JP6340145B2 - Steam supply system - Google Patents

Description

  The technology disclosed herein relates to a steam supply system.

  Conventionally, a steam supply system used for steam use facilities such as a steam plant is known. For example, the steam supply system described in Patent Literature 1 includes a reevaporation tank, an ejector, a suction path that connects the reevaporation tank and the ejector, and a check valve provided in the suction path. The re-evaporation tank re-evaporates the stored condensate. The ejector sucks the re-evaporated vapor from the re-evaporation tank through the suction path, mixes the drive vapor and the re-evaporated vapor, and flows them out. The mixed steam flowing out from the ejector is supplied to the steam using device. Since a check valve is provided in the suction path, the backflow of steam from the ejector to the re-evaporation tank is prevented.

JP 2007-332859 A

  The aforementioned check valve can be closed when the pressure in the reevaporation tank decreases. For example, when there is little condensate and re-evaporated vapor in the re-evaporation tank, the pressure in the re-evaporation tank may be reduced by suction of the re-evaporated vapor. When the differential pressure between the upstream side and the downstream side of the check valve is lower than the valve opening pressure of the check valve, the check valve is closed. Thereafter, a small amount of condensate remaining in the re-evaporation tank is re-evaporated, or condensate newly introduced into the re-evaporation tank is re-evaporated, and re-evaporated steam is generated in the re-evaporation tank. When the pressure in the re-evaporation tank rises due to the generation of re-evaporated vapor and the differential pressure between the upstream and downstream sides of the check valve exceeds the check valve opening pressure, the check valve opens and re-evaporates. The re-evaporated vapor in the tank begins to be sucked into the ejector through the suction path. When the check valve is opened, the re-evaporation vapor in the re-evaporation tank is sucked all at once, so that the pressure in the re-evaporation tank can rapidly decrease. Then, the check valve is closed again. As a result, a phenomenon in which the check valve is repeatedly opened and closed at a high speed, that is, a chattering phenomenon may occur.

  The technology disclosed herein has been made in view of such a point, and an object thereof is to suppress the chattering phenomenon of the check valve.

  The steam supply system disclosed herein includes a re-evaporation tank for storing condensate and re-evaporated steam, a suction path connected to the re-evaporation tank, a suction path connected to the suction path, and a re-evaporation tank in the re-evaporation tank. An ejector that sucks the evaporated vapor through the suction path and flows it out along with the driving steam, and the suction path is provided with a first check valve that prevents a reverse flow of the steam from the ejector to the re-evaporation tank. A first check valve that includes a main flow path, and a bypass passage that is provided with a second check valve that prevents backflow of steam from the ejector to the re-evaporation tank, and bypasses the first check valve. Has a first opening through which steam flows and a first valve body that opens and closes the first opening, and is configured such that the first valve body opens the first opening at a predetermined first valve opening pressure. The second check valve is smaller than the first opening. , A second opening through which the steam flows and a second valve body for opening and closing the second opening, and the second valve body at the second valve opening pressure smaller than the first valve opening pressure. It is configured to open the opening.

  According to the technique disclosed here, the chattering phenomenon of the check valve can be suppressed.

FIG. 1 is a schematic diagram of a steam supply system. FIG. 2 is a longitudinal sectional view of the first check valve. FIG. 3 is a longitudinal sectional view of the second check valve.

  Hereinafter, exemplary embodiments will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram of a steam supply system. The steam supply system 100 is used in a steam using facility and supplies steam to a steam using apparatus. The steam supply system 100 includes a steam supply path 10 that supplies steam to a steam using device, a pressure reducing valve 11 provided in the steam supply path 10, and an ejector 20 provided downstream of the pressure reducing valve 11 in the steam supply path 10. A re-evaporation tank 30 that stores and re-evaporates condensate, and a suction path 40 that connects the ejector 20 and the re-evaporation tank 30. The steam system 100 sucks the re-evaporated steam in the re-evaporation tank 30 to the ejector 20 by the drive steam flowing into the ejector 20 through the pressure reducing valve 11, and supplies the mixed steam of the drive steam and the re-evaporated steam to the steam using device. To do.

  The upstream end of the steam supply path 10 is connected to a driving steam supply source. The pressure reducing valve 11 decompresses the driving steam and causes the driving steam to flow into the inflow portion 21 of the ejector 20.

  The re-evaporation tank 30 stores the condensate and re-evaporates the condensate. The re-evaporation tank 30 is connected to a condensate inflow passage 31 through which condensate flows and a condensate discharge passage 32 through which condensate is discharged. The condensate discharge path 32 is connected to the lower part of the reevaporation tank 30. A steam trap 33 is provided in the condensate discharge path 32.

  One end of the supply path 40 is connected to the upper part of the reevaporation tank 30. The other end of the suction path 40 is connected to the suction part 22 of the ejector 20. The suction passage 40 includes a main passage 41 provided with a first check valve 50 and a bypass passage 42 that bypasses the first check valve 50 with steam. The first check valve 50 prevents the flow of steam from the ejector 20 toward the reevaporation tank 30, that is, the backflow of steam. That is, in the main flow path 41, the steam flows only in one direction from the reevaporation tank 30 toward the ejector 20.

  The bypass passage 42 connects a portion of the main flow path 41 closer to the reevaporation tank 30 than the first check valve 50 and a portion of the main flow path 41 closer to the ejector 20 than the first check valve 50. Yes. The bypass passage 42 is formed by a tube that is thinner than the main passage 41. A second check valve 60 is provided in the bypass passage 42. The second check valve 60 prevents the flow of steam from the ejector 20 toward the reevaporation tank 30, that is, the backflow of steam. That is, in the bypass path 42, the steam flows only in one direction from the reevaporation tank 30 toward the ejector 20. Further, the bypass passage 42 is provided with a needle valve 70 that adjusts the flow rate of the steam flowing through the bypass passage 42. The needle valve 70 is an example of a control valve.

  FIG. 2 is a longitudinal sectional view of the first check valve 50. The first check valve 50 includes a casing 51 formed with a first opening 51A through which steam flows, a first disk valve 52 that opens and closes the first opening 51A, a guide 53 that guides the first disk valve 52, A coil spring 54 that biases the first disk valve 52 in the closing direction and a pressing member 55 that supports the coil spring 54 are provided. The first disc valve 52 is an example of a first valve body.

  The casing 51 is formed in a substantially cylindrical shape. The casing 51 is open at both ends in the axial direction, and one opening is the first opening 51A. A plurality of guides 53 are provided inside the casing 51. The guides 53 are arranged at intervals in the circumferential direction of the casing 51. The first disc valve 52 is housed in the casing 51 in a state where it can move in the axial direction of the casing 51, specifically, in a state surrounded by a plurality of guides 53.

  In the first check valve 50, the first disk valve 52 closes the first opening 51 </ b> A by the biasing force of the coil spring 54. A pressure against the biasing force of the coil spring 54 acts on the first disk valve 52, so that the first disk valve 52 opens the first opening 51A. Hereinafter, the pressure required to open the first disc valve 52 is referred to as “first valve opening pressure”.

  FIG. 3 is a longitudinal sectional view of the second check valve 60. The second check valve 60 includes a casing 61 having a second opening 61A through which steam flows, a second disk valve 62 for opening and closing the second opening 61A, a guide 63 for guiding the second disk valve 62, And a pressing member 65 for receiving the second disk valve 62 when the valve is opened. The second disc valve 62 is an example of a second valve body.

  The casing 61 is formed in a substantially cylindrical shape. The casing 61 is open at both ends in the axial direction, and one opening is a second opening 61A. The second opening 61A is smaller than the first opening 51A. A plurality of guides 63 are provided inside the casing 61. The guides 63 are arranged at intervals in the circumferential direction of the casing 61. The second disc valve 62 is accommodated in the casing 61 so as to be movable in the axial direction of the casing 61, specifically, surrounded by a plurality of guides 63.

  The second check valve 60 is arranged with the second opening 61A facing downward. Therefore, in the second check valve 60, the second disk valve 62 closes the second opening 61A by its own weight. The second disk valve 62 opens the second opening 61 </ b> A by the pressure against the weight of the second disk valve 62 acting on the second disk valve 62. Hereinafter, the pressure required to open the second disc valve 62 is referred to as “second valve opening pressure”. Since the second check valve 60 is not provided with the coil spring 54 unlike the first check valve 50 and is closed only by its own weight of the second disk valve 62, the second valve opening pressure is Smaller than 1 valve opening pressure.

  Next, the operation of the steam supply system 100 configured as described above will be described.

  Condensate flows into the reevaporation tank 30 via the condensate supply path 31. Condensate stored in the re-evaporation tank 30 is re-evaporated to become steam. The reevaporated vapor stays in the upper part of the reevaporation tank 30. A part of the condensate stored in the reevaporation tank 30 is discharged from the reevaporation tank 30 via the condensate discharge path 32.

  On the other hand, the driving steam flowing through the steam supply path 10 is decompressed by the decompression valve 11 and flows into the inflow portion 21 of the ejector 20. The ejector 20 sucks re-evaporated steam from the re-evaporating tank 30 through the suction path 40 due to the negative pressure generated by the jet pump effect of the driving steam. The ejector 20 mixes the driving steam and the re-evaporated steam, and supplies the mixed steam to the steam using device. At this time, since the first check valve 50 is provided in the main flow path 41 of the suction path 40 and the second check valve 60 is provided in the bypass path 42, steam from the ejector 20 to the reevaporation tank 30 is provided. The backflow is prevented.

  Furthermore, since the bypass passage 42 is provided in the suction passage 40 and the second check valve 60 having a lower valve opening pressure than the first check valve 50 is provided in the bypass passage 42, the first check valve The so-called chattering phenomenon, in which 50 repeatedly opens and closes at high speed, is suppressed.

  Specifically, in the configuration in which the bypass passage 42 and the second check valve 60 are not provided, for example, chattering may occur when there is little reevaporated vapor in the reevaporation tank 30. Specifically, when there is little condensate and reevaporated vapor in the reevaporation tank 30, the pressure in the reevaporation tank 30 is lowered. When the differential pressure between the upstream side and the downstream side of the first check valve 50 is less than the first valve opening pressure, the first check valve 50 is closed. Thereafter, when the condensate stored in the re-evaporation tank 30 re-evaporates, or when the condensate newly flowing into the re-evaporation tank 30 re-evaporates, re-evaporated steam is generated in the re-evaporation tank 30. The pressure in the reevaporation tank 30 increases. When the differential pressure between the upstream side and the downstream side of the first check valve 50 reaches the first valve opening pressure, the first check valve 50 opens, and the re-evaporated vapor in the re-evaporation tank 30 passes through the suction path 40. Via the ejector 20. When the first check valve 50 is opened, the re-evaporated vapor in the re-evaporation tank 30 is sucked at once. When the re-evaporation steam in the re-evaporation tank 30 decreases at a stretch, the pressure in the re-evaporation tank 30 rapidly decreases in a situation where there are few re-evaporation steam and condensate in the re-evaporation tank 30. Then, the first check valve 50 is closed again. As a result, the opening and closing of the first check valve 50 can be repeated at high speed. Thus, a chattering phenomenon occurs.

  On the other hand, a bypass passage 42 is provided in the suction passage 40, and a second check valve 60 is provided in the bypass passage 42. The second valve opening pressure is set lower than the first valve opening pressure. Therefore, when the pressure in the reevaporation tank 30 rises after the first check valve 50 and the second check valve 60 are closed, the differential pressure between the upstream side and the downstream side of the second check valve 60 is second opened. When the valve pressure is reached, the second check valve 60 is opened, and the reevaporated vapor in the reevaporation tank 30 starts to be sucked into the ejector 20 via the bypass passage 42.

  Until the differential pressure between the upstream side and the downstream side of the first check valve 50 reaches the first valve opening pressure, the first check valve 50 is kept closed, and the re-evaporated steam via the bypass passage 42 is maintained. The suction is continued.

  When the pressure in the reevaporation tank 30 further rises and the differential pressure between the upstream side and the downstream side of the first check valve 50 reaches the first valve opening pressure, the first check valve 50 opens, The re-evaporated vapor in the evaporation tank 30 starts to be further sucked into the ejector 20 through the main channel 41.

  When the differential pressure between the upstream side and the downstream side of the first check valve 50 reaches the first valve opening pressure, compared with the case where the bypass passage 42 is not provided, The amount of condensate is increasing. Therefore, even if the first check valve 50 is opened and the re-evaporated vapor in the re-evaporation tank 30 is sucked all at once, the rapid decrease in the pressure in the re-evaporation tank 30 is alleviated, and the first check valve 50 Is closed immediately. As a result, the chattering phenomenon of the first check valve 50 is suppressed.

  Furthermore, since the second opening 61A of the second check valve 60 is smaller than the first opening 51A of the first check valve 50, the flow rate of the re-evaporated steam via the bypass passage 42 is via the main passage 41. Less than the flow rate of reevaporated steam. When the pressure in the re-evaporation tank 30 is lower than the first valve opening pressure, the re-evaporation vapor and the condensate in the re-evaporation tank 30 are relatively small, but the re-evaporation vapor is also sucked in a small amount. A rapid decrease in the re-evaporated vapor in 30 is suppressed. Thereby, the rapid pressure drop in the re-evaporation tank 30 is suppressed, and consequently the chattering phenomenon of the second check valve 60 is also suppressed.

  In addition, the flow rate of the bypass passage 42 can be adjusted by the needle valve 70. As described above, even if the flow rate of the re-evaporated steam in the bypass passage 42 is reduced by reducing the second opening 61A, the actual use status of the steam-using facility (for example, the condensate to the re-evaporating tank 30). Depending on the amount of inflow, etc., the re-evaporated steam and the condensate in the re-evaporation tank 30 may become very small. Therefore, in such a case, the flow rate of the re-evaporated steam in the bypass passage 42 is further reduced by restricting the needle valve 70. Thereby, since re-evaporated steam or condensate in the re-evaporation tank 30 is secured, the chattering phenomenon of the second check valve 60 is further suppressed.

  As described above, the vapor supply system 100 includes the re-evaporation tank 30 that stores condensate and re-evaporated vapor, the suction path 40 connected to the re-evaporation tank 30, and the suction path 40. And an ejector 20 that sucks the re-evaporated vapor from the ejector 20 through the suction path 40 and flows out together with the drive steam. The suction path 40 prevents the reverse flow of the steam from the ejector 20 to the re-evaporation tank 30. A main flow path 41 provided with a valve 50 and a bypass passage 42 provided with a second check valve 60 for preventing the backflow of steam from the ejector 20 to the re-evaporation tank 30 and bypassing the first check valve 50. The first check valve 50 includes a first opening 51A through which steam flows and a first disk valve 52 (first valve body) that opens and closes the first opening 51A, and has a predetermined first valve opening pressure. The first disc valve 52 is in the first opening 51. The second check valve 60 includes a second opening 61A through which steam flows, which is smaller than the first opening 51A, and a second disc valve 62 (second opening) that opens and closes the second opening 61A. The second disc valve 62 is configured to open the second opening 61A at a second valve opening pressure smaller than the first valve opening pressure.

  According to this configuration, the re-evaporated steam in the re-evaporating tank 30 is sucked into the ejector 20, mixed with the driving steam, and supplied to the steam using device or the like. The ejector 20 and the reevaporation tank 30 are connected via a suction path 40 including a main flow path 41 and a bypass path 42, and the reevaporated vapor flows through at least one of the main flow path 41 and the bypass path 42. 20 is aspirated. Since the first check valve 50 is provided in the main flow path 41 and the second check valve 60 is provided in the bypass path 42, the backflow of steam from the ejector 20 to the reevaporation tank 30 is prevented.

  After the first check valve 50 and the second check valve 60 are closed, when the pressure in the reevaporation tank 30 rises and reaches the second valve opening pressure, the second check valve 60 is first opened. Since the second opening 61A of the second check valve 60 is smaller than the first opening 51A of the first check valve 50, the flow rate of the re-evaporated steam in the bypass passage 42 is relatively small. Therefore, since the amount of re-evaporated steam in the re-evaporating tank 30 is small, a rapid pressure drop in the re-evaporating tank 30 is suppressed. Thereby, the occurrence of chattering in the second check valve 60 is suppressed.

  Thereafter, when the reevaporated vapor in the reevaporation tank 30 further increases and the pressure reaches the first valve opening pressure, the first check valve 50 is also opened. At this time, since reevaporated steam and condensate are accumulated to some extent in the reevaporation tank 30, even if the reevaporated steam is sucked all at once by opening the first check valve 50, Sudden pressure drop is alleviated. As a result, the occurrence of chattering in the first check valve 50 is suppressed.

  Further, the bypass passage 42 is provided with a needle valve 70 (regulation valve) for adjusting the flow rate of the re-evaporated steam flowing through the bypass passage 42.

  According to this configuration, the flow rate of the re-evaporated steam in the bypass passage 42 can be adjusted. When the second check valve 60 is frequently closed in an actual usage situation, the amount of re-evaporated steam can be reduced by reducing the flow rate of the bypass passage 42 with the needle valve 70. As a result, the amount of re-evaporated steam generated and the amount of suction can be balanced, and the de-evaporated steam and condensate in the re-evaporated tank 30 can be prevented from being depleted. That is, the occurrence of chattering in the second check valve 60 can be further suppressed.

  Further, the first check valve 50 has a coil spring 54 (spring) that biases the first disk valve 52 in a direction to close the first opening 51 </ b> A. The first disk valve 52 is at least due to the biasing force of the coil spring 54. The first opening 51 </ b> A is closed, the second disk valve 62 is not biased, and the second opening 61 </ b> A is closed by the weight of the second disk valve 62.

  According to this configuration, the first disk valve 52 is biased by the coil spring 54, while the second disk valve 64 is not biased by the spring or the like, so that the second valve opening smaller than the first valve opening pressure is achieved. Easy to realize pressure. Further, the first valve opening pressure and the second valve opening pressure can be adjusted by the urging force of the coil spring 54 and the weight of the second disk valve 62.

<< Other Embodiments >>
As described above, the embodiment has been described as an example of the technique disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to an embodiment in which changes, replacements, additions, omissions, and the like are appropriately performed. Moreover, it is also possible to combine each component demonstrated by the said embodiment and it can also be set as a new embodiment. In addition, among the components described in the attached drawings and detailed description, not only the components essential for solving the problem, but also the components not essential for solving the problem in order to illustrate the technology. May also be included. Therefore, it should not be immediately recognized that these non-essential components are essential as those non-essential components are described in the accompanying drawings and detailed description.

  About the said embodiment, it is good also as following structures.

  For example, the configurations of the first check valve 50 and the second check valve 60 are merely examples, and any configuration can be adopted. For example, the valve bodies of the first check valve 50 and the second check valve 60 are formed in a disk shape, but may have other shapes.

  The first check valve 50 may not have the coil spring 54. By disposing the first check valve 50 with the first opening 51A facing downward, the first disk valve 52 closes the first opening 51A by its own weight. By making the weight of the first disk valve 52 heavier than the second disk valve 62, the first valve opening pressure can be made larger than the second valve opening pressure.

  On the other hand, the second check valve 60 may have a coil spring that biases the second disk valve 62 in the closing direction. In this case, the biasing force of the coil spring is made smaller than that of the coil spring 54 of the first check valve 50. Thereby, the second valve opening pressure can be made smaller than the first valve opening pressure.

  The needle valve 70 is for adjusting the flow rate of the re-evaporated steam of the bypass valve 42 according to the actual use situation. Therefore, when the adjustment according to the actual use situation is unnecessary, the needle valve 70 is used. It may be omitted.

  As described above, the technique disclosed herein is useful for a steam supply system.

DESCRIPTION OF SYMBOLS 100 Steam supply system 20 Ejector 30 Re-evaporation tank 40 Suction path 41 Main flow path 42 Bypass path 50 1st check valve 51A 1st opening 52 1st disk valve (1st valve body)
60 Second check valve 61A Second opening 62 Second disc valve (second valve body)
70 Needle valve (control valve)

Claims (2)

A re-evaporation tank for storing condensate and re-evaporated steam;
A suction channel connected to the reevaporation tank;
An ejector that is connected to the suction path and sucks the re-evaporated vapor in the re-evaporation tank through the suction path and flows out together with the driving vapor;
The suction path includes a main flow path provided with a first check valve for preventing a reverse flow of steam from the ejector to the reevaporation tank, and a second for preventing a reverse flow of steam from the ejector to the reevaporation tank. A check valve is provided, and includes a bypass passage that bypasses the first check valve,
The first check valve includes a first opening through which steam flows and a first valve body that opens and closes the first opening, and the first valve body is configured to be the first valve at a predetermined first valve opening pressure. Configured to open the opening,
The second check valve has a second opening through which steam flows, which is smaller than the first opening, and a second valve body that opens and closes the second opening, and is smaller than the first valve opening pressure. The second valve body is configured to open the second opening at a second valve opening pressure ;
The steam supply system according to claim 1, wherein the bypass passage is provided with an adjustment valve for adjusting a flow rate of the re-evaporated steam flowing through the bypass passage . The steam supply system according to claim 1,
The first check valve has a spring that biases the first valve body in a direction to close the first opening,
The first valve body closes the first opening by at least the biasing force of the spring;
The steam supply system, wherein the second valve body is not energized, and the second opening is closed by the weight of the second valve body.

Images