Steam generating apparatus and exhaust structure therefor

Abstract

This utility model discloses a steam generating device and its exhaust structure, comprising: a first steam flow channel for connecting the steam generating body of the steam generating device; and a second steam flow channel connected in series downstream of the first steam flow channel; wherein a flow-limiting structure with a fixed flow area is provided between the first steam flow channel and the second steam flow channel; the flow area of ​​the flow-limiting structure is smaller than the flow area of ​​the first steam flow channel. By setting the flow-limiting structure, this utility model ensures that, under the same steam output pressure conditions, the furnace pressure of the steam generating body with the flow-limiting structure is greater than the furnace pressure without the flow-limiting structure, thereby achieving the effects of increasing furnace pressure, enhancing operational stability, improving furnace operation stability under low-pressure conditions, balancing the temperature around the furnace, and increasing steam dryness.

Description

Technical Field

[0001] This utility model relates to the field of steam generation technology, and in particular to a steam generation device and its exhaust structure that can increase furnace pressure and enhance operational stability. Background Technology

[0002] Under the national call for energy conservation and emission reduction, steam generating equipment is accelerating its development towards highly efficient, low-emission, fully premixed condensing steam generators. In particular, the inspection-free / report-free once-through gas-fired steam generators, compared to traditional steam boilers, produce steam faster, are more energy-efficient and environmentally friendly, and do not require installation, inspection, or annual boiler audits. They are widely favored by the market and are extensively used in national production and daily life, such as in hotels, restaurants, food processing, textiles, chemicals, and feed processing industries.

[0003] Steam generators are widely used in industrial production and daily life, and their core function is to heat water and convert it into steam. Traditional inspection-free steam generators, due to their limited water volume, limited number of heat exchange tubes and heat exchange area, have high heat exchange intensity. Based on research on steam generators, it has been found in actual use that traditional inspection-free steam generators are prone to problems such as frequent temperature protection errors, low steam quality, and overheating and burnout of heat exchange tubes when the combustion power is high but the furnace operating pressure is low.

[0004] Therefore, improving the operational stability of steam generating equipment under different operating conditions, enhancing steam quality, and improving the temperature uniformity around the furnace are pressing issues that need to be addressed in current steam boilers. Summary of the Invention

[0005] Through long-term on-site investigation and analysis, the inventors discovered that the malfunctions of existing once-through steam generators on the market are concentrated in the following three aspects: 1. The equipment outlet pressure is set too low, and the equipment output power is above 70%, causing frequent equipment errors; 2. The stable or instantaneous gas consumption at the terminal is too large, exceeding the rated evaporation capacity of the equipment, and the equipment cannot reach the set high pressure to operate, resulting in frequent equipment errors. For example, if 10 steam boilers can supply gas to the terminal, but only 2 are turned on and the gas consumption at the terminal is much greater than the gas production of 2 boilers, then the operating pressure of the 2 boilers will always be low, resulting in frequent water shortages, high steam superheat, and boiler temperature protection errors; 3. In the initial stage of equipment startup, the steam pipeline volume is large, and the pipeline pressure rises slowly. The steam pressure rises slowly in a short period of time, and the equipment is forced to operate under low pressure conditions and the speed of the fan and water pump is continuously increased, causing the heat exchanger to overheat and dry burn, resulting in frequent equipment errors.

[0006] The above three points can all be summarized as the boiler operating under conditions of low furnace pressure and high combustion load, that is, the input heat power per unit area (i.e., input heat flux density) exceeds the heat absorption capacity of the heat exchange tubes at the current pressure. Under the conditions of low furnace pressure and high combustion load, the input heat flux density of the furnace body exceeds the maximum allowable heat transfer heat flux density at the corresponding pressure, causing the heat exchange tube wall temperature to overheat, the liquid level to fluctuate wildly and become unstable, with fluctuations greater than ±3%; and when the steam outlet gas consumption is stable, the steam outlet pressure fluctuates wildly, with fluctuations greater than 0.2 bar; there are also fluctuations in steam temperature and steam superheat, accompanied by steam temperature and steam superheat alarms, and the furnace body temperature rises sharply, exceeding the safe operating temperature range of the heat exchange tubes, triggering the equipment safety protection alarm.

[0007] Further research revealed that for steam boilers, once the input heat flux density (CHF) of the heat exchanger tubes exceeds the limit, the steam-water phase change condition inside the tubes will transition from nucleation boiling to stable film boiling. Due to the presence of a gas film within the tube walls, the medium inside the tubes cannot absorb the heat from the high-temperature flue gas in time, leading to a sharp deterioration in heat exchange. The temperature of the heat exchanger tube walls rises rapidly, exceeding the safe operating temperature range of the heat exchanger tubes, ultimately causing the equipment to burn out. Under conditions of low furnace pressure and high combustion load, steam boilers are particularly prone to exceeding the input heat flux density limit for the heat exchanger tubes, resulting in tube burnout.

[0008] To solve the above problems, the present invention adopts the following technical solution: A steam exhaust structure for a steam generating device, comprising: A first steam flow channel for connecting the steam generating body of the steam generating equipment; A second steam channel is connected in series downstream of the first steam channel; wherein, a flow-limiting structure with a fixed flow area is provided between the first steam channel and the second steam channel; the flow area of ​​the flow-limiting structure is smaller than the flow area of ​​the first steam channel.

[0009] As one aspect of this utility model, the downstream pressure of the flow-limiting structure is the steam output pressure, and the upstream pressure is the furnace pressure; the exhaust structure is also provided with a pressure sensor for measuring the steam output pressure downstream of the flow-limiting structure.

[0010] As one aspect of this utility model, the exhaust structure includes a first pipe and a second pipe connected in series, wherein the inner cavity of the first pipe forms the first steam flow channel, the inner cavity of the second pipe forms the second steam flow channel, and the inner diameter of the second pipe is equal to the inner diameter of the first pipe.

[0011] As one aspect of this utility model, the flow-limiting structure is clamped and fixed between the first tube body and the second tube body.

[0012] As one aspect of this utility model, the downstream end of the first pipe body is provided with an outlet flange, and the upstream end of the second pipe body is provided with an inlet flange; the flow limiting structure includes a flow limiting plate that is sealed between the outlet flange and the inlet flange; the flow limiting plate has a plurality of flow holes that pass through it.

[0013] As one aspect of this utility model, the end of the second pipe is a steam output connector; the pressure sensor is connected to the second pipe.

[0014] As one aspect of this utility model, the area of ​​each flow hole is 0.78 mm². 2 ~500mm 2 The number ranges from 3 to 50.

[0015] As one aspect of this utility model, the flow passage is a round hole, a polygonal hole, or an irregularly shaped hole.

[0016] As one aspect of this utility model, the flow area of ​​the flow-limiting structure is 5% to 50% of the flow area of ​​the first steam flow channel.

[0017] A steam generator, including the exhaust structure as described above.

[0018] A steam generating device includes: a steam generating body for generating steam, which is provided with a burner and a heat exchange unit; the burner is connected to a fan; the heat exchange unit is provided with a water inlet and a steam exhaust structure; the water inlet is connected to a booster pump; The exhaust structure includes a first steam channel connected to the heat exchange unit and a second steam channel connected in series downstream of the first steam channel; a flow-limiting structure is also provided between the first steam channel and the second steam channel; the flow area of ​​the flow-limiting structure does not change with the change of steam output pressure; the flow area of ​​the flow-limiting structure is smaller than the flow area of ​​the first steam channel; the downstream pressure of the flow-limiting structure is the steam output pressure, and the upstream pressure is the furnace pressure; wherein, under the same steam output pressure conditions, the furnace pressure of the steam generator body is greater when the flow-limiting structure is provided than when the flow-limiting structure is not provided.

[0019] The beneficial effects of this utility model are as follows: 1. Increased furnace pressure and more stable operation: By setting a flow-limiting structure in the exhaust structure and making its flow area smaller than that of the first steam flow channel, the furnace pressure of the steam generator can be effectively increased under the same steam output pressure. After adding the flow-limiting structure, the minimum gas production pressure under the rated power of the equipment can be extended from 7 bar to 3 bar or even lower. This can expand the process coverage of steam in the field and improve the stability of equipment operation when the pressure drops and the load rises due to instantaneous fluctuations in gas consumption. Furthermore, higher furnace pressure means more stable steam-water phase change and stronger furnace heat exchange capacity, thereby improving the overall operational stability of the equipment.

[0020] 2. More stable furnace operation under low pressure conditions: Under low output steam pressure conditions, the presence of the flow-limiting structure helps to maintain a higher furnace pressure, avoids furnace pressure fluctuations caused by low output pressure, and ensures stable operation of the furnace under low pressure conditions. Even under high load conditions, the presence of the flow-limiting structure can increase the furnace pressure. The higher the pressure, the higher the CHF, which means it can operate under higher combustion loads.

[0021] 3. More uniform temperature around the furnace body and higher steam dryness: The higher internal pressure of the furnace body makes the residence time of steam and water in the furnace relatively longer, resulting in more complete heat exchange. This helps to make the temperature distribution around the furnace body more uniform. At the same time, more complete heat exchange and stable pressure are also conducive to producing steam with higher dryness and improving steam quality.

[0022] 4. Stable operation under normal working conditions: Under low pressure, the steam density is low, and at the same mass flow rate, the steam velocity is high. The steam pressure difference before and after the flow-limiting structure is large, and the flow-limiting and pressurizing effect is obvious, ensuring stable operation of the boiler under high pressure without overheating. Conversely, under high pressure, the steam density is high, and at the same mass flow rate, the steam velocity is low. The steam pressure difference before and after the flow-limiting structure is small, and the proportion of the pressure difference is small. Therefore, the increased power consumption of the water pump is within the allowable range. The booster pumps currently used can usually meet this requirement, and the stable operation of the boiler can be guaranteed without changing the structure.

[0023] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the present invention can be adopted. It should be understood that the scope of the embodiments of the present invention is not limited thereto.

[0024] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0025] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the steam generating equipment provided in this embodiment of the utility model.

[0028] Figure 2 yes Figure 1 A partial cross-sectional view of the exhaust structure.

[0029] Figure 3 yes Figure 1 A schematic diagram of the current limiting element.

[0030] Explanation of reference numerals in the attached figures: 100. Steam generator body; 50. Top wall of the body; 1. Exhaust structure; 2. Pressure measuring pipe; 3. Pressure sensor; 5. Water level measuring mechanism; 20. Flow restrictor; 23. Fixing clamp; 25. Flow hole; 11. Second pipe body; 12. First pipe body; 111. Second steam flow channel; 121. First steam flow channel; 112. Upstream end of the second pipe body; 122. Downstream end of the first pipe body. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0032] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] Please see Figures 1 to 3 This utility model provides a steam generating device, including: a steam generating body 100 for generating steam, which is provided with a burner and a heat exchange unit. The heat exchange unit is located inside the steam generating body; the burner is connected to a fan; the heat exchange unit is provided with a water inlet and a steam exhaust structure 1; the water inlet is connected to a booster pump.

[0035] The steam generating equipment can be a once-through steam generator. Preferably, the steam generating body 100 can refer to the content disclosed in the prior application with publication number CN114508745A entitled "New type of once-through steam generator or steam boiler and its heat exchange unit". Repeated parts will not be repeated.

[0036] The exhaust structure 1 of this embodiment is more suitable for small-capacity steam boilers. Preferably, the water volume of the steam generating equipment is less than 50L, especially for steam boilers that are exempt from inspection, where the water volume is even less than 30L. Small-capacity steam generating equipment cannot have a large heat exchange area due to the limitation of water volume, thus making its problem of low pressure and high load more prominent. Therefore, the exhaust structure 1 of this embodiment is more suitable for this application, reducing the probability of equipment damage and improving the overall operational stability of the equipment.

[0037] The exhaust structure 1 includes a first steam channel 121 connected to the heat exchange unit and a second steam channel 111 connected in series downstream of the first steam channel 121. Specifically, as shown... Figure 2As shown, the exhaust structure 1 may include a first pipe body 12 and a second pipe body 11 connected in series. Both the first pipe body 12 and the second pipe body 11 are straight pipes arranged vertically, with the second pipe body 11 fixedly connected above the first pipe body 12. The internal cavity of the first pipe body 12 forms the first steam flow channel 121, and the internal cavity of the second pipe body 11 forms the second steam flow channel 111. A connecting flange is provided at the downstream end 119 of the second pipe body 11. The upstream end 123 of the first pipe body 12 is its lower end, extending into the top wall 50 of the steam generator body 100. The upstream end 123 is a sealing end, and multiple vapor-liquid separation holes 125 are distributed on its outer wall to filter steam, increase the dryness of the output steam, and improve steam quality.

[0038] In this embodiment, a flow-limiting structure is further provided between the first steam channel 121 and the second steam channel 111. The flow area of ​​the flow-limiting structure does not change with changes in steam output pressure or furnace pressure. The flow area of ​​the flow-limiting structure is fixed. The flow area of ​​the flow-limiting structure is smaller than the flow area of ​​the first steam channel 121. Thus, when steam flows from the first steam channel 121 to the second steam channel 111, it passes through a region with a reduced cross-sectional area, thereby generating a throttling effect, reducing the steam pressure, and after passing through the flow-limiting structure, the depressurized steam is output externally.

[0039] Of course, in other embodiments, the exhaust structure is a single pipe, and the flow-limiting structure is a flow-limiting ring fixedly installed inside the pipe. The first steam flow channel and the second steam flow channel are located upstream and downstream of the internal flow-limiting ring, respectively. In this case, the first steam flow channel and the second steam flow channel are both provided by the internal cavity of the single pipe.

[0040] In this embodiment, the downstream pressure of the flow-limiting structure is the steam output pressure, and the upstream pressure is the furnace pressure. The first pipe 12 contains the furnace pressure, and the second pipe 11 contains the steam output pressure. The second steam flow channel 111 is equipped with a pressure sensor for measuring the steam output pressure. In this embodiment, as... Figure 1 and Figure 2 As shown, the steam pressure in the second steam channel 111 can be measured by connecting a pressure measuring pipe 2 to the second pipe body 11 and then connecting the pressure measuring pipe 2 to the pressure sensor 3. This pressure is the steam output pressure.

[0041] Due to the presence of the flow-limiting structure, under the same steam output pressure (i.e., the pressure within the second steam flow channel 111), the pressure inside the steam generator body 100 (i.e., upstream of the first steam flow channel 121, i.e., inside the furnace) will relatively increase due to the resistance generated by the flow-limiting structure. In other words, the furnace pressure of the steam generator body 100 with the flow-limiting structure is greater than the furnace pressure without the flow-limiting structure.

[0042] The furnace pressure can be understood as the result of the combined effect of the water pressure provided by the booster pump and the steam pressure generated by combustion. The flow-limiting structure further increases the operating pressure inside the furnace. In this embodiment, the furnace pressure can be measured by measuring the pressure inside the first steam flow channel, which is also the upstream pressure of the flow-limiting structure.

[0043] The steam generator in this embodiment operates at higher pressure and with more stable performance. The increased furnace pressure helps stabilize the combustion process, reduces pressure fluctuations, and makes the steam generator run more smoothly. The steam generator in this embodiment also exhibits more stable furnace operation under low-pressure conditions. Even under conditions requiring lower steam output pressure, the flow-limiting structure maintains a relatively high pressure inside the furnace, ensuring stable combustion and heat exchange.

[0044] In this embodiment, the steam generator exhibits a more uniform temperature around the furnace body, resulting in higher steam dryness. The higher furnace pressure slows the flow rate of the high-temperature flue gas within the furnace, allowing for longer contact time with the heat exchange unit and more thorough heat exchange. This leads to a more uniform temperature distribution throughout the furnace body, reducing localized overheating or undercooling. Sufficient heat exchange also facilitates more complete vaporization of water, increasing the dryness of the output steam.

[0045] In a preferred embodiment, when the rated output power is 20% or more, the increase in furnace pressure of the steam generator with the flow-limiting structure compared to the furnace pressure without the flow-limiting structure is 0.05 MPa or more. Alternatively, when the fan speed is 5000 rpm or more, the increase in furnace pressure of the steam generator 100 with the flow-limiting structure compared to the furnace pressure without the flow-limiting structure is 0.05 MPa or more. This indicates that the flow-limiting structure has a more significant effect on increasing furnace pressure during high-load operation, and the solution of this embodiment is more necessary to address the problems arising from low-pressure, high-load conditions.

[0046] To ensure a sufficient water supply and overcome pipeline resistance, the booster pump can be a centrifugal pump with a rated power of 1kW or higher and a rated head of 80 meters or higher, and further, a rated head of 90 meters or higher. This ensures a continuous and stable water supply to the heat exchange unit even under high furnace pressure. Of course, currently used booster pumps can usually meet this requirement, and therefore, even with the exhaust structure 1 of this embodiment, there is no need to make corresponding changes to the existing steam boiler's booster pump. This exhaust structure 1 has good adaptability to different scenarios and is easy to implement.

[0047] Continuing from the above description, the exhaust structure 1 includes a first pipe body 12 and a second pipe body 11 connected in series. The internal cavity of the first pipe body 12 forms the first steam flow channel 121, and the internal cavity of the second pipe body 11 forms the second steam flow channel 111. Preferably, the inner diameter of the second pipe body 11 and the inner diameter of the first pipe body 12 can be designed to be equal, so that the flow limiting effect is mainly achieved by the flow limiting structure itself, and the change in pipe diameter is not the main flow limiting factor, thus simplifying pipeline design and manufacturing.

[0048] Regarding the specific settings for the current limiting structure, such as Figure 2 As shown, the flow-limiting structure can be clamped and fixed between the first pipe body 12 and the second pipe body 11, which is easy to install and maintain. When the flow-limiting structure is not needed, it can be directly disassembled or replaced with a flow-limiting structure with a different flow area.

[0049] Specifically, the current-limiting structure in this embodiment uses a current-limiting plate. For example... Figure 2 , Figure 3 As shown, the downstream end 122 of the first pipe body 12 is provided with an outlet flange 128, and the upstream end 112 of the second pipe body 11 is provided with an inlet flange 118. The flow-limiting structure includes a flow-limiting plate 20 that is sealed between the outlet flange 128 and the inlet flange 118. The flow-limiting plate 20 has multiple through-holes 25 distributed on it. Steam flows from the first steam channel 121 into the second steam channel 111 through these through-holes 25. The edge of the flow-limiting plate 20 may be provided with a fixing flange 23 to facilitate positioning and sealing between the flanges.

[0050] To ensure effective flow restriction, the flow area of ​​the flow-limiting structure (i.e., the total area of ​​all flow holes 25, or the flow area of ​​the adjustable valve) is preferably 5% to 50% of the flow area of ​​the first steam flow channel 121. If the flow area of ​​the flow-limiting structure is too large, the flow restriction will be ineffective, and the problem of low-pressure, high-load operation will be poorly resolved. Conversely, if the flow area of ​​the flow-limiting structure is too small, severe pressure buildup may occur, easily exceeding the design requirements of the large pump. Specifically, to achieve more precise control over the flow restriction effect, this embodiment designs the size and number of flow holes 25. Specifically, the area of ​​each flow hole 25 can be 0.78 mm². 2 ~500mm 2 The number of these orifices ranges from 3 to 50. By adjusting the diameter and number of the flow orifices, an effective flow restriction effect can be ensured. This means that the flow restriction structure reduces the flow cross-section by at least 20%, thereby generating sufficient pressure drop or flow resistance to increase the pressure inside the furnace.

[0051] In this embodiment, the shape of the flow hole 25 is not limited. For example... Figure 3As shown, the flow passage 25 can be a round hole, a polygonal hole, or an irregularly shaped hole. Preferably, a round hole is simple to process and has relatively clear flow resistance characteristics; polygonal holes or irregularly shaped holes can be used under specific design requirements.

[0052] The steam generating equipment also includes a controller and a pressure sensor for measuring the steam output pressure. The controller is electrically connected to the pressure sensor and the blower. The controller adjusts the blower speed according to the steam output pressure, and the furnace pressure is not used as feedback pressure for the controller to adjust the blower speed. The use of a flow-limiting structure increases the furnace pressure, allowing the blower to operate stably at a higher operating speed while ensuring the heat exchange efficiency of the furnace.

[0053] Since the furnace pressure is not used as a parameter for adjusting the fan speed, the control logic of the steam generator in this embodiment is simpler. Because the control logic eliminates the use of furnace pressure as a parameter for adjusting fan speed, the complexity of the control system is significantly reduced. This not only lowers the development and maintenance costs of the control algorithm but may also improve the system's response speed and reliability. This simplified control strategy makes the system's response to steam demand more direct and efficient.

[0054] The minimum steam output pressure of the steam generator at its rated output power is below 6 bar and above 1 bar. For example, the minimum steam output pressure of the steam generator at its rated output power is below 6 bar, and further, below 5 bar. The minimum steam output pressure of the steam generator at its rated output power is below 4 bar and above 2.5 bar. By adding a flow-limiting structure to the steam generator, the minimum gas production pressure at the rated power can be extended from 7 bar to 3 bar, or even lower (1 bar). This expands the range of processes the steam can be used in on-site and improves the stability of the equipment operation when pressure drops and load increases due to instantaneous fluctuations in gas consumption.

[0055] The table below shows a detailed breakdown of the heat flux density (CHF) along the street. As can be seen, the higher the furnace pressure, the higher the CHF, allowing the steam generator to operate stably at higher speeds while maintaining heat exchange efficiency. Utilizing this principle, the flow-limiting structure in this embodiment restricts the output steam flow, creating pressure on the upstream steam, increasing the furnace pressure, and thus raising the steam CHF. This prevents overheating and burnout of the heat exchange tubes, improving the stability of the equipment operation.

[0056]

[0057] During operation of the steam generator, water enters the heat exchange unit of the steam generator body 100 via a booster pump. The heat generated by the burner heats the water to produce steam. The steam flows through the first steam channel 121, then through a flow-limiting structure (e.g., the flow-through hole 25 on the flow-limiting plate 20), enters the second steam channel 111, and is finally discharged. The pressure sensor 3 monitors the steam output pressure in the second steam channel 111 in real time via the pressure measuring pipe 2. Due to the presence of the flow-limiting structure, the pressure in the first steam channel 121 and the furnace upstream of it will be higher than the pressure in the second steam channel 111, thus achieving the beneficial effects of this invention. The water level measuring mechanism 5 is used to monitor the water level in the steam generator body 100 to ensure safe operation. The top wall 50 of the body is the upper structure of the steam generator body 100.

[0058] Table 1 below shows the comparative test results of furnace performance with and without built-in flow restrictors under the same rotational speed and steam output pressure.

[0059] Table 1. Comparison Test Results of Furnace Body Performance

[0060] The test results clearly show that adding flow restrictors at 7500 rpm and 4000 rpm can increase the average temperature of the furnace body and reduce the ambient temperature range by more than 30°C. This effectively reduces the uniformity of furnace body temperature distribution under high load, improves equipment operation stability, and also significantly improves steam dryness.

[0061] Any numerical values ​​cited herein include all values ​​ranging from a lower limit to an upper limit, increasing by one unit, with at least two units between any lower and any higher value. For example, if the quantity of a component or the value of a process variable (e.g., temperature, pressure, time, etc.) is described as being from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, the purpose is to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in this specification. For values ​​less than 1, a unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1, etc. These are merely examples intended for explicit expression, and it can be assumed that all possible combinations of values ​​listed between the minimum and maximum values ​​are explicitly described in this specification in a similar manner.

[0062] Unless otherwise stated, all ranges include the endpoints and all numbers between them. The terms "approximately" or "about" used with ranges apply to both endpoints of the range. Thus, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30," including at least the specified endpoints.

[0063] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.

[0064] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0065] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the inventors have not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A steam exhaust structure for a steam generating device, characterized in that, include: A first steam flow channel for connecting the steam generating body of the steam generating equipment; A second steam channel is connected in series downstream of the first steam channel; wherein, a flow-limiting structure with a fixed flow area is provided between the first steam channel and the second steam channel; the flow area of ​​the flow-limiting structure is smaller than the flow area of ​​the first steam channel.

2. The exhaust structure as described in claim 1, characterized in that, The downstream pressure of the flow-limiting structure is the steam output pressure, and the upstream pressure is the furnace pressure; the exhaust structure is also equipped with a pressure sensor downstream of the flow-limiting structure to measure the steam output pressure.

3. The exhaust structure as described in claim 2, characterized in that, The exhaust structure includes a first pipe and a second pipe connected in series, wherein the inner cavity of the first pipe forms the first steam flow channel, the inner cavity of the second pipe forms the second steam flow channel, and the inner diameter of the second pipe is equal to the inner diameter of the first pipe.

4. The exhaust structure as described in claim 3, characterized in that, The flow-limiting structure is clamped and fixed between the first pipe body and the second pipe body.

5. The exhaust structure as described in claim 4, characterized in that, The downstream end of the first pipe body is provided with an outlet flange, and the upstream end of the second pipe body is provided with an inlet flange; the flow limiting structure includes a flow limiting plate that is sealed between the outlet flange and the inlet flange; the flow limiting plate has a plurality of flow holes that pass through it.

6. The exhaust structure as described in claim 3, characterized in that, The end of the second pipe is a steam output connector; the pressure sensor is connected to the second pipe.

7. The exhaust structure according to claim 5, characterized by The area of ​​each flow orifice is 0.78 mm². 2 ~500mm 2 The number ranges from 3 to 50.

8. The exhaust structure as described in claim 7, characterized in that, The flow passage can be a round hole, a polygonal hole, or an irregularly shaped hole.

9. The exhaust structure as described in claim 1, characterized in that, The flow area of ​​the flow-limiting structure is 5% to 50% of the flow area of ​​the first steam channel.

10. A steam generating apparatus characterized by comprising: Includes the exhaust structure as described in any one of claims 1-9.

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