Flow Control Valve

Abstract

To provide a flow rate adjustment valve capable of effectively reducing noise generated due to pressure fluctuation and a refrigerant separation phenomenon in passing through a valve port, and reducing pressure loss and the like.SOLUTION: In a flow rate adjustment valve 1 including a valve main body 5 provided with: a valve chest 6 and a valve port 10; and a valve body 30 designed to obtain an equal percent characteristic or a characteristic approximate thereto as flow rate characteristics and having a curved surface portion 33 for changing a flow rate of fluid flowing through the valve port 10 according to a lifting amount, and increased in curvature or control angle of the curved surface portion 33 continuously or gradually toward a tip, a diameter of the valve port 10 is successively increased in three or more stages in accordance with separation from the valve chest 6. Concretely, a first valve port portion 11 having a diameter D1, a second valve port portion 12 having a diameter D2 (>D1), and a third valve port portion 13 having a diameter D3(>D2) are successively disposed from the valve chest 6 side. More preferably, D1, D2, D3 are determined so that (valve port ratio: D2 / D1) and (valve port ratio: D3 / D2) are kept within prescribed ranges.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a flow control valve including a valve body provided with a valve chamber and a valve port (orifice), and a valve element that changes the flow rate of fluid flowing through the valve port in accordance with a lift amount, and in particular to a flow control valve suitable for adjusting the refrigerant flow rate in a heat pump type heating and cooling system or the like. [Background technology]

[0002] Well-known flow control valves have a relationship between valve opening (lift amount) and flow rate, that is, flow rate characteristics, which are linear characteristics and equal percentage characteristics. Linear characteristics are characteristics in which the rate of change of flow rate relative to changes in valve opening is constant, while equal percentage characteristics are characteristics in which the rate of change of valve opening is proportional to the flow rate.

[0003] Fig. 5 shows the main part of an example of a flow control valve that is adapted to obtain equal percentage characteristics. The illustrated flow control valve 1' is used to adjust the refrigerant flow rate in a heat pump type air conditioning system or the like, and includes a valve body 5 having a valve chamber 6, a valve seat 8 formed of an inverted truncated cone surface, and a valve port 15 formed of a cylindrical surface, and a valve body 20 that changes the flow rate of the fluid that flows through the valve port 15 according to the lift amount from the valve seat 8. The valve body 20 is raised and lowered so as to approach and separate from the valve seat 8 by a screw feed type lifting drive mechanism that is composed of a valve stem with a male thread, a guide stem with a female thread, and a stepping motor, as described in Patent Document 1, for example.

[0004] The valve body 20 has a contact surface portion 22 that contacts the valve seat 8, and an elliptical curved surface portion 23 that is connected to the lower side of the contact surface portion 22 and is intended to obtain equal percentage characteristics as the flow rate characteristics. The curved surface portion 23 has a shape similar to the lower half of an egg, and its outer circumferential surface becomes gradually curved (with a larger curvature) from the upper end 23a to the lower end 23b.

[0005] In the flow control valve 1' designed to obtain such equal percentage characteristics, as shown by the thick arrow in FIG. 5, when the refrigerant flows from the valve chamber 6 to the valve orifice 15, the refrigerant flows along the curved surface portion 23. However, when passing through the valve orifice 15, sudden pressure fluctuations and refrigerant separation are likely to occur, which in turn makes it easier for vortices and cavitation to occur and grow, resulting in the problem of relatively loud noise.

[0006] Incidentally, providing the valve element 20 with an elliptical curved surface portion 23 in order to obtain the equal percentage characteristic as described above is problematic in terms of processing costs, cost-effectiveness, etc., so a flow control valve 1'' has been developed that is designed to obtain characteristics approximating the equal percentage characteristic, as shown in Fig. 6. The illustrated flow control valve 1'' comprises a valve body 5 to which a valve chamber forming member 6A is fixed and which is provided with a valve orifice 17 consisting of a first valve orifice portion 17A consisting of a short cylindrical surface and a second valve orifice portion 17B consisting of a truncated cone surface, and to which a pipe fitting 14 to which a conduit is connected is connected to the lower outer periphery of the second valve orifice portion 17B, and a valve element 30 that changes the flow rate of the fluid flowing through the valve orifice 17 in accordance with the amount of lift from the valve seat 8.

[0007] The valve body 30 has a seating surface portion 32 that seats on the valve seat 8, and a curved surface portion 33 that is connected to the lower side of the seating surface portion 32 and that provides flow characteristics that approximate equal percentage characteristics. The curved surface portion 33 has multiple stages (here, five stages) of conical tapered surface portions 33A-33E in which the control angle (the intersection angle with a line parallel to the central axis O of the valve body 30) is gradually increased toward the tip so as to simulate an ellipsoidal surface, and the first control angle θ1 of the uppermost conical tapered surface portion 33A is normally set to 3°<θ1<15° (here, 5°), and the lowermost conical tapered surface portion 33E is a pointed conical surface.

[0008] On the other hand, Patent Document 2 discloses a flow control valve that is designed to obtain normal linear characteristics, in which the dimensions and shape of the valve port are specified to suppress noise caused by pressure fluctuations and refrigerant separation phenomena when passing through the valve port, as described above. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2012-172839 A [Patent Document 2] Patent No. 5696093 Summary of the Invention [Problem to be solved by the invention]

[0010] However, in the flow control valve described in Patent Document 2, it is necessary to set the valve port length considerably long, which causes problems such as large pressure loss and difficulty in obtaining an appropriate refrigerant flow rate. Furthermore, since the dimensions and shape of the valve port are adapted to a valve body with linear characteristics, even if it is applied to a flow control valve having the above-mentioned equal percentage characteristics or characteristics similar thereto, a sufficient noise reduction effect cannot be obtained.

[0011] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a flow control valve that can effectively reduce noise caused by pressure fluctuations and refrigerant separation phenomena when passing through a valve port, and can also reduce pressure loss, etc. [Means for solving the problem]

[0012] To achieve the above object, the flow rate adjustment valve according to the present invention basically includes a valve body provided with a valve chamber and a valve port, a pipe joint having an inner diameter of D4 connected to the valve port, and a valve body designed to obtain an equal percentage characteristic or a characteristic approximating thereto as a flow rate characteristic and changing the flow rate of the refrigerant flowing through the valve port according to the lift amount. The valve port is provided with a first valve port portion of a cylinder having a diameter of D1, a second valve port portion of a cylinder having a diameter of D2, and a third valve port portion of a cylinder having a diameter of D3 in sequence from the valve chamber side, and D1 < D2 < D3 < D4. The first valve port portion is provided with a valve seat. An upper conical frustum-shaped tapered surface portion is formed between the first valve port portion and the second valve port portion, and a lower conical frustum-shaped tapered surface portion is formed between the second valve port portion and the third valve port portion. In the axial direction, the length of the lower conical frustum-shaped tapered surface portion is equal to or greater than the length of the upper conical frustum-shaped tapered surface portion. The taper angle of the upper truncated cone tapered surface portion is θu, and the taper angle of the lower truncated cone tapered surface portion is θv, where θu=θv. It is characterized by this.

[0013] In a preferred embodiment, the pipe joint is connected to the valve body such that at least the third valve port portion is disposed inside the pipe joint.

[0014] In another preferred embodiment, the valve body has a groove into which the end portion on the valve chamber side of the pipe joint is inserted, and the third valve port portion protrudes to the side opposite to the valve chamber side from the outer peripheral portion of the groove.

Effect of the Invention

[0015] In the flow rate adjustment valve according to the present invention, since the diameter of the valve port is sequentially increased in three or more stages from the valve chamber side to the lower end side, the refrigerant pressure gradually recovers when passing through the valve port, the pressure fluctuation is suppressed, and the rectification is achieved. Further, by setting (D2 / D1) and (D3 / D2) within a specific range, the generation and growth of vortices and cavitation associated with pressure fluctuations and refrigerant separation phenomena are suppressed. Furthermore, since (D2 / D1) < (D3 / D2) < (D4 / D3), the flow becomes smoother, so that in a flow rate adjustment valve having, for example, an equal percentage characteristic and a characteristic approximating thereto, the noise level can be made considerably low.

[0016] Furthermore, by setting (L2 / D1) and (L4 / D1) within a specific range, the valve port length L2 becomes shorter than that of the flow control valve 1' having equal percentage characteristics described in Patent Document 2 and shown in FIG. 5, so that the pressure loss is reduced and an appropriate refrigerant flow rate can be obtained. [Brief description of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view showing a main portion of an embodiment of a flow rate regulating valve according to the present invention; [Diagram 2] In order to confirm and verify the effects of the present invention, (A) a table showing actual measurement data of verification valves No. 1 to 4 with some changes in specifications and parameters, and (B) a table showing verification conditions A to G. [Diagram 3] (A) A graph showing the actual measured values ​​of verification valves No. 1 to 4 for each verification condition A to G, with the aperture ratio: D2 / D1 on the horizontal axis and the noise level [dB] on the vertical axis. (B) A graph showing the actual measured values ​​of verification valves No. 1 to 4 for each verification condition A to G, with the aperture ratio: D3 / D2 on the horizontal axis and the noise level [dB] on the vertical axis. [Figure 4] In order to confirm and verify the effects of the present invention, (A) a table showing actual measurement data for verification valves No. 5 to 8 with some of the specifications and parameters changed, (B) a table showing verification conditions H and I, and (C) a graph showing the actual measurement values ​​for verification valves No. 5 to 8 for each verification condition H and I, with the valve orifice length ratio: L4 / D1 on the horizontal axis and the sound pressure level [dB] on the vertical axis. [Diagram 5] FIG. 2 is a partial cross-sectional view showing a main portion of an example of a flow control valve configured to obtain an equal percentage characteristic. [Figure 6] 1A and 1B are partial cross-sectional views showing the main part of an example of a flow control valve configured to obtain characteristics approximating equal percentage characteristics, in which (A) is a partial cross-sectional view when the valve is closed, and (B) is a partial cross-sectional view when the valve is open. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0019] FIG. 1 is a cross-sectional view of the main part in an embodiment of a flow control valve according to the present invention. In FIG. 1, parts corresponding to each part of the conventional flow control valve 1'' shown in FIG. 6 described above are given common reference numerals.

[0020] The flow control valve 1 of the illustrated embodiment is configured to obtain characteristics approximated to the equal percentage characteristics, similar to the conventional flow control valve 1'' shown in FIG. 6 described above. A valve body 5 to which a valve chamber forming member 6A is fixed and which is provided with a valve port 10 (details will be described later), which is a characteristic part of the present invention, and a valve element 30 that changes the flow rate of the fluid flowing through the valve port 10 according to the lift amount from the valve seat 8 are provided. The valve element 30 has the same configuration as the conventional flow control valve 1'' shown in FIG. 6, and has a seating surface portion 32 that seats on the valve seat 8 and a curved surface portion 33 that is continuous with the lower side of the seating surface portion 32 and is configured to obtain characteristics approximated to the equal percentage characteristics as flow characteristics. The curved surface portion 33 has a plurality of (here, five) conical tapered surface portions 33A to 33E whose control angle (the intersection angle with a line parallel to the central axis O of the valve element 30) is gradually increased as approaching the tip so as to approximate an ellipsoid. The first control angle θ1 of the uppermost conical tapered surface portion 33A is set to 3° < θ1 < 15° (here, 5°), and the lowermost conical tapered surface portion 33E is a pointed conical surface.

[0021] The valve port 10 that opens into the valve chamber 6 sequentially includes a cylindrical first valve port portion 11 having a diameter of D1, a cylindrical second valve port portion 12 having a diameter of D2, and a cylindrical third valve port portion 13 having a diameter of D3 from the valve chamber 6 side. A pipe joint 14 having an inner diameter of D4 to which a conduit is connected is connected to the lower outer periphery of the third valve port portion 13. Here, D1 < D2 < D3 < D4, and the diameter of the valve port 10 is sequentially increased in three steps as it moves away from the valve chamber 6.

[0022] Here, in the present embodiment, (diameter ratio: D2 / D1) < (diameter ratio: D3 / D2) < (diameter ratio: D4 / D3), and (D2 / D1) and (D3 / D2) are each set within a specific range, that is, 1.08 < (D2 / D1) < 1.37 and 1.05 < (D3 / D2) < 1.43, based on prototype experiments and the like.

[0023] In addition, a truncated cone-shaped tapered surface portion 16 with a taper angle of θu is formed (at the step portion) between the first valve orifice portion 11 and the second valve orifice portion 12, and a truncated cone-shaped tapered surface portion 18 with a taper angle of θv is formed (at the step portion) between the second valve orifice portion 12 and the third valve orifice portion 13.

[0024] Furthermore, the orifice length (length in the direction of the central axis O) of the first orifice portion 11 is L1, the orifice length of the second orifice portion 12 is L2, the orifice length of the third orifice portion 13 is L3, and the length from the upper end of the second orifice portion 12 to the lower end of the third orifice portion 13 is L4, and the orifice length ratio: L2 / D1 and the orifice length ratio: L4 / D1 are each set within a specific range, i.e., 1.0<(L2 / D1)<2.0 and 2.3<(L4 / D1)<4.0, based on prototype experiments, etc.

[0025] In the flow control valve according to the present invention thus configured, the diameter of the valve port 10 is increased in three stages in sequence as it moves away from the valve chest 6, so that the refrigerant pressure gradually recovers as it passes through the valve port, suppressing pressure fluctuations and rectifying the flow. Also, by setting (D2 / D1) and (D3 / D2) within a specific range, the generation and growth of vortexes and cavitation due to pressure fluctuations and refrigerant separation phenomena are reliably suppressed. Furthermore, by making (D2 / D1)<(D3 / D2)<(D4 / D3), the flow becomes even smoother, so that the noise level can be significantly reduced in a flow control valve having equal percentage characteristics or characteristics similar thereto.

[0026] Furthermore, by setting (L2 / D1) and (L4 / D1) within a specific range, L2 (or L1) becomes shorter than that of the flow control valve 1' having equal percentage characteristics described in Patent Document 2 or shown in Figure 5, so that the pressure loss is reduced and an appropriate refrigerant flow rate can be obtained.

[0027] [Verification test to verify the appropriate range of aperture ratio and valve length ratio and its results] In order to confirm and verify the above-mentioned effects, the inventors prepared verification valves No. 1 to 4 with diameter ratios (D2 / D1), (D3 / D2) and verification valves No. 5 to 8 with orifice length ratios (L4 / D1) that were partially changed in specifications and dimensions as shown in the tables of Figure 2(A) and Figure 4(A), and conducted verification tests under conditions A to G shown in Figure 2(B) and conditions H and I shown in Figure 4(B). The test results of verification valves No. 1 to 4 with diameter ratios (D2 / D1), (D3 / D2) are shown in Figures 3(A) and (B), and the test results of verification valves No. 5 to 8 with orifice length ratios (L4 / D1) are shown in Figure 4(C).

[0028] Note that Figure 3(A) is a graph showing the actual measured values ​​of verification valves No. 1 to 4 for each verification condition A to G, with the aperture ratio: D2 / D1 on the horizontal axis and the noise level [dB] on the vertical axis; Figure 3(B) is a graph showing the actual measured values ​​of verification valves No. 1 to 4 for each verification condition A to G, with the aperture ratio: D3 / D2 on the horizontal axis and the noise level [dB] on the vertical axis; and Figure 4(C) is a graph showing the actual measured values ​​of verification valves No. 5 to 8 for each verification condition H and I, with the valve orifice length ratio: L4 / D1 on the horizontal axis and the sound pressure level [dB] on the vertical axis.

[0029] In addition, in the graphs of Figures 3(A), (B) and Figure 4(C), level 0 (reference) indicates the noise level and sound pressure level of a flow control valve 1'' (hereinafter referred to as the conventional product) having characteristics similar to the conventional equal percentage characteristics shown in Figure 6 described above.

[0030] From the graph in Figure 3(A), it can be seen that the noise level is lower than that of the conventional product when the aperture ratio: (D2 / D1) is 1.05 to 1.45 (almost the entire range shown in the graph), and the noise reduction effect is particularly large around valves No. 3 and No. 2. However, it was confirmed that if (D2 / D1) is within the range of 1.08 (aperture ratio of valve No. 4) to 1.37 (≒ (1.31 + 1.42) / 2, the aperture ratio roughly halfway between valves No. 2 and No. 1), it is possible to reduce noise considerably compared to the conventional product.

[0031] From the graph in Figure 3(B), it can be seen that the noise level is lower than that of the conventional product when the aperture ratio: (D3 / D2) is 1.00 to 1.50 (almost the entire range shown in the figure). The noise reduction effect is particularly large around valves No. 3 and No. 2. However, it was confirmed that if (D3 / D2) is within the range of 1.08 to 1.43 (≒ (1.35 + 1.50) / 2, the aperture ratio roughly halfway between valves No. 3 and No. 4), it is possible to reduce noise considerably compared to the conventional product.

[0032] From the graph in FIG. 4(C), it was confirmed that when the valve orifice length ratio: (L4 / D1) is 2.00 to 4.00 (almost the entire range shown in the graph), the sound pressure level is equal to or lower than that of the conventional product, and the noise reduction effect is particularly large around valve No. 6. However, when (L4 / D1) is within the range of 2.30 (larger than the valve orifice length ratio of valve No. 5) to 4.00 (valve orifice length ratio of valve No. 8), a noise reduction effect compared to the conventional product can be obtained (for example, under condition I, the sound pressure level is 2 dB or more lower than the standard).

[0033] Although illustrations are omitted, it has been confirmed that if the valve orifice length ratio: (L2 / D1) is within the range of 1.0 to 2.0, the sound pressure level is equal to or lower than that of conventional products, and a noise reduction effect is obtained compared to conventional products.

[0034] In the above embodiment, the present invention is described as being applied to a flow control valve 1 having characteristics approximating equal percentage characteristics, but this is not limited to this. The present invention can be applied not only to a flow control valve 1' having equal percentage characteristics as shown in FIG. 5, but also to flow control valves having linear characteristics as described in Patent Documents 1 and 2, etc.

[0035] In addition, in the above embodiment, the curved surface portion of the valve body is composed of a multi-stage conical tapered surface portion in which the control angle gradually increases toward the tip side, but this is not limited to this and may be an elliptical spherical surface portion as shown in Figure 5, or a configuration in which the lower end portion (elliptical crown portion) of the elliptical spherical surface portion is removed, or further, may be composed of a combination of an elliptical spherical surface portion and one or more conical tapered surface portions.

[0036] In the embodiment described above, the third valve orifice portion 13 is connected to the pipe fitting 14 having an inner diameter of D4. However, it goes without saying that the same effect as described above can be obtained even if a fourth valve orifice portion having an opening diameter of D4 is formed on the opposite valve chamber side of the third valve orifice portion 13. [Explanation of symbols]

[0037] 1 Flow control valve 5 Valve body 6 Valve chamber 10. Valve Orifice 11 First valve orifice 12 Second valve orifice 13 Third valve orifice 14 Pipe fittings 30 Valve body 33 Curved part D1 First valve orifice diameter D2: Diameter of the second valve orifice D3 Diameter of the third valve orifice D4 Pipe fitting inner diameter L1 Length of the first orifice L2: Length of the second orifice L3: Length of the third orifice L4 2nd to 3rd valve orifice length

Claims

1. a valve body provided with a valve chamber and a valve port; a pipe fitting connected to the valve port and having an inner diameter of D4; and a valve element designed to obtain equal percentage characteristics or characteristics similar thereto as flow characteristics and changing the flow rate of a refrigerant flowing through the valve port in accordance with an amount of lift; The valve port is provided with a first valve port portion having a cylinder with a diameter of D1, a second valve port portion having a cylinder with a diameter of D2, and a third valve port portion having a cylinder with a diameter of D3, in this order from the valve chest side, with D1<D2<D3<D4 being satisfied; the first valve port portion includes a valve seat; An upper stage truncated cone-shaped tapered surface portion is formed between the first valve port portion and the second valve port portion, and a lower stage truncated cone-shaped tapered surface portion is formed between the second valve port portion and the third valve port portion, In the axial direction, the length of the lower truncated cone-shaped tapered surface portion is equal to or greater than the length of the upper truncated cone-shaped tapered surface portion, A flow control valve characterized in that the taper angle of the upper truncated cone tapered surface portion is θu and the taper angle of the lower truncated cone tapered surface portion is θv, where θu = θv.

2. 2. The flow rate control valve according to claim 1, wherein the pipe joint is connected to the valve body such that at least the third valve port portion is disposed inside the pipe joint.

3. the valve body has a groove into which an end portion of the pipe joint on the valve chest side is inserted, 3. The flow rate regulating valve according to claim 1, wherein the third valve port portion protrudes beyond an outer circumferential portion of the groove toward a side away from the valve chamber.

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