JPH04101077A - Valve abnormality detecting method for reciprocating compressor - Google Patents

Abstract

PURPOSE:To enable the accurate diagnosis of valve abnormality during the operation of a reciprocating compressor by measuring the pulsating waveform of delivery pressure generated by the operation of a valve, and comparing its waveform pattern with that of a normal valve to detect the abnormality of a valve part. CONSTITUTION:The pulsating waveform of the delivery pressure of the valve of a reciprocating compressor 32 provided between a suction filter 31 and a receiver tank 33 is measured by a torsion gage type pressure sensor 34 with desirable frequency responsiveness fitted to the exhaust pipe 32A of the compressor 32 and recorded into a recorder 37 through an amplifier 35 and an oscilloscope 36. Its waveform pattern is then compared with that of a normal valve to detect the abnormality of a valve part. With this constitution, valve abnormality can be detected discriminating the uneven wear and partial falling of a valve plate causing gas leak from the defect of a valve spring and the attachment of debris to the valve plate causing change in the operation of the valve.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a valve abnormality detection method for a reciprocating compressor, and in particular,
The present invention relates to a valve abnormality detection method for a reciprocating compressor that can accurately diagnose abnormalities in valve parts such as suction valves and discharge valves of the reciprocating compressor while the reciprocating compressor is in operation.

[Prior Art] A cross-sectional view of a reciprocating compressor is shown in FIG. 4, and a cross-sectional view of a discharge valve used in the compressor is shown in FIG.

In Fig. 4, the interior of the housing 1 includes an intake chamber 2 and a compression chamber 3.
and an exhaust chamber 4, an intake pipe 6 is connected to the intake port 5 of the intake chamber 2, and an exhaust pipe 8 is connected to the exhaust lower of the exhaust chamber 4.
is connected. The compression chamber 3 has a cylindrical shape, and a piston 9 is slidably disposed inside the compression chamber 3.

A rod 10 is connected to the piston 9, and the reciprocating driving force from the drive device is transmitted to the piston 9 via the rod 10, thereby causing the piston 9 to reciprocate.

A vent 11 that communicates the compression chamber 3 with the intake chamber 2 and a vent 12 that communicates the compression chamber 3 with the exhaust chamber 4 are provided at one end of the cylindrical compression chamber 3 (upper end in FIG. 4). ing. The other end (lower end) of the compression chamber 3 is provided with a vent 13 that communicates the compression chamber 3 with the intake chamber 2 and a vent 14 that communicates the compression chamber 3 with the exhaust chamber 4 .

The vent 11.13 is provided with a suction valve 15.16, and the vent 12.14 is provided with a discharge valve 17.18.

When the piston 9 is stroked downward from the state shown in FIG. 4, the air in the chamber 3a on the rod end side of the compression chamber 3 is compressed. When the pressure within this chamber 3a exceeds the opening pressure of the discharge valve 18, the compressed air within the chamber 3a flows out into the exhaust chamber 4 and is discharged through the exhaust pipe 8. When the piston 9 descends, the suction valve 15 is opened, and air flows into the chamber 3b (not shown in the figure) located above the piston 9 and on the nozzle entrance side. (Of course, during this time, the suction valve 16 is closed. Also, the discharge valve 17 is also closed.) Conversely, when the piston 9 strokes upward, the suction valve 15 and the discharge valve 18 are closed. However, when the suction valve 16 opens and the pressure within the chamber 3b reaches a predetermined pressure, the discharge valve 17 opens and the compressed air flows out into the exhaust chamber 4.

In this way, air is discharged from the exhaust pipe 8 while pulsating every time the piston 9 reciprocates.

In addition, a plurality of compression chambers 3 are arranged in parallel,
The stroke phases of the inserted pistons 9 are different from each other.

In addition, as shown in FIG. 5, the discharge valves 17 and 18
A valve seat 21 having a valve seat 21, a valve plate 22 that is movable toward and away from the valve seat 21, a valve portion 24, and a valve plate 22 that biases the valve plate 22 in the seating direction. Spring 23 and valve seat 2
1, a threaded shaft 25 with a valve portion 24 supported thereon; and a nut 2 screwed onto the shaft 25.
It is equipped with 6th class.

By the way, as shown in Fig. 4, in a compressor with a structure in which two or more cylindrical compression chambers are arranged in parallel, even if the valves of some compression chambers become abnormal and leakage occurs, the valves of the remaining compression chambers are normal. If so, the pressure will rise as specified, so it is not possible to detect a valve abnormality from the pressure gauge display. In this state, although the compressor functions satisfactorily, if the valves in the remaining compression chambers also malfunction, the pressure will immediately drop, causing a sudden failure.

For this reason, it is necessary to carry out planned equipment maintenance by detecting valve abnormalities early, that is, before compressor failure occurs, using a method other than the average pressure displayed by a pressure gauge. It is said that

Conventionally, a problem with a valve in a reciprocating compressor has been determined by a skilled inspector based on intuition by listening to the sound of the valve operating. That is,
If an abnormality such as a crack or a defect occurs in the valve, the impact sound generated between the valve body and the valve seat will be different from the normal sound.
Skilled inspectors estimate the condition of the valve by listening to the sound it makes with a stethoscope.

In addition, there is a method of diagnosing the condition of a valve by installing a vibration sensor near each valve and observing the vibration waveform of the valve (Japanese Patent Application Laid-open No. 75373/1983).

[Problems to be solved by the invention] The method of determining an abnormality by relying on the intuition of an expert based on the change in sound when the valve is activated requires a long time to train an expert;
The need to gain experience with each target device;
Furthermore, there is a problem in that even an experienced and skilled person may not be able to make very accurate judgments.

Furthermore, in the diagnosis method based on observing the vibration waveform of the valve, since the valve vibration is attenuated at a position far from the valve, it is necessary to install a vibration sensor very close to the valve to measure the valve vibration. However, in actual reciprocating compressors, the valve portion is covered with a casing or a safety cover, and it is difficult to install a vibration sensor very close to the valve. For this reason, it is often difficult to sample and observe valve vibrations with little damping.

In order to implement this method, it is necessary to install a vibration sensor in advance when assembling the reciprocating compressor, which has the disadvantage of requiring a great deal of effort and expense. Moreover, even if a vibration sensor is provided in advance in this manner, it is not possible to detect an abnormality very accurately.

The present invention solves the above-mentioned conventional problems, does not rely on the intuition of the operator, and does not require vibration signals from the valve.
It is an object of the present invention to provide a valve abnormality detection method for a reciprocating compressor that can accurately diagnose valve abnormalities during operation of the reciprocating compressor.

[Means for Solving the Problems] The method for detecting valve abnormality in a reciprocating compressor according to claim (1) is a method for detecting abnormality in a valve section of a reciprocating compressor, wherein the discharge pressure generated by the operation of the valve is detected. The method for detecting valve abnormality in a reciprocating compressor according to claim 2, characterized in that the abnormality in the # part is detected by measuring the pulsation waveform of the valve and comparing the waveform pattern with the waveform pattern of a normal valve. The method according to claim (1) is characterized in that the pulsating waveform of the discharge pressure is measured by a strain gauge type pressure sensor.

[Operation] Since the valve of the reciprocating compressor repeats opening and closing periodically, its discharge pressure is pulsating. That is, when the discharge valve opens, high-pressure gas within the cylinder is released, resulting in a pressure increase. On the other hand, when the discharge ends and the valve closes, the pressure decreases. The pulsating waveform of this discharge pressure changes depending on the operation of the discharge valve and the presence or absence of leakage.

For this reason, by comparing the waveform patterns with the pulsating waveform of the discharge pressure of a normal valve as a reference, it is possible to detect malfunction of the valve and the presence or absence of leakage.

In particular, the pulsating waveform of the discharge pressure can be measured with high accuracy and good response using a strain gauge type pressure sensor with good frequency response.

[Examples] Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram illustrating a method for detecting valve abnormality in a reciprocating compressor according to the present invention. As shown in the figure, in this embodiment, a suction filter 31 and a receiver tank 32 are used.
The pulsating waveform of the discharge pressure of the valve of the reciprocating compressor 32 provided between the ) was measured using a strain gauge type pressure sensor 34, passed through an amplifier 35, an oscilloscope 36, and recorded with a recorder 37.

The measurement of the pulsating waveform of the discharge pressure was carried out by setting the following valve abnormalities to a valve having a normal valve plate 40 as shown in FIG. 2(a).

■ Uneven wear of the valve plate (as shown in Figure 2 (b), in the case of valve plate 40A where the valve plate is partially worn) ■ Partial fall off of the valve plate (as shown in Figure 2 (C), the valve plate (In the case of valve plate 40B with a partially missing valve) ■ Missing valve spring (when only one of the three valve springs is installed) ■ Foreign matter adhering to the valve plate (overlapping two valve plates to reduce the weight) Figure 3 shows the measurement results for each of the above cases.
Shown in a) to (d).

The following is clear from FIGS. 3(a) to 3(d). In each of the graphs in FIGS. 3(a) to 3(d), among the three waveforms, the waveforms at both ends are the waveforms of normal valves, and the central waveform is the waveform of "abnormal valves."

As shown in Figures 3(a) and (b), in case of valve abnormality causing gas leakage such as uneven wear or partial fall off of the valve plate,
During suction, gas enters the cylinder from the discharge valve side,
The amount of gas in the cylinder increases, the discharge pressure and the discharge amount also increase, and the amplitude becomes larger. Also, since the gas in the cylinder is not released instantaneously, the waveform is smoother than that of a normal valve.

In addition, as shown in Figures 3 (C) and (d), when there is an abnormality that changes the valve operation, such as a loss of the valve spring or foreign matter adhering to the valve plate, the opening/closing timing of the valve changes. ,
The shape of the waveform itself has changed compared to the waveform shape of a normal valve.

From the above results, it is clear that abnormalities such as gas leakage and changes in valve operation can be accurately detected from changes in the pulsating waveform of the discharge pressure.

[Effects of the Invention] As detailed above, according to the valve abnormality detection method for a reciprocating compressor of the present invention, the state of the valve of a reciprocating compressor can be accurately diagnosed while the reciprocating compressor is in operation. This makes it possible to detect valve abnormalities at an early stage, reliably prevent sudden failures of reciprocating compressors, and take appropriate maintenance measures.

According to the method of claim (2), valve abnormality can be detected more accurately.

[Brief explanation of drawings]

Fig. 1 is a system diagram illustrating an implementation method of the valve abnormality detection method for a reciprocating compressor of the present invention, Fig. 2(a) is a plan view showing a normal valve, and Fig. 2(b) is a plan view showing an abnormal valve. Cross-sectional view shown in Figure 2 (
C) is a plan view showing the abnormal valve, Fig. 3 is a graph showing the pulsating waveform of discharge pressure, Fig. 4 is a sectional view of the reciprocating compressor, and Fig. 5 is a plan view showing the abnormal valve.
The figure is a sectional view of the discharge valve. 31... Suction filter 32... Reciprocating compressor, 33... Receiver tank, 34... Strain gauge pressure sensor

Claims (2)

[Claims] (1) A method for detecting abnormalities in the valve section of a reciprocating compressor, by measuring the pulsating waveform of the discharge pressure generated by the valve operation, and comparing the waveform pattern with the waveform pattern of a normal valve. A valve abnormality detection method for a reciprocating compressor, characterized by detecting an abnormality in a valve section. (2) The method for detecting valve abnormality in a reciprocating compressor according to claim (1), wherein the pulsating waveform of the discharge pressure is measured by a strain gauge type pressure sensor.