JPH01107077A - Refrigerator - Google Patents

Abstract

PURPOSE: To prevent a resonant sound of a muffler from being produced by disposing a secondary muffler having a primary resonant frequency 2/3 times that of the muffler between the muffler demonstrating resonance. CONSTITUTION: A muffler 6 serving to prevent high temperature freezer oil from returning to an evaporator 4 from a compressor 1 for a refrigerant circuit is disposed between the compressor 1 and the evaporator 4 together with an accumulator 5. A secondary muffler 9 having a first resonant frequency 2/3 times a primary resonant frequency of the muffler 6 is disposed between the compressor 1 and the muffler 6 through connection pipes 7, 8. Hereby, with the muffler and the second muffler pressure pulsation of a resonant frequency component can be attenuated, and hence a resonant sound of the muffler can be prevented from being occurred.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a refrigerator, and particularly to prevention of resonance noise generated during operation of the refrigerator.

[Conventional technology]

FIG. 3 is a refrigerant circuit diagram of a well-known refrigerator shown in, for example, Japanese Utility Model Application Publication No. 58-54053. In the figure, 11
) is a compressor, which is connected in series with a condenser (2), a throttle section (3), and an evaporator (4) to form a well-known refrigerant circuit. (5) is an accumulator for storing liquid refrigerant, and (6) is a muffler for preventing high temperature oil and refrigerant from flowing back from the compressor to the evaporator during stoppage. Evaporator(
4).

(7) is a suction pipe that connects this muffler and the compressor (1).

Next, the operation will be explained.

The refrigerant compressed by the compressor +11 is condensed in the condenser (2).

The pressure is reduced in the throttle section (3) and evaporated in the evaporator (4) to form a refrigeration cycle. Also, since the amount of refrigerant circulating changes due to changes in the outside temperature, excess refrigerant is stored in the accumulator (5
). Furthermore, when the compressor stops, high-pressure refrigerant gas and oil flow back from the compressor Il+ due to the pressure difference between high and low pressures and accumulate in the muffler (6).

[Problem that the invention seeks to solve]

Conventional refrigerators are constructed as described above, so the pressure pulsations of the compressor during operation cause gas resonance within the muffler, and this vibration is transmitted through the piping and radiated into the atmosphere as noise from the refrigerator cabinet. There was a problem that the

This invention was made in order to solve the above-mentioned problems, and an object thereof is to obtain a refrigerator that does not generate muffler resonance noise.

[Means for solving problems]

The refrigerator according to the present invention includes a secondary muffler whose primary resonance frequency is two-thirds of the primary resonance frequency of the muffler, between the muffler and the compressor.

[For production]

In the refrigerator according to the present invention, the two mufflers mutually attenuate the pressure pulsation waves of the resonant frequency components of the other muffler, thereby reducing the excitation force transmitted to the cabinet and preventing the generation of gas resonance noise.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

In Figure 1, +11 is a compressor, (21 is a condenser,
(3) is a throttle section, and 14) is an evaporator, which are connected in series to form a refrigerant circuit. (5) is an accumulator for storing liquid refrigerant, and (6) is a muffler for preventing high temperature refrigerating machine oil from returning from the compressor 11) to the evaporator (4).
) and the evaporator (4). (9) is a secondary muffler having a primary resonance frequency that is 2/3 of the primary resonance frequency of this muffler, and is connected to the compressor 11) and the muffler (
6) is connected with connecting pipes +71 and +81.

If these mufflers (6) have a 9-cylindrical shape and both end faces are perpendicular to the axis, the primary resonance frequency of the secondary muffler (9) is the -order resonance frequency of the muffler (6). In order to make it 2/3 of fa, the length should be 1.5 times the half wavelength at that frequency fo, as shown in the graph of the relationship between transmission loss and frequency shown in Figure 3. In order to connect the muffler to the suction pipes +71 to +81 in the middle of the refrigeration circuit, both ends of the muffler are formed into a tapered shape by drawing as shown in FIG.

Later, the incident wave A of the muffler having a tapered part at the end
The ratio between i and the transmitted wave AO can be obtained from the following formula.

Here, t: Cylindrical length s te” Taper length = ω
/a, ω: Angular frequency a: Sound speed m = S 2/
S 1, S 1: Cross-sectional area of entrance/exit part S2 Two cylindrical part cross-sectional area Therefore, the transmission loss TL is, so this can be calculated as muffler (6) and secondary muffler (7).
), the specific dimensions of the muffler adopted in the embodiment of this invention are as follows.

That is, the muffler (6) has t=17mm, t
e=20 drunkenness, S2=1379w1. S, = 22.5
- and has a primary resonance frequency of 2180Hz at a sound speed of 150m/s, and the secondary muffler (7) has t=46.
5. te=6.5°S,=22.5-,S2=24
Since it has a primary resonance frequency of 1430 Hz at a sound speed of 0.5-150 m/s, it is 2/3 of that of the muffler (6).

Next, the effect will be explained. When the compressor (1) operates, the refrigerant gas is compressed, condensed in the condenser (2), and passed through the throttle section (
The pressure is reduced in step 3) and evaporated in the evaporator (4) to form a refrigeration cycle. At this time, high-pressure gas and oil from the compressor leak to the low-pressure side, transmitting high-frequency pressure pulsating waves into the suction pipe. This pulsating wave is attenuated in the secondary muffler (91) due to the transmission loss of this secondary muffler (91),
The resonance frequency component of 9) remains and is transmitted to the suction pipe (7),
It is transmitted to the muffler (6). Since the muffler (6) has a primary resonance frequency that is 1.5 times that of the secondary muffler (9), the transmission loss of the muffler +61 at the secondary muffler's resonance frequency is large, and therefore the pulsating waves are attenuated here. Therefore, the force that excites the cabinet is reduced, and the resonance sound of the secondary muffler +91 is no longer produced. Further, as described above, the resonance frequency component of the muffler (6) is attenuated by the secondary muffler (9), so that the muffler (6) does not generate any resonance sound.

Fig. 4 shows the results of a comparative test using a conventional refrigerator and an actual refrigerator having a refrigeration circuit equipped with a secondary muffler +91 according to the present invention. However, in the device according to the present invention, it becomes a flat part (b) as shown by the dotted line.

This indicates that the muffler (6) is making a resonant sound.

5 and 6 show other embodiments of the present invention, in which the length of the suction pipe (7) between the muffler (6) and the secondary muffler (9) is adjusted to the length of the muffler (6). It is an integer multiple of 1/2 of the wavelength of the primary resonance frequency, and the secondary muffler (9
) is the primary of the muffler (6) between the suction pipes (7) and (8) using a connecting pipe a1 whose inner diameter is greater than the outside diameter of the suction pipe.

The connection may be made so that the wavelength is 1.5 times the half wavelength of the resonant frequency. In this case, the difference in boundary conditions between the inside of the connecting pipe fIll and the outlet of the suction pipe (7) prevents the formation of a standing wave at the frequency of the muffler (6), so that the same effect as described above is obtained.

〔Effect of the invention〕

As described above, according to the present invention, a secondary muffler having a primary resonant frequency of two-thirds of the muffler is disposed between the muffler that causes resonance and the compressor, so that each muffler has a resonant frequency of the other. It is possible to attenuate component pressure pulsation waves and prevent the generation of muffler resonance noise.

[Brief explanation of the drawing]

Fig. 1 is a refrigerant circuit diagram of a refrigerator according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of a muffler, Fig. 3 is a relationship diagram between transmission loss and frequency, and Fig. 4 is a conventional device and a refrigerator according to the present invention. 5 is a refrigerant circuit diagram corresponding to FIG. 1 showing another embodiment of the present invention, FIG. 6 is an enlarged sectional view of the main part of FIG. 5, and FIG. 7 is a diagram of a conventional refrigerator. It is a refrigerant circuit diagram. (11 is the compressor, (2) is the condenser, (3) is the throttle part, (
4) is an evaporator, (5) is an accumulator, (6) is a muffler, (7) and (8) are suction pipes, and (9) is a secondary muffler. Note that the same reference numerals in Figure 1 indicate the same or equivalent parts.

Claims (2)

[Claims] (1) In a refrigerator equipped with a refrigeration cycle in which a compressor, a condenser, a throttle section, and an evaporator are sequentially connected in series, and an accumulator and a muffler are connected between the evaporator and the compressor, the muffler and the compressor are connected together. A refrigerator comprising a secondary muffler whose primary resonance frequency is 2/3 of the primary resonance frequency of the muffler. (2) The refrigerator according to claim 1, wherein the pipe connecting the muffler and the secondary muffler is set to have a length that is an integral multiple of a half wavelength of the primary resonance frequency of the muffler.