the drainage pipe is communicated with the lowest position of the axial fan, and the second end is communicated with the drainage tank. The same negative pressure is kept in the drainage tank and the axial fan, accumulated water in the axial fan is discharged into the drainage tank through the drainage pipe under the action of gravity, after the liquid level of the accumulated water in the drainage tank reaches a certain height, the gravity of the accumulated water can overcome suction force formed by the negative pressure in the drainage tank, and the accumulated water can be smoothly discharged from the drainage valve at the bottom of the drainage tank.

Description

Technical Field

[0001] The invention relates to the technical field of drainage of mechanical equipment, and in particular to a shaft-added fan drainage device. Background Art

[0002] Thermal power plants are generally designed to install two shaft fans to extract the non-condensable steam in the shaft seal heater, one of which is in normal operation and the other is used as a standby. The outlet check valve of the standby shaft fan is closed, and the inlet manual door is opened to maintain the same negative pressure as the operating shaft fan. Non-condensable steam can enter the standby shaft fan housing through the inlet manual door and condense, forming water accumulation at the bottom of the standby shaft fan housing, and some condensed water will also penetrate into the standby shaft fan housing at the outlet check valve.

[0003] like Figure 1 As shown, in order to drain the accumulated water at the bottom of the shaft-added fan housing in time and ensure that the standby shaft-added fan can operate normally after being turned on, a drain pipe is provided at the lower part of the shaft-added fan housing, and a manual drain valve is installed on the drain pipe. Since the interior of the shaft-added fan housing is a negative pressure environment, the position of the manual drain valve should be lower than the bottom of the shaft-added fan housing, so that the gravity of the accumulated water in the drain pipe can overcome the negative pressure in the housing and the accumulated water can be discharged smoothly.

[0004] However, if the accumulated water in the drain pipe is mixed with air, and the water column and the air column are intertwined, the gravity of the accumulated water in the drain pipe is insufficient to overcome the negative pressure in the shell, and the accumulated water cannot be smoothly discharged from the bottom of the standby shaft plus fan shell, thereby affecting the normal operation of the standby shaft plus fan after it is turned on. Summary of the invention

[0005] The purpose of the present invention is to provide a shaft fan drainage device to solve the technical problem that the water accumulated at the bottom of the standby shaft fan cannot be discharged smoothly, which affects the normal operation of the standby shaft fan after it is turned on.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] The shaft fan drainage device is used to discharge the water accumulated inside the shaft fan, including:

[0008] A drain tank, the top of which is lower than the lowest point of the shaft fan, a drain valve is provided at the bottom of the drain tank, and the height of the drain tank satisfies h>|p| / ρg, where h is the height of the drain tank, |p| is the absolute value of the maximum negative pressure that can be formed inside the shaft fan, ρ is the water density, and g is the acceleration of gravity;

[0009] A connecting pipe, wherein a first end of the connecting pipe is connected to the shaft fan, and a second end of the connecting pipe is connected to the drain tank;

[0010] A drainage pipe, wherein the first end of the drainage pipe is connected to the lowest point of the shaft fan, and the second end of the drainage pipe is connected to the drain tank.

[0011] In one embodiment, the first end of the connecting pipe is connected to the top of the axial fan, and the second end of the connecting pipe is connected to the top of the drain tank.

[0012] In one embodiment, the connecting pipe includes a first pipe section, a second pipe section and a third pipe section, the first pipe section extends upward from the top of the shaft-added fan, the second pipe section connects the first pipe section and the third pipe section, and the third pipe section extends downward to connect with the top of the drain tank.

[0013] In one embodiment, the length of the first pipe section extending upward from the top of the shaft-added blower is 5 cm-15 cm.

[0014] In one embodiment, the drain tank is also provided with a liquid level meter.

[0015] In one embodiment, the liquid level meter is a remote liquid level meter.

[0016] In one embodiment, the drain valve is a solenoid valve, and the solenoid valve is communicatively connected to the liquid level meter.

[0017] In one embodiment, the second end of the drain pipe is located above the liquid level meter.

[0018] In one embodiment, the diameter of the drain tank is set to 5cm-10cm.

[0019] In one embodiment, the diameter of the connecting pipe is set to 6mm-10mm.

[0020] Beneficial effects of the present invention:

[0021] The present invention provides a drainage device for an axial fan, which is used to discharge the accumulated water inside the axial fan, and includes a drain tank, a connecting pipe and a drain pipe. The top of the drain tank is lower than the lowest point of the axial fan, and a drain valve is arranged at the bottom, and the height of the drain tank satisfies h>|p| / ρg, wherein h is the height of the drain tank, |p| is the absolute value of the maximum negative pressure that can be formed inside the axial fan, ρ is the density of accumulated water, and g is the acceleration of gravity. The first end of the connecting pipe is connected to the axial fan, and the second end is connected to the drain tank. The first end of the drain pipe is connected to the lowest point of the axial fan, and the second end is connected to the drain tank. The drain tank is connected to the inside of the axial fan through a connecting pipe, so that the inside of the drain tank and the inside of the axial fan maintain the same negative pressure. The accumulated water inside the axial fan can be smoothly discharged into the drain tank through the drain pipe under the action of gravity, and the height of the drain tank satisfies h>|p| / ρg, so that when the water level in the drain tank reaches a certain height, the gravity of the accumulated water can overcome the suction formed by the negative pressure inside the drain tank, and the accumulated water can be smoothly discharged from the drain valve at the bottom of the drain tank, avoiding the internal water accumulation from affecting the normal operation of the standby axial fan after it is turned on. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of a central axis plus fan drainage device in the prior art;

[0023] Figure 2 It is a schematic diagram of the structure of the shaft-added fan drainage device described in an embodiment of the present invention.

[0024] In the figure:

[0025] a. Shaft fan; b. Drain pipe; c. Manual drain valve; 1. Shaft fan; 2. Drain tank; 21. Drain valve; 22. Liquid level meter; 3. Connecting pipe; 4. Drain pipe. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar parts or parts having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0027] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, it can be a mechanical connection or an electrical connection, it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In the description of the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include the first feature being in direct contact with the second feature, or may include the first feature being in contact with the second feature through another feature between them instead of being in direct contact. Moreover, a first feature being "above", "above" and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0029] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0030] like Figure 1 As shown, in the prior art, the drainage device setting method of the shaft fan a is usually to set a drainage pipe b at the bottom of the shaft fan a, and a manual drainage valve c is set on the drainage pipe b. The staff controls the opening and closing of the manual drainage valve c to allow the accumulated water inside the shaft fan a to be discharged by its own gravity. However, since the interior of the shaft fan a is a negative pressure environment, it is easy to cause poor drainage.

[0031] like Figure 2 As shown, the present invention provides a drainage device for an axial fan, which is used to discharge the accumulated water inside the axial fan 1, and includes a drain tank 2, a connecting pipe 3 and a drainage pipe 4. The top of the drain tank 2 is lower than the lowest point of the axial fan 1, so that the axial fan 1 and the drain tank 2 form a certain height difference, so that the accumulated water inside the axial fan 1 can be smoothly discharged into the drain tank 2 to prevent the backflow of soda and water. A drain valve 21 is provided at the bottom of the drain tank 2, and the height of the drain tank 2 satisfies h>|p| / ρg, where h is the height of the drain tank 2, in m, |p| is the absolute value of the maximum negative pressure value that can be formed inside the axial fan 1, in Pa, and ρ is the density of accumulated water, in kg / m 3 , g is the acceleration due to gravity, in m / s 2 The first end of the connecting pipe 3 is connected to the shaft fan 1, and the second end is connected to the drain tank 2. The first end of the drain pipe 4 is connected to the lowest point of the shaft fan 1, and the second end is connected to the drain tank 2. Preferably, the top of the drain tank 2 is 40 cm lower than the lowest point of the shaft fan 1, so that the shaft fan 1 and the drain tank 2 form a certain height difference without making the drain pipe 4 too long to cause material waste.

[0032] The drain tank 2 is connected to the shaft fan 1 through the connecting pipe 3, so that the inside of the drain tank 2 and the shaft fan 1 maintain the same negative pressure. The accumulated water inside the shaft fan 1 can be smoothly discharged into the drain tank 2 through the drain pipe 4 under the action of gravity. The internal space of the drain tank 2 is more spacious than the drain pipe b. When the soda-water mixture is discharged into the drain tank 2, the flow rate drops suddenly, the pressure drops rapidly, the gas expands due to the pressure reduction, and gathers upward in the upper space of the drain tank 2. The liquid gathers at the bottom of the drain tank 2 due to inertia and gravity. The sudden expansion of space is used to achieve the separation of soda and water. The height of the drain tank 2 satisfies h>|p| / ρg, so that when the accumulated water level in the drain tank 2 reaches a certain height, the accumulated water's own gravity can overcome the suction formed by the negative pressure inside the drain tank 2, and the accumulated water can be smoothly discharged from the drain valve 21 at the bottom of the drain tank 2, avoiding the internal accumulated water from affecting the normal operation of the standby shaft fan 1 after it is turned on.

[0033] Specifically, let the cross-sectional area of ​​the water in the drain tank 2 be s, in m 2 , the trap 2 is a cylindrical tank, so the shape of the water inside it is a water column. The gravity of the water inside the trap 2 is G = Mg = ρshg, where M is the mass of the water, in kg; the suction force on the water formed by the negative pressure in the trap 2 is F = |p|s. When the gravity of the accumulated water is equal to the suction force on the accumulated water formed by the negative pressure in the trap 2, G = F, that is, ρhg = |p|, h = |p| / ρg. When the gravity of the accumulated water is greater than the suction force on the accumulated water formed by the negative pressure in the trap 2, h>|p| / ρg must be satisfied.

[0034] For example, the negative pressure inside the shaft fan 1 is generally -3000Pa to -4000Pa, and can reach -6000Pa in extreme cases. Taking the maximum negative pressure value that can be formed inside the shaft fan 1 as -6000Pa as an example, |p| is 6000Pa, and the gravity acceleration g is 10m / s 2 , the density of accumulated water is 1000kg / m 3 , at this time, the height of the drain tank 2 satisfies h>|p| / ρg, that is, the height of the drain tank 2 is greater than 0.6m. When the water level in the drain tank 2 is 0.6m, the gravity of a 0.6m high water column with a cross-sectional area of ​​s is 6000sN, and the atmospheric pressure of -6000Pa exerts a suction force of 6000sN on the water with a cross-sectional area of ​​s. The two work in opposite directions and can offset each other. Therefore, when the water level is greater than 0.6m, the gravity of the accumulated water itself can overcome the suction force formed by the negative pressure inside the drain tank 2, and the accumulated water can be smoothly discharged from the drain valve 21 at the bottom of the drain tank 2.

[0035] Preferably, if Figure 2As shown, the first end of the connecting pipe 3 is connected to the top of the axial fan 1, and the second end of the connecting pipe 3 is connected to the top of the drain tank 2, which can effectively prevent accumulated water from entering the connecting pipe 3 and affecting the connecting effect of the connecting pipe 3 on the axial fan 1 and the drain tank 2.

[0036] Specifically, the connecting pipe 3 includes a first pipe section, a second pipe section and a third pipe section, the first pipe section extends upward from the top of the shaft-added fan 1, the second pipe section connects the first pipe section and the third pipe section, and the third pipe section extends downward to communicate with the top of the drain tank 2. Such a structural design can effectively prevent the connecting pipe 3 from being blocked by foreign matter, thereby extending the service life of the connecting pipe 3. More specifically, the first pipe section extends vertically upward from the top of the shaft-added fan 1, and the third pipe section extends vertically downward to communicate with the top of the drain tank 2. Optionally, from the perspective of practical application, the length of the first pipe section extending vertically upward from the shaft-added fan 1 is preferably 5cm-15cm.

[0037] Furthermore, if Figure 2 As shown, the drain tank 2 is also provided with a liquid level meter 22 for monitoring the accumulated water level in the drain tank 2 so that the staff can control the opening and closing of the drain valve 21 according to the liquid level. Specifically, the liquid level meter 22 is connected to the drain tank 2 through two upper and lower connecting valves, respectively, so that the liquid level meter 22 can be replaced when it is damaged. Optionally, the liquid level meter 22 can be an on-site liquid level meter or a remote liquid level meter.

[0038] Preferably, the liquid level meter 22 is a remote liquid level meter, which can transmit the liquid level signal of the drain tank 2 to the distributed control system (DCS) of the thermal power plant. The drain valve 21 is a solenoid valve. The remote liquid level meter communicates with the solenoid valve through the distributed control system (DCS). The distributed control system (DCS) compares the liquid level signal with the preset drainage liquid level height and the drainage stop liquid level height, and then outputs a control signal to control the opening and closing of the solenoid valve to achieve the purpose of drainage or stopping drainage.

[0039] Still taking the maximum negative pressure value that can be formed inside the shaft fan 1 as -6000Pa as an example, the height of the steam trap 2 is greater than 0.6m, for example, the height of the steam trap 2 is set to 1m, the preset drainage liquid level height is set to 80cm, and the preset stop drainage liquid level height is set to 65cm. The preset stop drainage liquid level height is usually greater than the liquid level height when the gravity of the accumulated water is equal to the suction formed by the negative pressure inside the steam trap 2, to prevent the existence of impurities or bubbles in the steam trap 2, etc., the liquid level cannot drop to the preset stop drainage liquid level height, resulting in the electromagnetic valve being unable to close normally. When the liquid level in the steam trap 2 reaches 80cm, the distributed control system (DCS) issues a high liquid level alarm and opens the electromagnetic valve for drainage. When the liquid level in the steam trap 2 drops to 65cm, the distributed control system (DCS) issues a low liquid level alarm and closes the electromagnetic valve to stop drainage, so as to achieve automatic drainage of the steam trap 2. Furthermore, maintaining a certain liquid level height inside the drain tank 2 can act as a water seal, effectively isolating the interior of the shaft fan 1 and the space above the liquid level in the drain tank 2 from the atmosphere, so as to maintain a negative pressure environment inside the shaft fan 1.

[0040] Preferably, if Figure 2 As shown, the first end of the drain pipe 4 is connected to the lowest point of the shaft fan 1, and the water accumulated at the bottom of the shaft fan 1 can be smoothly discharged from the drain pipe 4 into the drain tank 2 to prevent incomplete drainage. The second end of the drain pipe 4 is located above the liquid level gauge 22, so that the second end of the drain pipe 4 is always above the liquid level of the accumulated water in the drain tank 2, further enhancing the drainage effect. Exemplarily, when the height of the drain tank 2 is set to 1m, the second end of the drain pipe 4 is located above the liquid level gauge 22, and the distance from the top of the drain tank 2 is 10cm-15cm.

[0041] Preferably, the connecting pipe 3 only serves to connect the shaft fan 1 and the drain tank 2, so that the inside of the drain tank 2 and the shaft fan 1 maintain the same negative pressure, so the diameter of the connecting pipe 3 is usually set to 6mm-10mm. Further, considering that the amount of water accumulated in the shaft fan 1 is limited, the diameter of the drain tank 2 is preferably set to 5cm-10cm.

[0042] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A shaft fan drainage device, used to drain water accumulated inside the shaft fan (1), characterized in that: include: A drain tank (2), wherein the top of the drain tank (2) is lower than the lowest point of the shaft fan (1), a drain valve (21) is provided at the bottom of the drain tank (2), and the height of the drain tank (2) satisfies h>|p| / ρg, wherein h is the height of the drain tank (2), |p| is the absolute value of the maximum negative pressure value that can be formed inside the shaft fan (1), ρ is the water density, and g is the acceleration of gravity; A connecting pipe (3), wherein a first end of the connecting pipe (3) is connected to the shaft fan (1), and a second end of the connecting pipe (3) is connected to the drain tank (2); A drainage pipe (4), wherein a first end of the drainage pipe (4) is connected to the lowest point of the axial fan (1), and a second end of the drainage pipe (4) is connected to the drain tank (2).

2. The shaft-added fan drainage device according to claim 1 is characterized in that: The first end of the connecting pipe (3) is connected to the top of the axial fan (1), and the second end of the connecting pipe (3) is connected to the top of the drain tank (2).

3. The shaft-added fan drainage device according to claim 2 is characterized in that: The connecting pipe (3) comprises a first pipe section, a second pipe section and a third pipe section, the first pipe section extending upward from the top of the shaft-added blower (1), the second pipe section connecting the first pipe section and the third pipe section, and the third pipe section extending downward to communicate with the top of the drain tank (2).

4. The shaft-added fan drainage device according to claim 3 is characterized in that The length of the first pipe section extending upward from the top of the shaft fan (1) is 5 cm-15 cm.

5. The shaft-added fan drainage device according to claim 1, characterized in that: The drain tank (2) is also provided with a liquid level meter (22).

6. The axial fan drainage device according to claim 5, characterized in that: The liquid level meter (22) is a remote liquid level meter.

7. The shaft-added fan drainage device according to claim 5, characterized in that: The drain valve (21) is a solenoid valve, and the solenoid valve is communicatively connected with the liquid level meter (22).

8. The shaft-added fan drainage device according to claim 5, characterized in that: The second end of the drainage pipe (4) is located above the liquid level meter (22).

9. The axial fan drainage device according to any one of claims 1 to 8, characterized in that: The diameter of the drain tank (2) is set to 5cm-10cm.

10. The axial fan drainage device according to any one of claims 1 to 8, characterized in that: The diameter of the connecting pipe (3) is set to 6 mm-10 mm.

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