Pump core device, urea pump and selective catalytic reduction system

Abstract

The present disclosure relates to a pump core device, a urea pump, and a selective catalytic reduction system. The pump core device includes: an integrated cavity seat, which includes a liquid inlet pipeline and a liquid outlet pipeline; and a delivery pump component, which is arranged in the integrated cavity seat and includes a delivery liquid inlet end communicated with the liquid inlet pipeline and a delivery liquid outlet end communicated with the liquid outlet pipeline. The pump core device further includes a reflux component, which is arranged inside the integrated cavity seat and includes a reflux liquid inlet end and a reflux liquid outlet end. Wherein, the reflux liquid inlet end is communicated with the liquid outlet pipeline and the reflux liquid outlet end is communicated with the liquid inlet pipeline, so as to enable the solution output from the delivery liquid outlet end to reflux to the delivery liquid inlet end. Through such a pump core device, the pipeline components are reduced, the installation space is saved, and the cost is reduced; at the same time, the reflux distance is shortened, the delivery efficiency of the pump is improved, and the service life of the pump is prolonged.

Description

Technical Field

[0001] The present disclosure relates to the technical field of diesel engine exhaust aftertreatment, and in particular to a pump core device, a urea pump and a selective catalytic reduction system. Background Art

[0002] The diesel engine selective catalytic reduction (SCR) system usually includes a urea solution storage tank, a urea pump, a dosing module, a urea solution connecting pipeline between them, and a catalytic muffler arranged on the exhaust gas emission pipeline of the diesel engine. The delivery pump of the urea pump delivers the urea solution from the storage tank to the dosing module through the delivery line, and the dosing module sprays the urea solution into the exhaust emission pipeline before the catalytic muffler. The urea solution vaporizes under the action of the high-temperature exhaust gas discharged by the diesel engine to produce ammonia, and then the ammonia enters the SCR catalyst to undergo an oxidation-reduction reaction with the nitrogen oxides in the exhaust gas, and finally generates nitrogen and water, thereby achieving the purpose of reducing the nitrogen oxide emissions of the diesel engine; when the diesel engine is stopped, in order to prevent the urea solution remaining between the delivery pump and the dosing module from freezing at low temperature and thus freezing and cracking the equipment and pipelines, the urea pump's withdrawal pump withdraws it to the urea solution storage tank through the withdrawal line.

[0003] Existing non-air-assisted urea pump pipeline mechanism (such as Figure 1 The urea pump is a urea pump that is used for the urea solution. The urea solution is a urea solution ...

[0004] This structural setting is relatively scattered and complicated, which wastes space and causes non-centralized heating. It is necessary to set up a special reflux heating pipeline to heat and thaw the reflux pipeline mechanism at low temperatures, which increases the cost and increases the difficulty of thawing. In addition, the reflux pipeline is too long, which increases the load of the delivery pump; and the reciprocating cycle in which the overflow solution directly flows back to the storage tank and is then extracted from the storage tank again by the delivery pump greatly increases the delivery power of the delivery pump, reduces the service life of the delivery pump, and also reduces the working efficiency of the urea pump.

[0005] Therefore, it is necessary to provide a urea pump that can save pipelines and heating pipelines to save space and reduce costs, and can improve the delivery efficiency of the pump and extend the service life of the pump. Summary of the invention

[0006] This section provides a general overview of the present disclosure, rather than a full disclosure of the entire scope or all features of the present disclosure.

[0007] One object of the present disclosure is to provide a urea pump that can save pipeline and heating pipeline to save space and reduce costs.

[0008] Another object of the present disclosure is to provide a urea pump that can improve the delivery efficiency of the pump and extend the service life of the pump.

[0009] To achieve one or more of the above objects, according to one aspect of the present disclosure, there is provided a pump core device, including:

[0010] An integrated cavity seat, which includes a liquid inlet pipeline and a liquid outlet pipeline; and

[0011] A delivery pump component, which is arranged in the integrated cavity seat and includes a delivery liquid inlet end communicated with the liquid inlet pipeline and a delivery liquid outlet end communicated with the liquid outlet pipeline,

[0012] The pump core device further includes a reflux component, which is arranged inside the integrated cavity seat and includes a reflux liquid inlet end and a reflux liquid outlet end, wherein the reflux liquid inlet end is communicated with the liquid outlet pipeline and the reflux liquid outlet end is communicated with the liquid inlet pipeline, so as to enable the solution output from the delivery liquid outlet end to reflux to the delivery liquid inlet end.

[0013] In the above pump core device, a back-pumping pump component may further be included, which is arranged in the integrated cavity seat and includes a back-pumping liquid inlet end communicated with the liquid outlet pipeline and a back-pumping liquid outlet end communicated with the liquid inlet pipeline.

[0014] In the above pump core device, the delivery pump component and the back-pumping pump component may be respectively arranged at opposite ends of the integrated cavity seat.

[0015] In the above pump core device, the reflux component may include:

[0016] A throttle valve body, which defines a throttle orifice therein;

[0017] A throttle valve seat, which is hollow and one end of which is connected to the throttle valve body to define an internal space therein, and the throttle valve seat is provided with a valve stem holding portion inside; and

[0018] A T-shaped valve stem and a return spring arranged in the internal space, the T-shaped valve stem is held in the valve stem holding portion and can slide in the valve stem holding portion to open and close the throttle orifice, and one end of the return spring is connected to the throttle valve seat and the other end is connected to the T-shaped valve stem, so as to act on the T-shaped valve stem in the direction of closing the throttle orifice.

[0019] In the above pump core device, the return spring can be set to contract in a direction opposite to the above direction when the pump pressure of the delivery pump component reaches the calibrated value, so as to open the throttle hole by the T-shaped valve stem.

[0020] In the above pump core device, the T-shaped valve stem can be made of a material with soft magnetic properties, and an electromagnetic adsorption device can be provided at the end of the reflux component close to the T-shaped valve stem, so as to energize the electromagnetic adsorption device to generate a magnetic suction force on the T-shaped valve stem when the pump pressure of the delivery pump component reaches the calibrated value, so that the T-shaped valve stem overcomes the elastic force of the return spring to open the throttle hole.

[0021] In the above pump core device, the liquid outlet end of the throttle hole can be configured as a small hole with a pore diameter smaller than that of the throttle hole, wherein the pore diameter of the small hole ranges from 0.2 mm to 0.8 mm.

[0022] In the above pump core device, the reflux component can include:

[0023] A throttle valve body which defines a throttle hole inside;

[0024] A throttle valve seat which is arranged separately from the throttle valve body and is provided with a valve stem holding part inside;

[0025] A T-shaped valve stem which is held in the valve stem holding part and can slide in the valve stem holding part to open and close the throttle hole; and

[0026] A return spring, one end of which is connected to one end of the throttle valve seat and the other end is connected to the T-shaped valve stem, so as to act on the T-shaped valve stem in a direction to close the throttle hole.

[0027] According to another aspect of the present disclosure, a urea pump is provided, which includes the pump core device according to any one of the preceding paragraphs.

[0028] According to still another aspect of the present disclosure, a selective catalytic reduction system is provided, which includes the urea pump according to the previous paragraph.

[0029] According to the present disclosure, by integrating the reflux component into the integrated cavity seat of the pump core device and enabling it to return all or part of the solution transported by the delivery pump component to the liquid inlet end of the delivery pump component for re-liquefying, the reflux pipeline and the corresponding heating pipeline originally placed outside the urea pump can be reduced, thereby saving space and reducing costs. At the same time, the reflux distance is shortened, thereby improving the delivery efficiency of the pump and prolonging the service life of the pump.

[0030] Through the following detailed description of the exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, the above features and advantages of the present disclosure and other features and advantages will become clearer. Description of the Drawings

[0031] Figure 1 is a schematic diagram of an SCR system of the prior art;

[0032] Figure 2 is a cross-sectional view of a pump core device according to an embodiment of the present disclosure;

[0033] Figure 3 is a cross-sectional view of an integrated cavity seat of a pump core device according to an embodiment of the present disclosure;

[0034] Figure 4 is Figure 2 a cross-sectional view of a delivery pump component of the pump core device shown in;

[0035] Figure 5 schematically shows Figure 2 the working principle of the pump core device shown in;

[0036] Figure 6 is a cross-sectional view of a reflux component according to an embodiment of the present disclosure;

[0037] Figure 7 is a cross-sectional view of a reflux component according to another embodiment of the present disclosure;

[0038] Figure 8 is Figure 2 a cross-sectional view of a back-pumping pump component of the pump core device shown in, wherein the cross-sectional view also shows a reflux component integrally installed in a cavity seat body of the integrated cavity seat; and

[0039] Figure 9 schematically shows a reflux component of the active opening and closing type according to an embodiment of the present disclosure. Detailed Embodiments

[0040] The present disclosure will be described in detail below with reference to the accompanying drawings and by means of exemplary embodiments. It should be noted that the following detailed description of the present disclosure is for illustrative purposes only and is in no way a limitation of the present disclosure. In addition, the same reference numerals are used to denote the same components in the respective drawings.

[0041] In as Figure 1In the prior art SCR system shown, the delivery pipeline mechanism 1001 and the back-pumping pipeline mechanism 1002 are integrated in the integrated cavity seat 1000, while the reflux pipeline mechanism 1003 is arranged outside the urea pump to directly reflux the overflow solution delivered through the reflux pipeline mechanism 1003 to the urea solution storage tank 1004. This structural arrangement requires a dedicated reflux heating pipe to heat and thaw the reflux pipeline mechanism 1003 at low temperatures, such as in winter, increasing the cost and the difficulty of thawing; in addition, the external reflux pipeline is too long, increasing the load on the delivery pump in the urea pump; moreover, the reciprocating cycle of the overflow solution directly refluxing into the storage tank 1004 and then being pumped from the storage tank 1004 again by the delivery pump greatly increases the delivery power of the delivery pump, reducing the service life of the delivery pump and also reducing the working efficiency of the urea pump.

[0042] To solve the above problems, as Figure 2 shown, according to an embodiment of the present disclosure, there is provided a pump core device 1, including:

[0043] An integrated cavity seat 10, which includes a liquid inlet pipeline 10a and a liquid outlet pipeline 10b;

[0044] A delivery pump component 11, which is arranged in the integrated cavity seat 10 and includes a delivery liquid inlet end 11a communicating with the liquid inlet pipeline 10a and a delivery liquid outlet end 11b communicating with the liquid outlet pipeline 10b; and

[0045] A back-pumping pump component 12, which is arranged in the integrated cavity seat 10 and includes a back-pumping liquid inlet end 12a communicating with the liquid outlet pipeline 10b and a back-pumping liquid outlet end 12b communicating with the liquid inlet pipeline 10a,

[0046] The pump core device 1 further includes a reflux component 13, which is arranged inside the integrated cavity seat 10 and includes a reflux liquid inlet end 13a and a reflux liquid outlet end 13b, wherein the reflux liquid inlet end 13a communicates with the liquid outlet pipeline 10b and the reflux liquid outlet end 13b communicates with the liquid inlet pipeline 10a, so as to enable the solution output from the delivery liquid outlet end 11b to reflux to the delivery liquid inlet end 11a.

[0047] Through the above structure, without changing the working principles of the existing transfer pump component and the back-pumping pump component, a reflux component can be integrally installed inside the integrated cavity seat. Thus, the excess solution transported by the transfer pump component can be refluxed to the liquid inlet end of the transfer pump component through the reflux component in the integrated cavity seat built into the pump core for direct liquid feeding. In this way, pipelines and corresponding heat dissipation mechanisms such as heating pipelines are saved, thereby saving installation space and reducing costs; at the same time, the load on the transfer pump component is reduced due to the shortening of the reflux pipeline, and the liquid feeding efficiency of the transfer pump component is improved due to the circulating liquid feeding, and the service life of the transfer pump component and thus the urea pump is extended; in addition, since the integrated reflux component reduces the gas in the output pipeline, the pump pressure stability is enhanced.

[0048] On the other hand, all are integrally arranged inside the integrated cavity seat, enabling all pipelines inside the integrated cavity seat to be heated by fewer or even one heat source for thawing. Moreover, the length of the pipelines inside the pump core constructed in this way is short, resulting in less residual liquid inside during the shutdown state, effectively reducing the ice formation volume, and thus improving the anti-freezing performance of the pump.

[0049] Referring to Figure 2 and Figure 3 , the integrated cavity seat 10 is composed of a cavity seat body 101 and a process plug 102 for plugging the cavity seat body 101. The cavity seat body 101 has a liquid inlet pipeline 10a, a liquid outlet pipeline 10b, a liquid inlet port 10c, a liquid outlet port 10d, a transfer pump hollow cavity for integrating the transfer pump component 11, a back-pumping pump hollow cavity for integrating the back-pumping pump component 12, and an internal hollow cavity for integrating the reflux component 13. Among them, the liquid inlet pipeline 10a is communicated with the transfer pump hollow cavity, the back-pumping pump hollow cavity, and the internal hollow cavity, and the liquid outlet pipeline 10b is communicated with the transfer pump hollow cavity, the back-pumping pump hollow cavity, and the internal hollow cavity. The process plug 102 plugs the cavity seat body 101 at the internal hollow cavity.

[0050] As Figure 2 and Figure 4 shown, the transfer pump component 11 according to an embodiment of the present disclosure is integrally arranged in the transfer pump hollow cavity of the integrated cavity seat 10 at one end of the integrated cavity seat 10, and includes a transfer liquid inlet end 11a communicated with the liquid inlet pipeline 10a and a transfer liquid outlet end 11b communicated with the liquid outlet pipeline 10b. The transfer pump component 11 is composed of a transfer diaphragm 111, a transfer valve core 112, a transfer inlet valve 113, a transfer discharge valve 114, and a sealing valve plate 115.

[0051] Specifically, one end of the transfer diaphragm 111 is capable of providing a reciprocating motion up and down (such as Figure 2It is connected to the mechanism shown by the arrow above in the middle, and a cavity 118 is formed between the other end and the conveying valve core 112. A negative pressure is generated by the upward movement of the conveying diaphragm 111 to convey the solution from the conveying inlet valve 113 into the cavity 118, and a positive pressure is generated by the downward movement of the conveying diaphragm 111 to output the solution in the cavity 118 from the conveying discharge valve 114.

[0052] The conveying valve core 112 is provided with hole groups 112a and 112b that respectively connect the cavity 118 with the conveying liquid inlet end 11a and the conveying liquid outlet end 11b, and thus connect with the liquid inlet pipeline 10a and the liquid outlet pipeline 10b.

[0053] The conveying inlet valve 113 is composed of the conveying valve core 112 and the umbrella valve 117. The umbrella valve 117 includes a rod part and an umbrella-shaped part connected to one end of the rod part. Among them, the rod part passes through the conveying valve core 112 and the umbrella-shaped part is located on the upper surface of the conveying valve core 112. When the conveying diaphragm 111 moves downward to generate a positive pressure, the umbrella-shaped part is fixed on the conveying valve core 112 to close the hole group 112a and form a first sealing surface A1 (see Figure 5 ), and when the conveying diaphragm 111 moves upward to generate a negative pressure, the umbrella-shaped part leaves the conveying valve core 112 to open the hole group 112a, so that the hole group 112a can be unidirectionally sealed through the umbrella valve 117.

[0054] The conveying discharge valve 114 is composed of the conveying valve core 112, the sealing valve plate 115 and the spring 118. The sealing valve plate 115 is installed between the conveying valve core 112 and the cavity seat body 101 to isolate the conveying inlet valve 113 and the conveying discharge valve 114. The spring 118 is arranged at the liquid outlet of the hole group 112b, and one end of it is connected to the sealing valve plate 115, while the other end is fixed to the cavity seat body 101. The spring 118 is in a compressed state under normal conditions to make the sealing valve plate 115 seal the hole group 112b. When the conveying diaphragm 111 moves downward to generate a positive pressure, the sealing valve plate 115 moves downward to open the hole group 112b, and when the conveying diaphragm 111 moves upward to generate a negative pressure, the sealing valve plate 115 moves upward under the action of the spring 118 to close the hole group 112b and form a second sealing surface A2 (see Figure 5 ).

[0055] It should be noted that the conveying pump component 11 can also be other forms of pumps, such as gear pumps, plunger pumps, vane pumps, etc.

[0056] In addition, as Figure 2 and Figure 8As shown, the backflush pump component 12 according to an embodiment of the present disclosure is integrated in the backflush pump cavity of the integrated cavity seat 10 at one end of the integrated cavity seat 10, and includes a backflush inlet end 12a communicating with the liquid outlet pipeline 10b and a backflush outlet end 12b communicating with the liquid inlet pipeline 10a. The backflush pump component 12 is composed of a backflush diaphragm 121, a backflush valve core 122, and a backflush valve plate 123.

[0057] Specifically, one end of the backflush diaphragm 121 is connected to a mechanism that can provide reciprocating up and down movement (as shown by the arrow below in Figure 2 ), and a cavity 124 is formed between the other end and the backflush valve core 122, so as to backflush the solution from the backflush inlet valve 125 into the cavity 124 by generating negative pressure when the backflush diaphragm 121 moves downward, and output the solution in the cavity 124 from the backflush discharge valve 126 by generating positive pressure when the backflush diaphragm 121 moves upward. The backflush valve core 122 is provided with hole groups 122a and 122b that respectively communicate the cavity 124 with the backflush inlet end 12a and the backflush outlet end 12b, and thus communicate with the liquid outlet pipeline 10b and the liquid inlet pipeline 10a. The backflush inlet valve 125 is composed of a cavity seat body 101 and a backflush valve plate 123. And the backflush discharge valve 126 is composed of a backflush valve plate 123 and a backflush valve core 122. The hole groups 122a and 122b are respectively sealed unidirectionally through the backflush valve plate 123 to form a third sealing surface A3 and a fourth sealing surface A4 (see Figure 5 ).

[0058] It can be understood that the backflush pump component 12 can also be other forms of pumps.

[0059] It can be envisioned that the delivery pump component 11 and the backflush pump component 12 can be respectively arranged at opposite ends of the integrated cavity seat 10. That is to say, the delivery pump cavity and the backflush pump cavity can be respectively constructed at opposite ends of the integrated cavity seat 10. Here, the two ends refer to the opposite sides of the integrated cavity seat, as shown in Figure 2 . Thus, a more reasonable layout of the pipelines in the integrated cavity seat 10 can be allowed. However, it can be understood that the delivery pump component 11 and the backflush pump component 12 can also be arranged at other positions of the integrated cavity seat 10, for example, on the same side.

[0060] It can also be envisioned that the pump core device 1 may not include the backflush pump component 12, that is, only include the delivery pump component 11 and the reflux component 13. In this case, the pump core device 1 can still achieve the various advantages brought by the built-in reflux component 13 mentioned above.

[0061] Next, the reflux component 13 will be described in detail in conjunction with Figure 2 , Figure 6 , Figure 7 and Figure 9 .

[0062] The reflux component 13 is disposed in the internal hollow cavity of the integrated cavity base 10, and includes a reflux inlet end 13a communicating with the liquid outlet pipeline 10b and a reflux outlet end 13b communicating with the liquid inlet pipeline 10a. Refer to Figure 2 and Figure 6 , which shows a reflux component 13 according to an embodiment of the present disclosure, which can be entirely fixed in the internal hollow cavity and includes:

[0063] A throttle valve body 131, which defines a throttle hole 131a therein;

[0064] A throttle valve seat 132, which is hollow and one end of which is connected to the throttle valve body 131 to define an internal space in the throttle valve seat 132, and the throttle valve seat 132 is provided with a valve stem holding portion 132a therein; and

[0065] A T-shaped valve stem 133 and a return spring 134 disposed in the internal space, the T-shaped valve stem 133 is held in the valve stem holding portion 132a and can slide in the valve stem holding portion to open and close the throttle hole 131a, and one end of the return spring 134 is connected to the throttle valve seat 132 and the other end is connected to the T-shaped valve stem 133 to act on the T-shaped valve stem 133 in a direction to close the throttle hole 131a.

[0066] The return spring 134 is in a compressed state under normal conditions, and the T-shaped valve stem 133 is abutted against the throttle hole 131a in the above direction by the elastic force to close it. When the pressure at the liquid inlet of the throttle hole 131a reaches a certain value (i.e., the opening pressure), the T-shaped valve stem 133 will overcome the elastic force of the return spring 134 and leave the throttle hole 131a, thereby opening the throttle hole 131a to allow the excess urea solution to be transported to flow back into the reflux component 13 from the reflux inlet end 13a via the throttle hole 131a under the action of pressure, and discharged from the reflux outlet end 13b to the liquid inlet pipeline 10a through the liquid outlet hole provided at the end of the throttle valve seat 132. Thus, the reflux of the excess urea solution transported in the pump core is realized.

[0067] Refer to Figure 7 , which shows a reflux component 13 according to another embodiment of the present disclosure, which includes:

[0068] A throttle valve body 131, which defines a throttle hole 131a therein;

[0069] A throttle valve seat 132, which is separated from the throttle valve body 131 and is provided with a valve stem holding portion 132a therein;

[0070] The T-shaped valve stem 133 is held in the valve stem holding portion 132a and can slide in the valve stem holding portion to open and close the throttle hole 131a; and

[0071] The return spring 134 has one end connected to one end of the throttle valve seat 132 and the other end connected to the T-shaped valve stem 133, and acts on the T-shaped valve stem 133 in a direction to close the throttle hole 131a by the T-shaped valve stem 133.

[0072] One end of the throttle valve seat 132 can be fixed to the internal hollow cavity. Similarly, the return spring 134 is in a compressed state under normal conditions, and the T-shaped valve stem 133 is abutted against the throttle hole 131a in the above direction by elastic force to seal it. Figure 7 The return component 13 shown in Figure 6 has the same working principle as the return component 13 shown in, and will not be elaborated here.

[0073] It is conceivable that other forms of return components can also be adopted.

[0074] According to an embodiment of the present disclosure, the return component 13 may further include a sealing seat 135. The sealing seat 135 is connected to one end of the T-shaped valve stem 133 to close the throttle hole 131a, thereby forming a fifth sealing surface A5 between it and the throttle hole 131a (see Figure 5 ).

[0075] The return component 13 may further include a filtering device such as a filter net 136. The filter net 136 can be arranged upstream of the liquid inlet of the throttle hole 131a of the throttle valve body 131 to filter the returned urea solution to be introduced into the throttle hole 131a, and avoid blockage caused by solid substances in the returned urea solution in the return component.

[0076] It is conceivable that an O-ring 137 can be arranged at the connection between the throttle valve body 131 and the integrated seat cavity 101 to achieve a sealed connection between the throttle valve body 131 and the integrated seat cavity 101.

[0077] It is conceivable that the return spring 134 can be set to contract in a direction opposite to the above direction when the pump pressure of the delivery pump component 11 reaches the calibration value, so that the T-shaped valve stem 133 opens the throttle hole 131a.

[0078] Thus, the opening pressure of the throttle hole 131a of the return component 13 can be adjusted by adjusting the working force value of the return spring 134, thereby improving the liquid suction performance of the delivery pump component 11.

[0079] In this embodiment, the calibration value of the pump pressure can be a value greater than or equal to 300 mbar.

[0080] In addition, for example, as Figure 6As shown, the liquid outlet end of the throttle hole 131a can also be configured as a small hole 131a' with a smaller aperture than that of the throttle hole 131a, and the amount of the reflux can be adjusted by adjusting the aperture of the small hole 131a'. According to an embodiment of the present disclosure, the range of the aperture of the small hole 131a' can be from 0.2 mm to 0.8 mm.

[0081] Figure 9 Fig. shows a reflux component 13 with another opening and closing mode, that is, an active opening and closing type of reflux component.

[0082] This active opening and closing type of reflux component has a structure similar to that of the reflux component shown in Figure 6 However, the T-shaped valve stem 133 is made of a material with soft magnetic properties, and an electromagnetic adsorption device 138 such as an electromagnet is provided at the end of the reflux component 13 close to the T-shaped valve stem 133, so as to, when the pump pressure of the delivery pump component 11 reaches the calibration value, for example, make the electromagnetic adsorption device 138 energized through a controller to generate a magnetic suction force on the T-shaped valve stem 133, so that the T-shaped valve stem 133 overcomes the elastic force of the return spring 134 to open the throttle hole 131a.

[0083] Next, in conjunction with Figure 5 , two working states of the pump core device 1, namely the delivery state and the back suction state, will be described.

[0084] In the delivery state, the back suction pump component 12 is closed, and the delivery diaphragm 111 of the delivery pump component 11 reciprocates up and down, and positive and negative pressures are alternately generated in the cavity 118 formed between the delivery diaphragm 111 and the delivery valve core 112.

[0085] Specifically, when the delivery diaphragm 111 moves upward, a negative pressure is generated in the cavity 118, causing the first sealing surface A1 to open and the second sealing surface A2 to close, and the urea solution enters the cavity 118 from the liquid inlet 10c through the liquid inlet pipeline 10a and the delivery liquid inlet end 11a and reaches the hole group 112a; when the delivery diaphragm 111 moves downward, a positive pressure is generated in the cavity 118, causing the first sealing surface A1 to close and the second sealing surface A2 to open, and the urea solution enters the delivery liquid outlet end 11b from the cavity 118 through the hole group 112b. A part of the urea solution enters the liquid outlet 10d through the liquid outlet pipeline 10b, and the excess urea solution passes through the filter screen 136 and passes through the throttle hole 131a under the pump pressure reaching the calibration value, and returns to the liquid inlet pipeline 10a via the fifth sealing surface A5, and is fed again through the delivery liquid inlet end 11a.

[0086] In particular, during the initial working stage of the urea pump, it is necessary to suck in the liquid and convey and compress the air inside the delivery pump component 11 to the liquid outlet pipeline 10b, ensuring that air does not enter the liquid inlet pipeline 10a through the reflux component 13 when the urea pump starts working, and avoiding the formation of an internal circulation of air inside the urea pump, thereby affecting the liquid suction performance of the pump. After working for a period of time until the pressure reaches the calibrated value, the reflux component 13 automatically opens for internal reflux.

[0087] In the back-pumping state, the delivery pump component 11 and the reflux component 13 are closed under the action of the spring, and the back-pumping diaphragm 121 of the back-pumping pump component 12 reciprocates up and down, alternately generating positive pressure and negative pressure in the cavity 124 formed between the back-pumping diaphragm 121 and the back-pumping valve plate 123.

[0088] Specifically, when the back-pumping diaphragm 121 moves downward, a negative pressure is generated in the cavity 124, causing the third sealing surface A3 to open and the fourth sealing surface A4 to close. The urea solution enters the back-pumping liquid inlet end 12a from the liquid outlet 10d through the liquid outlet pipeline 10b, and then enters the cavity 124 through the hole group 122a; when the back-pumping diaphragm 121 moves upward, a positive pressure is generated in the cavity 124, causing the third sealing surface A3 to close and the fourth sealing surface A4 to open. The urea solution enters the back-pumping liquid outlet end 12b through the hole group 122b, and then goes from the back-pumping liquid outlet end 12b through the liquid inlet pipeline 10a to the liquid inlet 10c, and is thus back-pumped into the urea solution storage tank.

[0089] As described above, it is only the specific implementation manner of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present disclosure should be covered by the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claimed rights.

Claims

1. A pump core device, characterized in that, Comprising: An integrated cavity seat, which includes a liquid inlet pipeline and a liquid outlet pipeline; A delivery pump component, which is arranged in the integrated cavity seat and includes a delivery liquid inlet end communicated with the liquid inlet pipeline and a delivery liquid outlet end communicated with the liquid outlet pipeline; A back-pumping pump component, which is arranged in the integrated cavity seat and includes a back-pumping liquid inlet end communicated with the liquid outlet pipeline and a back-pumping liquid outlet end communicated with the liquid inlet pipeline; And A reflux component, which is arranged inside the integrated cavity seat and includes a reflux liquid inlet end and a reflux liquid outlet end, wherein the reflux liquid inlet end is communicated with the liquid outlet pipeline and the reflux liquid outlet end is communicated with the liquid inlet pipeline, so as to enable the solution output from the delivery liquid outlet end to reflux to the delivery liquid inlet end, The integrated cavity seat includes a delivery pump hollow cavity for integrating the delivery pump component, a back-pumping pump hollow cavity for integrating the back-pumping pump component, and an internal hollow cavity for integrating the reflux component. Any one of the liquid inlet pipeline and the liquid outlet pipeline is communicated with the delivery pump hollow cavity, the back-pumping pump hollow cavity and the internal hollow cavity, and the internal hollow cavity is arranged between the delivery pump hollow cavity and the back-pumping pump hollow cavity.

2. The pump core device according to claim 1, wherein, The delivery pump component and the back-pumping pump component are respectively arranged at opposite ends of the integrated cavity seat.

3. The pump core device according to claim 1 or 2, characterized in that, The reflux component includes: A throttle valve body, which defines a throttle hole inside; A throttle valve seat, which is hollow and one end of which is connected to the throttle valve body to define an internal space therein, and the throttle valve seat is provided with a valve stem holding portion inside; and A T-shaped valve stem and a return spring arranged in the internal space. The T-shaped valve stem is held in the valve stem holding portion and can slide in the valve stem holding portion to open and close the throttle hole, and one end of the return spring is connected to the throttle valve seat and the other end is connected to the T-shaped valve stem, so as to act on the T-shaped valve stem in the direction of closing the throttle hole by the T-shaped valve stem.

4. The pump core device according to claim 3, characterized in that The return spring is set to contract in the direction opposite to the direction when the pump pressure of the delivery pump component reaches the calibration value, so as to enable the T-shaped valve stem to open the throttle hole.

5. The pump core device according to claim 3, characterized in that, The T-shaped valve stem is made of a material with soft magnetic properties, and an electromagnetic adsorption device is arranged at the end of the reflux component close to the T-shaped valve stem, so as to energize the electromagnetic adsorption device when the pump pressure of the delivery pump component reaches the calibration value to generate a magnetic suction force on the T-shaped valve stem, so as to enable the T-shaped valve stem to overcome the elastic force of the return spring to open the throttle hole.

6. The pump core device according to claim 3, characterized in that, The liquid outlet end of the throttle hole is configured as a small hole with a pore diameter smaller than that of the throttle hole, wherein the range of the pore diameter of the small hole is 0.2 mm to 0.8 mm.

7. The pump core device according to claim 1 or 2, characterized in that, The reflux component includes: A throttle valve body, which defines a throttle hole inside; A throttle valve seat, which is arranged separately from the throttle valve body and is provided with a valve stem holding portion inside; A T-shaped valve stem, which is held in the valve stem holding portion and can slide in the valve stem holding portion to open and close the throttle hole; and A return spring, one end of which is connected to one end of the throttle valve seat and the other end of which is connected to the T-shaped valve stem, so as to act on the T-shaped valve stem in a direction to close the throttle hole by the T-shaped valve stem.

8. A urea pump, characterized in that, It includes a pump core device according to any one of claims 1 to 7.

9. A selective catalytic reduction system, characterized in that, It includes a urea pump according to claim 8.

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