US20100086416A1

US20100086416A1 - Thermo-pneumatic peristaltic pump

Info

Publication number: US20100086416A1
Application number: US12/325,060
Authority: US
Inventors: Yao-Joe Yang; Bonnie Tingting Chia; Hsin-Hung Liao; Ming-Yuan Cheng
Original assignee: National Taiwan University NTU
Current assignee: National Taiwan University NTU
Priority date: 2008-10-02
Filing date: 2008-11-28
Publication date: 2010-04-08
Also published as: TW201014977A

Abstract

A thermo-pneumatic peristaltic pump. A heating base board includes at least one heater. A membrane disposition board is disposed on the heating base board and includes at least one membrane chamber. The membrane chamber includes a first chamber body and a second chamber body. The first chamber body connects to the second chamber body and covers the heater. A fluidic receiving board is disposed on the membrane disposition board and includes at least one fluidic chamber, a fluidic inlet, and a fluidic outlet. The fluidic chamber is connected between the fluidic inlet and the fluidic outlet and is disposed on the second chamber body of the membrane chamber.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This Application claims priority of Taiwan Patent Application No. 097137881, filed on Oct. 2, 2008, the entirety of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates to a thermo-pneumatic peristaltic pump, and more particularly to a thermo-pneumatic peristaltic pump that provides a reduced heating effect on a fluid transported thereby.
2. Description of the Related Art
Generally, a biomedical micro electro-mechanical system (Bio-MEMS) is used for micro analytical instruments and accomplishes multiple inspections and analyses on a single chip, such as a lab-on-a-chip (LOC) or Bio-chip. Micro elements manufactured by a micro electro-mechanical processing technique may provide advantages of reduced manufacturing costs of detection instruments, reduced consumption of inspection reagent, reduced man-made operational errors, increased inspection and analysis speed, and enhanced sensitivity and accuracy, facilitating thorough research for related biological information.
Fluidic control on the LOC or Bio-chip is often accomplished by a peristaltic pump. The peristaltic pump utilizes reciprocal motion of membranes to alter the volume of fluidic chambers, forcing a fluid in the fluidic chambers to flow in a specific direction. Moreover, the peristaltic pump may be categorized into electrostatic, shape-memory-alloy, thermo-pneumatic, piezoelectric, electromagnetic, and pneumatic types.
Regarding a pneumatic peristaltic pump, a huge externally connected aeration device is required. The aeration device sends high-pressure gas into the pneumatic peristaltic pump to drive membranes therein to reciprocate, enabling flowing of a fluid. Although powerfully pushing the fluid forward, the pneumatic peristaltic pump is a huge and complex structure, thereby causing inconvenience of employment. To solve the aforementioned disadvantages, a thermo-pneumatic peristaltic pump can replace the pneumatic peristaltic pump to play a critical role in driving the fluid to flow in a micro fluidic system.
Referring to FIG. 1A and FIG. 1B, a conventional thermo-pneumatic peristaltic pump 1 comprises a heating base board 10, a membrane disposition board 20, and a fluidic receiving board 30.
The heating base board 10 comprises a plurality of heaters 11, a plurality of first electrodes 12 a, and a plurality of second electrodes 12 b. Each heater 11 is connected between each first electrode 12 a and each second electrode 12 b. Additionally, the first electrodes 12 a and second electrodes 12 b are electrically connected to a controller (not shown).
The membrane disposition board 20 is disposed on the heating base board 10 and comprises a plurality of membrane chambers 21. Specifically, the membrane chambers 21 correspond to and cover the heaters 11, respectively.
The fluidic receiving board 30 is disposed on the membrane disposition board 20 and comprises a plurality of fluidic chambers 31, a fluidic inlet 32, and a fluidic outlet 33. The fluidic chambers 31 sequentially connect to each other and are connected between the fluidic inlet 32 and the fluidic outlet 33. Additionally, the fluidic chambers 31 are disposed on the membrane chambers 21 of the membrane disposition board 20, respectively.
When the thermo-pneumatic peristaltic pump 1 drives a fluid to flow, the controller performs sequential control for pushing the fluid. Namely, the controller sequentially electrifies the heaters 11 via the first electrodes 12 a and second electrodes 12 b, enabling heating operation of the heaters 11. Specifically, as shown in FIGS. 2A, 2B, and 2C, the controller electrifies only two heaters 11 every time, heating air in closed spaces between the two heaters 11 and two corresponding membrane chambers 21. Here, the air in the closed spaces between the two heaters 11 and the two corresponding membrane chambers 21 is heated to expand, increasing the volume of the two corresponding membrane chambers 21, and further forcing the two corresponding membrane chambers 21 to bulge upward. In another aspect, when the controller stops electrifying a certain heater 11, the air in the closed space between the heater 11 and a corresponding membrane chamber 21 cools down, such that the volume of the corresponding membrane chamber 21 returns to an original size and the corresponding membrane chamber 21 does not bulge upward any more. Accordingly, by repeatedly and sequentially controlling the heating operation of the heaters 11 using the controller, the fluid can flow into the fluidic chambers 31 via the fluidic inlet 32 and flow out of the fluidic chambers 31 via the fluidic outlet 33.
Nevertheless, in practical application, the thermo-pneumatic peristaltic pump 1 has many drawbacks. Because the fluidic chambers 31 are disposed right on the heaters 11, the fluid flowing through the fluidic chambers 31 is directly heated by the heaters 11 and thus provides an increased temperature, adversely affecting the structure or character of the fluid. Specifically, when the temperature of the fluid increases, the structure of the fluid may be damaged, bubbles may occur in the fluid, or the fluid may be vaporized. Thus, subsequent application, such as inspection and analysis, of the fluid output from the thermo-pneumatic peristaltic pump 1 is adversely affected. Moreover, as the membrane chambers 21 provide a limited volume, a fluidic pushing force generated by the thermo-pneumatic peristaltic pump 1 is limited.

BRIEF SUMMARY OF THE INVENTION

A detailed description is given in the following embodiments with reference to the accompanying drawings.
An exemplary embodiment of the invention provides a thermo-pneumatic peristaltic pump comprising a heating base board, a membrane disposition board, and a fluidic receiving board. The heating base board comprises at least one heater. The membrane disposition board is disposed on the heating base board and comprises at least one membrane chamber. The membrane chamber comprises a first chamber body and a second chamber body. The first chamber body connects to the second chamber body and covers the heater. The fluidic receiving board is disposed on the membrane disposition board and comprises at least one fluidic chamber, a fluidic inlet, and a fluidic outlet. The fluidic chamber is connected between the fluidic inlet and the fluidic outlet and is disposed on the second chamber body of the membrane chamber.
The membrane chamber further comprises a connecting chamber body connecting the first chamber body to the second chamber body.
The heating base board further comprises at least one first electrode and at least one second electrode. The heater is connected between the first and second electrodes.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1A is a perspective assembly view of a conventional thermo-pneumatic peristaltic pump;

FIG. 1B is an exploded perspective view of the conventional thermo-pneumatic peristaltic pump of FIG. 1A;

FIG. 2A is a schematic cross section of the conventional thermo-pneumatic peristaltic pump in an operational mode;

FIG. 2B is a schematic cross section of the conventional thermo-pneumatic peristaltic pump in another operational mode;

FIG. 2C is a schematic cross section of the conventional thermo-pneumatic peristaltic pump in yet another operational mode;

FIG. 3A is a perspective assembly view of a thermo-pneumatic peristaltic pump of the invention; and

FIG. 3B is an exploded perspective view of the thermo-pneumatic peristaltic pump of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.
Referring to FIG. 3A and FIG. 3B, a thermo-pneumatic peristaltic pump 100 comprises a heating base board 110, a membrane disposition board 120, and a fluidic receiving board 130.
The heating base board 110 comprises a plurality of heaters 111, a plurality of first electrodes 112 a, and a second electrode 112 b. Each heater 111 is connected between each first electrode 112 a and the second electrode 112 b. Additionally, the first electrodes 112 a and second electrode 112 b are electrically connected to a controller (not shown).
The membrane disposition board 120 is disposed on the heating base board 110 and comprises a plurality of membrane chambers 121. Each membrane chamber 121 comprises a first chamber body 121 a, a second chamber body 121 b, and a connecting chamber body 121 c. In this embodiment, each connecting chamber body 121 c connects each first chamber body 121 a to each second chamber body 121 b, and each first chamber body 121 a covers each heater 111. Additionally, the membrane disposition board 120 may be composed of Polydimethylsiloxane (PDMS).
The fluidic receiving board 130 is disposed on the membrane disposition board 120 and comprises a plurality of fluidic chambers 131, a fluidic inlet 132 a, and a fluidic outlet 132 b. The fluidic chambers 131 are sequentially connected to each other and are connected between the fluidic inlet 132 a and the fluidic outlet 132 b. Specifically, each fluidic chamber 131 is disposed on each second chamber body 121 b of each membrane chamber 121 and diverges from each first chamber body 121 a covering each heater 111.
When the thermo-pneumatic peristaltic pump 100 drives a fluid to flow, the controller performs sequential control for pushing the fluid. Namely, the controller sequentially electrifies the heaters 111 via the first electrodes 112 a and second electrode 112 b, enabling heating operation of the heaters 111. Specifically, the controller electrifies only two heaters 111 every time, heating air in closed spaces between the two heaters 111 and two corresponding membrane chambers 121. Here, the air in the closed spaces between the two heaters 111 and the two corresponding membrane chambers 121 is heated to expand, increasing the volume of the two corresponding membrane chambers 121, and further forcing the two corresponding membrane chambers 121 to bulge upward. In another aspect, when the controller stops electrifying a certain heater 111, the air in the closed space between the heater 111 and a corresponding membrane chamber 121 cools down, such that the volume of the corresponding membrane chamber 121 returns to an original size and the corresponding membrane chamber 121 does not bulge upward any more. Accordingly, by repeatedly and sequentially controlling the heating operation of the heaters 111 using the controller, the fluid can flow into the fluidic chambers 131 via the fluidic inlet 132 a and flow out of the fluidic chambers 131 via the fluidic outlet 132 b.
Moreover, the raised height of the central portion of each conventional membrane chamber 21, i.e. the difference between the height of the central portion of each membrane chamber 21 after expansion and that before expansion, can be expressed by the following equation:
$s = \frac{3 V_{0} λ Δ T}{π R^{2}}$
wherein, s denotes the raised height of the central portion of the membrane chamber 21, V₀denotes the volume of the closed space between the heater 11 and the corresponding membrane chamber 21 before heating, γ denotes the coefficient of expansion of air, ΔT denotes the temperature difference in the membrane chamber 21, and R denotes the radius of the fluidic chamber 31.
According to the equation above, when the values of γ and R are fixed, the value of s is in proportion to the values of V₀and ΔT. Namely, the value of s increases when the value of V₀increases and the value of ΔT is fixed, or the required value of ΔT for providing the same value of s reduces when the value of V₀increases.
Accordingly, the thermo-pneumatic peristaltic pump 100 provides many advantages as follows. Because the fluidic chambers 131 are not disposed right on the heaters 111, the fluid flowing through the fluidic chambers 131 is not heated directly by the heaters 111 and the temperature of the fluid is not increased as obviously as the case heating directly. Thus, the structure or character of the fluid can be stably maintained, benefiting subsequent application, such as inspection and analysis, of the fluid output from the thermo-pneumatic peristaltic pump 100. Moreover, as each membrane chamber 121 comprises a first chamber body 121 a, a second chamber body 121 b, and a connecting chamber body 121 c, the overall volume of each membrane chamber 121 is immensely increased, i.e. the value of V₀is immensely increased. Thus, after heated, each membrane chamber 121 provides an enhanced expansion effect, generating a greater fluidic pushing force. Additionally, as the overall volume of each membrane chamber 121 is immensely increased, the temperature difference therein may be selectively reduced (i.e. the value of ΔT may be selectively reduced), thereby reducing consumption of electric power.
While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.

Claims

1. A thermo-pneumatic peristaltic pump, comprising:

a heating base board comprising at least one heater;

a membrane disposition board disposed on the heating base board and comprising at least one membrane chamber, wherein the membrane chamber comprises a first chamber body and a second chamber body, and the first chamber body connects to the second chamber body and covers the heater; and

a fluidic receiving board disposed on the membrane disposition board and comprising at least one fluidic chamber, a fluidic inlet, and a fluidic outlet, wherein the fluidic chamber is connected between the fluidic inlet and the fluidic outlet and is disposed on the second chamber body of the membrane chamber.

2. The thermo-pneumatic peristaltic pump as claimed in claim 1, wherein the membrane chamber further comprises a connecting chamber body connecting the first chamber body to the second chamber body.

3. The thermo-pneumatic peristaltic pump as claimed in claim 1, wherein the heating base board further comprises at least one first electrode and at least one second electrode, and the heater is connected between the first and second electrodes.