JP4847766B2 - Method and apparatus for determining strainer clogging - Google Patents

Description

  The present invention relates to a strainer clogging determination method and apparatus, and more specifically, in a fluid circuit including a throttle and a strainer disposed on the primary side of the throttle, and having one end opened to the atmosphere and used as a fluid discharge port. The present invention relates to a method and an apparatus for determining whether or not a strainer provided in the fluid circuit is clogged.

  As an example, in the compressor 1 having the compressor main body 10 that compresses air or other compressed gas together with oil or water, the oil or water discharged from the compressor main body 10 and compressed as shown in FIG. A gas supply circuit 30 ′ is provided for introducing the gas into the separator receiver tank 20 and separating it from oil or water, and then introducing the gas into an air working machine (not shown).

  In the case of a compressor having a so-called “oil-free” type compressor body that does not require the oil or water described above when compressing the compressed gas, the separator receiver tank 20 in FIG. Compressed gas discharged from the compressor main body 10 can be directly introduced into an unillustrated air working machine or the like, and the discharge port 11 of the compressor main body 10 and the pneumatic work receiving the supply of compressed gas from the compressor main body 10 The aforementioned compressed gas supply circuit 30 'is formed between the machines (not shown).

  A cooler 31 is provided in the compressed gas supply circuit 30 ′. The compressed gas flowing in the supply circuit 30 ′ is cooled by the cooler 31, and is condensed when cooled by the cooler 31. Moisture in the generated compressed gas is collected as a drain in a drain separator 32 or a dryer 33 (drain separator 32 in FIG. 2), and a dry compressed gas from which moisture has been removed can be introduced into an unillustrated air working machine. Yes.

  Further, the collected drain is communicated with the supply circuit 30 ′ through the drain separator 32, for example, by connecting the other end 40b of the drain discharge circuit 40 whose one end 40a is opened to the atmosphere to the inside of the supply circuit 30 ′. It can be discharged out of the machine together with a part of the flowing compressed gas.

  In the compressor 1 having an oil-free compressor body, unlike the compressor described with reference to FIG. 2, in order to obtain a high-pressure compressed gas, the compressor body is arranged in a plurality of stages. The compressed gas compressed in the stage compressor body 10a is further introduced into the high pressure stage compressor body 10b and compressed (see FIG. 3).

  In the multistage compressor 1 configured as described above, not only when the compressed gas is introduced from the high-pressure stage compressor body 10b to the external air working machine or the like, but also from the low-pressure stage compressor body 10a. The circuit 30 for introducing the compressed gas to the compressor body 10b of the stage is also provided with a cooler 31 and a drain separator 32 in the same manner as described above, and collects the drain generated by the cooling by the cooler 31 and collects it. A similar drain discharge circuit 40 for discharging the collected drain to the outside of the apparatus is provided.

  In the drain discharge circuit 40 configured as described above, the compressed gas supply circuit 30 ′ or the circuit 30 communicating between the low-pressure and high-pressure compressor bodies 10a and 10b is used as a main circuit. Since it is configured as a branch circuit branched from this circuit, in the present invention, the main circuit (the circuits 30, 30 ′ in the above example) is designated as the “main circuit” for the branch circuit such as the drain discharge circuit 40. "

  In the drain discharge circuits 40 and 40 'described above, the throttles 41 and 41' are provided in the circuits, and the drain discharge circuits 40 and 40 'are connected to the outside through the open ends 40a and 40a'. The amount of compressed gas discharged is limited to prevent a pressure drop in the main circuits 30 and 30 ′.

  In order to prevent the throttles 41 and 41 ′ having a diameter of about 1 mm provided in the drain discharge circuits 40 and 40 ′ from being clogged with dust or the like contained in the drain or compressed gas, the throttles 41 and 41 are used. A strainer 42 is provided on the upstream side of ', and the drain or compressed gas after removing dust and the like by the strainer 42 is introduced into the throttles 41 and 41'.

  In the present invention, the “throttle” refers to all of the orifices provided in the circuit as well as those that restrict the flow path, and may be provided, for example, in the circuit as long as it has an action of restricting the flow path. In addition, electromagnetic valves, on-off valves, and the like also correspond to the term throttle in the present application.

  By the way, when the strainer 42 provided as described above is clogged, the drain collected by the drain separator 32, the dryer 33, etc. is not discharged outside the machine, and the drain is discharged together with the compressed gas to the main circuits 30, 30 ′. Are introduced into the external air working machine or the compressor main body 10b of the high-pressure stage, causing problems such as malfunctioning of the external air working machine.

  In particular, in the above-described multistage compressor in which oil-free compressor bodies that do not require the introduction of water or oil are arranged in multiple stages as described above, the compressed gas containing such a drain is compressed in a high-pressure stage. When introduced into the machine main body 10b, the compressor main body 10b rusts and causes a serious failure.

  Therefore, the strainer 42 provided in such a drain discharge circuit 40 needs to be maintained so as not to be clogged, for example, by periodically cleaning it, and this work is a burden on the operator.

  As a method for detecting clogging of the strainer provided in the fluid flow path, a pressure sensor is provided on each of the primary side and the secondary side of the strainer, and the primary side pressure and the secondary pressure detected by the two pressure sensors are detected. It has been proposed to detect clogging based on a pressure difference from the secondary pressure (see Patent Documents 1 and 2).

  In addition, when the oil filter is clogged, a relief valve is provided that opens a circuit that circulates the oil without going through the oil filter. When the relief valve is opened, the oil filter is clogged. Can be detected (see Patent Document 3).

Prior art document information of the present invention includes the following.
JP 2002-153713 A JP-A-6-71120 JP 7-34491 A

  In the conventional clogging detection method configured as described above, in the method of detecting clogging of the strainer by the pressure difference between the primary side and the secondary side of the strainer as described in Patent Documents 1 and 2, Two pressure sensors are required to detect the pressure on the primary side and the secondary side of the strainer, respectively, which complicates the configuration and increases the cost due to the increased number of parts.

  In addition, a control unit (Patent Document 1) or a microcomputer (Patent Document 2) is provided to receive a detection signal output from each pressure sensor and determine clogging. Is a comparison of signals from each pressure sensor and judgment of clogging based on this, and the processing performed by the control unit and microcomputer is complicated, and the control with relatively high processing capability that enables such complicated processing is possible. It becomes a factor of further cost increase, such as the necessity to install a unit and a microcomputer.

  On the other hand, in the configuration shown in Patent Document 3, when the relief valve is opened by the primary pressure of the oil filter that rises when the oil filter is clogged, the operation of the relief valve is detected to detect the oil filter. In the drain discharge circuit provided in the compressor as described above, if the flow of the main circuits 30 and 30 'is secured, the strainer 42 is clogged. However, the primary pressure of the strainer 42 does not increase. For this reason, even if a relief valve is provided on the primary side of the strainer 42, the relief valve does not operate due to clogging of the strainer 42, and the configuration shown in Patent Document 3 is based on the strainer provided in the drain discharge circuit of the compressor. It cannot be used for clogging detection.

  Accordingly, the present invention has been made to solve the above-described drawbacks of the prior art, and by providing a method and apparatus that can determine strainer clogging with a relatively simple configuration, the number of parts can be reduced. Another object of the present invention is to provide a strainer clogging determination method and apparatus capable of simplifying the processing performed by the control means.

In order to achieve the above object, the method for detecting clogging of the strainer 42 of the present invention comprises a throttle 41 for limiting the amount of compressed fluid discharged together with the drain, and a strainer 42 disposed on the primary side of the throttle 41. In the branch circuit 40 , one end 40a is opened to the atmosphere to form a fluid discharge port, and the other end 40b communicates with the main circuit 30 for introducing a compressed fluid of a predetermined pressure into the fluid machine.
Monitoring the pressure in the branch circuit 40 between the throttle 41 and the strainer 42;
The pressure in the branch circuit 40 between the throttle 41 and the strainer 42 is equal to or lower than a reference pressure (first reference pressure in the embodiment) set to a predetermined pressure lower than the pressure in a state where the strainer 42 is not clogged. In this case, it is determined that the strainer 42 is clogged (Claim 1).

The branch circuit 40 is a compressor body 10 (10a, 10b) of the compressor 1 or another fluid machine (for example, an air working machine that operates upon receiving compressed gas supply from the compressor 1), When the compressor body is a low-pressure stage compressor body 10a of a multistage compressor, the compressor body 10a is compressed against the high-pressure stage compressor body 10b that receives the introduction of compressed gas from the low-pressure stage compressor body 10a. communicating the other end 40b to the main circuit 30 for introduction of a fluid, for example, when a circuitry such as a drain discharge circuit 40, the determination of clogging of the strainer 42, to perform the full-load operation of the compressor 1 (Claim 2).

Further, when the branch circuit 40 has the other end 40b communicated with the main circuit 30 for introducing the compressed fluid from the compressor main body of the compressor 1 or the separator receiver tank 20 to another fluid machine, The pressure in the main circuit 30 is monitored, and after the pressure in the main circuit 30 exceeds a second reference pressure set to a predetermined pressure equal to or higher than the reference pressure (first reference pressure), the strainer 42 Clogging may be determined (claim 3).

Further, it is determined that the strainer is clogged when the pressure in the branch circuit 40 between the strainer 42 and the throttle 41 is not more than the first reference pressure continuously for a predetermined time. (Claim 4).

The strainer clogging determination device according to the present invention includes a throttle 41 for limiting the amount of compressed fluid discharged together with the drain, and a strainer 42 arranged on the primary side of the throttle 41, and opens one end 40a to the atmosphere. In a branch circuit that forms a fluid discharge port and communicates the other end with a main circuit that introduces a compressed fluid of a predetermined pressure into a fluid machine.
When the strainer 42 is not clogged, it is detected that the pressure is equal to or lower than a reference pressure (first reference pressure) set to a predetermined pressure lower than the pressure in the branch circuit 40 between the throttle 41 and the strainer 42. First pressure detecting means 52 for outputting a detection signal is provided in the branch circuit 40 between the throttle 41 and the strainer 42;
When a detection signal that is equal to or lower than the reference pressure is received from the first pressure detection unit 52, it is determined that the strainer 42 is clogged, for example, a determination unit 61 realized by an electronic control unit is provided. (Claim 5).

Further, the branch circuit 40 introduces the compressed fluid from the compressor main bodies 10 and 10b of the compressor 1 or the separator receiver tank 20 to another fluid machine (such as an air working machine or a high-pressure stage compressor main body 10b). the main circuit 30 communicates with the other end 40b, for example, when a circuitry such as a drain discharge circuit 40,
The compressor 1 may include a canceling unit 62 that does not cause the determination unit 61 to determine that the strainer 42 is clogged when the compressor 1 is in a no-load operation state.

Further, if the branch circuit 40 is a circuitry communicating the other end 40b to the main circuit 30 for the introduction of the compressed fluid from the compressor body or separator receiver tank 20 to the other of the fluid machine of the compressor 1, The main circuit 30 is provided with second pressure detecting means 54 for outputting a detection signal exceeding a second reference pressure set to a predetermined pressure equal to or higher than the reference pressure (first reference pressure). ,
A configuration including a canceling unit 62 that does not allow the determination unit 61 to determine that the strainer is clogged until a detection signal exceeding the second reference pressure is received from the second pressure detection unit 54. (Claim 7).

  Further, a counter 61a is provided for counting the reception continuation time of the detection signal that has become equal to or lower than the reference pressure from the first pressure detection means 52, and when the predetermined time is counted by the counter, the determination means 61 The strainer 42 may be determined to be clogged (Claim 8).

  According to the configuration of the present invention described above, the strainer clogging determination method and apparatus of the present invention have the following effects.

By using the pressure in the branch circuit 40 on the secondary side of the strainer 42 for determination, the number of pressure detection means (first pressure detection means 52) such as a pressure switch and a pressure sensor can be reduced, and Since clogging can be determined based on a detection signal that is lower than the reference pressure from the first pressure detecting means 52 provided on the secondary side of the strainer 42, pressure comparison is performed when determining clogging. There is no need to do.

  As a result, compared to the conventional determination method that required comparing the pressure on the primary and secondary sides of the strainer, the processing to be performed by the control means used for the determination, for example, an electronic control unit such as a control unit, is simplified. I was able to do it.

A circuit (main circuit) in which the branch circuit 40 including the strainer 42 to be determined for clogging introduces compressed fluid from the compressor main body 10 or 10a of the compressor 1 or the separator receiver tank 20 to another fluid machine. 30 communicating with, for example, when a branch circuit such as drainage circuit 40, and the no-load operation of the compressor 1, and the like immediately after the transition to full-load operation from no-load operation, the drain discharge circuit 40 is branched circuit Since the clogging of the strainer 42 is not determined when the pressure is equal to or lower than the reference pressure (first reference pressure), erroneous determination can be suitably prevented.

  Furthermore, when the pressure on the secondary side of the strainer 42 is below the reference pressure (first reference pressure) continuously for a predetermined time, it is determined that the strainer is clogged temporarily. It was possible to suitably prevent misjudgment caused by fluctuations in pressure, for example, pulsation of compressed gas discharged from the compressor main bodies 10 and 10a.

  Next, embodiments of the present invention will be described below with reference to the accompanying drawings.

In the following embodiment, the clogging determination device of the present invention will be described as determining clogging of the strainer 42 of the drain discharge circuit 40 provided in the oil-free multistage compressor 1. The determination method and apparatus of the present invention is used for determining clogging of a strainer provided in a drain discharge circuit in a compressor other than an oil-free compressor, for example, an oil-cooled or water circulation compressor 1 described with reference to FIG. It is not limited to a compressor drain discharge circuit, and one end is open to the atmosphere, and in a branch circuit having a throttle, it can be generally applied to the determination of clogging of a strainer provided on the primary side of the throttle. is there.

[Overall configuration of compressor]
In FIG. 1, reference numeral 1 denotes an oil-free multistage compressor. The compressor 1 includes two compressor bodies 10a and 10b, and sucks outside air through one compressor body (low pressure stage) 10a. The compressed air obtained by the compression by the low pressure stage compressor body 10a is introduced into the other compressor body (high pressure stage) 10b and further compressed to obtain high pressure compressed air. It is configured to be able to.

  In order to enable such multi-stage compression, an unloader 70 and an air filter 80 are communicated with the intake port 12a of the low-pressure stage compressor body 10a so that outside air can be introduced through the air filter 80. , A circuit (main circuit) 30 is provided to communicate the discharge port 11a of the low-pressure stage compressor body 10a and the intake port 12b of the high-pressure stage compressor body 10b, and the compressed air obtained by the low-pressure stage compressor body 10a The high pressure stage compressor body 10b can be introduced.

  A circuit 30 ′ is connected to the discharge port 11 b of the high-pressure stage compressor body 10 b for supplying compressed air to an unillustrated air working machine or the like.

  In the present embodiment, the aforementioned unloader 70 is controlled to be opened and closed by a hydraulic cylinder 71, and an electromagnetic switching valve that controls the introduction of hydraulic oil from an oil supply source (not shown) to the hydraulic cylinder 71. 72 is provided, and the unloader 70 can be opened and closed by inputting a control signal from the control means 60 described later to the electromagnetic switching valve 72.

  The main circuit 30 that communicates between the discharge port 11 a of the low-pressure stage compressor body 10 a and the intake port 12 b of the high-pressure stage compressor body 10 b is provided with a cooler 31. The compressed air passing through the main circuit 30 can be cooled.

  And the drain separator 32 is provided in the secondary side of the said cooler 31, and the drain in the compressed air aggregated by the cooling at the time of passing through the said cooler 31 can be collected.

  Further, the drain separator 32 communicates with the other end 40b of the drain discharge circuit 40 whose one end 40a is opened to the atmosphere, and this drain discharge circuit 40 constitutes a branch circuit branched from the main circuit 30. The drain collected by the drain separator 32 via the drain discharge circuit 40 is configured to be discharged out of the apparatus together with a part of the compressed air in the main circuit 30.

  The drain discharge circuit 40 is provided with a throttle 41 to limit the amount of compressed air discharged together with the drain to prevent a pressure drop in the main circuit 30 and to prevent the throttle 41 from being clogged. A strainer 42 is provided on the primary side of the throttle 41, and drain and compressed air that has passed through the strainer 42 are introduced into the throttle 41.

  The reference numeral 44 in the drain discharge circuit is a check valve, and the drain discharge circuit is caused by the negative pressure in the main circuit 30 generated by driving the high-pressure compressor body 10b during no-load operation with the unloader 70 closed. The outside air is prevented from being inhaled from one end 40a of 40.

[Judgment device]
1. Basic Configuration In the drain discharge circuit 40 of the compressor 1 configured as described above, a pressure detection means (first pressure detection) for detecting the pressure in the drain discharge circuit 40 at this position is between the strainer 42 and the throttle 41. Means) 52 is provided.

  In the drain discharge circuit 40 in which the one end 40a is opened to the atmosphere, the pressure in the circuit 40 on the one end 40a side is atmospheric pressure so that a change in pressure cannot be detected. However, as described above, the first pressure detecting means 52 Is provided on the primary side of the throttle, the pressure in the drain discharge circuit 40 can be increased on the primary side of the throttle 41, and a change in pressure can be detected. Further, by arranging the first pressure detecting means 52 on the secondary side of the strainer 42, a change in the secondary pressure of the strainer 42 caused by the clogging of the strainer 42 can be detected, and based on this, the strainer 42 clogging can be determined.

The first pressure detecting means 52 is a reference pressure (first reference pressure) set to a predetermined pressure lower than the pressure in the branch circuit 40 between the throttle 41 and the strainer 42 in a state where the strainer 42 is not clogged. This is a pressure switch that operates, and when the pressure between the strainer 42 and the throttle 41 drops from a high state to a pressure lower than the first reference pressure, the contact of the pressure switch is switched to cause a change in the output electrical signal. The electrical signal changes as follows: the contact operates from OFF to ON or ON to OFF to output an electrical signal (ON signal), or stop the output of the electrical signal (OFF signal), ON, OFF Including changes between them. For example, when the pressure is lower than the first reference value, the contact of the pressure switch is operated from OFF to ON to output an electrical signal (ON signal), and this ON signal may be used as a detection signal. On the contrary, the pressure switch contact may be operated from ON to OFF to stop the output of the electric signal when the value is below the first reference value, and the output stop (OFF signal) of this electric signal may be used as the detection signal. . As an example, in the compressor 1 used in the present embodiment, the pressure in the drain discharge circuit 40 between the throttle 41 and the strainer 42 in a state in which the strainer 42 is not clogged is 0.2 MPa. In the embodiment, the first reference pressure is set to a predetermined pressure of less than 0.2 MPa.

  The first reference pressure may be selected or set by the user according to, for example, the purpose of use and usage of the compressor 1, and the user selects how much clogging is to be performed and determines that it is clogged. You may comprise so that it may obtain. In this case, the user sets the pressure close to the pressure between the throttle 41 and the strainer 42 (0.2 MPa in the above example) in a state where the strainer 42 is not clogged. It is possible to determine that clogging occurs at a stage close to the use limit of the strainer 42 as the pressure is set to a low value.

  In the present embodiment in which the pressure between the throttle 41 and the strainer 42 is 0.2 MPa as described above in a state where the strainer 42 is not clogged, the first reference pressure is set to 0.1 MPa as an example. By setting, it is not determined that clogging occurs so frequently, and it is possible to prevent the introduction of drain into the high-pressure compressor body 10b.

  The detection signal of the first pressure detection means 52 configured in this way is input to a control means 60 such as an electronic control device that controls the operation of each part of the compressor 1 according to a preset program, for example. The realized determination means 61 determines that the strainer 42 is clogged by receiving a detection signal that is equal to or lower than the first reference pressure of the first pressure detection means 52.

  Upon receiving such a determination, the control signal output means 63 realized in the control means 60 is lit on a display means 90 such as a warning light 91 and a sound alarm 92 provided on a control panel (not shown) of the compressor 1, for example. And a control signal for generating a warning sound, and a control for causing the compressor 1 to perform an emergency stop in place of the output of the control signal to the display means 90 or together with the output of the control signal to the display means 90 Output a signal.

2. Additional Configuration In the configuration described above, only the components that are common in the configuration of the strainer clogging determination device of the present invention are described even when applied to a branch circuit provided in a device other than the compressor 1, As shown in the figure, when the clogging of the strainer 42 provided in the drain discharge circuit 40 of the compressor 1 is determined, the second pressure detection means 54 for detecting the pressure in the main circuit 30 is provided together with the above-described configuration. At the same time, it is preferable to further realize each means described below by the control means 60.

(1) Second Pressure Detection Unit The second pressure detection unit 54 can be configured by a pressure switch or a pressure sensor, and the pressure in the main circuit 30 is a predetermined pressure that is equal to or higher than the first reference pressure. Is detected and the detection signal is output.

  In the present embodiment, the second reference pressure of the second pressure detecting means 54 is set to 0.1 MPa, which is the same as the first reference pressure, and it is detected that the second reference pressure has been exceeded and a detection signal is output. Thus, it is possible to detect that the pressure in the main circuit 30 exceeds the second reference pressure.

(2) Canceling means As described above, in the drain discharge circuit 40 communicating with the main circuit 30 communicating between the low-pressure stage compressor body 10a and the high-pressure stage compressor body 10b, the unloader 70 During no-load operation in which the inlet 12a of the compressor body 10a is closed, compressed air is not introduced into the main circuit 30 from the compressor body 10a. The main body 30 is sucked by the compressor main body 10b, and the pressure in the main circuit 30 is in a reduced state.

  Accordingly, the pressure in the drain discharge circuit 40 communicating with the main circuit 30 is also reduced, and the pressure in the drain discharge circuit 40 between the strainer 42 and the throttle 41 is related to whether or not the strainer 42 is clogged. First, the pressure is lower than the first reference pressure, and the first pressure detection means 52 is in a state of outputting a detection signal lower than the first reference pressure.

  Therefore, during such no-load operation, even if the determination unit 61 determines that the strainer 42 is clogged based on a detection signal from the first pressure detection unit 52 that is equal to or lower than the first reference pressure, the correct determination can be made. I can't make it happen.

  Further, even if the unloader 70 opens the intake port 12a of the low-pressure stage compressor body 10a and the compressor 1 shifts from no-load operation to full-load operation, the pressure in the main circuit 30 does not immediately increase, and at least the main circuit 30 Until the internal pressure exceeds the first reference pressure, the pressure in the drain discharge circuit 40 is also equal to or lower than the first reference pressure, and the first pressure detecting means 52 detects that the pressure is lower than the first reference pressure. A signal is output.

  Therefore, as in the case of the above-described no-load operation, even if the determination unit 61 determines that the strainer 42 is clogged in such a state, the correct determination cannot be made.

  Therefore, in the present embodiment, when it is not appropriate to cause the determination unit 61 to determine the clogging of the strainer 42 as described above, the determination unit 61 is clogged with the strainer. Canceling means 62 that does not make a determination is provided to prevent malfunction of the compressor based on an erroneous determination.

  That is, the above-described canceling means 62 confirms that the unloader 70 is in a closed state based on, for example, the output state of a control signal to the electromagnetic switching valve 72 that controls the opening and closing of the unloader 70, and the compressor is in a no-load operation. At this time, the determination unit 61 is not determined to be clogged with the strainer.

  Even after the compressor 1 shifts from no-load operation to full-load operation, until the detection signal from the second pressure detection means 54 for detecting the pressure in the main circuit 30 is received, that is, the main circuit. 30 pressure exceeds the second reference pressure set to a predetermined pressure equal to or higher than the first reference pressure (in this embodiment, exceeds the second reference pressure set to the same pressure as the first reference pressure) The canceling means 62 is configured not to make the determination means 61 determine the clogging of the strainer 42 until it is confirmed.

(3) Counter Further, the determination means 61 clogs the strainer 42 based on the temporary pressure change generated in the drain discharge circuit 40 due to the pulsation of the compressed air discharged from the compressor body 10a. In order to prevent the determination, the counter 61a for counting the reception duration time of the detection signal from the first pressure detection means 52 is realized in the control means 60, and the counter 61a sets the set time (in this embodiment). Is determined so that the determination means 61 determines whether clogging occurs.

[Operation]
When the compressor 1 equipped with the strainer clogging determination device of the present invention configured as described above is started, the canceling means 62 realized by the control means 60, for example, an electromagnetic switching valve 72 for controlling the opening and closing of the unloader 70. It is determined whether or not the compressor 1 is in a full-load operation state according to the control signal output to, and whether or not a detection signal exceeding the second reference pressure is received from the second pressure detection means 54. Based on this, it is determined whether or not the pressure in the main circuit 30 exceeds the second reference pressure. When the compressor 1 is in a no-load operation state or even in a full-load operation state, When the pressure is equal to or lower than the second reference pressure, the determination unit 61 does not determine that the strainer is clogged by the cancel unit 62.

  When the compressor 1 is in full load operation and the pressure in the main circuit 30 exceeds the second reference pressure, the restriction by the canceling means 62 on the judging means 61 is released, and the judging means 61 is activated, The determination unit 61 waits for reception of a detection signal that is equal to or lower than the first reference pressure from the first pressure detection unit 52.

  When the pressure on the secondary side of the strainer 42 drops below the first reference pressure due to clogging or pulsation of compressed air in the strainer 42 provided in the drain discharge circuit 40, the first pressure detection means 52 detects the detection signal. When the detection signal is received, the control means 60 activates the counter 61a to start counting the reception duration of the detection signal.

  If the reception continuation time counted by the counter 61a is less than the predetermined time (5 seconds), the determination unit 61 waits for reception again until the next detection signal is received.

  On the other hand, when the counter 61a continuously counts the reception of the detection signal for a predetermined time (in this embodiment, 5 seconds), the determination unit 61 determines that the strainer 42 is clogged.

  When it is determined by the determination means 61 that the strainer 42 is clogged, the control signal output means 63 realized by the control means 60 is used to turn on the warning light 91, which is the display means 90, for example. A control signal for causing the sound device 92 to generate a warning sound is output.

  The control signal output means 63 of the control means 60 outputs a control signal for emergency stop of the compressor 1 in place of the output of the control signal to the display means 90 or together with the output of the control signal to the display means 90. Emergency stop.

  Note that such display by the display means 90 or emergency stop of the compressor 1 may be configured to be performed by selecting either one according to conditions set in advance by an operation by the operator. By storing this setting in advance in a storage means provided, the control means 60 may be configured to operate according to this setting.

[Others]
In the embodiment described above, the main circuit 30 is a conduit that communicates between the low-pressure stage compressor body 10 a and the high-pressure stage compressor body 10 b, and the drain discharge circuit 40 that communicates with the main circuit 30 is used as the main circuit 30. An example is shown in which the provided strainer 42 is determined to be clogged. For example, in FIG. 1, the compression port 10b is connected to the discharge port 11b of the high-pressure stage compressor body 10b and an air working machine (not shown). The air supply circuit 30 ′ may be the main circuit described above, and the strainer 42 provided in the drain discharge circuit 40 ′ communicated with the main circuit may be determined for clogging. In this case, the strainer The first pressure detecting means 52 is disposed between the valve 42 and the electromagnetic valve (throttle) 41 ′. Further, in such a configuration, the pressure in the drain discharge circuit 40 'is higher than that in the above-described embodiment (as an example, 0.7 to 0.8 MPa). Change the setting of each reference pressure according to.

  Further, when the clogging determination apparatus of the present invention is applied to a single-stage compressor as shown in FIG. 2, the clogging determination method and clogging determination apparatus of the present invention can be similarly applied. Similarly, since the pressure in the drain discharge circuit 40 is higher than that in the above-described embodiment, the setting of each reference pressure is changed accordingly.

  The strainer clogging determination method and determination apparatus according to the present invention described above can be used to detect clogging of the strainer in general pipes having a strainer and a throttle and having one end opened to the atmosphere. In a multi-stage compressor using an oil-free compressor, more preferably, drains generated in the pipe line connecting the low-pressure stage compressor body and the high-pressure stage compressor body are discharged. Therefore, it is suitable for detecting the clogging of the strainer of the drain discharge circuit provided for the purpose.

The whole block diagram of the compressor provided with the clogging determination apparatus of this invention. The schematic circuit diagram of the conventional compressor (oil cooling type or water circulation type). The schematic circuit diagram of the conventional compressor (oil-free type multistage type).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 10 Compressor body 10a Low pressure stage compressor body 10b High pressure stage compressor body 11, 11a, 11b Discharge port 12, 12a, 12b Inlet port 20 Separator receiver tank 30 Main circuit 30 ′ Compressed air supply circuit 31 Cooling 32 Drain separator 33 Dryer 40 branch circuit (drain discharge circuit)
40 'drain discharge circuit 40a one end [of branch circuit (drain discharge circuit)]
40b The other end [of the branch circuit (drain discharge circuit)]
41 Restriction (orifice)
41 'throttle (solenoid valve)
42 Strainer 44 Check Valve 52 First Pressure Detection Unit 54 Second Pressure Detection Unit 60 Control Unit 61 Determination Unit 61a Counter 62 Cancellation Unit 63 Control Signal Output Unit 70 Unloader 71 Hydraulic Cylinder 72 Electromagnetic Switching Valve 80 Air Filter 90 Display Unit 91 Warning light 92

Claims (8)

A throttle restricting the amount of compressed fluid discharged together with the drain and a strainer arranged on the primary side of the throttle are provided, one end is opened to the atmosphere to form a fluid discharge port, and the other end is applied to the fluid machine at a predetermined pressure. In a branch circuit communicating with the main circuit for introducing the compressed fluid of
Monitoring the pressure in the branch circuit between the throttle and the strainer;
When the pressure in the branch circuit between the restrictor and the strainer becomes equal to or lower than a reference pressure set to a predetermined pressure lower than the pressure when the strainer is not clogged, the strainer is clogged. The strainer clogging judgment method that judges that it is present. The branch circuit is a circuitry communicating the other end to the main circuit performing the introduction of the compressed fluid from the compressor body or separator receiver tank to the other of the fluid machine of the compressor,
The strainer clogging determination method according to claim 1, wherein the determination of clogging of the strainer is performed during full load operation of the compressor. The branch circuit is a circuitry communicating the other end to the main circuit performing the introduction of the compressed fluid from the compressor body or separator receiver tank to the other of the fluid machine of the compressor,
The pressure in the main circuit is monitored, and the strainer is clogged after the pressure in the main circuit exceeds a second reference pressure set to a predetermined pressure equal to or higher than the reference pressure. Strainer clogging judgment method. 4. The method according to claim 1, wherein when the pressure in the branch circuit between the strainer and the throttle is not more than the reference pressure continuously for a predetermined time, it is determined that the strainer is clogged. Strainer clogging judgment method. A throttle restricting the amount of compressed fluid discharged together with the drain and a strainer arranged on the primary side of the throttle are provided, one end is opened to the atmosphere to form a fluid discharge port, and the other end is applied to the fluid machine at a predetermined pressure. In a branch circuit communicating with the main circuit for introducing the compressed fluid of
A first pressure detection that detects that the strainer is below a reference pressure set to a predetermined pressure lower than the pressure in the branch circuit between the throttle and the strainer when the strainer is not clogged and outputs a detection signal Means is provided in the branch circuit between the throttle and the strainer;
A strainer clogging determination device comprising: a determination unit that determines that the strainer is clogged when a detection signal that is equal to or lower than the reference pressure is received from the first pressure detection unit. . The branch circuit is a circuitry communicating the other end to the main circuit performing the introduction of the compressed fluid from the compressor body or separator receiver tank to the other of the fluid machine of the compressor,
6. The strainer clogging determination device according to claim 5, further comprising canceling means for preventing the determination means from determining that the strainer is clogged when the compressor is in a no-load operation state. . The branch circuit is a circuitry communicating the other end to the main circuit performing the introduction of the compressed fluid from the compressor body or separator receiver tank to the other of the fluid machine of the compressor,
Second pressure detection means for detecting that the pressure in the main circuit has exceeded a second reference pressure set to a predetermined pressure equal to or higher than the reference pressure and outputting a detection signal is provided in the main circuit;
A canceling unit is provided that does not allow the determination unit to determine that the strainer is clogged until a detection signal exceeding the second reference pressure is received from the second pressure detection unit. The strainer clogging determination device according to claim 5 or 6.   There is provided a counter for counting the reception continuation time of the detection signal that has fallen below the reference pressure from the first pressure detection means, and when the predetermined time has been counted by the counter, the determination means looks at the strainer. The strainer clogging determination device according to any one of claims 5 to 7, wherein it is determined that clogging has occurred.

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