Fuel injection pump

Abstract

The fuel injection pump comprises a nozzle connecting pipe, a connecting cavity, an electromagnetic valve and a pump base, the upper portion of the pump base is connected with the nozzle connecting pipe through the connecting cavity, the electromagnetic valve is arranged on one side of the connecting cavity, a cavity is formed in the center of the pump base, a rotating shaft is sleeved with the cavity in the vertical direction, the pump base is further provided with a liquid inlet pipeline and a liquid outlet pipeline, and an outer gear is arranged at the top of the rotating shaft; a circle of inner gear is arranged on the inner wall of the cavity, the outer side of the outer gear is meshed with the inner side of the inner gear all the time and rotates along the inner gear, a crescent plate is arranged at the position where the outer gear and the inner gear are disengaged, the crescent plate is fixed in the cavity, one end of the crescent plate is a negative pressure cavity, and the other end of the crescent plate is a high pressure cavity. The oil liquid in the containing cavity is controlled by adjusting the pressure adjusting mechanism, so that the pressure of the cavity and the pipeline of the whole oil pump is controlled, the pressure at the position of the nozzle connecting pipe is guaranteed, and the sprayed oil is in a mist spray shape. The internal gear pump is adopted, so that the overall structure is compact, the gear rotating speed is high, and noise is low.

Description

Technical Field

[0001] The present invention relates to the technical field of gear pumps, and more specifically, to an oil injection pump. Background Art

[0002] The gear pump is a rotary pump that relies on the change and movement of the working volume formed between the pump cylinder and the meshing gears to transport liquid or increase its pressure. It consists of two closed spaces, two gears, a pump body, and front and rear covers. When the gears rotate, the volume of the space on the side where the gears are disengaged changes from small to large, forming a vacuum to suck in the liquid, and the volume of the space on the side where the gears are meshing changes from large to small, squeezing the liquid into the pipeline.

[0003] The internal gear pump has the advantages of simple structure, stable flow, no pulsation, and the power shaft can be coaxial with the retarder turbine shaft. In the application of fuel injection pumps, the external gear pumps currently used have low speed, high noise, and a large overall structure, resulting in low overall fuel injection efficiency. Summary of the invention

[0004] In view of this, in order to solve the above problems, the present invention proposes a fuel injection pump, which adopts an internal gear pump, so that the overall structure is compact, and the gear speed is high and the noise is low.

[0005] A fuel injection pump comprises a nozzle connecting pipe 1, a connecting chamber 2, a solenoid valve 3, and a pump seat 4. The top of the pump seat 4 is connected to the nozzle connecting pipe 1 through the connecting chamber 2. The solenoid valve 3 is arranged on one side of the connecting chamber 2. A cavity 45 is arranged at the center of the pump seat 4. A rotating shaft 41 is sleeved in the vertical direction in the cavity 45. The pump seat 4 is also provided with a liquid inlet pipe 52 and a liquid outlet pipe 7. The characteristics are as follows: an external gear 42 is arranged on the top of the rotating shaft 41, and a circle of internal gear 43 is arranged on the inner wall of the cavity 45. The outer side of the external gear 42 is always meshed with the inner side of the internal gear 43 and rotates along the internal gear 43. A crescent plate 44 is arranged at the place where the external gear 42 and the internal gear 43 are disengaged. The crescent plate 44 is fixed in the cavity 45. One end of the crescent plate 44 is a negative pressure chamber, and the other end is a high pressure chamber. The output end of the high pressure chamber is connected to a shunt channel 48, and the oil is discharged from the liquid inlet pipe. The outer gear 42 and the inner gear 43 continuously rotate and mesh with each other, pushing the oil into the high-pressure chamber of the crescent plate 44, and then flowing into the shunt channel 48 and out in two sections, one of which leads upward into the solenoid valve 3, and the other leads downward into the accommodating chamber 65 of the second chamber 6. A pressure regulating mechanism 61 is provided in the second chamber 6. When the pressure in the accommodating chamber 65 is large, the pressure regulating mechanism 61 is pushed outward, and a branch is formed on one side of the accommodating chamber 65. The branch is connected with a liquid outlet pipe 7, and the liquid outlet of the liquid outlet pipe 7 is connected to the oil tank at the liquid inlet pipe 52, so that the liquid inlet pipe 52 and the liquid outlet pipe 7 form a loop; the oil in the accommodating chamber 65 is controlled by adjusting the pressure regulating mechanism 61, thereby controlling the pressure of the chamber and pipeline of the entire oil pump to ensure the pressure at the nozzle connecting pipe 1, so that the sprayed oil presents a spray shape.

[0006] Furthermore, the tooth tip of the external gear 42 is an arc surface, which reduces the pump tip clearance, thereby increasing the sliding seal area, reducing the liquid reflux, and easily preventing internal leakage, thereby making the gear pump extremely efficient.

[0007] Furthermore, the outside of the liquid inlet pipe 52 and the liquid outlet pipe 7 are provided with markings for preventing mistakes.

[0008] Furthermore, the pump seat 4 is provided with a connecting portion 451 at the end away from the cavity 45, and a sealing ring is sleeved on the inner wall of the connecting portion 451 to make the interior of the cavity 45 vacuum-sealed. The connecting portion 451 is used to connect a motor to drive the rotating shaft 41 to rotate.

[0009] Furthermore, a reinforcing rib 452 is extended from the periphery of the connecting portion 451 , and the connecting portion 451 and the reinforcing rib 452 are integrally formed.

[0010] Furthermore, a first chamber 5 is connected between the mold cavity 45 and the liquid inlet pipe 52, and a filter structure 51 is provided inside the first chamber 5. A channel is formed between the first chamber 5 and the filter structure 51, and the input end of the channel is connected to the output end of the liquid inlet pipe 52, and the output end of the channel is connected to the input end of the mold cavity 45.

[0011] Furthermore, a first fuel injection pipe 21 and a second fuel injection pipe 25 are provided in the connecting chamber 2. The bottom of the first fuel injection pipe 21 is connected to the high-pressure chamber, and the top is connected to the liquid inlet end of the first cache tube 22. The bottom end of the second fuel injection pipe 25 is connected to the liquid inlet end of the second cache tube 24, and the top is connected to the nozzle connecting pipe 1. One end of the solenoid valve 3 is provided with a rubber plug 32. When the pressure in the pump body is small, the solenoid valve is in a closed state, and the rubber plug 32 blocks the liquid outlet ends of the first cache tube 22 and the second cache tube 24. After the oil enters the first fuel injection pipe 21, it is cached in the first cache tube 22. When the pressure is reached, the solenoid valve is opened, and the rubber plug 32 is separated from the first cache tube 22 and the second cache tube 24, so that the oil enters the second cache tube 24 from the first storage tube, flows into the second fuel injection pipe 25, and is finally sprayed out from the nozzle connecting pipe 1.

[0012] Furthermore, a transfer chamber 23 is provided on the connecting chamber 2, one end of the transfer chamber 23 is the first cache tube 22 and the second cache tube 24, and the other end is connected to the solenoid valve 3. A second spring 31 is provided in the solenoid valve 3, and one end of the second spring 31 is connected to the rubber plug 32. When the pressure is reached, the solenoid valve 3 opens to generate magnetic force, so that the second spring 31 is sucked inward, pulling the rubber plug 32 out of the first cache tube 22 and the second cache tube 24, and the oil enters the transfer chamber 23 from the first cache tube 22, and then enters the second cache tube 24. When the solenoid valve 3 is closed, the magnetic force disappears, the second spring 31 loses its force and returns to its original state, pushing the rubber plug 32 to block the first cache tube 22 and the second cache tube 24.

[0013] Beneficial effects of the present invention: The present invention proposes a fuel injection pump, comprising a nozzle connecting pipe 1, a connecting chamber 2, a solenoid valve 3, and a pump seat 4. The top of the pump seat 4 is connected to the nozzle connecting pipe 1 through the connecting chamber 2, and the solenoid valve 3 is arranged on one side of the connecting chamber 2. A cavity 45 is arranged at the center of the pump seat 4, and a rotating shaft 41 is sleeved in the vertical direction of the cavity 45. The pump seat 4 is also provided with a liquid inlet pipe 52 and a liquid outlet pipe 7. An external gear 42 is arranged on the top of the rotating shaft 41, and a circle of internal gears 43 are arranged on the inner wall of the cavity 45. The outer side of the external gear 42 is always meshed with the inner side of the internal gear 43 and rotates along the internal gear 43. A crescent plate 44 is arranged at the place where the external gear 42 and the internal gear 43 are disengaged, and the crescent plate 44 is fixed in the cavity 45. One end of the crescent plate 44 is a negative pressure chamber, and the other end is a high pressure chamber. The output end of the high pressure chamber is connected to the diversion channel 48, and the oil flows from the liquid inlet pipe 52 into the crescent plate 44. Negative pressure chamber, the outer gear 42 and the inner gear 43 rotate and mesh continuously, pushing the oil into the high-pressure chamber of the crescent plate 44, and then flowing into the diversion channel 48 and outflowing in two sections, one section of which leads upward into the solenoid valve 3, and the other section leads downward into the accommodating chamber 65 of the second chamber 6. The second chamber 6 is provided with a pressure regulating mechanism 61. When the pressure in the accommodating chamber 65 is large, the pressure regulating mechanism 61 is pushed outward, and a branch is formed on one side of the accommodating chamber 65. The branch is connected with a liquid outlet pipe 7, and the liquid outlet of the liquid outlet pipe 7 is connected to the oil tank at the liquid inlet pipe 52, so that the liquid inlet pipe 52 and the liquid outlet pipe 7 form a loop; the oil in the accommodating chamber 65 is controlled by adjusting the pressure regulating mechanism 61, thereby controlling the pressure of the chamber and pipeline of the entire oil pump to ensure the pressure at the nozzle connecting pipe 1, so that the sprayed oil is in a spray shape; the use of an internal meshing gear pump makes the overall structure compact, and at the same time the gear speed is high and the noise is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is the overall structural diagram of the fuel injection pump of the present invention.

[0015] Figure 2 It is a cross-sectional view of the pump seat of the fuel injection pump of the present invention.

[0016] Figure 3 Structural diagram of the pump seat of the fuel injection pump of the present invention.

[0017] Figure 4 Structural diagram of the pump seat of the fuel injection pump of the present invention.

[0018] Figure 5 An overall cross-sectional view of the fuel injection pump of the present invention.

[0019] Figure 6 A schematic diagram of the connection between the first chamber and the second chamber of the fuel injection pump of the present invention.

[0020] Figure 7A cross-sectional view showing the connection between the first chamber and the second chamber of the fuel injection pump of the present invention.

[0021] Figure 8 Structural diagram of the connecting chamber of the fuel injection pump of the present invention.

[0022] Fig. 9 A cross-sectional view of the solenoid valve chamber of the fuel injection pump of the present invention.

[0023] Fig.10 A cross-sectional view of the connection of the solenoid valve chamber of the fuel injection pump of the invention.

[0024] Main component symbols

[0025] Nozzle connecting pipe 1, connecting chamber 2, first fuel injection pipe 21, first cache pipe 22, transfer chamber 23, second cache pipe 24, second fuel injection pipe 25, solenoid valve 3, second spring 31, rubber plug 32, pump seat 4, rotating shaft 41, external gear 42, internal gear 43, crescent plate 44, cavity 45, connecting part 451, reinforcing rib 452, liquid inlet channel 46, diversion channel 48, first chamber 5, filter structure 51, liquid inlet pipeline 52, rear cover 53, second chamber 6, pressure regulating mechanism 61, accommodating chamber 65, liquid outlet pipeline 7.

[0026] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0027] Embodiment 1:

[0028] A fuel injection pump comprises a nozzle connecting pipe 1, a connecting chamber 2, a solenoid valve 3, and a pump seat 4. The top of the pump seat 4 is connected to the nozzle connecting pipe 1 through the connecting chamber 2. The solenoid valve 3 is arranged on one side of the connecting chamber 2. A cavity 45 is arranged at the center of the pump seat 4. A rotating shaft 41 is sleeved in the vertical direction in the cavity 45. The pump seat 4 is also provided with a liquid inlet pipe 52 and a liquid outlet pipe 7. The characteristics are as follows: an external gear 42 is arranged on the top of the rotating shaft 41, and a circle of internal gear 43 is arranged on the inner wall of the cavity 45. The outer side of the external gear 42 is always meshed with the inner side of the internal gear 43 and rotates along the internal gear 43. A crescent plate 44 is arranged at the place where the external gear 42 and the internal gear 43 are disengaged. The crescent plate 44 is fixed in the cavity 45. One end of the crescent plate 44 is a negative pressure chamber, and the other end is a high pressure chamber. The output end of the high pressure chamber is connected to a shunt channel 48, and the oil is discharged from the liquid inlet pipe. The outer gear 42 and the inner gear 43 continuously rotate and mesh with each other, pushing the oil into the high-pressure chamber of the crescent plate 44, and then flowing into the shunt channel 48 and out in two sections, one of which leads upward into the solenoid valve 3, and the other leads downward into the accommodating chamber 65 of the second chamber 6. A pressure regulating mechanism 61 is provided in the second chamber 6. When the pressure in the accommodating chamber 65 is large, the pressure regulating mechanism 61 is pushed outward, and a branch is formed on one side of the accommodating chamber 65. The branch is connected with a liquid outlet pipe 7, and the liquid outlet of the liquid outlet pipe 7 is connected to the oil tank at the liquid inlet pipe 52, so that the liquid inlet pipe 52 and the liquid outlet pipe 7 form a loop; the oil in the accommodating chamber 65 is controlled by adjusting the pressure regulating mechanism 61, thereby controlling the pressure of the chamber and pipeline of the entire oil pump to ensure the pressure at the nozzle connecting pipe 1, so that the sprayed oil presents a spray shape.

[0029] The tooth tip of the external gear 42 is an arc surface, which reduces the pump tip clearance, thereby increasing the sliding seal area, reducing the liquid reflux, and easily preventing internal leakage, thereby making the gear pump extremely efficient.

[0030] The outside of the liquid inlet pipe 52 and the liquid outlet pipe 7 are provided with markings for foolproofing.

[0031] The pump seat 4 is provided with a connecting portion 451 at the end away from the cavity 45. The inner wall of the connecting portion 451 is sleeved with a sealing ring to make the interior of the cavity 45 in a vacuum sealed state. The connecting portion 451 is used to connect a motor to drive the rotating shaft 41 to rotate.

[0032] A reinforcing rib 452 is extended from the periphery of the connecting portion 451 , and the connecting portion 451 and the reinforcing rib 452 are integrally formed.

[0033] A first chamber 5 is connected between the mold cavity 45 and the liquid inlet pipe 52, and a filter structure 51 is provided inside the first chamber 5. A channel is formed between the first chamber 5 and the filter structure 51, and the input end of the channel is connected to the output end of the liquid inlet pipe 52, and the output end of the channel is communicated with the input end of the mold cavity 45.

[0034] A first fuel injection pipe 21 and a second fuel injection pipe 25 are provided in the connecting chamber 2. The bottom of the first fuel injection pipe 21 is connected to the high-pressure chamber, and the top is connected to the liquid inlet end of the first cache tube 22. The bottom end of the second fuel injection pipe 25 is connected to the liquid inlet end of the second cache tube 24, and the top is connected to the nozzle connecting pipe 1. One end of the solenoid valve 3 is provided with a rubber plug 32. When the pressure in the pump body is small, the solenoid valve is in a closed state, and the rubber plug 32 blocks the liquid outlet ends of the first cache tube 22 and the second cache tube 24. The oil enters the first fuel injection pipe 21 and is cached in the first cache tube 22. When the pressure is reached, the solenoid valve is opened, and the rubber plug 32 is separated from the first cache tube 22 and the second cache tube 24, so that the oil enters the second cache tube 24 from the first storage tube, flows into the second fuel injection pipe 25, and is finally sprayed out from the nozzle connecting pipe 1.

[0035] A transfer chamber 23 is provided on the connecting chamber 2, one end of the transfer chamber 23 is the first cache tube 22 and the second cache tube 24, and the other end is connected to the solenoid valve 3. A second spring 31 is provided in the solenoid valve 3, and one end of the second spring 31 is connected to the rubber plug 32. When the pressure is reached, the solenoid valve 3 opens to generate magnetic force, so that the second spring 31 is sucked inward, pulling the rubber plug 32 out of the first cache tube 22 and the second cache tube 24, and the oil enters the transfer chamber 23 from the first cache tube 22, and then enters the second cache tube 24. When the solenoid valve 3 is closed, the magnetic force disappears, the second spring 31 loses its force and returns to its original state, pushing the rubber plug 32 to block the first cache tube 22 and the second cache tube 24.

[0036] Beneficial effects of the present invention: The present invention proposes a fuel injection pump, comprising a nozzle connecting pipe 1, a connecting chamber 2, a solenoid valve 3, and a pump seat 4. The top of the pump seat 4 is connected to the nozzle connecting pipe 1 through the connecting chamber 2, and the solenoid valve 3 is arranged on one side of the connecting chamber 2. A cavity 45 is arranged at the center of the pump seat 4, and a rotating shaft 41 is sleeved in the vertical direction of the cavity 45. The pump seat 4 is also provided with a liquid inlet pipe 52 and a liquid outlet pipe 7. An external gear 42 is arranged on the top of the rotating shaft 41, and a circle of internal gears 43 are arranged on the inner wall of the cavity 45. The outer side of the external gear 42 is always meshed with the inner side of the internal gear 43 and rotates along the internal gear 43. A crescent plate 44 is arranged at the place where the external gear 42 and the internal gear 43 are disengaged, and the crescent plate 44 is fixed in the cavity 45. One end of the crescent plate 44 is a negative pressure chamber, and the other end is a high pressure chamber. The output end of the high pressure chamber is connected to the diversion channel 48, and the oil flows from the liquid inlet pipe 52 into the crescent plate 44. Negative pressure chamber, the outer gear 42 and the inner gear 43 rotate and mesh continuously, pushing the oil into the high-pressure chamber of the crescent plate 44, and then flowing into the diversion channel 48 and outflowing in two sections, one section of which leads upward into the solenoid valve 3, and the other section leads downward into the accommodating chamber 65 of the second chamber 6. The second chamber 6 is provided with a pressure regulating mechanism 61. When the pressure in the accommodating chamber 65 is large, the pressure regulating mechanism 61 is pushed outward, and a branch is formed on one side of the accommodating chamber 65. The branch is connected with a liquid outlet pipe 7, and the liquid outlet of the liquid outlet pipe 7 is connected to the oil tank at the liquid inlet pipe 52, so that the liquid inlet pipe 52 and the liquid outlet pipe 7 form a loop; the oil in the accommodating chamber 65 is controlled by adjusting the pressure regulating mechanism 61, thereby controlling the pressure of the chamber and pipeline of the entire oil pump to ensure the pressure at the nozzle connecting pipe 1, so that the sprayed oil is in a spray shape; the use of an internal meshing gear pump makes the overall structure compact, and at the same time the gear speed is high and the noise is low.

[0037] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A fuel injection pump, comprising a nozzle connecting pipe (1), a connecting chamber (2), a solenoid valve (3), and a pump seat (4), wherein the upper portion of the pump seat (4) is connected to the nozzle connecting pipe (1) via the connecting chamber (2), the solenoid valve (3) is arranged on one side of the connecting chamber (2), a cavity (45) is arranged at the center of the pump seat (4), a rotating shaft (41) is sleeved in the vertical direction of the cavity (45), the pump seat (4) is further provided with a liquid inlet pipe (52) and a liquid outlet pipe (7), characterized in that: An external gear (42) is provided on the top of the rotating shaft (41), and a circle of internal gears (43) is provided on the inner wall of the cavity (45). The outer side of the external gear (42) is always meshed with the inner side of the internal gear (43) and rotates along the internal gear (43). A crescent plate (44) is provided at the place where the external gear (42) and the internal gear (43) are disengaged. The crescent plate (44) is fixed in the cavity (45). One end of the crescent plate (44) is a negative pressure cavity, and the other end is a high pressure cavity. The output end of the high pressure cavity is connected to the shunt channel (48). Oil flows from the liquid inlet pipe (52) into the negative pressure cavity of the crescent plate (44). The external gear (42) and the internal gear (43) are continuously rotated and meshed, pushing the oil into the high pressure cavity of the crescent plate (44), and then flows into the shunt channel (48) in two sections. The liquid flows out, one section of which flows upward into the solenoid valve (3), and the other section flows downward into the accommodating chamber (65) of the second chamber (6). The second chamber (6) is provided with a pressure regulating mechanism (61). When the pressure in the accommodating chamber (65) is high, the pressure regulating mechanism (61) is pushed outward. A branch is formed on one side of the accommodating chamber (65). The branch is connected to a liquid outlet pipe (7). The liquid outlet of the liquid outlet pipe (7) is connected to the oil tank at the liquid inlet pipe (52), so that the liquid inlet pipe (52) and the liquid outlet pipe (7) form a loop. The oil in the accommodating chamber (65) is controlled by adjusting the pressure regulating mechanism (61), thereby controlling the pressure of the chamber and pipeline of the entire oil pump to ensure the pressure at the nozzle connecting pipe (1), so that the sprayed oil appears in a spray shape.

2. The fuel injection pump according to claim 1, characterized in that: The tooth tip of the external gear (42) is an arc surface, which reduces the pump tip clearance, thereby increasing the sliding seal area, reducing the liquid reflux, and easily preventing internal leakage, thereby making the gear pump extremely efficient.

3. The fuel injection pump according to claim 1, characterized in that: The outside of the liquid inlet pipe (52) and the liquid outlet pipe (7) are provided with markings for preventing mistakes.

4. The fuel injection pump according to claim 1, characterized in that: The pump seat (4) is provided with a connecting portion (451) at the end away from the cavity (45), and a sealing ring is sleeved on the inner wall of the connecting portion (451), so that the interior of the cavity (45) is in a vacuum sealed state. The connecting portion (451) is used to connect to a motor, and the motor drives the rotating shaft (41) to rotate.

5. The fuel injection pump according to claim 1, characterized in that: A reinforcing rib (452) is extended from the periphery of the connecting portion (451), and the connecting portion (451) and the reinforcing rib (452) are integrally formed.

6. The fuel injection pump according to claim 1, characterized in that: A first chamber (5) is connected between the mold cavity (45) and the liquid inlet pipe (52), a filter structure (51) is sleeved in the first chamber (5), a channel is formed between the first chamber (5) and the filter structure (51), the input end of the channel is connected to the output end of the liquid inlet pipe (52), and the output end of the channel is communicated with the input end of the mold cavity (45).

7. The fuel injection pump according to claim 1, characterized in that: A first fuel injection pipe (21) and a second fuel injection pipe (25) are provided in the connecting chamber (2). The bottom of the first fuel injection pipe (21) is connected to the high-pressure chamber, and the top is connected to the liquid inlet end of the first buffer tube (22). The bottom end of the second fuel injection pipe (25) is connected to the liquid inlet end of the second buffer tube (24), and the top is connected to the nozzle connecting pipe (1). One end of the solenoid valve (3) is provided with a rubber plug (32). When the pressure in the pump body is low, the solenoid valve is in a closed state. The rubber plug (32) blocks the liquid outlet ends of the first buffer tube (22) and the second buffer tube (24). After the oil enters the first fuel injection pipe (21), it is buffered in the first buffer tube (22). When the pressure reaches a certain level, the solenoid valve is opened, and the rubber plug (32) is separated from the first buffer tube (22) and the second buffer tube (24), so that the oil enters the second buffer tube (24) from the first buffer tube, flows into the second fuel injection pipe (25), and finally is sprayed out from the nozzle connecting pipe (1).

8. The fuel injection pump according to claim 1, characterized in that: The connecting chamber (2) is provided with a transfer chamber (23), one end of the transfer chamber (23) is the first cache tube (22) and the second cache tube (24), and the other end is connected to the solenoid valve (3), a second spring (31) is provided in the solenoid valve (3), one end of the second spring (31) is connected to the rubber plug (32), when the pressure reaches a certain level, the solenoid valve (3) opens to generate magnetic force, so that the second spring (31) is sucked inward, pulling the rubber plug (32) out of the first cache tube (22) and the second cache tube (24), the oil enters the transfer chamber (23) from the first cache tube (22), and then enters the second cache tube (24). When the solenoid valve (3) is closed, the magnetic force disappears, the second spring (31) loses its force and returns to its original state, pushing the rubber plug (32) to block the first cache tube (22) and the second cache tube (24).

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