A back-drawing valve

Abstract

The present invention relates to the technical field of diesel engine exhaust after-treatment, and more particularly, to a reverse suction valve. A reverse suction valve includes a valve body, a slide valve, an elastic member, and a force amplification component. The valve body is provided with a valve passage and first, second, third, fourth, and fifth liquid ports communicating with the valve passage; the first and second liquid ports are used to communicate with a urea tank, the third and fifth liquid ports are used to communicate with a urea pump, and the fourth liquid port is used to communicate with a urea nozzle. Both the elastic member and the force amplification component are used to apply an external force to the slide valve; the slide valve slides relative to the valve passage under the external force of the elastic member and causes the first liquid port to communicate with the third liquid port, and the fourth liquid port to communicate with the fifth liquid port; the slide valve slides relative to the valve passage under the external forces of the elastic member and the force amplification component and causes the third liquid port to communicate with the fourth liquid port, and the fifth liquid port to communicate with the second liquid port. This reverse suction valve has a small structural volume and a wide application range.

Description

Technical Field

[0001] The present invention relates to the technical field of diesel engine exhaust aftertreatment, and more particularly, to a reverse suction valve. Background Art

[0002] In order to meet the increasingly stringent emission standards, it has become necessary to install an exhaust aftertreatment device on a diesel engine. The current mainstream aftertreatment technology is the SCR technology, that is, using an aqueous urea solution as a reducing agent to purify nitrogen oxides in the exhaust gas. The urea pump is an important part of the urea solution injection metering system, and its function is to provide the nozzle with a urea solution having a stable pressure. The pressurized liquid is atomized by the nozzle and sprayed into the tailpipe to chemically react with the exhaust gas, thereby removing nitrogen oxides in the exhaust gas. When the urea pump stops working, the urea solution in the pump and the pipeline should be emptied, otherwise there will be problems of residual urea crystallization or icing. Both crystallization and icing problems will greatly damage the urea pump and cause it to fail to work. Although the existing reverse valve technology can meet the functions of evacuation and back suction, its volume is relatively large. Summary of the Invention

[0003] The purpose of the present invention is to provide a reverse suction valve with a small structural volume and a wide range of applications.

[0004] The embodiments of the present invention are implemented as follows:

[0005] The present invention provides a reverse suction valve, which includes a valve body, a slide valve, an elastic member, and a force increasing component;

[0006] The valve body is provided with a valve passage and a first liquid port, a second liquid port, a third liquid port, a fourth liquid port, and a fifth liquid port that are communicated with the valve passage; the slide valve is slidably engaged with the valve passage; the first liquid port and the second liquid port are used to communicate with a urea tank, the third liquid port and the fifth liquid port are used to communicate with a urea pump, and the fourth liquid port is used to communicate with a urea nozzle;

[0007] The elastic member is disposed in the valve passage, the force increasing component is connected to the valve body, and both the elastic member and the force increasing component are used to apply an external force to the slide valve; when the external force acting on the slide valve by the force increasing component disappears, the slide valve slides relative to the valve passage to a first position under the external force of the elastic member, and makes the first liquid port communicate with the third liquid port, and the fourth liquid port communicate with the fifth liquid port; when the force increasing component applies an external force to the slide valve, the slide valve slides relative to the valve passage to a second position under the external forces of the elastic member and the force increasing component, and makes the third liquid port communicate with the fourth liquid port, and the fifth liquid port communicate with the second liquid port.

[0008] In an optional embodiment, along the opening direction of the valve passage, the elastic member and the force increasing component are respectively used to apply external forces to both ends of the slide valve; the sliding direction of the slide valve when the external force acting on the slide valve by the force increasing component disappears is opposite to the sliding direction when the force increasing component applies an external force to the slide valve.

[0009] In an optional embodiment, along the axial direction of the spool valve, a first annular groove, a second annular groove and a third annular groove are sequentially arranged on the outer peripheral surface of the spool valve;

[0010] When the spool valve is in the first position, the first liquid port and the third liquid port are both communicated with the first annular groove, and the fourth liquid port and the fifth liquid port are both communicated with the second annular groove;

[0011] When the spool valve is in the second position, the third liquid port and the fourth liquid port are both communicated with the second annular groove, and the fifth liquid port and the second liquid port are both communicated with the third annular groove.

[0012] In an optional embodiment, the back-drawing valve further includes a first annular seal ring, a second annular seal ring, a third annular seal ring and a fourth annular seal ring;

[0013] Along the axial direction of the spool valve, the first annular seal ring, the second annular seal ring, the third annular seal ring and the fourth annular seal ring are sequentially sleeved on the spool valve, and the first annular groove is located between the first annular seal ring and the second annular seal ring, the second annular groove is located between the second annular seal ring and the third annular seal ring, and the third annular groove is located between the third annular seal ring and the fourth annular seal ring.

[0014] In an optional embodiment, the force increasing component includes a force increasing cylinder, an energy storage cylinder and a solenoid valve; the solenoid valve is communicated with the energy storage cylinder and the force increasing cylinder; the force increasing cylinder is communicated with the second liquid port;

[0015] When the solenoid valve blocks the energy storage cylinder from the force increasing cylinder, the external force acting on the spool valve by the force increasing component disappears, and the spool valve moves to the first position relative to the valve passage under the action of the elastic member, and the energy storage cylinder is communicated with the fourth liquid port, and the pressurized liquid output by the urea pump enters the energy storage cylinder;

[0016] When the solenoid valve connects the energy storage cylinder with the force increasing cylinder, the pressurized liquid in the energy storage cylinder enters the force increasing cylinder, and the force increasing cylinder applies an external force to the spool valve, so that the spool valve moves to the second position relative to the valve passage.

[0017] In an optional embodiment, the valve body is further provided with a sixth liquid port communicated with the valve passage, and the sixth liquid port is communicated with the energy storage cylinder and the second annular groove;

[0018] The force increasing component further includes a check valve, the check valve is located on the pipeline connecting the sixth liquid port and the energy storage cylinder, and is used for unidirectional conduction from the sixth liquid port to the energy storage cylinder direction.

[0019] In an optional embodiment, the valve body is further provided with an energy storage cavity; the energy storage cylinder includes an energy storage piston and an energy storage spring;

[0020] The energy storage piston is slidably matched with the energy storage cavity, and the energy storage piston divides the energy storage cavity into a first chamber and a second chamber;

[0021] The energy storage spring is installed in the first chamber and is used to apply an external force to the energy storage piston to move in a direction away from the first chamber; the solenoid valve and the fourth liquid port are both connected to the second chamber.

[0022] In an optional embodiment, the solenoid valve includes a first interface, a second interface, and a third interface;

[0023] The first interface is connected to the energy storage cylinder, the second interface is connected to the second liquid port, and the third interface is connected to the force amplifier cylinder;

[0024] The solenoid valve has a first state in which the first interface and the third interface are blocked and the second interface and the third interface are connected; and a second state in which the first interface and the third interface are connected and the second interface and the third interface are blocked.

[0025] In an optional embodiment, the valve body further includes an intensifying chamber, a seventh liquid port, and an eighth liquid port; the intensifying chamber is connected to the valve passage; both the seventh liquid port and the eighth liquid port are connected to the intensifying chamber;

[0026] The force amplifier cylinder includes a force amplifier piston; along the opening direction of the valve passage, the force amplifier piston is slidably engaged with the intensifying chamber, and the force amplifier piston is used to divide the intensifying chamber into a third chamber and a fourth chamber. The third chamber is connected to the valve passage, and the seventh liquid port and the eighth liquid port are respectively connected to the third chamber and the fourth chamber; the seventh liquid port is connected to the second liquid port, and the eighth liquid port is connected to the third interface;

[0027] When the solenoid valve is in the second state, the pressurized liquid in the energy storage cylinder enters the fourth chamber through the solenoid valve, and causes the force amplifier piston to move in a direction close to the valve passage to abut against the spool valve and drive the spool valve to move to the second position.

[0028] In an optional embodiment, the force amplifier assembly includes a force amplifier electromagnet connected to the valve body;

[0029] When the force amplifier electromagnet is powered off, the spool valve moves relative to the valve passage to the first position under the action of the elastic member;

[0030] When the force amplifier electromagnet is powered on, the spool valve moves relative to the valve passage to the second position under the magnetic force of the force amplifier electromagnet.

[0031] The beneficial effects of the embodiments of the present invention include:

[0032] The reverse suction valve includes a valve body, a spool valve, an elastic member, and a force amplifier assembly. Among them, the valve body is provided with a valve passage and a first liquid port, a second liquid port, a third liquid port, a fourth liquid port, and a fifth liquid port connected to the valve passage. The first liquid port and the second liquid port are used to be connected to the urea tank, the third liquid port and the fifth liquid port are used to be connected to the urea pump, and the fourth liquid port is used to be connected to the urea nozzle; and the spool valve can slide relative to the valve passage under the external forces of the elastic member and the force amplifier assembly.

[0033] Thus, when the external force exerted by the force - increasing component on the spool valve disappears, that is, when only the elastic component acts, the spool valve slides relative to the valve passage under the external force of the elastic component to the first position, and makes the first liquid port communicate with the third liquid port, and the fourth liquid port communicate with the fifth liquid port. At this time, since the first liquid port is connected to the urea tank, the third liquid port and the fifth liquid port are both connected to the urea pump, and the fourth liquid port is connected to the urea nozzle, the liquid in the urea tank can enter the valve passage from the first liquid port, then enter the urea pump through the third liquid port for pressurization, and then be transported to the urea nozzle through the fifth liquid port and the fourth liquid port;

[0034] When the force - increasing component applies an external force to the spool valve, the spool valve slides relative to the valve passage to the second position under the external forces of the elastic component and the force - increasing component, and makes the third liquid port communicate with the fourth liquid port, and the fifth liquid port communicate with the second liquid port. Since the second liquid port is connected to the urea tank, the third liquid port and the fifth liquid port are both connected to the urea pump, and the fourth liquid port is connected to the urea nozzle, the liquid in the urea nozzle can enter the valve passage from the fourth liquid port, then enter the urea pump through the third liquid port for pressurization, and then be transported to the urea tank through the fifth liquid port and the second liquid port, thus forming a reverse suction of the liquid;

[0035] In summary, through the sliding of the spool valve in the valve passage, the reverse suction valve can change the liquid delivery direction, which can simplify the structure of the reverse suction valve while reducing the stroke of the spool valve, thereby reducing the overall structural size of the reverse suction valve, which is beneficial to the design layout of the integrated urea pump and reduces the space requirement of the reverse suction valve during use, expanding the applicable range of the reverse suction valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, so they should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0037] Figure 1 It is a schematic structural diagram of the reverse suction valve in the embodiment of the present invention;

[0038] Figure 2 It is a schematic diagram of the principle of the reverse suction valve in the embodiment of the present invention;

[0039] Figure 3 It is a schematic diagram of the principle of the force - increasing component in the embodiment of the present invention;

[0040] Figure 4 It is a schematic diagram of the principle of the valve body in the embodiment of the present invention;

[0041] Figure 5 It is a schematic diagram of the principle when the valve body is in the first position in the embodiment of the present invention;

[0042] Figure 6 This is the schematic diagram when the valve body is in the second position in the embodiment of the present invention;

[0043] Figure 7 This is the schematic diagram when the valve body is in the first position in other embodiments of the present invention;

[0044] Figure 8 This is the schematic diagram when the valve body is in the second position in other embodiments of the present invention.

[0045] Icon: 200 - back - suction valve; 210 - valve body; 220 - slide valve; 230 - elastic part; 240 - force - increasing component; 211 - valve passage; 212 - first liquid port; 213 - second liquid port; 214 - third liquid port; 215 - fourth liquid port; 216 - fifth liquid port; 10 - urea tank; 20 - urea pump; 30 - urea nozzle; 221 - first annular groove; 222 - second annular groove; 223 - third annular groove; 241 - force - increasing cylinder; 242 - energy - storage cylinder; 243 - solenoid valve; 217 - sixth liquid port; 244 - check valve; 218 - energy - storage cavity; 245 - energy - storage piston; 246 - energy - storage spring; 247 - first chamber; 248 - second chamber; 249 - first interface; 251 - second interface; 252 - third interface; 253 - force - increasing cavity; 254 - seventh liquid port; 255 - eighth liquid port; 256 - force - increasing piston; 257 - third chamber; 258 - fourth chamber; 270 - force - increasing electromagnet. Detailed implementation manners

[0046] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, 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 some but not all of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0047] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0048] It should be noted that: like reference numerals and letters denote similar items in the following accompanying drawings. Therefore, once an item is defined in one accompanying drawing, it does not need to be further defined and explained in subsequent accompanying drawings.

[0049] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of this invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0050] In addition, terms such as "horizontal" and "vertical" do not mean that the components are required to be absolutely horizontal or hanging vertically, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0051] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "install", "connect", "couple" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can 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.

[0052] Please refer to Figures 1-6 , Figures 1-3 which shows the structure of the backflow valve in the embodiment of the present invention, Figure 4 which shows the structure of the valve body in the embodiment of the present invention, Figure 5 which shows the structure of the valve body in the first position in the embodiment of the present invention, Figure 6 which shows the structure of the valve body in the second position in the embodiment of the present invention, Figure 5 and Figure 6 the direction indicated by the arrow in

[0053] This embodiment provides a backflow valve 200, and the backflow valve 200 includes a valve body 210, a slide valve 220, an elastic member 230, and a force amplification component 240.

[0054] The valve body 210 is provided with a valve passage 211 and a first liquid port 212, a second liquid port 213, a third liquid port 214, a fourth liquid port 215 and a fifth liquid port 216 that are communicated with the valve passage 211; the spool valve 220 is slidably engaged with the valve passage 211; the first liquid port 212 and the second liquid port 213 are used to communicate with the urea tank 10, the third liquid port 214 and the fifth liquid port 216 are used to communicate with the urea pump 20, and the fourth liquid port 215 is used to communicate with the urea nozzle 30.

[0055] The elastic member 230 is disposed in the valve passage 211, the force increasing component 240 is connected to the valve body 210, and both the elastic member 230 and the force increasing component 240 are used to apply an external force to the spool valve 220; when the external force applied by the force increasing component 240 to the spool valve 220 disappears, the spool valve 220 slides relative to the valve passage 211 to the first position under the external force of the elastic member 230, and makes the first liquid port 212 communicate with the third liquid port 214, and the fourth liquid port 215 communicate with the fifth liquid port 216; when the force increasing component 240 applies an external force to the spool valve 220, the spool valve 220 slides relative to the valve passage 211 to the second position under the external forces of the elastic member 230 and the force increasing component 240, and makes the third liquid port 214 communicate with the fourth liquid port 215, and the fifth liquid port 216 communicate with the second liquid port 213.

[0056] The working principle of the backflow valve 200 is as follows:

[0057] The backflow valve 200 includes a valve body 210, a spool valve 220, an elastic member 230 and a force increasing component 240. Among them, the valve body 210 is provided with a valve passage 211 and a first liquid port 212, a second liquid port 213, a third liquid port 214, a fourth liquid port 215 and a fifth liquid port 216 that are communicated with the valve passage 211. Among them, the first liquid port 212 and the second liquid port 213 are used to communicate with the urea tank 10, the third liquid port 214 and the fifth liquid port 216 are used to communicate with the urea pump 20, and the fourth liquid port 215 is used to communicate with the urea nozzle 30; and the spool valve 220 can slide relative to the valve passage 211 under the external forces of the elastic member 230 and the force increasing component 240.

[0058] Thus, when the external force applied by the force increasing component 240 to the spool valve 220 disappears, that is, when only the elastic member 230 acts, the spool valve 220 slides relative to the valve passage 211 to the first position under the external force of the elastic member 230, and makes the first liquid port 212 communicate with the third liquid port 214, and the fourth liquid port 215 communicate with the fifth liquid port 216. At this time, since the first liquid port 212 communicates with the urea tank 10, the third liquid port 214 and the fifth liquid port 216 both communicate with the urea pump 20, and the fourth liquid port 215 communicates with the urea nozzle 30, so the liquid in the urea tank 10 ( Figure 5The direction indicated by the arrow in the figure is the direction of liquid flow) can enter the valve channel 211 through the first liquid port 212, enter the urea pump 20 through the third liquid port 214 for pressurization, and then be delivered to the urea nozzle 30 through the fifth liquid port 216 and the fourth liquid port 215;

[0059] When the force-increasing assembly 240 applies an external force to the slide valve 220, the slide valve 220 slides to the second position relative to the valve passage 211 under the external force of the elastic member 230 and the force-increasing assembly 240, and the third liquid port 214 is connected to the fourth liquid port 215, and the fifth liquid port 216 is connected to the second liquid port 213. Since the second liquid port 213 is connected to the urea tank 10, the third liquid port 214 and the fifth liquid port 216 are both connected to the urea pump 20, and the fourth liquid port 215 is connected to the urea nozzle 30, the liquid in the urea nozzle 30 ( Figure 6 The direction indicated by the arrow in the figure is the direction of liquid flow) can enter the valve channel 211 through the fourth liquid port 215, enter the urea pump 20 through the third liquid port 214 for pressurization, and then be delivered to the urea tank 10 through the fifth liquid port 216 and the second liquid port 213, thereby forming a backflow of liquid;

[0060] In summary, the backflow valve 200 can change the liquid delivery direction by sliding the sliding valve 220 in the valve channel 211, thereby simplifying the structure of the backflow valve 200 and reducing the stroke of the sliding valve 220, thereby reducing the overall structural size of the backflow valve 200, which is beneficial to the design layout of the integrated urea pump 20, and reduces the space requirement of the backflow valve 200 during use, thereby expanding the scope of application of the backflow valve 200.

[0061] For further information, please refer to Figures 1-3 In this embodiment, during the movement of the sliding valve 220 in the valve channel 211, it is necessary to change its position between the first position and the second position according to the needs of use. Therefore, in order to reduce its stroke during the movement process and thus reduce the structural volume of the backflow valve 200, the elastic member 230 and the force-enhancing component 240 are respectively used to apply external forces to the two ends of the sliding valve 220 along the opening direction of the valve channel 211, and the sliding direction of the sliding valve 220 when the external force exerted by the force-enhancing component 240 on the sliding valve 220 disappears is opposite to the sliding direction when the force-enhancing component 240 applies external force to the sliding valve 220. That is, under the action of the elastic member 230 and the force-enhancing component 240, the sliding valve 220 reciprocates in the valve channel 211 and changes its position between the first position and the second position, thereby changing the flow direction of the liquid in the backflow valve 200.

[0062] Further, please refer to Figure 4, in this embodiment, when the slide valve 220 cooperates with the valve passage 211, by sliding the slide valve 220 relative to the valve passage 211, the communication state among the first liquid port 212, the second liquid port 213, the third liquid port 214, the fourth liquid port 215 and the fifth liquid port 216 can be adjusted. Therefore, along the axial direction of the slide valve 220, a first annular groove 221, a second annular groove 222 and a third annular groove 223 are sequentially arranged on the outer peripheral surface of the slide valve 220;

[0063] Please refer to Figures 2-5 , when the slide valve 220 is in the first position, both the first liquid port 212 and the third liquid port 214 are connected to the first annular groove 221, and both the fourth liquid port 215 and the fifth liquid port 216 are connected to the second annular groove 222;

[0064] Please refer to Figures 2-4 , and in combination with Figure 6 , when the slide valve 220 is in the second position, both the third liquid port 214 and the fourth liquid port 215 are connected to the second annular groove 222, and both the fifth liquid port 216 and the second liquid port 213 are connected to the third annular groove 223.

[0065] During this process, in order to improve the sealing performance of the contact surface between the valve passage 211 and the slide valve 220, the backflush valve 200 further includes a first annular seal ring, a second annular seal ring, a third annular seal ring and a fourth annular seal ring; along the axial direction of the slide valve 220, the first annular seal ring, the second annular seal ring, the third annular seal ring and the fourth annular seal ring are sequentially sleeved on the slide valve 220, and the first annular groove 221 is located between the first annular seal ring and the second annular seal ring, the second annular groove 222 is located between the second annular seal ring and the third annular seal ring, and the third annular groove 223 is located between the third annular seal ring and the fourth annular seal ring. With such a setting method, since the first annular seal ring, the second annular seal ring, the third annular seal ring and the fourth annular seal ring all form an initial compression amount by relying on the structure, it can avoid leakage and pressure fluctuations and is not affected by the position accuracy of the slide valve 220, thereby improving the sealing ability and the accuracy of injection metering.

[0066] Further, please refer to Figures 1-6 , in this embodiment, when setting the force increasing component 240, the force increasing component 240 may include a force increasing cylinder 241, an energy storage cylinder 242 and a solenoid valve 243; the solenoid valve 243 is connected to the energy storage cylinder 242 and the force increasing cylinder 241; the force increasing cylinder 241 is connected to the second liquid port 213.

[0067] Among them, when the solenoid valve 243 blocks the energy storage cylinder 242 from the force amplifying cylinder 241, the external force exerted by the force amplifying component 240 on the spool valve 220 disappears. The spool valve 220 moves relative to the valve passage 211 to the first position under the action of the elastic component 230, and makes the first liquid port 212 communicate with the third liquid port 214, and the fourth liquid port 215 communicate with the fifth liquid port 216. Therefore, the liquid in the urea tank 10 can enter the valve passage 211 from the first liquid port 212, enter the urea pump 20 through the third liquid port 214 for pressurization, and then be transported to the urea nozzle 30 through the fifth liquid port 216 and the fourth liquid port 215. At the same time, the pressurized liquid output by the urea pump 20 enters the energy storage cylinder 242, so that the energy storage cylinder 242 stores pressurized liquid;

[0068] When the solenoid valve 243 connects the energy storage cylinder 242 with the force amplifying cylinder 241, the pressurized liquid in the energy storage cylinder 242 enters the force amplifying cylinder 241, and the force amplifying cylinder 241 applies an external force to the spool valve 220 to make the spool valve 220 move relative to the valve passage 211 to the second position. Therefore, the liquid in the urea nozzle 30 can enter the valve passage 211 from the fourth liquid port 215, enter the urea pump 20 through the third liquid port 214 for pressurization, and then be transported to the urea tank 10 through the fifth liquid port 216 and the second liquid port 213, thus forming a reverse suction of the liquid.

[0069] In the above process, in order to enable the liquid in the valve passage 211 to enter the energy storage cylinder 242, the valve body 210 is further provided with a sixth liquid port 217 communicating with the valve passage 211. The sixth liquid port 217 is communicated with the energy storage cylinder 242 and the second annular groove 222; in addition, in order to prevent the liquid in the energy storage cylinder 242 from flowing back into the valve passage 211, the force amplifying component 240 further includes a check valve 244. The check valve 244 is located on the pipeline connecting the sixth liquid port 217 and the energy storage cylinder 242, and is used for one-way conduction from the sixth liquid port 217 to the energy storage cylinder 242.

[0070] Based on the above content, please refer to Figures 1-6 , when setting the energy storage cylinder 242, the solenoid valve 243 and the force amplifying cylinder 241, the following setting method can be adopted:

[0071] The valve body 210 is further provided with an energy storage cavity 218; the energy storage cylinder 242 includes an energy storage piston 245 and an energy storage spring 246; the energy storage piston 245 is slidably fitted with the energy storage cavity 218, and the energy storage piston 245 divides the energy storage cavity 218 into a first chamber 247 and a second chamber 248; the energy storage spring 246 is installed in the first chamber 247 and is used for applying an external force to the energy storage piston 245 to move in a direction away from the first chamber 247; both the solenoid valve 243 and the fourth liquid port 215 are communicated with the second chamber 248.

[0072] The solenoid valve 243 includes a first interface 249, a second interface 251 and a third interface 252; the first interface 249 is connected to the energy storage cylinder 242, the second interface 251 is connected to the second liquid port 213, and the third interface 252 is connected to the force amplifier cylinder 241; the solenoid valve 243 has a first state in which the first interface 249 and the third interface 252 are blocked and the second interface 251 and the third interface 252 are connected; and a second state in which the first interface 249 and the third interface 252 are connected and the second interface 251 and the third interface 252 are blocked.

[0073] The valve body 210 further includes a force amplifier chamber 253, a seventh liquid port 254 and an eighth liquid port 255; the force amplifier chamber 253 is connected to the valve passage 211; both the seventh liquid port 254 and the eighth liquid port 255 are connected to the force amplifier chamber 253; the force amplifier cylinder 241 includes a force amplifier piston 256; along the opening direction of the valve passage 211, the force amplifier piston 256 slidably cooperates with the force amplifier chamber 253, and the force amplifier piston 256 is used to divide the force amplifier chamber 253 into a third chamber 257 and a fourth chamber 258, the third chamber 257 is connected to the valve passage 211, and the seventh liquid port 254 and the eighth liquid port 255 are respectively connected to the third chamber 257 and the fourth chamber 258; the seventh liquid port 254 is connected to the second liquid port 213, and the eighth liquid port 255 is connected to the third interface 252; when the solenoid valve 243 is in the second state, the pressurized liquid in the energy storage cylinder 242 enters the fourth chamber 258 through the solenoid valve 243, and causes the force amplifier piston 256 to move in the direction close to the valve passage 211, so as to abut against the spool valve 220 and drive the spool valve 220 to move to the second position.

[0074] Therefore, based on the above content, please refer to Figures 1-6 , the working process of the backflow valve 200 is as follows:

[0075] When the solenoid valve 243 is in the first working state, at this time, the first interface 249 and the third interface 252 are blocked, and the second interface 251 and the third interface 252 are connected. At this time, the energy storage cylinder 242 and the force amplifier cylinder 241 are blocked. The spool valve 220 moves to the first position under the action of the elastic member 230, and makes the first liquid port 212 and the third liquid port 214 connected, and the fourth liquid port 215 and the fifth liquid port 216 connected. The liquid in the urea tank 10 can enter the valve passage 211 from the first liquid port 212, then enter the urea pump 20 for pressurization through the third liquid port 214, and then be transported to the urea nozzle 30 through the fifth liquid port 216 and the fourth liquid port 215. At the same time, the pressurized liquid output by the urea pump 20 enters the energy storage cylinder 242, so that the energy storage cylinder 242 stores pressurized liquid;

[0076] When the solenoid valve 243 is in the second working state, the first interface 249 is connected to the third interface 252, the second interface 251 is blocked from the third interface 252, the energy storage cylinder 242 is connected to the force amplifier cylinder 241, and the pressurized liquid in the energy storage cylinder 242 enters the fourth chamber 258 through the solenoid valve 243, causing the force amplifier piston 256 to move in the direction close to the valve passage 211 to abut against the spool valve 220 and drive the spool valve 220 to move to the second position. Then, the liquid in the urea nozzle 30 can enter the valve passage 211 through the fourth liquid port 215, enter the urea pump 20 through the third liquid port 214 for pressurization, and then be transported to the urea tank 10 through the fifth liquid port 216 and the second liquid port 213, thus forming a reverse suction of the liquid.

[0077] Please refer to Figures 1-8 , Figure 7 and Figure 8 which show the structures of the reverse suction valves in other embodiments of the present invention. Figure 7 and Figure 8 The direction indicated by the arrow in is the liquid flow direction; in other embodiments of the present invention, the force amplifier assembly 240 may further include a force amplifier electromagnet 270 connected to the valve body 210; when the force amplifier electromagnet 270 is powered off, the spool valve 220 moves to the first position relative to the valve passage 211 under the action of the elastic member 230; when the force amplifier electromagnet 270 is powered on, the spool valve 220 moves to the second position relative to the valve passage 211 under the magnetic force of the force amplifier electromagnet 270.

[0078] The above are only specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A backflow valve, characterized in that: The backflow valve includes a valve body, a sliding valve, an elastic member and a force-increasing component; The valve body defines a valve passage and a first liquid port, a second liquid port, a third liquid port, a fourth liquid port, and a fifth liquid port connected to the valve passage; the slide valve slidably engages with the valve passage; the first liquid port and the second liquid port are used to communicate with the urea tank, the third liquid port and the fifth liquid port are used to communicate with the urea pump, and the fourth liquid port is used to communicate with the urea nozzle; The elastic member is arranged in the valve channel, the force-boosting assembly is connected to the valve body, and the elastic member and the force-boosting assembly are both used to apply an external force to the slide valve; when the external force applied to the slide valve by the force-boosting assembly disappears, the slide valve slides to a first position relative to the valve channel under the external force of the elastic member, and the first liquid port is connected to the third liquid port, and the fourth liquid port is connected to the fifth liquid port; when the force-boosting assembly applies an external force to the slide valve, the slide valve slides to a second position relative to the valve channel under the external force of the elastic member and the force-boosting assembly, and the third liquid port is connected to the fourth liquid port, and the fifth liquid port is connected to the second liquid port; Along the opening direction of the valve channel, the elastic member and the force-boosting assembly are respectively used to apply external forces to both ends of the slide valve; the sliding direction of the slide valve when the external force applied by the force-boosting assembly to the slide valve disappears is opposite to the sliding direction when the force-boosting assembly applies external force to the slide valve; Along the axial direction of the slide valve, the outer peripheral surface of the slide valve is sequentially provided with a first annular groove, a second annular groove and a third annular groove; When the slide valve is in the first position, the first liquid port and the third liquid port are both connected to the first annular groove, and the fourth liquid port and the fifth liquid port are both connected to the second annular groove; When the slide valve is in the second position, the third liquid port and the fourth liquid port are both in communication with the second annular groove, and the fifth liquid port and the second liquid port are both in communication with the third annular groove; The backflow valve further comprises a first annular sealing ring, a second annular sealing ring, a third annular sealing ring and a fourth annular sealing ring; Along the axial direction of the sliding valve, the first annular sealing ring, the second annular sealing ring, the third annular sealing ring and the fourth annular sealing ring are sequentially sleeved on the sliding valve, and the first annular groove is located between the first annular sealing ring and the second annular sealing ring, the second annular groove is located between the second annular sealing ring and the third annular sealing ring, and the third annular groove is located between the third annular sealing ring and the fourth annular sealing ring; The booster assembly includes a booster cylinder, an energy storage cylinder, and a solenoid valve; the solenoid valve is connected to the energy storage cylinder and the booster cylinder; the booster cylinder is connected to the second fluid port; When the solenoid valve blocks the energy storage cylinder from the booster cylinder, the external force of the booster assembly acting on the slide valve disappears, and the slide valve moves to the first position relative to the valve channel under the action of the elastic member. The energy storage cylinder is connected to the fourth liquid port, and the pressurized liquid output by the urea pump enters the energy storage cylinder. When the solenoid valve connects the energy storage cylinder and the booster cylinder, the pressurized liquid in the energy storage cylinder enters the booster cylinder and causes the booster cylinder to apply an external force to the slide valve, so that the slide valve moves to the second position relative to the valve channel.

2. The backflow valve according to claim 1, characterized in that: The valve body is further provided with a sixth liquid port communicating with the valve channel, and the sixth liquid port is communicated with the energy storage cylinder and the second annular groove; The force-boosting assembly further includes a one-way valve, which is located on a pipeline connecting the sixth liquid port and the energy storage cylinder and is used for one-way conduction from the sixth liquid port to the energy storage cylinder.

3. The backflow valve according to claim 1, characterized in that: The valve body is also provided with an energy storage cavity; the energy storage cylinder includes an energy storage piston and an energy storage spring; The energy storage piston is slidably engaged with the energy storage cavity, and the energy storage piston divides the energy storage cavity into a first chamber and a second chamber; The energy storage spring is installed in the first chamber and is used to apply an external force to the energy storage piston to move away from the first chamber; the solenoid valve and the fourth liquid port are both connected to the second chamber.

4. The backflow valve according to claim 1, characterized in that: The solenoid valve includes a first interface, a second interface and a third interface; The first interface is connected to the energy storage cylinder, the second interface is connected to the second liquid port, and the third interface is connected to the booster cylinder; The solenoid valve has a first state in which the first port and the third port are blocked and the second port and the third port are connected; and a second state in which the first port and the third port are connected and the second port and the third port are blocked.

5. The backflow valve according to claim 4, characterized in that: The valve body further includes a force-increasing chamber, a seventh liquid port, and an eighth liquid port; the force-increasing chamber is in communication with the valve channel; the seventh liquid port and the eighth liquid port are both in communication with the force-increasing chamber; The booster cylinder includes a booster piston; along the opening direction of the valve channel, the booster piston is slidably engaged with the booster chamber, and the booster piston is used to separate the booster chamber into a third chamber and a fourth chamber, the third chamber is communicated with the valve channel, the seventh liquid port and the eighth liquid port are communicated with the third chamber and the fourth chamber respectively; the seventh liquid port is communicated with the second liquid port, and the eighth liquid port is communicated with the third interface; When the solenoid valve is in the second state, the pressurized liquid in the energy storage cylinder enters the fourth chamber through the solenoid valve, causing the booster piston to move toward the valve path to abut against the slide valve and drive the slide valve to move to the second position.

6. The backflow valve according to claim 1, characterized in that: The force-boosting assembly includes a force-boosting electromagnet connected to the valve body; When the boosting electromagnet is de-energized, the slide valve moves to the first position relative to the valve channel under the action of the elastic member; When the boosting electromagnet is energized, the slide valve moves to the second position relative to the valve path under the magnetic force of the boosting electromagnet.

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