Air vent device

Abstract

To provide an air ventilation device not deteriorating an operation of a float valve body even when an air valve for a water pipe is used for liquid mixed with foreign matter.SOLUTION: An air ventilation device installed in a liquid transportation pipeline, through which liquid is transported, or in a liquid storage for storing the liquid comprises: a tubular casing divided by a diaphragm deformed with pressure to have a casing upper chamber and a casing lower chamber; a tubular air hole for communicating between the casing lower chamber and the outside of the casing; a pressure equalization pipe coupling the casing lower chamber with the casing upper chamber and having an overflow part; a connection pipeline coupling a side face of the casing upper chamber at a position lower than a connection part of the pressure equalization pipe and the casing upper chamber with an upper part of the liquid transportation pipeline or the liquid storage. The diaphragm can close an opening of the casing lower chamber of the air hole at the time of deformation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an air vent device, and more particularly to an air vent device that is installed in a liquid transport pipe or a liquid storage tank and that has a configuration in which a sealing portion is isolated from the liquid. [Background technology]

[0002] Air may enter a pipe used to transport a liquid such as water from the outside into the pipe. If the air that has entered the pipe remains there, the flow path of the pipe becomes narrow. Air may also enter a tank that stores a liquid from the outside into the pipe. If the air that has entered the pipe remains there, the amount of liquid that can be transported through the pipe decreases. If the air that has entered the tank remains there, the amount of liquid that can be stored in the tank decreases. When air enters the pipe or the like from the outside and remains there, a problem occurs in that the pipe or the tank cannot be used effectively.

[0003] In order to prevent air from accumulating inside pipes, etc., it is necessary to perform so-called "air venting," which discharges the air accumulating inside the pipes, etc. Generally, air venting is performed by providing an air vent valve at the top of the pipe or storage tank where the air is accumulating, and having an operator operate the air vent valve.

[0004] However, if the piping is long and there are many points in the piping that require air venting, it is necessary to use an automatic air venting device that can perform air venting automatically to vent the air at many points.Similarly, if the storage tank is large and there are many points in the storage tank that require air venting, it is also necessary to vent the air at many points.

[0005] In particular, when installing new piping, for example, when circulating a liquid inside a piping that has been emptied due to construction work, it is necessary to discharge a large amount of air that has accumulated inside the piping to the outside. Moreover, there are cases where air needs to be vented at the same time from many points in the piping that require air venting. For this reason, it is desirable to use an automatic air venting device to automatically vent the air that has accumulated inside the piping without manual intervention, in order to simultaneously vent the air from many points in the piping that require air venting.

[0006] From this perspective, an automatic air vent device has been proposed that is resistant to clogging with foreign matter such as dust and is easy to maintain (for example, Patent Document 1). The air valve for water pipes described in Patent Document 1 is known to have a structure in which a float valve element floats up inside the casing, blocking the air hole at the top of the casing and sealing the air hole.

[0007] The air valve for a water supply pipe described in Patent Document 1 includes a valve cover connected to a water supply pipe, a first opening provided in the valve cover and communicating the upper and lower parts of the valve cover, a first sliding body slidably provided in the first opening and having a second opening communicating the upper and lower parts of the first opening, a second sliding body slidably provided in the second opening, a float provided below the second sliding body, a first air passage formed outside the second opening and communicating the upper and lower parts of the valve cover, a second air passage formed inside the second opening and communicating the upper and lower parts of the valve cover, a first valve body that blocks communication through the first air passage, and a second valve body that blocks communication through the second air passage.This air valve for a water supply pipe has a simple structure for the parts that are immersed in water, making it less likely to become clogged with foreign matter such as dust, facilitating maintenance, and allowing the air passage to be formed in a straight line, resulting in a simpler structure. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-222214 Summary of the Invention [Problem to be solved by the invention]

[0009] However, the above-mentioned conventional technology still has the following problems to be solved. That is, the air valve for water supply pipes described in Patent Document 1 removes air by automatically discharging the air by moving the float valve body up and down depending on whether or not there is air trapped inside the pipe, etc., thereby saving the operator the trouble of operating the float valve body. On the other hand, when the air valve for water supply pipes is used for liquids containing foreign matter, such as sewage, there is a problem that the float valve body may not function properly or the sealing performance of the seal may be impaired, resulting in malfunction of the float valve body.

[0010] The present invention has been made in consideration of the above circumstances, and aims to provide an air vent device that will not cause deterioration in the operation of the float valve body, even when an air valve for a water supply pipe is used for liquid containing foreign matter, by isolating the seal part from the liquid so that the seal part does not come into direct contact with the liquid. [Means for solving the problem]

[0011] Therefore, the inventor conducted various experiments to solve the above problem, and as a result, discovered that by isolating the seal from the liquid so that it does not come into direct contact with the liquid, the float will not malfunction and the sealing performance of the seal will not be impaired even if liquid containing foreign matter such as sewage is transported through a pipe or stored in a storage tank. The present invention was made based on the above findings, and its gist is as follows.

[0012] That is, the air vent device of the present invention, which advantageously solves the above-mentioned problems, is an air vent device installed in a liquid transport pipe through which a liquid is transported or in a liquid storage tank in which the liquid is stored, and comprises: a cylindrical casing having an upper casing chamber and a lower casing chamber divided by a diaphragm that deforms under pressure; a tubular air hole that connects the lower casing chamber to the outside of the casing; a pressure equalizing pipe that connects the lower casing chamber to the upper casing chamber and has an overflow section; and a connecting pipe that connects a side of the upper casing chamber that is lower than the connection between the pressure equalizing pipe and the upper casing chamber to the liquid transport pipe or the top of the liquid storage tank, and is characterized in that the diaphragm is capable of closing the opening of the air hole in the lower casing chamber when it is deformed.

[0013] The air vent device according to the present invention is (a) the overflow section is installed at a position higher than the liquid level of the liquid present inside the liquid transport pipe or the liquid storage tank when the liquid flows into the casing upper chamber; (b) The position of the liquid level is determined at a time t when the liquid present in the liquid transport pipe or the liquid storage tank flows into the upper casing chamber, causing the diaphragm to deform toward the lower casing chamber and closing the air hole. i The volume of air present in the air vent device at the initial volume V i and the initial volume V i When the air is pressurized to the pressure of the liquid present inside the liquid transport pipe or the liquid storage tank, the volume after pressurization is V p When the initial volume V i and the volume after pressurization V p The volume difference V i -V p It is considered that a more preferable solution is to set the liquid level to the level when the liquid corresponding to the above-mentioned amount flows into the casing upper chamber. [Effects of the Invention]

[0014] The air vent device according to the present invention is structured so that when liquid flows into the casing upper chamber located above the diaphragm inside the casing, the diaphragm deforms downward, blocking the air hole in the diaphragm lower chamber located below the diaphragm. Therefore, with the air vent device according to the present invention, there is no risk of the float malfunctioning.

[0015] Furthermore, the air vent device according to the present invention is isolated from the liquid so that the air holes and seals do not come into direct contact with the liquid, and therefore foreign matter contained in the liquid does not get caught in it, the airtightness of the seals is less likely to be impaired, and poor sealing of the seals is less likely to occur. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view showing an overview of an air vent device according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view showing a state in which the air present inside a casing provided in the air vent device according to the present embodiment has stopped circulating to the outside of the casing. FIG. [Figure 3-1] 4 is a cross-sectional view showing an example of an overflow section of a pressure equalizing pipe provided in the air vent device according to the present embodiment. FIG. [Figure 3-2] 4 is a cross-sectional view showing an example of an overflow section of a pressure equalizing pipe provided in the air vent device according to the present embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] [First embodiment] An air vent device according to a first embodiment will be described. The air vent device according to this embodiment is installed in a liquid transport pipe through which a liquid is transported or in a liquid storage tank in which the liquid is stored. The air vent device according to this embodiment includes a cylindrical casing having an upper casing chamber and a lower casing chamber divided by a diaphragm that deforms under pressure, a tubular air hole that connects the lower casing chamber to the outside of the casing, a pressure equalizing pipe that connects the lower casing chamber to the upper casing chamber and has an overflow portion, and a connecting pipe that connects a side surface of the upper casing chamber that is lower than the connection portion between the pressure equalizing pipe and the upper casing chamber to the liquid transport pipe or the top of the liquid storage tank, and the diaphragm is capable of closing the opening of the air hole in the lower casing chamber when it deforms. Hereinafter, each member of the air vent device according to this embodiment will be described with reference to the drawings.

[0018] FIG. 1 is a cross-sectional view showing an outline of an air vent device according to this embodiment. As shown in FIG. 1, air vent device 100 according to this embodiment includes a casing 101. Casing 101 has an upper casing chamber 111 and a lower casing chamber 112 divided by a diaphragm 102. Air vent device 100 includes a tubular air hole 103 that connects lower casing chamber 112 to the outside of casing 101, and a pressure equalizing pipe 104 that connects lower casing chamber 112 to upper casing chamber 111. Air vent device 100 also includes a connecting pipe 105 that connects an outer casing surface 114, which is on a side surface of upper casing chamber 111 and is located lower than a connecting portion 113 between pressure equalizing pipe 104 and upper casing chamber 111, to an upper portion of liquid transport pipe 200 in which air vent device 100 is installed.

[0019] The air vent device 100 according to this embodiment is installed in the liquid transport pipe 200. The air vent device 100 is connected to the liquid transport pipe 200. The upper end 151 of the connection pipe 105 is connected to the casing upper chamber 111, and the lower end 152 of the connection pipe 105 is connected to the upper part of the liquid transport pipe 200, thereby connecting the air vent device 100 to the liquid transport pipe 200. The upper part of the liquid transport pipe 200 is not filled with the liquid L to be transported, but is filled with air G that has entered from outside the liquid transport pipe 200. For this reason, the air vent device 100 is used to discharge the air G that has accumulated in the upper part of the liquid transport pipe 200 to the outside of the liquid transport pipe 200.

[0020] The air vent device 100 according to this embodiment may be installed not only in the liquid transport pipe 200, which is the pipe through which the liquid L is transported, but also in a liquid storage tank (not shown) in which the liquid L is stored. Here, an embodiment in which the air vent device 100 is installed in the liquid transport pipe 200 will be described.

[0021] In the air venting device 100 according to this embodiment, the liquid L transported by the liquid transport piping 200 in which the air venting device 100 is installed or the liquid L stored in the liquid storage tank may be in a liquid state, and may be not only a liquid but also a slurry containing minerals, sludge, etc. Specifically, examples of the liquid L transported by the liquid transport piping 200 or the liquid L stored in the liquid storage tank include water, liquids containing foreign matter such as wastewater or sewage, crude oil, liquid fuel, etc.

[0022] The air vent device 100 includes a casing 101. The casing 101 has a cylindrical shape, preferably a cylindrical shape. The casing 101 is composed of an upper casing chamber 111 located above the casing 101 and a lower casing chamber 112 located below the casing 101. The material constituting the casing 101 may be any material that has excellent pressure resistance, durability, and processability, and may be composed of, for example, polyethylene resin, ethylene-vinyl alcohol copolymer, stainless steel, aluminum alloy, or steel.

[0023] The casing 101 has a diaphragm 102 therein. The diaphragm 102 divides the interior of the casing 101 into an upper casing chamber 111 located above the casing 101 and a lower casing chamber 112. The diaphragm 102 is deformable toward the lower casing chamber 112 due to pressure received from the upper casing chamber 111 side that constitutes the casing 101. The diaphragm 102 deforms toward the lower casing chamber 112 due to the weight of the liquid L that flows in from the liquid transport pipe 200 via the connecting pipe 105.

[0024] The diaphragm 102 forms the boundary surface between the casing upper chamber 111 and the casing lower chamber 112. The diaphragm 102 has the function of preventing the flow of liquid L flowing in from the liquid transport pipe 200 via the connecting pipe 105 and the flow of gas flowing in from the air hole 103 in the upper and lower spaces formed by the casing upper chamber 111 and the casing lower chamber 112. The diaphragm 102 has a fixing portion 116 for fixing an edge portion 121 of the diaphragm 102 to the casing inner surface 115. The fixing portion 116 seals the edge portion 121 of the diaphragm 102 to prevent the intrusion of liquid L and gas into the upper and lower space formed from the casing upper chamber 111 and the casing lower chamber 112 sides.

[0025] The diaphragm 102 divides the casing 101 into an upper casing chamber 111 and a lower casing chamber 112. The diaphragm 102 may divide the casing 101 into the upper casing chamber 111 and the lower casing chamber 112 by adopting the following configurations: An upper casing chamber flange 117 is formed by processing the lower end of the upper casing chamber 111 into a flange shape. A lower casing chamber flange 118 is formed by processing the upper end of the lower casing chamber 112 into a flange shape. The diaphragm 102 is sandwiched and fixed between the upper casing chamber flange 117 and the lower casing chamber flange 118.

[0026] Diaphragm 102 is formed of a material that is impermeable to gas G and liquid L. Diaphragm 102 is preferably one that can flexibly deform due to the weight of liquid L that flows into upper casing chamber 111. Diaphragm 102 may have a two-layer structure made of a thin film made of synthetic resin such as polyethylene terephthalate (PTFE) and a thin rubber film made of rubber such as ethylene propylene diene rubber (EPDM) or fluororubber (FKM). A two-layer structure made of a thin film made of synthetic resin and a thin rubber film is preferable because diaphragm 102 can flexibly deform due to the weight of liquid L that flows into upper casing chamber 111 that constitutes casing 101.

[0027] The air vent device 100 includes an air hole 103. The air hole 103 is disposed in the casing bottom 119 of the casing lower chamber 112. The air hole 103 may have any shape as long as it allows the air G flowing in via the pressure equalizing pipe 104 to pass through, and may have, for example, a tubular structure. The air hole 103 communicates between the interior of the casing lower chamber 112 and the outside of the casing 101. The air hole 103 has an upper end opening 131 and a lower end opening 132. The annular upper end opening 131 located at the upper end of the air hole 103 faces the diaphragm lower surface 123 of the diaphragm 102. The annular lower end opening 132 located at the lower end of the air hole 103 faces the outside of the casing 101. The lower end opening 132 located at the lower end of the air hole 103 is open to the outside of the casing 101. Therefore, the pressure inside the casing lower chamber 112 is equal to atmospheric pressure.

[0028] When diaphragm 102 deforms convexly toward casing lower chamber 112 located below casing 101, upper end opening 131 located at the upper end of air hole 103 comes into close contact with diaphragm lower surface 123 of diaphragm 102. In this manner, air hole 103 is disposed opposite diaphragm 102 so that upper end opening 131 located at the upper end of air hole 103 can be closed. The diameter of air hole 103 is preferably 1 / 2 to 1 / 4 of the diameter of casing 101, and particularly preferably 1 / 3.

[0029] When diaphragm lower surface 123 of diaphragm 102 is in close contact with upper end opening 131 of air hole 103, completely sealing said air hole 103, diaphragm upper surface 122 of diaphragm 102 is subjected to pressure from upper casing chamber 111. Meanwhile, the surface of diaphragm lower surface 123 of diaphragm 102 facing lower end opening 132 located at the lower end of air hole 103 is subjected to atmospheric pressure. Furthermore, the surface of diaphragm lower surface 123 of diaphragm 102 that is outside lower end opening 132 located at the lower end of air hole 103 is subjected to pressure from lower casing chamber 112. Therefore, when the pressures in upper casing chamber 111 and lower casing chamber 112 are equal and equal to or greater than atmospheric pressure, the larger the area of ​​air hole 103, the smaller the area of ​​diaphragm lower surface 123 that is subjected to pressure from lower casing chamber 112. As a result, the diaphragm 102 is pressed firmly against the upper end opening 131 of the air hole 103 to which the diaphragm 102 is in close contact.

[0030] The air vent device 100 is equipped with a pressure equalizing pipe 104. The pressure equalizing pipe 104 connects the upper casing chamber 111 of the casing 101 to the lower casing chamber 112 of the casing 101. An upper end 142 of the pressure equalizing pipe 104 is preferably connected to the upper surface of the upper casing chamber 111. A lower end 143 of the pressure equalizing pipe 104 is preferably connected to the side surface of the lower casing chamber 112. The pressure equalizing pipe 104 is configured so that air G that has flowed in from the liquid transport piping 200 via the connecting piping 105 can move from the upper casing chamber 111 to the lower casing chamber 112. The position at which the pressure equalizing pipe 104 and the upper casing chamber 111 of the casing 101 are connected is preferably higher than the position at which the upper casing chamber 111 of the casing 101 and the connecting piping 105 are connected. The position where the pressure equalizing pipe 104 and the lower casing chamber 112 of the casing 101 are connected is preferably lower than the position where the upper casing chamber 111 of the casing 101 and the connecting pipe 105 are connected.

[0031] The air vent device 100 is equipped with a connecting pipe 105. The connecting pipe 105 is located below the upper casing chamber 111 and above the lower casing chamber 112, and connects the casing 101 to the liquid transport pipe 200. The connecting pipe 105 has one end thereof connected to the upper casing chamber 111 and the other end thereof connected to the liquid transport pipe 200. That is, the connecting pipe upper end 151 of the connecting pipe 105 is connected to the vicinity of the lower part of the upper casing chamber 111 of the casing 101. Furthermore, the connecting pipe lower end 152 of the connecting pipe 105 is connected to the vicinity of the upper part of the liquid transport pipe 200. The connecting pipe 105 allows the liquid L stored inside the liquid transport pipe 200 and the air G stagnating inside the liquid transport pipe 200 to flow into the upper casing chamber 111 of the casing 101.

[0032] Below, we will explain the mechanism by which air G that has accumulated inside the liquid transport piping 200 through which the liquid L flows in the air purge device 100 according to this embodiment is discharged to the outside of the liquid transport piping 200. We will also explain the mechanism by which, after the air G that has accumulated inside the liquid transport piping 200 is discharged to the outside of the liquid transport piping 200, the air G is sealed to prevent it from re-entering the casing 101.

[0033] 1 shows a state I in which liquid L is flowing inside a liquid transport pipe 200 in which an air purge device 100 according to this embodiment is installed, and air G is accumulating in the upper part of the liquid transport pipe 200. This state I can occur when air G has entered the liquid transport pipe 200, for example, when liquid L is newly supplied to the liquid transport pipe 200 that has been emptied due to repair of the liquid transport pipe 200 or installation of a new liquid transport pipe 200.

[0034] When liquid L at a pressure higher than atmospheric pressure is circulated through the liquid transport pipe 200 from a state I in which air G is stagnating inside the liquid transport pipe 200, the air G stagnating inside the liquid transport pipe 200 is pushed out into the upper casing chamber 111 of the casing 101 via the connecting pipe 105. The air G pushed out from the upper casing chamber 111 passes through the pressure equalizing pipe 104 and the lower casing chamber 112 and is discharged from the air hole 103.

[0035] Next, when the air G remaining inside the liquid transport pipe 200 is discharged through the air hole 103, liquid L equivalent to the volume of the air G discharged through the air hole 103 flows from the liquid transport pipe 200 into the connecting pipe 105 (flowing in the direction of the arrow). The liquid L that has flowed from the liquid transport pipe 200 into the connecting pipe 105 flows into the upper casing chamber 111 of the casing 101. The liquid L that has flowed into the upper casing chamber 111 flows into the diaphragm upper surface 122 of the diaphragm 102 that is installed to divide the casing 101 into the upper casing chamber 111 and the lower casing chamber 112.

[0036] As a result, the liquid L that has flowed onto the diaphragm upper surface 122 of the diaphragm 102 causes the central portion C of the diaphragm 102 to deform in a convex shape toward the casing lower chamber 112 located below the casing 101. Therefore, as shown in FIG. 2, the central portion C of the diaphragm 102 comes into contact with the upper end opening 131 of the air hole 103, and the upper end opening 131 of the air hole 103 is completely sealed by the diaphragm lower surface 123 (state II). Finally, the upper end opening 131 of the air hole 103 is completely sealed, and state II is maintained, thereby stopping the flow of air G present inside the casing 101 to the outside of the casing 101. FIG. 2 shows state II in which the flow of air G present inside the casing 101 to the outside of the casing 101 has stopped.

[0037] If the pressure of the liquid L flowing inside the liquid transport pipe 200 is even higher, the liquid level of the liquid L that has flowed into the upper casing chamber 111 of the casing 101 will further rise. When the liquid level of the liquid L that has flowed into the upper casing chamber 111 rises, the air G that is present in the upper casing chamber 111, the pressure equalizing pipe 104, and the lower casing chamber 112 of the casing 101 will be compressed.

[0038] When the air G is compressed, a pressure P1 based on the difference between the liquid level S of the liquid L that has flowed into the casing upper chamber 111 and the position where the connecting pipe lower end 152 of the connecting pipe 105 is connected to the liquid transport pipe 200, and a pressure P2 of the compressed air G, acts on the position where the connecting pipe lower end 152 of the connecting pipe 105 is connected to the liquid transport pipe 200. When the pressure P1 based on the difference between the liquid level S of the liquid L that has flowed into the casing upper chamber 111 and the position where the connecting pipe 105 is connected to the connecting pipe lower end 152 of the liquid transport pipe 200 and the pressure P2 of the compressed air G becomes equal to the pressure of the liquid L present inside the liquid transport pipe 200, the rise of the liquid level S of the liquid L present inside the casing upper chamber 111 of the casing 101 stops.

[0039] Here, when the pressure of the liquid L present inside the liquid transport pipe 200 is high, the liquid L does not stop flowing from the liquid transport pipe 200 into the upper casing chamber 111 of the casing 101. For this reason, the liquid L present in the upper casing chamber 111 may flow into the pressure equalizing pipe 104, and then overflow from the pressure equalizing pipe 104, thereby flowing into the lower casing chamber 112 of the casing 101 as the liquid L that has overflowed from the pressure equalizing pipe 104.

[0040] However, even when the liquid L that has overflowed from the pressure equalizing pipe 104 does not flow into the casing lower chamber 112, or even when the liquid L that has overflowed from the pressure equalizing pipe 104 flows into the casing lower chamber 112, the pressure applied to the diaphragm lower surface 123 does not exceed the pressure applied to the diaphragm upper surface 122.

[0041] In other words, when the liquid L that has overflowed from the pressure equalizing pipe 104 has not flowed into the lower casing chamber 112, there is a load of the liquid L present in the upper casing chamber 111, and therefore a pressure equivalent to that load is applied to the upper diaphragm surface 122 higher than that of the lower diaphragm surface 123. On the other hand, when the liquid L that has overflowed from the pressure equalizing pipe 104 also flows into the lower casing chamber 112, the liquid level of the liquid L that has flowed into the pressure equalizing pipe 104 does not exceed the liquid level of the liquid L present inside the upper casing chamber 111 of the casing 101. Therefore, the pressure applied to the lower surface 123 of the diaphragm 102 is at most equal to the pressure applied to the upper surface 122 of the diaphragm.

[0042] Furthermore, while the entire surface of the diaphragm upper surface 122 of the diaphragm 102 is subjected to pressure, the pressure acting on the diaphragm lower surface 123 of the diaphragm 102 near the center C is atmospheric pressure. The pressure acting on the diaphragm upper surface 122 of the diaphragm 102 is greater than the pressure acting on the diaphragm lower surface 123 of the diaphragm 102. As a result, the diaphragm lower surface 123 of the diaphragm 102 is constantly pressed against the upper end opening 131 of the air hole 103. The diaphragm lower surface 123 of the diaphragm 102 is in close contact with the upper end opening 131 of the air hole 103. As a result, the upper end opening 131 of the air hole 103 is kept completely sealed by the diaphragm lower surface 123 of the diaphragm 102.

[0043] In this way, while the air hole 103 is kept sealed by the diaphragm 102, the air G remaining in the liquid transport pipe 200 flows into the upper casing chamber 111 of the casing 101 via the connecting pipe 105. As the air G flows into the upper casing chamber 111 via the connecting pipe 105, the liquid level S of the liquid L present in the upper casing chamber 111 drops, and the load of the liquid L acting on the diaphragm upper surface 122 of the diaphragm 102 is reduced. As a result, the diaphragm lower surface 123 of the diaphragm 102 moves away from the upper end opening 131 of the air hole 103, and some of the air G present inside the air vent device 100 is discharged to the outside of the air vent device 100. Furthermore, if liquid L is present in the lower casing chamber 112, the air G and liquid L present inside the air vent device 100 are discharged to the outside of the air vent device 100.

[0044] In this way, the air G present inside the air vent device 100 is discharged to the outside of the air vent device 100, and liquid L flows into the upper casing chamber 111 of the casing 101 in an amount corresponding to the volume of the discharged air G. The liquid L flowing into the upper casing chamber 111 again deforms the diaphragm 102 into a convex shape toward the lower casing chamber 112, and the diaphragm 102 adheres tightly to the upper end opening 131 of the air hole 103, completely sealing the air hole 103.

[0045] If the pressure of the liquid L present inside the liquid transport pipe 200 is slightly higher than atmospheric pressure, it is possible to employ a known liquid sealing structure to vent the air G present inside the liquid transport pipe 200 without using the air vent device 100 according to this embodiment. Specifically, if the pressure of the liquid L present inside the liquid transport pipe 200 is about 0.5 atmospheres higher than atmospheric pressure, an air vent pipe is erected upward from the top of the liquid transport pipe 200 through which the fluid L flows. Then, the air hole 103 can be sealed by the pressure of the liquid column inside the erected pipe.

[0046] However, the air venting device 100 of this embodiment has an excellent technical feature in that even when the pressure inside the liquid transport piping 200 is high, the diaphragm 102 effectively seals the air hole 103, effectively preventing the liquid L from flowing out of the liquid transport piping 200, while discharging the air G present in the liquid transport piping 200, thereby performing air venting.

[0047] As described above, according to the invention of the first embodiment, by isolating the seal portion from the liquid so that it does not come into direct contact with the liquid, it is possible to provide an air vent device in which the float does not operate poorly even when liquid containing foreign matter such as sewage is transported through the liquid transport piping, and in which the airtightness of the seal portion formed by the diaphragm and air hole is not impaired.

[0048] [Second embodiment] An air vent device according to a second embodiment will now be described. The air vent device according to this embodiment is characterized in that, in the above-described air vent device, the overflow section is installed at a position higher than the liquid level of the liquid present in the liquid transport pipe or the liquid storage tank when the liquid flows into the casing upper chamber. That is, the air vent device 100 according to this embodiment has a configuration for preventing the flow of liquid L from the liquid transport pipe 200 into the casing lower chamber 112.

[0049] In the air purge device 100 according to the above embodiment, even if liquid L flows into the casing lower chamber 112, the diaphragm 102 still functions to seal the air hole 103. Therefore, there is no problem in discharging the air G present inside the liquid transport pipe 200.

[0050] However, when the air G present inside the liquid transport pipe 200 is discharged to the outside, the liquid L accumulated in the lower casing chamber 112 may flow out of the air purge device 100. For this reason, it may be more preferable to prevent the liquid L from entering the lower casing chamber 112. In particular, if the liquid L contains solid matter, the solid matter may become trapped between the diaphragm 102 and the end of the air hole 103, making it impossible to maintain the seal of the air hole 103. From this technical perspective, it is also preferable to prevent the liquid L from entering the lower casing chamber 112. Therefore, by adopting the following configuration, the air purge device 100 according to this embodiment can prevent the liquid L from flowing into the lower casing chamber 112 and discharge the air G present inside the liquid transport pipe 200.

[0051] 3-1 and 3-2 are cross-sectional views showing an example of an overflow section of a pressure equalizing pipe included in the air vent device according to this embodiment. As shown in FIG. 3-1(a), an upper end 142 of a pressure equalizing pipe 104 included in the air vent device 100 according to this embodiment is connected to the casing ceiling 101T of the casing 101. A lower end 143 (not shown) of the pressure equalizing pipe 104 is connected to the casing lower chamber 112 of the casing 101. The pressure equalizing pipe 104 has an overflow section 141A formed by extending vertically upward from the casing ceiling 101T of the casing 101, bending approximately 90° from the highest point of the pressure equalizing pipe 104, and maintaining the same horizontal position. In FIG. 3-1(a), the overflow section 141A is indicated by a bold line.

[0052] Similarly, as shown in Fig. 3-1(b), the upper end 142 of the pressure equalizing pipe 104 is connected to the casing ceiling 101T of the casing 101. The pressure equalizing pipe 104 has an overflow portion 141B formed by extending upward from the casing ceiling 101T of the casing 101 at an angle of approximately 45° and bending downward at an acute angle starting from the highest point of the pressure equalizing pipe 104. In Fig. 3-1(b), the overflow portion 141B is indicated by a black circle.

[0053] Furthermore, as shown in Fig. 3-2(c), the upper end 142 of the pressure equalizing pipe 104 is connected to the casing side surface 101S of the casing 101. The pressure equalizing pipe 104 extends horizontally from the casing side surface 101S of the casing 101 to form a horizontal portion, and then bends downward at an angle of 90 degrees to form an overflow portion 141C. In Fig. 3-2(c), the overflow portion 141C is indicated by a thick line.

[0054] Furthermore, as shown in Fig. 3-2(d), an upper end 142 of the pressure equalizing pipe 104 is connected to the casing side surface 101S of the casing 101. The pressure equalizing pipe 104 has an overflow portion 141D formed by extending upward from the casing side surface 101S of the casing 101 at an angle of approximately 45° and bending downward at an acute angle with the highest point of the pressure equalizing pipe 104 as a fulcrum. In Fig. 3-2(d), the overflow portion 141D is indicated by a black circle.

[0055] As described above, the air vent device 100 according to this embodiment has overflow sections 141A to D in the pressure equalizing pipe 104. These overflow sections 141A to D are all installed at positions higher than the position to which the liquid level S of the liquid L rises. Therefore, the air vent device 100 according to this embodiment can effectively prevent the liquid L that has flowed in from the liquid transport piping 200 from flowing into the casing lower chamber 112. The shape of the overflow sections provided in the pressure equalizing pipe 104 is not limited to the overflow sections 141A to D, and can be set appropriately depending on the shapes of the casing 101, the casing upper chamber 111, the casing lower chamber 112, and the pressure equalizing pipe 104.

[0056] As described above, according to the invention of the second embodiment, it is possible to provide an air vent device that can discharge air present inside the liquid transport piping to the outside without liquid L flowing into the casing lower chamber 112 from the liquid transport piping 200.

[0057] [Third embodiment] An air vent device according to a third embodiment will now be described. The air vent device according to this embodiment is characterized in that the height to which the liquid level rises after the diaphragm seals the air hole is determined by a predetermined method. In the air vent device of this embodiment, the height to which the liquid level rises after the diaphragm seals the air hole can be calculated by experiment, but the following method can also be used as a simple calculation method.

[0058] First, the initial volume V of the air remaining inside the air vent device 100 is calculated from the position of the liquid level S of the liquid L when the diaphragm 102 deforms downward and starts to seal the air hole 103. i Next, the pressurized volume V when the air is pressurized to the pressure of the liquid L in the liquid transport pipe 200 is calculated. p Here, the pressure of the air remaining inside the air vent device 100 does not exceed the pressure of the liquid L in the liquid transport pipe 200. Therefore, the pressurized volume V p is the volume of air when it is most compressed.

[0059] At this time, the initial volume V i and pressurized volume V p The difference between the volume (V i -V p ) can be considered as the volume of air compressed by the inflow of the liquid L from the liquid transport pipe 200 into the upper casing chamber 111 of the casing 101. Therefore, the volume of the liquid in the upper casing chamber 111 of the casing 101 when the diaphragm 102 begins to seal the air hole 103 is multiplied by the initial volume V i and the above pressurized volume V p The difference between the volume (V i -V p ) is the maximum volume Vmax of the liquid L that flows into the upper casing chamber 111 of the casing 101.

[0060] If the maximum volume of liquid L flows into the upper casing chamber 111 of the casing 101, the liquid L will not flow into the lower casing chamber 112 if the height of the liquid level S of the liquid L in the upper casing chamber 111 is lower than the height of the overflow portion 141 in the pressure equalizing pipe 104. In other words, by setting the height of the liquid level S of the liquid L in the casing 101 to be lower than the height of the overflow portion 141 in the pressure equalizing pipe 104 when the maximum volume Vmax of liquid L flows into the casing 111 of the casing 101, it is possible to prevent the liquid L from flowing into the lower casing chamber 112.

[0061] That is, in the air vent device 100 according to this embodiment, the volumes of the casing upper chamber 111, the casing lower chamber 112, and the pressure equalizing pipe 104, and the shape of the pressure equalizing pipe 104 may be determined so that the height of the liquid level S of the liquid L in the casing upper chamber 111 is lower than the height of the overflow section 141 in the pressure equalizing pipe 104. When determining the volumes of the casing upper chamber 111, the casing lower chamber 112, and the pressure equalizing pipe 104, and the shape of the pressure equalizing pipe 104, they may be determined with some leeway in consideration of the design specifications of the air vent device 100, variations in the conditions of use, and the like. For example, in the air vent device 100, if the volume of the pressure equalizing pipe 104 is large, even if the inflow rate of liquid L increases and the liquid level S rises, if the decrease in volume due to the inflow of liquid L is small compared to the volume of the pressure equalizing pipe 104, the pressure rise is small and the rise of the liquid level S is unlikely to stop. Furthermore, in the air vent device 100, if the diameter of the casing 101 decreases toward the top, the pressure of the sealed air G is more likely to rise even with the same inflow rate of liquid L than if the diameter of the casing 101 is constant at the top and bottom. That is, taking into account the rise in the liquid level S and the pressure of the sealed air G due to the design specifications of the air vent device 100 according to this embodiment, the height of the liquid level S of the liquid L in the casing upper chamber 111 may be set to be lower than the height of the overflow portion 141 in the pressure equalizing pipe 104.

[0062] The level of liquid L at the time when diaphragm 102 deforms downward and begins to seal air hole 103 can be estimated based on the load on the top of diaphragm 102 at that time and the deformability of diaphragm 102, which is determined by the material, thickness, etc. of diaphragm 102. The level of liquid L at the time when diaphragm 102 deforms downward and begins to seal air hole 103 may also be determined by experiment.

[0063] In this way, the air vent device 100 according to this embodiment can determine, by a simple method, the height to which the liquid level S of the liquid L will rise after the diaphragm 102 seals the air hole 103. The air vent device 100 according to this embodiment can prevent the liquid L from flowing into the lower casing chamber 112 by setting the height of the liquid level S of the liquid L in the casing 101 when the liquid L has a maximum volume Vmax flowing into the upper casing chamber 111 of the casing 101 to be lower than the height of the overflow section 141 in the pressure equalizing pipe 104.

[0064] As described above, according to the invention of the third embodiment, by using the air vent device of the above embodiment, the position of the liquid surface at the time when the diaphragm begins to seal the air hole can be determined by a simple method, thereby realizing the venting of air present inside the liquid transport piping without liquid flowing into the lower chamber of the casing.

[0065] [Other embodiments] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above embodiments. Various modifications can be made to the configuration and details of the present invention that are understandable to those skilled in the art within the technical scope of the present invention. Furthermore, systems or devices that combine the separate features included in each embodiment in any manner are also included in the technical scope of the present invention. [Example]

[0066] The effects of the present invention will be specifically explained below based on examples, but the present invention is not limited to these examples.

[0067] Example 1 The air venting device 100 according to the present invention was used to vent air present inside the liquid transport piping 200. Specifically, the air venting device according to the present invention was installed in an arrangement as shown in Fig. 1 on an 800A liquid transport piping that supplies wastewater at a pressure of 0.5 MPa, and the air was vented from the liquid transport piping 200.

[0068] Here, the diameter of the cylindrical steel casing 101 provided in the air vent device 100 was set to Φ300 mm, the height of the upper casing chamber 111 to 500 mm, and the height of the lower casing chamber 112 to 50 mm. Furthermore, the connecting pipe 105 connecting the liquid transport pipe 200 and the upper casing chamber 111 was set to 50A, and the hole diameter of the air hole 103 was set to Φ100 mm and its height was set to 30 mm. The pressure equalizing pipe 104 was a steel pipe with a diameter of 20 mm, which was raised 50 mm from the ceiling of the casing 101, bent horizontally, and then bent downward to connect to the side of the lower casing chamber 112. The diaphragm 102 had a two-layer structure consisting of a thin film made of polyethylene terephthalate (PTFE) and a thin rubber film made of ethylene propylene diene rubber (EPDM), and was installed so that the side in contact with the seal was the thin film made of polyethylene terephthalate (PTFE).

[0069] The supply of wastewater to the liquid transport pipe 200 was started, and it was detected that air was being discharged from the air hole 103. Thereafter, when the wastewater accumulated in the casing upper chamber 111 to a height of approximately 330 mm, the air hole 103 was sealed by a thin film made of polyethylene terephthalate (PTFE) constituting the diaphragm 102. Then, when the wastewater flowing into the pipe reached near the ceiling of the casing 101, the rise in the wastewater level stopped. Thereafter, the air vent device 100 maintained a state in which the air hole 103 was sealed by the diaphragm 102.

[0070] As described above, the air vent device according to the present invention is structured so that when liquid flows into the upper casing chamber located above the diaphragm provided inside the casing, the diaphragm deforms downward, blocking the air hole provided in the lower casing chamber located below the diaphragm. Therefore, it has become clear that the air vent device according to the present invention does not cause malfunction of the float. [Industrial Applicability]

[0071] According to the air vent device of the present invention, the diaphragm installed inside the casing deforms to block the air hole installed in the lower chamber of the casing, thereby making it possible to vent air present in liquid transport piping, etc., which contributes to the development of related industries such as the steelmaking industry and is extremely useful industrially. [Explanation of symbols]

[0072] 100 Air vent device 101 Casing 101T Casing ceiling 101S Casing side 102 diaphragm 121 Edge 122 Diaphragm top 123 Underside of diaphragm 111 Casing upper chamber 112 Casing lower chamber 113 Connection 114 Casing outer surface 115 Casing inner surface 116 Fixed part 117 Casing upper chamber flange 118 Casing lower chamber flange 119 Casing bottom 103 Air vent 131 Upper end opening (diaphragm lower chamber side) 132 Lower end opening (outside of casing) 104 Pressure equalization pipe 141 Overflow section 141A Overflow section 141B Overflow Section 141C Overflow section 141D Overflow Section 142 Upper end of the equalizing tube 143 Lower end of the equalizing tube 105 Connection and piping 151 Connect the upper end of the piping 152 Connect the lower end of the piping 200 Liquid transfer piping L liquid G empty

Claims

1. An air vent device installed in a liquid transport pipe through which a liquid is transported or in a liquid storage tank in which the liquid is stored, a cylindrical casing having an upper casing chamber and a lower casing chamber divided by a diaphragm that deforms under pressure; a tubular air hole that connects the lower chamber of the casing with the outside of the casing; a pressure equalizing pipe connecting the lower casing chamber and the upper casing chamber and having an overflow portion; a connecting pipe that connects a side surface of the casing upper chamber, the side surface being lower than a connection portion between the pressure equalizing pipe and the casing upper chamber, to the liquid transport pipe or an upper portion of the liquid storage tank, The diaphragm is capable of closing the opening of the air hole in the casing lower chamber when deformed.

2. The air vent device according to claim 1, wherein the overflow section is installed at a position higher than the liquid level of the liquid present inside the liquid transport pipe or the liquid storage tank when the liquid flows into the casing upper chamber.

3. The position of the liquid level is determined at a time t when the liquid present in the liquid transport pipe or the liquid storage tank flows into the upper casing chamber, causing the diaphragm to deform toward the lower casing chamber, and the air hole begins to close. ｉ The volume of air present in the air vent device at the initial volume V ｉ year, The initial volume V ｉ When the air is pressurized to the pressure of the liquid present inside the liquid transport pipe or the liquid storage tank, the volume after pressurization is V ｐ When The initial volume V ｉ and the volume after pressurization V ｐ The volume difference V ｉ -V ｐ 3. The air vent device according to claim 2, wherein the liquid level is a level of the liquid when the liquid corresponding to the liquid level flows into the upper casing chamber.

Images