Patent Grant
8573246
The invention generally relates to a cryogenic vessel for storing cryogenic fluid. More particularly, it relates to an automatic filling termination device for the cryogenic vessel and the cryogenic vessel with the automatic filling termination device.
Cryogenic mediums, such as liquid oxygen, liquid nitrogen, liquid argon, liquefied natural gas (LNG), etc., are materials commonly used in industry. They have lower working temperatures and are usually stored in cryogenic vessels in liquid form. For example, the working temperature of liquid nitrogen is generally around −196° C. In the course of filling a cryogenic liquid medium from a bulk supply tank into a cryogenic vessel, the medium will vaporize continuously, resulting in pressure in the vessel rising. Such pressure rising causes the pressure difference between the bulk supply tank and the inside of the vessel, decreasing or even vanishing, so that the filling process cannot continue. Moreover, the over-high pressure in the vessel will hide some safety troubles.
Hence, filling with gas-let-out is usually adopted. As shown in
In practice, the cryogenic medium stored in a cryogenic vessel is usually in a gas-liquid equilibrium state. Thus, the filling rate of liquid within the vessel needs to be controlled during the filling process. In the prior art, an overflow pipe 4 is commonly arranged on the vessel 1. The overflow pipe 4 is opened during the filling process. When liquid begins to flow out from the overflow pipe 4, it means that the vessel reaches the designed filling rate. At this time, valves for the bulk supply tank and for pipe(s) on the vessel need to be respectively and manually turned off, so as to stop filling. In this way, however, some medium will be wasted in liquid form.
The cryogenic medium is usually obtained through various complicated processes, which consume a large amount of additional energy and money. In the existing filling manner, the medium discharged from the exhaust pipe 3 and the overflow pipe 4 will be wasted inevitably. Accordingly, not only the environment will be contaminated but also the resources will be wasted. Additionally, there will be hidden safety troubles if the wasted medium is not handled properly. Therefore, how to prevent the medium from being wasted during the filling process is a problem demanding prompt solution.
Furthermore, the existing filling manner requires operators to focus their attention on opening and closing the corresponding valves of pipes and pipelines in time. If, for example, the overflow pipe 4 is forgotten to be opened during the filling process, the liquid within the vessel might exceed the safe liquid level, thereby causing hazards, such as pressure holding, or even vessel explosion, etc.
An object of the present invention is to provide an automatic filling termination device for a cryogenic vessel, which can automatically terminate the filling process when a predetermined volume of the cryogenic medium in the vessel has been reached.
Another object of the present invention is to provide a cryogenic vessel to prevent the cryogenic medium from being wasted during filling process.
In order to achieve one of the above objects of the invention, an automatic filling termination device for a cryogenic vessel with an inlet pipe is provided. Said device comprises: a body with a chamber, defined in the cryogenic vessel and provided with an inlet opening communicated with the inlet pipe for filling cryogenic medium into the chamber, and an outlet opening arranged on the top wall of the body for discharging the cryogenic medium in the chamber into the cryogenic vessel; a flow termination member for blocking the outlet opening of the body, defined in the chamber of the body and has a predetermined weight so as not to be floated in the cryogenic medium; a floater, located outside the body and being capable of moving up and down when the liquid level of the cryogenic medium as filled into the cryogenic vessel is changed; and a connection, penetrated through the outlet opening of the body to connect the flow termination member with the floater, wherein the internal diameter of the outlet opening is greater than the outer diameter of the connection by a predetermined dimension.
The automatic filling termination device can further comprise a flow disturbing plate disposed between the outlet opening of the body and the floater. The connection penetrates through the flow disturbing plate via a through hole disposed thereon, wherein the internal diameter of the through hole is approximately equal to the outer diameter of the connection.
The flow disturbing plate can be configured into a curved shape so as to increase the splashing down area of the medium impact thereon.
Preferably, the flow disturbing plate can be configured into a shape of a spherical crown.
The flow disturbing plate can be located at a constant distance from the outlet opening of the body, so as to maintain the stability of the splashing.
The flow disturbing plate can be fixed to the inlet pipe of the cryogenic vessel.
The body of the automatic filling termination device can be fixed to an inner wall of the cryogenic vessel via at least one fixing member.
The flow disturbing plate can be fixed to said at least one fixing member.
The inner surface of the top wall of the body can be configured into a concave surface for matching the flow termination member so that the flow termination member can tightly close the outlet opening when the floater goes up with the liquid level of the cryogenic medium.
The flow termination member can be configured into a spherical shape.
The inlet opening can be arranged on the side wall of the body.
In order to achieve another object of the invention, a cryogenic vessel for storing a cryogenic medium is provided. Said cryogenic vessel is equipped with an inlet duct for filling the cryogenic medium thereinto. Said cryogenic vessel is further equipped with an automatic filling termination device comprising: a body with a chamber, defined in the cryogenic vessel and provided with an inlet opening, communicated with the inlet pipe for filling cryogenic medium into the chamber, and an outlet opening, arranged on the top wall of the body for discharging the cryogenic medium in the chamber into the cryogenic vessel; a flow termination member for blocking the outlet opening of the body, defined in the chamber of the body and has a predetermined weight so as not to be floated in the cryogenic medium; a floater, located outside the body and being capable of moving up and down when the liquid level of the cryogenic medium as filled into the cryogenic vessel is changed; and a connection, penetrated through the outlet opening of the body to connect the flow termination member with the floater, wherein the internal diameter of the outlet opening is greater than the outer diameter of the connection by a predetermined dimension. When the liquid or liquefied cryogenic medium within the cryogenic vessel reaches a predetermined liquid level, the floater floats upwardly and makes the flow termination member reach the top wall of the body and block the outlet opening.
The automatic filling termination device can be located at a position close to the top portion of the cryogenic vessel.
According to the present invention, the vessel can be filled without any medium discharging therefrom, i.e. realizing a non-loss filling, which can avoid the waste of the cryogenic medium and reduce the cost, and is of great advantage to the environment. By determining the mounting position of the automatic filling termination device through calculation, the volume of liquid filled into the vessel can be accurately controlled, so that the overfilling phenomenon and overpressure hazards (e.g. vessel explosion), which potentially exist in the prior art, can be completely avoided. When filling the medium into the cryogenic vessel of the present invention, there is no need to open the valves of the exhaust and overflow pipes, if such pipes are arranged. There is even no need to equip the exhaust pipe and/or the overflow pipe on the vessel. The automatic filling termination device according to the present invention can be particularly designed depending on actual demands, so as to meet the clients' requirements for different filling rates. In addition, the automatic filling termination device of the present invention has a very small size as comparing with the size of the vessel, so that it almost doesn't impact the loading volume of the vessel where it is arranged thereon.
In the following, the invention will be described in greater detail by way of exemplary embodiments in conjunction with the accompanying drawings.
As shown in
As shown in
The flow termination member 22 is designed and configured to have sufficient weight so that it cannot be floated in the cryogenic medium by itself. Thus, without other external force, the flow termination member 22 will stay at the bottom of the chamber 214, as shown in
According to one embodiment of the invention, the inner surface of the top wall 212 of the body 21 can be shaped and configured to match the outer profile of the flow termination member 22, enabling the outlet opening 216 to be blocked and sealed by the flow termination member 22 more tightly. For example, the flow termination member 22 may have a spherical overall shape, and the inner surface of the top wall 212 may have a tapered concave surface 217 (see
Because the floater 23 is located right above the outlet opening 216, the cryogenic medium spurting out from the outlet opening 216, may impact the floater 23. Such impact may cause a false action of the flow termination member 22. In particular, due to such impact, the floater 23 may move upwardly before the predetermined level in the vessel 10 has been reached, pulling the flow termination member 22 to move upwardly with it and even block the opening 216. In order to solve this problem, a flow disturbing plate 25 is preferably disposed between the outlet opening 216 and the floater 23. The flow disturbing plate 25 is provided with a through hole, through which the connection 24 can pass. The internal diameter of the through hole is designed to be slightly greater than but approximately equal to the outer diameter of the connection 24, so as to reduce as much as possible the impacts of the cryogenic medium flow spurting out from the outlet opening 216 to the floater 23. In this way, the greater most of the cryogenic fluid spurting out from the outlet opening 216 will spurt onto the lower surface of the flow disturbing plate 25 and then splash down into the vessel inside, so that the positional stability of the floater 23 will not be affected. Preferably, the flow disturbing plate 25 is shaped to have a curved lower surface, such as a spherical-crowned or a paraboloidal surface, which is convex or concave towards the floater 23, so that the splashing down area of the medium into the vessel can be also increased. Preferably, the flow disturbing plate 25 can be located at a constant distance from the outlet opening 216, for example by fixing it to the inlet pipe 12 (see
Preferably, the automatic filling termination device 20 of the present invention further comprises one or more fixing members 27, each of which is fixed to the body 21 at its one end and to the inner wall of the vessel 10 at its other end, so as to improve the stress condition between the liquid inlet pipe 12 and the body 21 of the automatic filling termination device 20. For example, the fixing members 27 can be fixed, preferably welded, to the head portion and/or cylinder portion of the inner wall of the vessel. According to practical requirement, the fixing members 27 can be configured into any suitable structure and shape. Preferably, all the fixing members 27 together with the liquid inlet pipe 12 can be arranged uniformly or symmetrically around the body 21. The flow disturbing plate 25 can be further fixed to the at least one fixing member 27. Alternatively, said plate 25 can be only fixed to one or more fixing members 27.
Preferably, all components and parts of the automatic filling termination device 20 according to the invention, such as the body 21, the flow termination member 22, the floater 23, the connection 24, the flow disturbing plate 25 and/or the fixing members 27, are made of cryogenic material, such as stainless steel.
The process of filling the cryogenic vessel 10 with cryogenic medium by using the automatic filling termination device 20 according to the present invention will now be described in detail.
In the beginning of the filling process, the flow termination member 22 is located at the bottom of the inner chamber 214 of the body 21 due to the action of gravity. During the filling, the liquid or liquefied cryogenic medium in the bulk supply tank (not shown) first flows into the inner chamber 214 of the body via the liquid inlet pipe 12 and the inlet opening 215, and then into the inside 11 of the vessel 10 via the outlet opening 216. Commonly, the cryogenic medium in the bulk supply tank has a greater pressure and a lower temperature than the pressure and the temperature within the vessel to be filled. Thus, the medium just spurting out from the outlet opening 216 has a lower temperature, too. The automatic filling termination device 20 is arranged preferably at a position close to the top of the vessel, so that the medium vapor gathering in the upper portion of the vessel inside 11 can be cooled or even re-liquefied through said medium just spurting out. In this way, the pressure in the vessel 10 is reduced effectively without exhausting any vapor through the exhaust pipe, so that the waste of the medium vapor is avoided. The splashing range of the medium spurting into the vessel inside can be optimized by properly sizing and configuring the flow disturbing plate 25, so as to better cool the medium vapor.
As the liquid level within the vessel 10 rises, the buoyancy force to the floater 23 by the liquid or liquefied medium is generated and gradually increased, so as to allowing the flow termination member 22 float upwardly in company with the floater 23 connected to the flow termination member 22 by the connector 24. When the liquid or liquefied medium inside the vessel arrives at the predetermined liquid level, the floater 23 floats upwardly to the very height that makes the flow termination member 22 reach the top of the inner chamber 214 of the body and block the outlet opening 216, as shown in
Generally, the vaporing speed of the cryogenic medium is very fast. After the outlet opening 216 of the body 21 is blocked, the pressure within the liquid inlet pipe 12 and the inner chamber 214 rises rapidly, e.g. increasing about 2-5 bar per second. At the same time, the flow speed of the medium drops rapidly and even drops to zero. If detecting such sudden change in pressure and/or flow speed, a pressure gauge and/or a flow meter mounted in the filling pipelines connecting the bulk supply tank with the vessel will send a “cut-off” signal to a filling pump (not shown) supplying power to the bulk supply tank. Once the filling pump receives said “cut-off” signal, it stops. Thus, the entire filling process is automatically terminated. Of course, the automatic termination of the filling possess can also be realized by using other signals. It should be noted that, because the filling possess can be automatically terminated according to the present invention, there is no need to manually close the bulk supply tank. Therefore, the bulk supply tank can be placed far away from the vessel to be filled. Thus, the safety of the filling process is enhanced.
Filling a vessel of the prior art, which has no overfilling protective device, at a high pressure tends to bring on a hazard of overfilling. Moreover, because the filling process in the prior art is accompanied with the discharge of the cryogenic medium vapor, and there is a time interval between the observation of liquid flowing out from the overflow pipe and the manual operation of closing the related valves, it is not uneconomical in the prior art to fill at a high pressure. Therefore, the vessel in the prior art can be filled only by a lower filling speed, thus more filling time is needed. The cryogenic vessel equipped with the automatic filling termination device according to the invention can automatically and immediately terminate the filling operation when the predetermined liquid level is reached, thereby avoiding an overfilling phenomenon. Therefore, the vessel according to the present invention can be filled at a high pressure, so that rapid filling can be realized. For instance, the cryogenic vessel with a capacity less than about 2000 L can be filled within about 3 to about 20 minutes.
According to the invention, the filling can be performed without discharging any medium from the vessel, that is, a non-loss filling can be realized. Therefore, both the exhaust pipe and the overflow pipe can be closed during the filling period. And even no exhaust pipe and/or overflow pipe needs to be provided on the vessel at all.
Although several preferred embodiments of the present invention have been described, the present invention may be used with other configurations. It will be appreciated by those skilled in the art that, the present invention could have many other embodiments, and changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims and equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009 1 0084016 | May 2009 | CN | national |
| 2009 2 0108011 U | May 2009 | CN | national |
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| Number | Date | Country | |
|---|---|---|---|
| 20100288774 A1 | Nov 2010 | US |
