JP2008150995A - Steam ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily installable and inexpensive steam ejector without requiring electricity and a high pressure air source. <P>SOLUTION: Suction chambers 17 and 18 of the steam ejectors 2 and 4 are connected to a steam pipe 8 via a pressure reducing valve 1. A re-evaporation tank 13 and the suction chambers 17 and 18 are connected by a suction passage 12. A three-way switching valve 26 is interposed between the suction passage 12 and the suction chamber 17. An outlet pipe 11 is connected to diffusers 19 and 20 of the ejectors 2 and 4. The right end of a pipe 5 is connected to the middle of the outlet pipe 11, and the other end is connected to a secondary side pressure detecting port 3 of the pressure reducing valve 1. Steam pressure detected in the pipe 5 is maintained under predetermined constant pressure by the pressure reducing valve 1 as a self-actuated pressure regulating valve, and since a driving source such as electricity and high pressure air is not required, the inexpensive and simple steam ejector can be provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a steam ejector that ejects drive steam from a nozzle at high speed and generates suction force in a suction chamber by velocity energy of the fluid.

  The steam ejector is connected to a pressure control valve on the inlet side of a suction chamber with a built-in nozzle, and a pressure sensor is attached to the outlet side of the diffuser, and the valve opening of the pressure control valve is driven according to the detected value of this pressure sensor. By controlling, the suction force generated in the suction chamber can be controlled.

This steam ejector requires an electric circuit that electrically connects the pressure sensor and the pressure control valve, and electricity and a high-pressure air source for driving the pressure control valve as the other force type pressure control valve. In addition, the ejector device itself becomes expensive, and there is a problem that much labor and cost are required for installation of the device.
JP 2003-269400 A

  The problem to be solved is to provide a steam ejector that does not require electricity, a high-pressure air source, or the like, is easy to install, and is inexpensive.

  The present invention comprises a nozzle part composed of pores for restricting fluid, a suction chamber formed around the nozzle part, and a diffuser communicating with the suction chamber and the nozzle part. Connect the pressure reducing valve, connect the secondary pressure detection port of the pressure reducing valve to the outlet side of the diffuser or the outlet side of the diffuser, connect the suction chamber to the reevaporation tank, and At least two ejectors are arranged, a switching valve for the flow path is attached to the inlet side of the suction chamber of the steam ejector or the outlet side of the diffuser, and the connection position of at least two steam ejectors by switching operation of the switching valve Are switched to a parallel state or a serial state.

  In the steam ejector of the present invention, the pressure reducing valve is connected to the inlet side of the nozzle portion, and the secondary pressure detection port of the pressure reducing valve is connected to the outlet side portion in the diffuser or the outlet side portion of the diffuser. Therefore, the pressure reducing valve is a self-acting pressure regulating valve, which does not require electricity or high-pressure air as a driving source, does not require a pressure sensor, and can be an inexpensive and simple steam ejector.

  Further, according to the present invention, at least two steam ejectors and a flow path switching valve are attached, and the switching positions of the switching valves are switched to switch the connection position of at least two steam ejectors to a parallel state or a serial state. Re-evaporated steam that varies from a small amount to a large amount can be achieved by placing the steam ejector in parallel when a large amount of intake steam is generated, and by connecting the steam ejector in series when the amount of intake steam is small. Can be inhaled quickly.

  The present invention uses a pressure reducing valve as a self-acting pressure regulating valve. As this pressure reducing valve, a pressure reducing member such as a diaphragm, a bellows, or a piston is provided on a surface of a secondary side pressure detecting port. When the secondary pressure is applied and a predetermined elastic force such as a coil spring is applied to the other surface of the pressure-sensitive member and the secondary pressure of the pressure reducing valve is lower than the predetermined elastic force of the coil spring, the main valve of the pressure reducing valve opens. Then, it is preferable that the pressure on the secondary side of the pressure reducing valve can be maintained at a predetermined value by causing the high pressure steam on the primary side of the pressure reducing valve to flow down to the secondary side.

  In FIG. 1, a pipe line 5 that connects the pressure reducing valve 1, the two steam ejectors 2, 4, the outlet side portions of the two steam ejectors 2, 4 and the secondary pressure detection port 3 of the pressure reducing valve 1. A vapor ejector is constituted by the re-evaporation tank 13.

  The pressure reducing valve 1 is a pressure reducing valve as a self-acting pressure adjusting valve, and the pressure on the outlet side of the steam ejectors 2 and 4 is applied to the secondary side pressure detecting port 3 from the pipe line 5, and a pressure sensing such as a diaphragm (not shown). By applying the pressure to one surface of the member, the outlet side pressure of the steam ejectors 2 and 4 can be maintained at a predetermined value.

  A steam pipe 8 communicating with a high-pressure steam source is connected to the inlet side of the pressure reducing valve 1, and a gas-liquid separator 6 and a steam trap 7 are integrally provided below the pressure reducing valve 1. In the gas-liquid separator 6, the condensate as a liquid mixed in the steam flowing into the pressure reducing valve 1 from the steam pipe 8 is separated from the steam, and further the condensate separated by the steam trap 7. Can be discharged outside the system. A communication pipe 10 with a check valve 9 interposed is connected to the lower part of the steam trap 7.

  The steam ejectors 2 and 4 are constituted by suction chambers 17 and 18 having a nozzle portion and diffusers 19 and 20, respectively. In the present embodiment, an example is shown in which the right end of the pipe line 5 is connected to a position away from the diffusers 19 and 20 of the steam ejectors 2 and 4, but the right end of the pipe line 5 does not leave the diffusers 19 and 20. It can also be connected to the outlet side in 19,20. The right end of the pipe 5 is preferably connected to a position where the process steam pressure supplied from the outlet pipe 11 to a not-shown steam using device or the like can be detected. At the lower ends of the suction chambers 17 and 18, a suction passage 12 into which the fluid sucked in the suction chambers 17 and 18 flows is provided.

The lower end of the suction passage 12 is connected to the reevaporation tank 13. A three-way switching valve 26 is interposed between the suction passage 12 and the suction chamber 17. The outlet side of the steam ejector 4 communicates with the three-way switching valve 26 and the branched two-way switching valve 27 and check valve 28.

The steam ejectors 2 and 4 generate a predetermined suction force in the suction chambers 17 and 18 by the high-pressure steam supplied from the steam pipe 8, and suck the steam re-evaporated from the condensate in the re-evaporation tank 13. It is possible to suck from the passage 12.

 The re-evaporation tank 13 has a vertically long cylindrical shape, and a high-temperature condensate inflow pipe 14 is connected to the central portion on the left side and a condensate discharge pipe 15 is connected to the lower side of the right side. A steam trap 16 is interposed in the condensate discharge pipe 15. Further, the lower end of the communication pipe 10 attached to the lower part of the steam trap 7 of the pressure reducing valve 1 is connected to the upper part of the reevaporation tank 13.

  Inside the reevaporation tank 13, the high-temperature condensate flowing in from the high-temperature condensate inflow pipe 14 is re-evaporated and becomes steam again, and is sucked from the suction passage 12 into the suction chambers 17 and 18 of the ejectors 2 and 4. Condensate whose temperature has decreased to some extent after re-evaporation passes through the steam trap 16 and is discharged from the condensate discharge pipe 15 to the outside of the system.

  The high-pressure steam supplied from the steam pipe 8 is decompressed to a predetermined pressure by the pressure reducing valve 1 and supplied to the nozzle part built in the suction chambers 17 and 18 of the ejectors 2 and 4, and the driving steam is throttled by this nozzle part. As a result of the high-speed flow, a suction force is generated and the re-evaporated vapor is sucked from the suction passage 12. The sucked re-evaporated steam is mixed with the driving steam and supplied to the steam using device or the like from the outlet pipe 11 through the diffusers 19 and 20.

  When the amount of re-evaporated steam sucked from the suction passage 12 of the steam ejectors 2 and 4 is large, the two-way switching valve 27 is opened and the three-way switching valve 26 is operated to connect the suction passage 12 and the suction chamber 17. By doing so, the connection positions of the two steam ejectors 2 and 4 are in a parallel state, and a large amount of re-evaporated steam can be sucked through the suction passage 12 by both of the steam ejectors 2 and 4.

When the amount of re-evaporated steam sucked from the suction passage 12 is small, the two-way switching valve 27 is closed and the three-way switching valve 26 is operated to connect the outlet side of the steam ejector 4 and the suction chamber 17 of the steam ejector 2. By connecting, the connection positions of the two steam ejectors 2 and 4 are in series, and the steam sucked from the suction passage 12 into the suction chamber 18 of the steam ejector 4 passes through the three-way switching valve 26 and the other steam ejector 2. Are sucked into the suction chamber 17 and discharged to the downstream side of the outlet pipe 11.

  The vapor pressure passing through the outlet pipe 11 is transmitted to the secondary side pressure detection port 3 of the pressure reducing valve 1 through the pipe line 5, thereby being equal to the set pressure set by the coil spring or the like of the pressure reducing valve 1. Maintained.

  By providing the gas-liquid separator 6 and the steam trap 7 at the lower part of the pressure reducing valve 1, the condensate is mixed into the steam supplied to the nozzle portions built in the suction chambers 17 and 18 of the steam ejectors 2 and 4. It is a steam with high dryness, and the suction force in the suction chambers 17 and 18 of the ejectors 2 and 4 can be maintained at the highest level.

  The high-temperature condensate separated by the gas-liquid separator 6 below the pressure reducing valve 1 flows down from the steam trap 7 to the re-evaporation tank 13 and re-evaporates, and is sucked into the suction chambers 17 and 18 of the ejectors 2 and 4. As a result, the stored thermal energy can be effectively recovered.

The block diagram which shows the Example of the steam ejector of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressure reducing valve 2 Steam ejector 3 Secondary side pressure detection port 4 Steam ejector 5 Pipe line 6 Gas-liquid separator 7 Steam trap 8 Steam pipe 11 Outlet pipe 12 Suction passage 13 Re-evaporation tank 14 High temperature condensate inflow pipe 15 Condensate discharge pipe 16 Steam traps 17 and 18 Suction chambers 19 and 20 Diffuser 26 Three-way switching valve 27 Two-way switching valve

Claims (1)

A pressure reducing valve is connected to the inlet side of the nozzle part in a nozzle part composed of a fine hole for restricting fluid, a suction chamber formed around the nozzle part, and a diffuser communicating with the suction chamber and the nozzle part. Then, the secondary pressure detection port of the pressure reducing valve is connected to the outlet side part in the diffuser or the outlet side part of the diffuser, the suction chamber is connected to the re-evaporation tank, and the steam ejector is connected to at least 2 Place a stand and install a flow path switching valve on the inlet side of the suction chamber of the steam ejector or on the outlet side of the diffuser. Or the steam ejector characterized by switching to a serial state.

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