Mechanical seal with valve

Abstract

To provide a non-contact mechanical seal. [Solution] The mechanical seal 100 is provided which increases the internal pressure around the shaft insertion portion 120 inside the first retaining air chamber 170 by the gas discharged into the first retaining air chamber 170, moves the first valve portion 130 by the pressure difference between the internal pressure of the first retaining air chamber 170 and the internal pressure of the first valve adjustment air chamber 150, adjusts the width of the first clearance C, and adjusts the airflow rate of the gas discharged from the first clearance C.

Description

Technical Field

[0001] The present invention relates to a mechanical seal having a valve.

Background Art

[0002] Filling of powders such as wheat flour, powdered feed, and mineral powder into a packaging bag by a powder bagging machine is performed by holding the packaging bag in an upright state and inserting a supply pipe into the valve opening of the packaging bag.

[0003] And although a screw or the like is used to fill the powder, there is a risk that the powder may enter from the powder area side into the drive part area side of the screw.

[0004] In Patent Document 1, a mechanical seal is disclosed which has a high degree of design freedom and is less likely to leak even when back pressure occurs.

[0005] Specifically, it is a mechanical seal 1 that seals around the rotating shaft by sliding contact between a rotating ring 16 fixed to the rotating shaft S and a stationary ring 8 through which the rotating shaft passes, and includes a sealing portion 24 that seals between a rotating ring or a stationary ring side member biased by a biasing device and a member on the main body side or the rotating shaft side. The sealing portion has a main seal ring 20 and a dust cut seal ring 22 arranged in parallel with the main seal ring inside the machine. The main seal ring is formed on a rotating ring or a stationary ring side member and is accommodated in a main seal ring groove having an axial length larger than the wire diameter of the main seal ring. The dust cut seal ring is disclosed to be arranged adjacent to the main seal ring groove and accommodated in a dust cut seal ring groove having an axial length substantially equal to the wire diameter of the dust cut seal ring.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] However, in conventional powder feeders, there is a risk of powder entering the screw drive unit area from the powder area side, and this problem cannot be solved by the invention described in Patent Document 1.

[0008] Furthermore, conventional powder feeders posed a risk of adverse effects on the product (powder) due to frictional heat generated between the screw and the bearing.

[0009] Furthermore, when using contact seals such as oil seals, dust seals, or O-rings for sealing, deterioration or wear of the seals may lead to, for example, foreign matter entering the powder area.

[0010] Therefore, non-contact gas sealing (also known as "air sealing") is extremely important.

[0011] The main objective of the present invention is to provide a non-contact mechanical seal that effectively addresses shaft runout and other issues, and is less prone to leakage of powders and other materials.

[0012] Another object of the present invention is to seal the drive unit area to prevent powder or other materials from leaking out.

[0013] Another objective of the present invention is to provide a non-contact seal. [Means for solving the problem]

[0014] A mechanical seal according to the first aspect of the present invention is a mechanical seal that can accommodate axial runout, axial elongation, or axial tilt of an axis including a stirring shaft or a screw shaft, The aforementioned mechanical seal comprises a seal body and The shaft insertion section into which the shaft is inserted, A valve portion that adjusts the clearance width between the seal body portion and the shaft insertion portion, A valve adjustment chamber moves the valve portion in a direction that narrows the clearance and adjusts the gas discharged from the clearance, It includes a retaining air chamber through which the gas discharged from the clearance passes, causing the valve portion to move in a direction that widens the clearance, and holding the shaft insertion portion, This mechanical seal increases the internal pressure around the shaft insertion portion within the retaining air chamber by the gas discharged into the retaining air chamber, and moves the valve portion by the pressure difference between the internal pressure of the retaining air chamber and the internal pressure of the valve adjustment air chamber, thereby adjusting the width of the clearance and adjusting the airflow rate of the gas discharged from the clearance.

[0015] With this design, it is possible to increase the internal pressure inside the seal body (air chamber) while suppressing the amount of gas discharged from the clearance.

[0016] Furthermore, because the shaft insertion part is held in place by gas, the shaft insertion part can be held in a non-contact state.

[0017] In other words, it can effectively address shaft runout, shaft elongation, or shaft inclination in shafts such as stirring shafts and screw shafts, and can provide a non-contact seal.

[0018] Note that "gas" includes air, but also other gases such as nitrogen and carbon dioxide.

[0019] A mechanical seal according to the second aspect of the present invention is a mechanical seal according to the first aspect, wherein by increasing the internal pressure of the valve regulating air chamber, the valve portion moves in a direction that narrows the clearance. The valve is a mechanical seal that moves in a direction that widens the clearance by increasing the internal pressure of the retaining air chamber.

[0020] When the internal pressure of the holding chamber is increased, the valve portion tends to move in a direction where the clearance becomes wider. However, by making the internal pressure of the valve adjustment chamber higher than the internal pressure of the holding chamber, the valve portion moves in a direction where the clearance becomes narrower, and the clearance can be narrowed.

[0021] The mechanical seal according to the third aspect of the present invention is the mechanical seal according to the first aspect, wherein by making the internal pressure of the valve adjustment chamber higher than the internal pressure of the holding chamber, the valve portion is moved, the clearance is narrowed, and the mechanical seal reduces the air volume of the gas discharged from the clearance.

[0022] By increasing the internal pressure of the holding chamber and narrowing the clearance, the air volume discharged from the clearance can be reduced.

[0023] The mechanical seal according to the fourth aspect of the present invention is a mechanical seal capable of accommodating shaft runout, shaft elongation, or shaft inclination of a shaft including a stirring shaft or a screw shaft, The mechanical seal includes a seal main body portion, a shaft insertion portion into which the shaft is inserted, a first valve portion that adjusts the width of a first clearance between the seal main body portion and the shaft insertion portion, a second valve portion that is disposed on the opposite side in the axial direction to the first valve portion and adjusts the width of a second clearance between the seal main body portion and the shaft insertion portion, a first valve adjustment chamber that moves the first valve portion in a direction where the first clearance becomes narrower and adjusts the gas discharged from the first clearance, a second valve adjustment chamber that moves the second valve portion in a direction where the second clearance becomes narrower and adjusts the gas discharged from the second clearance, a holding chamber through which the gas discharged from the first clearance and the second clearance passes, moves the first valve portion in a direction where the first clearance becomes wider, and moves the second valve portion in a direction where the second clearance becomes wider, and holds the shaft insertion portion. The gas discharged into the retaining air chamber increases the internal pressure around the shaft insertion portion within the retaining air chamber. The first valve is moved by the pressure difference between the internal pressure of the retaining air chamber and the internal pressure of the first valve adjustment air chamber. The second valve is moved by the pressure difference between the internal pressure of the retaining air chamber and the internal pressure of the second valve adjustment air chamber. This is a mechanical seal that adjusts the width of the first clearance and the second clearance, and adjusts the airflow rate of the gas discharged from the first clearance and the second clearance.

[0024] Even with this configuration, it produces the same effect as in the first phase.

[0025] A mechanical seal according to a fifth aspect of the present invention is a mechanical seal capable of accommodating axial runout, axial elongation, or axial inclination of an axis including a stirring shaft or a screw shaft, The aforementioned mechanical seal comprises a seal body and The shaft insertion section into which the shaft is inserted, A valve portion that adjusts the clearance width between the seal body portion and the shaft insertion portion, A fixing part for fixing the position of the valve part, An adjustment unit for adjusting the fixing position of the valve portion, It includes a retaining air chamber through which the gas discharged from the clearance passes and which holds the shaft insertion portion, This mechanical seal increases the internal pressure around the shaft insertion portion within the retaining air chamber by releasing gas into the retaining air chamber.

[0026] In this configuration, the valve itself does not move, but its position can be adjusted, and the clearance width can be adjusted.

[0027] Furthermore, because the shaft insertion part is held in place by gas, the shaft insertion part can be held in a non-contact state. [Brief explanation of the drawing]

[0028] [Figure 1]An exploded perspective view of a mechanical seal according to one embodiment of the present invention. [Figure 2] A cross-sectional perspective view of a mechanical seal according to the same embodiment. [Figure 3] A partial cross-sectional view of a mechanical seal according to the same embodiment. [Figure 4] A partial cross-sectional view of a mechanical seal according to the same embodiment. [Figure 5] A partial cross-sectional view of a mechanical seal according to one embodiment of the present invention. [Figure 6] A cross-sectional view of section AA of a mechanical seal according to one embodiment of the present invention. [Figure 7] A partial cross-sectional view of a mechanical seal according to one embodiment of the present invention. [Figure 8] A partial cross-sectional view of a mechanical seal according to the same embodiment. [Figure 9] A partial cross-sectional view of a mechanical seal according to one embodiment of the present invention. [Figure 10] An exploded perspective view of the mechanical seal according to the same embodiment. [Figure 11] A partial cross-sectional view of a powder bagging machine using a mechanical seal according to one embodiment of the present invention. [Modes for carrying out the invention]

[0029] The first mechanical seal 100 according to this embodiment will be described with reference to the drawings.

[0030] The first mechanical seal 100 is attached to the screw shaft 11 and seals to prevent powder or other materials from entering the drive mechanism.

[0031] <First Embodiment> As shown in Figures 1 to 4, the first mechanical seal 100, which is a mechanical seal, comprises the first seal body portion 110, which is the seal body portion, The first shaft insertion section 120 is a shaft insertion section into which the screw shaft 11 is inserted, A first valve portion 130 is a valve portion that adjusts the width of the first clearance C between the first seal body portion 110 and the first shaft insertion portion 120, A first gas supply unit 140 is a gas supply unit for moving the first valve unit 130 and adjusting the gas discharged from the first clearance C, which is the clearance, The first valve control chamber 150 is a passage for the gas discharged from the first gas supply unit 140 and is a valve control chamber for increasing the internal pressure to move the first valve unit 130, A second gas supply unit 160 is a gas supply unit that supplies gas discharged from the first clearance C, The first retaining air chamber 170 is a passage for the gas discharged from the second gas supply section 160 and is a retaining air chamber that holds the first shaft insertion section 120, A cover portion 180 located on the drive unit area side, It includes a first safety part 190, which is a safety part that prevents the first valve part 130 from coming into contact with the tip of the first shaft insertion part 120.

[0032] The first seal body 110 is attached and fixed to the screw shaft 11 of the screw (in this embodiment, an auger screw is used), but it may also be attached to the stirring shaft of the stirring blade, and the mounting shaft is not particularly limited.

[0033] The first seal body portion 110 has a first groove portion 111 which is a groove portion for inserting the first valve portion 130, A through hole 112 for inserting the first shaft insertion part 120 is provided in the central part.

[0034] Furthermore, the first seal body portion 110 is provided with a first valve regulating air chamber 150 and a first retaining air chamber 170, which are passages for gas.

[0035] As shown in Figure 1, the first groove 111 has a width (radial width) that allows the annular first valve portion 130 to be inserted, and a depth that allows the valve portion to slide back and forth (sliding in the x-axis direction).

[0036] The first shaft insertion section 120 is where the screw shaft 11 is inserted.

[0037] As shown in Figures 1 and 2, the first shaft insertion portion 120 has an annular cylindrical shape in yz plane view, and its inner diameter is slightly larger than the outer diameter of the screw shaft 11, allowing the screw shaft 11 to be inserted.

[0038] Furthermore, the outer diameter of the first tip portion 121, which is the tip end (positive x-axis direction side) of the first shaft insertion portion 120, is larger than that of the base end (negative x-axis direction side), and is sloped so that the thickness decreases as it moves radially outward.

[0039] The first clearance C is formed by the first valve portion 130 and the first tip portion 121 of the first shaft insertion portion 120.

[0040] The through-hole 112 is a circular through-hole located in the center of the yz plane view, into which the first shaft insertion portion 120 is inserted.

[0041] In this embodiment, the through hole 112 constitutes the first retaining air chamber 170.

[0042] The first valve section 130 adjusts the width of the first clearance C. The movement of the first valve section 130 within the first groove 111 is performed by the difference between the internal pressure in the first valve adjustment chamber 150 and the internal pressure in the first retaining chamber 170.

[0043] In this embodiment, the first valve section 130 is composed of a first valve member 131, an inner O-ring 132, and an outer O-ring 133.

[0044] The first valve member 131 is annular in yz-plane view and slides in the x-axis direction.

[0045] The first valve member 131 has a first protrusion 131a on the radially outward side in a yz-plane view, and the first protrusion 131a contacts the first safety portion 190, thereby preventing the first valve member 131 from contacting the first tip portion 121 of the first shaft insertion portion 120.

[0046] As shown in Figure 5, the first valve portion 130 may have only one O-ring (O-ring 134).

[0047] As the first valve portion 130 moves to the right (towards the positive x-axis direction), the first clearance C narrows.

[0048] Furthermore, the first clearance C widens as the first valve portion 130 moves to the left (negative x-axis direction).

[0049] The first gas supply unit 140 discharges gas into the first valve control chamber 150 and pushes the first valve unit 130 with the pressure of the gas (internal pressure in the first valve control chamber 150) in the direction that narrows the first clearance C (positive x-axis direction).

[0050] The first valve control chamber 150 is through which the gas discharged from the first gas supply unit 140 passes.

[0051] The first retaining gas chamber 170 is through which the gas discharged from the second gas supply unit 160 passes.

[0052] The first retaining air chamber 170 is a space consisting of a first passage 514 connected to the through hole 112, the outer periphery of the through hole 112 and the first shaft insertion portion 120, and the cover portion 180 (first sealing member 182).

[0053] The first retaining air chamber 170 has a structural portion S that is perpendicular to the shaft insertion portion 120, and the gas discharged into the first retaining air chamber 170 flows perpendicular to the shaft insertion portion 120 from the radially outer side in the yz plane.

[0054] The second gas supply unit 160 discharges gas into the first retaining gas chamber 170 and pushes the first valve unit 130 with the pressure of the gas in the direction in which the first clearance C opens (negative x-axis direction).

[0055] The gas discharged from the second gas supply unit 160 is discharged after passing through the first clearance C (in this embodiment, it is discharged towards the powder area).

[0056] Gas is discharged from the first clearance C to the powder area side of the powder filling section 300, preventing the powder from flowing into the drive section area side of the powder filling section 300.

[0057] Furthermore, the internal pressure in the first retaining chamber 170 increases due to the gas, preventing foreign matter such as powder from entering the first retaining chamber 170 side (drive unit area side) due to the pressure difference.

[0058] Furthermore, for example, by increasing the internal pressure of the first retaining air chamber 170, the pressure difference can prevent powder from mixing from the powder area side to the drive unit area side.

[0059] Furthermore, since the first shaft insertion portion 120 and the first seal body portion 110 are separated by gas and are in a non-contact state, damage to the seal mechanism can be prevented even if shaft runout, shaft elongation, or shaft tilt occurs.

[0060] However, if the internal pressure of the first retaining air chamber 170 is increased, the airflow rate of the gas discharged from the first clearance C will also increase.

[0061] If the airflow rate or velocity of the gas discharged from the first clearance C increases, it may affect the flow of materials such as powders.

[0062] On the other hand, if the airflow rate or velocity of the gas discharged from the first clearance C is reduced, the internal pressure of the first retaining air chamber 170 will decrease, which could lead to powder mixing from the powder area to the drive unit area.

[0063] Furthermore, there is a risk that the powder, affected by frictional heat, may flow back into the powder area.

[0064] However, with the mechanical seal 100 of this embodiment, the width of the first clearance C can be adjusted by the first valve portion 130, and the airflow rate of the gas discharged from the first clearance C can be adjusted.

[0065] The lid portion 180 is positioned on the drive unit area side (negative x-axis direction side) to prevent gas in the first retaining air chamber 170 from leaking to the drive unit area side.

[0066] The lid portion 180 consists of a first lid member 181, which is a lid member, A first sealing member 182 is a sealing member that is positioned on the inner diameter side of the first lid member 181, A first lid O-ring 183 is positioned between the first lid member 181 and the first seal body portion 110, It consists of a lid holding portion 184 that holds the first sealing member 182.

[0067] The first cover member 181 is annular in yz plane view, fixes the first sealing member 182, and prevents gas leakage to the drive unit area side.

[0068] The first sealing member 182 is annular in yz plane view and seals the periphery of the first shaft insertion portion 120.

[0069] As can be seen from Figures 3 to 5, the first sealing member 182 has a "V-shaped" cross-section.

[0070] Therefore, as the internal pressure in the first retaining air chamber 170 increases, a force in the direction of the arrow is applied to the first sealing member 182 (a force is applied in the direction that opens the "L" shape), and the force holding the first shaft insertion portion 120 increases.

[0071] The first sealing member 182 may have its positive x-axis direction and negative x-axis direction reversed.

[0072] In this case, the higher the internal pressure in the first retaining air chamber 170, the greater the force applied in the direction that closes the "L" shape, and the less force is applied to hold the first shaft insertion portion 120.

[0073] The first sealing member 182 is slidably mounted to the first shaft insertion portion 120.

[0074] The first sealing member 182 is attached to and fixed to the first lid member 181.

[0075] The first lid O-ring 183 is positioned between the first lid member 181 and the first seal body 110 to prevent gas leakage from the gap between the first lid member 181 and the first seal body 110.

[0076] The first safety section 190 is designed to prevent the first valve section 130 and the first shaft insertion section 120 from coming into contact.

[0077] For example, if the internal pressure in the first valve adjustment chamber 150 becomes significantly higher than the internal pressure in the first retaining chamber 170, and the first valve portion 130 moves too far in a direction that narrows the first clearance C, the first valve portion 130 may come into contact with the first shaft insertion portion 120.

[0078] If the first valve portion 130 moves too far in the direction that narrows the first clearance C, the first safety portion 190 contacts the first valve portion 130 to prevent it from moving in the direction that narrows the clearance C.

[0079] Specifically, the first protrusion 131a of the first valve portion 130 comes into contact with the first safety portion 190, thereby preventing contact between the first valve portion 130 and the first tip portion 121 of the first shaft insertion portion 120.

[0080] In this embodiment, the first safety unit 190 is positioned radially outward in the yz plane with respect to the x-axis of the first valve unit 130, and is located on the positive x-axis side.

[0081] The first safety section 190 has a ring shape in yz plane view and is positioned between the first valve section 130 and the first tip section 121 of the first shaft insertion section 120.

[0082] Tables 1, 2, and 3 below show an example of measuring the internal pressure in the first retaining chamber 170 when the airflow is reduced and the valve pressure (the internal pressure in the first valve adjustment chamber 150 that pushes the first valve section 130 in the direction of closing the first clearance C) is increased.

[0083] As shown in Figure 6, the internal pressure of the first valve control chamber 150 is measured by pressure gauge P1, and the internal pressure of the first retaining chamber 170 is measured by pressure gauge P2.

[0084] Furthermore, as shown in Figures 2 to 5, the airflow rate to the first valve control chamber 150 is measured by flow meter F1, and the airflow rate to the first holding chamber 170 is measured by flow meter F2.

[0085] [Table 1]

[0086] Table 1 shows the internal pressure when the valve pressure is adjusted to reduce the airflow from 30 L / min.

[0087] As can be seen from Table 1, even if the airflow is reduced, the internal pressure can be increased by increasing the valve pressure.

[0088] [Table 2]

[0089] Table 2 shows the internal pressure when the valve pressure is adjusted to reduce the airflow from 40 L / min.

[0090] [Table 3]

[0091] Table 3 shows the internal pressure when the valve pressure is adjusted to reduce the airflow from 50 L / min.

[0092] As can be seen from Tables 2 and 3, similar to Table 1, the internal pressure can be increased by increasing the valve pressure even when the airflow is reduced.

[0093] As shown in Figure 11, in this embodiment, the first valve portion 130 is used only on the powder area side, but it may also be provided on the opposite side (negative x-axis direction side) on the drive unit area side, or it may be used on both sides (powder area side and drive unit area side).

[0094] By increasing the airflow, powder adhesion can be blown away, and by increasing the internal pressure, powder can be prevented from entering the drive unit area.

[0095] <Second Embodiment> In the first embodiment, the first valve portion 130 was configured to be on only one side, but in the second embodiment, the valve portions are arranged on both sides.

[0096] Specifically, as shown in Figure 7, the valve section (first valve section 130, second valve section 230) is provided on both the left and right sides (positive x-axis side, negative x-axis side). Explanations of configurations similar to the first embodiment will be omitted or simplified.

[0097] In the second embodiment, the second mechanical seal 200, which is a mechanical seal, comprises a second seal body portion 210, The second shaft insertion section 220 is a shaft insertion section into which the screw shaft 11 is inserted, A first valve portion 130 is a valve portion located on the positive x-axis side that adjusts the width of the first clearance C between the first seal body portion 110 and the second shaft insertion portion 220, A first gas supply unit 140 is a gas supply unit for moving the first valve unit 130 and adjusting the gas discharged from the first clearance C, The first valve control chamber 150 is a passage for the gas discharged from the first gas supply unit 140, and is used to increase the internal pressure and move the first valve unit 130. A second gas supply unit 160 is a gas supply unit that discharges the gas discharged from the first clearance C, This is a passage for the gas discharged from the second gas supply section 160, and includes a first holding gas chamber 170 that holds the second shaft insertion section 220, A first safety part 190 is a safety part positioned on the positive x-axis side to prevent the first valve part 130 from coming into contact with the second shaft insertion part 220, A second valve portion 230 is a valve portion located on the negative x-axis side that adjusts the width of the second clearance D, which is the clearance between the first seal body portion 110 and the second shaft insertion portion 220, A third gas supply unit 240 is a gas supply unit for moving the second valve unit 230 and adjusting the gas discharged from the second clearance D, This is a passage for the gas discharged from the third gas supply unit 240, and includes a second valve regulating air chamber 250 for increasing the internal pressure to move the second valve unit 230, A fourth gas supply unit 260 is a gas supply unit that discharges the gas discharged from the second clearance D, This is a passage for the gas discharged from the fourth gas supply section 260, and includes a second holding gas chamber 270 that holds the second shaft insertion section 220, The device includes a second safety section 290, which is a safety section positioned on the negative x-axis side to prevent the second valve section 230 from coming into contact with the second shaft insertion section 220.

[0098] The second seal body 210 is configured to have valve sections (first valve section 130 and second valve section 230) at both ends, and a structure for this purpose is provided. The specific configuration is the same as that of the first seal body 110, and the configuration of the left side (negative x-axis direction side) of the second seal body 210 is the same as the configuration of the right side (positive x-axis direction side) of the first seal body 110.

[0099] The configuration of the second axis insertion section 220 on the left side (positive x-axis direction side) is the same as that of the first axis insertion section 120.

[0100] The configuration of the right side (negative x-axis direction side) of the second axis insertion section 220 differs from that of the first axis insertion section 120, and is the same as the configuration of the left side (positive x-axis direction side).

[0101] In other words, the second shaft insertion section 220 has an annular cylindrical shape when viewed in the yz plane, and its inner diameter is slightly larger than the outer diameter of the screw shaft 11, allowing the screw shaft 11 to be inserted.

[0102] Furthermore, the outer diameter of the first tip portion 121, which is the tip end on the front end side (positive x-axis direction side) of the second shaft insertion portion 220, and the second tip portion 221, which is the tip end on the base end side (negative x-axis direction side), are larger than the central portion (central portion in the x-axis direction), and are inclined so that the thickness decreases as it moves radially outward.

[0103] The second valve section 230 has the same configuration as the first valve section 130, and the second clearance D is narrowed when the second valve section 230 moves to the left (negative x-axis direction).

[0104] Furthermore, the second clearance D widens as the second valve portion 230 moves to the right (towards the positive x-axis direction).

[0105] In other words, the second valve member 231 has a second protrusion 231a on the radially outward side in a yz-plane view, and the second protrusion 231a contacts the second safety portion 290, thereby preventing the second valve member 231 from contacting the second tip portion 221 of the second shaft insertion portion 220.

[0106] The third gas supply unit 240 has the same configuration as the first gas supply unit 140, and the third gas supply unit 240 discharges gas into the second valve control chamber 250 and pushes the second valve unit 230 with the pressure of the gas (internal pressure in the second valve control chamber 250) in the direction that narrows the second clearance D (negative x-axis direction).

[0107] The third gas supply unit 240 may be the same as the first gas supply unit 140.

[0108] The second valve-regulating chamber 250 has the same configuration as the first valve-regulating chamber 150, so its explanation is omitted.

[0109] The fourth gas supply unit 260 has the same configuration as the second gas supply unit 160, so its description is omitted. Note that the fourth gas supply unit 260 may be identical to the second gas supply unit 160.

[0110] The second retaining air chamber 270 has the same configuration as the first retaining air chamber 170, so its description is omitted.

[0111] The second safety unit 290 has the same configuration as the first safety unit 190, so its explanation will be omitted.

[0112] <Third Embodiment> In the first and second embodiments, the first valve section 130 (or the second valve section 230) was moved by the pressure of the gas, but in the third embodiment, the first valve section 130 (or the second valve section 230) is fixed in place.

[0113] In the third embodiment, the same configuration as in the first embodiment will be omitted or simplified in the description. Furthermore, the contents of the third embodiment may also be used in the second embodiment.

[0114] As shown in Figures 9 and 10, the third mechanical seal 300, which is a mechanical seal, comprises the third seal body portion 310, The first shaft insertion section 120 is a shaft insertion section into which the screw shaft 11 is inserted, A third valve section 330 is a valve section that adjusts the width of the third clearance E, which is the clearance between the third seal body section 310 and the first shaft insertion section 120, A fixing part 340 for fixing the position of the third valve part 330, An adjustment unit 350 adjusts the fixed position of the third valve unit 330 and adjusts the width of the third clearance E, The second gas supply unit 160 is a gas supply unit that supplies gas discharged from the third clearance E, The first retaining air chamber 170 is a passage for the gas discharged from the second gas supply section 160 and is a retaining air chamber that holds the first shaft insertion section 120, It includes a cover portion 180 located on the drive unit area side.

[0115] The third seal body portion 310 has a third groove portion 311 which is a groove portion for inserting the third valve portion 330, The central part has a through hole 312 into which the first shaft insertion part 120 is inserted, A valve through-hole 313 is provided for inserting a fixing part 340 for fixing the third valve part 330.

[0116] The third groove 311 and the valve through hole 313 are connected, and the third valve portion 330 is fixed by the fixing portion 340 into which the valve through hole 313 is inserted.

[0117] In this embodiment, four valve through-holes 313 are provided in the third seal body 310 and are arranged at equal intervals on the same circumference in the yz plane.

[0118] The third valve section 330 consists of a third valve member 331, an inner O-ring 332, and an outer O-ring 333.

[0119] The third valve member 331 is into which the fixing portion 340 can be inserted and has a hole 331b for inserting the fixing portion 340.

[0120] The fixing portion 340 secures the third valve portion 330. In this embodiment, the fixing portion 340 is a bolt, which is inserted into the valve portion through hole 313 from the negative x-axis direction to secure the third valve portion 330 to the third seal body portion 310.

[0121] The adjustment unit 350 is positioned between the fixed unit 340 and the third valve unit 330, and adjusts the position of the third valve unit 330 in the third groove unit 311.

[0122] In other words, the adjustment unit 350 indirectly adjusts the width of the third clearance E.

[0123] In this embodiment, the adjustment section 350 is a shim, and although five shims are stacked in Figure 10, the number is not limited. The position of the third valve section 330 in the third groove section 311 is adjusted by the number of shims.

[0124] Furthermore, the second and third embodiments may be combined. For example, the first valve portion 130 and the second valve portion 230 of the second embodiment may be fixed in a configuration similar to a third valve portion, or at least one of the first valve portion 130 and the second valve portion 230 may be made into the third valve portion 330.

[0125] Figure 11 is a partial cross-sectional view of a powder filling machine using the first mechanical seal 100 according to this embodiment.

[0126] By using the first mechanical seal 100, it is possible to effectively prevent powder from entering the drive unit side, and because it is a non-contact state, damage to the shaft can be prevented even if shaft runout, shaft elongation, or shaft tilt occurs.

[0127] The present invention can also be implemented in various improved, modified, or altered forms without departing from its spirit. [Explanation of Symbols]

[0128] 100 First Mechanical Seal (Mechanical Seal) 110 First seal body (seal body) 120 First shaft insertion section (shaft insertion section) 130 First Department (Department) 140 First Gas Supply Unit (Gas Supply Unit) 150 First valve-regulated chamber (valve-regulated chamber) 160 Second Gas Supply Unit (Gas Supply Unit) 170 First retaining chamber (retaining chamber) 180 Lid 190 1st Safety Department (Safety Department) 200 Second Mechanical Seal (Mechanical Seal) 210 Second seal body (seal body) 220 Second shaft insertion section (shaft insertion section) 230 Second valve section (valve section) 250 Second valve regulating chamber 270 Second retaining chamber 290 2nd Safety Department (Safety Department) 300 Third Mechanical Seal (Mechanical Seal) 310 Third seal body (seal body) 340 Fixed part 350 Adjustment section

Claims

1. A mechanical seal capable of accommodating shaft runout, shaft elongation, or shaft inclination of shafts including stirring shafts and screw shafts, The aforementioned mechanical seal comprises a seal body and The shaft insertion section into which the shaft is inserted, A valve portion that adjusts the clearance width between the seal body portion and the shaft insertion portion, A valve adjustment chamber moves the valve portion in a direction that narrows the clearance and adjusts the gas discharged from the clearance, It includes a retaining air chamber through which the gas discharged from the clearance passes, causing the valve portion to move in a direction that widens the clearance, and holding the shaft insertion portion, A mechanical seal that increases the internal pressure around the shaft insertion portion within the retaining air chamber by the gas discharged into the retaining air chamber, moves the valve portion by the pressure difference between the internal pressure of the retaining air chamber and the internal pressure of the valve adjustment air chamber, adjusts the width of the clearance, and adjusts the airflow rate of the gas discharged from the clearance.

2. By increasing the internal pressure of the valve control chamber, the valve portion moves in a direction that narrows the clearance. The mechanical seal according to claim 1, wherein the valve portion moves in a direction that widens the clearance by increasing the internal pressure of the retaining air chamber.

3. The mechanical seal according to claim 1, wherein the internal pressure of the valve adjustment chamber is made higher than the internal pressure of the retaining chamber, thereby moving the valve portion, narrowing the clearance, and reducing the airflow rate of gas discharged from the clearance.

4. A mechanical seal capable of accommodating shaft runout, shaft elongation, or shaft inclination of shafts including stirring shafts and screw shafts, The aforementioned mechanical seal comprises a seal body and The shaft insertion section into which the shaft is inserted, A first valve portion that adjusts the width of the first clearance between the seal body portion and the shaft insertion portion, A second valve portion is positioned on the axial opposite side from the first valve portion and adjusts the width of the second clearance between the seal body portion and the shaft insertion portion, A first valve adjustment chamber moves the first valve portion in a direction that narrows the first clearance, thereby adjusting the gas discharged from the first clearance, A second valve adjustment chamber moves the second valve portion in a direction that narrows the second clearance, thereby adjusting the gas discharged from the second clearance, The device includes a retaining air chamber through which the gas discharged from the first clearance and the second clearance passes, causing the first valve portion to move in a direction that widens the first clearance, and the second valve portion to move in a direction that widens the second clearance, and which holds the shaft insertion portion. The gas discharged into the retaining air chamber increases the internal pressure around the shaft insertion portion within the retaining air chamber. The first valve is moved by the pressure difference between the internal pressure of the retaining air chamber and the internal pressure of the first valve adjustment air chamber. The second valve is moved by the pressure difference between the internal pressure of the retaining air chamber and the internal pressure of the second valve adjustment air chamber. A mechanical seal that adjusts the width of the first clearance and the second clearance, and adjusts the airflow rate of the gas discharged from the first clearance and the second clearance.

5. A mechanical seal capable of accommodating shaft runout, shaft elongation, or shaft inclination of shafts including stirring shafts and screw shafts, The aforementioned mechanical seal comprises a seal body and The shaft insertion section into which the shaft is inserted, A valve portion that adjusts the clearance width between the seal body portion and the shaft insertion portion, A fixing part for fixing the position of the valve part, An adjustment unit for adjusting the fixing position of the valve portion, It includes a retaining air chamber through which the gas discharged from the clearance passes and which holds the shaft insertion portion, A mechanical seal that increases the internal pressure around the shaft insertion portion within the retaining air chamber by releasing gas into the retaining air chamber.

Images