JP2009209976A - Silencer and pressure control device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly versatile silencer for reducing a sound generated in a pipe for flowing fluid, when the type or use state of the pressure control device is different, and the pressure control device including the silencer and controlling pressure of the fluid in the pipe. <P>SOLUTION: This silencer 10 comprises a plate-like part 50. The plate-like part 50 is arranged on the downstream side in a flow of the fluid more than a passing hole opened-closed by displacement of a piston 14 in the pipe for flowing the fluid. The plate-like part 50 is also arranged by partitioning an upstream side space and a downstream side space, and a plurality of through-holes 55 are formed. The through-holes 55 are formed to be blocked up, and can communicate the upstream space with the downstream space. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a silencer that reduces noise generated in a pipeline through which fluid flows, and a pressure control device that includes the silencer and controls the pressure of fluid in the pipeline.

  FIG. 10 is a cross-sectional view of a high pressure governor 2 including a silencer 1 according to the prior art. There has never been a silencer whose characteristics can be changed according to the type or usage of the pressure control device, and a high pressure governor 2 in which the silencer 1 is located outside the body 3 is known as a pressure control device with a silencer. It is done. (For example, refer to Patent Document 1).

JP 2006-194157 A

  The silencer of the high pressure governor 1 also has a problem that the characteristics of the silencer are not variable, and if the type or usage of the pressure control device changes, the characteristics of the silencer cannot be changed accordingly.

  An object of the present invention is to provide a highly versatile silencer that reduces the sound generated in a pipeline through which a fluid flows when the type or usage of the pressure control device is different, and the pressure of the fluid in the pipeline including the silencer. It is to provide a pressure control device to control.

  According to the present invention, the silencer includes a plate-like portion. The plate-like portion is provided on the downstream side of the fluid flow with respect to the passage hole that is opened and closed by the displacement of the piston in the conduit through which the fluid flows. The plate-like portion is provided by partitioning the upstream space and the downstream space, and a plurality of through holes are formed. The through hole is formed so as to be able to be closed, and can communicate the upstream space and the downstream space.

  According to the present invention, when the fluid upstream of the plate-like portion moves downstream through the through hole formed in the plate-like portion, the pressure in the space upstream of the plate-like portion. And a pressure in the downstream space can cause a pressure difference. Since the plurality of through holes are formed so as to be occluded, the ratio of the through holes that connect the upstream space and the downstream space among all the through holes can be changed by closing the through holes. Therefore, the pressure difference between the pressure in the space upstream of the plate-like portion and the pressure on the downstream side can be changed.

  Thereby, the pressure difference between the pressure of the fluid upstream of the passage hole and the pressure of the fluid downstream of the passage hole and upstream of the plate-like portion is compared with the case where no plate-like portion is provided. Can be small. Therefore, the volume expansion coefficient when the fluid upstream of the passage hole moves downstream of the passage hole can be reduced as compared with the case where the plate-like portion is not provided. By reducing the pressure difference, the fluid flow disturbance can be reduced, and the fluid velocity can be prevented from becoming sonic. Therefore, the sound generated when the fluid upstream of the passage hole moves downstream of the passage hole can be reduced.

  Since the through-hole is formed so as to be openable and closable, the sound generated in the conduit through which the fluid flows can be reduced by adjusting the amount of opening and closing when the type or usage of the pressure control device is different. Therefore, a highly versatile silencer can be realized. Since the pressure control device includes the silencer, it is possible to efficiently reduce the sound generated when the fluid upstream of the passage hole moves downstream of the passage hole.

  Hereinafter, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings. In the following description, parts corresponding to matters already described in the forms preceding each form may be denoted by the same reference numerals, and overlapping descriptions may be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in the preceding section. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder. The following description includes a description of the silencer 10 and the pressure control device 11 including the silencer 10.

  FIG. 1 is a cross-sectional view of a pressure control device 11 according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the pressure control device 11 according to the first embodiment of the present invention, taken along the line AA in FIG. The pressure control device 11 according to the first embodiment includes a silencer 10 that reduces sound generated in a pipeline through which fluid flows, and controls the pressure of the fluid in the pipeline. The pressure control device 11 according to the first embodiment further includes a cylinder 12, a piston rod 13, a piston 14, an O-ring 16, a pipe line structure 17, a drive unit 19, and a control unit 21. Is done.

  The cylinder 12 includes a cylinder disc 22 and a cylinder cylindrical portion 24. The cylinder disk 22 is a plate-like portion 50 whose outer shape is formed in a circular shape, and the piston rod 13 is inserted into the plate-like portion 50 so as to be displaceable in the axial direction thereof.

  One end of the cylinder cylindrical portion 24 in the sliding direction Z1 is connected to the cylinder disk 22. The cylinder cylindrical portion 24 is formed integrally with the cylinder disc 22. A plurality of through holes 25 penetrating in the radial direction are formed on the side surface of the cylinder cylindrical portion 24. In the first embodiment, the transmission hole 25 is the passage hole. The plurality of transmission holes 25 are also formed in the circumferential direction around the sliding axis of the cylinder cylindrical portion 24 and are also formed in the sliding direction Z of the cylinder cylindrical portion 24. A portion that defines the transmission hole 25 is referred to as a “transmission hole defining portion”. The plurality of transmission holes 25 formed in the cylinder cylindrical portion 24 are formed along a spiral line. The spiral line is a line that spirally rotates around the sliding axis in the circumferential direction of the cylinder cylindrical portion 24 as it goes in the sliding direction one Z1. At least part of the positions in the sliding direction Z of the adjacent transmission holes 25 on the spiral line overlaps with the sliding direction Z. By forming the plurality of transmission holes 25 in this way, when the piston 14 is displaced in the sliding direction Z, the amount of fluid passing through the cylinder cylindrical portion 24 is continuously increased with the displacement of the piston 14. Can be changed.

  The piston 14 is fitted to the cylinder cylindrical portion 24 and is installed inward of the cylinder cylindrical portion 24 in the radial direction. The piston 14 is positioned in the other sliding direction Z2 than the piston rod 13, and the end of the other sliding direction Z2 of the piston rod 13 is connected to the end of the sliding direction one Z1 of the piston 14. The piston 14 is displaced in the sliding direction Z with respect to the cylinder 12 together with the piston rod 13.

  An O-ring 16 is fitted to the outer peripheral surface of the piston 14 radially outward from the sliding axis. The O-ring 16 is made of, for example, resin, and is tightly fitted to the cylinder cylindrical portion 24 from the inside in the radial direction of the cylinder cylindrical portion 24. The dimension of the O-ring 16 in the radial direction is uniform in the circumferential direction around the sliding axis.

  The pipe line structure 17 includes an upstream flange 26, a downstream flange 27, and a partition wall 28, and is integrally formed. The pipe line structure 17 is a member that constitutes a region where the fluid flows, and the fluid is, for example, city gas. The upstream end of the pipe line structure 17 is adjacent to the upstream side of the pipe line structure 17 and is connected to an upstream pipe 31 (shown in FIG. 6) connected to the pipe line structure 17. The downstream end of the pipe line structure 17 is adjacent to the downstream side of the pipe line structure 17 and is connected to a downstream pipe 32 connected to the pipe line structure 17.

  The flow direction of the fluid flowing through the pipe line defined at the upstream end of the pipe structure 17 and the flow direction of the fluid flowing through the pipe line defined at the downstream end coincide with each other. The flow direction of the fluid flowing in the pipe line defined by the upstream end and the downstream end is “flow path direction X”, and among the flow path directions X, the direction toward the upstream is “flow path direction one X1”. And

  The partition wall 28 is installed at a midway position between the upstream side and the downstream side with respect to the flow direction of the fluid flowing through the internal space of the pipe structure 17, and is provided on the pipe structure 17 that partitions the upstream side and the downstream side. It is a part. Of the internal space partitioned by the partition wall 28, the fluid located on the upstream side is referred to as “primary fluid”, and the fluid located on the downstream side is referred to as “secondary fluid”. In the first embodiment, the pressure of the fluid in the upstream pipe 31 is “primary pressure”, and the pressure of the fluid in the downstream pipe 32 is “secondary pressure”. The pressure control device 11 according to the present embodiment performs pressure control in order to keep the secondary pressure at a target pressure. The pressure determined as the target as the secondary pressure is referred to as “target secondary pressure”.

  An opening 33 is formed in a part of the partition wall 28. The opening 33 penetrates the partition wall 28 in the sliding direction Z and communicates the upstream space 36 where the primary fluid is located and the space downstream of the partition wall 28 where the secondary fluid is located. Of the space defined by the pipe structure 17, the space upstream of the partition wall 28 where the primary fluid is located is referred to as “upstream space”. A portion of the partition wall 28 that defines the opening 33 is referred to as an “opening”. The opening 34 is a substantially circular plate-like portion 50 when viewed in the sliding direction Z, and the thickness direction of the opening 34 coincides with the sliding direction Z. When the opening 33 is viewed in the sliding direction Z, it is circular, and the center of the opening 33 viewed in the sliding direction Z coincides with the sliding axis. In order to prevent the opening 34 from becoming a significant resistance to the flow of the fluid even when the flow rate of the fluid flowing through the pipe line structure 17 is the maximum within a predetermined range, The inner diameter is set sufficiently large.

  The other end in the sliding direction Z2 of the cylinder cylindrical portion 24 is disposed in contact with the partition wall 28 over the entire circumference around the sliding axis. A sealing portion 28a made of synthetic rubber or synthetic resin is formed over the entire circumference in a portion corresponding to the protruding portion 14a of the piston 14 in the surface portion of the one side Z1 in the sliding direction of the partition wall 28. When the piston 14 is displaced most in the other sliding direction Z2, the projecting portion 14a of the piston 14 abuts on the sealing portion 28a. As a result, the opening 33 is closed and fluid movement is prevented.

  The drive unit 19 may be configured to be controlled by a diaphragm that is operated by the atmospheric pressure, the secondary pressure, and the elastic restoring force of the spring, and may be driven by a differential pressure between the atmospheric pressure and the secondary pressure. Then, a connection member, a ball screw, an electric motor, a coupling (all not shown), etc. are comprised. The drive unit 19 may be a pilot type governor that is operated by adjusting a driving pressure with a pilot governor, for example.

  Since the piston 14 is connected to the piston rod 13, the piston 14 is displaced in the sliding direction Z as the piston rod 13 is displaced. As a result, the O-ring 16 provided on the outer periphery of the piston 14 slides in the sliding direction Z with respect to the cylinder cylindrical portion 24.

  A space located on the other side in the sliding direction Z2 from the piston 14 and radially inward with respect to the sliding axis from the cylinder cylindrical portion 24 is referred to as a “piston space”. In the piston space 49, the fluid is prevented from moving in one sliding direction Z1 by the end surface of the other sliding direction Z2 of the piston 14. Since the opening 33 of the partition wall 28 is formed to be sufficiently large and the opening 34 is prevented from resisting the flow of fluid, the pressure of the fluid in the piston space 49 is the primary pressure. When the piston 14 is displaced from the state in contact with the sealing portion 28a to one side Z1 in the sliding direction and the space defined by the transmission hole 25 formed in the cylinder cylindrical portion 24 is continuous with the piston space 49, the fluid in the piston space 49 Moves along the fluid flow and passes through the perforation hole 25 radially outward with respect to the sliding axis.

  The permeation hole defining portion exposed in the piston space 49 and the portion of the piston 14 in contact with the permeation hole defining portion act as a resistance against the flow of fluid, and therefore the cylinder cylindrical portion 24 with respect to the sliding axis from the piston space 49. The pressure of the fluid moved radially outward is lower than the primary pressure. The silencer 10 is provided outside the cylinder cylindrical portion 24 in the radial direction and away from the cylinder cylindrical portion 24 in the radial direction.

  FIG. 3 is a perspective view of the plate-like portion 50 in the first embodiment of the present invention. FIG. 4 is a cross-sectional view of the plate-like portion 50 according to the first embodiment of the present invention, cut along a plane including the sliding axis. The silencer 10 includes a plate-like portion 50 and a plurality of closing portions 51. The plate-like portion 50 is provided on the downstream side of the fluid flow with respect to the passage hole opened and closed by the displacement of the piston 14 in the conduit through which the fluid flows. In the present embodiment, the passage hole is a transmission hole 25 formed in the cylinder cylindrical portion 24. The plate-like portion 50 is provided by partitioning a space on the upstream side and a space on the downstream side of the plate-like portion 50. The plate-like portion 50 is formed in a cylindrical shape having an axis in the displacement direction of the piston 14 and surrounds the cylinder 12 into which the piston 14 is fitted.

  The plate-like portion 50 is a cylindrical member that is disposed radially outwardly from the cylinder cylindrical portion 24 with respect to the sliding axis and spaced apart in the radial direction. The plate-like portion 50 is a plate-like member formed by being curved around the sliding axis, and the cylindrical axis of the plate-like portion 50 coincides with the sliding axis. Therefore, the thickness direction of the plate-like portion 50 coincides with the radial direction of the sliding axis at all the portions of the plate-like portion 50. One side Z1 in the sliding direction of the plate-like part 50 and the other end of the other side are connected to the pipe structure 17 over the entire circumference around the sliding axis. In this embodiment, the connection part of the both ends of the sliding direction Z of the plate-shaped part 50 and the pipe line structure 17 is connected maintaining airtightness. However, it is not an indispensable configuration to keep the connection between the both end portions of the plate-like portion 50 in the sliding direction Z and the pipe line structure 17 airtight. The space downstream of the cylinder cylindrical portion 24 in the fluid flow direction and upstream of the plate-like portion 50 in the flow direction is referred to as “intermediate space”, and the plate-like portion of the space defined by the pipe structure 17 A space downstream of the flow direction with respect to 50 is referred to as a “downstream space”.

  A plurality of through holes 55 are formed in the plate-like portion 50. The through hole 55 is formed to be openable and closable, and can communicate the upstream space and the downstream space. The through-hole 55 has an axis in the thickness direction of the plate-like portion 50 at each part of the plate-like portion 50. Therefore, the direction of the axis of the through hole 55 coincides with the radial direction with respect to the sliding axis. A portion of the plate-like portion 50 that defines the through hole 55 is referred to as a “through hole defining portion”. The space in the through hole 55 defined by the through hole defining portion 56 is generally formed in a cylindrical shape. The direction of the axis of the cylinder coincides with the radial direction with respect to the sliding axis. In other embodiments, the direction of the axis of the through hole 55 may form an angle with respect to the radial direction with respect to the sliding axis.

  The through-hole 55 is formed in the range of several to several thousand, for example, 10 or more and 1000 or less with respect to the plate-like portion 50. The larger the number of the through holes 55 within this range, the finer the passage resistance for the fluid passing through the through holes 55 can be set. The inner diameter of each through-hole 55 is set, for example, in the range of 1 millimeter (millimeters, abbreviation “mm”) to 10 mm. The smaller the inner diameter of the through-hole 55, the greater the passage resistance for the viscous fluid. In the present embodiment, the inner diameters of the through holes 55 are set equal to each other and set to 3 mm.

  FIG. 5 is a view showing the through hole defining portion 56 and the blocking portion 51 in the first embodiment of the present invention. FIG. 5A is a cross-sectional view of the through hole defining portion 56 taken along a plane including the sliding axis, and FIG. 5B is a side view of the closing portion 51. A female screw is formed in the through hole defining portion 56. The female screw formed in the through hole defining portion 56 is formed with the radial direction with respect to the sliding axis as the axis. The closing part 51 is attached to the plate-like part 50 and closes the through hole 55. The closing part 51 includes a screw base on which a male screw that is screwed into the female screw is formed. In the present embodiment, the closing part 51 is a screw part in which a male screw is formed, for example, a screw with a slit.

  In other embodiments, the closing portion may be configured to further include a washer, for example. In this embodiment, the closing portion 51 is attached to the plate-like portion 50 from the radially outer side with respect to the sliding axis, and the screw base of the closing portion 51 is in contact with the through-hole defining portion 56 and screwed into the female screw. Block 55. Among the plurality of through-hole defining portions 56, the through-hole defining portion 56 that defines the through-hole 55 blocked by the closing portion 51 comes into airtight contact with the closing portion 51. As a result, the fluid is prevented from passing through the through hole 55 blocked by the blocking portion 51. In other embodiments, the contact between the through-hole defining portion 56 and the closing portion 51 is not necessarily kept airtight. When the blocking portion 51 is attached to the through hole defining portion 56, a pressure difference is generated between the upstream side and the downstream side of the silencer 10, and the movement of the fluid causes the closing portion 51 to be fitted to the through hole defining portion 56. If it is not canceled.

  When there is a pressure difference between the fluid pressure in the intermediate space 52 and the fluid pressure in the downstream space 54, the pressure acting on the closing portion 51 from the inside in the radial direction of the sliding axis and the closing portion 51 The pressure acting from the outside of the sliding axis in the radial direction is different. Since the blocking part 51 is screwed into a female screw formed in the through-hole defining part 56, even if different pressures or forces are applied to the blocking part 51 from both directions in the radial direction, the blocking part 51 It is prevented from falling off from the through hole defining portion 56 alone.

  The number of blocking portions 51 is set to be smaller than the number of through holes 55 formed in the plate-like portion 50. Of the through holes 55, the through holes 55 excluding the through holes 55 blocked by the blocking portion 51 communicate the intermediate space 52 and the downstream space 54. Of the through holes 55, the through holes 55 excluding the through holes 55 blocked by the closing portions 51 are referred to as “open holes”, and the portions defining the open holes 57 are referred to as “open hole defining portions”. In a state where a part of the plurality of through holes 55 is blocked by the blocking portion 51, the plate-shaped portion 50 acts as a resistance against the flow of fluid.

  Specifically, the open hole defining portion 58 acts as a resistance against the fluid that moves from the midway space 52 through the open hole 57 to the downstream space 54. Accordingly, the pressure of the fluid in the downstream space 54 becomes smaller than the pressure of the fluid in the intermediate space 52. In the present embodiment, the pressure of the fluid in the downstream space 54 is the secondary pressure P2 (pascal, abbreviated “Pa”), and the secondary pressure P2 (Pa) is equal to the target secondary pressure P2ref (Pa). A state in which the secondary pressure P2 (Pa) is maintained at the target secondary pressure P2ref (Pa) is referred to as a “predetermined state”.

  On the premise that the number of closed portions 51 attached to the through holes 55 is constant without change, that is, the ratio of the open holes 57 among the plurality of through holes 55 is constant. A state where the flow velocity of the fluid moving from the space to the space in the downstream pipe 32, the position of the piston 14 with respect to the cylinder 12, and the secondary pressure are constant is referred to as a “steady state”. For example, when the fluid is consumed on the downstream side of the pressure control device 11 and the flow rate of the fluid in the downstream side pipe 32 becomes higher than the steady state, the secondary pressure is reduced. When the secondary pressure is reduced, if the piston 14 is displaced in one sliding direction Z1, the resistance due to the through hole defining portion exposed to the piston space 49 and the piston 14 is reduced. As a result, the flow rate of the fluid passing through the permeation hole 25 exposed in the piston space 49 increases. Accordingly, the fluid supplied to the downstream space 54 increases and the secondary pressure rises.

  Conversely, on the downstream side of the pressure control device 11, for example, when the consumption of the fluid decreases and the flow rate of the fluid in the downstream pipe 32 becomes slower than the steady state, the secondary pressure increases. When the secondary pressure rises, if the piston 14 is displaced in the other sliding direction Z2, the resistance due to the through hole defining portion exposed to the piston space 49 and the piston 14 increases. As a result, the flow rate of the fluid passing through the permeation hole 25 exposed in the piston space 49 is reduced. Therefore, the fluid supplied to the downstream space 54 decreases and the secondary pressure decreases.

  FIG. 6 is a diagram illustrating the drive unit 19 and the control unit 21 in the first embodiment of the present invention. When the number of the blocking portions 51 attached to the through holes 55 is constant without being changed, that is, when the ratio of the open holes 57 among the plurality of through holes 55 is constant, the secondary pressure is slid on the piston 14. It is adjusted by the displacement in the moving direction Z. The pressure control apparatus 11 according to the first embodiment further includes a control unit 21 and a pressure sensor 62. The control unit 21 maintains a predetermined state in the pipe line by controlling the position of the piston 14 in the sliding direction Z. When the number of the blocking portions 51 attached to the through holes 55 is constant without being changed, that is, when the ratio of the open holes 57 among the plurality of through holes 55 is constant, the control unit 21 controls the piston 14. By determining the position in the sliding direction Z, the difference between the atmospheric pressure and the secondary pressure is determined.

  The pressure sensor 62 is connected to the downstream side pipe 32 by the signal pipe 64 and detects the value of the secondary pressure P2 of the fluid in the downstream side pipe 32. The pressure sensor 62 outputs a detection signal including the detected value of the secondary pressure P2 (Pa) as information to the control unit 21. The control unit 21 detects the pressure of the fluid in the downstream pipe 32 based on the detection signal from the pressure sensor 62.

  The control unit 21 is a part that controls the drive unit 19 in accordance with the detection signal output from the pressure sensor 62. The control unit 21 compares the secondary pressure P2 (Pa) represented by the input detection signal with the target secondary pressure P2ref (Pa) represented by the reference signal, and compares the secondary pressure P2 (Pa) with the target secondary pressure. The magnitude relationship with P2ref (Pa) is determined. When it is determined that the secondary pressure P2 (Pa) is equal to the target secondary pressure P2ref (Pa), the predetermined state is maintained.

  If it is determined that the secondary pressure P2 (Pa) is smaller than the target secondary pressure P2ref (Pa), the piston 14 is displaced in the sliding direction Z1. As a result, the flow rate of the fluid passing through the permeation hole 25 exposed in the piston space 49 increases, and the secondary pressure rises. When it is determined that the secondary pressure P2 (Pa) is larger than the target secondary pressure P2ref (Pa), the piston 14 is displaced in the other sliding direction Z2. As a result, the flow rate of the fluid passing through the permeation hole 25 exposed in the piston space 49 is decreased, and the secondary pressure is decreased.

  As shown in FIG. 1, the fluid in the upstream pipe 31 enters the upstream space 36. The pressure of the fluid in the upstream space 36 is a primary pressure. Next, the fluid passes through the opening 33 and enters the piston space 49. The pressure of the fluid in the piston space 49 is a primary pressure. Next, the fluid passes through the through hole 25 exposed in the piston space 49 and enters the intermediate space 52. In the middle space 52, the pressure of the fluid is lower than the primary pressure and higher than the secondary pressure. Next, the fluid passes through the opening hole 57 and moves to the downstream space 54. In the downstream space 54, the pressure of the fluid is equal to the secondary pressure.

  When the fluid moves in the pressure control device 11, a sound is generated by the movement of the fluid. The pressure varies depending on where the fluid is located. When the fluid moves from the upstream side where the pressure is relatively high to the downstream side where the pressure is low, the volume of the fluid changes. When the pressure of the fluid decreases, the fluid expands, and the more sudden the pressure drop, the more rapidly the fluid expands. Along with this, the fluid flow becomes more turbulent, and the fluid velocity increases and approaches the speed of sound. As a result, vibration is generated in the fluid and sound is generated. When the fluid is a gas, the frequency of the generated sound is often 1 kilohertz (abbreviation “kHz”) to 8 kHz. Since the sound generated in the pressure control device 11 can cause noise, it is desirable to reduce the generation itself.

  When the silencer 10 is not provided, and when the plate-like portion 50 in the first embodiment is provided and all the through holes 55 of the plate-like portion 50 are opened, the fluid moving in the pressure control device 11 is fluid. When moving from the piston space 49 through the transmission hole 25 of the cylinder 12 to the intermediate space 52, the pressure changes the largest and the volume expansion rate becomes the largest. Along with this, the fluid flow becomes more turbulent, and the fluid velocity increases and approaches the speed of sound. Accordingly, sound is generated from the fluid located on the downstream side of the transmission hole 25 in the vicinity of the transmission hole 25. As the plate-like portion 50 is provided and the through-hole 55 of the plate-like portion 50 is closed by the closing portion 51, the pressure difference between the intermediate space 52 partitioned by the silencer 10 and the downstream space 54 becomes larger.

  Since the primary pressure and the secondary pressure are kept at a predetermined pressure by controlling and driving the position of the piston 14 in the sliding axis direction with respect to the cylinder 12, the through hole 55 of the plate-like portion 50 is blocked. The more it is closed by the part 51, the more the permeation hole 25 is opened and exposed to the piston space 49. Thereby, the pressure difference between the piston space 49 and the intermediate space 52 is reduced. The number of blocking portions 51 that block the through holes 55 of the plate-like portion 50 is set manually when the pressure control device 11 is set. With this setting, the pressure difference between the intermediate space 52 and the downstream space 54 is adjusted to be approximately equal to the pressure difference between the piston space 49 and the intermediate space 52.

  Thus, when the silencer 10 is not provided, the pressure changes from the primary pressure to the secondary pressure in one step by passing through the permeation hole 25 from the upstream side of the cylinder cylindrical portion 24 and moving to the downstream side. The fluid pressure change is a two-stage change, that is, a pressure change when moving from the piston space 49 to the intermediate space 52 and a pressure change when moving from the intermediate space 52 to the downstream space 54. As a result, the pressure change that the fluid receives as it moves is not abrupt, and the volume change of the fluid is also reduced at each stage. Therefore, the sound generated as the fluid moves is reduced.

  When the generation of sound is observed from the pressure control device 11, the vibration of the pipe structure 17 may be observed even if the vibration of the pipe structure 17 is observed. . Therefore, by reducing the pressure change accompanying the movement of the fluid and suppressing the volume expansion, the turbulent flow, and the increase of the fluid velocity that are caused by the movement of the fluid, the vibration of the pipe structure 17 is also reduced. . The position of the plate-like portion 50 relative to the cylinder cylindrical portion 24 may be set regardless of the wavelength of sound generated downstream of the cylinder cylindrical portion 24.

  The silencer 10 in the present embodiment suppresses the sound generation itself on the downstream side of the cylinder 12, but even if a sound is generated, the sound is generated by absorbing or reflecting the sound. Suppresses propagation downstream. In this embodiment, the silencer 10 shall be formed with steel materials or resin. Of the pressure control device 11, the portion excluding the silencer 10 and the O-ring 16 is preferably formed of steel.

In this embodiment, the primary pressure is 150 kilopascal (abbreviated as “kPa”), the secondary pressure is 2.3 kPa, the upstream side piping 31 and the downstream side piping 32 are nominal diameters in Table 3 of JIS Industrial Standard G3456. The pipe is defined as 100A. Under this condition, when the silencer 10 according to the present embodiment is provided, the sound pressure of the generated sound is reduced by 10 decibel (abbreviation “dB”) to 20 dB as compared with the case where the silencer 10 is not provided. . The dB as a unit of sound pressure shall be determined using 2 × 10 ⁻⁵ Pascal (abbreviated as “Pa”) as an absolute reference value. About the measurement of the volume of a sound, it measured in accordance with the measuring method prescribed | regulated to Japanese Industrial Standards JIS "Z8731". The result was displayed as a noise level “L _PA (A-weighted sound pressure level, abbreviation“ L _PA ”).

  According to the first embodiment, the silencer 10 includes the plate-like portion 50. The plate-like portion 50 is provided on the downstream side of the fluid flow with respect to the passage hole opened and closed by the displacement of the piston 14 in the conduit through which the fluid flows. The plate-like portion 50 is provided by partitioning a space on the upstream side and a space on the downstream side of the plate-like portion 50, and a plurality of through holes 55 are formed. The through hole 55 is formed to be openable and closable, and can communicate the upstream space and the downstream space. As a result, when the fluid upstream of the plate-like portion 50 moves downstream through the through-hole 55 formed in the plate-like portion 50, the fluid in the space upstream of the plate-like portion 50 is in the space. A pressure difference can be generated between the pressure and the pressure in the downstream space. By closing the plurality of through holes 55 with the plurality of blocking portions 51, the ratio of the through holes 55 that connect the upstream space and the downstream space among all the through holes 55 can be changed. Therefore, the pressure difference between the pressure in the space upstream of the plate-like portion 50 and the pressure on the downstream side can be changed. Thereby, it is possible to increase the passage resistance with respect to the fluid that passes through the through hole 55 from the upstream side of the plate-like portion 50 and moves to the downstream side.

  Accordingly, the pressure difference between the pressure of the fluid upstream of the passage hole and the pressure of the fluid downstream of the passage hole and upstream of the plate-like portion 50 is compared with the case where the plate-like portion 50 is not provided. Can be reduced. Therefore, the volume expansion coefficient when the fluid upstream of the passage hole moves downstream of the passage hole can be reduced as compared with the case where the plate-like portion 50 is not provided. Further, the fluid flow turbulence can be reduced by reducing the pressure difference, and the fluid velocity can be prevented from becoming sonic. As a result, the sound generated when the fluid upstream of the passage hole moves downstream of the passage hole can be reduced.

  Moreover, according to 1st Embodiment, the plate-shaped part 50 is formed in the cylinder shape which has an axis line in the displacement direction of piston 14, and encloses the cylinder 12 with which piston 14 fits. Accordingly, the plate-like portion 50 can perform at least one of inward reflection and absorption with respect to the sound generated in the vicinity of the piston 14 as the fluid passes through the passage hole. Further, the plate-like portion 50 can suppress the sound generated in the vicinity of the piston 14 from being transmitted to a pipe line positioned radially outward from the plate-like portion 50 with respect to the axis of the piston 14. Therefore, it is possible to suppress the sound generated in the vicinity of the piston 14 from being transmitted outward from the pipe line.

  According to the first embodiment, the closing part 51 is attached to the plate-like part 50 and closes the through hole 55. An internal thread is formed on the inner wall that defines the through hole 55. The closing part 51 includes a screw base in which a male screw that is screwed into the female screw is formed. Therefore, the screw base can be screwed into the female screw. As a result, at least a part of the plurality of through holes 55 can be blocked by the plurality of blocking portions 51. Thereby, the ratio of the through-hole 55 which connects the upstream space and the downstream space among the plurality of through-holes 55 can be changed. Therefore, it is possible to adjust the pressure difference between the pressure of the fluid upstream of the plate-like portion 50 and the pressure of the fluid downstream. As a result, the sound generated when the fluid upstream of the passage hole moves downstream of the passage hole and upstream of the plate-like portion 50 and the fluid upstream of the plate-like portion 50 are It is possible to reduce the sound generated by moving downstream from the plate-like portion 50.

  The permeation hole 25 in the other sliding direction Z2 of the cylinder cylindrical portion 24 is exposed to the piston space 49 more frequently than the permeation hole 25 in the one sliding direction Z1 of the cylinder cylindrical portion 24, and the frequency of fluid passage is higher. high. Therefore, the frequency that the fluid in the downstream side of the cylinder cylindrical portion 24 and in the vicinity of the cylinder cylindrical portion 24 becomes a sound source is higher in the vicinity of the other sliding direction Z2 than in the sliding direction one Z1. Therefore, in the silencer 10, it is preferable that the reflectance and absorption rate for sound be higher in the vicinity of the other sliding direction Z2 than in the sliding direction one Z1. The plurality of through-holes 55 formed in the plate-like portion 50 are located so as to spread evenly in both the sliding direction Z and the circumferential direction. Among the plurality of through holes 55, the through hole 55 located near the other side Z <b> 2 in the cylinder cylindrical portion 24 is closed by the closing portion 51. Of the through holes 55 of the plate-like portion 50, the through hole 55 closest to the transmission hole 25 located in the other sliding direction Z 2 of the cylinder cylindrical portion 24 is closed by the closing portion 51, thereby being exposed to the piston space 49. The sound generated at the downstream side of the transmitting hole 25 is absorbed and / or reflected by the plate-like portion 50 and the closing portion 51.

  Further, according to the first embodiment, the pressure control device 11 includes the silencer 10. As a result, a pressure difference can be generated between the pressure in the space upstream of the silencer 10 and the pressure in the downstream space. Moreover, the ratio of the through-hole 55 which connects the space upstream from the silencer 10 and the space downstream is among the through-holes 55 of the silencer 10 can be changed. Thereby, the pressure difference between the pressure in the space upstream of the silencer 10 and the pressure in the downstream space can be changed. Therefore, the pressure difference between the pressure of the fluid upstream of the passage hole and the pressure of the fluid downstream of the passage hole and upstream of the silencer 10 is smaller than when the plate-like portion 50 is not provided. can do. As a result, the volume expansion coefficient when the fluid upstream of the passage hole moves downstream of the passage hole can be made smaller than when the plate-like portion 50 is not provided. Further, the fluid flow turbulence can be reduced by reducing the pressure difference, and the fluid velocity can be prevented from becoming sonic. As a result, the noise generated when the fluid upstream of the passage hole moves downstream of the passage hole can be reduced.

Second Embodiment
FIG. 7 is a cross-sectional view of the plate-like portion 50 in the second embodiment of the present invention. The silencer 10 according to the second embodiment is similar to the silencer 10 according to the first embodiment, and will be described below with a focus on differences between the second embodiment and the first embodiment. The plate-like portion 50 is formed in a flat plate shape, and the plate-like portion 50 includes two members formed away from each other in the fluid flow direction. The plate-like portion 50 is disposed on the downstream side of the cylinder cylindrical portion 24. Of the two members included in the plate-like portion 50, the upstream member 66 is on the upstream side in the fluid flow direction, and the downstream member 68 is the fluid. It is arrange | positioned in the flow direction downstream.

  The upstream side member 66 and the downstream side member 68 are arranged in the pipe line structure 17 in which the fluid flow direction and the flow path direction one X1 coincide with each other, and are perpendicular to the flow direction. The outer shape is formed in a circular shape corresponding to the cross-sectional shape and size of a simple pipe. The outer edge portion when the upstream member 66 and the downstream member 68 are viewed in the flow direction is installed in close contact with the pipe line structure 17. The distances of the upstream member 66 and the downstream member 68 from the cylinder cylindrical portion 24 may be set regardless of the wavelength of sound generated downstream of the cylinder cylindrical portion 24. The distance between the upstream member 66 and the downstream member 68 that are separated in the flow direction may also be set regardless of the wavelength of the sound that is generated.

  The plurality of through holes 55 formed in the upstream side member 66 and the downstream side member 68 are located so as to spread evenly when viewed in the flow direction. The plurality of through holes 55 are formed in a circular shape when viewed in the flow direction, and the direction of the axis of the through hole 55 coincides with the flow direction.

  The through hole 55 formed in the downstream member of the two members of the plate-like portion 50 and communicating the upstream space and the downstream space avoids the projection region 69 formed in the downstream member. , Formed in a region around the projection region 69. The projection area 69 is an area formed by projecting a through hole 55 formed in the upstream member and communicating the upstream space and the downstream space onto the downstream member.

  The positions of the plurality of through holes 55 formed in each of the upstream side member 66 and the downstream side member 68 are spread vertically and perpendicularly to the flow direction. In the member 66 and the downstream side member 68, a densely arranged region and a sparsely arranged region are formed. A region where the blocking portions 51 are densely arranged is referred to as a “dense region”, and a region where the closed portions 51 are sparsely arranged is referred to as a “sparse region”. The dense region 72 and the sparse region 74 may be formed in any shape as viewed in the flow direction, but in the present embodiment, each is formed in a checkered pattern shape.

  In the present embodiment, a region formed by projecting the sparse region 74 formed on the upstream member 66 onto the downstream member 68 is the projection region 69. In the projection region 69, a dense region 72 is formed in the downstream member 68. In the region formed by projecting the dense region 72 formed in the upstream member 66 onto the downstream member 68, a sparse region 74 in the downstream member 68 is formed. In the region where the open hole 57 of the upstream member 66 is projected onto the downstream member 68, the blocking portion 51 is disposed in the downstream member 68. As a result, the sound that has passed through the open hole 57 of the upstream member 66 is either absorbed or reflected by the downstream member 68.

  The area of the dense region 72 formed in the downstream member 68 is preferably set larger than the area of the dense region 72 formed in the upstream member 66. By passing through the opening hole 57 of the upstream member 66 in the flow direction, there is a difference in fluid pressure between the upstream side and the downstream side across the upstream member 66. Further, by passing through the opening hole 57 of the downstream member 68 in the flow direction, a difference occurs in the fluid pressure between the upstream side and the downstream side across the downstream member 68. Although the pressure of the fluid flowing in the pressure control device 11 in the first embodiment is reduced in two stages from the upstream side to the downstream side, the pressure of the fluid flowing in the pressure control device 11 in the second embodiment is The pressure is reduced in three stages: an upstream side and a downstream side sandwiching the cylinder cylindrical portion 24, an upstream side and a downstream side sandwiching the upstream member 66, and an upstream side and a downstream side sandwiching the downstream member 68.

  Since the primary pressure and the secondary pressure are set in advance, if the pressure difference generated in these three stages is equal, the pressure difference generated in each stage is larger than the pressure difference generated in each stage in the first embodiment. Get smaller. As a result, the volume expansion coefficient of the fluid becomes smaller than when the pressure difference is large. Accordingly, the fluid flow disturbance is reduced, and the fluid velocity is prevented from approaching the sonic velocity. Therefore, the generation of sound is suppressed.

  When the position of the piston 14 in the sliding direction Z with respect to the cylinder cylindrical portion 24 is constant, the pressure difference between the upstream side and the downstream side sandwiching the upstream side member 66 and the upstream side and the downstream side sandwiching the downstream side member 68 are If the total pressure difference with the pressure difference increases, the secondary pressure decreases. The drive unit 19 keeps the secondary pressure constant by displacing the piston 14 in the sliding direction Z. Therefore, if the pressure difference between the upstream side and the downstream side of the silencer 10 increases, the piston 14 moves in the sliding direction. Z1 is displaced, and the pressure difference between the upstream side and the downstream side of the cylinder cylindrical portion 24 becomes small. The pressure difference between the upstream side and the downstream side sandwiching the cylinder cylindrical portion 24 is adjusted by adjusting the number of the closed portions 51 arranged with respect to the through hole 55 of the upstream member 66 and the through hole 55 of the downstream member 68. The pressure difference between the upstream side and the downstream side across the upstream member 66 and the pressure difference between the upstream side and the downstream side across the upstream member 66 are set to the same pressure difference. Thereby, the pressure difference accompanying the movement of the fluid is reduced, the rapid expansion of the fluid is suppressed, and the generation of sound due to the rapid expansion is suppressed.

  According to 2nd Embodiment, the plate-shaped part 50 is formed in flat form. Accordingly, the plate-like portion 50 is located in the pipe line on the downstream side of the passage hole, and can partition the upstream side and the downstream side of the pipe line. Therefore, at least one of reflection and absorption to the upstream side can be performed on the sound generated in the vicinity of the piston 14 due to the fluid passing through the passage hole. By installing the plate-like portion 50 downstream of the passage hole, it is possible to suppress the sound from being transmitted to the downstream side. Further, since the plate-like portion 50 is formed in a flat plate shape, the plate-like portion 50 is downstream of the cylinder 12 as compared with the case where the plate-like portion 50 is formed as a cylindrical plate-like portion 50 material surrounding the cylinder 12. It can be set apart from the cylinder 12. Therefore, restrictions on the structure and dimensions of the cylinder 12 can be eliminated. Thereby, the freedom degree of design of a pipe line can be made high. Moreover, the structure of the plate-shaped part 50 can be simplified compared with the case where the plate-shaped part 50 is formed in a cylinder shape. Thereby, manufacture of the plate-shaped part 50 can be made easy.

  Further, according to the second embodiment, the plate-like portion 50 includes two members that are formed apart from each other in the fluid flow direction. Of the two members, the downstream member can perform at least one of reflection and absorption with respect to the sound generated in the vicinity of the piston 14 and transmitted through the upstream member. Moreover, it can suppress transmitting the sound which generate | occur | produces in the piston 14 vicinity to the outward of a pipe line compared with the case where the plate-shaped part 50 is formed as one member.

  Further, according to the second embodiment, the through hole 55 formed in the downstream member of the two members and communicating the upstream space and the downstream space is the projection region formed in the downstream member. It is formed in an area around the projection area 69 while avoiding the area 69. The projection area 69 is an area formed by projecting a through hole 55 formed in the upstream member and communicating the upstream space and the downstream space onto the downstream member. As a result, compared with the case where at least a part of the through hole 55 formed in the downstream member is formed in the projection region 69, the sound that has passed through the through hole 55 formed in the upstream member is The possibility that the member on the side reflects or absorbs toward the upstream side can be increased. Accordingly, it is possible to reduce the possibility that the sound generated near the piston 14 and transmitted through the through hole 55 formed in the upstream member passes through the through hole 55 formed in the downstream member.

<Third Embodiment>
FIG. 8 is a diagram illustrating the through hole 55 and the blocking portion 51 in the third embodiment of the present invention. FIG. 8A is a cross-sectional view of the through-hole defining portion 56 formed in the plate-like portion 50 taken along a cutting plane including the axis of the through-hole 55, and FIG. FIG. 8C is a side view of the through hole defining portion 56 formed in the shape portion 50 when viewed in the axial direction of the through hole 55, and FIG. 8C is a perspective view of the closing portion 51. The silencer 10 according to the third embodiment is similar to the silencer 10 according to the first embodiment, and will be described below with a focus on differences between the third embodiment and the first embodiment.

  The blocking portion 51 in the third embodiment is inserted into the through-hole 55 from the radially outer side with respect to the sliding axis in the through-hole 55, and is displaced in the radial direction by an angle of 90 degrees around the axis of the through-hole 55. Is fixed. As a result, even if there is a difference between the pressure of the fluid radially inward of the closed portion 51 and the pressure of the fluid radially outward, the closed portion 51 is prevented from being displaced in the radial direction.

  The closing part 51 includes a head part 76 and a shaft part 77 as shown in FIG. The shaft portion 77 is formed in a columnar shape, and one of the two bottom portions of the column is connected to the head portion 76. When viewed in the axial direction of the cylinder, the outer diameter of the head portion 76 is formed larger than the outer diameter of the shaft portion 77. From the side surface of the shaft portion 77, a convex portion 78 protruding in the radial direction with respect to the axis of the cylinder is formed. The convex part 78 is a rod-shaped part formed so as to project in two directions in a linear direction perpendicular to the axis of the cylinder, and the diameter of the rod of the convex part 78 is formed smaller than the outer diameter of the cylinder. The diameter of the rod of the convex portion 78 is set smaller than the thickness in the radial direction with respect to the sliding axis of the plate-like portion 50.

  In addition to the hole formed corresponding to the shaft portion 77 of the closing portion 51, the through-hole 55 has a groove into which the convex portion 78 can enter on the assumption that the closing portion 51 is inserted in a predetermined posture. It is formed. The closing portion 51 is a through hole in a posture in which the head portion 76 is directed radially outward and the shaft portion 77 is directed radially inward from the radially outer side with respect to the sliding direction Z with respect to the plate-like portion 50. 55 is inserted. When the protruding portion is inserted to the central portion in the radial direction with respect to the sliding axis among the thickness of the plate-like portion 50, the protruding portion comes into contact with the through hole defining portion 56. From this state, the closing portion 51 is displaced by an angle of 90 degrees around the axis of the shaft portion 77. The direction in which the closing portion 51 is angularly displaced is a predetermined direction in the circumferential direction, and the plate-like portion 50 is formed with an internal groove corresponding to the entrance of the shaft portion 77.

  Since the closing part 51 is attached to the plate-like part 50 by being angularly displaced by 90 degrees, compared to the case where the closing part 51 is screwed to the through-hole defining part 56, the closing part 51 is attached. Therefore, the angle of the closing portion 51 can be reduced. Therefore, the time for attaching the closing portion 51 to the plate-like portion 50 can be shortened. As a result, it is possible to reduce the time required for arranging and adjusting the blocking portion 51 with respect to the through-hole defining portion 56.

<Fourth embodiment>
FIG. 9 is a diagram illustrating the through hole 55 and the blocking portion 51 in the fourth embodiment of the present invention. FIG. 9A is a perspective view of the through-hole defining portion 56 formed in the plate-like portion 50, and FIG. 9B slides the through-hole defining portion 56 formed in the plate-like portion 50. FIG. 9C is a cross-sectional view when viewed in the radial direction with respect to the axis, and FIG. The silencer 10 according to the fourth embodiment is similar to the silencer 10 according to the first embodiment, and will be described below with a focus on differences between the third embodiment and the first embodiment.

  The through hole 55 in the fourth embodiment is formed as a rectangular hole that penetrates the plate-like portion 50 in the radial direction. The area when the space in the through hole 55 is viewed in the thickness direction of the plate-like portion 50 is referred to as “opening area”. The closing part 51 has an area larger than the opening area of the through hole 55 and is formed in a rectangular shape that can close the through hole 55. A rib 81 that fixes the position of the blocking portion 51 in the radial direction is formed on the outer side in the radial direction with respect to the sliding axis of the through hole defining portion 56. In a state where the blocking portion 51 blocks the through hole 55 from the outside in the radial direction, a part of the outer edge portion of the blocking portion 51 is sandwiched in the radial direction by a portion of the through hole defining portion 56 and a portion of the rib 81. The Specifically, a part of the short side of the rectangle is opened so that the blocking portion 51 can be inserted, and the blocking portion 51 is sandwiched between the remaining three sides.

  Assuming that the fluid is viscous, even if the opening area is the same, the smaller each through hole 55 is, the larger the shape of each through hole 55 is from the shape of a circle. The more the resistance of the through hole defining portion 56 against the fluid passing through the through hole 55 is, the greater the value is. By changing the shape of the through hole 55 from a circular shape to a flat rectangular shape, it is possible to close a wide opening area with one closed portion 51 and in one step, compared with the case where a large number of circular through holes 55 are formed. It becomes.

<Modification>
In the first embodiment, the drive unit 19 is configured to be electrically controlled. However, in other embodiments, the drive unit 19 may be configured not to use the electric power and the electric motor 46. For example, in another embodiment, the control unit may include a diaphragm that uses the primary pressure, the secondary pressure, and the elastic restoring force of the spring, and the drive unit 19 includes the primary pressure, the secondary pressure, and the spring. It is good also as a structure controlled by the diaphragm which operate | moves with the elastic restoring force of this, and operate | moves using the differential pressure | voltage of a primary pressure and a secondary pressure as a drive source. In the second embodiment, the dense region 72 and the sparse region 74 form a checkered pattern. However, in other embodiments, for example, the dense region and the sparse region may be a striped pattern.

  In the first, third and fourth embodiments, the silencer 10 is installed at one location downstream of the cylinder cylindrical portion 24. In the second embodiment, the silencer 10 is installed at two locations separated in the flow direction. It was supposed to be. Furthermore, in other embodiment, the silencer 10 is good also as a structure installed in three places away in a flow direction. In addition, it is preferable that the pressure of the fluid gradually decreases through four or more stages as it goes from the upstream side to the downstream side. The smaller the amount of change in pressure associated with movement in the fluid flow direction, the more rapid volume expansion can be suppressed, and the fluid flow disturbance can be reduced by reducing the pressure difference. In addition, the fluid velocity can be prevented from becoming sonic. Therefore, the generation of sound can be suppressed.

  In the first to fourth embodiments, the passage hole is the transmission hole 25 formed in the cylinder cylindrical portion. However, in another embodiment, the piston comes into contact with or separates from the opening of the partition wall. When the pressure difference between the pressure on the upstream side and the pressure on the downstream side of the partition wall is adjusted, the opening of the partition wall is used as a passage hole. Even in such a configuration, the same effect can be achieved by providing a silencer on the downstream side of the passage hole.

  In the first to fourth embodiments, the fluid is located on the downstream side on the side where the piston is located and the opposite side of the piston is located on the upstream side. However, in other embodiments, the fluid is located on the side of the partition. The upstream side may be the upstream side, and the opposite side of the partition with respect to the piston may be the downstream side. In this case, the opening formed in the partition wall is used as a passage hole, and the silencer is disposed on the downstream side of the opening formed in the partition wall.

It is sectional drawing of the pressure control apparatus 11 which concerns on 1st Embodiment of this invention. It is sectional drawing which looked at the pressure control apparatus 11 which concerns on 1st Embodiment of this invention cut | disconnected by the AA cross section of FIG. It is a perspective view of the plate-shaped part 50 in 1st Embodiment of this invention. It is sectional drawing which looked at the plate-shaped part 50 in 1st Embodiment of this invention cut | disconnected by the plane containing a sliding axis. It is a figure which shows the through-hole prescription | regulation part 56 and the obstruction | occlusion part 51 in 1st Embodiment of this invention. It is a figure showing the drive part 19 and the control part 21 in 1st Embodiment of this invention. It is sectional drawing of the plate-shaped part 50 in 2nd Embodiment of this invention. It is a figure showing the through-hole 55 and the obstruction | occlusion part 51 in 3rd Embodiment of this invention. It is a figure showing the through-hole 55 and the obstruction | occlusion part 51 in 4th Embodiment of this invention. It is sectional drawing of the high voltage | pressure governor 2 containing the silencer 1 which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Silencer 11 Pressure control apparatus 12 Cylinder 14 Piston 17 Pipe line structure 19 Drive part 21 Control part 25 Permeation hole 28 Partition 33 Opening 36 Upstream space 49 Piston space 50 Plate-shaped part 51 Closure part 52 Intermediate space 54 Downstream space 55 Through hole 66 Upstream member 68 Downstream member 69 Projection area

Claims (8)

In the pipeline through which the fluid flows, it is provided on the downstream side with respect to the fluid flow than the passage hole opened and closed by the displacement of the piston,
Provided by partitioning the upstream space and the downstream space,
A silencer, comprising: a plate-like portion in which a plurality of through holes capable of communicating with an upstream space and a downstream space are formed so as to be closed.   The silencer according to claim 1, further comprising a plurality of closing portions attached to the plate-like portion and closing the through hole. The plate-like portion is
Formed in a cylindrical shape having an axis in the displacement direction of the piston,
The silencer according to claim 1 or 2, wherein a cylinder to which the piston is fitted is surrounded. The plate-like portion is
The silencer according to claim 1 or 2, wherein the silencer is formed in a flat plate shape.   The silencer according to any one of claims 1, 2, and 4, wherein the plate-like portion includes two members formed apart from each other in the fluid flow direction.   A through hole formed in the downstream member of the two members to communicate the upstream space and the downstream space is formed in the upstream member so that the upstream space and the downstream space are connected to each other. The silencer according to claim 5, wherein the communicating through hole is formed in an area around the projection area, avoiding a projection area formed by being projected onto the downstream member. An internal thread is formed on the inner wall that defines the through hole,
The silencer according to any one of claims 2 to 6, wherein the closing portion includes a screw base on which a male screw that is screwed into the female screw is formed.   A pressure control device comprising the silencer according to claim 1.

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