Electronic expansion valve

Abstract

The present invention discloses an electronic expansion valve, comprising a valve body and a coil sleeved on the valve body, the valve body comprising: a first valve assembly, a second valve assembly and a valve seat, the second valve assembly is provided with a small valve opening, and the valve seat is provided with a large valve opening; the first valve assembly and the second valve assembly are each provided with a first sealing surface, the first sealing surfaces of the two can contact each other to form a first sealing pair for sealing the small valve opening, the second valve assembly and the valve seat are each provided with a second sealing surface, the second sealing surfaces of the two can contact each other to form a second sealing pair for sealing the large valve opening; the first valve assembly can move up and down to adjust the opening of the small valve opening, the second valve assembly can move up and down to adjust the opening of the large valve opening; the first valve assembly is provided with a guide portion, and the guide portion at least partially passes through the small valve opening. By adopting this scheme, the sudden change of the fluid area flowing through the small valve opening is weakened, the impact of the high-speed fluid on the small valve opening is reduced, the noise is reduced, and the user's comfort is improved.

Description

Technical Field

[0001] The invention relates to the technical field of refrigeration control, and in particular to an electronic expansion valve. Background Art

[0002] The previous electronic expansion valve structure, from the closed state to the initial small flow regulation state, produced obvious throttling due to the small opening at the valve port. Part of the fluid flowing through the valve port was greatly accelerated to produce a vortex of a specific frequency, forming abnormal noise, which affected the end-user's comfort.

[0003] Therefore, it is necessary to improve the electronic expansion valve to reduce noise and improve user comfort. Summary of the invention

[0004] To achieve the above object, the present invention provides an electronic expansion valve, which includes a coil and a valve body, wherein the coil is sleeved on the valve body, the valve body includes a first valve component, a second valve component and a valve seat, the second valve component is provided with a small valve opening, and the valve seat is provided with a large valve opening;

[0005] The first valve assembly and the second valve assembly are each provided with a first sealing surface, and the first sealing surfaces of the two can contact each other to form a first sealing pair for sealing the small valve opening; the second valve assembly and the valve seat are each provided with a second sealing surface, and the second sealing surfaces of the two can contact each other to form a second sealing pair for sealing the large valve opening;

[0006] The first valve assembly can move up and down under the electromagnetic force of the coil to adjust the opening of the small valve opening, and the second valve assembly can move up and down to adjust the opening of the large valve opening;

[0007] The first valve assembly is provided with a flow guide portion, and the flow guide portion at least partially passes through the small valve opening portion.

[0008] The adoption of this solution avoids a sudden change in the area of ​​the fluid flowing through the small valve opening, reduces the impact of high-speed fluid on the small valve opening, reduces noise, and improves user comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A three-dimensional diagram of an embodiment of a valve body of an electronic expansion valve provided by the present invention;

[0010] Figure 2 for Figure 1 Another perspective of the picture;

[0011] Figure 3 for Figure 1 AA sectional view, in which the small valve port is in the maximum opening state and the large valve port is in the minimum opening state;

[0012] Figure 4 for Figure 2 BB sectional view, in this figure, the small valve port part and the large valve port part are both in the minimum opening state;

[0013] Figure 5 for Figure 3 Enlarged view of the part within the dashed box;

[0014] Figure 6 for Figure 4 Enlarged view of the part within the dashed box;

[0015] Figure 7 It is a position diagram of the small valve port and the guide portion when the small valve port is in the maximum opening state;

[0016] Figure 8 is a three-dimensional diagram of the valve core;

[0017] Fig. 9 for Figure 8 CC section view;

[0018] Fig.10 is a three-dimensional diagram of a valve stem;

[0019] Fig.11 for Fig.10 DD section view;

[0020] Fig.12 is a three-dimensional diagram of a valve needle;

[0021] Fig.13 for Fig.12 A half-section view of

[0022] Fig.14 The noise characteristics of several area ratios of S1 and S are shown in the figure, where S1 is the flow area of ​​the small valve part at the maximum opening, and S is the sum of the flow areas of all flow channel parts.

[0023] The following are the descriptions of the reference numerals:

[0024] A first valve assembly, B second valve assembly, C transmission assembly;

[0025] M1 first sealing pair, M11 first sealing surface, M2 second sealing part, M21 second sealing surface;

[0026] T channel department;

[0027] 1 valve seat, 1a large valve port;

[0028] 2 valve core, 2a first inflow portion, 2b second inflow portion, 2c recessed portion, 2d first hole portion, 2e second hole portion, 2f third hole portion, 2g first step portion, 2h second step portion, 2i guide portion;

[0029] 3 valve stem, 3a flow guide portion, 3b first accommodating groove portion, 3c flow channel portion;

[0030] 4 sleeve, 4a limiting portion;

[0031] 5. First silencer;

[0032] 6 valve needle, 6a small valve opening portion, 6b stop portion, 6c second accommodating groove portion, 6d outflow portion;

[0033] 7 second silencer, 8 retaining ring, 9 spring, 10 screw rod, 11 threaded connector, 12 fastener, 13 limit seat, 14 bearing, 15 rotor, 16 fixing part, 17 valve body, 18 cover, 19 connector, 20 first connecting pipe, 21 second connecting pipe. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0035] like Figure 1-Figure 4 As shown, the electronic expansion valve includes a coil (not shown in the figure) and a valve body, the coil is sleeved on the outer periphery of the valve body, and the valve body includes a first valve component A, a second valve component B, a transmission component C, a valve seat 1, a spring 9, a valve body 17, a cover 18, a connecting piece 19, a first connecting pipe 20 and a second connecting pipe 21.

[0036] The first connecting pipe 20 and the second connecting pipe 21 are connected to the two connecting holes of the valve seat 1 respectively. The lower end of the valve body 17 is fixedly connected to the valve seat 1, and the upper end of the valve body 17 is fixedly connected to the lower end of the cover 18. The upper end of the valve body 17 is fixed with a connecting piece 19. The cover 18, the valve body 17 and the valve seat 1 are enclosed together to form a valve cavity. The first valve assembly A, the second valve assembly B, the transmission assembly C and the spring 9 are installed in the valve cavity. The spring 9 is supported between the first valve assembly A and the second valve assembly B.

[0037] The second valve assembly B is provided with a small valve opening 6a. The first valve assembly A and the second valve assembly B are each provided with a first sealing surface M11 (see Fig.11 and Fig.13 ), the two first sealing surfaces M11 can contact each other to form a first sealing pair M1 for sealing the small valve opening 6a. The first valve assembly A is connected to the transmission assembly C and can move up and down under the driving action of the transmission assembly C. The up and down movement of the first valve assembly A is used to adjust the opening of the small valve opening 6a.

[0038] The valve seat 1 is provided with a large valve opening 1a. The second valve assembly B and the valve seat 1 are each provided with a second sealing surface M21 (see Fig.13), the two second sealing surfaces M21 can contact each other to form a second sealing pair M2 for sealing the large valve opening 1a. The second valve assembly B can move up and down under the action of the fluid pressure difference between the first connecting pipe 20 and the second connecting pipe 21, and the opening of the large valve opening 1a is adjusted by the up and down movement of the second valve assembly B.

[0039] Specifically, during the upward movement of the first valve assembly A, the two first sealing surfaces M11 gradually move away from each other, so that the opening of the small valve opening 6a gradually increases. When the first valve assembly A moves upward to the limit position, the small valve opening 6a reaches the maximum opening.

[0040] During the downward movement of the first valve assembly A, the two first sealing surfaces M11 gradually approach each other, thereby gradually reducing the opening of the small valve opening 6a. When the first valve assembly A moves downward to the limit position, the two first sealing surfaces M11 fit in contact to form a first sealing pair M1. At this time, the small valve opening 6a is sealed by the first sealing pair M1, and the small valve opening 6a reaches the minimum opening.

[0041] During the upward movement of the second valve assembly B, the two second sealing surfaces M21 gradually move away from each other, so that the opening of the large valve opening portion 1a gradually increases. When the second valve assembly B moves upward to the limit position, the large valve opening portion 1a reaches the maximum opening.

[0042] During the downward movement of the second valve assembly B, the two second sealing surfaces M21 gradually approach each other, thereby gradually reducing the opening of the large valve opening 1a. When the second valve assembly B moves downward to the limit position, the two second sealing surfaces M21 fit in contact to form a second sealing pair M2. At this time, the large valve opening 1a is sealed by the second sealing pair M2 to reach the minimum opening.

[0043] like Figure 5-Figure 7 , the first valve assembly A is provided with a guide portion 3a, and the outer periphery of the guide portion 3a is provided with a guide surface for guiding the flow direction of the fluid. When the small valve opening portion 6a is in any opening state, the guide portion 3a at least partially passes through the small valve opening portion 6a, that is, when the small valve opening portion 6a is from the minimum opening to the maximum opening, the lower end surface of the guide portion 3a is always located below the upper end surface of the small valve opening portion 6a. This arrangement can reduce the sudden change of the fluid area flowing through the small valve opening portion 6a, reduce the impact of high-speed fluid on the small valve opening portion 6a, reduce noise, and improve the user's comfort.

[0044] like Figure 7As shown, when the small valve opening portion 6a is in the maximum opening state, the distance between the lower end surface of the guide portion 3a and the upper end surface of the small valve opening portion 6a is L, and the maximum bilateral distance between the opposite sides of the guide portion 3a and the inner peripheral surface of the small valve opening portion 6a is N. In the figure, N1 and N2 are the unilateral distances between the opposite sides of the guide portion 3a and the inner peripheral surface of the small valve opening portion 6a, respectively, and N is the sum of N1 and N2. The small valve opening portion 6a has a constant diameter section, and the inner diameter of the constant diameter section is D. Preferably, L and D satisfy: L≥0.25D, and N and D satisfy: N<D / 3. This design can make the operation noise of the valve body smaller.

[0045] like Figure 5 As shown, a channel portion T is formed between the outer periphery of the first valve assembly A and the inner wall surface of the valve seat 1 and the valve body 17. The first valve assembly A is provided with an inflow portion (2a and 2b in the figure), a first accommodating groove portion 3b and a flow channel portion 3c. The inflow portion (2a and 2b in the figure) is connected between the channel portion T and the first accommodating groove portion 3b, and the first accommodating groove portion 3b is connected between the inflow portion (2a and 2b in the figure) and the flow channel portion 3c, and the flow channel portion 3c is closer to the guide portion 3a than the first accommodating groove portion 3b. A first silencer 5 is installed in the first accommodating groove portion 3b.

[0046] The second valve assembly B is provided with a small valve opening 6a, a second accommodating groove 6c and an outflow portion 6d. The second accommodating groove 6c is connected between the small valve opening 6a and the outflow portion 6d, and a second muffler 5 is installed in the second accommodating groove 6c.

[0047] like Figure 5 As shown by the arrow curve in the figure, the fluid flow direction when the small valve mouth is open is: first connecting pipe 20 → channel portion T → inflow portion (2a and 2b in the figure) → first accommodating groove portion 3b → flow channel portion 3c → guide portion 3a → small valve mouth portion 6a → second accommodating groove portion 6c → outflow portion 6d → second connecting pipe 21.

[0048] When flowing through the first accommodating groove 3b and the second accommodating groove 6c, the first silencer 5 in the first accommodating groove 3b and the second silencer 6c in the second accommodating groove 6c are used to reduce noise, and when flowing through the guide portion 3a, the guide surface of the guide portion 3a is used to guide the liquid.

[0049] The number of the flow channel portion 3c can be one or more. Fig.10 ) Six flow channel portions 3c are provided. When multiple flow channel portions 3c are provided, it is preferred that each flow channel portion 3c is evenly arranged on the circumference of the guide portion 3a, that is, each flow channel portion 3c is arranged on the circumference surrounding the guide portion 3a and the interval angles of adjacent flow channel portions 3c are the same. This design can further disturb the fluid passing through the first silencer 5, thereby further reducing the noise.

[0050] The flow area of ​​the small valve port 6a in the maximum opening state is S1, the flow area of ​​all flow channel portions 3c is S, and the flow area of ​​a single flow channel portion 3c is S2. Preferably, S and S1 satisfy: S1≤S≤1.5S1, and S1 and S2 satisfy: S2<0.5S1. This design has a better effect of reducing noise. Fig.14 The noise characteristics of several area ratios of S1 and S are shown in the figure. It can be seen from the figure that the noise characteristics when S=S1 and S=1.4S1 are obviously better than the noise characteristics when S=2S1 and S=3S1.

[0051] like Figure 5 As shown, the first valve assembly A is provided with a limiting portion 4a, and the second valve assembly B is provided with a stop portion 6b. When the small valve mouth portion 6a is in the maximum opening state and the large valve mouth portion 1a is in the minimum opening state, the upper surface of the limiting portion 4a contacts the lower surface of the stop portion 6b, thereby limiting the maximum opening position of the small valve mouth portion 6a.

[0052] Specifically, Figure 5 or Figure 6 As shown, the first valve assembly A includes a valve core 2, a valve stem 3, a sleeve 4 and a first silencer 5. The valve core 2 is inserted into the valve seat 1 and the valve body 17. The valve core 2 is connected to the transmission assembly C and can move up and down relative to the valve seat 1 and the valve body 17 under the drive of the transmission assembly C. The valve stem 3 is installed inside the valve core 2. The upper end of the sleeve 4 is fixedly connected to the lower end of the valve core 2. The first silencer 5 is installed inside the valve stem 3. Since the valve stem 3, the sleeve 4 and the first silencer 5 are directly or indirectly connected to the valve core 2, they can move up and down with the valve core 2. The above-mentioned inflow portion (2a and 2b in the figure) is arranged on the valve core 2. The above-mentioned guide portion 3a, the first accommodating groove portion 3b and the flow channel portion 3c are arranged on the valve stem 3. The above-mentioned limit portion 4a is arranged on the sleeve 4.

[0053] The second valve assembly B includes a valve needle 6, a second silencer 7 and a retaining ring 8. The valve needle 6 is inserted into the valve core 2, and is in clearance with the valve core 2, and can move up and down under the action of the fluid pressure difference. The second silencer 7 and the retaining ring 8 are installed inside the valve needle 6, and can move up and down with the valve needle 6. The small valve port portion 6a, the stop portion 6b, the second accommodating groove portion 6c and the outflow portion 6d are arranged on the valve needle 6.

[0054] A first sealing surface M11 of the first sealing pair M1 is arranged on the valve stem 3, and another first sealing surface M11 is arranged on the valve needle 6. A second sealing surface M21 of the second sealing pair M2 is arranged on the valve seat 1, and another second sealing surface M21 is arranged on the valve needle 6. The spring 9 is disposed between the valve core 2 and the valve needle 6.

[0055] Detailed, such as Figure 8 and Fig. 9As shown, the valve core 2 is provided with two inflow parts: a first inflow part 2a and a second inflow part 2b. The first inflow part 2a is communicated with the channel part T. The second inflow part 2b is arranged inside the valve core 2, and communicates between the first inflow part 2a and the first accommodating groove part 3b. The outer periphery of the valve core 2 is provided with an inner concave part 2c, and the channel part T is formed between the inner concave part 2c and the inner circumferential surface of the valve seat 1 and the valve body 17. The outer periphery of the valve core 2 is also provided with a guide part 2i, and the guide part 2i is guided and matched with the inner circumferential surface of the valve seat 1 and the valve body 17, and the inner concave part 2c is concave compared with the guide part 2i.

[0056] like Fig. 9 As shown, the valve core 2 is provided with a first hole portion 2d, a second hole portion 2e, a third hole portion 2f, a first step portion 2g and a second step portion 2h. The valve stem 3 is connected to the first hole portion 2d, the transmission assembly C is connected to the second hole portion 2e, and the valve needle 6 passes through the third hole portion 2f and is in clearance fit with the third hole portion 2f. The upper end of the sleeve 4 abuts against the first step portion 2g, and the upper end of the spring 9 abuts against the second step portion 2h.

[0057] Detailed, such as Fig.10 and Fig.11 As shown, the lower part of the valve stem 3 forms the above-mentioned guide portion 3a, the upper part of the valve stem 3 forms the first accommodating groove portion 3b, and the flow channel portion 3c is arranged on the lower end wall of the first accommodating groove portion 3b. The guide surface of the guide portion 3a (also the outer peripheral surface of the guide portion 3a) is generally a conical surface with a larger upper portion and a smaller lower portion. A first sealing surface M11 of the first sealing pair M1 is arranged between the guide portion 3a and the lower end wall of the first accommodating groove portion 3b. The first accommodating groove portion 3b is fixedly connected to the first hole portion 2d of the valve core 2, which can be specifically an interference connection or a threaded connection.

[0058] Detailed, such as Fig.12 and Fig.13 As shown, the valve needle 6 passes through the third hole 2f of the valve core 2 and is in clearance with the third hole 2f of the valve core 2. The small valve opening 6a is arranged at the upper end of the valve needle 6, the second accommodating groove 6c is located below the small valve opening 6a, the outflow portion 6d is arranged below the second accommodating groove 6c, and the stop portion 6b is arranged on the outer periphery of the valve needle 6. Figure 6 The second silencer 7 is installed in the second accommodating groove portion 6c, and the retaining ring 8 is installed in the outflow portion 6d. The upper end of the retaining ring 8 abuts against the second silencer 7 to limit the position of the second silencer 7.

[0059] Specifically, Figure 3 or Figure 4 As shown, the transmission assembly includes a screw rod 10 , a threaded connector 11 , a fastener 12 , a limit seat 13 , a bearing 14 , a rotor 15 , and a fixing member 16 .

[0060] The screw rod 10 and the threaded connector 11 are connected by a threaded pair. The threaded connector 11 is fixedly connected to the valve core 2 by a fastener 12. The screw rod 10 and the rotor 15 are fixedly connected by a fixing member 16. The screw rod 10 is rotatably supported on the limit seat 13 through a bearing 14. The limit seat 13 is fixedly connected to the valve body 17. The limit seat 13 is provided with a limit surface, which contacts the bearing 14 and plays a role in limiting the upward and downward movement of the screw rod 10.

[0061] When the coil is energized, the rotor 15 is driven to rotate, which drives the screw rod 10 to rotate, drives the threaded connector 11 to move up and down, drives the valve core 2 to move up and down, and makes the first valve assembly A move up and down as a whole, thereby realizing the opening adjustment of the small valve port 6a.

[0062] The electronic expansion valve provided by the present invention is introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. An electronic expansion valve, comprising a coil and a valve body, wherein the coil is sleeved on the valve body. It is characterized in that The valve body comprises a first valve component (A), a second valve component (B) and a valve seat (1), the second valve component (B) is provided with a small valve opening (6a), and the valve seat (1) is provided with a large valve opening (1a); The first valve assembly (A) and the second valve assembly (B) are each provided with a first sealing surface (M11), and the first sealing surfaces (M11) of the two can contact each other to form a first sealing pair (M1) for sealing the small valve opening (6a); the second valve assembly (B) and the valve seat (1) are each provided with a second sealing surface (M21), and the second sealing surfaces (M21) of the two can contact each other to form a second sealing pair (M2) for sealing the large valve opening (1a); The first valve component (A) can move up and down under the electromagnetic force of the coil to adjust the opening of the small valve opening (6a), and the second valve component (B) can move up and down to adjust the opening of the large valve opening (1a); The first valve assembly (A) is provided with a flow guide portion (3a), and when the small valve opening portion (6a) is in any opening state, at least a portion of the flow guide portion (3a) passes through the small valve opening portion (6a); The first valve assembly (A) is provided with an inlet portion, a first accommodating groove portion (3b) and a flow channel portion (3c); a first silencer (5) is installed in the first accommodating groove portion (3b); the first accommodating groove portion (3b) is connected between the inlet portion and the flow channel portion (3c); the flow channel portion (3c) is closer to the guide portion (3a) than the first accommodating groove portion (3b); and the fluid flows through the inlet portion, the first accommodating groove portion (3b), the flow channel portion (3c) and the guide portion (3a) in sequence.

2. The electronic expansion valve according to claim 1, It is characterized in that When the small valve opening portion (6a) is in the maximum opening state, the distance between the lower end surface of the guide portion (3a) and the upper end surface of the small valve opening portion (6a) is L; the small valve opening portion (6a) has a constant diameter section, and the inner diameter of the constant diameter section is D; L and D satisfy: L≥0.25D.

3. The electronic expansion valve according to claim 2, It is characterized in that The maximum bilateral distance between the two opposite sides of the flow guide portion (3a) and the inner circumference of the small valve opening portion (6a) is N; N and D satisfy: N<D / 3.

4. The electronic expansion valve according to claim 1, It is characterized in that The number of the flow channel portions (3c) is one or more. When there are more than one flow channel portions (3c), each of the flow channel portions (3c) is evenly arranged on the peripheral side of the guide portion (3a).

5. The electronic expansion valve according to claim 4, It is characterized in that The flow area of ​​all the flow channel parts (3c) is S, the flow area of ​​the small valve opening part (6a) in the maximum opening state is S1, and S and S1 satisfy: S1≤S≤1.5S1.

6. The electronic expansion valve according to claim 5, It is characterized in that The flow area of ​​a single flow channel portion (3c) is S2, and S1 and S2 satisfy: S2<0.5S1.

7. The electronic expansion valve according to claim 1, It is characterized in that The first valve assembly (A) is provided with a limiting portion (4a), and the second valve assembly (B) is provided with a stopping portion (6b). When the small valve opening portion (6a) is in a maximum opening state and the large valve opening portion (1a) is in a minimum opening state, the upper surface of the limiting portion (4a) contacts the lower surface of the stopping portion (6b).

8. The electronic expansion valve according to claim 7, It is characterized in that The second valve assembly (B) is provided with a second accommodating groove (6c) and an outflow portion (6d), a second silencer (7) is installed in the second accommodating groove (6c), the second accommodating groove (6c) is connected to the small valve opening (6a) and the outflow portion (6d), and the fluid flows through the small valve opening (6a), the second accommodating groove (6c), and the outflow portion (6d) in sequence.

9. The electronic expansion valve according to claim 8, It is characterized in that The first valve assembly (A) comprises a valve core (2), the valve core (2) passes through the valve seat (1), the inflow portion is arranged on the valve core (2), a channel portion (T) is formed between the outer periphery of the valve core (2) and the valve seat (1), and the inflow portion is connected between the channel portion (T) and the first accommodating groove portion (3b).

10. The electronic expansion valve according to claim 9, It is characterized in that The first valve assembly (A) comprises a valve stem (3), the valve stem (3) is fixedly connected to the valve core (2), the upper part of the valve stem (3) forms the first accommodating groove portion (3b), the lower part of the valve stem (3) forms the guide portion (3a), the flow channel portion (3c) is arranged on the lower end wall of the first accommodating groove portion (3b), and a first sealing surface (M11) of the first sealing pair (M1) is arranged between the flow channel portion (3c) and the guide portion (3a).

11. The electronic expansion valve according to claim 10, It is characterized in that The first valve assembly (A) comprises a sleeve (4), the sleeve (4) is fixedly connected to the valve core (2), and the limit portion (4a) is arranged on the sleeve (4); the second valve assembly (B) comprises a valve needle (6), the valve needle (6) and the valve core (2) are clearance-matched, and the stop portion (6b) is arranged on the valve needle (6); a spring (9) is arranged between the valve needle (6) and the valve core (2).

12. The electronic expansion valve according to any one of claims 1 to 11, It is characterized in that The valve body further comprises a transmission assembly (C), the transmission assembly (C) comprising a screw rod (10), a threaded connector (11), a limit seat (13) and a rotor (15), the screw rod (10) and the threaded connector (11) being connected via a threaded pair, the threaded connector (11) being fixedly connected or limit-connected to the first valve assembly (A), the screw rod (10) being fixedly connected to the rotor (15), the limit seat (13) being fixed relative to the valve seat (1) and being capable of limiting the upward and downward movement of the screw rod (10).

13. The electronic expansion valve according to claim 12, It is characterized in that The valve body further comprises a valve body (17) and a cover shell (18); the valve body (17) is fixedly connected to the valve seat (1); the cover shell (18) is fixedly connected to the valve body (17); the valve body (17), the cover shell (18) and the valve seat (1) together enclose a valve cavity; the transmission assembly (C), the first valve assembly (A) and the second valve assembly (B) are installed in the valve cavity.

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