JP2009068997A - Flow sensor abnormality detection method and deaeration apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily detect abnormalities in a flow sensor in a liquid treatment apparatus. <P>SOLUTION: The flow sensor abnormality detection method in a water treatment apparatus which comprises a treatment tank 2, a feeding first pump 20, a draining second pump 26, a flow sensor 22 for detecting a liquid supply flow, and a liquid level sensor 16A and performs control to be a set liquid level on the basis of a signal from the liquid level sensor 16A stops the operation of the second pump 26 when a flow detection signal is determined to be under set value and determines that the flow sensor 22 is abnormal when a liquid level detection signal increases by a predetermined amount within a set period of time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an abnormality detection method for a flow sensor applied to a liquid processing apparatus such as a vacuum type degassing apparatus for degassing dissolved gas in a liquid, and a degassing apparatus.

  2. Description of the Related Art Vacuum deaerators that reduce dissolved gas, for example, dissolved oxygen, in a liquid to be treated are widely used for applications such as water supply, cleaning, and food processing. As an example in water supply applications, thermal equipment such as steam boilers and exhaust gas boilers may corrode in heat transfer tubes due to dissolved oxygen in the feed water and may be damaged in a short period of time. In addition, buildings such as buildings and condominiums may corrode in the water supply piping due to dissolved oxygen in the water supply, resulting in red water. For this reason, in the said thermal equipment or the said building, installing the said deaeration apparatus in a water supply system and reducing dissolved oxygen in water supply are performed.

  As disclosed in Patent Document 1, the deaeration device first supplies a liquid to be processed to a nozzle provided in an upper part of the processing tank by a pressurizing pump, and then supplies the liquid to be processed from the upper part in the processing tank. It spouts toward the bottom. Then, by vacuuming the inside of the processing tank, the dissolved gas is degassed from the ejected droplets, and then stored as a processing liquid, and the processing liquid is discharged from the processing tank by a liquid feed pump. Device.

JP-A-8-108005

  By the way, in the deaeration device, in order to perform efficient deaeration, it is important to maintain the ejection flow rate from the nozzle and the liquid level in the processing tank within a predetermined range. The ejection flow rate from the nozzle affects the droplet size of the liquid to be processed, and the smaller the ejection flow rate, the larger the droplet and the lower the deaeration efficiency. On the other hand, the liquid level in the treatment tank affects the deaeration time of the liquid to be treated. The higher the liquid level, the shorter the deaeration time and the lower the deaeration efficiency. Therefore, in the degassing apparatus, the supply flow rate of the liquid to be processed is adjusted to a preset reference processing flow rate so that the size of the droplets from the nozzle is constant, and the liquid level in the processing tank is also set. Is adjusted to the reference processing flow rate to maintain a predetermined degassing efficiency.

  Adjustment of the supply flow rate of the liquid to be treated is usually performed using a flow sensor and a manual valve provided on the downstream side of the pressurizing pump. Specifically, in consideration of the viscosity of the liquid to be processed and the pressure loss at the nozzle, the pressure pump has a high operating pressure in advance so that the supply flow rate is higher than the reference processing flow rate. Is set. Then, the supply flow rate is measured by the flow rate sensor during trial operation or maintenance, and the opening of the manual valve is reduced so that the measured value matches the reference processing flow rate.

  On the other hand, the adjustment of the discharge flow rate of the processing liquid is usually performed using a flow sensor and a manual valve provided on the downstream side of the liquid feed pump, similarly to the adjustment of the supply flow rate of the liquid to be processed. Specifically, in consideration of the viscosity of the processing liquid, the degree of vacuum in the processing tank, and the like, the liquid feed pump has a high operating pressure in advance so that the discharge flow rate is higher than the reference processing flow rate. Is set. Then, during trial operation, maintenance, etc., the discharge flow rate is measured by the flow rate sensor, and the opening of the manual valve is reduced so that the measured value matches the reference processing flow rate.

As described above, the conventional degassing apparatus has a configuration in which the supply flow rate of the liquid to be processed and the discharge flow rate of the treatment liquid are manually adjusted. Therefore, the operation is extremely complicated, and performance maintenance is not easy. . In the deaeration device, the operating pressures of the two pumps are set to be high and the flow rate is reduced, so that the power consumption of both the pumps is large and the running cost is increased.

  In view of the above circumstances, the applicant of the present invention facilitates the adjustment work of the supply flow rate of the liquid to be processed, reduces the power consumption of the pump on the supply side, and supplies the supply flow rate of the liquid to be processed and the treatment liquid. Japanese Patent Application No. 2006-86837 filed a deaeration device that facilitates the adjustment of the discharge flow rate and can simultaneously reduce the power consumption of both the supply-side and discharge-side pumps. This deaeration device is a deaeration device comprising a nozzle that ejects a liquid to be processed into a processing tank and a vacuum suction means in the processing tank, and a first pump that supplies the liquid to be processed to the nozzle A second pump for discharging the processing liquid from the processing tank, a first flow sensor for detecting the supply flow rate of the liquid to be processed, a liquid level sensor for detecting the liquid level in the processing tank, and the first pump Based on the flow rate detection signal from the first inverter that controls the rotation speed of the second pump according to the output frequency, the second inverter that controls the rotation speed of the second pump according to the output frequency, A control unit that outputs a command signal to the first inverter and outputs a command signal to the second inverter based on a liquid level detection signal from the liquid level sensor.

  The problem to be solved by the present invention is to easily detect an abnormality of a flow sensor in a liquid processing apparatus such as a degassing apparatus of Japanese Patent Application No. 2006-86837 that has been filed.

  This invention was made in order to solve the said subject, and invention of Claim 1 is a processing tank which stores a to-be-processed liquid, The pump which supplies a to-be-processed liquid to this processing tank, The said process A liquid level sensor for detecting a liquid level in the processing tank, and a liquid level sensor for detecting a liquid level in the processing tank. An abnormality detection method for a flow sensor in a liquid processing apparatus for controlling a liquid level in the processing tank to a set liquid level based on a signal, wherein a first determination is made as to whether a flow detection signal of the flow sensor is equal to or less than a set value. A step, a second step of stopping the operation of the drainage means when it is determined that the value is less than a set value in the first step, and a liquid level detection signal of the liquid level sensor within a set time after the second step. When there is a predetermined increase, the flow rate sensor Is characterized in that performs a third step of determining as abnormal.

  According to the first aspect of the present invention, it is possible to detect an abnormality of the flow rate sensor based on a change in a liquid level signal by the liquid level sensor, and without using a separate sensor such as a pressure detector. It is possible to detect an abnormality in the flow sensor.

  The invention described in claim 2 is a deaeration device comprising a nozzle for ejecting a liquid to be treated into the treatment tank and a vacuum suction means in the treatment tank, wherein the liquid to be treated is supplied to the nozzle. One pump, a flow sensor for detecting the supply flow rate of the liquid to be processed, a first inverter for controlling the rotation speed of the first pump according to an output frequency, and a second pump for discharging the processing liquid from the processing tank And a liquid level sensor that detects a liquid level in the processing tank, a second inverter that controls the rotation speed of the second pump according to an output frequency, and a flow rate detection signal from the flow rate sensor, A control unit that outputs a command signal to the first inverter and outputs a command signal to the second inverter based on a liquid level detection signal from the liquid level sensor, and the control unit includes: Flow rate detection signal is less than the set value A first step for determining whether or not, a second step for stopping the operation of the second pump when it is determined that the set value or less is determined in the first step, and the liquid level within a set time after the second step. And a third step of determining that the flow sensor is abnormal when the liquid level detection signal of the sensor has a predetermined increase.

  According to the second aspect of the present invention, it is possible to detect an abnormality of the flow rate sensor based on a change in the liquid level signal by the liquid level sensor, and without using a separate sensor such as a pressure detector. It is possible to detect an abnormality in the flow sensor.

  According to a third aspect of the present invention, in the second aspect, when the control unit determines that an abnormality has occurred in the third step, the operation frequency averaged over a predetermined time immediately before the flow sensor is determined to be abnormal. To control the first pump.

  According to the third aspect of the present invention, in addition to the effect of the second aspect of the invention, the operation of the deaeration device is continued in a state where the flow rate sensor is close to normal despite the abnormality of the flow rate sensor. There is an effect that can be done.

  According to the present invention, it is possible to easily detect an abnormality in the flow sensor without separately providing a sensor such as a pressure detector.

  Next, an embodiment of the present invention will be described. The abnormality detection method of the flow sensor according to the embodiment of the present invention is preferably implemented in a liquid processing apparatus such as a tower type deaeration apparatus.

(Embodiment 1)
The first embodiment will be specifically described. In the first embodiment, a processing tank for storing a processing liquid, a pump for supplying the processing liquid to the processing tank, a drain means for discharging the processing liquid from the processing tank, and a supply flow rate of the processing liquid And a liquid level sensor that detects the liquid level in the processing tank, and controls the liquid level in the processing tank to a set liquid level based on a liquid level detection signal of the liquid level sensor. A method for detecting an abnormality of a flow sensor in a liquid processing apparatus, comprising: a first step for determining whether or not a flow rate detection signal of the flow sensor is equal to or less than a set value; A second step for stopping the operation of the liquid means, and a third step for determining that the flow rate sensor is abnormal when the liquid level detection signal of the liquid level sensor has a predetermined increase within a set time after the second step. A flow characterized by An abnormality detecting method of the sensor.

  In Embodiment 1 of the present invention, the abnormality of the flow sensor is detected while performing normal liquid level control. The normal liquid level control includes a liquid level control for controlling the liquid level in the processing tank to a set liquid level based on at least a liquid level detection signal of the liquid level sensor. In addition to the liquid level control, the flow rate sensor Liquid supply amount control for controlling the rotation speed of the pump based on the flow rate detection signal can be included. The set liquid level control can be performed by using the drainage means and / or the pump, that is, by using either one or both of the drainage means and the pump.

  The abnormality detection of the flow rate sensor is performed as follows. First, in the first step, it is determined whether the flow rate detection signal of the flow rate sensor is equal to or less than a set value. The set value of the flow rate detection signal is set to a value exceeding zero, but may be set to zero.

  Next, when it is determined in the first step that the value is not more than the set value, the operation of the draining means is stopped. In this step, if necessary, before the operation of the draining means is stopped, control for lowering the liquid level in the processing tank by the operation of the draining means is added. This liquid level lowering control is a control for preventing the liquid level from rising more than necessary after the third step.

In the third step following the second step, the pump is operated, and it is monitored whether there is a predetermined increase in the liquid level detection signal of the liquid level sensor within a set time after the second step, The flow sensor determines that there is an abnormality when there is a predetermined increase. The predetermined increase is preferably such that the increase rate of the liquid level detection signal is equal to or higher than a set value. While monitoring whether the predetermined increase is present or not, the same determination as in S2 is performed, and if it is determined for a set time that the flow rate is not less than or equal to the set value, it is not determined that the flow rate sensor is abnormal.

  Thus, by setting the abnormality determination condition such that the increasing speed of the liquid level detection signal is equal to or higher than the set value, it is possible to determine whether the liquid supply system from the processing tank is abnormal or the flow sensor is abnormal.

  Here, components constituting the first embodiment of the present invention will be described. The treatment tank is not limited to a specific structure as long as some kind of treatment is performed on the liquid to be treated. This processing tank is a processing tank that performs deaeration if the apparatus to which the first embodiment is applied is a tower-type degassing apparatus.

  When the pump includes a liquid supply amount control for controlling the rotation speed of the pump based on the flow rate detection signal of the flow sensor, the pump is a pump capable of controlling the rotation speed, and preferably the rotation speed is controlled by an inverter. And This pump may be an ON-OFF type.

  The drainage means is a means for discharging the liquid from the treatment tank, and is preferably a pump, but can be an on-off valve if drainage control is possible by opening and closing the valve. Here, “drainage” not only means discharging in a liquid state, but also means discharging in a gas state like a steam boiler can.

  The flow sensor is not limited to a specific flow sensor as long as it can detect the amount of liquid supplied to the treatment tank. The flow sensor can be referred to as a flow meter. Further, the detection signal of the flow rate sensor is not limited to that used for controlling the rotation speed of the pump, and can be used only for simple flow rate detection and notification, for example.

  The liquid level sensor is preferably a transmission output type liquid level sensor (which may be referred to as an analog output type liquid level sensor), but may be a contact output type liquid level sensor. The transmission output type liquid level sensor has a different configuration depending on whether the liquid in the processing tank is conductive or non-conductive, and whether the material of the container of the processing tank is metal. 1, the transmission output type liquid level sensor of any configuration is applicable. The transmission output type liquid level detection means is preferably a capacitance type level sensor, but is not limited to this, and is a pressure sensor for detecting the water head pressure to measure the liquid level, or a float type level sensor. A water level sensor, an ultrasonic water level sensor, or the like can be used.

  The contact output type liquid level detection means is a level sensor that detects the specific liquid level based on a change in the output state at the specific liquid level in the processing tank, and preferably an electrode type that detects the specific liquid level. Although it is a level switch, it can be a float type level sensor.

  The first embodiment of the present invention is typically applied to the deaeration device of the second embodiment.

(Embodiment 2)
The second embodiment is a deaeration device having a nozzle for ejecting a liquid to be processed into a processing tank and a vacuum suction means in the processing tank, and a first pump for supplying the liquid to be processed to the nozzle A flow rate sensor that detects the supply flow rate of the liquid to be processed, a first inverter that controls the rotation speed of the first pump according to an output frequency, a second pump that discharges the processing liquid from the processing tank, Based on the liquid level sensor for detecting the liquid level in the processing tank, the second inverter for controlling the rotation speed of the second pump according to the output frequency, and the flow rate detection signal from the flow rate sensor, the first A control unit that outputs a command signal to the inverter and outputs a command signal to the second inverter based on a liquid level detection signal from the liquid level sensor, wherein the control unit detects a flow rate of the flow rate sensor. Whether the signal is below the set value A first step for determining whether or not the set value or less is determined in the first step, the second pump is operated to lower the liquid level in the treatment tank, and then the second pump is operated. Performing a second step of stopping and a third step of determining that the flow sensor is abnormal when the liquid level detection signal of the liquid level sensor has a predetermined increase within a set time after the second step. It is the deaeration device characterized.

  In the second embodiment, the following normal liquid level control is performed. The first pump is operated by the first inverter. A flow rate detection signal from the first flow rate sensor is fed back to the first inverter as a command signal via the control unit. The rotation speed of the first pump is controlled according to the output frequency of the first inverter, and the supply flow rate of the liquid to be processed is operated so as to coincide with a preset reference processing flow rate. On the other hand, the operation of the second pump is performed by the second inverter. A liquid level detection signal from the liquid level sensor is fed back to the second inverter as a command signal through the control unit. The rotation speed of the second pump is controlled according to the output frequency of the second inverter, and the liquid level of the processing liquid in the processing tank is operated so as to match a preset reference liquid level. The Accordingly, the operating pressure of the first pump is automatically adjusted so that the size of the droplets from the nozzle is constant, and the deaeration time in the processing tank is constant, The operating pressure of the second pump is automatically adjusted, and the power consumption of both pumps is simultaneously reduced while maintaining a predetermined deaeration efficiency.

  Then, abnormality detection control of the flow sensor is performed as in the first embodiment. The difference from the first embodiment is that in the second step, the second pump is operated (driven) before the second pump is stopped, and control is performed to lower the liquid level in the processing tank. Since only the points are the same, the description is omitted.

  Next, components of the second embodiment will be described. In the second embodiment, the components other than the control unit are basically the same as those in the first embodiment, and the description thereof is omitted.

  The control unit executes, as part of the control procedure, a first control procedure for executing the normal liquid level control, an abnormality detection of the flow sensor, and a backup control of the first pump when an abnormality is determined. The second control procedure is stored. And in addition to these control procedures, the 3rd control procedure which calculates | requires the average value of the operating frequency used for backup control of said 1st pump can be included. This third control procedure can be included in the second control procedure.

  In the third control procedure, it is preferable that the first flow rate indicates whether the flow rate detected by the flow rate sensor is within a certain range with respect to a reference process flow rate (which can be referred to as a target flow rate) by the first pump. A condition, a second condition that a flow rate detection signal from the flow sensor is used to control the first pump, and a set time (time for the pump operation to stabilize) from the start of the first pump operation. When the third condition of being later is satisfied at the same time, the operating frequency is sampled every predetermined time. Then, an average operating frequency is obtained by averaging the predetermined number of samples.

Furthermore, a first abnormality determination program for determining whether or not the transmission output type liquid level sensor is normal can be included as a control procedure of the control unit. The control procedure may further include a second abnormality determination program for determining whether or not the contact output type liquid level sensor used for determining the abnormality of the transmission output type liquid level sensor is normal. In the second embodiment, preferably, the transmission output type liquid level sensor is determined to be normal by the first abnormality determination program, and the contact output type liquid level sensor is determined to be normal by the second abnormality determination program. When it is determined, the result of the abnormality detection of the flow sensor is determined to be correct.

  The first abnormality determination program may be a method described in JP 2000-55712 A, but is not limited to this. The second abnormality determination program may be a method described in Japanese Patent Application Laid-Open No. 2000-55712 and Japanese Patent Publication No. 4-8732, but is not limited thereto.

(Configuration of Example 1)
Embodiment 1 of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of a deaeration apparatus according to the first embodiment, FIG. 2 is a flowchart for explaining a main part control procedure of the first embodiment, and FIG. 3 is a flowchart of the first embodiment. It is a flowchart figure explaining another principal part control procedure.

  The deaeration apparatus according to the first embodiment is installed in a water supply system such as a thermal apparatus such as a steam boiler or an exhaust gas boiler, or a building such as a building or an apartment, and is used for the purpose of preventing corrosion of heat transfer pipes and water supply pipes. It is applied when reducing the dissolved oxygen. In FIG. 1, the deaeration device 1 mainly includes a processing tank 2, a nozzle 3, and a vacuum suction means 4.

  The treatment tank 2 has a cylindrical body portion 5 that is erected vertically, and is integrated by sealing the lower end opening with the bottom plate 6 and the upper end opening with the top plate 7. A closed container is formed. Here, the said processing tank 2 is normally formed using stainless steel (for example, SUS304 etc.) from a viewpoint of ensuring pressure | voltage resistance, heat resistance, and corrosion resistance.

  The bottom plate 6 is provided with a treated water supply port 8 and a treated water discharge port 9, respectively. The supply port 8 is located at the center of the bottom plate 6, that is, substantially at the center of the bottom plate 6. Is provided. On the other hand, the top plate 7 is provided with an exhaust port 10, to which the vacuum suction means 4 is connected. Details of the vacuum suction means 4 will be described later.

  In the processing tank 2, one end side of a supply pipe 11 extending upward is liquid-tightly connected to the supply port 8, and the nozzle 3 is connected to the other end side of the supply pipe 11. Yes. That is, the nozzle 3 is disposed in the central portion of the treatment tank 2 in the axial direction so that the ejection direction is upward, and the treated water supplied through the supply pipe 11 is directed toward the top plate 7. It is configured to be ejected.

  In the treatment tank 2, a space above the nozzle 3 outlet is set in a deaeration unit 12 for water to be treated. The height of the deaeration unit 12 is secured such that when the water to be treated is ejected from the nozzle 3 at a predetermined angle, water droplets at the bottom of the ejection cone can reach the side wall of the body unit 5. . On the other hand, the space below the nozzle 3 outlet is set in the treated water reservoir 13. Here, in order to improve the deaeration efficiency, the upper part of the treatment tank 2 is collided with the water ejected from the nozzle 3 and the falling water from the deaeration unit 12 to supply the treated water to the storage unit 13. A deaeration promoting unit 14 that delays the fall may be provided. The specific configuration and action of the deaeration promoting unit 14 are described in Japanese Patent Application No. 2006-13552 by the applicants of the present application.

A water level detection cylinder 15 for detecting the water level of the treated water is provided on the side of the body 5, and an upper portion of the water level detection cylinder 15 is communicated with the deaeration unit 12, and the water level detection is performed. A lower portion of the cylinder 15 is in communication with the storage portion 13. A water level sensor 16A as a transmission output type water level detecting means for detecting the water level in the processing tank 2 is inserted into the water level detection cylinder 15, and the water level sensor 16A controls the operation of the deaeration device 1. Connected to the control unit 17.

  The water level sensor 16A is capable of continuously detecting the water level in the treatment tank 2 under a reduced pressure condition. In this embodiment 1, the water level sensor 16A is provided between the metal electrode with insulation coating and the metal barrel portion 5. The capacitance type sensor detects the water level based on the change in capacitance.

  The water level detection cylinder 15 includes a first electrode (hereinafter referred to as an L electrode) 16B and a second electrode (hereinafter referred to as an L electrode) as contact output type water level (water level) detection means for detecting the water level in the processing tank 2. 16C is inserted, and these electrodes 16B and 16C are also connected to the control unit 17. The L electrode 16B and the H electrode 16C can be referred to as an auxiliary electrode, an output correction electrode, or a backup control electrode.

  Here, an allowable water level control zone between a lower limit water level (position) LL (for example, 50 mm) and an upper limit water level (position) HH (for example, 250 mm) is set in the treatment tank 2. This permissible water level control zone is a control zone in which inconvenience occurs in the deaeration device of the first embodiment when the water level is controlled beyond this control zone. The lower limit position LL is a lower limit water level required in the treatment tank 2 to enable continuous supply of degassed water, and the upper limit position HH is such that the treatment tank 2 nozzle 3 is not submerged in water. It is the upper limit water level set as follows.

  The water level sensor 16A is configured to be able to detect continuously from a water level lower than the lower limit position LL of the allowable water level control zone to a water level higher than the upper limit position HH of the allowable water level control zone. Yes.

  The L electrode 16B and the H electrode 16C detect the L position and the H position, respectively, based on the change in the water level in the processing tank 2 inside the allowable water level control zone. As will be described later, the water level in the treatment tank 2 is controlled to a set water level (target water level), but the set water level is set to exactly the middle between the L position and the H position.

  The treated water supply line 18 is connected to the supply port 8, and the treated water supply line 18 is connected to the strainer 19, the first pump 20, the on-off valve 21, and the first flow rate in this order from the upstream side. A sensor 22 is provided. The first pump 20 is for supplying to the nozzle 3 the water to be treated in which suspended substances are filtered by the strainer 19, and is connected to a first inverter 23, and the rotational speed thereof is the first. It is configured to be variable according to the output frequency from the inverter 23. The first inverter 23 is connected to the control unit 17 and is configured to operate according to a command signal from the control unit 17.

  The on-off valve 21 is for shutting off the supply of water to be treated to the nozzle 3 when the deaeration operation is stopped, and is connected to the control unit 17 (not shown). It is comprised so that it may operate | move by the command signal of. Further, the first flow rate sensor 22 is for detecting the supply flow rate of the water to be treated to the nozzle 3, and is connected to the control unit 17. Here, the flow rate detection signal input from the first flow rate sensor 22 to the control unit 17 is used to generate a command signal to the first inverter 23.

A treated water discharge line 24 is connected to the discharge port 9, and the treated water discharge line 24 is provided with a first check valve 25 and a second pump 26 in order from the upstream side. The second pump 26 is for discharging treated water from the inside of the treatment tank 2, and is connected to a second inverter 27, and the rotational speed thereof is variable according to the output frequency from the second inverter 27. It is configured to be. The second inverter 27 is connected to the control unit 17 and is configured to operate in response to a command signal from the control unit 17. Here, the water level detection signal input from the water level sensor 16 </ b> A to the control unit 17 is used to generate a command signal to the second inverter 27.

  Next, the vacuum suction means 4 will be described in detail. The vacuum suction means 4 mainly includes a water seal vacuum pump 28, a seal water recovery tank 29, and a seal water recirculation pump 30. The vacuum pump 28 is connected to the exhaust port 10 through a vacuum suction line 31. The vacuum suction line 31 is provided with a second check valve 32 and a vacuum sensor 33 in order from the exhaust port 10 side.

  The vacuum pump 28 depressurizes the inside of the treatment tank 2 and exhausts the gas separated from the water to be treated. The vacuum pump 28 is connected to the control unit 17 (not shown) and receives commands from the control unit 17. It is configured to operate in response to a signal. The vacuum sensor 33 detects the degree of vacuum in the processing tank 2 and is connected to the control unit 17 (not shown). Here, the vacuum degree detection signal input from the vacuum sensor 33 to the control unit 17 is used to generate a command signal to the vacuum pump 28.

  The vacuum pump 28 is connected to the treated water supply line 18 and the sealed water supply line 34 on the downstream side of the on-off valve 21. The sealed water supply line 34 is for supplying a part of the water to be treated to the vacuum pump 28 as sealed water. The sealed water supply line 34 includes a third check valve in order from the upstream side. 35 and a constant flow valve 36 are provided. The constant flow valve 36 suppresses a rise in the temperature of the sealed water by supplying the sealed water to the vacuum pump 28 at a constant flow rate during the operation of the deaeration device 1, thereby causing the vacuum pump 28 to reach a predetermined level. It is for operating at a vacuum level.

  Further, the vacuum pump 28 is connected to the seal water recovery tank 29 by a seal water recovery line 37 so that used seal water from the vacuum pump 28 is recovered into the seal water recovery tank 29. It is configured. The sealed water recovery tank 29 is connected to the treated water supply line 18 on the upstream side of the strainer 19 by a sealed water return line 38, and the sealed water return line 38 is connected to the sealed water in order from the upstream side. A reflux pump 30 and a fourth check valve 39 are provided. The sealed water recirculation pump 30 is for returning the sealed water collected in the sealed water collection tank 29 as treated water, and is connected to the control unit 17 (not shown). It is configured to operate in response to a command signal from 17.

  As the control procedure, the control unit 17 executes a first control procedure for executing normal water level control, and detects an abnormality of the first flow rate sensor 22, and also performs a backup control of the first pump 20 when an abnormality is determined. The second control procedure to be stored is stored. The second control procedure includes a third control procedure (shown in FIG. 3) for obtaining an average value of operating frequencies used for backup control of the first pump.

The first control procedure outputs a command signal to the first inverter 23 based on a flow rate detection signal from the first flow rate sensor 22, and also performs the first control based on a water level detection signal from the water level sensor 16A. In this control, a command signal is output to the two inverters 27. More specifically, a flow rate detection signal from the first flow rate sensor 22 is fed back as a command signal to the first inverter 23 that operates the first pump 20 via the control unit 17. The first pump 20 is operated such that its rotation speed is controlled in accordance with the output frequency of the first inverter 23 and the supply flow rate of the water to be treated matches a preset reference treatment flow rate. On the other hand, a water level detection signal from the water level sensor 16 </ b> A is fed back as a command signal to the second inverter 27 that operates the second pump 26 via the control unit 17. The rotation speed of the second pump 26 is controlled in accordance with the output frequency of the second inverter 27, and the water level in the processing tank 2 is operated so as to coincide with a preset target water level. Is done.

  The second control procedure includes a first step for determining whether or not a flow rate detection signal of the first flow rate sensor 22 is a set value (for example, 10% of a flow rate that should flow originally) or less, and a set value or less in the first step. Is determined, the second pump 26 is operated at a high speed to lower the water level in the processing tank 2, and then the second step of stopping the operation of the second pump 26, The first flow rate sensor 22 determines that there is an abnormality when a predetermined increase is detected in the water level detection signal of the water level sensor 16A within a set time (for example, about 10 seconds), assuming that there is a predetermined increase. When the abnormality of the second flow sensor 22 is determined in the third step and the third step, a fourth step of controlling the first pump 20 by the average value is included.

  Then, the third control procedure for obtaining the average value of the operating frequencies includes a first condition that the flow rate detected by the first flow rate sensor 22 is within a set range, as shown in FIG. The second condition that the flow rate detection signal from the flow rate sensor 22 is used for controlling the first pump 20 and the third condition that the set time elapses from the start of operation of the first pump 20 until the operation becomes stable. When the conditions are satisfied at the same time, the operating frequency of the first pump 20 is sampled at regular time intervals (for example, every 3 minutes) and sequentially stored. The stored set number is averaged to obtain an average value of the operating frequency.

(Basic operation of the first embodiment)
Hereinafter, the basic operation of the deaeration operation of the deaeration device 1 according to the first embodiment will be described. This deaeration operation is started, for example, by the input of an operation start signal based on water level information of a treated water tank (not shown) installed on the downstream side of the deaeration device 1. Alternatively, the deaeration operation is started by inputting an operation start signal from a timer unit (not shown) in which an operation start time and an operation end time are set, for example. When an operation start signal is input, the controller 17 opens the on-off valve 21 and operates the first pump 20, the second pump 26, and the vacuum pump 28. In addition, the said treated water tank can be provided in the upstream of the said process tank 2, and a circulation circuit can be comprised between the said treated water tank and the said process tank 2. FIG.

  In the degassing operation, the water to be treated is filtered through the strainer 19 and then pressurized by the first pump 20 while being pressurized through the water to be treated supply line 18 and the supply pipe 11. Supplied to the nozzle 3. The water to be treated supplied to the nozzle 3 is ejected upward from the axial center of the treatment tank 2 toward the top plate 7. The inside of the processing tank 2 is maintained in a depressurized state with a predetermined vacuum degree by controlling the operation of the vacuum pump 28 based on a vacuum degree detection signal from the vacuum sensor 33, and from the nozzle 3. The water to be treated is deaerated while rising up the deaeration unit 12 as water droplets.

  Next, when the water droplets to be treated collide with the side wall of the trunk portion 5, the water droplets fall into the central portion of the treatment tank 2. The to-be-treated water that has fallen into the water is pushed up to the upper part of the treatment tank 2 by colliding with the following ejected water, and further deaerated while the deaeration promoting unit 14 holds a predetermined amount.

  A part of the falling water that cannot be pushed up by the squirting water is pushed out from the lower part of the deaeration promoting unit 14 because the amount of the falling water in the deaeration promoting unit 14 exceeds a predetermined amount. The extruded water to be treated is further deaerated while descending along the side wall of the trunk portion 5 as flowing water.

The falling water that descends along the side wall of the body 5 is sequentially stored in the lower part of the treatment tank 2.
The stored treated water is further deaerated when present in the vicinity of the water surface in the storage unit 13 and finally secured as treated water. The treated water is discharged from the treatment tank 2 by the second pump 26.

(Normal water level control)
Now, constant flow control of the first pump 20 is performed during the deaeration operation. This constant flow rate control uses the PID control function (P control: proportional control, I control: integral control, D control: differential control) of the first inverter 23, and the reference flow rate of the water to be treated is designed in advance. The output frequency of the first inverter 23 is controlled so as to coincide with the processing flow rate. The control unit 17 can have the PID control function of the first inverter 23.

  In the PID control of the first inverter 23, as shown in FIG. 2, first, the control unit 17 receives a flow rate detection signal from the first flow rate sensor 22 and receives a command signal (for example, a current value of 4 to 20 mA, or 1-5V voltage value) is generated, and this command signal is output to the first inverter 23. Next, the first inverter 23 compares the command signal from the control unit 17 with a target value (that is, a current value or a voltage value corresponding to the reference processing flow rate) as a feedback value, and between these values. If there is a deviation, the output frequency is controlled so that this deviation becomes zero. The rotation speed of the first pump 20 is changed according to the output frequency of the first inverter 23.

  According to the constant flow rate control of the first pump 20, the operation is performed so that the supply flow rate of the water to be treated matches the reference treatment flow rate. Accordingly, the operating pressure of the first pump 20 is automatically adjusted so that the size of water droplets from the nozzle 3 is constant, and the first degassing efficiency is maintained while maintaining the predetermined degassing efficiency. The power consumption of the pump 20 is reduced.

  During the deaeration operation, the constant flow control of the second pump 26 is performed together with the constant flow control of the first pump 20. In this constant flow rate control, the water level control program uses the PID control function of the second inverter 27 in the same manner as the first inverter 23, and the water level in the treatment tank 2 is set in advance. The output frequency of the second inverter 27 is controlled so as to coincide with the water level. The control unit 17 can also have a PID control function of the second inverter 27.

  In the PID control of the second inverter 27, first, the control unit 17 receives a flow rate detection signal from the water level sensor 16A and generates a command signal (for example, a current value of 4 to 20 mA or a voltage value of 1 to 5 V). The command signal is output to the second inverter 27. Next, the second inverter 27 compares the command signal from the control unit 17 with a target value (that is, a current value or a voltage value corresponding to the set water level) as a feedback value, and between these values. If there is a deviation, the output frequency is controlled so that this deviation becomes zero. The rotation speed of the second pump 26 is changed according to the output frequency of the second inverter 27.

  According to the constant flow rate control of the second pump 26 performed together with the constant flow rate control of the first pump 20, the water level of the treated water in the treatment tank 2 is made constant, that is, the amount covered by the first pump 20. It operates so that the supply flow rate of treated water and the discharge flow rate of treated water by the second pump 26 become equal. Therefore, the operating pressure of the first pump 20 is automatically adjusted so that the size of water droplets from the nozzle 3 is constant, and the deaeration time in the processing tank 2 is constant. In addition, the operating pressure of the second pump 26 is automatically adjusted, and the power consumption of both the pumps 20 and 26 is simultaneously reduced while maintaining a predetermined deaeration efficiency.

  Further, during the deaeration operation, a part of the water to be treated flowing through the water to be treated supply line 18 is supplied to the vacuum pump 28 via the sealed water supply line 34. The treated water is used as sealed water by the vacuum pump 28 and then collected together with the gas sucked from the processing tank 2 into the sealed water recovery tank 29 through the sealed water recovery line 37. . In the sealed water recovery tank 29, the sealed water and the gas are separated, and the separated gas is released into the atmosphere. When the sealed water in the sealed water recovery tank 29 exceeds a predetermined water level, the sealed water recirculation pump 30 is driven, and the recovered sealed water is supplied to the treated water via the sealed water recirculation line 38. Returned to line 18.

  Here, in the said vacuum pump 28, since the sealing water is continuously replaced, the temperature rise of a sealing water does not arise. Therefore, the vacuum pump 28 can be stably operated at a predetermined ultimate vacuum. Moreover, in the said sealing water collection | recovery tank 29, since sealing water and gas are isolate | separated, sealing water is continuously replaced, concentration of the attracted gas does not arise. Therefore, corrosion of the sealed water recovery tank 29 can be effectively suppressed. Furthermore, since the recovered sealed water is reused as water to be treated, no waste water is generated.

(Abnormality detection of the first flow sensor 22)
Here, the abnormality detection operation of the first flow sensor 22 will be described. With reference to FIG. 2, in the processing step S <b> 1 (hereinafter, processing step SN is simply referred to as SN), the above-described normal water level control is performed. In S2, it is determined whether or not the flow rate detection signal of the first flow rate sensor 22 is equal to or less than a set value. If it is not determined in S2 that the flow rate has decreased, the process returns from S2 to S1.

  If YES is determined in S <b> 2, the process proceeds to S <b> 3 and water level lowering control is performed to lower the water level in the treatment tank 2. In this water level lowering control, while the control of the first pump 20 is continued, the second pump 26 is rotated at the highest speed (preferably the highest speed rotation, but the rotation that causes the water level to decrease even if it is not the highest speed rotation). It can be a speed). And if a water level falls to a setting value, water level fall control will be stopped and it will transfer to S4. In S4, after the water level lowering control is finished, it is determined whether or not the predetermined water level has risen within the set time, that is, in this embodiment 1, it is determined whether or not the water level rise speed is not less than the set value within the set time.

(Control when the flow sensor is abnormal)
If YES is determined in S4, the process proceeds to S5 to notify that the first flow sensor 22 is abnormal and notify the abnormality by a not-illustrated alarm device, and when the flow sensor abnormality of FIG. Perform the process. This abnormal process is backup control by rotating the first pump 20 at a constant speed with the average value of the operating frequencies of the first inverter 23 obtained in FIG. Thereby, the deaeration operation is continued despite the abnormality of the first flow rate sensor 22.

  If NO is determined in S4, it is determined that the first pump 20 or the on-off valve 21 is abnormal (water supply system abnormality), and the operation of the deaerator 1 is stopped.

(Control to obtain the average value of operating frequency)
Here, the control for obtaining the average value of the operation frequencies will be described with reference to FIG. In S <b> 10, it is determined whether or not the detected flow rate by the first flow rate sensor 22 is within a certain range with respect to the reference processing flow rate by the first pump 20. If YES is determined here, the process proceeds to S11 to determine whether or not the current control of the first pump 20 is control by the first flow rate sensor 22. If YES is determined, the process proceeds to S12 to determine whether or not a set time has elapsed from the start of operation of the first pump 20. If YES is determined here, the process proceeds to S13, and the operating frequency is sampled to be averaged and stored in a memory (not shown). When the abnormality of the first flow rate sensor 22 is determined in S5 of FIG. 2, the average value of the operation frequencies is obtained by averaging the stored operation frequencies for a predetermined number (predetermined time) from the abnormality determination time point. Ask for. It should be noted that, instead of averaging at the time of abnormality determination, it can be configured to average when the stored number reaches the set number.

  According to the first embodiment described above, an abnormality of the first flow rate sensor 22 can be detected using components necessary for the deaeration device such as the water level sensor 16A, and a device for detecting an abnormality of the flow rate sensor is provided. Simple and inexpensive. Further, since the abnormality determination is made based on the water level rising speed, it is possible to distinguish and determine the water supply system abnormality.

  Further, when the first flow rate sensor 22 is abnormal, the rotation speed of the first pump 20 is controlled at the average operating frequency to perform the backup operation, and the deaeration operation is continued without stopping. Can prevent economic damage. Moreover, when calculating | requiring the average value of the said operating frequency, by performing the process of S10-S11, the said 1st pump 20 can be drive | operated by the near frequency before a failure at the time of failure of a flow sensor.

  Further, according to the first embodiment, the adjustment work of the supply flow rate of the water to be treated can be facilitated, and the power consumption of the supply-side pump can be reduced. Further, according to the first embodiment, the adjustment work of the supply flow rate of the treated water and the discharge flow rate of the treated water can be facilitated, and the power consumption of both the supply side and the discharge side pumps can be simultaneously reduced. As a result, the maintenance of the deaeration performance and the reduction of the running cost can be realized at the same time, and in particular, the anticorrosion of the heat transfer pipe and the water supply pipe can be surely performed at a low cost.

1 is a schematic configuration diagram of a deaeration device according to Embodiment 1 of the present invention. FIG. 3 is a flowchart illustrating a control procedure according to the first embodiment. The flowchart figure explaining the other control procedure of the present Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Deaeration apparatus 2 Processing tank 16A Water level sensor 17 Control part (control means)
20 First pump 22 Flow rate sensor

Claims (3)

A treatment tank for storing the treatment liquid, a pump for supplying the treatment liquid to the treatment tank, a drain means for discharging the treatment liquid from the treatment tank, a flow rate sensor for detecting a supply flow rate of the treatment liquid, A liquid level sensor that detects a liquid level in the treatment tank, and a flow rate sensor in a water treatment device that controls the liquid level in the treatment tank to a set liquid level based on a liquid level detection signal of the liquid level sensor. An anomaly detection method,
A first step for determining whether the flow rate detection signal of the flow rate sensor is equal to or lower than a set value; a second step for stopping the operation of the drainage means when it is determined that the flow rate detection signal is equal to or lower than the set value in the first step; And a third step of determining that the flow sensor is abnormal when the liquid level detection signal of the liquid level sensor has a predetermined increase within a set time after two steps. . A deaeration device comprising a nozzle for ejecting a liquid to be treated into a treatment tank and a vacuum suction means in the treatment tank,
A first pump for supplying a liquid to be processed to the nozzle;
A flow sensor for detecting the supply flow rate of the liquid to be treated;
A first inverter for controlling the rotation speed of the first pump according to an output frequency;
A second pump for discharging the processing liquid from the processing tank;
A liquid level sensor for detecting the liquid level in the treatment tank;
A second inverter for controlling the rotation speed of the second pump according to an output frequency;
A control unit that outputs a command signal to the first inverter based on a flow rate detection signal from the flow sensor and outputs a command signal to the second inverter based on a liquid level detection signal from the liquid level sensor And
The control unit determines whether the flow rate detection signal of the flow rate sensor is equal to or lower than a set value, and stops the operation of the second pump when the first step determines that the flow rate detection signal is equal to or lower than the set value. And a third step of determining that the flow sensor is abnormal when the liquid level detection signal of the liquid level sensor has a predetermined increase within a set time after the second step. Qi device.   When the abnormality is determined in the third step, the control unit controls the first pump with an average operating frequency in a predetermined time immediately before the flow sensor is determined to be abnormal. Item 3. The deaeration device according to Item 2.

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