Patent Application
20230211911
The present invention relates to the technical field of liquid filling apparatuses and, in particular, to a vacuum liquid-filling needle and a pressure relief valve thereof.
A liquid filling apparatus incorporates a liquid-filling needle as an important component mainly for quantitative extraction and injection of a liquid being filled, as widely seen in the pharmaceutical, chemical, food and beverage production industries.
A typical needle of this type is commonly used under an atmospheric pressure condition, or sometimes in a vacuum environment often with a low vacuum level. This is mainly because when the needle is placed in a high vacuum environment, a strong negative pressure therein tends to urge a liquid in a pipe in fluid communication with the needle to flow out of a tip of the needle, leading to contamination of the apparatus, or even degraded quality of filling. Even if the needle is provided with a certain sealing means, the liquid being filled would have to alternately expand and contract due to repeated switches between atmospheric and vacuum pressures. Consequently, the liquid tends to string at the needle tip, or even drip therefrom, affecting quality and stability of the filling process. Further, in addition to the negative pressure in the high vacuum environment, the liquid may also be driven by hydraulic power from a pump. As a consequence, it may exit the needle at an excessive speed, which tends to lead to splashes of the liquid being filled.
Chinese Patent Publication No. CN2546343Y mentions an anti-drip arrangement, which can be used with a liquid-filling needle to provide an anti-drip effect to the liquid being filled. It operates mainly by expansion and contraction of a rubber hose included therein, which provides some depressurization and “suck-back” effects on the liquid being filled. However, such depressurization and suck-back effects are provided in a relatively stochastic manner and considerably depend on variation of the rubber hose's elasticity over repeated use.
The present invention seeks to provide a vacuum liquid-filling needle and a pressure relief valve thereof, which can prevent efflux or dripping of the liquid being filled, provide depressurization, pressure stabilization, pressure stabilization and quantitative suck-back effects, and enable filling of a solution in vacuum environments.
To this end, the present invention provides a pressure relief valve comprising a valve body defining an internal cavity, in which a first slide valve and a second slide valve are disposed so as to be axially spaced apart from each other and both movable relative to the internal cavity. The valve body defines an inflow channel, an inflow port, an outflow port and an outflow channel. Each of the inflow channel and the outflow channel is formed by a blind bore, and both the inflow channel and the outflow channel axially extend along the valve body. The inflow channel is brought into communication with the internal cavity through the inflow port, and the outflow channel is brought into communication with the internal cavity through the outflow port. The inflow port and the outflow port divide the internal cavity axially into a first cavity, an inter-cavity passage and a second cavity. The first slide valve is configured to be maintained in an initial configuration by a first elastic force at a first position where the first slide valve resides on the inflow port to block communication of the inter-cavity passage with the inflow channel and to, when subjected to a first axial pressure from a solution to be filled, which is greater than the first elastic force, move axially against the first elastic force from the first position toward the first cavity to bring the inter-cavity passage into communication with the inflow channel. The second slide valve is configured to be maintained in the initial configuration by a second elastic force at a second position where the second slide valve blocks communication of the inter-cavity passage between the first and second slide valves with the outflow channel and to, when subjected to a second axial pressure from the solution to be filled, which is greater than the second elastic force, move axially within the internal cavity against the second elastic force from the second position toward the second cavity to bring the inter-cavity passage between the first and second slide valves into communication with the outflow channel.
Preferably, the first slide valve may be further configured to, when the first axial pressure from the solution to be filled is below the first elastic force or disappears, return to the first position under an action of the first elastic force, and the second slide valve may be further configured to, when the second axial pressure from the solution to be filled is below the second elastic force or disappears, return to the second position under an action of the second elastic force.
Preferably, a damping aperture may be provided in a wall of the first cavity so as to bring the outflow channel into communication with the first cavity.
Preferably, the pressure relief valve may further comprise a first securing member and a second securing member, with the internal cavity having a third end and a fourth end, the first securing member fixed at the third end of the internal cavity, the second securing member fixed at the fourth end of the internal cavity, wherein: a first elastic member for providing the first elastic force is provided in the first cavity so as to abut against the first slide valve at one end and against the first securing member at a further end; and a second elastic member for providing the second elastic force is provided in the second cavity so as to abut against the second slide valve at one end and against the second securing member at a further end.
Preferably, the first slide valve may comprise a first slide valve body comprising a hollow first enclosing post extending axially within the first cavity, the first elastic member accommodated in the first enclosing post, and the second slide valve may comprise a second slide valve body comprising a hollow second enclosing post extending axially within the second cavity, the second elastic member accommodated in the second enclosing post.
Preferably, the first securing member may define a first groove for receiving the first enclosing post, and the second securing member may define a second groove for receiving the second enclosing post.
Preferably, a first protrusion may extend from the first groove toward the first slide valve, and the further end of the first elastic member is sleeved over the first protrusion, and a second protrusion may extend from the second groove toward the second slide valve, the further end of the second elastic member is sleeved over the second protrusion.
Preferably, a damping aperture may be provided in a wall of the first cavity so as to bring the outflow channel into communication with the first cavity, the damping aperture spaced from the first position by a distance that is greater than a distance from an open end of the first enclosing post to a bottom of the first groove.
Preferably, the valve body may be provided thereon with a first valve seat and a second valve seat, the first valve seat configured to maintain the first slide valve at the first position and block the first slide valve from approaching the second slide valve, the second valve seat configured to maintain the second slide valve at the second position and block the second slide valve from approaching the first slide valve.
Preferably, the valve body may be further provided therein with a suction aperture, through which the outflow channel comes into communication with the internal cavity, and the suction aperture is located between the outflow port and an outlet of the outflow channel.
Preferably, the first slide valve may be a piston or a diaphragm, and the second slide valve may also be a piston or a diaphragm.
Preferably, the first slide valve may be a piston with a bevel for enabling the solution to be filled to exert the first axial pressure on the piston.
Preferably, the pressure relief valve may further comprise exit apertures and an annular groove, wherein a number of the exit apertures is greater than that of the outflow channels, and the exit apertures communicate with the outflow channels through the annular groove.
The present invention also provides a needle for vacuum filling of a liquid comprising a needle shaft and a pressure relief valve. The pressure relief valve is disposed within the needle shaft at a first end thereof, and the needle shaft is able to connect at a second end thereof to a pipe for supplying a solution to be filled. The pressure relief valve is as defined above. The inflow channel is open at a location closer to the second end of the needle shaft, and the outflow channel is open at a location closer to the first end of the needle shaft.
Preferably, the pressure relief valve may be connected to the needle shaft by an interference fit or threadedly.
Preferably, a dispensing head may be provided at the first end of the needle shaft.
Preferably, the dispensing head may comprise a dispensing port having a cross-section in the shape of a square, a rectangle or circle, the square having a side length in the range of 10 mm to 200 mm, the rectangle having a length in the range of 10 mm to 400 mm and a width in the range of 0.05 mm to 200 mm, the circle having a diameter in the range of 10 mm to 200 mm.
Preferably, the dispensing head may be detachably connected to or integral with the needle shaft.
Preferably, the needle shaft may be provided at the second end thereof with an adapter for connecting to the pipe for supplying the solution to be filled, and the adapter may be connected to the needle shaft by an interference fit or threadedly.
Preferably, the adapter may be a quick-connect connector or a threaded connector.
The present invention provides the following benefits over the prior art: according to the present invention, through providing the pressure relief valve within the needle shaft at the second end thereof, accidental efflux of the solution being filled that may occur under a negative vacuum pressure, as well as splashing of the solution that may occur under a high negative vacuum pressure, can be avoided, and depressurization and pressure stabilization effects can be provided during filling of the solution. In particular, when filling of the liquid is stopped and an output pressure in the solution in the needle is eliminated, the elastic members in the pressure relief valve enable restoration of an internal structure of the pressure relief valve. This allows quantitative suction of the solution, avoiding it from stringing at the dispensing port of the liquid-filling needle. In this way, the filling process can be conducted in a more stable and more controllable manner, without the problems including environmental contamination due to efflux or dripping of the liquid being filled and variation in quality. Further, dripping caused by repeated vacuuming in repeated filling cycles of the liquid-filling needle can be addressed, and improved filling accuracy and quality can be achieved, making it very suitable for use in precise filling in environments with high vacuum levels.
In these figures,
1 denotes an adapter; 2, a needle shaft; 3, a pressure relief valve; 4, a dispensing head; 21, a first end; 22, a second end; 30, a valve body; 31, a piston; 32, a diaphragm; 33, an inflow channel; 34, an inflow port; 35, an outflow port; 36, a damping aperture; 37, an outflow channel; 38, an exit aperture; 39, an annular groove; 300, an inter-cavity passage; 301, a first securing member; 302, a second securing member; 391, a first compression spring; 392, a second compression spring; 310, a piston body; 311, a first cavity; 312, a piston seat; 313, a first enclosing post; 314, a first protrusion; 315, a bevel; 320, a diaphragm body; 321, a second cavity; 322, a diaphragm seat; 323, a second enclosing post; 324, a second protrusion; 371, a suction aperture; 41, a flat dispensing head; 42, a flared dispensing head; and 411 and 421, dispensing ports.
Objects, aspects and advantages of the present invention will become more apparent upon reading the following description of embodiments thereof set forth with reference to the accompanying drawings.
As used herein, the terms “internal”, “external”, “above”, “under” and the like are for illustrative purposes only and not intended as the only possible implementation. As used herein, the term “axial” refers to the direction of a center axis of a hydraulic valve. As used herein, the term “initial configuration” refers to a configuration where the filling of a solution has not started yet, with a pressure relief valve remaining inoperative.
In an embodiment of the present invention, there is provided a vacuum liquid-filling needle, which includes an adapter 1, a needle shaft 2 and a pressure relief valve 3. As shown in
In this embodiment, as shown in
The valve body 30 defines an inflow channel 33, an inflow port 34, an outflow port 35, a damping aperture 36 and an outflow channel 37. The inflow channel 33 is provided by a blind bore for flowing therein of the solution to be filled, which extends axially along the valve body 30. Preferably, a plurality of inflow channels 33 are provided evenly around a circumference of the valve body 30. This embodiment is not limited to any particular number of inflow channels 33, or any particular number of inflow ports 34, and each of the numbers may be, for example, one, two, four, five, six, eight, or ten. In the embodiment shown in
Equally, the outflow channel 37 is provided by a blind bore for flowing out therefrom of the solution to be filled, which extends axially along the valve body 30. The pressure relief valve further includes an exit aperture 38 in communication with the outflow channel 37. The outflow channel 37 is open at a location closer to the first end 21 of the needle shaft 2. The outflow port 35 is formed also in the wall of the internal cavity so as to bring the outflow channel 37 into communication with the internal cavity. This embodiment is not limited to any particular number of outflow ports 35, or any particular number of outflow channels 37, or any particular number of exit apertures 38, and each of the numbers may be, for example, one, two, four, five, six, eight, or ten. Preferably, a plurality of outflow channels 37 are provided evenly around the circumference of the valve body 30. The number of outflow ports 35 and the number of exit apertures 38 may be the same as that of outflow channels 37. In this case, outlets of the outflow channels 37 may be brought into direct communication with the respective exit apertures 38. The number of exit apertures 38 may be different from, and preferably greater than, the number of outflow channels 37, in order to enable rapid efflux of the solution to be filled. In the embodiment shown in
The piston 31 is configured to be maintained in an initial configuration by a first elastic force at a first position where it resides over the inflow ports 34 to block communication between the inter-cavity passage 300 and the inflow channels 33. When subjected to a first axial pressure from the solution to be filled, which is greater than the first elastic force, the piston 31 will axially move against the action of the first elastic force from the first position toward the first cavity 311, bringing the inter-cavity passage 300 into communication with the inflow channels 33. When the first axial pressure from the solution to be filled drops below the first elastic force or disappears, the piston 31 will return to the first position under the action of the first elastic force, where it will again reside on the inflow ports 34 and block communication between the inter-cavity passage 300 and the inflow channels 33. In a preferred embodiment, the first position is where the inflow ports 34 come into communication with the inter-cavity passage 300. The diaphragm 32 is configured to be maintained in the initial configuration by a second elastic force at a second position where it blocks communication between the inter-cavity passage 300 between the piston 31 and the diaphragm 32 and the outflow channels 37. When subjected to a second axial pressure from the solution to be filled, which is greater than the second elastic force, the diaphragm 32 will axially move in the internal cavity against the action of the second elastic force from the second position toward the second cavity 321, bringing the inter-cavity passage 300 between the piston 31 and the diaphragm 32 into communication with the outflow channels 37. Likewise, when the second axial pressure from the solution to be filled drops below the second elastic force or disappears, the diaphragm 32 will return to the second position under the action of the second elastic force, where it will again block communication between the inter-cavity passage 300 between the piston 31 and the diaphragm 32 and the outflow channels 37. In a preferred embodiment, the second position lies between the first position and the outflow ports 35. The first axial pressure may be equal to the second axial pressure or not.
In this embodiment, as shown in
The pressure relief valve 3 further includes a first valve seat and a second valve seat. The first valve seat is configured to maintain the first slide valve at the first position and block the first slide valve from approaching the second slide valve. The second valve seat is configured to maintain the second slide valve at the second position and block the second slide valve from approaching the first slide valve. In this embodiment, the first position lies where the inflow ports 34 come into communication with the inter-cavity passage 300, and the second position is between the first position and the outflow ports 35. The first valve seat is a piston seat 312, and the second valve seat is a diaphragm seat 322. The piston seat 312 is configured to block the piston 31 from approaching the diaphragm 32, and the diaphragm seat 322 is configured to block the diaphragm 32 from approaching the piston 31. Specifically, the piston seat 312 is a first step defined in the valve body 30, and the first step has a shape matching with that of the piston 32. The diaphragm seat 322 is a second step defined in the valve body 30, and the second step has a shape matching with that of the diaphragm 32. Further, as shown in
With combined reference to
With combined reference to
The damping aperture 36 is provided in a wall of the first cavity 311 so as to bring the outflow channels 37 into communication with the first cavity 311. The damping aperture 36 is provided to enable a stable pressure in the first cavity 311 between the piston 31 and the first securing member 301 while the piston 31 is moving. Preferably, a distance between the damping aperture 36 and the first position is greater than a distance between the open end of the first enclosing post 313 and the bottom of the first groove in order to prevent the piston 31 from blocking the damping aperture 36.
Additionally, a suction aperture 371 is provided in a wall of the second cavity 321 so as to bring the outflow channels 37 into communication with the second cavity 321. The suction aperture 371 is configured to allow discharge of the solution that is sucked back into the second cavity 321. After the diaphragm 32 returns to the second position, the solution to be filled will flow back into an internal cavity defined by the diaphragm 32 and the second securing member 302. If this cavity is not emptied, the diaphragm 32 will not be able to move toward the second securing member 302. In order to avoid this, the suction aperture 371 is provided in the wall of the second cavity 321. Preferably, the suction aperture 371 is provided at the end of the second securing member 302 proximal to the diaphragm 32.
During use of the pressure relief valve 3 according to this embodiment, the solution to be filled flows to the inflow ports 34 through the inflow channels 33 in the pressure relief valve 3 and exerts a first force on the piston 31. When the first force increases and overcomes the first elastic force, the piston 31 moves toward the first securing member 301 into the first cavity 311, bringing the inflow ports 34 into communication with the inter-cavity passage 300. As a result, the solution to be filled enters the inter-cavity passage 300. The solution to be filled in the inter-cavity passage 300 then exerts a second force on the diaphragm 32. When the second force increases and overcomes the second elastic force, the diaphragm 32 moves toward the second securing member 302 into the second cavity 321, bringing the outflow ports 35 into communication with the inter-cavity passage 300. As a result, the solution to be filled enters the outflow channel 37 and finally flows out from the exit apertures 38. Once the supply of the solution to the pressure relief valve 3 is cut off, the second force on the diaphragm 32 will drop below the second elastic force, and the diaphragm 32 will move toward the piston 31 and stay at the second position, blocking communication of the inter-cavity passage 300 between the piston 31 and the diaphragm 32 with the outflow ports 35. Upon the first force on the piston 31 dropping below the first elastic force, the piston 31 will move toward the diaphragm 32 and stay at the first position, blocking communication between the inflow ports 34 and the inter-cavity passage 300.
In this embodiment, the axial pressures from the solution are balanced with the elastic forces of the first and second elastic members, and a throttling effect is provided within the pressure relief valve 3. As a result, the solution to be filled is depressurized and prevented from being jetted from the needle shaft 2 when in a vacuum environment. In addition, when the piston 31 is moving toward the first securing member as a result of the outflow channels 37 being brought into communication with the damping aperture 36, the first cavity 311 is depressurized through the outflow channels 37. Additionally, a pressure at the exit apertures 38 is fed back, through the outflow channels 37, to the first cavity 311 and hence to the piston 31. Therefore, the use of the damping aperture 36 enables a stable output pressure of the solution to be filled during axial reciprocation of the piston 31. Once the filling is stopped, the liquid in the supply pipe will be totally depressurized, and the piston 31 and the diaphragm 32 will be restored to the first and second positions by the first and second elastic forces, respectively. At the same time as the restoration, the solution will be sucked back through the outflow ports 35, avoiding it from stringing at a dispensing tip of the liquid-filling needle. In this way, dripping caused by repeated vacuuming in repeated filling cycles of the liquid-filling needle can be greatly reduced, and improved filling accuracy and quality can be achieved.
More preferably, a dispensing head in any of various shapes such as flat, cuboid, torus-like, flared and the like may be provided at the first end 21 of the needle shaft 2. The dispensing head 4 may have a dispensing port with a cross-sectional shape which may be square, rectangular, circular, etc. In case of a square cross-section, it is preferred to have a side length in the range of 10-200 mm. In case of a rectangular cross-section, it is preferred to have a length in the range of 10-400 mm and a width in the range of 0.05-200 mm. In case of a circular cross-section, it is preferred to have a diameter in the range of 10-200 mm.
Thus, the vacuum liquid-filling needle provided in the present invention, which incorporates the special pressure relief valve, can prevent undesired accidental efflux of the liquid under a negative vacuum pressure while providing depressurization and pressure stabilization effects during filling of the liquid. When filling of the liquid is stopped and an output pressure in the liquid in the liquid-filling needle is eliminated, an internal structure of the pressure relief valve can be restored and quantitative suction of the liquid can be achieved, avoiding it from stringing at the dispensing port of the liquid-filling needle. In this way, dripping caused by repeated vacuuming in repeated filling cycles of the liquid-filling needle can be addressed, and improved filling accuracy and quality can be achieved.
While the present invention has been described above in terms of preferred embodiments, it is not limited to the embodiments disclosed herein. Any person of skill in the art can make changes and modifications without departing from the scope or spirit of the invention. Accordingly, the true scope of the invention is intended to be as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202010549503.X | Jun 2020 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2021/073685 | 1/26/2021 | WO |
