HU181625B - Device for determining and fixing the beating degree of fibre stuff - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to an apparatus for determining and recording the degree of grinding of a fiber with a flow tank containing a constant level of fiber to be measured and connected to a feed line, a mill gauge and the measuring chamber is connected to the filter chamber and to the outside world and is provided with a filtrate level sensing device introduced into the measuring chamber. Specifically, determining the degree of grinding of the fiber means continuously and automatically checking the ability of the fiber to pass through the filter liquid. By definition of milling degree, it is understood that the degree of milling data is generated by regular measurements over a period of time and at a specified frequency, the latter characteristics being determined by the reliable monitoring of the workflow.

Equipment of the kind mentioned in the introduction is usually connected to material conduits such as the fiber material for making the fibreboard. The degree of milling of the fiber material during fiberboard production is controlled to control the milling process of the material in the mill.

Fibreboard is produced from plant fibers having a size of 0.8 and 1.5 mm and a thickness of 0.015 and 0.020 mm. This material is called coarse-milled material with a Schopper-Riegler-30 grinding degree of between 8 and 20 °. This invention relates to a fiber having a degree of grinding that does not exceed a degree of milling of 20 ° according to Schopper-Riegler.

Devices for determining paper milling rates that provide reliable data in the range of 18 to 65 ° according to Schopper-Riegler are known (see Preobrasensky et al., "Spczialnye pribory i regulatory zelljulosno-bumashnogo proizwodstwa", Moscow, 1972, pp. 107-108). and in the range of 60 ° to 98 ° according to Schopper-Riegler (see U.S. Patent 4,089,210). Nowadays, the degree of grinding of fiber is determined by laboratory instruments such as the Schopper-Riegler tester or the defibrator-second tester. However, experience has shown that the sensitivity of the Schopper-Riegler tester between 8 and 25 'and above 90 ° is not satisfactory with respect to the change of 20 milling degrees of the material. The defibrillator tester is more sensitive in this range, but neither device is capable of continuous operation directly connected to the material conduit.

The closest apparatus to the apparatus of the present invention is disclosed in U.S. Patent No. 4,089,210. U.S. Pat. The fiber material is submersible181625

-1181625 Container Feeder is directly connected to the material line. The diver has a cylindrical housing with a screen bottom. Through this the fluid is discharged from the fiber material. The submersible device consists of two interconnected chambers (filter chambers and measuring chambers), the larger one of which is provided with a sieve bottom filter chamber. The dive unit is submerged in and withdrawn from the fiber by compressed air equipment at specified intervals. The device also has a circuit for recording the measurements made. The measurement data measures the level of fluid in the dive instrument by determining the fluid pressure. This is done using a fluid level sensor.

In this known apparatus, the filtrate first enters the interior of the housing of the immersion gauge. The pressure of the filtrate is then the difference between the pressure due to the constant level of fiber in the flow tank and the pressure at the bottom of the dipper.

While in the known apparatus the immersion device is filled with the filtrate, the hydrostatic pressure of the filtrate is reduced, thus the filtration process takes place at varying pressure. This has a detrimental effect on the measurement results of the grinding degree.

In addition, recycled water is used in the process of fiber milling today, which contains a large number of small fiber elements. These small fiber elements clog openings in the bottom of the screen when measuring the degree of milling of the fiber, which makes it impossible to determine the actual milling degree and results in erroneous measurements. All of this makes it very difficult to use known equipment to determine and control the degree of grinding of coarse fiber.

SUMMARY OF THE INVENTION The object of the invention is to provide an apparatus for determining and recording the degree of milling of fiber material, in which the influence of the tiny fibers can be switched off during measurement and pressure variations in the pipeline can be eliminated, i.e. the measurement can be performed under constant pressure. .

A further development, i.e. the invention itself, is that the filter chamber is bounded by a wall with an overflow flange, above which the filter chamber is communicating with the measuring chamber, and the height of the wall measured from the bottom of the screen to the overflow edge is described by:

S h = H-K—,

S where

H is the depth of immersion of the bottom of the sieve into the fiber passing through the flow tank,

And the surface of the screen,

S [cross-sectional area of the overflow rim,

The proportionality factor K, which is between 0.15 and 2, and the measuring chamber is provided with a drainage means after measuring the level of the filtrate. The most important aspect of this solution is that the pressure fluctuations in the material line can be completely turned off, and the filtrate is measured under constant pressure in the measuring chamber.

The filtrate is only exposed to atmospheric pressure here. In addition, if the values given are consistent, filtration conditions can be created in which small fiber fibers do not obstruct the apertures of the screen bottom, and no flow-through layer is formed on the screen bottom.

It is expedient for the filtrate drain device to be formed as a closed drain valve at rest, which is located at the bottom of the measuring chamber.

Another embodiment of the present invention is that the drain valve has a spring-loaded valve stem that extends above the submersible and is provided with a head, and the drive submersible in the flow tank is formed as a hydraulic cylinder with the submerged end of the submersible it is.

According to a further preferred embodiment of the invention, the measuring chamber may consist of two parts which are interconnected by a flexible hose. A portion of the weighing chamber is located outside the flow vessel and is provided with a filtrate level sensing device, and the filtrate discharge means is formed as a hinge connecting a portion of the weighing chamber to the weighing chamber and a tensile bar connected to the piston rod of the cylinder.

Further details of the invention will be illustrated with reference to the accompanying drawings in connection with exemplary embodiments.

In the drawing, Figure 1 is a schematic diagram of a preferred embodiment of the device according to the invention, Figure 2 is a detail of the diagram of Figure 1, but in other embodiments, Figure 3-6. Figure 1 is a detail of the sketch of Figure 1; submersible gear in various embodiments.

As shown in Fig. 1, the upper half of the flow container 1 is arranged in a material conduit 2 with its lower part. Through this conduit 2, the fiber material is supplied to the machine on which the fibreboards are made in this embodiment.

The overflow container 1 is arranged in an overflow container 3 which is connected via a drain pipe 4 to the material pipe 2 or the fiber bath. More particularly, the drain pipe 4 is connected to the branch of the material conduit 2 through which the fiber material is fed to the machine.

Fibrous material is continuously introduced into the overflow container 1, after which it enters the overflow container 3. Thus, the fiber level in the flow container 1 is constant, i.e. the flow container 1 is constantly filled. We would like to determine the degree of grinding of this flowable fiber material. The foregoing also means that the fiber material is constantly flowing in the flow vessel 1, so that its stock is constantly renewed, so that the milling degree can always be measured on a new and continuously renewable material.

The flow vessel 1 is provided with a submersible device 5, which is provided with a drive for submersing and lifting it at intervals. This drive in this embodiment is a cylinder 6 which is operated with a fluid under pressure and with a timing relay 8 and a guiding block 7. Control block 2181625 controls the flow of pressurized fluid from source 9 to cylinder 6 by means of control block 7 and time relay 8.

Of course, not only the hydraulic cylinder 6 but also the pneumatic cylinder or any other drive may be used for the dive instrument 5.

Thus, it has been seen that the working cylinder 6 of the dipper 5 is connected to the control block 7 controlled by the time relay 8. As a result of the operation of these devices, the dive device 5 is immersed to a certain depth in the fibrous material contained in the container 1 and, after a certain time, is removed from it. For example, if the aforementioned source 9 provides compressed air and the drive is a pneumatic cylinder 6, conventional elements such as an oil atomizer 10, a pressure relief valve 11 and an associated compressed air purifying filter 12 may also be provided. When the time relay 8 is triggered, the control block 7 actuates the cylinder 6, causing the dipper 5 to submerge in the fiber material, and at the same time the grinding degree is determined and recorded.

The submersible instrument 5 for determining the degree of grinding actually has a filter chamber 13 with a screen bottom 14 and a measuring chamber 15 connected to the filter chamber 13 and the environment. The measuring chamber 15 is at least partially above the filtering chamber 13 (Figures 1 and 2). As can be seen in the figures, the filter chamber 13 and the measuring chamber 15 are connected to one another via a wall passage 31 and an overflow flange 16. The overflow flange 16 is slightly deeper than the constant maximum fluid level in the overflow container 1. If the distance between the bottom of the screen 14 and the overflow flange 16 is denoted by h, it can be determined by the following relationship:

S h = H ~ K—,

S where

H is the depth of immersion of the bottom of the screen 14 into the fiber passing through the container 1,

And the surface of the 14 screens,

Sj is the cross-sectional area of the overflow flange 16 and the proportionality factor K, which is between 0.15 and 2.

Also included in the measuring chamber 15 of the diving device 5 is a device which senses the height of the liquid level in the measuring chamber 15. For this purpose, any device known per se, such as a float, electrical contacts, etc., may be used. In this embodiment, a compressed air mixing tube 17 is used, which is introduced into the measuring chamber 15 and connected by means of a flexible hose 18 to the recording means obtained and to a compressed air source 19.

The means for recording the measurement results include a pressure gauge, such as a known differential pressure gauge 20, which is connected to a differential transformer not shown. A comparator 21 and an electromechanical transducer 22 are connected to the differential pressure gauge 20, which provides a signal to the recording device 23.

A flow controller 24 is provided between the source 19 and the compressed air mixing tube 17, which provides for the delivery of compressed air to the mixing tube 17. There are also 25 pressure relief valves and 26 filters.

The operation of the recording system for measuring results is based on the determination and monitoring of the pressure created by the liquid level in the measuring chamber 15 and is described in detail in U.S. Patent No. 4,089,210.

U.S. Pat.

The pressure in the mixing tube 17 is measured using a differential pressure gauge 20. The fluid under pressure is introduced into one of the two chambers of the differential pressure gauge 20, while the other chamber is connected to the outside world to eliminate pressure fluctuations due to environmental influences.

The change in pressure drop across the chambers of the differential pressure transducer 20 causes a shift in the core of the differential transformer not shown, resulting in a change in voltage and phase at the output of the differential pressure transducer 20. This is used in comparator 21 to record the fluid level fluctuation of the measuring chamber 15.

Comparator 21 has two microcap channels not shown, which are adjusted according to the height of the liquid level. Thus, one of the microswitches will sound when the minimum fluid level in the measuring chamber 15 is reached and the other when the fluid level reaches its maximum height.

The height of the liquid column between these two values represents the measuring range, but for this the fluid in the filter chamber 13 is not taken into account. The level of liquid present here is influenced by the quantity and quality of material deposited on the bottom 14 of the screen. It will be appreciated that, according to the minimum and maximum fluid levels, minimum or maximum air pressure is generated in the mixing tube 17, respectively.

The data evaluation and display unit provides a finished unit signal that characterizes the filterability of the fiber 35, the degree of grinding. This signal is proportional to the time between two microswitches in the comparator 21. From the data evaluation and display unit, the signal is transmitted to the recording device 23, but can also be fed to a computer for controlling the degree of pulping of the fiber.

High pressure water stroke may also occur in the material conduit 2, resulting in a faulty signal. To avoid this, the entire apparatus, the material conduit 2, is arranged through a flow connection 27, through which the fiber 45 to be measured is introduced into the flow container 1.

The expanding cone of the passageway 27, whose walls thus open upwards in the direction of flow, is constantly increasing in cross-section. This is the design chosen for greater clarity, but of course other passageways 27 having a ke50 cross-section can be imagined with the same utility.

Further, a baffle 28 may be provided at the bottom of the flow container 1 at the entrance of the flow passage 27.

In the case of the filter chamber 13, it is also possible to make the side wall 29 of the filter 55 permeable. This wall 29 is formed as a unit with the side wall 30 of the measuring chamber 15. In this example, the filter chamber 13 is stored at its largest cross-section partly by the bottom 14 and the wall 29, and at its smallest cross-section partly by the wall 31. This wall defines an overflow pipe 31 having an overflow flange 16 formed at its upper end, through which the filtering chamber 13 and the measuring chamber 15 are in contact with each other. The filtering chamber 13 and the measuring chamber 15 are further separated from each other by the bottom 32 of the measuring chamber 15. This bottom 32 is located in this case 3181625 where the wall 29 passes into the side wall 30.

This transition, or the bottom 32, is at a depth below the separation between the two chambers that results from the sum of the measuring range and the height of the filtrate. This means that the separation between the chambers and the overflow flange 16 are at the same height above the bottom 32 of the measuring chamber 15. The wall 31 is fixed to the bottom 32, where the bottom 32 has an opening. Thus, the filter chamber 13 has a smaller cross-section than the bottom 14.

In this embodiment of the apparatus of the invention, the filtrate drain device is a drain valve 33 formed in the bottom 32. The number of drain valves 33 can be set to the value required for effective operation, in contrast to the two illustrated herein. The drain valve 33 has a valve stem 35 supported by springs 34, the head 36 of which extends from the measuring chamber 15 of the dip 5. This head 36 cooperates with a stop 37 secured to the cylinder 6.

The apparatus according to the invention operates as follows. At intervals determined by the timing relay 8, the submersible device 5 is submerged in a flow container 1 having a constant fluid level. This immersion is performed to a predetermined depth while constant pressure is exerted on the bottom 14 of the filter chamber 13. After immersion of the submersible device 5, the fiber material enters the filter chamber through the screen bottom 14, fills it and flows through the overflow flange 16 into the measuring chamber 15. In this case, the filtration process takes place under constant pressure drop zlH = H-h, where H is the depth of immersion of the screen bottom 14 of the filter chamber 13 into the fiber material and h is the distance between the screen bottom 14 and the overflow flange 16. The flow of filtrate through the overflow tube defined by the wall 31 is determined by the flow resistance which is overcome by the filtrate passing through the overflow 16. This flow resistance depends on the ratio of the cross-sectional area (S) of the filter chamber 13 to the overflow pipe defined by the wall 31, i.e. the cross-sectional area (S _t ) of the overflow flange 16. These two surfaces are predefined

Í ^S) ratio of 1 - I can provide the necessary filtering mérVsJ supply line, for which is not adhered to the small fiber elements 13 between the filtration chamber 14 sieve plates deposited fibers.

Measurement of the filtrate level in the measuring chamber 15 is carried out already when the fiber layer is formed on the screen bottom 14, so that the fluctuations in the fiber concentration do not affect the measurement results. The feed rate and the amount of filtrate recorded by the recorders are also varied according to the degree of grinding. After the measurement, the submersible device 5 is lifted out of the flow tank 1 by means of the cylinder 6 and moved to the upper extreme position of the cylinder 6. Meanwhile, the heads 36 of the valve stem 35 are pressed against the stop 37, causing the drain valves 33 on the bottom 32 to open against the spring 34, flowing out of the fluid chamber containing the fibrous material from the measuring chamber 15, and wiping off the fibrous layer. The unit is then ready for the next measurement.

Fig. 2 is a schematic diagram of another embodiment in connection with a detail of Fig. 1 showing the flow container 1 and other associated elements. Here, the bottom 32 of the measuring chamber 15 is formed in one piece. In addition, the measuring chamber 15 is comprised of two parts, one of which is designated 15a and is located outside the measuring chamber. They are interconnected by a flexible hose 38 which is guided on a roller 39. The agitator tube 17 for sensing the filtrate level is introduced into this outer portion 15a. The portion 15a is connected by a hinge 40 to the side of the overflow container 3, around which the portion 15a is pivoted during emptying. For this purpose, a portion 15a is connected to the piston rod 42 of the cylinder 6 by means of a pull rod 41. Figure 2 also shows the position during measurement when the cylinder 6 is in the lower extreme position. In this case, the pull rod 41 holds the outer part 15a of the measuring chamber 15 in the position shown. After completion of the measurement, the cylinder 6 moves upwardly with its piston rod 42 and also displaces the associated tensile bar 41. As part of this, the portion 15a is pivoted about the hinge 40 so that fluid flows therefrom into the overflow container 3. Thus, this embodiment differs from that shown in Fig. 1 in the design of the device for draining the filtrate after measurement, in other respects.

In the embodiment not shown separately, the drain device may also be configured as an electromagnetic valve controlled by the time relay 8.

Thus, it is clear from the foregoing that the apparatus of the present invention can be used with high sensitivity and measurement accuracy to determine and record the degree of grinding of the fiber material, even when using water recycled from the process and containing small fiber elements. The apparatus of the present invention also enables automatic control of the milling process, whereby the electricity requirement of the milling can be reduced and the quality of the products produced can be greatly increased.

3-6. abia shows different embodiments for the various configurations of the measuring chamber 15 and the filter chamber 13, in particular for drainage of the filtrate. These self-explanatory embodiments also show that a wide variety of embodiments of the device of the present invention are conceivable.

Claims (4)

Patent claims 1. Apparatus for determining and recording the degree of milling of the fiber by means of a continuous tank containing the fiber to be measured and connected to the pipeline, a submersible means for measuring the degree of milling, and a submersible means for connected to the filter chamber and to the outside world and provided with a filtrate level sensing device introduced into the measuring chamber, characterized in that the filter chamber (13) is bounded by a wall (31) provided with an overflow flange (16) above which the filter chamber (13) connected, the height (h) of the wall (31) from the bottom of the screen (14) to the overflow flange (16) is described by the following relationship: -4181625 S h = H — K— S where H is the depth of immersion of the screen bottom (14) into the fiber passing through the flow vessel (1), And the surface of the bottom of the screen (14), S | a cross-sectional area of the overflow flange (16) and a proportional factor K of between 0.15 and 2, and the measuring chamber (15) is provided with a drainage means from the measuring chamber (15) after measuring the level of the filtrate. An embodiment of the apparatus according to claim 1, characterized in that the filtrate drainage means is formed in the form of a closed drain valve (33), which is arranged at the bottom (32) of the measuring chamber (15). An embodiment of the device according to claim 2, characterized in that the drain valve (33) has a valve stem (35) with a spring (34) provided with a head (36) extending over the dive device (5), the diving device (5). and the drive unit immersed in the flow container (1) is formed as a working cylinder (6) having a stop (37) cooperating with the head (36) in the fully raised position of the dipper (5). An embodiment of the apparatus according to claim 1, characterized in that the measuring chamber (15) consists of two parts which are connected by means of a flexible hose (38), one part (15a) of the measuring chamber (15) on the flow container (1). ) is provided externally and provided with a filtrate level sensing device, and the filtrate drain device 15 is a hinge (40) connecting one part (15a) of the measuring chamber (15) to the overflow tank (3) and a part (15a) of the measuring chamber (15). is formed as a draw bar (41) connected to the piston rod (42) of the cylinder (6).