Electric valve

Abstract

The purpose of the present invention is to prevent uneven wear of a fitting groove while suppressing wear of the fitting groove. The electrically operated valve includes: a valve body having a valve chamber therein that connects a first flow path and a second flow path; a valve body that moves forward and backward with respect to a valve seat formed in the valve chamber; a motor for driving the valve body; a speed reduction mechanism for reducing the rotation speed of the motor; an output shaft for outputting the rotation decelerated by the speed reduction mechanism; and a transmission mechanism that converts the rotational motion of the output shaft into a linear motion and transmits the linear motion to the valve body. The transmission mechanism has: a screw feed member that has a plate-shaped part and a male screw part formed on the outer peripheral surface, the plate-shaped part being fitted into a slit-shaped fitting groove formed in the output shaft so as to be capable of moving up and down; and a bearing member having a female thread portion screwed to the male thread portion. The interior of the fitting groove is provided with a relief portion that communicates with the fitting groove and is capable of receiving the tip of the plate-shaped portion in a non-contact state.

Description

Technical Field

[0001] The utility model relates to an electric valve, in particular to the structure of a power transmission part of a gear type electric valve. Background Art

[0002] Conventionally, electric valves that adjust the valve opening using an electric motor such as a stepping motor to control the flow rate of refrigerant have been used in refrigeration cycle devices including refrigerant circuits, such as air conditioners and refrigerators / freezers.

[0003] In addition, as such an electric valve, there is a gear type electric valve. Figures 5 to 7 Figures 41 illustrate an example of a gear-type electric valve. As shown in these figures, the electric valve 41 includes: a valve body 12, which internally includes a valve chamber 13 communicating with a first flow tube 14 and a second flow tube 15; a valve element 18 that moves forward and backward relative to a valve seat 16 formed within the valve chamber 13; a motor 31 that drives the valve element 18; a reduction mechanism (single planetary gear reduction mechanism) 21 that reduces the rotation of the motor 31; an output shaft 22 that outputs the rotation reduced by the reduction mechanism 21; and a transmission mechanism 23 that converts the rotation of the output shaft 22 into linear motion and transmits it to the valve element 18.

[0004] The transmission mechanism 23 includes a thread feed member 25 and an internally threaded portion 24a. The thread feed member 25 has a plate-shaped portion 25c that fits vertically into a slit-shaped fitting groove 22a formed in the output shaft 22. The internally threaded portion 24a is formed on the lower inner surface of the center hole of the bearing member 24. The thread feed member 25 has an externally threaded portion 25a on its outer circumference, which screws into the internally threaded portion 24a of the bearing member 24. These externally threaded portions 25a and internally threaded portions 24a form a thread feed mechanism. Therefore, when the rotation of the output shaft 22 is transmitted to the thread feed member 25 via the fitting groove 22a and the plate-shaped portion 25c, the thread feed member 25 rotates and moves vertically. The vertical motion of the thread feed member 25 is then transmitted to the valve element 18 via the ball joint 26.

[0005] In addition, as a document disclosing such an electric valve, there is the following Patent Document 1.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2017-9025.

[0009] Technical problems to be solved by utility models

[0010] However, in the previous electric valve 41, as the valve core 18 moves up and down, the plate-like portion 25c of the threaded feed component 25 slides in the up and down direction in the fitting groove (hereinafter sometimes simply referred to as "groove") 22a of the output shaft 22. Therefore, due to years of use, the fitting groove 22a sometimes wears out.

[0011] Here, while the lower portion (entrance) of the fitting groove 22a is always in contact with the plate-shaped portion 25c, the upper portion (inner portion) of the fitting groove 22a only contacts the plate-shaped portion 25c when the plate-shaped portion 25c is raised. As a result, the lower portion of the groove is cut more deeply, while the upper portion is cut less, resulting in uneven wear of the fitting groove 22a. Consequently, conventionally, this could cause looseness between the output shaft 22 and the thread feed member 25 (plate-shaped portion 25c), or reduce the coaxiality between the output shaft 22 and the thread feed member 25.

[0012] Furthermore, the portion of the plate-like portion 25c that contacts the corner portion 25d at the top (upper end) is pushed upward in the fitting groove 22a when the screw feeding member 25 ascends, and is easily cut by the corner portion 25d, thus also having a surface that is easily worn. Utility Model Content

[0013] Therefore, an object of the present invention is to suppress wear of the fitting groove and prevent the fitting groove from being unevenly worn.

[0014] Technical means for solving technical problems

[0015] and a valve core, the valve core being adapted to move forward and backward relative to a valve seat formed in the valve chamber; a motor driving the valve core; a reduction mechanism which reduces the speed of the motor; an output shaft which outputs the rotation reduced by the reduction mechanism; a transmission mechanism which converts the rotational motion of the output shaft into linear motion and transmits it to the valve core, the transmission mechanism comprising: a threaded feed component having a plate-shaped portion and an external threaded portion formed on an outer peripheral surface, the plate-shaped portion being embedded in a slit-shaped fitting groove formed on the output shaft in a manner capable of moving up and down; and a bearing component having an internal threaded portion which is screwed into the external threaded portion, wherein an avoidance portion is provided in the inner part of the fitting groove, the avoidance portion being connected to the fitting groove and capable of receiving the top end of the plate-shaped portion in a non-contact state.

[0016] In addition, in this application, the direction from the valve seat toward the valve core is referred to as "up," and the direction from the valve core toward the valve seat is referred to as "down." Based on these concepts of "up" and "down," terms related to up and down, such as "above" or "below," "upper" or "lower," "upper side," or "lower side," are used. However, the electric valve of the present invention (and the embodiments described below) can be used in various orientations. Therefore, it is not necessarily limited to "down" being the direction of gravity and "up" being the direction opposite to gravity.

[0017] The electric valve of the present invention is a gear-type flow control valve that controls the flow of fluids such as refrigerants. Like the conventional electric valves described above, it has a threaded feed component and a bearing component as a transmission mechanism for transmitting the driving force of the motor to the valve core. Furthermore, when the rotation of the output shaft is transmitted to the threaded feed component via the interlocking groove and the plate-like portion, the threaded feed component moves up and down due to the action of the threaded feed consisting of the external threaded portion formed on the outer circumference of the threaded feed component and the internal threaded portion of the bearing component. The up and down movement of the threaded feed component is then transmitted to the valve core, causing it to move in the up and down direction. This changes the gap between the valve core and the valve seat, and the flow rate of the fluid.

[0018] On the other hand, in the electric valve of the present invention, the escape portion is provided inside (upper) the fitting groove of the output shaft. More specifically, the fitting groove is on the lower side, and the escape portion is on the upper side. The fitting groove and the escape portion are formed on the output shaft so that they are interconnected and arranged in the vertical direction.

[0019] The above-mentioned avoidance portion prevents the top (upper) corner of the plate-like portion from contacting the inner surface of the fitting groove (moving up and down while in contact), and prevents the contact state between the fitting groove and the plate-like portion in the up and down directions from changing (or changing less) with the opening and closing action of the valve (i.e., the up and down movement of the threaded feed component), thereby preventing the fitting groove from being unevenly worn in the up and down directions.

[0020] More specifically, by providing a relief portion at the top of the engaging groove, the portion of the engaging groove that the plate-like portion contacts or does not contact is reduced as the plate-like portion moves up and down, thereby correspondingly improving the degree of uneven wear of the engaging groove. In particular, in a preferred embodiment of the present invention, in the valve closed state (i.e., when the plate-like portion is in the lowest position), the top end (upper end or upper surface) of the plate-like portion is arranged inside the relief portion. According to such an embodiment, the engaging groove is always in contact with the plate-like portion over the entire length in the vertical direction, and the contact state between the engaging groove and the plate-like portion in the vertical direction does not change with the opening and closing action of the valve (the up and down movement of the threaded feed component), thereby eliminating the uneven wear of the engaging groove in the vertical direction. In addition, according to this embodiment, the top corner of the plate-like portion that is prone to wear of the engaging groove is always located within the relief portion and does not contact the engaging groove, thereby suppressing the wear of the engaging groove.

[0021] Furthermore, in the above-mentioned previous electric valve, the higher the threaded feed component rises, the larger the contact area with the fitting groove becomes, and the sliding resistance increases. In contrast, according to the above-mentioned preferred method, the contact area of ​​the plate-like portion relative to the fitting groove no longer changes according to the position of the threaded feed component in the up and down directions, so the sliding resistance of the threaded feed component can be kept constant.

[0022] Effect of utility model

[0023] According to the present invention, it is possible to suppress wear of the fitting groove and prevent the fitting groove from being unevenly worn.

[0024] Other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention based on the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a longitudinal sectional view showing an electric valve (valve closed state) according to one embodiment of the present invention.

[0026] Figure 2 It is a longitudinal sectional view showing the electric valve (fully opened state) according to the above embodiment.

[0027] Figure 3 It is a longitudinal sectional view showing the output shaft and the screw feeding member of the electric valve in the valve closed state according to the above embodiment.

[0028] Figure 4 It is a longitudinal sectional view showing the output shaft and the screw feeding member of the electric valve according to the embodiment in the valve open (fully open) state.

[0029] Figure 5 This is a longitudinal sectional view showing an example of a conventional electric valve (valve closed state).

[0030] Figure 6 It is a longitudinal sectional view showing the output shaft and the screw feed member of the conventional electric valve in the valve closed state.

[0031] Figure 7 It is a longitudinal sectional view showing the output shaft and the screw feed member of the conventional electric valve in the valve open (fully open) state.

[0032] Explanation of symbols

[0033] A center axis

[0034] F Refrigerant flow

[0035] 11, 41 electric valve

[0036] 12 valve body

[0037] 12a Main body

[0038] 12b connection part

[0039] 12c step

[0040] 12d step

[0041] 13 valve chamber

[0042] 14First flow tube

[0043] 15 Second flow path tube

[0044] 16 valve seat

[0045] 17 throttle holes

[0046] 18 valve core

[0047] 18a flange

[0048] 18b fitting hole

[0049] 19 base board

[0050] 20 housing 21 speed reduction mechanism

[0051] 22 output shaft

[0052] 22a fitting groove

[0053] 22b Avoidance Section

[0054] 23 transmission mechanism

[0055] 24 bearing components

[0056] 24a internal thread

[0057] 24b embedded jack

[0058] 25 thread feed parts

[0059] 25a external thread

[0060] 25b cylindrical part

[0061] 25c plate part

[0062] 25d corner

[0063] 26 ball joints

[0064] 26a ball

[0065] 26b ball receiving seat

[0066] 27 valve core guide component

[0067] 27a guide part

[0068] 27b large diameter part

[0069] 27c flange

[0070] 27d step

[0071] 28 compression coil spring

[0072] 31 electric motor

[0073] 32 stator

[0074] 33 rotors

[0075] 34 yoke

[0076] 35 winding rack

[0077] 36 coils

[0078] 37 resin molded cover

[0079] 38 supporting shaft component

[0080] 39 supporting components. DETAILED DESCRIPTION

[0081] Reference Figures 1 to 4 , an electric valve according to one embodiment of the present invention will be described. In each figure, mutually orthogonal two-dimensional coordinates representing the vertical and horizontal directions are appropriately indicated, and the following description will be based on these directions. Furthermore, while the terms "vertical" and "horizontal" may be mentioned, the vertical direction corresponds to the vertical direction, and the direction orthogonal to the vertical direction is the horizontal direction, which includes the horizontal direction.

[0082] like Figures 1 to 4As shown, an electric valve 11 of one embodiment of the present invention is a preferred electric valve used in a refrigeration cycle device such as a heat pump cooling and heating system to regulate the flow rate of refrigerant, and comprises: a valve body 12, which has a valve chamber 13 and a valve seat 16 inside; a valve core 18, which is configured to be able to move forward and backward (up and down) relative to the valve seat 16; a motor 31, which drives the valve core 18; a reduction mechanism 21, which reduces the rotation of the motor 31 (rotor 33 described later); a transmission mechanism 23, which converts the rotation reduced by the reduction mechanism 21 into linear motion and transmits it to the valve core 18; and a shell (sealed container) 20, which forms a closed space on the upper part of the valve body 12.

[0083] The valve body 12 includes a main body 12a and a cylindrical connecting portion 12b. The main body 12a forms a valve chamber 13 and extends upward from the upper end of the main body 12a to connect to the motor 31 (housing 20). A valve seat 16 is formed at the upper end of an orifice 17 that extends vertically through the bottom surface of the main body 12a. Furthermore, a first flow tube 14 (equivalent to the first flow path of the present invention) is connected to the bottom surface of the main body 12a, communicating with the valve chamber 13 via the orifice 17. Furthermore, a second flow tube 15 (equivalent to the second flow path of the present invention) is connected to the side of the main body 12a, communicating with the valve chamber 13. In this embodiment, the first flow tube 14 serves as the refrigerant inflow path, and the second flow tube 15 serves as the refrigerant outflow path. However, the reverse can be employed, with the second flow tube 15 serving as the inflow path and the first flow tube 14 serving as the outflow path.

[0084] The outer diameter of the connecting portion 12b is smaller than that of the main body 12a. Therefore, a step 12c is formed on the outer circumferential surface of the valve body 12 at the boundary between the main body 12a and the connecting portion 12b. The lower end of the housing 20 is joined (welded) to the step 12c via an annular base plate 19, integrating the housing 20 with the valve body 12. The housing 20 is a bottomless, covered, cylindrical component (open at the bottom and closed at the top) formed by stamping a metal plate (e.g., stainless steel).

[0085] In this embodiment, the motor 31 driving the valve element 18 is a stepping motor and includes a stator 32 disposed outside (outer circumference) of the housing 20 and a rotor 33 rotatably disposed inside (inner circumference) of the housing 20 .

[0086] The stator 32 includes a yoke 34 , a coil 36 formed by winding a winding wire around a bobbin 35 , and a resin mold cover 37 that covers the yoke 34 and the coil 36 .

[0087] On the other hand, the rotor 33 is rotatably supported by a round rod-shaped support shaft member 38 extending vertically along the central axis A in the center portion of the housing 20. The lower end of the support shaft member 38 is relatively rotatably fitted into the upper portion of an output shaft 22 (described later) that outputs the rotation of the rotor 33, and the upper end is supported by a support member 39 disposed in the upper portion of the interior of the housing 20.

[0088] The reduction mechanism 21 includes a singular planetary gear mechanism inside the rotor 33, which has a high reduction ratio and is advantageous for miniaturization. The rotation of the rotor 33 is decelerated by the reduction mechanism 21 and transmitted to the output shaft 22, which is located at the center of the lower surface of the rotor 33, and outputted from the output shaft 22.

[0089] A cylindrical bearing member 24 is disposed below the rotor 33, and the output shaft 22 is rotatably supported by the bearing member 24. The bearing member 24 is inserted into the connecting portion 12b of the valve body 12 and fixed.

[0090] An insertion hole 24b is formed in the center of the upper surface of the bearing component 24, into which the output shaft 22 is rotatably inserted. Meanwhile, an internally threaded portion 24a is formed in the lower center portion of the bearing component 24, and an externally threaded portion 25a formed on the outer circumference of the thread feed component 25 screws into the internally threaded portion 24a. The bearing component 24 (internal threaded portion 24a) and the thread feed component 25 (external threaded portion 25a) together form a thread feed mechanism and comprise the transmission mechanism 23, which converts the rotational motion supplied from the motor 31 via the reduction mechanism 21 into linear motion in the vertical direction and transmits it to the valve core 18.

[0091] Specifically, the thread feed member 25 comprises a cylindrical portion 25b, with the externally threaded portion 25a described above formed on its outer surface, and a flat-blade screwdriver-shaped plate portion 25c, which rises vertically upward from the upper surface of the cylindrical portion 25b. The plate portion 25c is inserted vertically and slidably into a slit-shaped fitting groove 22a provided at the lower end of the output shaft 22. The rotor 33 rotates with the output shaft 22 while maintaining a fixed vertical position, without moving vertically. This rotational motion is transmitted to the thread feed member 25 via the fitting groove 22a and the plate portion 25c. Therefore, the plate portion 25c provided on the thread feed member 25 slides vertically within the fitting groove 22a of the output shaft 22. As the rotor 33 rotates, the thread feed member 25 linearly moves vertically, even though the output shaft 22 does not move vertically.

[0092] In addition, a relief portion 22b is provided at the upper end portion (inner portion) of the fitting groove 22a. The relief portion 22b is communicated with the fitting groove 22a and receives the top end portion of the plate-shaped portion 25c in a non-contact state. The relief portion 22b is provided at the upper end portion of the fitting groove 22a in a manner communicated with the fitting groove 22a in the front-to-back direction (with respect to the fitting groove 22a). Figures 1 to 4 The cylindrical space (circular in cross section) extending in a direction perpendicular to the paper plane has a diameter greater than the groove width (the width in the left-right direction) of the fitting groove 22a and horizontally penetrates the output shaft 22. This relief portion 22b functions to maintain a constant contact area between the plate-like portion 25c and the output shaft 22 (the inner surface of the fitting groove 22a) as follows.

[0093] In the closed valve state (refer to Figure 1 and Figure 3 ), the upper surface of the plate-like portion 25c is located inside the escape portion 22b (bottom portion). On the other hand, when the valve is opened, the threaded feed component 25 rises, and the upper portion of the plate-like portion 25c moves upward to be inserted into the escape portion 22b. In addition, the upper end portion of the plate-like portion 25c inserted into the escape portion 22b does not contact any other components including the output shaft 22 (fitting groove 22a). On the other hand, the fitting groove 22a is always in contact with the plate-like portion 25c throughout the entire length in the up-down direction, and the contact state between the fitting groove 22a and the plate-like portion 25c in the up-down direction does not change with the opening and closing action of the electric valve 11 (the up-down movement of the threaded feed component 25). Therefore, the uneven wear of the fitting groove 22a in the up-down direction disappears.

[0094] Furthermore, the upper corner portion 25d of the plate-like portion 25c, which is susceptible to wear of the fitting groove 22a, is always located within the relief portion 22b and does not come into contact with the fitting groove 22a. This reduces wear of the fitting groove 22a compared to conventional designs. Furthermore, the contact area of ​​the plate-like portion 25c with the fitting groove 22a does not change depending on the vertical position of the threaded feed member 25. This maintains the sliding resistance of the threaded feed member 25 constant, enabling stable opening and closing of the electric valve 11 (vertical and horizontal movement of the threaded feed member 25).

[0095] While grease is typically applied between the fitting groove 22a and the plate-like portion 25c to reduce sliding resistance, the relief portion 22b can also function as a grease reservoir for pre-placed grease. Furthermore, wear powder may be generated by the sliding of the plate-like portion 25c over time, but this is accumulated and retained within the relief portion 22b. The presence of the relief portion 22b can also reduce the possibility of wear powder being trapped between the externally threaded portion 25a and the internally threaded portion 24a, or between the valve element 18 and the valve seat 16, adversely affecting their operation or causing valve leakage.

[0096] The vertical linear motion of the thread feed member 25 is transmitted to the valve core 18 via the ball joint 26 composed of a ball 26a and a ball receiving seat 26b. Furthermore, by interposing the ball joint 26, the thread feed member 25 does not transmit the rotational motion of the thread feed member 25, but only transmits the vertical linear motion to the valve core 18.

[0097] The valve core 18 is a cylindrical member having a needle-shaped (inversely conical) tip at its lower end that contacts and separates from the valve seat 16. The valve core 18 also has a flange 18a extending horizontally outward at its upper end. Furthermore, a fitting hole 18b is formed in the upper surface of the valve core 18, into which the ball receiving seat 26b is inserted.

[0098] A stepped, cylindrical valve guide member 27 is also provided within the valve chamber 13. This valve guide member 27 consists of a guide portion 27a with a smaller diameter (inner and outer diameters) formed at the lower end, an annular flange portion 27c extending horizontally outward from the upper end, and a larger diameter portion 27b with a larger diameter (inner and outer diameters) formed in the middle (between the guide portion 27a and the flange portion 27c). The guide portion 27a supports the valve element 18 for vertical sliding movement. The flange portion 27c is positioned so as to rest on a stepped portion 12d formed at the lower end of the inner circumferential surface of the connecting portion 12b of the valve body 12 and is held between the stepped portion 12d and the bearing member 24, thereby preventing vertical displacement of the valve guide member 27. Furthermore, a stepped portion 27d is formed on the inner circumferential surface of the valve guide member 27 between the larger diameter portion 27b and the guide portion 27a.

[0099] Furthermore, a compression coil spring 28 is provided inside the large diameter portion 27b, more specifically, in the gap between the outer circumferential surface of the valve element 18 and the inner circumferential surface of the large diameter portion 27b. This compression coil spring 28, interposed in a compressed state between the flange portion 18a of the valve element 18 and the stepped portion 27d of the valve element guide member 27, biases the valve element 18 upward (in the valve opening direction). This biases the valve element 18 against the threaded feed member 25 via the flange portion 18a of the valve element 18 and the ball joint 26. This vertically integrates the valve element 18, the ball joint 26, and the threaded feed member 25. Furthermore, during valve opening operation, the biasing force of the compression coil spring 28 is applied to the valve element 18 in addition to the driving force of the motor 31, thereby ensuring reliable valve opening.

[0100] In addition, in this embodiment, the center axis A of the valve body 12 (the main body 12a and the connecting portion 12b), the valve seat 16, the throttle hole 17, the valve core 18, the spherical joint 26, the bearing component 24, the housing 20 and the support shaft component 38, and the center axis (rotation axis) A of the rotor 33, the output shaft 22 and the threaded feed component 25 are consistent with each other.

[0101] The operation of the electric valve 11 according to this embodiment will be described below.

[0102] When current is supplied to the stator 32 (coil 36) to cause the rotor 33 to rotate Figure 1 When the valve is rotated in one direction in the closed state shown, the rotation of the rotor 33 is decelerated by the speed reduction mechanism 21 and then converted into linear motion by the transmission mechanism 23, and the screw feed member 25 is lifted upward. In conjunction with this, the valve core 18, which is pressed against the lower surface of the screw feed member 25 via the ball joint 26 by the force of the compression coil spring 28, is lifted upward, and the valve core 18 leaves the valve seat 16, and the refrigerant flowing into the valve chamber 13 through the first flow path 14 flows out of the second flow path 15 into the open valve state (see Figure 2 The amount of refrigerant passing through (refrigerant flow rate) in the valve-open state can be adjusted by the amount of rotation of the rotor 33 (the distance between the valve element 18 and the valve seat 16).

[0103] On the other hand, when current is supplied to the stator 32 (coil 36) to rotate the rotor 33 from the valve-open state in the direction opposite to the above-mentioned one direction, the rotation of the rotor 33 is converted into linear motion by the transmission mechanism 23, and the screw feed member 25 moves downward. Accompanying this downward movement, the valve core 18 moves downward. When the valve core 18 seats on the valve seat 16, the flow path between the first flow path pipe 14 and the second flow path pipe 15 is cut off, and the valve is closed (see Figure 1 ).

[0104] As mentioned above, although embodiment of this invention was described, this invention is not limited to these, It is obvious to those skilled in the art that various changes can be made within the range described in the claim.

[0105] For example, while the relief portion 22b has a circular cross-sectional shape in the above embodiment, it may have any cross-sectional shape as long as it can accommodate the upper end of the plate-shaped portion 25c in a non-contact state (not in contact with the upper end of the plate-shaped portion 25c). Furthermore, in the above embodiment, a singular planetary gear mechanism is provided as the speed reduction mechanism 21, but a planetary gear mechanism or other speed reduction mechanism other than the singular planetary gear mechanism may also be employed.

Claims

1. An electric valve having: a valve body having a valve chamber therein communicating with the first flow path and the second flow path; a valve core that moves forward and backward relative to a valve seat formed in the valve chamber; an electric motor driving the valve core; a speed reduction mechanism that reduces the speed of rotation of the electric motor; an output shaft for outputting the rotation decelerated by the speed reduction mechanism; as well as a transmission mechanism that converts the rotational motion of the output shaft into linear motion and transmits it to the valve core, The transmission mechanism comprises: a screw feeding member having a plate-shaped portion and an external threaded portion formed on an outer peripheral surface, the plate-shaped portion being fitted into a slit-shaped fitting groove formed in the output shaft in a manner capable of moving up and down; and a bearing component having an internal thread portion threadedly engaged with the external thread portion, It is characterized in that An escape portion is provided in an inner portion of the fitting groove. The escape portion is communicated with the fitting groove and can receive the top end portion of the plate-shaped portion in a non-contact state.

2. The electric valve according to claim 1, characterized in that The tip of the plate-shaped portion is disposed inside the escape portion in a valve closed state.

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