A vibration-damping common base for ship chillers

Abstract

The present invention relates to a vibration reduction common base for a ship chiller, which is composed of an iron frame, an anti-resonance beam, a damping filler, a condenser foot mounting plate, and a vibration isolator. The iron frame is the main structure of the vibration reduction common base, which is used to carry and install all components. The iron frame leaves a space in the form of a well directly below the condenser for the installation of the anti-resonance beam; the anti-resonance beam is a group of detachable or semi-detachable component beams, whose length direction is consistent with the axial direction of the condenser, and the two ends are fixed on the walls at both ends of the well of the iron frame; the anti-resonance beam is connected with the iron frame to form a relatively concentrated local modal structure with suitable mass distribution and anti-bending and anti-torsion capabilities, and the vibration mode of the modal structure is first-order bending, and the natural frequency is tuned to be close to the compressor rotation frequency. The present invention can effectively suppress the transmission of low-frequency line spectrum vibration of the chiller compressor without significantly increasing the weight of the system, introducing external energy, and reducing the stability and safety of the system.

Description

Technical Field

[0001] The invention relates to the technical field of vibration reduction and noise reduction of a ship chiller, in particular to a vibration reduction common base of a ship chiller. Background Art

[0002] The chiller is an important mechanical equipment in refrigeration engineering. Its main function is to convert the refrigerant in the cold storage into liquid through the compressor and transport it to the condenser pipe side, absorb the heat of the cooling water in the condenser shell side, and finally return it to the cold storage in the form of gasification. The chiller generally adopts an integrated structure, with the condenser, control box, refrigerant water pump, etc. installed on a common base, and the compressor installed above the condenser. In some places with special requirements for vibration reduction and noise reduction, such as ship cabins, the common base is responsible for reducing the vibration transmitted from the chiller to the hull installation base. It is often equipped with several vibration isolators at the bottom to form a vibration reduction common base. The vibration reduction common base is used in many ship electromechanical equipment. In the chiller, it is mainly used to attenuate the vibration generated by the operation of the refrigerant compressor. The vibration is transmitted from the compressor feet, inlet and outlet pipes, etc., and is transmitted to the vibration reduction common base through the condenser shell and feet, and finally transmitted to the hull installation base. This vibration-damping common base belongs to the technical category of vibration isolation in vibration engineering. The effective frequency range of its vibration control is related to the natural frequency of the vibration isolation system composed of the entire device. For example, for a chiller with a vertical first-order natural frequency of 30Hz and a vibration-damping common base, the frequency at which the vibration isolation effect begins to occur is at least 45Hz, which is called the "working area"; there are even risks of resonance and amplified vibration in the frequency range below 45Hz, which is called the "resonance area". The compressor is the main factor in the vibration problem of the chiller, and the low-frequency line spectrum and medium-high frequency large-range vibration are the main factors in the vibration characteristics of the compressor. The medium-high frequency large-range vibration can be well solved by the existing vibration-damping common base, but the low-frequency line spectrum dominated by the compressor speed is not easy to solve. The reason is that the compressor speed is generally in the low-frequency band of 25Hz to 100Hz, which is often in the resonance area or the front of the working area of ​​the chiller vibration isolation system, and it is almost impossible to be effectively suppressed. There are several strategies for the existing low-frequency line spectrum control of chillers:

[0003] 1) Use extremely low frequency vibration isolators, such as air springs. This approach can increase the distance between the system's natural frequency and the compressor's rotation frequency, improving the vibration isolation effect. Although this method improves the vibration isolation problem to a certain extent, it often brings new problems, such as increased vibration intensity of the whole machine, poor swing stability, poor impact safety, etc., which poses a safety hazard in the ship's navigation environment.

[0004] 2) Use a dynamic vibration absorber. A dynamic vibration absorber is a very effective means for low-frequency line spectrum vibration. It generally adopts a first-order spring oscillator structure and is installed on the compressor foot or the vibration reduction common base foot. Although this method is highly targeted, it requires the spring oscillator to have a relatively large weight. In actual design, it is difficult to obtain sufficient weight indicators, which restricts the application effect.

[0005] 3) Use an active vibration control device. An active vibration control device is a control device driven by external energy. Its essence is to introduce a new power source to counteract the original vibration source, and to suppress the vibration of the specified frequency under the condition that the frequency, phase and other parameters are properly adjusted. Due to the introduction of external energy, this technology has obvious disadvantages. The overall weight increases significantly (including power amplifiers, DC power supplies and other components), the reliability decreases significantly, and the energy supply link itself introduces new vibrations. Summary of the invention

[0006] In order to overcome the technical problems of existing line spectrum control means such as heavy weight, high energy consumption or poor stability, the present invention provides a ship chiller vibration reduction common base, which can effectively suppress the transmission of low-frequency line spectrum vibration of the chiller compressor without significantly increasing the system weight, introducing external energy, or reducing the stability and safety of the system.

[0007] To achieve the above-mentioned purpose, the technical solution of the present invention is: a common base for vibration reduction of a ship chiller, which is composed of an iron frame, an anti-resonance beam, a damping filler, a condenser foot mounting plate, and a vibration isolator. The iron frame is the main structure of the common base for vibration reduction, which is used to carry and install all components. The iron frame leaves a space in the form of a well directly below the condenser for the installation of the anti-resonance beam; the anti-resonance beam is a group of detachable or semi-detachable component beams, whose length direction is consistent with the axial direction of the condenser, and whose two ends are fixed on the two end walls of the well of the iron frame; the anti-resonance beam is connected to the iron frame to form a local relatively concentrated modal structure with suitable mass distribution and bending and torsion resistance. The vibration mode of the modal structure is first-order bending, and the natural frequency is tuned to be close to the compressor rotation frequency.

[0008] Furthermore, the damping filler is filled between the compressor feet and the iron frame to improve the ability of medium and high frequency attenuation, while strengthening the low-frequency line spectrum vibration control effect of the entire frame.

[0009] Furthermore, the damping filler is a non-metallic material with elasticity and damping.

[0010] Furthermore, the condenser foot mounting plate is suspended and vulcanized in the damping filler, does not contact any part of the iron frame, and is connected and fixed to the condenser foot through a threaded inner hole with a boss.

[0011] Furthermore, the vibration isolator is installed below the vibration-damping common base, and plays an elastic supporting role for the entire base and the chiller.

[0012] Furthermore, the anti-resonance beam is in the form of an upper and lower layer of spring steel plate beams with an intermediate mass block. The lower layer of spring steel plate beam is welded to the bottom plate of the iron frame or is directly cut to leave a plate beam shape when the bottom plate of the iron frame is cut. The upper layer of spring steel plate beam is connected to the suspension platform plane of the iron frame by bolts. The middle part of the upper layer of spring steel plate beam and the lower layer of spring steel plate beam is clamped and installed with a mass block by through bolts to form a first-order bending local mode.

[0013] Furthermore, weight plates are added or removed from the mass block to fine-tune the natural frequency of the first-order bending local mode.

[0014] Furthermore, the anti-resonance beam adopts a box beam structure and is welded to the iron frame as a whole. The thickness, mass density and arrangement density of the steel plates used gradually increase from both ends to the center, forming a first-order bending local mode.

[0015] Furthermore, the natural frequency of the first-order bending local mode is fine-tuned by adding or removing counterweights on the box beam wall panels of the anti-resonance beam.

[0016] The present invention has the following beneficial effects:

[0017] (1) There is almost no excessive structural mass introduced for the vibration-damping common base, because the anti-resonance beam, which plays a key role in controlling the low-frequency line spectrum, is itself a necessary component to ensure the structural strength;

[0018] (2) The problem is solved completely in a passive way, without the need for external energy or complex sensor control systems, and with high reliability;

[0019] (3) There is no need to deliberately reduce the support frequency of the vibration isolator for low-frequency line spectrum vibration, which improves the stability and safety of the chiller in environments such as ship navigation and combat;

[0020] (4) The combined use of damping fillers and anti-resonance beams has the effect of enhancing the low-frequency line spectrum control effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is an axonometric schematic diagram of the vibration reduction common base structure of the chiller of the present invention;

[0022] Figure 2 It is a schematic cross-sectional view of the vibration-damping common base structure of the chiller of the present invention;

[0023] Figure 3 It is a schematic diagram of the control effect of the low-frequency line spectrum characteristics of the present invention;

[0024] Where: (a) amplitude-frequency, (b) phase-frequency. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0026] like Figure 1 As shown in FIG. 2 , a vibration reduction common base for a ship chiller of the present invention is composed of an iron frame 1, an anti-resonance beam 2, a damping filler 3, a condenser foot mounting plate 4, a vibration isolator 5 and other components. The iron frame 1 is the main structure of the vibration reduction common base, which plays the role of bearing and installing all components. The iron frame 1 leaves a space in the form of a well directly below the condenser for the installation of the anti-resonance beam 2. The anti-resonance beam 2 is a set of detachable or semi-detachable component beams, whose length direction is consistent with the axial direction of the condenser, and whose two ends are fixed on the two end walls of the well of the iron frame 1. The component beam is not only an important component to ensure the strength of the vibration reduction common base, but also a key part of the low-frequency line spectrum vibration control. The component beam should have a suitable mass distribution and anti-bending and anti-torsion capabilities. While strengthening the longitudinal strength of the iron frame 1, it provides stiffness in the vertical, lateral and torsional directions, thereby constructing a relatively concentrated local mode. The vibration shape of this mode is usually a first-order bending, and the natural frequency is generally tuned to be close to the compressor rotation frequency. The damping filler 3 is used to fill a layer of non-metallic material with elasticity and damping between the compressor foot and the iron frame 1, which improves the ability of medium and high frequency attenuation and strengthens the low-frequency line spectrum vibration control effect of the entire frame. The condenser foot mounting plate 4 is suspended and vulcanized in the damping filler 3, and does not contact any part of the iron frame 1. It is connected and fixed through the threaded inner hole condenser foot with a boss. The vibration isolator 5 is below the vibration reduction common base and plays an elastic supporting role for the entire base and the chiller.

[0027] When the chiller is working, the vibration of the compressor is transmitted to the condenser cylinder through the machine foot, and then transmitted to the condenser machine foot mounting plate 4 through the condenser machine foot. After most of the medium and high frequency vibrations are attenuated by the damping filler 3, it is transmitted to the iron frame 1. When the vertical local modal natural frequency of the anti-resonance beam 2 in the iron frame 1 is close to the compressor rotation frequency, an anti-resonance phenomenon will occur, that is, the compressor rotation frequency vibration seems to fall into a "deep well" when passing through the iron frame 1, resulting in a large attenuation, and then further attenuated by the vibration isolator 5, the line spectrum vibration transmitted to the hull mounting base is very small.

[0028] Example 1:

[0029] like Figure 1As shown in FIG. 2 , the anti-resonance beam 2 is in the form of two layers of spring steel plate beams with an intermediate mass block. The lower plate beam 2a is welded to the bottom plate of the iron frame 1 or is directly cut to leave a plate beam shape when the bottom plate of the iron frame 1 is cut. The upper plate beam 2b is connected to the suspension platform plane of the iron frame 1 by bolts. At least three elbow-shaped ribs are welded below the suspension platform plane. Good contact is ensured between the suspension platform surface and the upper plate beam 2b, and they are fastened with no less than three pairs of bolts. The middle part of the lower plate beam 2a and the upper plate beam 2b is clamped and installed with a mass block 2c by through bolts. The upper and lower mounting surfaces of the mass block 2c should be machined to ensure flatness, and the contact area with the lower plate beam 2a and the upper plate beam 2b should be minimized as much as possible under the premise of ensuring clamping stability.

[0030] The structure of the above-mentioned anti-resonance beam 2 is that the total bending stiffness of the lower plate beam 2a and the upper plate beam 2b and the concentrated mass of the mass block 2c constitute a first-order bending local mode. After the natural frequency of the mode is tuned to be basically consistent with the compressor rotation frequency, the chiller is turned on for online debugging, and the natural frequency of the above-mentioned mode is fine-tuned by adding or removing the counterweight plate 2d on the mass block 2c until the line spectrum vibration on the mass block 2c reaches the maximum, and at the same time the line spectrum vibration of the machine foot of the iron frame 1 reaches the minimum, thereby achieving the control purpose.

[0031] In addition to the modes that can be used for line spectrum control, the anti-resonance beam 2 structure in this example also brings many other relatively concentrated local modal vibration modes, such as the 2c mass block flipping, lateral vibration modes, etc. The natural frequencies corresponding to these vibration modes have been precisely designed and have a sufficient gap with the vertical natural frequency (at least 20% or more than 5Hz). Figure 3 (a) and (b) in the figure.

[0032] The implementation form of Example 1 is suitable for situations where the frequency is low and the weight index is sufficient.

[0033] Example 2:

[0034] The anti-resonance beam 2 adopts a box beam structure and is welded to the iron frame 1 as a whole. The thickness, mass density and arrangement density of the steel plate and the internal partitions gradually increase from both ends to the center, forming a first-order bending local mode. After the natural frequency of the mode is tuned to be basically consistent with the compressor rotation frequency, the chiller is turned on for online debugging. The natural frequency of the above mode is fine-tuned by adding or removing counterweights on the box beam wall until the line spectrum vibration in the center of the anti-resonance beam 2 reaches the maximum. At the same time, the line spectrum vibration of the iron frame 1 machine foot reaches the minimum, thereby achieving the control purpose.

[0035] In addition to the modes that can be used for line spectrum control, the anti-resonance beam 2 structure in this example also brings many other relatively concentrated local modal vibration modes, such as lateral and diagonal torsion vibration modes. The natural frequencies corresponding to these vibration modes are precisely designed and have a sufficient gap with the vertical natural frequency (at least 20% or more than 5Hz). Figure 3 (a) and (b) in the figure.

[0036] The implementation form of Example 2 is suitable for situations where the frequency is high and the weight index is tight.

Claims

1. A vibration-damping common base for a ship chiller, characterized in that: It is composed of an iron frame, an anti-resonance beam, a damping filler, a condenser machine foot mounting plate, and a vibration isolator. The iron frame is the main structure of the vibration-damping common base, which is used to carry and install all components. The iron frame leaves a space in the form of a well directly below the condenser for the installation of the anti-resonance beam; the anti-resonance beam is a group of detachable or semi-detachable component beams, whose length direction is consistent with the axial direction of the condenser, and whose two ends are fixed to the walls of the well at both ends of the iron frame; the condenser machine foot mounting plate is suspended and vulcanized in the damping filler, and does not contact any part of the iron frame, and is connected and fixed to the condenser machine foot through a threaded inner hole with a boss; the vibration isolator is installed below the vibration-damping common base, and the entire base The seat and the chiller play an elastic supporting role; the anti-resonance beam is connected with the iron frame to form a relatively concentrated local modal structure with mass distribution and bending and torsion resistance. The vibration mode of the modal structure is first-order bending, and the natural frequency is tuned to be close to the compressor rotation frequency; the anti-resonance beam adopts the form of an upper and lower layer of spring steel plate beams with an intermediate mass block. The lower spring steel plate beam is welded to the bottom plate of the iron frame or directly cut to leave a plate beam shape when the bottom plate of the iron frame is cut. The upper spring steel plate beam is connected to the suspension platform plane of the iron frame by bolts. The middle part of the upper spring steel plate beam and the lower spring steel plate beam is clamped and installed with a mass block by through bolts to form a first-order bending local mode.

2. The vibration-damping common base for a ship chiller according to claim 1, characterized in that: The damping filler is filled between the compressor feet and the iron frame to improve the ability of medium and high frequency attenuation, and at the same time strengthens the low-frequency line spectrum vibration control effect of the entire frame.

3. The vibration-damping common base for a ship chiller according to claim 2, characterized in that: The damping filler is a non-metallic material with elasticity and damping.

4. The vibration-damping common base for a ship chiller according to claim 1, characterized in that: Adding or removing weight plates on the mass block is used to fine-tune the natural frequency of the first-order bending local mode.

5. The vibration-damping common base for a ship chiller according to claim 1, characterized in that: The anti-resonance beam adopts a box beam structure and is welded to an iron frame as a whole. The thickness, mass density and arrangement density of the steel plates used gradually increase from both ends to the center, forming a first-order bending local mode.

6. The vibration-damping common base for a ship chiller according to claim 5, characterized in that: The natural frequency of the first-order bending local mode is fine-tuned by adding or removing counterweights on the box beam wall plate of the anti-resonance beam.

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