JP2002317791A - Reverse rotation detecting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reverse rotation detecting system for foreseeing an indication of the reverse rotation in an early stage to stop the rotation. SOLUTION: A turbine type drive unit 21 and a compressor 4 are connected to each other through a rotor 3 to form a compressor 1. When starting and stopping the compressor 1, a turning device 5 operates the low-speed rotation. When operating the low-speed rotation, pressure in an inlet and an outlet of the compressor 4 is taken into a computing unit 13 by pressure detecting units Ps and Pd, and when a pressure difference between them is larger than the predetermined value, a detecting signal A is output as an indication of the generation of the reverse rotation. An over current detecting unit 10 detects the over current of a turning motor 6, and outputs the signal B. When both the signals A and B are input to an AND element 14, the AND element 14 outputs the reverse rotation foreseeing signal 21 to a control unit 15, and the control unit 15 turns the motor 6 off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for detecting reverse rotation of a rotary machine such as a compressor, and predicts reverse rotation of a rotor at an earlier stage to ensure that a turning device that performs low-speed rotation is damaged by reverse rotation. It is a system to prevent.

[0002]

2. Description of the Related Art In a compressor train or the like, a low-speed rotation is usually performed by a turning device connected to a rotor at the time of starting or after stopping to avoid distortion of the rotor. During such a low-speed rotation operation, the reverse rotation of the rotor may occur, and the reverse rotation of the rotor leads to breakage of the turning device. To prevent this, it is necessary to detect this behavior at an early stage when the rotor is likely to reversely rotate, and to disconnect the turning device from the drive system.

FIG. 4 shows a reverse rotation detecting method for this purpose.
6 is a configuration example of a detection unit generally used in the related art. The detecting means includes a vertical groove 31 formed in the rotor 30, two pulse transmitting means 32, 33 facing the outer surface of the rotor at intervals in the circumferential direction, and a control unit connected to the pulse transmitting means 32, 33. 34. 35 is a control unit
The motor 35 of the turning device, which is controlled "ON" and "OFF" by the arrow, the arrow 36 indicates the forward rotation direction of the rotor,
Reference numeral 7 denotes a reverse rotation direction of the rotor.

In the above configuration, when the rotor 30 rotates forward 36, pulse signals are input to the control unit 34 from the two pulse transmitting means in the order of 32 → 33. In addition, reverse rotation 3
At 7 o'clock, the pulse signal is output from the control unit 34 in the reverse order of 33 → 32.
Is input to When the control unit 34 detects the signal of 33 → 32 at the time of reverse rotation 37, it controls the motor 35 of the turning device to “OFF” in conjunction with the detection.

[0005]

However, in the above-described conventional method, since the reverse rotation of the rotor is detected in the state where the rotor has started to rotate in the reverse direction, there is a danger that the turning device may be damaged at this point, and There is a problem that the effect of preventing damage is not obtained. Also, two pulse transmitting means 32, 33
However, there is a problem that the cost increases because the dedicated control unit 34 is required.

In view of the above-mentioned conventional situation, the present invention predicts the reverse rotation of the rotor at an earlier stage and sets the drive of the rotor to "OFF" at a low speed rotation by the turning operation of the rotating machine. It is an object of the present invention to provide an inexpensive reverse rotation detection system capable of reliably preventing the turning device from being damaged.

[0007]

The present invention provides the following means for solving the above-mentioned problems.

(1) An inlet pressure detector and an outlet pressure detector for detecting the pressures at the inlet and the outlet of the compressor, and both pressure signals of the inlet and outlet pressure detectors are taken to obtain a difference between the two pressure signals. When the pressure difference is equal to or greater than a predetermined value, a calculation unit that outputs a first sign signal by regarding the sign as the occurrence of reverse rotation and detects an overcurrent state of the motor that performs the turning operation of the compressor, and detects the sign of reverse rotation. An overcurrent detector that outputs a deemed second sign signal, an AND element that inputs the first and second sign signals, and outputs a reverse rotation prediction signal when both signals are input, A control unit for stopping a motor that performs the turning operation by a signal.

(2) An inlet pressure detector and an outlet pressure detector for detecting the pressures at the inlet and the outlet of the compressor, and both pressure signals of the inlet and outlet pressure detectors are taken in, and the difference between the two pressure signals is obtained. When the pressure difference becomes equal to or more than a predetermined value, a calculation unit that outputs a reverse rotation prediction signal assuming that it is a sign of occurrence of reverse rotation, and control to stop the motor that performs the turning operation of the compressor based on the reverse rotation prediction signal from the calculation unit A reverse rotation detection system, comprising:

(3) The first sign signal from the arithmetic unit and the second sign signal from the overcurrent detector are respectively output to the AND element and are also output to the OR element in parallel. The control unit captures a reverse rotation prediction signal from the AND element and a reverse rotation prediction signal from the OR element,
The reverse rotation detection system according to claim 1, wherein the motor that performs the turning operation is stopped by at least one of the two signals.

In (1) of the present invention, the fluid pressure difference between the inlet and the outlet of the compressor is monitored by the pressure detector and the arithmetic unit during low-speed rotation when the compressor is started or stopped. The fluid pressure difference between the compressor inlet and the outlet that occurs during rotation is determined, and a first sign signal is sent to the AND element as an indication of the reverse rotation of the rotor at an initial stage when the pressure difference rises. The rise in the fluid pressure difference between the inlet and the outlet of the compressor is simultaneously applied to the motor of the turning device as a load increase,
An overcurrent condition is generated, and a second indication signal is sent from the overcurrent detector to the AND element as an abnormality occurrence signal. AND
The element transmits the reverse rotation prediction signal to the control unit only by inputting the two symptom signals, and the control unit performs an operation of stopping the motor of the turning device.

In (1) of the present invention, since both the first and second sign signals are signs including the sign that the reverse rotation of the rotor starts, the reverse rotation is predicted before the reverse rotation of the rotor occurs. It is possible to turn off the motor of the turning device in advance and to surely prevent the turning device and its motor from being damaged due to the actual reverse rotation of the rotor. Also, no special instrument is required for reverse rotation detection, simple operation unit, existing overcurrent detector, pressure detector, AND
Since a device generally used in a plant, such as an element, can be used, a system can be configured at low cost.

In (2) of the present invention, only the reverse rotation sign signal obtained by the arithmetic unit is used as the reverse rotation prediction signal, and the overcurrent detector and the AND element are not required. Simplifies the system configuration,
An inexpensive and easy-to-use system can be provided. The overcurrent signal used in the invention (1) is detected including the occurrence of overcurrent due to other factors. On the other hand, since the sign signal detected by the arithmetic unit directly extracts the sign of the reverse rotation of the rotor, it is greatly related to the prediction of the reverse rotation. In (2) of the present invention, since the control is performed only by the sign signal from the calculation unit, the system is simplified as described above.

In (3) of the present invention, the first sign signal from the arithmetic unit and the second sign signal from the overcurrent detector are output to an AND element and an OR element, respectively.
According to this system, the motor of the turning device is controlled to be turned "OFF" by one or both of the reverse rotation prediction signals obtained from the D element and the OR element. At the same time, abnormalities of the turning device and the motor due to other factors can be detected.

[0015]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a block diagram of a reverse rotation detection system according to the first embodiment of the present invention. In the figure, reference numeral 1 denotes a compressor, which is composed of a turbine type drive unit 2 and a compressor unit 4 connected to the turbine type drive unit 2 by a rotor 3. 5 is a turning device for starting provided on the rotor 3, 6 is a drive motor of the turning device, and 7 is a clutch on the rotor 3.

The reverse rotation detection system 20 for the rotor 3 includes an overcurrent detector 10 connected to the motor 6 of the turning device 5 and a pressure detector provided at the inlet 11 and the outlet 12 of the compressor unit 4. An operation unit 13 that calculates a reverse rotation sign based on the difference between Ps and Pd and the detected pressures of the pressure detectors Ps and Pd and outputs a reverse rotation sign signal A;
An AND element 14 and an AND element 1 that input both the detection signal B of 0 and the output signal A of the operation unit 13 and output the reverse rotation prediction signal 21 only when both the signals A and B are input
And a control unit 15 for turning off the switch of the motor 6 of the turning device 5 by an output signal from the control unit 4.

The overcurrent detector 10 is generally used to detect an overcurrent state caused by a large load applied to the motor 6 due to a failure of the rotating device or the like, to stop the operation and to protect the motor 6. Here, it is used as an element for predicting the reverse rotation of the rotor, and outputs an abnormality occurrence signal B when an overcurrent state occurs.

In the above configuration, if the rotor 3 is rotating forward during the low-speed rotation after the compressor 1 is started and stopped, the pressure detector Ps at the inlet of the compressor unit 4 and the pressure detector at the outlet are provided. The pressure difference from Pd changes within a substantially constant range. When reverse rotation of the compressor 1 occurs,
The pressure of the compressor inlet pressure detector Ps is equal to the outlet pressure detector Pd
Rises above the pressure.

The arithmetic unit 13 takes in the pressure signals of the pressure detectors Ps and Pd at the compressor inlet and outlet at the time of the low-speed rotation operation, and sets an initial sign value of an abnormal start of the pressure difference as a comparison coefficient k in advance. The pressure difference is compared and calculated according to an equation, Ps−Pd ≧ k, and the reverse rotation sign signal A is output when the pressure difference is equal to or larger than the k value.

In the system having the above-described configuration, when the compressor 1 starts or stops at a low speed, the fluid pressure difference between the inlet and the outlet of the compressor unit 4 determines the pressure signals of the pressure detectors Ps and Pd. Is monitored by the arithmetic unit 1
In 3, when an increase in the fluid pressure difference between the inlet and the outlet of the compressor section 4 that occurs when the rotor 3 rotates in the reverse direction is detected, the signal is sent to the AND element 14 as a reverse rotation sign signal A of the rotor 3 in the initial stage.

The above-mentioned increase in the fluid pressure difference between the inlet and the outlet of the compressor unit 4 simultaneously applies a load increase to the motor 6 of the turning device 5 and causes an overcurrent state exceeding a predetermined current upper limit. It is sent from the overcurrent detector 10 to the AND element 14 as the abnormality occurrence signal B.

The AND element 14 transmits the rotor reverse rotation prediction signal 21 to the control unit 15 only by inputting both the signal A and the signal B, and the control unit 15 turns off the motor 6 of the turning device 5. Perform

According to the reverse rotation detection system according to the first embodiment described above, both the abnormality occurrence signal B from the overcurrent detector 10 and the reverse rotation sign signal A from the arithmetic unit 13 indicate the reverse rotation of the rotor 3. Since the signal includes a sign of the start of rotation, the reverse rotation of the rotor 3 can be detected as a sign before the reverse rotation of the rotor 3 occurs, and the motor 6 of the turning device 5 is turned "OFF" in advance. By performing the control described above, the effect that the turning device 5 and the motor 6 can be reliably prevented from being damaged by the actual reverse rotation of the rotor 3 can be obtained.

In addition, no special instrument is required for reverse rotation detection, and a simple operation unit 13, existing overcurrent detector 10, pressure detectors Ps and Pd, and an AND element 14, etc., are generally used in a plant. Therefore, there is an effect that the apparatus can be configured at low cost.

FIG. 2 is a block diagram of a reverse rotation detection system according to a second embodiment of the present invention. In the second embodiment, the reverse rotation detection system 22 is configured by omitting the overcurrent detector system in the first embodiment shown in FIG.

In FIG. 2, the operation unit 13 of the reverse rotation detection system 22 fetches both pressure signals of the inlet pressure detector Ps and the outlet pressure detector Pd of the compressor unit 4 as in the case shown in FIG. The control unit 15 calculates the pressure difference and outputs only the signal having the k value or more as the reverse rotation prediction signal 23 directly.
The control unit 15 controls the motor 6 of the turning device 5 to be “OFF”.
Other configurations are the same as those of the first embodiment shown in FIG.

The abnormality occurrence signal B detected by the overcurrent detector 10 used in the first embodiment shown in FIG. 1 is detected including overcurrent occurrence due to other factors. On the other hand, the sign signal A detected by the calculation unit 13 has a greater influence on the prediction of the reverse rotation in that the sign of the reverse rotation is directly extracted from the pressure difference fluctuation at the inlet and the outlet of the compressor unit generated at the time of the reverse rotation of the rotor. .

In the second embodiment, by using only the reverse rotation sign signal obtained by the arithmetic unit 13 as the reverse rotation prediction signal 23, the system configuration can be simplified, and the system can be provided as an inexpensive and easy-to-use one. is there. Other functions and effects are the same as those of the first embodiment.

FIG. 3 is a block diagram of a reverse rotation detection system according to a third embodiment of the present invention. In the third embodiment, the AND element 1 in the first embodiment shown in FIG.
4 together with the detection signal B of the overcurrent detector 10 and the arithmetic unit 1
An OR element 16 connected in parallel to the detection signal A of No. 3;
Any one of the signals A and / or B passing through the AND element 14 and the OR element 16 is configured to be used as a reverse rotation sign prediction signal, and the motor 6 of the turning device 5 is controlled to be “OFF” via the control unit 15. It was done. Other configurations are the same as those of the first embodiment shown in FIG.

According to the third embodiment of the above configuration, in addition to the reverse rotation sign prediction signal 21 used in the AND element 14 of the system of the first embodiment, a detection signal A from the arithmetic unit 13 or an overcurrent An OR element 16 that outputs a reverse rotation sign prediction signal 25 when either one of the detection signals B from the detector 10 is input is provided in parallel, and an overcurrent detection signal B of the turning device motor 6 obtained through the OR element 16 is obtained. Is regarded as a danger warning signal by itself, and control for turning off the motor 6 of the turning device via the control unit 15 becomes possible.

Therefore, by using the configuration of the third embodiment, it is possible to provide a system capable of detecting the reverse rotation of the compressor unit 4 and detecting the abnormality of the turning device 5 and the motor 6 due to other factors.

[0032]

The reverse rotation detection system according to the present invention has the following features.
An inlet pressure detector and an outlet pressure detector for detecting the pressures at the inlet and the outlet of the compressor, and both pressure signals of the inlet and outlet pressure detectors are taken to obtain a difference between the two pressure signals. As described above, a computing unit that outputs a first sign signal that is regarded as a sign of occurrence of reverse rotation and a second sign signal that detects an overcurrent state of the motor that performs the turning operation of the compressor and regards it as a sign of occurrence of reverse rotation And an AND element that inputs the first and second sign signals and outputs a reverse rotation prediction signal when both signals are input, and performs the turning operation by a signal of the AND element. And a control unit for stopping the motor to be performed.

According to the above configuration, since both the first and second sign signals are signs including a sign that the reverse rotation of the rotor starts, it is possible to predict the reverse rotation before the rotor reversely rotates. This makes it possible to turn off the motor of the turning device in advance and to surely prevent the turning device and its motor from being damaged due to the actual reverse rotation of the rotor. Also, no special instrument is required for reverse rotation detection, and it can be dealt with with simple operation units, existing overcurrent detectors, pressure detectors, AND elements, and other equipment commonly used in plants. You can configure the system.

In (2) of the present invention, the overcurrent detector and the AND element of the above (1) are omitted, and only the reverse rotation sign signal obtained by the arithmetic unit is inverted by such a configuration. Since it is used as a rotation prediction signal, an overcurrent detector and an AND element are not required, and the same effects as those of the invention (1) can be obtained. Therefore, the system configuration can be simplified, and an inexpensive and easy-to-use system can be provided. The overcurrent signal used in the invention (1) is detected including the occurrence of overcurrent due to other factors. On the other hand, since the sign signal detected by the arithmetic unit directly extracts the sign of the reverse rotation of the rotor, it is greatly related to the prediction of the reverse rotation. In (2) of the present invention, since the control is performed only by the sign signal from the calculation unit, the system is simplified as described above.

In (3) of the present invention, the first sign signal from the arithmetic unit and the second sign signal from the overcurrent detector are output to an AND element and an OR element, respectively.
According to this system, the motor of the turning device is controlled to be turned "OFF" by one or both of the reverse rotation prediction signals obtained from the D element and the OR element. At the same time, abnormalities of the turning device and the motor due to other factors can be detected.

[Brief description of the drawings]

FIG. 1 is a block diagram of a reverse rotation detection system according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a reverse rotation detection system according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a reverse rotation detection system according to a third embodiment of the present invention.

FIG. 4 is a block diagram of a conventional reverse rotation detection system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Turbine type drive part 3 Rotor 4 Compressor part 5 Turning device 6 Turning motor 7 Clutch 10 Overcurrent detector 13 Operation part 14 AND element 15 Control part 16 OR element 20, 22, 24 Reverse rotation detection system

Claims (3)

[Claims] 1. An inlet pressure detector and an outlet pressure detector for detecting pressures at an inlet and an outlet of a compressor, and both pressure signals of the inlet and outlet pressure detectors are taken to obtain a difference between the two pressure signals.
When the pressure difference is equal to or greater than a predetermined value, a computing unit that outputs a first sign signal by regarding the sign as the occurrence of reverse rotation and detects an overcurrent state of the motor that performs the turning operation of the compressor, and detects the sign of reverse rotation. An overcurrent detector that outputs a second sign signal, an AND element that inputs the first and second sign signals, and outputs a reverse rotation prediction signal when both signals are input, and an AND element that outputs the reverse rotation prediction signal And a control unit for stopping the motor performing the turning operation in response to the signal of (1). 2. An inlet pressure detector and an outlet pressure detector for detecting pressures at an inlet and an outlet of a compressor, and pressure signals of the inlet and outlet pressure detectors are taken to obtain a difference between the two pressure signals.
When the pressure difference becomes equal to or more than a predetermined value, a calculation unit that outputs a reverse rotation prediction signal considering the occurrence of reverse rotation as a sign of reverse rotation and a motor that performs the turning operation of the compressor based on the reverse rotation prediction signal from the calculation unit is stopped. A reverse rotation detection system, comprising: a control unit. 3. The first symptom signal from the arithmetic unit and the second symptom signal from the overcurrent detector are respectively equal to the A signal.
Output to the ND element, and also output to the OR element in parallel, the control unit takes in the reverse rotation prediction signal from the AND element and the reverse rotation prediction signal from the OR element, and performs at least one of the two signals. The reverse rotation detection system according to claim 1, wherein the motor that performs the turning operation is stopped.