JP2704039B2 - Screw compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an oil-cooled and oil-free screw compressor.

(Prior Art) In recent years, there has been an increasing demand from users for noise reduction of a screw compressor in order to improve a working environment.

Therefore, as a conventional noise reduction structure of a screw compressor, a noise reduction device in which at least one member having a throttle portion is interposed is attached to a suction port or a discharge port (JP-A-54-5430).
Japanese Patent Application Laid-Open No. 56-54987), and a device in which a flat muffler for forming a muffling chamber is interposed in a gas flow path in a high-pressure chamber following the discharge port side.

(Problems to be Solved by the Invention) In any of the above-mentioned conventional devices, the performance of the silencing structure and its volume are closely related, and in order to improve the performance, a large space is necessarily required. Had become. However, there is a strong demand from users to reduce the occupied space,
It has been desired to develop a compact and high-performance silencing structure.

SUMMARY OF THE INVENTION The present invention has been made to meet the above-described demands, and has as its object to provide a screw compressor capable of improving noise reduction performance and reducing its size.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a discharge port having a cross-sectional area perpendicular to the discharge direction of a discharge gas as compared with the opening area of the discharge port. A wider bulging space and a small cross-section flow path in which the discharge gas flowing into the bulging space from the discharge port is changed in L direction to flow therethrough are formed in the same casing as the screw rotor.

(Operation) By forming as described above, the compressed gas discharged from the discharge port hits the inner wall of the casing when changing the flow direction to the L-shape.
After that, the gas flow resistance changes due to the narrowing, and the reflection of the gas molecules occurs, so that the sound is difficult to propagate, and it is not necessary to provide a separate silencer outside the casing, so that the whole apparatus is downsized.

(Example) Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a screw compressor according to a first embodiment of the present invention, which is continuously connected to a discharge port 4 of a casing 3 which rotatably accommodates a pair of male and female screw rotors 1 and 2 meshing with each other and arranged in parallel in the vertical direction. In FIG. 1, a swelling space 5 is formed laterally from the discharge port 4. Following the bulging space 5, a small section flow path 6 is formed in the same casing 3 as the screw rotors 1 and 2 along the wall of the rotor chamber in which the screw rotors 1 and 2 are housed vertically. . Here, the expression “small cross section” is used in the sense that the flow path cross section is discontinuously smaller than that in the bulging space 5.

Then, the compressed gas is discharged from the discharge port 4 to the bulging space 5 having a large volume and collides with the wall portion,
After the direction is changed, the sound is guided to the small-section flow path 6 having a smaller cross-sectional area, thereby weakening the sound propagation and reducing the noise. That is, the compressed gas is made to collide with the wall portion, and by changing the flow path cross-sectional area of the compressed gas, the flow resistance of the gas is changed, and the reflection of gas molecules is caused to weaken the propagation of sound. I have.

Further, by forming the small-section flow path 6 from the bulging space 5 along the wall of the rotor chamber in the same casing 3 as the screw rotors 1 and 2, the entire device is compared with the case where a noise reduction structure is separately provided. It is small.

In the case of an oil-cooled compressor, an oil tank (not shown) is provided below the casing 3 for separating and recovering the oil discharged together with the compressed gas. In this case, as shown by a two-dot chain line, It is preferable to provide a small tube 7 having a smaller cross section in the small cross section flow path 6 so as to extend into the oil tank in order to reduce noise.

FIG. 2 shows a screw compressor according to a second embodiment of the present invention, in which a pair of male and female screw rotors 1 and 2 which are arranged side by side and are in mesh with each other (only one of the two is shown in the drawing). 2), a swelling space 5 is formed in the vertical direction from the discharge port 4 in FIG. Subsequent to the bulging space 5, a small-section flow path 6 is formed in the same casing 3 as the screw rotors 1 and 2 along with the bulging space 5 in the lateral direction as in the first embodiment.

With this configuration, noise is reduced by the same operation as in the first embodiment, and the entire device is made compact.

When the apparatus is of an oil-cooled type, as in the case of the first embodiment, as shown by a two-dot chain line, it is extended to the inside of an oil tank (not shown) following the small-section flow path 6. Preferably, a capillary 7 is provided.

(Effects of the Invention) As is clear from the above description, according to the present invention, the cross-sectional area continuous to the discharge port and perpendicular to the discharge direction of the discharge gas is larger than the opening area of the discharge port. The enlarged bulging space and a small cross-section flow path in which the discharge gas flowing from the discharge port into the bulging space is changed in L direction to flow therethrough are formed in the same casing as the screw rotor.

For this reason, when the compressed gas discharged from the discharge port hits the inner wall of the casing and the cross-sectional area of the flow path changes, the flow resistance of the gas changes, the reflection of gas molecules occurs, the sound becomes difficult to propagate, and the noise is reduced. Can be reduced.

In addition, since the swelling space and the small cross-section flow path are provided in the same casing as the screw rotor, there is an effect that the entire device can be downsized.

[Brief description of the drawings]

FIG. 1 is a sectional view of a screw compressor according to a first embodiment of the present invention, and FIG. 2 is a sectional view of a screw compressor according to a second embodiment of the present invention. 3 ... casing, 4 ... discharge port, 5 ... bulging space, 6 ... small section flow path.

Claims (1)

(57) [Claims] A bulging space which is continuous with the discharge port and whose cross-sectional area perpendicular to the discharge direction of the discharge gas is larger than the opening area of the discharge port; A screw compressor characterized in that a small cross-section flow path in which a discharge gas flowing into a space is changed in direction into an L-shape and provided in the same casing as a screw rotor.