A device for measuring the permeability of a pulp fiber layer

Abstract

The application discloses a kind of paper pulp fiber layer permeability measuring device, measuring device includes measuring cylinder, the water inlet of measuring cylinder is connected with diaphragm pump, the other end of diaphragm pump is connected with water bucket, the air inlet of measuring cylinder is connected with high-pressure gas source by electromagnetic valve, the outlet of overflow pipe of measuring cylinder is provided with liquid storage barrel, liquid storage barrel is placed on electronic balance, pressure sensor is provided on measuring cylinder. By lifting lifting presser to pulp inlet, water is added to pulp inlet, until water overflows from overflow pipe;Add required paper pulp fiber to pulp inlet, stand, according to the position information of porous piston, rotate lifting presser to required position;Calculate the permeability of paper pulp fiber concentration. Based on Darcy's law, paper pulp fiber layer thickness, filter pressure, overflow flow rate and liquid viscosity to determine the permeability of specified paper pulp fiber layer mass concentration, can quickly, high-precision paper pulp fiber layer is compressed to required thickness, accurate, simple and convenient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of permeability measurement, in particular to a paper pulp fiber layer permeability measurement device. BACKGROUND

[0002] Plastic products have been widely used in the packaging field due to their low cost and excellent packaging performance, but the corresponding environmental problems have also become increasingly apparent. In recent years, with the continuous implementation of national environmental protection policies and the enhancement of consumers' environmental protection awareness, pollution-free and non-harmful "green packaging" has received more and more attention and attention. Paper pulp molded products are a kind of packaging materials made of primary or secondary fibers as the main raw material, and the fibers are dehydrated and formed by a special mold, and then dried and shaped. Because of the advantages of renewable raw materials and degradable products, paper pulp molded products have become the most potential green packaging materials to replace plastic products in the packaging market.

[0003] Paper pulp molded products are generally prepared by processes such as pulp preparation, molding, drying, shaping and post-processing. At present, the molding process of paper pulp molded products mainly adopts vacuum molding, that is, the lower mold of the mold is immersed in the pulp pool, and the fibers in the pulp pool are uniformly adsorbed on the surface of the lower mold by negative pressure, and then the upper mold is combined with the lower mold. In the process of vacuum molding, the suction forming process of wet paper pulp fibers in the pulp pool is one of the key steps that affect the quality of paper pulp molding. Computer simulation (simulation) research can establish a mathematical model to describe the forming process of paper pulp fibers according to the existing filtration theory, simulate the whole process of suction forming, and provide a new way for the quality control of wet paper pulp forming. The permeability of the paper pulp fiber layer is one of the key parameters of the mathematical model of the filtration theory. Therefore, a paper pulp fiber layer permeability measurement method and device are urgently needed to quickly, simply and accurately measure the permeability of the paper pulp fiber layer, provide necessary basic experimental data for quality control and computer-aided design of the suction forming process, and further understand the suction forming mechanism and realize accurate control of the suction forming process. SUMMARY

[0004] The present application provides a paper pulp fiber layer permeability measurement device for quickly, simply and accurately measuring the permeability of the paper pulp fiber layer.

[0005] To achieve the above object, the present application is realized by the following technical scheme: a paper pulp fiber layer permeability measurement method, comprising the following steps:

[0006] S1: lifting the lifting and pressing piece above the pulp adding port, adding water to the pulp adding port, and overflowing the water from the overflow pipe;

[0007] S2: adding the required paper pulp fiber to the pulp adding port, standing, and rotating the lifting and pressing piece to the required position according to the position information of the porous piston;

[0008] S3: Calculate the permeability of the pulp fiber concentration.

[0009] Preferably, the S1 comprises:

[0010] S11: Rotate the lifting and pressing part to above the pulp inlet, fasten the first flange and the second flange;

[0011] S12: Place the measuring cylinder vertically on the support, and place the liquid storage barrel and the electronic balance directly below the overflow pipe;

[0012] S13: Slowly add water to the pulp inlet until water overflows from the overflow pipe.

[0013] Preferably, the S2 comprises:

[0014] S21: Add the required pulp fiber to the pulp inlet and stand still;

[0015] S22: After the pulp fiber suspension is clearly stratified, close the sealing cover of the pulp inlet;

[0016] S23: Run the software program in the computer, set the air pressure and monitor the position of the porous piston, according to the position information of the porous piston, rotate the lifting and pressing part to the required position, i.e. compress the pulp fiber layer to the specified thickness.

[0017] Preferably, the S3 comprises:

[0018] S31: Keep the air pressure and the liquid level on the upper layer of the pulp fiber layer basically stable, wait until the liquid flow rate of the overflow pipe is stable, and record the overflow flow rate through the electronic balance, i.e. the filtrate mass per unit time;

[0019] S32: Based on the filtration pressure, the thickness of the pulp fiber layer, the overflow flow rate, the liquid viscosity and the filtration area data, obtain the permeability of a certain pulp fiber concentration according to Darcy's law.

[0020] A measuring device for measuring the permeability of a pulp fiber layer, for realizing a method for measuring the permeability of a pulp fiber layer;

[0021] The measuring device comprises a measuring cylinder, the water inlet of the measuring cylinder is connected with a diaphragm pump, the other end of the diaphragm pump is connected with a water barrel, the air inlet of the measuring cylinder is connected with a high-pressure gas source through an electromagnetic valve, a liquid storage barrel is arranged at the outlet of the overflow pipe of the measuring cylinder, the liquid storage barrel is placed on an electronic balance, and a pressure sensor is arranged on the measuring cylinder.

[0022] Preferably, the measuring cylinder comprises a top cover, an upper cylinder and a lower cylinder, the top cover is connected with the upper cylinder through a first flange, the upper cylinder is connected with the lower cylinder through a second flange, the side wall of the upper cylinder is provided with an air inlet, a pressure sensor, a water inlet, a liquid level sensor and a pulp adding port, the top end of the top cover is provided with a distance measuring sensor, the signal lines of the pressure sensor, the distance measuring sensor and the liquid level sensor are connected with a data acquisition card, the control line of the electromagnetic valve is connected with the data acquisition card through a first solid-state relay, the power line of the diaphragm pump is connected with the data acquisition card through a second solid-state relay, and the data acquisition card is connected with a computer.

[0023] Preferably, the top cover is provided with a lifting and pressing element, the lifting and pressing element comprises a screw sleeve, the screw sleeve is fixedly connected to the inner side of the top end of the top cover, a screw rod is rotatably connected in the screw sleeve, a hand wheel is fixedly connected to the upper end of the screw rod, a screw connecting piece is rotatably connected to the lower end of the screw rod, a light rod is fixedly connected to the lower end of the screw connecting piece, the lower end of the light rod is fixed on a multi-hole piston, and the lower end of the multi-hole piston is fixed with a multi-hole net.

[0024] Preferably, the distance measuring sensor is used to measure the moving distance of the hand wheel on the lifting and pressing element, the position of the multi-hole piston is determined by determining the position of the hand wheel, so as to determine the thickness of the fiber layer, the pressure sensor is used to measure the air pressure in the cylinder, and the electronic balance is used to record the quality of the overflowed filtrate;

[0025] The data acquisition card controls the on-off of the first solid-state relay according to the signal fed back by the pressure sensor, so as to keep the air pressure stable during the measurement, and the data acquisition card controls the on-off of the second solid-state relay according to the signal fed back by the liquid level sensor, so as to control the start and stop of the diaphragm pump, and the liquid level on the multi-hole piston is kept stable.

[0026] Preferably, the first silica gel pad, the filter screen, the multi-hole support and the second silica gel pad are sequentially arranged in the second flange from top to bottom;

[0027] The multi-hole support is a rigid multi-hole plate with pressure resistance and corrosion resistance, and the outer diameter of the filter screen is larger than the inner diameter of the lower cylinder;

[0028] The first silica gel pad and the second silica gel pad are both in the form of a circular ring, the outer diameters of the first silica gel pad and the second silica gel pad are both larger than the filter screen, the outer diameters of the first silica gel pad and the second silica gel pad are both smaller than the diameter of the second flange, and the inner diameters of the first silica gel pad and the second silica gel pad are the same as the inner diameter of the lower cylinder, so as to seal the flange.

[0029] Preferably, the bottom of the lower cylinder is provided with an opening, the opening of the bottom of the lower cylinder is connected with an overflow pipe, the outlet of the overflow pipe is higher than the top end of the flange of the lower cylinder, and is arranged directly above the liquid storage barrel;

[0030] The filling opening is equipped with a sealing cover. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Flow chart of the method of the present application;

[0032] Figure 2 Schematic diagram of the measuring structure of the device of the present application;

[0033] Figure 3 Schematic diagram of the measuring cylinder structure of the present application;

[0034] Figure 4 Schematic diagram of the structure arranged between the second flanges of the present application;

[0035] Figure 5 Schematic diagram of the connecting device structure of the present application.

[0036] In the figure: 1, measuring cylinder; 2, liquid storage barrel; 3, electronic balance; 4, electromagnetic valve; 5, high-pressure gas source; 6, diaphragm pump; 7, data acquisition card; 8, computer; 9, first solid-state relay; 10, second solid-state relay; 11, upper cover; 12, upper cylinder; 13, lower cylinder; 14, air inlet; 15, water inlet; 16, filling opening; 17, lifting and pressing piece; 18, overflow pipe; 19, pressure sensor; 20, distance measuring sensor; 21, first flange; 22, second flange; 23, liquid level sensor; 24, connecting device; 161, sliding plate; 171, hand wheel; 172, screw rod; 173, screw rod sleeve; 174, screw rod connecting piece; 175, light pole; 176, porous piston; 221, first silica gel pad; 222, filter screen; 223, porous support; 224, second silica gel pad; 2401, pull block; 2402, pressing plate; 2403, limiting block; 2404, sleeve; 2405, first connecting rod; 2406, housing; 2407, insertion rod; 2408, clamping block; 2409, first spring; 2410, clamping rod; 2411, inclined chute; 2412, second spring; 2413, push block; 2414, connecting lever; 2415, third spring; 2416, second connecting rod; 2417, wedge-shaped block; 2418, push rod; 2419, clamping block; 2420, fourth spring. DETAILED DESCRIPTION

[0037] The description such as "first", "second" and the like in the present application is only for the purpose of description, and does not mean to particularly indicate the order or sequence, nor to limit the present application, which is merely to distinguish the protective assembly or operation described by the same technical terms, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" can be explicitly or implicitly included at least one of the features. In addition, the technical solutions and technical features of various embodiments can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the scope of protection required by the present application.

[0038] Embodiment 1

[0039] Please refer to Figures 1-4 The present application provides an embodiment: a method for measuring the permeability of pulp fiber layer, comprising the following steps:

[0040] S1: lifting the lifting and pressing part 17 above the pulp inlet 16, adding water to the pulp inlet 16, until the water overflows from the overflow pipe 18;

[0041] S2: adding the required pulp fiber to the pulp inlet 16, standing, rotating the lifting and pressing part 17 to the required position according to the position information of the porous piston 176;

[0042] S3: calculating the permeability of the pulp fiber concentration.

[0043] Preferably, the S1 comprises:

[0044] S11: rotating the lifting and pressing part 17 to lift above the pulp inlet 16, and fastening the first flange 21 and the second flange 22;

[0045] S12: vertically placing the measuring cylinder 1 on the support, and placing the liquid storage barrel 2 and the electronic balance 3 directly below the overflow pipe 18;

[0046] S13: slowly adding water to the pulp inlet 16 until the water overflows from the overflow pipe 18.

[0047] Preferably, the S2 comprises:

[0048] S21: adding the required pulp fiber to the pulp inlet 16, and standing;

[0049] S22: closing the sealing cover of the pulp inlet 16 after the pulp fiber suspension appears obvious stratification;

[0050] S23: running software program in computer 8, setting air pressure and monitoring the position of porous piston 176, according to the position information of porous piston 176, rotating lifting press part 17 to the required position, i.e. compressing the pulp fiber layer to the specified thickness.

[0051] Preferably, S3 comprises:

[0052] S31: keeping the air pressure and the liquid level on the pulp fiber layer basically stable, waiting for the liquid flow rate of overflow pipe 18 to be stable, and then recording the overflow flow rate, i.e. the filtrate mass per unit time, by electronic balance 3;

[0053] S32: based on the filtration pressure △P, the pulp fiber layer thickness H, the overflow flow rate Q, the liquid viscosity μ and the filtration area A data, according to Darcy's law, the permeability K of a certain pulp fiber concentration is obtained.

[0054] The calculation formula of permeability K is as follows:

[0055] K = Q·D·μ / (A·△P)

[0056] Wherein, J is the permeability of a certain pulp fiber concentration, the filtration pressure △P is calculated according to the air pressure in the measuring cylinder 1, the height difference between the outlet of overflow pipe 18 and the filter screen 222, and the height difference between the liquid level sensor 21 and the porous piston 176; the pulp fiber layer thickness H is calculated according to the position of porous piston 176 recorded by distance measuring sensor 20; the filtration area A is calculated according to the inner diameter of upper cylinder 12.

[0057] A kind of measuring device of pulp fiber layer permeability, for realizing a kind of measuring method of pulp fiber layer permeability;

[0058] It comprises measuring cylinder 1, the water inlet 15 of the measuring cylinder 1 is connected with diaphragm pump 6, the other end of the diaphragm pump 6 is connected with water bucket, the air inlet 14 of the measuring cylinder 1 is connected with high-pressure gas source 5 through electromagnetic valve 4, the outlet of overflow pipe 18 of the measuring cylinder 1 is provided with liquid storage barrel 2, the liquid storage barrel 2 is placed on electronic balance 3, and pressure sensor 19 is arranged on the measuring cylinder 1.

[0059] Preferably, the inner diameter of overflow pipe 18 is 10-20mm.

[0060] Preferably, the measuring cylinder 1 comprises a top cover 11, an upper cylinder 12 and a lower cylinder 13, the top cover 11 is connected with the upper cylinder 12 through a first flange 21, the upper cylinder 12 is connected with the lower cylinder 13 through a second flange 22, a gas inlet 14, a pressure sensor 19, a water inlet 15, a liquid level sensor 23 and a pulp adding port 16 are arranged on the side wall of the upper cylinder 12, a distance measuring sensor 20 is arranged on the outside of the top end of the top cover 11, the signal lines of the pressure sensor 19, the distance measuring sensor 20 and the liquid level sensor 23 are connected with a data acquisition card 7, the control line of the electromagnetic valve 4 is connected with the data acquisition card 7 through a first solid-state relay 9, the power line of the diaphragm pump 6 is connected with the data acquisition card 7 through a second solid-state relay 10, and the data acquisition card 7 is connected with a computer 8.

[0061] Preferably, the pulp adding port 16 is arranged at an angle of 30-45° with the side wall of the upper cylinder 12, and the inner diameter of the pulp adding port 16 is greater than or equal to 15mm.

[0062] Preferably, the top cover 11 is provided with a lifting and pressing element 17, the lifting and pressing element 17 comprises a screw sleeve 173, the screw sleeve 173 is fixedly connected to the inside of the top end of the top cover 11, a screw rod 172 is rotatably connected in the screw sleeve 173, a hand wheel 171 is fixedly connected to the upper end of the screw rod 172, a screw connecting piece 174 is rotatably connected to the lower end of the screw rod 172, a light rod 175 is fixedly connected to the lower end of the screw connecting piece 174, and the lower end of the light rod 175 is fixed on a multi-hole piston 176, and the lower end of the multi-hole piston 176 is fixed with a multi-hole mesh.

[0063] Preferably, the mesh of the filter screen is 120-300 mesh.

[0064] Preferably, the multi-hole mesh is 120-300 mesh.

[0065] Preferably, the distance measuring sensor 20 is used to measure the moving distance of the hand wheel 171 on the lifting and pressing element 17, the position of the multi-hole piston 176 is determined by determining the position of the hand wheel 171, so as to determine the thickness of the fiber layer, the pressure sensor 19 is used to measure the air pressure in the cylinder 1, and the electronic balance 3 is used to record the quality of the overflowed filtrate.

[0066] The data acquisition card 7 controls the on-off of the first solid-state relay 9 according to the signal fed back by the pressure sensor 19, so as to keep the air pressure stable during the measurement, and the data acquisition card 7 controls the on-off of the second solid-state relay 10 according to the signal fed back by the liquid level sensor, so as to control the start and stop of the diaphragm pump 6, thereby keeping the liquid level on the multi-hole piston 176 stable.

[0067] Preferably, the first silica gel pad 221, the filter screen 222, the porous support 223 and the second silica gel pad 224 are sequentially arranged in the second flange 22 from top to bottom.

[0068] The porous support 223 is a rigid porous plate resistant to pressure and corrosion, and the outer diameter of the filter screen 222 is larger than the inner diameter of the lower cylinder 13.

[0069] The first silica gel pad 221 and the second silica gel pad 224 are both in the form of a circular ring, and the outer diameter of the first silica gel pad 221 and the second silica gel pad 224 is larger than that of the filter screen 222, and the outer diameter of the first silica gel pad 221 and the second silica gel pad 224 is smaller than the diameter of the second flange 22, and the inner diameter of the first silica gel pad 221 and the second silica gel pad 224 is the same as the inner diameter of the lower cylinder 13, for flange sealing.

[0070] Preferably, the pore size of the porous support 223 is 2-3 mm.

[0071] Preferably, the lower cylinder 13 is provided with an opening at the bottom, and the opening at the bottom of the lower cylinder 13 is connected to the overflow pipe 18, and the outlet of the overflow pipe 18 is higher than the top end of the flange of the lower cylinder 13 and is placed directly above the liquid storage barrel 2.

[0072] The pulp adding port 16 is provided with a sealing cover.

[0073] The working principle and advantages of the above scheme are as follows: the lifting and pressing element 17 is rotated to be lifted above the pulp adding port 16, the first flange 21 and the second flange 22 are fastened, the measuring cylinder 1 is vertically placed on the support, the liquid storage barrel 2 and the electronic balance 3 are placed directly below the overflow pipe 18, water is slowly added to the pulp adding port 16 until the water overflows from the overflow pipe 18; the required paper pulp fibers are added to the pulp adding port 16, and after the paper pulp fiber suspension is clearly layered, the sealing cover of the pulp adding port 16 is closed, the software program in the computer 8 is run, the air pressure is set and the position of the porous piston 176 is monitored, according to the position information of the porous piston 176, the lifting and pressing element 17 is rotated to the required position, i.e. the paper pulp fiber layer is compressed to the specified thickness. The air pressure and the liquid level of the upper layer of the paper pulp fiber layer are basically stable, and after the liquid flow rate of the overflow pipe 18 is stable, the overflow flow rate, i.e. the filtrate quality per unit time, is recorded by the electronic balance 3, and based on the filtration pressure, the thickness of the paper pulp fiber layer, the overflow flow rate, the liquid viscosity and the filtration area data, the permeability of the paper pulp fiber layer at a certain paper pulp fiber concentration is obtained according to Darcy's law.

[0074] Example 2

[0075] Please refer to Figure 5 On the basis of example 1, the sealing cover of the pulp adding port 16 is connected to the pulp adding port 16 through the connecting device 24.

[0076] The connecting device 24 comprises:

[0077] The pull block 2401, the pressing plate 2402, the limiting block 2403, the sleeve 2404, the first connecting rod 2405, the shell 2406, the insertion rod 2407, the clamping block 2408, the first spring 2409, the clamping rod 2410, the inclined slot 2411, the second spring 2412, the pushing block 2413, the connecting rod 2414, the third spring 2415, the second connecting rod 2416, the wedge-shaped block 2417, the pushing rod 2418, the clamping block 2419, the fourth spring 2420;

[0078] The sealing cover of the slurry adding opening 16 is fixedly connected to the shell 2406;

[0079] The sleeve 2404 is slidably connected in the shell 2406, the insertion rod 2407 is inserted in the sleeve 2404, the sleeve 2404 and the insertion rod 2407 penetrate through the shell 2406, and the two ends of the insertion rod 2407 are located outside the sleeve 2404;

[0080] One end of the sleeve 2404 located outside the shell 2406 is fixedly connected with the pressing plate 2402, the fourth spring 2420 is arranged between the pressing plate 2402 and the shell 2406, the fourth spring 2420 is sleeved outside the sleeve 2404, and the two ends of the fourth spring 2420 are fixedly connected to the pressing plate 2402 and the shell 2406 respectively;

[0081] The clamping block 2408 is fixedly connected to the insertion rod 2407, the first spring 2409 is arranged between the clamping block 2408 and the sleeve 2404, the first spring 2409 is sleeved outside the insertion rod 2407, and the two ends of the first spring 2409 are fixedly connected to the clamping block 2408 and the sleeve 2404 respectively;

[0082] The clamping rod 2410 is slidably connected in the shell 2406, one end of the clamping rod 2410 is clamped to the clamping block 2408, and the other end of the clamping rod 2410 is connected to the inner wall of the shell 2406 through the second spring 2412;

[0083] The inclined slot 2411 is arranged on the clamping rod 2410;

[0084] The first connecting rod 2405 is fixedly connected to the pressing plate 2402, the first connecting rod 2405 penetrates through the shell 2406, and one end of the first connecting rod 2405 penetrating through the shell 2406 is located at the entrance of the inclined slot 2411;

[0085] One end of the insertion rod 2407 is fixedly connected with the pull block 2401, the other end of the insertion rod 2407 is fixedly connected with the connecting rod 2414, the pushing block 2413 and the pushing rod 2418 are fixedly connected to the connecting rod 2414;

[0086] The second connecting rod 2416 is rotatably connected in the shell 2406, one end of the second connecting rod 2416 penetrates the shell 2406, and a groove allowing the second connecting rod 2416 to rotate is arranged on the shell 2406;

[0087] One end of the second connecting rod 2416 is fixedly connected with a wedge block 2417, and the end of the second connecting rod 2416 fixedly connected with the wedge block 2417 is connected with the inner wall of the shell 2406 through the third spring 2415, and the wedge block 2417 abuts against the push block 2413;

[0088] The other end of the second connecting rod 2416 is fixedly connected with a clamping block 2419;

[0089] The slidable plate 161 is slidably connected with the slidable plate 161, the push rod 2418 abuts against the slidable plate 161, and the clamping block 2419 is clamped with the slidable plate 161.

[0090] The working principle and beneficial effects of the above-mentioned scheme are as follows: the connecting device 24 drives the sealing cover to be integrally sleeved outside the slurry inlet 16, the first connecting rod 2405 is inserted into the inclined groove 2411 by pressing the pressing plate 2402, the clamping rod 2410 is released from the restriction of the clamping block 2408, the insertion rod 2407 moves under the action of the first spring 2409, the second connecting rod 2416 is deflected through the connecting rod 2414, the push block 2413, the push rod 2418, the wedge block 2417 and the slidable plate 161, the push rod 2418 abuts against the slidable plate 161, and the clamping block 2419 is clamped with the slidable plate 161, thereby completing the sealing of the slurry inlet 16 by the sealing cover;

[0091] When the sealing of the slurry inlet 16 needs to be released, the pull block 2401 is pulled out, the connecting rod 2414 is moved by the insertion rod 2407, the second connecting rod 2416 is reset under the action of the third spring 2415, the push rod 2418 and the clamping block 2419 are released from the restriction of the slidable plate 161, and the sealing of the slurry inlet 16 is released;

[0092] The connecting device 24 is arranged to connect the sealing cover and the slurry inlet 16, so that the operation is more convenient, the operation time is saved, and the accuracy of experimental data is improved.

[0093] It is apparent for those skilled in the art that the present application is not limited to the details of the above-mentioned exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

Claims

1. A device for measuring the permeability of a pulp fiber layer, characterized in that, A method for measuring the permeability of pulp fiber layers; The measuring cylinder (1) includes a measuring cylinder (1), the water inlet (15) of which is connected to a diaphragm pump (6), the other end of which is connected to a water tank, the air inlet (14) of which is connected to a high-pressure air source (5) via a solenoid valve (4), a liquid storage tank (2) is provided at the outlet of the overflow pipe (18) of the measuring cylinder (1), the liquid storage tank (2) is placed on an electronic balance (3), and a pressure sensor (19) is provided on the measuring cylinder (1). The measurement method includes the following steps: S1: Raise the lifting press (17) above the pulp inlet (16), add water to the pulp inlet (16) until the water overflows from the overflow pipe (18); S2: Add the required pulp fibers to the pulp inlet (16), let it stand, and rotate the lifting press (17) to the required position according to the position information of the porous piston (176); S3: Calculate the permeability of pulp fiber concentration; The slurry inlet (16) is equipped with a sealing cap; The sealing cap of the slurry inlet is connected to the slurry inlet via a connecting device; The connecting device includes a housing; The sealing cap of the slurry inlet is fixedly connected to the housing; A sleeve is slidably connected inside the housing, and a rod is inserted into the sleeve. Both the sleeve and the rod penetrate the housing, and both ends of the rod are located outside the sleeve. A pressure plate is fixedly connected to one end of the sleeve outside the housing. A fourth spring is provided between the pressure plate and the housing. The fourth spring is sleeved outside the sleeve, and its two ends are fixedly connected to the pressure plate and the housing, respectively. A locking block is fixedly connected to the insertion rod, and a first spring is provided between the locking block and the sleeve. The first spring is sleeved on the outside of the insertion rod, and both ends of the first spring are fixedly connected to the locking block and the sleeve, respectively. A locking rod is slidably connected inside the housing. One end of the locking rod is engaged with a locking block, and the other end of the locking rod is connected to the inner wall of the housing through a second spring. The lever is provided with a slanted groove; A first connecting rod is fixedly connected to the pressure plate. The first connecting rod penetrates the housing, and one end of the first connecting rod penetrating the housing is located at the inlet of the inclined groove. One end of the insertion rod is fixedly connected to a puller, and the other end of the insertion rod is fixedly connected to a connecting plate. A pusher and a push rod are fixedly connected to the connecting plate. A second connecting rod is rotatably connected inside the housing. One end of the second connecting rod passes through the housing, and the housing is provided with a groove that allows the second connecting rod to rotate. A wedge block is fixedly connected to one end of the second connecting rod, and the end of the second connecting rod with the wedge block is connected to the inner wall of the housing through a third spring. The wedge block abuts against the push block. A locking block is fixedly connected to the other end of the second connecting rod; The slurry inlet is slidably connected to a sliding plate, the push rod abuts against the sliding plate, and the locking block is locked into the sliding plate.

2. The measuring device for the permeability of pulp fiber layer according to claim 1, characterized in that, S1 includes: S11: Rotate the lifting and pressing component (17) to raise it above the pulp inlet (16), and tighten the first flange (21) and the second flange (22); S12: Place the measuring cylinder (1) vertically on the support, and place the liquid storage tank (2) and the electronic balance (3) directly below the overflow pipe (18); S13: Slowly add water into the grout inlet (16) until water overflows from the overflow pipe (18).

3. The measuring device for the permeability of pulp fiber layer according to claim 1, characterized in that, S2 includes: S21: Add the required pulp fibers to the pulp inlet (16) and let it stand; S22: After the pulp fiber suspension shows obvious stratification, close the sealing cap of the pulp inlet (16); S23: Run the software program in the computer (8), set the air pressure and monitor the position of the porous piston (176). Based on the position information of the porous piston (176), rotate the lifting press (17) to the required position, that is, compress the pulp fiber layer to the specified thickness.

4. The measuring device for the permeability of pulp fiber layer according to claim 1, characterized in that, S3 includes: S31: Keep the air pressure and the liquid level of the upper layer of pulp fiber layer basically stable. After the liquid flow rate from the overflow pipe (18) stabilizes, record the overflow flow rate through the electronic balance (3), that is, the mass of filtrate per unit time. S32: Based on data such as filtration pressure, pulp fiber layer thickness, overflow velocity, liquid viscosity, and filtration area, the permeability of a certain pulp fiber concentration is obtained according to Darcy's law.

5. The measuring device for the permeability of pulp fiber layer according to claim 1, characterized in that, The measuring cylinder (1) includes an upper cover (11), an upper cylinder (12) and a lower cylinder (13). The upper cover (11) and the upper cylinder (12) are connected by a first flange (21). The upper cylinder (12) and the lower cylinder (13) are connected by a second flange (22). An air inlet (14), a pressure sensor (19), a water inlet (15), a liquid level sensor (23) and a slurry inlet (16) are provided on the side wall of the upper cylinder (12). A distance sensor (20) is provided on the outer side of the top of the upper cover (11). The signal lines of the pressure sensor (19), the distance sensor (20) and the liquid level sensor (23) are connected to a data acquisition card (7). The control line of the solenoid valve (4) is connected to the data acquisition card (7) through a first solid-state relay (9). The power line of the diaphragm pump (6) is connected to the data acquisition card (7) through a second solid-state relay (10). The data acquisition card (7) is connected to a computer (8).

6. The measuring device for the permeability of a pulp fiber layer according to claim 5, characterized in that, The upper cover (11) is equipped with a lifting and pressing component (17), which includes a lead screw sleeve (173). The lead screw sleeve (173) is fixedly connected to the inner side of the top of the upper cover (11). A lead screw (172) is rotatably connected inside the lead screw sleeve (173). A handwheel (171) is fixed at the upper end of the lead screw (172). The upper end of the lead screw (172) is rotatably connected to the upper end of a lead screw connector (174). A smooth rod (175) is fixedly connected at the lower end of the lead screw connector (174). The lower end of the smooth rod (175) is fixed on a porous piston (176). A porous mesh is fixed at the lower end of the porous piston (176).

7. The measuring device for the permeability of pulp fiber layer according to claim 5, characterized in that, The distance sensor (20) is used to measure the moving distance of the handwheel (171) on the lifting press (17), and the position of the porous piston (176) is determined by determining the position of the handwheel (171), thereby determining the fiber layer thickness. The pressure sensor (19) is used to measure the air pressure inside the cylinder (1), and the electronic balance (3) is used to record the mass of the overflowing filtrate. The data acquisition card (7) controls the on / off state of the first solid-state relay (9) based on the signal fed back by the pressure sensor (19) to maintain stable air pressure during the measurement process. The data acquisition card (7) controls the on / off state of the second solid-state relay (10) based on the signal fed back by the liquid level sensor, thereby controlling the start and stop of the diaphragm pump (6) to maintain stable liquid level on the porous piston (176).

8. The measuring device for the permeability of pulp fiber layer according to claim 5, characterized in that, The second flange (22) has a first silicone pad (221), a filter screen (222), a porous support (223), and a second silicone pad (224) placed sequentially from top to bottom in the middle. The porous support (223) is a pressure-resistant and corrosion-resistant rigid porous plate, and the outer diameter of the filter screen (222) and the porous support (223) is larger than the inner diameter of the lower cylinder (13); The first silicone pad (221) and the second silicone pad (224) are both annular structures. The outer diameter of the first silicone pad (221) and the second silicone pad (224) is larger than that of the filter screen (222), and the outer diameter of the first silicone pad (221) and the second silicone pad (224) is smaller than that of the second flange (22). The inner diameter of the first silicone pad (221) and the second silicone pad (224) is the same as that of the lower cylinder (13) for flange sealing.

9. The measuring device for the permeability of a pulp fiber layer according to claim 5, characterized in that, The bottom of the lower cylinder (13) has an opening, and the bottom opening of the lower cylinder (13) is connected to the overflow pipe (18). The outlet of the overflow pipe (18) is higher than the top of the flange of the lower cylinder (13) and is placed directly above the liquid storage tank (2).

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