Double-bottle body intravenous infusion system with adjustable mechanical constant flow valve

Abstract

The invention discloses a double-bottle intravenous infusion system with an adjustable mechanical constant flow valve, which comprises a compressed air power unit, a mechanical constant flow adjustable valve and an air pressure driving infusion unit, and realizes passive constant-speed infusion through a pure mechanical structure. The compressed air power unit provides an independent high-pressure air source, the mechanical constant-flow adjustable valve is of a three-level structure of pressure reduction and stabilization, laminar flow stabilization and pressure compensation feedback, fluctuation air pressure is converted into constant air flow, and the air pressure driving liquid conveying unit achieves constant-speed liquid output with gas-liquid isolation through a double-layer bottle body structure. And mechanical blockage alarm and overvoltage protection are built in. The device does not need electric power, is high in flow velocity precision, high in stability, free of pollution risk due to gas-liquid isolation, high in system integration degree, portable and long-acting, can support several-hour infusion through single inflation, is suitable for non-electric or non-electric medical scenes such as battlefield first aid, disaster rescue and MRI rooms, and can also be extensively applied to the fields of wound flushing, contrast agent injection and the like.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and more specifically to a dual-bottle intravenous infusion system with an adjustable mechanical constant flow valve. Background Technology

[0002] Intravenous infusion is an indispensable method of drug administration in clinical treatment, and its core requirement is to achieve accurate and stable drug delivery. Current intravenous infusion technologies mainly rely on gravity or electric drive, which have significant drawbacks in special environments: First, gravity infusion: the flow rate is greatly affected by the fluid level, patient position, and tubing resistance, making precise control and stable maintenance difficult, and it cannot perform pressurized rapid infusion, failing to meet the needs of emergency scenarios; Second, electric infusion pumps: while achieving precise flow rate control, they must rely on a continuous power supply or battery power, resulting in a significant decrease in reliability in harsh, mobile, or power-constrained environments, and are also subject to electromagnetic interference, making them unsuitable for special scenarios with strict electromagnetic environment requirements, such as MRI rooms; Third, existing portable pressurized infusion devices: mostly use manual squeezing of the airbag or spring-driven mechanical actuation. Manual pressurization suffers from rapid pressure decay and unstable flow rate; spring-driven devices are mostly timed release structures, making it difficult to achieve a wide range of real-time adjustable constant flow rates, and lacking a precise mechanical feedback flow stabilization mechanism, thus compromising infusion accuracy.

[0003] Therefore, the market urgently needs a portable intravenous infusion solution that does not rely on external power, can provide a stable and adjustable flow rate, and is safe and reliable, to meet the infusion needs of emergency rescue and special medical environments. Summary of the Invention

[0004] The purpose of this invention is to provide a stable, reliable, reusable, and easy-to-operate dual-bottle intravenous infusion system with an adjustable mechanical constant flow valve to overcome the shortcomings of existing technologies.

[0005] The present invention achieves the above objectives by adopting the following technical solution: a dual-bottle intravenous infusion system with an adjustable mechanical constant flow valve, characterized in that it comprises a compressed air power mechanism, a mechanical constant flow adjustable valve and a pneumatically driven infusion mechanism that are fluidly connected in sequence, thereby achieving passive constant-speed intravenous infusion through a purely mechanical structure;

[0006] The compressed air power mechanism provides the system with an independent and clean high-pressure air source, including a high-pressure air tank, a precision pressure gauge, a manual switch valve, a safety valve, a quick inflation interface, and a pressure stabilizing buffer chamber. The pressure stabilizing buffer chamber is located downstream of the manual switch valve and is used to smooth airflow pulsations.

[0007] The mechanical constant flow adjustable valve is connected between the compressed air power mechanism and the pneumatically driven infusion mechanism, converting fluctuating air pressure into a constant gas flow rate.

[0008] The pneumatically driven infusion mechanism is used to linearly convert a constant gas flow rate into a constant liquid flow rate output. It includes a double-layer bottle structure and a mechanical blockage alarm. The double-layer bottle structure achieves physical isolation between gas and liquid, and the mechanical blockage alarm is used for pressure alarm and pressure relief protection when the pipeline is blocked.

[0009] Furthermore, in the double-layer bottle structure of the pneumatically driven infusion mechanism, the outer layer is a rigid / semi-rigid transparent medical-grade polycarbonate shell, and the inner layer is a disposable medical PVC or TPE flexible storage bag, with a uniform gap between the flexible storage bag and the inner wall of the shell.

[0010] Furthermore, the mechanical blockage alarm is installed on the top of a transparent medical-grade polycarbonate shell and includes a safety diaphragm with a preset rupture pressure and a linked red warning bar. When the pipeline blockage causes the air chamber pressure to exceed 0.3 atm, the diaphragm ruptures, the warning bar pops out and releases pressure.

[0011] Furthermore, the flexible storage bag is connected to a standard infusion line via a Luer connector, and the air inlet of the transparent medical-grade polycarbonate shell is connected to the outlet of the mechanical constant flow adjustable valve via a pipeline.

[0012] Furthermore, the mechanical constant flow adjustable valve adopts a three-level control architecture to convert fluctuating gas pressure into constant gas flow, including a precision pressure reduction and stabilization module, a laminar flow stabilization and flow selection module, and a feedback pressure compensation module.

[0013] The precision pressure reducing and stabilizing module, as the first-level control module, includes an air intake chamber and a pressure reducing diaphragm, a pressure regulating spring, and a valve core installed inside it. The pressure regulating spring is connected to the valve core. Regardless of how the pressure of the upstream air tank changes within the range of 10-3 atm, the diaphragm senses the outlet pressure and dynamically adjusts the valve core opening to stabilize the output pressure P1 at the preset value (2.0±0.1 atm). The preload of the pressure regulating spring can be finely adjusted by an external screw.

[0014] The laminar flow stabilization and flow selection module, as the second-level control module, includes a rotatable selection valve core, a flow selection knob, a dial, and a fine-tuning needle valve. The selection valve core is machined with multiple sets of parallel precision capillary channels. Rotating the knob drives the valve core to select the corresponding flow channel, and the dial marks the corresponding liquid flow rate.

[0015] The feedback pressure compensation module, as the third-level control module, includes a flexible pipeline, a reference gas chamber, a compensation diaphragm, and a feedback lever. The reference gas chamber is pre-charged with a fixed pressure P_ref higher than atmospheric pressure. One side of the compensation diaphragm senses the capillary outlet pressure P2', while the other side is controlled by the force exerted by P_ref and the end force of the feedback lever. Changes in P2' will cause the diaphragm to deform, which will amplify and drive the conical valve core to move through the lever, adjust the local resistance, compensate for flow fluctuations, and ultimately output a constant gas flow rate Q_gas.

[0016] The fine-tuning needle valve is linked to an eccentric cam mechanism to achieve continuous and precise adjustment of ±20% within each gear position.

[0017] Furthermore, the precision capillary is made of fused silica or stainless steel and has three sets of core flow channels: low flow rate (d=0.08mm, L=50mm) corresponding to a liquid flow rate of 1-5ml / h; medium flow rate (d=0.12mm, L=40mm) corresponding to a liquid flow rate of 10-50ml / h; and high flow rate (d=0.18mm, L=30mm) corresponding to a liquid flow rate of 60-150ml / h.

[0018] The beneficial effects that can be achieved by adopting the above-mentioned technical solution in this invention are:

[0019] This invention employs an intravenous infusion system primarily composed of a compressed air power mechanism, a mechanical constant-flow adjustable valve, and a pneumatically driven infusion mechanism. It achieves passive, constant-speed infusion through a purely mechanical structure, requiring no electricity or batteries, making it suitable for extreme environments and medical scenarios without or without electricity. Flow rate control is achieved through purely mechanical principles, remaining constant within a set range regardless of the slow decrease in air source pressure. Prototype testing shows that flow rate fluctuations are less than ±10% as the air source pressure decreases from 10 atm to 3 atm. Physical isolation between gas and liquid eliminates the risk of drug contamination. Built-in mechanical blockage alarm and overpressure protection are included; the blockage alarm triggers within 2 seconds when the pipeline pressure exceeds the threshold. The system boasts high integration, supporting several hours of infusion with a single inflation, meeting transport and emergency needs. Besides intravenous infusion, with slight modifications, it can be applied to medical scenarios requiring portable, constant-flow fluid delivery, such as wound irrigation, contrast agent injection, and enteral nutrition infusion. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention.

[0021] Figure 2 This is a schematic diagram of the pressure reducing chamber structure of the mechanical constant flow valve of the present invention.

[0022] Figure 3 This is a capillary structure diagram of the mechanical constant flow valve of the present invention.

[0023] Figure 4 This is a structural diagram of the pressure compensation membrane of the present invention.

[0024] Figure 5 This is a schematic diagram of the pneumatically driven infusion mechanism of the present invention.

[0025] Explanation of reference numerals in the attached drawings: 1. Compressed air power mechanism; 2. Mechanical constant flow adjustable valve; 2-1. Inlet chamber; 2-2. Pressure reducing diaphragm; 2-3. Pressure regulating spring; 2-4. Valve core; 2-5. Rotatable selectable valve core; 2-6. Flow selection knob; 2-7. Precision capillary flow channel; 2-8. Compensation diaphragm; 2-9. Feedback lever; 3. Pneumatically driven infusion mechanism; 3-1. Housing; 3-2. Constant flow air source inlet; 3-3. Liquid storage bag; 3-4. Connector. Detailed Implementation

[0026] In the description of this invention, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this invention.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Thus, the use of "first" and "second" to define a feature may explicitly or implicitly include one or more of that feature, and in the description of this invention, "at least" means one or more, unless otherwise explicitly specified.

[0028] In this invention, unless otherwise explicitly specified and limited, the terms "assembly," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection; they can refer to a direct connection or a connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] In this invention, unless otherwise specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "below," and "over" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Above," "below," and "below" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0030] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings, making the technical solution and beneficial effects of the present invention clearer and more explicit. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0031] like Figures 1-5 As shown, this invention is a dual-bottle intravenous infusion system with an adjustable mechanical constant flow valve. It is a three-stage energy conversion and control device. The core logic is to convert the potential energy of pre-stored compressed air into constant and adjustable hydraulic energy output for the drug solution through a purely mechanical flow stabilization and adjustment mechanism. The system consists of three integrated units: a compressed air power mechanism 1, a mechanical constant flow adjustable valve 2, and a pneumatically driven infusion mechanism 3.

[0032] The compressed air power unit 1 provides the system with an independent, clean and stable high-pressure air source, including a high-pressure air tank, a precision pressure gauge, a manual switch valve, a safety valve, a quick-fill air interface and a pressure stabilizing buffer chamber.

[0033] High-pressure air storage tank: The core energy storage component, forged from 6061-T6 aluminum alloy or 304 stainless steel, with a working pressure of 10 atm (gauge pressure), a safety factor of ≥4, and a volume of 50 ml (after compression), corresponding to the storage of approximately 550 ml of atmospheric pressure air;

[0034] Precision pressure gauge: measuring range 0-15 atm, with a green working area (3-10 atm) on the dial for intuitive indication of gas source status;

[0035] Manual on / off valve: adopts a ball valve structure and is used to connect or disconnect the power output;

[0036] Safety valve: Mechanical diaphragm type, set to release pressure at 12 atm, providing overpressure protection;

[0037] Quick inflation interface: Equipped with a one-way valve, it supports quick inflation using a standard manual air pump or small air cylinder;

[0038] Pressure stabilizing buffer chamber: A small chamber located after the switching valve, used to initially suppress airflow pulsation.

[0039] The adjustable mechanical constant flow valve 2 is structurally designed with a three-stage control architecture to convert fluctuating gas pressure into a constant gas flow rate.

[0040] Level 1: Precision pressure reduction and stabilization module, consisting of an air inlet chamber 2-1, a pressure reducing diaphragm 2-2, a pressure regulating spring 2-3, and a valve core 2-4. Regardless of how the pressure in the upstream air tank changes within the range of 10-3 atm, the diaphragm senses the outlet pressure and dynamically adjusts the valve core opening to stabilize the output pressure P1 at a preset value (2.0±0.1 atm). The preload of the pressure regulating spring can be finely adjusted by an external screw.

[0041] Level 2: Laminar flow stabilization and flow selection module, including a rotatable selection valve core 2-5, a flow selection knob 2-6, a dial, and a fine-tuning needle valve. The selection valve core is internally machined with multiple sets of parallel precision capillary channels 2-7. The capillaries are made of fused silica or stainless steel with smooth inner walls. Three core channels are designed according to the Hagen-Poiseuille law. Rotating the knob drives the valve core to select the corresponding channel, and the dial marks the corresponding liquid flow rate. At the same time, the fine-tuning needle valve is linked by an eccentric cam to achieve continuous fine adjustment within ±20% of the gear position.

[0042] Level 3: Feedback pressure compensation module, consisting of flexible pipe, reference chamber, compensation diaphragm 2-8 and feedback lever 2-9. The reference chamber is pre-charged with a fixed pressure P_ref slightly higher than atmospheric pressure. One side of the compensation diaphragm senses the capillary outlet pressure P2', while the other side is controlled by the force of P_ref and the end of the feedback lever. Changes in P2' will cause the diaphragm to deform, which will amplify and drive the conical valve core to move, adjust local resistance, compensate for flow fluctuations, and finally output a constant gas flow rate Q_gas.

[0043] The pneumatically driven infusion mechanism 3 is used to linearly convert a constant gas flow rate Q_gas into a constant liquid flow rate Q_liq, and includes a double-walled bottle structure and a mechanical blockage alarm.

[0044] Double-layer bottle structure: The outer layer is a rigid / semi-rigid transparent medical-grade polycarbonate shell 3-1, forming a sealed driving air chamber, equipped with a constant flow air source inlet 3-2 and a mechanical blockage alarm trigger interface; the inner layer is a disposable flexible medical PVC or TPE storage bag 3-3 with a volume of 500ml, which is connected to the standard infusion line through aseptic welding or Luer connector 3-4. The flexible bag is suspended inside the shell, with a uniform gap between it and the inner wall of the shell to ensure uniform pressure.

[0045] Gas-liquid conversion principle: Constant flow gas Q_gas enters the driving gas chamber. The increase in gas volume per unit time, dV_gas / dt, is equal to Q_gas. The gas uniformly compresses the flexible bag, reducing its volume by dV_liq / dt. Since dV_gas / dt = dV_liq / dt, the liquid output flow rate Q_liq = Q_gas. The system is designed so that a gas flow rate of 1 ml / min corresponds to a liquid flow rate of 60 ml / h, enabling intuitive flow rate setting and reading.

[0046] Mechanical blockage alarm: Located at the top of the driving gas chamber, it includes a safety diaphragm with a preset rupture pressure and a linked red warning rod. When the infusion line is completely blocked, the pressure in the driving gas chamber rises. When it exceeds the 0.3 atm threshold, the diaphragm ruptures, and the high-pressure gas pushes the warning rod to pop out instantly, providing a visual alarm. At the same time, the gas is slowly released through the pressure relief hole to prevent excessive pressure.

[0047] System assembly:

[0048] 1. Compressed air power unit assembly: Connect the high-pressure air tank, precision pressure gauge, manual switch valve, safety valve, and quick air charging interface in sequence through pipelines. Connect the pressure stabilizing buffer chamber in series downstream of the manual switch valve. All connection parts are sealed with sealing gaskets to ensure no gas leakage.

[0049] 2. Mechanical constant flow adjustable valve assembly: The pressure reducing and stabilizing module, laminar flow stabilizing and flow selection module, and feedback pressure compensation module are sequentially integrated into the same valve body. The pressure reducing diaphragm is rigidly connected to the valve core. The pressure regulating spring is set above the pressure reducing diaphragm. The valve core, flow selection knob, and fine-tuning needle valve are linked through an eccentric cam mechanism. The compensation diaphragm is fixed to one end of the feedback lever, and the other end of the feedback lever is connected to the conical valve core. The reference air chamber is pre-charged to set the pressure P_ref.

[0050] 3. Assembly of pneumatically driven infusion unit: Insert the inner flexible storage bag into the outer polycarbonate shell, ensuring that the gap between the flexible bag and the inner wall of the shell is uniform, seal the shell, install the mechanical blockage alarm on the top of the shell, connect the inner flexible storage bag to the standard infusion pipeline through Luer connector, and connect the air inlet of the shell to the outlet of the mechanical constant flow adjustable valve through pipeline.

[0051] 4. Overall assembly: Connect the outlet of the pressure-stabilizing buffer chamber of the compressed air power unit to the air inlet of the mechanical constant flow adjustable valve through a high-pressure hose, and install a manual pressure relief button on the mechanical constant flow adjustable valve to complete the assembly of the entire system.

[0052] Operating procedures:

[0053] 1. Preparation stage: Inflate the high-pressure gas tank through the quick inflation interface until the precision pressure gauge pointer reaches 10 atm (upper limit of the green zone), check that there are no leaks at all connection points; put the inner flexible liquid storage bag filled with medicine into the outer shell and seal it, connect the infusion line, and put it into standby mode after venting.

[0054] 2. Setting stage: According to the doctor's order, rotate the flow selection knob to the target flow rate setting (e.g., 50 ml / h), and finely adjust the flow rate through the fine-tuning needle valve to ensure that it meets the treatment requirements;

[0055] 3. Start-up and Operation Phase: Open the manual switch valve, and compressed air flows out from the high-pressure storage tank. After the pressure stabilizing buffer chamber smooths out the pulsation, it enters the mechanical constant flow adjustable valve. It then passes through the pressure reducing and stabilizing module to stabilize the pressure P1, the laminar flow stabilizing module to adjust the flow rate, and the pressure compensation module to compensate for fluctuations, forming a constant gas flow rate Q_gas. The constant gas enters the driving chamber of the pneumatically driven infusion unit, uniformly squeezing the inner flexible liquid storage bag to achieve constant-speed liquid output. During operation, the precision pressure gauge pointer slowly decreases, but the feedback compensation mechanism of the constant flow valve ensures that the liquid flow rate remains basically unchanged.

[0056] 4. Monitoring and termination stage: Operators should regularly observe the pressure gauge status and infusion status. When the pressure drops to 3 atm (lower limit of the green zone), the gas source should be replaced or refilled in time. When the infusion is completed or needs to be interrupted, close the manual switch valve, press the manual pressure relief button to release the pressure of the driving air chamber, and then disconnect the infusion line.

[0057] This invention achieves high-precision constant-flow infusion in a passive environment through a purely mechanical structure, solving the application defects of existing technologies in special medical scenarios. It has significant clinical value and market prospects and can be widely applied to various power-free, power-restricted, or mobile medical scenarios.

[0058] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A dual-bottle intravenous infusion system with an adjustable mechanical constant flow valve, characterized in that, It includes a compressed air power mechanism, a mechanical constant flow adjustable valve and a pneumatically driven infusion mechanism that are connected in sequence, and achieves passive constant-speed intravenous infusion through a purely mechanical structure; The compressed air power mechanism provides the system with an independent and clean high-pressure air source, including a high-pressure air tank, a precision pressure gauge, a manual switch valve, a safety valve, a quick inflation interface, and a pressure stabilizing buffer chamber. The pressure stabilizing buffer chamber is located downstream of the manual switch valve and is used to smooth airflow pulsations. The mechanical constant flow adjustable valve is connected between the compressed air power mechanism and the pneumatically driven infusion mechanism, converting fluctuating air pressure into a constant gas flow rate. The pneumatically driven infusion mechanism is used to linearly convert a constant gas flow rate into a constant liquid flow rate output. It includes a double-layer bottle structure and a mechanical blockage alarm. The double-layer bottle structure achieves physical isolation between gas and liquid, and the mechanical blockage alarm is used for pressure alarm and pressure relief protection when the pipeline is blocked.

2. The dual-bottle intravenous infusion system with an adjustable mechanical constant flow valve according to claim 1, characterized in that, In the double-layer bottle structure of the pneumatically driven infusion mechanism, the outer layer is a rigid / semi-rigid transparent medical-grade polycarbonate shell, and the inner layer is a disposable medical PVC or TPE flexible storage bag, with a uniform gap between the flexible storage bag and the inner wall of the shell.

3. The dual-bottle intravenous infusion system with an adjustable mechanical constant flow valve according to claim 1, characterized in that, The mechanical blockage alarm is installed on the top of a transparent medical-grade polycarbonate shell and includes a safety diaphragm with a preset rupture pressure and a linked red warning bar. When the pipeline blockage causes the air chamber pressure to exceed 0.3 atm, the diaphragm ruptures, the warning bar pops out and the pressure is released.

4. A dual-bottle intravenous infusion system with an adjustable mechanical constant flow valve according to claim 2, characterized in that, The flexible storage bag is connected to a standard infusion line via a Luer connector, and the air inlet of the transparent medical-grade polycarbonate shell is connected to the outlet of the mechanical constant flow adjustable valve via a pipeline.

5. A dual-bottle intravenous infusion system with an adjustable mechanical constant flow valve according to claim 1, characterized in that, The mechanical constant flow adjustable valve adopts a three-level control architecture to convert fluctuating gas pressure into constant gas flow, including a precision pressure reduction and stabilization module, a laminar flow stabilization and flow selection module, and a feedback pressure compensation module. The precision pressure reduction and stabilization module, as the first-level control module, includes an air intake chamber and a pressure reducing diaphragm, a pressure regulating spring, and a valve core installed inside it. The pressure regulating spring is connected to the valve core. Regardless of how the pressure of the upstream air tank changes within the range of 10-3 atm, the diaphragm senses the outlet pressure and dynamically adjusts the valve core opening to stabilize the output pressure P1 at the preset value. The preload of the pressure regulating spring can be finely adjusted by an external screw. The laminar flow stabilization and flow selection module, as the second-level control module, includes a rotatable selection valve core, a flow selection knob, a dial, and a fine-tuning needle valve. The selection valve core is machined with multiple sets of parallel precision capillary channels. Rotating the knob drives the valve core to select the corresponding flow channel, and the dial marks the corresponding liquid flow rate. The feedback pressure compensation module, as the third-level control module, includes a flexible pipeline, a reference gas chamber, a compensation diaphragm, and a feedback lever. The reference gas chamber is pre-charged with a fixed pressure P_ref higher than atmospheric pressure. One side of the compensation diaphragm senses the capillary outlet pressure P2', while the other side is controlled by the force exerted by P_ref and the end force of the feedback lever. Changes in P2' will cause the diaphragm to deform, which will amplify and drive the conical valve core to move through the lever, adjust the local resistance, compensate for flow fluctuations, and ultimately output a constant gas flow rate Q_gas.

6. A dual-bottle intravenous infusion system with an adjustable mechanical constant flow valve according to claim 5, characterized in that, The fine-tuning needle valve is linked to an eccentric cam mechanism to achieve continuous and precise adjustment of ±20% within each gear position.

7. A dual-bottle intravenous infusion system with an adjustable mechanical constant flow valve according to claim 5, characterized in that, The precision capillary is made of fused silica or stainless steel and has three core flow channels: low flow rate corresponds to a liquid flow rate of 1-5 ml / h; medium flow rate corresponds to a liquid flow rate of 10-50 ml / h; and high flow rate corresponds to a liquid flow rate of 60-150 ml / h.

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