Leak detection and water seal apparatus and method for boiler drain recovery condenser valve

Abstract

The present application relates to a kind of for boiler drainage recovery condenser valve leak detection and water seal device and method, device is installed on the water drain pipe after the drainage recovery condenser stop valve, including water injection pipeline, which is in the form of bypass access drainage recovery condenser stop valve after water drain pipe, water injection pipeline is equipped with leak detection pressure gauge and leak detection isolation door, and is connected vacuum pump water supply opening.Drainage recovery condenser stop valve after water drain pipe is equipped with boiler drainage to condenser control valve before stop valve water drain isolation door, and one end of drainage recovery condenser stop valve after water drain pipe is connected drainage recovery condenser pipeline, the other end is open structure.Compared with prior art, the present application has reliable and stable, easy to maintain, little influence on system, good sealing performance, easy to check and other advantages.

Description

Technical Field

[0001] This invention relates to the field of boiler start-up condensate recovery systems, and in particular to a leak detection and water sealing device and method for condenser valves used in boiler condensate recovery systems. Background Technology

[0002] like Figure 1 As shown, currently, in the initial startup phase of ultra-supercritical tower once-through boilers, to ensure the safety of the water-cooled walls and prevent heat transfer deterioration, the startup flow rate is determined based on the structure and form of the water-cooled walls, generally 25% to 40% of the rated feedwater flow rate. During the cold-state cleaning phase of boiler startup, the boiler water after the separator flows sequentially through the water storage tank, atmospheric expansion tank, and boiler condensate tank, and is either recovered to the condensate recovery pump or directly discharged to the unit drainage trough. After boiler ignition, the boiler operates in a wet state during the initial startup phase, with a steam-liquid mixture at the vertical water-cooled wall outlet. The steam and water are separated by the separator, and the boiler water returns to the inlet of the primary economizer via the water storage tank and the boiler water circulation pump. The water level in the storage tank is controlled by a water level control valve, and excess condensate is recovered to the condensate via the condensate recovery pump.

[0003] During normal unit operation, the valves related to the boiler condensate recovery condenser are in the closed state. Since the relevant shut-off valves of the condensate recovery condenser are driven by motors, in order to prevent the motor from being over-torque protected when the valves are opened and closed, a margin is left in the valve opening and closing stroke. In addition, the normal wear and tear of the valves leads to poor sealing of the shut-off valves. In actual production, it has also been found that there is backflow of air at the exhaust port after the exhaust valve of the condensate recovery pump outlet pipe is opened, which causes air leakage in the condenser and affects the efficiency of the unit.

[0004] like Figure 2 As shown, in the existing scheme, hose 4 is directly connected to the outlet of the drain valve 1 of the existing boiler drain to condenser regulating valve, and then connected to the drain valve 5 of the unit's demineralized water makeup water header. The water source used is the drain port of the unit's demineralized water makeup water header. The connection between the hose and each outlet uses clamps, which is an unreliable fixing method. The opening of the drain valve of the makeup water header needs to be adjusted to control the water seal pressure. The unit's demineralized water pressure is controlled by the chemical makeup water pump, and the pressure is affected by the amount of makeup water. The hose is prone to detachment, and the makeup water will flow out into the turbine hall, affecting the operational safety of nearby equipment. Moreover, in the original scheme, the drain valve of the drain to condenser pipeline needs to be opened to use the water seal device. Once the hose detaches at the drain port, it will create a leak point, which will seriously affect the vacuum of the unit's condenser and operational safety. Operators need to check the hose connection regularly to ensure it is secure. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of the prior art and provide a reliable, stable, easy-to-maintain, well-sealed, and easy-to-inspect leak detection and water sealing device and method for boiler condenser valves that recover condensate.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A leak detection and water seal device for a boiler condensate recovery condenser valve is installed on the drain pipe after the condensate recovery condenser shut-off valve. The device includes a water injection pipe that is connected to the drain pipe after the condensate recovery condenser shut-off valve in the form of a bypass. The water injection pipe is equipped with a leak detection pressure gauge and a leak detection isolation valve, and is connected to the vacuum pump water inlet.

[0008] Furthermore, the drain pipe after the condensate recovery condenser shut-off valve is equipped with a boiler drain to condenser regulating valve shut-off valve drain isolation valve. One end of the drain pipe after the condensate recovery condenser shut-off valve is connected to the condensate recovery condenser pipeline, and the other end is an open structure.

[0009] Furthermore, the water injection pipeline is connected to the drain pipe after the drain valve of the condensate recovery condenser, and the pipeline between the boiler drain water to the drain isolation valve of the condenser regulating valve and the drain valve recovery condenser pipeline.

[0010] Furthermore, the condensate recovery condenser pipeline is divided into a high-pressure condenser connection branch and a low-pressure condenser connection branch; there are two drain pipes and two injection pipes after the condensate recovery condenser shut-off valve, which are respectively connected to the high-pressure condenser connection branch and the low-pressure condenser connection branch, and the two injection pipes are connected to the vacuum pump water inlet.

[0011] Furthermore, the water injection pipeline is a pipe.

[0012] The present invention also provides a leak detection and water seal method for a boiler condenser valve for drain recovery, as described above, comprising the following steps:

[0013] When the cold vacuum of the boiler start-up condensate recovery system has not been established, water is injected into the pipeline between the shut-off valves before and after the boiler condensate recovery condenser control valve by opening the leak detection isolation valve, through the water injection pipeline and the water discharge pipeline after the condensate recovery condenser shut-off valve, and the leak detection pressure gauge is used to check whether there is internal leakage in the shut-off valves before and after the boiler condensate recovery condenser control valve.

[0014] Furthermore, the method also includes: during the process of increasing the vacuum, judging the wear of the sealing surfaces of the shut-off valves before and after the boiler condensate recovery condenser valve by the change in the reading of the leak test pressure gauge.

[0015] Furthermore, the method also includes: when it is determined that there is internal leakage in the shut-off valves before and after the boiler condensate recovery condenser regulating valve, the water seal pressure is increased by adjusting the opening of the leak detection isolation valve.

[0016] Furthermore, during the process of adjusting the opening of the leak detection isolation door, the pressure is ensured to be above 0 kPa by using a leak detection pressure gauge.

[0017] Furthermore, the drain pipe after the condensate recovery condenser shut-off valve is provided with a drain isolation valve for the boiler drain to condenser regulating valve. The method also includes: when the boiler starts the drain recovery system and needs to drain water, the water is drained by opening the drain isolation valve for the boiler drain to condenser regulating valve.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] This invention adds a water injection line as a bypass to the drain pipe after the shut-off valve of the condensate recovery condenser, without affecting the normal drain function of the system. The water injection line is directly connected to the vacuum pump for water supply, with the water source taken from the condensate pump outlet, ensuring stable pressure. A leak detection valve is also installed for easy operation. A leak detection pressure gauge is installed on the water injection line to monitor changes in water seal pressure in real time, enabling leak detection. Overall, this invention has the following advantages:

[0020] (1) Reliable and stable: The water source pressure of the water seal is stable, which can meet the requirements of leak detection and water seal of the stop valve.

[0021] (2) Easy to maintain: The hose does not need to be removed during maintenance of the drainage recovery system and water replenishment system pipelines, and does not occupy the system's own water discharge point.

[0022] (3) Minimal impact on the system: The water source is taken from the vacuum pump makeup water, and the upstream water source is the condensate user's main pipe. The water quality of the source water is guaranteed and will not pollute the condensate. In addition, the unit's makeup water volume will not increase when there is leakage in the shut-off valve.

[0023] (4) Good sealing performance: When the gate leaks, the leak detection gate can adjust the water injection flow rate and the water source pressure meets the sealing requirements.

[0024] (5) Easy to inspect: The added leak test pressure gauge can check the effect of the water seal in real time, providing a basis for the maintenance of the shut-off valve, and verifying the effect of the water seal in combination with the vacuum tightness test. After using the water seal, the vacuum tightness of the unit under the same working conditions is improved by 30 to 50 Pa. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a boiler start-up condensate recovery system provided in the background art of the present invention;

[0026] Figure 2This invention provides a schematic diagram of a water seal device for valves related to boiler start-up condensate recovery condenser in the background art.

[0027] Figure 3 This is a schematic diagram of a leak detection and water seal device for a boiler condenser valve used for condensate recovery, provided in an embodiment of the present invention.

[0028] In the diagram, 1. Boiler drain to condenser regulating valve shut-off valve, 2. Leak test pressure gauge, 3. Leak test valve, 4. Hose, 5. Unit demineralized water makeup water header drain valve. Detailed Implementation

[0029] 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, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed during use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] Example 1

[0034] like Figure 3As shown, this embodiment provides a leak detection and water seal device for a boiler condensate recovery condenser valve. It is installed on the drain pipe after the condensate recovery condenser shut-off valve and includes a water injection pipe. The water injection pipe is connected to the drain pipe after the condensate recovery condenser shut-off valve in the form of a bypass. The water injection pipe is equipped with a leak detection pressure gauge 2 and a leak detection isolation valve 3, and is connected to the vacuum pump water inlet.

[0035] The water injection pipeline is a pipe. This solution directly connects the pipe to the vacuum pump for water replenishment. The water source is taken from the outlet of the condensate pump, the pressure is stable, and a leak detection valve is installed for easy operation.

[0036] The original solution could only achieve water sealing, but the hose lacked a pressure gauge, making leak detection impossible. The improved solution adds a leak-detection pressure gauge 2, which can monitor changes in water seal pressure in real time, thus enabling leak detection.

[0037] Specifically, the drain pipe after the condensate recovery condenser shut-off valve is equipped with a boiler drain to condenser regulating valve shut-off valve drain isolation valve 1. One end of the drain pipe after the condensate recovery condenser shut-off valve is connected to the condensate recovery condenser pipeline, and the other end is an open structure.

[0038] The original solution involved connecting the drain outlet of the drainage system and the water supply system with a flexible hose. When the system needed to be drained for maintenance, the hose had to be removed first, which increased the workload of system isolation and restoration. This solution adds a water supply line in the form of a bypass, which does not affect the normal water discharge of the system.

[0039] The water injection pipeline connects to the drain pipeline after the condensate recovery condenser shut-off valve, and the boiler drains water into the pipeline between the condenser regulating valve shut-off valve drain isolation valve 1 and the condensate recovery condenser pipeline.

[0040] In this embodiment, the condensate recovery condenser pipeline is divided into a high-pressure condenser connection branch and a low-pressure condenser connection branch; there are two water discharge pipes and two water injection pipes after the condensate recovery condenser shut-off valve, which are respectively connected to the high-pressure condenser connection branch and the low-pressure condenser connection branch, and the two water injection pipes are connected to the vacuum pump water inlet.

[0041] This embodiment also provides the above-mentioned leak detection and water seal method for the valve of the boiler condensate recovery condenser, including the following steps:

[0042] When the cold vacuum of the boiler start-up condensate recovery system is not established, water is injected into the pipeline between the shut-off valves before and after the boiler condensate recovery condenser regulating valve by opening the leak detection isolation valve 3, through the water injection pipeline and the water discharge pipeline after the shut-off valve of the condensate recovery condenser, and the leak detection pressure gauge 2 is used to check whether there is internal leakage in the shut-off valves before and after the boiler condensate recovery condenser regulating valve.

[0043] During the process of increasing the vacuum, the wear of the sealing surfaces of the shut-off valves before and after the boiler condensate recovery condenser is determined by the change in the reading of the leak test pressure gauge 2.

[0044] When it is determined that there is internal leakage in the shut-off valves before and after the boiler condensate recovery condenser regulating valve, the water seal pressure is increased by adjusting the opening of the leak detection isolation valve 3.

[0045] Specifically, during the process of adjusting the opening of the leak detection isolation door 3, the pressure is ensured to be above 0 kPa by using the leak detection pressure gauge 2.

[0046] The drain pipe after the condensate recovery condenser shut-off valve is equipped with a drain isolation valve 1 for the boiler drain to condenser regulating valve. The method also includes: when the boiler starts the drain recovery system and needs to drain water, the drain is discharged by opening the drain isolation valve 1 for the boiler drain to condenser regulating valve.

[0047] The following is a specific implementation process of the above solution:

[0048] This leak detection device utilizes the existing drain pipe after the shut-off valve of the condensate recovery condenser, and adds a water injection pipeline, corresponding valves, and a leak detection pressure gauge. It can perform cold-state leak detection during unit shutdown and water injection sealing during operation. Since the condenser vacuum is above 95 kPa during normal operation, even a slight decrease in the tightness of the valves related to the condensate recovery condenser can lead to air leakage and a reduction in vacuum.

[0049] During operation, before the unit's cold vacuum is established, water is injected into the pipeline between the shut-off valves before and after the boiler condensate recovery condenser regulating valve by opening the leak detection isolation valve 3. The shut-off valve is then checked for internal leakage using the leak detection pressure gauge 2, allowing the valve's tightness to be determined without disassembling it. During the unit's vacuum increase process, the changes in the leak detection pressure gauge 2 reading can be monitored in real time to track the wear of the shut-off valve's sealing surface. Even in the event of internal leakage, the water seal pressure can be increased by adjusting the opening of the leak detection isolation valve 3. The condensate pump outlet pressure is typically between 2.5 and 4 MPa, and the vacuum pump makeup water pressure can be stabilized at 1 MPa after pipeline throttling. Even if the shut-off valve leaks internally, adjusting the leak detection isolation valve 3 to ensure the leak detection pressure gauge pressure is above 0 kPa will ensure water seal stability and prevent air from entering the condenser.

[0050] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A leak detection and water seal device for a boiler condensate recovery condenser valve, wherein the device is installed on the drain pipe after the condensate recovery condenser shut-off valve, including a water injection pipe, which is connected to the drain pipe after the condensate recovery condenser shut-off valve in the form of a bypass, and the water injection pipe is provided with a leak detection pressure gauge (2) and a leak detection isolation valve (3), and is connected to the vacuum pump water inlet; The drain pipe after the condenser shut-off valve of the condenser is provided with a boiler drain to condenser regulating valve drain isolation valve (1). One end of the drain pipe after the condenser shut-off valve is connected to the condenser pipeline, and the other end is an open structure. The water injection pipeline is connected to the drain pipeline after the drain valve of the condenser drain recovery condenser. Boiler drain water is discharged into the pipeline between the drain isolation valve (1) of the condenser regulating valve and the drain recovery condenser pipeline. Its features are, The method includes the following steps: When the cold vacuum of the boiler start-up condensate recovery system is not established, water is injected into the pipeline between the shut-off valves before and after the boiler condensate recovery condenser regulating valve by opening the leak detection isolation valve (3), through the water injection pipeline and the water discharge pipeline after the shut-off valve of the condensate recovery condenser, and the leak detection pressure gauge (2) is used to check whether there is internal leakage in the shut-off valves before and after the boiler condensate recovery condenser regulating valve. The method also includes: during the process of increasing the vacuum, judging the wear of the sealing surfaces of the shut-off valves before and after the boiler condensate recovery condenser by the change in the reading of the leak test pressure gauge (2); The method further includes: when it is determined that there is internal leakage in the shut-off valves before and after the boiler condensate recovery condenser regulating valve, the water seal pressure is increased by adjusting the opening of the leak detection isolation valve (3); During the process of adjusting the opening of the adjustment and leak detection isolation door (3), the pressure is ensured to be above 0 kPa by the leak detection pressure gauge (2).

2. The method according to claim 1, characterized in that, The condensate recovery condenser pipeline is divided into a high-pressure condenser connection branch and a low-pressure condenser connection branch; there are two water discharge pipes and two water injection pipes after the condensate recovery condenser shut-off valve, which are respectively connected to the high-pressure condenser connection branch and the low-pressure condenser connection branch. The two water injection pipes are connected to each other and then connected to the vacuum pump water inlet.

3. The method according to claim 1, characterized in that, The method further includes: when the boiler starts up the condensate recovery system and needs to release water, the water is released by opening the boiler condensate to condenser regulating valve before the shut-off valve (1).

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