JP4685466B2 - Secondary separation lubricating oil recovery structure for oil-cooled screw compressor - Google Patents

Description

The present invention relates to a secondary separated lubricating oil recovery structure for an oil-cooled screw compressor, and more specifically, a compressed gas from which lubricating oil is primarily separated in a receiver tank is introduced into the oil separator, and the oil separator The present invention relates to a secondary separation lubricating oil recovery structure for recovering the lubricating oil collected by secondary separation (referred to as “ secondary separation lubricating oil” in the present invention) in a compressor body.

  The oil-cooled screw compressor includes a compressor body that compresses a gas to be compressed together with lubricating oil for lubrication, cooling, and sealing of a compression working space.

Therefore, since the compressed gas discharged from the compressor main body is in the state of a gas-liquid mixed fluid with the lubricating oil, the gas-liquid mixed fluid discharged from the compressor main body is once introduced into the receiver tank and the lubricating oil was first separation, then two additional oil content of the compressed gas after the primary separation of the lubricant is performed by introducing into the oil separator having an oil separator element or the like, it remains in the state of mist in the compressed gas Next, it is separated and collected so that clean compressed gas from which oil has been removed can be supplied to the consumer side.

The primary separated lubricating oil in the receiver tank (primary separation lubricating oil) is again the compressor body is introduced into the fuel supply port of the compressor body after cooling through the oil cooler lubrication, cooling and compression action space Used for sealing.

In addition, the lubricating oil ( secondary separation lubricating oil) collected by secondary separation in the oil separator is transported to the suction port of the compressor main body by a recovery pipe communicating with one end to the oil reservoir of the oil separator. It is introduced into the compressor body through the suction port together with the compressed gas (see Patent Document 1 and Patent Document 2) or introduced into the compressor body through the suction side or the oil supply port (oil return point) ( (See cited document 3).

Prior art document information of the present invention includes the following.
JP-A-8-189489 JP-A-6-101777 Japanese Patent Laid-Open No. 3-96668

As described above, the amount of loss of the lubricating oil can be reduced by collecting the secondary separated lubricating oil collected in the oil separator again in the compressor body.

However, among the above-described conventional techniques, when the collected secondary separated lubricating oil is collected in the compressor main body together with the compressed gas through the suction port of the compressor main body, the volume of the secondary separated lubricating oil sucked in Accordingly, the suction amount of the compressed gas decreases, and the suction gas in contact with the relatively high temperature secondary separation lubricating oil expands due to heating, so the suction amount of the compressed gas decreases and the compression efficiency decreases. To do.

In this way, when the secondary separated lubricating oil collected in the oil separator is sucked and collected from the suction port 13 of the compressor body 10 together with the compressed gas, the amount of suction of the compressed gas to the compressor body is as follows. Since this causes a reduction in compression efficiency, a drill hole is formed through the casing 12 and opened in the inner peripheral surface 20b of the rotor chamber 20, and this drill hole is formed as a recovery passage 23 and an oil separator. It is also conceivable that the secondary separated lubricating oil collected in the above step is recovered in the compression working space of the compressor body 10 via the recovery passage 23 (see FIG. 6).

  However, in such an oil-cooled screw compressor main body 10, the tooth portions 211 and 221 formed on the screw rotors 21 and 22 have the narrowest tooth width at the outer peripheral ends 211a and 221a as shown in FIG. When the collection passage 23 having a diameter larger than the tooth width of the outer peripheral end 221a is formed, the collection passage 23 is formed even when the outer peripheral end 221a of the tooth portion 221 overlaps the collection passage 23. 23 cannot be completely closed, and as shown in FIG. 6 and FIG. 7, the adjacent compression working space with the tooth portion 221 as a boundary communicates via the recovery passageway 23.

  As a result, the compressed gas leaks from the compression working space having a high pressure among the adjacent compression working spaces to the compression working space having a low pressure, and the compression efficiency is lowered.

  Thus, in the case of forming the recovery passage 23 that opens on the inner peripheral surface 20b of the rotor chamber 20, if the reduction of the compression efficiency due to the communication between adjacent compression working spaces is to be avoided, the recovery passage 23 described above is used. Needs to be formed to be equal to or smaller than the tooth width at the outer peripheral end 221a of the tooth portion 221.

  However, since the width of the tooth portion 221 is narrowest at the outer peripheral end 221a of the screw rotor 22 as described above, if the recovery passageway 23 is to be reduced to a size that can be closed by the outer peripheral end 221a of the tooth portion 221. It is necessary to form a very small diameter hole. Such a small-diameter drill hole cannot be drilled by a single drilling operation, and the depth of the hole is increased step by step while repeating the discharge of drill powder by moving the drill blade up and down. Work is required, and the work of forming the collection passage 23 is complicated and takes a long time.

The secondary separation lubricating oil separated in the oil separator is sent to the compressor main body 10 side by the pressure of the compressed gas in the oil separator.For example, when the consumption of compressed air on the consumption side increases, The amount of compressed gas that passes through the oil separator increases and the amount of secondary separated lubricating oil that is collected increases, while the pressure in the oil separator that communicates with the receiver tank and the receiver tank decreases. The pressure difference between the internal pressure and the compression working space decreases, and a large amount of the secondary separated lubricating oil collected in the oil separator cannot be smoothly collected in the compression working space.

As described above, when the secondary separation lubricating oil collected in the oil separator is not smoothly recovered and remains in the oil reservoir of the oil separator, the secondary separation lubricating oil collected in the oil separator is compressed gas. At the same time, it may be supplied to the consumer.

Therefore, the present invention has been made to eliminate the above-mentioned drawbacks of the prior art, and a first object of the present invention is to compress the secondary separated lubricating oil separately from the suction of the compressed gas. by directly recovered into the space, the secondary by heating with separate lubrication oil can be prevented a reduction in the intake air amount, moreover, inlet formed to introduce a secondary separation lubricating oil to the compression action space Even when the adjacent compression working space is formed in a size that does not allow communication, the opening width of the inlet can be made relatively large. An object of the present invention is to provide a secondary separation lubricating oil recovery structure that can facilitate the formation of.

Another object of the present invention, the pressure difference of the compressed working space and oil separator with the consumption of changes in the compressed gas even when the changes have been trapped in the oil separator two An object of the present invention is to provide a secondary separated lubricating oil recovery structure for an oil-cooled screw compressor that can stably recover the secondary separated lubricating oil in the compression working space of the compressor body.

In order to achieve the above object, the secondary separated lubricating oil recovery structure of the oil-cooled screw compressor according to the present invention accommodates a pair of male and female screw rotors 21 and 22 in the rotor chamber 20 formed in the casing 12. Then, an oil-cooled compressor body 10 that compresses a compressed gas (for example, air) together with lubricating oil by meshing rotation of the pair of screw rotors 21 and 22, and gas-liquid mixing from the compressor body 10 with lubricating oil. oil supply passage for introducing the lubricating oil introducing compressed gas discharged as a fluid with a receiver tank 30 to primary separation, the primary separation lubricating oil primary separation in the receiver tank 30 into the rotor chamber 20 (oil supply pipe 61 a fuel supply port 11), wherein the receiver tank 30 primary separation lubricating oil introducing compressed gas after separation, the secondary lubricant remaining in the compressed gas to the secondary separation In oil-cooled screw compressor 1 equipped with the oil separator 40 having an oil sump for collecting the separated lubricating oil therein,
On the discharge-side end wall 20a of the rotor chamber 20 at a position where the tooth side surface 211b of either the male or female screw rotor (male screw rotor 21 in the example of FIG. 2) faces through a minute gap allowing rotation. the teeth form a feed port 24 which is open in the width less the size of the side surface 211b, communicates the oil reservoir 41 in the oil separator 40 to the rotor chamber 20 through the inlet 24, the two A recovery flow path (recovery piping 62, recovery passage 23) for the next separated lubricating oil is provided separately from the oil supply flow path (Claim 1).

The introduction port 24 is preferably provided at a position communicating with the compression action space after the intake air is closed (Claim 2).
More preferably, it is provided at a position where it communicates with the compression action space until it has advanced by 1 pitch after the intake air is closed.

Further, oil supply means for supplying lubricating oil to the bearing of the discharge-side bearing chamber 25 of the compressor body 10 is provided, and an oil discharge passage 26 that communicates the bearing chamber 25 with the rotor chamber 20 through the introduction port 24. It is good also as a structure which connects the said recovery flow path (recovery piping 62, recovery passage 23 ') connected with the oil sump 41 of the said oil separator 40 to the said oil discharge path 26 (Claim 4; FIG. 5). reference).

The secondary separated lubricating oil is recovered from the compressor main body 10 through the inlet 24 formed in the discharge side end wall 20a of the rotor chamber 20, so that the inlet 24 can be either a male or female screw rotor. It became closed by the tooth part side surface (211b or 221b) of (21 or 22).

Since this tooth part side surface (211b or 221b) is formed wider than the outer peripheral end (211a or 221a) of the tooth part, the introduction port 24 is formed by the tooth part side surface (211b or 221b). Even if it is a size that can be closed, that is, a size that does not cause communication between adjacent compression working spaces, the opening width of the introduction port 24 can be made relatively large, and the operation of forming the introduction port 24 can be performed. The secondary separation lubricating oil recovery structure can be provided which is relatively easy and does not cause a reduction in compression efficiency even when the inlet 24 having such a large opening width is formed.

Further, since the introduction port 24 is formed at a position communicating with the compression working space after the intake air is closed, there is no contact between the secondary separation lubricating oil and the intake gas, and the reduction of the intake gas amount can be prevented.

In particular, by introducing the secondary separation lubricant into the compression working space immediately after the intake air is closed or at a relatively early stage after the intake air is closed, for example, until one pitch is advanced after the intake air is closed. A sufficient pressure difference between the separator and the compression space can be secured, and the secondary separated lubricating oil can be recovered smoothly.

Further, oil supply means for supplying lubricating oil to a bearing in a bearing chamber 25 provided on the discharge side of the compressor body is provided, and drainage oil that communicates the bearing chamber 25 with the rotor chamber 20 through the introduction port 24. In the configuration in which the passage 26 is provided and the oil sump 41 of the oil separator 40 is communicated with the rotor chamber 20 via the drain oil passage 26, the bearing chamber 25 is provided in the drain passage 26 during the operation of the compressor. Since there is a flow of lubricating oil (exhaust oil) from to the rotor chamber 20, the lubricating oil collected by the oil separator 40 is drawn into the compression working space by this entraining action (ejector action) of the exhaust oil. For example, even when the pressure difference between the oil separator 40 and the compression working space decreases with the consumption of compressed gas on the consumption side, the secondary separated lubricating oil can be recovered smoothly. secondary separate lubrication oil recovery that can It is possible to provide an elephant.

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

[Example 1]
FIG. 1 is an overall configuration diagram of an oil-cooled screw compressor according to the present invention.

This oil-cooled screw compressor 1 sucks a compressed gas such as air, compresses it together with lubricating oil, and discharges a compressed gas as a gas-liquid mixed fluid with the lubricating oil, by introducing a compressed gas liquid gas liquid by introducing the compressed gas discharged in the state of the mixed fluid separating lubricant in the receiver tank 30 and the receiver tank to (primary separation) is a primary separator, it included in the compressed gas includes an oil separator 40 for lubricating oil collecting in secondary separations, primary separation lubricating oil primary separation in the receiver tank 30, the oil supply pipe having an oil cooler 50 by the pressure in the receiver tank 30 The secondary separated lubricating oil introduced into the oil supply port 11 of the compressor main body 10 through 61 and secondarily separated in the oil separator 40 and collected in the oil reservoir 41 is compressed through the recovery pipe 62. In machine body 10 For that it is configured to be able to yield in the same configuration as the oil-cooled type screw compressor described in the prior art.

However, the oil-cooled screw compressor described as the prior art is configured to recover the secondary separated lubricating oil to the compressor body 10 via the compressed gas suction port 13 or the oil supply port 11. In the oil-cooled screw compressor 1 of the present invention, the inlet 24 is formed in the discharge side end wall 20a of the rotor chamber 20 that houses the pair of male and female screw rotors (21, 22), and the oil separator in that the secondary separating lubricating oil recovery structure for recovering the compressed working space of the compressor body 10 through the inlet 24 a trapped secondary separation lubricating oil is formed at 40, conventional oil-cooled Features that are not found in screw compressors (see FIG. 2).

  In the embodiment shown in FIG. 1, an example in which the receiver tank 30 and the oil separator 40 are separately provided is shown, but the oil separator 40 may be provided in the receiver tank, for example. It is also possible to employ the configuration of the present invention in a tank-integrated compressor in which the compressor body 10 is provided in the receiver tank.

  In the present embodiment, the casing 12 that forms the rotor chamber 20 that rotatably accommodates the pair of male and female screw rotors 21 and 22 is engaged with the casing body 12a and the lid as shown in FIG. The rotor chamber 20 surrounded by the casing body 12a and the lid body 12b is formed by covering the discharge side end of the casing body 12a with the lid body 12b.

  The male and female screw rotors 21 and 22 housed side by side in the rotor chamber 20 are connected to the outer peripheral ends 211a and 221a of the tooth portions 211 and 221 formed on the screw rotors 21 and 22, respectively. While rotating through a minute gap with the inner peripheral surface 20b of the chamber 20 (see FIG. 3), the tooth side surfaces 211b and 221b on the discharge side are opposed to the discharge side end wall 20a of the rotor chamber 20 via a minute gap. The compression working space is formed by rotating, and the compressed gas sucked through the suction port 13 provided on the upper side of the casing 12 and the suction passage 14 provided continuously to the suction port 13 is supplied to the compression target space. It compresses within the compression space and is configured to be able to discharge through a discharge port 15 provided on the bottom side of the casing 12.

  In the compressor body 10 of the present embodiment thus formed, the introduction port 24 communicating with the rotor chamber 20 is formed in the end wall 20a of the rotor chamber 20 as described above. In the embodiment shown in FIG. 4, a recovery passage 23 formed by a drill hole penetrating the lid 12b in the thickness direction is provided, and one end opening of the recovery passage is used as the introduction port 24 described above.

  As described above, the male and female screw rotors 21 and 22 rotate while the tooth side surfaces 211b and 221b on the discharge side face each other through a minute gap with the end wall 20a on which the recovery passage 23 is formed, and In the example shown in FIG. 3, the introduction port 24 described above is provided at a position facing the tooth side surface 211 b on the discharge side of the male screw rotor 21 through a minute gap, that is, in the rotation locus of the tooth side surface 211 b. In addition, the recovery passage 23 has a tooth side surface 211b on the introduction port 24 because the opening width is smaller than the width of the tooth side surface 211b of the portion that passes over the introduction port 24. The state changes with rotation of the screw rotors 21 and 22 between the overlapped closed state and the groove formed between the tooth portions, that is, the state communicating with the compression working space.

  Since the tooth part side surface 211b of the screw rotors 21 and 22 is wider than the outer peripheral end 211a of the tooth part, the adjacent compression working space with the tooth part 211 as a boundary is interposed via the recovery passageway 23. Even if the opening width of the introduction port 24 is formed to be smaller than the width of the tooth side surface 211b of the portion passing over the introduction port 24 as described above so as not to communicate, the opening width is compared. Can be large.

As a result, it is possible to provide a secondary separation lubricating oil recovery structure including a recovery passage 23 that can be formed relatively easily and in a short time without causing a reduction in compression efficiency. ing.

  Preferably, the introduction port 24 of the recovery passage 23 is preferably provided in the rotation locus of the tooth portion 211 of the male rotor 21 which is wider than the tooth portion 221 formed in the female rotor 22, thereby the introduction port 24. The selection of the opening width can be further expanded.

  However, the formation of the recovery passage 23 is not limited to the male rotor 21 side, and it may be provided on the female rotor 22 side. In this case as well, the inlet of the recovery passage 23 is similarly formed with respect to the width of the tooth side surface of the female rotor 22. The width is formed small, and the adjacent compression working space is prevented from communicating through the recovery passageway 23.

The formation position of the recovery passage 23 (introduction port 24) is that the introduction port 24 is blocked by the tooth side surface (211b or 221b) as the screw rotors 21 and 22 rotate, and a groove portion (compression) formed between the tooth portions. Position and size at which communication with the working space) can be repeated, that is, the tooth portion of the portion passing through the inlet 24 within the rotation locus of the tooth portion side surface (211b or 221b) of any screw rotor Any position and size may be provided as long as the opening width is equal to or smaller than the width of the side surface 211b, but preferably the communication of the recovery passage 23 to the compression working space is made after the intake air is closed preferably formed at a position that is performed on the compressed working space, thereby, the recovery of the secondary separation lubricating oil for compression action space row for compression action space after confinement intake It and will be, without secondary separation lubricating oil is in contact with the compressed gas before confinement intake, heated by the secondary separation lubricating oil, it is possible to prevent the suction amount of the compressed gas is reduced by the expansion or the like.

  More preferably, it is preferable to provide communication with the compression working space of the inlet port 24 at a position where it can be performed immediately after the intake air is closed or at a relatively early stage after the intake air is closed. The formation position is adjusted so that the introduction port 24 communicates with the compression action space until the pitch advances.

In this way, the pressure in the compression working space is relatively low by configuring the recovery passage 23 to communicate with the compression working space immediately after the intake air is closed or at a relatively early stage after the intake air is closed. At this time, the secondary separated lubricating oil can be introduced, and the pressure difference between the oil separator 40 and the compression working space can be increased, whereby the secondary separated lubricating oil can be smoothly recovered.

[Action]
When the compressor main body 10 is driven by a drive source such as an engine or a motor in the compressor 1 having the secondary separation lubricating oil recovery structure including the recovery passageway 23 configured as described above, the compressor main body 10 becomes the suction port. The compressed gas is sucked from 13 and compressed with the lubricating oil, and the gas-liquid mixed fluid of the compressed gas and the lubricating oil is discharged to the receiver tank 30.

  Lubricating oil in the gas-liquid mixed fluid discharged to the receiver tank 30 accumulates at the bottom of the receiver tank 30, and compressed oil that is primarily separated from the lubricating oil is an oil separator 40 provided at the outlet of the receiver tank 30. In this oil separator 40, the oil component contained in the compressed gas is collected in a mist state, and clean compressed gas from which oil has been removed is supplied to the consumer side.

  Lubricating oil separated in the receiver tank 30 and accumulated at the bottom of the receiver tank 30 is pushed out by the pressure of the compressed gas in the receiver tank 30, and is supplied to the compressor main body 10 via an oil supply pipe 61 provided with an oil cooler 50. It is supplied to the oil filler port 11 and is used again for lubrication, cooling and sealing of the compression working space of the compressor main body 10, and the inside of the circulation system formed between the compressor main body 10 and the receiver tank 30 by repeating the above-described operation. Circulate.

  The lubricating oil introduced into the oil separator 40 together with the compressed gas without being completely separated in the receiver tank 30 is separated from the compressed gas in the oil separator 40 and collected in the oil reservoir 41 of the oil separator 40. Is done.

  Since the oil separator 40 has a relatively high pressure due to the compressed gas introduced from the receiver tank 30, the lubricating oil collected in the oil reservoir 41 of the oil separator 40 is the oil separator 40. The pressure in 40 reaches the recovery passageway 23 provided in the compressor main body 10 via the recovery pipe 62 provided with the orifice 63.

Since one end opening of the recovery passage 23, that is, the introduction port 24 communicates with the rotor chamber 20 via the discharge side end wall 20a of the rotor chamber 20 formed in the casing 12 of the compressor body 10, The recovery passageway 23 has a state in which the tooth side surface (211b or 221b) formed in the screw rotors 21 and 22 and the introduction port 24 overlap with each other along with the rotation of the screw rotors 21 and 22, and the tooth side surface. When the introduction port 24 is positioned between (211b or 221b) and the state is repeatedly changed to the state where it is communicated with the compression working space, and the recovery passageway 23 is communicated with the compression working space as described above, A secondary separation lubricant is introduced into the working space.

  As described above, the introduction port 24 is provided in the discharge side end wall 20a of the rotor chamber 20 provided in the compressor body 10, so that the adjacent compression working space does not communicate with each other. Even when the opening width of the introduction port 24 is formed to be equal to or smaller than the width of the tooth side surfaces 211b and 221b, the diameter of the introduction port 24 and hence the recovery passage 23 can be made relatively large.

Further, when the inlet 24 is provided at a position communicating with the compression action space after the intake air is closed, the recovered secondary separated lubricating oil does not come into contact with the compressed gas before the intake air is closed. With the expansion of the compressed gas before it is warmed, the amount of compressed gas sucked does not decrease. Especially, it is in the compression working space immediately after the intake is closed or at a relatively early time after the intake is closed. by forming the inlet port 24 at a position communicating with, it is possible to introduce secondary separation lubricating oil to the compression action space in a relatively low state of the pressure, a very smooth recovery of the secondary separation lubricant It is possible to do.

Even when the introduction port 24 is formed at a position communicating with the compression action space before the intake air is closed, the suction passage 14 and the recovery passage 23 are separated from each other, and the secondary passage via the suction port 13 is provided. Compared with the case where the separated lubricating oil is introduced into the compressor main body 10, the contact time between the secondary separated lubricating oil and the compressed gas before closing the intake air is extremely short, and the secondary separated lubricating oil with respect to the compression working space Since the intake air is closed in a relatively short time after the introduction of the intake gas, even if the intake gas expands by being heated by the secondary separation lubricating oil, the intake gas amount may decrease. The amount is negligible.

[Example 2]
FIG. 5 is a cross-sectional view of the screw compressor body 10 in another secondary separation lubricating oil recovery structure of the present invention.

In this compressor body 10, the secondary separation lubricating oil is recovered in the compression working space of the compressor body 10 through the inlet 24 formed in the discharge side end wall 20 a of the rotor chamber 20. Although the points that have are the same as the secondary separation lubricating oil recovery structure of the first embodiment described above, in the first embodiment discussed above, the drilled holes through the lid 12b in the thickness direction and the collection path 23 In contrast to the fact that one end of the recovery passage 23 is used as the inlet 24 described above, in this embodiment, the exhaust that communicates the bearing chamber 25 provided on the discharge side of the compressor body 10 and the rotor chamber 20. An oil passage 26 is provided, and one end opening of the drain oil passage 26 is formed with the introduction port 24 described above. By introducing the secondary separated lubricating oil from the oil separator 40 into the drain oil passage 26, It merges with lubricating oil flowing in the passage 26 secondary separation lubricant The difference is that a recoverable to the compression action space.

  The oil discharge passage 26 is provided to collect the lubricating oil supplied to the bearing in the bearing chamber 25 into the compression working space. For example, the oil supply passage from the receiver tank 30 to the oil supply port 11 of the compressor body 10 is provided. By branching the pipe 61 and communicating with the bearing chamber 25 described above, the lubricating oil lubricates the bearing in the bearing chamber 25 and then is collected in the rotor chamber 20 via the oil drain passage 26. As described above, during the driving of the compressor body 10, the lubricant oil flows from the bearing chamber 25 to the rotor chamber 20 in the oil discharge passage 26.

  The introduction port 24 formed in the end wall 20a of the rotor chamber 20 is provided at a position in the rotation locus of the tooth side surface of either the male or female screw rotor, as in the example described in the first embodiment. And the opening width of the tooth portion side surface (211b or 221b) at the position passing through the introduction port 24 is less than the width of the tooth portion. It forms so that a communication with the compression action space in the position between part side surfaces may be repeated.

  Further, the introduction port 24 of the oil discharge passage 26 has a compression action space after the intake air is closed, more preferably a compression action space immediately after the intake air is closed or a relatively early stage after the intake air is closed, for example, after the intake air is closed. The point that it is preferable to form at a position communicating with the compression working space until it advances by one pitch is the same as in the case of the first embodiment.

  In the illustrated example, the introduction port 24 of the oil discharge passage 26 is described as communicating with the compression working space on the female rotor 22 side as described above, but the recovery in the first embodiment described with reference to FIG. 2 described above. Similarly to the passage 23, the male rotor 21 may be formed at a position communicating with the compression working space, and the formation position is not limited to the illustrated embodiment.

As described above, the oil drain passage 26 for returning the lubricating oil supplied to the bearing of the bearing chamber 25 provided on the discharge side of the compressor body 10 to the rotor chamber 20 is provided, and the oil separator 40 is provided in the oil drain passage 26. in by introducing the collected secondary separation lubricating oil, since that is configured to recover the second separation lubricating oil through the oil discharge passage 26, the second separation lubricating oil recovery structure of this embodiment is there, it becomes possible to smoothly recover the secondary separation lubricating oil recovery further compared to the structure second separation lubricating oil described as the aforementioned first embodiment.

That is, the secondary separated lubricating oil collected by the oil separator 40 is drawn into the oil discharge passage 26 by the entraining action (ejection action) of the lubricating oil (drain oil) from the bearing chamber 25 to the rotor chamber 20. For example, even if the consumption of compressed gas on the consumption side increases and the pressure difference in the oil separator 40 and the pressure difference in the compression working space decrease, the secondary separated lubricating oil can be recovered smoothly. Accordingly, it is possible to suitably prevent the secondary separated lubricating oil in the oil separator 40 from being collected without being collected and supplied to the consumer side together with the compressed gas.

In addition, the processing performed on the compressor main body 10 is a recovery passage for introducing the secondary separated lubricating oil into the existing exhaust oil passage 26 that recovers the lubricating oil (exhaust oil) that lubricates the bearing on the discharge side. It is only necessary to perform the processing to form 23 ', and the passage that needs to be newly processed in order to recover the secondary separated lubricating oil can be shortened.

  Further, since the communication with the rotor chamber 20 is performed through the preliminarily formed drainage passage 26, the recovery passage 23 ′ newly formed by processing has a relatively large diameter. However, the size of the inlet 24 provided in the discharge side end wall 20a of the rotor chamber 20 is not affected, and the recovery passage 23 'can be easily formed.

  As a result, the processing time for forming the recovery passage 23 'can be shortened, and the recovery passage can be easily formed.

  In addition, in the case where the recovery passage 23 as described with reference to FIG. 2 is provided in the discharge side end wall 20a of the rotor chamber 20 formed in the compressor body 10 separately from the oil discharge passage 26, the rotor Although there is a possibility that the sealing performance of the discharge side end wall 20a of the chamber 20 may be deteriorated, the rotor chamber 20 is configured such that the recovery passage 23 'communicates with the oil discharge passage 26 as described above. Therefore, the risk of a decrease in sealing performance is reduced.

  In general, male and female screw rotors 21 and 22 are arranged side by side in the horizontal direction, and a suction port 13 is arranged at the upper part of one end side of the screw rotors 21 and 22 and a discharge port 15 is arranged at the lower part of the other end side. In the machine main body 10, when the recovery passage 23 is opened from the outer peripheral side of the rotor chamber 20 as shown in FIG. 6, the connection portion of the recovery pipe 62 to the recovery passage 23 is provided below the compressor main body 10. Become. That is, when the recovery passage introduction port is opened on the rotor chamber circumferential surface having the same pitch as that of the introduction port 24 of the present embodiment that opens to the discharge side end wall 20a, the introduction port approaches the suction side from the discharge side end surface side. As the rotor moves along the seal line at the outer peripheral edge of the rotor, the pipe connection part is also located relatively below the compressor body (casing), making it difficult to connect pipes and connecting pipes. It is difficult to check for oil leaks in the parts.

  However, in the case of the configuration of the present embodiment, the connection portion of the recovery pipe 62 provided in the recovery passage 23 ′ is disposed on the upper side or the side of the compressor body 10. There is an advantage that the work is easy and the oil leakage inspection of the pipe connection part is easy. That is, in the embodiment of FIG. 5, the connection portion of the recovery pipe 62 is disposed in the 9 o'clock direction (side) as viewed from the discharge side to the oil discharge passage 26 from the discharge side. When the passage 26 is rotated 90 ° in the clockwise direction when viewed from the discharge side to the suction side, the connecting portion is arranged in the 12 o'clock direction (upper side). It is easy to check for oil leaks.

1 is an overall configuration diagram of an oil-cooled screw compressor according to the present invention. The schematic sectional drawing of a compressor main body. The side perspective view of the compressor main body seen from the discharge side. Explanatory drawing of the position of the collection | recovery channel | path corresponding to a rotor. The schematic sectional drawing of a compressor main body. Side surface perspective view of the compressor body viewed from the discharge side (conventional). Explanatory drawing of the position of the collection | recovery channel | path corresponding to a rotor (conventional).

DESCRIPTION OF SYMBOLS 1 Oil-cooled screw compressor 10 Compressor main body 11 Oil supply port 12 Casing body 12a Casing main body 12b Cover body 13 Suction port 14 Suction passage 15 Discharge port 20 Rotor chamber 20a Discharge side end wall 20b Inner peripheral surface 21 Male rotors 211a and 221a Outer end (Of rotor teeth)
211b, 221b Tooth side surface 22 Female rotor 23 Recovery passage 24 Inlet 25 Bearing chamber 26 Oil discharge passage 30 Receiver tank 40 Oil separator 41 Oil reservoir 50 Oil cooler 61 Oil supply piping 62 Recovery piping 63 Orifice 64 Discharge piping

Claims (4)

An oil-cooled compressor main body that accommodates a pair of male and female screw rotors in a rotor chamber formed in a casing, and compresses a compressed gas together with lubricating oil by meshing rotation of the pair of screw rotors, and the compressor oil introducing a receiver tank for the compressed gas is introduced primary separating lubricating oil discharged as a gas-liquid mixed fluid of lubricating oil from the main body, the primary separation lubricating oil primary separation in the receiver tank to the rotor chamber oil and the flow path, said primary separating lubricant in the receiver tank by introducing compressed gas after separation, to collect the lubricating oil remaining in the compressed gas as a secondary separate lubrication oil to the secondary separation In an oil-cooled screw compressor provided with an oil separator having a reservoir inside ,
On the discharge side end wall of the rotor chamber, an introduction port that opens with a size equal to or smaller than the width of the tooth side surface is provided at a position facing the tooth side surface of the male or female screw rotor via a minute gap. formed, and characterized in that the reservoir of the oil in the oil separator communicates with the rotor chamber through the inlet, wherein the secondary separating lubricating oil said oil supply passage to the recovery passage provided separately secondary separate lubrication oil recovery structure of oil-cooled type screw compressor. The secondary separation lubricating oil recovery structure for an oil-cooled screw compressor according to claim 1, wherein the introduction port is provided at a position communicating with the compression working space after the intake air is closed. 3. The secondary separated lubricating oil recovery structure for an oil-cooled screw compressor according to claim 2, wherein the introduction port is provided at a position communicating with a compression working space from when the intake air is closed until one pitch is advanced. . An oil supply means for supplying lubricating oil to a bearing in a discharge side bearing chamber of the compressor body is provided, and an oil discharge passage is provided for communicating the bearing chamber with the rotor chamber through the introduction port . secondary separate lubrication oil recovery structure of the oil reservoir communicating with said recovery flow path the oil discharge passage path oil-cooled type screw compressor according to claim 1 to 3 any one of claims, characterized in that communicating with.

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