JP6924649B2 - Liquid transfer device, liquid transfer method, and drug addition device - Google Patents

Description

The present invention includes a liquid feeding device capable of suppressing the occurrence of gas lock when resuming liquid feeding after a liquid feeding stop period, a liquid feeding method using such a liquid feeding device, and such a liquid feeding device. Regarding the drug addition device.

If slime due to bacteria etc. is generated in the water used in the papermaking process, the quality of the product will deteriorate. In order to suppress such slime, an oxidizing slime control agent such as a bound chlorine compound is intermittently added several times a day.

Bound chlorine compounds such as monochloramine are unstable substances and decompose within a few hours after preparation. Therefore, a bound chlorine compound is generated in the paper mill and added to the water used in the paper manufacturing process.

The drug addition device used at this time usually includes a hypochlorite line equipped with a liquid feed pump for feeding a hypochlorite aqueous solution, and a hypochlorite line selected from ammonium salts, amines, amides, and imides. It has a nitrogen-containing compound line equipped with a liquid feed pump for supplying an aqueous solution of a nitrogen compound, and has a mixing chamber for injecting these chemicals into a line through which diluted water flows to generate a bound chlorine compound, and , It is equipped with a control mechanism for adjusting the discharge amount and discharge time of these pumps and the amount of diluted water, and a control mechanism for stopping the liquid feeding when an abnormality occurs.

The chemical solution tank of the hypochlorite aqueous solution or the nitrogen-containing compound aqueous solution is connected to the liquid feed pump in the chemical addition device by a hose, piping, etc. (hereinafter, these are collectively referred to as "pipe"). The addition device injects the drug into the pipe through which the diluted water flows at predetermined time intervals to generate a bound chlorine compound and supplies it to the water system to be added.

Bubbles are generated in the hypochlorite aqueous solution over time, and the bubbles generated in the piping from the chemical tank to the liquid feed pump often cause the gas lock of the liquid feed pump, that is, the inability to feed the liquid. ..

Therefore, a gas lock measure is taken in the chemical addition device to install a gas chamber open to the atmosphere to remove air bubbles generated on the upstream side in the liquid feeding direction of the liquid feeding pump.

However, air bubbles cannot be removed from the piping between the gas chamber and the suction port of the liquid feed pump, and air bubbles generated in this part of the piping (including so-called "gas" formed by combining multiple air bubbles, are included below. Similarly, when the liquid feed pump is gas-locked, the discharge amount is reduced and a predetermined amount of hypochlorite aqueous solution cannot be fed. Therefore, in order to remove air bubbles generated between the gas chamber and the suction port of the liquid feed pump, regular manual air bubble removal work is required, and improvement has been required.

In order to solve such a problem, Patent Document 1 proposes a technique of feeding a liquid in a larger amount than usual when the liquid feeding pump is started. However, such a method cannot be used for the delivery of an aqueous hypochlorite solution of a drug addition device that requires a fixed-quantity delivery.

Further, Patent Document 2 proposes a technique in which a flow detector and a bubble bleeding solenoid valve are provided in a liquid feeding pipe, a liquid flow stop is detected, the bubble bleeding solenoid valve is opened, and air is bleeded. ing. However, with this technique, not only air bubbles but also a small amount of chemical solution is lost.

Patent Document 3 describes a pump detecting means that detects the driving state of the pump body and the discharge state of the fluid and outputs a signal, and is installed in the piping system on the discharge port side of the pump head of the pump body and detects the flow of the fluid. A flow checker that outputs a signal and an air bleeding electromagnetic valve installed in the piping system between the upstream side of the flow checker and the downstream side of the discharge port of the pump head are provided, and the output signal by the pump detecting means is provided. A technique for automatically opening / closing and controlling an air bleeding electromagnetic valve by comparing it with an output signal from a flow checker is described.

Further, in Patent Document 4, an air detecting means for detecting air in a drug flowing through a drug supply line and a liquid feeding mode by the drug supply means when the air detecting means detects air in the drug are supplied. A technique is described in which a control means for operating a drug supply means by setting an air discharge operation mode for discharging air from a line is provided.

The techniques proposed in Patent Documents 3 and 4 require a flow checker, an air detection means, and a control device that controls an electromagnetic valve and a drug supply means based on their outputs, which increases the equipment cost. It gets higher.

Publication of Patent No. 2012-207571 Patent Publication 2001-207972 Patent Publication No. H05-60061 Publication of Patent No. 2011-173039

Therefore, the present invention is a liquid feeding device that retains a fixed amount of liquid feeding, does not waste the chemical liquid, is inexpensive, and can suppress the occurrence of gas lock when the liquid feeding is restarted after the liquid feeding stop period, such a liquid feeding device. It is an object of the present invention to provide a liquid feeding method using an apparatus and a drug addition apparatus provided with such a liquid feeding apparatus.

In order to solve the above problems, in the liquid feeding device of the present invention, a chemical liquid collecting unit and a liquid feeding pump are connected to a liquid feeding pipe in which one end is connected to a chemical liquid tank for accommodating the chemical liquid in the order of the flow direction of the chemical liquid. The branching portion and the first valve are connected, and the chemical liquid collecting portion is opened to the atmosphere by an opening provided at a position higher than the maximum height of the liquid level of the chemical liquid contained in the chemical liquid tank. are, in the branch portion, the chemical liquid to be supplied to the chemical recovery unit, and chemical recovery pipe having a second valve is connected and the chemical recovery unit, the chemicals collecting portion It is characterized in that it is connected to the chemical liquid tank via the liquid feeding pipe so that the liquid level height of the chemical liquid is equal to the liquid level height of the chemical liquid in the chemical liquid tank.

In addition to the above configuration, the liquid feeding device of the present invention has a first piping portion in which the connection between the liquid feeding pipe and the chemical liquid collecting unit is connected to both the chemical liquid tank and the chemical liquid collecting unit. , The second piping portion connected to both the chemical liquid recovery portion and the liquid feed pump is formed by connecting to two portions separated from each other at the bottom or near the bottom of the chemical liquid recovery portion. In addition, the connection portion of the first piping portion with the chemical liquid recovery portion may be provided at a position higher than the connection portion of the second piping portion with the chemical liquid recovery portion. can.

In the liquid feeding device of the present invention, in addition to the configuration directly above, the end opposite to the end connected to the branch portion of the chemical liquid recovery pipe is inserted into the chemical liquid recovery portion, and the tip thereof is the chemical liquid recovery portion. There is a gap between the chemical liquid recovery pipe, which is provided at a position higher than the connection point between the portion and the first piping portion and is inserted into the chemical liquid recovery portion, and the inner wall of the chemical liquid recovery portion. Can be formed.

In addition to the above configuration, the liquid feeding device of the present invention may have a configuration in which the other end of the liquid feeding pipe is connected to a pipe through which the liquid flows.

In addition to the configuration directly above, the liquid feeding device of the present invention may have a configuration in which the first valve is a check valve or a back pressure valve.

The liquid feeding method of the present invention is a liquid feeding method in which a chemical liquid is fed using any one of the above liquid feeding devices, and the first valve is kept in a closed state and the second valve is opened. Then, the liquid feed pump is operated so that the linear velocity of the chemical solution in the second piping portion is 20 mm / sec or more, and the chemical solution in the chemical solution recovery unit is transferred to the liquid feed pump and the branch. It is characterized by having a bubble removing step of circulating the pump, the second valve, and the chemical recovery pump in this order.

The drug addition device of the present invention accommodates a liquid feeding device connected to the above-mentioned liquid flowing pipe, the above-mentioned liquid flowing pipe to which a second liquid feeding pump is connected, and one end of the second chemical liquid. The second chemical tank is provided with a second liquid feeding pipe, the other end of which is connected to a pipe through which the liquid flows, and the second liquid feeding pipe is provided with the second liquid feeding pipe in the order of the flow direction of the second liquid. , A third liquid feed pump and a third valve are connected.

In the liquid feeding device of the present invention, a chemical liquid collecting unit, a liquid feeding pump, a branching portion, and a first one are connected to a liquid feeding pipe in which one end is connected to a chemical liquid tank for accommodating the chemical liquid, in order of the flow direction of the chemical liquid. a valve, are connected, chemicals collecting portion, the opening provided at a position higher than the maximum height of the liquid surface of the chemical contained in the chemical liquid tank is open to the atmosphere, the bifurcation, chemical chemicals collecting A chemical liquid recovery pipe provided with a second valve for supplying to the unit is connected , and the chemical liquid recovery unit is such that the liquid level height of the chemical solution in the chemical liquid recovery unit is the said in the chemical liquid tank. The configuration in which the chemical solution tank is connected to the chemical solution tank via the liquid transfer pipe so as to be equal to the liquid level height of the chemical solution suppresses an increase in the equipment cost, and bubbles are likely to be generated without wasting the chemical solution to be fed. It is possible to effectively prevent the generation of gas lock due to air bubbles generated in the piping of the chemical solution.

In addition to the above configuration, the liquid feeding device of the present invention has a first piping portion in which the connection between the liquid feeding pipe and the chemical liquid collecting unit is connected to both the chemical liquid tank and the chemical liquid collecting unit, and the chemical liquid collecting unit. The second piping portion connected to both the liquid feeding pump and the liquid feeding pump is formed by being connected to two places separated from each other at the bottom or near the bottom of the chemical liquid collecting portion, and is formed. Since the connection point of the piping part with the chemical solution recovery part is provided at a position higher than the connection point of the second piping part with the chemical solution recovery part, the chemical solution recovery part is supplied from the first piping part. Even if there are air bubbles in the first chemical solution, the air bubbles are prevented from being mixed into the chemical solution flowing from the chemical solution recovery part to the second piping part in advance, so that the occurrence of gas lock is prevented. NS.

In the liquid feeding device of the present invention, in addition to the configuration directly above, the end opposite to the end connected to the branch portion of the chemical liquid recovery pipe is inserted into the chemical liquid recovery unit, and the tip thereof is the chemical liquid recovery unit and the first A gap is formed between the chemical solution recovery pipe inserted into the chemical solution recovery section and the inner wall of the chemical solution recovery section, which is provided at a position higher than the connection point with the piping portion of the above. As a result, the structure becomes extremely simple, the equipment cost can be suppressed, and effective gas lock prevention becomes possible.

In addition to the above configuration, the liquid feeding device of the present invention has a configuration in which the other end of the liquid feeding pipe is connected to a pipe through which the liquid flows, so that, for example, the chemical liquid is fed to the pipe through which the diluted water flows. Therefore, it is possible to obtain an aqueous solution having a predetermined concentration, or to add a chemical solution to the liquid to be treated to perform chemical treatment.

In the liquid feeding device of the present invention, in addition to the configuration of the liquid feeding device connected to the above-mentioned piping through which the liquid flows, the first valve can be configured by a check valve or a back pressure valve. At this time, it is possible to prevent unexpected leakage of the chemical solution to the piping through which the liquid flows without using an expensive solenoid valve or electric valve that requires control, and the equipment cost is lower than when the solenoid valve or electric valve is used. It can be inexpensive.

The liquid feeding method of the present invention is a liquid feeding method in which a chemical liquid is fed by using any one of the above liquid feeding devices, and the first valve is kept in a closed state and the first valve is kept closed prior to the liquid feeding of the chemical liquid. After opening the second valve, the liquid feed pump is operated so that the linear velocity of the chemical liquid in the second piping portion is 20 mm / sec or more, and the chemical liquid in the chemical liquid recovery section is supplied to the liquid feed pump and the branch portion. , The second valve, and the bubble removing step that circulates in the order of the chemical liquid recovery unit again, so that the chemical liquid to be pumped is not wasted and gas lock occurs when the liquid feeding is restarted after the stop period. It becomes possible to prevent it effectively.

The drug addition device of the present invention has a liquid feeding device connected to a pipe through which any one of the above liquids flows, a liquid flowing pipe to which a second liquid feeding pump is connected, and a second chemical solution at one end. The second chemical tank for accommodating the liquid tank is provided with a second liquid feed pipe connected to a pipe at the other end through which the liquid flows, and the second liquid feed pipe is provided with the second liquid feed pipe in the order of the flow direction of the second liquid liquid. The configuration in which the third liquid feeding pump and the third valve are connected suppresses an increase in equipment cost, and restarts liquid feeding after a stop period without wasting the chemical liquid to be fed. It is possible to effectively prevent the occurrence of gas lock and stably supply the drug.

It is a model figure which shows the drug addition apparatus provided with an example of the liquid feeding apparatus of this invention. FIG. 2A is an enlarged model diagram of the vicinity of the liquid level gauge of the drug addition device of FIG. FIG. 2B is a model diagram showing another example near the liquid level gauge. It is a time chart which shows an example of the operation of the drug addition apparatus of FIG.

Hereinafter, the present invention will be described with reference to FIGS. 1 to 3.
<Drug addition device>
FIG. 1 is a model diagram showing a drug adding device including an example A of the liquid feeding device of the present invention, and FIG. 2 (a) is an enlarged model diagram of the vicinity of the liquid level gauge of the drug adding device of FIG. 2 (b) is a model diagram showing another example near the liquid level gauge, and FIG. 3 is a time chart showing an example of the operation of the drug addition device of FIG.

In FIG. 1, the portion surrounded by the broken line with the reference numeral A is an example A of the liquid feeding device of the present invention, and the first chemical solution M1 contained in the first chemical solution tank 1 is a liquid (in this example). It is a liquid feeding device that feeds liquid to the preparation pipe 11 in which (diluted water) is flowing.

The first chemical solution M1 is an aqueous solution of sodium hypochlorite in this example, but it may be an aqueous solution of a metal salt other than sodium. Alternatively, it can also be applied to other chemicals such as hydrogen peroxide solution and carbonated water in which bubbles are likely to be generated during the suspension period of the solution. Further, the liquid feeding device of the present invention can feed not only a chemical solution in which air bubbles are easily generated but also other chemical solutions, water and the like, and this case is also included in the present invention.

The flow direction of the first chemical solution M1 (the arrows in FIG. 1 indicate the flow directions of each chemical solution and the diluted water, respectively) in the first liquid feed pipe 2 to which one end is connected to the first chemical solution tank 1. ) In order, the liquid level gauge 3, the first liquid feed pump 4, the branch portion 2a, and the first valve 5 are connected, and the other end is the liquid feed destination of the first chemical solution M1. It is connected to a certain preparation pipe 11 through which diluted water flows via a first confluence portion 14.

Then, the chemical liquid recovery pipe 2b, which is provided with the second valve 7 and supplies the first chemical liquid M1 to the liquid level gauge 3 in the bubble removing step described later, is the first liquid feeding pipe via the branch portion 2a. It is connected to 2.

As will be described later, the liquid level gauge 3 which also functions as a chemical liquid recovery unit is made of a transparent vinyl chloride resin in this example, but may be made of glass so that the liquid level position can be visually recognized. It may have a transparent window portion. An opening 3f is formed at the upper end 3a of the liquid level gauge 3, and the height of the opening 3f is higher than the maximum height of the liquid level of the first chemical solution M1 contained in the first chemical solution tank 1. Is also getting higher.

As shown in a model in FIG. 2A, the first liquid feeding pipe 2 is connected to the bottom of the liquid level gauge 3 or two sides near the bottom of the liquid level gauge 3 so as to be separated from each other. Then, the connection portion 3d of the first piping portion 2c connected to both the first chemical liquid tank 1 and the liquid level gauge 3 with the liquid level gauge 3 is the liquid level gauge 3 and the first liquid feed pump. The second piping portion 2d connected to both of the 4 and the liquid level gauge 3 is provided at a position higher than the connection portion 3e.

The liquid level height of the first chemical solution M1 in the liquid level gauge 3 is equal to the liquid level height of the first chemical solution M1 in the first chemical liquid tank 1, and therefore, the liquid level gauge 3 should be observed. The remaining amount of the first chemical solution M1 in the first chemical solution tank 1 can be known.

Even if there are air bubbles in the first chemical solution M1 that has reached the liquid level gauge 3 from the first piping portion 2c due to the liquid feeding, the air bubbles will be generated in the connection portion 3e due to the above-mentioned height difference between the connection portion 3d and the connection portion 3e. Due to the gas chamber function due to the fact that the liquid level gauge 3 floats in the liquid level gauge 3 and is open to the atmosphere by the opening 3f of the upper end 3a of the liquid level gauge 3, the first chemical solution M1 in the liquid level gauge 3 It is released from the liquid surface into the atmosphere and removed. Therefore, it is prevented that the air bubbles in the first piping portion 2c generate a gas lock.

An existing liquid level gauge is already attached to the first chemical liquid tank 1, or a liquid level sensor is provided in the first chemical liquid tank 1, for example, so that the liquid level height of the first chemical liquid M1 is visually observed. If there is no need for confirmation, the first chemical solution M1 contained in the first chemical solution tank 1 is opened to the atmosphere by an opening provided at a position higher than the maximum liquid level. If there is, it can be used as a chemical liquid recovery unit instead of the liquid level gauge 3. Here, when the liquid level sensor is provided in the first chemical liquid tank 1, the device control means (not shown) of the liquid feeding device issues an alarm based on the liquid level position information detected by the liquid level sensor. Control may be performed such as emitting or switching the supply source of the first chemical solution M1 from the first chemical solution tank 1 to another chemical solution tank.

The first liquid feed pump 4 connected to the first liquid feed pipe 2 has chemical resistance to the first chemical solution M1, is excellent in quantification, and is provided by a device control means (not shown). The pump needs to be able to control the start / stop of liquid feeding and the liquid feeding speed. Further, as a type of pump, for example, a diagram pump can be mentioned, but any pump may be used as long as it satisfies the above requirements. Here, it is preferable to use a pump having less pulsation during liquid feeding, for example, a pulsation-free pump because a more stable bound chlorine compound can be obtained. In this example, a diagram pump is used as the first liquid feeding pump 4 and the third liquid feeding pump 23, which will be described later.

In this example, the second valve 7 of the chemical liquid recovery pipe 2b is a solenoid valve whose opening and closing is controlled by a device control means (not shown), but is a valve other than the solenoid valve, such as an electric valve or an air-operated valve, which can be opened and closed. There may be.

In this example, as shown as a model in FIG. 2A, the end opposite to the end connected to the branch portion 2a of the chemical liquid recovery pipe 2b is the opening of the liquid level gauge 3 which is the chemical liquid recovery portion. Along with being inserted into 3f, the tip 2b1 is provided at a position higher than the connection portion 3d between the liquid level gauge 3 and the first piping portion 2c, and the chemical liquid recovery pipe 2b inserted into the liquid level gauge 3 Since the gap 3c is formed between the liquid level gauge 3 and the inner wall 3b, the chemical liquid recovery pipe 2b does not impair the gas chamber function of the liquid level gauge 3.

The first chemical solution M1 that may contain bubbles flows out from the tip 2b1 of the chemical solution recovery pipe 2b in the bubble removing step described later, but as long as the first chemical solution M1 is supplied into the liquid level gauge 3. The chemical liquid recovery pipe 2b does not necessarily have to be inserted into the opening 3f. For example, a hole is made on the side surface of the liquid level gauge 3 at a position higher than the maximum height of the liquid level of the first chemical solution M1 housed in the first chemical solution tank 1, and the chemical solution recovery pipe 2b is inserted into the hole. Alternatively, the tip 2b1 of the chemical liquid recovery pipe 2b may be connected to a position higher than the connection portion 3d on the side surface of the liquid level gauge 3.

Further, FIG. 2B shows a liquid level gauge 3', which is another example of the chemical liquid recovery unit. In this example, the opening 3f is provided on the side surface, not on the upper end. Then, the end opposite to the end connected to the branch portion 2a of the chemical liquid recovery pipe 2b is inserted into the opening 3f of the liquid level gauge 3'which is the chemical liquid recovery portion, and the tip 2b1 is the liquid level gauge 3 Between the chemical liquid recovery pipe 2b, which is provided at a position higher than the connection portion 3d between the'and the first pipe portion 2c'and the liquid level gauge 3'and is inserted into the liquid level gauge 3', and the inner wall 3b of the liquid level gauge 3'. A gap 3c is formed in the space.

In the example A of the liquid feeding device shown in FIG. 1, the flow meter 6 is connected to the fourth piping portion 2f connected to both the branch portion 2a of the first liquid feeding pipe 2 and the first valve 5. ing. If necessary, the flow rate of the first chemical solution M1 detected by the flow meter 6 per unit time of the first chemical solution M1 is used to feed the first chemical solution M1 to the preparation pipe 11. Liquid feeding conditions such as liquid time may be controlled by a device control means (not shown).

A solenoid valve or an electric valve is used as the first valve 5 installed between the branch portion 2a and the first merging portion 14, and the opening / closing control is performed so as to have the same movement as the check valve described later. However, in Example A of this liquid feeding device, a check valve is used. When a check valve is used as the first valve 5, the check valve is automatically opened by the liquid feeding by the first liquid feeding pump 4 in the chemical injection process, and the pre-watering process other than the chemical injection process, the bubble removing process, and the bubble removing process, and In the after-water process, the back pressure of the diluted water flowing through the preparation pipe 11 automatically closes the water. Therefore, it is not necessary to control the opening and closing of the valve by the device control means, and at the same time, the device cost can be suppressed. A back pressure valve can be used as the first valve 5 instead of the check valve, and the back pressure valve operates automatically like the check valve and has the same effect as the check valve.

In the preparation pipe 11, in addition to the example A of the liquid feeding device, the second liquid feeding pipe 22 connected to the second chemical liquid tank 21 in which the second chemical liquid M2 is housed is provided with the second merging portion 16. It is connected via. In the second liquid feeding pipe 22, a third liquid feeding pump 23, a flow meter 24, and a third valve 25 (check valve in this example) are respectively provided in the order of the liquid feeding direction of the second chemical liquid M2. It is connected. In this example, the second merging portion 16 is provided on the downstream side in the diluted water flow direction of the first merging portion 14, but even if it is provided on the upstream side in the same direction of the first merging portion 14. good.

In this example, the second chemical solution M2 is a nitrogen-containing compound that produces a bound chlorine compound together with hypochlorite, that is, an aqueous ammonium salt solution such as ammonium chloride, ammonium sulfate, or ammonium bromide, or an amine such as sulfamic acid or urea. Classes, various amides, and aqueous solutions of imides can be mentioned, but this is not the case if the application is other than the production of a bonded chlorine compound. Hereinafter, an example in which an aqueous ammonium chloride solution is used as the second chemical solution M2 will be described.

In the preparation pipe 11, in this example, the diluted water feed pump 12, the flow meter 13, the first merging portion 14, the mixing chamber 15, and the second merging are arranged in the order of the flow direction of the diluted water. The part 16, the mixing chamber 17, and the pH meter 18 are connected, and the chemical addition device is used to connect the water system to which the bound chlorine compound is added from the tip of the pH meter 18 of the preparation pipe 11 downstream in the flow direction of the diluted water. Water containing the bound chlorine compound produced is added.

As the mixing chamber 15 and the mixing chamber 17, the mixing of the diluted water and the chemical solution sent to the diluted water is promoted (both the mixing chamber 15 and the mixing chamber 17), and the components of the first chemical solution M1 and the second chemical solution are used. A device for accelerating the reaction with the components of M2 to efficiently generate a bound chlorine compound (mixing chamber 17), in this example, a static mixer is installed, and stable bound chlorine is installed even though it is non-powered. The compound is produced.

Further, the pH meter 18 is for checking the operating status of the drug addition device, and when the pH detected by the pH meter 18 becomes an abnormal value, for example, the device control means (not shown) may be the first. Stop the first liquid feed pump 4, the third liquid feed pump 23, and the diluted water feed pump 12, for example, lighting or blinking of the red lamp, buzzer sound, display on the LED screen of the operation panel of the liquid feed device, Issue an alarm by communication or the like.

As described above, this drug addition device includes a device control device (not shown) provided with device control means for controlling the drug addition device of FIG. 1. The device control means is composed of devices necessary for controlling the drug addition device, such as a CPU, a RAM and ROM for holding programs and various data (may be a storage device such as a rewritable flash memory), a timekeeping timer, and an interface. Has been done.

The device control means includes LEDs, buttons, keyboards, etc. necessary for inputting and rewriting data necessary for device control, and buzzers, lamps, communication means, etc. for issuing an alarm when an abnormality occurs in the pH meter 18. It has.

Next, an example of the operation of the drug addition device including the example A of the liquid feeding device will be described with reference to FIG. In this example, the chemical addition device intermittently generates a bound chlorine compound and adds it to the water system to be added, for example, water in the papermaking process of a paper mill. Prior to the chemical injection step of adding the chemical to the target water system, the pre-water step and the bubble removing step are performed in this order, and the post-water step is performed after the chemical injection step.

<Pre-water process>
When the value of the timing timer approaches the timing of adding the drug to the target water system, the device control means operates the diluted water feed pump 12 to supply the diluted water to the preparation pipe 11 to prepare for the chemical injection step described later. (Fig. 3: Dilution process). The pre-watering step is usually carried out for 2 to 15 minutes. In this pre-watering step, the first liquid feeding pump 4 and the third liquid feeding pump 23 are stopped, and the second valve 7 is closed. The diluted water feed pump 12 continues to feed the diluted water until the end of the post-watering step described later.

In this pre-water step and the bubble removing step and the post-water step described later, the first valve 5 and the third valve 25, which are check valves, are maintained in a closed state by the back pressure of the diluted water.

<Bubble removal process>
After the completion of the pre-watering step, the device control means starts the bubble removing step prior to the chemical injection step. First, the second valve 7 is opened, and then the linear velocity of the first chemical solution M1 in the second piping portion 2d connected to both the liquid level gauge 3 and the first liquid feed pump 4 is 20 mm / The first liquid feeding pump 4 is operated so as to take a second or more (FIG. 3: bubble removing step, bubble removing operation).

In this bubble removing step, the second valve 7 is in the open state as described above, and the closed state of the first valve 5, which is a check valve, is maintained by the flow of the diluted water. The first chemical solution M1 does not leak to the preparation pipe 11, but enters the first liquid feed pump 4, the first liquid feed pump 4, and the branch portion 2a from the inside of the liquid level gauge 3 via the second pipe portion 2d. It circulates from the branch portion 2a through the third pipe portion 2e connected to both of the above, the second valve 7 through the chemical liquid recovery pipe 2b, and again in the order of the liquid level gauge 3.

Due to the circulation of the first chemical solution M1, the first chemical solution M1 in the second piping portion 2d, which may contain air bubbles, is fed at the above linear velocity and reaches the first liquid feed pump 4. .. Then, the third piping portion 2e and the branch portion between the first liquid feed pump 4 and the branch portion 2a, downstream in the flow direction of the first chemical liquid M1 of the first liquid feed pump 4, without causing a gas lock. It is collected from the tip 2b1 of the chemical liquid recovery pipe 2b into the liquid level gauge 3 via 2a and the chemical liquid recovery pipe 2b. Then, the bubbles in the first chemical solution M1 are removed by the gas chamber function in the liquid level gauge 3.

In the bubble removing step, the first chemical solution M1 circulates in such a route, and the first chemical solution M1 in the first chemical solution tank 1 is not directly involved in this circulation, so that there is a concern of deterioration due to contact with the outside air or the like. There is no.

As described above, the apparatus control means is so that the linear velocity of the first chemical solution M1 in the second piping portion 2d of the first liquid feeding pipe 2 becomes 20 mm / sec or more in this bubble removing step. Operate one liquid feed pump 4. Here, if the linear velocity of the first chemical solution M1 of the second piping portion 2d is less than 20 mm / sec, the gas lock prevention effect may not be sufficiently obtained. The preferred linear velocity is 30 mm / sec or higher. Although there is no particular upper limit to the linear velocity, the gas lock prevention effect is hardly improved even if the linear velocity is faster than 100 mm / sec, and the first liquid feeding pump 4 becomes large, so that the liquid feeding device is used. Equipment costs will rise.

The time to carry out the bubble removal step varies depending on the internal volume of the liquid level gauge 3 and the second piping portion 2d and the chemical injection interval. Perform for about 300 seconds.

In this example, when the value of the timing timer reaches the timing of the end of the bubble removing process, the device control means stops the first liquid feeding pump 4 and then closes the second valve 7 to remove bubbles. End the process. Here, an example in which the first liquid feeding pump 4 is temporarily stopped at the end of the bubble removing step will be described, but the bubble removing step and the chemical injection step are continuously performed without stopping the first liquid feeding pump 4. You may go there.

<Pharmaceutical injection process>
After the bubble removing step, the chemical injection step is usually performed 0 to 5 minutes after the bubble removing step is completed, before the bubbles are accumulated again in the second piping portion 2d and the effect of the bubble removing step is lost. When the value of the timing timer reaches the timing of starting the chemical injection process, the device control means operates the first liquid feed pump 4 and the third liquid feed pump 23 (FIG. 3: chemical injection process, liquid feed). Operation) and start the drug injection process.

In the chemical injection process, the first liquid feed pump 4 is operated while keeping the second valve 7 in the closed state, so that the first valve 5, which is a check valve, is automatically opened due to the liquid feed pressure. Then, the first chemical solution M1 is sent to the preparation pipe 11. Similarly, by operating the third liquid feeding pump 23, the third valve 25, which is a check valve, is automatically opened, and the second chemical liquid M2 is fed to the preparation pipe 11. The liquid feeding speed of the first liquid feeding pump 4 and the third liquid feeding pump 23 in the chemical injection step is such that the product (monochromamine in this example) is formed at a predetermined concentration in the diluted water. Prepare to.

The diluted water in the preparation pipe 11 is mixed with the first chemical solution M1 supplied from the first confluence 14 in the mixing chamber 15, and further with the second chemical solution M2 supplied from the second confluence 16. It is mixed in the mixing chamber 17 and added to the water system to be supplied together with the bound chlorine compound (monochromeramine in this example) produced by the components of these chemicals.

<After-water process>
When the value of the timing timer reaches the timing of stopping the chemical injection process, the device control means stops the first liquid feeding pump 4 and the third liquid feeding pump 23, and starts the after-water process (FIG. 3: FIG. After-water process). When these pumps are stopped, the first valve 5 and the third valve 25 are closed. After this, the water step is usually performed for 2 to 15 minutes, and the chemical remaining in the preparation pipe 11 is removed with diluted water. The device control means performs the after-water step for a predetermined time, then stops the diluted water feed pump 12, and then waits until the next pre-water step.

As described above, the drug addition device shown in FIG. 1 does not require an expensive device such as a sensor for detecting air bubbles or a judgment process based on the detection result by these devices, and only relatively simple control over time. Therefore, it is possible to effectively prevent the generation of gas lock due to the bubbles of the liquid feed pump of the chemical solution, and therefore, the bound chlorine compound can be stably added to the water system to be added.

Although the present invention has been described above with reference to preferred embodiments, the liquid feeding device, the liquid feeding method, and the drug addition device of the present invention are not limited to the configuration of the above embodiment.

Those skilled in the art can appropriately modify the liquid feeding device, the liquid feeding method, and the drug adding device of the present invention according to conventionally known knowledge. Such modifications are, of course, included in the category of the present invention as long as they have the configuration of the liquid feeding device, the liquid feeding method, and the drug adding device of the present invention.

1 1st chemical liquid tank 2 1st liquid supply pipe 2a Branch part 2b Chemical liquid recovery pipe 2b1 Tip 2c 1st pipe part 2d 2nd pipe part 2e 3rd pipe part 2f 4th pipe part 3 Liquid level gauge 3a Upper end 3b Inner wall 3c Gap 3d Connection 3e Connection 3f Opening 3'Liquid level gauge 4 First liquid feed pump 5 First valve 6 Flow meter 7 Second valve 11 Preparation piping 12 Diluted water feed pump ( Second liquid feed pump)
13 Flowmeter 14 First confluence 15 Mixing chamber 16 Second confluence 17 Mixing chamber 18 pH meter 21 Second chemical tank 22 Second liquid feeding pipe 23 Third liquid pump 24 Flowmeter 25 Third Valve A Example of liquid feeder M1 First chemical M2 Second chemical

Claims (7)

A chemical recovery unit, a liquid feed pump, a branch portion, and a first valve are connected in the order of the flow direction of the chemical solution to a liquid transfer pipe to which one end is connected to a chemical solution tank for accommodating the chemical solution.
The chemical recovery unit is opened to the atmosphere by an opening provided at a position higher than the maximum height of the liquid level of the chemical solution contained in the chemical solution tank .
A chemical solution recovery pipe provided with a second valve for supplying the chemical solution to the chemical solution recovery section is connected to the branch portion, and the chemical solution recovery pipe is connected to the branch portion .
The chemical solution collecting unit is connected to the chemical solution tank via the liquid feeding pipe so that the liquid level height of the chemical solution in the chemical solution collecting unit becomes equal to the liquid level height of the chemical solution in the chemical solution tank . A liquid feeding device characterized in that. The connection between the liquid feeding pipe and the chemical liquid collecting unit is connected to both the chemical liquid tank and the chemical liquid collecting unit, and to both the chemical liquid collecting unit and the liquid feeding pump. It is formed by connecting the connected second piping portion to the bottom or the vicinity of the bottom of the chemical recovery portion, which are separated from each other.
And,
The first aspect of claim 1 is characterized in that the connection portion of the first piping portion with the chemical liquid recovery portion is provided at a position higher than the connection portion of the second piping portion with the chemical liquid recovery portion. The liquid delivery device described. The end opposite to the end connected to the branch portion of the chemical liquid recovery pipe is inserted into the chemical liquid recovery portion, and the tip thereof is closer to the connection portion between the chemical liquid recovery portion and the first piping portion. 1. The liquid feeding device according to claim 2. The liquid feeding device according to any one of claims 1 to 3, wherein the other end of the liquid feeding pipe is connected to a pipe through which a liquid flows. The liquid feeding device according to claim 4, wherein the first valve is a check valve or a back pressure valve. A liquid feeding method for feeding a drug solution using the liquid feeding device according to any one of claims 1 to 5.
Prior to the delivery of the drug solution,
After keeping the first valve closed and opening the second valve, the liquid feed pump is operated so that the linear velocity of the chemical solution in the second piping portion is 20 mm / sec or more. The liquid feeding unit is characterized by having a bubble removing step of circulating the chemical solution in the chemical solution collecting section in the order of the liquid feeding pump, the branching section, the second valve, and the chemical solution collecting section again. Method. The liquid feeding device according to claim 4 or 5.
The pipe through which the liquid flows, to which the second liquid feed pump is connected,
One end is provided with a second chemical liquid tank for accommodating the second chemical liquid, and the other end is provided with a second liquid feeding pipe connected to a pipe through which the liquid flows.
A chemical addition device characterized in that a third liquid feed pump and a third valve are connected to the second liquid feed pipe in the order of the flow direction of the second chemical liquid.

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