JP4006353B2 - Defoamer addition system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antifoaming agent addition system for measuring a gas content in a flowing liquid and adding an appropriate amount of the antifoaming agent to the liquid.
[0002]
[Prior art]
Conventionally, for example, Patent Document 1 discloses a paper-making defoaming method for suppressing the generation of bubbles in a liquid in a paper-making system by adding an anti-foaming agent to white water in a paper machine, for example. In addition, a predetermined amount of self-emulsification type antifoaming agent is added to the white water pit by a pump, and at the same time, the amount of bubbles in the papermaking system is measured with a bubble detection device, and the output of the pump is controlled by the control device. A method of adding a foaming agent in proportion to the amount of bubbles in a papermaking system is disclosed.
[0003]
On the other hand, as described in Patent Document 2, as a dynamic metering device for the bubble content in a flowing liquid, a capacity for determining the apparent density of the flowing liquid containing bubbles in a transport line for engine oil or the like It contains bubbles under high and low pressure conditions by installing a flow rate measuring device and mass flow rate measuring device, a pressure regulating valve that adjusts the pressure of this flowing liquid to high and low pressure conditions, and a bubble content calculation formula There is one that quantifies the bubble content in the flowing liquid and the amount of bubbles in the dissolved gas.
[0004]
Moreover, as described in Patent Document 3, there is a gas content measuring method and a gas content measuring device for measuring the gas content of fluids such as papermaking pulp and coating paste.
[0005]
This is caused by a pressure change in the fluid caused by a pump or the like, and the transmission time, phase, and attenuation of the microwave signal at this time are measured when the microwave signal passes through the fluid, and are caused by the fluid pressure change. The gas content is determined based on changes in the transmission time, phase, and attenuation of the microwave signal.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 8-113891 [Patent Document 2]
Japanese Patent No. 2643020 [Patent Document 3]
JP 2001-525934 A [0007]
[Problems to be solved by the invention]
However, the bubble detection device in Patent Document 1 is merely described as measuring the amount of bubbles in the liquid, and its specific configuration is not disclosed. Further, in the inventions disclosed in Patent Documents 2 and 3, there is a problem that it is necessary to generate a pressure change in the fluid, the structure is complicated, and a complicated calculation is required.
[0008]
The present invention has been made in view of the above-described conventional problems, and with a simple configuration, the gas content in the flowing liquid is always continuously accurately measured, and an accurate amount of antifoaming agent is added. It aims at providing the system which performs.
[0009]
[Means for Solving the Problems]
The present invention continuously removes the liquid from the main flow path of the liquid and returns the liquid to the main flow path. The bypass pipe is disposed in the middle of the bypass pipe, and the gas content of the liquid flowing through the bypass pipe is reduced. An antifoaming agent pump for adding an antifoaming agent to the downstream side of the outlet by the bypass pipe in the main flow path, including a gas content measuring apparatus to be measured, and a downstream side of the gas content measuring apparatus in the bypass pipe; A control device for controlling the amount of defoaming agent added by the antifoaming agent pump based on the measurement result by the gas content measuring device, the gas content measuring device from the bypass pipe A liquid container having a liquid inlet and an outlet provided at a level higher than the inlet; and a detection level higher than the inlet in the liquid container and lower than the outlet. A hydraulic pressure sensor for detecting the liquid pressure at the detection level, and a liquid level control means for controlling the liquid level of the liquid in the outflow opening neighborhood, the liquid container has an inclined bottom The inflow port is provided in the vicinity of the lowermost end of the inclined bottom surface, the uppermost end of the inclined bottom surface is set to a level lower than the detection level, and the control device includes the hydraulic pressure sensor. And an arithmetic unit for calculating the gas content of the liquid between the detection level of the liquid pressure sensor and the liquid level based on the sensor output of the liquid and the information on the liquid level of the liquid. The above object is achieved by the antifoaming agent addition system.
[0010]
Further, in the antifoaming agent addition system, the main flow path is a circulation path of papermaking raw material water in a paper machine, and at least one circulation pump is disposed in the circulation path, and the bypass pipe is You may make it connect close to the downstream of the said circulation pump in the said main flow path.
[0011]
Furthermore, in the antifoaming agent addition system, the outlet of the bypass pipe may be provided open to a drain pan in at least one of a wire part and a press part in the paper making process.
[0012]
In the antifoaming agent addition system, the liquid level control means may control the flow rate of the liquid flowing from the inlet into the liquid container so that the liquid level is constant.
[0013]
Furthermore, in the antifoaming agent addition system, the liquid level control means may include a flow control valve provided in a pipe that supplies liquid to the inflow port.
[0015]
In the antifoaming agent addition system, the liquid level control means may include a horizontal opening formed horizontally so that the liquid overflows at the upper end of the liquid container.
[0016]
Further, in the antifoaming agent addition system, a ring-shaped overflow collecting tray surrounding the horizontal opening and collecting the liquid overflowing from the horizontal opening may be provided in the liquid container. .
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings.
[0018]
As shown in FIG. 1, an antifoaming agent addition system 50 according to an embodiment of the present invention adds an antifoaming agent to a raw water circulation system in a paper machine 52, and circulates papermaking raw water. A bypass pipe 56 for continuously taking out a part of the papermaking raw material water from the main flow path 54, which is a pipe, and returning it to the main flow path 54, is disposed in the middle of the bypass pipe 56, and flows through the bypass pipe. Downstream of the outlet 56 </ b> A by the bypass pipe 56 in the main flow path 54, including the gas content measuring apparatus 10 for measuring the gas content of the papermaking raw water and the downstream side of the gas content measuring apparatus 10 in the bypass pipe 56. On the side, an antifoaming agent pump 60 for adding an antifoaming agent, and a control device 62 for controlling the amount of antifoaming agent added by the antifoaming agent pump based on the measurement result by the gas content measuring device 10. Preparation It is configured.
[0019]
The paper machine 52 supplies the paper raw material water mixed with the raw material and the dilution water from the main channel 54 to the wire part 64 for paper making using the wire, and receives the white water after the paper making by the drain pan 65, and the white water After being stored in the tank 66, it is sent to the main flow path 54 again by the circulation pump 68 and circulated as papermaking raw water to the wire part 64 together with the raw water supplied from the seed box 70. .
[0020]
The code | symbol 72 of a figure shows the press part for pressing the paper rolled with the wire part 64 with a roll, and squeezing out the water | moisture content contained in paper.
[0021]
Reference numeral 74 is provided in the middle of the main flow path 54 on the downstream side of the seed box 70, and is a decurator for vacuum degassing of the papermaking raw material water. The circulation pump 78 includes a screen 78 for filtering the papermaking raw water, and an inlet 80 for rectifying the papermaking raw water and supplying it to the wire part 64.
[0022]
Reference numeral 72A denotes a drain pan for collecting white water squeezed in the press part 72, and 72B denotes a couch pit for collecting white water from the drain pan 72A. The white water in the couch pit 72B is returned to the white water tank 66.
[0023]
The bypass pipe 56 has an outlet 56 </ b> A at a position close to the downstream side of the seed box 70 on the downstream side of the circulation pump 68 in the main flow path 54. The return port 56 </ b> B is opened to the drain pan 65 in the wire part 64.
[0024]
Next, the gas content measuring apparatus 10 will be described in detail with reference to FIGS.
[0025]
The gas content measuring device 10 of the flowing liquid includes a liquid container 16 having a liquid inlet 12 and an outlet 14 provided at a higher level than the inlet 12, and the inlet in the liquid container 16. The liquid level sensor 18 is provided at a detection level L higher than 12 and lower than the outlet 14, and detects the liquid pressure at the detection level L, and the liquid level in the vicinity of the outlet 14. Based on the liquid level control means 20 for controlling Lh, the sensor output of the liquid pressure sensor 18 and the information on the liquid level Lh of the liquid, from the detection level L of the liquid pressure sensor 18 to the liquid level Lh And an arithmetic unit 22 that calculates the gas content of the liquid between the two. The arithmetic device 22 constitutes the control device 62 together with a shift control device 24A described later.
[0026]
In the middle of the bypass pipe 56, a manual valve 32, a flow meter 34, and a control valve 36 are arranged in this order from the main flow path 54 side.
[0027]
The liquid container 16 is a vertically long cylindrical body having an inclined bottom surface 38, and the inlet 12 is provided in the vicinity of the lowermost end of the inclined bottom surface 38. The level is lower than the detection level L of the pressure sensor 18.
[0028]
Here, the inlet 12 and the bypass pipe 56 connected to the inlet 12 have a considerably small cross-sectional area (about 1/5 in diameter ratio) with respect to the cross-sectional area of the cylindrical liquid container 16, thereby The liquid in the liquid container 16 is prevented from being disturbed by new fluid from the inlet 12.
[0029]
The outlet 14 at the upper end of the liquid container 16 is a horizontal opening formed horizontally so that the liquid overflows, and the shape of the outlet 14 and the flow rate of the liquid flowing in from the inlet 12 are controlled. The liquid level control means 20 is constituted by the control valve 36.
[0030]
For example, if the amount of liquid flowing into the liquid container 16 is increased by increasing the opening degree of the control valve 36, the liquid level Lh of the liquid at the outlet 14 increases, and conversely, if the control valve 36 is throttled. The liquid level Lh is lowered. Moreover, if a notch etc. are provided in the outflow port 14, the liquid level Lh will become low.
[0031]
Around the horizontal opening (outlet) 14 in the liquid container 16, a ring-shaped overflow collecting tray 40 for collecting the liquid overflowing from the outlet 14 is provided.
[0032]
Further, as shown in FIG. 3, two overflow ports 42 are provided on the bottom surface of the overflow collecting tray 40, from which the liquid is recovered by the recovery pipe 30. ing.
[0033]
The arithmetic unit 22 constitutes a part of the control unit 62 and detects the hydraulic pressure detection value at the detection level L detected by the hydraulic pressure sensor 18 and the detection in a state where no gas is contained. The detection value based on the liquid head pressure between the level L and the liquid level Lh is compared, and the amount of gas contained in the liquid above the detection level L is calculated based on the ratio or difference between the two. Have been to.
[0034]
In this case, if the opening degree of the control valve 36 is set to be a predetermined liquid level Lh, the calculation is easy.
[0035]
When the amount of liquid inflow into the liquid container 16 is frequently changed, the opening signal of the control valve 36 or the flow rate signal from the flow meter 34 is input to the arithmetic unit 22 as one variable, and the inflow is performed. The liquid level Lh may be calculated from the relationship with the amount, and the gas content may be calculated based on this.
[0036]
In the gas content measuring apparatus 10, the gas content can be measured easily and reliably and continuously without changing the pressure of the liquid to high or low or performing complicated calculations.
[0037]
Therefore, foaming in the main flow path 54 is controlled based on the measured gas content by controlling the amount of antifoaming agent added by the antifoaming agent pump 60 via the speed change control device 24A constituting a part of the control device 62. Can be suppressed by an optimal amount of antifoaming agent.
[0038]
In the example of the above embodiment, the outlet 56A of the bypass pipe 56 is disposed on the discharge side of the circulation pump 68 on the downstream side of the white water tank 66, but the present invention is not limited to this. Any paper-making raw material water may be taken out from any position of the main flow path 54. However, when it is provided adjacent to the downstream side of the circulation pump, the papermaking raw material water can be easily taken out. Therefore, for example, as shown by a two-dot chain line in FIG. A bypass pipe 57 having an outlet 57A may be provided adjacent to the discharge side of 76.
[0039]
Further, the antifoaming agent addition system 50 in the example of the above embodiment relates to the paper machine 52, but the present invention is not limited to this, as long as it suppresses foaming in the flowing liquid. The type of the liquid is not limited. Therefore, for example, it is generally applied to the case where bubbles are likely to be mixed in the liquid when separated and sent, such as a lubricating oil, a polymer-containing liquid, and a surfactant-containing liquid.
[0040]
In addition, in the case of a papermaking type | system | group, the said antifoamer has four types, a water-soluble active agent type, a self-emulsification type, an emulsion type, or an oil type, and any may be sufficient as it. In the case of petroleum-based liquids, the self-emulsifying type antifoaming agent or the like is selected according to the properties of the liquid.
[0041]
Further, in the gas content measuring apparatus 10, the outlet 14 as a part of the liquid level control means 20 is a horizontal opening. However, the present invention is not limited to this, and the liquid level is controlled. What is necessary is just to overflow the fluid while maintaining it constant.
[0042]
For example, a number of outflow holes may be formed at the same horizontal level in the vicinity of the upper end of the cylindrical liquid container. However, as in the example of the present embodiment, the horizontal opening of the outlet 14 is simple and the manufacturing cost can be reduced.
[0044]
However, when the inclined bottom surface 38 is provided as in the example of this embodiment, there is an advantage that the required volume of the liquid container 16 can be reduced.
[0045]
【The invention's effect】
Since the present invention is configured as described above, the gas content in the flowing liquid can be measured easily and continuously accurately, and an optimum amount of antifoaming agent can be added to the flowing liquid. It has the effect.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a paper machine to which an antifoaming agent addition system according to an embodiment of the present invention is applied. FIG. 2 is a partial block diagram showing a gas content measuring device in the antifoaming agent addition system. [Figure 3] The top view [Figure 4] The side view [Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Gas content measuring device 12 ... Inlet 14 ... Outlet 16 ... Liquid container 18 ... Liquid pressure sensor 20 ... Liquid level control means 22 ... Arithmetic device 30 ... Recovery pipe 34 ... Flow meter 36 ... Control valve 38 ... Inclination Bottom 40 ... Overflow collecting tray 50 ... Defoamer addition system 52 ... Paper machine 54 ... Main flow paths 56 and 57 ... Bypass pipes 56A and 56B ... Outlet 56B ... Return port 60 ... Defoamer pump 62 ... Control device 64 ... Wire part 65 ... Drain pan 66 ... White water tank 68, 76 ... Circulating pump 70 ... Seed box L ... Detection level Lh ... Liquid level

Claims (7)

A bypass pipe for continuously taking out the liquid from the liquid main flow path and returning it to the main flow path;
A gas content measuring device that is arranged in the middle of the bypass pipe and measures the gas content of the liquid flowing through the bypass pipe;
An antifoaming agent pump for adding an antifoaming agent to the downstream side of the outlet by the bypass pipe in the main flow path, including the downstream side of the gas content measuring device in the bypass pipe;
A control device for controlling the amount of defoamer added by the antifoaming agent pump based on the measurement result by the gas content measuring device,
The gas content measuring device includes a liquid container including a liquid inlet from the bypass pipe and an outlet provided at a higher level than the inlet, and is higher than the inlet in the liquid container, and A liquid pressure sensor that is provided at a detection level lower than the outlet and detects the liquid pressure at the detection level; and a liquid level control means that controls the liquid level of the liquid in the vicinity of the outlet. And
The liquid container is a vertically long cylindrical body having an inclined bottom surface, the inflow port is provided in the vicinity of the lowermost end of the inclined bottom surface, and the uppermost end of the inclined bottom surface is set to a level lower than the detection level.
,
The control device calculates a gas content of a liquid between a detection level of the liquid pressure sensor and a liquid level based on a sensor output of the liquid pressure sensor and information on a liquid level of the liquid. A defoamer addition system comprising an apparatus.   In Claim 1, the said main flow path is a circulation pipe of the papermaking raw material water in a paper machine, Comprising: At least 1 circulation pump is arrange | positioned in this circulation pipe, The said bypass pipe is the said main flow path in the said main flow path. An antifoaming agent addition system characterized by being connected close to the downstream side of the circulation pump.   3. The defoamer addition system according to claim 2, wherein an outlet of the bypass pipe is provided open to a drain pan in at least one of a wire part and a press part in a paper making process.   4. The liquid level control means according to claim 1, wherein the liquid level control means controls the flow rate of the liquid flowing into the liquid container from the inlet so that the liquid level is constant. Defoamer addition system.   5. The defoamer addition system according to claim 4, wherein the liquid level control means includes a flow rate control valve provided in a pipe that supplies liquid to the inflow port. In any one of claims 1 to 5, wherein the liquid level control means, the upper end of the liquid container, defoamer liquid is characterized in that it comprises a horizontally formed horizontal opening to extravasation Additive system. The antifoam additive addition according to claim 6 , characterized in that the liquid container is provided with a ring-shaped overflow collecting tray that surrounds the periphery of the horizontal opening and collects the liquid overflowing from the horizontal opening. system.

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