Air inlet valve for air balance, air balance device and ultralow-temperature refrigerator

Abstract

The utility model relates to an air inlet valve for air balance, an air balance device and an ultralow-temperature refrigerator, and belongs to the technical field of refrigeration equipment. The air inlet valve comprises a valve body and a plugging piece. A valve cavity is formed in the valve body, and an air inlet and an air outlet connector are formed in the valve body. A guide part is arranged in the air inlet and divides the air inlet into a guide channel located in the guide part and an air inlet channel located between the guide part and the air inlet; the plugging piece is arranged in the valve cavity and comprises a sealing part and a guide part; the sealing part floats up and down in the valve cavity under the action of airflow flowing in from the air inlet channel, and falls to cover the air inlet to seal the air inlet channel without the action of airflow; the guide part is arranged in the guide channel and is in sliding fit with the guide channel; the top end of the guide part is connected to the bottom of the sealing part to move up and down along with the sealing part; the air inlet valve adopts the plugging piece with a novel structure and is provided with the guide structure for guiding the plugging piece to fall, and an air inlet with a relatively large size can be designed so as to meet the requirement of rapidly balancing air pressure.

Description

Technical Field

[0001] This utility model belongs to the field of refrigeration equipment technology, and particularly relates to an air intake valve, an air balancing device, and an ultra-low temperature freezer for air balancing. Background Technology

[0002] Ultra-low temperature freezers are special freezing devices mainly used for the preservation of high-value substances such as biological samples and pharmaceuticals. Their freezing temperature is typically -80°C or lower. During use, due to the large temperature difference between the inside and outside of the freezer, after opening the door to store or retrieve items and then closing it, a negative pressure will form inside the freezer due to the rapid drop in temperature, making it difficult to open the door again.

[0003] Existing ultra-low temperature freezers typically employ air balancing devices to balance the air pressure inside and outside the freezer when the door is closed. For example, patent CN216432203U discloses an air balancing device and a freezer containing it. This air balancing device is equipped with an air inlet valve, which has a valve chamber within its valve body. The valve body has an air inlet at the bottom that communicates with the outside and an air outlet on the side that communicates with the inside of the freezer. A float is installed inside the valve chamber. The float blocks the air inlet by falling freely, and when there is a pressure difference between the inside and outside of the freezer, it is driven to rise and open the air inlet. However, in order to ensure that the sealing component can block the air inlet after free fall, the air inlet valve uses a spherical float as the sealing component, and the bottom of the valve body is set to be hemispherical so that the position of the float can be adjusted if it does not fall into place. Due to the overall size limitation of the air inlet valve, the above-mentioned float position adjustment method results in a relatively small air inlet size. When the negative pressure is large, the balancing time is long. At the same time, the generated airflow velocity is large, the noise is large, and the impact force on the float and valve cavity is large. The float is made of metal, which increases the manufacturing cost.

[0004] Therefore, how to improve the adjustment method of the falling position of the sealing component in the intake valve to avoid the limitation of the intake port size design is a technical problem that urgently needs to be solved. Utility Model Content

[0005] To address the aforementioned technical problems, this utility model provides an air intake valve, an air balancing device, and an ultra-low temperature freezer for air balancing. The air intake valve adopts a novel sealing component and is equipped with a guide structure to guide the sealing component to fall. Furthermore, the guide structure design does not limit the design size of the air intake, allowing for the design of a relatively large air intake to meet the need for rapid air pressure balancing.

[0006] This utility model provides an intake valve for air balancing, comprising:

[0007] The valve body has a valve cavity inside, an air inlet at the bottom that communicates with the valve cavity, and an air outlet on the side that communicates with the valve cavity. A guide is provided inside the air inlet, which divides the air inlet into a guide channel located inside the guide and an air inlet channel located between the guide and the air inlet. Both the guide channel and the air inlet channel extend vertically.

[0008] A sealing element, disposed within the valve cavity, includes:

[0009] The sealing part floats up and down in the valve cavity under the action of the airflow flowing in from the air intake channel, and falls down to cover the air intake port to seal the air intake channel when there is no airflow.

[0010] The guide part is vertically disposed in the guide channel and slides in cooperation with the guide channel. Its top end is connected to the bottom of the sealing part so as to move up and down with the sealing part. The guide part always slides in cooperation with the guide channel during the movement of the guide part.

[0011] In this technical solution, a sealing component consisting of a sealing part and a guiding part is used. The sealing component is guided to fall by the cooperation of the guiding part and the guiding channel, which can ensure that the sealing part is fully in place after falling to seal the air intake channel. At the same time, the sealing component is guided to fall by the guiding part. This guiding method does not rely on the design of the bottom surface of the valve cavity and does not limit the design size of the air intake. The design of the air intake size can be increased to almost the bottom surface area of ​​the valve cavity to meet the need for rapid pressure balancing under greater negative pressure.

[0012] In some embodiments, the guide element is a guide tube, which is sleeved inside the air inlet. The outer wall of the guide tube is connected to the inner wall of the air inlet via a connector. The space inside the guide tube forms a guide channel, and the space between the outer wall of the guide tube and the inner wall of the air inlet forms an air intake channel. The guide portion of the sealing element passes through the guide channel, and the outer wall of the guide portion slides in conjunction with the inner wall of the guide tube. This technical solution uses a guide tube as the guide element, which facilitates the formation of a clear guide channel and air intake channel within the air inlet.

[0013] In some embodiments, the guide tube is located in the middle of the air inlet, and there are multiple connectors. These connectors divide the space between the outer wall of the guide tube and the inner wall of the air inlet into multiple air intake channels that are centrally symmetrically arranged with respect to the axis of the guide tube. This technical solution makes the airflow more evenly distributed when entering the valve cavity, and makes the force of the airflow on the sealing part of the sealing element more uniform, avoiding tilting or damage to the sealing part due to excessive local stress.

[0014] In some embodiments, the sealing part includes a sealing cap for completely covering the air inlet and a sealing ring covering the outer periphery of the sealing cap. The sealing ring fits against the outer edge of the air inlet to seal the outer edge of the air inlet. This technical solution can utilize the sealing cap that completely covers the air inlet to withstand the airflow force, while the sealing ring on the outer periphery of the sealing cap enhances the sealing effect.

[0015] In some embodiments, the top of the valve body has an installation port for installing a sealing component. The installation port communicates with the valve cavity, and a valve cover is sealed to the installation port to close it. This technical solution facilitates the installation of the sealing component by providing an installation port on the top of the valve body.

[0016] In some embodiments, the bottom of the valve cover is provided with a limiting member for abutting against the top of the sealing part to limit the maximum upward floating distance of the sealing member. The length of the sliding mating surface between the guide part and the guide channel is greater than the maximum upward floating distance of the sealing member. A gap is left between the limiting member and the air outlet port to allow airflow but prevent the sealing member from passing through, so that the floating of the sealing member is restricted within the valve cavity. This technical solution, by setting a limiting member to limit the maximum upward floating distance of the sealing member, can prevent the sealing member from detaching from the guide channel, and at the same time avoid the sealing member blocking the air outlet port.

[0017] Furthermore, this utility model also provides an air balancing device, including an air intake valve for air balancing as described in any of the above technical solutions, and an inner pipe connected to the axial outer end of the air outlet of the air intake valve. This technical solution connects to the equipment requiring air pressure balancing via the inner pipe, and achieves air pressure balancing through the air intake valve described in any of the above technical solutions. It can adapt to the need for rapid air pressure balancing under greater negative pressure, and has low noise.

[0018] In some embodiments, a sleeve is also included connecting the air outlet and the inner pipe. This technical solution uses a sleeve to connect the inner pipe and the air outlet of the air inlet valve. Different sizes of sleeves can be used to match different models of equipment, and maintenance is convenient.

[0019] In some embodiments, a heating wire is wrapped around the outer periphery of the sleeve. This technical solution, by incorporating a heating wire, is suitable for cryogenic equipment, thus avoiding ice blockage problems that may occur during prolonged use in low-temperature environments.

[0020] In addition, this utility model also provides an ultra-low temperature refrigerator, including a cabinet and a door connected to the cabinet, and further including the air balancing device described in any of the above technical solutions. An inner pipe is inserted into the foam layer of the door or cabinet, and the end of the inner pipe away from the air inlet valve is connected to the internal space of the cabinet. The air inlet valve is located on the outside of the door or cabinet, and the air inlet of the air inlet valve is connected to the external environment. This technical solution uses an air balancing device equipped with the air inlet valve described in any of the technical solutions to achieve air pressure balance, enabling rapid air pressure balance under high negative pressure, and with low noise.

[0021] Based on the above technical solutions, the air intake valve, air balancing device and ultra-low temperature freezer provided by this utility model adopt a sealing part consisting of a sealing part and a guiding part, and a guiding part is set at the air intake of the air intake valve. The sealing part is guided when it falls by the cooperation of the guiding part and the guiding part. This guiding method does not need to rely on the shape design of the bottom surface of the valve cavity, and does not limit the design size of the air intake. A relatively large air intake can be designed to meet the needs of rapid air pressure balancing. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of the present invention and form part of this application, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings:

[0023] Figure 1 A schematic diagram of the structure of an intake valve for air balancing provided in one embodiment of the present invention;

[0024] Figure 2 This is an assembly diagram of an air intake valve for air balancing provided in an embodiment of the present invention, showing the air intake passage sealed by the sealing part of the plugging component.

[0025] Figure 3 This is a schematic diagram of the assembly of an air intake valve for air balancing in the floating state of the sealing part of the plug, according to an embodiment of the present invention.

[0026] Figure 4 A schematic diagram of the valve body in an intake valve for air balancing provided in one embodiment of this utility model;

[0027] Figure 5 A schematic diagram of the structure of a sealing component in an intake valve for air balancing, provided in one embodiment of this utility model;

[0028] Figure 6 A schematic diagram of the valve cover in an intake valve for air balancing provided in one embodiment of this utility model;

[0029] Figure 7 This is a schematic diagram of the structure of an air balancing device provided in one embodiment of the present invention;

[0030] Figure 8 This is an assembly diagram of an air balancing device provided in one embodiment of the present invention;

[0031] Figure 9 This is a schematic diagram of the assembly of the air balancing device and the door in an ultra-low temperature refrigerator according to one embodiment of the present invention.

[0032] In the picture:

[0033] 1. Intake valve; 2. Inner pipe; 3. Sleeve; 4. Heating wire; 5. Door body;

[0034] 11. Valve body; 111. Guide component; 112. Connecting component; 12. Valve cover; 121. Limiting component; 13. Sealing component; 131. Sealing part; 1311. Sealing cover; 1312. Sealing ring; 132. Guide part;

[0035] 51. Foaming layer;

[0036] a. Valve chamber; b. Air inlet; b1. Air inlet channel; b2. Guide channel; c. Air outlet. Detailed Implementation

[0037] The technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0038] In the description of this utility model, it should be understood that the terms "upper," "lower," "vertical," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the appendix. Figure 2 The orientations or positional relationships shown are for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0039] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0040] As attached Figures 1-4As shown in an illustrative embodiment of the air intake valve 1 for air balancing of this utility model, the air intake valve 1 for air balancing includes a valve body 11 and a sealing member 13; the valve body 11 has a valve cavity a inside, an air inlet b communicating with the valve cavity a at its bottom, and an air outlet c communicating with the valve cavity a on its side; a guide member 111 is provided inside the air inlet b, the guide member 111 divides the air inlet b into a guide channel b2 located inside the guide member 111 and an air intake channel b1 located between the guide member 111 and the air inlet b, both the guide channel b2 and the air intake channel b1 are connected to the valve cavity a, and the guide channel b2 and the air intake channel b1 are connected to the valve cavity a. All extend vertically; the sealing element 13 is disposed in the valve cavity a, and includes a sealing part 131 and a guide part 132; the sealing part 131 floats up and down in the valve cavity a under the action of the airflow flowing in from the air intake channel b1, and falls down to cover the air intake port b to seal the air intake channel b1 when there is no airflow; the guide part 132 is disposed vertically in the guide channel b2 and slides in cooperation with the guide channel b2, and its top end is connected to the bottom of the sealing part 131 to move up and down with the sealing part 131. During the movement of the guide part 132, it always slides in cooperation with the guide channel b2 so as to constrain the movement direction of the guide part 132 and the sealing part 131 through the guide channel b2.

[0041] like Figure 2 and Figure 3 As shown, the working principle of the air intake valve 1 used for air balance is as follows: When there is a negative pressure on the side of the air outlet c of the valve body 11, creating a pressure difference between the side of the air outlet c and the side of the air inlet b, the airflow flows in through the air intake channel b1 of the air inlet b. The sealing part 131 of the sealing member 13 floats up under the action of the airflow. At the same time as the sealing part 131 floats up, it drives the guide part 132 to slide upward in the guide channel b2. The sliding cooperation between the guide part 132 and the guide channel b2 constrains the sealing part 131 to float up and down in the valve body 11 and prevents it from flipping. When the air pressure on the side of the air outlet c and the side of the air inlet b is balanced, the sealing member 13 falls freely. When the sealing member 13 falls, the guide channel b2 constrains the movement direction of the guide part 132 and the sealing part 131 to avoid the sealing part 131 from being displaced in the horizontal direction. This achieves the guidance of the sealing member 13 when it falls, ensuring that the sealing part 131 is fully in place after falling to seal the air intake channel b1.

[0042] In the aforementioned air intake valve 1 for air balancing, a sealing member 13 is employed, consisting of a sealing part 131 and a guide part 132. A guide part 111 is provided at the air intake port b to divide the air intake port b into an air intake channel b1 and a guide channel b2. The guide channel b2 cooperates with the guide part 132 of the sealing member 13 to guide the sealing member 13 as it falls, ensuring that the sealing part 131 is fully in place after falling to seal the air intake channel b1. This guide structure is simple. Furthermore, the air intake valve 1 for air balancing uses the guide part 111 to guide the sealing member 13 as it falls. This guide method does not rely on the bottom surface shape design of the valve cavity a, and does not limit the design size of the air intake port b. The size of the air intake port b can be increased to nearly the area of ​​the bottom surface of the valve cavity a to meet the need for rapid pressure balancing under greater negative pressure.

[0043] In some embodiments, such as Figures 2-4 As shown, the guide member 111 is a guide tube, which is sleeved inside the air inlet b. The outer wall of the guide tube is connected to the inner wall of the air inlet b through the connector 112. The space inside the guide tube forms a guide channel b2, and the space between the outer wall of the guide tube and the inner wall of the air inlet b forms an air intake channel b1. The guide portion 132 of the sealing member 13 passes through the guide channel b2, and the outer wall of the guide portion 132 slides with the inner wall of the guide tube. In this embodiment, a guide tube is used as the guide member 111, and the connector 112 is used to fix it inside the air inlet b, which facilitates the formation of a clear guide channel b2 and air intake channel b1 inside the air inlet b. This structure further simplifies the design of the guide member 111 and facilitates processing and assembly. At the same time, the sliding fit between the inner wall of the guide tube and the outer wall of the guide portion 132 can more accurately constrain the movement direction of the sealing member 13 and prevent the sealing member 13 from displacing in the horizontal direction.

[0044] In some embodiments, such as Figure 4 As shown, the guide tube is located in the middle of the air inlet b, and there are multiple connectors 112. These connectors 112 divide the space between the outer wall of the guide tube and the inner wall of the air inlet b into multiple air intake channels b1 that are centrally symmetrical about the axis of the guide tube. This design makes the airflow more evenly distributed when it enters the valve chamber a, and makes the force of the airflow on the sealing part 131 of the sealing member 13 more even, thus preventing the sealing part 131 from tilting or being damaged due to excessive local stress.

[0045] In some embodiments, such as Figure 2 and Figure 5As shown, the sealing part 131 includes a sealing cap 1311 for completely covering the air inlet b, and a sealing ring 1312 covering the outer periphery of the sealing cap 1311. The sealing ring 1312 fits against the outer edge of the air inlet b to seal the outer edge of the air inlet b. With the above-described structure, the sealing part 131 can withstand the airflow force by utilizing the sealing cap 1311 that completely covers the air inlet b. Simultaneously, the sealing ring 1312 around the sealing cap 1311 enhances the sealing effect, preventing airflow leakage from the gap between the sealing part 131 and the air inlet b. Furthermore, the elastic properties of the sealing ring 1312 can accommodate small displacements of the sealing member 13, ensuring good sealing performance under different operating conditions. It should be noted that with the above-described structure, the bottom inner wall of the valve cavity a of the sealing part 131 can be designed as a flat surface, without the need for a specially shaped valve cavity a, which facilitates the processing and manufacturing of the valve body 11.

[0046] In some embodiments, such as Figure 2 and Figure 6 As shown, the top of the valve body 11 has an installation port for installing the sealing element 13. The installation port is connected to the valve cavity a, and a valve cover 12 for sealing the installation port is sealed to the installation port. The installation port on the top of the valve body 11 facilitates the installation of the sealing element 13.

[0047] In some embodiments, such as Figure 3 and Figure 6 As shown, the bottom of the valve cover 12 is provided with a limiting member 121 for abutting against the top of the sealing part 131 to limit the maximum upward floating distance of the sealing member 13. The length of the sliding mating surface between the guide part 132 and the guide channel b2 is greater than the maximum upward floating distance of the sealing member 13, and a gap is left between the limiting member 121 and the air outlet c to allow airflow to pass through but prevent the sealing member 13 from passing through, so that the floating of the sealing member 13 is restricted within the valve cavity a. In this embodiment, by limiting the maximum upward floating distance of the sealing member 13 by the limiting member 121, it is possible to prevent the sealing member 13 from detaching from the guide channel b2, and at the same time, to prevent the sealing member 13 from blocking the air outlet c.

[0048] like Figure 7 and Figure 8 As shown, based on the aforementioned air intake valve 1 for air balancing, this utility model also provides an air balancing device, including the aforementioned air intake valve 1 for air balancing, and an inner pipe 2 connected to the outer end of the air outlet c of the air intake valve 1. This air balancing device is connected to the equipment requiring air pressure balancing via the inner pipe 2, and achieves air pressure balancing through the aforementioned novel air intake valve 1. It can adapt to the need for rapid air pressure balancing under greater negative pressure and has low noise.

[0049] In some embodiments, such as Figure 7 and Figure 8As shown, the air balancing device also includes a sleeve 3 connected between the air outlet c and the inner pipe 2. It should be noted that in this embodiment, the sleeve 3 is plugged into the air outlet c, and the sleeve 3 is threaded into the inner pipe 2. By connecting the inner pipe 2 and the air outlet c of the air inlet valve 1 through the sleeve 3, different sizes of sleeve 3 can be used to match different models of equipment, and maintenance is convenient.

[0050] In some embodiments, such as Figure 8 As shown, the outer periphery of the sleeve 3 is covered with a heating wire 4 to make it suitable for low-temperature equipment and avoid ice blockage problems caused by prolonged use in low-temperature environments.

[0051] like Figure 9 As shown, based on the aforementioned air balancing device, this utility model also provides an ultra-low temperature refrigerator, including a cabinet and a door 5 connected to the cabinet, and also including the aforementioned air balancing device. An inner pipe 2 passes through the foam layer 51 of the door 5, with the end of the inner pipe 2 away from the air inlet valve 1 connected to the internal space of the cabinet. The air inlet valve 1 is located on the outside of the door 5, and its air inlet b is connected to the external environment. This ultra-low temperature refrigerator uses an air balancing device equipped with the aforementioned novel air inlet valve 1 to achieve air pressure balance, enabling rapid air pressure balance under high negative pressure with low noise. It should be noted that the air inlet valve 1 is installed on the outside, facilitating maintenance and replacement, and improving the service life and reliability of the equipment. It should also be noted that when installing the air inlet valve 1, the air inlet b of the air inlet valve 1 should face downwards to ensure that the sealing component 13 can fall freely. It is understood that the inner pipe 2 can also pass through the foam layer 51 of the cabinet, with the air inlet valve 1 located on the outside of the cabinet.

[0052] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0053] The above embodiments are only used to illustrate the technical solution of this utility model and not to limit it; although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this utility model or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the technical solution claimed by this utility model.

Claims

1. An intake valve for air balancing, characterized in that, include: The valve body has a valve cavity inside, an air inlet at its bottom communicating with the valve cavity, and an air outlet on its side communicating with the valve cavity. A guide is provided inside the air inlet, which divides the air inlet into a guide channel located inside the guide and an air intake channel located between the guide and the air inlet. Both the guide channel and the air intake channel extend vertically. A sealing element, disposed within the valve cavity, includes: A sealing part, which floats up and down in the valve chamber under the action of airflow flowing in from the air intake passage, and falls down to cover the air intake to seal the air intake passage when there is no airflow. A guide portion is vertically disposed within the guide channel and slides in cooperation with the guide channel. Its top end is connected to the bottom of the sealing portion so as to move up and down with the sealing portion. The guide portion always slides in cooperation with the guide channel during its movement.

2. The intake valve for air balancing according to claim 1, characterized in that, The guide is a guide tube, which is sleeved inside the air inlet. The outer wall of the guide tube is connected to the inner wall of the air inlet through a connector. The space inside the guide tube forms the guide channel, and the space between the outer wall of the guide tube and the inner wall of the air inlet forms the air intake channel. The guide part of the sealing member passes through the guide channel, and the outer wall of the guide part slides in conjunction with the inner wall of the guide tube.

3. The intake valve for air balancing according to claim 2, characterized in that, The guide tube is located in the middle of the air inlet, and there are multiple connectors. The multiple connectors divide the space between the outer wall of the guide tube and the inner wall of the air inlet into multiple air intake channels that are centrally symmetrical with respect to the axis of the guide tube.

4. The intake valve for air balancing according to claim 1, characterized in that, The sealing part includes a sealing cap for completely covering the air inlet and a sealing ring covering the outer periphery of the sealing cap, the sealing ring being fitted with the outer edge of the air inlet to seal the outer edge of the air inlet.

5. The intake valve for air balancing according to claim 1, characterized in that, The valve body has an installation port at the top for installing the sealing component. The installation port is connected to the valve cavity, and a valve cover for sealing the installation port is sealed to the installation port.

6. The intake valve for air balancing according to claim 5, characterized in that, The bottom of the valve cover is provided with a limiting member for abutting against the top of the sealing part to limit the maximum upward floating distance of the sealing member. The length of the sliding mating surface between the guide part and the guide channel is greater than the maximum upward floating distance of the sealing member. A gap is left between the limiting member and the air outlet for airflow to pass through but for the sealing member to not pass through, so that the floating of the sealing member is restricted within the valve cavity.

7. An air balancing device, characterized in that, It includes an intake valve for air balancing as described in any one of claims 1-6, and an inner pipe connected to the outer axial end of the outlet port of the intake valve.

8. The air balancing device according to claim 7, characterized in that, It also includes a sleeve connecting the air outlet and the inner tube.

9. The air balancing device according to claim 8, characterized in that, The outer periphery of the sleeve is covered with a heating wire.

10. An ultra-low temperature freezer, comprising a cabinet and a door connected to the cabinet, characterized in that, It also includes the air balancing device according to any one of claims 7-9, wherein the inner tube is inserted into the foam layer of the door or the box, one end of the inner tube away from the air inlet valve is connected to the internal space of the box, the air inlet valve is located on the outside of the door or the outside of the box, and the air inlet of the air inlet valve is connected to the external environment.

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