Tool, container and method for the metering of liquids

Abstract

The application discloses a tool, container and method for liquid metering. The tool comprises a pressure changing component, a metering pipeline, an outflow channel, a liquid taking channel and a reset channel; a cut-off valve is arranged in the liquid taking channel and the reset channel, when the liquid level in the metering pipeline can no longer return to the 0 scale position, or there is excessive liquid over the 0 scale position which fails to be discharged, the outflow channel is closed, the reset channel is opened, the pressure changing component applies positive pressure, and the pressure changing cavity, gas and liquid in the metering pipeline are discharged to a specified position as much as possible, then the outflow channel is opened, the reset channel is closed, the pressure changing component applies negative pressure, and the liquid returns to the 0 scale line position, so that the liquid can be metered and taken again. The application can realize fast reset, and the components are simple and easy to operate.

Description

TECHNICAL FIELD

[0001] The present application relates to a tool, container and method for liquid metering, especially a tool, container and method for liquid metering with reset function. BACKGROUND

[0002] People often need to measure the volume of liquid in work and life, such as measuring various reagents, liquid pesticides, chemical raw materials, detergents, sterilization liquids, edible oils, liquid medicines, etc. Sometimes it needs to be accurate, and sometimes a vague value is acceptable. The traditional measurement tools, such as measuring cylinder, measuring cup and pipette, have many disadvantages when used, such as inconvenience, waste and pollution caused by contact between liquid and measurement tool, toxicity liquid volatilization, liquid oxidation by air, and loss affecting measurement accuracy during transfer, etc. Therefore, in recent years, new technologies such as self-measuring tools and containers have been developed to solve the above problems. Using tools and containers with self-measuring function can avoid the above-mentioned disadvantages.

[0003] However, after being used for many times, the existing self-measuring tools and containers may not be able to return to the 0 scale position due to factors such as air tightness, operation force and operation speed, or liquid exceeding the 0 scale position cannot be discharged. At this time, not only the measurement accuracy will be disturbed, but also the operation convenience will be affected, which hinders the wide application of containers with self-measuring function.

[0004] People need a tool, container and method for liquid metering, which can be sensitive to operation and control, make the use process accurate and convenient every time, and the structure is as simple as possible, which is suitable for large-scale promotion. SUMMARY

[0005] In order to solve the problems existing in the prior art, the present application provides a tool for liquid metering. The tool comprises a pressure changing component, a measuring pipeline, an outflow channel, a liquid taking channel and a reset channel; wherein the pressure changing component can generate positive and negative pressure in a pressure changing cavity, the pressure changing cavity is connected to the 0 scale end of the measuring pipeline; the pressure changing component is provided with an opening for discharging internal liquid; the end of the measuring pipeline is connected to the liquid taking channel, the outflow channel and the reset channel; the liquid taking channel is provided with a one-way flow device that can be connected to the measuring pipeline; the outflow channel is provided with a shut-off valve and a one-way flow device that can be connected to the outflow channel outlet; the reset channel is provided with a shut-off valve.

[0006] The tool for liquid metering and taking out is provided with a reset channel and a cut-off valve arranged in the taking-out channel and the reset channel. When the liquid level in the metering pipeline can no longer return to the 0 scale position or the excessive liquid over the 0 scale position fails to be discharged, the outflow channel is closed, the reset channel is opened, the pressure changing component applies positive pressure, the pressure changing cavity, the gas and liquid in the metering pipeline are discharged to a designated position (usually back to the liquid container), then the outflow channel is opened, the reset channel is closed, the pressure changing component applies negative pressure, and the liquid returns to the 0 scale position (the predetermined setting state), so that the liquid can be metered and taken out again. The quick reset, simple component and easy operation are one of the main advantages of the tool for liquid metering and taking out.

[0007] On the other hand, the excessive liquid enters the pressure changing cavity through the pressure change in the pressure changing cavity, so that the liquid in the metering pipeline is filled, positioned and metered and taken out, the operation is simple, the metering is convenient, the taking-out process does not rely on external tools, and the liquid waste, pollution, oxidation, volatilization and moisture absorption can be prevented.

[0008] The tool for liquid metering and taking out can make the cut-off valve arranged in the outflow channel and the reset channel be a three-way valve which can optionally close any branch and open another branch. By using the three-way valve, the opening and closing operation of the cut-off valve in the outflow channel and the reset channel is more convenient.

[0009] The tool for liquid metering and taking out can make the one-way flow device arranged in the outflow channel be arranged in the total branch section of the three-way valve or the branch section leading to the outflow port of the outflow channel.

[0010] The tool for liquid metering and taking out can make the one-way flow devices arranged in the taking-out channel and the outflow channel be the same valve which opens and closes the outflow channel and the taking-out channel through the movement of the valve core. This can further simplify the structure of the tool for liquid metering and taking out.

[0011] The tool for liquid metering and taking out can make the pressure changing component be a cylinder and a piston which can reciprocate in the cylinder, the opening is located on the wall of the cylinder, the piston can reach or pass through the opening, and the liquid flowing out of the opening is recycled to a designated position by the backflow channel. This structure can make the excessive liquid be recycled and integrated in the pressure changing operation, so that the pressure changing process is clear in stages and the hand feeling is better.

[0012] The tool for liquid metering and taking out can make the maximum volume of the liquid contained in the cylinder when the piston is located at the opening position not be less than two-thirds of the total volume of the cylinder. The cylinder contains part of the liquid, reduces the total amount of gas in the cylinder, and can improve the pressure changing sensitivity.

[0013] For the purpose of optimizing structure and improving operation, the tool for liquid metering and taking can make the piston be located horizontally or obliquely below the cylinder. For the purpose of simplifying structure, the tool for liquid metering and taking can make the return channel and the reset channel be combined.

[0014] The present application also relates to a container comprising the tool for liquid metering and taking. The container comprising the tool for liquid metering and taking has the advantages of simple structure, convenient operation, sensitive reaction, convenient positioning and metering, prevention of liquid waste, pollution, oxidation, evaporation and moisture absorption, etc. during taking operation, which is convenient for liquid product manufacturers and users.

[0015] The present application also relates to a method for liquid metering and taking, which comprises the following operations:

[0016] During conventional taking, the outlet channel cutoff valve is opened and the reset channel cutoff valve is closed, and then:

[0017] A when liquid needs to be taken out, the pressure changing component generates positive pressure in the pressure changing cavity, applies positive pressure to the 0 scale end of the metering pipe connected therewith, and the gas in the pressure changing cavity enters the metering pipe to push the liquid in the metering pipe to flow out through the outlet channel;

[0018] B the liquid gas interface at the 0 scale end of the metering pipe moves a distance corresponding to the metered out amount since the pressure is increased;

[0019] C after taking, the pressure changing component generates negative pressure in the pressure changing cavity, applies negative pressure to the 0 scale end of the metering pipe connected therewith, and the liquid to be taken enters the end of the metering pipe along the liquid taking channel;

[0020] D after the liquid to be taken fills the metering pipe, the excess liquid over the 0 scale end of the metering pipe enters the pressure changing cavity; when the opening provided on the pressure changing component is opened, the excess liquid with a liquid level higher than the opening flows out of the pressure changing cavity;

[0021] When the liquid in the metering pipe and / or the pressure changing cavity is too much or too little, the liquid level is not at the 0 scale line, and reset is needed:

[0022] E the outlet channel is closed, the reset channel is opened, and the pressure changing component generates positive pressure in the pressure changing cavity to remove the liquid and gas in the pressure changing cavity along the reset channel to the maximum extent;

[0023] F subsequently, the reset channel is closed, the pressure changing component generates negative pressure in the pressure changing cavity, the liquid enters the metering pipe along the liquid taking channel, reaches the 0 scale end or a small amount of liquid overflows the 0 scale end to enter the pressure changing cavity;

[0024] G the metering reset is completed, and the next taking can be performed.

[0025] The liquid metering method has the advantages of simple operation, convenient positioning and metering, high operation sensitivity, etc. It is suitable for daily use of ordinary residents, industrial production metering application, and precise metering use of researchers; the piston movement can be manually pushed and pulled, or can be driven by electricity. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a structural schematic diagram of the liquid metering tool according to embodiment 1;

[0027] Figure 2 is a structural schematic diagram of the liquid metering container according to embodiment 2;

[0028] Figure 3 is a partial enlarged view of the turning valve of the liquid metering container according to embodiment 2;

[0029] Figure 4 is a structural schematic diagram of the liquid metering container according to embodiment 3. DETAILED DESCRIPTION

[0030] Embodiment 1

[0031] Figure 1 is a structural schematic diagram of a liquid metering tool according to embodiment 1. The metering tool includes a variable pressure chamber 1, a piston 2, an operating rod 3, a metering pipeline 4, a liquid taking channel 5, an outflow channel 6, a reset channel 7, an opening 8, and a backflow channel 13. The piston 2 is located at the lower left of the variable pressure chamber 1, the 0 scale end of the metering pipeline 4 is connected to the upper part of the variable pressure chamber 1, the opening 8 is located in the upper middle part of the horizontal position of the variable pressure chamber 1, and penetrates the cavity wall of the variable pressure chamber 1. When the piston 2 reciprocates, it can pass through the opening 8 and reach the lower left side of the opening 8. When the piston 2 is located at the opening 8, the inside and outside of the variable pressure chamber 1 are communicated, and the maximum volume of liquid that can be contained in the variable pressure chamber 1 is two-thirds of the total volume of the variable pressure chamber. The semi-cylindrical recovery device 14 can collect and recover the liquid overflowing from the opening 8, and flow back to the liquid taking place through the backflow channel 13. The metering pipeline 4 has a scale, and the amount of outflowing liquid is displayed according to the distance of the liquid-gas interface moving at the 0 scale end of the metering pipeline 4.

[0032] The end of the measuring pipe 4 is connected to the liquid taking channel 5, the outflow channel 6 and the reset channel 7. The one-way flow device 9 in the liquid taking channel 5 allows liquid to flow into the measuring pipe 4 from the liquid taking position. The one-way flow device 10 in the outflow channel 6 allows liquid to flow out of the measuring pipe 4 along the outflow channel 6. The outflow channel 6 and the reset channel 7 are provided with a three-way valve 11, which is provided with a rotatable handle 12 that can select to close any branch and open the other branch; the outflow channel 6 and the reset channel 7 are branched after passing through the three-way valve 11. The one-way flow device 10 is located on the branch of the three-way valve 11 leading to the outflow channel 6. When the reset channel 7 is open and the variable pressure chamber 1 is pressurized, the reset channel 7 can guide the liquid and / or gas in the variable pressure chamber 1 and the measuring pipe 4 to the outflow of the reset channel 7.

[0033] The plug 15 provided with the liquid taking channel 5, the reset channel 7 and the return channel 13 can fix the measuring tool on the container containing the liquid to be taken out.

[0034] When the piston 2 moves outward and the variable pressure chamber 1 is under negative pressure, the liquid in the measuring pipe 4 flows towards the variable pressure chamber 1, and the liquid beyond the 0 scale end enters the variable pressure chamber 1; when the piston 2 moves beyond the position of the opening 8, external gas enters the variable pressure chamber 1 from the opening 8, the negative pressure disappears, and the liquid stops moving; when the piston 2 moves inward beyond the opening 8, the variable pressure chamber 1 is under positive pressure, the liquid in the measuring pipe 4 flows outward, and the gas in the variable pressure chamber 1 or the gas and liquid in the variable pressure chamber 1 enter the measuring pipe 4; the distance that the liquid-gas interface at the 0 scale end moves from the start of the positive pressure measures the amount of liquid flowing out.

[0035] The method of measuring the liquid taken out by the measuring tool is as follows:

[0036] When the liquid is taken out normally, the rotatable handle 12 is rotated to open the outflow channel 6 and close the reset channel 7, and then:

[0037] A When the liquid needs to be taken out, the operating rod 3 is pushed inward, the piston 2 moves upward to the right, the variable pressure chamber 1 generates positive pressure, applies positive pressure to the 0 scale end of the measuring pipe 4 connected thereto, the one-way flow device 10 in the outflow channel 6 opens, and the gas in the variable pressure chamber 1 first enters the measuring pipe 4 and pushes the liquid in the measuring pipe to flow out through the outflow channel 6; if the positive pressure continues to be applied, the liquid in the variable pressure chamber 1 enters the measuring pipe 4 and continues to push the liquid in the measuring pipe 4 to flow out;

[0038] B The distance that the liquid-gas interface at the 0 scale end in the measuring pipe 4 moves from the start of the positive pressure measures the amount of liquid flowing out.

[0039] CAfter the liquid is taken, the operating rod 3 is pulled outwards, the piston 2 moves to the left and downwards, the pressure chamber 1 generates negative pressure, the negative pressure is applied to the 0 scale end of the measuring pipe 4, the one-way flow device 9 in the liquid taking channel 5 is opened, and the liquid to be taken flows into the end of the measuring pipe 4 along the liquid taking channel 5;

[0040] DWhen the liquid to be taken fills the measuring pipe 4, the excess liquid over the 0 scale end of the measuring pipe 4 enters the pressure chamber 1; when the opening 8 arranged on the pressure changing part is located at the right upper side of the piston 2, the excess liquid with a liquid level higher than the opening flows out of the pressure chamber 1;

[0041] When the liquid in the measuring pipe 4 and / or the pressure chamber 1 is too much or too little, the liquid level is not at the 0 scale line, and the reset is needed:

[0042] EThe rotatable wrench 12 is rotated to close the outflow channel 6, open the reset channel 7, and push the operating rod 3 inwards, so that the piston 2 moves to the right and upwards, the pressure chamber 1 generates positive pressure, and the liquid and gas in the pressure chamber 1 are removed along the reset channel 7 to the maximum extent;

[0043] FSubsequently, the rotatable wrench 12 is rotated to close the reset channel and open the outflow channel 6, the operating rod 3 is pulled outwards, the piston 2 moves to the left and downwards, the pressure chamber 1 generates negative pressure, the liquid flows into the measuring pipe 4 along the liquid taking channel 5, and reaches the 0 scale end or a small amount of liquid overflows the 0 scale end and enters the pressure chamber 1;

[0044] GThe measurement reset is completed, and the next taking can be performed.

[0045] Compared with the traditional liquid volume measurement tool, the measurement tool and the measurement method are sensitive, convenient, fast and accurate due to the liquid stored in the pressure chamber 1.

[0046] As a deformation of the embodiment, the end of the reset channel 7 and the backflow channel 13 can share one channel.

[0047] Embodiment 2

[0048] Figure 2 The structure schematic diagram of the liquid measurement and taking container according to embodiment 2 is shown, Figure 3 is a partial enlarged view of the turning valve 12 of the liquid measurement and taking container according to embodiment 2.

[0049] The liquid measurement and taking container includes a pressure chamber 1, a piston 2, a connecting rod 3, a measuring pipe 4, a liquid taking channel 5, an outflow channel 6, a reset channel 7, an opening 8, a backflow channel 11, a turning valve 12 and a container main body 13.

[0050] Wherein, the piston 2 is located at the right side of the pressure changing cavity 1, the 0 scale end of the measuring pipe 4 is connected to the upper part of the bottom of the pressure changing cavity 1, the opening 8 is located at the middle upper part of the horizontal position of the pressure changing cavity 1, and the piston 2 can move through the opening 8 and reach the right side of the opening 8 when the piston 2 reciprocates. When the piston 2 is located at the opening 8, the inside and outside of the pressure changing cavity 1 are communicated, and the maximum volume of the liquid contained in the pressure changing cavity 1 is two-thirds of the total volume of the pressure changing cavity 1. The liquid exceeding the volume will overflow from the opening 8. The liquid overflowing from the opening 8 flows back into the container body 13 through the backflow channel 11. The measuring pipe 4 is provided with a scale, and the volume of the liquid flowing out is displayed according to the distance of the liquid-gas interface moving at the 0 scale end of the measuring pipe 4.

[0051] The end of the measuring pipe 4 is connected to the liquid taking channel 5 and the converging channel 10 through the diversion valve 12. The diversion valve 12 comprises a valve body 15, a valve core 14 and a reset spring 16. The valve core 14 is provided with an internal channel 17, and the internal channel 17 comprises a vertical part connected to the measuring pipe 4 and a horizontal part connected to the side wall of the valve core 14. When the pressure changing cavity 1 is under positive pressure, the valve core 14 moves downward, and the horizontal part of the internal channel 17 is connected to the converging channel 10 through the opening in the valve body 15. When the pressure changing cavity 1 is under negative pressure, the valve core 14 moves upward, and the horizontal part of the internal channel 17 is connected to the liquid taking channel 5 through the opening in the valve body 15. The reset spring 16 makes the valve core 14 stay in the middle position when there is no pressure, and the horizontal part of the internal channel 17 is not connected to the liquid taking channel 5 and the converging channel 10. The opening 18 makes the valve core 14 move up and down smoothly in the cavity of the valve body 15.

[0052] The converging channel 10 is the common initial segment of the flowing-out channel 6 and the reset channel 7. Then, the flowing-out channel 6 and the reset channel 7 are divided through the three-way valve 19 and connected to the flowing-out channel 6 outlet and the container body 13 respectively.

[0053] The three-way valve 19 can be manually operated by the handle 20 to select the closing of the reset channel 7 and the opening of the flowing-out channel 6, or the opening of the reset channel 7 and the closing of the flowing-out channel 6.

[0054] The method for measuring and taking out the liquid of the measuring container is as follows:

[0055] When the container is used normally, the handle 20 of the three-way valve 19 is rotated to open the flowing-out channel 6 and close the reset channel 7, and then:

[0056] When the liquid needs to be taken out, the operating rod 3 is pushed inward, the piston 2 moves to the left, the pressure changing cavity 1 generates positive pressure, the positive pressure is applied to the 0 scale end of the measuring pipe 4 connected to the pressure changing cavity 1, the horizontal part of the internal channel 17 is connected to the converging channel 10, the gas in the pressure changing cavity 1 first enters the measuring pipe 4 and pushes the liquid in the measuring pipe to flow out through the flowing-out channel 6; the positive pressure is continuously applied, and then the liquid in the pressure changing cavity 1 enters the measuring pipe 4 and continuously pushes the liquid in the measuring pipe 4 to flow out;

[0057] B From the beginning of the pressurization, the distance of the liquid-gas interface from the 0 scale end of the measuring pipe 4 is measured to determine the amount of liquid flowing out;

[0058] C After use, pull the operating rod 3 outward, and the piston 2 moves to the right, the pressure chamber 1 generates negative pressure, and applies negative pressure to the 0 scale end of the measuring pipe 4 connected thereto, the valve core 14 moves upward, the transverse part of the internal passage 17 is connected with the liquid taking passage 5, and the liquid to be taken flows into the end of the measuring pipe 4 from the container main body 13;

[0059] D After the liquid to be taken fills the measuring pipe 4, the excess liquid beyond the 0 scale end of the measuring pipe enters the pressure chamber 1; when the opening 8 provided on the pressure changing part is located on the left side of the piston 2, the excess liquid higher than the opening flows out of the pressure chamber 1;

[0060] When the liquid in the measuring pipe 4 and / or the pressure chamber 1 is too much or too little, and the liquid level is not at the 0 scale line, it needs to be reset:

[0061] E Turn the handle 20 of the three-way valve 19 to close the outflow passage 6 and open the reset passage 7, and push the operating rod 3 to the left, and the piston 2 moves to the left, the pressure chamber 1 generates positive pressure, the transverse part of the internal passage 17 is connected with the confluence passage 10, and the liquid and gas in the pressure chamber 1 are discharged to the container main body 13 along the reset passage 7 to the maximum;

[0062] F Then, turn the handle 20 of the three-way valve 19 to close the reset passage 7 and open the outflow passage 6, and pull the operating rod 3 outward, and the piston 2 moves to the right, the pressure chamber 1 generates negative pressure, the transverse part of the internal passage 17 is connected with the liquid taking passage 5, and the liquid enters the measuring pipe 4 along the liquid taking passage 5 to the 0 scale end or a small amount of liquid beyond the 0 scale end enters the pressure chamber 1;

[0063] G The measurement reset is completed, and the next taking can be performed.

[0064] This kind of measuring container also has the characteristics of sensitivity, convenience, speediness and accuracy.

[0065] Example 3

[0066] Figure 4 The structure diagram of a liquid measuring and taking container according to Example 3 is shown. The container includes a pressure chamber 1, a piston 2, a connecting rod 3, a motor 15, a measuring pipe 4, a liquid taking passage 5, an outflow passage 6, a reset passage 7, an opening 8, a backflow passage 9 and a container main body 14.

[0067] Wherein, the piston 2 is located at the right side of the pressure changing cavity 1, the opening 8 is located at the lower right side of the pressure changing cavity 1 and penetrates the cavity wall of the pressure changing cavity 1; when the piston 2 moves to the right, it can reach or pass the opening 8. The liquid overflowing from the opening 8 flows back into the container main body 14 through the backflow channel 9. The motor 15 can push and pull the piston 2 through the connecting rod 3.

[0068] The 0 scale end of the metering pipe 4 is connected to the upper part of the bottom of the pressure changing cavity 1, and the metering pipe 4 has a scale. The amount of the liquid flowing out can be displayed according to the distance of the liquid-gas interface moving at the 0 scale end of the metering pipe 4. The end of the metering pipe 4 is connected to the liquid taking channel 5, the liquid flowing-out channel 6 and the reset channel 7 respectively. The one-way flow device 10 in the liquid taking channel 5 allows the liquid to flow from the container main body 1 into the metering pipe 4; the one-way flow device 11 in the liquid flowing-out channel 6 allows the liquid to flow out from the metering pipe 4, and the shutoff valve 12 can open and close the liquid flowing-out channel 6; the shutoff valve 13 in the reset channel 7 can open and close the reset channel 7.

[0069] The method for measuring and taking out the liquid of the measuring container is as follows:

[0070] When the measuring container is used normally, the shutoff valve 12 in the liquid flowing-out channel 6 is opened, and the shutoff valve 13 in the reset channel 7 is closed, and then:

[0071] A When the liquid needs to be taken out, the motor 15 pushes the operating rod 3 inward, the piston 2 moves to the left, the pressure changing cavity 1 generates positive pressure, applies positive pressure to the 0 scale end of the metering pipe 4 connected thereto, the one-way flow device 11 in the liquid flowing-out channel 6 is opened, the gas in the pressure changing cavity 1 enters the metering pipe 4, and pushes the liquid in the metering pipe 4 to flow out through the liquid flowing-out channel 6;

[0072] B The distance of the liquid-gas interface moving at the 0 scale end of the metering pipe 4 measures the amount of the liquid flowing out since the pressure is increased;

[0073] C After the liquid is taken out, the motor 15 pulls the operating rod 3, the piston 2 moves to the right, the pressure changing cavity 1 generates negative pressure, applies negative pressure to the 0 scale end of the metering pipe 4 connected thereto, and the one-way flow device 10 in the liquid taking channel 5 is opened, so that the liquid to be taken out enters the metering pipe 4 from the container main body 14;

[0074] D After the liquid to be taken out fills the metering pipe 4, the excess liquid over the 0 scale end of the metering pipe 4 enters the pressure changing cavity 1; when the opening 8 provided on the pressure changing component is located at the left side of the piston 2, the excess liquid flows out of the pressure changing cavity 1;

[0075] When the liquid in the metering pipe 4 is too little and the liquid level is not at the 0 scale line, and the reset is needed:

[0076] E Close the outlet passage 6 shut-off valve 12, open the reset passage 7 shut-off valve 13, the motor 15 pushes the operating rod 3 to the left, the piston 2 moves to the left, the variable pressure chamber 1 generates positive pressure, the one-way flow device 11 opens, the liquid and gas in the variable pressure chamber 1 are discharged to the container body 14 along the reset passage 7 to the maximum extent;

[0077] F Then, close the reset passage 7 shut-off valve 13, the motor 15 pulls the operating rod 3 outward, the piston 2 moves to the right, the variable pressure chamber 1 generates negative pressure, the one-way flow device 10 opens, the liquid enters the metering pipe 4 along the liquid taking passage 5, reaches the 0 scale end or a small amount of liquid crosses the 0 scale end to enter the variable pressure chamber 1;

[0078] G The metering reset is completed, and the next taking can be performed.

[0079] The metering container is also sensitive, convenient, fast and accurate.

[0080] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions, variations and combinations can be made to these embodiments without departing from the principles and spirit of the present application. The scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A tool for the metered taking of a liquid, characterized in that The tool comprises a pressure changing component, a metering pipe, an outflow channel, a liquid taking channel and a reset channel. The pressure changing component can generate positive and negative pressure in a pressure changing cavity, and the pressure changing cavity is connected to the 0 scale end of the metering pipe. The pressure changing component is provided with an opening for discharging internal liquid. The end of the metering pipe is connected to the liquid taking channel, the outflow channel and the reset channel. The liquid taking channel is provided with a one-way flow device which can be connected to the metering pipe. The outflow channel is provided with a one-way flow device which can be connected to the outflow channel outlet. The outflow channel and the reset channel are provided with a shut-off valve. The pressure changing component is a cylinder and a piston which can move back and forth in the cylinder, the opening is located on the cylinder wall, the piston can reach or pass the opening, and the liquid flowing out of the opening is recycled to a designated position by a return channel. The shut-off valve provided in the outflow channel and the reset channel is a three-way valve which can optionally close any branch while opening another branch.

2. A tool for the metered taking of liquid according to claim 1, characterized in that The one-way flow device provided in the outflow channel is located in the main branch of the three-way valve or the branch leading to the outflow channel outlet.

3. The tool for the metered taking of liquid according to claim 1, characterized in that The one-way flow devices provided in the liquid taking channel and the outflow channel are the same valve which opens and closes the outflow channel and the liquid taking channel by moving the valve core.

4. The tool for the metered taking of liquid according to claim 1, characterized in that When the piston is located at the opening position and the pressure changing cavity is connected to the outside, the maximum volume of liquid contained in the cylinder is not less than two-thirds of the total volume of the cylinder.

5. The tool for the metered taking of liquid according to claim 1, characterized in that The piston is located at the horizontal side or oblique lower side of the cylinder.

6. The tool for the metered taking of a liquid according to claim 1, characterized in that The return channel and the reset channel are merged at the end.

7. A container characterized in that The tool for liquid metering and taking comprises the tool for liquid metering and taking of claim 1.

8. A method for liquid metering based on the tool for liquid metering according to claim 1, characterized in that The tool comprises the following operations: During normal taking, the outflow channel is opened and the reset channel is closed, and then: A When liquid needs to be taken out, the pressure changing component generates positive pressure in the pressure changing cavity, applies positive pressure to the 0 scale end of the metering pipe connected thereto, and the gas in the pressure changing cavity enters the metering pipe to push the liquid in the metering pipe to flow out through the outflow channel; B The distance of the liquid-gas interface at the 0 scale end in the metering pipe from the start of pressurization is the amount of metered outflow; C After taking, the pressure changing component generates negative pressure in the pressure changing cavity, applies negative pressure to the 0 scale end of the metering pipe connected thereto, and makes the liquid to be taken enter the end of the metering pipe along the liquid taking channel; D After the liquid to be taken fills the metering pipe, the excess liquid beyond the 0 scale end of the metering pipe enters the pressure changing cavity; when the opening provided on the pressure changing component is opened, the excess liquid with a liquid level higher than the opening flows out of the pressure changing cavity; When the liquid in the metering pipe and / or the pressure changing cavity is too much or too little, the liquid level is not at the 0 scale line, and reset is needed: E The outflow channel is closed and the reset channel is opened, the pressure changing component generates positive pressure in the pressure changing cavity, and the liquid and gas in the pressure changing cavity are maximally discharged along the reset channel; F Subsequently, the reset channel is closed, the pressure changing component generates negative pressure in the pressure changing cavity, liquid enters the metering pipe along the liquid taking channel, and reaches the 0 scale end or a small amount of liquid beyond the 0 scale end enters the pressure changing cavity; G The metering reset is completed, and the next taking is performed.

Images