Water flow electrostatic device

Abstract

To provide a water flow electrostatic device capable of appropriately reducing the amount of new water used.SOLUTION: A water flow electrostatic device 10 charges a non-conductive sheet 90 by supplying water to the sheet 90. The water flow charging device 10 includes: a supply part 20 for supplying water to the sheet 90; a circulating flow path 30 for circulating the water supplied to the sheet 90 back to the supply part 20; and a cooling device 60 for cooling the water, which is provided in a middle of the circulating flow path 30.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a water flow charging device. [Background technology]

[0002] Patent Document 1 describes a manufacturing apparatus for producing an electret product by converting a non-conductive sheet made of a fibrous material into an electret. The manufacturing apparatus described in Patent Document 1 includes a water application means for pouring water onto one side of a sheet, and a suction nozzle that is disposed on the opposite side of the sheet from the water application means and sucks up the water poured onto one side of the sheet. The water poured onto the sheet is sucked up by the suction nozzle, and as the water passes through the inside of the sheet and moves from one side of the sheet to the other side, the sheet is charged by the frictional force acting between the water and the sheet. The water sucked up by the suction nozzle is drained to the outside of the manufacturing apparatus. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 062237 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in conventional manufacturing apparatuses including that of Patent Document 1, new water such as tap water is discharged through the water providing means and the suction nozzle, which poses a problem of increased consumption of new water. [Means for solving the problem]

[0005] The water flow charging device for solving the above problem is a water flow charging device that charges a non-conductive object by supplying water to the object, and includes a supply unit that supplies water toward the object, a circulation flow path that circulates the water supplied to the object to the supply unit, and a cooling device that is provided midway through the circulation flow path and cools the water.

[0006] According to this configuration, the water supplied from the supply unit to the object is circulated back to the supply unit through the circulation flow path, so that the water can be reused, thereby reducing the amount of new water used.

[0007] When water flows through the circulation flow path, the temperature of the water rises due to heat received from the pipes that make up the circulation flow path and frictional heat acting between the water and the pipes. As the water temperature rises, the electrical conductivity of the water supplied from the supply unit increases. This makes it easier for the charge of an electrically charged object to move to the water, which may reduce the degree of charge on the object.

[0008] In this regard, according to the above configuration, the water can be cooled by a cooling device provided in the middle of the circulation flow path. Therefore, the temperature rise of the water flowing through the circulation flow path can be suppressed, and the electrical conductivity of the water can be suppressed from increasing. This makes it possible to suppress the transfer of the charge of the charged object to the water, and thus the decrease in the degree of charge of the object. Therefore, the amount of new water used can be appropriately reduced. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a schematic configuration of a water flow charging device according to one embodiment. [Diagram 2] FIG. 2 is a graph showing the relationship between water temperature and water electrical conductivity. [Diagram 3] FIG. 3 is a graph showing the relationship between the temperature of water supplied to the nonwoven fabric sheet and the dust collection efficiency of the nonwoven fabric sheet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, one embodiment of a water flow charging device will be described with reference to FIGS. As shown in FIG. 1, the water flow charging device 10 is a device for charging a non-conductive sheet 90 by supplying water to the sheet 90 .

[0011] The sheet 90 is a nonwoven sheet made of synthetic resin. The water flow charging device 10 includes a conveying device 11, a supply unit 20, a suction unit 31, and a circulation flow path 30.

[0012] <Transportation device 11> As shown in FIG. 1, the conveying device 11 conveys a sheet 90 and includes a mesh-like endless belt 12 having a conveying surface 12a for conveying the sheet 90, and a plurality of rollers 13 for supporting the endless belt 12 so as to be movable in the conveying direction.

[0013] <Supply section 20> As shown in FIG. 1, the supply unit 20 supplies water to the sheet 90, and is disposed above the conveying device 11.

[0014] The supply unit 20 has a flow path portion 21 and an ejection port 22 that is located at the lower end of the flow path portion 21 and ejects water toward the sheet 90. <Suction part 31> As shown in FIG. 1, the suction unit 31 has a suction port that sucks in water that passes through and falls down the endless belt 12, and is disposed below the endless belt 12.

[0015] <Circulation flow path 30> As shown in FIG. 1, the circulation flow path 30 circulates the water supplied to the sheet 90 to the supply unit 20, and connects the suction unit 31 and the supply unit 20 together.

[0016] In the following description, the upstream side and downstream side in the flow direction of water flowing through the circulation flow passage 30 will simply be referred to as the upstream side and downstream side, respectively. In the circulation flow path 30, a gas-liquid separator 40, a first filter device 50, an introduction section 55, a cooling device 60, an ion exchanger 70, and a second filter device 80 are provided in this order from the upstream side.

[0017] In the circulation flow passage 30, between the first filter device 50 and the cooling device 60, a first pump 32 is provided for pumping the cooling water downstream. Further, in the circulation flow passage 30, between the second filter device 80 and the supply unit 20, a second pump 33 is provided for pumping the cooling water downstream.

[0018] (Gas-liquid separation device 40) The gas-liquid separation device 40 includes a storage tank 41 for temporarily storing water sucked through the suction section 31, an exhaust flow path 42 for discharging air (hereinafter referred to as exhaust air) from the storage tank 41, and a blower 43 provided midway along the exhaust flow path 42.

[0019] A silencer 44 for silencing exhaust noise is provided in the exhaust flow passage 42 downstream of the blower 43 in the exhaust flow direction. The blower 43 sucks in the exhaust air inside the storage tank 41 to create a negative pressure inside the storage tank 41 , and uses the negative pressure to suck water toward the storage tank 41 through the suction unit 31 .

[0020] The water that flows into the muffler 44 together with the exhaust air is stored in the muffler 44 and is discharged to the outside through a drainage section (not shown) connected to the muffler 44. (First filter device 50) The first filter device 50 collects foreign matter such as lint contained in the water flowing through the circulation flow path 30, and includes a filter 51 and a switching valve 52 provided upstream of the filter 51.

[0021] In this embodiment, two systems of the first filter device 50 are arranged in parallel, and the first filter device 50 to be used can be switched by opening and closing the switching valve 52 during maintenance or the like.

[0022] (Introduction 55) The introduction section 55 introduces tap water into the circulation flow path 30, and is equipped with a pipe 56 connected to the portion of the circulation flow path 30 between the first filter device 50 and the first pump 32, and a valve 57 that switches between allowing and prohibiting the introduction of tap water through the pipe 56.

[0023] (Cooling device 60) The cooling device 60 cools the water in the circulation flow path 30. The cooling device 60 includes a tank 61 for temporarily storing the water flowing through the circulation flow path 30, a heat exchanger 62 for exchanging heat with the refrigerant piping through which the refrigerant circulates, and a cooling pump 63 for pumping a portion of the water in the tank 61 toward the heat exchanger 62. In the heat exchanger 62, the water is cooled by heat exchange between the water and the refrigerant circulating through the refrigerant piping. The water that has passed through the heat exchanger 62 is led to the circulation flow path 30.

[0024] The cooling device 60 includes a control unit 64 that controls the driving mode of the cooling pump 63 , and a temperature sensor 65 that detects the temperature of the water discharged from the heat exchanger 62 . The control unit 64 controls the driving mode of the cooling pump 63 so that the water temperature detected by the temperature sensor 65 becomes equal to or lower than a target temperature. In this embodiment, the target temperature is 15°C.

[0025] (Ion exchanger 70) The ion exchanger 70 removes ions contained in the water flowing through the circulation flow path 30 by ion exchange, and is provided with a well-known ion exchange resin.

[0026] (Second filter device 80) The second filter device 80 collects foreign matter contained in the water flowing through the circulation flow path 30, and includes a filter 81 and a switching valve 82 provided upstream of the filter 81.

[0027] In this embodiment, two systems of second filter devices 80 are arranged in parallel, and the second filter device 80 to be used can be switched by opening and closing the switching valve 82 during maintenance or the like.

[0028] In the water flow electrification device 10 of the present embodiment, although water circulates within the circulation flow path 30, a small amount of water is discharged from the silencer 44 of the gas-liquid separation device 40. Therefore, in the present embodiment, a water level sensor 66 is provided that detects the water level within the tank 61 of the cooling device 60, and the circulation flow path 30 is configured to be replenished with tap water through the introduction part 55 based on the water level detected by the water level sensor 66.

[0029] Next, the operation of this embodiment will be described. 1, the water can be reused by circulating the water supplied from the supply unit 20 to the sheet 90 through the circulation flow path 30 back to the supply unit 20. This can reduce the amount of new water used.

[0030] Incidentally, when the water flows through the circulation flow path 30, the temperature of the water increases due to heat received from the pipes that constitute the circulation flow path 30, frictional heat acting between the water and the pipes, and the like. FIG. 2 shows the relationship between water temperature and water electrical conductivity.

[0031] 2, as the temperature of the water increases, the electrical conductivity of the water supplied from the supply unit 20 increases. Therefore, the charge of the electrically charged sheet 90 is more likely to move to the water, which may reduce the degree of charge of the sheet 90.

[0032] FIG. 3 shows the relationship between the temperature of the water supplied from the supply unit 20 to the sheet 90 and the dust collection efficiency of the filter element formed by the sheet 90. As shown in FIG. 3, the higher the water temperature, the lower the dust collection efficiency, that is, the lower the degree of electrostatic charge on the sheet 90.

[0033] According to this embodiment, the water can be cooled by the cooling device 60 provided in the middle of the circulation flow path 30. Therefore, the increase in temperature of the water flowing through the circulation flow path 30 can be suppressed, and the increase in the electrical conductivity of the water can be suppressed. This makes it possible to suppress the charge of the charged sheet 90 from moving to the water, and thus to suppress a decrease in the degree of charge of the sheet 90.

[0034] Next, the effects of this embodiment will be described. (1) The water flow electrification device 10 is provided with a cooling device 60 that is provided midway through the circulation flow path 30 and cools the water.

[0035] According to this configuration, the above-mentioned effect is achieved, and the amount of new water used can be appropriately reduced. (2) The water flow electrification device 10 includes an inlet 55 that introduces tap water into the circulation flow path 30, and an ion exchanger 70 that is provided midway through the circulation flow path 30 and removes ions contained in the water by ion exchange.

[0036] The amount of water flowing through the circulation flow path 30 becomes insufficient due to water adhering to the sheet 90 or part of the water supplied from the supply unit 20 to the sheet 90 being discharged to the outside. In order to make up for the lack of water, new water, for example tap water, is introduced into the circulation flow path 30. However, tap water contains ions such as calcium ions and chloride ions. In addition, metal ions may dissolve into the water from the inner surface of the pipe that constitutes the circulation flow path 30. Therefore, the concentration of ions contained in the water supplied from the supply unit 20 to the sheet 90 increases, and the electrical conductivity of the water supplied from the supply unit 20 increases. As a result, the charge of the charged sheet 90 is more likely to move to the water, which may reduce the degree of charging of the sheet 90.

[0037] In this regard, according to the above configuration, by providing the ion exchanger 70 in the middle of the circulation flow path 30, the ions contained in the water flowing through the circulation flow path 30 can be removed by ion exchange. This makes it possible to suppress an increase in the electrical conductivity of the water caused by introducing tap water from the inlet 55 or by metal ions dissolving in the water from the piping that constitutes the circulation flow path 30. This makes it possible to stably suppress a decrease in the degree of electrostatic charge of the sheet 90 over a long period of time.

[0038] (3) The ion exchanger 70 is provided downstream of the cooling device 60 . According to this configuration, the ion exchanger 70 is provided downstream of the cooling device 60, so that the ion exchanger 70 is provided at a position in the circulation flow path 30 closer to the supply unit 20 than the cooling device 60. Therefore, ions contained in the water can be removed in the portion of the circulation flow path 30 between the cooling device 60 and the supply unit 20. As a result, compared to the case where the ion exchanger 70 is provided upstream of the cooling device 60, the concentration of ions contained in the water supplied from the supply unit 20 to the sheet 90 can be reduced, so that the electrical conductivity of the water can be prevented from increasing. Therefore, the decrease in the degree of electrostatic charge of the sheet 90 can be further prevented.

[0039] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0040] The object of the present invention is not limited to the nonwoven fabric sheet 90, but may be, for example, a woven or knitted sheet made of synthetic resin fibers. In this embodiment, the ion exchanger 70 is provided downstream of the cooling device 60 . However, the ion exchanger 70 may be provided between the first pump 32 and the cooling device 60 .

[0041] The ion exchanger 70 may be omitted. In this case, ion-exchanged water or pure water may be introduced instead of tap water. In the cooling device 60 of the present embodiment, the driving mode of the cooling pump 63 is controlled to cool the water to the target temperature, but the water may be cooled to the target temperature by other well-known methods. [Explanation of symbols]

[0042] 10...Water flow charging device 11...Transportation device 12...Endless belt 12a...Transport surface 13. Laura 20…Supply section 21...Flow passage section 22...Injection port 30...Circulation flow path 31...Suction part 32…First pump 33…Second pump 40…Gas-liquid separation device 41…Storage tank 42...Discharge flow path 43…Blower 44...Silencer 50...First filter device 51...Filter 52...Switch valve 55…Introduction 56…Plumbing 57…Valve 60…Cooling device 61…Tank 62...Heat exchanger 63…Cooling pump 64...Control unit 65...Temperature sensor 66...Water level sensor 70…Ion exchanger 80...Second filter device 81...Filter 82...Switch valve 90…sheets

Claims

1. 1. A water flow charging device for charging a non-conductive object by supplying water to the object, comprising: A supply unit that supplies water toward the object; A circulation flow path that circulates the water supplied to the object to the supply unit; A cooling device is provided in the circulation flow path to cool the water. Water flow charging device.

2. An introduction section that introduces tap water into the circulation flow path; An ion exchanger is provided in the circulation flow path and removes ions contained in the water by ion exchange.

2. The water jet charging device according to claim 1.

3. The ion exchanger is provided downstream of the cooling device in the flow direction of the water flowing through the circulation flow path.

3. The water jet charging device according to claim 2.

4. The object is a nonwoven fabric sheet. The water flow charging device according to any one of claims 1 to 3.

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