A gas-liquid separation protection device for UV inkjet printing negative pressure gas circuit

Abstract

The utility model discloses a kind of gas-liquid separation protection devices for UV inkjet printing negative pressure gas path, belong to UV inkjet printing equipment technical field.Device includes shell with air inlet, gas outlet, first-stage separation cavity and secondary separation cavity are arranged in shell from bottom to top;Rotational flow flow guide component is equipped in first-stage separation cavity, shell bottom is equipped with liquid return port with one-way valve, baffle with air hole is equipped between two-stage separation cavity;Secondary separation cavity is equipped with the circular segment baffle of multiple layers staggered arrangement, bubble breaking protrusion is arranged on baffle.The utility model uses the two-stage structure of rotational flow centrifugal coarse separation cooperation baffling bubble breaking fine separation, not depending on buoyancy effect, can effectively handle the bubble and ink mixture generated by ink replacement emptying, separated ink can be automatically returned to ink box, avoid corrosive ink to invade downstream solenoid valve, negative pressure source, protect negative pressure gas path assembly.The device is independent component, can be directly concatenated in existing gas path, without modifying original equipment, reliable in operation, easy to maintain.

Description

Technical Field

[0001] This utility model specifically relates to a gas-liquid separation protection device for a negative pressure air path in UV inkjet printing. Background Technology

[0002] In existing UV inkjet printing systems, the secondary ink cartridge is connected to a negative pressure source via a negative pressure air tube to maintain a stable negative pressure inside the cartridge. The secondary ink cartridge typically contains a float-type level sensor to detect the ink level in real time. The control system uses the level signal to control the start and stop of the ink supply pump, ensuring a stable ink volume.

[0003] However, during ink replacement or emptying of secondary ink cartridges, the ink in the cartridge gradually empties, and the remaining ink mixes thoroughly with the gas entering the cartridge, forming a large amount of ink mixture containing air bubbles. At this time, the float-type liquid level sensor cannot function properly because the cavity is filled with the gas-liquid mixture. The float loses effective buoyancy support and becomes stuck, failing to trigger the liquid level warning. Under the continuous suction of negative pressure, the air bubble ink mixture is drawn into the negative pressure pipe through the negative pressure interface and then flows into the downstream solenoid valve and negative pressure source. Because UV ink has strong chemical corrosiveness, it can corrode and damage rubber or silicone components such as air pipe seals and solenoid valve diaphragms. Once the seals age and break due to corrosion, the negative pressure system will experience air leakage, unstable negative pressure fluctuations, and other malfunctions, directly affecting the ink supply stability of the printhead. In severe cases, it can also lead to the failure of the solenoid valve and the damage to the negative pressure pump, increasing equipment maintenance costs.

[0004] While existing technologies include negative pressure anti-backflow devices, these typically rely on a float rising in the liquid to block the air passage interface, thus preventing backflow of pure liquid. However, this type of structure is designed for pure liquid conditions, with the float dependent on the buoyancy of the pure liquid for propulsion. In the case of gas-liquid foam mixtures, the overall density of the mixture is much lower than that of the pure liquid, failing to provide sufficient buoyancy for the float to operate normally. Therefore, such anti-backflow devices cannot effectively address protection scenarios involving gas-liquid foam mixtures. Utility Model Content

[0005] In view of the defects of the existing technology, the technical problem to be solved by this utility model is to provide a gas-liquid separation protection device for the negative pressure gas path of UV inkjet printing.

[0006] A gas-liquid separation protection device for a negative pressure air circuit in UV inkjet printing includes a housing with a hollow cavity. The housing has an air inlet and an air outlet. The air inlet connects to the negative pressure interface of a secondary ink cartridge, and the air outlet connects to a negative pressure air pipe. The device is characterized by: a primary separation chamber and a secondary separation chamber arranged sequentially from bottom to top along the airflow direction within the housing; the air inlet is located at the lower part of the primary separation chamber, and the air outlet is located at the upper part of the secondary separation chamber; a swirling flow guide component is provided within the primary separation chamber; a liquid return port is provided at the bottom of the housing, and a one-way valve is installed at the liquid return port, allowing liquid to flow unidirectionally from inside the housing to the external secondary ink cartridge; a partition is provided between the primary and secondary separation chambers, and the partition has ventilation holes; at least two layers of staggered baffles are provided within the secondary separation chamber, forming a baffle channel between adjacent baffles that causes the gas to flow in a diversion direction, and several bubble-breaking protrusions are provided on the surface of each baffle.

[0007] In one embodiment, the swirling flow guiding component is a spiral guide vane, and the spiral lift angle of the spiral guide vane is 15°-30°.

[0008] In one embodiment, the vent is located off-center from the partition, causing the air outlet to deviate from the central axis of the housing.

[0009] In one embodiment, the baffle is in the shape of a cleft rim, and the notches of adjacent baffles are in opposite directions.

[0010] In one embodiment, the bubble-breaking protrusion is a conical or cylindrical structure.

[0011] In one embodiment, the bottom cross-section of the housing is funnel-shaped, wider at the top and narrower at the bottom, and the return port is located at the lowest point of the funnel-shaped bottom; the one-way valve is a spring-reset ball valve or a duckbill valve.

[0012] In one embodiment, the housing is made of a UV-resistant ink corrosion-resistant material, and the surface of the internal flow channels is treated with a hydrophobic coating or polishing.

[0013] In one embodiment, the top or side wall of the housing is provided with a transparent window for observing the internal liquid condition.

[0014] In one embodiment, a manual vent valve is provided on the top of the housing to release residual air pressure inside the housing.

[0015] In summary, the advantages of this utility model over the prior art are:

[0016] This invention uses a partition to divide the chamber into an independent primary separation chamber and a secondary separation chamber. The primary separation chamber uses a spiral swirling component to remove most of the liquid ink using centrifugal force, achieving coarse separation. The gas after coarse separation then enters the secondary separation chamber, where it forms an S-shaped deflection channel with the help of staggered baffles. The array of bubble-breaking protrusions on the baffles further impacts and breaks down residual microbubbles and fine droplets, capturing them. The coarse separation and fine bubble breaking work together to achieve a thorough gas-liquid separation, reducing the risk of liquid carryover on the gas outlet side. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of a gas-liquid separation protection device for a negative pressure gas path in UV inkjet printing according to one embodiment of the present invention.

[0018] Figure 2 One of the exploded views of a gas-liquid separation protection device for a negative pressure gas path in UV inkjet printing according to one embodiment of the present invention;

[0019] Figure 3 A second exploded view of a gas-liquid separation protection device for a negative pressure air path in UV inkjet printing, according to one embodiment of this utility model. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0021] like Figures 1 to 3 The present invention preferably provides a gas-liquid separation protection device for a negative pressure air path in UV inkjet printing, comprising a housing 1 having a hollow cavity, wherein the housing 1 is respectively provided with an air inlet 2 and an air outlet 3, the air inlet 2 being used to connect to the negative pressure interface of the secondary ink cartridge, and the air outlet 3 being used to connect to the negative pressure air pipe, characterized in that: a primary separation chamber 4 and a secondary separation chamber 5 are sequentially arranged from bottom to top along the airflow direction inside the housing 1, the air inlet 2 being located at the lower part of the primary separation chamber 4, and the air outlet 3 being located at the upper part of the secondary separation chamber 5; wherein, the A swirling flow guide component 6 is provided in the primary separation chamber 4. A liquid return port is provided at the bottom of the housing 1. A one-way valve 7 is installed at the liquid return port. The one-way valve 7 allows liquid to flow out of the housing 1 in one direction only to the external secondary ink cartridge. A partition 8 is provided between the primary separation chamber 4 and the secondary separation chamber 5. A vent hole is provided on the partition 8. At least two layers of baffles 9 are provided in the secondary separation chamber 5. A baffle channel 10 is formed between adjacent baffles 9 to cause the gas to flow in a turning direction. Several bubble-breaking protrusions 11 are provided on the surface of each baffle 9.

[0022] When this device is working, the negative pressure source is activated, and the air-bubble ink mixture in the secondary ink cartridge enters the primary separation chamber through the air inlet under the negative pressure suction, thus completing the two-stage separation and liquid reflux in sequence.

[0023] Specifically, when the gas-liquid mixture enters the primary separation chamber, it spirals upward along the inner wall of the chamber under the guidance of the swirling flow guide component. The ink droplets with higher density in the mixture are thrown towards the inner wall of the shell by centrifugal force, and after losing kinetic energy, they slide down the inner wall under the action of gravity and collect at the bottom of the shell; the gas with lower density rises along the central area of ​​the chamber and enters the secondary separation chamber through the vent holes on the partition, thus achieving coarse gas-liquid separation.

[0024] After the gas carrying residual microbubbles and fine droplets enters the secondary separation chamber, it flows along the baffle channel, repeatedly changing direction between the staggered baffles. Due to the inertial force generated by the change of direction, the bubbles and droplets in the gas flow repeatedly impact the surface of the baffles and the bubble-breaking protrusions on the surface. The bubbles burst, and the droplets adhere to the surface of the baffles. Under the action of gravity, they fall down the baffles step by step, eventually flowing back to the bottom of the primary separation chamber, thus achieving fine gas-liquid separation.

[0025] When the ink liquid collected at the bottom of the casing reaches a certain liquid column height, the hydraulic system pushes the one-way valve to open, and the liquid automatically flows out and back to the secondary ink cartridge. Under negative pressure operation, the one-way valve remains closed under the action of reverse pressure difference to prevent external gas from flowing back into the casing and to ensure the airtightness of the negative pressure system.

[0026] Finally, the clean gas after two-stage separation flows out from the outlet and enters the downstream negative pressure gas path, preventing corrosive ink from contacting components such as solenoid valves and negative pressure pumps.

[0027] Furthermore, the swirling flow guiding component 6 is a spiral guide vane, and the spiral helix angle of the spiral guide vane is 15°-30°.

[0028] Specifically, in this embodiment, the swirling flow guiding component is a spiral guide plate, which extends continuously spirally along the axial direction of the shell, with a spiral angle set to 15°-30°. The spiral angle directly determines the swirling intensity and airflow resistance: if the angle is less than 15°, the spiral flow path is too steep, the airflow resistance increases significantly, resulting in excessive pressure loss in the negative pressure system and affecting the negative pressure stability of the secondary ink cartridge; if the angle is greater than 30°, the airflow rotation radius is large, the number of rotations is small, the centrifugal force is insufficient, and the dehydration effect on low-density bubble ink mixtures is poor. This embodiment uses an angle range of 15°-30°, which, while ensuring that the air resistance meets the rated requirements of the UV inkjet negative pressure system, allows the gas-liquid mixture to obtain sufficient centrifugal acceleration, fully throwing the droplets towards the cavity wall, adapting to the low-concentration bubble conditions during ink replacement and evacuation, and achieving efficient primary dehydration.

[0029] The outer edge of the spiral guide vane is connected to the inner wall of the shell by several radial support ribs, which are evenly distributed along the circumference. The spiral guide vane is fixed to the inside of the shell by the outer ring support ribs, and the inner ring is suspended to form a central airflow channel.

[0030] A 1-3mm gap is maintained between the outer edge of the spiral guide vane and the inner wall of the housing to avoid assembly friction interference and minimize liquid short-circuiting escape from the gap. The spiral guide vane is a continuously twisted thin sheet made of PTFE, ETFE, or 316L stainless steel resistant to UV ink corrosion. The surface of the blade can be treated with a liquid-repellent coating to reduce ink adhesion to the wall. The inner side of the spiral guide vane forms a central gas rising channel, and the spiral guide vane and the inner wall of the housing constitute a spiral rising flow channel. The gas-liquid mixture moves upward along the spiral flow channel and is forced to rotate in a circular motion, while the droplets are thrown towards the inner wall of the housing by centrifugal force.

[0031] Furthermore, the vent is located off-center from the partition 8, causing the air outlet to deviate from the central axis of the housing 1.

[0032] Specifically, in this embodiment, the vent holes on the baffle are located off-center from the geometric center of the baffle, causing the outlet channel of the primary separation chamber to deviate from the central axis of the shell. If the vent holes were centrally located, the high-speed upward airflow from the center of the primary separation chamber would rush vertically upward into the secondary separation chamber. The airflow would easily pass directly through the gaps between the baffles and would not be able to fully contact the baffle surface, resulting in a decrease in the secondary bubble-breaking effect. This embodiment uses an eccentric vent hole design, causing the primary outlet airflow to cut into the secondary separation chamber along the offset direction. The airflow first impacts the surface of the upper baffle, is forced to diffuse along the surface, and then flows along the baffle channel. This effectively prolongs the residence path and residence time of the airflow in the secondary chamber, increases the probability of collision between bubbles and bubble-breaking protrusions, and significantly improves the separation efficiency of the secondary baffle bubble-breaking process.

[0033] Furthermore, the baffle plate 9 is in the shape of a cleft and right circle, and the notches of two adjacent baffle plates 9 are in opposite directions.

[0034] Specifically, in this embodiment, the baffle plate has a segmental shape, formed by cutting off a corner of a complete circular plate to create an arc-shaped segment. The outer edge of the baffle plate matches the inner wall of the shell, and the cut-off arc-shaped area forms a fluid flow gap. The gaps of adjacent baffle plates are arranged in opposite directions at 180°. The opposite staggered gaps of adjacent baffle plates create a continuous S-shaped reversal flow channel. When the gas flows through, it will undergo multiple approximately 180° changes in flow direction. Due to inertia, bubbles and droplets in the airflow continuously impact the solid surface of the baffle plate during these turns. Compared with flat baffles or single-layer baffle structures, the reversed segmental arrangement maximizes the number of airflow turns and the flow path length within a limited cavity height, increasing the probability of bubble collision and breakage, and enhancing the effect of secondary fine separation.

[0035] Furthermore, the bubble-breaking protrusion 11 has a conical or cylindrical structure.

[0036] Specifically, in this embodiment, the bubble-breaking protrusions are conical or cylindrical structures, with the protruding ends facing the direction of the airflow. Smooth baffles rely solely on planar impact to break bubbles. For small bubbles with high surface tension, planar impact is insufficient to effectively break them. This embodiment provides conical or cylindrical bubble-breaking protrusions on the baffle surface, effectively adding numerous impact edges and sharp points within the flow channel. When tiny bubbles in the airflow pass over the protrusions, they are cut by the edges and punctured by the tips, rapidly breaking their surface tension and causing them to break. This effectively improves the ability to break small bubbles, further reducing the liquid content of the outlet gas and improving separation accuracy.

[0037] Furthermore, the bottom cross-section of the housing 1 is funnel-shaped, wider at the top and narrower at the bottom, and the return port is located at the lowest point of the funnel-shaped bottom; the one-way valve 7 is a spring-reset ball valve or a duckbill valve.

[0038] Specifically, the funnel-shaped bottom forms a converging liquid collection structure, where the separated ink, under the influence of gravity, all converges towards the return port at the lowest point, eliminating dead zones and preventing ink residue from drying and clogging the flow channels at the bottom of the cavity. When using a spring-return ball valve or duckbill valve, the opening pressure can be precisely controlled by the spring force: when the liquid column pressure at the bottom of the housing is greater than the spring return force, the valve opens, and the liquid automatically flows back; during negative pressure operation, the spring force and the negative pressure difference work together to keep the valve sealed, ensuring smooth liquid recovery and reliably preventing gas backflow, thus ensuring stable pressure in the negative pressure gas path.

[0039] Furthermore, the housing 1 is made of a UV-resistant ink corrosion-resistant material, and the surface of the internal flow channel is treated with a hydrophobic coating or polishing.

[0040] Specifically, UV inks contain active monomers and photoinitiators, exhibiting strong chemical corrosivity. Ordinary materials are easily corroded, leading to problems such as swelling, cracking, and aging. Using UV-resistant materials for the housing ensures long-term resistance to ink erosion, significantly extending the device's lifespan. The hydrophobic coating or polishing treatment of the internal flow channels reduces ink surface adhesion, minimizing ink residue and preventing ink from drying and clogging the flow channels and vents. It also facilitates later cleaning and maintenance, reducing maintenance difficulty.

[0041] Furthermore, the top or side wall of the housing 1 is provided with a transparent viewing window 13 for observing the internal liquid state.

[0042] Specifically, closed-type separation devices cannot be directly assessed for their internal operating status, requiring daily inspections to be performed by disassembling the machine, resulting in high maintenance costs. By installing a transparent viewing window, operators can directly observe the liquid level inside the casing, the bubble separation effect, and the condition of components during equipment operation. This allows them to determine whether the device is working properly without disassembling it, facilitating daily inspections and troubleshooting, and enabling the timely detection of problems such as blockages and abnormal liquid accumulation, thereby reducing maintenance costs and downtime risks.

[0043] Furthermore, a manual exhaust valve 12 is provided on the top of the housing 1 to release residual air pressure inside the housing.

[0044] Specifically, since the device operates under negative pressure for extended periods, residual negative pressure remains inside the casing after shutdown. Direct disassembly can lead to ink splattering and difficulty in opening the casing. Before shutting down the equipment for maintenance or disassembling the device, manually opening the manual exhaust valve allows the casing to connect with the outside atmosphere, releasing residual pressure. This enables safe and convenient disassembly for internal cleaning or component repair, significantly improving the safety and convenience of maintenance operations.

[0045] The foregoing has shown and described the basic principles and main features of this utility model, as well as its advantages. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A gas-liquid separation protection device for a negative pressure air circuit in UV inkjet printing, comprising a housing (1) having a hollow cavity, wherein the housing (1) is provided with an air inlet (2) and an air outlet (3), the air inlet (2) being used to connect to the negative pressure interface of a secondary ink cartridge, and the air outlet (3) being used to connect to a negative pressure air pipe, characterized in that: The housing (1) is provided with a primary separation chamber (4) and a secondary separation chamber (5) arranged sequentially from bottom to top along the airflow direction. The air inlet (2) is located at the lower part of the primary separation chamber (4), and the air outlet (3) is located at the upper part of the secondary separation chamber (5). The primary separation chamber (4) is provided with a swirling flow guide component (6). The bottom of the housing (1) is provided with a liquid return port. A one-way valve (7) is installed at the liquid return port. The one-way valve (7) allows liquid to flow out unidirectionally from the housing (1) to the external secondary ink cartridge. A partition (8) is provided between the primary separation chamber (4) and the secondary separation chamber (5). A vent hole is provided on the partition (8). The secondary separation chamber (5) is provided with at least two layers of staggered baffles (9). A baffle channel (10) is formed between adjacent baffles (9) to cause the gas to turn and flow. Several bubble-breaking protrusions (11) are provided on the surface of each baffle (9).

2. The gas-liquid separation protection device for a negative pressure gas path in UV inkjet printing according to claim 1, characterized in that: The swirling guide component (6) is a spiral guide plate, and the spiral helix angle of the spiral guide plate is 15°-30°.

3. The gas-liquid separation protection device for a negative pressure gas path in UV inkjet printing according to claim 1, characterized in that: The vent is located off-center from the partition (8), causing the air outlet to deviate from the central axis of the housing (1).

4. The gas-liquid separation protection device for a negative pressure gas path in UV inkjet printing according to claim 1, characterized in that: The baffle (9) is in the shape of a circle, and the notches of two adjacent baffles (9) are in opposite directions.

5. The gas-liquid separation protection device for a negative pressure gas path in UV inkjet printing according to claim 1, characterized in that: The bubble-breaking protrusion (11) has a conical or cylindrical structure.

6. The gas-liquid separation protection device for a negative pressure gas path in UV inkjet printing according to claim 1, characterized in that: The bottom cross-section of the housing (1) is funnel-shaped with a larger top and a smaller bottom, and the return port is located at the lowest point of the funnel-shaped bottom; the one-way valve (7) is a spring-reset ball valve or a duckbill valve.

7. A gas-liquid separation protection device for a negative pressure gas path in UV inkjet printing according to claim 1, characterized in that: The housing (1) is made of a UV-resistant ink corrosion resistant material, and the surface of the internal flow channel is treated with a hydrophobic coating or polishing.

8. The gas-liquid separation protection device for a negative pressure gas path in UV inkjet printing according to claim 1, characterized in that: The shell (1) has a transparent window (13) on its top or side wall for observing the internal liquid state.

9. A gas-liquid separation protection device for a negative pressure gas path in UV inkjet printing according to claim 1, characterized in that: The top of the housing (1) is provided with a manual exhaust valve (12) for releasing residual air pressure inside the housing.

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