CN209818839U - Emergency breaking device for fluid arm of loading and unloading tank car - Google Patents

Abstract

The utility model discloses a loading and unloading tank wagon fluid arm promptly breaks device, including the coupling assembling of connecting loading and unloading tank wagon and oil depot, the coupling assembling include the upper tube body of connecting the loading and unloading tank wagon and the lower tube body of connecting the oil depot, be equipped with the upper broken pipe, break valve, lower broken pipe that connect gradually between upper tube body and the lower tube body; an upper snap ring connected with a loading and unloading tank car is arranged between the upper breaking pipe and the upper pipe body, and a lower snap ring connected with an oil depot is arranged between the lower breaking pipe and the lower pipe body; the breaking valve is vertically arranged, and the upper pipe body and the lower pipe body are horizontally arranged. The utility model discloses make full use of breaks the characteristics that the radial atress critical value of valve is less than the axial atress critical value, just can break off at the radial atress in-process of breaking the valve to realize the quick disconnection of pipeline, go up the pipeline that snap ring, lower snap ring will have broken behind the pipeline disconnection and fix the emergence that prevents the secondary accident.

Description

Emergency breaking device for fluid arm of loading and unloading tank car

Technical Field

The utility model relates to an promptly break device, specifically indicate a loading and unloading tank wagon fluid arm promptly breaks device.

Background

Various potential safety hazards of the cryogenic fluid in the process of loading and unloading the tanker, for example, due to misoperation or slipping reasons, the loading and unloading tanker drives away from a working area under the condition that the loading and unloading tanker is not separated from a hose (or equipment), and a connecting pipe is broken to cause a large amount of raw materials to leak, so that a great safety accident is caused; or the tank car is being loaded and unloaded, and the tank car needs to be rapidly driven away from the site due to sudden fire on the site and the like, the tank car and the loading and unloading arm cannot be separated by a normal method, and serious personal and property safety accidents can be caused, thereby causing economic loss and environmental pollution. The existing cryogenic fluid arm is equipped with an emergency break-off valve in the transverse direction. The device can produce axial tension to the fluid arm when the tank wagon drives away from the operation place to let the abruption valve atress, after reaching the critical value, abruption valve disconnection, the fluid arm divides into sealed left and right sides two parts. Although the existing scheme can effectively disconnect the breaking valve, the breaking valve can be disconnected only after the axial tension exceeds a critical value after the fluid arm is completely pulled. In summary, how to reduce the situation of a large amount of fluid leaking due to sudden sliding or starting of the loading and unloading tanker in the process of adding fluid, so as to reduce the pollution of the fluid to the environment and reduce the potential safety hazard, is a technical problem to be solved by those skilled in the art.

Disclosure of Invention

The utility model provides a simple structure, safe in utilization, leak less loading and unloading tank wagon fluid arm promptly snap-off device.

A loading and unloading tank wagon fluid arm promptly breaks the apparatus, including connecting assembly to connect loading and unloading tank wagon and oil depot, the said connecting assembly includes connecting the upper tube body of the loading and unloading tank wagon and connecting the lower tube body of the oil depot, there are upper that connects sequentially that breaks the pipe, breaks the valve, pulls down and breaks the pipe between said upper tube body and lower tube body; an upper snap ring connected with a loading and unloading tank car is arranged between the upper breaking pipe and the upper pipe body, and a lower snap ring connected with an oil depot is arranged between the lower breaking pipe and the lower pipe body; the upper pipe body and the lower pipe body are horizontally arranged, a snapping ring groove is formed in the outer wall of the middle of the snapping valve, and an inner cavity of the snapping valve comprises an upper cavity and a lower cavity which are symmetrically arranged on two sides of the snapping ring groove; the first valve core is arranged in the upper cavity and provided with a first mandrel and a first cut-off part which can be in sealing contact with the inner wall of the bottom of the upper cavity; the first valve core supporting seat is sleeved on the first mandrel and is provided with a first through hole communicated with the upper cavity for fluid to pass through; the first compression spring can drive the first valve core to move together with the thrust of the fluid at the top so as to enable the first cut-off part to be in sealing contact with the inner wall at the bottom of the upper cavity, and the first compression spring is sleeved on the first mandrel and is positioned between the first valve core supporting seat and the first cut-off part; the inlet joint is connected with the upper end of the breaking valve, and a first limiting bulge for limiting the first valve core supporting seat to move upwards is arranged on the inner wall of the inlet joint; the second valve core is arranged in the lower cavity and provided with a second mandrel and a second cut-off part which can be in sealing contact with the inner wall of the top of the lower cavity, and the second cut-off part is abutted against the first cut-off part; the second valve core supporting seat is sleeved on the second core shaft and is provided with a second through hole communicated with the lower cavity for fluid to pass through; the second compression spring can drive the second valve core to move together with the thrust of bottom fluid so as to enable the second cut-off part to be in sealing contact with the inner wall of the top of the lower cavity, and the second compression spring is sleeved on the second core shaft and is positioned between the second valve core supporting seat and the second cut-off part; and the outlet joint is connected with the lower end of the breaking valve, and a second limiting bulge for limiting the second valve core supporting seat to move downwards is arranged on the inner wall of the outlet joint. The existing emergency snapping device is broken by a large force after being unfolded completely, and the unfolding process needs a certain time, so that the device is not quick enough in response. After the abruption valve is vertically arranged and installed, the abruption valve mainly bears radial force, the characteristics that the radial stress critical value of the abruption valve is lower than the axial stress critical value are fully utilized, and the abruption valve can be disconnected in the process of unfolding the fluid arm, so that the pipeline can be quickly disconnected, and the disconnected pipeline is fixed by the upper clamping ring and the lower clamping ring after the pipeline is disconnected, and secondary accidents are prevented.

The second valve core and the first valve core are coaxial and symmetrically arranged at two sides of the snapping ring groove; a first sealing ring is further arranged between the inlet joint and the upper end of the loading and unloading tank car fluid arm emergency snapping device body, and a second sealing ring is further arranged between the outlet joint and the lower end of the loading and unloading tank car fluid arm emergency snapping device body.

The inlet joint is sleeved at the upper end of the breaking valve, and the outlet joint is sleeved at the lower end of the breaking valve.

A first mounting ring groove is formed in the inner wall of the inlet joint, and the first sealing ring is arranged in the first mounting ring groove; and a second mounting ring groove is formed in the inner wall of the outlet connector, and the second sealing ring is arranged in the second mounting ring groove.

The first mounting ring groove is formed in the bottom end of the inlet connector, and the second mounting ring groove is formed in the top end of the outlet connector.

The first sealing ring and the second sealing ring are both spring actuating sealing rings, and each spring actuating sealing ring comprises a sealing ring body with an inner lip and a spring arranged in the inner lip.

The inlet joint is in threaded connection with the upper end of the breaking valve, and the outlet joint is in threaded connection with the lower end of the loading and unloading tank car fluid arm emergency breaking device body. Preferably, in the above-described snap valve, the first cut portion is tapered from the middle to both ends, and the second cut portion is tapered from the middle to both ends; the cross section shapes of the first cut-off part and the second cut-off part are both circular, the cross section shapes of the inner walls of the upper cavity and the lower cavity are both circular, the maximum cross section area of the first cut-off part is larger than the inner diameter of the bottom of the upper cavity, and the maximum cross section diameter of the second cut-off part is larger than the diameter of the bottom of the lower cavity.

According to the technical scheme, the utility model provides an it includes that break valve, first case bearing seat, first compression spring, import connect, second case bearing seat, second compression spring and outlet joint to break valve that the utility model provides; the outer wall of the middle part of the snapping valve is provided with a snapping ring groove, and the inner cavity of the snapping valve comprises an upper cavity and a lower cavity which are symmetrically arranged at two sides of the snapping ring groove; the first valve core is arranged in the upper cavity and is provided with a first mandrel and a first cut-off part which can be in sealing contact with the inner wall of the bottom of the upper cavity; the first valve core supporting seat is sleeved on the first mandrel and is provided with a first through hole communicated with the upper cavity for fluid to pass through; the first compression spring and the thrust of the fluid at the top can drive the first valve core to move together so as to enable the first cut-off part to be in sealing contact with the inner wall at the bottom of the upper cavity, and the first compression spring is sleeved on the first mandrel and positioned between the first valve core supporting seat and the first cut-off part; the inlet joint is connected with the upper end of the snapping valve body, and the inner wall of the inlet joint is provided with a first limiting bulge for limiting the upward movement of the first valve core supporting seat; the second valve core is arranged in the lower cavity and is provided with a second core shaft and a second cut-off part which can be in sealing contact with the inner wall of the top of the lower cavity, and the second cut-off part is abutted against the first cut-off part; the second valve core supporting seat is sleeved on the second core shaft and is provided with a second through hole communicated with the lower cavity for fluid to pass through; the second compression spring and the thrust of the fluid at the bottom can drive the second valve core to move together so that the second cut-off part is in sealing contact with the inner wall at the top of the lower cavity and is sleeved on the second mandrel and positioned between the second valve core supporting seat and the second cut-off part; the outlet joint is connected with the lower end of the breaking valve, and the inner wall of the outlet joint is provided with a second limiting bulge for limiting the second valve core supporting seat to move downwards.

The utility model takes the snapping ring groove as the snapping area of the snapping valve, when in use, the inlet joint is fixedly connected with the liquid adding pipe seat on the gas dispenser, and the outlet joint is connected with the liquid adding hose; at the moment, fluid in the gas filling machine enters the upper cavity of the breaking valve from the inlet joint through the first through hole of the first valve core supporting seat, then flows through the lower cavity and flows out of the second through hole of the second valve core supporting seat into the liquid filling hose.

In the process of adding fluid, if the loading and unloading tank wagon slides suddenly or starts, the utility model discloses a stretch-break valve can be separated into upper and lower two parts along the stretch-break annular under the exogenic action, and the second part of cuting separates with first part of cuting this moment, and the dual function of the restoring force of first compression spring and the thrust of top fluid can drive first case and move down so that first part of cuting makes the inner wall sealing contact of upper cavity bottom, and the dual function of the restoring force of second compression spring and the thrust of bottom fluid can drive second valve core to move up simultaneously so that the second part of cuting makes the inner wall sealing contact at lower cavity top, and then cuts upper chamber and lower chamber simultaneously, forms two check valves from top to bottom, can prevent the fluid leakage; therefore the utility model discloses having reduced because of the car slides suddenly or start the condition that causes a large amount of leakages of fluid at the in-process of joining the fluid, and then having reduced the pollution that the fluid caused to the environment, reduced the potential safety hazard simultaneously, reduced the probability of occurence of failure. And simultaneously, the utility model provides a snapping valve structure is fairly simple, and the volume is less, the installation of being convenient for, and the seal performance is better, is applicable to the low temperature medium, has improved the commonality.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural view of an emergency snapping device for a fluid arm of a loading and unloading tank car according to an embodiment of the present invention;

fig. 2 is a schematic structural view of the snap-off valve of the present invention.

Detailed Description

The embodiment of the utility model provides a snapping valve can reduce because of the car slides suddenly or starts the condition that causes a large amount of leakages of fluid at the in-process of joining the fluid, and then has reduced the pollution that the fluid caused to the environment, has reduced the potential safety hazard simultaneously.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Referring to fig. 1, an embodiment of the present invention provides a loading and unloading tank wagon fluid arm emergency snapping device, including a connecting assembly connecting the loading and unloading tank wagon and an oil depot, where the connecting assembly includes an upper tube 12 connecting the loading and unloading tank wagon and a lower tube 16 connecting the oil depot, an upper snapping pipe 13, a snapping valve 6, and a lower snapping pipe 15 are disposed between the upper tube 12 and the lower tube 16, the upper snapping pipe 17 is disposed between the upper snapping pipe 13 and the upper tube 12, and a lower snapping ring 18 is disposed between the lower snapping pipe 13 and the lower tube 16.

The structure is preferably that the snapping valve 6 is vertically arranged, the upper pipe body and the lower pipe body are horizontally arranged, the outer wall of the middle part of the snapping valve is provided with a snapping ring groove, and the inner cavity of the snapping valve comprises an upper cavity and a lower cavity which are symmetrically arranged at two sides of the snapping ring groove; the breaking valve comprises a breaking valve 6, a first valve core 5, a first valve core supporting seat 1, a first compression spring 3, an inlet connector 2, a second valve core 7, a second valve core supporting seat 10, a second compression spring 11 and an outlet connector 9; the outer wall of the middle part of the snapping valve 6 is provided with a snapping ring groove 61, and the inner cavity of the snapping valve 6 comprises an upper cavity and a lower cavity which are symmetrically arranged at two sides of the snapping ring groove 61; the first valve core 5 is arranged in the upper cavity and is provided with a first mandrel and a first cut-off part which can be in sealing contact with the inner wall of the bottom of the upper cavity; the first valve core supporting seat 1 is sleeved on the first mandrel and is provided with a first through hole communicated with the upper cavity for fluid to pass through; the first compression spring 3 and the thrust of the fluid at the top can drive the first valve core 5 to move together so as to enable the first cut-off part to be in sealing contact with the inner wall of the bottom of the upper cavity, and the first compression spring 3 is sleeved on the first mandrel and is positioned between the first valve core supporting seat 1 and the first cut-off part; the inlet joint 2 is connected with the upper end of the snapping valve 6, and the inner wall of the inlet joint is provided with a first limiting bulge 21 for limiting the upward movement of the first valve core supporting seat 1; the second valve core 7 is arranged in the lower cavity and is provided with a second core shaft and a second cut-off part which can be in sealing contact with the inner wall of the top of the lower cavity, and the second cut-off part is abutted against the first cut-off part; the second valve core supporting seat 10 is sleeved on the second core shaft and is provided with a second through hole communicated with the lower cavity for fluid to pass through; the second compression spring 11 and the thrust of the fluid at the bottom can drive the second valve core 7 to move together so that the second cut-off part is in sealing contact with the inner wall at the top of the lower cavity, is sleeved on the second core shaft and is positioned between the second valve core supporting seat 10 and the second cut-off part; the outlet joint 9 is connected with the lower end of the breaking valve 6, and the inner wall of the outlet joint is provided with a second limiting bulge 91 for limiting the downward movement of the second valve core supporting seat 10.

The utility model takes the snap ring groove 61 as the snap zone of the snap valve, when in use, the inlet joint 2 is fixedly connected with the liquid adding pipe seat on the gas dispenser, and the outlet joint 9 is connected with the liquid adding hose; at the moment, fluid in the gas filling machine enters the upper cavity of the breaking valve 6 from the inlet joint 2 through the first through hole of the first valve core supporting seat 1, then flows through the lower cavity, and flows out of the second through hole of the second valve core supporting seat 10 into the liquid filling hose.

In the process of adding fluid, if the automobile slides or starts suddenly, the utility model discloses a snap-off valve body 6 can separate into upper and lower two parts along snap-off annular groove 61 under the exogenic action, the second part of cuting separates with first part of cuting this moment, the dual function of the restoring force of first compression spring 3 and the thrust of top fluid can drive first case 5 to move down so that first part of cuting makes the inner wall sealing contact of upper cavity bottom form hard seal promptly, the dual function of the restoring force of second compression spring 11 and the thrust of bottom fluid can drive second valve core 7 to move up simultaneously so that the second part of cuting makes the inner wall sealing contact at lower cavity top form hard seal promptly, and then cut off upper cavity and lower cavity simultaneously, form upper and lower two check valves, can prevent the fluid from leaking outward; therefore the utility model discloses having reduced because of the car slides suddenly or start the condition that causes a large amount of leakages of fluid at the in-process of joining the fluid, and then having reduced the pollution that the fluid caused to the environment, reduced the potential safety hazard simultaneously, reduced the probability of occurence of failure.

And simultaneously, the utility model provides a snapping valve structure is fairly simple, and the volume is less, the installation of being convenient for, and the seal performance is better, is applicable to the low temperature medium, has improved the commonality.

In an embodiment of the present invention, the second valve element 7 and the first valve element 5 are coaxial and symmetrically disposed on both sides of the snap ring groove 61; as shown in fig. 1, the second valve core 7 and the first valve core 5 have the same shape, so that the valve core is convenient to process and manufacture and is convenient to assemble; meanwhile, the second valve core 7 and the first valve core 5 which are mutually abutted can effectively prevent the impact of the fluid, so that the fluid flows more stably.

Preferably, a first sealing ring 4 is further disposed between the inlet joint 2 and the upper end of the breaking valve 6, and a second sealing ring 8 is further disposed between the outlet joint 9 and the lower end of the breaking valve 6. The utility model discloses a first sealing washer 4 has improved the radial seal nature between imported joint 2 and the breaking valve 6, has improved the radial seal nature between outlet connection 9 and the breaking valve 6 through second sealing washer 8, can reduce from imported joint 2 and break between the valve 6 or from the fluid of leaking between outlet connection 9 and the breaking valve 6, has improved fail safe nature.

Specifically, the inlet joint 2 is sleeved on the upper end of the snapping valve 6, and the outlet joint 9 is sleeved on the lower end of the snapping valve body 6. Therefore, the inlet connector 2 and the outlet connector 9 are wrapped outside the snapping valve 6, and the two connectors are large in size and convenient to install on a liquid feeding pipe seat and a liquid feeding hose. The inlet connector 2 may be fitted to the upper end of the breaking valve 6, and the outlet connector 9 may be fitted to the lower end of the breaking valve 6.

Further, a first mounting ring groove is formed in the inner wall of the inlet joint 2, and a first sealing ring 4 is arranged in the first mounting ring groove; a second mounting ring groove is formed in the inner wall of the outlet joint 9, and the second sealing ring 8 is arranged in the second mounting ring groove. The utility model discloses a first mounting ring groove carries on spacingly to first sealing washer 4, carries on spacingly to second sealing washer 8 through the second mounting ring groove, can reduce the axial float that the sealing washer takes place, has guaranteed sealed effect.

In order to further optimize the above technical solution, the first mounting ring groove is provided at the bottom end of the inlet joint 2, and the second mounting ring groove is provided at the top end of the outlet joint 9. At this time, the first sealing ring 4 in the first mounting ring groove also enables the upper end of the breaking valve 6 and the bottom end face of the inlet joint 2 to form end face seal, and the second sealing ring 8 in the second mounting ring groove also enables the lower end of the breaking valve 6 and the top end face of the outlet joint 9 to form end face seal, so that the sealing performance of the joint and the breaking valve 6 is further improved.

The first seal ring 4 and the second seal ring 8 are both spring actuated seal rings, and each spring actuated seal ring comprises a seal ring body with an inner lip and a spring arranged in the inner lip. The spring actuated sealing ring has good sealing effect and long sealing time, and the service life of the breaking valve is prolonged. Of course, the first seal ring 4 and the second seal ring 8 may be O-rings, gaskets, or the like.

For the convenience of assembly, the inlet connector 2 is in threaded connection with the upper end of the breaking valve 6, and the outlet connector 9 is in threaded connection with the lower end of the breaking valve 6. Specifically, a first internal thread is arranged on the inner wall of the inlet joint 2, and a first external thread matched with the first internal thread is arranged on the outer wall of the upper end of the snapping valve 6; a second internal thread is arranged on the inner wall of the outlet joint 9, and a second external thread matched with the second internal thread is arranged on the outer wall of the lower end of the snapping valve 6. At this moment, the inlet connector 2 and the outlet connector 9 are detachably connected with the breaking valve 6, so that the sealing ring is convenient to install and replace, and meanwhile, the breaking valve is convenient to maintain.

In order to achieve a good snap-off effect, the snap-off ring groove 61 has a V-shaped groove bottom, and the minimum wall thickness of the snap-off valve 6 at the V-shaped groove bottom is 1mm to 1.5 mm. The wall thickness of the breaking valve 6 at the bottom of the V-shaped groove is gradually reduced, so that the breaking is facilitated; specifically, the minimum wall thickness of the snapping valve 6 at the bottom of the V-shaped groove is 1mm, the wall thickness is thin, the snapping valve can be snapped in a snapping area rapidly when external force is applied, and safety and reliability are improved.

In a specific embodiment of the present invention, the snapping valve 6 is a copper alloy valve body, which has good snapping performance, is not easy to generate sparks, and has high safety and reliability; of course, the snap valve body 6 may be a stainless steel valve body.

Further, the inlet joint 2 and the outlet joint 9 are both stainless steel joints. The stainless steel joint has high strength and can better limit the valve core supporting seat.

Preferably, the first cut-off part is gradually reduced from the middle to the two ends respectively, and the second cut-off part is gradually reduced from the middle to the two ends respectively; therefore, when the breaking valve is broken, the hard seal is formed by the middle part of the cut-off part and the inner wall of the breaking valve 6, and at the moment, the contact area between the cut-off part and the breaking valve 6 is large, so that the cut-off effect is ensured, and the safety and the reliability are improved. Above-mentioned truncation portion also can be for other shapes, can also adopt other sealed modes when breaking, if set up the annular and set up the sealing washer in the annular in truncation portion, utilize the sealing washer to make truncation portion and the sealed cooperation of breaking valve when breaking to reach the same effect that prevents the outer hourglass of fluid, the utility model discloses no longer give unnecessary details one by one.

For convenience of processing, the cross section shapes of the first cut-off part and the second cut-off part are both circular, the cross section shapes of the inner walls of the upper cavity and the lower cavity are both circular, the maximum cross section diameter of the first cut-off part is larger than the inner diameter of the bottom of the upper cavity, and the maximum cross section diameter of the second cut-off part is larger than the inner diameter of the bottom of the lower cavity, so that a better cut-off effect can be guaranteed.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (7)

1. An emergency snapping device for a fluid arm of a loading and unloading tank wagon comprises a connecting assembly for connecting the loading and unloading tank wagon and an oil depot, wherein the connecting assembly comprises an upper tube body for connecting the loading and unloading tank wagon and a lower tube body for connecting the oil depot, and is characterized in that an upper snapping tube, a snapping valve and a lower snapping tube which are sequentially connected are arranged between the upper tube body and the lower tube body; an upper snap ring connected with a loading and unloading tank car is arranged between the upper breaking pipe and the upper pipe body, and a lower snap ring connected with an oil depot is arranged between the lower breaking pipe and the lower pipe body; the upper pipe body and the lower pipe body are horizontally arranged, a snapping ring groove is formed in the outer wall of the middle of the snapping valve, and an inner cavity of the snapping valve comprises an upper cavity and a lower cavity which are symmetrically arranged on two sides of the snapping ring groove; the first valve core is arranged in the upper cavity and provided with a first mandrel and a first cut-off part which can be in sealing contact with the inner wall of the bottom of the upper cavity; the first valve core supporting seat is sleeved on the first mandrel and is provided with a first through hole communicated with the upper cavity for fluid to pass through; the first compression spring can drive the first valve core to move together with the thrust of the fluid at the top so as to enable the first cut-off part to be in sealing contact with the inner wall of the bottom of the upper cavity, and the first compression spring is sleeved on the first mandrel and is positioned between the first valve core supporting seat and the first cut-off part; the inlet joint is connected with the upper end of the breaking valve, and a first limiting bulge for limiting the first valve core supporting seat to move upwards is arranged on the inner wall of the inlet joint; the second valve core is arranged in the lower cavity and provided with a second mandrel and a second cut-off part which can be in sealing contact with the inner wall of the top of the lower cavity, and the second cut-off part is abutted against the first cut-off part; the second valve core supporting seat is sleeved on the second core shaft and is provided with a second through hole communicated with the lower cavity for fluid to pass through; the second compression spring can drive the second valve core to move together with the thrust of bottom fluid so as to enable the second cut-off part to be in sealing contact with the inner wall of the top of the lower cavity, and the second compression spring is sleeved on the second core shaft and is positioned between the second valve core supporting seat and the second cut-off part; and the outlet joint is connected with the lower end of the breaking valve, and a second limiting bulge for limiting the second valve core supporting seat to move downwards is arranged on the inner wall of the outlet joint.

2. The fluid arm emergency snap-off device of claim 1, wherein said second spool and said first spool are coaxially and symmetrically disposed on opposite sides of said snap-off ring groove; a first sealing ring is further arranged between the inlet joint and the upper end of the loading and unloading tank car fluid arm emergency snapping device body, and a second sealing ring is further arranged between the outlet joint and the lower end of the loading and unloading tank car fluid arm emergency snapping device body.

3. The emergency snapping apparatus for fluid arms of a loading/unloading tanker according to claim 2, wherein said inlet fitting is externally fitted over an upper end of said snapping valve and said outlet fitting is externally fitted over a lower end of said snapping valve.

4. The emergency snapping apparatus for loading and unloading a fluid arm of a tank car according to claim 3, wherein a first mounting ring groove is formed on an inner wall of the inlet joint, and the first sealing ring is disposed in the first mounting ring groove; and a second mounting ring groove is formed in the inner wall of the outlet connector, and the second sealing ring is arranged in the second mounting ring groove.

5. The fluid arm emergency snap-off device of claim 4, wherein said first mounting ring groove is disposed at a bottom end of said inlet fitting and said second mounting ring groove is disposed at a top end of said outlet fitting.

6. The load handling tank car fluid arm emergency snap-off device of claim 5, wherein said first seal ring and said second seal ring are each spring actuated seal rings comprising a seal ring body having an inner lip and a spring disposed within said inner lip.

7. The loading and unloading tanker fluid arm emergency snap-off device of claim 3, wherein said inlet fitting is threadably connected to an upper end of said snap-off valve, and said outlet fitting is threadably connected to a lower end of said loading and unloading tanker fluid arm emergency snap-off device body.