Liquid tank

Abstract

To provide a liquid tank that can be formed by resin material by applying appropriate anti-static measures.SOLUTION: Siphon tube 4 is equipped with a suction part 40 that sucks the liquid stored in the liquid tank body into the siphon tube 4. Liquid L suctioned into the siphon tube 4 is discharged from the top surface 4a of the siphon tube 4. Furthermore, the suction part 40 of the siphon tube 4 is provided with a first ground wire 6. And furthermore, a second ground wire 7 is provided between the top surface 4a of the siphon tube 4 and the second supply and discharge hose H2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a liquid tank. [Background technology]

[0002] Generally, liquids such as high-purity semiconductor chemicals are filled into liquid tanks at production plants and shipped with a lid attached to a filling / removal port formed on the liquid tank. A known method for removing liquid from such liquid tanks is the siphon method, in which a gas such as nitrogen is introduced into the container, and the gas pressure causes the liquid to be sent out of the container (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-59993 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because the liquid tanks described above are made of metal, there is a problem in that metal components may be eluted into the liquid filled in the liquid tank.

[0005] Therefore, in the field of semiconductor manufacturing, where even higher purity is required, it has been desired to use resin materials such as fluororesins, which have excellent chemical resistance, instead of metals.

[0006] However, since resin materials such as fluororesin are insulating materials and therefore have a tendency to be charged, when friction occurs between the insulating material and the liquid contained in the liquid tank, static electricity is generated, which can cause the liquid to ignite, which makes it very difficult to form the container using resin materials such as fluororesin.

[0007] In view of the above, an object of the present invention is to provide a liquid tank that can be formed from a resin material by taking appropriate measures against static electricity. [Means for solving the problem]

[0008] The above object of the present invention can be achieved by the following means: Note that the parentheses indicate reference symbols of embodiments to be described later, but the present invention is not limited to these.

[0009] According to the invention of claim 1, a liquid tank body (2) in which a liquid (L) is contained, a siphon pipe (4) provided in the liquid tank body (2) and extending vertically; a drain pipe (second supply / drain hose H2) for draining the liquid (L) discharged from the siphon pipe (4) to a predetermined location (for example, a clean booth CB), The siphon tube (4) a suction section (40) that sucks the liquid (L) contained in the liquid tank body (2) into the siphon tube (4); a discharge part (upper surface 4a of the siphon tube 4) that discharges the liquid (L) sucked into the siphon tube (4) to the outside of the siphon tube (4), The suction part (40) is provided with a first earth wire (6), A second earth wire (7) is provided between the discharge portion (upper surface 4a of the siphon pipe 4) and the drain pipe (second supply / drain hose H2). R, an iron core (12) lined with a fluororesin (F7) is provided on the upper side of the suction part (40) and on the outer circumferential surface of the siphon pipe (4); A third earth wire (10) is provided to connect the suction portion (40) and the iron core (12). It is characterized by becoming.

[0010] According to the invention of claim 2, in the liquid tank (1) of claim 1, the first ground wire (6) and the second ground wire (7) are provided in a continuous manner.

[0011] According to a third aspect of the present invention, in the liquid tank (1) of the first or second aspect, the suction portion (40) has a tip (tip surface 40b) formed in a bell-mouth shape.

[0013] Claim 4 According to the invention, a liquid tank body (2) for storing a liquid (L) is provided. a siphon pipe (4) provided in the liquid tank body (2) and extending vertically; a drain pipe (second supply / drain hose H2) for draining the liquid (L) discharged from the siphon pipe (4) to a predetermined location (for example, a clean booth CB), The siphon tube (4) a suction section (40) that sucks the liquid (L) contained in the liquid tank body (2) into the siphon tube (4); a discharge part (upper surface 4a of the siphon tube 4) that discharges the liquid (L) sucked into the siphon tube (4) to the outside of the siphon tube (4), an iron core (12) lined with a fluororesin (F7) is provided on the upper side of the suction part (40) and on the outer circumferential surface of the siphon pipe (4); The device is characterized by being provided with a ground wire (third ground wire 10) connecting the suction portion (40) and the iron core (12). [Effects of the Invention]

[0014] Next, the effects of the present invention will be described with reference to the drawings. Note that the reference symbols in parentheses are those of the embodiments described below, but the present invention is not limited to these.

[0015] According to the invention of claim 1, the suction part (40) is provided with a first earth wire (6), and a second earth wire (7) is provided between the discharge part (upper surface 4a of the siphon pipe 4) and the drain pipe (second supply / drain hose H2). This makes it possible to significantly reduce the value of static electricity generated by suctioning the liquid (L) contained in the liquid tank body (2). Furthermore, according to the first aspect of the invention, by providing a third earth wire (10) connecting the suction part (40) and the iron core (12), even if the charge rate of the liquid (L) on the suction part (40) side increases significantly, the charge rate of the liquid (L) on the suction part (40) side can be reliably reduced. This makes it possible to further significantly reduce the value of static electricity generated on the suction part (40) side. According to the invention of claim 5, a ground wire (third ground wire (10)) is provided that connects the suction part (40) and the iron core (12). This makes it possible to significantly reduce the value of static electricity generated by suctioning the liquid (L) contained in the liquid tank body (2).

[0016] Therefore, according to the invention of claim 1 or 5, by taking appropriate measures against static electricity, it is possible to form the device using a resin material.

[0017] According to the invention of claim 2, the first ground wire (6) and the second ground wire (7) can be easily arranged.

[0018] According to the invention of claim 3, the entrance is widened when the liquid (L) contained in the liquid tank body (2) is sucked into the siphon tube (4), thereby reducing turbulence caused by a mixture of gas and liquid, and thereby reducing the electrification rate of the liquid (L). [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 2 is an explanatory diagram illustrating an arrangement state of a liquid tank according to an embodiment of the present invention. [Figure 2] FIG. 10 is a vertical cross-sectional view showing a state in which the siphon pipe according to the embodiment is installed in the lid portion and a second supply / discharge hose is installed in the siphon pipe. [Figure 3] 3A and 3B show a ground wire attachment plate according to the embodiment, in which FIG. 3A is a plan view and FIG. 3B is a longitudinal cross-sectional view. [Figure 4] FIG. 3 is a longitudinal cross-sectional view of a suction unit according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of a liquid tank according to the present invention will be described in detail with reference to the drawings. In the following description, when directions such as up, down, left, and right are indicated, they refer to up, down, left, and right when viewed from the front of the illustration.

[0022] <Outline of the liquid tank> The liquid tank according to this embodiment can be formed from a resin material by taking measures against static electricity, and specifically, as shown in Fig. 1, the liquid tank 1 is mainly composed of a liquid tank body 2, a lid 3, and a siphon tube 4. Each component will be described in detail below.

[0023] <Explanation of the liquid tank body> The liquid tank body 2 is made of stainless steel such as SUS304, and is formed in the shape of a vertically elongated cylinder with an open top surface 2a and a closed bottom surface 2b, forming a hollow interior, as shown in Fig. 1. As shown in Fig. 1, a recess 20 is integrally formed in the center of the bottom surface 2b. Also, as shown in Fig. 1, a circular flange 21 is integrally formed on the top surface 2a so as to protrude in the circumferential direction.

[0024] The liquid tank body 2 configured as above is filled with and contains a liquid L such as a high-purity semiconductor chemical, as shown in Fig. 1. The inner peripheral wall surface of the liquid tank body 2 shown in Fig. 1 comes into contact with the liquid L, and therefore is provided with a lining F1 of about 2 to 3 mm in thickness, including the recessed portion 20, made of a thermoplastic fluororesin such as PTFE (polytetrafluoroethylene), to prevent metal components from eluting into the liquid L.

[0025] <Explanation of the lid> As shown in Fig. 1, the lid portion 3 is capable of closing the top surface 2a of the liquid tank body 2, and is formed of stainless steel such as SUS304 and has a circular shape. More specifically, as shown in Fig. 2, the lid portion 3 is composed of a first lid portion 30 and a second lid portion 31 that is integrally provided on the top surface 30a of the first lid portion 30. The first lid portion 30 is formed in a circular shape (a horizontally elongated rectangular shape in Fig. 2 cross section), and the second lid portion 31 is formed in a circular shape (a rectangular shape in Fig. 2 cross section) that is shorter in width than the first lid portion 30. Furthermore, a through-hole 32 that penetrates vertically is provided in the center of each of the first lid portion 30 and the second lid portion 31, as shown in Fig. 2.

[0026] Thus, the first lid portion 30 of the lid portion 3 configured in this manner can be placed on the upper surface of the flange portion 21, as shown in Fig. 1, and can be connected and fixed to the flange portion 21 with the bolt B1 shown in Fig. 1. This allows the lid portion 3 to close the upper surface 2a of the liquid tank body 2.

[0027] Meanwhile, as shown in FIG. 1, a first supply / exhaust hose H1 is connected to the left side surface 30b of the first lid portion 30 of the lid portion 3. This first supply / exhaust hose H1 is connected to either a supply valve V1 or an exhaust valve V2 located on the clean booth CB side of a semiconductor manufacturing facility, as shown in FIG. 1. When the first supply / exhaust hose H1 is connected to the supply valve V1, a gas such as nitrogen is supplied into the liquid tank body 2 via the supply valve V1 through the first supply / exhaust hose H1. This causes the inside of the liquid tank body 2 to be pressurized. When the first supply / exhaust hose H1 is connected to the exhaust valve V2, a gas such as nitrogen can be exhausted to the outside of the liquid tank body 2 via the first supply / exhaust hose H1 and the exhaust valve V2. In addition, the inner wall surfaces of the lid portion 3 that may come into contact with the liquid L, i.e., the inner wall surface 30c of the first lid portion 30 and the inner wall surface 31a of the second lid portion 31 as shown in Figure 2, are also provided with a lining F2 made of a thermoplastic fluororesin such as PTFE (polytetrafluoroethylene) and having a thickness of approximately 2 to 3 mm.

[0028] <Siphon tube explanation> As shown in Fig. 1, the siphon tube 4 extends vertically, i.e., in the vertical direction, from the upper surface 2a of the liquid tank body 2 to the inside of the recess 20 of the liquid tank body 2, and is disposed within the liquid tank body 2. More specifically, as shown in Fig. 2, the siphon tube 4 is formed in the shape of an elongated cylinder with an open upper surface 4a and lower surface 4b and an internal cavity. As shown in Fig. 2, the siphon tube 4 is made of a thermoplastic fluororesin such as PTFE (polytetrafluoroethylene) or PFA (perfluoroalkoxyalkane). The siphon tube 4 is made of a thermoplastic fluororesin because it comes into contact with the liquid L.

[0029] On the other hand, as shown in Fig. 2, a suction part 40 is attached and fixed to the lower surface 4b of the siphon tube 4. This suction part 40 is made of stainless steel such as SUS304, and as shown in Fig. 4, the base end surface 40a and the tip end surface 40b are open, and the suction part 40 is formed in a short cylindrical shape with an internal cavity. As shown in Fig. 4, the tip end surface 40b of this suction part 40 is machined into a bell-mouth shape.

[0030] Thus, when attaching and fixing such suction part 40 to the underside 4b of the siphon tube 4 as shown in Figure 2, the underside 4b of the siphon tube 4 is thermally processed and the suction part 40 is inserted into the underside 4b of the siphon tube 4. Then, the suction part 40 is attached and fixed to the underside 4b of the siphon tube 4 with the screws B4 shown in Figure 2. In this way, the suction part 40 can be attached and fixed to the underside 4b of the siphon tube 4.

[0031] 2, a flange portion 41 that is convex in cross section and protrudes in the circumferential direction is integrally provided on the upper surface 4a of the siphon tube 4. As shown in FIG. 2, a lining F4 made of a thermoplastic fluororesin such as PTFE (polytetrafluoroethylene) and having a thickness of about 2 to 3 mm is applied to the lower surface 41a of the flange portion 41.

[0032] Thus, when disposing the siphon tube 4 configured as described above in the liquid tank body 2 as shown in Fig. 1, it is inserted into the through-hole 32 shown in Fig. 2. Then, the flange portion 41 integrally provided on the upper surface 4a of the siphon tube 4 so as to protrude is placed on the upper surface 31b of the second lid portion 31 shown in Fig. 2. In this state, the flange portion 41 and the second lid portion 31 are connected and fixed together with the bolt B2 shown in Fig. 2, whereby the siphon tube 4 can be disposed in the liquid tank body 2 as shown in Fig. 1.

[0033] Meanwhile, as shown in Fig. 2, a pair of packings 5 ​​are placed on the upper surface 41b of the flange portion 41. Then, as shown in Fig. 2, a circular flange portion H2b, which is integrally provided to protrude in the circumferential direction from the lower surface H2a of the second supply / discharge hose H2, is placed on the upper surface 41b of the flange portion 41, sandwiching the pair of packings 5 ​​therebetween. In this state, the flange portion H2b and the flange portion 41 are connected and fixed together with bolts B3 shown in Fig. 2, so that the flange portion H2b and the flange portion 41 can be connected and fixed together as shown in Fig. 1.

[0034] In this state, if a gas such as nitrogen is supplied into the liquid tank body 2 through the first supply / drain hose H1 shown in Fig. 1, the liquid tank body 2 is pressurized, and due to the siphon principle, the liquid L contained in the liquid tank body 2 is sucked through the suction portion 40 of the siphon tube 4 shown in Fig. 2. The sucked liquid L then passes through the siphon tube 4 and is discharged from the top surface 4a shown in Fig. 2. The liquid L then passes through the through hole 5a of the packing 5 and flows into the second supply / drain hose H2. As shown in Fig. 1, the second supply / drain hose H2 is connected to either the drain valve V3 or the liquid supply valve V4 on the clean booth CB side. If the second supply / drain hose H2 is connected to the drain valve V3, the liquid L that has flowed into the second supply / drain hose H2 will be drained to the clean booth CB side via the drain valve V3. When the second supply / drain hose H2 is connected to the liquid supply valve V4, the liquid L can be supplied from the second supply / drain hose H2 into the siphon tube 4 via the liquid supply valve V4. This allows the liquid L to be supplied from the outside (in this embodiment, from the clean booth CB side) into the liquid tank body 2. When supplying the liquid L into the liquid tank body 2, the first supply / drain hose H1 is connected to the exhaust valve V2, and gas such as nitrogen is exhausted to the outside of the liquid tank body 2 via the first supply / drain hose H1 and the exhaust valve V2.

[0035] Incidentally, thermoplastic fluororesin such as PTFE (polytetrafluoroethylene) can prevent metal components from eluting into the liquid L, but because it is an insulating material, it has a tendency to be charged. Therefore, as explained above, when the liquid L in the liquid tank body 2 is discharged to the outside (in this embodiment, to the clean booth CB side), friction occurs between the thermoplastic fluororesin and the liquid L, which generates static electricity, which may cause pinholes (holes) on the lining surface due to sparks, or, if the liquid L is an organic solvent, may cause the liquid L to ignite.

[0036] Therefore, the inventors conducted the following preliminary test. That is, they applied a voltage inside the siphon tube 4 to check whether a spark occurred or whether a discharge occurred to the outside. As a result, a discharge to the outside was observed at approximately 24,000 V, and ultimately a pinhole occurred in the lining (a hole opened up). Based on these results, the inventors came to the conclusion that static electricity sparks could be prevented if the potential of static electricity generated inside the siphon tube 4 was kept below approximately 24,000 V.

[0037] Furthermore, as a result of further intensive research, the inventors have found that when the liquid L contained in the liquid tank body 2 has been sucked up and is replaced with gas supplied to the liquid tank body 2, the charge rate rises suddenly and the value of static electricity rises significantly. This is thought to be because, when the liquid L contained in the liquid tank body 2 is sucked up by the suction part 40, a turbulent flow of mixed gas and liquid is generated between the tip surface 40b of the suction part 40 (see FIG. 2) and the recess 20 (see FIG. 1).

[0038] In consideration of the above, in this embodiment, a first earth wire 6 shown in Fig. 2 is provided on the suction portion 40 side of the siphon tube 4, and a second earth wire 7 is provided between the upper surface 4a of the siphon tube 4 and the second supply / discharge hose H2. This point will be explained in detail below.

[0039] <Explanation of the earth wire> 2, the first earth wire 6 passes through the inside of the siphon tube 4 and the suction part 40, exits from the tip surface 40b, and is positioned so as to be located on the outer peripheral surface side of the siphon tube 4. And, as shown in FIG. 2, a first terminal 8a is attached and fixed to the tip end 6a of this first earth wire 6.

[0040] Thus, the first terminal 8a is located on the side of a screw mounting hole 40c that penetrates the right side of the base end surface 40a of the suction part 40 shown in FIG. 4 and is attached and fixed to the suction part 40 using the screw B4 shown in FIG. 2. This fixes the position of the first ground wire 6 to the outer peripheral surface of the siphon tube 4. In this way, static electricity generated on the suction part 40 side by suction of the liquid L flows to the first terminal 8a via the first ground wire 6, and the static electricity that flows to the first terminal 8a then flows to the suction part 40 through the screw B4. This reduces the charge rate of the liquid L on the suction part 40 side, significantly reducing the amount of static electricity generated on the suction part 40 side. Furthermore, fixing the position of the first ground wire 6 to the outer peripheral surface of the siphon tube 4 reduces the resistance to the flow of static electricity caused by fixed parts.

[0041] On the other hand, as shown in FIG. 2, the first ground wire 6 extends to the upper surface 4a of the siphon tube 4, and the base end 6b of the first ground wire 6 is connected to the tip end 7a of the second ground wire 7. As shown in FIG. 2, a second terminal 8b is attached and fixed to the base end 7b of the second ground wire 7, and this second terminal 8b is attached and fixed to the ground wire mounting plate 9 using a screw B5. More specifically, the ground wire mounting plate 9 is made of stainless steel such as SUS304, and as shown in FIG. 3(a), it is composed of a main body 90 that is circular in plan view and a support portion 91 that is rectangular in plan view and is integral with the main body 90. As shown in FIG. 3(a), a circular through-hole 90a is provided in the center of the main body 90, penetrating it in the vertical direction as shown in FIG. 3(b). At the position where the through-hole 90a is formed, a magnifying glass-shaped mounting portion 90b is integrally provided on the main body 90 as shown in Fig. 3(a), and this mounting portion 90b is formed by being bent upward as shown in Fig. 3(b). Note that a circular mounting hole 90b1 is provided through the mounting portion 90b as shown in Fig. 3.

[0042] On the other hand, as shown in FIG. 3, a circular through-hole 91b is provided on the base end portion 91a side of the support portion 91 so as to penetrate in the up-down direction.

[0043] Thus, the second terminal 8b is positioned in the mounting hole 90b1 of the thus configured ground wire mounting plate 9, and is attached and fixed to the ground wire mounting plate 9 using a screw B5 shown in FIG. 2. Then, as shown in FIG. 2, the ground wire mounting plate 9 is sandwiched between a pair of gaskets 5, and the circular flange portion H2b, which protrudes circumferentially from the lower surface H2a of the second supply / drain hose H2, is placed on the upper surface 41b of the flange portion 41, sandwiching the pair of gaskets 5. In this state, the flange portion H2b is connected and fixed to the flange portion 41 using a bolt B3 shown in FIG. 2, thereby connecting and fixing the flange portion H2b to the flange portion 41, as shown in FIG. 1. As a result, the second ground wire 7 is fixed in position between the upper surface 4a of the siphon pipe 4 and the second supply / drain hose H2.

[0044] In this way, static electricity generated inside the siphon tube 4 flows to the second terminal 8b via the second earth wire 7, and the static electricity that flows to the second terminal 8b flows through the screw B5 to the earth wire mounting plate 9. As a result, the charge rate of the liquid L inside the siphon tube 4 decreases, and the value of the static electricity generated inside the siphon tube 4 can be significantly reduced.

[0045] 2 on the suction section 40 side of the siphon tube 4, and the second ground wire 7 between the upper surface 4a of the siphon tube 4 and the second supply / discharge hose H2, it is possible to significantly reduce the amount of static electricity generated on the suction section 40 side of the siphon tube 4 and inside the siphon tube 4. This makes it possible to sufficiently eliminate static electricity generated inside the siphon tube 4.

[0046] Therefore, according to the present embodiment described above, by taking appropriate measures against static electricity, it is possible to form the device using a resin material.

[0047] While the above-described static electricity countermeasures are sufficient, this embodiment takes additional measures against static electricity. Specifically, when the suction unit 40 sucks the liquid L contained in the liquid tank body 2, the charge rate of the liquid L may increase, particularly on the suction unit 40 side. Therefore, in this embodiment, in addition to the first ground wire 6, a third ground wire 10 is provided as shown in FIG. 2. As shown in FIG. 2, the third ground wire 10 has a tip end 10a attached and fixed to a third terminal 8c, which is attached and fixed to the suction unit 40 using a screw B4 shown in FIG. 2. Furthermore, as shown in FIG. 2, the third ground wire 10 extends upward, and its base end 10b is attached and fixed to a fixing portion 11, the outer periphery of which is covered with a lining F6 of approximately 2 to 3 mm made of a thermoplastic fluororesin such as PTFE (polytetrafluoroethylene).

[0048] The fixed portion 11 is attached and fixed to the iron core 12, as shown in FIG. 2. The iron core 12 is made of stainless steel such as SUS304, and as shown in FIG. 2, has an elongated rectangular cross section. It is provided with a lining F7 of approximately 2 to 3 mm thick made of a thermoplastic fluororesin such as PTFE (polytetrafluoroethylene). As shown in FIG. 2, the iron core 12 is located above the suction portion 40, extends to the underside 41a of the flange portion 41, and is fixedly disposed on the outer peripheral surface of the siphon tube 4. As a result, static electricity flowing to the first terminal 8a via the first ground wire 6 flows to the suction portion 40 through the screw B4, while flowing to the fixed portion 11 via the third ground wire 10. Furthermore, the static electricity flowing to the fixed portion 11 flows to the flange portion 41 through the iron core 12.

[0049] Thus, by doing this, even if the charge rate of the liquid L on the suction section 40 side increases significantly, the charge rate of the liquid L on the suction section 40 side can be reliably reduced, thereby further significantly reducing the value of the static electricity generated on the suction section 40 side.

[0050] <Description of Modifications> It should be noted that the shapes and the like shown in this embodiment are merely examples, and various modifications and changes are possible within the scope of the gist of the present invention as set forth in the claims. For example, in this embodiment, the shape of the liquid tank 1 is merely an example, and any shape is acceptable as long as it utilizes the principle of a siphon.

[0051] Furthermore, in this embodiment, an example has been shown in which all of the first earth wire 6, second earth wire 7, and third earth wire 10 are used, but this is not limiting, and as long as it is possible to sufficiently neutralize the potential of static electricity generated inside the siphon tube 4, only the first earth wire 6 and second earth wire 7 may be used, or if only the third earth wire 10 is sufficient, only the third earth wire 10 may be used. Note that if only the third earth wire 10 is used, the earth wire mounting plate 9 is not necessary.

[0052] Furthermore, in this embodiment, an example has been shown in which the tip surface 40b of the suction portion 40 is machined into a bell-mouth shape, but this is not limiting and any shape may be used. However, machining into a bell-mouth shape is preferable. This is because a bell-mouth shape provides a wide inlet when the liquid L contained in the liquid tank body 2 is sucked into the siphon tube 4, thereby reducing turbulence of gas-liquid mixture and thereby decreasing the electrification rate of the liquid L.

[0053] Furthermore, in this embodiment, an example has been shown in which the suction part 40 is provided on the underside 4b of the siphon tube 4, but this is not limiting, and if it is not possible to provide the suction part 40, the underside 4b of the siphon tube 4 may be extended. In this case, the suction part becomes the underside 4b of the siphon tube 4, and the third earth wire 10 is essential for fixing the earth wire.

[0054] In addition, in this embodiment, an example has been shown in which the first earth wire 6 and the second earth wire 7 are connected to each other, but this is not limiting, and they do not have to be connected to each other. However, it is preferable that they be connected to each other, as this makes it easier to arrange the first earth wire 6 and the second earth wire 7. [Explanation of symbols]

[0055] 1 liquid tank 2 Liquid tank body 4 Siphon tube 4a Top surface (discharge part) 40 Suction part 40b Tip surface (tip) 6 First ground wire 7 Second ground wire 10 Third ground wire (ground wire) 12 Iron core L liquid CB Clean Booth (designated location) H2 Second supply / drain hose (drain pipe) F7 Lining

Claims

1. a liquid tank body that contains liquid; a siphon pipe provided within the liquid tank body and extending vertically; a drain pipe for discharging the liquid discharged from the siphon pipe to a predetermined location, The siphon tube is a suction section that sucks the liquid contained in the liquid tank body into the siphon tube; a discharge part that discharges the liquid sucked into the siphon tube to the outside of the siphon tube, The suction part is provided with a first earth wire, a second ground wire is provided between the discharge portion and the drain pipe; an iron core lined with a fluororesin is provided on the upper side of the suction part and on the outer peripheral surface of the siphon tube; The liquid tank is provided with a third earth wire connecting the suction portion and the iron core.

2. 2. The liquid tank according to claim 1, wherein the first ground wire and the second ground wire are provided in a continuous manner.

3. 3. The liquid tank according to claim 1, wherein the suction portion has a tip formed in a bell-mouth shape.

4. a liquid tank body that contains liquid; A cylinder is provided in the liquid tank body and extends vertically. With the phone tube, a drain pipe for discharging the liquid discharged from the siphon pipe to a predetermined location, The siphon tube is a suction section that sucks the liquid contained in the liquid tank body into the siphon tube; a discharge part that discharges the liquid sucked into the siphon tube to the outside of the siphon tube, an iron core lined with a fluororesin is provided above the suction part and on the outer circumferential surface of the siphon pipe; The liquid tank is provided with a ground wire connecting the suction portion and the iron core.

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