The present application discloses a micro-valve comprising: a first valve body and a second valve body, at least one of the first and second valve bodies defining a valve chamber and a valve seat, the first valve body having a liquid outlet and the second valve body having a liquid inlet; a valve plug disposed and movable within the valve chamber; and an elastic member disposed within the valve chamber and positioned closer to the liquid inlet than the valve plug. The elastic member has a liquid-inflow position and a liquid-outflow position, and in the liquid-inflow position, the elastic member enables liquid to flow from the liquid inlet through the elastic member to the liquid outlet, in the liquid-outflow position, the valve plug compresses the elastic member, such that the compressed elastic member seals the valve seat, or the compressed elastic member together with the valve plug seals the valve seat, so as to prevent liquid from flowing back from the liquid outlet to the liquid inlet through the valve seat.

TECHNICAL FIELD

The present disclosure relates to a fluid control device, and more particularly to a micro-valve structure for controlling dispensation of micro-fluid.

BACKGROUND

A micro-valve is suitable for dispensing very small amounts of liquid (e.g. in milliliter, microliter). For example, in a drug-delivery atomizer, certain amount of drug is extracted into a nozzle of the atomizer at first. The amount of drug being dispensed each time is typically 15 microliters to 2 milliliters, depending on the type of drug. For such drug-delivery atomizer, a micro-valve is desirably disposed at one end of a suction tube, for controlling the amount of fluid supplied to the drug-delivery atomizer. In clinical medicine, an intravenous injection amount per unit time for some drugs is more important than a total amount of the drugs being injected. In terms of pharmacokinetics, the shorter an interval of drug administration is, the smaller the blood concentration fluctuates. In clinical practice, constant-rate intravenous infusion is most effective. Table 1 below illustrates some commonly used drugs of intravenous general anesthesia, as well as their requirements of volume flow for the constant-rate intravenous infusion.

TABLE 1Commonly used drugs of intravenous general anesthesia, and theirrequirements of volume flow for the constant-rate intravenous infusionFlow rate ofVolume flowName ofintravenousrequirementsdruginfusion (mg/min)Form of drug liquid(ml/min)Thiopental501.0 g of each power-0.5Sodiuminjection being dilutedinto 10 mlMethohexital2-5500 mg/5 ml of injection0.02-0.05Ketamin0.5-1.5100 mg/10 ml of0.05-0.15injectionPropofol2.5-5200 mg/ml of injective0.25-0.5emulsion

If a precise syringe is not available, an intravenous drip can be used after the drug is diluted by a 5% glucose solution. The volume flow rate of intravenous drip is generally 2-4 ml/min.

If a precise syringe is manufactured using a glass needle tube and a stainless steel push rod, the requirements on the manufacturing are high, and the volume flow of injection might be significantly affected by the environment. Therefore, there is a need for a precise syringe with a micro-valve.

An existing micro-valve structure typically comprises a valve body, a valve plug, a spring and a positioner. The valve body, which is a tube-like shape, has at its one end a liquid inlet with a smaller diameter, and an inner side of the liquid inlet forms a valve seat. The valve plug is typically a valve ball, which is put into the valve seat along with the spring through the other end of the valve body. The valve ball is sealingly mated with the valve seat. The positioner is tightly mated with the other end of the valve body to position the spring and valve ball.

When the size of an exterior profile of the valve body is less than 3 mm, metallic materials e.g. stainless steel, may be used preferably. The reason for this is, for example, the difficulty of injection molding because of the small size of the parts, different situations of shrink of plastic parts for each batch of injection molding, or the difficulty in adjusting the parts from different batches. Furthermore, an existing small size metallic one-way valve is not detachable once assembled, which means that the parts cannot be detached for reuse as long as they are assembled together. Thus, the valve may not be used once any part thereof has defects. In practical production stage, each one-way valve being assembled can be put into use only after it passes a leak-checking test. An undetachable one-way valve is scrapped if it fails in the leak-checking test. In use stage, due to the corrosion and oxidation of metallic materials, materials and parts with better properties are desired for increasing service lifetime. However, liquid leakage is still inevitable for a valve after a period of time, and then the valve as a whole has to be scrapped.

In addition, because the liquid being delivered is thick, the residual liquid is easily cured into crystal within the valve body, or the elongated tube is easily blocked, the valve is disposable or has to be cleaned carefully before and after each usage. In order to make sure that no rust stain or liquid remains within the tube, a cleaning process is added, which adversely affects the service lifetime of the valve, and costs including manpower, time and resource.

Furthermore, the flow cannot be adjusted for the existing micro-valve by itself. If it is desired to adjust the flow, an additional rate control valve or other flow control valves are required mounted to the tube, or other type of one-way valve with a more complicated structure is required.

In order to solve at least one of the problems discussed above, there is a need for a new micro-valve structure.

SUMMARY

In one aspect, a micro-valve is provided. The micro-valve comprises: a first valve body and a second valve body, at least one of the first and second valve bodies defining a valve chamber and a valve seat, the first valve body having a liquid outlet and the second valve body having a liquid inlet; a valve plug disposed and movable within the valve chamber; and an elastic member disposed within the valve chamber and positioned closer to the liquid inlet than the valve plug. The elastic member has a liquid-inflow position and a liquid-outflow position, and in the liquid-inflow position, the elastic member enables liquid to flow from the liquid inlet through the elastic member to the liquid outlet, in the liquid-outflow position, the valve plug compresses the elastic member, such that the compressed elastic member seals the valve seat, or the compressed elastic member together with the valve plug seals the valve seat, so as to prevent liquid from flowing back from the liquid outlet to the liquid inlet through the valve seat.

In another aspect, a microfluidic device comprising a micro-valve is provided. The micro-valve comprises: a first valve body and a second valve body, at least one of the first and second valve bodies defining a valve chamber and a valve seat, the first valve body having a liquid outlet and the second valve body having a liquid inlet; a valve plug disposed and movable within the valve chamber; and an elastic member disposed within the valve chamber and positioned closer to the liquid inlet than the valve plug. The elastic member has a liquid-inflow position and a liquid-outflow position, and in the liquid-inflow position, the elastic member enables liquid to flow from the liquid inlet through the elastic member to the liquid outlet, in the liquid-outflow position, the valve plug compresses the elastic member, such that the compressed elastic member seals the valve seat, or the compressed elastic member together with the valve plug seals the valve seat, so as to prevent liquid from flowing back from the liquid outlet to the liquid inlet through the valve seat.

The present application has some advantages below as compared with the prior art.

1. In the prior art, a valve body of a micro-valve is typically form as an integral structure, and the design of the valve focuses more on how to position a valve plug and spring. The valve body of the present application is inventively constructed as a split structure, and the valve plug is disposed at a joint between the two valve body sections which are threadedly coupled with each other. As a result, the micro-valve can be assembled easily, and no complicated mold is required.

2. Theoretically, a throttle controls its fluid flow by adjusting the throttling section or throttling length. Since the inner part of the micro-valve of the present application can be replaced, the fluid flow of the micro-valve of the present application can be adjusted by using valve plugs having different section sizes or lengths, changing the size of its housing or spring, or other adjustment means, which is similar to the adjusting of the throttle For a situation where flow adjustment does not occurs frequently, only a portion of the parts is needed to be changed for a period of time, which reduces unnecessary storage, configuration and cost.

3. The minimum outer diameter of the entire valve can be as small as 1.5 mm. Even if the one-way valve of the present application is mounted in a tube having a small diameter, the tube section mounted with the micro-valve would not protrude from the tube. As a result, the exterior can extend smoothly, and a tube can be matched easily. The outer diameter of the valve of the present application is even smaller than a known one-way valve or check valve having a diameter of 2.5 mm available from THE LEE COMPANY.

4. The product structure can be detached easily, and thus every single part can be replaced independently. An undesirable part can be replaced in time once being found. Furthermore, the coupling between different parts of the valve can be adjusted easily, and thus the quality of the entire product can be improved. In addition, the cost of materials is reduced, and the cost for the entire product is thus reduced, which is beneficial for market competition.

5. The product structure can be detached easily, and thus visible cleaning and disinfection can be used. As a result, the use cost and process loss can be reduced.

6. The elastic member can effectively prevent backflow of liquid to the liquid pool of the atomizer.

DETAILED DESCRIPTION

The present disclosure will be more apparent in combination with drawings and embodiments.

First Embodiment

As illustrated inFIGS. 1-3, a split micro-valve is provided, which includes a first valve body section, i.e. a front valve body section1, a second valve body section, i.e. a rear valve body section4, a valve plug3, and a spring2. As shown inFIG. 3, the front valve body section1has a valve chamber10. At a first end of the front valve body section1there is a liquid outlet5, and at a second end of the front valve body section1there is an interior thread6. At a first end of the rear valve body section4there is a liquid inlet9, at a second end of the rear body section4there is an exterior thread8. The interior thread6of the front valve body section1is matably connected to the exterior thread8of the rear valve body section to form a threaded connection. In addition, the rear valve body section4defines a valve seat7at its second end.

As illustrated inFIG. 1, the spring2and the valve plug3are disposed inside the valve chamber10. A first end of the spring2is in contact with the valve plug3, and a second end of the spring2is in contact with a sidewall of the liquid outlet of the valve chamber10. In some embodiments, the valve plug is a spherical valve ball, which can be seated within the valve seat of the rear valve body section.

In some embodiments, the one-way valve can be used inside of an analgesic pump, an insulin pump, a needleless syringe, or an atomizer. It's advantageous to reduce the volume of structure, and thus to develop a portable wearable administrating device.

When manufacturing a precise syringe, flow requirements are illustrated below in Table 2.

In the embodiment, a capillary stainless steel tube is used as a valve sleeve of the body for a micro-valve, which can fully satisfy the requirement on the size of inner diameter of the micro-valve in a precise syringe application. That is, corresponding valves that match with the required inner diameter sizes can be mounted with the same syringe needle based on the requirements on different flow rates.

Second Embodiment

As illustrated inFIG. 4, a split micro-valve is provided, which includes a front valve body section1, a rear valve body section4, a valve plug3, and a spring2. The front valve body section1has a valve chamber10. At a first end of the front valve body section1there is a liquid outlet5, and at a second end of the front valve body section1there is an interior thread6. At a first end of the rear valve body section4there is a liquid inlet9, and at a second end of the rear body section4there is an exterior thread. The interior thread6of the front valve body section1is matably connected to the exterior thread8of the rear valve body section to form a threaded connection. In addition, the rear valve body section4defines a valve seat7at its second end. The spring2and the valve plug3are disposed inside the valve chamber10. In the embodiment, the valve plug is cylindrical.

Third Embodiment

As illustrated inFIG. 5, a split micro-valve is provided, which includes a front valve body1, a rear valve body4, a valve plug3, and a spring2. The front valve body section1has a valve chamber10. At a first end of the front valve body section1there is a liquid outlet5, and at a second end of the front valve body section1there is an interior thread6. At a first end of the rear valve body section4there is a liquid inlet9, and at a second end of the rear body section4there is an exterior thread. The interior thread6of the front valve body section1is matably connected to the exterior thread8of the rear valve body section to form a threaded connection. In addition, the rear valve body section4defines a valve seat7at its second end. The spring2and the valve plug3are disposed inside the valve chamber10. In the embodiment, a first end of the valve plug that contacts with the valve seat is hemispherical, and a second end of the valve plug is cylindrical.

Fourth Embodiment

As illustrated inFIGS. 6 and 7, a split micro-valve is provided, which includes a front valve body1, a rear valve body4, and a valve plug3. The front valve body section1has a valve chamber10. At a first end of the front valve body section1there is a liquid outlet5, and at a second end of the front valve body section1there is an interior thread6. At a first end of the rear valve body section4there is a liquid inlet9, and at a second end of the rear body section4there is an exterior thread. The interior thread6of the front valve body section1is matably connected to the exterior thread8of the rear valve body section to form a threaded connection. In addition, the rear valve body section4defines a valve seat7at its second end.

In the embodiment, the valve plug is spherical, and no spring is disposed. Since the volume of the valve chamber is small, the spherical valve plug is sealingly seated on the valve seat under the pressure from the outlet side when the micro-valve is in use.

Fifth Embodiment

Application of a Micro-Valve of the Present Application

The interventional injection of chemotherapeutic drugs in the treatment of cancer requires multiple points of dispersive microinjection. For an asthma patient in an acute attack, an aerosol inhalation of high concentration drug is required at a time to relieve the patient's acute symptom. The dosage of aerosol is generally 15-30 μl each time. When using a compound drug having various substances mixed in proportion, it's desired to have a precise output control over the minimum flow. In order to reach a minimum controllable output amount (volume), two key problems are needed to be solved: (1) decreasing the area of a working section; and (2) achieving a small displacement.

The micro-valve of the present application can be applied in flow control during inhalation of drug liquid from an atomizer. A minimum inner diameter of the valve chamber10can be as small as 0.4 mm, which reduces an area of a working section significantly. Moreover, under a same liquid pressure, the displacement of a valve plug can be adjusted by changing the length of the valve plug, compression amount of a spring, or stiffness of a spring, thereby satisfying the design requirement on precision.

As illustrated inFIGS. 8 and 9, an atomizer has an upper housing11and a lower housing12. A liquid pool13, a spring and a spring-positioning shell14are disposed inside the lower housing12. In the embodiment, a rear valve body section4is integrally formed with an inlet tube, which extends into the liquid pool13. A front valve body section1is threadedly coupled with the rear valve body section4. The front valve body section1and rear valve body section4form a valve body, which is inserted into a flow channel. A distal end of the flow channel adjacent to an atomizing outlet15is disposed with a positioning hole, which prevents the valve body from escaping out of the flow channel. Furthermore, the atomizer further include a first sealing16, a second sealing17, a first fastener18, and a second fastener19to sustain the stability of the valve body in a movement direction. A micro-channel is disposed between the positioning hole and the atomizing outlet, such that a high liquid pressure can be generated from an instant decrease of diameter of the channel when the liquid flows from the positioning hole having a diameter of 0.4 mm to the atomizing outlet having a diameter of 0.005 mm. The high liquid pressure pushes the valve plug3back against a liquid inlet of the rear valve body section4, thereby preventing the liquid from flowing back and forcing the liquid flow toward the atomizing outlet. The valve body is connected to the liquid pool13via a connecting member20, so as to achieve a synchronous movement.

First state: initially, the micro-valve is connected to the liquid pool13via the connecting member20, and the micro-valve is below the atomizing outlet15. A peripheral spring is pre-compressed, with its upper portion pressed against the connecting member20and its lower portion fixed by the spring-positioning shell14.

Second state: at the beginning of the liquid dispensing operation, the connecting member20is forced to move down to compress the peripheral spring further, and the micro-valve and liquid pool move down along with the connecting member. The movement of the micro-valve away from the atomizing outlet causes the valve plug to float upward, such that liquid is infused into the flow channel.

Third state: at the end of the liquid dispensing operation, the force exerted on the connecting member is released, such that the compression force on the peripheral spring rapidly decreases to move itself back to a position at the first state. The connecting member rapidly moves upward with the liquid pool and the micro-valve. The liquid in the flow channel is pushed by the micro-valve, and the valve plug is pressed by the liquid against the valve seat7of the rear valve body section4, thereby preventing liquid from flowing back. Consequently, liquid in the flow channel is dispensed out from the atomizing outlet.

Sixth Embodiment

As illustrated inFIGS. 10-12, a split micro-valve includes a valve body and a valve plug3. The valve body includes a first valve body section, i.e. a front valve body section1, and a second valve body section, i.e. a rear valve body section4. At a first end of the front valve body section1there is a liquid outlet5, and at a second end of the front valve body section1there is an exterior thread8. The rear valve body4has a valve chamber10. At a first end of the rear valve body section4there is a liquid inlet9, and at a second end of the rear valve body section4there is an interior thread6. The exterior thread8of the front valve body section1is threadedly coupled to the interior thread6of the rear valve body section4. In addition, a joint between the valve chamber of the rear valve body section and the liquid inlet9form a valve seat7. The valve plug3is disposed inside the valve chamber10of the rear valve body section, and is matable with the valve seat7at the rear valve body section.

A spring2is disposed inside the valve chamber10. A first end of the spring2is in contact with the valve plug3, and a second end of the spring2is in contact with the end of the rear valve body1having the exterior thread.

In some embodiments, as illustrated inFIGS. 12, 13, and 14respectively, the valve plug can be spherical or cylindrical. Alternatively, a first end of the valve plug that contacts with the valve seat can be hemispherical and a second end of the valve plug can be cylindrical.

Seventh Embodiment

FIGS. 15 and 16respectively show a structure diagram and an exploded view of a split micro-valve100according to another embodiment of the present application, wherein the function and structure of the components that are the same or similar as in the embodiment illustrated inFIGS. 1-7can refer to the description above. As shown inFIGS. 15 and 16, the split micro-valve100includes a front valve body101and a rear valve body104. The front valve body101has a liquid outlet105and an interior thread106, and defines a valve chamber110; the rear valve body104has an exterior thread108and a liquid inlet109. Wherein the exterior thread108extends to an end of the rear valve body104and the end of the rear valve body104defines a valve seat107. It can be understood that in some embodiments, the exterior threads108may also not extend to the end of the rear valve body104. The front valve body101and the rear valve body104are threadedly coupled together through the interior thread106and the exterior thread108. As shown inFIG. 15, when the front valve body101is threadedly coupled to the rear valve body104, a valve plug103and a spring102are received in the valve chamber110. In particular, the spring102shown inFIG. 15is disposed closer to the liquid inlet109than the valve plug103. As shown, the valve plug103is disposed having a spherical shape.

FIGS. 17a-17cshow a perspective view, a front view and a top view of the spring102ofFIG. 15. As shown inFIGS. 17a-17c, the spring102is a reduced diameter spiral spring which, in a relaxed state, has a generally tapered or truncated taper shape, such as a conical or truncated cone shape. In other embodiments, the spring102can also have a cylindrical shape, that is, a spiral spring with equal diameter. In certain embodiment, the spring102has a first end121and a second end122opposed to each other, and wherein the spring has a maximum diameter at the first end121and a minimum diameter at the second end122. That is, the diameter of the spring wire gradually decreases from the first end121to the second end122. In some embodiments, when the first end121and the second end122of the spring102are compressed, the spring wires at different positions of the spring102nest with each other and the spring102as a whole is substantially in the same plane, thereby forming a coiled-up sealing surface (seeFIG. 17c). In other embodiments, when the first end121and the second end122of the spring102are compressed, the spring wires at different positions between the first end121and the second end122may also contact each other but are not nested, such that the spring is compressed to have a truncated cone shape. It should be noted that although the spring102shown inFIGS. 17a-17chas the conical or a truncated cone shape, in practical applications, the shape of the spring can be designed and adjusted according to practical applications.

In some embodiments, the outer surface of the spring102has a sealing material such as silicone, rubber, or other sealing material with suitable resilience. When the spring102is compressed, the sealing material can effectively seal the gap that may exist between the two mutually contacting spring wires, so that the compressed spring102has a good sealing effect.

In some embodiments, the second end122of the spring102can be fixed to the rear valve body, such as welded or bonded to the rear valve body. In other embodiments, the spring102may not be fixed to the rear valve body.

Return toFIGS. 15 and 16, the spring102is in the liquid-inflow position, when the atomizer pumps the liquid from the liquid pool into the tube at the Second State (the start of operation). At this time, the liquid flows into the micro-valve100from the liquid pool through the liquid inlet109in the direction indicated by the arrow inFIGS. 15 and 16, and flows out of the liquid outlet105into the tube of the atomizer. At this time, the valve plug103does not compress the spring102toward the liquid inlet109, so the valve seat107is open.

FIG. 18shows the structure of the micro-valve100when the atomizer is in the Third State (the end of operation). As shown inFIG. 18, when the liquid in the tube is pushed by the micro-valve100and dispensed from the atomizer, the increased pressure in the tube downstream of the liquid outlet105causes the valve plug103to move toward the liquid inlet109, thereby compressing the spring102together with the valve seat107. At this time, the spring is in the liquid-outflow position. As mentioned above, the spring102can be compressed into a coiled-up sealing surface that can seal the valve seat107alone or in conjunction with the valve plug, so as to prevent backflow of liquid via the valve seat107.

The embodiment of the atomizer shown inFIGS. 15 to 16includes a spring102adjacent the liquid inlet109without including a spring adjacent the liquid outlet105. In other embodiments, the atomizer can include springs adjacent both the inlet and outlet, i.e., the spring of the embodiment ofFIG. 1can be further included in the embodiment illustrated inFIGS. 15 and 16. The length and elasticity of the two springs can be designed so that the spring close to the liquid outlet prevents the valve plug from blocking the liquid outlet when pumping liquid (the Second State), and the spring close the liquid inlet is compressed to seal the valve seat107when dispensing liquid (the Third State).

FIGS. 19aand 19billustrate another embodiment of a split micro-valve100respectively. In the embodiment ofFIG. 19a, the valve plug103is configured to have a substantially cylindrical shape; and in the embodiment ofFIG. 19b, the valve plug103is configured to have a semi-cylindrical and hemispherical shape. A person skilled in the art will appreciate that the valve plug103can be designed to have different shapes as needed.

Eighth Embodiment

FIGS. 20 and 21illustrate perspective views of a split type micro-valve200according to another embodiment of the present application.FIGS. 22a-22cillustrate a structure of the spring of the split micro-valve200. As shown inFIGS. 22a-22c, the spring202of the split micro-valve200is similar to the spring102, but is further disposed with a blocking member223at its second end222. In an embodiment, the blocking member223can have a spherical shape; a person skilled in the art will appreciated that the blocking member223can be designed to have other shapes as needed. When the spring202is compressed in the direction toward the liquid inlet209via the valve body203together with the valve seat207, the blocking member223can abut against the valve body203. Further, when the spring202is fully compressed, the blocking member223substantially blocks a through hole at the center of the fully compressed spring202. It will be appreciated that the split micro-valve200can further prevent backflow of liquid to the liquid pool as compared to the split micro-valve100.

FIGS. 23a-23cillustrate three embodiments of the split micro-valve200. It will be appreciated that the valve plug203can be designed to be spherical (FIG. 23a), cylindrical (FIG. 23b), and a semi-cylindrical and hemispherical shape as needed (FIG. 23c). A person skilled in the art will appreciate that the valve plug203can be designed to have different shapes as needed.

Ninth Embodiment

FIGS. 24 and 25illustrate perspective views of a split micro-valve300according to another embodiment of the present application, wherein like components are indicated by like reference numbers inFIGS. 15-19plus200.FIGS. 26a-26cillustrate a structure of the spring of the split micro-valve300. As shown inFIGS. 26a-26c, the split micro-valve300includes a leaf spring302. The leaf spring302includes an annular portion321and a circular portion323that is connected to the annular portion321by a hinge322. It will be appreciated that the circular portion323can be switched between an open position and a closed position by the hinge322. When in the closed position, the annular portion321and the circular portion323form a complete sealing surface. In an embodiment, the circular portion323further includes a recess324that faces the liquid inlet309, and the recess324is capable of engaging the valve plug303.

Return toFIG. 24, when the atomizer pumps the liquid in the liquid pool into the tube at the aforementioned Second State (the start of operation), the liquid flows from the liquid pool into the micro-valve300through the liquid inlet309in the direction indicated by the arrow inFIG. 24, and flows out of the liquid outlet305into the tube. The circular portion323is now in the open position to allow the liquid to flow through.

As shown inFIG. 25, when the liquid in the tube is pushed by the micro-valve300to dispense out of the atomizer, the increased pressure in the tube causes the valve plug303to move toward the liquid inlet309, thereby pressing, together with the valve seat307, the circular portion323to the closed position. At this time, the circular portion323which is pressed to the closed position forms a complete sealing surface along with the annular portion321, so that the backflow of the liquid back into the liquid pool can be well prevented.

FIGS. 27a-27cillustrate three embodiments of the split micro-valve300. It will be appreciated that the valve plug303can be designed to have shapes like spherical (FIG. 27a), cylindrical (FIG. 27b), and cylindrical at one end and hemispherical at the other end (FIG. 27c). A person skilled in the art will appreciate that the valve plug303can be designed to have different shapes as needed.

Tenth Embodiment

FIGS. 28 and 29illustrate perspective views of a split micro-valve400in accordance with another embodiment of the present application, wherein like components are indicated by like reference numbers inFIGS. 15-19plus300. As compared to the split micro-valve300, the split micro-valve400further includes a limiting member422located within the valve chamber410. When the front valve body401is coupled with the rear valve body404, the limiting member422can abut the leaf spring402against the valve seat407, thereby preventing the leaf spring402from getting off the valve seat407in the Second State (the start of operation) of the atomizer. In the embodiment ofFIGS. 28-29, the limiting member422is a limiting spring having a length substantially equal to or longer than the length of the valve chamber410such that when the front valve body401is coupled with the rear valve body404, the limiting spring can abut the leaf spring402against the valve seat407. It will be appreciated that since the limiting spring has a generally hollow cylindrical shape, the movement of the valve plug403in the valve chamber410is substantially unaffected by the limiting member422.

FIGS. 30 and 31illustrate perspective views of another embodiment of the split micro-valve400. As illustrated inFIGS. 30 and 31, different from the limiting spring in the embodiment ofFIGS. 28 and 29, the limiting member422of the split micro-valve400can also be a limiting sleeve, whose length is substantially equal to the length of the valve chamber410such that the limiting sleeve can abut the leaf spring402against the valve seat407when the front valve body401is coupled with the rear valve body404. A person skilled in the art will appreciate that other types of limiting member can be used to secure the leaf spring402to the valve seat407. In addition, the leaf spring402can also be secured to the valve seat407by other means, such as by welding or bonding.

If the leaf spring402is not fixed to the valve seat407, the leaf spring402may get off the valve seat407in the operational start state of the atomizer (the Second State). In this case, when the atomizer is dispensing (the Third State), it may take a long time for the leaf spring402to return from the position where it is disengaged from valve seat407to the position against the valve seat407(where a sealing surface is formed at the valve seat407), resulting in a small amount of liquid backflow. Therefore, the embodiment enables the leaf spring402to always be in a position abutting against the valve seat407, which enables the leaf spring402to form a good sealing surface quickly and in time when the atomizer is dispensing, thereby avoiding or reducing liquid backflow as much as possible.

Eleventh Embodiment

FIGS. 32-34illustrate a split micro-valve500according to yet another embodiment of the present utility model. Unlike the split micro-valves100,200,300, in the split micro-valve500, the front valve body501has an exterior thread and a valve seat at the end of the exterior thread, and the rear valve body504has an interior thread and defines a valve chamber410. The valve plug and spring (or leaf spring) of the split micro-valve500are similar to the valve plug and spring (or leaf spring) of the split micro-valves100,200,300, and will not be described herein.