Foaming agent performance testing method and device

Abstract

The invention relates to the technical field of material property analysis, in particular to a foaming agent performance testing method and device.The foaming agent performance testing device comprises a main testing container used for containing a foaming agent solution and a testing particle container, and solid testing particles are contained in the testing particle container; the test particle container is provided with an outlet through which solid test particles pass to fall into the main test container, and the solid test particles are used for impacting the foaming agent solution in the main test container to generate foam, so that the phenomenon of liquid drop divergence in the falling process due to high-temperature and high-pressure conditions during testing is avoided, and effective impact on the foaming agent solution is ensured; the testing requirements are met, and testing under the condition of high temperature and pressure is adapted.

Description

Technical Field

[0001] The invention relates to the technical field of material property analysis, and in particular to a foaming agent performance testing method and device. Background Art

[0002] Foam drainage and gas production technology is widely used in gas fields to drain gas wells. Foam drainage and gas production technology is affected by the performance of foam drainage foaming agents. Therefore, studying the foaming properties of foaming agents is of great significance for the screening and application of foaming agents.

[0003] At present, the conventional method for testing the performance of foaming agents is to use a Roche foam meter to test under normal pressure conditions, where the foaming agent solution is free-falling and hits the liquid surface below to form foam, and the foam height or volume is measured to characterize the foaming performance of the foaming agent. However, this method for testing the performance of foaming agents does not simulate the high temperature and high pressure conditions in real formations, and its test results cannot intuitively reflect the foaming performance of the foaming agent under high temperature and high pressure conditions.

[0004] A Chinese utility model patent with authorization announcement number CN202869914U discloses a device for measuring the foaming ability and foam stabilizing ability of a foaming agent, which constitutes a foaming agent performance test device, including a jacketed insulation measuring cylinder, a separating funnel, and a gas cylinder. The jacketed insulation measuring cylinder constitutes a main test container. When in use, a certain amount of foaming agent solution is poured into the jacketed insulation measuring cylinder, and then a certain amount of foaming agent solution is poured into the separating funnel. The experimental gas is introduced into the jacketed insulation measuring cylinder using the gas cylinder. After opening the separating funnel, the foaming agent solution in the separating funnel falls into the jacketed insulation measuring cylinder. The internal foam volume is measured using the scale on the jacketed insulation measuring cylinder, and then the foaming ability is analyzed.

[0005] Although the above-mentioned foaming agent performance testing device can use a jacketed insulation measuring cylinder and a gas cylinder to perform tests at a certain temperature and pressure, this liquid impact method of foaming by using the free fall of the upper foaming agent solution to impact the lower foaming agent solution downward, when the temperature and pressure are high, due to the change in the surface properties of the foaming agent solution, the liquid droplets will diverge during the free fall process, and the further they go downward, the more they diverge. When the liquid droplets are close to the liquid surface of the foaming agent solution below, they will become very small, and it is difficult to form an effective impact on the liquid surface of the foaming agent solution below, so that no foam can be generated or too little foam is generated, and it cannot be adapted to the foaming performance test of the foaming agent under conditions of high temperature and pressure. Summary of the invention

[0006] The purpose of the present invention is to provide a foaming agent performance testing method to solve the problem that the current liquid impact method for foaming agent performance testing is not suitable for testing under conditions of high temperature and pressure; the purpose of the present invention is also to provide a foaming agent performance testing device to solve the above problem.

[0007] The technical solution of the foaming agent performance test method of the present invention is as follows:

[0008] A foaming agent performance test method includes allowing a certain number of solid test particles to fall into a foaming agent solution at a certain flow rate. The solid test particles impact the foaming agent solution to generate foam, and the generated foam is measured to evaluate the performance of the foaming agent.

[0009] Beneficial effects: The present invention uses solid test particles to impact the foaming agent solution to generate foam. Compared with the traditional droplet impact foaming method, there will be no phenomenon of droplet divergence during the falling process due to the high temperature and high pressure conditions during the test, ensuring an effective impact on the foaming agent solution, meeting the test requirements, and adapting to tests under higher temperature and pressure conditions.

[0010] The technical solution of the foaming agent performance test device of the present invention is as follows:

[0011] A foaming agent performance test device includes a main test container for containing a foaming agent solution, and also includes a test particle container. The test particle container contains solid test particles, and the test particle container has an outlet for the solid test particles to pass through and fall into the main test container. The solid test particles are used to impact the foaming agent solution in the main test container to generate foam.

[0012] Beneficial effects: The present invention uses the test particle container to contain solid test particles. The solid test particles can fall into the main test container after exiting from the outlet of the test particle container. Using the solid test particles to impact the foaming agent solution to generate foam, compared with the traditional droplet impact foaming method, there will be no phenomenon of droplet divergence during the falling process due to the high temperature and high pressure conditions during the test, ensuring an effective impact on the foaming agent solution, meeting the test requirements, and adapting to tests under higher temperature and pressure conditions.

[0013] Furthermore, the test particle container is arranged inside the main test container. The main test container is provided with an air injection port for injecting gas to increase the air pressure inside the main test container, and the test particle container is provided with a communication port communicating with the inner cavity of the main test container.

[0014] Beneficial effects: Arranging the test particle container inside the main test container and connecting the test particle container with the main test container can balance the air pressure between the test particle container and the main test container, which is beneficial to ensuring the smooth falling of the solid test particles. At the same time, this structure of connecting the test particle container inside the main test container is convenient for sealing and beneficial to simplifying the structure.

[0015] Furthermore, the main test container has a liquid addition port for adding the foaming agent solution. A plug cover is detachably installed at the liquid addition port, and the test particle container is installed on the plug cover.

[0016] Beneficial effects: When using a plug cover to install a test particle container, with the plug cover covering the liquid adding port, the test particle container is located inside the main test container, which facilitates the setting of the installation structure of the test particle container.

[0017] Furthermore, the test particle container is fixedly arranged inside the main test container, with the outlet facing downwards. A plugging member is movably arranged inside the test particle container, and the plugging member has an open position for opening the outlet and a plugging position for plugging the outlet during its movement stroke.

[0018] Beneficial effects: Fixing the test particle container inside the main test container and using the movably arranged plugging member to open and close the outlet is convenient for operation and helps to simplify the installation structure of the test particle container.

[0019] Furthermore, the plugging member includes a plugging portion and a magnetic attraction cooperation portion. The plugging portion is used to plug and open the outlet, and the magnetic attraction cooperation portion is used to cooperate with a magnet to drive the plugging member to move from the plugging position to the open position through magnetic attraction force.

[0020] Beneficial effects: Using a magnet to cooperate with the magnetic attraction cooperation portion of the plugging member to drive the plugging member to move from the plugging position to the open position through magnetic attraction force can make the plugging member and the test particle container completely inside the main test container, which is convenient for simplifying the sealing structure.

[0021] Furthermore, the plugging member is vertically movably arranged inside the test particle container, the magnetic attraction cooperation portion is arranged at the upper end of the plugging member, and the plug cover is vertically opposite to the magnetic attraction cooperation portion.

[0022] Beneficial effects: Making the magnetic attraction cooperation portion vertically opposite to the plug cover is convenient for using a magnet to approach the magnetic attraction cooperation portion at the plug cover, thereby driving the plugging member to move upwards, which is beneficial for reliable magnetic attraction.

[0023] Furthermore, the test particle container includes a main body portion and a straight pipe portion. The outer diameter of the main body portion is larger than that of the straight pipe portion, and the outlet is arranged at the straight pipe portion.

[0024] Beneficial effects: Using the straight pipe portion to restrict the flow direction of the solid test particles and guiding the solid test particles to fall vertically.

[0025] Furthermore, the caliber of the outlet is adapted to the particle size of the solid test particles.

[0026] Beneficial effects: Using the outlet to restrict the passage of the solid test particles, enabling the solid test particles to fall one by one in sequence, which is convenient for controlling the falling trajectory of the solid test particles.

[0027] Furthermore, the particle size of the solid test particles is 2 - 4 mm.

[0028] Beneficial effects: Such solid test particles can have a good impact effect when hitting the foaming agent solution, which is convenient for generating foam. Brief Description of the Drawings

[0029] Figure 1 Schematic structural diagram of the plugging member of the foaming agent performance testing device according to an embodiment of the present invention in the plugged position;

[0030] Figure 2 Schematic structural diagram of the plugging member of the foaming agent performance testing device according to an embodiment of the present invention in the open position.

[0031] In the figure: 1, main test container; 11, plugging cover; 12, viewing window; 2, test particle container; 21, main body part; 22, straight pipe part; 3, solid test particles; 4, plugging member; 5, magnet; 6, jacket; 61, water inlet; 62, water outlet; 7, gas injection pipe; 71, pressure gauge; 8, discharge valve; 9, temperature measurement interface; 10, bracket; 100, foaming agent solution; 101, foam. Detailed Embodiments

[0032] The present invention uses solid test particles to impact the foaming agent solution to generate foam. Compared with the traditional droplet impact foaming method, it will not show the phenomenon of droplet divergence during the falling process due to the high temperature and high pressure conditions during the test, ensuring an effective impact on the foaming agent solution, meeting the test requirements, and adapting to the test under higher temperature and pressure conditions.

[0033] Embodiment of the foaming agent performance testing device of the present invention:

[0034] As Figure 1 and Figure 2 shown, the foaming agent performance testing device includes a main test container 1 for containing the foaming agent solution 100 and a test particle container 2. The test particle container 2 contains solid test particles 3. The solid test particles 3 are ball beads, and there is a certain number of solid test particles 3 and they occupy a certain volume in the test particle container 2. The test particle container 2 has an outlet for the solid test particles 3 to pass through and fall into the main test container 1. The solid test particles 3 are used to impact the foaming agent solution 100 in the main test container 1 to generate foam 101.

[0035] The main test container 1 includes a container main body and a plugging cover 11. The container main body is a cylindrical structure with the cylinder mouth facing upwards. The upper cylinder mouth of the container main body forms a liquid adding port for adding the foaming agent solution 100 into the container main body. A plugging cover 11 is detachably installed at the liquid adding port, and the plugging cover 11 is sealed and installed at the upper end of the container main body. A viewing window 12 is provided on the container main body of the main test container 1. The viewing window 12 is formed by glass and is used to observe the situation inside the main test container 1. The glass is provided with scales for measuring the height of the foam 101. The plugging cover 11 of the main test container 1 and the part of the container main body other than the viewing window 12 are made of metal materials. The glass is hermetically combined with the metal part, and the main test container 1 is a closed pressure-resistant container.

[0036] The test particle container 2 is arranged inside the main test container 1 and the test particle container 2 is installed under the plug cover 11. To show the structure of the test particle container 2, the part above the dotted line in the figure is a schematic diagram of the internal structure of the main test container 1, and the part below the dotted line is a schematic diagram of the external structure of the main test container 1. The test particle container 2 includes a main body part 21 and a straight pipe part 22. The main body part 21 is a cylinder with the cylinder opening facing upwards. The main body part 21 and the straight pipe part 22 are coaxially arranged up and down. The straight pipe part 22 is connected to the bottom of the main body part 21, and the outer diameter of the straight pipe part 22 is smaller than the outer diameter of the main body part 21. An external thread is provided at the upper end of the main body part 21, and a threaded connection sleeve is provided at the bottom of the plug cover 11. The threaded connection sleeve is provided with an internal thread to fixedly connect the test particle container 2 with the plug cover 11. By using the plug cover 11 to install the test particle container 2, when the plug cover 11 is covered at the liquid adding port, the test particle container 2 is located inside the main test container 1, which is convenient for the installation operation of the test particle container 2.

[0037] The inner cavity of the main body part 21 is used to hold the solid test particles 3. The downward orifice of the inner hole of the straight pipe part 22 is used to form an outlet for the solid test particles 3 to fall out of the test particle container 2, and the outlet is arranged downwards. A blocking member 4 is movably arranged inside the test particle container 2. The blocking member 4 has an open position for opening the outlet and a blocking position for blocking the outlet during its movement stroke. When the blocking member 4 is in the blocking position, it blocks the communication part between the bottom of the main body part 21 and the upper part of the straight pipe part 22, blocking the straight pipe part 22 and thus blocking the outlet. The bottom of the main body part 21 is hemispherical or conical, and the straight pipe part 22 is connected to the center of the bottom of the main body part 21, which is convenient for the ball beads to flow into the straight pipe part 22 when the blocking member 4 is in the open position. The straight pipe part 22 is used to restrict the flow direction of the solid test particles 3 and guide the solid test particles 3 to fall vertically.

[0038] An air injection port for injecting gas to increase the air pressure inside the main test container 1 is provided at the upper part of the container body of the main test container 1. The air injection port is connected with an air injection pipe 7, and a pressure gauge 71 is provided on the air injection pipe 7. The pressure gauge 71 can measure the pressure inside the main test container 1. A plurality of communication holes are provided on the outer peripheral surface of the upper part of the test particle container 2. The communication holes form a communication port for communicating the test particle container 2 with the inner cavity of the main test container 1, which is used to balance the pressure difference inside and outside the test particle container 2, facilitating the smooth falling of the solid test particles 3. At the same time, this structure of communicating the test particle container 2 inside the main test container 1 does not require a bypass pipeline for balancing the air pressure between the test particle container 2 and the main test container 1 outside the container, which is convenient for sealing and helps to simplify the structure.

[0039] The plugging member 4 includes an upper disk body, a vertical rod body, and a lower disk body. The upper and lower ends of the vertical rod body are respectively connected to the upper disk body and the lower disk body. The upper disk body is a cylindrical disk, and the outer diameter of the upper disk body is slightly smaller than the inner diameter of the main body portion 21 of the test particle container 2. By matching the upper disk body with the inner wall of the cavity of the main body portion 21, the plugging member 4 can be kept moving up and down. The lower disk body is a conical disk with the conical surface facing upward. The lower disk body constitutes a plugging portion, and the plugging portion is used to plug and open the outlet. The upper disk body is provided with a particle through-hole that penetrates up and down. The solid test particles 3 can be loaded into the test particle container 2 through the particle through-hole. The solid test particles 3 are placed in the space below the upper disk body in the test particle container 2, and the straight pipe portion 22 is plugged by the lower disk body to keep the solid test particles 3 in the test particle container 2. The difference between the maximum outer diameter of the lower disk body and the inner diameter of the main body portion 21 is greater than the diameter of the solid test particles 3. When the plugging member 4 moves upward to open the outlet, the solid test particles 3 can fall smoothly, and the conical surface of the lower disk body of the plugging member 4 is used to prevent the solid test particles 3 from staying in the test particle container 2.

[0040] The upper disk body of the plugging member 4 constitutes a magnetic chuck, and the magnetic chuck constitutes a magnetic attraction cooperation portion. The plugging cover 11 is opposite to the magnetic attraction cooperation portion up and down. The magnetic attraction cooperation portion is used to cooperate with the magnet 5 to drive the plugging member 4 from the plugging position to the open position through magnetic attraction. The magnet 5 is a movable strong magnetic body. When placed on the plugging cover 11, it can suck up the plugging member 4 to open a ball dropping channel for the ball beads. The ball dropping channel is the inner hole of the straight pipe portion 22. Driving the plugging member 4 to move by magnetic attraction can make the plugging member 4 and the test particle container 2 completely located in the main test container 1, which is convenient for simplifying the sealing structure. The larger area of the disk surface of the magnetic chuck is convenient for cooperating with the magnet 5, which is beneficial to reliable magnetic attraction.

[0041] The aperture of the inner hole of the straight pipe portion 22 is the same as the caliber of the outlet, and the aperture of the inner hole of the straight pipe portion 22 is adapted to the particle size of the solid test particles 3. The passage of the solid test particles 3 is restricted by the outlet, so that the solid test particles 3 fall one by one in sequence, which is convenient for controlling the falling trajectory of the solid test particles 3.

[0042] The ball beads constituting the solid test particles 3 are spherical glass beads. The solid test particles 3 are insoluble in the foaming agent solution 100 and do not react with the foaming agent solution 100, and their size meets the foaming requirements. The particle size of the ball beads is 2.9 mm, and the inner diameter dimension of the container main body of the main test container 1 is 50 mm. In order to make the falling ball hit the central part of the liquid surface of the foaming agent solution 100, the straight pipe portion 22 is coaxially arranged with the container main body of the main test container 1.

[0043] The bottom of the container body of the main test container 1 is fixedly supported on the bracket 10, and the bracket 10 is used to leave an arrangement space for the discharge pipeline. The discharge pipeline is connected to the bottom of the container body of the main test container 1 and communicates with the inner cavity of the main test container 1. A discharge valve 8 is provided on the discharge pipeline. The discharge valve 8 is a ball valve, which is used to discharge the liquid and solid test particles 3 in the main test container 1 when it is opened. To enable the ball bead to pass smoothly, the inner diameter of the ball valve should be larger than the diameter of the ball bead. To better promote the flow of the ball bead and the liquid, the bottom surface of the inner cavity of the main test container 1 adopts a spherical structure or a conical structure.

[0044] A heating jacket 6 is provided outside the main test container 1. The jacket 6 includes a water inlet 61 and a water outlet 62 for circulating water to flow through and heat the main test container 1. A temperature measuring interface 9 is provided at the lower part of the main test container 1 to connect a temperature measuring component to measure the temperature of the liquid in the main test container 1. The temperature measuring component can adopt a temperature sensor.

[0045] During use, first close the ball valve, open the plug cover 11, and then slowly pour 200 mL of the prepared foaming agent solution with a concentration of 0.3% along the side wall of the container body of the main test container 1. Install the plugging member 4 into the test particle container 2. The plugging member 4 seals the straight pipe portion 22. Load the ball beads into the test particle container 2 through the through holes on the upper disc body of the plugging member 4, and then connect the test particle container 2 to the bottom of the plug cover 11. Install the plug cover 11 on the container body of the main test container 1 and tighten and seal it. The total volume of all the solid test particles 2 piled up together is about 200 mL. The outlet is 900 mm away from the liquid level. Start the external water circulation, let the hot water enter from the water inlet 61 and discharge from the water outlet 62 to heat the main test container 1 until the temperature sensor at the temperature measuring interface 9 feeds back that the test temperature is reached and the temperature is stable. Inject high-pressure nitrogen into the main test container 1 through the injection pipe 7, observe the pressure gauge 71, and make the pressure in the main test container 1 reach 8 Mpa. After reaching the test pressure, close the valve on the injection pipe 7. Place the magnet 5 on the plug cover 11, and the plugging member 4 moves upward under the action of magnetic suction, and the ball dropping channel is opened. The ball beads make a free fall along the straight pipe portion 22 and hit the liquid surface of the foaming agent solution 100 below to form foam 101. Wait until all the ball beads in the test particle container 2 have fallen. Observe the upper and lower scale lines of the foam 101 part through the viewing window 12 and record the scale difference of 120 mm, that is, the foam height. This scale difference characterizes the foaming performance of the foaming agent. After the test is completed, turn off the water circulation, open the valve on the injection pipe 7 and slowly exhaust to atmospheric pressure, and finally open the ball valve below the main test container 1 to discharge the ball beads and the foaming agent solution 100.

[0046] Through this foaming agent performance test device, using solid test particles as the medium for impact foaming, it can well adapt to the foaming performance test of foaming agents under high temperature and high pressure conditions.

[0047] In other embodiments, the test particle container can also be arranged outside the main test container, and a connecting pipe is provided between the main test container and the test particle container. The upper end of the connecting pipe is connected to the outlet of the test particle container, and the lower end passes through the plugging cover of the main test container and extends into the main test container. A valve is provided on the connecting pipe. When the valve is opened, the solid test particles in the main test container fall into the main test container through the connecting pipe. The test particle container is a closed container. In order to balance the air pressure in the test particle container and the main test container, a bypass pipe is also provided between the main test container and the test particle container. One end of the bypass pipe is connected to the inner cavity of the main test container, and the other end is connected to the space above the solid test particles in the test particle container.

[0048] In other embodiments, the test particle container can also be installed on the container body of the main test container. Specifically, a slot can be provided on the upper part of the container body of the main test container, and a connecting rod can be horizontally provided on the upper end of the test particle container. The connecting rod is inserted into the slot to enable the test particle container to be installed on the container body of the main test container.

[0049] In other embodiments, the test particle container can also be rotatably mounted on the plug cover, and the test particle container can be flipped over. The magnetic attraction of the magnet can drive the test particle container to flip over, so that the solid test particles are poured out from the mouth of the cylindrical test particle container. In this case, the test particle container may no longer be provided with an outlet.

[0050] In other implementations, the upper end of the blocking piece can also be passed through the blocking cover, and the blocking piece can be movably sealed at the passing portion of the blocking cover, and the part of the blocking piece passing through the blocking cover can be used to drive the blocking piece to move up and down. In this case, the magnet and the magnetic attraction matching part are no longer required.

[0051] In other embodiments, the blocking member can also be moved horizontally to open the outlet by increasing the inner diameter of the test particle container and making the blocking member have only a lower disk body, and then the blocking member can be moved horizontally by a magnet on one side of the main test container to be offset from the outlet, thereby opening the outlet.

[0052] In other implementations, the test particle container may not be provided with a straight tube portion, and the outlet is directly provided at the bottom of the main body.

[0053] In other embodiments, the diameter of the outlet may be more than twice the diameter of the solid test particles.

[0054] In other embodiments, the particle size of the solid test particles may also be 2 mm or 4 mm, or other values ​​within the range of 2-4 mm, or the particle size of the solid test particles may be 1 mm.

[0055] In other embodiments, the solid test particles may also be metal beads as long as they are insoluble in the foaming agent solution.

[0056] Example of the method for testing the performance of the foaming agent of the present invention:

[0057] The method for testing the performance of the foaming agent in this example is implemented by using the above-mentioned foaming agent performance testing device. The method for testing the performance of the foaming agent includes allowing a certain number of solid test particles to fall into the foaming agent solution at a certain flow rate. The solid test particles impact the foaming agent solution to generate foam, and the height of the generated foam is measured to evaluate the performance of the foaming agent. The flow rate of the solid test particles also represents the number of solid test particles passing through the outlet per unit time. Each solid test particle falls into the foaming agent solution in sequence, and the size of the solid test particles meets the requirement for generating foam by impacting the foaming agent solution.

[0058] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative efforts, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for testing the performance of a foaming agent, characterized in that, A certain number of solid test particles are dropped into the foaming agent solution at a certain flow rate. The solid test particles impact the foaming agent solution to generate foam, and the generated foam is measured to evaluate the performance of the foaming agent.

2. A foaming agent performance testing device, including a main testing container for containing a foaming agent solution, characterized in that, It further includes solid test particles and a test particle container for containing the solid test particles. The test particle container has an outlet through which the solid test particles pass and fall into the main test container. The solid test particles are used to impact the foaming agent solution in the main test container to generate foam.

3. The foaming agent performance testing device according to claim 2, characterized in that, The test particle container is arranged in the main test container. The main test container is provided with an air injection port for injecting gas to increase the air pressure in the main test container. The test particle container is provided with a communication port communicating with the inner cavity of the main test container.

4. The foaming agent performance testing device according to claim 3, characterized in that the main The test container has a liquid addition port for adding the foaming agent solution. A plug cover is detachably installed at the liquid addition port, and the test particle container is installed on the plug cover.

5. The foaming agent performance testing device according to claim 3, characterized in that, The test particle container is fixedly arranged in the main test container, and the outlet is arranged downward. A blocking member is movably arranged in the test particle container. The blocking member has an open position for opening the outlet and a blocking position for blocking the outlet during its moving stroke.

6. The foaming agent performance testing device according to claim 5, characterized in that, The blocking member includes a blocking portion and a magnetic attraction matching portion. The blocking portion is used to block and open the outlet, and the magnetic attraction matching portion is used to cooperate with a magnet to drive the blocking member to move from the blocking position to the open position through magnetic attraction.

7. The foaming agent performance testing device according to claim 6, characterized in that, The blocking member is movably arranged up and down in the test particle container. The magnetic attraction matching portion is arranged at the upper end of the blocking member, and the plug cover is opposite to the magnetic attraction matching portion up and down.

8. The foaming agent performance testing device according to claim 5, characterized in that, The test particle container includes a main body portion and a straight pipe portion. The outer diameter of the main body portion is larger than that of the straight pipe portion, and the outlet is arranged on the straight pipe portion.

9. The foaming agent performance testing device according to claim 2, characterized in that, The caliber of the outlet is adapted to the particle size of the solid test particles.

10. The foaming agent performance testing device according to claim 2, characterized in that, The particle size of the solid test particles is 2 - 4 mm.

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