JP5203117B2 - Drain discharge method and drain discharge mechanism of air compressor - Google Patents

Description

  The present invention relates to a drain discharge method and a drain discharge mechanism of an air compressor, and more specifically, in an air compressor including a cooling means for cooling before supplying compressed air obtained by a compressor body to a consumer side. The present invention relates to a drain discharging method and a discharging device in an air compressor for discharging drain generated during cooling by the cooling means to the outside of a compressed air supply system.

  In a compressor having a compressor main body that compresses air, compression heat is generated when air is compressed by the compressor main body, and the temperature of the compressed air discharged from the compressor main body rises. Since the dew point temperature of the air is high, condensation is likely to occur when it is cooled, and when compressed air that has been discharged from the compressor body is supplied to the consumer side, the compressed air is cooled in the supply pipe and drained. There was a risk that the pneumatic equipment would be damaged by this drain. Therefore, all the compressed air supplied to the consumer side is cooled in advance, and the water vapor in the compressed air is condensed by this cooling to generate and remove the drain. A small amount of compressed air is supplied.

  As an example, the oil-cooled screw compressor 1 will be described as an example. The oil-cooled screw compressor 1 is configured such that two screw rotors are engaged with each other in a cylinder so as to be rotatable, and lubricating oil is placed in the cylinder. The compressor main body 10 is provided to seal, cool, and lubricate the compression working space by being introduced. The compressor main body 10 is provided with a drive source 60 such as an engine and a motor for driving the compressor main body 10. A receiver tank 70 that introduces compressed gas discharged together with the lubricating oil and separates the compressed air and the lubricating oil is provided. The compressed air separated from the lubricating oil in the receiver tank 70 is connected to an air working machine or the like. A supply circuit 81 for supplying compressed air in the receiver tank is provided so that it can be supplied to the consumer side.

  The supply circuit 81 is provided with cooling means such as an aftercooler 22 and a dryer 23 for cooling the compressed air from the receiver tank 70, and drain discharge for discharging the drain generated by the cooling means out of the supply system. A valve 5 is provided (see FIGS. 7 and 8).

  As such a drain discharge mechanism, for example, a float type drain trap is provided, and when the float rises when a predetermined amount of drain accumulates, the drain discharge port opens and drains by a mechanical control method. The discharge timing and discharge time are also controlled.

  However, with such a mechanical control method, if dirt or corrosion (rust generation) occurs due to aging in the link mechanism of the float and the on-off valve, malfunction will occur and operation reliability will be increased. May decrease.

  Therefore, instead of such mechanical control, it has also been proposed to provide a drain valve by providing a solenoid valve in the drain discharge path and electrically controlling the opening and closing of the solenoid valve.

  As an example of such a drain discharge method, an integration counter that counts and accumulates the operation time of the air compressor is provided, and when the integration time counted by the integration counter reaches a set value, a drain discharge that discharges the drain is performed. A configuration in which the valve is configured to open for a certain period of time has been proposed (see Patent Document 1).

  As another example, every time a preset time set by a timer elapses, the control valve provided in the drain discharge flow path is opened to open and close the drain discharge valve, and the secondary side of the drain discharge valve is also opened. There has been proposed a configuration in which the drain discharge valve is closed regardless of the elapsed time of the timer when the pressure sensor provided in the sensor detects a pressure equal to or higher than the set pressure (see Patent Document 2).

Prior art document information of the present invention includes the following.
JP-A-11-351497 JP 2003-97444 A

  Among the conventional technologies described above, in the drain discharge method introduced as Patent Document 1, the integrated operation time of the air compressor is counted, and an on-off valve (electromagnetic valve) that discharges drain when the integrated time reaches the set time. Because the valve is configured to be open, malfunctions associated with aging of the link mechanism, etc. occur as in the case where the discharge timing is controlled by a mechanical control method such as a float. The problem is solved.

  However, the amount of drain generated due to cooling of the compressed air increases with an increase in the amount of outside air sucked into the compressor body, an increase in the outside air temperature and humidity that is sucked in, and a decrease in the amount of outside air sucked into the compressor body. Decreases with decreasing outside air temperature and humidity.

  In the configuration described in Patent Document 1, the compressor main body is operated at a constant rotation speed, and the capacity of the compressor is controlled by opening and closing the suction port of the compressor main body. Since the amount of outside air sucked into the main body is proportional to the full load operation time of the air compressor, the accumulated operation time of the air compressor is counted, and drain is discharged when the accumulated operation time reaches a certain time. Thus, every time the intake air amount to the compressor body becomes constant, drain is discharged, and the change in the drain generation amount accompanying the change in the intake air amount can be dealt with.

  However, even if the drain is discharged every time the amount of intake air to the compressor body becomes constant, the amount of generated drain changes if the temperature and humidity of the intake air change.

  For this reason, in the invention described in Patent Document 1, it is not possible to cope with such a change in the amount of generated drain, and the actual amount of generated drain is larger than the planned amount of generated drain. In this case, the total amount of drain generated by one opening / closing operation of the drain discharge valve cannot be discharged, and in this case, the drain is mixed into the compressed air supplied to the consumption side.

  On the other hand, if the actual drain generation amount is smaller than the planned drain generation amount, the on-off valve is maintained open even after the drain discharge is completed, so that compressed air is discharged. Thus, unnecessary power consumption is performed such as a pressure drop in the receiver tank and a full load operation to compensate for such a pressure drop.

  In contrast to the drain discharge mechanism described in Patent Document 1 configured as described above, the drain discharge mechanism described in Patent Document 2 completes drain discharge and introduces compressed air into the drainage path. The pressure on the secondary side of the on-off valve is detected by a pressure sensor, and when such a pressure rise occurs, the on-off valve Therefore, it is possible to eliminate the significant pressure drop that accompanies the mass release of compressed air.

  However, in the above configuration, the on-off valve closing operation is performed only after the secondary pressure of the on-off valve rises above a predetermined pressure, that is, only after the compressed air is discharged. This will cause a pressure drop.

  In the configuration described in Patent Document 2, the pressure sensor detects an increase in the secondary side pressure of the on-off valve, although the above-described function is exhibited when the amount of drain generated is less than the planned amount. Otherwise, the on-off valve is closed at the set time set by the timer. Therefore, if the actual drain generation amount exceeds the planned drain generation amount, the on-off valve is opened and closed once. The total amount of drain cannot be discharged, and the drain remaining without being discharged in this way is accumulated and eventually introduced into the consumer side together with the compressed air.

  Therefore, the present invention has been made to eliminate the above-described drawbacks of the prior art, and not only changes in the amount of outside air introduced into the compressor body, but also the amount of drain generated due to changes in the operating environment of the air compressor. In response to changes, drains can be discharged efficiently, and energy is lost due to pressure drop due to compressed air discharge, and drains are introduced to the consumer side along with compressed air due to insufficient drainage. It is an object of the present invention to provide a drain discharge method and a drain discharge mechanism for an air compressor that can suitably prevent this.

In order to achieve the above object, the drain discharge method of the air compressor 1 of the present invention comprises a cooling means 22 for cooling the compressed air discharged from the compressor body 10 before supplying it to the consumption side, and includes a drain discharge valve. In the drain discharge method of the air compressor for discharging the drain generated in the cooling means 22 by repeating the opening and closing operation of No. 5,
Correspondence relationship between the temperature of the intake air or the change in temperature and humidity and the change in the amount of drain generated per unit time in the full load operation of the air compressor 1, and the drain discharge amount per unit time of the drain discharge valve 5 Ask in advance,
Measure the temperature or temperature and humidity of the intake air, measure and accumulate the full load operation time of the air compressor, and based on the correspondence, the measured temperature or temperature and humidity and the full load operation From the accumulated time, the amount of drain generated per unit time, and the amount of drain discharged per unit time, the amount of drain generated during the accumulated time of the full load operation of the air compressor, and 1 of the drain discharge valve 5 Calculating the drain discharge amount associated with the opening and closing operations of the first time, and obtaining an operation pattern of the drain discharge valve for matching the drain generation amount and the drain discharge amount,
The operation of the drain discharge valve 5 is controlled according to the obtained operation pattern (Claim 1).

In the drain discharge method having the above-described configuration, the drain discharge amount associated with each opening / closing operation of the drain discharge valve 5 is quantified by setting the open time of the drain discharge valve 5 as a predetermined constant open time.
Based on the correspondence relationship, the accumulated time of the full load operation for generating the drain corresponding to or corresponding to the quantified drain discharge amount at the measured temperature or temperature and humidity is calculated,
The full load operation time of the air compressor 1 is measured, and the drain discharge valve 5 can be opened and closed once each time the accumulated time reaches the calculated accumulated time. (Claim 2).

As another method, the opening and closing operation of the drain discharge valve 5 is performed every time the full load operation of the air compressor reaches a set integration time of a predetermined time,
Based on the correspondence relationship, the drain discharge valve 5 opening time corresponding to or corresponding to the amount of drain generated when the air compressor is fully loaded at the set integrated time at the measured temperature or temperature and humidity. And the drain discharge valve 5 may be controlled to open and close during the calculated opening time (Claim 3).

The drain discharge mechanism of the air compressor 1 according to the present invention includes a cooling means 22 for cooling the compressed air discharged from the compressor main body 10 before supplying it to the consumer side, and the drain discharge valve 5 is repeatedly opened and closed. In the air compressor 1 for discharging the drain generated by the cooling means 22,
A sensor (7 and / or 8) for measuring the intake air temperature or temperature and humidity of the compressor body 10;
Control means 30 for controlling the opening / closing operation of the drain discharge valve 5 according to the detection signal of the sensor (7 and / or 8);
The control means 30 is
A measuring unit 33 for integrating the full load operation time of the air compressor 1;
Correspondence relationship between changes in temperature or temperature and humidity of intake air and changes in the amount of drain generated per unit time in the full load operation of the air compressor 1, and the amount of drain discharged per unit time of the drain discharge valve 5 A storage unit 32 for storing a relational expression that prescribes an operation pattern of the drain discharge valve 5 obtained in advance,
Based on the temperature or temperature and humidity of the intake air detected by the sensor (7 and / or 8) and the relational expression stored in the storage unit 32, the accumulated time of the full load operation of the air compressor 1 An operation processing unit 34 for specifying an operation pattern of the drain discharge valve that matches a generated amount of drain generated in step 1 and a drain discharge amount associated with one opening / closing operation of the drain discharge valve 5;
An operation control unit 35 that controls the operation of the drain discharge valve 5 according to the operation pattern specified by the arithmetic processing unit 34 is provided (Claim 4).

In the drain discharge mechanism having the above-described configuration, the storage unit 32 stores the opening time of the drain discharge valve 5 set for a fixed time as a set opening time, and the relational expression is a change in temperature or temperature and humidity. , Storing a relational expression defining a correspondence relationship with a change in the accumulated time of full load operation for generating drain corresponding to the drain discharge amount specified by the set release time;
Based on the temperature or temperature and humidity of the intake air detected by the sensor (7 and / or 8) and the relational expression stored in the storage unit 32, the arithmetic processing unit 34 calculates the set release time. Calculating the accumulated time of the full load operation for generating a drain that matches or corresponds to the specified drain discharge amount;
The operation control unit 35 can be configured to open and close the drain discharge valve 5 each time the measurement unit 33 measures the accumulated time of the full load operation calculated by the arithmetic processing unit 34 (claim). Item 5).

Further, as another configuration of the drain discharge mechanism, the storage unit 32 stores a set integration time which is an integration time of a full load operation set in advance as a predetermined time, and the temperature or temperature And a relational expression defining a correspondence relationship between the change in humidity and the change in the open time of the drain discharge valve 5 corresponding to the amount of drain generated in the full load operation of the set integration time,
Based on the temperature or temperature and humidity of the intake air detected by the sensor (7 and / or 8) and the relational expression stored in the storage unit 32, the arithmetic processing unit 34 determines the drain discharge valve 5 And calculating the opening time of
The operation control unit 35 is configured to control the opening and closing of the drain discharge valve according to the opening time calculated by the arithmetic processing unit 34 every time the measurement unit 33 measures a full load operation for the set integration time. (Claim 6).

  The control device 30 further receives a detection signal from the pressure sensor 6 for detecting the pressure of the compressed air supplied to the consumption side, and receives an intake valve 40 provided at the intake port 11 of the compressor body 10. A capacity control unit 31 is provided for controlling the opening / closing operation of the engine, and the measurement unit 33 receives the opening signal of the intake valve 40 from the capacity control unit 31 and measures the full load operation time of the air compressor. It can also be configured (claim 7).

  With the configuration of the present invention described above, according to the drain discharge method and drain discharge mechanism of the air compressor 1 of the present invention, the following remarkable effects can be obtained.

  The correspondence between the change in the temperature of the intake air and the change in the amount of drain generated per unit time in the full load operation of the air compressor 1 and the drain discharge amount per unit time of the drain discharge valve 1 are obtained in advance. From the measured intake air temperature, the accumulated time of full load operation, the amount of drain generated per unit time, and the amount of drain discharged per unit time based on a relational expression based on this correspondence, the air compression Calculate the amount of drain generated during the accumulated time of full load operation of the machine and the amount of drain discharged with one open / close operation of the drain discharge valve 5, and match the amount of drain generated and the amount of drain discharged. Since the opening / closing control of each time of the drain discharge valve 5 is performed based on the operation pattern of the drain discharge valve 5, the drain generation required in this way is performed. Is not a change in only the intake air amount of the compressor body 1, it was possible to reflect the change in the drain generation amount based on a change in the temperature of the intake air.

  As a result, the actual drain generation amount coincides with the drain discharge amount performed by one opening / closing operation of the drain discharge valve 5, so that the drain is introduced to the consumption side or the compressed air is discharged when the drain is discharged. Generation | occurrence | production of the pressure fall of the receiver tank 70, etc. by discharge | released was able to be prevented suitably.

  In particular, when control is performed in consideration of both the temperature and humidity as well as the temperature of the intake air, the amount of drain generated and the amount of discharge can be matched with extremely high accuracy, and the introduction of drain to the consumer side is possible. In addition, unnecessary discharge of compressed air was almost completely prevented.

  Such drain discharge is performed by setting the open time of the drain discharge valve 5 to be a constant time, and by changing the operation interval of the drain discharge valve 5 based on the correspondence relationship, or by operating the drain discharge valve 5. By making the interval constant and making the opening time of the drain discharge valve 5 variable, it was possible to relatively easily perform control to match the amount of drain generated and the amount of drain discharged.

  When the capacity control unit 31 for controlling the opening and closing of the suction valve 40 of the compressor body 10 is provided in the control device 30 that realizes the drain discharge mechanism, the product time of the full load operation of the air compressor 1 is counted. The measuring unit 33 that counts the operation of the capacity control unit 31, for example, the output time of a control signal for controlling the opening and closing of the intake valve 40, makes it possible to easily calculate the total load operation time of the air compressor 1. There are advantages such as being able to count.

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

[Example 1]
Overall Structure An example of an oil-cooled screw compressor 1 equipped with a drain discharge device according to the present invention will be described with reference to FIG. 1. This oil-cooled screw compressor 1 is composed of a housing 3 such as a soundproof box. The compressor body 10 is an oil-cooled screw compressor that compresses air together with lubricating oil in the housing 3, the motor 60 that drives the compressor body 10, and the compression A receiver tank 70 for introducing compressed air discharged together with the lubricating oil from the machine body 10 and separating the compressed air and the lubricating oil is provided.

  The intake port 11 of the compressor body 10 is provided with an intake valve 40 for controlling opening and closing of the intake port 11 of the compressor body 10 and an air filter 41 attached to the primary side of the intake valve 40. , A suction control circuit 84 that communicates between the closed pressure receiving chamber of the suction valve 40 and the receiver tank 70 is provided, so that the pressure in the receiver tank 70 can be introduced into the suction valve 40 as an operating pressure. 84, the suction valve control electromagnetic valve 4 is provided, and the operation of the suction valve 40 can be controlled by opening and closing the suction valve control electromagnetic valve 4.

  The above-described receiver tank 70 is communicated with the discharge port 12 of the compressor body 10, and the compressed air discharged together with the lubricating oil from the compressor body 10 is introduced into the receiver tank 70.

  The compressed air separated from the lubricating oil in the receiver tank 70 is supplied to a consumer side (not shown) via a supply circuit 81 communicated with the receiver tank 70 via a check valve 50, and the receiver tank 70 The lubricating oil recovered at 70 is configured to be supplied to the oil supply port 13 of the compressor body 10 via the oil supply circuit 82.

  The oil supply circuit 82 is provided with an oil cooler 21 that cools the lubricating oil. The lubricating oil cooled through the oil cooler 21 is again introduced into the compression working space, and the compressor body 10 Used for sealing of lubrication, cooling and compression working space.

  In the supply circuit 81 for supplying the compressed air in the receiver tank 70 to the consumer side, cooling means for compressed air such as the aftercooler 22 and the dryer 23 is provided.

  A drain discharge valve 5 that is an electromagnetic valve is provided in a drain discharge circuit 83 branched from the supply circuit 81 through the dryer 23, and the drain accumulated in the dryer 23 by opening and closing the drain discharge valve 5. It is configured to control the start and stop of discharge.

  The supply circuit 81 is further provided with a pressure sensor 6 for detecting the pressure in the supply circuit 81, that is, the pressure of the compressed air supplied to the consumption side. In the illustrated embodiment, the pressure sensor 6 is described above. Is provided in the supply circuit 81 between the aftercooler 22 and the check valve 50.

  In FIG. 1, reference numeral 3 a denotes an intake port for introducing outside air into the housing 3. An outside air temperature sensor 7, which is a temperature sensor, is provided at a position where the intake port 3 a is formed, and the outside air introduced into the housing 3. It is comprised so that the temperature of can be measured.

  The outside air temperature sensor 7 may be provided at any position in the air flow path from the intake port 3a to the intake port 11 of the compressor body 10.

  Further, in FIG. 1, reference numeral 30 denotes a control device. The control device 30 receives the outside air temperature detected by the outside air temperature sensor 7 and the pressure detected by the pressure sensor 6 and receives a preset program. In accordance with the above, the electronic control device outputs a control signal to the suction valve control solenoid valve 4 and the drain discharge valve 5, and according to the detection signals of the sensors 6 and 7, the suction valve control solenoid valve 4 and the drain discharge By controlling the valve 5 as follows, capacity control and drain discharge control are performed.

Based on the detection signal received from the pressure sensor 6, the capacity control control device 30 controls the intake valve control electromagnetic valve 4 as follows, thereby changing the operating state of the air compressor 1 to the compressor body 10. Capacity control is performed to switch between unload operation with the intake port 11 closed and full load operation with the intake port 11 of the compressor body 10 opened.

  Such capacity control is performed by a capacity control unit 31 (see FIG. 2) that is realized by executing a program stored in advance in the control device 30. The capacity control unit 31 sets the detection value of the pressure sensor in advance. In a state where the unload start pressure (for example, 0.7 MPa) has not been reached, the suction valve control electromagnetic valve 4 is closed by outputting a control signal or stopping the output.

  Thus, the compressed air in the receiver tank 70 is not introduced into the closed pressure receiving chamber of the intake valve 40, the intake valve 40 is opened, and the compressor body 10 is in full load operation.

  On the other hand, when it is determined from the detection signal of the pressure sensor 6 that the secondary side pressure of the check valve 50 has reached the unload start pressure, the control device 30 outputs the control signal or stops the suction valve control electromagnetic by the output stop. The valve 4 is opened.

  Thus, the compressed air in the receiver tank 70 is introduced into the closed pressure receiving chamber of the suction valve 40, the suction valve 40 is closed, the compressor body 10 shifts to the unload operation, and the detected value of the pressure sensor 6 is detected. Until the full load starting pressure (for example, 0.6 MPa) is reduced, the open state of the intake valve control solenoid valve 4 is maintained. As a result, the suction valve 40 is kept closed, and the compressor body 10 continues the unload operation.

  On the other hand, the pressure in the receiver tank 70 decreases due to the consumption of compressed air on the consumption side, and the secondary pressure of the check valve detected by the pressure sensor 6 decreases below the full load start pressure (for example, 0.6 MPa). Then, the capacity control unit 31 of the control device 30 closes the intake valve control electromagnetic valve 4, whereby the intake valve 40 is opened, and the compressor body 10 shifts to the full load operation, and the receiver tank The pressure in 70 is increased.

  By repeating such an operation, the capacity control unit 31 of the control device 30 performs capacity control so that the pressure of the compressed air supplied to the consumption side is always within a certain range.

  In the above example, the suction valve 40 is a closed pressure receiving type, and the suction valve control solenoid valve 4 is provided in the suction control circuit 84 that communicates between the receiver tank 70 and the closed pressure receiving chamber of the suction valve 40. However, for example, when the intake valve 40 itself can be controlled to open and close by the input of an electric signal, the intake valve control electromagnetic valve 4 is controlled by the control device 30. The valve 40 may be configured such that the capacity control unit 31 of the control device 30 directly controls opening and closing, and the configuration for realizing the capacity control is not limited to the configuration shown in FIG.

Drain discharge control The control device 30 described above has a configuration that enables drain discharge control performed by opening and closing the drain discharge valve 5 in addition to the capacity control described above.

  In order to enable such drain discharge control, the control device 30 described above is realized by executing a storage unit 32 and a program stored in advance in the storage unit 32 as shown in FIG. A measurement unit 33, an arithmetic processing unit 34, and an operation control unit 35 that controls the operation of the drain discharge valve 5 are provided.

  Of these, the storage unit 32 stores an operation program and a relational expression for obtaining a change in the operation timing of the drain discharge valve 5 in response to a change in the outside air temperature detected by the outside air temperature sensor 7. ing.

  This relational expression is obtained by measuring, for example, the temperature of the intake air in the air compressor 1 that is the target of the drain discharge control method according to the present invention, and changing the temperature of the intake air introduced into the compressor body 10. And the change in the amount of drain generated in the cooling means 22 by the full load operation per unit time of the air compressor 1 is obtained, and the drain discharge amount per unit time of the drain discharge valve 5 is measured by actual measurement. When the temperature of the intake air is determined based on these actually measured values, the one that can calculate the operation pattern of the drain discharge valve that can match the drain generation amount and the drain discharge amount is stored.

  As an example, as shown in FIG. 4, the opening time in one opening / closing operation of the drain discharge valve 5 is set to a predetermined time (set opening time) y, and drain discharge accompanying one opening / closing operation of the drain discharging valve is performed. In the present embodiment in which the amount is quantified, and the drain discharge valve 5 is opened / closed for each integration time of the full load operation that becomes the drain generation amount corresponding to the quantified drain discharge amount, FIG. As shown in Fig. 4, as the outside air temperature increases, the accumulated time of the full load operation (that is, the operation interval of the drain discharge valve 5) at which the drain generation amount corresponding to the quantified drain discharge amount decreases, and conversely the outside air temperature. When the value becomes lower, the accumulated time (and hence the operation interval of the drain discharge valve 5) increases.

  When the temperature of the intake air is specified based on such a correspondence relationship, the accumulated times x1 and x2 of the full load operation necessary for obtaining the drain generation amount corresponding to the quantified drain discharge amount are obtained. The relational expression is memorized.

  The above-described measuring unit 33 integrates and counts the full load operation time of the air compressor 1 and is configured by a known timer or the like.

  In the present embodiment in which the control device 30 includes the capacity control unit 31 described above, for example, the measurement unit 33 is operated by the capacity control unit 31 during the operation of the air compressor 1. Is counted in the full load operation state in which the engine is opened (the time in the unload operation state in which the intake port 11 is closed is removed from the count). In the embodiment shown in FIG. 1, when the intake valve 40 is a pressure-receiving closed valve type intake valve and the intake valve control solenoid valve 4 is normally open (normally open) type, the control device 30 The capacity control unit 31 of the compressor integrates and counts the time during which the control signal is output (application of the operating voltage) to the intake valve control solenoid valve 4, so that the full load operation of the air compressor can be easily performed. During integration It can be carried out of the count.

  The arithmetic processing unit 34 is configured to perform the set opening time y based on the relational expression stored in the storage unit 32 according to the outside air temperature detected by the outside air temperature sensor 7 provided in the air inlet 3a of the air compressor 1. The accumulated times x1 and x2 of the full load operation for generating drain corresponding to the drain discharge amount are calculated.

  The above-described operation control unit 35 controls the opening / closing operation of the drain discharge valve 5, and the total processing time of the full load operation counted by the above-described measurement unit 33 is calculated by the arithmetic processing unit 34 based on the relational expression. When the accumulated time is reached, the drain discharge valve 5 is opened and closed once according to the set opening time y.

  When the opening / closing operation of the drain discharge valve 5 is completed once, the above-described measuring unit 33 resets the count, and again starts to accumulate the full load operation time of the air compressor 1, and each unit performs the above-described operation. Repeatedly, the drain discharge valve 5 is controlled to open and close with a predetermined operation pattern (integrated time x1, x2) according to a predetermined correspondence specified by the relational expression, and the drain is discharged intermittently.

  As a result, when the outside air temperature decreases for some reason during the operation of the air compressor, the operation control unit 35 initially counts the accumulated time x1 of the full load operation as shown in FIG. The drain opening valve is opened and closed once when the extended accumulated time x2 is counted, and the operation interval of the drain discharging valve 5 is made variable.

Operation and Action When the air compressor 1 having the drain discharge mechanism configured as described above is operated, outside air is taken into the machine from the intake port 3a of the housing 3, and the compressor body 10 sucks the air inside the machine and compresses it. To do.

  The compressed air discharged from the compressor body 10 separates the lubricating oil contained in the receiver tank 70 and the separator 71. Then, after cooling by the aftercooler 22 and the dryer 23 as cooling means, water vapor in the compressed air condenses to generate drain, and the drain generated in the aftercooler 22 is sent to the dryer 23 together with the compressed air, and the drain of the dryer 23 is drained. It is temporarily stored in the storage part.

  The drain stored in the drain storage portion of the dryer 23 is discharged through a drain discharge circuit 83 including a drain discharge valve 5 that is controlled to open and close based on an open / close signal from the control device 30.

  The capacity control unit 31 of the control device 30 outputs an opening / closing signal for the electromagnetic valve 4 for intake valve control based on the pressure of the compressed air detected by the pressure sensor 6 provided in the supply circuit 81 as described above.

  In response to the output of the close signal to the intake valve control electromagnetic valve 4, the measurement unit 33 starts counting the open time of the intake valve 40, that is, the full load operation time of the air compressor 1.

  The operation control unit 35 that controls the operation of the drain discharge valve opens the signal to the drain discharge valve 5 when the count of the full load operation time by the measurement unit 33 reaches the accumulated time calculated by the arithmetic processing unit 34. Is output, the drain discharge valve 5 is opened at a predetermined time y, and then the drain discharge valve 5 is closed.

  At this time, the accumulated time calculated by the arithmetic processing unit 34 is obtained based on the outside air temperature detected by the outside air temperature sensor 7 provided in the vicinity of the intake port and the relational expression stored in the storage unit 32. The accumulated time x1, x2,... For defining the operation interval from one opening / closing operation of the discharge valve 5 to the next opening / closing operation is based on the change of the outside air temperature as shown in FIG. The drain generation amount generated by the full load operation and the drain discharge amount discharged by one opening / closing of the drain discharge valve 5 are adjusted to coincide with each other.

  In this way, the timer adds up the full load operation time and does not add up the unload time during which no outside air is sucked into the compressor body. Therefore, the drain discharge valve is set according to the amount of drain generated corresponding to the intake air amount of the compressor. Not only the operation interval is determined, but also the operation interval of the drain discharge valve is determined according to the amount of drain generated corresponding to the change in the outside air temperature.

  Here, the only problem with temperature is that even if the temperature is the same, the amount of drain generated changes due to changes in humidity. Because it is.

  As a result, the amount of drain generated from one operation of the drain discharge valve 5 to the next operation coincides with the amount of drain discharge by one opening / closing operation of the drain discharge valve 5, and the compressed air is discharged together with the drain. It is possible to suppress waste discharged to the outside and to prevent the compressed air mixed with drain from being supplied to the pneumatic equipment on the consumption side.

  In addition, the control device 30 receives the detection signal from the pressure sensor 6 and controls the intake valve control electromagnetic valve 4 to open and close, thereby controlling the operation state of the air compressor 1 to unload operation or full load operation. Since the control device 30 has a function as a control device, the control device 30 determines whether the operation state of the air compressor 1 is an unload operation or a full load operation by outputting an opening / closing signal to the electromagnetic valve 4 for suction valve control. It can be easily grasped in which state.

  Therefore, the measurement unit 33 of the control device 30 interrupts the count by the open signal to the intake valve control electromagnetic valve 4 and restarts the count by the close signal, and also counts by the open signal to the drain discharge valve 5. By resetting, it is possible to easily count the total time of full load operation.

  In the above embodiment, the full load operation time from the end of the open / close operation of the drain discharge valve 5 to the start of the next open / close operation is integrated. However, the present invention is not limited to this, and the drain discharge valve 5 is opened. The full load operation time may be accumulated even when the vehicle is running. When the full load operation time reaches a predetermined time, the drain discharge valve 5 is opened and the accumulation time is reset to accumulate the full load operation time. be able to.

[Example 2]
In the configuration described in the first embodiment described above, the control device 30 performs control so that the open time of the drain discharge valve 5 is a fixed time and the operation interval of the drain discharge valve 5 is variable according to changes in the outside air temperature. However, instead of this configuration, as shown in FIG. 6, the control device 30 causes the drain discharge valve 5 to be opened and closed at regular intervals x. It may be configured to be variable as y1, y2, y3,.

  That is, if the opening time of the drain discharge valve 5 is lengthened, the amount of drained water increases during this period, while if the opening time of the drain discharge valve 5 is shortened, the amount of drainage discharged during this time decreases. Therefore, if the amount of drain generated by a full load operation for a certain time changes according to the change in the outside air temperature, the drain generation amount and the drain discharge amount are matched by changing the opening time of the drain discharge valve 5 I try to let them.

  In order to perform such drain discharge, in this embodiment, the accumulated time of unloading operation of the air compressor 1 that predefines the operation interval of the drain discharge valve 5 in the storage unit 32 of the control device 30. x is stored as the set integration time.

  And in order to calculate the change of open time y1, y2, y3, ... of the drain discharge valve 5 accompanying the change of external temperature in the memory | storage part 32 of the control apparatus 30, change of external temperature and this external temperature are calculated. The correspondence relationship of the change in the opening time of the drain discharge valve corresponding to the change in is stored as a relational expression.

  As described above, due to the difference in the relational expression stored in the storage unit 32, the arithmetic processing unit 34 is based on the outside air temperature detected by the outside air temperature sensor 7, and the drain generated by the full load operation for the set integration time at the outside air temperature. The open times y1, y2, y3,... Of the drain discharge valve 5 for generating the drain discharge amount corresponding to the generated amount are calculated.

  The operation control unit 35 performs one-time opening / closing control of the drain discharge valve 5 every time the total count of the full load operation by the measurement unit 33 reaches the set integration time x stored in the storage unit 32 in advance. At the time of this opening / closing, the opening / closing time of the drain discharge valve 5 is opened by the opening times y1, y2, y3,.

  With the subsequent closing operation of the drain discharge valve 5, the count by the measuring unit 33 is reset, the counting of the accumulated time of full load operation is started again, and when the accumulated time reaches the set time x, the drain discharging valve 5 is removed. The operation of releasing the drain after opening for a time calculated based on the temperature is repeated.

  For example, as shown in FIG. 5, when the outside air temperature is high, the open time of the drain discharge valve 5 becomes long and the outside air temperature is low. In this case, the opening time of the drain discharge valve 5 is shortened.

  As an example, when the outside air temperature rises for some reason after opening / closing operation of the drain discharge valve 5 at the opening time y1, the control device changes the opening time of the drain discharge valve 5 as shown in FIG. The opening time of the discharge valve 5 is increased to y2.

  On the contrary, when the outside air temperature decreases after the opening / closing operation at the opening time y2, the drain generation time is reduced by decreasing the drain discharge amount by reducing the opening time of the drain discharge valve 5 to y3. Match the amount and drain discharge.

  As described above, the drain discharge valve 5 is shortened for the time required to discharge the generated drain by shortening the opening time of the drain discharge valve 5 in accordance with the decrease in the amount of drain generated as the outside air temperature decreases. Compressed air can be prevented from being discharged after draining without being opened, and useless power can be prevented from being consumed due to the shift to full load operation due to pressure drop. .

  On the other hand, if the amount of drain generated due to an increase in outside air temperature increases, the open time of the drain discharge valve increases corresponding to this increase, so that the remaining drain without being discharged is accumulated. Thus, it can be suitably prevented from being introduced to the consumption side together with the compressed air.

Example 3
In the first and second embodiments described above, the control device 30 makes the operation intervals x1 and x2 of the drain discharge valve 5 variable based on the outside air temperature sensor 7 provided at the intake port 3a (the first embodiment; see FIG. 4), or Although the opening times y1, y2 and y3 of the drain discharge valve 5 are variable (Example 2; see FIG. 6), instead of measuring the outside air temperature (intake air temperature), the humidity of the intake air is measured. The same control as described above may be performed. In this case, a humidity sensor is provided in place of the outside air temperature sensor 7 in the apparatus configuration shown in FIG.

  More preferably, as shown in FIG. 7, in addition to the outside air temperature sensor 7, a humidity sensor 8 is provided facing the intake air flow path, in the illustrated example, the air inlet 3 a, and the outside air detected by the outside air temperature sensor 7 is provided. Based on both the temperature and the humidity of the intake air detected by the humidity sensor 8, the control device 30 is configured to vary the operation interval of the drain discharge valve 5 or the opening time of the drain discharge valve 5.

  In order to realize such a drain discharge method, the storage means 32 of the control device 30 stores the operation interval of the drain discharge valve 5 or the opening time of the drain discharge valve 5 which is optimum at the measured outside air temperature and humidity. A relational expression for calculation is stored.

  In the drain discharge mechanism configured as described above, not only changes in the amount of drain generated due to changes in the outside air temperature, but also changes in the amount of drain generated based on changes in the humidity of the outside air sucked into the compressor body are considered. Since the operation interval of the drain discharge valve 5 or the opening time of the drain discharge valve 5 is variable, the operation interval of the drain discharge valve 5 so as to obtain a drain discharge amount corresponding to the drain generation amount with higher accuracy. Alternatively, the drain discharge valve 5 can be controlled to open and close during the opening time, drain is introduced to the consumption side due to insufficient drain discharge, or the drain discharge valve 5 is opened excessively with respect to the amount of drain generated. The release of compressed air due to is preferably prevented.

[Others]
In the above-described embodiments described with reference to FIGS. 1 and 6, a dryer 23 is provided on the secondary side of the aftercooler 22, and a drain discharge circuit 83 communicated with the drain storage portion of the dryer 23 is provided. The drain is discharged via the drain 23, but instead of the dryer 23, a drain separator 23 'for separating compressed air and drain is provided on the secondary side of the aftercooler 22, as shown in FIG. You may comprise so that the drain discharge circuit 83 may be connected to the lower end of the drain storage part provided in 23 '.

  As for other configurations, any of the configurations of the first to third embodiments described with reference to FIGS. 1 and 7 described above can be employed.

Explanatory drawing of the air compressor provided with the drain discharge mechanism of this invention. The functional block diagram of a control apparatus. The correlation diagram which shows the change of the change of the outside temperature, and the change of the operation interval of a drain discharge valve. The time chart which shows operation | movement of a drain discharge valve. The correlation diagram which shows the change of the open temperature of a drain discharge valve, and the change of external temperature. The time chart which shows operation | movement of a drain discharge valve. Explanatory drawing of the air compressor provided with another drain discharge mechanism of this invention. Explanatory drawing of the air compressor provided with the drain discharge mechanism of this invention.

Explanation of symbols

1 Air compressor (oil-cooled screw compressor)
DESCRIPTION OF SYMBOLS 3 Housing | casing 3a Intake port 4 Solenoid valve for intake valve control 5 Drain discharge valve 6 Pressure sensor 7 Outside temperature sensor 8 Humidity sensor 10 Compressor body 11 Intake port 12 Discharge port 13 Oil supply port 21 Oil cooler 22 Cooling means (after cooler)
23 Cooling means (dryer)
23 'Collection means (drain separator)
DESCRIPTION OF SYMBOLS 30 Control apparatus 31 Capacity | capacitance control part 32 Memory | storage part 33 Measurement part 34 Operation processing part 35 Operation control part 40 Suction valve 41 Air filter 50 Check valve 60 Motor 70 Receiver tank 71 Separator 81 Supply circuit 82 Oil supply circuit 83 Drain discharge circuit 84 Suction Control circuit

Claims (7)

Drain discharge of an air compressor having cooling means for cooling before supplying compressed air discharged from the compressor body to the consuming side, and discharging drain generated by the cooling means by repeatedly opening and closing the drain discharge valve In the method,
Corresponding relationship between changes in intake air temperature or temperature and humidity and changes in drain generation per unit time in full load operation of the air compressor, and drain discharge per unit time of the drain discharge valve are obtained in advance. And
Measure the temperature or temperature and humidity of the intake air, measure and accumulate the full load operation time of the air compressor, and based on the correspondence, the measured temperature or temperature and humidity and the full load operation From the accumulated time, the amount of drain generated per unit time and the amount of drain discharged per unit time, the amount of drain generated during the accumulated time of the full load operation of the air compressor and the one time of the drain discharge valve Calculating a drain discharge amount associated with the opening / closing operation of the valve, and obtaining an operation pattern of the drain discharge valve for matching the drain generation amount and the drain discharge amount,
A drain discharge method in an air compressor, wherein the operation of the drain discharge valve is controlled according to the obtained operation pattern. Quantifying the drain discharge amount associated with each opening and closing operation of the drain discharge valve, with the opening time of the drain discharge valve as a predetermined constant opening time,
Based on the correspondence, calculate an accumulated time of full load operation for generating drain that matches the quantified drain discharge at the measured temperature or temperature and humidity;
2. The full load operation time of the air compressor is measured, and the drain discharge valve is caused to perform one opening / closing operation every time the accumulated time reaches the calculated accumulated time. The air compressor drain discharge method described. The opening and closing operation of the drain discharge valve is performed every time the full load operation of the air compressor reaches a predetermined set integration time,
Based on the correspondence relationship, the drain discharge valve opening time corresponding to the amount of drain generated when the air compressor is fully loaded at the set integration time at the measured temperature or temperature and humidity is calculated. The drain discharge method for an air compressor according to claim 1, wherein the drain discharge valve is controlled to open and close during the calculated opening time. An air compressor comprising cooling means for cooling before supplying compressed air discharged from a compressor body to a consumer side, and discharging drain generated by the cooling means by a drain discharge valve that repeatedly opens and closes.
A sensor for measuring the intake air temperature or temperature and humidity of the compressor body;
Control means for controlling the opening and closing operation of the drain discharge valve according to the detection signal of the sensor;
The control means is
A measuring unit for measuring and integrating the full load operation time of the air compressor;
Based on the relationship between the change in temperature or temperature and humidity of intake air and the change in the amount of drain generated per unit time in full load operation of the air compressor, and the amount of drain discharged per unit time of the drain discharge valve A storage unit for storing a relational expression that prescribes the operation timing of the drain discharge valve obtained in advance;
Based on the temperature or temperature and humidity of the intake air detected by the sensor and the relational expression stored in the storage means, the amount of drain generated during the accumulated time of full load operation of the air compressor, An arithmetic processing unit for specifying an operation pattern of the drain discharge valve that matches a drain discharge amount associated with one opening / closing operation of the drain discharge valve;
A drain discharge mechanism in an air compressor, comprising: an operation control unit that controls the operation of the drain discharge valve in accordance with an operation pattern specified by the arithmetic processing unit. The storage unit stores the opening time of the drain discharge valve set for a fixed time as a set opening time, and as a relational expression, the drain specified by the change in temperature or temperature and humidity and the set opening time. Stores a relational expression that defines the correspondence with the change in the accumulated time of full load operation that generates drain corresponding to the discharge amount,
The arithmetic processing unit matches the drain discharge amount specified by the set open time based on the temperature or temperature and humidity of the intake air detected by the sensor and the relational expression stored in the storage unit. Calculate the accumulated time of the full load operation that generates drain,
5. The drain discharge mechanism according to claim 4, wherein the operation control unit opens and closes the drain discharge valve every time the measurement unit measures the accumulated time of the full load operation calculated by the arithmetic processing unit. . The storage unit stores a set integration time that is an integration time of a full load operation set in advance for a fixed time, and as a relational expression, a change in temperature or temperature and humidity, and a full load operation of the set integration time. Storing a relational expression that defines the correspondence with the change in the open time of the drain discharge valve that matches the amount of drain generated in
The arithmetic processing unit calculates the opening time of the drain discharge valve based on the temperature or temperature and humidity of the intake air detected by the sensor and the relational expression stored in the storage unit;
5. The open / close control of the drain discharge valve according to the open time calculated by the arithmetic processing unit whenever the measuring unit measures a full load operation for the set integration time. The drain discharge mechanism as described. The control device receives a detection signal from a pressure sensor that detects a pressure of compressed air supplied to a consumer side, and controls an opening / closing operation of an intake valve provided in an intake port of the compressor body. Further comprising
The air compressor according to any one of claims 4 to 6, wherein the measuring unit receives the opening signal of the intake valve from the capacity control unit and measures a full load operation time of the air compressor. Drain discharge mechanism.

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