A normally open solenoid valve

Abstract

The present invention provides a normally open solenoid valve, comprising an outer sleeve A, a static iron core A, a moving iron core A, an electromagnetic coil A, a valve core and an upper fixed component, wherein the valve core comprises a push rod, a sealing column and an outer spring. When the solenoid valve is in a charged state, the moving iron core A moves so that the sealing column overcomes the elastic force of the outer spring to complete the sealing of the measuring gas docking outlet, thereby completing the instantaneous closure of the normally open solenoid valve. During the closing process of the normally open solenoid valve, the gas pressure difference between the upper and lower parts of the sealing column is utilized to ensure that the normally open solenoid valve completely isolates and seals the gas at the measuring gas docking outlet, and the existence of this pressure difference can also ensure that the instantaneous closure of the normally open solenoid valve becomes more reliable and rapid. When the solenoid valve is powered off, the elastic force of the outer spring ensures that the solenoid valve opens instantaneously.

Description

[0001] This application is a divisional application of the Chinese invention patent entitled "A back-purge device for measuring gas pipelines", application number 202010375235.4, and application date May 7, 2020. Technical Field

[0002] The invention belongs to the technical field of gas control and relates to a back-purge device, in particular to a back-purge device for measuring a gas pipeline. Background Art

[0003] Air volume / pressure measurement is a very important monitoring indicator in industrial boilers, such as thermal power plants, metallurgy, coal chemical industry, etc. Even if the air volume / pressure measuring device is based on the differential pressure air volume monitoring principle and the air volume transmitter / constant pressure air pressure monitoring principle, it will not work normally for a long time in a dusty environment if there is a lack of traceless anti-blocking purge. The main reasons for the blockage of air volume / pressure measuring devices are: 1) The pressure change in the pressure lead line (measuring gas line) of the measuring device causes blockage; 2) The air tightness of the pressure lead line (measuring gas line) of the measuring device is poor, resulting in large-scale blockage at the leakage point from the transmitter to the pressure lead line.

[0004] However, the existing anti-blocking measures are limited to preventing blockage and cannot completely solve the blockage problem in the air volume / air pressure measuring device. The existing anti-blocking measures are:

[0005] 1) Send workers to purge with purge gas regularly: This measure not only wastes manpower, but also affects the fluctuation of the transmitter and affects safe production.

[0006] 2) Install an anti-clogging wind pressure sampler on the measuring gas pipeline (using the principle of fluid mechanics, a wind pressure compensator is added to the system, the zero point value, full scale value and linear value are mathematically derived, and the non-clogging area, non-burning area and compensator are linearized): After long-term operation of this measure, fine powder still accumulates and causes clogging of the device.

[0007] 3) A constant-flow micro-positive-pressure purge device installed on the measuring gas pipeline: This constant-flow micro-positive-pressure purge device has a weak purge force and can only delay the blockage of the device but cannot fundamentally solve the problem. Summary of the Invention

[0008] In order to solve the above-mentioned technical problems, the present invention provides a back-purge device that can measure the measurement gas normally without interference regardless of whether it is in a normal measurement state or a purge measurement state, comprising:

[0009] The valve island includes a valve island body and a purge gas pipeline and a measuring gas pipeline therein. The purge gas pressure at the inlet of the purge gas pipeline is 1 MPa or less, and the measuring gas pressure at the inlet of the measuring gas pipeline is 8 kPa or less.

[0010] A measuring gas air volume / pressure transmitter is installed at the outlet of the measuring gas pipeline, and measures the air volume / pressure of the measuring gas flowing into the measuring gas pipeline inlet in real time under both the normal measurement state and the purge measurement state of the device;

[0011] A normally open solenoid valve is installed on the valve island body and is used to control the flow of gas in the measuring gas pipeline. When the device is energized in the purge measurement state, the measuring gas pipeline is disconnected and the purge gas is isolated from the measuring gas in the measuring gas pipeline connected to the measuring gas volume / pressure transmitter. When the device is energized, the normally open solenoid valve is instantly closed.

[0012] A normally closed solenoid valve, mounted on the valve island body, is used to control the on / off setting of the purge gas pipeline. When the device is not powered in normal measurement mode, the purge gas pipeline is disconnected and the purge gas is isolated from the measuring gas in the measuring gas pipeline. When powered on, the normally closed solenoid valve opens instantaneously; and

[0013] The device controller is used to control the purge measurement state and normal measurement state of the device, and is connected to the normally open solenoid valve, normally closed solenoid valve, measuring gas air volume / air pressure transmitter, and blockage monitoring pressure gauge through cables.

[0014] The above-mentioned back-purge device also includes a blockage monitoring pressure gauge, which is installed on the measuring gas pipeline connected to the measuring gas air volume / air pressure transmitter, and is used to monitor in real time whether the measuring gas pipeline connected to the measuring gas pipeline inlet is blocked, and output a blockage signal to the device controller.

[0015] The purge gas pressure at the purge gas pipeline inlet is 0.6 MPa or less, and the measurement gas pressure at the measurement gas pipeline inlet is 6 KPa or less.

[0016] The valve island body is further provided with a circular groove for measuring gas and a circular groove for purge gas; the measuring gas pipeline further comprises a measuring gas inlet pipeline and a measuring gas docking inlet connected to its two ends respectively, a measuring gas outlet pipeline and a measuring gas docking outlet connected to its two ends respectively, the measuring gas circular groove is provided on one side of the valve island body, the measuring gas docking outlet is an annular protrusion provided at the center of the measuring gas circular groove, the measuring gas docking inlet is provided in the measuring gas circular groove and is a flat opening staggered from the measuring gas docking outlet, and the diameter of the measuring gas docking inlet is larger than the diameter of the measuring gas docking outlet; the purge gas pipeline further comprises a purge gas inlet pipeline and a purge gas docking inlet connected to its two ends respectively, a purge gas outlet pipeline connected to the measuring gas inlet pipeline and its purge gas docking outlet, the purge gas circular groove is provided on one side of the valve island body, the purge gas docking outlet is an annular protrusion provided at the center of the purge gas circular groove, the purge gas docking inlet is provided in the purge gas circular groove and is a flat opening staggered from the purge gas docking outlet, and the diameter of the purge gas docking inlet is smaller than the purge gas docking outlet.

[0017] The normally open solenoid valve mentioned above comprises:

[0018] The outer sleeve A is provided on the circular groove of the measuring gas of the valve island body to seal the valve from the outside, and includes the outer sleeve A body, an upper end with an externally threaded boss, and a lower end with an outer peripheral edge; the outer sleeve A body is made of non-magnetic metal material;

[0019] The static iron core A is used to generate electromagnetic force, including a static iron core A body and a central fine through hole, and a lower end of the central fine through hole of the static iron core A body is provided with a lower groove;

[0020] A valve core, used to open and close the gas between the measuring gas docking outlet and the measuring gas docking inlet in the circular groove for measuring gas, comprising a push rod, a sealing cylinder, and an external spring; wherein the sealing cylinder is placed in the groove below the main body of the static iron core A, the push rod is placed in the central fine through hole of the main body of the static iron core A, and the external spring is arranged between the sealing cylinder and the measuring gas docking outlet;

[0021] The moving iron core A is used to transmit the electromagnetic force generated by the static iron core A to the valve core, thereby generating a downward mechanical thrust on the valve core. The moving iron core A is placed on the upper side of the static iron core A body within the outer sleeve A body.

[0022] The electromagnetic coil A is used to generate electromagnetic force in the static iron core A to attract the moving iron core A. The electromagnetic coil A comprises a coil A, a frame A, a retaining ring A, and a housing A. The coil A is wound around the frame A, embedded in the housing A, and fixed by the retaining ring A.

[0023] A lower fixing component, which fixes the outer sleeve A body to the measuring gas circular groove of the valve island body by utilizing the outer periphery of the lower port of the outer sleeve A body; and

[0024] The upper fixing component is used to fix the electromagnetic coil A up and down outside the outer sleeve A body.

[0025] The above-mentioned sealing column includes a cylindrical shell with a lower opening and its side wall hole, an inner spring embedded in the lower opening of the cylindrical shell in sequence, and an inverted convex sealing plug with a boss on the lower end face. The elastic force of the inner spring is greater than the elastic force of the outer spring.

[0026] The above-mentioned lower fixing component includes a hollow lower module, a hollow upper module, an inner O-ring, an outer O-ring and a screw A; wherein the hollow lower module is fixed to the circular groove of the measuring gas of the valve island body by screw A, the hollow upper module is threadedly screwed into the hollow lower module and the outer sleeve A body and the valve island body are fixed together through the outer periphery of the lower port of the outer sleeve A body, and the inner O-ring is arranged between the outer periphery of the lower port of the outer sleeve A body and the hollow lower module, and the outer O-ring is arranged in the annular groove provided at the contact surface between the hollow lower module and the valve island body.

[0027] The upper fixing component is a fixing screw cap, which is screwed onto the boss at the upper end of the outer sleeve A body to fix the electromagnetic coil A up and down.

[0028] The non-magnetic metal material mentioned above is stainless steel, copper or aviation aluminum.

[0029] The normally closed solenoid valve comprises:

[0030] The outer sleeve B is provided on the circular purge gas groove of the valve island body to seal to the outside, and includes an outer sleeve B body with an outer edge at the bottom end, an annular magnetic conductive groove, screws B and a lower O-ring; wherein the outer edge of the bottom end of the outer sleeve B body is used to be fixed to the valve island body by screws B, and an annular groove is provided on its bottom surface for inserting the lower O-ring; the annular magnetic conductive groove is provided on the outer side surface of the upper end of the outer sleeve B body; the outer sleeve B body is made of non-magnetic metal material;

[0031] The static iron core B is used to generate electromagnetic force and is inserted into the outer sleeve B body through interference fit;

[0032] The moving iron core B generates an upward electromagnetic attraction on the static iron core B, so that the purge gas docking outlet and the purge gas docking inlet are connected to each other by gas; the axially movable moving iron core B is embedded in the outer sleeve B body and is installed on the lower side of the static iron core B in the outer sleeve B body; it includes the moving iron core B body and its ventilation side grooves, transverse air holes, and upward grooves; wherein the upward groove is provided at the center of the upper end surface of the moving iron core B body, the ventilation side grooves are provided on the side surface of the moving iron core B body, and the upward groove is connected to the ventilation side grooves through the transverse air holes;

[0033] A return spring is used to return the movable iron core B body to the outer sleeve B body, thereby disconnecting the gas between the purge gas docking outlet and the purge gas docking inlet; one end of the return spring is inserted into the upward groove of the movable iron core B body, and the other end is pressed against the lower end surface of the static iron core B;

[0034] The electromagnetic coil B is used to make the static iron core B generate magnetic force to attract the moving iron core B, and includes a coil B, a frame B, a retaining ring B and a shell B. The coil B is wound around the frame B, embedded in the shell B and fixed by the retaining ring B. The electromagnetic coil B is sleeved outside the outer sleeve B body; and

[0035] The upper end nut is screwed onto the upper end of the outer sleeve B body through threads to fix the electromagnetic coil B up and down outside the outer sleeve B body.

[0036] The lower end surface of the movable iron core B body is further provided with a downward groove and a sealing gasket embedded therein.

[0037] The non-magnetic metal material mentioned above is stainless steel, copper or aviation aluminum.

[0038] The present invention provides a back-purge device for a measuring gas pipeline, which mainly adopts a normally open solenoid valve with a measuring gas docking inlet diameter larger than its measuring gas docking outlet diameter, and a normally closed solenoid valve with a small diameter design for the purge gas inlet pipeline and a large diameter design for the purge gas outlet pipeline. At the same time, it cleverly utilizes the fact that the purge gas pressure (1MPa and below) is much greater than the measuring gas pressure (8KPa and below); whether in a normal measuring state, the strong pressure of the purge gas in the purge gas inlet pipeline enables the normally closed solenoid valve to reliably isolate and seal the measuring gas in the measuring gas pipeline, or in a purge measurement state, the strong pressure of the purge gas entering the measuring gas inlet pipeline enables the normally open solenoid valve to reliably isolate and seal the measuring gas in the measuring gas outlet pipeline, and it can also ensure that the normally closed solenoid valve opens instantaneously, ensuring that the gas measurement operation of the device is safe and reliable in both the normal measurement state and the purge measurement state. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1A schematic diagram of a back-purge device system for measuring gas pipelines provided by the present invention.

[0040] Figure 2 for Figure 1 Schematic diagram of the normally open solenoid valve structure in the system shown.

[0041] Figure 3 for Figure 1 Schematic diagram of the normally closed solenoid valve structure in the system shown.

[0042] Figure 4 for Figure 1 Main view of the valve island in the system shown.

[0043] Figure 5 for Figure 1 Rear view of the valve terminal in the system shown.

[0044] Figure 6 for Figure 1 Top view of the valve terminal in the system shown.

[0045] Figure 7 for Figure 6 Cross-sectional view of AA in the figure.

[0046] Figure 8 for Figure 6 Cross-sectional view of the BB.

[0047] Figure 9 for Figure 6 Cross-sectional view of CC.

[0048] Figure 10 for Figure 6 Cross-sectional view of DD.

[0049] Figure 11 for Figure 4 Cross-sectional view of EE. DETAILED DESCRIPTION

[0050] A back-purge device for measuring a gas pipeline provided by the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] like Figure 1 , which is a schematic diagram of a back-purge device system for measuring gas pipelines provided by the present invention, including a valve island 100, a normally open solenoid valve 300, a normally closed solenoid valve 200, a measuring gas air volume / air pressure transmitter 400, a blockage monitoring pressure gauge (not shown in the figure) and a device controller (not shown in the figure).

[0052] The structure of the valve island 100 is as follows:

[0053] like Figure 1 and Figure 4-10The valve island 100 includes a valve island body 100A and is provided with a purge gas pipeline, a measuring gas pipeline, a measuring gas circular groove 111 and a purge gas circular groove 108;

[0054] The measuring gas pipeline includes a measuring gas inlet pipeline (including 103 and 105) and a measuring gas docking inlet connected to each end thereof, a measuring gas pipeline inlet connected to the measured gas pipeline, a measuring gas outlet pipeline (including 104 and 102) and a measuring gas docking outlet connected to each end thereof, and a measuring gas pipeline outlet for installing the measuring gas air volume / air pressure transmitter 400. The measuring gas circular groove 111 is provided on one side of the valve island body 100A. The measuring gas docking outlet is an annular protrusion provided at the center of the measuring gas circular groove 111. The measuring gas docking inlet is provided in the measuring gas circular groove 111 and is a flat opening staggered from the measuring gas docking outlet.

[0055] The purge gas pipeline includes a purge gas inlet pipeline (including 101, 114 and 107) and purge gas docking inlets connected to its two ends respectively and a purge gas pipeline inlet connected to the purge gas, a purge gas outlet pipeline (including 106 and 117) connected to the measuring gas inlet pipeline 103 section and its purge gas docking outlet, the purge gas circular groove 108 is provided on one side surface of the valve island body 100A, the purge gas docking outlet is an annular protrusion provided in the center of the purge gas circular groove 108, and the purge gas docking inlet is provided in the purge gas circular groove 108 and is a flat opening staggered from the purge gas docking outlet.

[0056] In order to increase the purge gas intake volume and improve the purge effect on the measuring gas inlet pipeline during the purge measurement state: the purge gas inlet pipeline section 101 is designed as a three-stage pipeline structure with gradually reduced diameters from the outside to the inside, and the diameter of the innermost first-stage pipeline section is the same as the diameter of the purge gas inlet pipeline section 114; the measuring gas inlet pipeline section 103 is designed as a two-stage pipeline structure with gradually reduced diameters from the outside to the inside, and the measuring gas inlet pipeline section 105 is vertically close to the inner side wall of the purge gas outlet pipeline section 117 and communicates with the inner end of the smaller diameter pipeline section of the measuring gas inlet pipeline section 103; The measuring gas outlet pipeline section 102 is designed as a two-stage structure with gradually decreasing diameters from the outside to the inside. The measuring gas outlet pipeline section 104 is perpendicularly connected to the inner end of the smaller static pipe of the measuring gas outlet pipeline section 102. Furthermore, the diameters of these pipeline sections are designed so that the smaller diameter of the measuring gas inlet pipeline section 103 within the valve island body is larger than the diameter of the purge gas inlet pipeline section 107 and equal to the smallest diameter of the purge gas inlet pipeline section 101; alternatively, the smaller diameter of the measuring gas inlet pipeline section 103 within the valve island body is equal to the smallest diameter of the purge gas inlet pipeline section 101. This allows purge gas to flow from the purge gas inlet within the valve island body to the measuring gas inlet without being throttled. When released from the measuring gas inlet at a pressure of 1 MPa or less, the purge gas expands by 200-1400 times, significantly improving the purge gas's cleaning effect on the measuring gas inlet pipeline.

[0057] The structure of the normally open solenoid valve:

[0058] like Figure 2 This is a structural diagram of a normally open solenoid valve 300, which is installed on the measuring gas circular groove of the valve island body and is used to control the flow of gas between the measuring gas docking outlet and the measuring gas docking inlet in the measuring gas circular groove. It includes an outer sleeve A, a static iron core A, a movable iron core A 311, an electromagnetic coil A, a valve core, a lower fixing component, and an upper fixing component.

[0059] The outer sleeve A is provided on the circular groove of the valve island body for measuring gas to seal the valve island body, and includes an outer sleeve A body 310, an upper end with an externally threaded boss, and a lower end with an outer peripheral edge; the outer sleeve A body 310 is made of a non-magnetic metal material, such as stainless steel, copper, or aviation aluminum;

[0060] The static iron core A is used to generate electromagnetic force, and includes a static iron core A body 313 and a central fine through hole thereof, and a lower end of the central fine through hole of the static iron core A body is provided with a lower groove;

[0061] The valve core is used to open and close the gas between the measuring gas docking outlet and the measuring gas docking inlet in the circular groove for measuring gas, and includes a push rod 312, a sealing cylinder and an external spring 318, wherein the sealing cylinder is placed in the groove below the main body of the static iron core A, the push rod is placed in the fine through hole in the center of the main body of the static iron core A, and the external spring is arranged between the sealing cylinder and the measuring gas docking outlet; in order to achieve a better sealing effect of closing the measuring gas docking outlet, the sealing cylinder structure is designed as follows: a cylindrical shell 314 with a lower opening and its side wall hole 317, an inner spring 315 embedded in sequence from its lower end port, and an inverted convex sealing plug 316 with a boss on the lower end surface; the side wall hole 317 is used as a vent when the inner spring recovers, and the elastic force of the inner spring is greater than that of the outer spring;

[0062] The movable iron core A 311 is used to transmit the electromagnetic force generated by the static iron core A to the valve core, thereby generating a downward mechanical thrust on the valve core; it is placed on the upper side of the static iron core A body within the outer sleeve A body;

[0063] The electromagnetic coil A is used to generate electromagnetic force in the static iron core A to attract the moving iron core A. It includes a coil A303, a frame A302, a retaining ring A304, and a shell A301. The coil A is wound around the frame A, embedded in the shell A, and fixed by the retaining ring A.

[0064] The lower fixing component uses the outer peripheral edge of the lower port of the outer sleeve A body to fix the outer sleeve A body on the measuring gas circular groove of the valve island body 100A; it includes a hollow lower module 306, a hollow upper module 307, an inner O-ring 308, an outer O-ring 309 and a screw A 305; wherein the hollow lower module 306 is fixed to the measuring gas circular groove of the valve island body 100A by the screw A 305, the hollow upper module 307 is threadedly tightened in the hollow lower module 306 and fixes the outer sleeve A body and the valve island body 100A together through the outer peripheral edge of the lower port of the outer sleeve A body, and the inner O-ring 308 is arranged between the outer peripheral edge of the lower port of the outer sleeve A body and the hollow lower module 306, and the outer O-ring 309 is arranged in the annular groove provided at the contact surface between the hollow lower module 306 and the valve island body 100A.

[0065] The upper fixing component is used to fix the electromagnetic coil A up and down outside the outer sleeve A body, and is a fixing screw nut 360, which is screwed onto the boss at the upper end of the outer sleeve A body 310 to fix the electromagnetic coil A up and down.

[0066] The structure of the normally closed solenoid valve:

[0067] like Figure 3This is a structural diagram of a normally closed solenoid valve 200, which is installed on the purge gas circular groove of the valve island body and is used to control the flow of gas between the purge gas docking outlet and the purge gas docking inlet in the purge gas circular groove. It includes an outer sleeve B, a static iron core B 220, a moving iron core B, a return spring 230, an electromagnetic coil B and an upper end nut 260.

[0068] The outer sleeve B is provided with a circular purge gas groove on the valve island body for external sealing, and includes an outer sleeve B body 210 with an outer edge at the bottom end, an annular magnetic conductive groove 211, screws B 212, and a lower O-ring 213; wherein the outer edge of the bottom end of the outer sleeve B body 210 is fixed to the valve island body 100A by screws B, and an annular groove is provided on its bottom surface for embedding the lower O-ring 213; the annular magnetic conductive groove 211 is provided on the outer side surface of the upper end of the outer sleeve B body 210; the outer sleeve B body 210 is made of a non-magnetic metal material, such as stainless steel, copper, or aviation aluminum;

[0069] The static iron core B 220 is used to generate electromagnetic force on the moving iron core B and is inserted into the outer sleeve B body 210 by interference fit;

[0070] The moving iron core B generates an upward electromagnetic force on the static iron core B 220, so that the purge gas docking outlet and the purge gas docking inlet are connected by gas. The axially movable moving iron core B is arranged in the outer sleeve B body 210 and is installed on the lower side of the static iron core B 220 in the outer sleeve B body 210; it includes a moving iron core B body 240 and its ventilation side groove 242, a transverse air hole 241, and an upward groove; wherein the upward groove is arranged at the center of the upper end surface of the moving iron core B body 240, the ventilation side groove 242 is arranged on the side surface of the moving iron core B body 240, and the upward groove is connected with the ventilation side groove 242 through the transverse air hole 241; in order to better seal the purge gas docking outlet in the non-energized state, a downward groove is further provided at the center of the lower end surface of the moving iron core B body 240, and a sealing gasket 250 is embedded therein;

[0071] The return spring 230 is used to return the movable iron core B body to its original position within the outer sleeve B body 210, thereby disconnecting the gas flow between the purge gas docking outlet and the purge gas docking inlet. One end of the return spring 230 is inserted into the upward groove of the movable iron core B body 240, and the other end presses against the lower end surface of the stationary iron core B 220.

[0072] The electromagnetic coil B is used to make the static iron core B generate magnetic force to attract the moving iron core B body, including a coil B 203, a skeleton B 202, a retaining ring B 204 and a shell B 201. The coil B is wound in the skeleton B, embedded in the shell B and fixed by the retaining ring B; the electromagnetic coil B is sleeved on the outside of the outer sleeve B body 210, and is screwed on the upper end of the outer sleeve B body by the upper end nut 260, so that the electromagnetic coil B is fixed up and down on the outside of the outer sleeve B body 210.

[0073] like Figures 1 to 11 The working principle of the above-mentioned back-purge device for measuring gas pipelines is as follows:

[0074] The measuring gas pipeline inlet of the valve island body is connected to the measured gas (its air pressure is 8KPa and below), the measuring gas pipeline outlet of the valve island body is connected to the air volume / air pressure transmitter, the purge gas pipeline inlet of the valve island body is connected to the purge gas (its air pressure is 1MPa and below), the normally open solenoid valve is installed on the measuring gas circular groove of the valve island body, the normally closed solenoid valve is installed on the purge gas circular groove of the valve island body, the blockage monitoring pressure gauge is installed on the measuring gas outlet pipeline of the valve island body, and the device controller is connected to the normally open solenoid valve, the normally closed solenoid valve and the blockage monitoring pressure gauge through cables respectively.

[0075] 1) When the device is in normal measurement state, that is, when the blockage monitoring pressure gauge installed on the measuring gas output pipeline monitors the measuring gas inlet pipeline and there is no blockage, the device controller controls the normally open solenoid valve and the normally closed solenoid valve to not operate (that is, no power is applied to either valve):

[0076] The elastic force of the outer spring 318 in the normally open solenoid valve overcomes the inherent weight of the sealing cylinder, movable iron core A 311, and ejector pin 312, opening the measurement gas connection outlet. This allows for communication between measurement gas outlet pipeline section 104 and measurement gas inlet pipeline section 105. Simultaneously, the purge gas in the normally closed solenoid valve flows sequentially through the purge gas inlet pipeline 107, the vent side groove 242, the transverse air hole 241, and the upward groove to the space formed between the stationary iron core B 220 and the movable iron core B. The purge gas connection outlet is then sealed by the return spring 230 and the purge gas against the movable iron core B through the sealing gasket 250. When the normally closed solenoid valve is not actuated, the forces acting on the movable core B are: the downward force F1 of the return spring, the weight F2 of the movable core B itself, the downward pressure F3 (approximately 1 MPa and below) created by the purge gas entering the solenoid valve, and the upward pressure F4 (8 kPa and below) of the measuring gas in the purge gas outlet pipeline. This ensures that even when there is no or very low pressure measuring gas, the purge gas will not flow into the purge gas outlet pipeline and interfere with the transmitter's normal measurement of the gas volume / pressure. In this way, the measuring gas flows sequentially from the measuring gas pipeline inlet, measuring gas inlet pipeline, measuring gas docking inlet, measuring gas docking outlet, measuring gas outlet pipeline, and measuring gas pipeline outlet to the air volume / pressure transmitter, providing real-time monitoring of the measured gas pipeline's air volume / pressure.

[0077] 2) When the device is in the purge measurement state, that is, when the blockage monitoring pressure gauge detects that the measuring gas inlet pipeline is blocked or at the predetermined purge moment or time:

[0078] The device controller first energizes the normally open solenoid valve, and the static iron core A generates an electromagnetic force to move the moving iron core A311 downward, and uses the sealing cylinder to deform the outer spring 318 through the push rod 312, so that the inverted convex sealing plug 316 instantly seals the measuring gas docking outlet, so that the measuring gas between the measuring gas outlet pipeline 104 and the measuring gas inlet pipeline 105 is disconnected (the sealing cylinder is provided with an inner spring 315 and an inverted convex sealing plug 316, in order to ensure that the sealing cylinder seals the measuring gas docking outlet reliably, due to the presence of measuring gas in the measuring gas outlet pipeline 104, its pressure will cause the inverted convex sealing plug 316 to deform upward and make it better sealed). At this time, the measuring gas inlet pipeline is connected to the purge gas outlet pipeline; then the device controller immediately energizes the normally closed solenoid valve, and the static iron core B 220 generates electromagnetic force to move the moving iron core B body 240 upward, and the purge gas inlet pipeline and the purge gas outlet pipeline are connected. The MPa-level purge gas and the KPa-level air pressure sealed in the measuring gas outlet pipeline act on the sealing column of the normally open solenoid valve up and down. On the basis of the electromagnetic force of the electromagnetic coil A, a large pressure difference is formed (even if there is an upward elastic force of an external spring 318), which can ensure that no purge gas is injected into the measuring gas outlet pipeline, so that the air volume / pressure transmitter can work safely and without interference even in the purge state of the device. At the same time, the purge gas flows through the purge gas outlet pipeline to the measuring gas inlet pipeline for back-purge. As the purge gas flows through the purge gas line to the measuring gas inlet line, the MPa-grade purge gas instantly expands 200-1400 times its original volume at the measuring gas inlet, instantly purging any deposits within the measuring gas inlet line. The device controller then de-energizes the normally closed solenoid valve, disconnecting the purge gas line and halting the purge. The device controller then de-energizes the normally open solenoid valve, restoring the measuring gas line to its normal measurement state. The air volume / pressure transmitter continues to monitor the measuring gas in the measuring gas line in real time. In the purge measurement state, the air volume / pressure transmitter maintains the air volume / pressure parameters prior to the purge without interference from the purge gas.

[0079] When the gas pipeline is measured during gas volume / pressure monitoring for a long time, dust may easily accumulate at the inlet of the measuring gas pipeline and the measuring gas inlet pipeline, causing blockage. This will lead to inaccurate monitoring of the measured gas volume / pressure or even loss of measurement. If the above-mentioned blockage occurs, the controller controls the normally open solenoid valve and the normally closed solenoid valve to work with power, and the normally open solenoid valve is closed during the purge process to isolate the air volume / pressure transmitter connected to the measuring gas outlet pipeline from the purge gas. This not only ensures that the purge gas back-blows the measuring gas inlet pipeline through the gas purge pipeline, but also avoids interference of the purge gas on the air volume / pressure transmitter, thereby ensuring that the air volume / pressure transmitter can monitor the air volume / pressure of the measured gas pipeline in real time and accurately.

[0080] During the purge process, the normally open solenoid valve is ensured to be closed instantly and better mainly by utilizing the electromagnetic force of the normally open solenoid valve, and based on the structural design that the diameter of the measuring gas docking inlet is larger than the diameter of the measuring gas docking outlet, the purge gas (1MPa and below) is used to generate a pressure on the valve core that is much greater than the measuring gas pressure (8KPa and below) in the sealing measuring gas outlet pipeline, so that the normally open solenoid valve can greatly enhance the effect of isolating the sealing purge gas; when the normally closed solenoid valve is powered on and opened under the action of the purge gas pressure of 1MPa and below in the purge gas inlet pipeline, it can be opened instantly and better by relying on the electromagnetic force of the normally closed solenoid valve itself. The purge gas outlet pipeline is designed to have a large diameter, and the purge gas inlet pipeline is Designed with a smaller diameter, this not only effectively isolates the purge gas outlet from the purge gas inlet during normal measurement, ensuring safe operation of the measuring instrument, but also facilitates the opening of the normally closed solenoid valve. This allows for both normal measurement, where the strong pressure of the purge gas in the purge gas inlet ensures the normally closed solenoid valve isolates and seals the measuring gas in the pipe, and purge measurement, where the strong pressure of the purge gas entering the pipe ensures the normally open solenoid valve isolates and seals the measuring gas in the pipe. This ensures safe and reliable gas measurement in both normal and purge measurement states.

Claims

1. A normally open solenoid valve, characterized in that: It includes an outer sleeve A, a static iron core A, a moving iron core A, an electromagnetic coil A, a valve core and an upper fixing component; The outer sleeve A comprises an outer sleeve A body, an upper end with an externally threaded boss, and a lower end with an outer peripheral edge. The outer sleeve A body is made of a non-magnetic metal material. The static iron core A comprises a static iron core A body and a central fine through hole thereof, and a lower end of the central fine through hole of the static iron core A body is provided with a lower groove; The moving iron core A is placed on the upper side of the static iron core A body inside the outer sleeve A body; The valve core includes a push rod, a sealing column and a conical outer spring, wherein the sealing column is placed in the lower groove of the static iron core A body, and the push rod is placed in the central fine through hole of the static iron core A body; The upper fixing component is used to fix the electromagnetic coil A up and down outside the outer sleeve A body; The normally open solenoid valve further includes a valve island body and a lower fixing component; The valve island body is provided with a circular groove for measuring gas, and the circular groove for measuring gas is provided with a measuring gas docking outlet and a measuring gas docking inlet; The lower fixing component fixes the outer sleeve A body to the measuring gas circular groove of the valve island body by using the outer periphery of the lower port of the outer sleeve A body; The ejector rod utilizes a sealing column to deform the conical outer spring to seal the measurement gas docking outlet; The conical outer spring is arranged between the sealing cylinder and the measurement gas docking outlet; The measurement gas docking outlet is an annular protrusion provided at the center of the measurement gas circular groove; the measurement gas docking inlet is a flat opening provided in the measurement gas circular groove and staggered from the measurement gas docking outlet; The sealing cylinder comprises a cylindrical shell with a lower opening, an inner spring and an inverted convex sealing plug with a boss on the lower end surface, which are sequentially embedded from the lower opening of the cylindrical shell. The elastic force of the inner spring is greater than that of the conical outer spring. The upper end of the conical outer spring is sleeved on the outer edge of the boss of the inverted convex sealing plug, and the lower end is sleeved on the outside of the annular protrusion in the center of the circular groove for measuring gas.

2. The normally open solenoid valve according to claim 1, wherein: The cylindrical shell with a lower opening is provided with a side wall hole.

3. The normally open solenoid valve according to claim 1 or 2, characterized in that: The diameter of the measurement gas docking inlet is larger than the diameter of the measurement gas docking outlet.

4. The normally open solenoid valve according to claim 3, wherein: The non-magnetic metal material is stainless steel, copper or aviation aluminum.

5. The normally open solenoid valve according to claim 3, wherein: The pressure of the measuring gas is 8 kPa or less.

6. The normally open solenoid valve according to claim 5, wherein: The pressure of the measuring gas is 6 kPa or less.

7. The normally open solenoid valve according to claim 3, wherein: The electromagnetic coil A comprises a coil A, a frame A, a retaining ring A and a shell A. The coil A is wound around the frame A, embedded in the shell A and fixed by the retaining ring A.

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