A Marsh bottle instrument with adjustable pressure and its operating method

Abstract

This invention relates to a Marvin flask instrument and its operating method with adjustable pressure and vacuum, belonging to the field of Marvin flask testing instruments. It includes a Marvin flask body, an inlet pipe fixed to the body, one end of which extends into the cavity of the flask body, and the other end extending out. An inlet pipe valve is fixed to the inlet pipe. The flask body has a water inlet and a stopper. It also has a vacuum outlet. A vacuum device is connected to the flask body. A water outlet pipe is connected to the flask body, one end of which is connected to the water outlet, and the other end is connected to and communicates with a test cylinder. An external valve for opening and closing the water outlet pipe is fixedly connected to the water outlet pipe. The gas inside the Marvin flask body is extracted, and the liquid column in the inlet pipe completely enters the flask body, ensuring the pressure at the inlet pipe end is at standard atmospheric pressure, equal to the liquid surface pressure in the test cylinder, avoiding pressurized water intake.

Description

Technical Field

[0001] This invention belongs to the field of soil mechanics or soil science testing instruments, specifically relating to a Marvi bottle instrument with adjustable pressure and its operating method. Background Technology

[0002] A Marvin bottle is a constant-pressure elution bottle that maintains a constant flow rate and head. It is used in many soil mechanics or soil science experiments, such as providing a constant head for soil column tests to facilitate a series of soil sample or soil hydration tests. These tests are often lengthy and involve large amounts of water, and the water level in the Marvin bottle frequently becomes insufficient during the experiment, necessitating the addition of water.

[0003] like Figure 1 In existing Marvin flasks, when water is added, the valve on the outlet pipe opens to balance the gas pressure inside the flask, and water is then injected into the flask through the inlet pipe. After water is added, a liquid column remains in the inlet pipe. The pressure at the bottom of the inlet pipe (atmospheric pressure + liquid column pressure in the inlet pipe) is greater than the pressure at the water replenishment end inside the test tube (atmospheric pressure). Because of the presence of the liquid column pressure in the inlet pipe, the water in the Marvin flask always "pressurizes" the test tube, keeping the liquid level in the test tube slightly higher than the lower end of the inlet pipe (the liquid level in the test tube and the liquid level in the inlet pipe are equal), and cannot achieve "unpressurized water replenishment". Furthermore, as the water in the test tube decreases, the liquid level in the inlet tube also drops at the same height after the Marvin flask replenishes the water in the test tube. The pressure of the liquid column in the inlet tube gradually decreases. Therefore, the pressure exerted by the Marvin flask on the test tube during "pressurization and water replenishment" also gradually decreases, and the liquid level in the test tube gradually decreases, approaching the lower end of the inlet tube. This causes errors in the water replenishment process and affects the test results. Summary of the Invention

[0004] The present invention provides a Marvin bottle instrument and operating method with adjustable pressure and air extraction capability. Its purpose is to eliminate the liquid column in the air inlet tube of the Marvin bottle when water is injected into the Marvin bottle during the soil column test, thereby reducing test errors.

[0005] To achieve the above objectives, the present invention provides a Marviate bottle instrument with adjustable pressure and suction capability, comprising a Marviate bottle body, an air inlet pipe fixed to the Marviate bottle body, one end of the air inlet pipe extending into the cavity of the Marviate bottle body, and the other end of the air inlet pipe extending out of the Marviate bottle body; characterized in that an air inlet valve for opening and closing the air inlet pipe is fixed to the air inlet pipe; a water inlet communicating with the cavity of the Marviate bottle body is provided on the Marviate bottle body, and a bottle stopper for sealing the water inlet is provided on the Marviate bottle body; an air extraction port is provided on the Marviate bottle body, located above the air inlet pipe; an air extraction device is connected to the Marviate bottle body, and the air extraction device is connected to the cavity of the Marviate bottle body through the air extraction port; a water outlet is provided on the Marviate bottle body, and a water outlet pipe is connected to the Marviate bottle body, one end of the water outlet pipe communicating with the water outlet, and the other end of the water outlet pipe communicating with a test cylinder, and an external pipe valve for opening and closing the water outlet pipe is fixedly connected to the water outlet pipe.

[0006] Furthermore, the air inlet pipe includes a vertical pipe and a horizontal pipe. The vertical pipe is located in the cavity of the Marshall bottle body. One end of the horizontal pipe is connected to and communicates with the upper end of the vertical pipe, and the other end of the horizontal pipe extends out of the cavity of the Marshall bottle body from the side wall of the Marshall bottle body.

[0007] By setting the air inlet pipe into two parts, with the horizontal pipe extending from the side wall of the Marvin flask body, the vertical height of the air inlet pipe can be reduced. This results in a lower height of the liquid column reserved in the air inlet pipe compared to a vertical air inlet pipe. Only a small amount of gas needs to be drawn from the Marvin flask body to completely draw the liquid column in the air inlet pipe into the cavity of the Marvin flask body, reducing the difficulty of operation.

[0008] Furthermore, the air inlet valve is fixed on the horizontal tube and is located outside the cavity of the Martens bottle body.

[0009] The inlet valve is located outside the horizontal tube, allowing the tester to manually control it. If the inlet valve were located inside the Marvin flask, it would require electronic control. Manual control is more cost-effective than electronic control.

[0010] Furthermore, the water inlet is located above the air inlet pipe.

[0011] During water filling, water flows into the inlet by gravity. As long as the water flow does not completely block the inlet, the gas pressure inside the Marvin flask remains at standard atmospheric pressure. If the inlet is designed too low, an additional tool (pump) is needed to fill it with water, and the water will not flow out. Furthermore, the gas pressure inside the Marvin flask cannot be guaranteed to be at standard atmospheric pressure after filling. Therefore, placing the inlet above the air inlet is not only easy to implement but also ensures the correct gas pressure inside the Marvin flask.

[0012] The operating method of the Marsh bottle instrument with adjustable pressure and vacuum capability according to the present invention includes the following steps:

[0013] S1: Observe the liquid level in the Marshall bottle. When the liquid level is lower than the bottom of the vertical pipe, prepare to supply water to the Marshall bottle.

[0014] S2: Close the air inlet valve and the external pipe valve; remove the bottle stopper at the water inlet; fill the Marshall bottle with water through the water inlet, so that the liquid level in the Marshall bottle is higher than the lower end of the vertical pipe, and the liquid level in the Marshall bottle does not fill the cavity of the Marshall bottle.

[0015] S3: Plug the bottle cap into the water inlet; open the air inlet valve, and keep the external pipe valve closed;

[0016] S4: Use a vacuum device to extract the gas from the body of the Marvin flask, and the liquid column in the inlet pipe continuously flows into the body of the Marvin flask.

[0017] S5: Stop pumping air when the liquid column in the inlet pipe has just completely entered the Marshall bottle;

[0018] S6: Keep the intake pipe valve open and open the external pipe valve.

[0019] Beneficial effects:

[0020] When a liquid column is present in the inlet pipe, it exerts pressure on the lower end of the inlet pipe. This design incorporates a suction device. By observing the presence of the liquid column in the inlet pipe, the experimenter uses the suction device to extract gas from the Marvin flask. As the gas level decreases in the Marvin flask, the external atmospheric pressure pushes the liquid column in the inlet pipe back into the Marvin flask until it is completely inside. At this point, there is no liquid column in the inlet pipe, and the pressure at the bottom of the vertical tube equals standard atmospheric pressure. The liquid level in the test cylinder is also at standard atmospheric pressure, so there is no pressure difference, preventing "pressurized water intake." This allows for more accurate control of the water replenishment amount and reduces experimental error. Attached Figure Description

[0021] Figure 1 This is a liquid level diagram of an existing Marble bottle during the experiment;

[0022] Figure 2 This is a schematic diagram of the structure of the Marsh bottle in this design during the experiment;

[0023] Figure 3 This is a liquid level diagram of the Marble bottle used in this scheme during the experiment;

[0024] Figure 4 These are the ideal water replenishment curves without pressure, the water replenishment curves for this solution, and the water replenishment curves when there is a liquid column in the air intake pipe.

[0025] Reference numerals: 1. Mascherano bottle body; 2. Inlet pipe; 21. Vertical pipe; 22. Horizontal pipe; 3. Inlet pipe valve; 4. Water inlet; 5. Bottle stopper; 6. Water outlet; 7. Water outlet pipe; 8. Suction port; 9. Suction pipe; 10. Piston; 11. Suction rod; 12. T-connector; 13. First check valve; 14. First outlet pipe; 15. Second check valve; 16. Second outlet pipe; 17. External pipe valve. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1:

[0027] See Figure 2 A pressure-regulating Marvi bottle instrument includes a Marvi bottle body 1, with its axis arranged vertically. An air inlet pipe 2 is fixedly connected to the peripheral wall of the Marvi bottle body 1. The air inlet pipe 2 includes a vertical pipe 21 and a horizontal pipe 22, which are fixedly connected and communicate with each other. The axis of the vertical pipe 21 is parallel to the axis of the Marvi bottle body 1 and is located within the Marvi bottle body 1. The axis of the horizontal pipe 22 is arranged radially along the Marvi bottle body 1. One end of the horizontal pipe 22 extends into the Marvi bottle body 1 and is connected and communicates with the vertical pipe 21; the other end of the horizontal pipe 22 extends out of the Marvi bottle body 1. The height of the horizontal pipe 22 is higher than the lower end of the vertical pipe 21, so the upper end of the horizontal pipe 22 is fixedly connected to the vertical pipe 21. An air inlet valve 3 is fixed on the horizontal pipe 22, located on the outside of the Marvi bottle body 1, for the user to open or close the air inlet pipe 2.

[0028] The top of the Marshall flask body 1 has a water inlet 4, and a stopper 5 is inserted at the water inlet 4 to open or close the water inlet 4. The lower end of the Marshall flask body 1 has a water outlet 6, which is connected to one side of the periphery of the Marshall flask body 1. The height of the water outlet 6 is lower than the lower end of the vertical pipe 21. The water outlet 6 is connected to the test cylinder via a water outlet pipe 7. An external connecting valve 17 for opening and closing the water outlet pipe 7 is fixed on the water outlet pipe 7.

[0029] The top surface of the Marshall bottle body 1 is provided with an air extraction port 8. An air extraction device is fixedly connected to the Marshall bottle body 1, and the air extraction device is connected to the cavity of the Marshall bottle body 1 through the air extraction port 8.

[0030] The air extraction device in this embodiment includes:

[0031] A suction pipe 9 is provided, and a piston 10 is installed in the suction pipe 9. The piston 10 is sealed to the inner wall of the suction pipe 9 and can move along the axis of the suction pipe 9. A suction rod 11 is fixedly connected to the piston 10. The end of the suction rod 11 away from the piston 10 extends out of the suction pipe 9 from the end corresponding to the axis of the suction pipe 9. The suction rod 11 can move along the axis of the suction pipe 9 and push the piston 10 to move. A three-way pipe 12 is provided at the end of the suction pipe 9 away from the suction rod 11, and the suction pipe 9 and the A end of the three-way pipe 12 are fixedly connected and communicate with each other.

[0032] The first one-way valve 13 has one end fixedly connected to and communicates with the B end of the three-way pipe 12, and the other end of the first one-way valve 13 is fixedly connected to the first vent pipe 14. The first one-way valve 13 communicates with the cavity of the Marshall bottle body 1 through the first vent pipe 14 and the suction port 8. The first one-way valve 13 is only in the open state when the air pressure in the first vent pipe 14 is greater than the air pressure in the three-way pipe 12; otherwise, the first one-way valve 13 is in the closed state.

[0033] The second one-way valve 15 has one end fixedly connected to and in communication with end C of the three-way pipe 12, and the other end fixedly connected to a second vent pipe 16, which connects the second one-way valve 15 to the outside atmosphere. The second one-way valve 15 is only open when the air pressure in the three-way pipe 12 is greater than the outside atmospheric pressure; otherwise, it is closed. In other embodiments, a vacuum pump or other mechanical device can be used as the pumping device. Example 2:

[0034] A method for operating a Marshall bottle includes the following steps:

[0035] S1: Ensure the sealing of all connections in the Marshall bottle body 1. When the liquid level in the Marshall bottle body 1 is about to fall below the lower end of the vertical pipe 21, the water level in the Marshall bottle body 1 is insufficient, and preparations are made to start supplying water to the Marshall bottle body 1.

[0036] S2: Close the air inlet valve 3 and the external pipe valve 17; remove the bottle stopper 5 at the water inlet 4 (see...). Figure 2 Water is injected into the body of the Marshall flask 1 through the water inlet 4. When injecting water, the liquid level should not completely seal the water inlet, leaving an opening for gas to escape from the body of the Marshall flask 1. The preferred water injection height is: the liquid level in the body of the Marshall flask 1 is higher than the air inlet pipe 2, but the body of the Marshall flask 1 should not be completely filled with water, leaving a gap. Because the body of the Marshall flask is transparent, the liquid level can be easily observed.

[0037] S3: Plug the bottle stopper 5 into the water inlet 4 to seal the water inlet 4; open the air inlet valve 3 and keep the external pipe valve 17 closed; under the pressure of the water head inside the Marshall bottle 1, the end of the horizontal pipe 22 leaks a little water and then stops leaking. The amount of leakage is negligible and does not affect the test of this device.

[0038] S4: Since the liquid level in the Marble bottle body 1 is higher than the height of the inlet pipe 2, there must be a liquid column in the inlet pipe 2; by continuously pulling the suction rod 11, the piston 10 reciprocates along the axis of the suction pipe 9; when the piston 10 moves upward, the gas pressure in the three-way pipe 12 decreases, and the gas pressure in the Marble bottle body 1 is greater than the gas pressure in the three-way pipe 12. The gas in the Marble bottle body 1 compresses the spring of the first one-way valve 13, the first one-way valve 13 opens, and the gas in the Marble bottle body 1 enters the three-way pipe 12 through the first outlet pipe 14; when the piston 10 moves downward... At this time, the air pressure in the three-way pipe 12 increases, and the air pressure in the three-way pipe 12 is greater than the external air pressure. The gas in the three-way pipe 12 compresses the spring of the second one-way valve 15, and the second one-way valve 15 opens. The gas in the three-way pipe 12 flows into the atmosphere through the second outlet pipe 16. In this way, the gas in the Marvin bottle body 1 is continuously drawn into the atmosphere. At this time, the air pressure in the Marvin bottle body 1 is less than the atmospheric pressure. The atmospheric pressure will push the liquid column in the inlet pipe 2 to move, and the liquid column in the inlet pipe 2 will gradually enter the Marvin bottle body 1.

[0039] S5: When the liquid column in the inlet pipe 2 has just completely entered the Martens bottle body 1 ( Figure 3 (State), stop pumping; at this time, formulas (1) and (2) are satisfied.

[0040] P1=ρgh+P0= P A (1)

[0041] P2= P1= P A (2)

[0042] Where P0 is the gas pressure at the free liquid surface inside the Marble flask (Pa), P1 is the pressure at the bottom of the vertical tube (Pa), and P2 is the gas pressure at the free liquid surface inside the test tube (Pa). A ρ is the standard atmospheric pressure (Pa); g is the gravitational acceleration; h is the distance (m) from the free surface of the Marshall bottle to the bottom of the vertical tube.

[0043] S6: Keep the air inlet valve 3 open, open the external pipe valve, and supply water to the test tube by the liquid level in the Marshall bottle; when the liquid level in the test tube is lower than the lower end of the vertical pipe 21, the liquid level in the Marshall bottle flows into the test tube, keeping the liquid level in the test tube always equal to the height of the lower end of the vertical pipe.

[0044] Comparative example:

[0045] For the unidirectional freezing test of soil, the relationship between water replenishment and time under different working conditions was tested and recorded as follows: Figure 4 As shown; among them, normal pressureless water replenishment means that the pressure on both sides is atmospheric pressure (i.e., there is no liquid column in the air inlet tube of the Marsh bottle), the water-replenishing end can freely draw water, while the water level at the replenishing end remains unchanged.

[0046] It is easy to see that in the early stage of the experiment, the difference in water replenishment in the three cases is almost negligible. Within 10 to 200 hours of the experiment, the water replenishment in the existing air inlet pipe with liquid column is greater than the water replenishment in the air inlet pipe without liquid column in this scheme. This is because there is liquid column in the air inlet pipe, and the pressure generated by the liquid column in the air inlet pipe produces additional water replenishment for the test tube.

[0047] Finally, after 200 hours, the difference between the water replenishment amounts gradually decreased and showed a tendency to intersect. This is because as water is consumed during the replenishment process, the liquid level in the intake pipe also drops, resulting in a decrease in the water head in the intake pipe until it disappears. The pressure difference between the bottom of the intake pipe and the water replenishment end also decreases, and the two curves tend to overlap.

[0048] Therefore, it can be seen that, objectively speaking, this scheme does make the water replenishment volume more consistent with the situation of unpressurized water replenishment. That is, the water replenishment volume of this scheme is more accurate, the error of the experiment is smaller, and the experimental results are more accurate.

[0049] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A pressure-regulating Marvin bottle instrument, comprising a Marvin bottle body, an air inlet pipe fixed to the Marvin bottle body, one end of the air inlet pipe extending into the cavity of the Marvin bottle body, and the other end of the air inlet pipe extending out of the Marvin bottle body; characterized in that, An air inlet valve for opening and closing the air inlet is fixed on the air inlet pipe; a water inlet communicating with the cavity of the Marshall bottle is provided on the Marshall bottle body, and a bottle stopper for sealing the water inlet is provided on the Marshall bottle body. The Marshall flask has an air extraction port located above the air inlet pipe. An air extraction device is connected to the Marshall flask, and the device communicates with the cavity of the flask through the air extraction port. The Marshall flask also has a water outlet, and a water outlet pipe is connected to it. One end of the water outlet pipe is connected to the water outlet, and the other end is connected to the test cylinder. An external valve for opening and closing the water outlet pipe is fixedly connected to the water outlet pipe.

2. The Martens bottle instrument with adjustable pressure and vacuum capability according to claim 1, characterized in that, The air inlet pipe includes a vertical pipe and a horizontal pipe. The vertical pipe is located in the cavity of the Marshall bottle body. One end of the horizontal pipe is connected to and communicates with the upper end of the vertical pipe, and the other end of the horizontal pipe extends out of the cavity of the Marshall bottle body from the side wall of the Marshall bottle body.

3. The Martens bottle instrument with adjustable pressure and vacuum capability according to claim 2, characterized in that, The air inlet valve is fixed on the horizontal tube and is located outside the cavity of the Martens bottle body.

4. The Martens bottle instrument with adjustable pressure and vacuum capability according to claim 2, characterized in that, The water inlet is located above the air inlet pipe.

5. A method for operating a Marlboro bottle instrument, used in any one of claims 2-4 for a Marlboro bottle instrument with adjustable pressure and vacuum, characterized in that, Includes the following steps: S1: Observe the liquid level in the Marshall bottle. When the liquid level is lower than the bottom of the vertical pipe, prepare to supply water to the Marshall bottle. S2: Close the air inlet valve and the external pipe valve; remove the bottle stopper at the water inlet; fill the Marshall bottle with water through the water inlet, so that the liquid level in the Marshall bottle is higher than the lower end of the vertical pipe, and the liquid level in the Marshall bottle does not fill the cavity of the Marshall bottle. S3: Plug the bottle cap into the water inlet; open the air inlet valve, and keep the external pipe valve closed; S4: Use a vacuum device to extract the gas from the body of the Marvin flask, and the liquid column in the inlet pipe continuously flows into the body of the Marvin flask. S5: Stop pumping air when the liquid column in the inlet pipe has just completely entered the Marshall bottle; S6: Keep the intake pipe valve open and open the external pipe valve.

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