CN1936412A

CN1936412A - Self-boosted liquid-supplying system

Info

Publication number: CN1936412A
Application number: CN 200610122736
Authority: CN
Inventors: 徐进良; 岑继文
Original assignee: Guangzhou Institute of Energy Conversion of CAS
Current assignee: Guangzhou Institute of Energy Conversion of CAS
Priority date: 2006-10-13
Filing date: 2006-10-13
Publication date: 2007-03-28
Anticipated expiration: 2026-10-13
Also published as: CN100434790C

Abstract

This invention provides a pressure self-increasing and liquid-supply system meeting the requirement of light quality and small power loss of micro-fluid devices including a fluid storage tank, a gas generator, a pressure sensor and a pressure controller, in which, the liquid storage tank is connected with the gas generator via a pipeline connected to the pressure sensor, the pressure controller is connected with the sensor and the generator via circuit, a gas generator includes a closed container containing a drug drum with solid chemical drugs contacted with a heater closely, the lead of which is led to outside of the container and connected to the pressure controller, the gas generator uses the heater to analyze the drugs and generate gas and the pressed gas preses the needed liquid into a fluid device to supply fluid.

Description

Self-pressurization liquid supply system

Technical Field

The invention relates to a self-pressurizing liquid supply system for a fluid device, in particular to a self-pressurizing liquid supply system for a micro-fluid device.

Background

In recent years, with the development of micro-electro-mechanical systems (MEMS) technology, many microfluidic devices, such as biochips, micro fuel cells for portable electronic products such as notebook computers and mobile phones, micro liquid fuel thrusters for micro satellites, etc., have emerged, which require relatively small structures, sizes and flow rates. These microfluidic devices generally require light weight and low power consumption. To make them a complete and independent device, a self-pressurized liquid supply system with light weight and low power consumption must be equipped with it. The pressure source of the general pressure-driven fluid device is provided by an air compressor, various electric pumps or high-pressure nitrogen cylinders, and the like, the pressure source equipment has complex structure, heavier weight and difficult miniaturization, and the high-pressure nitrogen cylinder has heavy structure, high initial pressure and prominent air leakage problem and can be used only by good pressure reduction equipment. The MEMS micropump developed in recent years has the advantages of complex structure, difficult processing, limited supercharging capacity and further improved performance. Therefore, there is a need to develop a novel pressure generating device to meet the requirements of the development of microfluidic devices.

Disclosure of Invention

The invention aims to provide a self-pressurization liquid supply system which can meet the requirements of light weight and low power consumption of a microfluid device.

The purpose of the invention can be realized by the following technical scheme:

the self-pressurization liquid supply system mainly comprises two parts: a gas generator and a liquid storage tank, wherein the liquid storage tank can be spherical or in other shapes. And a pressure sensor and a pressure controller. The liquid storage tank is communicated with the gas generator through a pipeline, the pipeline is communicated with the pressure sensor, and the pressure controller is connected with the pressure sensor and the gas generator through a circuit.

The gas generator works on the principle that an electric heater is used for heating ammonium bicarbonate (NH)₄HCO₃) (or other solid chemicals which generate gas through thermal decomposition, such as sodium bicarbonate, azodiisobutyronitrile and the like) generate gas through thermal decomposition. The chemical reaction formula is as follows:

the liquid storage tank can be divided into two halves by a loose and elastic diaphragm, one side of the diaphragm stores liquid or gas required by the fluid device, the other side of the diaphragm is communicated with the gas generator, and the required liquid is pressed into the fluid device by the pressure gas generated by the gas generator, so that the aim of supplying liquid is fulfilled. Of course, the diaphragm is not required to be arranged in the application occasions where the liquid is not polluted by ammonia gas and carbon dioxide. However, in order to reduce the amount of the drug, the tank may be preliminarily filled with oxygen and carbon dioxide and saturated in the liquid.

The pressure inside the system can be detected by a pressure sensor, and is controlled by a pressure controller according to the magnitude of the pressure signal to control the on-off of the power supply of the electric heater of the gas generator. In this way, a certain pressure can be set on the control circuit of the system,when the air pressure in the system is less than the set value, the heater is powered on, NH₄HCO₃The decomposition starts to produce gas, raising the pressure in the system. When the pressure exceeds the set value, the heater power supply is cut off, and the set pressure is maintained.

Due to NH₄HCO₃The medicine which is tightly pressed on the iron heater is decomposed and disappears firstly, if certain measures are not taken, the residual medicine and the heater can not be in mutual contact, the heat conduction is poor, and serious heat dissipation loss is caused. Therefore, the medicine barrel is jacked up by the spring arranged at the bottom of the medicine barrel, so that the rest medicine is always in close contact with the heater.

The invention has light weight, low power consumption and convenient use, can meet the development requirement of a microfluid device and has good application prospect.

Drawings

FIG. 1 is a schematic diagram of a self-pressurizing liquid supply system according to the present invention;

FIG. 2 is a cross-sectional view of the gas generator 2 of FIG. 1;

fig. 3 is a sectional view of the tank 1 of fig. 1;

Detailed Description

Referring to fig. 1, the present invention mainly comprises: a liquid storage tank 1, a gas generator 2, a pressure sensor 3 and a pressure controller 4. The liquid storage tank 1 is communicated with the gas generator 2 through a pipeline which is communicated with the pressure sensor 3, and the pressure controller 4 is connected with the pressure sensor 3 and the gas generator 2 through a circuit. When a part of the liquid in the tank 1 is consumed, the pressure sensor 3 senses the pressure reduction of the tank, the pressure signal is transmitted to the pressure controller 4, the controller 4 controls the gas generator 2 to heat to generate gas, and the pressure is increased accordingly. When the gas generator 2 generates excessive gas and the pressure is higher than the set value, the pressure controller 4 cuts off the power supply of the heater 10 in the gas generator 2 and stops heating to generate gas. Thereby maintaining a certain pressure in the tank 1.

Referring to fig. 2, the gas generator 2 includes a closed container 11, a medicine-containing barrel 14 is provided in the closed container 11, a solid chemical 13 is provided in the medicine-containing barrel 14, a heater 10 is in close contact with the solid chemical 13, and a power supply lead 7 of the heater 10 is led out of the closed container 11 and connected to a pressure controller 4. The basic working principle of the gas generator 2 is that the heater 10 heats the solid chemical 13 which is easy to decompose and generate gas, and the chemical 13 is decomposed to generate gas after being heated to a certain degree. The chemical 13 may have a composition of NH₄HCO₃，NH₄HCO₃When heated to about 80 deg.f, carbon dioxide, ammonia and water are decomposed.

Due to NH₄HCO₃The solid is completely decomposed without residue, and a spring 15 can be arranged at the bottom of the medicine charging barrel 14, when the medicine contacted with the heater 10 is decomposed and disappeared, the medicine charging barrel 14 is jacked up due to the elastic force of the spring 15, so that the rest medicine is continuously and tightly contacted with the heater 10. Due to purchased NH₄HCO₃Is generally a soft white powder so that NH can be added to the cartridge 14₄HCO₃The powder is tightly pressed, so that the space of the medicine charging barrel 13 can be fully utilized, and more medicines can be loaded; secondly, the stress of the tight medicine against the spring does not cause the heater 10 to be openedIt will initially sink deep into the medication 13.

The heater 10 is arranged in the closed container 11, and the power supply lead 7 is required to be led out of the container, but the air tightness of the container is ensured. Therefore, certain special structures and measures must be taken to achieve this function: between the heater 10 and the top cover of the container 11 is sandwiched a heat insulating and sealable material 9, which may be polytetrafluoroethylene, capable of withstanding high temperatures of two hundred to three hundred degrees celsius. The heater 10, the heat insulating sealing material 9 and the top cover boss of the container 11 are connected by the elongated bolt 8 and screwed tightly to achieve the sealing effect. The container 11 top cover is provided with a boss for processing a dead hole connecting bolt, because if the through hole is provided, leakage is easy to generate. The lead 7 of the heater 10 can be led out by punching two small holes on the top cover of the heat insulating material 9 and the container 11 without affecting the air tightness of the container.

The housing, i.e. the container 11, of the gas generator is generally made of metal, such as stainless steel, titanium alloy, aluminum alloy, etc., which has high thermal conductivity and is easy to dissipate heat, so that it is necessary to cover the inner wall with a layer of insulating material 12, such as polytetrafluoroethylene in particular.

In addition, due to NH₄HCO₃The solids themselves are readily volatilized by heating and a small portion of the solids condense on the insulating material 12 after a period of operation. Therefore, a certain gap is reserved between the inner wall of the heat insulating material 12 and the outer wall of the medicine charging barrel 14, so that the medicine charging barrel 14 can be smoothly pushed under the action of the spring 15.

Referring to fig. 3, in one embodiment of the liquid reservoir of the present invention, the shell may be spherical, which advantageously minimizes the surface area of the spherical shell for the same volume and reduces the weight of the reservoir. The fuel tank is particularly suitable for occasions with higher requirements on weight, such as a fuel tank of a microsatellite. The middle of the spherical shell is separated by a flexible diaphragm 5 which can be a rubber film or a polypropylene film. The membrane is used for separating upper and lower gas and liquid, and the liquid is prevented from being polluted by carbon dioxide or ammonia gas. The other advantage is that the diaphragm is arranged, so that gas can not be dissolved in liquid, the effective and rapid pressurization of the system is facilitated, and the use amount of medicines is reduced. In the application as a satellite fuel tank, the membrane 5 ensures that gas and liquid remain separated in a weightless condition, ensuring that only liquid fuel can be discharged through the outlet 16.

Of course, the separator 5 may be omitted in applications where ammonia and carbon dioxide are not a concern for contaminating the liquid. However, in order toreduce the amount of the drug, the tank 1 may be preliminarily filled with oxygen and carbon dioxide and saturated in the liquid.

The pressure controller 4 can input voltage signals, and the output of the relay controls the on-off of the heater power supply. The pressure sensor 3 can be an MEMS chip embedded on the inner wall of the pressure container, and can also be a common cylindrical sensor. The chip type can greatly reduce the mass of the system.

Claims

1. The self-pressurization liquid supply system is characterized by comprising a liquid storage tank (1), a gas generator (2), a pressure sensor (3) and a pressure controller (4), wherein the liquid storage tank (1) is communicated with the gas generator (2) through a pipeline, the pipeline is communicated with the pressure sensor (3), and the pressure controller (4) is connected with the pressure sensor (3) and the gas generator (2) through a circuit; the gas generator (2) comprises a closed container (11), a medicine charging barrel (14) is arranged in the closed container (11), solid chemicals (13) are filled in the medicine charging barrel (14), the heater (10) is in close contact with the solid chemicals (13), and a power supply lead (7) of the heater (10) is led out of the closed container (11) and is connected with the pressure controller (4).

2. The self-pressurized liquid supply system as claimed in claim 1, wherein said tank (1) is spherical.

3. The self-pressurizing liquid supply system according to claim 1 or 2, wherein the tank (1) is divided into two halves by a loose and elastic diaphragm (5), one side of the diaphragm (5) stores liquid or gas required for the fluid device, and the other side is communicated with the gas generator (2), and the gas generator (2) generates pressure gas to press the required liquid into the fluid device for the purpose of liquid supply.

4. The self-pressurized liquid supply system as claimed in claim 3, wherein the diaphragm (5) is a rubber film or a acrylic film.

5. The self-pressurized liquid supply system as claimed in claim 1, characterized in that said solid chemical (13) is ammonium bicarbonate.

6. The self-pressurizing liquid supply system as set forth in claim 1, wherein a heat insulating sealing material (9) is interposed between the heater (10) and the top cover of the closed vessel (11), and the heater (10), the heat insulating sealing material (9) and the top cover of the closed vessel (11) are coupled by means of an elongated bolt (8).

7. The self-pressurized liquid supply system as claimed in claim 1 or 6, wherein a spring (15) is provided at the bottom of the cartridge (14).

8. The self-pressurized liquid supply system as claimed in claim 1, wherein the inner wall of said closed container (11) is covered with a heat insulating material (12).

9. The self-pressurized liquid supply system as claimed in claim 1, wherein the pressure controller (4) controls the power supply of the heater (10) to be turned on or off according to the magnitude of the pressure signal detected by the pressure sensor (3).

10. The self-pressurized liquid supply system as claimed in claim 1 or 9, wherein the pressure controller (4) is configured to provide a voltage signal input and a relay output to control the switching of the power supply to the heater (10).