CN214066824U

CN214066824U - Limestone slurry density measurement system

Info

Publication number: CN214066824U
Application number: CN202023169791.0U
Authority: CN
Inventors: 林斌; 郑仁和; 王震皓; 翁武强
Original assignee: Huaneng Fujian Zhangzhou Energy Co ltd
Current assignee: Huaneng Fujian Zhangzhou Energy Co ltd
Priority date: 2020-12-24
Filing date: 2020-12-24
Publication date: 2021-08-27
Anticipated expiration: 2030-12-24

Abstract

The utility model relates to a limestone slurry density measuring system, which comprises a slurry pipeline, a measuring branch pipe, a differential pressure transmitter and a water seal mechanism; the measuring branch pipe is in a door shape, and two ends of the measuring branch pipe are respectively communicated with the slurry pipeline; a measuring section is arranged on one section of the measuring branch pipe close to the inlet of the slurry pipeline; the differential pressure transmitter is respectively provided with two capillaries, the tail end of each capillary is respectively fixed with an installation flange, and the middle part of the end surface of the tail end of the installation flange is provided with an induction diaphragm; the water seal mechanism comprises a sampling pipe and a connecting flange fixed with one end of the sampling pipe; a sampling hole and a water seal section which are communicated with each other are arranged in the sampling pipe, and the caliber of the tail end of the sampling hole is gradually increased towards the water seal section; the connecting flange is provided with a through flange hole communicated with the water seal section; the sampling hole is communicated with the measuring section; the connecting flange is fixed with the mounting flange, and the sensing diaphragm covers the flange hole; the connecting flange is provided with a back flushing port; one end of the back flushing port is communicated with the water seal section, and the other end of the back flushing port is communicated with a flushing pipeline.

Description

Limestone slurry density measurement system

Technical Field

The utility model relates to a limestone slurry density measurement system belongs to thick liquid density measurement technical field.

Background

At present, the atmospheric pollution situation is severe, and the coal-fired boiler is one of main emission sources of pollutants such as smoke dust, sulfur dioxide, nitrogen oxides and the like, so that the smoke of the coal-fired boiler in a thermal power plant and the like is subjected to near zero emission, ultralow emission and other hard indexes.

The wet calcium method (limestone-gypsum method) desulfurization technology is the most mature desulfurization technology in the world and the most stable desulfurization technology in the running state, and can well meet the current environmental protection index requirements. In a large-scale thermal power plant desulfurization device, more than nine times of desulfurization processes are adopted by limestone-gypsum wet flue gas desulfurization, one of core indexes of wet desulfurization is limestone slurry quality, and limestone slurry density is an important parameter for representing limestone slurry quality.

Because of the corrosivity and abrasiveness of the limestone slurry of the desulfurization system and the high solid content rate (up to 30%), and because of the large amount of bubbles in the slurry, the conventional detection method cannot be adopted, and the selection of the densimeter is greatly limited. At present, three methods for measuring the density of the slurry of the desulfurization system are common, namely a differential pressure method, a Coriolis mass flow method and a gamma-ray radiation absorption measurement method, but the methods cannot accurately and reliably measure the density of the slurry due to the defects of the methods.

Firstly, a differential pressure method: the method is an indirect measurement method, and the pressure difference between different depths of limestone slurry is measured by a differential pressure transmitter and then is measured according to the pressure difference

The density is calculated.

Wherein: Δ p is the differential pressure value between different depths, H is the depth difference between different depths, and g is the gravitational acceleration.

The results measured by the differential pressure method are true and reliable, but are limited by the fact that the limestone slurry contains air bubbles which influence the density value of the limestone slurry to a certain extent. In addition, the gas is gathered near the pressure sensing diaphragm of the differential pressure transmitter to influence the measurement result, and substances which are easy to scale in slurry can be attached to the measurement probe after long-term operation, so that the data of the instrument is inaccurate or even completely inaccurate. During on-line continuous measurement, if the flow velocity in the pipe is higher, and the flow velocities near the two pressure sensing diaphragms of the differential pressure transmitter are different, errors can be generated due to dynamic pressure.

And II, a Coriolis force mass flow method: when the slurry flows through the measuring tube with the bending degree, a Coriolis force vertical to the medium flow direction is generated, under the action of Coriolis force, the measuring tube continuously vibrates at a certain resonant frequency, the vibration frequency changes along with the density change of the fluid, and therefore the resonant frequency is a function of the density of the fluid, and a corresponding density output signal can be obtained.

The measurement result of the Coriolis mass flow densimeter is only related to density, the measurement precision is high, and the applicable slurry density range is wide. However, the coriolis force mass flow method cannot completely eliminate the influence of the suspended bubbles in the slurry, and has the requirement of vibration starting speed, and the flow rate is relatively high, so that the abrasion to the pipeline is very high, particularly, the zero point of measurement drifts along with the gradual abrasion in the use process, the phenomena of inaccurate measurement and frequent damage to spare parts and spare parts often occur in the follow-up process, and the continuous verification and the replacement of new spare parts are required. Therefore, the densimeter has unstable performance, poor reliability and serious abrasion of a measuring pipeline, needs to frequently replace spare parts and has extremely high maintenance cost.

And thirdly, gamma ray radiation absorptiometry: the nuclear radiation (usually gamma ray) emitted by a nuclear radiation source passes through a medium in a pipeline, one part of the nuclear radiation passes through the medium, the other part of the nuclear radiation passes through a detector arranged on the other side of the pipeline, the radiation absorbed by the medium and the density of the medium to be detected show an exponential absorption law, namely, the projection intensity of the radiation shows an exponential attenuation along with the increase of the concentration of solid matters in the medium, and under the condition that the intensity of the radiation emitted by a nuclear radiation source and the absorption coefficient of the medium are known, the density of the slurry flowing through the pipeline can be detected as long as the intensity of the transmitted radiation is detected by a radiation receiver.

When the density is measured by adopting a gamma-ray radiation absorption measurement method, the method is not influenced by the factors of pressure, temperature, flow velocity and the like of the slurry, and the maintenance amount of equipment is small. However, it does not distinguish between suspended and dissolved solids, and in particular gives an error signal in the event of condensation in the conduit, and above all there is a risk of radioactive material being used and it also requires evidence of radioactive material use.

In conclusion, both gamma-ray radiation absorptiometry and coriolis force mass flow have problems that cannot be solved. While relatively speaking, differential pressure methods, if they solve the problems encountered in measurement, will output accurate and reliable measurement parameters.

SUMMERY OF THE UTILITY MODEL

In order to overcome the problems, the utility model provides a limestone slurry density measuring system which can stably and accurately measure the density of limestone slurry, effectively solve the influence of bubbles contained in the limestone slurry on the density and prevent gas from gathering on a pressure sensing diaphragm of a differential pressure transmitter; and meanwhile, the long-term operation is ensured, substances which are easy to scale in the slurry cannot be attached to the measuring probe or block a sampling pipeline, and the measurement deviation caused by different flow velocities at different positions due to high flow velocity in the pipeline is eliminated.

The technical scheme of the utility model as follows:

a limestone slurry density measuring system comprises a slurry pipeline, a measuring branch pipe, a differential pressure transmitter and a water seal mechanism; the measuring branch pipe is in a door shape, and two ends of the measuring branch pipe are respectively communicated with the slurry pipeline; a measuring section is arranged on one section of the measuring branch pipe close to the inlet of the slurry pipeline; one ends of the two water seal mechanisms are respectively fixed with two ends of the differential pressure transmitter, and the other ends of the two water seal mechanisms are respectively communicated with two ends of the measuring section; the differential pressure transmitter is respectively provided with two capillaries, the tail end of each capillary is respectively fixed with an installation flange, and the middle part of the end face of the tail end of the installation flange is provided with an induction diaphragm; the water seal mechanism comprises a sampling pipe and a connecting flange fixed with one end of the sampling pipe; a sampling hole and a water seal section which are communicated with each other are arranged in the sampling pipe, and the caliber of the tail end of the sampling hole is gradually increased towards the water seal section; the connecting flange is provided with a through flange hole communicated with the water seal section; the sampling hole is communicated with the measuring section; the connecting flange is fixed with the mounting flange, and the sensing membrane covers the flange hole; the upper part of the connecting flange is also provided with a back flushing port; one end of the backflushing port is communicated with the water seal section, and the other end of the backflushing port is communicated with a flushing pipeline.

Further, the device also comprises a gas collector; one end of the gas collector is communicated with the flushing pipeline, and the other end of the gas collector is arranged on the back flushing port.

Further, the system also comprises a PLC control system; the slurry pipeline is provided with a first electric ball valve which is positioned between two connecting parts of the slurry pipeline and the measuring branch pipe; a second electric ball valve is arranged on one section of the measuring branch pipe close to the outlet of the slurry pipeline; a flushing electromagnetic valve is arranged on the flushing pipeline; the flushing electromagnetic valve and the back flushing port are respectively positioned on two sides of the gas collector; the PLC control system is in electrical signal connection with the differential pressure transmitter; the PLC control system is respectively in electric signal connection with the first electric ball valve, the second electric ball valve and the flushing electromagnetic valve and respectively controls the opening and closing of the first electric ball valve, the second electric ball valve and the flushing electromagnetic valve.

Furthermore, an expanding conversion head and a reducing conversion head are arranged on the measuring section; the diameter-expanding conversion head is positioned at one end of the measuring section close to the slurry pipeline inlet, and the caliber of the diameter-expanding conversion head gradually increases towards the measuring section; the reducing conversion head is positioned at the other end of the measuring section, and the caliber of the reducing conversion head gradually increases towards the measuring section.

Furthermore, the caliber of the gas collector is gradually reduced from the middle to two sides.

Furthermore, the flange hole and the back flushing opening are provided with tapers; the caliber of the flange hole is gradually reduced from one side communicated with the water seal section to the side connected with the induction membrane; the caliber of the backflushing opening is gradually increased from one side communicated with the water seal section to one side close to the gas collector.

Furthermore, the slurry pipeline is communicated with the measuring branch pipe through a branch tee.

The utility model discloses following beneficial effect has:

1. the limestone slurry density measuring system can stably and accurately measure the density of limestone slurry, effectively solve the influence of bubbles contained in the limestone slurry on the density and prevent gas from gathering on a pressure sensing diaphragm of a differential pressure transmitter; and meanwhile, the long-term operation is ensured, substances which are easy to scale in the slurry cannot be attached to the measuring probe or block a sampling pipeline, and the measurement deviation caused by different flow velocities at different positions due to high flow velocity in the pipeline is eliminated.

2. The sampling pipe is internally provided with a water seal, so that the scale formation of limestone slurry on the sensing diaphragm can be reduced, the gas contained in the slurry enters the sampling pipe, the time required for the solute in the slurry to enter the sampling pipe section through the diffusion effect can be longer, and the influence caused by the limestone slurry attached to the surface of the sensing diaphragm of the differential pressure transmitter is reduced.

3. The gas collector is arranged at the tail end of the water seal section and in front of the sensing diaphragm, and if gas enters the sampling tube in a non-flushing state, the gas can be automatically gathered on the gas collector under the action of gravity, so that the sensing diaphragm is ensured to be free of gas, and the influence of measurement errors of the differential pressure transmitter caused by gathering of the gas in a medium near the sensing diaphragm of the differential pressure transmitter is reduced.

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention.

Fig. 2 is a partially enlarged view of a portion a of fig. 1.

Fig. 3 is a schematic structural diagram of the gas collector.

Fig. 4 is a schematic structural diagram of a diameter expanding conversion head of a measuring section.

The reference numbers in the figures denote:

1. a slurry conduit; 11. a first electrically powered ball valve; 2. measuring branch pipes; 21. a measuring section; 22. expanding the diameter of the conversion head; 23. a reducing conversion head; 24. a second electrically operated ball valve; 25. a branch tee joint; 3. a differential pressure transmitter; 31. a capillary tube; 32. installing a flange; 33. an induction diaphragm; 4. a water seal mechanism; 41. a sampling tube; 42. a connecting flange; 43. a sampling hole; 44. a water seal section; 45. a flange hole; 46. back flushing the opening; 47. flushing the pipeline; 48. flushing the electromagnetic valve; 49. a gas collector; 5. and (4) a PLC control system.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

In fig. 1, X represents an inlet of the slurry, and Y represents an outlet of the slurry.

Referring to fig. 1-4, a limestone slurry density measurement system comprises a slurry pipeline 1, a measurement branch pipe 2, a differential pressure transmitter 3 and a water seal mechanism 4; the measuring branch pipe 2 is in a shape of a Chinese character 'men', and two ends of the measuring branch pipe 2 are respectively communicated with the slurry pipeline 1; a measuring section 21 is arranged on one section of the measuring branch pipe 2 close to the inlet of the slurry pipeline 1; one ends of the two water seal mechanisms 4 are respectively fixed with two ends of the differential pressure transmitter 3, and the other ends of the two water seal mechanisms are respectively communicated with two ends of the measuring section 21; the differential pressure transmitter 3 is respectively provided with two capillaries 31, the tail end of each capillary 31 is respectively fixed with an installation flange 32, and the middle part of the end face of the tail end of the installation flange 32 is provided with an induction diaphragm 33; the water seal mechanism 4 comprises a sampling pipe 41 and a connecting flange 42 fixed with one end of the sampling pipe 41; a sampling hole 43 and a water seal section 44 which are communicated with each other are arranged in the sampling pipe 41, and the caliber of the tail end of the sampling hole 43 is gradually increased towards the water seal section 44; the connecting flange 42 is provided with a through flange hole 45 communicated with the water seal section 44; the sampling hole 43 communicates with the measuring section 21; the connecting flange 42 is fixed with the mounting flange 32, and the sensing diaphragm 33 covers the flange hole 45; the upper part of the connecting flange 42 is also provided with a back flushing port 46; the backflush port 46 is connected to the water seal section 44 at one end and to a flushing line 47 at the other end.

According to the above description, the limestone slurry density measurement system mainly utilizes the principle of the differential pressure method, and then the slurry to be measured is sampled into the pipeline of the measurement device (i.e. the measurement branch pipe 2) through a bypass (the principle of the Cochinskite force mass flow method). The limestone slurry density measuring system comprises a slurry pipeline 1, a measuring branch pipe 2, a differential pressure transmitter 3 and a water seal mechanism 4. The whole measuring branch pipe 2 is in a door shape, and two ends of the measuring branch pipe are communicated with the slurry pipeline 1; a water seal mechanism 4 is respectively arranged on the high pressure side and the low pressure side of the differential pressure transmitter 3 correspondingly; the water seal mechanism 4 comprises a sampling pipe 41 and a connecting flange 42, a sampling hole 43 and a water seal section 44 are arranged in the sampling pipe 41, a flange hole 45 and a back flushing port 46 are arranged on the connecting flange 42, the connecting flange 42 is fixed with the mounting flange 32, the sensing membrane 33 covers the flange hole 45, one end of the back flushing port 46 is communicated with the water seal section 44, and the other end of the back flushing port is communicated with a flushing pipeline 47. Thus, the flushing water enters the connecting flange 42 of the water sealing mechanism 4 at the high pressure side and the low pressure side respectively through the flushing pipeline 47 to flush the sensing diaphragm 33 on the mounting flange 32; meanwhile, because the diameter (40 mm-50 mm) of the water seal section 44 is far greater than the diameter (10 mm-15 mm) of the sampling hole 43, flushing water is filled between the limestone slurry and the sensing diaphragm 33 of the differential pressure transmitter 3, a water seal is formed in the sampling pipe 41, scaling of the limestone slurry on the sensing diaphragm 33 can be reduced, gas contained in the slurry is reduced from entering the sampling pipe 41, time required for solute in the slurry to enter the sampling pipe 41 through diffusion is longer, and influence caused by the fact that the limestone slurry is attached to the surface of the sensing diaphragm 33 of the differential pressure transmitter 3 is reduced.

Further, a gas collector 49 is also included; one end of the gas collector 49 is communicated with the flushing pipeline 47, and the other end is arranged on the back flushing port 46. The gas collector 49 is arranged at the tail end of the water seal section 44 and in front of the sensing diaphragm 33, and if gas enters the sampling tube 41 in a non-flushing state, the gas can be automatically gathered on the gas collector 49 under the action of gravity, so that the sensing diaphragm 33 is ensured to be free of gas, and the measurement error of the differential pressure transmitter 3 caused by the fact that the gas in a medium is gathered near the sensing diaphragm 33 of the differential pressure transmitter 3 is reduced.

Further, the system also comprises a PLC control system 5; a first electric ball valve 11 is arranged on the slurry pipeline 1, and the first electric ball valve 11 is positioned between two connecting positions of the slurry pipeline 1 and the measuring branch pipe 2; a second electric ball valve 24 is arranged on one section of the measuring branch pipe 2 close to the outlet of the slurry pipeline 1; a flushing electromagnetic valve 48 is arranged on the flushing pipeline 47; the flushing electromagnetic valve 48 and the back flushing port 46 are respectively positioned at two sides of the gas collector 49; the PLC control system 5 is in electrical signal connection with the differential pressure transmitter 3; the PLC control system 5 is electrically connected to the first electric ball valve 11, the second electric ball valve 24, and the flushing solenoid valve 48, and controls the opening and closing of the first electric ball valve 11, the second electric ball valve 24, and the flushing solenoid valve 48, respectively.

Furthermore, the measuring section 21 is provided with an expanding conversion head 22 and a reducing conversion head 23; the diameter-expanding conversion head 22 is positioned at one end of the measuring section 21 close to the inlet of the slurry pipeline 1, and the caliber of the diameter-expanding conversion head 22 gradually increases towards the measuring section 21; the reducing conversion head 23 is positioned at the other end of the measuring section 21, and the caliber of the reducing conversion head 23 gradually increases toward the measuring section 21. The measurement section 21 is provided with the expanding conversion head 22 and the reducing conversion head 23, so that when the density of the slurry is measured, bubbles contained in the slurry can continuously rise to the reducing conversion head 23 from the branch tee 25 under the action of gravity and are gathered at the bent pipe of the measuring branch pipe 2 in a door shape of the reducing conversion head 23, the content of the bubbles in the slurry on the measurement section 21 is reduced, and the measurement precision is improved; meanwhile, in the measurement process, if impurities with large volume cannot be taken away along with the flowing of the slurry (especially for a vertical pipeline), the impurities can fall back to the slurry through the expanding conversion head 22 to enter the inlet section of the measurement branch pipe 2, so that the influence of solid impurities on the measurement is reduced.

In particular, in this limestone slurry density measurement system, the inner wall of the diameter-expanding conversion head 22 is smooth, the angle of the diffusion angle β is small (30 ° to 60 °), and the angle is steep when the system is vertically installed, so that no impurities are accumulated on the inner wall of the diameter-expanding conversion head 22. In addition, the small spread angle is also advantageous in that when the limestone slurry flows through the expanding conversion head 22, no vortex is formed at the pipe wall position of the expanding conversion head 22, thereby improving the stability of the limestone slurry flowing in the pipe. The ratio between the diameter of the inlet section and the diameter of the outlet section of the expanding conversion head 22 is less than or equal to 1/2, so that the flow speed of the slurry in the measuring section 21 can be reduced to be less than 1/4 of the flow speed of the slurry in the measuring section 21 close to the inlet of the slurry pipeline 1. Therefore, the flow is slow, the disturbance is small, the measurement result is more stable, the inner wall of the measurement section 21 of the limestone slurry density measurement system is processed by a finish machining process (the fineness is not lower than 3.2 mu m), the diameters of the sampling holes 43 on the high-pressure side and the low-pressure side are consistent, the flow velocity in the pipe is consistent, the influence of dynamic pressure errors on the measurement result caused by unequal flow velocity in the pipe at the positions of the sampling holes 43 on the high-pressure side and the low-pressure side can be eliminated, and the measurement accuracy is ensured.

Further, the caliber of the gas collector 49 is gradually reduced from the middle to both sides.

In particular, the diffusion angle α of the gas collector 49 is 60 °.

Further, the flange hole 45 and the back flushing port 46 are both provided with tapers; the caliber of the flange hole 45 is gradually reduced from the side communicated with the water seal section 44 to the side connected with the sensing diaphragm 33; the aperture of the backflush port 46 is gradually increased from the side communicated with the water seal section 44 to the side close to the gas collector 49.

Further, the slurry pipeline 1 is communicated with the measuring branch pipe 2 through a branch tee 25.

Referring to fig. 1-4, the working principle of the present invention is as follows:

firstly, intermittent operation under the accurate metering requirement;

when the density of the limestone slurry needs to be accurately measured, the limestone slurry density measuring system is in an intermittent operation mode through the PLC control system 5. Then, the second electric ball valve 24 is opened, and the first electric ball valve 11 is closed, so that the representative limestone slurry flows from the inlet of the measuring system through the branch three-way 25 and the diameter-expanding conversion head 22 into the measuring section 21, and fills the water seal mechanism 4 on the high-pressure side and the low-pressure side. Then, the slurry continuously flows to the diameter-reducing conversion head 23 and the middle section of the door-shaped measuring branch pipe 2, passes through the second electric ball valve 24, and then enters a downstream pipeline through the outlet of the measuring system to participate in other process links, or flows back to the circulating tank. After the continuous operation for 180 seconds, the first electric ball valve 11 is opened, the second electric ball valve 24 is closed, and the extracted limestone slurry directly enters a downstream process link without entering the measuring branch pipe 2; in the measuring section 21 of the measuring branch pipe 2, the limestone slurry does not flow, and the standing state is maintained for 600 seconds, and the operation of other equipment is not influenced. The bubbles contained in the slurry can continuously rise to the reducing conversion head 23 from the branch tee 25 under the action of gravity and gather at the bent pipe of the measuring branch pipe 2 in a door shape of the reducing conversion head 23, so that the content of the bubbles in the slurry on the measuring section 21 is reduced, and the measuring precision is improved. Meanwhile, the pressure remote transmitting type diaphragm differential pressure transmitter 3 with the capillary 31 registers the measurement value into the measurement result. Because the air bubbles in the measuring section 21 are eliminated, the measuring error caused by the air bubbles can be reduced, and the measured value is closer to the true value.

In particular, the intermittent measurement mode is adopted, so that the influence of bubbles in the medium and the influence of solid impurities are effectively eliminated.

Secondly, flushing the induction diaphragm 33;

after the measurement reading is completed, the flushing operation of the sensing diaphragm 33 can be started. First, the flushing solenoid valves 48 on the high pressure side and the low pressure side, respectively, are opened, so that flushing water can enter the connecting flange 42 of the water seal mechanism 4 from the flushing line 47 via the gas collector 49, flush the sensing diaphragm 33 and the sampling tube 41 of the differential pressure transmitter 3, and a water seal is formed in the water seal section 44 of the sampling pipe 41, the water seal section 44 is connected with the washing water, meanwhile, as the diameter (40 mm-50 mm) of the water seal section 44 is far larger than the diameter (10 mm-15 mm) of the sampling hole 43, flushing water is filled between the limestone slurry and the sensing diaphragm 33 of the differential pressure transmitter 3, so that the scale formation of the limestone slurry on the sensing diaphragm 33 can be reduced, the gas contained in the slurry can be reduced to enter the sampling pipe 41, and the time required for the solute in the slurry to enter the sampling tube 41 by diffusion is relatively long, to reduce the effect of limestone slurry adhering to the surface of sensing diaphragm 33 of differential pressure transmitter 3. After the flushing is continued for 120 seconds, the flushing electromagnetic valves 48 at the high pressure side and the low pressure side are respectively closed, and the flushing work is finished. At this point, the second electric ball valve 24 is opened again, the first electric ball valve 11 is closed, limestone slurry is drawn from the inlet of the measurement system into the measurement branch pipe 2, and the injection measurement section 21 starts sampling of the next cycle.

When the system is operated intermittently, the whole intermittent sampling and flushing time is controlled to be one cycle in 15 minutes. The whole measurement and the control action of each valve are controlled by a PLC control system 5. The time period of one cycle can be adjusted according to different limestone used on different sites and process requirements, but the shortest period is not less than 600 seconds.

Thirdly, continuously operating under the requirement of on-line measurement;

when a continuous measurement of the density parameter is required and the effects of bubbles and solid impurities in the slurry are negligible, a continuous mode of operation can be initiated in the system.

When the system is continuously operated, the limestone slurry density measuring system is in a continuous operation mode through the PLC control system 5. Then, the second electric ball valve 24 is opened, the first electric ball valve 11 is closed, all limestone slurry passes through the measuring section 21 of the measuring branch pipe 2, the differential pressure transmitter 3 continuously works, and differential pressure signals are transmitted into the PLC control system 5 and converted into density signals to be output.

The system is operated continuously, and the flushing and deslagging operation is carried out once per hour. After 3300 seconds of operation, the high-pressure side and low-pressure side flushing solenoid valves 48 are opened, and the flushing water enters the connecting flange 42 of the water seal mechanism 4 from the flushing pipeline 47 through the gas collector 49 and finally is discharged into the slurry through the sampling hole 43. The flush water continued to flush for 120 seconds and then the flush system was shut down. After 30 seconds, the first electric ball valve 11 is opened again, the second electric ball valve 24 is closed, and the flushing operation is restarted. After the flushing blowdown is continued for 150 seconds, the second motorized ball valve 24 is opened again, the first motorized ball valve 11 is closed, and the continuous measurement of the next cycle is started.

The above only is the embodiment of the present invention, not limiting the patent scope of the present invention, all the equivalent structures or equivalent processes that are used in the specification and the attached drawings or directly or indirectly applied to other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A limestone slurry density measuring system is characterized in that: comprises a slurry pipeline (1), a measuring branch pipe (2), a differential pressure transmitter (3) and a water seal mechanism (4); the measuring branch pipe (2) is in a shape of a Chinese character 'men', and two ends of the measuring branch pipe (2) are respectively communicated with the slurry pipeline (1); a measuring section (21) is arranged on one section of the measuring branch pipe (2) close to the inlet of the slurry pipeline (1); one ends of the two water sealing mechanisms (4) are respectively fixed with two ends of the differential pressure transmitter (3), and the other ends of the two water sealing mechanisms are respectively communicated with two ends of the measuring section (21); the differential pressure transmitter (3) is respectively provided with two capillary tubes (31), the tail end of each capillary tube (31) is respectively fixed with an installation flange (32), and the middle part of the end face of the tail end of the installation flange (32) is provided with an induction membrane (33); the water seal mechanism (4) comprises a sampling pipe (41) and a connecting flange (42) fixed with one end of the sampling pipe (41); a sampling hole (43) and a water seal section (44) which are communicated with each other are arranged in the sampling pipe (41), and the caliber of the tail end of the sampling hole (43) is gradually increased towards the water seal section (44); the connecting flange (42) is provided with a through flange hole (45) communicated with the water seal section (44); the sampling hole (43) communicates with the measuring section (21); the connecting flange (42) is fixed with the mounting flange (32), and the sensing diaphragm (33) covers the flange hole (45); the upper part of the connecting flange (42) is also provided with a backflushing opening (46); one end of the backflushing port (46) is communicated with the water seal section (44), and the other end of the backflushing port is communicated with a flushing pipeline (47).

2. The limestone slurry density measurement system of claim 1 wherein: also comprises a gas collector (49); one end of the gas collector (49) is communicated with the flushing pipeline (47), and the other end of the gas collector is arranged on the back flushing port (46).

3. The limestone slurry density measurement system of claim 2 wherein: the device also comprises a PLC control system (5); a first electric ball valve (11) is arranged on the slurry pipeline (1), and the first electric ball valve (11) is positioned between two connecting positions of the slurry pipeline (1) and the measuring branch pipe (2); a second electric ball valve (24) is arranged on one section of the measuring branch pipe (2) close to the outlet of the slurry pipeline (1); a flushing electromagnetic valve (48) is arranged on the flushing pipeline (47); the flushing electromagnetic valve (48) and the back flushing port (46) are respectively positioned at two sides of the gas collector (49); the PLC control system (5) is in electric signal connection with the differential pressure transmitter (3); the PLC control system (5) is respectively in electric signal connection with the first electric ball valve (11), the second electric ball valve (24) and the flushing electromagnetic valve (48) and respectively controls the opening and closing of the first electric ball valve (11), the second electric ball valve (24) and the flushing electromagnetic valve (48).

4. The limestone slurry density measurement system of claim 2 wherein: the measuring section (21) is provided with an expanding conversion head (22) and a reducing conversion head (23); the diameter-expanding conversion head (22) is positioned at one end of the measuring section (21) close to the inlet of the slurry pipeline (1), and the caliber of the diameter-expanding conversion head (22) is gradually increased towards the measuring section (21); the reducing conversion head (23) is positioned at the other end of the measuring section (21), and the caliber of the reducing conversion head (23) is gradually increased towards the measuring section (21).

5. The limestone slurry density measurement system of claim 2 wherein: the caliber of the gas collector (49) is gradually reduced from the middle to two sides.

6. The limestone slurry density measurement system of claim 2 wherein: the flange hole (45) and the back flushing port (46) are provided with tapers; the caliber of the flange hole (45) is gradually reduced from one side communicated with the water seal section (44) to the side connected with the induction membrane (33); the caliber of the backflushing opening (46) is gradually increased from one side communicated with the water seal section (44) to one side close to the gas collector (49).

7. The limestone slurry density measurement system of claim 1 wherein: the slurry pipeline (1) is communicated with the measuring branch pipe (2) through a branch tee joint (25).