JP2012172627A - Screw compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw compressor which is capable of easily change the size of a discharging port even if the operating condition changes, in particular, a screw compressor employing a connection casing structure in which an axial port (discharging port in an axial direction) can be changed easily.SOLUTION: In the screw compressor equipped with a pair of male and female screw rotors 6a, 6b, the connection casing 1 which forms a compression part is divided at least into a rotor casing 2 around the screw rotors 6a, 6b and a discharge casing 3 on the discharging port 10 side by a dividing face 11a perpendicular to a rotor shaft 8a, and the discharge casing 3 is divided into an axial port casing part 4 which includes a face that forms the axial port and an anti rotor casing part 5 which is positioned opposite to the rotor casing 2 through the axial port casing part 4 by a dividing face 11b while the dividing faces 11a, 11b are composed in a way that they can be connected with each other.

Description

  The present invention relates to a screw compressor having a pair of male and female screw rotors that mesh with each other and adopting a connection casing structure that can easily change the size of a discharge port even if operating conditions such as a compression ratio change. .

The performance of the screw compressor greatly depends on the shape (area and shape) of the discharge port composed of so-called axial ports (discharge ports in the axial direction) and radial ports (discharge ports in the radial direction). However, the size of the discharge port in the screw compressor is usually fixed depending on the operating conditions. In other words, the size of the discharge port is determined by the design volume ratio Vi defined by the following equation (1).
Vi = V1 / V2 (1)
here,
V1: Rotor groove maximum suction volume
V2: Rotor groove final discharge volume

The relationship between the design volume ratio Vi and the design pressure ratio πi determined by the operating conditions is expressed by the following equation (2).
πi = P2 / P1 = (V1 / V2) ⁿ (2)
here,
P1: Suction pressure
P2: Final pressure in the rotor groove
n: Adiabatic index

  Therefore, if the optimum discharge port size is determined so that Pd = P2 with respect to the discharge pressure Pd, the highest efficiency can be obtained. In this way, it is desirable that the shape of the discharge port is determined according to the operating conditions of the screw compressor, but in the past, emphasis was placed on reducing the number of manufacturing steps of the casing, and the operating conditions were somewhat Even if it changed, the size of the discharge port did not change.

  However, in recent years, demands for improving the performance efficiency of compressors are increasing, and simply providing a compressor having a fixed-sized discharge port cannot meet the above-mentioned requirements. There has been a demand for a compressor that can easily change the shape of the discharge port in accordance with the operating conditions while achieving reduction.

  For example, in the application of a compressor that pumps gas from an oil field, as the buried gas is pumped out over the medium and long term, the amount of the buried gas decreases and the pressure of the pumped gas decreases. The operating conditions may deviate significantly from the conditions. Due to the difference between the initial design conditions and the operating conditions, the optimal discharge port shape cannot be secured, and thus power loss may be caused and the efficiency may be deteriorated. Further, there is a case where it is necessary to remanufacture the entire compressor unit due to insufficient power of the drive source. In order to cope with the problems as described above, there is a demand for a compressor that can easily change the shape of the discharge port.

  A conventional example in which the shape of the discharge port can be easily changed under such a technical background will be described below with reference to FIGS. FIG. 6 is an explanatory view of the discharge port of the screw compressor according to the conventional example 1, and FIG. 7 is a plan sectional view showing the casing configuration of the screw compressor according to the conventional example 2, omitting the screw rotor.

  First, as shown in FIG. 6, as the screw compressor according to the conventional example 1, the radial discharge port 19a is formed by thin-wall casting, and the thin-wall portion can be excised when used at a low pressure ratio and high-speed rotation. Has been proposed. Thereby, since the size of the discharge port 19a can be easily optimized, it is said that high efficiency can be obtained with a single casting casing under a wide range of operating conditions (see Patent Document 1).

However, although the discharge port 19a of the screw compressor according to the conventional example 1 is reduced in the number of manufacturing steps as compared with the prior art prior to the conventional example 1, the thin wall portion of the discharge port formed at the time of casting. The manufacturing process of cutting out (thickness h ₂ ) according to operating conditions is still subjected to a great processing and manufacturing load, and while reducing manufacturing man-hours, depending on the operating conditions, The demand for a compressor that can easily change the size of the discharge port has not been fully met.

  The problem with the screw compressor according to the above-described conventional example 1, that is, “sufficiently meets the demand for a compressor that can easily change the size of the discharge port according to operating conditions while reducing the number of manufacturing steps. As a solution to the problem “not cut”, a screw compressor according to Conventional Example 2 shown in FIG. 7 has been proposed. In the screw compressor according to Conventional Example 2, the casing 21 that houses the screw rotor is divided into a discharge port vicinity portion 26 including at least the discharge port 26a and other portions 22a other than the discharge port vicinity portion 26. The discharge port vicinity portion 26 is configured to be detachable from the other portion 22a (see Patent Document 2).

  As a result, the vicinity of the discharge port 26 can be replaced according to the operating conditions, so that it is possible to save energy by minimizing the power, and it is not necessary to manufacture the entire casing 21 as in the prior art. The time required for this is shortened and the cost can be reduced.

  However, in this conventional example 2, the casing 21 for housing the screw rotor is divided into a discharge port vicinity portion 26 including at least the discharge port 26a and another portion 22a other than the discharge port vicinity portion 26, and Although it has been proposed that the vicinity of the discharge port 26 is configured to be detachable from the other portion 22a, as an embodiment, the rotor casing 22 around the screw rotor, the discharge casing 24 on the discharge port 26a side, and the suction port 23a. The rotor casing 22 is divided into three parts, or a part of the rotor casing 22 can be further divided, or the suction casing 23 and a discharge / rotor casing (not shown) are divided into two parts. -Only a part of the rotor casing that can be divided is specified.

  According to the embodiment disclosed in Patent Document 2, the latter of the two ports forming the discharge port 26a described above, namely, the axial port (axial discharge port) and the radial port (radial discharge port). However, the former change is not always easy. For example, it has not been possible to meet the demand for adopting a conventional shape only for the radial port (radial outlet) and adopting an axial port (axial outlet) having a shape different from the conventional one.

JP-A-7-208362 JP 2010-191970 A

  Accordingly, an object of the present invention is to provide a screw compressor that can easily change the size of the discharge port even if the operating conditions change while reducing the number of manufacturing steps, and in particular, an axial port (axial discharge port). An object of the present invention is to provide a screw compressor that employs a connection casing structure that can be easily changed.

  In order to achieve the above object, the screw compressor according to claim 1 of the present invention employs a screw compressor having a pair of male and female screw rotors that mesh with each other, and the screw is separated by a dividing surface perpendicular to the rotor axis. The connecting casing that houses the rotor and forms the compression portion is divided into at least a rotor casing around the screw rotor and a discharge casing on the discharge port side, and the discharge casing includes an axial surface that forms an axial port. While being divided into a port casing part and an anti-rotor casing part located on the opposite side of the rotor casing via the axial port casing part, these divided surfaces are configured to be connectable to each other. It is what.

  The means adopted by the screw compressor according to claim 2 of the present invention is the screw compressor according to claim 1, wherein an excavation portion is formed on the discharge port end face of the axial port casing part. An end plate is detachably attached to the part.

  The means adopted by the screw compressor according to claim 3 of the present invention is a screw compressor having a pair of male and female screw rotors that mesh with each other, and the compression rotor is accommodated by a dividing surface orthogonal to the rotor shaft. The connecting casing to be formed is divided into at least a rotor casing around the screw rotor and a discharge casing on the discharge port side, and these divided surfaces are configured to be mutually connectable to the discharge port end surface of the discharge casing. A digging portion is formed, and an end plate is detachably attached to the digging portion.

  According to the screw compressor according to claim 1 of the present invention, in the screw compressor having a pair of male and female screw rotors meshing with each other, the screw rotor is housed by the dividing surface orthogonal to the rotor shaft to form the compression portion. The connecting casing is divided into at least a rotor casing around the screw rotor and a discharge casing on the discharge port side, and the discharge casing includes an axial port casing portion including a surface forming an axial port, and the axial port casing. While being divided into the opposite rotor casing part located on the opposite side of the rotor casing via the part, these divided surfaces are configured to be mutually connectable.

  As a result, even when the operating conditions change and it is necessary to change the size and the axial port of the discharge port, the size and shape of the discharge port and the axial port can be changed by replacing only the axial port casing part. In addition, the size and weight of the casing to be replaced can be greatly reduced, and the number of machining points is small, so that the cost and time required for remanufacturing can be greatly reduced.

  Moreover, according to the screw compressor which concerns on Claim 2 of this invention, a digging process part is formed in the discharge port end surface of the said axial port casing site | part, and an end plate is attached to this digging process part so that attachment or detachment is possible. It becomes.

  As a result, even when the operating conditions change and it is necessary to change the size and axial port of the discharge port, only the end plate can be replaced to change the size and shape of the discharge port, particularly the axial port. Therefore, the replacement of the casing is unnecessary, the size and weight of the part to be replaced can be significantly reduced, and the number of processing parts is also small, so that the cost and time required for remanufacturing can be greatly reduced.

  According to the screw compressor of claim 3 of the present invention, in the screw compressor having a pair of male and female screw rotors that mesh with each other, the screw rotor is housed by the dividing surface orthogonal to the rotor shaft, and the compression portion is provided. The connecting casing to be formed is divided into at least a rotor casing around the screw rotor and a discharge casing on the discharge port side, and these divided surfaces are configured to be mutually connectable to the discharge port end surface of the discharge casing. A digging portion is formed, and an end plate is detachably attached to the digging portion.

  As a result, as in the case of the screw compressor according to claim 2 of the present invention, even when the operating condition changes and the size of the discharge port or the axial port needs to be changed, only the end plate is replaced, The size and shape of the exit, especially the axial port, can be changed. Therefore, the replacement of the casing is unnecessary, the size and weight of the part to be replaced can be significantly reduced, and the number of processing parts is also small, so that the cost and time required for remanufacturing can be greatly reduced.

It is a front sectional view which shows the casing structure of the screw compressor which concerns on Embodiment 1 of this invention. It is a sectional side view of an axial port casing part concerning Embodiment 2 of the present invention. FIG. 5 is a side cross-sectional view according to the second embodiment of the present invention and showing an arrow BB in FIG. 2. It is a front sectional view which shows the casing structure of the screw compressor which concerns on Embodiment 3 of this invention. FIG. 10 is a side sectional view of an axial port casing portion, according to the third embodiment of the present invention, showing an enlarged view CC in FIG. 4. It is explanatory drawing of the discharge port of the screw compressor which concerns on the prior art example 1. FIG. It is the plane sectional view which showed the casing composition of the screw compressor concerning conventional example 2, and omitted the screw rotor.

  First, a screw compressor according to Embodiment 1 of the present invention will be described below with reference to FIG. 1 is a front sectional view showing a casing configuration of a screw compressor according to Embodiment 1 of the present invention. 1 is a substantially vertical cross section passing through the approximate center of the axis of the male rotor 6a, and below the line DD in FIG. A substantially vertical cross section passing through the center is shown.

  In the screw compressor according to Embodiment 1 of the present invention, a pair of male and female screw rotors 6a and 6b mesh with each other and are rotatably accommodated in a rotor chamber 7 formed inside a rotor casing 2 described later. Only one of the pair of male and female screw rotors 6a and 6b, only the rotor shaft 8a of the male rotor 6a, is connected to a drive shaft of a drive motor (not shown).

  The female rotor 6b rotates following the male rotor 6a, forms a compression space in the gap between the male rotor 6a and the female rotor 6b, and rotates the screw rotors 6a and 6b with the drive motor, thereby sucking the flow of suction. The gas supplied from the passage 9a is sucked from the suction port 9 of the compressor, compressed, and discharged from the discharge port 10 to the discharge flow path 10b as a high-pressure fluid.

  In the screw compressor according to Embodiment 1 of the present invention, the connection casing 1 that houses the screw rotors 6a and 6b and forms the compression portion is at least provided by the split surface 11a orthogonal to the rotor shaft 8a. , 6b is divided into two parts: a rotor casing 2 that forms the rotor chamber 7 around the periphery, and a discharge casing 3 that forms the discharge port 10.

  At the same time, the discharge casing 3 includes a discharge port in the direction of the rotor shaft 8a of the discharge port 10, that is, a surface that forms an axial port 10a shown in FIG. 2, which will be described later, by another divided surface 11b orthogonal to the rotor shaft 8a. It is divided into an axial port casing part 4 and an anti-rotor casing part 5 located on the opposite side of the rotor casing 2 via the axial port casing part 4. Therefore, the casing 1 of the compression part is divided into three parts, a rotor casing 2, an axial port casing part 4 and an anti-rotor casing part 5.

  The dividing surface 11a on the side of the discharge casing 3 that divides the rotor casing 2 and the discharge casing 3 faces the left end surface of the rotor 6a, 6b in the rotor chamber 7 of FIG. 1 (formation surface of the axial port 10a to the rotor chamber 8). ). Then, the rotor casing 2, the axial port casing part 4 and the anti-rotor casing part 5 divided into three parts are brought into contact with each other on the divided surfaces 11a and 11b, and are connected by a plurality of studs 12a and nuts 12b to be compressed. The connection casing 1 of the part is comprised.

  Even if it becomes necessary to change the size of the discharge port 10 or the axial port 10a by changing the operating conditions by configuring the connection casing 1 of such a screw compressor, only the axial port casing portion 4 is provided. The size and shape of the discharge port 10 and the axial port 10a can be changed by replacement. In addition, the size and weight of the casing to be replaced can be greatly reduced, and the number of processing points is small, so that the cost and time required for remanufacturing can be greatly reduced.

Next, a screw compressor according to Embodiment 2 of the present invention will be described below with reference to FIGS. 2 is a side sectional view of an axial port casing portion according to a second embodiment of the present invention, and FIG. 3 is a side sectional view showing an arrow BB in FIG. . Here, FIG. 1 relates to the first embodiment of the present invention and is not related to the second embodiment of the present invention, but FIG. 2 according to the second embodiment of the present invention is, as it is, an arrow A in FIG. It is a figure according to what expanded and showed -A.
The second embodiment of the present invention is different from the first embodiment in the configuration of the discharge port end surface of the axial port casing part, and the other components are completely the same. The explanation will be stopped.

  That is, in the first embodiment of the present invention, the connection casing 1 includes at least the rotor casing 2 that forms the rotor chamber 7 around the screw rotors 6a and 6b by the dividing surface 11a orthogonal to the rotor shaft 8a. The discharge casing 3 is divided into two parts, the discharge casing 3 forming the outlet 10, and the discharge casing 3 is divided into an axial port casing part 4 and an anti-rotor casing part 5 by a dividing surface 11b orthogonal to the rotor shaft 8a. At the same time, the divided surfaces 11a and 11b are configured to be connectable to each other.

  On the other hand, in the second embodiment of the present invention, as in the first embodiment of the present invention, the connecting casing 1 is a rotor casing around the screw rotors 6a and 6b by the divided surfaces 11a and 11b orthogonal to the rotor shaft 8a. 2, an axial port casing part 4 on the discharge port 10 side, and an anti-rotor casing part 5.

  Further, as shown in FIG. 3, digging portions 13a and 13b having a depth of about 10 mm are formed around the screw shafts 8a and 8b at the end face of the discharge port 10 (axial port 10a) of the axial port casing portion 4. The end plates 14a and 14b, which can change the opening size by closing a part of the discharge port 10 (axial port 10a), are fitted in the engraved portions 13a and 13b, and hexagon socket head bolts 15 and 15 etc. Is detachably attached.

  As a result, even if the operating conditions change and the size of the discharge port 10 or the axial port 10a needs to be changed, only the end plates 14a and 14b are replaced, and the size of the discharge port 10 or the axial port 10a is changed. The shape can be changed. Therefore, it is not necessary to replace the connection casing 1, the size and weight of the replacement part can be greatly reduced, and the number of parts to be processed can be reduced, so that the cost and time required for remanufacturing can be greatly reduced.

Next, a screw compressor that employs a connection casing structure according to Embodiment 3 of the present invention will be described below with reference to FIGS. 4 and 5 and FIG. FIG. 4 is a front sectional view showing a casing configuration of a screw compressor according to Embodiment 3 of the present invention. FIG. 5 is a side sectional view of an axial port casing portion showing the enlarged view CC of FIG. 4 according to the third embodiment of the present invention.
Note that the third embodiment of the present invention differs from the second embodiment described above in that the configuration of the discharge casing 3a is different, and the other configuration is exactly the same.

  That is, in Embodiment 2 of the present invention (and also in Embodiment 1 of the present invention), the connecting casing 1 is at least a rotor around the screw rotors 6a and 6b by the dividing surface 11a orthogonal to the rotor shaft 8a. The rotor casing 2 forming the chamber 7 and the discharge casing 3 forming the discharge port 10 are divided into two, and the discharge casing 3 is divided into the axial port casing portion 4 by the dividing surface 11b orthogonal to the rotor shaft 8a. And the anti-rotor casing portion 5 and the divided surfaces 11a and 11b are configured to be connectable to each other.

  On the other hand, in the third embodiment of the present invention, the discharge casing 3a is not divided into an axial port casing part and an anti-rotor casing part, but is constituted by a single casing. Therefore, macroscopically, the casing 1 of the compression part is divided into two parts, a rotor casing 2 and a discharge casing 3a.

  However, the configuration of the end surface of the discharge port of the discharge casing 3a in the third embodiment of the present invention is the same as the configuration of the end surface of the discharge port 10 of the axial port casing portion 4 in the second embodiment of the present invention.

  That is, similarly to FIG. 3, digging portions 13a and 13b having a depth of about 10 mm are formed around the screw shafts 8a and 8b on the end face of the discharge port 10 (axial port 10a) of the discharge casing 3a. End plates 14a and 14b, which can change the opening size by closing a part of the discharge port 10 (axial port 10a), are fitted in the machining portions 13a and 13b, and can be attached and detached with hexagon socket bolts 15 and 15 or the like. Is attached.

  As a result, even if the operating conditions change and the size of the discharge port 10 or the axial port 10a needs to be changed, only the end plates 14a and 14b are replaced, and the size of the discharge port 10 or the axial port 10a is changed. The shape can be changed. Therefore, it is not necessary to replace the connection casing 1, the size and weight of the replacement part can be greatly reduced, and the number of parts to be processed can be reduced, so that the cost and time required for remanufacturing can be greatly reduced.

1: Connection casing,
2: Rotor casing,
3, 3a: discharge casing,
4: Axial port casing,
5: Anti-rotor casing,
6a: male rotor (screw rotor), 6b: female rotor (screw rotor),
7: Rotor chamber,
8a, 8b: rotor shaft,
9: Suction port, 9a: Suction flow path,
10: Discharge port, 10a: Axial port, 10b: Discharge flow path,
11a, 11b: division planes,
12a: stud bolt, 12b: nut,
13a, 13b: excavation processing part,
14a, 14b: end plate,
15: Hexagon socket head cap screw

Claims (3)

In a screw compressor having a pair of male and female screw rotors that mesh with each other,
By the dividing plane perpendicular to the rotor axis,
The connection casing that houses the screw rotor and forms the compression portion is divided into at least a rotor casing around the screw rotor and a discharge casing on the discharge port side,
While the discharge casing is divided into an axial port casing part including a surface forming an axial port, and an anti-rotor casing part located on the opposite side of the rotor casing via the axial port casing part,
A screw compressor characterized in that these divided surfaces are configured to be mutually connectable.   The screw compressor according to claim 1, wherein a digging portion is formed on an end surface of the discharge port of the axial port casing portion, and an end plate is detachably attached to the digging portion. In a screw compressor having a pair of male and female screw rotors that mesh with each other,
By the dividing plane perpendicular to the rotor axis,
The connection casing that houses the screw rotor and forms the compression portion is divided into at least a rotor casing around the screw rotor and a discharge casing on the discharge port side,
These split surfaces are configured to be connectable to each other,
A screw compressor, wherein a digging portion is formed on a discharge port end face of the discharge casing, and an end plate is detachably attached to the digging portion.

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