Nitrogen supply system

Abstract

The utility model relates to a nitrogen gas supply system, which comprises a nitrogen gas supply source, a plurality of supply main pipelines communicated with the fluid of the nitrogen gas supply source and overflow valves arranged in the supply main pipelines, each supply main pipeline is communicated to a nitrogen gas user group positioned in a closed plant, and the nitrogen gas user group comprises a plurality of nitrogen gas users; the excess flow valve is located outside the plant, and when the flow of the nitrogen flowing through the excess flow valve does not exceed a preset flow threshold value, the excess flow valve is kept in an open state, so that the nitrogen can be supplied to each nitrogen user; when the flow of the nitrogen flowing through the excess flow valve exceeds a preset flow threshold value, the excess flow valve is automatically switched to a closed state. According to the nitrogen supply system disclosed by the utility model, the overflow valves are arranged outside the closed factory building in each supply main pipeline, so that the nitrogen can be prevented from excessively leaking into the factory building when a leakage area exists at a nitrogen user.

Description

Technical Field

[0001] The utility model relates to the technical field of nitrogen supply, in particular to a nitrogen supply system. Background Art

[0002] Closed-loop plants typically contain numerous nitrogen users (for example, within an extrusion building, including large-bag unloading stations, additive daytime storage, filter receivers, and extruder users, all of which require nitrogen). These users frequently consume nitrogen, generating significant peak gas volumes. However, if a leak occurs at one or more of these nitrogen users within such a closed plant, large amounts of nitrogen could leak into the atmosphere and accumulate within the plant, potentially suffocating operators.

[0003] Various types of nitrogen supply systems are known in the prior art. These systems may include nitrogen supply pipelines, often with multiple pipelines for safety, efficiency, and redundancy considerations. However, these systems all overlook the potential risk of asphyxiation from excessive nitrogen leakage within enclosed factories, and fail to provide effective solutions to this potential risk. Utility Model Content

[0004] The present invention is proposed based on such background, and aims to provide an improved nitrogen supply system to overcome the above-mentioned and / or other problems existing in the prior art.

[0005] According to the present invention, a nitrogen supply system is provided, comprising a nitrogen supply source, a plurality of main supply lines fluidically connected to the nitrogen supply source, and an excess flow valve disposed in each of the main supply lines, wherein each of the main supply lines is connected to a corresponding nitrogen user group located in a sealed factory building, wherein the nitrogen user group includes a plurality of nitrogen users; wherein the excess flow valve is located outside the sealed factory building, and is configured such that: when the flow rate of nitrogen flowing through the excess flow valve does not exceed a predetermined flow threshold of the excess flow valve, the excess flow valve remains in an open state so that nitrogen can be supplied to each nitrogen user along each main supply line; and when the flow rate of nitrogen flowing through the excess flow valve exceeds the predetermined flow threshold, the excess flow valve automatically switches to a closed state.

[0006] As an embodiment, the predetermined flow rate threshold is selected to be equal to the maximum nitrogen consumption flow rate of all nitrogen users in the nitrogen user group connected to the corresponding main supply line within a same period.

[0007] As an embodiment, the predetermined flow rate threshold is selected to be greater than the maximum nitrogen consumption flow rate of all nitrogen users in the nitrogen user group connected to the corresponding main supply line during the same period.

[0008] As an embodiment, the predetermined flow rate threshold is selected to be equal to 1.1-1.3 times the maximum nitrogen consumption flow rate in the same period.

[0009] As an embodiment, the excess flow valve includes a valve housing and a valve body and a spring assembly arranged in the valve housing; wherein the valve housing is provided with an inlet intended to be fluidically connected to the nitrogen supply source, an outlet intended to be fluidically connected to a downstream nitrogen user group, and a valve seat arranged in the valve housing near the outlet; the valve body includes a valve stem and a valve disc; the spring assembly includes a spring arranged around the valve stem; wherein the excess flow valve is capable of remaining open when the pressure between the inlet side and the outlet side is balanced, and when there is an abnormal pressure drop between the inlet side and the outlet side that is greater than a predetermined value, the valve body of the excess flow valve is driven by the spring assembly so that the valve disc of the valve body abuts against the valve seat to close the outlet, and the predetermined value is associated with the predetermined flow threshold of the excess flow valve.

[0010] As an embodiment, a pressure balancing port is provided on the valve disc, and the pressure balancing port can balance the pressure on the inlet and outlet sides of the excess flow valve when the flow rate of nitrogen flowing through the excess flow valve is restored to not more than a predetermined flow threshold, thereby returning the excess flow valve to an open state.

[0011] As an embodiment, the abnormal pressure drop indicates that there are one or more leakage points at the nitrogen user group located in the closed plant or at the section of the main supply line located in the closed plant.

[0012] By adopting the nitrogen supply system according to the present invention, in a relatively closed factory building (such as an extrusion building), an excess flow valve for preventing excessive nitrogen is installed on the main supply line of the nitrogen supply, especially outside the closed factory building. When the nitrogen flow rate flowing through the excess flow valve exceeds a predetermined flow threshold, the excess flow valve can be actively cut off and kept closed, thereby preventing a large amount of nitrogen from leaking into the closed factory building and causing a risk of suffocation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The above and other features and advantages of the present invention will become more readily understood through the following description with reference to the accompanying drawings, in which:

[0014] Figure 1 is a schematic diagram of a nitrogen supply system according to an embodiment of the present invention;

[0015] Figure 2To set in Figure 1 A cross-sectional view of an excess flow valve in a nitrogen supply system; and

[0016] Figure 3 The present invention is a flowchart of a method for supplying nitrogen using a nitrogen supply system according to an embodiment of the present invention.

[0017] All drawings are schematic and not necessarily drawn to scale. In addition, they only show those parts necessary for illustrating the present invention, and other parts are omitted or only mentioned. That is, in addition to the parts shown in the drawings, the present invention may also include other parts. DETAILED DESCRIPTION

[0018] Embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, many specific details are set forth in order to enable those skilled in the art to more fully understand and implement the present invention. However, it will be apparent to those skilled in the art that the present invention may be implemented without some of these specific details. In addition, it should be understood that the present invention is not limited to the specific embodiments described. On the contrary, it is contemplated that the present invention may be implemented with any combination of the features and elements described below, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments and advantages are for illustrative purposes only and should not be regarded as elements or limitations of the claims unless expressly set forth in the claims. The terms "comprising" and "having" are intended to express an open-ended inclusion and mean that additional elements / components may be present in addition to the listed elements / components.

[0019] As mentioned in the background, if a leak exists at one or more nitrogen users within a sealed factory building (e.g., a leak in the nitrogen user's own structure or in the supply pipeline serving the nitrogen user), a large amount of nitrogen can leak into the atmosphere, potentially suffocating workers within the sealed building due to the accumulation of leaked nitrogen. To address this potential safety risk, the applicant has proposed an improved nitrogen supply system that effectively addresses this potential safety hazard.

[0020] Figure 1 The nitrogen supply system 1 according to the present invention comprises a nitrogen supply source 2 and a plurality of nitrogen supply sources 2 branching out from the nitrogen supply source 2 (e.g., Figure 1Four supply main lines 3 are shown in the figure. Each supply main line 3 is connected to a nitrogen user group 4 comprising multiple nitrogen users located within a sealed plant 6. For example, each supply main line 3 may be connected to multiple supply sub-lines (not specifically shown in the figure). These supply sub-lines are connected to the multiple nitrogen users in a one-to-one correspondence, thereby achieving fluid connection between each supply main line 3 and the multiple nitrogen users.

[0021] In order to avoid the suffocation hazard caused by nitrogen leakage in the closed plant 6, an overflow valve 5 is installed on each supply main line 3 upstream of the nitrogen user group 4. Figure 1 As shown, the excess flow valve 5 is located outside the sealed factory building. This arrangement is highly advantageous because it effectively prevents the excess flow valve from closing immediately if a leak occurs in the factory building area downstream of the excess flow valve, thereby preventing nitrogen asphyxiation risks for employees within the factory building. When the nitrogen flow rate through the excess flow valve 5 within the main supply line 3 does not exceed a predetermined flow threshold, the excess flow valve 5 remains open, allowing nitrogen to be supplied to individual nitrogen users along the various main supply lines 3. However, when the nitrogen flow rate through the excess flow valve 5 within the main supply line 3 exceeds the predetermined flow threshold, the excess flow valve 5 automatically switches to a closed state. For example, if the flow rate upstream of the excess flow valve 5 increases abnormally, resulting in an abnormally increased pressure drop between the inlet and outlet of the excess flow valve 5, this may indicate a leak at a nitrogen user group or in the section of the main supply line 3 within the sealed factory building 6. By installing this excess flow valve, excessive nitrogen leakage into the factory building 6 can be prevented when a leak or damage point exists within a nitrogen user group.

[0022] In actual application scenarios, for example, in a nitrogen supply system 1 for a closed extrusion building, four supply main lines 3 can be set, which correspond to four different user groups SCD031 to SCD034 (see Figure 1 ), each user group includes multiple different sub-users. In addition, four overflow valves 5 are installed outside the extrusion building to ensure that all nitrogen users within the extrusion building receive nitrogen from downstream of these overflow valves. Next, we will detail the setting of the predetermined flow threshold for each overflow valve based on the nitrogen usage of different user groups.

[0023] SCD031 User Group: For the sub-users included in this user group (e.g., all additive daytime bins and filter receivers, additive loss-in-weight scale filters, extruder feed hoppers, and extruder screw seals), all sub-users are included in the flow calculation, except for half of the sub-users marked with * in Table 1 (e.g., only half of the sub-users (e.g., filter receivers) perform backflush). The resulting total is the predetermined flow threshold for the overflow valve for this user group.

[0024] In other words, the maximum nitrogen consumption flow rate that may occur simultaneously among the sub-users in the user group is the tripping threshold of the excess flow valve corresponding to the user group.

[0025] Table 1

[0026]

[0027]

[0028]

[0029] SCD032 User Group: Among the sub-users included in this user group (e.g., all extruder screw conveyors, peroxide discharge tanks, additive discharge stations, etc.), some (e.g., those not marked with an *) utilize continuous nitrogen flow as shown in Table 2 and should all be included in the flow calculation. Meanwhile, another portion (e.g., those marked with an *) utilizes discontinuous nitrogen flow. For example, if up to three sub-users (e.g., discharge stations) operate simultaneously, only the three discontinuous flow sub-users will be included in the calculation. The resulting total is the predetermined flow threshold for the excess flow valve for this user group. Similarly, the maximum possible simultaneous nitrogen consumption by the sub-users in this user group serves as the tripping threshold for the excess flow valve for this user group.

[0030] Table 2

[0031]

[0032]

[0033] SCD033 User Group: Of the sub-users included in this user group (e.g., all additive system rotary valves), only three sub-users (e.g., rotary valves) can operate simultaneously. Therefore, only the required flow rates of three of these sub-users from Table 3 need to be included in the calculation, and a multiplication factor of 1.1 can be applied to the total. In other words, the maximum possible nitrogen consumption flow rate of the sub-users in this user group, multiplied by an appropriate multiplication factor, will determine the tripping threshold for the excess flow valve for this user group.

[0034] Table 3

[0035]

[0036]

[0037] SCD034 User Group: All sub-users within this user group utilize continuous nitrogen flow. Therefore, when determining the predetermined flow threshold for the overflow valve, all users listed in Table 4 must be included in the calculation, and a multiplication factor of 1.3 may be applied to the total amount. Similarly, the maximum simultaneous nitrogen consumption rate of the sub-users within this user group, multiplied by an appropriate multiplication factor, will determine the tripping threshold for the overflow valve for this user group.

[0038] Table 4

[0039]

[0040] As can be seen above, the predetermined flow threshold of the excess flow valve 5 installed on each main supply line 3 is selected to be equal to (for example, corresponding to SCD031-SCD032) or slightly greater than (for example, for SCD033, which has a multiplication factor of 1.1, and for SCD034, which has a multiplication factor of 1.3, or other suitable multiplication factors, such as between 1.1 and 1.3) the maximum nitrogen consumption flow rate of all nitrogen users connected to the corresponding main supply line 3 during the same time period. Thus, by installing such an excess flow valve 5 and setting the predetermined flow threshold of the excess flow valve 5 in the above manner, it is possible to determine whether a nitrogen user has a leak based on the open or closed state of the excess flow valve 5, and to prevent safety risks caused by nitrogen leaks by blocking the excess flow valve.

[0041] Next, we will combine Figure 2 The specific structure of the excess flow valve 5 discussed above is explained.

[0042] like Figure 2As shown, the excess flow valve 5 includes a valve housing 51, a valve body 52 disposed within the valve housing 51, and a spring assembly 53. The valve housing 51 is provided with an inlet 511 for communication with the nitrogen supply source 2, an outlet 512 for communication with the downstream nitrogen user group 4, and a valve seat 513 disposed within the valve housing 51 near the outlet 512. The valve seat 513 is formed as an annular seat within the valve housing 51. The valve body 52 includes a valve stem 521 and a valve disc 522, typically formed integrally. A guide sleeve 54 is also connected to the valve housing 51. The valve stem 521 of the valve body 52 passes through the guide sleeve 54 so as to be able to slide relative to the guide sleeve 54. The guide sleeve 54 provides guidance for the movement of the valve stem 521. A first spring seat 532 is provided on the side of the valve stem 521 near the guide sleeve 54, and a second spring seat 533 is provided near the free end of the valve stem 521. The spring assembly 53 includes a spring 531 arranged around the valve stem 521 and constrained between a first spring seat 532 and a second spring seat 533. In order to limit any undesired axial movement of the guide sleeve 54 and the second spring seat 533, a first locking nut 55 and a second locking nut 56 are provided respectively.

[0043] During operation of the nitrogen supply system 1, the valve body 52 can remain open when the pressure between the inlet and outlet sides is balanced. However, when an abnormal pressure drop greater than a predetermined value occurs between the inlet and outlet sides, the valve body 52 is urged by the spring assembly 53 to cause the valve disc 522 of the valve body 52 to abut against the valve seat 513, thereby closing the outlet 512. Because changes in the pressure drop are directly related to changes in the flow rate or flow velocity of nitrogen passing through the excess flow valve 5, the predetermined value used to determine whether an abnormal pressure drop exists is associated with the predetermined flow threshold of the excess flow valve described above.

[0044] Still see Figure 2 A pressure balancing port 5221 is also provided on the valve disc 522. The pressure balancing port 5221 can balance the pressures on the inlet and outlet sides of the excess flow valve when the flow rate of nitrogen flowing through the excess flow valve is restored to a value not exceeding a predetermined flow threshold, thereby returning the excess flow valve to an open state to resume supplying nitrogen to the downstream nitrogen users.

[0045] Next, see Figure 3 A method for supplying nitrogen using the nitrogen supply system according to the present invention is described. The method may mainly include the following steps:

[0046] Supplying nitrogen from a nitrogen supply source through a corresponding supply main line and through an open overflow valve to a nitrogen user group located in a closed factory building;

[0047] In the case where the flow rate of nitrogen flowing through the excess flow valve does not exceed a predetermined flow threshold, the excess flow valve is continuously kept in an open state so that nitrogen can be supplied to various nitrogen users along various supply main lines; and

[0048] When the flow rate of nitrogen flowing through the excess flow valve exceeds a predetermined flow threshold, the excess flow valve automatically switches from an open state to a closed state to cut off the supply of nitrogen from the nitrogen supply source to each nitrogen user.

[0049] Advantageously, when the flow rate of nitrogen flowing through the excess flow valve is restored to not more than a predetermined flow rate threshold, the excess flow valve automatically returns from the closed state to the open state.

[0050] In this way, by installing an excess flow valve to prevent excessive nitrogen on the main nitrogen supply line, the excess flow valve can be actively cut off and kept closed when the nitrogen flow flowing through the excess flow valve exceeds a predetermined flow threshold, thereby preventing a large amount of nitrogen from leaking into the closed factory building and causing a risk of suffocation. After the leakage risk is eliminated, the excess flow valve can still be reopened to restore the normal supply of nitrogen.

[0051] It should be noted that the embodiments described above are intended to be exemplary only, and the present invention is not limited to these embodiments. By considering the contents of this specification, those skilled in the art may make various changes and modifications without departing from the scope or spirit of the present invention. The true scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A nitrogen supply system, comprising: a nitrogen supply source (2); a plurality of supply main lines (3) in fluid communication with the nitrogen supply source; and an excess flow valve (5) disposed in each of the supply main lines; each of the supply main lines being connected to a corresponding nitrogen user group (4) located in a sealed factory building (6); the nitrogen user group comprising a plurality of nitrogen users; It is characterized by: The excess flow valve is located outside the sealed plant (6), and is configured such that: when the flow rate of nitrogen flowing through the excess flow valve (5) does not exceed a predetermined flow rate threshold of the excess flow valve, the excess flow valve remains in an open state so that nitrogen can be supplied to various nitrogen users along various supply main lines (3); and when the flow rate of nitrogen flowing through the excess flow valve (5) exceeds the predetermined flow rate threshold, the excess flow valve (5) automatically switches to a closed state.

2. The nitrogen supply system according to claim 1, characterized in that The predetermined flow rate threshold is selected to be equal to the maximum nitrogen consumption flow rate of all nitrogen users in the nitrogen user group (4) connected to the corresponding supply main line (3) within a same period.

3. The nitrogen supply system according to claim 1, characterized in that The predetermined flow rate threshold is selected to be greater than the maximum nitrogen consumption flow rate of all nitrogen users in the nitrogen user group (4) connected to the corresponding supply main line (3) within the same period.

4. The nitrogen supply system according to claim 3, characterized in that: The predetermined flow rate threshold is selected to be equal to 1.1-1.3 times the maximum nitrogen consumption flow rate in the same period.

5. The nitrogen supply system according to any one of claims 1 to 4, characterized in that: The excess flow valve (5) comprises a valve housing (51), a valve body (52) and a spring assembly (53) arranged in the valve housing (51); wherein the valve housing (51) is provided with an inlet (511) intended to be in fluid communication with the nitrogen supply source, an outlet (512) intended to be in fluid communication with a downstream nitrogen user group, and a valve seat (513) arranged in the valve housing (51) near the outlet (512); the valve body (52) comprises a valve stem (521) and a valve disc (522); and the spring assembly (53) comprises a spring (531) arranged around the valve stem (521); The excess flow valve (5) is capable of remaining open when the pressure between the inlet side and the outlet side is balanced, and when an abnormal pressure drop greater than a predetermined value exists between the inlet side and the outlet side, the valve body (52) of the excess flow valve is driven by the spring assembly (53) so that the valve disc (522) of the valve body abuts against the valve seat (513) to close the outlet, and the predetermined value is associated with the predetermined flow threshold of the excess flow valve.

6. The nitrogen supply system according to claim 5, characterized in that: The valve disc (522) is provided with a pressure balancing port (5221), which can balance the pressures on the inlet and outlet sides of the excess flow valve when the flow rate of nitrogen flowing through the excess flow valve is restored to a value not exceeding a predetermined flow threshold, thereby returning the excess flow valve to an open state.

7. The nitrogen supply system according to claim 5, characterized in that: The abnormal pressure drop indicates that one or more leakage points exist at the nitrogen user group located in the closed plant or at the section of the main supply line located in the closed plant.

Images