Water supply device and boiler

Abstract

To provide a water supply device which can measure a water supply amount in a wide range at low cost.SOLUTION: Water supply devices (5, 10) for supplying water to an apparatus includes: a first water supply passage (61); a first flow rate measuring instrument (FM1) for measuring a water supply amount in the first water supply passage; a second water supply passage (62) different from the first water supply passage (61); a second flow rate measuring instrument (FM2) for measuring a water supply flow rate in the second water supply passage (62); and an opening / closing valve (53) for opening / closing the second water supply passage (62). When the apparatus is in a first state, water is supplied from the first water supply passage (61) to the apparatus with the opening / closing valve (53) in a closed state, and when the apparatus is in a second state, water is supplied from the first water supply passage (61) and the second water supply passage (62) to the apparatus with the opening / closing valve (53) in an open state. Even when the apparatus is in the first state, when a predetermined condition is established, water is supplied from the first water supply passage (61) and the second water supply passage (62) with the opening / closing valve (53) in the open state.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a water supply device and a boiler. [Background technology]

[0002] In a water supply system device for supplying water to water-using equipment such as a boiler, there is a device that determines the amount of water supplied to the equipment based on a pulse signal transmitted from a water supply flow meter installed in the water supply line (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP2015-090252A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, when controlling feedwater in a boiler with a high turndown ratio, the difference in feedwater flow rate is large between high and low combustion states. Also, when the water level in the boiler body (boiler body) becomes too low, backup feedwater control is performed to rapidly raise the water level in the boiler body to prevent overheating, and in this case it is necessary to rapidly increase the feedwater flow rate.

[0005] Therefore, the range of the water supply amount is wide, from the amount of water supply corresponding to the low combustion state to the amount of water supply that requires a large amount of water, such as in the high combustion state or backup water supply. Therefore, the flow meter installed in the water supply line must be able to measure a wide range. However, flow meters that can accurately measure such a wide range are expensive, and some manufacturers do not manufacture them, so they may be difficult to obtain.

[0006] The present invention was devised in consideration of the above-mentioned situation, and its object is to provide a water supply device that can measure a wide range of water supply amounts without requiring a flow meter that can measure a wide range with high accuracy. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, a water supply device according to one aspect of the present invention is a water supply device that supplies water to an equipment, and is equipped with a first water supply passage, a first flow rate meter that measures the water supply amount of the first water supply passage, a second water supply passage different from the first water supply passage, a second flow rate meter that measures the water supply flow rate of the second water supply passage, and an on-off valve that opens and closes the second water supply passage, and when the equipment is in a first state, the on-off valve is closed and water is supplied to the equipment from the first water supply passage, and when the equipment is in a second state, the on-off valve is open and water is supplied to the equipment from the first water supply passage and the second water supply passage, and even when the equipment is in the first state, when a predetermined condition is satisfied, the on-off valve is opened and water is supplied from the first water supply passage and the second water supply passage.

[0008] According to the above configuration, when the device is in the first state, the feed water flow rate is measured by the first flow rate measuring device, and when the device is in the second state or even when the device is in the first state, water is also supplied from the second water supply passage when a predetermined condition is met, and the feed water flow rate can be measured by each of the first flow rate measuring device and the second flow rate measuring device. This makes it possible to measure the range of feed water flow rates from the first state to the second state using multiple flow rate measuring devices without requiring an expensive flow rate measuring device that can measure with high accuracy, and makes it possible to measure a wide range of feed water flow rates without increasing costs.

[0009] Preferably, the amount of water supplied from the second water supply passage is greater than the amount of water supplied from the first water supply passage.

[0010] According to the above configuration, it is easy to use the water supply device to supply water to a device that is designed to have a larger range between the upper and lower limits of the water supply flow rate.

[0011] Preferably, the first water supply passage is provided with a flow rate regulating valve for regulating the amount of water supplied to the first water supply passage.

[0012] According to the above configuration, the water supply flow rate from the first water supply passage to the equipment can be adjusted, so the lower limit can be made smaller, making it easier to use for supplying water to equipment that is expected to have a larger range between the upper and lower limits of the water supply flow rate.

[0013] Preferably, the equipment is a boiler equipped with the water supply device, the second state is a state in which the amount of combustion is greater than that in the first state, and the specified condition includes a condition that is met when it is detected that the water level inside the boiler is lower than a predetermined low water level.

[0014] According to the above configuration, even when the combustion amount is low, when the water level inside the boiler body does not reach a predetermined low water level, water can be supplied from the first water supply passage and the second water supply passage, and the water supply flow rate at that time can be measured by each of the first flow measuring device and the second flow measuring device. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram for explaining the schematic configuration of a boiler equipped with a water supply device. [Diagram 2] 10 is a flowchart for explaining an example of a water supply-related process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] <Overview of the configuration> Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, in this embodiment, a schematic configuration of a boiler 1, which is an example of equipment, will be described with reference to FIG. 1. As shown in FIG. 1, the boiler 1 includes a boiler body (boiler body) 2 that burns fuel to generate steam, a blower 3 that sends air into the boiler body 2 through an air supply passage 30, a flue 4 that guides exhaust gas and the like from the boiler body 2, a fuel supply line (not shown) that supplies fuel to the boiler body 2, a water supply system 5 that supplies water to the boiler body 2, and a control device 10 that controls the operation of the boiler 1 including the water supply system 5. An example in which the fuel is oil will be described, but the fuel is not limited to a liquid such as oil, and may be a gas such as gas.

[0017] The fuel supply line is provided with a fuel regulating valve that functions as a pressure regulating valve capable of adjusting the flow rate of fuel supplied to the boiler body 2 and also has a shutoff function. The fuel regulating valve is, for example, a motor valve, but is not limited to a motor valve and may be an air-controlled valve as long as it adjusts the flow rate of fuel. The fuel supplied from the fuel supply line is supplied to a burner in the boiler body 2 and is mixed with the combustion air blown from the blower 3 for combustion. The flow rate of the combustion air is adjusted by the opening degree of a damper provided in the air supply path, or alternatively or in addition to this, by using an inverter to adjust the rotation speed (frequency) of the fan of the blower 3.

[0018] The boiler 1 generates steam by burning fuel with a burner in the boiler body 2 to heat and boil boiler water. The boiler body 2 is formed in a substantially cylindrical shape and includes a burner, water pipes, an upper header, and a lower header. The lower header is provided at the bottom of the boiler body 2 and is connected to the lower parts of the multiple water pipes. The lower header is connected to a water supply line 6. The water supply line 6 is provided with a water supply pump 60 and a check valve (not shown). Water is supplied from the water supply pump 60 to the lower header via the water supply line 6, and the supplied water is heated in the water pipes. The upper header is provided at the top of the boiler body 2 and is connected to the upper parts of the multiple water pipes. The generated steam is collected in the upper header and taken out from a steam pipe.

[0019] The control device 10 is realized by a computer including a memory, a timer, and an arithmetic processing unit, and controls the operation and operation of the boiler 1, for example, controlling the operation at the time of ignition and shutdown, a plurality of types of combustion states with different combustion amounts depending on the steam load (for example, low combustion state, medium combustion state, high combustion state, etc.), the operation of the feedwater pump 60 and the on-off valve 53 in the feedwater passage 6 (feedwater control) described later. The control device 10 is electrically connected to the blower 3, the fuel adjustment valve, and the devices of the feedwater system 5 (feedwater flow meters FM1 and FM2, on-off valve 53, feedwater pump 60, etc. described later). In the boiler in this embodiment, water is supplied from the feedwater passage 6 to the inside of the boiler body 2 (one example of equipment) according to the generated steam (evaporation amount). It is not limited to the case of a boiler that controls one of a plurality of types of combustion states with different combustion amounts in stages, but may be a so-called proportional control boiler that can finely control the combustion amount.

[0020] The feedwater system 5 includes various devices, piping, etc., which are provided on the feedwater passage 6 and are required to supply water to the boiler body 2. The feedwater passage 6 branches into a first feedwater passage 61 and a second feedwater passage 62 downstream of the feedwater pump 60. The first feedwater passage 61 is provided with a feedwater flow meter FM1 (first flow rate measuring device). The second feedwater passage 62 is provided with a feedwater flow meter FM2 (second flow rate measuring device) and an on-off valve 53 that opens and closes the flow path of the second feedwater passage 62. Although the on-off valve 53 is illustrated as being downstream of the feedwater flow meter FM2, the on-off valve 53 may be provided upstream of the feedwater flow meter FM2 as long as it is on the second feedwater passage 62.

[0021] Feedwater flow meter FM1 and feedwater flow meter FM2 measure the feedwater flow rate flowing through the feedwater passages (first feedwater passage 61 and second feedwater passage 62) in which they are respectively provided, and transmit, for example, a pulse signal to control device 10. Control device 10 can measure the amount of feedwater to boiler body 2 based on the pulse signals transmitted from feedwater flow meter FM1 and feedwater flow meter FM2. Note that, if there is only one pulse signal input port, the pulse signals from each flow meter are added together and input and output at one point. In addition, the flow rate range that can be measured by feedwater flow meter FM1 and feedwater flow meter FM2 (proper use flow rate range m 3 / h) are different.

[0022] Here, in the case of a boiler with a high turndown ratio that performs control in which the combustion state is switched over a wide range in multiple stages (e.g., proportional control, four-position control, etc.), it is desirable that the range of the amount of feedwater supplied to the boiler body can also be adapted to a wide range according to the combustion state. In addition, in order to respond to sudden load fluctuations and the need to cool the boiler body (boiler body), it is desirable to be able to adjust the feedwater flow rate over a wider range than the turndown ratio. However, many feedwater flow meters that can accurately measure a wide range of flow rates (a wide range from the lower limit to the upper limit of the appropriate use flow rate range) with a single device are expensive, in short supply, and may be difficult to obtain.

[0023] Therefore, in this embodiment, the water supply system is branched into two systems, and a water supply flow meter FM1 (for example, 0.14 to 2.8 m) capable of measuring low water volumes is provided. 3 / h) and the feedwater flow meter FM2, which can measure high water volumes (e.g., 0.29 to 6 m 3 / h) is combined to measure the feedwater flow rate. Therefore, even if water is fed in accordance with a wide range of combustion conditions of the boiler 1, the feedwater flow rate can be measured using a low-cost, highly accurate feedwater flow meter by combining feedwater flow meters with different measurable flow rate ranges. This makes it possible to maintain high accuracy in measuring the feedwater flow rate even if the range of fluctuation in the feedwater flow rate becomes large.

[0024] For example, the feedwater flow meter FM1 can properly measure a flow rate lower than the lower limit of the flow rate range that the feedwater flow meter FM2 can measure, while the feedwater flow meter FM2 can properly measure a flow rate higher than the upper limit of the flow rate range that the feedwater flow meter FM1 can measure.

[0025] In addition, in this embodiment, the amount of water supplied to equipment such as the boiler 1 is greater from the second water supply passage 62, which is provided with a water supply flow meter FM2 capable of measuring a high water volume, than from the first water supply passage 61, which is provided with a water supply flow meter FM1 capable of measuring a low water volume.

[0026] Therefore, in a low combustion state where it is expected in advance that the amount of water supplied to the boiler body 2 will be small, the control device 10 closes the on-off valve 53 provided in the second feedwater passage 62. As a result, water is supplied to the boiler body 2 from the first feedwater passage 61 provided with the feedwater flow meter FM1 capable of measuring a low water amount. Therefore, for example, if water is supplied from the second feedwater passage 62, when the amount of water supplied falls below the lower limit of the flow rate range measurable by the feedwater flow meter FM2, there is a risk that the feedwater flow meter FM2 will determine the flow rate as 0 due to the low cut. However, since the feedwater amount is measured by the feedwater flow meter FM1 capable of measuring a low water amount, the flow rate measurement accuracy can be maintained at a high level.

[0027] On the other hand, in a high combustion state (when the combustion load is high (e.g., load rate of 50% or more)), or when a specified condition is satisfied, the amount of feedwater needs to be increased. When a specified condition is satisfied, for example, even in a low combustion state, when the water level in the boiler body 2 has dropped too much or the temperature in the boiler body 2 has risen too much, it is necessary to perform backup water feed control to prevent overheating of the boiler body 2. For example, when the electrode rod detecting the water level in the boiler body 2 no longer detects a predetermined water level (a low water level that is an overheat prevention water level), it is determined that the water level in the boiler body 2 has fallen below the overheat prevention water level, or when a temperature higher than a predetermined temperature is detected in the boiler body 2.

[0028] In a high combustion state or when back-up water is supplied to prevent overheating, the amount of water required is greater than the upper limit flow rate that can be measured by the feedwater flow meter FM1, which measures a low water amount. Therefore, in a high combustion state or when back-up water is supplied to prevent overheating, the control device 10 opens the on-off valve 53 and allows water to flow also from the second feedwater passage 62 so that water can be supplied to the boiler body 2. As a result, even if the amount of water supplied to the boiler body 2 increases, the feedwater flow rate can be measured not only by the feedwater flow meter FM1 but also by the feedwater flow meter FM2, which can measure a high water amount, so that high measurement accuracy can be maintained.

[0029] In this embodiment, the predetermined flag is set to ON when the amount of feedwater increases, such as when the low combustion state is shifted to the high combustion state, or when a predetermined condition that requires backup water feed control is satisfied. On the other hand, the predetermined flag is set to OFF when the high combustion state is shifted to the low combustion state, or when backup water feed control is no longer required and the predetermined condition is released. Examples of when backup water feed control is no longer required include when a predetermined time (e.g., a time estimated to be able to stably maintain a water level higher than the overheat prevention water level) has elapsed since the water level in the boiler body 2 became higher than the overheat prevention water level due to water being supplied, or when the temperature in the boiler body 2 falls below a predetermined temperature.

[0030] In this embodiment, when the predetermined flag is set to ON, the amount of water supplied to the boiler body 2 is large, and therefore the feedwater flow rate to the boiler body 2 is determined based on the pulse signals transmitted from the feedwater flow meters FM1 and FM2. On the other hand, when the predetermined flag is set to OFF, the amount of water supplied to the boiler body 2 is small, and therefore the feedwater flow rate to the boiler body 2 is determined based on the pulse signal transmitted from the feedwater flow meter FM1.

[0031] <Water supply-related treatment> 2 is a flow chart for explaining an example of the water supply-related process. The control device 10 starts the water supply-related process at regular intervals (for example, every second), and executes the water supply-related process once started until it is terminated.

[0032] In step S01, it is determined whether a predetermined condition is satisfied or whether the engine is transitioning from a low combustion state to a high combustion state. When it is determined in step S01 that the predetermined condition is satisfied or the engine is transitioning from a low combustion state to a high combustion state, a predetermined flag is set to ON in step S02, and the on-off valve 53 is controlled to be in an open state.

[0033] After the on-off valve 53 is controlled to the open state in step S02, the process proceeds to step S03. On the other hand, when it is not determined in step S01 that the predetermined condition is satisfied or that the low combustion state is being shifted to the high combustion state, the process proceeds to step S03.

[0034] In step S03, it is determined whether the predetermined condition has been released or whether the state has transitioned from the high combustion state to the low combustion state. The predetermined condition is released when, for example, a predetermined time has elapsed since the water level in the boiler body 2 became higher than a predetermined water level (superheat prevention water level) that has been determined in advance. When it is determined in step S03 that the predetermined condition has been released or the state has transitioned from the high combustion state to the low combustion state, the process proceeds to step S04, where a predetermined flag is set to OFF and the on-off valve 53 is controlled to be in a closed state.

[0035] After the on-off valve 53 is controlled to the closed state in step S04, the process proceeds to step S05. On the other hand, if it is not determined in step S03 that the predetermined condition has been released or that the high combustion state is being shifted to the low combustion state, the process proceeds to step S05.

[0036] In step S05, it is determined whether a predetermined flag is set to ON. The predetermined flag is a flag set in step S02. When it is determined that the predetermined flag is set to ON, in step S06, the feedwater flow rate is determined based on the pulse signals from the feedwater flow meter FM1 provided in the first feedwater passage 61 and the feedwater flow meter FM2 provided in the second feedwater passage 62, and the process is terminated. When a predetermined condition is satisfied or when the low combustion state is shifted to the high combustion state, a large amount of water is required, so that the on-off valve 53 is opened to allow water to flow into the second feedwater passage 62, which has a larger amount of water than the first feedwater passage 61. In addition, when the on-off valve 53 is opened, the predetermined flag is turned ON, and in addition to the pulse signal from the feedwater flow meter FM1, the pulse signal from the feedwater flow meter FM2 is also used to determine the feedwater flow rate. As a result, even if the feedwater flow rate to the boiler body 2 increases, the flow rate can be properly measured by the feedwater flow meter FM2, which can measure a high water amount in addition to the feedwater flow meter FM1.

[0037] On the other hand, if it is not determined in step S05 that the predetermined flag is set to ON, the feedwater flow rate is identified based on the pulse signal from the feedwater flow meter FM1 provided in the first feedwater passage 61 in step S07, and the process ends. In step S04, the predetermined flag is turned OFF when the feedwater flow rate decreases, such as when the predetermined condition is released or when the high combustion state is shifted to a low combustion state, and the pulse signal from the feedwater flow meter FM1 is used to identify the feedwater flow rate, and the pulse signal from the feedwater flow meter FM2 is not used. In addition, by closing the on-off valve 53, water is supplied from the first supply passage 61. As a result, the feedwater flow meter FM1, which is capable of measuring a low water flow rate, can also properly measure the flow rate at a low water flow rate.

[0038] As described above, the feedwater system (feedwater system 5 and control device 10) of the present invention according to the above embodiment measures the feedwater flow rate with the feedwater flow meter FM1 (first flow rate measuring device) when equipment such as the boiler 1 is in a low combustion state (first state), and when equipment such as the boiler 1 is in a high combustion state (second state) or when a backup water supply is made to supply a high amount of water in a low combustion state due to the establishment of a predetermined condition, water is also supplied from the second feedwater passage 62 and the feedwater flow rate can be measured with the feedwater flow meter FM1 and the feedwater flow meter FM2. This allows measurement with multiple flow rate measuring devices (feedwater flow meters) without requiring an expensive flow rate measuring device that can accurately measure the range of feedwater flow rates from when the low combustion state is in effect to when a high amount of water is required to be supplied, such as when the high combustion state is in effect or when backup water supply is in effect, and thus makes it possible to measure a wide range of feedwater flow rates without increasing costs.

[0039] 2 includes a condition that is established when, even in a low combustion state, the electrode rod detecting the water level in the boiler body 2 no longer detects a predetermined water level (detects that the water level is below the predetermined water level), and backup water supply control must be performed to prevent overheating of the boiler body 2. As a result, even when the combustion amount is low, when the water level in the boiler body 2 does not reach the predetermined low water level, water can be supplied from the first water supply passage 61 and the second water supply passage 62, and the feedwater flow rate at that time can be measured by the feedwater flow meter FM1 and the feedwater flow meter FM2, respectively.

[0040] In this embodiment, the amount of feedwater supplied from each feedwater passage to equipment such as the boiler 1 is greater in the second feedwater passage 62 provided with the feedwater flow meter FM2 capable of measuring a high water flow rate than in the first feedwater passage 61 provided with the feedwater flow meter FM1 capable of measuring a low water flow rate. This makes it easier to use the second feedwater passage 62 to supply water to equipment such as the boiler 1, which is intended to have a larger range between the upper and lower limits of the feedwater flow rate.

[0041] The present invention is not limited to the above-described embodiment, and various modifications and applications are possible. Modifications of the above-described embodiment that can be applied to the present invention will be described below.

[0042] In the above embodiment, an example in which an on-off valve or the like is not provided in the first water supply passage 61 has been described. However, the present invention is not limited to this, and the first water supply passage 61 may be provided with a flow rate control valve capable of adjusting the flow rate by adjusting the opening degree, for example. This allows the amount of feedwater supplied from the first water supply passage 61 to be further reduced, making it possible to improve the turndown ratio of the boiler. Since the opening degree of the flow rate control valve can be adjusted to adjust the feedwater flow rate from the first water supply passage 61 to the equipment, the lower limit of the feedwater flow rate can be made smaller, making it easier to use the device for supplying water to equipment that is expected to have a larger range between the upper and lower limits of the feedwater flow rate.

[0043] In the above embodiment, an example was described in which the on-off valve 53 provided in the second water supply passage 62 is controlled to be open or closed. However, the present invention is not limited to this, and may be a flow rate adjustment valve capable of adjusting the flow rate by adjusting the opening. For example, not only when it is determined in step S01 of FIG. 2 that the low combustion state is in transition to the high combustion state, but also when it is determined that the low combustion state is in transition to the medium combustion state, a predetermined flag may be set to ON in step S02, and the opening of the flow rate adjustment valve provided in the second water supply passage 62 may be adjusted so that water is supplied according to the combustion state of the boiler 1. This makes it possible to supply water at multiple flow rates according to the combustion state of the boiler 1.

[0044] In the above embodiment, a boiler is used as an example of the equipment, and an example has been described in which the boiler 1 is provided with a water supply device including the water supply system 5. However, the equipment is not limited to a boiler, and may be an evaporator of a fuel cell, and the present invention may be applied to a feedwater flow meter provided in a water supply system device used for the evaporator of the fuel cell.

[0045] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0046] 1. Boiler 2 Boiler body 3. Blower 30 Air supply line 4 Flue 5 Water supply device FM1 Water supply flow meter (1st flow rate measuring device) FM2 Water supply flow meter (second flow rate measuring device) 53 On-off valve 6 Water supply channel 60 Water Pump 61 1st water supply channel 62 2nd water supply channel

Claims

1. A water supply device that supplies water to an appliance, A first water supply channel; A first flow rate measuring device that measures a water supply flow rate of the first water supply passage; A second water supply passage different from the first water supply passage; A second flow rate measuring device that measures the water supply flow rate of the second water supply passage; an on-off valve for opening and closing the second water supply passage; When the device is in a first state, the on-off valve is closed to supply water to the device from the first water supply passage, and when the device is in a second state, the on-off valve is opened to supply water to the device from the first water supply passage and the second water supply passage, A water supply device that opens the on-off valve and supplies water from the first water supply passage and the second water supply passage when a predetermined condition is met even when the equipment is in the first state.

2. The water supply apparatus according to claim 1 , wherein the amount of water supplied from the second water supply passage is greater than the amount of water supplied from the first water supply passage.

3. The water supply device according to claim 1 , further comprising a flow rate regulating valve in the first water supply passage for regulating a water supply flow rate in the first water supply passage.

4. The equipment is a boiler equipped with the water supply device according to any one of claims 1 to 3, The second state is a state in which the amount of combustion is greater than that in the first state, The predetermined condition includes a condition that is satisfied when it is detected that the water level inside the boiler is lower than a predetermined low water level.

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