Method and device for determining gas content in paper pulp fiber suspension

Abstract

The invention relates to the technical field of suspension gas content determination, in particular to a method and a device for determining the gas content in paper pulp fiber suspension.The device comprises a rotatable container, the top end of the container is spirally connected with a hole cover capable of being opened, and the top end of the container is communicated with a negative pressure cylinder through a negative pressure pipe; an annular outer hole plate is fixedly connected to the inner wall of the container through a connecting rod, a gap exists between the outer side of the annular outer hole plate and the inner wall of the container, the bottom of the annular outer hole plate is solid, the upper portion of the annular outer hole plate is exposed, and an inner cavity is formed in the inner side of the annular outer hole plate. According to the invention, the container is rotated, so that liquid in the container is attached to the inner wall of the container, compared with the mode that the liquid is accumulated at the bottom end, the gas-liquid contact area is increased, and the gas-liquid separation efficiency is improved. And meanwhile, the annular outer pore plate is positioned in liquid attached to the side wall of the container.

Description

Technical Field

[0001] This invention relates to the field of gas content determination technology in suspensions, specifically to a method and apparatus for determining the gas content in pulp fiber suspensions. Background Technology

[0002] To measure the gas content in a suspension, a device for measuring the gas content in a pulp fiber suspension, disclosed in CN103439216A, is described. This device seals the pulp fiber suspension to be tested within a sampling cylinder, changes the pressure on the gas in the pulp suspension within the sampling cylinder, causing a change in the gas volume in the pulp fiber suspension, and measures the change in gas volume within the sampling cylinder to determine the gas volume content in the sampling cylinder.

[0003] The above approach suffers from an unavoidable problem that affects measurement accuracy: in a negative pressure environment, the depth of the suspension significantly impacts the escape of free gas. When negative pressure is applied, shallow microbubbles expand and burst more easily, releasing gas. Deeper microbubbles, however, are "suppressed" by greater hydrostatic pressure and may require a higher vacuum to escape. If the negative pressure is insufficient to completely overcome the hydrostatic pressure at that depth, this portion of deep free gas cannot be effectively extracted, leading to lower measurement results.

[0004] This invention greatly increases the accuracy of gas content measurement using the pumping method by reducing the distance between the liquid surface and the gas phase and increasing the contact area between the liquid surface and the gas phase. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for determining the gas content in pulp fiber suspension. By reducing the distance from the liquid surface to the gas phase and increasing the contact area between the liquid surface and the gas phase, this invention greatly increases the accuracy of gas content measurement using the extraction method and the required negative pressure environment.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A device for measuring the gas content in pulp fiber suspension includes a rotatable container with an openable cap screwed to the top of the container. The top of the container is connected to a negative pressure cylinder via a negative pressure pipe, and a solenoid valve for controlling the opening and closing of the negative pressure pipe is installed on the negative pressure pipe. An annular outer perforated plate is fixedly connected to the inner wall of the container by a connecting rod. There is a gap between the outer side of the annular outer perforated plate and the inner wall of the container. The bottom of the annular outer perforated plate is solid and the top is exposed. An inner cavity is opened on the inner side of the annular outer perforated plate. An annular inner perforated plate is slidably connected to the inner side of the annular outer perforated plate. Holes are opened on the inner sides of both the annular outer perforated plate and the annular inner perforated plate. The holes on the annular outer perforated plate and the annular inner perforated plate can be staggered or coincident. The top of the container is equipped with an instant lifting mechanism. After the container reaches the set speed, the instant lifting mechanism can quickly move the annular inner plate upward so that the annular outer plate and the hole on the annular inner plate can be instantly overlapped.

[0007] As a preferred embodiment of the gas content measuring device in pulp fiber suspension of the present invention, the annular inner perforated plate also has two layers, inner and outer, which are connected and fixed by a connecting rod. The bottom and top are exposed. During the accelerated rotation of the container, the holes on the annular outer perforated plate and the annular inner perforated plate are misaligned, and the liquid in the container adheres to the inner wall of the container. This invention rotates the container, causing the liquid inside to adhere to the inner wall of the container. Compared to the liquid accumulating at the bottom, this increases the gas-liquid contact area, while the annular outer perforated plate is positioned within the liquid adhering to the side wall of the container.

[0008] Preferably, in the gas content determination device for pulp fiber suspension of the present invention, after the container is rotated and accelerated to the design speed, under the action of the instantaneous lifting mechanism, the holes on the annular outer perforated plate and the annular inner perforated plate suddenly coincide, the inner cavity opens to the liquid attached to the inner wall of the container, and a negative pressure space the size of the inner cavity suddenly appears in the liquid attached to the inner wall of the container. The liquid does not have time to replenish, and the gas-liquid contact area is further increased in a short time. After the instantaneous lifting mechanism is triggered, the container can be decelerated, the centrifugal force is reduced, the replenishment speed of the liquid to the inner cavity is reduced, the time of the gas phase in the inner cavity is maintained, and because of the existence of the gas cavity, a negative pressure cavity is added inside the liquid, thereby reducing the distance from any position of the liquid to the gas phase, thereby making it easier for free gas to escape and reducing the negative pressure required for escape. A one-way valve is installed at the bottom of the annular outer perforated plate, and a screw-connected cap can also be installed at the bottom of the container for draining the liquid.

[0009] Preferably, in the gas content measuring device of the pulp fiber suspension of the present invention, a support bushing is rotatably connected to the outside of the container. Multiple support bushings can be provided to increase stability. The support bushing is supported by a fixedly connected support frame. A motor is fixedly connected to the center of the support frame. The output end of the motor is fixedly connected to the center of the bottom end of the container. The rotation of the motor drives the container to rotate.

[0010] Preferably, as the gas content measuring device in the pulp fiber suspension of the present invention, a pressure sensor for detecting internal pressure is installed on the negative pressure cylinder, and the negative pressure cylinder is connected to an air extraction nozzle for extracting air.

[0011] Preferably, in the device for measuring the gas content in the pulp fiber suspension of the present invention, a horizontal plate is fixedly connected to the bottom of the container to increase the following performance of the internal liquid when the container is rotated.

[0012] Preferably, as a gas content measuring device in pulp fiber suspension of the present invention, the instantaneous lifting mechanism includes a cylinder fixed to the top of a container. A first slider and a second slider are slidably connected to the inner side of the cylinder. The first slider and the second slider are slidably connected to each other to facilitate gas flow. A first spring is fixedly connected between the first slider and the second slider. A sliding chamber is opened on the inner side of the top of the cylinder. A connecting frame is slidably connected to the sliding chamber. The top of the connecting frame extends out of the cylinder. A first locking block is fixedly connected to the bottom end of the connecting frame on the side away from the negative pressure pipe. In the initial state, the first locking block locks the first slider. The side of the first locking block away from the negative pressure pipe has an inclined surface that facilitates reset. The first spring only stores force when working, which can effectively avoid fatigue of the first spring being in a constrained state for a long time. Preferably, in the gas content measuring device of the pulp fiber suspension of the present invention, a groove is provided on the inner side of the top of the second slider, a second locking block is slidably connected to the inner side of the groove, a second spring is fixedly connected between the second locking block and the bottom of the groove, and a top block is fixedly connected to the side of the first slider away from the negative pressure tube, the top block being wedge-shaped.

[0013] During the accelerated rotation of the container, the suspension not only adheres to the side wall of the container, but also, under the action of centrifugal force, the second slider moves away from the negative pressure tube, compressing the first spring. When the second block passes the sliding chamber, the circuit of the second slider is locked, ensuring that all the elastic potential energy of the first spring is applied to the first slider. The second spring bounces up, causing the connecting frame to move upward, the first block disengages from the first slider, and the first spring is released elastically. The weight of the first slider is preset to ensure that it can effectively compress the first spring. The first slider moves rapidly toward the inner side of the inner hollow plate, causing the inner hollow plate to move upward and driving the annular inner hole plate to move upward rapidly. The annular inner hole plate is made of thin metal, has low weight, and is easy to lift quickly. Preferably, in the device for determining the gas content in pulp fiber suspension of the present invention, a lifting rod is fixedly connected to the top of the annular inner perforated plate. The lifting rod is slidably connected to the inner side of the top of the container and sealed. The top of the lifting rod passes through the inner side of the top of the container and is fixedly connected to an inner hollow plate. After the container rotates to the designed speed, the top block moves rapidly to the side away from the negative pressure pipe, passes through the inner hollow plate and causes the inner hollow plate to move rapidly upward, so that the outer plate of the perforated plate and the hole on the annular inner perforated plate can be instantly overlapped.

[0014] When resetting, press down on the connecting bracket to return the second locking block to the slide groove. The second slider will reset under the action of the first spring. Push the top block by hand to reset the first slider. A method for determining the gas content in a pulp fiber suspension, comprising the following steps: Step 1: Loading: Open the orifice cover and let the fixed volume of suspension fall into the inside of the container through the orifice cover, then close the orifice cover again; Step 2: Negative pressure initialization. Connect the negative pressure cylinder to an external air pump through the suction nozzle. Refer to the pressure sensor reading to maintain the negative pressure cylinder at the designed negative pressure value. Step 3: Accelerate the rotation. The motor starts working, causing the container to rotate and accelerate. At the beginning of the rotation, open the solenoid valve on the negative pressure pipe to apply negative pressure to the container. During the accelerated rotation of the container, the holes on the annular outer orifice plate and the annular inner orifice plate are misaligned. The liquid in the container will adhere to the inner wall of the container under the action of centrifugal force, thereby increasing the gas-liquid contact area. At the same time, the annular outer orifice plate will be in the liquid adhering to the side wall of the container. Step 4: Instant Lift. After the container rotates and accelerates to the designed speed, under the action of the instant lifting mechanism, the holes on the annular outer orifice plate and the annular inner orifice plate suddenly coincide. The inner cavity opens to the liquid attached to the inner wall of the container, and a negative pressure space the size of the inner cavity suddenly appears in the liquid attached to the inner wall of the container. The liquid cannot replenish it in time, which further increases the gas-liquid contact area and reduces the distance from any position of the liquid to the gas phase. This makes it easier for free gas to escape and reduces the negative pressure required for escape. Step 5: Reset; To determine the test, a certain amount of pure water is slowly added to the container before the test. The pure water does not contain suspended gas and has the same volume as the suspension to be tested. After the solenoid valve is opened, the pressure value P1 is obtained through the pressure sensor. After a certain amount of suspension is added to the container, the solenoid valve is opened and after the above steps, the pressure value P2 is obtained by the pressure sensor. By comparing the values ​​of P2 and P1, we can determine whether the gas content of the suspension is high or low. The greater the value of P2 compared to P1, the higher the gas content in the suspension.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. The device for measuring the gas content in pulp fiber suspension. This invention rotates the container so that the liquid inside the container adheres to the inner wall of the container. Compared with the liquid accumulating at the bottom, this increases the gas-liquid contact area. At the same time, the annular outer perforated plate is located in the liquid adhering to the side wall of the container.

[0016] 2. In this device for measuring the gas content in pulp fiber suspension, under the action of the instantaneous lifting mechanism, the holes on the annular outer perforated plate and the annular inner perforated plate suddenly overlap, opening the inner cavity to the liquid adhering to the inner wall of the container. A negative pressure space the size of the inner cavity suddenly appears in the liquid adhering to the inner wall of the container. The liquid cannot replenish in time, further increasing the gas-liquid contact area in a short period of time. After the instantaneous lifting mechanism is triggered, the container can be decelerated, reducing the centrifugal force and decreasing the rate at which the liquid replenishes to the inner cavity, maintaining the time of the gas phase in the inner cavity. Furthermore, due to the existence of the gas cavity, a negative pressure cavity is added inside the liquid, thereby reducing the distance from any position of the liquid to the gas phase, making it easier for free gas to escape and reducing the negative pressure required for escape. A one-way valve is installed at the bottom of the annular outer perforated plate, and a screw-connected cap can also be installed at the bottom of the container for draining the liquid.

[0017] 3. In this device for measuring the gas content in pulp fiber suspension, during the accelerated rotation of the container, the suspension not only adheres to the side wall of the container, but also, under the action of centrifugal force, the second slider moves away from the negative pressure tube, compressing the first spring. When the second locking block passes the sliding chamber, the circuit of the second slider is locked, ensuring that all the elastic potential energy of the first spring is applied to the first slider. The second spring bounces up, causing the connecting frame to move upward, the first locking block disengages from the first slider, and the first spring is released elastically. The weight of the first slider is preset to ensure that it can effectively compress the first spring. The first slider moves quickly towards the inner side of the inner hollow plate, causing the inner hollow plate to move upward and driving the annular inner hole plate to move upward quickly. The annular inner hole plate is made of thin metal, has low weight, and is easy to lift quickly. 4. The device for determining the gas content in pulp fiber suspension determines that, before testing, a fixed amount of pure water is slowly added to the container. The pure water does not contain suspended gas and its volume is consistent with that of the suspension to be tested. After the solenoid valve is opened, the pressure value P1 is obtained through the pressure sensor. After a fixed amount of suspension is added to the container, the solenoid valve is opened and the above steps are followed. The pressure value P2 is obtained through the pressure sensor. By comparing the values ​​of P2 and P1, the amount of gas in the suspension can be determined. The greater the value of P2 compared to P1, the greater the gas content in the suspension. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall appearance and structure of the present invention; Figure 2 This is a cross-sectional view of the container of the present invention; Figure 3 This is a cross-sectional structural schematic diagram of the instantaneous lifting mechanism of the present invention; Figure 4 For the present invention Figure 3 A magnified structural diagram at point A; Figure 5 This is a schematic diagram of the external structure of the annular outer perforated plate of the present invention; Figure 6 This is a cross-sectional view of one side of the annular outer perforated plate of the present invention; Figure 7 For the present invention Figure 6 A magnified structural diagram at point B; Figure 8 This is a schematic diagram of the structure of the instantaneous lifting mechanism of the present invention during preparation and operation. Figure 9 This is a schematic diagram of the structure of the instantaneous lifting mechanism of the present invention during reset.

[0019] In the diagram: 1. Support frame; 2. Motor; 3. Support bushing; 4. Container; 5. Orifice cover; 6. Cylinder; 7. Inner hollow plate; 8. Annular outer orifice plate; 81. Inner cavity; 9. Negative pressure cylinder; 10. Pressure sensor; 11. Air extraction nozzle; 12. Annular inner orifice plate; 121. Lifting rod; 13. Orifice; 14. One-way valve; 15. Horizontal plate; 16. Negative pressure pipe; 61. Top block; 62. First slider; 63. First spring; 64. Second slider; 65. Connecting frame; 66. First locking block; 67. Second spring; 68. Second locking block. Detailed Implementation

[0020] The technical solutions of the embodiments 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, and 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.

[0021] Example 1, please refer to Figure 1 , Figure 2 , Figures 5-7 The present invention provides a technical solution: A device for measuring the gas content in pulp fiber suspension includes a rotatable container 4, with an openable cap 5 screwed to the top of the container 4, and a negative pressure cylinder 9 connected to the top of the container 4 via a negative pressure pipe 16. A solenoid valve for controlling the opening and closing of the negative pressure pipe 16 is installed on the negative pressure pipe 16. An annular outer perforated plate 8 is fixedly connected to the inner wall of container 4 by a connecting rod. There is a gap between the outer side of the annular outer perforated plate 8 and the inner wall of container 4. The bottom of the annular outer perforated plate 8 is solid and the top is exposed. An inner cavity 81 is opened on the inner side of the annular outer perforated plate 8. An annular inner perforated plate 12 is slidably connected to the inner side of the annular outer perforated plate 8. Holes 13 are opened on the inner sides of both the annular outer perforated plate 8 and the annular inner perforated plate 12. The holes 13 on the annular outer perforated plate 8 and the annular inner perforated plate 12 can be staggered or coincident. The top of the container 4 is equipped with an instant lifting mechanism. After the container 4 reaches the set speed, the instant lifting mechanism can quickly move the annular inner hole plate 12 upward, so that the annular outer hole plate 8 and the hole 13 on the annular inner hole plate 12 can be instantly overlapped.

[0022] As a preferred device for measuring the gas content in pulp fiber suspension of the present invention, the annular inner perforated plate 12 is also composed of two layers, inner and outer, which are connected and fixed by a connecting rod. The bottom and top are exposed. During the accelerated rotation of the container 4, the annular outer perforated plate 8 and the holes 13 on the annular inner perforated plate 12 are misaligned, and the liquid in the container 4 adheres to the inner wall of the container 4. The present invention rotates the container 4, causing the liquid inside the container 4 to adhere to the inner wall of the container 4. Compared with the liquid accumulating at the bottom, this increases the gas-liquid contact area. At the same time, the annular outer perforated plate 8 will be in the liquid adhering to the side wall of the container 4.

[0023] Preferably, in the device for determining the gas content in the pulp fiber suspension of the present invention, after the container 4 is rotated and accelerated to the design speed, under the action of the instant lifting mechanism, the holes 13 on the annular outer perforated plate 8 and the annular inner perforated plate 12 suddenly overlap, and the inner cavity 81 opens to the liquid attached to the inner wall of the container 4. A negative pressure space of the size of the inner cavity 81 suddenly appears in the liquid attached to the inner wall of the container 4. The liquid cannot replenish in time, and the gas-liquid contact area is further increased in a short time. After the instant lifting mechanism is triggered, the container 4 can be decelerated, the centrifugal force is reduced, the replenishment speed of the liquid to the inner cavity 81 is reduced, and the time of the gas phase in the inner cavity 81 is maintained. Moreover, because of the existence of the gas cavity 81, a negative pressure cavity is added inside the liquid, thereby reducing the distance from any position of the liquid to the gas phase, thereby making it easier for free gas to escape and reducing the negative pressure required for escape. A one-way valve 14 is installed at the bottom of the annular outer perforated plate 8. The one-way valve 14 can be used for the reflux of the suspension. A spirally connected hole cover 5 can also be installed at the bottom of the container 4 for discharging liquid.

[0024] Preferably, in the device for measuring the gas content in pulp fiber suspension of the present invention, a support bushing 3 is rotatably connected to the outside of the container 4. Multiple support bushings 3 can be provided to increase stability. The support bushing 3 is supported by a fixedly connected support frame 1. A motor 2 is fixedly connected to the center of the support frame 1. The output end of the motor 2 is fixedly connected to the center of the bottom end of the container 4. The rotation of the motor 2 drives the container 4 to rotate.

[0025] Preferably, as a gas content measuring device in pulp fiber suspension of the present invention, a pressure sensor 10 for detecting internal pressure is installed on the negative pressure cylinder 9, and the negative pressure cylinder 9 is connected to an air extraction nozzle 13 for extracting air.

[0026] Preferably, in the device for measuring the gas content in the pulp fiber suspension of the present invention, a horizontal plate 15 is fixedly connected to the bottom end of the container 4 to increase the following of the internal liquid when the container 4 rotates.

[0027] Example 2 is a further improvement upon Example 1. Please refer to Example 1. Figures 1-9 The instant lifting mechanism includes a cylinder 6 fixed to the top of the container 4. A first slider 62 and a second slider 64 are slidably connected to the inner side of the cylinder 6. The first slider 62 and the second slider 64 are slidably connected to each other to facilitate gas flow. A first spring 63 is fixedly connected between the first slider 62 and the second slider 64. A sliding chamber is opened on the inner side of the top of the cylinder 6. A connecting frame 65 is slidably connected to the sliding chamber. The top of the connecting frame 65 extends out of the cylinder 6. A first locking block 66 is fixedly connected to the bottom end of the connecting frame 65 on the side away from the negative pressure pipe 16. In the initial state, the first locking block 66 locks the first slider 62. The side of the first locking block 66 away from the negative pressure pipe 16 has an inclined surface that facilitates reset. The first spring 63 only stores force when working, which can effectively avoid fatigue of the first spring 63 being in a constrained state for a long time. Preferably, in the gas content measuring device of the pulp fiber suspension of the present invention, a groove is provided on the inner side of the top of the second slider 64, a second locking block 68 is slidably connected to the inner side of the groove, a second spring 67 is fixedly connected between the second locking block 68 and the bottom end of the groove, and a top block 61 is fixedly connected to the side of the first slider 62 away from the negative pressure tube 16, the top block 61 being wedge-shaped.

[0028] During the accelerated rotation of container 4, the suspension not only adheres to the side wall of container 4, but also, under the action of centrifugal force, the second slider 64 moves away from the negative pressure pipe 16, compressing the first spring 63. When the second locking block 68 passes the sliding chamber, the circuit of the second slider 64 is locked, ensuring that the elastic potential energy of the first spring 63 is fully applied to the first slider 62. The second spring 67 springs up, causing the connecting frame 65 to move upward, the first locking block 66 disengages from the first slider 62, and the first spring 63 is released elastically. The weight of the first slider 62 is preset to ensure that it can effectively compress the first spring 63. The first slider 62 moves rapidly toward the inner side of the inner hollow plate 7, causing the inner hollow plate 7 to move upward and driving the annular inner hole plate 12 to move upward rapidly. The annular inner hole plate 12 is made of thin metal, has low weight, and is easy to lift quickly. Preferably, in the device for measuring the gas content in the pulp fiber suspension of the present invention, a lifting rod 121 is fixedly connected to the top of the annular inner perforated plate 12. The lifting rod 121 is slidably connected to the inner side of the top of the container 4 and is sealed. The top of the lifting rod 121 passes through the inner side of the top of the container 4 and is fixedly connected to an inner hollow plate 7. After the container rotates to the designed speed, the top block 61 moves rapidly away from the negative pressure pipe 16, passes through the inner hollow plate 7 and causes the inner hollow plate 7 to move rapidly upward, so that the outer perforated plate 8 and the hole 13 on the annular inner perforated plate 12 can be instantly overlapped.

[0029] When resetting, press down on the connecting bracket 65 to return the second locking block 68 to the slide groove, and the second slider 64 will reset under the action of the first spring 63. Push the top block 61 by hand to reset the first slider 62. This invention also discloses a method for determining the gas content in pulp fiber suspension, the steps of which are: Step 1: Feeding: Open the orifice cover 5 and let the fixed volume of suspension fall into the inside of the container 4 through the orifice cover 5, then close the orifice cover 5 again. Step 2: Negative pressure initialization. Connect the negative pressure cylinder 9 to the external air pump through the air extraction nozzle 11. Refer to the reading of the pressure sensor 10 to maintain the negative pressure cylinder 9 at the designed negative pressure value. Step 3: Accelerate rotation. Motor 2 works to make container 4 rotate and accelerate. At the start of rotation, the solenoid valve on the negative pressure pipe 16 is opened to allow negative pressure to be applied to container 4. During the accelerated rotation of container 4, the holes 13 on the annular outer perforated plate 8 and the annular inner perforated plate 12 are misaligned. The liquid in container 4 will adhere to the inner wall of container 4 under the action of centrifugal force, thereby increasing the gas-liquid contact area. At the same time, the annular outer perforated plate 8 will be in the liquid adhering to the side wall of container 4. Step 4: Instant lifting. After the container 4 rotates and accelerates to the designed speed, under the action of the instant lifting mechanism, the holes 13 on the annular outer orifice plate 8 and the annular inner orifice plate 12 suddenly coincide. The inner cavity 81 opens to the liquid attached to the inner wall of the container 4. A negative pressure space of the size of the inner cavity 81 suddenly appears in the liquid attached to the inner wall of the container 4. The liquid cannot be replenished in time, which further increases the gas-liquid contact area and reduces the distance from any position of the liquid to the gas phase. This makes it easier for the free gas to escape and reduces the negative pressure required for escape. Step 5: Reset; Before testing, a certain amount of pure water is slowly added to container 4. The water outlet pipe can be inserted into the cap 5 to allow water to flow out, reducing the amount of gas trapped in the liquid during the addition process. The pure water does not contain suspended gas and has the same volume as the suspension to be tested. After the solenoid valve is opened, the pressure value P1 is obtained through the pressure sensor 10. After a certain amount of suspension is added to container 4, if the suspension does not fill container 4, the solenoid valve opens and after the above steps, the pressure value P2 at this time is obtained by pressure sensor 10. By comparing the values ​​of P2 and P1, we can determine whether the gas content of the suspension is high or low. The greater the value of P2 compared to P1, the higher the gas content in the suspension.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for measuring the gas content in pulp fiber suspension, comprising a rotatable container (4), characterized in that: The top of the container (4) is screwed with an openable cap (5), and the top of the container (4) is connected to a negative pressure cylinder (9) through a negative pressure pipe (16). A solenoid valve for controlling the opening and closing of the negative pressure pipe (16) is installed on the negative pressure pipe (16). An annular outer perforated plate (8) is fixedly connected to the inner wall of the container (4) by a connecting rod. There is a gap between the outer side of the annular outer perforated plate (8) and the inner wall of the container (4). The bottom of the annular outer perforated plate (8) is solid and the top is exposed. An inner cavity (81) is opened on the inner side of the annular outer perforated plate (8). An annular inner perforated plate (12) is slidably connected to the inner side of the annular outer perforated plate (8). Holes (13) are opened on the inner sides of both the annular outer perforated plate (8) and the annular inner perforated plate (12). The holes (13) on the annular outer perforated plate (8) and the annular inner perforated plate (12) can be staggered or overlapped. The top of the container (4) is provided with an instant lifting mechanism. After the container (4) reaches the set speed, the instant lifting mechanism can quickly move the annular inner hole plate (12) upward so that the annular outer hole plate (8) and the hole (13) on the annular inner hole plate (12) can be instantly overlapped.

2. The device for determining the gas content in pulp fiber suspension according to claim 1, characterized in that: The annular inner perforated plate (12) is also composed of two layers, inner and outer, which are connected and fixed by a connecting rod. The bottom and top are exposed. During the accelerated rotation of the container (4), the annular outer perforated plate (8) and the hole (13) on the annular inner perforated plate (12) are misaligned. The liquid in the container (4) adheres to the inner wall of the container (4). Compared with the liquid accumulating at the bottom, the gas-liquid contact area is increased. At the same time, the annular outer perforated plate (8) will be in the liquid adhering to the side wall of the container (4).

3. The device for determining the gas content in pulp fiber suspension according to claim 2, characterized in that: After the container (4) is rotated and accelerated to the design speed, under the action of the instant lifting mechanism, the holes (13) on the annular outer hole plate (8) and the annular inner hole plate (12) suddenly overlap, and the inner cavity (81) opens to the liquid attached to the inner wall of the container (4). A negative pressure space of the size of the inner cavity (81) suddenly appears in the liquid attached to the inner wall of the container (4). The liquid cannot be replenished in time, and the gas-liquid contact area is further increased in a short time, and the distance from any position of the liquid to the gas phase is reduced, so that the free gas can escape more easily and the negative pressure required for escape is reduced.

4. The apparatus for determining the gas content in pulp fiber suspension according to any one of claims 1-3, characterized in that: The outer side of the container (4) is rotatably connected to a support bushing (3), which is supported by a fixed support frame (1). A motor (2) is fixedly connected to the center of the support frame (1), and the output end of the motor (2) is fixedly connected to the center of the bottom of the container (4). The container (4) is driven to rotate by the rotation of the motor (2).

5. The apparatus for determining the gas content in pulp fiber suspension according to any one of claims 1-3, characterized in that: A pressure sensor (10) for detecting internal pressure is installed on the negative pressure cylinder (9), and the negative pressure cylinder (9) is connected to an air extraction nozzle (13) for evacuation.

6. The apparatus for determining the gas content in pulp fiber suspension according to any one of claims 1-3, characterized in that: A horizontal plate (15) is fixedly connected to the bottom of the container (4) to increase the following of the internal liquid when the container (4) rotates.

7. The apparatus for determining the gas content in pulp fiber suspension according to any one of claims 1-3, characterized in that: The instant lifting mechanism includes a cylinder (6) fixed to the top of the container (4). A first slider (62) and a second slider (64) are slidably connected to the inner side of the cylinder (6). The first slider (62) and the second slider (64) are connected to each other from left to right to facilitate gas flow. A first spring (63) is fixedly connected between the first slider (62) and the second slider (64). A sliding chamber is opened on the inner side of the top of the cylinder (6). A connecting frame (65) is slidably connected in the sliding chamber. The top of the connecting frame (65) extends out of the cylinder (6). A first locking block (66) is fixedly connected to the bottom of the connecting frame (65) away from the negative pressure pipe (16). In the initial state, the first locking block (66) locks the first slider (62).

8. The apparatus for determining the gas content in pulp fiber suspension according to claim 7, characterized in that: The top inner side of the second slider (64) is provided with a groove, and the inner side of the groove is slidably connected to a second locking block (68). A second spring (67) is fixedly connected between the second locking block (68) and the bottom end of the groove. A top block (61) is fixedly connected to the side of the first slider (62) away from the negative pressure pipe (16). The top block (61) is wedge-shaped.

9. The apparatus for determining the gas content in pulp fiber suspension according to claim 8, characterized in that: A lifting rod (121) is fixedly connected to the top of the annular inner plate (12). The top of the lifting rod (121) passes through the inner side of the top of the container (4) and is fixedly connected to the inner hollow plate (7). After the container rotates to the designed speed, the top block (61) moves quickly away from the negative pressure pipe (16), passes through the inner hollow plate (7) and causes the inner hollow plate (7) to move up quickly, so that the outer plate (8) of the shaped hole and the hole (13) on the annular inner plate (12) can be instantly superimposed.

10. A method for determining the gas content in a pulp fiber suspension, using the gas content measuring device according to claim 9, characterized in that, The steps are as follows: Step 1: Loading: Open the orifice cover (5) and let the fixed volume of suspension fall into the inside of the container (4) through the orifice cover (5), then close the orifice cover (5) again. Step 2: Negative pressure initialization. Connect the negative pressure cylinder (9) to the external air pump through the air extraction nozzle (11). Refer to the reading of the pressure sensor (10) to maintain the negative pressure cylinder (9) at the designed negative pressure value. Step 3: Accelerate the rotation. The motor (2) works to make the container (4) rotate and accelerate. When the rotation starts, open the solenoid valve on the negative pressure pipe (16) so that the negative pressure is applied to the container (4). During the accelerated rotation of the container (4), the holes (13) on the annular outer perforated plate (8) and the annular inner perforated plate (12) are in a staggered state. The liquid in the container (4) will adhere to the inner wall of the container (4) under the action of centrifugal force, thereby increasing the gas-liquid contact area. At the same time, the annular outer perforated plate (8) will be in the liquid attached to the side wall of the container (4). Step 4: Instant lifting. After the container (4) is rotated and accelerated to the design speed, under the action of the instant lifting mechanism, the holes (13) on the annular outer perforated plate (8) and the annular inner perforated plate (12) suddenly overlap. The inner cavity (81) opens to the liquid attached to the inner wall of the container (4). A negative pressure space of the size of the inner cavity (81) suddenly appears in the liquid attached to the inner wall of the container (4). The liquid cannot be replenished in time, further increasing the gas-liquid contact area and reducing the distance from any position of the liquid to the gas phase. This makes it easier for the free gas to escape and reduces the negative pressure required for escape. Step 5: Reset.

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