JPH0816563B2 - Surge detector for turbo refrigerator - Google Patents

Description

The present invention relates to a safety device for a turbo refrigerator, and more particularly to a surge detection device.

[Problems to be Solved by Prior Art and Invention]

Conventionally, in a turbo chiller, sometimes a surging phenomenon occurs due to infiltration of non-condensable gas into the machine, failure of a cooling tower, or extreme partial load operation, which causes a large amount of noise and vibration, resulting in smooth operation. Not only could it not be performed, but there was a problem such as damage to the bearing.

Therefore, despite the demand for a safety device that accurately detects the surging phenomenon and issues an alarm or the like that prompts countermeasures before the refrigerator is damaged, it has been conventionally required to accurately detect such a surging phenomenon and issue an alarm or the like. There was no safety device, or surge detection device, that emitted.

The present invention has been made in view of the above-mentioned points, and a surge is detected by detecting fluctuations in the current value of the main motor and rises in bearing temperature or lubricating oil temperature caused by a surge phenomenon, and checking the detected values from multiple angles. An object of the present invention is to provide a surge detection device for a turbo refrigerator that can accurately capture a phenomenon.

[Means for solving the problem]

In order to solve the above problems, the present invention has a surge detector for a turbo refrigerator configured as follows.

Current detection means for detecting the current of the main motor for driving the turbo refrigerator, abnormal current decrease detection means for detecting that the detected current value has abnormally dropped below the allowable value, and bearing temperature or lubricating oil temperature The temperature detection means and the abnormal temperature rise detection means for detecting from the output of the temperature detection means that the temperature abnormally rises beyond a specified value or the rise value for a certain time exceeds a specified value and abnormally rises. The present invention is characterized in that the abnormal current decrease detection means detects an abnormal decrease in the detected current value, and the abnormal temperature increase detection means provides an alarm means for issuing an alarm when it detects an abnormal increase.

Further, in place of the abnormal current decrease detection means, a counting means is provided for counting the number of times that the detected electric value has fallen out of the prescribed fluctuation allowable range within a certain time and has been recovered, and the alarm means is configured to count the number of the counting means. It is characterized in that the alarm is issued when the abnormal temperature rise detection means detects an abnormal rise as well as the count value is equal to or more than the specified count value.

[Action]

The current flowing through the main motor of the turbo refrigerator and the bearing temperature change as shown in FIG. That is, in the normal state, the current and the shaft temperature do not change, but if there is a periodic surging, the current value changes periodically (decreases) and the bearing temperature also changes (rises) periodically. In addition, if there is continuous surging, the current decrease continues and the temperature increase continues. Therefore, the surging phenomenon can be accurately grasped by multilaterally examining the fluctuation of the current value of the main motor and the rise of the bearing temperature or the lubricating oil temperature caused by the surging phenomenon. The surge detecting device of the present invention uses various means as described above, and accurately investigates the surging phenomenon because it multilaterally examines fluctuations in current value and rises in bearing temperature or lubricating oil temperature caused by such surging phenomenon. be able to.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a surging detection device of the present invention, and FIG. 2 is a block diagram showing the configuration of a turbo refrigerator having a surging detection device. As shown in the figure, the turbo refrigerator is configured to include a compressor 1 and an evaporator / condenser 10. The compressor 1 is configured to include an impeller 9 and a speed increaser 8. Reference numeral 3 is a bearing temperature detector that detects the temperature of the bearing 2 of the compressor 1, and 6 is a current detector that detects the current supplied from the main power supply 5 to the main motor 4. The outputs of the bearing temperature detector 3 and the current detector 6 are input to the controller 7. The control device 7 has the surging detection device of the present invention therein.

As shown in FIG. 1, the surging detecting device is a current value recording means for recording the detected current value detected by the current detector 6.
11, a bearing temperature value recording means 12 for recording the bearing temperature value detected by the bearing temperature detector 3, and a current value abnormality for detecting from the output of the current value recording means 11 that the current value has fallen below a specified allowable range. Output of current value fluctuation number detection means 14 and bearing temperature value recording means 12 for counting the number of times that the current value falls from the output of the current value recording means 11 The temperature rise detecting means 15 for detecting that the bearing temperature abnormally rises above the specified value is provided, and the output of the current value abnormal decrease detecting means 13, the current value variation number detecting means 14 and the temperature raising means 15 is It is input to the alarm means 16. The alarm means 16 issues an alarm when it detects that the bearing temperature has risen abnormally beyond the allowable range of the specified value, or when it has detected that the temperature rise value has exceeded the specified value within a certain period of time. Is made like.

As shown by the dotted line in FIG. 1, the bearing temperature detector 3
Instead of using the lubricating oil temperature detector 17 for detecting the temperature of the lubricating oil, the lubricating oil temperature value recording means 18 for recording the lubricating oil temperature detected by the lubricating oil temperature detector 17 is provided. The output of the value recording means 18 may be input to the temperature rise detecting means 15. In this case, the alarm means 16 sets one condition for issuing an alarm when it detects that the lubricating oil temperature exceeds the allowable range of the specified value and abnormally rises.

It is practically advantageous to construct the surging detection device shown in FIG. 1 by using a microcomputer, and the microcomputer is also used in this embodiment.
It goes without saying that the microcomputer is not an essential requirement, and the surging detection device may be configured by using other means.

FIG. 3 is a diagram showing an example of changes in the current (output of the current detector 6) flowing in the main motor 4 of the turbo refrigerator and the bearing temperature (output of the bearing temperature detector 3). As shown
In the normal state, the current and the shaft temperature do not change, but if there is periodic surging, the current value changes periodically (decreases) and the bearing temperature also changes (rises) periodically. Also,
With continuous surging, the current drop continues and the temperature rise continues. The operation of this surging detection device will be described below with reference to the processing flowchart of FIG. In this embodiment, the current value of the main motor 4 output from the current detector 6 is monitored during the monitoring time of about 10 seconds set by the program.
After A / D conversion, the data is sampled at intervals of about once per second (step ST1) and recorded in the battery recording means 11 composed of a memory (step ST2). Similarly, the bearing temperature detected by the bearing temperature sensor 3 is A / D converted and then sampled at intervals of about once a second (step ST3) and recorded in the bearing temperature value recording means 12 comprising a memory (step ST3). ST4). At the same time, the current value variation number detecting means 14 determines the number of times (abnormal variation number) that the minimum value of the current value has recovered below the lower limit of the preset allowable variation range D (see FIG. 3) of the current and has recovered again. Calculate (step ST5). Here, the lower limit value of the specified permissible fluctuation range of the current may be a constant value or may be changed depending on the load. In this way, it is determined whether the monitoring time set by the program has ended (step ST
6) After the monitoring time is over, the number of abnormal fluctuations is 2
It is judged whether or not it is three times or more (step ST7), and if it is less than the specified number of times, it is assumed that the surging phenomenon accompanied by the periodic current fluctuation as shown in FIG. 3 does not occur, and then the current value abnormally drops. Check whether it is not done (step ST8). If it is more than the specified value, it is assumed that there is no surging including the surging as shown in FIG. 3, and the record of the number of current fluctuations of the current value fluctuation number detecting means 14 is reset to zero (reset) (step). ST9), returns to the beginning of the program (step ST1) again, and repeats monitoring.

In the step ST7, the number of abnormal current fluctuations is 2 to
If it is three times or more, there is a possibility that periodical surging has occurred, and if the current value has abnormally decreased in step ST8, continuous surging has occurred. Therefore, the bearing temperature recorded in the memory which is the bearing temperature value recording means 12 is checked next, and it is determined whether the bearing temperature has momentarily increased and exceeded the preset temperature fluctuation range. Check (Step ST
10) If there is such a fact, it is judged that surging has occurred, and an alarm is issued (step ST13). If this is not the case, then, the temperature rise per unit time of the bearing temperature, for example, for 10 seconds of the sample time, that is, the temperature rise rate is calculated (step ST11), and then whether or not the value is equal to or more than the specified value It is determined (step ST12), and if it is equal to or larger than the specified value, it is determined that surging has occurred, and an alarm is issued (step ST13). If there is no abnormality in the temperature change of the bearing, it is assumed that the surging does not occur, the process returns to step ST9, and the record of the number of times of fluctuation of the current recorded in the memory of the current value fluctuation number detection unit 14 is reset to zero and the program Return to top (step ST1). When it is determined that surging has occurred as described above, an operation that sounds a buzzer as an alarm, or a failure signal is issued in the distance to prompt the refrigerator to be inspected and to stop the refrigerator to protect it. To do.

Further, when there is a circumstance where the refrigerator cannot be stopped, a hot gas bypass valve may be provided and opened to perform an operation of avoiding surgeons.

As described above, according to this surge detection device, the surging phenomenon of the turbo refrigerator can be accurately captured.

〔The invention's effect〕

As described above, according to the present invention, the surging phenomenon is accurately grasped by variably examining the fluctuation of the current value of the main motor caused by the surging phenomenon of the turbo refrigerator and the rise of the bearing temperature or the lubricating oil temperature. ,
Since the surging phenomenon can be avoided, the excellent effects of improving the durability of the turbo refrigerator and contributing to its long life can be obtained.

In addition, since the surging phenomenon of the turbo refrigerator can be monitored without having to obtain it, there is an effect that operating cost can be saved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a surging detection device of the present invention, FIG. 2 is a block diagram showing a configuration of a turbo refrigerator having a surging detection device, and FIG. 3 is a current flowing through a main motor of the turbo refrigerator. And FIG. 4 is a diagram showing an example of a change state of the bearing temperature, and FIG. 4 is a processing flowchart showing the operation of the surging detection device. In the figure, 1 ... Compressor, 2 ... Bearing, 3 ... Bearing temperature detector, 4 ... Main motor, 5 ... Main power supply, 6 ... Current detector, 7 ... Control device, 8 ... Gearbox, 9 ... impeller, 10
… Evaporation / condenser, 11 …… Current value recording means, 12 …… Bearing temperature value recording means, 13 …… Current value abnormal decrease detection means, 14 ……
Current value fluctuation number detection means, 15 ... Temperature rise detection means, 16
…… alarm means.

Claims (2)

[Claims] 1. A current detecting means for detecting a current of a main motor for driving a turbo refrigerator, an abnormal current decrease detecting means for detecting that the detected current value is abnormally decreased below a specified allowable value, and a bearing temperature. Or a temperature detecting means for detecting the lubricating oil temperature, and a temperature for detecting an abnormal increase in the temperature from the output of the temperature detecting means exceeding a specified value or an increase in a certain time exceeding the specified value. And an alarm means for issuing an alarm when the abnormal temperature rise detection means detects an abnormal rise in the detected current value and the abnormal temperature rise detection means detects an abnormal rise. The feature is a surge detector for turbo refrigerators. 2. A counter means for counting the number of times that the detected current value has fallen out of a prescribed fluctuation allowable range and dropped and recovered within a fixed time, in place of the abnormal current drop detection means, and the alarm means carries out the counting. The alarm is issued when the count of the means is equal to or greater than a prescribed count value and the abnormal temperature rise detection means detects an abnormal rise.
The surge detector for the turbo refrigerator described in.