JPH05770Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a differential pressure regulating device for a gas liquefaction refrigeration system equipped with an expansion turbine and a compressor.

[Prior art]

As shown in FIGS. 5 and 6, a conventional differential pressure adjustment device for a gas liquefaction refrigeration system includes impellers (not shown) of expansion turbines 2, 12, compressors 3, Thirteen impellers (not shown) are connected to each other and provided in separate gas circulation paths, that is, expansion turbine side gas circulation paths 4 and 14 and compressor side gas circulation paths 5 and 15. Due to the pressure difference between the two gas circulation paths 4, 14 and 5, 15, a thrust force is generated on the rotating shafts 1, 11, and both gas circulation paths 4, 14 and 5, 1
Gas leakage may occur from the shaft seal portion 16 that isolates the shaft seal portion 5 from the shaft seal portion 16 .

If the above-mentioned thrust force becomes excessive, it will damage the thrust bearing 6 that supports the rotating shaft.
Therefore, as shown in FIG. 5, a differential pressure adjustment device 7 consisting of a bypass path 7a and an emergency pressure relief valve 7b is provided between both gas circulation paths 4 and 5, and based on a control signal sent through a control signal line 8, In response to an increase in the differential pressure between both gas circulation paths 4 and 5 caused by an emergency shutdown due to the closure of the emergency shutoff valve 9, etc.
The emergency pressure relief valve 7b is simultaneously activated by the above control signal.
The present application relates to a structure in which excessive thrust force is prevented from acting on the rotating shaft 1 by opening the gas circulation path 5 on the compressor side and releasing the gas from the gas circulation path 5 on the compressor side to the gas circulation path 4 on the expansion turbine side. People have already proposed it (Jet No. 187904, 1982).

However, the above structure is not effective in increasing the differential pressure between the gas circulation paths 4 and 5 due to causes other than issuing a signal to open the emergency pressure relief valve 7b, such as during steady operation. Furthermore, even if an emergency signal is issued, since the emergency pressure relief valve 7b is a remotely controlled control valve, there will be a delay in response, and the differential pressure between both gas circulation paths 4 and 5 will exceed a predetermined value. Furthermore, since it is an externally powered control valve, it requires a driving source.
The structure is complex, which makes maintenance difficult and expensive.

Regarding gas leakage from the shaft seal portion 16, if the cooled gas from the expansion turbine side gas circulation path 14 leaks into the compressor side gas circulation path 15, the bearings (not shown) will freeze and the operation of the device will be interrupted. give support. Therefore, as shown in FIG.
A differential pressure control device 17 is provided, which includes a differential pressure detector 17c that detects the differential pressure through the differential pressure detector 17c, and a differential pressure control valve 17d that is controlled by the differential pressure detector 17c. When the pressure falls below a predetermined value, the control valve 17d is opened in response to a signal from the differential pressure detector 17c, and shaft seal gas is supplied from the shaft seal gas supply path 18, thereby increasing the pressure in the compressor side gas circulation path 15. method has been adopted.

However, in the above method, as with the excessive thrust force generation prevention means described above, there is a possibility that the differential pressure between both gas circulation paths 14 and 15 becomes less than a predetermined value due to a response delay of the control valve 17d. Furthermore, since it is an externally powered control valve, it requires a driving source, has a complicated structure, is difficult to maintain, and has the drawbacks of high cost.

[Purpose of invention]

The present invention has been devised in consideration of the above-mentioned problems, and is capable of constantly and reliably maintaining a predetermined differential pressure between the two gas circulation paths, does not require a driving source, has a simple structure, and is inexpensive. The object of the present invention is to provide a differential pressure adjustment device for a gas liquefaction refrigeration system that can be manufactured in the following manner.

[Structure of the idea]

In order to achieve the above object, the differential pressure regulating device for a gas liquefaction refrigeration system according to the present invention has an impeller of an expansion turbine coupled to one end of the rotating shaft and an impeller of a compressor coupled to the other end of the rotating shaft. In a differential pressure adjustment device for a gas liquefaction refrigeration system in which a turbine and a compressor are provided in separate gas circulation paths, and a predetermined pressure difference is maintained between the two gas circulation paths, a self-powered system that operates directly by the pressure difference described above is used. The two gas circulation paths can be controlled by installing a type differential pressure regulating valve between the gas circulation paths, detecting the differential pressure, and opening and closing the gas flow path using the self-powered differential pressure regulating valve having a diaphragm, etc. It is characterized in that it is constructed so that a predetermined differential pressure can be maintained at all times.

[Example 1] A first example of the present invention will be described based on FIGS. 1 and 2.

FIG. 1 is a configuration explanatory diagram showing an example of application of the present invention, in which an impeller (not shown) of an expansion turbine 22 is coupled to one end of a rotating shaft 21, and an impeller (not shown) of a compressor 23 is coupled to the other end. combined. The rotating shaft 21 is supported between the expansion turbine 22 and the compressor 23 by a thrust bearing 24 and a journal bearing 25. Expansion turbine side gas circulation path 26 where expansion turbine 22 is provided
and the exhaust port of the expansion turbine 22 in the compressor 2
A differential pressure adjustment device 2 is provided between the compressor side gas circulation path 27 provided with the
8 is provided. This differential pressure adjustment device 28 is
It consists of a self-powered differential pressure regulating valve 28a, an expansion turbine side gas circulation path pressure introduction path 28b, a compressor side gas circulation path pressure introduction path 28c, and a gas discharge path 28d.

A specific structural example of the self-powered differential pressure regulating valve 28a is shown in FIG. In FIG. 2, the upper case 31
is equipped with an expansion turbine side pressure chamber 31a and an expansion turbine side pressure introduction port 31b communicating with this expansion turbine side pressure chamber 31a, and the lower case 32 is equipped with a compressor side pressure chamber 32a and a compressor side pressure chamber communicating with this compressor side pressure chamber. A side pressure inlet 32b is provided, and both pressure chambers 31a and 32a are connected to each other by a diaphragm 33.
This diaphragm 33 is separated by
A needle valve 34 is attached to the side of the compressor side pressure chamber 32a in a protruding manner, and is biased by a pressure spring 35 provided on the opposite side of the diaphragm 33. The thrust of this pressure spring 35 is adjusted by a pressure adjustment screw 36. A sleeve 37 is attached to the lower case 32, and the sleeve 37 includes a valve seat 38 facing the needle valve 34 and a gas exhaust port 39 to which the gas exhaust passage 28d is connected.

In the above configuration, the compressor side gas circulation path 27
If the pressure in the gas circulation path 26 on the expansion turbine side is lower than the pressure in the gas circulation path 26 on the expansion turbine side, or if it is higher but the differential pressure is smaller than the pressure due to the thrust of the pressure spring 35, the needle valve 34 is pressed against the valve seat by the pressure spring 35. 38, compressor side pressure chamber 32a
Since the gas discharge port 39 and the compressor side circulation path 27 are isolated from each other, the gas in the compressor side circulation path 27 is not discharged.

However, if the pressure in the compressor side gas circulation path 27 is higher than the pressure in the expansion turbine side gas circulation path 26 and the pressure difference therebetween is greater than the pressure due to the thrust of the pressure spring 35, the diaphragm 33 moves into the expansion turbine side pressure chamber. 31a, the needle valve 34
is separated from the valve seat 38 and communicates the compressor side pressure chamber 32a with the gas exhaust port 39, so the gas exhaust path 28
Gas is released through d, and the gas circulation path 2 on the compressor side
7. Reduce the pressure.

[Embodiment 2] Another embodiment of the present invention will be described based on FIGS. 3 and 4. An impeller (not shown) of an expansion turbine 42 is coupled to one end of the rotating shaft 41, and an impeller (not shown) of a compressor 43 is coupled to the other end. The expansion turbine side gas circulation path 44 in which the expansion turbine 42 is provided and the compressor side gas circulation path 45 in which the compressor 43 is provided are separated by a shaft seal portion 46, and both gas circulation paths 44, 4 are separated from each other by a shaft seal portion 46.
A differential pressure adjustment device 48 is provided between 5 and 5. This differential pressure adjustment device 48 includes a self-powered differential pressure adjustment valve 48a, an expansion turbine side pressure introduction path 48b, a compressor side pressure introduction path 48c, and a shaft sealing gas supply path 48d. Regarding the self-powered differential pressure regulating valve 48a, the same reference numerals are used for the members having the same functions as in the first embodiment, and the explanation thereof will be omitted. The member corresponding to the needle valve 34 in the first embodiment is a spindle 54, and a steel ball 60 and a small spring 61 are enclosed in a sleeve 57.
is pressed against a valve seat 58 provided on the sleeve 57 by a small spring 61. Further, the sleeve 57 is provided with a shaft sealing gas supply port 59 to which the shaft sealing gas supply path 48d is connected.

In the above configuration, the compressor side gas circulation path 45
If the pressure of
is deflected toward the expansion turbine side pressure chamber 31a, and since the steel ball 60 is not pushed by the spindle 54, it is pressed against the valve seat 58 by the small spring 61, and the compressor side pressure chamber 32a and the shaft sealing gas supply port 59 are Therefore, the shaft seal gas is not supplied to the compressor side gas circulation path 45.

However, if the pressure in the compressor side gas circulation path 45 is lower than the pressure in the expansion turbine side gas circulation path 44,
Or, if the differential pressure is high but smaller than the pressure due to the thrust of the pressure spring 35, the diaphragm 33 is deflected toward the compressor side pressure chamber 32a, the spindle 54 pushes the steel ball 60, and this steel ball 60 pushes against the valve seat 58. Further away, the shaft seal gas supply port 59 is opened toward the compressor side pressure chamber 32a, and the shaft seal gas is supplied to increase the pressure in the compressor side gas circulation path 45.

[Effect of idea]

As described above, in the differential pressure regulating device for a gas liquefaction refrigeration system according to the present invention, the impeller of the expansion turbine is coupled to one end of the rotating shaft, and the impeller of the compressor is coupled to the other end, and the impeller of the expansion turbine and the compressor are coupled to one end of the rotating shaft. and are provided in separate gas circulation paths, and in a differential pressure adjustment device for a gas liquefaction refrigeration system that maintains a predetermined differential pressure between both gas circulation paths, a self-powered differential pressure adjustment device that operates directly by the above-mentioned differential pressure. A valve is provided between the gas circulation paths. This allows the two gas circulation paths to always be maintained at a predetermined differential pressure, and
Since no driving source is required, the structure is simple, maintenance is easy, and manufacturing costs can be reduced.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention,
Fig. 1 is a configuration explanatory diagram showing an example of application of the present invention;
The figure is a vertical sectional view showing an example of the structure of the self-powered differential pressure regulating valve used in the above embodiment, FIGS. 3 and 4 show other embodiments of the present invention, and FIG. 3 shows an application example. FIG. 4 is a vertical sectional view showing a structural example of a self-powered differential pressure regulating valve, FIG. 5 is a structural explanatory drawing showing a conventional example, and FIG. 6 is a structural explanatory drawing showing another conventional example. . 21, 41 are rotating shafts, 22, 42 are expansion turbines, 23, 43 are compressors, 26, 44 are expansion turbine side gas circulation paths, 27, 45 are compressor side gas circulation paths, 28, 48 are differential pressure adjustment device, 28a, 48
a is a self-powered differential pressure regulating valve.

Claims (1)

[Scope of utility model registration request] An impeller of an expansion turbine is connected to one end of the rotating shaft, and an impeller of a compressor is connected to the other end, and the expansion turbine and compressor are provided in separate gas circulation paths, and a In the differential pressure adjustment device for gas liquefaction refrigeration equipment that maintains a predetermined differential pressure,
A differential pressure regulating device for a gas liquefaction refrigeration system, characterized in that a self-powered differential pressure regulating valve that is directly operated by the differential pressure is provided between the gas circulation path.