Switching valve of molecular sieve oxygenerator

Abstract

The utility model discloses a switching valve of a molecular sieve oxygen generator, relates to the technical field of oxygen generator accessories, and aims to solve the problem that a pilot-operated switching valve is not suitable for normal switching under the working conditions of ultra-low pressure and ultra-low flow, the switching valve comprises a main valve body and a pilot valve, the main valve body is provided with an air inlet, an air outlet, a first interface and a second interface, two groups of movable valve rod assemblies are arranged in the main valve body in parallel, the valve rod assemblies are used for controlling the air inlet to be communicated with the first connector or the second connector and controlling the air outlet to be communicated with the first connector or the second connector, a pilot air path is further arranged in the main valve body, and the pilot valve is used for controlling the on-off of the pilot air path so as to control the operation state of the valve rod assemblies. And the pilot air channel is internally provided with a one-way valve, so that the pilot type switching valve can be normally switched under the working conditions of low starting air pressure, low flow and unstable flow.

Description

Technical Field

[0001] The utility model relates to the technical field of accessories for oxygen generators, and more specifically, to a switching valve for a molecular sieve oxygen generator. Background Art

[0002] A molecular sieve oxygen generator is a device that realizes continuous oxygen production through the methods of pressurized adsorption and atmospheric desorption. The principle is to make clean air pass through an adsorption tower filled with molecular sieves. Through high-pressure adsorption, nitrogen in the air is removed, and higher-purity oxygen is produced. Then, through low-pressure desorption, the adsorbed nitrogen is released as waste gas. The adsorption tower is usually of a double-cylinder structure, and granular molecular sieves are installed in the two cylinders. When air enters the adsorption tower cylinder and the air pressure in the cylinder is increased to a set value, the molecular sieves inside will adsorb nitrogen in the air. When the adsorption capacity of the molecular sieves reaches the limit, by reducing the pressure in the cylinder, the adsorbed nitrogen can be released. Because there are two stages of "high-pressure adsorption for oxygen supply" and "low-pressure release for nitrogen discharge", continuous oxygen production cannot be achieved. Therefore, it is usually designed as a double-cylinder. That is, when one cylinder is in the "high-pressure adsorption for oxygen supply" stage, the other cylinder is in the "low-pressure release for nitrogen discharge" stage. When the molecular sieves in one cylinder reach the adsorption limit, it is switched to one cylinder for "low-pressure release for nitrogen discharge" and the other cylinder for "high-pressure adsorption for oxygen supply", and so on in a cycle to ensure that at any moment, there is a sieve barrel in the oxygen supply state, thus realizing continuous oxygen production.

[0003] The switching valve of the oxygen generator is the core switching component to realize the above two-stage cycle of "high-pressure adsorption for oxygen supply" and "low-pressure release for nitrogen discharge". Currently, the switching valves of oxygen generators include direct-acting type, pilot-operated type, and motor-driven type. The pilot-operated type uses an electromagnetic coil and an iron core as a pilot valve and consists of a main valve body and a pilot valve. Taking a diaphragm-type pilot valve as an example, the working medium of the main valve body enters the control valve cavity through the pilot valve hole. The main valve cavity and the control valve cavity act on the valve stem through the diaphragm at the same time. The force-bearing area of the diaphragm in the control valve cavity is larger than that of the diaphragm in the main valve cavity. Therefore, under the same pressure, the diaphragm in the control valve cavity generates a thrust on the valve stem, causing the control valve stem to move towards the main valve cavity direction, realizing the opening and closing of the main valve. Its characteristic is that the movement of the valve stem is realized through the pressure difference of the medium itself on the diaphragm, rather than being driven by electromagnetic force.

[0004] Since the pilot-operated solenoid valve relies on the pressure difference of the working medium itself to drive the valve stem to move, there are relatively high requirements for the smoothness of the flow rate and pressure of the working medium at the intake end. When the intake flow rate is too low, the working medium entering the valve cavity is not sufficient to drive the valve stem to move, and abnormal phenomena such as the valve stem not opening, the valve stem not opening in place, and the valve stem vibrating reciprocally during opening and closing will occur; when the intake pressure is too low, the pressure difference generated by the working medium flowing through the valve cavity is not sufficient to overcome the elastic force and inertial force of the valve stem, diaphragm, etc. At this time, the abnormal phenomenon that the valve stem does not open will occur; when the intake flow rate and working pressure are unstable, problems such as the valve stem not switching in place and the switching position of the valve stem being unstable will occur, resulting in unstable flow rate and pressure at the outlet. The above defects make the pilot-operated switching valve not suitable for application in small-flow oxygen generators, such as equipment with an oxygen production rate of 1L or 2L / min. When the oxygen supply equipment is applied in places with low air pressure and thin air such as plateaus, abnormal switching will also occur due to insufficient intake flow rate.

[0005] Therefore, how to solve the problem that the pilot-operated switching valve is not suitable for normal switching under ultra-low pressure and ultra-low flow conditions is an urgent problem to be solved by those skilled in the art at present. Summary of the Utility Model

[0006] In view of this, the purpose of the present utility model is to provide a switching valve for a molecular sieve oxygen generator. By adding a check valve in the pilot air path, it is ensured that the pilot-operated switching valve can be normally switched under the conditions of low starting air pressure, low flow rate, and unstable flow rate.

[0007] In order to achieve the above purpose, the present utility model provides the following technical solutions:

[0008] A switching valve for a molecular sieve oxygen generator, comprising: a main valve body and a pilot valve. The main valve body is communicated with the pilot valve. The main valve body is provided with an air inlet, an air outlet, a first interface and a second interface. Two sets of movable valve stem assemblies are arranged in parallel in the main valve body. The valve stem assemblies are used to control the communication between the air inlet and the first interface or the second interface, and to control the communication between the air outlet and the first interface or the second interface. A pilot air path is also arranged in the main valve body, and a check valve is arranged in the pilot air path. The pilot valve is used to control the on-off of the pilot air path to control the operating state of the valve stem assemblies.

[0009] Preferably, the valve stem assembly includes a main valve diaphragm for controlling the communication between the air inlet and the first interface or the second interface, and also includes a control diaphragm for controlling the communication between the air outlet and the first interface or the second interface. The main valve diaphragm and the control diaphragm are arranged at both ends of the valve stem of the valve stem assembly.

[0010] Preferably, an iron core for controlling the on-off of the pilot air path is arranged in the pilot valve.

[0011] Preferably, the pilot valve includes an electromagnetic coil for controlling the movement of the iron core. The electromagnetic coil is disposed on the outer periphery of the winding skeleton and is arranged inside the pilot valve. The winding skeleton is of a hollow structure, and the iron core is disposed inside the winding skeleton.

[0012] Preferably, the pilot valve further includes a spring for controlling the reset of the iron core. The spring is disposed on the outer periphery of the iron core.

[0013] Preferably, the pilot valve further includes a fixed spool for axial positioning. The fixed spool is disposed inside the winding skeleton and is located above the iron core.

[0014] Preferably, the pilot valve further includes:

[0015] A valve seat, connected to the main valve body. The valve seat is provided with a pilot air hole communicating with the main valve body;

[0016] A magnetic end cover, fixed to the valve seat. The magnetic end cover is provided with a through hole cooperating with the iron core, and the through hole communicates with the pilot air hole;

[0017] A magnetic outer frame, disposed outside the electromagnetic coil and fixed to the magnetic end cover.

[0018] Preferably, the main valve body includes:

[0019] A body, in which a pilot air passage is arranged. The body is provided with a long hole for installing a valve rod, and annular protrusions cooperating with the main valve diaphragm and the control diaphragm are arranged at both ends of the long hole;

[0020] A valve body front cover, arranged at the front end of the body;

[0021] A valve body rear cover, arranged at the rear end of the body. The valve body rear cover is provided with a control valve cavity cooperating with the control diaphragm.

[0022] Preferably, the air inlet is arranged on the valve body front cover, the air outlet is arranged at the top of the body, and the first interface and the second interface are arranged on both sides of the body and are connected to the long hole.

[0023] Preferably, the valve body rear cover is provided with an exhaust hole communicating with the pilot air hole.

[0024] The switching valve of the molecular sieve oxygen generator provided by the present utility model includes a main valve body and a pilot valve. The main valve body is communicated with the pilot valve, and the on-off of the gas paths in the main valve body and the pilot valve is controlled by the pilot valve. The main valve body is provided with an air inlet, an air outlet, a first interface and a second interface. The first interface is communicated with both the air inlet and the air outlet, and the second interface is communicated with both the air inlet and the air outlet. The communication states between the first interface and the second interface and the air inlet and the air outlet are controlled by the pilot valve. Two groups of movable valve rod assemblies are arranged in parallel in the main valve body. The valve rod assemblies are used to control the communication between the air inlet and the first interface or the second interface, and to control the communication between the air outlet and the first interface or the second interface. A pilot gas path is also arranged in the main valve body. The pilot valve is used to control the on-off of the pilot gas path to control the operating state of the valve rod assemblies, so as to control the communication between the air inlet and the first interface or the second interface, and to control the communication between the air outlet and the first interface or the second interface. A check valve is arranged in the pilot gas path to ensure that the pilot type switching valve can be normally switched under the working conditions of low starting air pressure, low flow rate and unstable flow rate. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0026] Figure 1 It is a schematic structural diagram of the molecular sieve oxygen generator provided by the present utility model;

[0027] Figure 2 It is an exploded view of the switching valve of the molecular sieve oxygen generator provided by the present utility model;

[0028] Figure 3 It is a cross-sectional view of the switching valve of the molecular sieve oxygen generator provided by the present utility model;

[0029] Figure 4 is Figure 3 a cross-sectional view of another state;

[0030] Figure 5 is Figure 4 a cross-sectional view of an abnormal state.

[0031] Reference Signs:

[0032] 01 - Main valve body, 02 - Pilot valve, 03 - Valve rod assembly;

[0033] 1 - Intake port, 2 - Outlet port, 3 - First interface, 4 - Second interface, 5 - Pilot air passage, 6 - Check valve, 7 - Main valve diaphragm, 8 - Control diaphragm, 9 - Valve stem, 10 - Iron core, 11 - Electromagnetic coil, 12 - Spring, 13 - Fixed valve core, 14 - Valve seat, 15 - Magnetic end cover, 16 - Magnetic outer frame, 17 - Body, 18 - Front cover of valve body, 19 - Rear cover of valve body. Detailed implementation manners

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] In the present invention, unless otherwise clearly defined and limited, terms such as "installation", "connection", "connection", "fixation" and the like shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0036] It should be noted that the following orientation words such as "front" and "rear" are defined based on the accompanying drawings of the specification.

[0037] The core of the present invention is to provide a switching valve for a molecular sieve oxygen generator. By adding a check valve 6 in the pilot air passage 5, it is ensured that the pilot-operated switching valve can be normally switched under the working conditions of low starting air pressure, low flow rate and unstable flow rate.

[0038] Please refer to Figure 1 and Figure 2, A switching valve for a molecular sieve oxygen generator includes a main valve body 01 and a pilot valve 02. Specifically, the main valve body 01 is in communication with the pilot valve 02, and the on-off of the gas paths in the main valve body 01 and the pilot valve 02 is controlled by the pilot valve 02. The main valve body 01 is provided with an air inlet 1, an air outlet 2, a first interface 3 and a second interface 4. The first interface 3 is in communication with both the air inlet 1 and the air outlet 2, and the second interface 4 is in communication with both the air inlet 1 and the air outlet 2. The communication states between the first interface 3 and the second interface 4 and the air inlet 1 and the air outlet 2 are controlled by the pilot valve 02. Two groups of movable valve stem assemblies 03 are arranged in parallel in the main valve body 01. The valve stem assemblies 03 are used to control the communication between the air inlet 1 and the first interface 3 or the second interface 4, and to control the communication between the air outlet 2 and the first interface 3 or the second interface 4. A pilot air path 5 is also provided in the main valve body 01. The pilot valve 02 is used to control the on-off of the pilot air path 5 to control the operating state of the valve stem assemblies 03, so as to control the communication between the air inlet 1 and the first interface 3 or the second interface 4, and to control the communication between the air outlet 2 and the first interface 3 or the second interface 4. A check valve 6 is provided in the pilot air path 5 to ensure that the pilot switching valve can be normally switched under the working conditions of low starting air pressure, low flow rate and unstable flow rate.

[0039] This switching valve belongs to an independent double-electrically controlled two-position four-way solenoid valve. The check valve 6 can have multiple forms, such as umbrella nail type, duckbill type, diaphragm type, ball bead seal ring type. Their principles are different, but the functions are the same in the end, which is to prevent the gas entering the pilot valve 02 from flowing back. It can also be replaced by an ordinary on-off valve, that is, by using an electric control or other means to disconnect the pilot air path 5 before the gas flows back.

[0040] The switching valve of the molecular sieve oxygen generator set in the above way can ensure that the pilot switching valve can be normally switched under the working conditions of low starting air pressure, low flow rate and unstable flow rate.

[0041] In the above embodiment, the valve stem assembly 03 includes a main valve diaphragm 7 for controlling the communication between the air inlet 1 and the first interface 3 or the second interface 4, and also includes a control diaphragm 8 for controlling the communication between the air outlet 2 and the first interface 3 or the second interface 4. The main valve diaphragm 7 and the control diaphragm 8 are arranged at both ends of the valve stem 9 of the valve stem assembly 03.

[0042] It should be noted that the valve stem assembly 03 is composed of two groups of main valve diaphragms 7, two groups of valve stems 9 and two groups of control diaphragms 8. The main valve diaphragm 7 and the control diaphragm 8 are fixed at the front and rear ends of the valve stem 9. When the control diaphragm 8 is subjected to a thrust force, it can drive the valve stem 9 to move forward, thereby driving the main valve diaphragm 7 to move forward, so that the air inlet 1 is in communication with the first interface 3 or the second interface 4. When the main valve diaphragm 7 is subjected to a thrust force, it can drive the valve stem 9 to move backward, thereby driving the control diaphragm 8 to move backward, so that the air outlet 2 is in communication with the first interface 3 or the second interface 4.

[0043] Among them, the pilot air passage 5 is a branch of the air inlet 1 of the main valve body 01, embedded inside the main valve body 01. The opening and closing of the pilot air passage 5 is controlled by the pilot valve 02. At the same time, a one-way valve 6 is equipped in the pilot air passage 5 to make the gas entering the pilot valve 02 have a one-way conduction property and prevent the gas in the pilot valve 02 from flowing back to the main valve body 01.

[0044] In the above situation, an iron core 10 for controlling the on-off of the pilot air passage 5 is provided inside the pilot valve 02.

[0045] It can be understood that by the repeated movement of the iron core 10, the communication and disconnection between the air guide hole of the pilot valve 02 and the control valve cavity of the main valve body 01 are controlled.

[0046] Furthermore, the pilot valve 02 includes an electromagnetic coil 11 for controlling the movement of the iron core 10. The electromagnetic coil 11 is arranged on the outer periphery of the winding skeleton and is arranged inside the pilot valve 02. The winding skeleton is of a hollow structure, and the iron core 10 is arranged inside the winding skeleton.

[0047] It should be noted that there is an electromagnetic coil 11 and a winding skeleton inside the pilot valve 02. Through the energized and de-energized states of the electromagnetic coil 11, the iron core 10 with rubber coating (the structure of the iron core 10 is a circular metal rod with rubber pads at both ends, and it is divided into forms of rubber coating, glue sticking, and glue dotting according to the manufacturing process. The iron core 10 in this embodiment is a glued iron core 10) reciprocates. Because the iron core 10 in the pilot valve 02 blocks the air guide hole of the pilot valve 02 when it is in the non-energized state, the intake air stops at the air guide hole of the pilot valve 02 and does not move forward. Therefore, in this case, the air guide hole and the control valve cavity are in a disconnected state. When energized, the iron core 10 and the fixed valve core 13 are magnetized by the magnetic field generated by the electromagnetic coil 11. According to the right-hand rule, regardless of the current direction and winding direction of the electromagnetic coil 11, the upper end of the magnetized iron core 10 and the lower end of the fixed valve core 13 are always opposite-sex magnetic poles. The iron core 10 is lifted by the suction force of the opposite-sex magnetic pole of the fixed valve core 13.

[0048] In the above embodiment, the pilot valve 02 further includes a spring 12 for controlling the reset of the iron core 10. The spring 12 is arranged on the outer periphery of the iron core 10.

[0049] It can be understood that when energized, the iron core 10 and the fixed valve core 13 are magnetized by the magnetic field generated by the electromagnetic coil 11. According to the right-hand rule, regardless of the current direction and winding direction of the electromagnetic coil 11, the upper end of the magnetized iron core 10 and the lower end of the fixed valve core 13 are always opposite-sex magnetic poles. The iron core 10 is lifted by the suction force of the opposite-sex magnetic pole of the fixed valve core 13, making the air guide hole communicate with the control valve cavity. At the same time, a pulling force is generated on the spring 12. When the electromagnetic coil 11 is de-energized, the iron core 10 is reset under the action of the spring 12, so that the air guide hole is disconnected from the control valve cavity, so that the intake air stops at the air guide hole of the pilot valve 02.

[0050] Based on the above embodiments, the pilot valve 02 further includes a fixed spool 13 for axial positioning. The fixed spool 13 is disposed within the winding skeleton and is located above the iron core 10.

[0051] It should be noted that when the electromagnetic coil 11 is energized, the iron core 10 will be lifted due to the suction force of the opposite magnetic poles of the fixed spool 13.

[0052] In the above embodiments, the pilot valve 02 further includes a valve seat 14, a magnetic conductive end cover 15, and a magnetic conductive outer frame 16. The valve seat 14 is connected to the main valve body 01. By providing the valve seat 14, the installation and positioning of other structures are realized. The valve seat 14 is provided with an air guide hole communicating with the main valve body 01. By providing the air guide hole, the pilot valve 02 is communicated with the main valve body 01. The magnetic conductive end cover 15 is fixed to the valve seat 14. The magnetic conductive end cover 15 is provided with a through hole cooperating with the iron core 10, so that the iron core 10 can be installed in the through hole and move within the through hole. The through hole is communicated with the air guide hole to realize the control of the conduction state between the air inlet 1, the air outlet 2, the first interface 3, and the second interface 4 of the main valve body 01 through the movement of the iron core 10. The magnetic conductive outer frame 16 is disposed outside the electromagnetic coil 11 and fixed to the magnetic conductive end cover 15. Through the cooperation of the magnetic conductive outer frame 16 and the valve seat 14, the protection of other internal structures is realized.

[0053] It can be understood that the pilot valve 02 is a two-position three-way solenoid valve in two groups. A single solenoid valve is fixedly composed of a valve seat 14, a magnetic conductive end cover 15, and a magnetic conductive outer frame 16 to realize the protection and positioning of its internal structure.

[0054] As a preferred embodiment, the main valve body 01 includes a body 17, a valve body front cover 18, and a valve body rear cover 19. A chamber for air passage is formed by the body 17, the valve body front cover 18, and the valve body rear cover 19. The pilot air passage 5 is disposed in the body 17. The body 17 is provided with a long hole for installing the valve rod 9. Annular protrusions cooperating with the main valve diaphragm 7 and the control diaphragm 8 are provided at both ends of the long hole. By the abutting and disconnecting states of the main valve diaphragm 7, the control diaphragm 8 and the annular protrusions, the control of the conduction state between the air inlet 1, the air outlet 2, the first interface 3, and the second interface 4 is realized. The valve body front cover 18 is disposed at the front end of the body 17, and the valve body rear cover 19 is disposed at the rear end of the body 17. The valve body rear cover 19 is provided with a control valve cavity cooperating with the control diaphragm 8. By the communication state between the control valve cavity and the air guide hole, the movement states of the main valve diaphragm 7, the control diaphragm 8, and the valve rod 9 are controlled, and further the control of the conduction state between the air inlet 1, the air outlet 2, the first interface 3, and the second interface 4 is realized.

[0055] It should be noted that the main valve body 01 is composed of a valve body front cover 18, a main body 17, and a valve body rear cover 19 to form an external skeleton. The gas medium of the main valve body 01 enters the valve body front cover 18 through the air inlet 1, applies gas pressure to the main valve diaphragm 7, and at the same time reaches the air guide hole through the pilot air path 5. When the electromagnetic coil 11 is energized, the iron core 10 is attracted and lifted by the fixed valve core 13, so that the air guide hole and the control valve cavity are communicated. Further, it enters the control valve cavity of the valve body rear cover 19 through the air guide hole. The gas medium in the control valve cavity acts on the valve stem 9 through the control diaphragm 8, so that the control diaphragm 8 in the control valve cavity generates a thrust on the valve stem 9, and the control valve stem 9 moves towards the valve body front cover 18 direction to realize the connection between the air inlet 1 and the first interface 3 or the second interface 4; when the electromagnetic coil 11 is not energized, the iron core 10 blocks the air guide hole, and the gas medium reaching the air guide hole through the pilot air path 5 stops at the air guide hole. The high-pressure gas in the control valve cavity escapes to the outside atmosphere through the pressure equalizing small hole in the middle of the fixed valve core 13, and the control valve cavity thus becomes "atmospheric pressure". At this time, the pressure hitting the main valve diaphragm 7 from the air inlet 1 is greater than the pressure in the control valve cavity, so that the main valve diaphragm 7 pushes the valve stem 9 to move towards the control valve cavity direction to realize the connection between the air outlet 2 and the first interface 3 or the second interface 4.

[0056] In the above situation, the air inlet 1 is arranged on the valve body front cover 18, the air outlet 2 is arranged at the top of the main body 17, and the first interface 3 and the second interface 4 are arranged on both sides of the main body 17 and are connected to the long hole.

[0057] It can be understood that the gas medium enters the valve body front cover 18 from the air inlet 1, flows to the air guide hole through the pilot air path 5, and then under the control of the pilot valve 02, realizes the connection between the air inlet 1 and the first interface 3 or the second interface 4, and the connection between the air outlet 2 and the first interface 3 or the second interface 4.

[0058] In the above embodiment, the valve body rear cover 19 is provided with an exhaust hole communicated with the air guide hole.

[0059] It should be noted that the gas medium in the pilot valve 02 is transported to the control valve cavity through the exhaust hole.

[0060] In this application, the main valve diaphragm 7 controls the on-off of the air inlet 1 and the first interface 3 or the second interface 4: when there is a gap between the main valve diaphragm 7 and the main body 17, the air inlet 1 is connected to the first interface 3 or the second interface 4; when the main valve diaphragm 7 is in close contact with the main body 17, the air inlet 1 is disconnected from the first interface 3 or the second interface 4; the control diaphragm 8 controls the on-off of the first interface 3 or the second interface 4 and the air outlet 2: when there is a gap between the control diaphragm 8 and the main body 17, the first interface 3 or the second interface 4 is connected to the air outlet 2; when the control diaphragm 8 is in close contact with the main body 17, the first interface 3 or the second interface 4 is disconnected from the air outlet 2.

[0061] Please refer to Figure 3, the two solenoid valves are the first solenoid valve and the second solenoid valve respectively. When both the first solenoid valve and the second solenoid valve are de-energized (low level), gas enters the main valve body 01 through the air inlet 1 (the pressure of the air inlet 1 of the oxygen generator is about 0.02 - 0.2 Mpa), and enters the pilot valve 02 through the pilot air path 5 and the one-way valve 6. Since the iron core 10 of the pilot valve 02 blocks the air guide hole of the pilot valve 02 when it is de-energized, the intake air stops advancing until the air guide hole. At this time, the pressure P0 at the air inlet 1 is equal to the pressure P1 at the air guide hole, and the pressure in the control valve cavity is the atmospheric pressure P2. The main valve diaphragm 7 and the valve stem 9 in the main valve body 01 are in a closed state. The driving force of the main valve diaphragm 7 by the intake pressure is:

[0062]

[0063] Among them, S0 is the pressure-receiving area of the main valve diaphragm 7. Under the push of this force, the main valve diaphragm 7 clings to the body 17, and the gas is not conducted. At this time, the air inlet 1 is disconnected from both the first interface 3 and the second interface 4, and the air outlet 2 is connected to both the first interface 3 and the second interface 4.

[0064] Please refer to Figure 4 , when the first solenoid valve is at a high level and the second solenoid valve is at a low level, the first solenoid valve will be lifted due to the suction force of the opposite magnetic pole of the fixed valve core 13, making the air guide hole communicate with the control valve cavity. At this time, the pressure at the air inlet 1 is equal to the pressure at the air guide hole and the pressure in the control valve cavity, and is greater than the atmospheric pressure, that is, P0 = P1 = P2 > atmospheric pressure. At this time, the thrust generated by the gas on the control diaphragm 8 is:

[0065]

[0066] Among them, the pressure-receiving area of the control diaphragm 8 is S1. According to the diaphragm structure: S1 > S0, so F2 > F1. At this time, the control diaphragm 8 deforms, blocking the channel between the air outlet 2 and the first interface 3. At the same time, the control valve stem 9 moves in the direction of the air inlet 1 under the combined force, driving the main valve diaphragm 7 to open a gap with the main body, so that the air inlet 1 is connected to the first interface 3. At the same time, the air outlet 2 is connected to the second interface 4.

[0067] Similarly, when the second solenoid valve is at a high level and the first solenoid valve is at a low level, the air inlet 1 is connected to the second interface 4, and the first interface 3 is connected to the air outlet 2.

[0068] When both the first solenoid valve and the second solenoid valve are at a high level, the air inlet 1 is connected to the first interface 3 or the second interface 4 at the same time, and the air outlet 2 is disconnected from the first interface 3 or the second interface 4 at the same time.

[0069] The above description is for a normally closed solenoid valve, that is, a high-level gas circuit is open and a low-level gas circuit is closed. If it is for a normally open solenoid valve, you only need to swap the high level and low level in the above description.

[0070] Please refer to Figure 5 In the existing products without a one-way valve 6, when the air inlet 1 is connected to the first interface 3, the gas at the air inlet 1 is quickly diverted to the first interface 3 and enters the adsorption tower. At this time, the pressure at the air inlet 1 produces an instantaneous pressure drop, which is instantly reduced to near normal pressure. At this time, the high-pressure gas entering the control valve cavity will flow back to the main valve cavity along the pilot gas path 5, causing the pressure in the control valve cavity to drop instantaneously, and the thrust generated on the control diaphragm 8 is instantly reduced, resulting in insufficient deformation of the control diaphragm 8. At this time, gaps are generated between the control diaphragm 8 and the main body, and between the main valve diaphragm 7 and the main body, which ultimately leads to the air inlet 1, the first interface 3, and the air outlet 2 being all connected. The gas entering from the air inlet 1 does not enter the two working ports of the first interface 3 and the second interface 4, and is discharged into the atmosphere from the air outlet 2, and the solenoid valve fails.

[0071] When the one-way valve 6 is added to the pilot air circuit 5, the pressure at the air inlet 1 drops instantly when the air inlet 1 is connected to the first interface 3 or the second interface 4. At this time, the one-way valve 6 closes instantly, and the gas that has flowed into the control valve cavity will not flow back to the main valve cavity, that is, there will be no instantaneous pressure drop, and the thrust on the control diaphragm 8 remains unchanged, which can ensure that the solenoid valve can switch normally under the conditions of low starting pressure, low flow, and unstable flow.

[0072] In summary, the molecular sieve oxygen generator switching valve provided by the utility model adopts a structure in which a one-way valve 6 is added to the pilot gas path 5. When the pressure at the air inlet 1 of the main valve body 01 is reduced due to diversion, the pressure in the control chamber is always equal to the peak value of the pressure change at the air inlet 1, so that the switching effect of the valve body is not affected by the diversion and airflow disturbance at the air inlet 1. It is suitable for use in oxygen generators with small flow rates such as 1L and 2L, can be used in places with thin air such as plateaus, and is suitable for use in oxygen generators in certain dusty environments.

[0073] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0074] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0075] The above has introduced in detail a switching valve of a molecular sieve oxygen generator provided by the present utility model. Specific examples are used in this article to elaborate on the principle and implementation manner of the present utility model. The description of the above embodiments is only used to help understand the method and its core idea of the present utility model. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present utility model, several improvements and modifications can be made to the present utility model, and these improvements and modifications also fall within the protection scope of the claims of the present utility model.

Claims

1. A switching valve for a molecular sieve oxygen generator, characterized in that, Comprising: A main valve body (01) and a pilot valve (02), the main valve body (01) is in communication with the pilot valve (02), the main valve body (01) is provided with an air inlet (1), an air outlet (2), a first interface (3) and a second interface (4), two groups of movable valve stem assemblies (03) are arranged in parallel in the main valve body (01), the valve stem assemblies (03) are used to control the communication between the air inlet (1) and the first interface (3) or the second interface (4), and to control the communication between the air outlet (2) and the first interface (3) or the second interface (4), a pilot air passage (5) is further provided in the main valve body (01), a check valve (6) is provided in the pilot air passage (5), and the pilot valve (02) is used to control the on-off of the pilot air passage (5) to control the operating state of the valve stem assemblies (03).

2. The switching valve of the molecular sieve oxygen generator according to claim 1, characterized in that, The valve stem assembly (03) includes a main valve diaphragm (7) for controlling the communication between the air inlet (1) and the first interface (3) or the second interface (4), and further includes a control diaphragm (8) for controlling the communication between the air outlet (2) and the first interface (3) or the second interface (4), the main valve diaphragm (7) and the control diaphragm (8) are arranged at both ends of the valve stem (9) of the valve stem assembly (03).

3. The switching valve of the molecular sieve oxygen generator according to claim 2, characterized in that, An iron core (10) for controlling the on-off of the pilot air passage (5) is provided in the pilot valve (02).

4. The switching valve of the molecular sieve oxygen generator according to claim 3, characterized in that, The pilot valve (02) includes an electromagnetic coil (11) for controlling the movement of the iron core (10), the electromagnetic coil (11) is arranged on the outer periphery of a winding skeleton and is arranged in the pilot valve (02), the winding skeleton is of a hollow structure, and the iron core (10) is arranged in the winding skeleton.

5. The switching valve of the molecular sieve oxygen generator according to claim 4, wherein The pilot valve (02) further includes a spring (12) for controlling the reset of the iron core (10), and the spring (12) is arranged on the outer periphery of the iron core (10).

6. The switching valve of the molecular sieve oxygen generator according to claim 5, characterized in that, The pilot valve (02) further includes a fixed valve core (13) for axial positioning, and the fixed valve core (13) is arranged in the winding skeleton and is located above the iron core (10).

7. The switching valve of the molecular sieve oxygen generator according to claim 6, characterized in that, The pilot valve (02) further includes: A valve seat (14), connected to the main valve body (01), and an air guide hole communicating with the main valve body (01) is provided on the valve seat (14); A magnetic conductive end cover (15), fixed to the valve seat (14), a through hole cooperating with the iron core (10) is provided on the magnetic conductive end cover (15), and the through hole communicates with the air guide hole; A magnetic conductive outer frame (16), arranged outside the electromagnetic coil (11) and fixed to the magnetic conductive end cover (15).

8. The switching valve of the molecular sieve oxygen generator according to claim 7, characterized in that, The main valve body (01) includes: A body (17), the pilot air passage (5) is arranged in the body (17), the body (17) is provided with a long hole for installing the valve stem (9), and annular protrusions cooperating with the main valve diaphragm (7) and the control diaphragm (8) are provided at both ends of the long hole; A valve body front cover (18), arranged at the front end of the body (17); The valve body rear cover (19) is provided at the rear end of the body (17), and the valve body rear cover (19) is provided with a control valve cavity that cooperates with the control diaphragm (8).

9. The switching valve of the molecular sieve oxygen generator according to claim 8, characterized in that, The air inlet (1) is provided on the valve body front cover (18), the air outlet (2) is provided at the top of the body (17), and the first interface (3) and the second interface (4) are provided on both sides of the body (17) and communicate with the long hole.

10. The switching valve of the molecular sieve oxygen generator according to claim 9, characterized in that, The valve body rear cover (19) is provided with an exhaust hole that communicates with the air guide hole.

Images