A differential pressure signal device

Abstract

This invention discloses a differential pressure signal device, comprising a housing, a piston assembly, and a signal cap assembly. The housing has a first magnetic element, the piston assembly has a second magnetic element, and the signal cap assembly has a third magnetic element. The piston assembly is slidably disposed within a chamber on the housing. A low-pressure port and a high-pressure port on the housing are connected to the chamber. The signal cap assembly is slidably disposed on the housing and located outside the chamber. A first elastic element is provided between the housing and the piston assembly to drive the piston assembly to isolate the low-pressure port from the high-pressure port and move it away from the signal cap assembly. Under normal differential pressure conditions, the signal cap assembly is held in its normal position by the first magnetic element. When the differential pressure reaches a preset value, the piston assembly moves closer to the signal cap assembly, and the second magnetic element drives the signal cap assembly to the indicated position. This invention uses magnetic force for safety locking. In case of abnormal differential pressure, the signal cap assembly is mechanically activated by magnetic force, resulting in high trigger reliability, good accuracy, and good protection.

Description

Technical Field

[0001] This invention relates to the field of pressure signal device technology, and more particularly to a differential pressure signal device. Background Technology

[0002] Differential pressure signalers are commonly used in fuel systems. Common differential pressure sensors typically employ a mechanical valve assembly structure to sense pressure. When the differential pressure is below the indicated value, the signaler does not activate; when the differential pressure reaches or exceeds the indicated value, the signaler activates to provide an indication. One existing type of traditional differential pressure signaler is... Figure 1 As shown, when the fuel pressure differential is at a normal value, the small magnet in the signal cap assembly 1 and the large magnet in the valve assembly 2 attract each other, thus keeping the signal cap assembly locked. When the fuel pressure differential reaches the indicated value, the pressure difference is greater than the magnetic attraction between the small and large magnets. The fuel pressure will push the valve assembly 2 to compress the large spring 3 away from the signal cap assembly 1. At this time, the magnetic attraction between the small and large magnets decreases, and the signal cap assembly 1 pops out under the elastic force of the small spring, achieving the purpose of alarm indication. Furthermore, the valve assembly 2 moves to the right low-pressure chamber 5 under the action of the fuel pressure in the high-pressure chamber 4. When the fuel pressure differential increases to a preset value, the high and low pressure chambers are connected to protect the equipment in the high-pressure chamber. However, the existing differential pressure signal device cannot be used in application scenarios where the positions of the high-pressure chamber and the low-pressure chamber are interchanged. The valve assembly can only move from the high-pressure chamber to the low-pressure chamber and cannot reliably trigger the signal cap assembly to perform the indication action. Summary of the Invention

[0003] The technical problem to be solved and the technical task proposed by the present invention is to improve the existing technology and provide a differential pressure signal device to solve the problem that the existing differential pressure signal devices in the current technology cannot be applied to application scenarios where the positions of the high pressure chamber and the low pressure chamber are interchanged, and cannot reliably trigger the signal cap to perform the indication action.

[0004] To solve the above technical problems, the technical solution of the present invention is as follows:

[0005] A differential pressure signal device includes a housing, a piston assembly, and a signal cap assembly. A first magnetic element is disposed on the housing, a second magnetic element is disposed on the piston assembly, and a third magnetic element is disposed on the signal cap assembly. The piston assembly is slidably disposed in a chamber disposed on the housing. The housing has a low-pressure port and a high-pressure port communicating with the chamber. The signal cap assembly is slidably disposed on the housing and located outside the chamber. A first elastic element is disposed between the housing and the piston assembly, the first elastic element being used to drive the piston assembly to a position that isolates the low-pressure port from the high-pressure port and moves it away from the signal cap assembly.

[0006] When the pressure difference between the low-pressure port and the high-pressure port is less than a preset value, the signal cap assembly remains in the normal position under the magnetic force generated by the first magnetic element on the third magnetic element. When the pressure difference between the low-pressure port and the high-pressure port reaches the preset value, the piston assembly moves closer to the signal cap assembly against the force of the first elastic element, and the magnetic force generated by the second magnetic element on the third magnetic element drives the signal cap assembly to move to the indicator position.

[0007] When the differential pressure signal device of the present invention is in a normal state, the signal cap assembly is magnetically attracted to the normal state position. At this time, the magnetic force of the first magnetic element on the third magnetic element is greater than the magnetic force of the second magnetic element on the third magnetic element, thereby ensuring that the signal cap assembly is reliably and stably in the normal state position and avoiding false alarms. When the differential pressure increases to a preset value of one or more, the piston assembly moves closer to the signal cap assembly. The magnetic force of the second magnetic element on the third magnetic element increases and exceeds the magnetic force of the first magnetic element on the third magnetic element, thereby pushing the third magnetic element to move, that is, pushing the signal cap assembly to slide, so that the signal cap assembly switches to the indicator position to realize mechanical alarm. When the differential pressure decreases and returns to the normal range, the piston assembly will move away from the signal cap assembly and reset under the action of the first elastic element. The magnetic force of the second magnetic element on the third magnetic element decreases, so the signal cap assembly will reset to the normal state position under the magnetic force of the first magnetic element on the third magnetic element to deactivate the mechanical alarm. This is suitable for application scenarios where the positions of the high pressure chamber and the low pressure chamber are interchanged.

[0008] Furthermore, one of the first and third magnetic components is a ring magnet, and the other is a cylindrical magnet. The ring magnet is fitted around the circumference of the cylindrical magnet. The magnetic poles of the first and third magnetic components are in the same direction and along the sliding direction of the signal cap assembly. The magnetic poles of the second magnetic component are opposite to those of the first magnetic component. This design is compact, occupies little space, and allows the first and second magnetic components to fully interact with the third magnetic component, thereby enabling the signal cap assembly to move as the second magnetic component moves with the piston assembly.

[0009] Furthermore, the second magnetic component is an annular magnetic component, which is slidably mounted on a guide post disposed on the inner wall of the chamber along the sliding direction of the piston assembly. This serves to limit and guide the second magnetic component, ensuring the stability of the magnetic force between the second and third magnetic components. This ensures that the third magnetic component can move reliably under the drive of the second magnetic component, which in turn ensures that the signal cap assembly can move reliably for mechanical warning.

[0010] Furthermore, the piston assembly includes a piston body and a movable part. The second magnetic element is connected to the movable part, which is slidably connected to the piston body. The sliding direction of the movable part is along the sliding direction of the piston assembly in the chamber. A second elastic element is provided between the movable part and the piston body to drive the movable part to extend towards the side where the signal cap assembly is located. Due to the limited magnetic force application distance, the sliding stroke of the signal cap assembly is small, while the piston assembly requires a large stroke. A structure is adopted to allow the low-pressure chamber and high-pressure chamber to conduct to their maximum opening. Therefore, the strokes of the signal cap assembly and the piston assembly do not match. A structure in which the second magnetic element is elastically connected to the piston body is used to match the different strokes, satisfying the requirement of limited magnetic force application distance to ensure reliable triggering of the signal cap assembly, while also allowing the piston body to have a large stroke to meet the opening requirements.

[0011] Furthermore, when the movable part does not touch the inner wall of the chamber, the second elastic element exerts a pre-force on the movable part. This pre-force is greater than the magnetic force exerted by the first magnetic element on the third magnetic element when the signal cap assembly is in its normal position. This ensures that when the piston assembly moves towards the signal cap assembly, the second magnetic element can effectively push the signal cap assembly towards the indicator position. It prevents the second elastic element from exerting too little force on the movable part, which could cause the signal cap assembly to fail to move, resulting in the force between the second and third elastic elements pushing the movable part in the opposite direction, compressing the second elastic element and causing it to slide. In other words, too little force from the second elastic element on the movable part could prevent the signal cap assembly from moving for mechanical warning, or could lead to a deviation in triggering accuracy.

[0012] Furthermore, the movable part is slidably sleeved on the screw that is screwed to the piston body. The screw extends out of the piston body for turning and adjusting the screw, thereby adjusting the pre-force of the second elastic element on the movable part. The structure is compact and easy to adjust, ensuring that the signal cap assembly can be reliably and accurately triggered to operate.

[0013] Furthermore, when the pressure difference reaches the preset value, the inner wall of the bottom-touching chamber of the moving part is at the same time there is no relative displacement between the moving part and the piston body, and the high-pressure chamber and the low-pressure chamber are partially connected.

[0014] When the pressure difference continues to increase to the preset value of two, the relative displacement between the moving part and the piston body reaches its maximum, and the high-pressure chamber and the low-pressure chamber are fully connected.

[0015] When the pressure difference reaches a preset value, the signal cap assembly activates to provide a mechanical warning. When the pressure difference further reaches the preset value, the high-pressure chamber port and the low-pressure chamber port are connected to the maximum opening, allowing the high-pressure fuel in the high-pressure chamber to be released into the low-pressure chamber. This effectively prevents damage to the equipment in the high-pressure chamber and improves protection.

[0016] Furthermore, the piston body has a perforated hole. When the pressure difference between the low-pressure chamber and the high-pressure chamber is less than a preset value of two, the low-pressure chamber is connected to the area of ​​the chamber near the signal cap assembly through the perforated hole. Fuel in the area of ​​the chamber near the signal cap assembly can be discharged into the low-pressure chamber along the path from the perforated hole to the low-pressure chamber, ensuring that the piston body can slide effectively.

[0017] Furthermore, the housing includes a first housing component and a second housing component. The first housing component is cylindrical, and its interior forms the chamber. The second housing component is sealed to one end of the first housing component. The first magnetic component is disposed on the second housing component, and the signal cap assembly is slidably connected to the second housing component. The structure is simple, easy to implement, and convenient to assemble and disassemble.

[0018] Furthermore, the signal cap assembly is slidably mounted on the column provided on the second housing, and an end cap is fixed on the second housing by a retaining ring. The end cap limits the signal cap assembly, ensuring that the signal cap assembly slides accurately and stably for mechanical warning.

[0019] Compared with the prior art, the advantages of this invention are:

[0020] The differential pressure signal device described in this invention uses magnetic force for safety locking. When the differential pressure is abnormal, the signal cap assembly is pushed out by magnetic force to provide a mechanical warning. The movement stroke of the signal cap assembly is matched with the movement stroke of the piston assembly, resulting in high reliability and accuracy of the warning trigger. It also provides good protection for the equipment in the high-pressure chamber and is suitable for application scenarios where the positions of the high-pressure chamber and the low-pressure chamber are interchanged. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of an existing differential pressure signaler.

[0022] Figure 2 This is a schematic diagram of the differential pressure signal device of the present invention when the differential pressure is within the normal range;

[0023] Figure 3 This is a schematic diagram of the differential pressure signal device of the present invention when the differential pressure reaches a preset value.

[0024] Figure 4 This is a schematic diagram of the differential pressure signal device of the present invention when the differential pressure reaches a preset value of two.

[0025] In the picture:

[0026] Housing 1, Chamber 11, Low-pressure port 12, High-pressure port 13, Housing component 14, Housing component 2 15, End cap 16, Guide post 17, Piston assembly 2, Piston body 21, Hollow hole 211, Movable part 22, Second elastic component 23, Screw 24, Signal cap assembly 3, First elastic component 4, First magnetic component 51, Second magnetic component 52, Third magnetic component 53. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] The differential pressure signal device disclosed in this invention has a simple and compact structure and is suitable for application scenarios where the positions of the high-pressure chamber and the low-pressure chamber are interchanged. The piston assembly moves to the side where the signal cap assembly is located to trigger the signal cap assembly to perform an indication action. Furthermore, when the fuel pressure differential increases to a preset value, it can connect the high-pressure chamber and the low-pressure chamber to achieve the purpose of protecting the equipment in the high-pressure chamber.

[0029] like Figures 2 to 4 As shown, a differential pressure signal device mainly includes a housing 1, a piston assembly 2, and a signal cap assembly 3. The housing 1 is provided with a first magnetic element 51, the piston assembly 2 is provided with a second magnetic element 52, and the signal cap assembly 3 is provided with a third magnetic element 53. The piston assembly 2 is slidably disposed in a chamber 11 provided on the housing 1. The housing 1 is provided with a low-pressure port 12 and a high-pressure port 13 communicating with the chamber 11. The signal cap assembly 3 is slidably disposed on the housing 1 and located outside the chamber 11. A first elastic element 4 is provided between the housing 1 and the piston assembly 2. The first elastic element 4 is used to drive the piston assembly 2 to a position that isolates the low-pressure port 12 from the high-pressure port 13 and moves it away from the signal cap assembly 3.

[0030] When the pressure difference between the low-pressure port 12 and the high-pressure port 13 is less than a preset value, the signal cap assembly 3 remains in the normal position under the magnetic force generated by the first magnetic element 51 on the third magnetic element 53. When the pressure difference between the low-pressure port 12 and the high-pressure port 13 reaches the preset value, the piston assembly 2 moves closer to the signal cap assembly 3 against the force of the first elastic element 4, and the magnetic force generated by the second magnetic element 52 on the third magnetic element 53 drives the signal cap assembly 3 to move to the indicator position.

[0031] Specifically, the housing 1 includes a first housing part 14 and a second housing part 15. The first housing part 14 is cylindrical, and its interior constitutes the chamber 11. The piston assembly 2 is slidably disposed in the chamber 11 along the axial direction of the first housing part 14. The second housing part 15 is sealed to the left end of the first housing part 14 along its axial direction. The housing 1 and the piston assembly 2 together form a piston cylinder structure. The right end opening of the first housing part 14 along its axial direction is the high-pressure port 13 for connecting to the high-pressure chamber, while holes are opened on the side wall of the first housing part 14 to form a low-pressure port 12 for connecting to the low-pressure chamber. The first magnetic element 51 is disposed on the second housing part 15, and the signal cap assembly 3... The signal cap assembly 3 is slidably connected to the housing 15, that is, the signal cap assembly 3 is located on the end side of the piston assembly 2 in the sliding direction. The sliding direction of the signal cap assembly 3 on the housing 15 is along the sliding direction of the piston assembly 2. Specifically, the signal cap assembly 3 is slidably fitted onto the column provided on the left side of the housing 15. The length direction of the column is along the sliding direction of the piston assembly 2. An end cap 16 is fixed on the housing 15 by a retaining ring. The end cap 16 is used to limit the signal cap assembly 3. The end cap 16 is used to limit the maximum position of the signal cap assembly 3 sliding to the left. The end cap 16 has an opening to allow the signal cap assembly 3 to slide to the left and pop out to the indicator position.In this embodiment, the first elastic element 4 is a spring installed in the chamber 11. The spring is located between the second shell 15 and the piston assembly 2. The spring drives the piston assembly 2 away from the second shell 15 (that is, away from the signal cap assembly 3). When the pressure difference is within the normal range, the piston assembly 2 is at the rightmost end of the first shell 14 under the action of the first elastic element 4. At this time, the distance between the signal cap assembly 3 and the piston assembly 2 is large, that is, the distance between the second magnetic element 52 and the third magnetic element 53 is large. Therefore, the magnetic force generated by the first magnetic element 51 on the third magnetic element 53 is greater than the magnetic force generated by the second magnetic element 52 on the third magnetic element 53. Consequently, the signal cap assembly 3 is at the rightmost end (normal state position) in the sliding direction of the signal cap assembly 3 under the action of the first magnetic element 51. That is, the signal cap assembly 3 abuts against the second shell 15 to the right to be in the position closest to the chamber 11. When the pressure difference is abnormal and reaches a preset value, the piston assembly 2... Due to the pressure difference, component 2 is pushed to the left end of the shell component 14. The piston assembly 2 overcomes the elastic force of the first elastic component 4, causing the first elastic component 4 to compress and deform, accumulating elastic potential energy. At this time, the distance between the piston assembly 2 and the signal cap assembly 3 decreases, that is, the distance between the second magnetic component 52 and the third magnetic component 53 decreases. As a result, the magnetic force generated by the second magnetic component 52 on the third magnetic component 53 increases, and the magnetic force generated by the second magnetic component 52 on the third magnetic component 53 increases to a level greater than the magnetic force generated by the first magnetic component 51 on the third magnetic component 53. Thus, the magnetic force generated by the second magnetic component 52 on the third magnetic component 53 can drive the third magnetic component 53 to move to the left relative to the first magnetic component 51. That is, the signal cap assembly 3 slides to the left and pops out to the indicator position under the action of the second magnetic component 52, realizing mechanical warning. The differential pressure signal device described in this embodiment has high structural stability and high operational reliability.

[0032] The magnetic force generated by the first magnetic element 51 on the third magnetic element 53 is opposite to the magnetic force generated by the second magnetic element 52 on the third magnetic element 53. The magnetic force generated by the first magnetic element 51 on the third magnetic element 53 is to the right so that the signal cap assembly 3 is locked in the normal state position within the normal pressure difference range or moves to the right from the indicator position to reset to the normal state position. The magnetic force generated by the second magnetic element 52 on the third magnetic element 53 is to the left. When the pressure difference reaches a preset value of one or more, the magnetic force generated by the second magnetic element 52 on the third magnetic element 53 drives the signal cap assembly 3 to move to the left to the indicator position. In this embodiment, the first magnetic element 51 is a cylindrical magnet, and the third magnetic element 53 is a ring magnet. The third magnetic element 53 is encircled around the circumference of the first magnetic element 51. The first magnetic element 51 is specifically disposed in a column disposed on the left side of the housing 15, and the third magnetic element 53 is encircled around the column so as to slide along the axial direction of the column. The magnetic poles of the first magnetic element 51 and the third magnetic element 53 are in the same direction and along the sliding direction of the signal cap assembly 3. For example, the right end of the first magnetic element 51 is S-pole and the left end is N-pole, and the right end of the third magnetic element 53 is also S-pole and the left end is also N-pole. Since the third magnetic element 53 is encircled around the circumference of the first magnetic element 51, the magnetic force generated by the first magnetic element 51 on the third magnetic element 53 is... The direction is to the right, causing the signal cap assembly 3 to abut against the housing 15 to lock in the normal position. The magnetic pole direction of the second magnetic element 52 is opposite to that of the first magnetic element 51, that is, the right end of the second magnetic element 52 is N-pole and the left end is S-pole. Therefore, the magnetic force generated by the second magnetic element 52 on the third magnetic element 53 is to the left. When the piston assembly 2 moves to the left and approaches the signal cap assembly 3, the magnetic force generated by the second magnetic element 52 on the third magnetic element 53 gradually increases and increases to a level greater than the magnetic force generated by the first magnetic element 51 on the third magnetic element 53 when the signal cap assembly 3 is in the normal position. Thus, the second magnetic element 52 can push the third magnetic element 53 to move to the left to move away from the second magnetic element 52, that is, drive the signal cap assembly 3 to slide to the left to the indicator position. Since the third magnetic element 53 is a ring magnet surrounding the first magnetic element 51, when the signal cap assembly 3 is in the normal position, the right end face of the third magnetic element 53 is approximately flush with the right end face of the first magnetic element 51. This allows the second magnetic element 52 to approach the third magnetic element 53 more fully, generating a sufficiently large magnetic force between them to drive the third magnetic element 53 to move relative to the first magnetic element 51.

[0033] In this embodiment, the second magnetic element 52 is specifically an annular magnetic element, which can better generate magnetic force on the second magnetic element 52. Furthermore, the wall surface of the shell 15 facing the cavity 11 is provided with a guide post 17 along the sliding direction of the piston assembly 2. The second magnetic element 52 is slidably sleeved on the guide post 17, which plays a limiting and guiding role for the second magnetic element 52, ensuring the stability of the magnetic force between the second magnetic element 52 and the third magnetic element 53, thereby reliably triggering the signal cap assembly 3 to operate.

[0034] The magnetic force has a limited range, meaning that the second magnetic element 52 needs to be at a relatively close position to generate a sufficiently large magnetic force on the third magnetic element 53. Furthermore, the signal cap assembly 3 also utilizes the magnetic force generated by the first magnetic element 51 on the third magnetic element 53 to reset from the indicator position to the normal state position. Therefore, the movement stroke of the signal cap assembly 3 cannot be too large. The differential pressure signal device not only needs to provide mechanical warning, but also needs to fully conduct between the low-pressure port 12 and the high-pressure port 13 to relieve pressure when the differential pressure is too large. Therefore, the piston assembly 2 needs a large movement stroke to allow the low-pressure port 12 and the high-pressure port 13 to conduct to the maximum opening. Thus, the movement strokes of the signal cap assembly 3 and the piston assembly 2 are mismatched. In this embodiment, a structure in which the second magnetic element is elastically connected to the piston body is adopted. Specifically, the piston assembly 2 includes a piston body 21 and a movable part 22. The piston body 21 is slidably disposed in the chamber 11. The piston body 21 is in contact with the side wall of the chamber 11 to keep the two sides of the chamber 11 separated by the piston body 21 relatively isolated. The second magnetic element 52 is connected to the movable part 22, which is slidably connected to the piston body 21. The sliding direction of the movable part 22 is along the sliding direction of the piston assembly 2 in the chamber 11. A second elastic element 23 is provided between the movable part 22 and the piston body 21 to drive the movable part 22 to extend towards the side where the signal cap assembly 3 is located. The second elastic element 23 is specifically a spring. Thus, when the pressure difference is abnormal, the piston assembly 2 and the second magnetic element 52 first move to the left as a whole, such as... Figure 3 As shown, when the pressure difference reaches a preset value, the second magnetic element 52 will first contact the right side wall of the second housing 15 (or, as described, the movable part 22 will first contact the right side wall of the second housing 15), thereby generating a sufficiently large magnetic force on the third magnetic element 53 to drive the signal cap assembly 3 to slide to the left and pop out to the indicator position. At this time, there is no relative displacement between the movable part 22 and the piston body 21, and the high-pressure port 13 and the low-pressure port 12 are in a partially conductive state. Figure 4As shown, when the pressure difference continues to increase beyond the preset value one, the movable part 22 no longer moves to the left, and relative displacement begins between the movable part 22 and the piston body 21. The second elastic element 23 is further compressed, and the piston body 21 continues to move to the left relative to the movable part 22. When the pressure difference increases to the preset value two, the piston body 21 reaches its maximum stroke relative to the movable part 22. At this time, the piston body 21 directly or indirectly abuts against the housing part two 15, and the high-pressure port 13 and the low-pressure port 12 reach the maximum opening state of complete conduction. The high-pressure chamber can fully release pressure to the low-pressure chamber, effectively protecting the equipment in the high-pressure chamber. This structural method solves the matching problem of different strokes between the signal cap assembly 3 and the piston assembly 2, enabling the signal cap assembly 3 and the piston assembly 2 to reliably perform their respective functions.

[0035] Specifically, when the movable part 22 does not touch the inner wall of the housing 15, the second elastic member 23 exerts a pre-force on the movable part 22. This pre-force is greater than the magnetic force exerted by the first magnetic member 51 on the third magnetic member 53 when the signal cap assembly 3 is in its normal position. This ensures that when the piston assembly 2 moves towards the signal cap assembly 3, the second magnetic member 52 can effectively push the signal cap assembly 3 towards the indicator position. This prevents the second elastic member 23 from exerting too little force on the movable part 22, causing the second magnetic member 52 to move closer to the third magnetic member 53, thus preventing the magnetic force between the second magnetic member 52 and the third magnetic member 53 from being insufficient. The second elastic element 23 is compressed and deformed, making it impossible for the second magnetic element 52 to effectively approach the third magnetic element 53. As a result, the magnetic force between the second magnetic element 52 and the third magnetic element 53 is difficult to increase to a level greater than the magnetic force generated by the first magnetic element 51 on the third magnetic element 53. Consequently, it is difficult to effectively trigger the signal cap assembly 3 to move to the indicator position. Therefore, the pre-action force generated by the second elastic element 23 on the movable part 22 must be greater than the magnetic force generated by the first magnetic element 51 on the third magnetic element 53 when the signal cap assembly 3 is in the normal position in order to accurately and reliably trigger the signal cap assembly 3 to perform mechanical warning.

[0036] Furthermore, the movable part 22 is slidably sleeved on the screw 24 screwed to the piston body 21. The axial direction of the screw 24 is along the sliding direction of the piston assembly 2. Under normal pressure differential conditions, the movable part 22 is pressed against the head of the screw 24 by the pre-action force generated by the second elastic element 23. The screw 24 extends to the right through the piston body 21 for adjustment by turning the screw 24. By turning the screw 24, the length of the head of the screw 24 extending to the left can be adjusted, which is to adjust the deformation of the second elastic element 23. In other words, adjusting the second elastic element 23 affects the... The pre-action force of the movable part 22 is also the distance between the second magnetic element 52 on the movable part 22 and the wall of the second shell 15 under the normal condition of adjusting the differential pressure, so as to realize the adjustment of the trigger stroke and flexibly meet the application requirements. When the differential pressure increases to the preset value 2, the piston body 21 reaches the maximum active stroke relative to the movable part 22. At this time, the head of the screw 24 abuts against the guide post 17 so that the piston body 21 indirectly abuts against the second shell 15, so that the piston body 21 no longer continues to move towards the second shell 15. At this time, the high pressure port 13 and the low pressure port 12 reach the maximum opening state of complete conduction.

[0037] In this embodiment, the piston body 21 is provided with a hollow hole 211. When the pressure difference between the low-pressure port 12 and the high-pressure port 13 is less than a preset value of two, the low-pressure port 12 is connected to the area space in the chamber 11 near the signal cap assembly 3 through the hollow hole 211. The fuel in the area space in the chamber 11 near the signal cap assembly 3 can be discharged into the low-pressure chamber along the path from the hollow hole 211 to the low-pressure port 12, ensuring that the piston body 21 can be stably driven to move to trigger the signal cap assembly 3 to perform a mechanical warning when the pressure difference between the low-pressure port and the high-pressure port is abnormal.

[0038] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A differential pressure annunciator, characterized by, The application relates to a signal cap assembly for a pressure gauge, which comprises a shell (1), a piston assembly (2) and a signal cap assembly (3), wherein the shell (1) is provided with a first magnetic element (51), the piston assembly (2) is provided with a second magnetic element (52), the signal cap assembly (3) is provided with a third magnetic element (53), the piston assembly (2) is slidably arranged in a cavity (11) of the shell (1), the shell (1) is provided with a low-pressure cavity port (12) and a high-pressure cavity port (13) which are communicated with the cavity (11), the signal cap assembly (3) is slidably arranged on the shell (1) and located outside the cavity (11), a first elastic element (4) is arranged between the shell (1) and the piston assembly (2) and used for driving the piston assembly (2) to a position where the low-pressure cavity port (12) is separated from the high-pressure cavity port (13) and away from the signal cap assembly (3). When the pressure difference between the low-pressure cavity port (12) and the high-pressure cavity port (13) is less than a preset value, the signal cap assembly (3) is kept in a normal position under the magnetic action force generated by the first magnetic element (51) on the third magnetic element (53); when the pressure difference between the low-pressure cavity port (12) and the high-pressure cavity port (13) reaches the preset value, the piston assembly (2) moves towards the signal cap assembly (3) against the action force of the first elastic element (4), and the signal cap assembly (3) is driven to an indicating position by the magnetic action force generated by the second magnetic element (52) on the third magnetic element (53).

2. The differential pressure alarm of claim 1, wherein, One of the first magnetic element (51) and the third magnetic element (53) is a ring-shaped magnet, and the other is a columnar magnet; the ring-shaped magnet is sleeved on the circumferential periphery of the columnar magnet; the magnetic pole directions of the first magnetic element (51) and the third magnetic element (53) are the same and along the sliding direction of the signal cap assembly (3); and the magnetic pole direction of the second magnetic element (52) is opposite to that of the first magnetic element (51).

3. The differential pressure alarm of claim 1, wherein, The second magnetic element (52) is a ring-shaped magnetic element which is sleeved on a guide column (17) arranged on the inner wall of the cavity (11) and along the sliding direction of the piston assembly (2).

4. The differential pressure alarm of claim 1, wherein, The piston assembly (2) comprises a piston main body (21) and a movable part (22), the second magnetic element (52) is connected to the movable part (22), the movable part (22) is slidably connected to the piston main body (21), the sliding direction of the movable part (22) is along the sliding direction of the piston assembly (2) in the cavity (11), and a second elastic element (23) is arranged between the movable part (22) and the piston main body (21) and used for driving the movable part (22) to extend to the side where the signal cap assembly (3) is located.

5. The differential pressure alarm of claim 4, wherein, When the movable part (22) does not touch the inner wall of the cavity (11), the second elastic element (23) has a preset action force on the movable part (22), and the preset action force is greater than the magnetic action force generated by the first magnetic element (51) on the third magnetic element (53) when the signal cap assembly (3) is in the normal position.

6. The differential pressure alarm of claim 4, wherein, The movable part (22) is sleeved on a screw rod (24) screwed with the piston body (21), the screw rod (24) penetrates through the piston body (21) to adjust the screw rod (24) by screwing, thereby adjusting the pre-action force of the second elastic member (23) on the movable part (22).

7. The differential pressure alarm of claim 4, wherein, When the pressure difference reaches the preset value one, the movable part (22) touches the inner wall of the chamber (11), and there is no relative displacement between the movable part (22) and the piston body (21), and the high-pressure cavity port (13) and the low-pressure cavity port (12) are partially communicated; When the pressure difference continues to increase to the preset value two, the relative displacement between the movable part (22) and the piston body (21) reaches the maximum, and the high-pressure cavity port (13) and the low-pressure cavity port (12) are completely communicated.

8. The differential pressure alarm of claim 7, wherein, The piston body (21) is provided with a hollow hole (211), and when the pressure difference between the low-pressure cavity port (12) and the high-pressure cavity port (13) is less than the preset value two, the low-pressure cavity port (12) is in space communication with the area on the side of the signal cap assembly (3) in the chamber (11) through the hollow hole (211).

9. The differential pressure alarm of claim 1 wherein, The shell (1) comprises a shell piece one (14) and a shell piece two (15), the shell piece one (14) is in a cylindrical shape, the inside of the shell piece one (14) constitutes the chamber (11), the shell piece two (15) is sealingly connected to one end of the shell piece one (14), the first magnetic member (51) is arranged on the shell piece two (15), and the signal cap assembly (3) is slidingly connected to the shell piece two (15).

10. The differential pressure alarm of claim 9, wherein, The signal cap assembly (3) is sleeved on the column arranged on the shell piece two (15), the shell piece two (15) is fixed with an end cover (16) through a clamping ring, and the end cover (16) limits the signal cap assembly (3).

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