Low-noise exhaust valve structure of scroll compressor

Abstract

The application discloses a low-noise exhaust valve structure of a scroll compressor and belongs to the technical field of scroll compressors. The technical scheme is as follows: the exhaust valve structure comprises an exhaust valve sheet, an exhaust valve seat and an exhaust valve limiter, the exhaust valve seat is provided with a valve seat conical notch, the conical notch is formed by a valve seat top conical notch linear, a valve seat bottom circular line and a conical notch edge line, and a conical transition flow channel gradually expanding along the exhaust direction section is formed. The beneficial effects are as follows: the high-pressure exhaust gas flow is gradually expanded from the bottom to the top of the valve seat through the conical notch, the strong pressure pulsation and vortex noise caused by the sudden expansion of the gas flow during the traditional straight slot exhaust are effectively inhibited, the conical edge line can guide the gas flow to flow along the wall, the gas flow impact during the opening moment of the valve sheet is reduced, the overall sound power level can be reduced by about 4dB, the structure is simple, the reliability is high, and the application is suitable for various fixed-speed and variable-condition scroll compressors.

Description

Technical Field

[0001] This invention belongs to the field of scroll compressor technology, and specifically relates to an exhaust valve structure for scroll compressors, and more particularly to a low-noise exhaust valve structure that reduces exhaust aerodynamic noise by optimizing the geometry of the valve seat exhaust passage. Background Technology

[0002] Scroll compressors are widely used in air conditioning, heat pump, and refrigeration systems due to their simple structure, stable operation, and high efficiency. After the scroll compressor's compression chamber completes intake and compression, the high-pressure gas needs to be discharged through the exhaust port and exhaust valve located on the stationary scroll plate. As a key opening and closing component between the compression chamber and the high-pressure chamber, the exhaust valve's structure directly affects the smoothness of exhaust flow and the compressor's aerodynamic noise level.

[0003] In existing technologies, the exhaust ports on the exhaust valve seats of scroll compressors generally adopt a uniform cross-section circular hole or rectangular straight groove structure. During the exhaust process, once the high-pressure gas in the compression chamber pushes open the exhaust valve plate, it instantly rushes from the smaller cross-section exhaust port into the larger volume high-pressure chamber, forming a violent sudden expansion of airflow. This flow not only generates a strong free shear layer at the edge of the exhaust port, but also induces significant pressure pulsation and radiates broadband aerodynamic noise to the compressor casing. Especially when operating under partial load or variable conditions, the frequent slapping of the valve plate and the superposition of airflow impact make the mid-to-high frequency noise particularly prominent.

[0004] To reduce exhaust noise, existing solutions mostly focus on passive noise reduction methods such as adding silencing chambers, wrapping with sound-absorbing cotton, or using multi-layer valve plates. However, these methods often come at the cost of increased structural complexity, sacrifice of some volumetric efficiency, or increased flow resistance. Therefore, how to achieve low-resistance, low-noise exhaust by optimizing the exhaust port geometry, starting from the airflow channel of the exhaust valve seat, remains a pressing technical problem to be solved in this field. Summary of the Invention

[0005] To address the technical problems existing in the prior art, the present invention aims to overcome the shortcomings of existing technologies where the exhaust port of a scroll compressor exhaust valve seat generates strong pressure pulsations and eddy noise due to sudden expansion of airflow. The invention provides a low-noise exhaust valve structure for a scroll compressor that is simple in structure, easy to manufacture, and highly reliable. This structure designs the exhaust port of the valve seat as a conical transition groove, allowing the high-pressure airflow to expand gradually along the exhaust direction, thereby effectively suppressing airflow noise and valve plate impact noise.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A low-noise exhaust valve structure for a scroll compressor includes an exhaust valve plate, an exhaust valve seat, and an exhaust valve limiter. The exhaust valve seat has a through conical groove, which is formed by the conical groove line at the top of the valve seat, the circular line at the bottom of the valve seat, and the edge line of the conical groove connecting the conical groove line at the top of the valve seat and the circular line at the bottom of the valve seat, forming a conical transition channel with a gradually expanding cross-section along the exhaust direction. The exhaust valve plate is disposed on the upper end face of the exhaust valve seat and opens under exhaust pressure to connect with the conical groove of the valve seat; The exhaust valve limiter is located above the exhaust valve plate and is used to limit the maximum opening height of the exhaust valve plate.

[0007] Furthermore, the top conical groove of the valve seat is a periodic wavy line formed by the smooth connection of at least two alternating arc segments.

[0008] Furthermore, the arc segment is a semicircle, a semicircle-like segment, or a sine curve segment.

[0009] Furthermore, the periodic wave line has 8 to 12 sets of the circular arc segments distributed circumferentially.

[0010] Furthermore, the edge line of the conical groove is a ruled curved surface generatrix that smoothly transitions from the circular line at the bottom of the valve seat to the conical groove at the top of the valve seat.

[0011] Furthermore, the edge line of the conical groove is a slightly convex arc that smoothly transitions from the circular line at the bottom of the valve seat to the conical groove at the top of the valve seat.

[0012] Furthermore, the cone angle of the valve seat conical groove is 5°~30°, and the cone angle is the angle between the edge line of the conical groove and the axis of the exhaust valve seat.

[0013] Furthermore, the exhaust valve seat is also provided with valve seat bolt holes, which are distributed on the outer periphery of the valve seat conical groove, for fastening the exhaust valve seat to the stationary scroll plate of the scroll compressor.

[0014] Furthermore, the exhaust valve plate is a circular thin plate, and the coverage area of ​​the exhaust valve plate is larger than the area enclosed by the conical groove at the top of the valve seat.

[0015] Furthermore, the stiffness of the exhaust valve plate is matched with the limiting height of the exhaust valve limiter, so that when the exhaust valve plate is at its maximum opening height, the edge of the exhaust valve plate is located within the axial projection range of the tapered transition channel of the valve seat tapered groove.

[0016] The beneficial effects of this invention are: Compared with the prior art, the low-noise exhaust valve structure of the scroll compressor described in this invention has the following technical features and beneficial effects: 1. This invention creates a conical transition channel with a gradually expanding cross-section along the exhaust direction by setting a conical groove on the valve seat, which is formed by the conical groove line at the top of the valve seat, the circular line at the bottom of the valve seat, and the edge line of the conical groove. This allows the high-pressure exhaust airflow to achieve gradual pressure release and velocity reduction when flowing through the conical groove. Unlike the sudden expansion of airflow caused by existing uniform cross-section circular holes or rectangular straight groove exhaust ports, this invention uses the constraint effect of the conical wall to transform the single sudden expansion into a quasi-one-dimensional gradual expansion process, effectively suppressing the strong pressure pulsation and eddy noise caused by the roll-up of the free shear layer. The overall sound power level can be reduced by about 4dB. 2. This invention sets the tapered groove at the top of the valve seat as a periodic wavy line smoothly connected by at least two alternating arc segments, so that the exhaust port edge alternately forms multiple convex arc segments and concave arc segments in the circumferential direction. This wavy edge breaks the circumferential periodicity of the shear layer roll-up structure at the edge of the traditional circular hole or straight groove exhaust port, and avoids the formation of highly coherent vortex shedding at a specific frequency of airflow, thereby effectively weakening the noise peak at discrete frequencies, making the exhaust noise spectrum tend to be flat, which is beneficial to improving the sound quality of the compressor. 3. In this invention, the top conical groove of the valve seat is designed as a periodic wavy line, with the curvature centers of adjacent arc segments located on both sides of the wavy line. This causes the airflow to undergo a gradual lateral expansion at the convex arc segments of the wavy line as it flows through the top outlet of the conical groove of the valve seat, while forming a local steady flow zone at the concave arc segments. This multiple small-amplitude expansion replaces the single, violent cross-sectional expansion during traditional straight-groove exhaust, effectively suppressing the large-scale roll-up of the free shear layer. At the same time, it significantly increases the effective perimeter of the exhaust port, promotes momentum exchange between the airflow and the wall, further weakens the intensity of turbulent pulsation, and reduces the radiated energy of mid-to-high frequency turbulent noise. 4. This invention utilizes the inclined wall surface formed by the edge of the conical groove along the exhaust direction to significantly reduce the rate of change of airflow pressure below the valve plate during the opening of the exhaust valve plate, thereby reducing the impact speed and impact force of the valve plate; the stiffness of the exhaust valve plate is matched with the limiting height of the exhaust valve limiter, so that when the valve plate is fully opened, its edge is still located in the conical expansion channel area of ​​the conical groove of the valve seat, avoiding the secondary impact noise caused by the airflow encountering the unconstrained cross section abrupt expansion after the valve plate is opened, thus effectively reducing the structural radiation noise caused by the valve plate impact; 5. This invention achieves significant noise reduction by simply creating a conical groove on the exhaust valve seat and setting a periodic wavy linear outlet, without adding extra parts or silencing components. The machining can be completed by conventional milling or wire cutting, improving acoustic performance without increasing structural complexity or assembly difficulty. This exhaust valve structure can be adapted to constant speed and variable frequency scroll compressors of different displacements, and can maintain a stable noise reduction trend under different speeds and variable operating conditions. Moreover, as the speed increases and the exhaust pulsation frequency increases, the advantage of the conical groove in suppressing high-frequency noise becomes more prominent. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the overall structure assembly of the exhaust valve of the present invention; Figure 2 This is a cross-sectional view of the exhaust valve of the present invention; Figure 3 This is a schematic diagram of the exhaust valve seat structure of the present invention; Figure 4 This is a top view of the exhaust valve seat of the present invention; Figure 5 This is a schematic diagram of the valve seat groove shape of the present invention; Figure 6 Comparison of overall noise power between the original exhaust valve and the conical groove exhaust valve Figure 1 ; Figure 7 Comparison of overall noise power between the original exhaust valve and the conical groove exhaust valve Figure 2 ; Figure 8 A comparison chart of the A-weighted sound pressure levels at 1m in the acoustic field between the original exhaust valve and the conical groove exhaust valve; The attached figures are labeled as follows: 1-exhaust valve plate, 2-exhaust valve seat, 201-conical groove of valve seat, 202-bolt hole of valve seat, 203-line of conical groove at the top of valve seat, 204-circular line at the bottom of valve seat, 205-edge line of conical groove, 3-exhaust valve limiter. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The following description, in conjunction with the accompanying drawings... Figures 1-8 Further explanation of the structure of the low-noise exhaust valve for the scroll compressor.

[0019] Example 1 A low-noise exhaust valve structure for a scroll compressor includes an exhaust valve plate 1, an exhaust valve seat 2, and an exhaust valve limiter 3. The exhaust valve seat 2 has a through-hole conical groove 201, which is formed by a conical groove line 203 at the top of the valve seat, a circular line 204 at the bottom of the valve seat, and a conical groove edge line 205 connecting the two, creating a conical transition channel with a gradually expanding cross-section along the exhaust direction. The exhaust valve plate 1 is located on the upper surface of the exhaust valve seat 2 and opens under exhaust pressure to connect with the conical groove 201. The exhaust valve limiter 3 is positioned above the exhaust valve plate 1 and limits the maximum opening height of the exhaust valve plate 1 to prevent excessive deformation or breakage of the valve plate.

[0020] Preferably, the conical groove line 203 at the top of the valve seat is a periodic wavy line smoothly connected by at least two alternating arc segments. The arc segments are semicircles, near-semicircles, or sinusoidal curves, with the curvature centers of adjacent arc segments located on opposite sides of the wavy line. The circular line 204 at the bottom of the valve seat is a circular line. The edge line 205 of the conical groove is a ruled surface generatrix or a slightly convex arc that smoothly transitions from the circular line 204 at the bottom of the valve seat to the conical groove line 203 at the top of the valve seat.

[0021] Preferably, the cone angle of the valve seat conical groove 201, that is, the angle between the edge line 205 of the conical groove and the axis of the exhaust valve seat 2, is 5°~30°. This angle range takes into account both noise reduction effect and structural strength: if the cone angle is too small, the expansion stroke will be too long and the axial dimension of the valve seat will increase; if the cone angle is too large, the airflow expansion will be too rapid and the noise reduction effect will be weakened.

[0022] Preferably, the exhaust valve seat 2 is further provided with valve seat bolt holes 202, which are distributed on the outer periphery of the valve seat conical groove 201, and are used to fasten the exhaust valve seat 2 to the stationary scroll plate of the scroll compressor.

[0023] Preferably, the exhaust valve plate 1 is a circular thin plate that completely covers the area enclosed by the conical groove line 203 at the top of the valve seat, and the rigidity of the exhaust valve plate 1 matches the limiting height of the exhaust valve limiter 3, so that the exhaust valve plate 1 is still located in the conical expansion channel area of ​​the conical groove 201 of the valve seat when it is fully open, thus avoiding the airflow from encountering the expansion section again after the valve plate is opened.

[0024] The working principle of this invention is as follows: When the pressure inside the scroll compressor's compression chamber reaches the discharge pressure, the high-pressure gas acts on the lower surface of the discharge valve plate 1 and pushes it open. At this time, the airflow starts from the circular cross-section defined by the circular line 204 at the bottom of the valve seat and flows upward along the edge line 205 of the conical groove. Since the shape 203 of the conical groove at the top of the valve seat is a periodic wavy line, the gas in the compression chamber does not directly enter a large volume space with a uniform cross-section, but first flows through the conical groove 201 of the valve seat. As the cross-section of the conical groove gradually expands along the discharge direction, the airflow achieves gradual pressure release and velocity reduction under the constraint of the conical wall, effectively avoiding the free expansion flow in traditional straight groove discharge.

[0025] Furthermore, since the conical groove at the top of the valve seat has a periodic wavy shape (203), the exhaust port consists of multiple small-scale expansion zones distributed alternately along the circumference: the airflow exhibits gradual lateral expansion at the convex arc segments of the wavy line, while forming local steady flow zones at the concave arc segments. This multiple small-amplitude expansion effectively suppresses the large-scale roll-up of the free shear layer, while the wavy edge disrupts the circumferential periodicity of the shear layer roll-up structure, reducing the noise peak at discrete frequencies. In addition, the wavy shape significantly increases the effective perimeter of the exhaust port, promoting momentum exchange between the airflow and the wall, further weakening the intensity of turbulent fluctuations.

[0026] Compared with the prior art, the present invention has the following significant advantages: 1. Significant noise reduction effect: Alternating semicircles or sinusoidal wavy lines transform the sudden expansion of airflow into multiple gradual expansions, which can reduce the sound power level by about 4dB overall; 2. Suppressing discrete peaks: The wavy edge disrupts the circumferential periodicity of the shear layer roll-up structure, avoiding the discrete noise peaks generated at specific frequencies by traditional circular hole exhaust ports; 3. Simple and reliable structure: Only the local geometry of the valve seat exhaust port is changed, without adding any extra parts, and the machining can be completed by conventional milling or wire cutting; 4. Wide applicability: This valve seat structure can be adapted to scroll compressors of different displacements, and has stable noise reduction performance for both constant speed and variable operating conditions.

[0027] Example 2 like Figure 1 and Figure 2As shown, the present invention provides a low-noise exhaust valve structure for a scroll compressor, mainly comprising an exhaust valve plate 1, an exhaust valve seat 2, and an exhaust valve limiter 3. The exhaust valve seat 2 is fastened to the exhaust end face of the stationary scroll plate of the scroll compressor through valve seat bolt holes 202 opened on its outer periphery. The exhaust valve plate 1 is placed on the upper end face of the exhaust valve seat 2, and the exhaust valve limiter 3 is fixed above the exhaust valve seat 2 by bolt connection. A gap is maintained between the two to allow the exhaust valve plate 1 to open upwards. The height of this gap is the maximum opening height of the exhaust valve plate 1, which is usually designed according to the compressor displacement.

[0028] like Figure 3 and Figure 5 As shown, the core improvement of this invention lies in the conical groove 201 and its top profile on the exhaust valve seat 2. The top conical groove profile 203 is a periodic wavy line, smoothly connected by multiple alternating convex and concave arcs. In a preferred embodiment, the convex and concave arcs are arcs with a diameter of 4mm, evenly distributed in 12 groups along the circumference, forming a petal-shaped exhaust port profile with 12 peaks and 12 troughs. In another embodiment, the convex and concave arcs can also be arcs with a central angle of 120° or sine curve segments to adapt to different exhaust volumes and installation space requirements.

[0029] The included angle between the edge line 205 of the conical groove and the axis of the exhaust valve seat 2 is preferably 5° to 30°. When the included angle is 5° to 10°, the axial height of the conical groove 201 is relatively small, which is suitable for compact compressors with limited axial installation space; when the included angle is 10° to 30°, the expansion stroke is longer and the noise reduction effect is better, which is suitable for air conditioning and heat pump systems with high noise requirements. The selection of this included angle also needs to take into account the feasibility of processing: if the included angle is too small, the difference between the bottom circle and the top line will be too small, and the processing positioning accuracy requirement will be high; if the included angle is too large, it will be close to a straight groove, and the noise reduction effect will be weakened.

[0030] The exhaust valve plate 1 is made of a thin, circular stainless steel sheet with a thickness of 0.2~0.4mm. Its planar projected area completely covers the area enclosed by the conical groove 203 at the top of the valve seat, ensuring that the gas in the high-pressure chamber will not flow back into the compression chamber when the compressor stops or during intake. The rigidity of the exhaust valve plate 1 and the limiting height of the exhaust valve limiter 3 must be designed to match: under the maximum exhaust pressure, the opening height of the valve plate 1 should be limited to the conical expansion area of ​​the conical groove 201 of the valve seat. That is, after the valve plate 1 opens, the airflow can still flow under the constraint of the conical wall, and will not immediately enter the unconstrained large-volume high-pressure chamber to form a secondary expansion.

[0031] The noise reduction mechanism of this invention can be further explained by combining fluid mechanics and acoustic principles. In a traditional straight-groove exhaust valve, high-pressure gas flows from a cross-sectional area of... A 0The static vortex exhaust port suddenly surged into the cross-sectional area greater than A 0 The exhaust valve cavity surface, according to the local loss theory, has a local resistance coefficient. ζ ≈(1- A 0 / A 1) 2 This is accompanied by strong turbulent fluctuations and broadband noise. However, in the conical slot 201 of this invention, the airflow undergoes a quasi-one-dimensional gradual expansion process under the constraint of the conical wall, with the cross-sectional area increasing from... A 0 Gradually increase along the axial direction to A 1 Due to the guiding effect of the conical wall, large-scale separation of the airflow boundary layer is less likely to occur, and the large-scale coherent structures generated in the shear layer are effectively broken up, suppressing their pulsation intensity and thus reducing mid-to-high frequency turbulence noise. In addition, the gradual expansion significantly reduces the pressure change rate below valve plate 1, lowering the tapping speed and force of valve plate 1, thereby correspondingly reducing the structural radiation noise.

[0032] Figure 6 and Figure 7 A comparison of the acoustic power level contour maps of the exhaust flow field of the prototype straight-mouth exhaust valve and the modified conical toothed exhaust valve is presented. The figures show that the prototype exhaust valve forms a strong free shear layer and vortex shedding at the exhaust port edge, resulting in a high acoustic power level in the vortex region, with a local peak reaching 61 dB. The noise source is relatively concentrated and spatially distributed. However, after adopting the conical toothed structure of this invention, the vortex intensity near the exhaust port is significantly weakened, the acoustic power level contour map shifts to a lower energy level overall, the peak acoustic power level drops to around 57 dB, and the area of ​​the high-noise region is significantly reduced. The results indicate that the conical toothed structure effectively disrupts the spatial periodicity of the exhaust port edge, significantly reducing the acoustic radiation energy of the exhaust flow field.

[0033] Figure 8 A bar chart comparing the A-weighted sound pressure level (SPL) at 1 m in the 1 / 3 octave band between the conical toothed exhaust valve of this invention and the prototype straight-mouth exhaust valve under the same operating conditions is presented. The horizontal axis represents the center frequency of the 1 / 3 octave band, and the vertical axis represents the A-weighted SPL. The chart shows that the prototype straight-mouth exhaust valve exhibits a significant SPL peak near 500 Hz, with a relatively high overall SPL in the low-to-mid-frequency range of 400–630 Hz. However, with the conical toothed structure of this invention, this peak is significantly reduced, and the SPL is noticeably lower throughout the entire test frequency band. The overall noise reduction effect is significant, demonstrating that the conical toothed structure of this invention has a significant suppression effect on broadband exhaust noise.

[0034] In another embodiment with varying operating conditions, the exhaust valve structure of the present invention is applied to a variable frequency scroll compressor. At different speeds, the conical slot exhaust valve maintains a stable noise reduction trend, and as the speed increases and the exhaust pulsation frequency increases, the advantage of the conical slot in suppressing high-frequency noise becomes more prominent. The present invention is not only applicable to constant-speed compressors but also meets the current requirements of variable frequency scroll compressors for low-noise operation under wide operating conditions.

[0035] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art, within the technical scope disclosed in the present invention, may make equivalent substitutions or modifications based on the technical solution and inventive concept of the present invention, such as changing the conical groove edge 205 to an inwardly concave arc to adapt to a specific airflow direction, or changing the valve seat top line 203 to other types of curves, all of which should be covered within the scope of protection of the present invention.

[0036] Example 3 The specific embodiments of the low-noise exhaust valve structure for a scroll compressor provided by the present invention will be further described in detail below with reference to the accompanying drawings. This embodiment aims to fully disclose the technical solution of the present invention, enabling those skilled in the art to understand and implement the present invention.

[0037] Please see Figure 1 and Figure 2 This invention provides a low-noise exhaust valve structure for a scroll compressor, mainly comprising an exhaust valve plate 1, an exhaust valve seat 2, and an exhaust valve limiter 3. The exhaust valve seat 2 has a disc-shaped structure with a conical groove 201 extending through its upper and lower end faces in its central region. This conical groove 201 guides the compressed high-pressure gas from the compression chamber of the scroll compressor to the high-pressure chamber. The exhaust valve seat 2 is installed on the exhaust end face of the stationary scroll of the scroll compressor via bolt holes 202 on its outer periphery and secured with bolts, ensuring that the conical groove 201 aligns and communicates with the exhaust port on the stationary scroll. The exhaust valve plate 1 is placed on the upper end face of the exhaust valve seat 2, covering the top outlet of the conical groove 201. The exhaust valve plate 1 can open upwards under the pushing action of the high-pressure gas in the compression chamber. The exhaust valve limiter 3 is fixed above the exhaust valve seat 2 by bolt connection. A gap is maintained between the two to allow the exhaust valve plate 1 to open upward. The height of this gap is the maximum opening height of the exhaust valve plate 1. This maximum opening height is usually determined according to the compressor displacement design.

[0038] Please see Figures 3 to 5The core improvement of this invention lies in the geometric configuration of the valve seat conical groove 201 opened on the exhaust valve seat 2. The valve seat conical groove 201 is formed by a valve seat top conical groove line 203, a valve seat bottom circular line 204, and a conical groove edge line 205 connecting the valve seat top conical groove line 203 and the valve seat bottom circular line 204. The valve seat bottom circular line 204 is a circular line located on the lower end face of the exhaust valve seat 2, i.e., the air inlet end, and is connected to the exhaust port of the stationary vortex disk. The valve seat top conical groove line 203 is a periodic wavy line located on the upper end face of the exhaust valve seat 2, i.e., the air outlet end, and is smoothly connected by multiple alternating convex and concave arc segments. The curvature centers of adjacent arc segments are located on both sides of the wavy line, thus forming an exhaust port profile resembling a petal or tooth shape.

[0039] In one specific embodiment, each arc segment is a semi-circular arc segment with a diameter of 4mm, and 12 sets are evenly distributed circumferentially to form a periodic wavy linear outlet profile with 12 crests and 12 troughs. In another embodiment, each arc segment may also be an arc segment with a central angle of 120° or a sine curve segment to adapt to different exhaust volume and installation space requirements. The conical groove edge line 205 is a ruled curved generatrix that smoothly transitions from the circular line 204 at the bottom of the valve seat to the conical groove line 203 at the top of the valve seat; in another embodiment, the conical groove edge line 205 may also be a slightly convex arc. The valve seat conical groove 201 formed by the above three lines forms a conical transition channel with a gradually increasing cross-sectional area along the exhaust direction (i.e., from bottom to top). In other words, the air inlet (lower end) of the valve seat conical groove 201 has a circular cross section, the air outlet (upper end) has a periodic wavy cross section, and the two ends are smoothly connected through the edge line 205 of the conical groove in the middle. The entire channel is gradually expanding in the direction of airflow.

[0040] Furthermore, a certain angle is formed between the edge line 205 of the conical groove and the vertical axis of the exhaust valve seat 2. This angle is the cone angle of the conical groove 201 of the valve seat. The cone angle ranges from 5° to 30°. When the cone angle is in the range of 5° to 10°, the axial height of the conical groove 201 of the valve seat is relatively small, which helps to save axial installation space and is suitable for compact scroll compressors. When the cone angle is in the range of 10° to 30°, the expansion stroke of the conical transition channel is longer, the gradual expansion process of the airflow under the constraint of the conical wall is more complete, and the noise reduction effect is more significant, which is suitable for air conditioning and heat pump systems with high noise requirements. The selection of this cone angle needs to take into account both processing feasibility and noise reduction effect: if the cone angle is too small, the difference in cross-sectional dimensions between the bottom circular line 204 of the valve seat and the top conical groove line 203 of the valve seat will be too small, requiring high processing positioning accuracy; if the cone angle is too large, the conical transition channel will approach a straight groove structure, the airflow expansion will be rapid, and the noise reduction effect will be weakened accordingly. In addition, the periodic wavy line structure of the tapered groove line 203 on the top of the valve seat significantly increases the effective circumference of the exhaust port, allowing the airflow to obtain a larger flow area and a richer wall guiding effect when passing through the exhaust end.

[0041] Please continue reading. Figure 1 and Figure 2 The exhaust valve plate 1 is a circular thin sheet structure made of stainless steel with a thickness ranging from 0.2mm to 0.4mm. The planar projected area of ​​the exhaust valve plate 1 completely covers the area enclosed by the conical groove line 203 at the top of the valve seat. That is, when the exhaust valve plate 1 is closed, its edge extends beyond the circumcircle of the conical groove line 203 at the top of the valve seat. This ensures that when the compressor stops or is in the suction phase, the gas in the high-pressure chamber will not flow back into the compression chamber through the contact surface between the exhaust valve plate 1 and the exhaust valve seat 2. The exhaust valve plate 1 has a predetermined elastic stiffness. The exhaust valve limiter 3 is positioned above the exhaust valve plate 1 and has a predetermined limiting height (i.e., the clearance height for the exhaust valve plate 1 to open upwards). The stiffness of the exhaust valve plate 1 and the limiting height of the exhaust valve limiter 3 are designed to match each other. Specifically, when the exhaust valve plate 1 is lifted to its maximum opening height under maximum exhaust pressure, the edge portion of the exhaust valve plate 1 should still be within the axial projection range of the conical expansion channel area of ​​the conical groove 201 of the valve seat. In other words, after the exhaust valve plate 1 is opened, the airflow discharged from the conical groove 201 of the valve seat is still constrained and guided by the conical wall, and will not immediately enter the unconstrained large-volume high-pressure chamber space at the edge of the valve plate to form a secondary expansion. This matching design ensures that the present invention can achieve a progressive expansion noise reduction effect throughout the entire stroke of the valve plate opening.

[0042] The working principle and exhaust flow process of this invention are described in detail below.

[0043] As the gas in the compression chamber of the scroll compressor is compressed, its pressure gradually increases. When the pressure in the compression chamber reaches the discharge pressure threshold, the high-pressure gas enters the bottom inlet of the valve seat conical groove 201 (i.e., the circular cross-section defined by the bottom circular line 204 of the valve seat) from the discharge port of the stationary scroll plate. The high-pressure gas acts on the lower surface of the discharge valve plate 1, overcoming the elastic restoring force of the discharge valve plate 1 and the back pressure in the high-pressure chamber, pushing the discharge valve plate 1 upward. With the opening of the discharge valve plate 1, the top outlet of the valve seat conical groove 201 connects with the high-pressure chamber, and the high-pressure gas in the compression chamber begins to be discharged.

[0044] As the airflow passes through the conical groove 201 of the valve seat, it first enters through the circular cross-section defined by the circular line 204 at the bottom of the valve seat, and then flows upward along the conical wall defined by the edge line 205 of the conical groove. Because the cross-sectional area of ​​the conical groove 201 gradually increases along the exhaust direction, the airflow undergoes a quasi-one-dimensional gradual expansion process under the constraint of the conical wall, with the cross-sectional area gradually increasing axially from a circular cross-section at the bottom to a periodic wavy cross-section at the top. During this process, the pressure of the high-pressure gas is gradually released, and the flow velocity gradually decreases, avoiding the sudden expansion phenomenon caused by the instantaneous influx of airflow from a smaller cross-section into a larger volume space, as seen in traditional uniform cross-section circular or rectangular straight groove exhaust ports.

[0045] As the airflow continues to rise and approaches the top outlet of the valve seat conical slot 201, the airflow outlet section is composed of alternating convex and concave arc segments due to the periodic wavy shape of the top conical slot 203. At this wavy outlet, the airflow further exhibits the following flow effects: at the convex arc segments, the airflow undergoes gradual lateral expansion, with the airflow streamlines smoothly unfolding along the convex wall; while at the concave arc segments, the airflow velocity is relatively reduced, forming a local steady flow region. The entire wavy outlet decomposes the traditional single sudden expansion into multiple small-scale expansion zones distributed alternately along the circumference. This multiple small-amplitude expansion effectively suppresses the large-scale roll-up of the free shear layer, while the wavy edge disrupts the circumferential periodicity of the free shear layer roll-up structure, avoiding the coherent superposition of vortex shear structures at specific frequencies, thereby reducing the noise peak at discrete frequencies. Furthermore, the wavy edge significantly increases the effective perimeter of the exhaust port, enhancing the momentum exchange between the airflow and the wall, further weakening the intensity of turbulent fluctuations, thus reducing the radiated energy of mid-to-high frequency turbulent noise.

[0046] During the opening and closing of the exhaust valve plate 1, the rate of change of airflow pressure below the exhaust valve plate 1 is significantly reduced compared to a traditional straight groove exhaust port because the conical wall of the valve seat conical groove 201 provides a gradually expanding airflow channel. This results in a smoother opening process for the exhaust valve plate 1, and a reduction in the speed and force at which the valve plate 1 strikes the exhaust valve limiter 3 upwards, thereby reducing the structural radiation noise.

[0047] When the exhaust process in the compression chamber ends and the pressure in the compression chamber drops below the pressure in the high-pressure chamber, the exhaust valve plate 1 falls back down under its own elastic restoring force and the back pressure of the high-pressure chamber, and re-attaches to the upper end face of the exhaust valve seat 2, sealing the top outlet of the valve seat conical groove 201, thus completing a complete exhaust cycle.

[0048] Please see Figure 6 and Figure 7 This paper presents a comparison of the sound power level contour maps of the exhaust flow field under the same exhaust conditions between a prototype straight-mouth exhaust valve (i.e., an existing exhaust valve structure using a circular exhaust port with a uniform cross-section) and an exhaust valve using the conical groove structure of this invention. The figures show that the prototype straight-mouth exhaust valve forms a strong free shear layer and vortex shedding structure at the exhaust port edge, resulting in a high sound power level in the vortex region, with a local peak reaching 61 dB. The noise source is concentrated at the exhaust port edge and exhibits a clear spatial distribution. In contrast, with the conical groove structure of this invention, the vortex intensity near the exhaust port is significantly weakened, the sound power level contour map shifts to a lower energy level overall, the peak sound power level drops to around 57 dB, and the area of ​​the high-noise region is significantly reduced. These comparative results demonstrate that this invention effectively disrupts the spatial periodicity of the exhaust port edge through the conical groove structure, significantly reducing the acoustic radiation energy of the exhaust flow field.

[0049] Please see Figure 8 , Figure 8 A bar chart comparing the A-weighted sound pressure level (SPL) of the conical slotted exhaust valve of this invention and the prototype straight-mouth exhaust valve at a distance of 1m from the exhaust valve under the same operating conditions is provided. The horizontal axis represents the center frequency of the 1 / 3 octave band, and the vertical axis represents the A-weighted SPL. The chart clearly shows that the prototype straight-mouth exhaust valve exhibits a significant SPL peak near the 500Hz center frequency, with a relatively high overall SPL in the low-to-mid frequency range of 400Hz to 630Hz. However, with the conical slotted structure of this invention, this prominent peak is significantly weakened, and the SPL is significantly reduced throughout the entire test frequency band, demonstrating a significant overall noise reduction effect across the entire frequency range. The above experimental data fully demonstrate that the conical slotted structure of this invention has a significant suppression effect on broadband exhaust noise.

[0050] In another embodiment with varying operating conditions, the exhaust valve structure of the present invention is applied to a variable frequency scroll compressor. Under different speed conditions, the conical transition channel of the valve seat conical groove 201 can exert a progressive expansion noise reduction effect, and as the speed increases and the exhaust pulsation frequency increases accordingly, the advantage of the conical groove in suppressing high-frequency noise becomes more prominent. This indicates that the present invention is not only applicable to constant speed compressors, but also meets the current requirements of variable frequency scroll compressors for wide-range, low-noise operation.

[0051] The valve seat conical groove 201 of the exhaust valve seat 2 of the present invention can be formed by conventional milling or wire cutting, without the need to add additional noise reduction components or sound absorption materials, without changing the overall assembly process of the compressor, and has good process inheritance and economy.

[0052] This invention designs the exhaust passage of the exhaust valve seat 2 as a conical transition channel structure formed by the conical groove line 203 at the top of the valve seat, the circular line 204 at the bottom of the valve seat, and the edge line 205 of the conical groove. This allows the high-pressure exhaust airflow to gradually expand during the discharge process, effectively suppressing pressure pulsation and eddy noise, and significantly reducing the sound radiation energy of the exhaust valve. At the same time, the structure is simple and reliable, easy to process, and suitable for various constant speed and variable frequency scroll compressors.

[0053] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A low-noise exhaust valve structure for a scroll compressor, comprising an exhaust valve plate (1), an exhaust valve seat (2), and an exhaust valve limiter (3), characterized in that: The exhaust valve seat (2) is provided with a through valve seat conical groove (201). The valve seat conical groove (201) is formed by the valve seat top conical groove line (203), the valve seat bottom circular line (204), and the conical groove edge line (205) connecting the valve seat top conical groove line (203) and the valve seat bottom circular line (204), forming a conical transition channel with a gradually expanding cross section along the exhaust direction. The exhaust valve plate (1) is disposed on the upper end face of the exhaust valve seat (2) and opens under exhaust pressure to connect the conical groove (201) of the valve seat. The exhaust valve limiter (3) is located above the exhaust valve plate (1) and is used to limit the maximum opening height of the exhaust valve plate (1).

2. The low-noise exhaust valve structure for a scroll compressor according to claim 1, characterized in that: The tapered groove (203) at the top of the valve seat is a periodic wavy line formed by the smooth connection of at least two alternating arc segments.

3. The low-noise exhaust valve structure for a scroll compressor according to claim 2, characterized in that: The arc segment is a semicircle, a semicircle-like segment, or a sine curve segment.

4. The low-noise exhaust valve structure of the scroll compressor according to claim 2, characterized in that: The periodic wavy line has 8 to 12 sets of circular arc segments distributed circumferentially.

5. The low-noise exhaust valve structure for a scroll compressor according to claim 1, characterized in that: The conical groove edge line (205) is a ruled surface generatrix that smoothly transitions from the circular line (204) at the bottom of the valve seat to the conical groove line (203) at the top of the valve seat.

6. The low-noise exhaust valve structure of the scroll compressor according to claim 1, characterized in that: The edge line (205) of the conical groove is a slightly convex arc that smoothly transitions from the circular line (204) at the bottom of the valve seat to the conical groove line (203) at the top of the valve seat.

7. The low-noise exhaust valve structure for a scroll compressor according to claim 1, characterized in that: The cone angle of the valve seat conical groove (201) is 5°~30°, and the cone angle is the angle between the edge line (205) of the conical groove and the axis of the exhaust valve seat (2).

8. The low-noise exhaust valve structure of the scroll compressor according to claim 1, characterized in that: The exhaust valve seat (2) is also provided with valve seat bolt holes (202), which are distributed on the outer periphery of the valve seat conical groove (201) and are used to fasten the exhaust valve seat (2) to the stationary scroll plate of the scroll compressor.

9. The low-noise exhaust valve structure for a scroll compressor according to claim 1, characterized in that: The exhaust valve plate (1) is a circular thin plate, and the coverage area of ​​the exhaust valve plate (1) is larger than the area enclosed by the conical groove line (203) at the top of the valve seat.

10. The low-noise exhaust valve structure of the scroll compressor according to claim 1, characterized in that: The stiffness of the exhaust valve plate (1) matches the limiting height of the exhaust valve limiter (3), so that when the exhaust valve plate (1) is at its maximum opening height, the edge of the exhaust valve plate (1) is within the axial projection range of the tapered transition channel of the valve seat tapered groove (201).

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