RU169373U1 - Automatic chamber for measuring greenhouse gas flows at the soil-atmosphere interface - Google Patents

Abstract

The utility model relates to the field of ecology, in particular, to methods for measuring greenhouse gas emissions from soil and plants using sampling chambers. The proposed automatic camera for measuring greenhouse gas flows on the soil-atmosphere interface is made of two parts: a movable and a fixed part, and contains a square base for mounting the camera on the ground, while the fixed part of the camera is made in the form of a square frame, mounted on a solid sheet of transparent material mounted on vertical posts fixed on the base, and the movable part of the chamber is formed by a frame having the shape of a rectangular parallelepiped with with a vadra base on which the side walls of transparent material are installed, it additionally contains a cross-shaped frame mounted above the frame, the forming elements of which are fixed to the corners of the frame, and the rods of pneumatic cylinders mounted vertically on the base of the camera are attached to the ends of the frame elements the upper parts of the pneumatic cylinder housings are mounted on an additional square-shaped frame parallel to the base of the chamber. The technical result is: increasing the reliability of the measurement of greenhouse gas flows obtained by ensuring reliable tightness of the chamber in the closed position and the absence of elements of pneumatic drives inside the working volume of the chamber; continuous measurements in automatic mode; increasing the reliability of the design of the camera with increased wind load; reduced recovery time

Description

The technical field to which the utility model relates.

The utility model relates to the field of ecology, in particular, to methods for measuring greenhouse gas emissions from soil and plants using sampling chambers.

State of the art

The automatic camera known in Fig. 16 and described on pages 73-75 in the thesis is known [N. Shnyrev, Regime observations and gas exchange assessment at the border of the soil and the atmosphere (using the example of methane flows from the marsh hospital in the middle taiga zone of Western Siberia “Mukhrino”) . The dissertation for the degree of candidate of biological sciences. http://soil.msu.ru/attachments/article/2284/shnyrev_dissertation.pdf.].

The rectangular-shaped chamber is made of transparent material and has a base for mounting the chamber on the ground and with shutters installed in the upper part of the chamber, which are closed for the duration of the measurement. Initially, the flaps of the chamber are raised, it is open, and gas exchange with the atmosphere occurs freely, as it should be in natural conditions. The camera control unit contains an electric motor control circuit for raising and lowering the camera flaps. Fans for uniform mixing of air inside the chamber during the measurement period are mounted on a rail connecting the upper edges of the two side walls and serving as a supporting element for the lowering shutters of the chamber.

In the proposed version of the chamber, the quality of the tightness of the closure of the chamber can be called into question. According to illustrative materials, the tightness is ensured by the dead weight of the doors during the closed state of the chamber. The disadvantages of the camera include the reduced wind stability of the camera doors in the open position, which can lead to their mechanical deformation. Also, with this design, it would be more appropriate to place the fans on the doors in order to accelerate the ventilation of the internal volume of the chamber in the mode of its open state.

The automatic camera described in [Tree Physiology 23, 825-832, 2003 Heron Publishing-Victoria, Canada A multichannel automated chamber system for continuous measurement of forest soil CO2 efflux http: //research.eeescience.utoledo. edu / lees / papers_PDF / Liang_2003_TreePhys.pdf]

The camera has a rectangular shape and is made of a transparent material and the basis for installing the camera on the ground and the shutters installed in the upper part of the camera, which are closed for the duration of the measurement. The chamber is rectangular in shape with side walls made of transparent PVC material and glued to the frame (base) of extruded PVC for mounting the camera on the ground. The camera has covers, also made of PVC, mounted on hinges on the side walls. The edges of the covers are reinforced with a PVC strip, and a polyurethane rubber gasket is attached to the underside of the cover, on the inside of the PVC tape, to provide a tight seal with the chamber wall and the PVC strip glued to the center of the chamber at the junction of the covers. Each cover is connected to a piston of pneumatic cylinders located inside the chamber. The flaps are raised vertically or closed by pistons, which are controlled by compressed air from the compressor. Two fans are installed inside the chamber and provide air circulation when the chamber is closed and ventilation of the working volume of the chamber in the open position.

The operation (full-scale experiments) of a static camera designed by the authors of the above article revealed significant design flaws. These, first of all, include the arrangement of elements of pneumatic drives inside the chamber. During long-term operation, it was revealed that due to wear of the oil seals and aging of the sealing elements of the pneumatic cylinders (drives) of opening and closing the chamber doors, an unknown concentration is added due to leaks of the air mixture into the chamber’s internal volume, leading to distortion of the measurement of greenhouse gas flows. Also, the disadvantages include low wind resistance of the chamber doors and a sufficiently long ventilation time of the working volume of the chamber.

Utility Model Disclosure

The utility model is based on the task of developing the design of an automatic chamber for measuring greenhouse gas flows from the soil surface with an increased wind load and implementing quick ventilation of the working volume.

The technical result achieved in solving this problem is: to increase the reliability of measuring greenhouse gas flows obtained by ensuring reliable tightness of the chamber in the closed position and the absence of elements of pneumatic drives inside the working volume of the chamber; continuous measurements in automatic mode; increasing the reliability of the design of the camera with increased wind load; reduction of the time of restoration of natural atmospheric conditions in the measuring volume of the chamber.

The problem is solved in that the proposed automatic camera for measuring greenhouse gas flows on the soil-atmosphere interface is made of two parts: a movable and a fixed part, and contains a square base for mounting the camera on the ground, while the fixed part of the camera is made in a square-shaped frame with a solid sheet of transparent material fixed on it, mounted on vertical posts fixed on the base, and the movable part of the chamber is formed by a frame having the shape of a rectangular parallelepiped with a square base on which side walls are made of transparent material, while it additionally contains a cross-shaped frame mounted above the frame, the forming elements of which are fixed at the corners of the frame, and the rods of pneumatic cylinders mounted vertically on the base are attached to the ends of the frame chamber, while the upper parts of the housings of the pneumatic cylinders are mounted on an additional square-shaped frame located parallel to the base of the chamber.

Pneumatic cylinders are designed to move (raise and lower) the moving part of the chamber relatively stationary.

In addition, the base of the chamber is a prefabricated frame consisting of four elements: the first element is a plate with a square cut at the corners of which pneumatic cylinders are mounted; the second element is made in the form of a square well, providing a deepening of the base of the chamber in the soil, which is attached to the first element (plate) with the help of connecting elements (third element) made of a steel corner, ensuring rigidity of the entire prefabricated structure of the base, and the fourth element consists of two horizontally placed steel plates intended for fastening on the basis of vertical posts of the fixed part of the chamber.

In addition, the camera contains vertical guides that ensure the frame of the movable part of the camera with the base and optionally the frame, thereby imparting wind stability to the whole structure,

In this case, the cruciform frame is rigidly connected to the frame of the moving part with the help of studs.

The invention is illustrated in graphic materials.

In FIG. 1 is a drawing of the inventive automatic camera in the open position.

In FIG. 2 shows a drawing of the inventive automatic camera in the closed position.

The proposed automatic camera (Fig. 1) contains:

- the base of the chamber, consisting of a plate 1 with a square cut (820 × 820 mm), an element 2 made in the form of a square well, providing a deepening of the base of the chamber into the soil, connecting elements 3 (preferably three, fixed (welded) on each face of the well with its external side) for attaching the element 2 to the plate 1, thereby ensuring rigidity of the entire precast base structure; and two horizontally placed steel plates 4, mounted on opposite sides of the well from the inside;

- the moving part of the chamber 5, having the shape of a rectangular parallelepiped with a square base, including a frame made of an aluminum corner, on which side walls are made of transparent material - whole pieces of sheet polymethylmethacrylate (plexiglass);

- pneumatic cylinders 6, the base (lower part) of which is fixed on the plate 1;

- a cross-shaped frame 7, articulated with the frame of the chamber 5 with the help of studs 8, thereby providing articulation of the movable part of the chamber 5 with pneumatic cylinders 6, which move the movable part of the chamber;

- the stationary part of the chamber 9, made in the form of a square frame with a solid sheet of polymethylmethacrylate (plexiglas) fixed on it, mounted on vertical posts 10 fixed on the plates 4.

The rigidity of the structure is ensured by fixing the upper part of the pneumatic cylinders 6 with the help of an additional frame 11, wind stability is achieved through the use of vertical guides 12, which ensure the coupling of the movable part of the chamber 5 with the plate 1 and the frame 11 using bushings 13 installed in the lower part of the frame 5.

The inventive automatic chamber is designed for continuous research of greenhouse gas flows at the soil-atmosphere interface. The base of the camera is a prefabricated frame consisting of four elements. The first element is a plate 1 with a square cutout (820 × 820 mm) made of steel, on which pneumatic pneumatic cylinders 6 (CAMOZZI 60M2L032A0500) are mounted at the corners, the purpose of which is to ensure that the chamber is sealed against the base. The second base element is made in the form of a square well 2 and provides a deepening of the base of the chamber into the soil and is attached to the plate 1 with the help of connecting elements 3, ensuring rigidity of the entire precast construction of the base of the chamber. Butt joints of elements 1 and 2 are sealed. The fourth element consists of two horizontally placed steel plates 4, designed for fastening the uprights 10. On one of the sides of the square well 2 there are two fittings for connecting the air pipes (not shown) that supply the analyzed air to the gas analyzer and its return to the intracameral closed-loop space, as well as a sealed connector (not shown) for connecting an electrical cable that provides power to fans (not shown) , pressure and temperature sensors (not shown) and the transmission of the measured parameters to a computer. On the base plate 1, pneumatic cylinders 6 are vertically mounted, the upper parts of which are rigidly fixed to each other by means of an additional frame 11. The rods of pneumatic cylinders 6 are connected to the movable part of the chamber 5 by means of a cross-shaped frame 7 and studs 8. The movable part of the chamber 5 has the shape of a rectangular parallelepiped with square base. The frame is made of aluminum corner. The side walls are made of whole pieces of sheet polymethyl methacrylate (plexiglass). The pneumatic cylinders were selected so that the stroke of the rod in the ventilation mode of the measuring chamber ensured that its movable part 5 was raised above the level of the stationary 9. Vertical guides 12 exclude horizontal displacements of the movable part of the chamber 5 when it is in the “open” position, as well as during its upward movement or down. In the “closed” position, the base of the movable part of the chamber 5 is pressed firmly against the base plate 1, and the top is pressed firmly against the fixed part of the chamber 9. Sealing of the chamber in the closed state is ensured by W-shaped rubber seals attached to the lower part of the frame 5 mating with plate 1 and the upper part of the frame 5, mating with the fixed part of the chamber 9. All elements of pneumatic drives are located outside the working volume of the chamber.

Opening and closing of the proposed chamber is carried out by supplying compressed air to the pneumatic cylinders 6. To supply and distribute compressed air to the pneumatic cylinders 6, distributors (not shown) with electro-pneumatic control and spring return were selected. For simultaneous and uniform movement of 4 rods, raising and lowering the movable part of the chamber, pneumatic throttles with a check valve (not shown) were installed on the pneumatic cylinders 6.

The entire process of the camera is controlled and the measured parameters are recorded using a computer connected to the ADC and an array of transistor keys, according to the schedule of specially created software.

Claims (4)

1. The automatic chamber for measuring greenhouse gas flows on the soil-atmosphere interface is made of two parts: a movable and a fixed part, and contains a square base for mounting the camera on the ground, while the fixed part of the camera is made in the form of a square shape with a fixed on it a whole sheet of transparent material mounted on vertical posts fixed on the base, and the movable part of the camera is formed by a frame having the shape of a rectangular parallelepiped with a square o the base, on which the side walls of transparent material are installed, while it additionally contains a cross-shaped frame mounted above the frame, the forming elements of which are fixed to the corners of the frame, and the rods of pneumatic cylinders mounted vertically on the base of the camera are attached to the ends of the elements forming the frame parts of the pneumatic cylinder housings are mounted on an additional square-shaped frame located parallel to the base of the chamber. 2. The automatic chamber according to claim 1, characterized in that the base of the chamber is a prefabricated frame consisting of four elements: the first element is a plate with a square cutout, at the corners of which pneumatic cylinders are mounted; the second element is made in the form of a square well, providing a deepening of the base of the chamber into the soil, which is attached to the first element (plate) with the help of connecting elements (third element) made of steel corner, providing rigidity of the entire prefabricated base structure, and the fourth element consists of two horizontally placed steel plates intended for fastening on the basis of vertical posts of the fixed part of the chamber. 3. The automatic camera according to claim 1, characterized in that it further comprises vertical guides that allow the frame of the moving part of the camera to interface with the base and the additional frame. 4. The automatic chamber according to claim 1, characterized in that the cross-shaped frame is rigidly connected to the frame of the movable part by means of studs.

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