Patent Application
20250188929
The present invention relates to a screw compressor, and more particularly to a screw compressor including a suction flow path that opens to working chambers in a suction process.
A screw compressor includes a pair of male and female screw rotors that rotates while meshing with each other and a casing that houses both the screw rotors. In this compressor, a plurality of working chambers are formed by lobe grooves of both the screw rotors and an inner wall surface of the casing surrounding them. The casing is provided with a suction flow path for introducing gas (working fluid) from the outside to the working chambers and a discharge flow path for introducing compressed gas from the working chambers to the outside. The working chambers increase the volume, while moving in the axial direction with rotation of both the screw rotors, to suck gas through the suction flow path, then decrease the volume to compress the gas, and finally discharge the compressed gas through the discharge flow path. As described above, the working chambers sequentially repeat a suction process for sucking the gas through the suction flow path, a compression process for compressing the gas, and a discharge process for discharging the compressed gas through the discharge flow path.
As the suction flow paths of the screw compressor, there are a suction flow path on the male rotor side and a suction flow path on the female rotor side that communicate with the working chambers in the suction process in the rotor axial direction, and are located on the downstream side with respect to a virtual plane passing through both center axis lines of the male and female rotors (see, for example, Patent Document 1).
Incidentally, in a liquid flooded type screw compressor, when miniaturization is attempted in order to reduce the cost, it is inevitable to increase the speed of the screw rotors. In a liquid free type screw compressor, since the sealing effect by liquid supply as in the liquid flooded type cannot be expected, the screw rotors are often operated by high speed rotation in order to reduce a leakage loss from the working chambers.
In the case where the screw rotors are operated by high speed rotation, the working fluid flowing into the working chambers from the suction flow path is accelerated to match the high speed rotation. If the working fluid flowing in the suction flow path decelerates, the speed of the working fluid to flow into the working chambers from the suction flow path is accordingly reduced, and thus the amount of acceleration of the working fluid increases. This means that the driving power of the screw compressor increases. Therefore, an increase in the amount of acceleration of the working fluid due to the deceleration of the working fluid flowing in the suction flow path results in an energy loss (hereinafter, referred to as an acceleration loss in some cases) and deteriorates the efficiency of the screw compressor.
In the screw compressor described in Patent Document 1, the working fluid flows in the suction flow path on the male rotor side and the suction flow path on the female rotor side, which communicate with the working chambers in the suction process in the rotor axial direction, from the branch side of both the flow paths toward the downstream side with respect to the virtual plane (see the void arrow in
It is conceivable that the screw compressor described in Patent Document 1 has a structure in which the flow path cross-sectional areas of the suction flow path on the male rotor side and the suction flow path on the female rotor side is substantially constant from the branch side to the downstream end. In the suction flow path on the male rotor side and the suction flow path on the female rotor side having such a structure, when the flow rate of the working fluid gradually decreases toward the downstream side, the flow speed of the working fluid accordingly decelerates toward the downstream side. Therefore, as described above, the deceleration of the working fluid flowing through the suction flow path on the male rotor side and the suction flow path on the female rotor side causes an acceleration loss, and thus the efficiency of the screw compressor is deteriorated.
The present invention has been made in order to solve the above problems, and an object thereof is to provide a screw compressor capable of reducing an acceleration loss caused by deceleration of working fluid flowing through a suction flow path.
The present application includes a plurality of means for solving the above problems, and one example thereof is a screw compressor including: a male rotor that has a first rotor lobe section and is rotatable around a first axis line; a female rotor that has a second rotor lobe section and is rotatable around a second axis line; and a casing that has a housing chamber for housing the first rotor lobe section and the second rotor lobe section in a state where they mesh with each other and forms a plurality of working chambers together with the first rotor lobe section and the second rotor lobe section. Further, the casing has a suction flow path that introduces working fluid from an outside of the casing to the working chambers in a suction process. The suction flow path includes a male-side flow path that opens in an axial direction of the male rotor with respect to working chambers on the male rotor side among the working chambers in the suction process and extends from a first starting end that is positioned on one side with respect to a virtual plane passing through the first axis line and the second axis line and is on an inflow side of the working fluid to a first termination end positioned on the other side with respect to the virtual plane, and a female-side flow path that opens in an axial direction of the female rotor with respect to working chambers on the female rotor side among the working chambers in the suction process and extends from a second starting end that is positioned on the one side with respect to the virtual plane and is on the inflow side of the working fluid to a second termination end positioned on the other side with respect to the virtual plane. In addition, a flow path wall defining the male-side flow path includes a male-side first flow path wall that faces a suction-side end face side of the first rotor lobe section and extends from the first starting end to the first termination end, a flow path wall defining the female-side flow path includes a female-side first flow path wall that faces a suction-side end face side of the second rotor lobe section and extends from the second starting end to the second termination end. The male-side first flow path wall is configured such that at least a partial area in a range from the first starting end to the first termination end is closer to the first rotor lobe section from the first starting end side toward the first termination end side, or the female-side first flow path wall is configured such that at least a partial area in a range from the second starting end to the second termination end is closer to the second rotor lobe section from the second starting end side toward the second termination end side.
According to the present invention, the male-side first flow path wall for the male-side flow path, which opens in the rotor axial direction with respect to the working chambers in the suction process, is closer to the first rotor lobe section toward the first termination end side, or the female-side first flow path wall in the female-side flow path is closer to the second rotor lobe section toward the second termination end side. Therefore, the flow path cross-sectional area of the male-side flow path decreases toward the first termination end side or the flow path cross-sectional area of the female-side flow path decreases toward the second termination end side. This causes the deceleration of the working fluid flowing through the male-side flow path or the female-side flow path to be suppressed, thereby reducing the acceleration loss caused by the deceleration of the working fluid flowing through the suction flow path.
Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.
Hereinafter, embodiments of a screw compressor of the present invention will be exemplarily described by using the drawings.
A schematic configuration of a screw compressor according to a first embodiment will be described by using
In
The male rotor 2 is configured with a rotor lobe section 21 having a plurality of spiral male lobes, and a suction-side shaft section 22 and a discharge-side shaft section 23 provided at both end of the rotor lobe section 21 in the axial direction. The rotor lobe section 21 has a suction-side end face 21a and a discharge-side end face 21b orthogonal to the axial direction (axis line Lm) at one end (left end in
The female rotor 3 is configured with a rotor lobe section 31 having a plurality of spiral female lobes, and a suction-side shaft section 32 and a discharge-side shaft section 33 provided at both end of the rotor lobe section 31 in the axial direction. The rotor lobe section 31 has a suction-side end face 31a and a discharge-side end face 31b orthogonal to the axial direction (axis line Lf) at one end (left end in
The casing 4 has a bottomed cylindrical main casing 41 that opens on one side (left side in
As depicted in
As depicted in
In addition, the casing 4 is provided with a suction flow path 60 that introduces gas from the outside of the casing 4 to the working chambers C. The suction flow path 60 communicates the outside of the casing 4 with the working chambers C in a suction process, and has a suction opening 61 that is an opening of the casing 4 on the outer wall side and a suction port 62 that is an opening on the bore 45 side.
For example, the suction opening 61 is provided at a position on one side (left side in
In the screw compressor 1 configured as described above, when the male rotor 2 depicted in
It should be noted that the screw compressor 1 of the present embodiment is configured in such a manner that the male rotor 2 is driven by the rotary driving source to drive the female rotor 3. However, the screw compressor 1 can also be configured in such a manner that the female rotor 3 is driven by the rotary driving source to drive the male rotor 2, or both the male and female rotors 2 and 3 are synchronously driven.
In addition, the screw compressor 1 of the present embodiment is illustrated as a liquid free type compressor without an injection port for injecting liquid such as oil or water into the working chambers C. However, a liquid flooded type screw compressor that injects liquid from an injection port into the working chambers C may be used. In the case where the screw compressor 1 is of a liquid free type, it is necessary to rotate the rotor lobe section 21 of the male rotor 2 and the rotor lobe section 31 of the female rotor 3 in a non-contact state, and rotary engaging means such as a timing gear for rotationally engaging the male rotor 2 and the female rotor 3 with each other is provided, but the illustration of the rotary engaging means is omitted in
Next, details of the structure of the suction flow path of the screw compressor according to the first embodiment will be described by using
As depicted in
The male-side branch flow path 72 and the female-side branch flow path 73 extend from the connection position (that is, the inflow position of the working fluid) with the introduction flow path 71 to the position of a closing part 42b of the casing 4 formed in a region on one side (lower side in
As depicted in
As depicted in
The first flow path wall 81 of the male-side branch flow path 72 is configured such that at least a partial area in a range from the starting end 75 to the male-side termination end 76 is gradually closer to the rotor lobe section 21 of the male rotor 2 from the starting end 75 side toward the male-side termination end 76 side. As similar to the above, the first flow path wall 91 of the female-side branch flow path 73 is configured such that at least a partial area in a range from the starting end 75 to the female-side termination end 77 is gradually closer to the rotor lobe section 31 of the female rotor 3 from the starting end 75 side toward the female-side termination end 77 side.
Specifically, the first flow path wall 81 of the male-side branch flow path 72 and the first flow path wall 91 of the female-side branch flow path 73 have shapes as depicted in, for example,
The first flow path wall 81 of the male-side branch flow path 72 is configured as a flat face equally distant from the suction-side end face 21a of the rotor lobe section 21 of the male rotor 2 in an area from a point 81a positioned in the vicinity of the starting end 75 of the male-side branch flow path 72 to a certain point 81b is, and is configured as an inclined face gradually closer to the suction-side end face 21a of the male rotor 2 from the certain point 81b toward a point 81c positioned at the male-side termination end 76. That is, the first flow path wall 81 extends such that the inclined face closer to the suction-side end face 21a of the male rotor 2 reaches the male-side termination end 76 from a position on the other side (upper side in
As similar to the above, the first flow path wall 91 of the female-side branch flow path 73 is configured as a flat face equally distant from the suction-side end face 31a of the rotor lobe section 31 of the female rotor 3 in an area from a point 91a positioned in the vicinity of the starting end 75 of the female-side branch flow path 73 to a certain point 91b, and is configured as an inclined face gradually closer to the suction-side end face 31a of the female rotor 3 from the certain point 91b toward a point 91c positioned at the female-side termination end 77. That is, the first flow path wall 91 extends such that the inclined face closer to the suction-side end face 31a of the female rotor 3 reaches the female-side termination end 77 from a position on the other side (upper side in
The first flow path wall 81 of the male-side branch flow path 72 and the first flow path wall 91 of the female-side branch flow path 73 can be configured to have shapes as depicted in, for example,
Specifically, the first flow path wall 81 of the male-side branch flow path 72 is configured as a flat face equally distant from the suction-side end face 21a of the male rotor 2 in the area from the point 81a to the point 81b (similar to the case of
As similar to the above, the first flow path wall 91 of the female-side branch flow path 73 is configured as a flat face equally distant from the suction-side end face 31a of the female rotor 3 in the area from the point 91a to the point 91b (similar to the case of
In the suction flow path 60 of the screw compressor 1 configured as described above, the working fluid flowing in from the introduction flow path 71 is sucked into the working chambers C through the suction port 62 that opens in the axial direction while flowing from the starting end 75 of the male-side branch flow path 72 toward the male-side termination end 76, and also is sucked into the working chambers C through the suction port 62 that opens in the axial direction while flowing from the starting end 75 of the female-side branch flow path 73 toward the female-side termination end 77.
Next, the action and effect of the screw compressor according to the first embodiment will be described in comparison with a screw compressor of a comparative example. First, the structure of a suction flow path of the screw compressor in the comparative example will be described by using
The main different point between a screw compressor 101 of the comparative example and the screw compressor 1 according to the present embodiment is that the shapes of a male-side branch flow path 172 and a female-side branch flow path 173 formed in a suction-side casing 142 are different in a suction flow path 160 formed in a casing 104. Other configurations of the screw compressor 101 of the comparative example are similar to those of the screw compressor 1 according to the present embodiment.
Specifically, a first flow path wall 181 of the male-side branch flow path 172 of the comparative example is configured to be maintained equally distant from the suction-side end face 21a of the rotor lobe section 21 of the male rotor 2 from the starting end 75 to the male-side termination end 76 as depicted in
In details, the first flow path wall 181 of the male-side branch flow path 172 and the first flow path wall 191 of the female-side branch flow path 173 have shapes as depicted in, for example,
In the screw compressor 101 of the comparative example, the working fluid flowing in from the introduction flow path 71 of the suction flow path 160 depicted in
In the screw compressor 101 of the comparative example, the first flow path wall 181 of the male-side branch flow path 172 is maintained substantially equally distant from the suction-side end face 21a of the male rotor 2, and the first flow path wall 191 of the female-side branch flow path 173 is maintained substantially equally distant from the suction-side end face 31a of the female rotor 3. This causes the working fluid flowing through the male-side branch flow path 172 and the female-side branch flow path 173 to decelerate from the starting end 75 side toward the female-side termination end 77 side. Therefore, the decelerated working fluid increases, by the deceleration, in the amount of acceleration accelerated by the male rotor 2 rotating at a high speed when it is sucked into the working chambers C through the suction port 62, thereby causing an acceleration loss and deteriorating the efficiency of the screw compressor.
In contrast to that, in the screw compressor 1 according to the present embodiment, the first flow path wall 81 of the male-side branch flow path 72 is configured such that at least a partial area in the range from the starting end 75 to the male-side termination end 76 is gradually closer to the rotor lobe section 21 of the male rotor 2 from the starting end 75 side toward the male-side termination end 76 side. As similar to the above, the first flow path wall 91 of the female-side branch flow path 73 is configured such that at least a partial area in the range from the starting end 75 to the female-side termination end 77 is gradually closer to the rotor lobe section 31 of the female rotor 3 from the starting end 75 side toward the female-side termination end 77 side. Accordingly, since there are areas where the flow path cross-sectional areas of the male-side branch flow path 72 and the female-side branch flow path 73 decrease toward the male-side termination end 76 side and the female-side termination end 77 side, the deceleration of the working fluid flowing through the male-side branch flow path 72 and the female-side branch flow path 73 can be accordingly suppressed as compared with the case of the configuration of the screw compressor 101 of the comparative example. Therefore, the acceleration amount when flowing from the male-side branch flow path 72 and the female-side branch flow path 73 into the working chambers C through the suction port 62 can be reduced, and the energy efficiency of the screw compressor 1 can be improved.
As described above, the screw compressor 1 according to the present embodiment includes: the male rotor 2 that has the rotor lobe section 21 (first rotor lobe section) and is rotatable around the axis line Lm (first axis line); the female rotor 3 that has the rotor lobe section 31 (second rotor lobe section) and is rotatable around the axis line Lf (second axis line); and the casing 4 that has the housing chamber 45 for housing the rotor lobe section 21 (first rotor lobe section) and the rotor lobe section 31 (second rotor lobe section) in a state where they mesh with each other and forms the plurality of working chambers C together with the rotor lobe section 21 (first rotor lobe section) and the rotor lobe section 31 (second rotor lobe section). The casing 4 has the suction flow path 60 that introduces the working fluid from the outside of the casing 4 to the working chambers C in the suction process. The suction flow path 60 has: the male-side branch flow path 72 (male-side flow path) that opens in the axial direction of the male rotor 2 with respect to the working chambers C on the male rotor 2 side among the working chambers C in the suction process and that extends from the first starting end 75, which is positioned on one side with respect to the virtual plane Pv passing through the axis line Lm (first axis line) and the axis line Lf (second axis line) and is on the inflow side of the working fluid, to the male-side termination end 76 (first termination end), which is positioned on the other side with respect to the virtual plane Pv; and the female-side branch flow path 73 (female-side flow path) that opens in the axial direction of the female rotor 3 with respect to the working chambers C on the female rotor 3 side among the working chambers C in the suction process and that extends from the second starting end 75, which is positioned on the one side with respect to the virtual plane Pv and is on the inflow side of the working fluid, to the female-side termination end 77 (second termination end), which is positioned on the other side with respect to the virtual plane Pv. The flow path wall defining the male-side branch flow path 72 (male-side flow path) includes the first flow path wall 81 (male-side first flow path wall) that faces the suction-side end face 21a side of the rotor lobe section 21 (first rotor lobe section) and extends from the first starting end 75 to the male-side termination end 76 (first termination end), and the flow path wall defining the female-side branch flow path 73 (female-side flow path) includes the first flow path wall 91 (female-side first flow path wall) that faces the suction-side end face 31a side of the rotor lobe section 31 (second rotor lobe section) and extends from the second starting end 75 to the female-side termination end 77 (second termination end). The first flow path wall 81 (male-side first flow path wall) is configured such that at least a partial area in a range from the first starting end 75 to the male-side termination end 76 (first termination end) is closer to the rotor lobe section 21 (first rotor lobe section) from the first starting end 75 side toward the male-side termination end 76 (first termination end), or the first flow path wall 91 (female-side first flow path wall) is configured such that at least a partial area in a range from the second starting end 75 to the female-side termination end 77 (second termination end) is closer to the rotor lobe section 31 (second rotor lobe section) from the second starting end 75 side toward the female-side termination end 77 (second termination end).
According to this configuration, the first flow path wall 81 (male-side first flow path wall) in the male-side branch flow path 72 (male-side flow path), which opens in the rotor axial direction with respect to the working chambers C in the suction process, is formed so as to be closer to the rotor lobe section 21 (first rotor lobe section) toward the male-side termination end 76 (first termination end) side, or the first flow path wall 91 (female-side first flow path wall) in the female-side branch flow path 73 (female-side flow path) is formed so as to be closer to the rotor lobe section 31 (second rotor lobe section) toward the female-side termination end 77 (second termination end) side. This causes the flow path cross-sectional area of the male-side branch flow path 72 (male-side flow path) to decrease toward the male-side termination end 76 (first termination end) side, or the flow path cross-sectional area of the female-side branch flow path 73 (female-side flow path) to decrease toward the female-side termination end 77 (second termination end) side. Accordingly, since the deceleration of the working fluid flowing through the male-side branch flow path 72 (male-side flow path) or the female-side branch flow path 73 (female-side flow path) is suppressed, the acceleration loss caused by the deceleration of the working fluid flowing through the suction flow path 60 can be reduced.
In addition, in the present embodiment, the first flow path wall 81 (male-side first flow path wall) has an inclined face that is gradually closer to the rotor lobe section 21 (first rotor lobe section) from the first starting end 75 side toward the male-side termination end 76 (first termination end) side, or the first flow path wall 91 (female-side first flow path wall) has an inclined face that is gradually closer to the rotor lobe section 31 (second rotor lobe section) from the second starting end 75 side toward the female-side termination end 77 (second termination end) side.
According to this configuration, the first flow path wall 81 (male-side first flow path wall) defining the male-side branch flow path 72 (male-side flow path) or the first flow path wall 91 (female-side first flow path wall) defining the female-side branch flow path 73 (female-side flow path) has the inclined face. This allows the flow path cross-sectional areas to be reduced without disturbing the flow of the working fluid in the male-side branch flow path 72 (male-side flow path) or the female-side branch flow path 73 (female-side flow path).
In addition, in the present embodiment, the inclined face in the first flow path wall 81 (male-side first flow path wall) extends from a position on the one side with respect to the virtual plane Pv to the male-side termination end 76 (first termination end), or the inclined face in the first flow path wall 91 (female-side first flow path wall) extends from a position on the one side with respect to the virtual plane Pv to the female-side termination end 77 (second termination end).
According to this configuration, by reducing the flow path cross-sectional area of the male-side branch flow path 72 (male-side flow path) or the female-side branch flow path 73 (female-side flow path) to the male-side termination end 76 (first termination end) or the female-side termination end 77 (second termination end), the deceleration suppressing effect of the working fluid flowing through the male-side branch flow path 72 (male-side flow path) or the female-side branch flow path 73 (female-side flow path) can be enhanced.
In addition, in the present embodiment, the first flow path wall 81 (male-side first flow path wall) is configured such that the inclined face extends from a position on the one side with respect to the virtual plane Pv to the certain first position 81d before reaching the male-side termination end 76 (first termination end), and such that an area from the first position 81d to the male-side termination end 76 (first termination end) is a flat face equally distant from the rotor lobe section 21 (first rotor lobe section), or the first flow path wall 91 (female-side first flow path wall) is configured such that the inclined face extends from a position on the one side with respect to the virtual plane Pv to the certain second position 91d before reaching the female-side termination end 77 (second termination end), and such that an area from the second position 91d to the female-side termination end 77 (second termination end) is a flat face equally distant from the rotor lobe section 31 (second rotor lobe section).
According to this configuration, the inclined face of the first flow path wall 81 (male-side first flow path wall) or the first flow path wall 91 (female-side first flow path wall) is limited before the male-side termination end 76 (first termination end) or the female-side termination end 77 (second termination end). This allows machining of the first flow path wall 81 (male-side first flow path wall) or the first flow path wall 91 (female-side first flow path wall) in the area reaching the male-side termination end 76 (first termination end) or the female-side termination end 77 (second termination end) to become easier than in the case of the inclined face.
In addition, in the present embodiment, the male-side branch flow path 72 (male-side flow path) is configured such that the direction from the first starting end 75 to the male-side termination end 76 (first termination end) corresponds to the rotation direction of the male rotor 2, and the female-side branch flow path 73 (female-side flow path) is configured such that the direction from the second starting end 75 to the female-side termination end 77 (second termination end) corresponds to the rotation direction of the female rotor 3.
According to this configuration, the direction of the working fluid flowing through the male-side branch flow path 72 (male-side flow path) and the female-side branch flow path 73 (female-side flow path) corresponds to the rotation direction of the male rotor 2 and the female rotor 3. Therefore, the pressure loss of the working fluid when flowing into the working chambers C from the male-side branch flow path 72 and the female-side branch flow path 73 can be reduced.
In addition, in the present embodiment, the casing 4 has: the main casing 41 (first casing) configured to house the rotor lobe section 21 (first rotor lobe section) and the rotor lobe section 31 (second rotor lobe section); and the suction-side casing 42 (second casing) that has the male-side branch flow path 72 (male-side flow path) and the female-side branch flow path 73 (female-side flow path), is attached to the main casing 41 (first casing), and is a member different from the main casing 41 (first casing).
Next, a screw compressor according to a second embodiment of the present invention will be described by using
The main different point between a screw compressor 1A according to the second embodiment and the screw compressor 1 according to the first embodiment is that the shapes of a male-side branch flow path 72A and a female-side branch flow path 73A formed in a suction-side casing 42A are different in a suction flow path 60A formed in a casing 4A. Other configurations of the screw compressor 1A of the present embodiment are similar to those of the screw compressor 1 according to the first embodiment.
Specifically, among the flow path walls defining the male-side branch flow path 72A, a second flow path wall 82A positioned outward in the radial direction of the male rotor 2 is configured to be partially and substantially flush with the male-side inner peripheral wall face 45a that is a wall face of the housing chamber (bore) 45 of the casing 4A when viewed from the axial direction of the male rotor 2 as depicted in
As similar to the above, among the flow path walls defining the female-side branch flow path 73A, a second flow path wall 92A positioned outward in the radial direction of the female rotor 3 is configured to be partially and substantially flush with the female-side inner peripheral wall face 45b that is a wall face of the housing chamber (bore) 45 of the casing 4A when viewed from the axial direction of the female rotor 3 as depicted in
As similar to the first embodiment, according to the second embodiment described above, the first flow path wall 81 (male-side first flow path wall) in the male-side branch flow path 72A (male-side flow path) that opens in the rotor axial direction with respect to—the working chambers C in the suction process is formed so as to be closer to the rotor lobe section 21 (first rotor lobe section) toward the male-side termination end 76 (first termination end) side, or the first flow path wall 91 (female-side first flow path wall) in the female-side branch flow path 73A (female-side flow path) is formed so as to be closer to the rotor lobe section 31 (second rotor lobe section) toward the female-side termination end 77 (second termination end) side. This causes the flow path cross-sectional area of the male-side branch flow path 72A (male-side flow path) decreases toward the male-side termination end 76 (first termination end) side, or the flow path cross-sectional area of the female-side branch flow path 73A (female-side flow path) decreases toward the female-side termination end 77 (second termination end) side. Accordingly, the deceleration of the working fluid flowing through the male-side branch flow path 72A (male-side flow path) or the female-side branch flow path 73A (female-side flow path) is suppressed, and the acceleration loss caused by the deceleration of the working fluid flowing through the suction flow path 60A can be reduced.
In addition, in the present embodiment, when viewed from the axial direction of the male rotor 2, the second flow path wall 82A that defines the male-side branch flow path 72A (male-side flow path) and is positioned outward in the radial direction of the male rotor 2 is configured to be at least partially flush with the male-side inner peripheral wall face 45a that is a wall face of the housing chamber (bore) 45, or when viewed from the axial direction of the female rotor 3, the second flow path wall 92A that defines the female-side branch flow path 73A (male-side flow path) and is positioned outward in the radial direction of the female rotor 3 is configured to be at least partially flush with the female-side inner peripheral wall face 45b that is a wall face of the housing chamber (bore) 45.
According to this configuration, in flow components of the working fluid flowing from the male-side branch flow path 72A (male-side flow path) or the female-side branch flow path 73A (female-side flow path) toward the working chambers C, a component in the rotor radial direction less likely to be generated, and thus the pressure loss can be reduced.
In addition, in the present embodiment, when viewed from the axial direction of the male rotor 2, the second flow path wall 82A of the male-side branch flow path 72A (male-side flow path) is configured to be flush with the male-side inner peripheral wall face 45a that is a wall face of the housing chamber (bore) 45 in a range from the position of the virtual plane Pv to the male-side termination end 76 (first termination end), or when viewed from the axial direction of the female rotor 3, the second flow path wall 92A of the female-side branch flow path 73A (female-side flow path) is configured to be flush with the female-side inner peripheral wall face 45b that is a wall face of the housing chamber (bore) 45 in a range from the position of the virtual plane Pv to the female-side termination end 77 (second termination end).
According to this configuration, the flow path cross-sectional area of the male-side branch flow path 72A (male-side flow path) or the female-side branch flow path 73A (female-side flow path) becomes smaller than that in the case of the configuration of the first embodiment. This allows the amount accelerated by the male rotor 2 or female rotor 3 rotating at a high speed when sucked from the male-side branch flow path 72A (male-side flow path) or the female-side branch flow path 73A (female-side flow path) into the working chambers C to be further suppressed, so that the deterioration of the efficiency of the screw compressor due to the acceleration loss can be suppressed.
Next, a screw compressor according to a third embodiment of the present invention will be described by using
The main different point between a screw compressor 1B according to the second embodiment and the screw compressor 1 according to the first embodiment is that the shapes of a male-side branch flow path 72B and a female-side branch flow path 73B formed in a suction-side casing 42B are different in a suction flow path 60B formed in a casing 4B. Other configurations of the screw compressor 1B of the present embodiment are similar to those of the screw compressor 1 according to the first embodiment.
Specifically, among the flow path walls defining the male-side branch flow path 72B, a second flow path wall 82B positioned on a radially outer side of the male rotor 2 is configured to be partially and substantially flush with the male-side inner peripheral wall face 45a that is a wall face of the housing chamber (bore) 45 of the casing 4B when viewed from the axial direction of the male rotor 2 as depicted in
As similar to the above, among the flow path walls defining the female-side branch flow path 73B, a second flow path wall 92B positioned on a radially outer side of the female rotor 3 is configured to be partially and substantially flush with the female-side inner peripheral wall face 45b that is a wall face of the housing chamber (bore) 45 of the casing 4B when viewed from the axial direction of the female rotor 3. In details, the second flow path wall 92B is configured to be gradually closer from the radially outer side of the female rotor 3 to and then be flush with the female-side inner peripheral wall face 45b of the housing chamber (bore) 45 from the position of the virtual plane Pv toward the female-side termination end 77. The second flow path wall 92B of the present embodiment is configured to be closer to the third flow path wall 93 toward the female-side termination end 77 side. That is, as depicted in
The structures of the male-side branch flow path 72B and the female-side branch flow path 73B of the present embodiment are preferable in the case where it is difficult, due to the miniaturization of the screw compressor, to lengthen an area where the second flow path wall 82B and the second flow path wall 92B are flush with the male-side inner peripheral wall face 45a and the female-side inner peripheral wall face 45b, which are the wall faces of the housing chamber (bore) 45 of the casing 4B.
As similar to the first embodiment, according to the third embodiment described above, the first flow path wall 81 (male-side first flow path wall) in the male-side branch flow path 72B (male-side flow path) that opens in the rotor axial direction with respect to the working chambers C in the suction process is formed so as to be closer to the rotor lobe section 21 (first rotor lobe section) toward the male-side termination end 76 (first termination end) side, or the first flow path wall 91 (female-side first flow path wall) in the female-side branch flow path 73B (female-side flow path) is formed so as to be closer to the rotor lobe section 31 (second rotor lobe section) toward the female-side termination end 77 (second termination end) side. This causes the flow path cross-sectional area of the male-side branch flow path 72B (male-side flow path) decreases toward the male-side termination end 76 (first termination end) side, or the flow path cross-sectional area of the female-side branch flow path 73B (female-side flow path) decreases toward the female-side termination end 77 (second termination end) side. Accordingly, the deceleration of the working fluid flowing through the male-side branch flow path 72B (male-side flow path) or the female-side branch flow path 73B (female-side flow path) is suppressed, and the acceleration loss caused by the deceleration of the working fluid flowing through the suction flow path 60B can be reduced.
In addition, in the present embodiment, when viewed from the axial direction of the male rotor 2, the second flow path wall 82B of the male-side branch flow path 72B (male-side flow path) is configured to be gradually closer from an outer side in the radial direction of the male rotor 2 to and then be flush with the male-side inner peripheral wall face 45a, a wall face of the housing chamber (bore) 45, from the position of the virtual plane Pv toward the male-side termination end 76 (first termination end) side, or when viewed from the axial direction of the female rotor 3, the second flow path wall 92B of the female-side branch flow path 73B (female-side flow path) is configured to be gradually closer from an outer side in the radial direction of the female rotor 3 to and then be flush with the female-side inner peripheral wall face 45b, a wall face of the housing chamber (bore) 45, from the position of the virtual plane Pv toward the female-side termination end 77 (second termination end) side.
According to this configuration, the flow path cross-sectional area of the male-side branch flow path 72B (male-side flow path) or the female-side branch flow path 73B (female-side flow path) is gradually reduced toward the male-side termination end 76 (first termination end) side or the female-side termination end 77 (second termination end) side. This allows the deceleration of the working fluid flowing through the male-side branch flow path 72B (male-side flow path) or the female-side branch flow path 73B (female-side flow path) to be further suppressed.
It should be noted that the present invention is not limited to the above-described embodiments, but includes various modified examples. The above embodiments have been described in detail for the purpose of clearly explaining the present invention, and are not necessarily limited to those having all the described configurations. For example, a part of a configuration of one embodiment can be replaced by a configuration of another embodiment, or a configuration of one embodiment can be added to a configuration of another embodiment. In addition, a part of a configuration of each embodiment can be added to, deleted from, or replaced with another configuration.
For example, in the above-described embodiments, the example in which the suction port 62 of the suction flow path 60 is configured to open only in the rotor axial direction with respect to the working chambers C in the suction process has been denoted. However, the suction port can also be configured to open in the rotor radial direction with respect to the working chambers C in the suction process. However, in the case of this configuration, a leakage of the working fluid flowing into the working chambers occurs by centrifugal action through the suction port that opens in the rotor radial direction. Therefore, the configuration in which the suction port 62 opens only in the rotor axial direction is more preferable for suppressing the deceleration of the working fluid.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-040336 | Mar 2022 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2023/008100 | 3/3/2023 | WO |
