Patent Application
20090297371
This application claims benefit from the priority of Taiwan Patent Application No. 097119884 filed on May 29, 2008, the disclosure of which is incorporated by reference herein in their entirety.
Not applicable.
1. Field of the Invention
The present invention provides a fluid delivery device. In particular, the present invention provides a portable and non-directional fluid delivery device suitable for delivering a small amount of fluid, which can be applied in portable miniature products. For example, it can be used in a fuel cell system to provide material(s) required for cell operation.
2. Descriptions of the Related Art
Traditionally, mechanical pumps are used for fluid delivery. A pressure source is generated by mechanical compression, so that a fluid is transported from one high-pressure end to another low-pressure end. Although this kind of mechanical pump usually has greater delivery ability, it has a larger system volume and consumes more energy.
However, current products, such as 3C products and fuel cells, are all becoming miniaturized, and the delivery for only a small amount of fluid is often involved. Thus, traditional mechanical pumps with greater delivery ability are not appropriate. In addition, their large volumes are not suitable for high-tech products, in which miniaturization is in high demand. Furthermore, with the progress of technology and the need for environmental protection, every invention/design has tried to lower the amount of energy consumed. The traditional mechanical pumps in operation require the use of constant electric power for delivery, and thus, clearly can't meet the expectation. Hence, it is important to provide a miniaturized fluid delivery device that not only delivers a small amount of fluid, but also consumes a lower amount of energy.
In the prior art, the principle of capillary siphoning has been applied to the delivery technique for small amounts of fluid, in which the gravity of a fluid to be delivered is overcome by the capillary siphoning. Nevertheless, capillary siphoning is influenced by not only the kind of fluids to be delivered and surface tension, but also temperature, pressure, and other factors. For instance, when the pressure at the delivered end is higher, it is difficult to solely use capillary siphoning to deliver the fluids. Moreover, once an employed capillary is installed, the flow amount delivered within a unit time cannot be adjusted, and thus, making it inconvenient in application.
The present invention provides a portable fluid delivery device for delivering a small amount of fluid with a small operation volume, ability to deliver liquid stably, flexibility for changing the flow amount depending on the requirements, and low-energy consumption, etc.
One objective of this invention is to provide a fluid delivery device, comprising an internal container with a first opening and a first space for containing a fluid to be delivered, wherein the internal container is made of a flexible material; an external container substantially surrounding the internal container to form a substantially sealed second space between the internal container and the external container, wherein the external container has a second opening corresponding to the first opening and is made of a rigid material; an assistant liquid in the second space, wherein the boiling point of the assistant liquid is not higher than that of the fluid to be delivered; and a first delivery pipe, including a first segment within the first space and a second segment stretched out from the first opening, wherein the first segment has a hole for communicating with the first space and the second segment is tightly bound with the first opening and the second opening and has a fluid outlet. When the device is in a state of use, the first space contains a fluid to be delivered, the assistant liquid is heated and vaporized by a heat resource to raise the pressure in the second space to cause a pressure difference between the first space and the second space; and the internal container is compressed by the pressure difference to drive the fluid in the first space out from the delivery device via the first delivery pipe and the fluid outlet.
Another objective of this invention is to provide a fluid delivery device, comprising: an internal container with a first opening and a first space for a fluid to be delivered, wherein the internal container is made of a flexible material; an external container substantially surrounding the internal container to form a substantially sealed second space between the internal container and the external container, wherein the external container has a second opening and an inlet for filling an assistant liquid and is made of a rigid material, and the second opening corresponds to the first opening; a second switching structure for controlling the inlet for filling an assistant liquid, installed to correspond to the inlet for filling an assistant liquid; and a first delivery pipe, including a first segment within the first space and a second segment stretched out from the first opening, wherein the first segment has a hole for communicating with the first space and the second segment is tightly bound with the first opening and the second opening. Besides, the second segment has a fluid outlet, wherein, when the fluid delivery device is in a state of use, the first space contains a fluid to be delivered and the second space contains an assistant liquid, wherein the boiling point of the assistant liquid is not higher than that of the fluid to be delivered. The assistant liquid is heated and vaporized by a heat resource to raise the pressure in the second space to cause a pressure difference between the first space and the second space. The internal container is compressed by the pressure difference to drive the fluid out from the delivery device via the first delivery pipe and the fluid outlet.
The subject invention is described in detail with preferred embodiments in the following paragraphs accompanying the appended drawings for people skilled in this field to well appreciate the aforesaid purposes, the technical features, and the advantages of the claimed invention.
The vocabulary used herein is for describing embodiments only, not for limiting the scope of the present invention. For example, unless specifically defined, the word “a(n)” covers singular and plural forms. For instance, “an internal container” may represent one internal container or two or more internal containers, and “a hole” may represent one hole or two or more holes.
The embodiments of the present invention will be specifically described with the appended drawings as following. However, this invention can be carried out in many different forms, and thus, the scope of the present invention should not be limited to the embodiments described in this specification. In addition, for clarity, the size of each element and each area may be exaggerated in the figures and is not depicted as their actual scale.
Firstly, in reference to
As shown in
When the fluid delivery device 1 is in a state of use, the fluid to be delivered is placed in the first space 14. The assistant liquid in the second space 15 is heated and vaporized to raise the pressure in the second space 15 to cause a pressure difference between the interior and the exterior of the internal container 11, so that the internal container 11 is compressed to drive the fluid out via the first delivery pipe 13.
The internal container 11 should be made of a flexible material, so that the distortion of the internal container 11 can be generated when it is subjected to an external pressure. In addition, to prevent the internal container 11 from damaging by the properties of the fluid to be delivered or the assistant liquid itself (e.g. corrosiveness), or by the delivery process driven by heating/compression (i.e. to consider the factors such as the kinds of fluids to be delivered and assistant liquids, the operation temperature of the device, and the like), the material of the internal container 11 preferably has good pressure resistance, heat resistance, corrosion resistance, and the like, depending on the requirements. Materials suitable for the material of the internal container 11 can be such as, but not limited to, polyethylene, polyvinyl chloride (PVC), neoprene, silicone rubber, and the like. The preferred materials are neoprene and silicone rubber. Additional processing can be carried out on the surface of the internal container 11 that comes into contact with the fluid to be delivered or the assistant liquid to provide the desired fluid resistance.
The fluid delivery device 1 can be used for delivering any fluid that is in the liquid state at room temperature. Non -limiting examples for the fluids are alcohols, alkanes, water, and a combination thereof. Preferably, the fluids are selected from a group consisting of water, methanol, ethanol, gasoline, diesel fuel, and combinations thereof. In an embodiment of the present invention, the fluid delivery device 1 is used for delivering methanol or a methanol aqueous solution for the operation of a fuel cell.
The selection of assistant liquids depends on the kind of fluids to be delivered, and the premise is that the boiling point of the assistant liquid should not be higher than that of the fluid to be delivered. Thus, the assistant liquid can be evaporated during the heating process to generate a pressure driving the fluid to flow out from the internal container 11. For instance, if the fluid to be delivered is water, methanol, ethanol, or a combination thereof, the assistant liquid can be selected from a group consisting of water, a C5-C6 hydrocarbon (which can be branched chain, straight chain, cyclic shape, saturation, or unsaturation), a C2-C3 carbonyl compound, a C1-C2 alcohol, and combinations thereof. For example, the assistant liquid can be selected from a group consisting of pentane, cyclopentane, hexane, cyclohexane, acetone, propanal, and combinations thereof. If the fluid is gasoline or diesel fuel, the assistant liquid can be selected from a group consisting of: gasoline, diesel fuel, methanol, isopropanol, dichloromethane, and combinations thereof.
To generate a pressure compressing the internal container 11 when the assistant liquid is heated and evaporated, the external container 12 is made of a substantially rigid material. Any suitable rigid material can be used to provide the external container 12, and a material with pressure resistance, heat resistance, assistant liquid resistance, and the like is preferred. In addition, depending on the requirements, the surface of the external container 12 coming into contact with the assistant liquid can be processed to provide the appropriate assistant liquid resistance. Non-limiting examples for a rigid material used to manufacture the external container 12 can be selected from plastic, metal, and a combination thereof, such as polypropylene, polyethylene, stainless steel, aluminum, or a combination thereof.
Further referring to
The second segment of the first delivery pipe 13 refers to the portion of the first delivery pipe 13 stretched out from the first opening, while the second segment has a fluid outlet 133 and is tightly bound with the first opening and the second opening. Generally speaking, there is no a particular limit on the way of binding, as long as there is no liquid or gas leakage. For instance, a chemical approach, a physical approach, or a combination thereof can be used. In terms of chemical approaches, a suitable adhesive can be used on the fluid delivery device 1 to stick the first/second opening to a corresponding position on the outside of the first delivery pipe 13 to prevent gas and/or liquid from leaking out of the fluid delivery device 1. There is no a particular limit on the employed adhesive, usually, for example, unsaturated polyester resin, epoxy resin, furan-formaldehyde resin, phenol resin, or the like can be used. Also, when the first delivery pipe 13, and the internal container 11 and/or the external container 12 are made of a thermoplastic material, a thermo-pressing method can be applied to make the first/second opening tightly bind to the first delivery pipe 13.
Physical approaches also can be used to make the first and the second openings tightly bind to the first delivery pipe 13. For example, referring to
As described hereinbefore, the preferred embodiment of the fluid delivery device according to the present invention is installed with a plurality of holes 131 which are not all on the same line parallel to the axial line of the first delivery pipe 13. Because the first delivery pipe 13 has a plurality of holes 131 installed in the aforesaid way, the fluid that is delivered can enter the first delivery pipe 13 through the holes 131 from different directions when the internal container 11 is subjected to the compression, and thus does not limit the delivery direction and prevent blockage. Herein, the first delivery pipe 13 should be made of a rigid material to prevent it from distortion during the compression process and hindering the fluid delivery. Hence, the material of the first delivery pipe 13 should be selected from materials with the properties of pressure resistance, heat resistance, and corrosiveness resistance. For instance, it can be selected from a group consisting of stainless steel, aluminum, polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), and combinations thereof.
In an embodiment of the present invention, the first space 14 is filled with a fluid to be delivered; that is, there is no gas in the first space 14. Thus, if there is any movement during operation, the fluid to be delivered still can be introduced into the first delivery pipe 13 through the holes 131 in any placing direction, to achieve the desired fluid delivery.
To further increase the convenience of utilization and the environmental protection, the fluid delivery device according to the present invention is preferably designed to be used repeatedly. Namely, the present invention is designed to be optionally filled with one or more fluids to be delivered in the internal container 11. The fluid to be delivered can be filled through the outlet of the first delivery pipe, or be filled through an additional inlet (which will be described in the subsequent embodiment). When a fluid to be filled is different from the originally filled fluid, a cleaning process can optionally be carried out before the different fluid is filled. For example, a cleaning solution is introduced into the internal container 11 and then is discharged by the fluid delivery method described hereinbefore. Finally, air is injected and purged into the internal container to dry it. People with ordinary skill in the art may proceed with a suitable cleaning process and choose an appropriate cleaning solution based on their knowledge, and the details are not described herein.
When the fluid delivery device according to the present invention is in a state of use, an assistant liquid is evaporated to generate a vapor pressure by heating the assistant liquid in the second space 15 to increase the pressure in the second space 15. The internal container 11 is subjected to compression due to the pressure difference between the first space 14 and the second space 15 to drive the fluid to be delivered in the first space 14 to enter the first delivery pipe 13 from the holes 131 and finally be discharged from a fluid outlet 133. The generated vapor pressure in the second space 15 can be controlled by adjusting the intensity of a heat source to further modulate the flow amount of the fluid delivery. Any suitable heating method can be adopted depending on the requirements. For example, the heat source that can be applied to the device according to the present invention can be selected from a group consisting of a high-temperature liquid, a high-temperature gas, chemical reaction heat, an electric heating wire, a heating band, a hot air pipe, a hot liquid pipe, an electric fire, and combinations thereof.
For instance, the fluid delivery device according to the present invention can be used by adopting the approach of heating an assistant liquid directly or indirectly. As shown in
To maintain the utilization efficiency of the fluid delivery device according to the present invention, the fluid delivery device preferably comprises a controlling element with a switch function to segregate the first delivery pipe 13 from outside as the fluid delivery device is not in a state of use, thereby to prevent outside air from entering the first space 14. As shown in
Two or more internal containers also can be used in the fluid delivery device according to the present invention to deliver two or more kinds of fluids to be delivered at the same time to increase the applicability of the device.
Another embodiment of the present invention is a fluid delivery device 3 as shown in
In the aforesaid descriptions, depending on the adopted material, the third opening and the fourth opening can be stuck together by an appropriate chemical or/and physical approach to maintain the substantially sealed state of the second space 33 and prevent the liquid in the internal container 31 from leakage. In addition, the position of the inlet for filling a fluid to be delivered is preferably on the wall of the external container 32 corresponding to the first opening. M ore preferably, as shown in
To increase the applicability of the present invention, an inlet for filling an assistant liquid can be additionally installed on the external container of a fluid delivery device optionally to fill the assistant liquid to replace the assistant fluids expediently according to the properties of the fluid to be delivered to enhance the utilization of the fluid delivery device. In this embodiment, the fluid delivery device further comprises a switching structure installed to correspond to the inlet for filling the assistant liquid. As shown in
The present invention will be further illustrated with specific examples as follows to manifest the performance of the present invention.
A fluid delivery device as shown in
A heat source was provided by means of a water bath, and a needle valve was used as the controlling element of the fluid delivery device. A water manometer was placed in a second space to measure the pressure variation in the second space. First, the fluid delivery device was placed into a water bath at 30° C. After the thermal equilibrium was reached, the needle valve was turned on and fixed to a certain opening. Meanwhile, the relationship of the pressure difference versus the flow amount was measured and recorded, wherein the fluid delivery device is placed in the upstanding position and the recording time started right after the needle valve is turned on. The test result is recorded in Table 1.
As can be seen from Table 1, after the pressure in the second space 15 became stable, the flow amount was almost unchanged. Therefore, it is shown that the fluid delivery device according to the present invention can stably provide the function of the fluid delivery without impulse.
Through the same device and heating method as Example 1, the stability of the fluid delivery device was tested, except that the temperature of the water bath was adjusted to 33° C. During the testing process, the fluid delivery device was turned 90° at the 9th minute (i.e. in laid down position), and was turned 90° again at the 12th minute (i.e. being turned 180° from its original position, in upside-down position), and then was turned back to the original upstanding position at the 17th minute. During the process, the relationship of the pressure difference versus the flow amount was measured and recorded. The test result is recorded in Table 2.
As shown in Table 2, during the process of turning the fluid delivery device, the flow amount didn't change remarkably. That is, when the fluid delivery device is in a state of use, the placing direction doesn't influence the whole stability or cause obvious variation in the flow amount. Particularly, after the placing direction was altered, the flow amount stabilized immediately. Therefore, it is shown that the fluid delivery device according to the present invention has the non-directional property indeed.
Through the same device and heating method as Example 1, the relationship between the flow amount and the pressure was tested, except that the temperature of the water bath was increased from 30° C. to 40° C. during the testing process to change the pressure in the second space 15. The relationship between the pressure difference and the flow amount was recorded. The test result is recorded in Table 3, and a graph of the pressure difference versus the flow rate at the outlet (i.e.
As can be seen in Table 3 and
Through the same device and heating method as Example 1, the relationship between the valve opening and the flow amount was tested, except that during the testing process, after the temperature of the device became stable, the needle valve opening (the flow amount at outlet) was set to 1 ml/min, and it was set to 0.4 ml/min during the 11th to the 18th minutes of the testing time, and then it was set to 3.4 ml/min during the 19th to the 30th minutes. The test result is recorded in Table 4.
As can be seen in Table 4, when the valve opening was altered, the flow amount delivered within a unit time can be promptly and stably changed.
From the above examples, it is found that the fluid delivery device according to the present invention has the stable ability of the fluid delivery and meets the demand for changing the delivery flow amount efficiently by altering the intensity of the heat resource or adjusting the switching degree of the control element. In addition, the fluid delivery device according to the present invention is further able to overcome the limit of directivity, and the fluid delivery can be performed in any direction, and thus, it is very suitable for application in portable devices. Moreover, because the fluid delivery device according to the present invention may have a small size, the waste heat, for example, discharged by peripheral devices of an installed system, can be utilized as a heat source, using energy efficiently.
The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof. Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended.
| Number | Date | Country | Kind |
|---|---|---|---|
| 097119884 | May 2008 | TW | national |
