A boiler continuous blowdown flow measurement device and method

Abstract

The present application relates to a kind of boiler continuous blowdown flow measuring device and measuring method, for the measurement of continuous blowdown expansion vessel flow, including remote liquid level measuring cylinder and in-place liquid level measuring cylinder;Remote liquid level measuring cylinder is equipped with measuring device and control device;Measuring device includes remote liquid level measuring cylinder measurement result display instrument and remote liquid level measuring cylinder measurement 0 water level display instrument;Remote liquid level measuring cylinder top is equipped with air release valve;Air release valve includes valve body joint, valve body, sealing umbrella, guide column and sealing column;Continuous blowdown expansion vessel is equipped with drain pipeline assembly, drain pipeline assembly includes drain valve, drain pipe and water test valve;A kind of boiler continuous blowdown flow measuring method, including measurement preparation, the determination of measurement start time, measurement end time determination, calculate blowdown amount etc.The beneficial effects of the present application are that, by the measuring device and the measuring method provided, the flow of boiler continuous blowdown can be accurately calculated, and then it is judged whether the boiler is normal.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluid flow measurement, in particular to a boiler continuous blowdown flow measurement device and a measurement method. BACKGROUND

[0002] In order to ensure that the boiler water reaches a certain index, prevent scaling, ensure steam quality, prevent steam and water from coexisting, etc., the boiler is provided with a continuous blowdown expander and a periodic blowdown expander, which are referred to as continuous blowdown and periodic blowdown.

[0003] Since the entire process of boiler blowdown is accompanied by pressure reduction and expansion, the fluid is always in a two-phase flow of steam and liquid, and the existing technology does not have good measurement effect on two-phase flow. It is difficult to accurately measure the flow of blowdown fluid. Based on various algorithms, the measurement means is too complex and the parameters are too many. If one link does not have or deviates, it will lead to the inability to measure or the accuracy and reliability of the result is not high, and the anti-interference ability is poor. Therefore, it is a technical problem to be solved to provide a boiler blowdown fluid flow measurement device and a measurement method which can accurately measure the flow.

[0004] The closest prior art in the prior art is a circulating fluidized bed boiler ash flow measurement device with application number CN201120188342.2; it discloses a measuring pipe, an inlet section thermosensitive high-temperature thermocouple and an outlet section thermosensitive high-temperature thermocouple, wherein the measuring pipe is a spiral pipe coil; the temperature range of the inlet section thermosensitive high-temperature thermocouple is 0-1200℃; the temperature range of the outlet section thermosensitive high-temperature thermocouple is 0-800℃, this patent can only measure temperature, cannot measure flow, needs to be improved.

[0005] There is also a patent with application number CN201921651402.2, named a rich-oxygen combustion boiler medium flow measurement system, which discloses a rich-oxygen combustion boiler flue gas system, a primary air medium flow measurement system, a secondary air medium flow measurement system, and a circulating flue gas medium flow measurement system; the secondary air medium flow measurement system includes a secondary air total air duct medium flow measurement system and a secondary air branch air duct medium flow measurement system; the circulating flue gas medium flow measurement system includes a wet flue gas recirculation passage measurement system and a dry flue gas recirculation passage measurement system; the primary air medium flow measurement system, the secondary air medium flow measurement system, and the circulating flue gas medium flow measurement system send the measured medium flow parameters to a medium flow calculation system to obtain the medium flow of the rich-oxygen combustion boiler flue gas system; this patent only lists various flow measurement systems, does not disclose the specific structure, and cannot be truly implemented and landed, needs to be supplemented. SUMMARY

[0006] The technical problem solved by the present application is to provide a boiler continuous blowdown flow measuring device and a measuring method, which solves the problem that the flow cannot be accurately measured due to the existence of vapor-liquid two-phase flow in the pressure reduction and expansion process of the boiler continuous blowdown, and only measures the expansion vessel discharge liquid flow.

[0007] To solve the above technical problems, the present application provides the following technical solutions:

[0008] A boiler continuous blowdown flow measuring device for measuring the flow of a continuous blowdown expansion vessel and transmitting a measuring signal to a control center, comprising a remote liquid level measuring cylinder and an on-site liquid level measuring cylinder arranged in sequence on the same side of the continuous blowdown expansion vessel; the remote liquid level measuring cylinder and the on-site liquid level measuring cylinder have equal diameters;

[0009] The remote liquid level measuring cylinder is in communication with the on-site liquid level measuring cylinder and the continuous blowdown expansion vessel, respectively;

[0010] The remote liquid level measuring cylinder is provided with a measuring device and a control device; the measuring device is signal-connected with the control device, and the control device is signal-connected with the control center.

[0011] Further, the remote liquid level measuring cylinder, the on-site liquid level measuring cylinder and the continuous blowdown expansion vessel are all cylindrical;

[0012] A first upper communication pipe and a first lower communication pipe are arranged between the remote liquid level measuring cylinder and the continuous blowdown expansion vessel;

[0013] The first upper communication pipe is in communication with the upper part of the remote liquid level measuring cylinder and the upper part of the continuous blowdown expansion vessel, respectively;

[0014] The first lower communication pipe is in communication with the lower part of the remote liquid level measuring cylinder and the lower part of the continuous blowdown expansion vessel, respectively.

[0015] Further, a second upper communication pipe and a second lower communication pipe are arranged between the remote liquid level measuring cylinder and the on-site liquid level measuring cylinder;

[0016] The second upper communication pipe is in communication with the upper part of the remote liquid level measuring cylinder and the upper part of the on-site liquid level measuring cylinder, respectively;

[0017] The second lower communication pipe is in communication with the lower part of the remote liquid level measuring cylinder and the lower part of the on-site liquid level measuring cylinder, respectively.

[0018] Further, a first stop valve is arranged on the first upper communication pipe;

[0019] A second stop valve is arranged on the first lower communication pipe;

[0020] A third stop valve is arranged on the second upper communication pipe;

[0021] The fourth stop valve is arranged on the second lower communication pipe.

[0022] Further, the measuring device comprises a remote liquid level measuring cylinder measurement result display device arranged at the upper part of the remote liquid level measuring cylinder and a remote liquid level measuring cylinder 0 water level display device arranged at the bottom of the remote liquid level measuring cylinder; the remote liquid level measuring cylinder measurement result display device and the remote liquid level measuring cylinder 0 water level display device are signal connected with the control device.

[0023] Further, the top of the remote liquid level measuring cylinder is provided with a deflation valve.

[0024] Further, the deflation valve comprises a valve body joint in communication with the top of the remote liquid level measuring cylinder, a valve body fixedly connected with the valve body joint, a sealing umbrella arranged in the valve body, a guide column fixedly connected with the bottom of the sealing umbrella and a sealing column arranged at the top of the sealing umbrella; the top of the valve body is provided with a deflation hole, the sealing umbrella is in sliding connection with the deflation hole; the valve body joint is provided with a guide hole; the guide hole is in sliding connection with the guide column; the valve body joint is provided with a ventilation hole; the sealing umbrella is a hollow plastic structure.

[0025] Further, the continuous expansion vessel is provided with a drainage pipeline assembly, the drainage pipeline assembly comprises a drainage valve fixedly connected with the bottom of the continuous expansion vessel, a drainage pipe in communication with the drainage valve and a water testing valve in communication with the drainage pipe.

[0026] Further, the control device is a PLC controller, the PLC controller is provided with a communication module, the communication module is signal connected with the control center, the 0 water level electric contact display device and the remote liquid level measuring cylinder measurement result display device are signal connected with the PLC controller.

[0027] A continuous blowdown flow measurement method of a boiler,

[0028] Step S1, open the water testing valve, and determine whether there is water in the continuous expansion vessel; if yes, close the water testing valve; if not, continue to empty until there is water and then close;

[0029] Step S2, open the first and second cutoff valves; the 0 water level electric contact display device collects data, records the starting time t0 of measurement, and transmits the data to the controller;

[0030] Step S3, the water level rises, after the remote liquid level measuring cylinder measurement result display device measures water, records the ending time t2 of measurement, the remote liquid level measuring cylinder display device gives the liquid level difference h of the period, and transmits the data to the controller; close the first and second cutoff valves; complete the measurement;

[0031] Step S4, the continuous blowdown flash tank has an inner diameter R, and the blowdown flow rate Q is calculated according to the formula,

[0032] Q = π × R 2 / 4 × h / (t1-t0) ;

[0033] Step S5, the accuracy of the remote liquid level measuring cylinder is monitored by using the in-situ liquid level measuring cylinder.

[0034] The first and second cut-off valves are closed, and the third and fourth cut-off valves are opened, and the in-situ liquid level measuring cylinder displays the liquid level h1; if h = 2h1, it is indicated that the measurement result of the remote liquid level measuring cylinder is accurate; otherwise, it needs to be checked.

[0035] Compared with the prior art, the present application has the following beneficial effects:

[0036] 1) The present application bypasses the step of measuring the flow rate of the boiler continuous blowdown because of the existence of the vapor-liquid two-phase flow during the pressure reduction and expansion process. Only the flow rate of the expanded liquid is measured, and the vapor side is recycled, and it is not meaningful to measure the flow rate. The present application directly measures the change of the liquid level of the boiler continuous blowdown expansion tank by using the remote liquid level measuring cylinder and the in-situ liquid level measuring cylinder, and then obtains the flow rate of the boiler continuous blowdown water. Although the flow rate does not contain the expansion evaporation steam flow rate, the expansion evaporation flow rate is recycled in the deaerator, so that the measured flow rate is the actual blowdown flow rate. The flow rate obtained by measuring the change of the expansion tank liquid level successfully avoids the problem of difficult measurement of the flow rate of the vapor-liquid two-phase flow due to the pressure reduction and expansion.

[0037] 2) The present application can realize two kinds of measurement methods, remote and in-situ, which can be verified with each other and can be used as each other's backup.

[0038] 3) The present application has high safety factor, is simple and practical, has low cost, and has high reliability.

[0039] 4) The present application has universality, provides a new concern and direction for the measurement method of the fluid existing phase change due to pressure reduction and expansion, and can be expanded to most industrial and mining enterprises. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The figure is a structural schematic diagram of the present application;

[0041] Figure 2 The figure is a schematic diagram of the water level electric contact point position arrangement of the remote liquid level measuring cylinder 0;

[0042] Figure 3 The figure is a structural schematic diagram of the air release valve;

[0043] Figure 4 The figure is a flow chart of the use method of the present device.

[0044] EXPLANATION OF DRAWINGS

[0045] 1-continuous expansion vessel,

[0046] 2-remote liquid level measuring cylinder,

[0047] 3-in-situ liquid level measuring cylinder,

[0048] 4-first upper communication pipe,

[0049] 5-first stop valve,

[0050] 6-gas release valve,

[0051] 7-second upper communication pipe,

[0052] 8-third stop valve,

[0053] 9-remote liquid level measuring cylinder measurement result display instrument,

[0054] 10-second lower communication pipe,

[0055] 11-fourth stop valve,

[0056] 12 remote liquid level measuring cylinder 0 water level display instrument,

[0057] 13-second stop valve,

[0058] 14-first lower communication pipe,

[0059] 15-continuous expansion vessel blowdown pipe,

[0060] 16-continuous expansion vessel blowdown stop valve;

[0061] 17-continuous expansion vessel blowdown pipe water release valve. DETAILED DESCRIPTION

[0062] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application.

[0063] Embodiment 1

[0064] Please refer to Figures 1-4 shown,

[0065] The embodiment provides a continuous blowdown flow measuring device for a boiler, which is used for measuring the flow of a continuous expansion vessel 1 and transmitting a measuring signal to a control center, and comprises a remote liquid level measuring cylinder 2 and an in-situ liquid level measuring cylinder 3 arranged on the same side of the continuous expansion vessel 1 in sequence; the remote liquid level measuring cylinder 2 and the in-situ liquid level measuring cylinder 3 are equal in diameter;

[0066] The remote liquid level measuring cylinder 2 is in communication with the in-situ liquid level measuring cylinder 3 and the continuous expansion vessel 1 respectively;

[0067] The remote liquid level measuring cylinder 2 is provided with a measuring device and a control device; the measuring device is signal connected with the control device, and the control device is signal connected with a control center.

[0068] The remote liquid level measuring cylinder 2, the in-situ liquid level measuring cylinder 3 and the continuous discharge expander 1 are all cylindrical.

[0069] The remote liquid level measuring cylinder 2 and the continuous discharge expander 1 are provided with a first upper communication pipe 4 and a first lower communication pipe 14.

[0070] The first upper communication pipe 4 is respectively communicated with the upper part of the remote liquid level measuring cylinder 2 and the upper part of the continuous discharge expander 1.

[0071] The first lower communication pipe 14 is respectively communicated with the lower part of the remote liquid level measuring cylinder 2 and the lower part of the continuous discharge expander 1.

[0072] The remote liquid level measuring cylinder 2 and the in-situ liquid level measuring cylinder 3 are provided with a second upper communication pipe 7 and a second lower communication pipe 10.

[0073] The second upper communication pipe 7 is respectively communicated with the upper part of the remote liquid level measuring cylinder 2 and the upper part of the in-situ liquid level measuring cylinder 3.

[0074] The second lower communication pipe 10 is respectively communicated with the lower part of the remote liquid level measuring cylinder 2 and the lower part of the in-situ liquid level measuring cylinder 3.

[0075] The first upper communication pipe 4 is provided with a first stop valve 5.

[0076] The first lower communication pipe 14 is provided with a second stop valve 13.

[0077] The second upper communication pipe 7 is provided with a third stop valve 8.

[0078] The second lower communication pipe 10 is provided with a fourth stop valve 11.

[0079] The measuring device comprises a remote liquid level measuring cylinder measurement result display instrument 9 arranged at the upper part of the remote liquid level measuring cylinder 2 and a remote liquid level measuring cylinder 0 water level display instrument 12 arranged at the bottom of the remote liquid level measuring cylinder 2; the remote liquid level measuring cylinder measurement result display instrument 9 and the remote liquid level measuring cylinder 0 water level display instrument 12 are both signal connected with the control device.

[0080] The top of the remote liquid level measuring cylinder 2 is provided with a gas release valve 6.

[0081] The air release valve 6 includes a valve body joint 61 in communication with the top of the remote liquid level measuring cylinder 2, a valve body 64 in fixed communication with the valve body joint 61, a sealing umbrella 67 provided in the valve body 64, a guide column 69 fixedly connected to the bottom of the sealing umbrella 67, and a sealing column 66 provided at the top of the sealing umbrella 67; the valve body top is provided with an air release hole 65, the sealing column 66 is in sliding connection with the air release hole 65; the valve body joint 61 is provided with a guide hole 62; the guide hole 62 is in sliding connection with the guide column 69; the valve body joint 61 is provided with a vent hole 63; the sealing umbrella 67 is a hollow structure made of plastic.

[0082] The continuous drain expansion vessel 1 is provided with a drain pipeline assembly, which includes a drain valve 16 in fixed communication with the bottom of the continuous expansion vessel 1, a drain pipe 15 in communication with the drain valve 16, and a water test valve 17 in communication with the drain pipe 15.

[0083] The control device is a PLC controller, which is provided with a communication module in signal connection with a control center, and the water level electric contact display instrument 12 and the remote liquid level measuring cylinder measurement result display instrument 9 are in signal connection with the PLC controller.

[0084] A continuous drain flow measurement method for a boiler,

[0085] Step S1, open the water test valve 17 and determine whether there is water in the continuous expansion vessel 1; if there is water, close the water test valve 17; if there is no water, continue to empty until there is water and then close;

[0086] Step S2, open the first cutoff valve 5 and the second cutoff valve 13; the water level electric contact display instrument 12 collects data, records the start time t0 of measurement, and transmits the data to the controller;

[0087] Step S3, the water level rises, the remote liquid level measuring cylinder measurement result display instrument 9 records the end time t2 of measurement after measuring that there is water, the remote liquid level measuring cylinder display instrument 9 gives the liquid level difference h of this period of time and transmits the data to the controller; close the first cutoff valve 5 and the second cutoff valve 13; complete the measurement;

[0088] Step S4, the inner diameter of the continuous drain expansion vessel is R, and the continuous drain flow Q is calculated according to the formula,

[0089]

[0090] Step S5, use the on-site liquid level measuring cylinder 3 to monitor the accuracy of the remote liquid level measuring cylinder 2;

[0091] Close the first cut-off valve 5 and the second cut-off valve 13; open the third cut-off valve 8 and the fourth cut-off valve 11, and the local liquid level measuring cylinder 3 shows the liquid level h1; if h = 2h1, it indicates that the measurement result of the remote liquid level measuring cylinder 2 is accurate; otherwise, it needs to be checked.

[0092] 0The water level electric contact display instrument 12 and the measurement result display instrument 9 are remote water level instruments, the manufacturer is Wanhe Zhongyi, and the model is WH311.

[0093] The working process of the present application is as follows,

[0094] The device is connected with the continuous blowdown expander 1; when the continuous blowdown flow of the boiler is measured by the remote liquid level measuring cylinder 2 in the main control room, the operator first observes the water level of the continuous blowdown expander 1; when the water level of the continuous blowdown expander 1 is at the low water level, the expander drain valve 16 is closed; after the drain valve 16 is completely closed, the value of the measurement result display instrument 9 of the remote liquid level measuring cylinder 2 is read; according to the value of the measurement result display instrument 9, the liquid volume of the continuous blowdown expander 1 in this period of time is calculated combined with the geometric size (the radius of the inner barrel of the expander) of the continuous blowdown expander 1 cylinder, and the volume flow of blowdown is obtained by dividing the obtained liquid volume by the time interval.

[0095] Example 2

[0096] The present embodiment is basically the same as that of example 1,

[0097] The same is a boiler continuous blowdown flow measuring device for measuring the flow of the continuous blowdown expander 1 and transmitting the measurement signal to the control center, which comprises a remote liquid level measuring cylinder 2 and a local liquid level measuring cylinder 3 arranged in sequence on the same side of the continuous blowdown expander 1; the diameters of the remote liquid level measuring cylinder 2 and the local liquid level measuring cylinder 3 are equal;

[0098] The remote liquid level measuring cylinder 2 is in communication with the local liquid level measuring cylinder 3 and the continuous blowdown expander 1 respectively;

[0099] The remote liquid level measuring cylinder 2 is provided with a measuring device and a control device; the measuring device is signal connected with the control device, and the control device is signal connected with the control center.

[0100] The remote liquid level measuring cylinder 2, the local liquid level measuring cylinder 3 and the continuous blowdown expander 1 are all cylindrical;

[0101] The remote liquid level measuring cylinder 2 and the continuous blowdown expander 1 are provided with a first upper communication pipe 4 and a first lower communication pipe 14;

[0102] The first upper communication pipe 4 is in communication with the upper part of the remote liquid level measuring cylinder 2 and the upper part of the continuous blowdown expander 1 respectively;

[0103] The first lower communication pipe 14 respectively communicates with the lower part of the remote liquid level measuring cylinder 2 and the lower part of the continuous expansion vessel 1.

[0104] The second upper communication pipe 7 respectively communicates with the upper part of the remote liquid level measuring cylinder 2 and the upper part of the on-site liquid level measuring cylinder 3.

[0105] The second lower communication pipe 10 respectively communicates with the lower part of the remote liquid level measuring cylinder 2 and the lower part of the on-site liquid level measuring cylinder 3.

[0106] The second lower communication pipe 10 respectively communicates with the lower part of the remote liquid level measuring cylinder 2 and the lower part of the on-site liquid level measuring cylinder 3.

[0107] The first upper communication pipe 4 is provided with a first stop valve 5.

[0108] The first lower communication pipe 14 is provided with a second stop valve 13.

[0109] The second upper communication pipe 7 is provided with a third stop valve 8.

[0110] The second lower communication pipe 10 is provided with a fourth stop valve 11.

[0111] The measuring device includes a remote liquid level measuring cylinder measurement result display instrument 9 arranged at the upper part of the remote liquid level measuring cylinder 2 and a remote liquid level measuring cylinder 0 water level display instrument 12 arranged at the bottom of the remote liquid level measuring cylinder 2; the remote liquid level measuring cylinder measurement result display instrument 9 and the remote liquid level measuring cylinder 0 water level display instrument 12 are signal connected with a control device.

[0112] The top of the remote liquid level measuring cylinder 2 is provided with a gas release valve 6.

[0113] The gas release valve 6 includes a valve body joint 61 in communication with the top of the remote liquid level measuring cylinder 2, a valve body 64 fixedly communicated with the valve body joint 61, a sealing umbrella 67 arranged in the valve body 64, a guide column 69 fixedly connected with the bottom of the sealing umbrella 67, and a sealing column 66 arranged at the top of the sealing umbrella 67; the top of the valve body is provided with a gas release hole 65, the sealing column 66 is slidingly connected with the gas release hole 65; the valve body joint 61 is provided with a guide hole 62; the guide hole 62 is slidingly connected with the guide column 69; the valve body joint 61 is provided with a ventilation hole 63; the sealing umbrella 67 is a hollow plastic structure.

[0114] The continuous expansion vessel 1 is provided with a drainage pipeline assembly, which includes a drainage valve 16 fixedly communicated with the bottom of the continuous expansion vessel 1, a drainage pipe 15 communicated with the drainage valve 16, and a water testing valve 17 communicated with the drainage pipe 15.

[0115] The control device is a PLC controller, the PLC controller is provided with a communication module, the communication module is signal connected with a control center, the 0 water level electric contact display instrument 12 and the remote liquid level measuring cylinder measurement result display instrument 9 are signal connected with the PLC controller.

[0116] A boiler continuous blowdown flow measurement method,

[0117] Step S1, measurement preparation, opening the water test valve 17, judging whether there is water in the continuous expansion vessel 1 or not; if yes, closing the water test valve 17; if not, continuing to empty until there is water and then closing;

[0118] Step S2, determination of the measurement start time, opening the first cut-off valve 5 and the second cut-off valve 13; the 0 water level electric contact display instrument 12 collects data, records the measurement start time t0, and transmits the data to the controller;

[0119] Step S3, determination of the measurement end time, the water level rises, after the remote liquid level measuring cylinder measurement result display instrument 9 measures water, recording the measurement end time t2, the remote liquid level measuring cylinder display instrument 9 gives the liquid level difference h of the time and transmits the data to the controller; closing the first cut-off valve 5 and the second cut-off valve 13; completing the measurement;

[0120] Step S4, flow calculation, the continuous blowdown expansion vessel inner diameter is R, the continuous blowdown flow Q calculation formula is

[0121]

[0122] Step S5, instrument calibration; using the on-site liquid level measuring cylinder 3 to monitor the accuracy of the remote liquid level measuring cylinder 2;

[0123] Closing the first cut-off valve 5 and the second cut-off valve 13; opening the third cut-off valve 8 and the fourth cut-off valve 11, the on-site liquid level measuring cylinder 3 displays the liquid level h1; if h=2h1, it indicates that the measurement result display instrument 9 of the remote liquid level measuring cylinder 2 is accurate; otherwise, it needs to be checked.

[0124] The difference lies in that the first cut-off valve 5, the second cut-off valve 13, the third cut-off valve 8 and the fourth cut-off valve 11 are all electric valves, which are convenient to operate and save time.

[0125] The working principle of this embodiment is basically the same as that of embodiment 1, which will not be repeated here.

[0126] Embodiment 3

[0127] This embodiment explains the device and the measurement method in detail, which will be described in detail below,

[0128] For a long time, thermal power generating units are the main power supply units in China. In the thermal power generating units, the boiler is one of the three main equipments. In order to ensure that the water reaches a certain index, prevent scaling, ensure steam quality, prevent steam and water from coexisting, etc., the boiler is provided with a continuous blowdown expander and a regular blowdown expander. The continuous blowdown and regular blowdown of the boiler are almost indispensable processes for the operation of the unit. The water for the boiler is sourced from high-quality desalted water, so the monitoring of the size of the blowdown flow is one of the important indicators for water and energy saving in power plants. Therefore, accurate measurement of the blowdown water flow is of great significance for water and energy saving in power plants.

[0129] However, since the boiler blowdown process is a pressure reduction and expansion process, the boiler water starts to be pressure reduced and expanded as soon as it enters the blowdown pipeline. A part of the liquid evaporates into steam, and the flow in the pipeline is a vapor-liquid two-phase flow. The deviation of the value obtained by the existing measurement means for the vapor-liquid two-phase flow from the true flow is large, and the reliability is not high, which is difficult to scientifically guide and reference for water and energy saving in power plants. The blowdown flow calculated by other methods is not satisfactory due to the constraints and influences of the system, electronic components, anti-interference, etc.

[0130] The measurement device well avoids the measurement difficulty of the vapor-liquid two-phase flow, grasps the essence of things, and directly measures the change of the liquid level of the continuous expander 1, and indirectly obtains the blowdown flow. Since the evaporated steam in the continuous blowdown expander 1 is recycled, this part of the flow can be ignored.

[0131] Specifically, the boiler continuous blowdown blowdown water enters the continuous blowdown expander 1 through the pipeline. After entering the continuous blowdown expander 1, a part of the liquid evaporates and enters the deaerator for recycling through the upper pipeline of the expander. Another part of the liquid is stored in the continuous blowdown expander 1, and the liquid level in the continuous blowdown expander 1 can be adjusted by the lower drain valve 16 of the expander 1. Therefore, the blowdown water flow can be obtained by the change rate of the liquid level of the continuous blowdown expander 1. The continuous blowdown expander 1 generally has a liquid level meter, but the liquid level meter provided with the continuous blowdown expander 1 is generally small and narrow (because the expander is a pressure vessel), and many of them are blurred with aging, and do not have the conditions for accurately measuring the change of the liquid level of the expander.

[0132] The device of the present application connects the continuous discharge expansion vessel 1 and the remote liquid level measuring cylinder 2 through the first upper communication pipe 4 and the first lower communication pipe 14, and installs the stop valves 5 and 13 on the communication pipes. The first lower communication pipe 14 is installed at a distance of 50 mm from the bottom of the continuous discharge expansion vessel 1. The bottom of the remote liquid level measuring cylinder 2 is provided with an electric contact water level display 12 for recording the time when water is seen at the bottom of the remote liquid level measuring cylinder 2 as the starting time of the increase of the measured liquid level. The upper part of the remote liquid level measuring cylinder 2 is also connected with the upper part of the continuous discharge expansion vessel 1 through the upper communication pipe, which ensures that the remote liquid level measuring cylinder 2 and the expansion vessel 1 are in the same pressure condition during the measurement. The remote liquid level measuring cylinder 2 is provided with a remote liquid level measuring cylinder measurement result display instrument 9, which can remotely display the liquid level value.

[0133] The upper and lower parts of the remote liquid level measuring cylinder 2 are also connected with the on-site liquid level measuring device 3 through the communication pipes, and the stop valves 8 and 11 are installed on the communication pipes to isolate the two. The upper part of the remote liquid level measuring cylinder 2 is provided with a gas release valve 6. The main purpose of the on-site liquid level measuring cylinder 3 is to periodically verify the accuracy of the liquid level difference value measured by the remote liquid level measuring cylinder 2 and to serve as a backup for the remote measurement. Since it is a glass tube that can see the internal water column, the pressure bearing capacity is limited, so it is connected with the remote measuring cylinder 3 through the communication pipe, and the stop valve is installed on the communication pipe to isolate the remote measuring cylinder 3;

[0134] When verifying the accuracy of the liquid level difference value measured by the remote measuring cylinder 2, the on-site liquid level measuring cylinder 3 is first isolated, the water level of the continuous discharge expansion vessel 1 is adjusted to the water level at which the water level display of the electric contact 12 disappears, the expansion vessel drainage valve 16 is closed, the time when the water level display of the electric contact 0 12 disappears is recorded, at this time the liquid level is 0, after a period of time (the specific time depends on the water level of the on-site expansion vessel) the liquid level rises to a certain value and stops recording, the stop valves 5 and 13 on the communication pipes between the remote liquid level measuring cylinder 2 and the continuous discharge expansion vessel 1 are quickly closed, after closing, wait for a while, then release the pressure of the remote measuring cylinder 2 through the top gas release valve, the pressure release should be slow to prevent water from affecting the liquid level, open the stop valves 8 and 11 between the on-site measuring cylinder 3 and the remote measuring cylinder 2, measure the liquid level height of the glass tube (the diameter of the inner barrel of the remote liquid level measuring cylinder 2 and the on-site liquid level measuring cylinder 3 is the same, the valve on the lower communication pipe is close to the on-site liquid level measuring cylinder 3, after ensuring these two points, opening the valves on the upper and lower communication pipes between the on-site liquid level measuring cylinder 3 and the remote liquid level measuring cylinder 2 can ensure that the liquid level of the on-site liquid level measuring cylinder 3 is half of the actual water level in the remote liquid level measuring cylinder 2), multiply this height by 2 and compare it with the value measured by the remote measuring cylinder, if they are equal, it means that the value measured by the remote measuring cylinder is accurate. With the liquid level difference value, the geometric size of the continuous discharge expansion vessel 1 and the time used for the liquid level difference value, the sewage water flow can be obtained.

[0135] Work flow: Remote liquid level measuring cylinder 2 is connected with continuous discharge expansion vessel 1 through connecting pipe 4, 14. On-site liquid level measuring cylinder 3 is connected with remote liquid level measuring cylinder 2 through connecting pipe 7, 10. When measuring the continuous discharge flow of boiler in main control room through remote liquid level measuring cylinder 2, the operator first observes the water level of continuous discharge expansion vessel 1. When the water level of continuous discharge expansion vessel 1 is at low water level, the expansion vessel drain valve 16 is closed. After the drain valve 16 is completely closed, the liquid level difference 9 of remote liquid level measuring cylinder 2 in a period of time is read. The liquid volume in the expansion vessel in the period of time is calculated according to the liquid level difference 9 and the geometric size of expansion vessel 1 (the radius of the inner barrel of expansion vessel). The volume of the liquid is divided by the time interval to obtain the volume flow of the discharge.

[0136] When it is necessary to verify the accuracy of the measurement result of remote liquid level measuring cylinder, on-site liquid level measuring cylinder 3 is needed. When on-site liquid level measuring cylinder 3 is used, (the third stop valve 8 and the fourth stop valve 11 are normally closed. Only when on-site liquid level measuring cylinder 3 is used to measure, the valve 5 and the valve 13 are closed to prevent the glass tube measuring cylinder 3 from being insufficient in strength.) The water in the continuous discharge expansion vessel 1 is discharged through the drain pipe 15 by opening the drain valve 16. Then the valve 16 is closed. When the valve 16 is completely closed, the pipe 15 is not draining (whether the valve 16 is tight and whether the drain pipe 15 has water can be judged by the valve 17. The valve 17 is a drain pipe which is open to the air). At this time, the water level of the continuous discharge expansion vessel 1 gradually rises. When the 0 water level electric contact point display instrument 12 light is on, the time is recorded as the starting time of the measurement of the liquid level difference. Then a period of time is recorded according to the site conditions. The main observation is the growth rate and the height of the liquid level of the continuous discharge expansion vessel 1. The safety of the unit is the premise. In the case of ensuring the safety of the unit, the liquid level difference is as large as possible. We want the change rate of the liquid level difference. The value obtained is more accurate. If the site conditions do not allow the liquid level difference to be large, the small liquid level difference also does not affect the obtained flow value. When the recording is finished, the stop valves 5 and 13 are closed. At this time, the remote liquid level measuring cylinder 2 is closed with a certain height of water column. The remote liquid level measuring cylinder 2 gives the liquid level difference in the recording period. Combined with the recording time and the diameter of the inner barrel of the continuous discharge expansion vessel 1, the volume flow value 9 of the discharge obtained by the remote liquid level measuring cylinder 2 is calculated. Then the remote liquid level measuring cylinder 2 is slowly released by the upper air release valve 6. The pressure is released after a few moments. Then the air release valve 17 is closed. The valves 8 and 11 are opened. At this time, the on-site liquid level measuring cylinder 3 will show a liquid level. The liquid level should be half of the actual liquid level of the remote liquid level measuring cylinder. It also represents half of the liquid level increase of the continuous discharge expansion vessel 1 in the recording period. Similarly, the actual discharge flow of the continuous discharge is calculated. Compared with the discharge flow obtained by the remote measuring cylinder 2, it can be seen whether the measurement of the remote liquid level cylinder is accurate or not.

[0137] The working principle of this embodiment is basically the same as that of embodiment 1. Here is not repeated.

[0138] The above describes the preferred embodiments of the present application in detail, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application. At present, the technical scheme of the present application has been pilot tested, i.e., small-scale experiments before large-scale production of the product; after the pilot test is completed, user use research is carried out in a small range, and the research result shows that the user satisfaction is high; now, preparations for formal production of the product for industrialization are being made.

[0139] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; as those skilled in the art, it is obvious to combine the technical solutions of the present application. These modifications or replacements do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A boiler continuous blowdown flow measurement device, used for measuring the flow of a continuous blowdown expansion tank (1) and transmitting the measurement signal to a control center, characterized in that: It includes a remote liquid level measuring cylinder (2) and a local liquid level measuring cylinder (3) arranged sequentially on the same side of the continuous expansion container (1); the remote liquid level measuring cylinder (2) and the local liquid level measuring cylinder (3) have the same diameter; The remote liquid level measuring cylinder (2) is connected to the local liquid level measuring cylinder (3) and the continuous expansion container (1); The remote liquid level measuring cylinder (2) is equipped with a measuring device and a control device; the measuring device and the control device are connected by signal, and the control device is connected by signal to the control center; The top of the remote liquid level measuring cylinder (2) is equipped with a vent valve (6); The vent valve (6) includes a valve body connector (61) communicating with the top of the remote liquid level measuring cylinder (2), a valve body (64) fixedly communicating with the valve body connector (61), a sealing umbrella (67) disposed in the valve body (64), a guide post (69) fixedly connected to the bottom of the sealing umbrella (67), and a sealing post (66) disposed at the top of the sealing umbrella (67); the top of the valve body is provided with a vent hole (65), and the sealing post (66) is slidably connected to the vent hole (65); the valve body connector (61) is provided with a guide hole (62); the guide hole (62) is slidably connected to the guide post (69); the valve body connector (61) is provided with a vent hole (63); the sealing umbrella (67) is a hollow plastic structure.

2. The boiler continuous blowdown flow measurement device according to claim 1, characterized in that: The remote liquid level measuring cylinder (2), the local liquid level measuring cylinder (3), and the continuous expansion container (1) are all cylindrical; The remote liquid level measuring cylinder (2) and the continuous expansion container (1) are provided with a first upper connecting pipe (4) and a first lower connecting pipe (14). The first upper connecting pipe (4) is connected to the upper part of the remote liquid level measuring cylinder (2) and the upper part of the continuous expansion container (1); The first lower connecting pipe (14) is connected to the lower part of the remote liquid level measuring cylinder (2) and the lower part of the continuous expansion container (1).

3. The boiler continuous blowdown flow measurement device according to claim 2, characterized in that: A second upper connecting pipe (7) and a second lower connecting pipe (10) are provided between the remote liquid level measuring cylinder (2) and the local liquid level measuring cylinder (3). The second upper connecting pipe (7) is connected to the upper part of the remote liquid level measuring cylinder (2) and the upper part of the local liquid level measuring cylinder (3), respectively; The second lower connecting pipe (10) is connected to the lower part of the remote liquid level measuring cylinder (2) and the lower part of the local liquid level measuring cylinder (3), respectively.

4. The boiler continuous blowdown flow measurement device according to claim 3, characterized in that: A first shut-off valve (5) is provided on the first upper connecting pipe (4). A second shut-off valve (13) is provided on the first lower connecting pipe (14); A third shut-off valve (8) is provided on the second upper connecting pipe (7); A fourth shut-off valve (11) is provided on the second lower connecting pipe (10).

5. The boiler continuous blowdown flow measurement device according to claim 4, characterized in that: The measuring device includes a remote liquid level measuring cylinder measurement result display instrument (9) located on the upper part of the remote liquid level measuring cylinder (2) and a remote liquid level measuring cylinder zero water level display instrument (12) located at the bottom of the remote liquid level measuring cylinder (2); both the remote liquid level measuring cylinder measurement result display instrument (9) and the remote liquid level measuring cylinder zero water level display instrument (12) are connected to the control device via signal.

6. The boiler continuous blowdown flow measurement device according to claim 5, characterized in that: The continuous expansion container (1) is provided with a drainage pipe assembly, which includes a drainage valve (16) fixedly connected to the bottom of the continuous expansion container (1), a drainage pipe (15) connected to the drainage valve (16), and a test valve (17) connected to the drainage pipe (15).

7. The boiler continuous blowdown flow measurement device according to claim 6, characterized in that: The control device is a PLC controller. The PLC controller is equipped with a communication module, which is connected to the control center. The 0 water level display (12) and the remote liquid level measuring cylinder measurement result display (9) are connected to the PLC controller.

8. A method for measuring continuous boiler blowdown flow rate, using the continuous boiler blowdown flow rate measuring device according to any one of claims 1-7, characterized in that, include, Step S1, measurement preparation: Open the test valve (17) to determine whether there is water in the continuous expansion container (1); if there is water, close the test valve (17); if there is no water, continue to drain until there is water and then close it. Step S2: Determine the measurement start time t0, open the first shut-off valve (5) and the second shut-off valve (13); the 0 water level indicator (12) collects data, records the measurement start time t0, and transmits the data to the controller; Step S3, Determining the end time of measurement; As the water level rises, the remote liquid level measuring cylinder measurement result display instrument (9) detects the presence of water and records the end time t2 of the measurement. The remote liquid level measuring cylinder measurement result display instrument (9) provides the liquid level difference h during this recorded period and transmits the data to the controller; Close the first shut-off valve (5) and the second shut-off valve (13); Complete the measurement; Step S4, calculate the sewage discharge volume. The inner diameter of the continuous sewage discharge expansion container is R, and the formula for calculating the continuous sewage discharge flow rate Q is as follows: ； Step S5, Instrument calibration; The accuracy of the remote liquid level measuring cylinder (2) is monitored using the local liquid level measuring cylinder (3); Close the first shut-off valve (5) and the second shut-off valve (13); open the third shut-off valve (8) and the fourth shut-off valve (11), and the local liquid level measuring cylinder (3) displays the liquid level h1; if h=2h1, it means that the measurement result display instrument (9) of the remote liquid level measuring cylinder (2) is accurate; otherwise, it needs to be checked.

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