JP2014048212A - Capillary tube bubble detection device and bubble detection method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably detect bubbles in a capillary tube with a simple configuration.SOLUTION: A capillary tube bubble detection device 1 includes: a capillary tube 2 which has both ends connected to a process pipe 21 and has two spiral-shaped portions into which parts having a prescribed length from both ends are spirally bent; a differential pressure measurer 3 which is provided in a position interposed between the two spiral-shaped portions and measures a differential pressure between both sides of the capillary tube 2; a pair of pressure measurers 4 provided so that at least one of the two spiral-shaped portions is held therebetween; and a control unit 5 which determines the existence of bubbles in the capillary tube 2 in the case that pressures measured by the pair of pressure measurers 4 show a response lag or a decay.

Description

  The present invention relates to a capillary tube bubble detection device that detects bubbles in a capillary tube that measures the flow rate of a process pipe, and a bubble detection method thereof.

  As an apparatus for measuring the flow rate of a process pipe in a power plant such as a nuclear power plant, there is one using a capillary tube and a differential pressure measuring device. The capillary tube is provided with both ends connected to two longitudinal positions of the process pipe to be measured, and the differential pressure measuring device measures the flow rate by measuring the differential pressure of the liquid medium transmitted through the capillary tube.

  The capillary tube is filled with water by water filling during measurement. Therefore, there is a possibility that an abnormality occurs in pressure transmission mainly due to the mixing of bubbles into the capillary tube during water filling, and the differential pressure type measuring instrument may show an abnormal value.

  Therefore, a technology has been developed to detect the clogging of the capillary tube by measuring the differential pressure and static pressure of the capillary tube, obtaining the average or dispersion of the ratio of the differential pressure to static pressure vibration, and comparing it with a threshold value. (For example, refer to Patent Document 1).

  In addition, in a dispensing device that presses liquid with a pump and injects it with a nozzle, two pressure sensors are provided in the path of the liquid to detect the time delay of the two pressure sensors and a decrease in the rate of change to generate bubbles. A technique for determining has been developed (see, for example, Patent Document 2).

JP 2009-53083 A JP-A-10-227799

  The technique described in Patent Document 1 described above detects clogging using a differential pressure, but since the differential pressure changes depending on the flow rate and flow rate, calculation and threshold values for clogging determination at various flow rates and flow rates. It is difficult to set up.

  Moreover, the technique described in Patent Document 2 described above is a technique applied to a dispensing apparatus, which requires a pressure generating source such as a pump and allows liquid to flow in one direction. Therefore, the configuration is different from the bubble detection in the capillary tube in which the liquid medium vibrates and flows in both directions in the tube according to the pressure of the process piping.

  Therefore, an object of the present invention is to provide a capillary tube bubble detection device that can detect bubbles in a capillary tube with a simple configuration.

  In order to achieve the above object, a capillary tube bubble detection device according to the present invention includes a capillary tube having two spiral-shaped portions each having a spirally curved predetermined distance from both ends connected to a process pipe. The capillary tube is provided at a position sandwiched between two spiral-shaped portions, and measures a differential pressure on both sides of the capillary tube and sandwiches at least one of the two spiral-shaped portions of the capillary tube. And a control device for determining that bubbles are mixed in the capillary tube when the pressure measured by the pair of pressure measuring devices shows a delay in response or attenuation. It is characterized by.

  Furthermore, in order to achieve the above object, the capillary tube bubble detection method of the present invention includes a capillary tube having two spiral-shaped portions that are connected at both ends to a process pipe and have a predetermined distance from the both ends spirally curved. A step of measuring the pressure at a pair of positions sandwiching at least one of the two spiral-shaped portions, and if the pair of pressures show a delay in response or attenuation, bubbles are mixed in the capillary tube. And a step of determining.

  According to the present invention, bubbles in the capillary tube can be detected stably with a simple configuration.

1 is a schematic configuration diagram of a capillary tube bubble detection device according to a first embodiment of the present invention. The functional block diagram of the capillary tube bubble detection apparatus which concerns on the 1st Embodiment of this invention. The schematic block diagram of the capillary tube bubble detection apparatus which concerns on the 2nd Embodiment of this invention. The schematic block diagram of the capillary tube bubble detection apparatus which concerns on the 3rd Embodiment of this invention.

  Embodiments of the present invention will be described below.

(First embodiment)
(Constitution)
Hereinafter, a capillary tube bubble detection device according to a first embodiment of the present invention will be described with reference to FIG. 1 and FIG. FIG. 1 is a schematic configuration diagram of a capillary tube bubble detection device according to a first embodiment of the present invention.

  The capillary tube bubble detection device 1 includes a capillary tube 2, a differential pressure measuring device 3, pressure measuring devices 4 a and 4 b, a control device 5, a vibration device 6, and an alarm device 7.

  The process pipe 21 is a pipe through which a fluid flows. The restrictor flow meter 22 is provided with an orifice or the like (not shown) therein, and generates a differential pressure upstream and downstream. The pressure guiding pipes 23a and 23b are connected to the process pipes 2 upstream and downstream of the orifice, respectively, and transmit the pressure upstream and downstream of the orifice via the internal liquid medium.

  Both ends of the capillary tube 2 are connected to two pressure guides 23a and 23b by unions (joints) via instrument inlet valves. Alternatively, both ends of the capillary tube 2 may be directly connected to the process pipe 21. Further, in order to separate the liquid medium in the process pipe 21 and the pressure guide 23a, 23b and the liquid medium in the capillary tube 2, the process pipe 21 and the pressure guide 23a, 23b are connected via a film capable of transmitting pressure. It is good.

  The capillary tube 2 has a spiral-shaped portion that is spirally curved at a predetermined distance from both ends. In the capillary tube 2, a differential pressure measuring device 3 is provided at a position between the two spiral-shaped portions. The differential pressure measuring device 3 measures the differential pressure from both sides of the capillary tube 2.

  A pair of pressure measuring devices 4 a and 4 b are provided so as to sandwich at least one of the two spiral-shaped portions of the capillary tube 2. Further, the vibration device 6 is provided on the side of the capillary tube 2 where the pressure measuring devices 4a and 4b are provided.

  The differential pressure measuring device 3 transmits the measured differential pressure to a flow rate measuring device (not shown), and the flow rate measuring device calculates the flow rate and flow velocity of the fluid from the measured differential pressure. The pressure measuring devices 4 a and 4 b can transmit the measured pressure to the control device 5. The control device 5 can transmit a vibration command for causing the vibration device 6 to vibrate, and can generate an alarm using the alarm device 7.

  Further, as shown in FIG. 1, a pressure equalizing valve for uniformly adjusting the pressures on both sides of the differential pressure measuring device 3, a drain valve for introducing and deriving water of the liquid medium when filling with water and draining, a process pipe 21 and a pressure guiding pipe 23a , 23b can be appropriately provided with a detection source valve for closing the flow of the liquid medium in the vicinity of the connecting portion. In addition, as shown in FIG. 1, not only the pressure measuring devices 4a and 4b and the vibration device 6 are provided in one of the two spiral-shaped portions, but also a configuration in which both are provided in the two spiral-shaped portions.

(Function)
The operation of the first embodiment of the present invention will be described below.

  When measuring the flow rate of the fluid using the capillary tube 2, the capillary tubes 2 and 23 are filled with water as a pressure transmission liquid medium. The differential pressure generated upstream and downstream by the restrictor flow meter 22 is transmitted to both ends of the capillary tube 2 via the pressure guiding tubes 23a and 23b, respectively, and after minute pulsations are suppressed in the helical shape portion of the capillary tube 2, The differential pressure is measured by the differential pressure measuring device 3.

  Since the helically shaped portion of the capillary tube 2 is usually a small diameter of about 1 mm in diameter and is curved in a helical shape, bubbles may be mixed in mainly during the water filling described above. Hereinafter, the bubble detection method and the bubble removal method will be described.

  The liquid medium in the capillary tube 2 vibrates and circulates in both directions. The pressure measuring devices 4a and 4b each measure the pressure at the installation location and transmit it to the control device 5. The control device 5 receives the pressure measured from the pressure measuring devices 4a and 4b, and detects a response delay or attenuation between the two pressures.

  When there are no bubbles in the capillary tube 2, the pressure is normally transmitted through the liquid medium, so that there is almost no response delay or attenuation between the two pressures. When bubbles are present in the capillary tube 2, pressure is delayed or attenuated due to the bubbles, and a response delay or attenuation between the two pressures occurs.

  The control device 5 detects the response delay by comparing the time difference between the rise and peak of the two pressures with a predetermined threshold, and detects the attenuation by comparing the peak value and the integral value of the two pressures with the predetermined threshold. Since the liquid medium in the capillary tube 2 vibrates and flows in both directions, it is possible to detect response delay or attenuation in both directions.

  Here, since the pressure of the process pipe 21 is transmitted from the process pipe 21 to the differential pressure measuring device 3, when bubbles are present in the capillary tube 2, the direction from the process pipe 21 to the differential pressure measuring device 3. In many cases, response delay or attenuation occurs. Therefore, it is desirable to detect the attenuation or delay of the pressure in the direction from the process pipe 21 to the differential pressure measuring device 3 out of the response delay or attenuation in both directions.

  Furthermore, since a slight response delay or attenuation may occur due to pulsation suppression in the spiral shape portion of the capillary tube 2, it is desirable to set a threshold value for response delay and attenuation detection by subtracting the pulsation suppression amount.

  FIG. 2 is a functional block diagram of the capillary tube bubble detection device according to the first embodiment of the present invention. The control device 5 includes a data storage unit 41, a data processing unit 42, a data determination unit 43, and a command unit 44. The two pressure measuring devices 4 a and 4 b transmit the measured pressure to the control device 5. The control device 5 stores the received pressure in the data storage unit 41 and transmits it to the data processing unit 42.

  The data processing unit 42 detects the attenuation or response delay between the measured pressures of the two pressure measuring devices 4a and 4b. The data determination unit 43 receives the detection result from the data processing unit and determines bubbles. It can be compared with a threshold. When the data determination unit 43 detects a bubble, the command unit 44 generates an alarm in the alarm device 7 and vibrates the vibration device 6 that is a bubble removal device.

  After the vibration device 6 is vibrated, the pressure attenuation or response delay measured by the two pressure measuring devices 4a and 4b is detected again. If no attenuation or response delay is detected, the alarm generation of the alarm device 7 and The vibration of the vibration device 6 is stopped.

(effect)
According to the first embodiment of the present invention, it is possible to detect and remove bubbles in the capillary tube 2 by detecting bubbles in the control device 5 and operating the vibration device 6 to vibrate the capillary tube 2. it can.

  Even when not only air bubbles but also the capillary tube 2 is blocked or foreign matter that obstructs the flow is mixed, the foreign matter can be detected by detecting the attenuation or response delay between the two pressures.

(Second Embodiment)
(Constitution)
Hereinafter, a capillary tube bubble detection device according to a second embodiment of the present invention will be described with reference to FIG. The same parts as those of the capillary tube bubble detection device according to the first embodiment are denoted by the same reference numerals, and description of the same configuration is omitted.

  FIG. 3 is a schematic configuration diagram of a capillary tube bubble detection device according to a second embodiment of the present invention. The second embodiment is different from the first embodiment in that stop valves 8a and 8b, circulation valves 9a and 9b, and a circulation pump 10 are provided in place of the vibration device 6. Further, a circulation path 31 is provided at both ends of the spiral-shaped portion so as to branch off from the capillary rib 2.

  The stop valves 8a and 8b are provided upstream and downstream of the connection part of the circulation path 31 of the spiral portion of the capillary tube 2 so that the flow of the liquid medium can be stopped by a closing operation. The circulation valves 9a and 9b are provided in the circulation path 31, and water can be circulated in the circulation path 31 by an opening operation.

  Furthermore, the circulation pump 10 operates in response to a command from the control device 5 and can circulate water in a circulation loop including the circulation path 31 and the capillary rib 2.

(Function)
The operation of the second embodiment of the present invention will be described below.

  Since the bubble detection method in the control device 5 is the same as that in the first embodiment, description thereof is omitted. During normal operation, the stop valves 8a and 8b are opened and the circulation valves 9a and 9b are closed to transmit the pressure of the liquid medium in the capillary tube 2.

  When air bubbles are detected in the control device 5, the control device 5 closes the stop valves 8a and 8b and opens the circulation valves 9a and 9b. Furthermore, the control device 5 transmits a command for operating the circulation pump 10.

  The circulation pump 10 operates in response to a command from the control device 5 and circulates the liquid medium in the circulation path 31 and the capillary rib 2.

  The bubbles in the capillary rib 2 move to the circulation path 31 side by the circulation of the liquid medium of the circulation pump 10, and the bubbles in the capillary rib 2 are removed. In the circulation path 31, the removed bubbles can be extracted to the outside by appropriately providing an air vent valve or the like.

(effect)
According to the second embodiment of the present invention, the control device 5 detects air bubbles, further operates the stop valves 8a and 8b and the circulation valves 9a and 9b to form a circulation loop, and circulates water by the circulation pump 10. By doing so, the bubbles in the capillary rib 2 can be detected and removed.

(Third embodiment)
(Constitution)
Hereinafter, a capillary tube bubble detection device according to a third embodiment of the present invention will be described with reference to FIG. The same parts as those of the capillary tube bubble detection device according to the first embodiment are denoted by the same reference numerals, and description of the same configuration is omitted.

  FIG. 4 is a schematic configuration diagram of a capillary tube bubble detection device according to a third embodiment of the present invention. The third embodiment is different from the first embodiment in that an insertion device 11 is provided instead of the vibration device 6.

The insertion device 11 is provided so that a thin rod having a smaller diameter than the capillary tube 2 having flexibility can be inserted into the capillary tube 2 (operation).
The operation of the third embodiment of the present invention will be described below.

  Since the bubble detection method in the control device 5 is the same as that in the first embodiment, description thereof is omitted. When air bubbles are detected in the control device 5, the control device 5 transmits a thin rod insertion command to the insertion device 11. When the insertion device 11 receives the insertion command, the insertion device 11 inserts a thin rod into the spiral shaped portion of the capillary tube 2. The internal bubbles are pushed out and removed by the thin rod.

(effect)
According to the third embodiment of the present invention, the control device 5 detects air bubbles, and the insertion device 11 inserts a thin rod into the capillary tube 2 to detect and remove air bubbles in the capillary tube 2. Can do.

DESCRIPTION OF SYMBOLS 1 ... Capillary tube bubble detection apparatus 2 ... Capillary tube 3 ... Differential pressure measuring instrument 4 ... Pressure measuring instrument 5 ... Control apparatus 6 ... Vibration apparatus 7 ... Alarm apparatus 8a, 8b ... Stop valves 9a, 9b ... Circulation valve 10 ... Circulation pump 11 ... Insertion device 21 ... Process piping 22 ... Restriction flowmeters 23a, 23b ... Pressure guiding pipe 31 ... -Circulation path 41 ... Data storage 42 ... Data processing unit 43 ... Data determination unit 44 ... Command unit

Claims (10)

A capillary tube having two spiral-shaped portions each having both ends connected to the process piping and spirally curved at a predetermined distance from both ends;
Of the capillary tube, a differential pressure measuring device provided at a position sandwiched between the two spiral-shaped portions and measuring the differential pressure on both sides of the capillary tube;
A pair of pressure measuring devices provided so as to sandwich at least one of the two spiral-shaped portions of the capillary tube;
A capillary tube bubble detection device comprising: a control device that determines that bubbles are mixed in the capillary tube when the pressure measured by the pair of pressure measuring devices indicates a response delay or attenuation. .   The capillary tube bubble detection device according to claim 1, further comprising an alarm device that issues an alarm when bubbles are detected in the control device.   The capillary tube bubble detection device according to claim 1, further comprising a bubble removal device that removes bubbles when bubbles are detected in the control device.   4. The capillary tube bubble detection device according to claim 3, wherein the bubble removal device is a vibration device that vibrates the capillary tube. The bubble removing device includes a circulation path branched from the capillary tube;
A circulation pump provided in the circulation path,
The capillary tube bubble detection device according to claim 3, wherein a circulation loop that circulates between the capillary tube and the circulation path is formed, and the liquid medium is circulated by the circulation pump in the circulation loop.   4. The capillary tube bubble detection device according to claim 3, wherein the bubble removal device is an insertion device that inserts a flexible thin rod into the capillary tube.   The capillary tube bubble detection device according to any one of claims 3 to 6, wherein the bubble removal device stops operation when bubble detection is not performed in the control device. The control device includes:
The capillary according to any one of claims 1 to 7, wherein a response delay or attenuation is detected using a threshold value set by subtracting a pulsation suppression component by the spiral-shaped portion. Tube bubble detection device.   The capillary tube bubble detection according to any one of claims 1 to 8, wherein the control device determines a response delay or an attenuation in a direction from the process pipe to the differential pressure transmitter. apparatus. At a pair of positions sandwiching at least one of the two spiral-shaped portions of the capillary tube having two spiral-shaped portions that are connected at both ends to the process piping and spirally curved at a predetermined distance from both ends. Measuring the pressure;
And a step of determining that bubbles are mixed in the capillary tube when the pair of pressures show a response delay or attenuation.

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