WO2023032573A1

WO2023032573A1 - Oil feeding type compressor

Info

Publication number: WO2023032573A1
Application number: PCT/JP2022/029770
Authority: WO
Inventors: 知之角; 健太郎山本
Original assignee: 株式会社日立産機システム
Priority date: 2021-08-30
Filing date: 2022-08-03
Publication date: 2023-03-09
Also published as: JP2023034306A; CN117677769A

Abstract

This oil feeding type compressor is provided with: a compressor body (2) that compresses gas while pouring oil; a first oil separator (6) that separates oil from the compressed gas that has been ejected from the compressor body (2); a second oil separator (8) that further separates oil from the compressed gas from which the oil has been separated by the first oil separator (6), and that has a storage unit (8bd) to store the separated oil; an ejection pipe system (9) through which the compressed gas from which the oil has been separated by the second oil separator (8) flows; an oil discharging path (10) that discharges the oil stored in the storage unit (8bd) from the storage unit (8bd); a valve body (10a) that is provided in the oil discharging path (10); and a control unit (11) that controls the degree of opening of the valve body (10a) on the basis of time.

Description

Lubricated compressor

The present invention relates to an oil-fed compressor.

In the oil-fed compressor, the air that is sucked from the intake side of the compressor body by driving the compressor body is mixed with lubricating oil and compressed to a predetermined pressure. Oil is separated (primary separation) from the compressed gas-liquid mixed compressed air in the oil separator (first oil separator), and the oil content is further separated (secondary separation) in the oil separation element (second oil separator). ), and then flowed through a cooler or the like to the discharge channel.

In addition, the oil primarily separated by the first oil separator is collected in an oil tank provided below the first oil separator. The oil in the oil tank is pressure-fed to the intake side of the compressor body by the pressure of the compressed air in the oil tank, and is returned to the compressor body.

On the other hand, Patent Literature 1, for example, discloses an oil-fed compressor in which the oil that is secondarily separated by the second oil separator is returned to the compressor main body. In the oil-fed compressor of Patent Document 1, the pressure of the compressed air causes the oil that has descended to the element head provided below the second oil separator to flow through the oil recovery hole formed in the element head to the intake side of the compressor body. It is pumped and returned to the main body of the compressor.

JP 2003-120565 A

By the way, the oil recovered from such an oil recovery hole is discharged by the pressure of the compressed air in the second oil separator. There is also the possibility that some of the compressed air generated in the main body will be wasted, which is one of the factors that reduce compressor efficiency.

Here, in order to reduce the amount of compressed air discharged during oil recovery, the diameter of the return path for returning oil from the oil recovery hole to the compressor body is reduced, or an orifice that restricts the flow of oil is added to the return path. It is conceivable to provide (further reduce the orifice diameter, etc.). However, there is a concern that the piping will be clogged and recovery will be poor, and it can be said that there is a certain limit to reducing the diameter.

In particular, in small-sized oil-fed compressors, the amount of oil collected from the oil collection hole tends to be small due to the small amount of discharged air. is relatively large, and there is a possibility that deterioration in compressor performance cannot be improved.

In addition, when using a configuration that allows variable speed operation of the compressor body, for example, when an electric motor (electric motor) having a power converter (inverter) is used as a drive source for the compressor body, during low-load operation, the discharge Since the amount of air recovered from the oil recovery hole is small, the amount of compressed air discharged remains the same, and the performance of the compressor tends to decline.

This problem has been made in view of the above problems, and an oil-filled compressor that can suppress the amount of compressed air discharged when recovering the oil separated by the second oil separator and suppress the decrease in compression efficiency. intended to provide.

In order to achieve the above object, the present invention provides a compressor body for compressing gas while injecting oil, a first oil separator for separating oil from the compressed gas discharged from the compressor body, and the first oil separator. 1. A second oil separator that further separates oil from the compressed gas from which the oil has been separated by the oil separator and has a reservoir for storing the separated oil; A discharge piping system through which gas flows, an oil discharge path for discharging the oil stored in the reservoir from the reservoir, a valve body provided in the oil discharge path, and an opening degree of the valve body that is changed with time. and a control unit that controls based on the

Further, the present invention provides a compressor body for compressing gas while injecting oil, a first oil separator for separating oil from the compressed gas discharged from the compressor body, and a first oil separator for separating oil from the compressed gas. a second oil separator having a reservoir for further separating oil from the separated compressed gas and storing the separated oil; and a discharge piping system through which the compressed gas from which the oil is separated in the second oil separator flows an oil discharge path for discharging the oil stored in the reservoir from the reservoir; a valve body provided in the oil discharge path; and a control unit for controlling the degree of opening of the body.

Further, the present invention provides a compressor body for compressing gas while injecting oil, a first oil separator for separating oil from the compressed gas discharged from the compressor body, and a first oil separator for separating oil from the compressed gas. a second oil separator having a reservoir for further separating oil from the separated compressed gas and storing the separated oil; and a discharge piping system through which the compressed gas from which the oil is separated in the second oil separator flows an oil discharge path for discharging the oil stored in the reservoir from the reservoir; a valve element provided in the oil discharge path; a pressure sensor for detecting pressure in the discharge piping system; a control unit for controlling the degree of opening of the valve body based on time, wherein the control unit determines the timing of narrowing the degree of opening of the valve body based on the pressure detected by the pressure sensor during the opening of the valve body. Control.

According to the present invention, in an oil-fed compressor, it is possible to suppress the amount of compressed air discharged when collecting the oil separated by the second oil separator, thereby suppressing a decrease in compression efficiency.

1 is a schematic diagram showing the configuration of an oil-fed compressor according to first and third embodiments of the present invention; FIG. 4 is a time chart of valve body opening degree control by the control unit of the oil-fed compressor according to the first embodiment of the present invention. It is a schematic diagram showing the configuration of an oil-fed compressor according to second and third embodiments of the present invention. 8 is a graph showing changes in the load factor of the compressor main body over time, and a time chart of valve opening degree control by the control unit for the oil-fed compressor according to the second embodiment of the present invention. 8 is a graph showing a change over time in the pressure detected by the pressure sensor, and a time chart of the opening control of the valve body by the control unit, for the oil-fed compressor according to the third embodiment of the present invention. Regarding the oil-fed compressor according to the third embodiment of the present invention, a graph showing changes over time in the load factor of the compressor main body, a graph showing changes over time in the detected pressure of the pressure sensor, and a valve by the control unit 4 is a time chart of body opening degree control;

The configuration and operation of the oil-fed compressor according to the first to third embodiments of the present invention will be described below with reference to the drawings. In addition, in each figure, the same code|symbol shows the same part.

(First embodiment)
FIG. 1 is a schematic diagram showing the configuration of an oil-fed compressor 1A according to the first embodiment of the present invention. The oil-fed compressor 1A includes a compressor body 2, an electric motor 3, a suction filter 4, a suction valve 5, a first oil separator 6, an oil supply system 7, and a second oil separator (oil separator) 8. , a discharge piping system 9 , an oil discharge path 10 , and a control unit 11 .

The compressor main body 2 is a portion that generates compressed air, and includes a pair of

screw rotors

2a and 2b (only one of the pair is shown in FIG. 1) that meshes with each other, and a casing (not shown) that houses the pair of

screw rotors

2a and 2b. ). Compression chambers (not shown), which are closed spaces, are formed by the combination of the meshing of the pair of

screw rotors

2a and 2b and the casing.

The electric motor 3 uses the

screw rotors

2a and 2b of the compressor body 2 as a drive source. As the pair of

screw rotors

2a and 2b are driven by the electric motor 3, the compression chamber moves in the axial direction of the

screw rotors

2a and 2b (to the left in FIG. 1), performing the process of sucking, compressing, and discharging air. Do it continuously. Therefore, the compression chamber takes in air through the intake filter 4 and the intake valve 5 provided on the suction side of the compressor main body 2, compresses the air, and compresses the compressed air provided on the discharge side of the compressor main body 2. It is then discharged to the first oil separator 6 . In addition, oil is supplied to the compression chamber from an oil supply system 7 for purposes such as cooling heat generated when compressing air, sealing the compression chamber, and lubricating the

screw rotors

2a and 2b.

The first oil separator 6 is, for example, a swirl separation type gas-liquid separator that primarily separates oil from compressed air by centrifugal separation. not shown) are formed. The primarily separated oil is stored in an oil tank 6 a below the first oil separator 6 .

The oil supply system 7 is a pipe or the like that connects the oil tank 6a and the compressor main body 2, and the pressure difference between the compressed air in the first oil separator 6 and the air sucked into the compressor main body 2 causes the oil tank 6a to The oil stored in is injected into the compression chamber of the compressor main body 2 . One or more holes for injecting oil into the compression chamber are provided downstream of the oil supply system 7, and the oil is injected or sprayed into the compression chamber from the one or more holes. When the oil is injected from a plurality of holes, the oil injected from each of the plurality of holes may collide with each other to spray the oil.

The oil supply system 7 is provided with an oil cooler 7a that cools the oil, and an oil filter 7b that is arranged downstream of the oil cooler 7a and removes impurities in the oil. The oil cooler 7a cools the oil by heat exchange with the cooling air induced by the cooling fan 13 rotated by the fan motor 12 .

The oil separator 8 is for secondary separation of the mist-like oil contained in the compressed air from which the oil has been primarily separated. Primary separated compressed air is fed.

The oil separator 8 includes an element 8a which is a filter for filtering mist-like oil contained in the primarily separated compressed air, a head 8b having a recess (not shown) in which the lower part of the element 8a is fitted, and the element 8a. and a case 8c that covers the head 8b and is coupled to the head 8b.

The element 8a is, for example, a cylindrical filter made of non-woven fabric, mesh-structured metal, or a combination thereof, and having open top and bottom ends. there is

The head 8b causes the compressed air from which the oil is primarily separated to flow into one side (outer peripheral side in this embodiment) of the element 8a, and the compressed air from which the oil is secondarily separated by the element 8a flows into the other side of the element 8a. It is a component for ejecting from (in this embodiment, the inner peripheral side). The head 8b includes, for example, a recess into which the lower part of the element 8a is fitted, an introduction channel 8ba, a discharge pipe 8bb, an outlet channel 8bc, a reservoir 8bd, a discharge hole (not shown), and a discharge flow. A path 8be is provided.

The introduction flow path 8ba is a flow path that communicates with the first oil separator 6 and allows compressed air from which oil is primarily separated by the first oil separator 6 to flow into the element 8a. The discharge pipe 8bb is a pipe extending upward from the center of the head 8b and having an upper end opening located inside the element 8a mounted on the head 8b. The opening of the discharge pipe 8bb is preferably located near the upper end of the element 8a so that the secondary separated and dripped oil is not swept up by the compressed air stream and flows into the discharge piping system 9.

The outlet flow path 8bc is a flow path that communicates with the discharge pipe 8bb and the discharge piping system 9. The compressed air from which the oil is secondarily separated by the element 8a is discharged to the discharge piping system 9 via the discharge pipe 8bb and the outlet flow path 8bc.

The storage portion 8bd is a portion that stores oil that is filtered and separated from the compressed air by the element 8a and that drips onto the element 8a. It is formed around the discharge pipe 8bb by the outer peripheral wall. There is a possibility that the oil stored in the storage portion 8bd is swept up by the stream of compressed air that has passed through the element 8a, and is discharged together with the compressed air from the opening of the discharge pipe 8bb. For this reason, in the storage portion 8bd, for example, a cylindrical shielding plate (Fig. not shown) are provided.

The discharge hole is a hole provided in the lower part (bottom part in this embodiment) of the storage part 8bd, and communicates with the discharge channel 8be. The discharge passage 8be is a passage that communicates the reservoir 8bd and the oil discharge passage 10 via a discharge hole. send out.

The case 8c is a cylinder having a top plate and an open lower end, which covers the element 8a and whose lower end is connected to the head 8b. The joint between the head 8b and the case 8c is sealed so as to prevent leakage of compressed air and oil.

The discharge piping system 9 is a piping or the like that is connected to the outlet flow path 8bc of the oil separator 8 and discharges the compressed air from which the oil is secondarily separated by the oil separator 8 to the user side. The discharge piping system 9 includes a check valve 9a located downstream of the oil separator 8, a pressure sensor 9b located between the oil separator 8 and the check valve 9a, and a pressure sensor 9b located downstream of the check valve 9a. An aftercooler 9c is provided for cooling the compressed air.

The check valve 9a prevents backflow of compressed air from the user side to the oil separator 8. Pressure sensor 9 b detects the pressure of the compressed air discharged from oil separator 8 . The aftercooler 9c cools the compressed air by heat exchange with the cooling air induced by the cooling fan 13. Therefore, the user is supplied with cooled compressed air.

The oil discharge path 10 is a pipe or the like that connects the reservoir 8bd and the compressor body 2 via the discharge flow path 8be of the head 8b. The oil stored in the reservoir 8bd is pressed by the pressure of the compressed air in the oil separator 8 and discharged from the oil discharge path 10 through the discharge hole and the discharge flow path 8be. In this embodiment, the oil discharge path 10 is connected to the suction side of the compressor body 2 so that the oil discharged from the oil discharge path 10 is recovered in the compressor body 2 . A valve element 10a is provided in the oil discharge path 10 so that the oil discharge path 10 can be opened and closed.

The valve body 10a is an electromagnetic valve whose opening is controlled by the controller 11 based on time. A normally open ON-OFF solenoid valve, for example, is used as the solenoid valve of the valve body 10a. In this embodiment, an example of using a normally open ON-OFF solenoid valve as the valve element 10a is shown, but the present invention is not limited to this. For example, it is possible to use a valve body 10a that enables three or more levels of control including an intermediate stage of "open (including slightly open)" or "closed (including slightly closed)" state. That is, it is also possible to permit (partially permit) or restrict (partially prohibit) the circulation of the stored oil according to the degree of opening of the valve body 10a.

The control unit 11 is a part that performs various controls of the oil-fed compressor 1A. In the control unit 11, for example, various controls of the oil-fed compressor 1A are realized through cooperation between the CPU and programs. In addition, a part may be configured in an analog manner. In this embodiment, the control unit 11 has a user interface (not shown) for inputting pressure set values and various set values. Controls the degree of opening.

Next, the opening degree control of the valve body 10a by the control unit 11 of this embodiment will be described with reference to FIG. FIG. 2 is a time chart of the opening control of the valve element 10a by the controller 11 of the oil-fed compressor 1A according to this embodiment.

The control unit 11 keeps the valve body 10a at the first opening degree during the first period Tc, and keeps the valve body 10a larger than the first opening degree during the second period To after the first period Tc. The holding at the second degree of opening is repeated. Specifically, as shown in FIG. 2, the control unit 11 transmits an ON signal to the valve body 10a to keep the valve body 10a in the "closed" state during the first period Tc. During the second period To after the first period Tc, the control unit 11 turns off the transmission of the signal to the valve body 10a to keep the valve body 10a in the "open" state. Further, the control unit 11 transmits an ON signal to the valve body 10a during the first period Tc after the second period To has passed, and keeps the valve body 10a in the "closed" state, and repeats these controls. Since the valve body 10a is a normally open ON-OFF solenoid valve, when the power is lost, the valve body 10a is held in the "open" state, and the oil that is secondary separated by the element 8a and drips overflows from the reservoir 8bd. can be suppressed.

The first period Tc is the time until a predetermined amount of oil is accumulated in the reservoir 8bd, and the second period To is the predetermined amount of oil accumulated in the reservoir 8bd during the first period Tc. It is the time until discharge. The predetermined amount of oil stored in the storage portion 8bd can be set, for example, to an amount or less that can prevent the oil stored in the storage portion 8bd from flowing back into the discharge pipe 8bb.

Further, the first period Tc is, for example, the time measured until the predetermined amount of oil is accumulated in the reservoir 8bd, and the second period To is, for example, the predetermined amount of oil is discharged from the reservoir 8bd. is the time measured up to The measured first period Tc and second period To are input to and stored in the control unit 11 . The control unit 11 controls the opening degree of the valve body 10a based on the stored first period Tc and second period To.

Therefore, in the oil-fed compressor 1A, the valve body 10a is "closed" during the first period Tc, and a predetermined amount of oil is stored in the reservoir 8bd. Further, in the oil-fed compressor 1A, the valve body 10a is "opened" during the second period To after the first period Tc has passed, and a predetermined amount of oil stored in the storage portion 8bd is discharged through the discharge hole and the discharge passage. The oil is discharged to the suction side of the compressor main body 2 via 8be and the oil discharge path 10 .

It should be noted that the second period To is preferably longer than or equal to the measured time until the predetermined amount of oil is discharged from the reservoir 8bd. The reason is as follows. First, due to deterioration of the oil or the like, the flow velocity of the oil flowing through the discharge hole, the discharge passage 8be, and the oil discharge passage 10 becomes slow, and the time required for a predetermined amount of oil to be discharged from the reservoir 8bd was measured. This is because it may be longer than time. Second, the element 8a becomes clogged with usage time, the amount of oil that can be retained decreases, the amount of oil that drips from the element 8a per unit time increases, and the amount of oil that accumulates in the reservoir 8bd increases. This is because there are cases.

[effect]
The oil-fed compressor 1A according to the present embodiment includes a compressor body 2 that compresses gas while injecting oil, a first oil separator 6 that separates oil from the compressed gas discharged from the compressor body 2, The second oil separator 8 further separates the oil from the compressed gas from which the oil has been separated by the first oil separator 6, and the second oil separator 8 has a reservoir 8bd for storing the separated oil. A discharge piping system 9 through which the recovered compressed gas flows, an oil discharge path 10 for discharging the oil stored in the reservoir 8bd from the reservoir 8bd, a valve body 10a provided in the oil discharge path 10, and a valve body A control unit 11 for controlling the opening degree of 10a based on time.

Conventionally, the oil discharge path 10 for discharging the oil in the reservoir 8bd was provided with, for example, an orifice with a constant degree of opening to continuously discharge the oil together with the compressed air. In the oil-fed compressor 1A, the opening degree of the valve body 10a provided in the oil discharge path can be controlled (changed) based on time. Then, in the oil-filled compressor 1A of the present embodiment, if control is performed to increase the time held in a state in which the opening degree of the valve body 10a is smaller than the opening degree of the orifice (the valve body 10a may be closed), The amount of compressed air discharged via the oil discharge path 10 can be reduced compared to before, and as a result, a decrease in compression efficiency of the oil-fed compressor 1A can be suppressed.

Further, in the oil-fed compressor 1A of the present embodiment, even when the amount of compressed air discharged due to the downsizing of the air compressor is reduced and the amount of dripping oil is further reduced, the first period Tc is lengthened to The opening of the valve body 10a can be reduced until the oil accumulates at 8bd. After the oil is accumulated in the reservoir 8bd, the opening degree of the valve body 10a is increased to discharge the oil accumulated in the reservoir 8bd within a predetermined time. Therefore, it is possible to reduce the amount of compressed air that is discharged together with the oil, thereby suppressing a decrease in the compression efficiency of the oil-fed compressor.

Further, in the oil-fed compressor 1A of the present embodiment, even when the load on the compressor body is reduced to reduce the discharge amount of compressed air and the amount of dripping oil is reduced, the first period Tc is lengthened and The opening of the valve body 10a can be reduced until the oil is accumulated. After the oil is accumulated in the reservoir 8bd, the opening degree of the valve body 10a is increased to discharge the oil accumulated in the reservoir 8bd within a predetermined time. Therefore, it is possible to reduce the amount of compressed air that is discharged together with the oil, thereby suppressing a decrease in the compression efficiency of the oil-fed compressor.

Further, the control unit 11 related to the oil-filled compressor 1A of the present embodiment maintains the valve body 10a at the first opening degree during the first period Tc, and the second period To after the first period Tc has passed. It repeats holding the valve body 10a at the second degree of opening, which is larger than the first degree of opening. Therefore, it is possible to prevent the oil discharge path 10 from clogging and being unable to discharge the oil.

Further, the control unit 11 related to the oil-fed compressor 1A of the present embodiment closes the valve body 10a at the first opening degree and opens the valve body 10a at the second opening degree. Therefore, after the oil is stored in the reservoir 8bd, the oil accumulated in the reservoir 8bd can be discharged. Therefore, it is possible to reduce the amount of compressed air that is discharged together with the oil, thereby suppressing a decrease in the compression efficiency of the oil-fed compressor.

Further, the control unit 11 of the oil-fed compressor 1A of the present embodiment controls the second period To to be longer than the time for discharging the oil accumulated in the reservoir 8bd during the first period Tc. As a result, the oil accumulated in the reservoir 8bd during the first period Tc can be discharged during the second period To, and oil can be prevented from remaining in the reservoir 8bd. Therefore, it is possible to suppress the oil from overflowing from the reservoir 8bd.

Also, the valve body 10a of the oil-fed compressor 1A of this embodiment uses a normally open ON-OFF solenoid valve. Therefore, control of the flow rate of the oil flowing through the oil discharge path 10 by the controller 11 can be simplified. In addition, even if the valve body 10a cannot be controlled due to loss of power or the like, the valve will be in the "open" state, and oil will accumulate in the reservoir 8bd, preventing the oil from overflowing from the reservoir 8bd.

Further, the oil discharge path 10 of the oil-fed compressor 1A of the present embodiment communicates with the low-pressure side of the compressor body 2 at the downstream opening, and the oil secondarily separated from the compressed gas by the second oil separator 8 is discharged. It is discharged to the low pressure side of the compressor body 2 . Therefore, the oil separated by the second oil separator 8 is not discharged to the outside and can be reused for compressing gas in the compressor body 2 .

The second oil separator 8 of the oil-fed compressor 1A of this embodiment includes a cylindrical case 8c with a closed upper end and an open lower end, and a cylindrical case 8c located inside the case 8c with open upper and lower ends. It has a filter (element 8 a ) and a discharge pipe 8 bb extending upward from the bottom of the filter and having an opening at the upper end located inside the filter and communicating with a discharge piping system 9 . Therefore, the filter (element 8a) can be lifted upward by removing the case 8c and can be easily replaced.

Also, the first oil separator 6 of the oil-fed compressor 1A of the present embodiment is a gas-liquid separator of a swirl separation system. The swirling separation type gas-liquid separator has a simple structure and can reduce costs.

(Second embodiment)
FIG. 3 is a schematic diagram showing the configuration of an oil-fed compressor 1B according to a second embodiment of the present invention. The oil-filled compressor 1B according to this embodiment differs from the oil-filled compressor 1A according to the first embodiment in the following points.

First, the oil-fed compressor 1B has a variable speed mechanism in the electric motor 3. That is, while the oil-filled compressor 1A according to the first embodiment is under constant speed control, the oil-filled compressor 1B according to this embodiment is under variable speed control.

Further, in the oil-fed compressor 1B according to the present embodiment, since the electric motor 3 is provided with a variable speed mechanism, the amount of oil accumulated in the reservoir 8bd is determined by the load factor (rotation speed/maximum rotation speed) of the compressor main body 2. × 100%). Therefore, while the control unit 11 of the oil-filled compressor 1A according to the first embodiment controls the opening degree of the valve body 10a based on time, the control unit 11 of the oil-filled compressor 1B according to the present embodiment , the opening of the valve body 10a is controlled based on the load factor of the compressor body 2 and time.

The variable speed mechanism provided in the electric motor 3 is the inverter 20, for example. Inverter 20 is electrically connected to electric motor 3 and control unit 11 and converts electric power to be supplied to electric motor 3 according to a command from control unit 11 .

For example, based on the pressure detected by the pressure sensor 9b, the control unit 11 changes the amount of power supplied from the inverter 20 to the electric motor 3 according to the user's set pressure, and performs variable speed control of the compressor body 2. Variable speed control includes proportional control (P control), proportional integral control (PI control), PID control in which differential control (D control) is added to PI control, no-load operation control, and the like.

　There are the following methods for no-load operation control. For example, when the pressure detected by the pressure sensor 9b is equal to or higher than the user's set pressure, the intake valve 5 is closed to limit the amount of air sucked into the compressor body 2. Further, when the pressure detected by the pressure sensor 9b is equal to or higher than the user's set pressure, the intake valve 5 is closed and the electric motor 3 is rotated at a predetermined number of revolutions (for example, the user's set pressure is secured and maintained). (lowest possible rotation speed).

The inverter 20 of the oil-fed compressor 1B according to the present embodiment changes the amount of electric power supplied to the electric motor 3 and controls the load factor of the compressor main body 2 by the control method described above. Although the variable speed control of the oil-filled compressor 1B by the inverter 20 has been described, the variable-speed control of the oil-filled compressor 1B may be performed by another method.

In the oil-filled compressor 1B according to this embodiment, the load factor of the compressor main body 2 is changed according to the user's set pressure, and the amount of compressed air to be discharged is changed. Therefore, the amount of oil that is secondarily separated by the oil separator 8 and accumulated in the reservoir 8bd changes depending on the load factor of the compressor main body 2 during control. Therefore, when the opening degree of the valve body 10a is controlled based on time, when the compressor body 2 is at a low load factor, the amount of oil accumulated in the reservoir 8bd decreases and the amount of compressed air discharged together with the oil increases. end up In order to suppress such an increase in the amount of compressed air, the opening degree of the valve body 10a is controlled according to the load factor of the compressor main body 2. FIG.

FIG. 4 is a graph showing changes in the load factor of the compressor body 2 over time, and a time chart of the opening degree control of the valve body 10a by the control unit 11 for the oil-fed compressor 1B according to this embodiment.

The amount of oil stored in the reservoir 8bd can be estimated from the load factor of the compressor body 2 and the operating time. Therefore, the controller 11 of this embodiment controls the opening of the valve body 10a based on the load factor of the compressor body 2 and the operating time.

Specifically, the valve body 10a is held at the first opening while the integrated values A1, A2, A3, and A4 of the product of the load factor of the compressor body 2 and the operating time are less than a predetermined value. Then, when the integrated values A1, A2, A3, and A4 of the product of the load factor of the compressor body 2 and the operating time reach a predetermined value, the valve body 10a is set to a second opening larger than the first opening for a predetermined period of time. Hold To.

The amount of oil that accumulates in the reservoir 8bd when the integrated value of the product of the load factor of the compressor body 2 and the operating time reaches a predetermined value can suppress the backflow of the oil and the inflow into the discharge pipe 8bb. amount (acceptable amount of reservoir 8bd) or less. Moreover, it is preferable that the predetermined period To is equal to or longer than the time measured until the predetermined amount of oil stored in the storage portion 8bd is discharged. The reason is the same as the reason for the second period To of the first embodiment described above.

[effect]
The oil-fed compressor 1B according to the present embodiment includes a compressor main body 2 that compresses gas while injecting oil, a first oil separator 6 that separates oil from the compressed gas discharged from the compressor main body 2, The second oil separator 8 further separates the oil from the compressed gas from which the oil has been separated by the first oil separator 6, and the second oil separator 8 has a reservoir 8bd for storing the separated oil. A discharge piping system 9 through which the separated compressed gas flows, an oil discharge path 10 for discharging the oil stored in the reservoir 8bd from the reservoir 8bd, a valve body 10a provided in the oil discharge path 10, and a compressor. A control unit 11 is provided for controlling the opening degree of the valve body 10a based on the load factor of the main body 2 and time.

The amount of oil stored in the reservoir 8bd can be estimated from the load factor of the compressor body 2 and the time. Therefore, in the oil-fed compressor 1B of the present embodiment configured as described above, for example, the timing of releasing the valve body 10a from the closed state should be controlled according to an increase in the amount of oil estimated from the load factor and time. As a result, it is possible to prevent the oil from overflowing in excess of the allowable amount of the reservoir 8bd, and to reduce the amount of compressed air discharged through the oil discharge path 10 compared to before. As a result, a decrease in compression efficiency of the oil-fed compressor can be suppressed.

In addition, the control unit 11 of the oil-fed compressor 1B according to the present embodiment keeps the valve body from operating while the integrated values A1, A2, A3, and A4 of the product of the load factor of the compressor body 2 and the operating time are less than a predetermined value. 10a is held at the first opening, and when the integrated value of the product of the load factor of the compressor body 2 and the operating time reaches a predetermined value, the valve body 10a is set to a second opening larger than the first opening. Hold for a period of time. Therefore, it is possible to prevent the oil discharge path 10 from clogging and being unable to discharge the oil.

Further, in the oil-fed compressor 1B according to the present embodiment, the oil accumulated in the reservoir 8bd until the integrated values A1, A2, A3, and A4 of the product of the load factor of the compressor body 2 and the operating time reach a predetermined value. is less than the allowable amount of oil that can be stored in the reservoir 8bd. Therefore, it is possible to suppress the oil from overflowing from the reservoir 8bd.

In addition, in the oil-fed compressor 1B according to the present embodiment, the predetermined period To during which the valve body 10a is held at the second opening larger than the first opening is the product of the load factor of the compressor body 2 and the operating time. This period is longer than the time for discharging the oil accumulated in the reservoir 8bd until the integrated value reaches the predetermined value. As a result, the oil accumulated in the reservoir 8bd can be discharged during the predetermined period To until the integrated values A1, A2, A3, and A4 of the product of the load factor of the compressor body 2 and the operating time reach predetermined values. It is possible to suppress the oil from remaining in the portion 8bd. Therefore, it is possible to suppress the oil from overflowing from the reservoir 8bd.

Further, the control unit 11 related to the oil-fed compressor 1B of the present embodiment closes the valve body 10a at the first opening degree and opens the valve body 10a at the second opening degree. Therefore, after the oil is stored in the reservoir 8bd, the oil accumulated in the reservoir 8bd can be discharged. Therefore, it is possible to reduce the amount of compressed air that is discharged together with the oil, thereby suppressing a decrease in the compression efficiency of the oil-fed compressor.

(Third embodiment)
1 and 3 are schematic diagrams showing the configuration of an oil-fed compressor 1C according to a third embodiment of the present invention. FIG. 5 is a graph showing changes over time in the pressure detected by the pressure sensor 9b, and a time chart of the opening control of the valve body 10a by the control unit 11, in the oil-fed compressor 1C according to the third embodiment of the present invention. is. FIG. 6 shows a graph showing changes over time in the load factor of the compressor body 2 and changes over time in the pressure detected by the pressure sensor 9b for the oil-fed compressor 1C according to the third embodiment of the present invention. 10A and 10B are graphs and time charts of opening degree control of the valve body 10a by the control unit 11;

The oil-fed compressor 1C according to the present embodiment is first and second in that the control unit 11 controls the timing of narrowing the opening of the valve body 10a based on the pressure detected by the pressure sensor 9b while the valve body 10a is being released. It differs from the oil-fed

compressors

1A and 1B according to the second embodiment.

Specifically, the control unit 11 of the oil-fed

compressors

1A and 1B according to the first and second embodiments holds the valve body 10a at a second opening degree larger than the first opening degree during the period To. After a lapse of time, the valve body 10a is controlled to a first opening smaller than the second opening. On the other hand, in the control unit 11 of the oil-filled compressor 1C according to the present embodiment, the decrease (P1-P2) in the pressure detected by the pressure sensor 9b that detects the pressure in the discharge piping system 9 during the opening of the valve body 10a is predetermined. At the timing when the value ΔP is reached, the opening degree of the valve body 10a is reduced.

That is, while the valve body 10a is held at the second opening, the control unit 11 of the oil-filled compressor 1C opens the valve body 10a at the timing when the decrease in the pressure (P1-P2) detected by the pressure sensor 9b reaches the predetermined value ΔP. is controlled to a first opening smaller than the second opening.

Therefore, in the control unit 11 of the oil-fed

compressors

1A and 1B according to the first and second embodiments, the period To for holding the valve body 10a at the second opening is a set predetermined time. On the other hand, the control unit 11 of the oil-filled compressor 1C controls the valve body based on the fact that the compressed air is discharged after the oil accumulated in the reservoir 8bd is discharged, and the pressure of the discharge piping system 9 is reduced. Controls the period (To1 to To3) during which the valve 10a is held at the second opening.

Note that FIG. 5 shows a case in which the period during which the valve body 10a is held at the first opening degree is controlled based on time, as in the oil-fed compressor 1A of the first embodiment. FIG. 6 shows a case where the period during which the valve body 10a is held at the first opening is controlled based on the load factor of the compressor main body 2 and time, as in the oil-fed compressor 1B of the second embodiment. .

In addition, the oil-fed compressor 1C can control the control unit 11 to detect clogging of the oil discharge path 10 based on the decrease (P1-P2) in the pressure detected by the pressure sensor 9b and notify the clogging.

That is, when the control unit 11 determines that the period from when the valve body 10a is set to the second degree of opening until the decrease (P1-P2) in the pressure detected by the pressure sensor 9b reaches a predetermined value ΔP exceeds the predetermined period. , to report anomalies.

You can also do the following to prevent malfunctions. The control unit 11 records the number of times the ratio ((P1-P2)/To) of the decrease in the pressure detected by the pressure sensor 9b ((P1-P2)/To) with respect to the elapsed time To during the release of the valve body 10a does not reach a predetermined value. do. Then, when the number of times reaches a predetermined number, an abnormality is reported.

As means for notifying the abnormality, various means and devices can be used, such as displaying a warning on the display device provided in the control unit 11, activating and emitting a warning light, and generating a warning sound from a speaker. can.

[effect]
The oil-fed compressor 1C according to the present embodiment includes a compressor main body 2 that compresses gas while injecting oil, a first oil separator 6 that separates oil from the compressed gas discharged from the compressor main body 2, The second oil separator 8 further separates the oil from the compressed gas from which the oil has been separated by the first oil separator 6, and the second oil separator 8 has a reservoir 8bd for storing the separated oil. A discharge piping system 9 through which the recovered compressed gas flows, an oil discharge path 10 for discharging the oil stored in the reservoir 8bd from the reservoir 8bd, a valve body 10a provided in the oil discharge path 10, and a discharge pipe. A pressure sensor 9b for detecting the pressure of the system 9, and a control unit 11 for controlling the opening degree of the valve body 10a based on time. The timing for narrowing the opening of the valve body 10a is controlled based on the detected pressures P1 and P2.

When the valve body 10a is released in the oil-fed compressor 1C configured as described above, the pressure detected by the pressure sensor 9b decreases as the amount of oil in the reservoir 8bd decreases. Therefore, in the oil-filled compressor 1C, if the timing for narrowing the opening of the valve body 10a is controlled based on the pressure detected by the pressure sensor 9b during release of the valve body 10a, the remaining amount of oil in the reservoir 8bd becomes zero. It is possible to prevent useless continuation of the opening of the valve body 10a after it becomes. As a result, the amount of compressed air discharged via the oil discharge path 10 can be reduced compared to before, so that the reduction in compression efficiency of the oil-fed compressor can be suppressed.

Further, the control unit 11 of the oil-filled compressor 1C according to the present embodiment controls the valve body when the drop (P1-P2) in the pressure detected by the pressure sensor 9b during release of the valve body 10a reaches a predetermined value ΔP. Reduce the opening of 10a. Therefore, even if the oil discharge passage 10 is clogged with foreign matter and the passage area is reduced, and the oil accumulated in the reservoir 8bd is discharged more than normally, the oil accumulated in the reservoir 8bd can be discharged reliably. It can be carried out.

Further, the control unit 11 of the oil-filled compressor 1C according to the present embodiment controls the valve body when the drop (P1-P2) in the pressure detected by the pressure sensor 9b during release of the valve body 10a reaches a predetermined value ΔP. Close 10a. Therefore, the amount of compressed air discharged from the oil discharge path 10 can be reduced compared to before, and a decrease in compression efficiency of the oil-fed compressor can be suppressed.

Further, the control unit 11 of the oil-filled compressor 1C according to the present embodiment closes the valve body 10a for a predetermined period and then opens the valve body 10a, and the pressure detected by the pressure sensor 9b during the opening of the valve body 10a decreases ( When P1-P2) reaches a predetermined value ΔP, the valve body 10a is closed. Therefore, after the oil is stored in the reservoir 8bd, the oil accumulated in the reservoir 8bd can be discharged. Therefore, the amount of compressed air discharged from the oil discharge path can be reduced compared to before, and a decrease in compression efficiency of the oil-fed compressor can be suppressed.

In addition, in the oil-fed compressor 1C according to the present embodiment, the predetermined period during which the valve body 10a is closed changes depending on the load factor of the compressor main body 2. Therefore, even if the oil-filled compressor is of variable speed control, the oil can be discharged from the reservoir 8bd after a predetermined amount of oil is stored in the reservoir 8bd. Compressed air discharge can be reduced compared to before, and a decrease in compression efficiency of the oil-fed compressor can be suppressed.

Further, in the control unit 11 of the oil-fed compressor 1C according to the present embodiment, the period from when the valve body 10a is released until the decrease in the pressure detected by the pressure sensor 9b (P1-P2) reaches a predetermined value ΔP is , if the predetermined period is exceeded, an abnormality is reported. This makes it possible to detect clogging of the oil discharge path 10 and notify the user of the fact.

In addition, the control unit 11 of the oil-filled compressor 1C according to the present embodiment records the number of times the rate of decrease in the pressure detected by the pressure sensor 9b with respect to the elapsed time does not reach a predetermined value while the valve body 10a is being released. reaches a predetermined number of times, an abnormality is reported. As a result, erroneous detection of clogging of the oil discharge path 10 can be suppressed, and clogging of the oil discharge path 10 can be accurately notified to the user.

Also, the pressure sensor 9b of the oil-fed compressor 1C according to the present embodiment is provided in the vicinity of the location where the discharge piping system 9 is connected to the second oil separator 8. Thereby, the pressure drop in the second oil separator 8 can be quickly detected.

It should be noted that the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. Also, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

In addition, each of the above configurations, functions, etc. may be realized by hardware, for example, by designing a part or all of them with an integrated circuit. Moreover, each of the above configurations, functions, and the like may be realized by software by a processor (microcomputer) interpreting and executing a program for realizing each function. Information such as programs, tables, and files that implement each function can be stored in a recording device such as a memory, a hard disk, an SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD.

It should be noted that the embodiment of the present invention may have the following aspects. Each of the oil-filled

compressors

1A and 1B according to the first and second embodiments can incorporate the control of the oil-filled compressor 1C according to the third embodiment.

Further, in the first to third embodiments, the case where the compressor main body 2 is of the screw rotor type and has a pair of

screw rotors

2a and 2b has been described as an example, but the present invention is not limited to this. The compressor main body may be provided with, for example, one screw rotor (including a combined gate rotor system) and a plurality of gate rotors. Further, the compressor main body may be of a positive displacement type other than the screw rotor type (specifically, a rotary type such as a scroll type or a claw type, or a reciprocating type, etc.).

In addition, in the first to third embodiments, the case where the electric motor 3 is used as the drive source has been described as an example, but the present invention is not limited to this, and for example, an internal combustion engine, an engine that utilizes natural energy such as wind power or water power. It can be applied even if there is

Also, in the first to third embodiments, the case where the inverter 20 is used in the variable speed mechanism has been described as an example, but it is not limited to this. For example, when the drive source is an internal combustion engine, a speed change gear or a fuel supply control device can be used as the variable speed mechanism. Further, when the drive source is an engine that utilizes natural energy such as wind power or hydraulic power, a variable speed mechanism can be a transmission gear or a clutch mechanism.

Also, in the first to third embodiments, the case where air is used as the gas to be compressed has been described as an example, but the present invention is not limited to this, and other gases such as nitrogen may be used.

In addition, in the first to third embodiments, the case where the control unit 11 is provided in the oil-filled compressor has been described as an example, but the control unit 11 is not limited to this. The lubricating compressor may be remotely controlled by wire or wirelessly. Further, part of the control may be performed by the controller 11 in the oil-fed compressor, and the other control may be performed by a remote control device.

DESCRIPTION OF

SYMBOLS

1A, 1B, 1C... Oil supply type compressor, 2... Compressor main body, 3... Electric motor, 6... 1st oil separator, 8... 2nd oil separator (oil separator), 8a... Element, 8b... Head, 8ba Introduction channel 8bb Discharge pipe 8bc Outlet channel 8bd Reservoir 8be Discharge channel 8c Case 9 Discharge piping system

9a Check valve

9b Pressure sensor 10 Oil discharge path 10a...Valve body 11...Control unit 20...Inverter

Claims

a compressor body that compresses gas while injecting oil;
a first oil separator for separating oil from the compressed gas discharged from the compressor main body;
a second oil separator further separating oil from the compressed gas from which the oil has been separated by the first oil separator, and having a reservoir for storing the separated oil;
a discharge piping system through which the compressed gas from which the oil is separated by the second oil separator flows;
an oil discharge path for discharging the oil stored in the reservoir from the reservoir;
a valve body provided in the oil discharge path;
and a control unit that controls the opening of the valve element based on time.
a compressor body that compresses gas while injecting oil;
a first oil separator for separating oil from the compressed gas discharged from the compressor main body;
a second oil separator further separating oil from the compressed gas from which the oil has been separated by the first oil separator, and having a reservoir for storing the separated oil;
a discharge piping system through which the compressed gas from which the oil is separated by the second oil separator flows;
an oil discharge path for discharging the oil stored in the reservoir from the reservoir;
a valve body provided in the oil discharge path;
an oil-fed compressor, comprising: a controller that controls the opening of the valve element based on the load factor of the compressor body and time.
a compressor body that compresses gas while injecting oil;
a first oil separator for separating oil from the compressed gas discharged from the compressor main body;
a second oil separator further separating oil from the compressed gas from which the oil has been separated by the first oil separator, and having a reservoir for storing the separated oil;
a discharge piping system through which the compressed gas from which the oil is separated by the second oil separator flows;
an oil discharge path for discharging the oil stored in the reservoir from the reservoir;
a valve body provided in the oil discharge path;
a pressure sensor for detecting the pressure in the discharge piping system;
A control unit that controls the opening degree of the valve body based on time,
The control unit is an oil-fed compressor that controls the timing of narrowing the opening of the valve element based on the pressure detected by the pressure sensor while the valve element is open.
The oil-fed compressor according to claim 1,
The control unit holds the valve body at a first opening during a first period, and holds the valve body at a first opening greater than the first opening during a second period after the first period. An oil-fed compressor that repeats holding at two degrees of opening.
The oil-fed compressor according to claim 4,
The control unit closes the valve body at the first degree of opening and opens the valve body at the second degree of opening.
The oil-fed compressor according to claim 4,
The oil-fed compressor, wherein the control unit controls the second period to be longer than the time for discharging the oil accumulated in the reservoir during the first period.
The oil-fed compressor according to claim 2,
The control unit maintains the valve body at a first opening while an integrated value of the product of the load factor of the compressor main body and time is less than a predetermined value, and maintains the valve body at a first opening. An oil-fed compressor that holds the valve body at a second degree of opening larger than the first degree of opening for a predetermined period of time when the integrated value of the products reaches the predetermined value.
The oil-fed compressor according to claim 7,
The control unit closes the valve body at the first degree of opening and opens the valve body at the second degree of opening.
The oil-fed compressor according to claim 7,
An oil-fed compressor, wherein the amount of oil accumulated in the reservoir until the integrated value reaches the predetermined value is equal to or less than an allowable amount of oil that can be accumulated in the reservoir.
The oil-fed compressor according to claim 7,
The oil-fed compressor, wherein the predetermined period is longer than a period of time for discharging the oil accumulated in the reservoir until the integrated value reaches the predetermined value.
The oil-fed compressor according to claim 3,
The control unit throttles the degree of opening of the valve body when a decrease in the pressure detected by the pressure sensor during release of the valve body reaches a predetermined value.
The oil-fed compressor according to claim 3,
The control unit opens the valve body after closing the valve body for a predetermined period of time, and closes the valve body when a decrease in pressure detected by the pressure sensor during the opening of the valve body reaches a predetermined value. Oil-fed compressor.
The oil-fed compressor according to claim 12,
The predetermined period of time is an oil-fed compressor that varies according to the load factor of the compressor body.
The oil-fed compressor according to claim 3,
The control unit notifies an abnormality when a period from when the valve body is released to when the pressure detected by the pressure sensor reaches a predetermined value exceeds a predetermined period.
The oil-fed compressor according to claim 3,
The control unit records the number of times the rate of decrease in the pressure detected by the pressure sensor with respect to the elapsed time does not reach a predetermined value while the valve body is being released, and when the number of times reaches the predetermined number of times, an abnormality is reported. type compressor.
The oil-fed compressor according to claim 3,
The oil-fed compressor, wherein the pressure sensor is provided near a location where the discharge piping system connects to the second oil separator.
The oil-fed compressor according to any one of claims 1 to 3,
An oil-fed compressor, wherein the valve body is a normally open ON-OFF solenoid valve.
The oil-fed compressor according to any one of claims 1 to 3,
The oil discharge path is an oil supply type in which a downstream opening communicates with the low pressure side of the compressor body, and the oil secondarily separated from the compressed gas by the second oil separator is discharged to the low pressure side of the compressor body. compressor.
The oil-fed compressor according to any one of claims 1 to 3,
The second oil separator includes a cylindrical case with a closed upper end and an open lower end, a cylindrical filter positioned inside the case and open at the upper and lower ends, and an upper end extending upward from below the filter. and a discharge pipe having an opening positioned inside the filter and communicating with the discharge piping system.
The oil-fed compressor according to any one of claims 1 to 3,
The first oil separator is a gas-liquid separator of a swirl separation type oil-fed compressor.