JPH0460191A - Silencing structure of screw compressor - Google Patents

Abstract

PURPOSE:To improve silencing performance and miniaturization by providing many irregularities or many baffleplates in an internal surface of a delivery pipe, connected to a delivery port of a compressor main unit, and forming this internal surface of porous material. CONSTITUTION:In an oil-cooled screw compressor, an oil separator collector 14 is connected to a delivery port 12 of a compressor main unit 11 through a delivery pipe 13, and a silencing structure l is formed by providing many irregularities 2 in an internal surface of a delivery pipe 13. In the case of compressing gas, sucked from a suction port 15 by a screw rotor 18, to be delivered with oil, injected into a rotor chamber 17 for a purpose of cooling or the like, to the delivery pipe 13 via the delivery port 12, noise is reduced by damping pressure pulsation of a gas/liquid mixture phase through fluidizing friction or the like between this gas/liquid mixture phase and the irregularities 2. The silencing structure l may be constituted formed by providing many baffleplates in the inside of the delivery pipe 13 and by forming the internal surface of the delivery pipe 13 of porous material consisting of, for instance, sintered metal.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a noise reduction structure for a screw compressor connected to a discharge port of a compressor main body.

(Prior Art) In recent years, user demands for lower noise from screw compressors have been increasing in order to improve the working environment.

Therefore, conventionally, as a sound damping structure for a screw compressor, a sound damping device with a member having at least one constricted part is attached to the suction port or the discharge port (Japanese Patent Laid-Open No. 54-54
309 (Japanese Patent Application Laid-open No. 56-54987), and one in which a flat muffler forming a silencing chamber is interposed in a gas flow path in a high-pressure chamber following the discharge port side (Japanese Patent Laid-Open No. 56-54987) has been proposed.

(Problems to be Solved by the Invention) In any of the above conventional devices, the performance of the sound deadening structure and its volume are closely related, and if the performance is to be improved, a large space is inevitably required. It had become. However, there is also a strong demand from users to minimize the space occupied, and there has been a desire for the development of a compact and high-performance sound deadening structure.

The present invention has been made in response to the above-mentioned needs, and aims to provide a screw compressor that has improved noise reduction performance and can be made smaller.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a large number of unevenness or a large number of baffle plates on the inner surface of the discharge pipe connected to the discharge port of the compressor main body, Alternatively, the inner surface is made of a porous material.

(Function) By forming the structure as described above, pressure pulsations in the gas-liquid multiphase flow occur due to friction with the inner wall surface of the pipe during the process in which the gas-liquid multiphase flow of discharged gas and oil from the compressor body passes through the inside of the pipe, which has an uneven inner surface. is attenuated.

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

FIG. 1 shows an oil-cooled screw compressor to which a noise reduction structure I according to a first embodiment of the present invention is applied. The side end portion is connected to the oil separation and recovery device 14. The muffling structure 1 is formed by providing a large number of projections and depressions 2 on the inner surface of a discharge pipe 13, and the discharge pipe 13 is preferably flexible. Here, the compressor main body 11 has a rotor chamber I7 of a casing 16 which has one side opened to the suction port 15 and the other side opened to the discharge port I2.
The screw rotor 18 is rotatably housed therein. In addition, there is one air pocket above the oil level in the oil separation and recovery device 14, and the inlet side of the outlet 20 is filled with oil M.
Collection element 2J is attached.

Then, the screw rotor 18 compresses the gas sucked in from the suction port 15 and discharges it into the discharge pipe 13 through the discharge port 12 together with the oil injected into the rotor chamber 17 for the purpose of cooling, etc., and this gas-liquid mixture is created. It is formed so as to attenuate the pressure pulsation of the gas-liquid mixed phase by the flow friction between the above-mentioned unevenness 2 and reduce the noise. That is, the pressure pulsations of the discharged gas in the discharge pipe I3 are weakened, thereby weakening the pressure pulsations in the air reservoir 19, thereby reducing the noise leaking outside the machine. Note that the discharged gas is separated from the oil discharged together by the oil separation element 21 and sent out from the outlet section 20, while the oil is made to drip into the oil reservoir section 22 below.

Next, FIGS. 2 and 3 showing actual measurement results regarding noise will be explained.

Figure 2 shows the pressure pulsations in the air pocket above the oil level when the connection part of the discharge pipe with the oil separator and recovery device is above the oil level, that is, when neither cross section of the discharge pipe is filled with oil. Actual Measurement Results: FIG. 3 shows actual measurement results of pressure pulsations in the air pocket 19 of the above embodiment, in which the horizontal axis represents frequency and the vertical axis represents sound pressure level, abbreviated as SPL. In addition, the operating conditions for the screw compressor are that the rotation speed of the male rotor (number of teeth: 4) is 5°, 500 rpm, and the discharge pressure is 8 kg/cm. Note that the X mark in Figure 1 indicates the measurement position. There is.

The peak parts at frequencies a, ..., e in Figure 2 have SPL values of 138.125, 138, 127, 128, respectively.
(dB) was 123°11 in Figure 3.
4.223,116. IJCI (dB) and significantly (approximately 1
0 dB).

FIG. 4 and FIG. 5 show the silencing structures 1a and 1b according to the second and third embodiments of the present invention, which are shown in FIG.

Among these, the silencing structure 1a shown in FIG. 4 is formed by providing a large number of baffle plates 3 inside the discharge pipe 13, and the silencing structure ib shown in FIG. It is formed from a porous material 4 made of a compact metal.

(Effects of the Invention) As is clear from the above description, according to the present invention, a large number of unevenness or a large number of baffle plates are provided on the inner surface of the discharge pipe connected to the discharge port of the compressor main body, or The inner surface is made of porous material.

Therefore, in the process of the discharged gas-liquid mixed phase flow passing through the above-mentioned discharge pipe, the pressure pulsations of the gas-liquid mixed phase flow are attenuated due to friction with the pipe inner wall surface, etc., and the pressure after passing through this part is reduced. As a result of the significantly reduced pulsation, it is possible to reduce the noise of the device, and the silencing structure itself can be made smaller, resulting in the effect that the space occupied by the device can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an oil-cooled screw compressor to which a noise reduction structure according to a first embodiment of the present invention is applied, and FIG. FIG. 3 is a diagram showing actual measurement results of sound pressure level, and FIG. FIG. 5 shows the second embodiment of the present invention. FIG. 7 is a sectional view of a sound deadening structure according to a third embodiment. lja, lb...silencing structure, 2...irregularities, 3...
Baffle plate, 4... Porous material, 11... Compressor main body, 1
3...Discharge pipe. Figure 1 Figure 4 Figure 5 In', Figure 2 Figure 3 Frequency (Hz)

Claims (1)

[Claims] (1) Screw compression characterized in that the inner surface of the discharge pipe connected to the discharge port of the compressor main body is provided with a large number of irregularities, a large number of baffles, or the inner surface is made of a porous material. The machine's sound deadening structure.