A device for measuring the rate of soil denitrification

Abstract

The utility model discloses a kind of soil denitrification rate determination devices, including test box, top cover, trachea, three-way valve and balloon;The test box top surface is open to put into soil column sample in the test box;The top cover is detachably connected in the top surface of the test box to cover the opening;The number of trachea is multiple, and one end of multiple trachea penetrates the top cover and extends into the inner chamber of the test box, and the other end is located outside the test box;Wherein one end of one trachea away from the test box is fixed with the three-way valve, and the other end corresponding to it is fixed with the balloon in the test box.The utility model is communicated with outside atmosphere by setting balloon on top cover, in the process of air extraction operation to determination tank, utilize balloon to balance the negative pressure environment in determination tank, avoid the adverse effect caused by negative pressure to air in soil column and determination device, guarantee the sealing performance of determination device.

Description

Technical Field

[0001] This utility model relates to the field of soil monitoring technology, and more specifically to a soil denitrification rate measuring device. Background Technology

[0002] Soil denitrification refers to the process by which nitrates or nitrites in the soil are reduced to nitrogen (N2), nitrous oxide (N2O), or other nitrogen oxides by denitrifying bacteria under anaerobic conditions.

[0003] Soil denitrification rate is often determined using the acetylene inhibition-soil column culture method. Specifically, collected soil columns are placed in testing devices A and B, respectively. Device A is left untreated and serves as a control. For device B, a syringe with a three-way valve is connected to the three-way valve on the device, and 10% of the headspace air is extracted. Then, an equal volume of clean acetylene gas is injected into the device using the syringe. However, extracting 10% of the headspace air creates a negative pressure in the device. This negative pressure can passively draw air out of the soil column and may also cause deformation of the device, leading to leakage. Both of these factors can affect the accuracy of the soil denitrification rate measurement results.

[0004] Therefore, how to provide a soil denitrification rate measuring device that avoids the decrease in sealing performance caused by negative pressure is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] In view of this, the present invention provides a soil denitrification rate measuring device, which aims to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A soil denitrification rate measuring device includes a test chamber, a top cover, an air tube, a three-way valve, and a balloon;

[0008] The test chamber has an open top surface to allow a soil column sample to be placed inside; the top cover is detachably connected to the top surface of the test chamber to close the open surface.

[0009] There are multiple air tubes, one end of which passes through the top cover and extends into the inner cavity of the test chamber, while the other end is located outside the test chamber; one end of one air tube away from the test chamber is fixed with the three-way valve, and the other end of the corresponding air tube located inside the test chamber is fixed with the balloon.

[0010] The beneficial effects of this utility model are as follows: After placing the soil column in the test chamber and closing the top cover, 10% of the air above the soil column is extracted through a three-way valve. Then, an equal volume of acetylene gas is injected into the test chamber through the three-way valve. Acetylene inhibits the further reduction of N2O to N2, thus allowing N2O to accumulate. The total denitrification rate is calculated by measuring the N2O concentration. During the air extraction process, a negative pressure environment is created inside the test chamber. A balloon is connected via a tubing. When the test chamber is under negative pressure, the pressure difference causes external air to enter the balloon through the tubing, inflating it and increasing the gas volume inside the test chamber. As the balloon inflates, the pressure inside the test chamber gradually increases, reducing the negative pressure difference. This prevents deformation and air leakage between the test chamber and the top cover due to the negative pressure environment, or prevents the air in the soil column from being passively extracted, ensuring the overall sealing performance between the test chamber and the top cover, and ensuring the effective and smooth conduct of the measurement.

[0011] Preferably, the device also includes a waterproof connector, which is fixed to the top cover, and one end of the air tube passes through the waterproof connector. The air tube passes through both sides of the top cover and is secured by the waterproof connector. The sealing ring inside the waterproof connector ensures the sealing performance between the air tube and the top cover, while preventing moisture and dust from entering the measuring chamber and ensuring the accuracy of the measurement results.

[0012] Preferably, the air tube and the balloon are connected via a pneumatic connector. The pneumatic connector connects the balloon and the air tube, ensuring that outside air can pass through the air tube to inflate the balloon when a negative pressure environment is created inside the testing chamber. The balloon's expansion then balances the negative pressure environment inside the testing chamber.

[0013] Preferably, the top cover is circumferentially hinged with multiple snap-fit ​​fasteners, which can be fastened to the upper outer wall of the test chamber. The top cover is detachably connected to the test chamber via snap-fit ​​fasteners, facilitating the placement and removal of the soil column inside the test chamber.

[0014] Preferably, a sealing ring is embedded between the bottom surface of the top cover and the upper surface of the test chamber. The sealing ring ensures the sealing performance between the test chamber and the top cover.

[0015] Preferably, the air tube is a Teflon tube; there are two air tubes, one of which has the three-way valve fixed at one end outside the test chamber, and the other air tube has the balloon fixed at one end inside the test chamber.

[0016] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a soil denitrification rate measuring device. By setting a balloon on the top cover that is connected to the outside atmosphere, the balloon is used to balance the negative pressure environment inside the measuring chamber during the air extraction operation, so as to avoid the adverse effects of negative pressure on the air in the soil column and the measuring device, and to ensure the sealing performance of the measuring device. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 A schematic diagram of the measuring device provided by this utility model;

[0019] Figure 2 This is a schematic diagram of the internal structure of the measuring device provided by this utility model.

[0020] Among them, 1-test box; 2-top cover; 3-waterproof connector; 4-air pipe; 5-three-way valve; 6-bucket; 7-balloon; 8-pneumatic connector; 9-sealing ring. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] like Figure 1 and 2 As shown in the figure, this utility model embodiment discloses a soil denitrification rate measuring device, including a test box 1, a top cover 2, an air pipe 4, a three-way valve 5, and a balloon 7; the balloon 7 balances the negative pressure environment inside the measuring device to prevent the air in the soil column from being passively extracted, the measuring device from deforming, and air leakage caused by the negative pressure.

[0023] The test chamber 1 has an open top surface to allow a soil column sample to be placed inside. A detachable top cover 2 is attached to the top surface of the test chamber 1 to close the open surface. After the top cover 2 closes the open surface of the test chamber 1, a sealed testing device is formed. Multiple air tubes 4 are present, with one end penetrating the top cover 2 and extending into the inner cavity of the test chamber 1, and the other end located outside the test chamber 1. A three-way valve 5 is fixed to the end of one air tube 4 furthest from the test chamber 1, and a balloon 7 is fixed to the corresponding end of the other air tube 4 inside the test chamber 1. Preferably, there are two air tubes 4, with the three-way valve 5 fixed to the end of one air tube 4 outside the test chamber 1, and a balloon 7 fixed to the end of the other air tube 4 inside the test chamber 1.

[0024] Two sets of measuring devices were used as control experiments during the measurement process. One set was placed in a soil column without any treatment, while the other set was placed in a soil column and then air was evacuated from the measuring chamber using a syringe and a three-way valve. The amount of air evacuated was approximately 10% of the air volume in the measuring chamber. After the air was evacuated, a negative pressure environment was created in the measuring chamber. Under the action of the pressure difference between the inside and outside, outside air entered the balloon through another air tube, causing the balloon to inflate. The balloon's expansion increased the air volume in the measuring chamber, thus achieving the effect of balancing the negative pressure. After the air in the measuring chamber was evacuated, acetylene gas of the same volume as the evacuated air was injected into the measuring chamber through the three-way valve. Acetylene inhibits the further reduction of N2O to N2, thereby causing N2O to accumulate. The total denitrification rate was calculated by measuring the N2O concentration.

[0025] In this embodiment, the gas tube is a Teflon tube with a diameter of 4 mm. The Teflon tube is mainly made of polytetrafluoroethylene (PTFE), which has the advantages of corrosion resistance, insulation, aging resistance and low friction coefficient, and meets the requirements of the acetylene inhibition method for determining the soil denitrification rate.

[0026] To further optimize the above technical solution and ensure the sealing performance between the top cover and the air pipe, a waterproof connector 3 is also included. The waterproof connector 3 is fixed on the top cover 2, and one end of the air pipe 4 passes through the waterproof connector 3.

[0027] The waterproof connector uses the PG7 model. There are two round holes on the top cover. The two waterproof connectors are inserted into the two round holes one by one. The air tube passes through the waterproof connector and is tightened. The sealing ring of the waterproof connector ensures the air tube and the top cover are sealed.

[0028] To further optimize the above technical solution, the air tube 4 and the balloon 7 are connected via a pneumatic connector 8.

[0029] The pneumatic connector is model PG 8-4 or PG 6-4. It connects the air tube to the balloon and has good airtightness, ensuring an effective connection between the balloon and the air tube while also ensuring a tight seal to prevent air leakage.

[0030] In some other embodiments, the top cover 2 is circumferentially hinged with a plurality of snap fasteners 6, which can be snapped and fastened to the upper outer wall of the test chamber 1.

[0031] To further optimize the above technical solution and improve the sealing between the top cover and the test chamber, a sealing ring 9 is embedded between the bottom surface of the top cover 2 and the upper surface of the test chamber 1.

[0032] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0033] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A soil denitrification rate measuring device, characterized in that, Includes a test box (1), a top cover (2), an air tube (4), a three-way valve (5), and a balloon (7); The test chamber (1) has an open top surface to allow a soil column sample to be placed inside; the top cover (2) is detachably connected to the top surface of the test chamber (1) to close the open surface. There are multiple air tubes (4). One end of each air tube (4) passes through the top cover (2) and extends into the inner cavity of the test box (1), while the other end is located outside the test box (1). One end of one air tube (4) away from the test box (1) is fixed with the three-way valve (5), and the other end of the corresponding air tube (4) inside the test box (1) is fixed with the balloon (7).

2. The soil denitrification rate measuring device according to claim 1, characterized in that, It also includes a waterproof connector (3), which is fixed on the top cover (2), and one end of the air pipe (4) passes through the waterproof connector (3).

3. The soil denitrification rate measuring device according to claim 1, characterized in that, The air tube (4) is connected to the balloon (7) via a pneumatic connector (8).

4. The soil denitrification rate measuring device according to claim 1, characterized in that, The top cover (2) is circumferentially hinged with multiple buckles (6), which can be fastened to the upper outer wall of the test box (1).

5. The soil denitrification rate measuring device according to claim 4, characterized in that, A sealing ring (9) is embedded between the bottom surface of the top cover (2) and the upper surface of the test box (1).

6. A soil denitrification rate measuring device according to any one of claims 1 to 5, characterized in that, The air tube (4) is a Teflon tube; there are two air tubes (4), one of which is fixed with the three-way valve (5) at one end outside the test box (1), and the other air tube (4) is fixed with the balloon (7) at one end inside the test box (1).

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