JPS62153583A - Abnormality detecting method and device for reciprocation type compressor - Google Patents

Abstract

PURPOSE:To make it possible to easily detect an abnormality in a reciprocation type compressor, by providing a vibration sensor on the cylinder head of the compressor, and by monitoring electrical signals from the sensor. CONSTITUTION:A vibration sensor 10B is attached to a head attaching bolt 10D on the cylinder head section 10 of a reciprocating compressor, and delivers an output signal which is delivered in a computer 60 for comparing a peak value of the signals with a previously memorized value to discriminate the presence of an abnormality. When the computer 60 determines that an abnormality occurs, the output signal is delivered to lamps 50, 53, 55 indicating that the abnormality is due to vibration.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] [Prior Art] Refrigeration machines in supermarkets and the like often use reciprocating compressors that use fluorocarbons as a refrigerant.

The configuration of such a fluorocarbon refrigerator is shown in FIG. The fluorocarbon refrigerator consists of a compressor 1, a condenser 2, an expansion valve 3, an evaporator 4, and an accumulator 5.

The compressor 1 is of a reciprocating type, and sucks in and compresses refrigerant fluorocarbon by reciprocating a piston within a cylinder. The condenser 2 condenses and liquefies refrigerant vapor at high temperature and cylinder pressure obtained from the compressor 1. The heat at this time is removed with cooling water. The expansion valve 3 reduces the pressure of the room temperature high pressure liquid refrigerant from the condenser 2 . The evaporator 4 evaporates this low-pressure, low-temperature fluorocarbon refrigerant, extracts heat of evaporation from the surroundings, and converts it into low-pressure steam. The accumulator 5 has the function of separating the liquefied fluorocarbon refrigerant contained in the fluorocarbon refrigerant sucked into the next-stage compressor 1 and sending only the fluorocarbon refrigerant gas to the compressor 1. The compressor 1 takes in this fluorocarbon gas and compresses it.

The most serious and difficult-to-recovery abnormality in such a refrigerator includes damage to the compressor 1. Among the causes of damage, the most significant and difficult to detect and protect are liquid hammer and oil hammer. Once this hammer condition occurs, it will deal a fatal blow to the compressor within a very short period of time.

Conventionally, maintenance measures against compressor damage, particularly hammer phenomenon, include the following.

(i) Measure the temperature and determine whether it is normal or abnormal.

(a) Example of temperature measurement of intake air and discharge air from a showcase. (b) Example of temperature detection using a thermal protector built into a compressor and protection based thereon.

(ii) Ensure safety by measuring pressure or comparing measured values.

(a) Pressure switch (discharge gas pressure, hydraulic pressure) (ii
i) Ensure safety by monitoring current.

(a) An example in which safety is ensured by an overcurrent circuit breaker G that operates when the operating current of the compressor becomes abnormally large.

(iv) Inspection by supervision by a skilled person.

(a) Abnormal noise (b) Abnormal vibration (c) Frosted condition Each of the above conventional examples is a definitive solution.) III
However, due to the principle of refrigerators, the operating state changes slightly depending on the heat load and the installation conditions of the equipment. Furthermore, if we take into account factors over time, it is necessary to make decisions based on an understanding of daily, monthly, and seasonal changes from the start of operation. Therefore, each of the above methods may be a sufficient solution (although there are many cases where a combination method is used. In other words, in addition to mechanical monitoring such as various automatic detections as described in (i) to (iii), (iv) ) In many cases, this method is combined with manual monitoring.

However, this combination method also has the following drawbacks.

(1) The final determination of normality or abnormality must be made by an expert.

(ii) The characteristics of each refrigerator must be understood.

(iii) Operation monitoring is required for a relatively long period of time. On the other hand, since there is no protection device with a highly accurate response, protection against sudden liquid or oil hammers caused by abnormal conditions is extremely low.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to detect vibrations and discharge temperature of a compressor (oil hammer, liquid hammer), and to detect an abnormality in the compressor from both of them.

[Embodiments of the invention]

FIG. 2 is a diagram showing an embodiment of the present invention in which a vibration sensor and a temperature sensor are attached to a two-cylinder compressor. A vibration sensor IOB was attached to a part of the cylinder head 10 of the compressor 1 at a position close to the piston 14.

The compressor 1 is of a two-cylinder type, and two pistons 13, 14 are shown in the figure. The head part 10 is for intake,
Having a discharge chamber inside, intake by piston 13, 14,
Compressed discharge is performed.

A suction pipe 11 is a pipe for sucking fluorocarbon refrigerant gas, and a discharge pipe 12
is a pipe that discharges compressed fluorocarbon refrigerant vapor.

In order to connect the head portion 10 and the cylinder portion including the piston, they are fastened with bolts 10A. The figure shows an example of eight bolts. A vibration sensor IOB was attached to one of the bolts.

FIG. 3 shows a diagram of the relationship between the bolt to which the vibration sensor IOB is attached and other bolts. The other bolts do not have protruding heads, but Pol l-1 is equipped with a vibration sensor IOB.
0D has a prominent head. A heat insulating material 10C was provided to wrap around the head, and a vibration sensor IOB was further attached to the top of the heat insulating material 10C.

The vibration sensor IOB detects the acceleration of vertical vibration.

Therefore, extremely rapid change components in the vibration are extracted.

FIG. 4 shows an overall configuration diagram of the compressor. The compressor 100 consists of a compressor main body 110, a compressor cylinder head 10, and a valve plate assembly 105.

A valve connects the compressor cylinder head 10 and the compressor main body 110.

This is the board composition part 105. A bolt 10 is used as the connecting means.
A. There are IOCs, etc.

Furthermore, the valve plate assembly 105 includes a suction valve 10H and a discharge valve 1.
0G, the suction valve 10H sucks the fluorocarbon refrigerant from the suction pipe 11, and the discharge valve 10G discharges the compressed refrigerant from the discharge pipe 12.

The compressor main body 110 has a crankcase 102. Inside this crankcase 102 are two cylinders for two cylinders.
There are two cylinder chambers 10F and IOM, and the cylinder chambers 10F and IOM are attached to which the piston 14.13 performs suction and compression.A motor 101 is used to drive the piston 14.13.
There is. Power is supplied from the power terminal section 104, and the motor 101 is driven to move the pistons 13, 14 up and down to perform suction and compression in the cylinder chambers 10F and 10M.

Oil is supplied into the crankcase 102 from an oil pump 103 for circulating the piston.

Additionally, a crankcase heater 110 is installed to raise the temperature of oil in the crankcase while the motor 101 is stopped.
Set it up. Depending on the scale of the compressor, there are cases where the crankcase heater 110 is not provided.

A vibration sensor IOB was attached to the head of Pol l-10D via a heat insulating material 10C. The vibrations occur mainly due to the impact energy generated when the liquid is compressed in the shaded area of the discharge valve 10G. This vibration is caused by the installation
The vibration is transmitted to the IOD, and then to the vibration sensor IOH, where the acceleration of the vibration is detected.

The heat insulating material 10C is provided to eliminate the influence of the internal temperature of the head 10 on the vibration sensor IOB.

In the case of a two-cylinder engine as shown in the figure, the vibration sensor IOB generates vibrations caused by two types of vibration: vibration caused by the impact energy when the liquid is compressed by the piston 14, and vibration caused by the impact energy when the liquid is compressed by the piston 13. Detect. Piston 13
Inhalation and compression by and 14 are not simultaneous inhalation and simultaneous compression, but are performed alternately. A series of suction and compression strokes by these two pistons together form one stroke.

On the other hand, in FIG.
2B is adhesively fixed, and a heat insulating material 12A is provided around the temperature sensor 12B. This heat insulating material 12A is provided to eliminate the influence of ambient temperature on the temperature sensor 12B and to truly detect only the internal discharge temperature of the discharge pipe 12.

FIG. 5 is a diagram showing an example of an electrical signal detected by vibration sensor IOB. The vibration sensor IOB is installed to detect vibrations in the vertical movement direction of the piston. Therefore, the content of the vibration is determined by the synchronous rotational speed of the synchronous motor 101 serving as the piston drive source and the number of cylinders.

The vibrations of the refrigerant, oil, etc. passing through the valve are added to this. FIG. 5(A) is a waveform diagram during normal operation, and FIG. 5(II+) is a waveform diagram when liquid hammer and oil hammer are occurring. P,
, P2 are vibration waveforms generated during normal compression. P,
is a vibration component (acceleration) due to refrigerant compression on the piston 14 side, and a vibration component (acceleration) due to refrigerant compression on the P, H piston 13 side. The reason why the peak values differ between P and P2 is that the vibration sensor IOB is attached to a position close to the piston 14 side. These P,,P, occur every stroke of the piston. On the other hand, when liquid hammer or oil hammer occurs, Pl has a large amplitude like P3 and its vibration time is longer than P, and P2 has a large amplitude like P4 and its vibration time is also longer than P2. It is longer compared to Therefore, in this embodiment, the peak value of each vibration wave is monitored,
It was decided that abnormality detection would be performed by comparing the size with a predetermined reference value for abnormality determination.

Next, an overall embodiment of the present invention will be described. FIG. 6 shows an overall embodiment of the present invention. In this embodiment, temperature sensor 1
2B detects the discharge temperature in the discharge pipe, the vibration sensor IOB detects the vertical vibration (Jj) of the piston, and captures the compressor movement state. Abnormality detection is performed by monitoring these three states.

The converter 30 takes in the discharge temperature detected by the temperature sensor 12B and performs preamplification processing and AD conversion processing. The temperature comparator 35 compares the lower limit set temperature that indicates an abnormality with the converter 3 in advance.
The detected discharge temperature is compared with the detected discharge temperature of 0, and a temperature abnormality signal "1" is output only when the detected discharge temperature is lower than the lower limit set temperature.

AND gate 38 indicates temperature abnormality signal of comparator 35 “1”
It is turned on by the "1" output of the delay timer 34 and causes the temperature abnormality indicator 50 (or necessary contact output) to display an abnormality. The "1" output of the delay timer 34 is a condition for turning on the power to the compressor motor 101. Actually, as shown in the figure, the value obtained is obtained by shaping the state of the power switch by a waveform shaping circuit 33 and applying a certain delay by a timer 34. The delay time of the delay timer 34 is due to the fact that the discharge temperature has not reached a sufficient upper limit and is not stable immediately after the compressor is started. did.

The converter 31 takes in the vibration signal detected by the vibration sensor IOB, performs preamplification, and AD converts it. The output of the converter 31 is input to a display 52 to display the absolute value of the vibration value. . Furthermore, the vibration value which is the output of this converter 31 is
Input to comparator 32.

The comparator 32 successively takes in the vibration values output from the converter 31, and first detects the peak value. Furthermore, the comparator 32
compares the detected peak value with predetermined abnormality determination reference values H, M, and L. The relationship t-Naz is H>M>L. H is a reference value in the case of abnormally large vibrations caused by a liquid hammer or an oil hammer, a so-called reference value for severe failure.

In this case, an emergency stop of the compressor is required.

M is a reference value for moderate vibrations and is a warning requirement.

L is a reference value for an abnormality in which the vibration is larger than the normal value, but smaller than H and M, and appears over a long period of time, and the discharge temperature becomes low at that time. By detecting this, it is determined that there is a possibility that a hammer condition will occur in the near future. This L value detection is also subject to an alarm.

When the peak value Sp≧H, the lamp 53 (or contact output) displays an indication that vibration has occurred due to a serious failure.

When the peak value Sp is M≦Sp<H, the lamp 54 displays an indication that vibration has occurred due to a moderate failure.

When the peak value Sp is L≦Sp<M, the AND gate 37 is opened and the lamp 55 indicates that a small abnormal vibration is occurring, provided that the output of the AND gate 38 is “1”. Display.

In addition, a configuration is adopted in which an alarm is issued in common when an abnormality occurs in any of L, M, and H. Or gate 39, alarm 36
fulfills its function. The alarm is issued by a buzzer 56 and also as a contact output.

The contact output in each configuration (lamp 50, 53, 54, 55. and alarm circuit 36 output) shown in FIG. It is used to make something happen.

When the indicator lamp 53 is lit, the motor 101 is immediately turned off and stopped immediately. When the indicator lamp 54 is lit, the device is turned off and a complete inspection is performed. When the indicator lamp 55 lights up, a warning is given that an inspection is required at an early stage.

FIG. 7 is a diagram showing an example of processing by a computer.

The temperature sensor 12B and the vibration sensor 1 are connected via the input circuit 61.
0B, take in compressor operating status G (200).

The computer 60 performs certain processing and outputs the result to various display/alarm units 63 via an output circuit 62 to display/alarm. The configuration of the display/alarm 63 is the same as that in FIG.

A processing flowchart by the computer 60 is shown in FIG.

First, check whether the discharge temperature detected by the temperature sensor 12B is below the lower limit setting, and if it is below the lower limit setting, check the power supply state and check the time elapsed (T,) for entering the operating state.
When both conditions are met, the buzzer 56 issues an alarm.

Further, the lamp 50 is turned on.

On the other hand, the detected vibration signal of vibration sensor IOB and H,M.

A comparison is made with each setting value of L, and three status signals are obtained according to the respective comparison results. If there is an H output, the emergency stop warning lamp 53 is turned on.

If there is an M output, the lamp 54 is turned on.

If the temperature is below the lower limit temperature and there is an L output, the lamp 55 is turned on.

The relationship between reference values H, M, and L and various abnormalities will be explained in detail.

(a) Relationship with comparison standard value H.

This standard value I (is the so-called critical failure judgment standard value. If a serious failure is left untreated, it will cause damage to the compressor equipment. The causes are as follows. First of all, the refrigerant This is when there is an abnormality in the construction of the piping.In this case, condensed liquid refrigerant and oil may accumulate in the compressor suction piping.

If the compressor is restarted in this state, a large amount of the liquid refrigerant and oil will return to the compressor during this restart.
The liquid is compressed inside, and vibrations with a vibration peak value equivalent to or higher than the reference value H are generated.

Second, the compressor may undergo a short cycle during winter when the refrigeration load is reduced. A short cycle means that the compressor repeatedly starts and stops in a short period of time even when the compressor drive morph is powered on. When a short cycle occurs, a large amount of oil for lubricating the piston in the compressor's crankcase is discharged into the refrigerant circuit (the entire system in Figure 1), and a mixture of refrigerant liquid and oil accumulates on the suction pipe side, causing this abnormality. Sometimes, vibrations equivalent to or higher than the reference value H occur during startup. Third, the crankcase heater is disconnected, or in a compressor without a crankcase heater, a large amount of liquid refrigerant dissolves in the oil in the compressor crankcase while the compressor is stopped. In this case as well, upon restart, vibrations equivalent to or greater than the reference value H occur.

In other words, the reference value ■] is connected to such a serious failure and is set to detect vibration.

If such a serious failure is left untreated, it will cause damage to the compressor equipment. That is, the suction valve, the discharge valve, and even the piston rod are damaged, and the compressor becomes unusable. In the present invention, the reference value H
Since it is possible to detect the occurrence of a vibration value (acceleration value) of a considerable or higher value, it is now possible to discover serious failures in advance. This provides clues for preventing damage to the piston and discovering abnormalities in construction.

(0) Relationship with comparison standard value M.

Liquid refrigerant may enter the compressor crankcase when too much refrigerant is added manually (overcharging) or when the refrigeration load is abnormally small. In this case, the liquid refrigerant in the case heater evaporates inside the crankcase. As a result, the compressor body is covered with frost. If the device is restarted under this condition, vibrations equivalent to or greater than the reference value M (below H) will occur. Therefore,
Such an abnormality can be detected based on the reference value M.

In addition, in the case of the above abnormality, H
Vibration equivalent to or greater than the value may occur. It would be good if it could be detected with the basic value (1) mentioned in (a) above, but the detection is difficult because the time span is narrow. However, in the above-mentioned abnormality, vibrations equivalent to or greater than the reference value M continue for a long time, and therefore can be detected using the reference value M.

(c) Relationship with comparison standard value.

If there is a large amount of liquid refrigerant returning to the compressor due to a small frosted Amagasaki refrigeration load on the evaporator or malfunction of the expansion valve, the H value will not be detected, but after restarting the compressor, the H value will be equal to or higher than the standard value (M The following vibrations occur. Although failure detection may be determined based only on this reference value, the compressor discharge gas temperature tends to decrease as the state of liquid compression progresses. Therefore, in this example, the standard value is equivalent to or higher than the standard value (
Abnormality is detected when the temperature of the discharged gas becomes equal to or less than the specified value. This alarm prompts inspection of the refrigeration cycle. Furthermore, there are other advantages to taking this discharge gas temperature into account. That is, even if the compressor is normal (that is, even if it is not compressing liquid), it is detected only for a short time when the refrigeration load is large, such as in summer. This detection can be considered as a malfunction, and in order to prevent such malfunction, it is necessary to lower the discharge temperature.

Next, the mode of failure occurrence will be described.

FIG. 9 shows the situation when the serious failure described in (a) occurs. Upon start-up, a vibration of a serious failure that can be detected at the reference value H first occurs, and then progresses to the H-M-L-normal value. In most serious malfunctions, the occurrence of vibrations that can be detected at the reference value H often results in damage to the equipment. however,
This does not happen at all when the reference value H is detected, but when H-M
-L- Sometimes things return to normal. This depends on the degree of abnormality.

In this latter case, H is detected instantaneously only at startup, and normal operation is restored. However, in the process, the 2M value,
Abnormalities can often be detected using the L value.

FIG. 10 shows an aspect of the case described in (rJ) above. H appears at startup and irregularly thereafter.

Vibration for M detection is occurring most of the time, and M detection is often performed. Further, the H-equivalent value may not occur.

FIG. 11 shows the embodiment in (c) above. At startup, M detection may be possible, but most of the time it is vibration for L detection. Furthermore, the discharge pipe temperature T is a specified value T. A warning will be issued when this happens.

The various waveforms described above are data for abnormality detection, and the judge can take appropriate measures against the abnormality depending on the content of the data.

Base! The iζ values H, M, and L are examples of a two-cylinder compressor, and if the number of cylinders changes, the values themselves may vary in size and cases other than three may occur. In addition, although the vibration sensor was used to detect acceleration, we believe that speed detection is also possible.

Although the explanation has been given using an example of a refrigerator, the present invention can also be applied to detecting an abnormality in a reciprocating compressor used for something other than a refrigerator.

〔Effect of the invention〕

According to an example using the vibration sensor of the present invention, abnormalities in a reciprocating compressor can be detected with high accuracy. In addition, by combining it with a temperature sensor, it has become possible to predict liquid hammer and oil hammer.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of the overall configuration of a refrigerator, Fig. 2 is a diagram showing the attachment of the vibration sensor and temperature sensor of the present invention to the cylinder head of the compressor, and Fig.
Vibration detection waveform diagram during stroke, Figure 6 is an overall embodiment of the present invention, Figure 7 is a diagram of an embodiment of the present invention using a computer, Figure 8 is a flowchart diagram of a computer, and Figures 9 to 11. FIG. 2 is an explanatory diagram of various abnormality detection modes. 10...Compressor head, IOB... [6
Sensor, 11... Suction pipe, 12... Discharge pipe, 12B
...Temperature sensor. Patent Applicant Kyodo Technology Center Co., Ltd. Representative Patent Attorney Tadashi Akimoto Figure 1 Home Figure 2 Figure 3 Figure 5 Figure 7 Figure 12B 2δ0 Figure 8 Figure 9 Figure 10 n Figure 11

Claims (1)

[Claims] 1. A vibration sensor attached to the cylinder head of a reciprocating compressor detects vibrations in the vertical movement direction of the compressor piston as an electrical signal, and monitors the peak value of the electrical signal to control the compressor. A method for detecting abnormalities in reciprocating compressors by detecting abnormalities. 2. A reciprocating compressor, a vibration sensor attached to the cylinder head of the compressor to detect vertical vibration of the piston, a temperature sensor attached to the discharge pipe of the compressor to detect the temperature inside the discharge pipe, and a compressor abnormality. A comparison circuit that detects an abnormality by comparing the vibration reference value and the peak value of the vibration detection signal obtained from the vibration sensor, and displays an abnormality based on the output of the comparison circuit and the temperature detected by the temperature sensor. An abnormality detection device for a reciprocating compressor consisting of an indicator and an indicator. 3. The abnormality detection device for a reciprocating compressor according to claim 2, wherein the reciprocating compressor has two cylinders.