JP3787078B2 - Unstable operating area sensing device for turbo compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sensing device for quickly and easily sensing a rotating stall and a surge that frequently occur during operation of a turbo compressor.
[0002]
[Prior art]
In general, in a turbo type compressor, the working flow rate of the working fluid gradually decreases, and when the flow rate is below a predetermined flow rate, a rotating stall and a surge are generated. These occurrences can degrade the performance of the compressor system and in the worst case can cause catastrophic mechanical damage to the compressor system. Therefore, it is most important to detect the turning stall and the occurrence of a surge quickly and accurately and eliminate them.
[0003]
Conventionally, a sensing device including a high-frequency pressure sensor or a vibration sensor and a signal analysis system is used to detect the rotation stall and the surge region. However, since these sensors are expensive, the manufacturing cost of the sensing device increases. In addition, the operation of the signal analysis system requires advanced techniques, and the maintenance and maintenance of the system is expensive. In order to overcome these problems, there is a need for a novel turbo compressor type sensing device and sensing method that is simple, reliable, reliable, and economical in structure, operation, maintenance, and maintenance. Yes.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to replace a conventional sensing device using an expensive high-frequency pressure sensor or vibration sensor and a complicated analysis system, with a simple configuration and operation, low manufacturing cost, maintenance and management costs, and reliability. It is an object of the present invention to provide a highly novel turbo-type compressor unstable operation region sensing device.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems, an unstable operation region sensing device for a turbo compressor according to the present invention includes a sensor body, and a first pressure pipe and a second pressure pipe penetrating the sensor body. A first pressure extraction hole and a second pressure extraction hole formed at the end of the same side of both pressure pipes and opened at one flat end surface of the sensor body at a predetermined interval, and on the flat end surface of the sensor body An unstable operation area sensor having a dividing film provided across both extraction holes, and the unstable operation area sensor is connected to a turbocharger so that the longitudinal direction of the division film is parallel to the rotation axis of the impeller. The first and second pressure extraction holes are provided on the inlet side of the impeller in the mold compressor or in the diffuser on the outlet side of the impeller so that the longitudinal direction of the divided membrane is parallel to the flow direction of the fluid flowing out of the impeller The turbo compressor becomes unstable due to the pressure difference between Configured to detect whether or not the operation in the region.
[0006]
It is desirable to connect a pressure sensor to a monitor that monitors the pressure between the first and second pressure outlet holes to detect the stability and instability of the turbo compressor.
[0007]
When the pressure difference between the first and second pressure outlet holes indicates that the turbo compressor is operating in an unstable operation region, warning means for immediately warning the driver of the turbo compressor is provided. It is desirable to connect to a sensor.
[0008]
The sensor 20 is provided in a diffuser on the inlet side of the impeller or on the outlet side of the impeller . In any case, when the turbo compressor is operating in the stable operation region, the flow direction of the working fluid entering the inlet side of the impeller substantially coincides with the longitudinal direction of the divided membrane. There is no pressure difference between the second pressure extraction holes. On the other hand, when a rotating stall or surge occurs and the turbo compressor is operating in an unstable operation region, the flow direction of the working fluid does not coincide with the longitudinal direction of the divided membrane. A pressure difference is generated between the two pressure extraction holes. When this pressure difference is directly connected to the U pipe or converted into an electrical signal and displayed on the monitor, it is possible to recognize that this pressure difference has occurred and the turbo compressor is operating in an unstable operation region. The driver can be warned by a monitor, display, lamp or buzzer.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an unstable operation region sensing device for a turbo compressor according to the present invention will be described in detail with reference to the drawings.
[0010]
1 and 2 are a front view and a side view, respectively, of an embodiment of an unstable operation region sensing device for a turbo compressor according to the present invention.
[0011]
The turbo-type compressor unstable operation region sensor 20 (hereinafter simply referred to as the sensor 20) is provided in the turbo-type compressor 7 as shown in the longitudinal sectional view of FIG. 3 and the transverse sectional view of FIG. . The turbo compressor 7 (hereinafter simply referred to as the compressor 7) includes an impeller 12, a diffuser 14 on the outlet side thereof, a suction pipe 8 at the inlet of the compressor 7, and a volute 31 having an outlet 30. The diffuser 14 is located on the outlet side of the impeller 12 and continues to the outlet 30. The sensor 20 is disposed at the inlet of the impeller 12 in the suction pipe 8. The working fluid is introduced into the compressor 7 from the suction pipe 8, enters the diffuser 14 rotates the impeller 1 2, and is discharged from the outlet 30 of volute 31. At this time, the sensor 20 detects the pressure difference according to the flow direction of the working fluid.
[0012]
As shown in FIGS. 1 and 2, the sensor 20 includes a sensor body 22, a first pressure pipe 25, a second pressure pipe 26 that penetrates the sensor body 22 in the axial direction, and a sensing gas 22. A first pressure extraction hole 25a and a second pressure extraction hole 26a forming one end of the first and second pressure pipes 25 and 26, which are opened at a predetermined interval on the flat surface (flat end surface) of the tip; A dividing film 28 is provided across the pressure take-out holes 25a and 26a.
[0013]
The other ends of the first and second pressure pipes 25 and 26 are connected to a pressure sensor or a U-shaped pressure pipe (not shown), and the pressure generated in the pressure take-out holes 25a and 26a is an electrical signal or a visual signal. It can be displayed as.
[0014]
3 and 4, the working fluid of the impeller 12 in the suction pipe 8 of the compressor 7 is arranged so that the longitudinal direction of the dividing film 28 is parallel to the axial direction of the impeller 12, as shown in FIGS. Arranged on the inlet side.
[0015]
The flow rate (output speed) of the working fluid at the outlet 30 of the compressor 7 is variously set and the sensor 20 is rotated in the direction indicated by the arrow A in FIG. 4 to create a sensor rotation angle-standard pressure difference characteristic curve. did. This characteristic curve is shown in FIG. There are four output speeds of 13 m / s, 29 m / s, 48 m / s, and 81 m / s, and the rotation angle of the sensor 20 in the direction of arrow A is −180 ° to 180 °. The standard pressure difference is (P1-P2) / (Pt-Ps) (where P1 is the pressure of the first pressure extraction hole 25a, P2 is the pressure of the second pressure extraction hole 26a, Pt is the total pressure, Ps Is a static pressure) and is a dimensionless value.
[0016]
As is apparent from FIG. 5, the characteristic curves of the respective output speeds have the same shape, and the standard pressure differences are substantially equal at the same rotation angle. That is, the sensor rotation angle-standard pressure difference characteristic indicates a characteristic dependent on the sensor rotation angle regardless of the output speed. Accordingly, the sensor 20 can be used for the compressor 7 irrespective of the capacity / size of the compressor and the rotational speed of the impeller.
[0017]
FIG. 6 is a characteristic curve of the flow coefficient-static pressure increase coefficient of the compressor 7. When the flow coefficient is 1.3 or less, the compressor 7 is operated in the unstable operation region 10 and exceeds 1.3. The compressor 7 operates in the stable operating area 9. Here, the flow rate coefficient and the flow rate / (Paix impeller diameter x impeller output width x impeller speed), also the static pressure rise coefficient is defined as the pressure difference / {fluid density x (impeller speed) ^2/2} . In the drawing, A, B, and C show examples of operating points in the stable operating region 9 of the compressor 7, and D and E show examples of operating points in the unstable operating region 10 of the compressor 7.
[0018]
FIG. 7A shows the sensor rotation angle-standard pressure difference characteristic when the compressor 7 operates at operating points A, B, and C within the stable operating region 9. Also in this characteristic diagram, as long as the operating point is within the stable operating region 9, it changes in a sine curve shape corresponding to the rotation angle of the sensor 20 regardless of the operating point. That is, as is clear from FIG. 7 (A), when the rotation angle of the sensing unit 20 is 0 °, the standard pressure difference is substantially zero. This means that when the rotation angle of the sensor 20 is 0 °, the pressure difference between the first and second pressure extraction holes 25a and 25b is substantially zero. As shown in FIG. 7B , this is because the working fluid flows in parallel to the divided film 28 set parallel to the rotation axis of the impeller 12, and therefore the first and second pressure extraction holes 25a and 25b. This is because no pressure difference occurs between them. As is clear from this, when the rotation angle of the sensor 20 is 0 ° and the standard pressure difference is 0, the compressor 7 is operating normally in the stable operation region 9.
[0019]
FIG. 8A shows the sensor rotation angle-standard pressure difference characteristic when the compressor 7 operates at the operating points D and E in the unstable operating region 10. Also in this characteristic diagram, when the operating point is in the unstable operating region 10, the operating point substantially changes regardless of the operating point and changes in a cosine curve shape corresponding to the rotation angle of the sensor 20. That is, as apparent from FIG. 8A, when the rotation angle of the sensor 20 is 0 °, the standard pressure difference is maximized. This means that the pressure difference between the first and second pressure extraction holes 25a and 25b is substantially maximized when the rotation angle of the sensor 20 is 0 °. As shown in FIG. 8B, this is because the working fluid flows substantially perpendicularly into the dividing film 28 set parallel to the rotation axis of the impeller 12, so that the first and second pressure extraction holes are formed. This is because the maximum pressure difference occurs between 25a and 25b. As is clear from this, when the rotation angle of the sensor 20 is 0 °, when the standard pressure difference is maximized, the compressor 7 is operated in the unstable operation region 10. It is indicated that a turning stall or a surge is generated.
[0020]
The sensor 20 is set so that its rotation angle is 0 °, and a U-tube for pressure measurement or other appropriate pressure measuring device is connected to the first and second pressure pipes 25 and 26 of the sensor 20. Then, the pressures in the first and second pressure extraction holes 25a and 26a are processed electronically or theoretically, and these pressure differences are displayed electronically or visually on a monitor or display. When the standard pressure difference is at or near the maximum value in FIG. 8A, it indicates that the compressor 7 is unstable, so the compressor 7 is returned to the normal state. In this way, it is possible to avoid the occurrence of turning stall and surge.
[0021]
When the pressure difference between the first and second pressure extraction holes 25a, 26a is displayed on the monitor or on the display, or when the operation state of the compressor 7 is in the unstable operation region 10, a lamp as a warning means is lit. Or buzzer sounds. Thus, it is possible to detect whether the current operating state of the compressor is operating in the stable operation region or in the unstable operation region.
[0022]
FIGS. 9 and 10 show a longitudinal sectional view and a transverse sectional view, respectively, of an embodiment in which the sensor 20 is provided in the diffuser 14 on the outlet side of the impeller 12. The sensor 20 is arranged so that the longitudinal direction of the dividing film 28 is parallel to the flow direction of the working fluid flowing out of the impeller 12, and the rotation angle of the sensor 20 in this state is set to 0 °. This embodiment also shows a characteristic diagram equivalent to the characteristic diagrams of FIGS. 5, 7 (A) and 8 (A), and the same operation as the embodiment of FIGS. 3 and 4 is achieved.
[0023]
【The invention's effect】
The unstable operation region sensing device for a turbo compressor according to the present invention has the advantage that the structure is extremely simple and the manufacture is inexpensive and easy. In addition, since this sensing device is not a complicated and expensive electric device and electronic device, it is easy to maintain, inspect, and handle, so that there is an effect that a large cost is not required and reliability is high. Furthermore, the sensing device of the present invention can be used for any compressor regardless of the capacity and size of the compressor and the rotational speed of the impeller, and the compressor is in the stable operating range with the same characteristics. There is also an effect that it can be detected whether it is in the operating region. In addition, when a compressor becomes unstable using a monitor or display, or using a warning means such as a lamp or buzzer, quickly detect this and reset the compressor to a stable state. It is possible to prevent deterioration of the compressor performance and to prevent the compressor system from fatal mechanical damage.
[Brief description of the drawings]
FIG. 1 is a front view of an embodiment of an unstable operation region sensing device for a turbo compressor according to the present invention.
FIG. 2 is a side view of the sensing device of FIG.
FIG. 3 is a longitudinal sectional view of a turbo compressor in which the sensing device of FIG. 1 is mounted on the inlet side of a working fluid.
4 is a cross-sectional view of the compressor of FIG.
FIG. 5 is a sensor rotation angle-standard pressure difference characteristic curve diagram of a sensing device for each fluid velocity of a working fluid.
FIG. 6 is a diagram showing a stable operation region and an unstable operation region of a compressor in a flow coefficient-static pressure increase coefficient characteristic diagram.
7A is a sensor rotation angle-standard pressure difference characteristic curve diagram of the sensing device in the stable operation region of the compressor, and FIG. 7B is a rotation angle of the sensor in the stable operation region of the compressor. It is a figure which shows the arrangement | positioning relationship with respect to the impeller of a sensor when making is 0 degree.
8A is a sensor rotation angle-standard pressure difference characteristic curve diagram of the sensing device in the unstable operation region of the compressor, and FIG. 8B is a sensor curve of the sensor in the unstable operation region of the compressor. It is a figure which shows the arrangement | positioning relationship with respect to the impeller of a sensor when a rotation angle is 0 degree.
FIG. 9 is a longitudinal sectional view of an embodiment of a turbo compressor in which the sensing device of FIG. 1 is mounted on the outlet side of a working fluid.
10 is a cross-sectional view of the compressor of FIG.
[Explanation of symbols]
7 Turbo type compressor 8 Suction pipe 9 Stable operation area 10 Unstable operation area 12 Impeller 14 Diffuser 20 Sensor 22 Sensor body 25 First pressure pipe 25a First pressure extraction hole 26 Second pressure pipe 26a Second Pressure extraction hole 28 Dividing membrane 30 Outlet 31 volute

Claims (3)

In the unstable operation region sensing device for a turbo compressor (7) having an impeller (12) and a diffuser (14) on the outlet side,
A sensing body (22);
A first pressure pipe (25) and a second pressure pipe (26) penetrating the sensor body (22);
A first pressure extraction hole (25a) formed at the same end of both pressure pipes (25, 26) and opened at a flat end surface of the sensor body (22) at a predetermined interval, and a second pressure extraction A hole (26a);
An unstable operation area sensor (20) having a dividing film (28) provided across the two extraction holes (25a, 26a) on the flat end surface of the sensor body (22),
The sensor (20) is placed on the inlet side of the impeller (12) in the turbo compressor (7) so that the longitudinal direction of the dividing membrane (28) is parallel to the rotation axis of the impeller (12). Or in the diffuser (14) on the outlet side of the impeller (12) so that the longitudinal direction of the divided membrane (28) is parallel to the flow direction of the fluid flowing out of the impeller (12), And a pressure difference between the second pressure extraction holes (25a, 26a) and detecting whether or not the turbo compressor (7) is operating in the unstable operation region (10). An unstable operating area sensing device for a compressor. A monitor for monitoring the pressure between the first and second pressure outlet holes (25a, 26a) and detecting the stability and instability of the turbo compressor is connected to the pressure sensor (20). The unstable operation region sensing device for a turbo compressor according to claim 1. If the pressure difference between the first and second pressure extraction holes (25a, 26a) indicates that the turbo compressor (7) is operating in an unstable operating region, this is immediately indicated to the driver. 3. An unstable operating region sensing device for a turbo compressor according to claim 1, wherein a warning means for warning is connected to the pressure sensor (20).

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