JP7610866B2 - Flow Control Valve - Google Patents

Description

The present invention relates to a flow control valve that includes a valve body that is provided with a valve chamber and a valve port (orifice), and a valve element that changes the flow rate of fluid that flows through the valve port according to the amount of lift, and in particular, to a flow control valve that is suitable for adjusting the refrigerant flow rate in a heat pump type heating and cooling system, etc.

The relationship between the valve opening (lift amount) and flow rate in a flow control valve, i.e., the flow rate characteristics, are well known to be linear characteristics and equal percentage characteristics. The linear characteristic is a characteristic in which the rate of change of flow rate in response to changes in the valve opening is constant, while the equal percentage characteristic is a characteristic in which the rate of change of the valve opening is proportional to the flow rate.

Figure 5 shows the main parts of an example of a flow control valve that is designed to obtain equal percentage characteristics. The illustrated flow control valve 1' is used to adjust the refrigerant flow rate in heat pump air conditioning systems and 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 flowing through the valve port 15 depending on 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 lifting drive mechanism consisting of a valve shaft with a male thread, a guide stem with a female thread, and a stepping motor, as described in Patent Document 1, for example.

The valve body 20 has a contact surface 22 that contacts the valve seat 8, and an elliptical curved surface 23 that is connected to the underside of the contact surface 22 and is used to obtain equal percentage flow characteristics. The curved surface 23 has a shape similar to the lower half of an egg, and its outer periphery is gradually curved (has a larger curvature) from the upper end 23a to the lower end 23b.

In a flow control valve 1' designed to obtain such equal percentage characteristics, as shown by the bold arrow in Figure 5, when the refrigerant flows from the valve chamber 6 to the valve port 15, the refrigerant flows along the curved surface 23. However, when passing through the valve port 15, sudden pressure fluctuations and refrigerant separation are likely to occur, which can lead to the generation and growth of vortices and cavitation, resulting in the problem of relatively loud noise.

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

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 to 33E in which the control angle (the intersection angle with a line parallel to the central axis O of the valve body 30) increases stepwise as it approaches the tip to simulate an ellipsoidal surface, and the first control angle θ1 of the uppermost conical tapered surface portion 33A is usually set to 3°<θ1<15° (here, 5°), and the lowermost conical tapered surface portion 33E is a pointed conical surface.

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.

JP 2012-172839 A Patent No. 5696093

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

The present invention was made in consideration of the above circumstances, and its purpose is to provide a flow control valve that can effectively reduce noise caused by pressure fluctuations and refrigerant separation when passing through the valve port, and can also reduce pressure loss, etc.

In order to achieve the above object, the flow control valve according to the present invention basically comprises a valve body provided with a valve chamber and a valve port, a pipe fitting connected to the valve port and having an inside diameter of D4, and a valve body designed to obtain equal percentage characteristics or characteristics similar thereto as flow characteristics and to change the flow rate of refrigerant flowing through the valve port in accordance with a lift amount, and the valve port is provided with, in order from the valve chamber side, a first valve port portion of a cylinder having an opening diameter of D1, a second valve port portion of a cylinder having an opening diameter of D2, and a third valve port portion of a cylinder having an opening diameter of D3, and 2 < D3 < D4, the first valve orifice has a valve seat, an upper stage truncated conical tapered surface portion is formed between the first valve orifice and the second valve orifice, and a lower stage truncated conical tapered surface portion is formed between the second valve orifice and the third valve orifice, a length of the lower stage truncated conical tapered surface portion in the axial direction is equal to or longer than a length of the upper stage truncated conical tapered surface portion, a taper angle of the upper stage truncated conical tapered surface portion is θu and a taper angle of the lower stage truncated conical tapered surface portion is θv, and θu = θv .

In a preferred embodiment, the pipe fitting is connected to the valve body such that at least the third valve port is disposed inside the pipe fitting.

In another preferred embodiment, the valve body has a groove into which the valve chamber side end of the pipe fitting is inserted, and the third valve port portion protrudes away from the valve chamber beyond the outer periphery of the groove.

In the flow control valve of the present invention, the diameter of the valve port is increased in three or more stages from the valve chamber side to the lower end side, so that the refrigerant pressure gradually recovers as it passes through the valve port, suppressing pressure fluctuations and rectifying the flow. In addition, 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, by making (D2/D1) < (D3/D2) < (D4/D3), the flow becomes even smoother, so that, for example, in a flow control valve with equal percentage characteristics or characteristics similar thereto, the noise level can be significantly reduced.

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

1 is a cross-sectional view showing a main portion of an embodiment of a flow rate regulating valve according to the present invention; In order to confirm and prove the effects of the present invention, (A) a list showing actual measurement data of verification valves No. 1 to 4 in which some of the specifications and parameters have been changed, and (B) a list showing verification conditions A to G. (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. In order to confirm and prove 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. 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. 1A and 1B are partial cross-sectional views showing the main parts 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.

The following describes an embodiment of the present invention with reference to the drawings.

Figure 1 is a cross-sectional view showing the main parts of one embodiment of a flow control valve according to the present invention. In Figure 1, parts corresponding to those of the conventional flow control valve 1'' shown in Figure 6 described above are given the same reference numerals.

The flow control valve 1 of the illustrated embodiment is designed to obtain characteristics similar to the equal percentage characteristics, similar to the conventional flow control valve 1'' shown in Figure 6 described above, and includes a valve body 5 to which a valve chamber forming member 6A is fixed and a valve orifice 10 (details will be described later), which is a characteristic feature of the present invention, and a valve body 30 that changes the flow rate of the fluid flowing through the valve orifice 10 depending on the lift amount from the valve seat 8. The valve body 30 has the same configuration as the conventional flow control valve 1'' shown in Figure 6, and has a seating surface portion 32 that seats on the valve seat 8 and a curved surface portion 33 that is connected to the underside of the seating surface portion 32 and is used to obtain flow characteristics similar to the 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) increases stepwise as it approaches the tip to simulate an ellipsoidal surface, and 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.

The valve orifice 10 that opens into the valve chamber 6 has, from the valve chamber 6 side, a cylindrical first valve orifice portion 11 with a diameter D1, a cylindrical second valve orifice portion 12 with a diameter D2, and a cylindrical third valve orifice portion 13 with a diameter D3. A pipe fitting 14 with an inner diameter D4 is connected to the lower outer periphery of the third valve orifice portion 13, to which a conduit is connected. Here, D1<D2<D3<D4, and the diameter of the valve orifice 10 is successively increased in three stages as it moves away from the valve chamber 6.

In this embodiment, the aperture ratio is D2/D1 < D3/D2 < D4/D3, and D2/D1 and D3/D2 are set within a specific range based on prototype experiments, i.e., 1.08 < D2/D1 < 1.37 and 1.05 < D3/D2 < 1.43.

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

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. The orifice length ratios L2/D1 and L4/D1 are set within specific ranges, i.e., 1.0<(L2/D1)<2.0 and 2.3<(L4/D1)<4.0, based on prototype experiments, etc.

In the flow control valve of the present invention configured as described above, the diameter of the valve port 10 is successively increased in three stages as it moves away from the valve chamber 6, so that the refrigerant pressure gradually recovers as it passes through the valve port, suppressing pressure fluctuations and rectifying the flow. In addition, 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 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 with equal percentage characteristics or characteristics similar thereto.

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' with equal percentage characteristics described in Patent Document 2 and shown in Figure 5, so pressure loss is reduced and an appropriate refrigerant flow rate can be obtained.

[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 Figures 2(A) and 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 for 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 for verification valves No. 5 to 8 with orifice length ratios (L4/D1) are shown in Figure 4(C).

Figure 3(A) is a graph showing the actual measurement 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 measurement 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(C) is a graph showing the actual measurement values of verification valves No. 5 to 8 for each verification condition H and I, with the valve length ratio: L4/D1 on the horizontal axis and the sound pressure level [dB] on the vertical axis.

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

From the graph in Figure 3 (A), it can be seen that when the aperture ratio: (D2/D1) is between 1.05 and 1.45 (almost the entire range shown in the figure), the noise level is lower than that of the conventional product, 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), the noise can be significantly reduced compared to the conventional product.

From the graph in Figure 3 (B), it can be seen that when the aperture ratio: (D3/D2) is between 1.00 and 1.50 (almost the entire range shown in the figure), the noise level is lower than that of the conventional product, and 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), the noise can be significantly reduced compared to the conventional product.

From the graph in Figure 4 (C), it can be seen that when the valve orifice length ratio: (L4/D1) is between 2.00 and 4.00 (almost the entire range shown in the figure), 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, it has been confirmed that 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 is obtained compared to the conventional product (for example, the sound pressure level is 2 dB or more lower than the standard under condition I).

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 achieved compared to conventional products.

In the above embodiment, the present invention is applied to a flow control valve 1 having characteristics similar to the equal percentage characteristics, but the present invention is not limited to this. The present invention can be applied not only to a flow control valve 1' having the 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.

In the above embodiment, the curved surface portion of the valve body is configured with 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. It may be configured with 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, it may be configured by combining an elliptical spherical surface portion with one or more conical tapered surface portions.

In addition, in the above embodiment, the third valve orifice portion 13 is connected to a pipe fitting 14 having an inner diameter of D4, but it goes without saying that the same effect can be obtained even if a fourth valve orifice portion having an opening diameter of D4 is formed on the opposite side of the valve chamber from the third valve orifice portion 13.

Reference Signs List 1 Flow rate control valve 5 Valve body 6 Valve chamber 10 Valve port 11 First valve port portion 12 Second valve port portion 13 Third valve port portion 14 Pipe joint 30 Valve body 33 Curved surface portion D1 Diameter of first valve port portion D2 Diameter of second valve port portion D3 Diameter of third valve port portion D4 Inner diameter of pipe joint L1 Valve port length of first valve port portion L2 Valve port length of second valve port portion L3 Valve port length of third valve port portion L4 Second to third valve port lengths

Claims (3)

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